JP4115374B2 - Robot device - Google Patents

Description

  The present invention relates to a multi-axis drive system mechanical device such as a robot, a general-purpose assembly device, a robot / hand device, and other multi-axis control devices, and in particular, a position control including a proportional gain of phase compensation and a phase compensation element. The present invention relates to a robot in which each joint part is constituted by a servo controller of an actuator constituting the system.

  More particularly, the present invention relates to a bipedal legged mobile robot in which each axis link is controlled by high gain PD control, and in particular, the characteristics of the actuator itself during the motion of the entire body during a fall or fall. The present invention relates to a legged mobile robot that realizes stable and highly efficient operation by dynamically or statically controlling two of the characteristics of an actuator controller.

  In addition, the present invention dynamically or statically controls two of the characteristics of the actuator itself and the characteristics of the controller of the actuator when performing various motions, such as a rising motion from a prone or supine posture. The present invention relates to a legged mobile robot that realizes stable and highly efficient operation.

  A mechanical device that performs a movement resembling human movement using an electrical or magnetic action is called a “robot”. It is said that the word “robot” comes from the Slavic word “ROBOTA (slave machine)”. In Japan, robots started to spread from the end of the 1960s, but many of them are industrial robots such as manipulators and transfer robots for the purpose of automating and unmanned production operations in factories. Met.

  A stationary type robot such as an arm type robot that is implanted and used in a specific place operates only in a fixed / local work space such as assembly / sorting of parts. On the other hand, a mobile robot has a non-restricted working space, and can freely move on a predetermined route or a non-route to perform a predetermined or arbitrary human work, Alternatively, it can provide a wide variety of services that replace other life forms. In particular, legged mobile robots are more unstable than crawler and tire type robots, making posture control and walking control more difficult. It is excellent in that it can realize flexible walking / running operation regardless of the type.

  Recently, the model is based on the body mechanism and movement of a four-legged animal, such as a dog or a cat, or a pet-type robot that mimics its movement, or a human-like animal that walks upright on two legs. Research and development related to legged mobile robots such as designed “humanoid” or “humanoid” robots have progressed, and expectations for practical use are also increasing.

  A number of techniques relating to posture control and stable walking have been proposed for robots of the type that perform legged movement by biped walking. Stable “walking” as used herein can be defined as “moving using legs without falling down”. A biped robot such as a humanoid has a higher center of gravity and a lower stability during walking than a quadruped. For this reason, the problem of posture stabilization is particularly important in a biped robot.

  Robot posture stabilization control is very important in avoiding robot overturning. This is because a fall means that the robot is interrupting the work being executed, and a considerable amount of labor and time are spent to get up from the fall state and resume the work. In addition, there is a risk of causing fatal damage to the robot body itself or the object on the other side that collides with the falling robot when it falls.

  At the time of walking, gravity and inertial force and these moments act on the road surface from the walking system due to gravity and acceleration generated during walking motion. According to the so-called “Dalambert principle”, these forces and moments balance with the floor reaction force and the floor reaction force moment as a reaction from the road surface to the walking system. As a result of dynamic reasoning, there is a point where the pitch and roll axis moment become zero inside the support polygon formed by the sole contact point and the road surface, that is, “ZMP (Zero Moment Point)” (for example, non-patent) Reference 1). Many of the proposals related to posture stability control of legged mobile robots and prevention of falls during walking use this ZMP as a norm for determining the stability of walking. Using ZMP as a stability determination criterion means that a trajectory is treated as a target value in motion control, not a force, so that technical feasibility increases. Further, according to the biped walking pattern generation based on the ZMP norm, there is an advantage that a foot landing point can be set in advance and it is easy to consider the kinematic constraint conditions of the foot according to the road surface shape.

  The posture stability control of a robot using ZMP as a stability criterion is basically to search for a point where the moment becomes zero inside the support polygon formed by the ground contact point and the road surface (for example, , See patent documents 1-5).

  Of course, in spite of the maximum attitude stability control to prevent the aircraft from tipping over, the control is inadequate or unforeseen external factors (such as unexpected collision with objects, floor protrusions and depressions) Depending on the road surface condition, the appearance of obstacles, etc., the posture may become unstable and cannot be supported by the movable legs alone, and the robot may fall.

  For example, in a situation where a legged mobile robot is likely to fall, control the robot to lower the center of gravity of the robot, so that the robot can be damaged from the floor and other collision objects when it falls, and damage to the object that is the collision partner. Can be reduced. However, in order to minimize damage in the event of a fall, discussions have been made on how to operate the entire aircraft, including the torso and arms, as well as the legs. Not.

  Further, in the case of an upright walking type legged mobile robot, when taking into account a body motion such as walking, the reference posture is a standing posture that stands up with two legs. For example, the most stable state (that is, the minimum point of instability) in the standing posture can be set as the basic standing posture.

  However, in order to maintain the basic standing posture stably, driving power is required for executing posture stabilization control and generating torque of a joint shaft motor such as a leg by a control instruction. That is, since the standing posture is never stable in the non-powered state, it is considered preferable that the robot starts starting from the physically most stable posture on the floor, such as lying on its back or lying down. Here, a problem arises that when the robot is turned on in a floor position, the robot must wake up autonomously and cry. It would be cumbersome for the operator to lend a hand, lift the aircraft, and raise the robot.

  In addition, “falling” is inevitable when the robot operates in a human living environment that includes various obstacles and unexpected situations. In the first place, the human itself falls. Even in such a case, it is still troublesome for the operator to lend a hand, lift the aircraft, and stand the robot.

  By the way, a multi-axis drive system mechanical device generally has a large number of joint degrees of freedom, and the movement of the joint is realized by an actuator motor. In this case, the rotation position, rotation amount, and the like of each motor can be taken out, and a desired operation pattern can be reproduced and attitude control can be performed by servo control. In general, each joint portion viewed from the motion control theory is controlled by high gain PD control, and each axis link is operated with a certain characteristic.

  However, as can be seen from the results of human movement research, in order to achieve stable and highly efficient movement, it is necessary to increase or decrease the force locally and increase or decrease the compliance (mechanical passivity) of each joint part. is important.

  When the movement of each joint axis is considered as a position control system, it is better to use a servo controller with a high gain and a high bandwidth so that the control deviation is reduced. On the other hand, when the motion of each axis of the joint is considered as a dynamic model, it is possible to lower the gain and raise / lower the frequency band for phase compensation in consideration of the action of potential energy and kinetic energy. You should do it.

  However, in order to realize such control on the robot body, a function for dynamically or statically controlling the characteristics of the actuator itself and the characteristics of the actuator controller is required.

  For example, proposals have been made regarding walking control devices for legged mobile robots that can stably walk on known or unknown walking surfaces. In other words, when the bipedal legged mobile robot has a human body-like structure with arms on the upper body, when the frictional force decreases on the walking road surface and the stability decreases, the state is driven and stabilized. Is secured or recovered (for example, see Patent Document 7). However, this is realized by controlling the feed-forward gain, and there is no mention of joint viscosity and frequency characteristics, and there is no concept of compliance.

JP-A-5-305579 JP-A-5-305581 JP-A-5-305583 JP-A-5-305585 JP-A-5-305586 JP-A-11-48170 JP-A-7-205069 Miomir Vukobratovic's “LEGGED LOCATION ROBOTS” (Ichiro Kato's “Walking Robot and Artificial Foot” (Nikkan Kogyo Shimbun))

  An object of the present invention is to provide an excellent legged mobile robot that can reduce damage to the robot as much as possible by controlling the movement of the entire body including the torso and arms as well as the legs in the course of falling or falling. There is to do.

  A further object of the present invention is to provide stable and highly efficient control by dynamically or statically controlling two of the characteristics of the actuator itself and the characteristics of the controller of the actuator during the movement of the entire aircraft during the fall or fall. An object is to provide an excellent legged mobile robot capable of realizing movement.

  A further object of the present invention is to dynamically or statically control two of the characteristics of the actuator itself and the characteristics of the controller of the actuator when performing various movements, such as rising from a lying or lying posture. It is an object of the present invention to provide an excellent legged mobile robot capable of realizing stable and highly efficient operation.

The present invention has been made in consideration of the above problems, and the first aspect thereof is a legged mobile robot including a plurality of joints including a plurality of movable legs,
Actuator characteristic control means for combining the gain and phase compensation control of the servo controller of the actuator for driving each joint and the control of the viscous resistance of the actuator motor,
The actuator characteristic control means includes a first actuator characteristic for increasing the low-frequency gain, reducing the phase advance amount, and increasing the joint viscous resistance at each stage of the overturning operation. Switching between the second actuator characteristic that decreases the low-frequency gain, increases the phase advance amount, and decreases the viscous resistance of the joint,
This is a legged mobile robot.

  According to the present invention, in the servo controller of the actuator that constitutes each joint part of the legged mobile robot, by adjusting the proportional gain and the phase compensation element, the positioning accuracy required for each part of the joint of the robot, mechanical passive (Compliance) and operation speed can be set arbitrarily.

  In addition, when the coil of the actuator / motor is not energized, the coil is intermittently switched to a short circuit state or an open state, thereby adjusting the viscous resistance of the motor and changing the robustness against disturbances such as vibration.

  Furthermore, by combining the gain and phase compensation control in the servo controller of these actuators with the control of the viscous resistance of the actuator and motor, the frequency characteristics of the actuator that can be applied to the parts where positioning accuracy is important, or high-speed response It is possible to obtain the frequency characteristic of the actuator that can be applied to a portion where (that is, high-speed response) and compliance are important.

  Here, the actuator characteristic control means sets the actuator characteristics to “large low-frequency gain”, “small phase advance amount in high-frequency region”, and “large joint viscous resistance”. Accurate positioning control is possible, and posture stability is increased. Therefore, the characteristics of the actuator for driving each joint where positioning accuracy is prioritized at each stage of the overturning operation are the first actuator that increases the low-frequency gain, decreases the phase advance amount, and increases the joint viscous resistance. It is good to set to the characteristic.

  In addition, the actuator characteristic control means performs mechanical passive by setting the actuator characteristics to “low gain in the low band”, “large phase advance amount in the middle / high band”, and “low in the joint viscous resistance”. Therefore, high-band follow-up control can be performed while relaxing the impact force at the moment of landing. Therefore, at each stage of the overturning operation, the characteristics of the actuator for driving each joint where mechanical passiveness or high-speed response is prioritized, the low-frequency gain is reduced, the phase advance amount is increased, and the joint viscous resistance is increased. It is preferable to set the second actuator characteristic to be reduced.

  The airframe of the legged mobile robot is composed of a multi-link structure in which a plurality of joint axes having substantially parallel joint degrees of freedom are connected in the length direction. In the course of the overturning operation, the link state formed by the landing part of the multi-link structure and the floor surface is switched several times between the open link state and the closed link state. In each stage where the link state is switched in this way, the characteristics prioritized by the actuator for driving each joint are switched among positioning accuracy, mechanical passivity or high-speed response, and accordingly, the first Switching between the actuator characteristic and the second actuator characteristic may be performed.

  Here, the legged mobile robot uses a floor reaction force sensor or an acceleration sensor arranged on the sole or an acceleration sensor arranged on the waist position of the trunk while performing the legged work in a standing posture. An external force applied to the aircraft is detected. Then, based on these detected external forces, a ZMP balance equation is established, and a ZMP in which the moment applied to the aircraft is balanced is arranged on or inside the side of the support polygon formed by the sole contact point and the road surface. In addition, the attitude stability control of the aircraft is performed by always planning the ZMP trajectory.

  However, the moment error on the ZMP balance equation cannot be canceled due to excessive external force applied to the aircraft or unfavorable road surface conditions. It may be difficult or impossible to arrange the ZMP. In such a case, the legged mobile robot according to the present invention gives up the attitude stability control of the airframe and performs a predetermined overturning operation so as to minimize the damage to the airframe when falling to the floor. It has become.

  That is, in the event of a fall, a landing site where the change amount ΔS / Δt per unit time Δt of the area S of the support polygon formed by the ground contact point of the aircraft and the road surface can be minimized is searched. The target landing point to be landed by the selected region is set so that the change ΔS / Δt per unit time Δt of the area S of the support polygon formed by the To floor. And the support polygon newly formed by landing a site | part is further expanded.

  Then, until the position energy of the airframe is minimized and the overturning operation is completed, a part where ΔS / Δt is minimized is searched, and the part is landed on a target landing point where ΔS / Δt is minimized. The operation and the operation of enlarging the newly formed support polygon are repeatedly executed.

  In this way, by following the policy of minimizing the amount of change ΔS / Δt per time t of the area S of the support polygon and maximizing the support polygon when the floor is dropped, The impact received from the floor when falling can be dispersed throughout the body, minimizing damage.

  The actuator characteristic control means maintains the characteristics of the actuator for driving each joint related to stable region control at each stage of the overturning operation, increases the low frequency gain, decreases the phase advance amount, and maintains the joint viscous resistance. By doing so, it is possible to perform highly accurate positioning control of each of these joint parts and increase the stability of the posture. As a result, the positioning accuracy of the joint, which is the main component for controlling the amount of ΔS / Δt, which is a standard for controlling the overturning motion of the aircraft, is ensured, and the stability of the operation can be increased.

  In addition, the actuator characteristic control means determines the characteristics of the actuator for driving each joint related to potential energy control at each stage of the overturning operation, increases the low-frequency gain, decreases the phase advance amount, and reduces the joint viscous resistance. By switching from the increased first actuator characteristics to the second actuator characteristics that reduce the low-frequency gain, increase the phase advance amount, and reduce the viscous resistance of the joints, these joint parts are mechanically passive (compliance). And fast responsiveness.

  As a result, it is possible to perform high-band follow-up control while having mechanical passivity (compliance) when the leg performs a passive operation using potential energy.

  Furthermore, by switching the characteristics of the actuator for driving each joint related to impact buffering at the time of landing to a second actuator characteristic that reduces the low-frequency gain, increases the phase advance amount, and decreases the viscous resistance of the joint, These joint sites should have mechanical passivity (compliance) and quick response.

  As a result, by giving mechanical passivity (compliance) at the moment of landing, the entire robot becomes a soft system, so that the impact applied to the entire body can be reduced.

The second aspect of the present invention is a legged mobile robot composed of a plurality of joint parts including a plurality of movable legs,
Actuator characteristic control means for combining the gain and phase compensation control of the servo controller of the actuator for driving each joint and the control of the viscous resistance of the actuator motor;
A rising motion control means for controlling the rising motion from the sleeping posture of the aircraft,
The actuator characteristic control means includes a first actuator characteristic for increasing the low-frequency gain, reducing the phase advance amount, and increasing the viscous resistance of the joint. Switching between the second actuator characteristic that reduces the low-frequency gain, increases the phase advance amount, and decreases the viscous resistance of the joint.
This is a legged mobile robot.

  According to the present invention, in the servo controller of the actuator that constitutes each joint part of the legged mobile robot, by adjusting the proportional gain and the phase compensation element, the positioning accuracy required for each part of the joint of the robot, mechanical passive (Compliance) and operation speed can be set arbitrarily.

  In addition, when the coil of the actuator / motor is not energized, the coil is intermittently switched to a short circuit state or an open state, thereby adjusting the viscous resistance of the motor and changing the robustness against disturbances such as vibration.

  Furthermore, by combining the gain and phase compensation control in the servo controller of these actuators with the control of the viscous resistance of the actuator and motor, the frequency characteristics of the actuator that can be applied to the parts where positioning accuracy is important, or high-speed response Thus, it is possible to obtain the frequency characteristics of the actuator that can be applied to a portion where compliance is important.

  Here, the actuator characteristic control means sets the actuator characteristics to “large low-frequency gain”, “small phase advance amount in high-frequency region”, and “large joint viscous resistance”. Accurate positioning control is possible, and posture stability is increased. Therefore, at each stage of the rising operation, the characteristics of the actuator for driving each joint where positioning accuracy is given priority are the first actuator that increases the low-frequency gain, decreases the phase advance amount, and increases the joint viscous resistance. It is good to set to the characteristic.

  In addition, the actuator characteristic control means can set the characteristics of the actuator to “low gain in the low band”, “increase the phase advance amount”, and “decrease the viscous resistance of the joint”, so that the mechanical passivity is fast. Since responsiveness can be provided, high-band follow-up control can be performed while reducing the impact force at the moment of landing. Therefore, at each stage of the rising motion, the characteristics of the actuator for driving each joint where mechanical passiveness or high-speed response is prioritized, the low-frequency gain is reduced, the phase advance amount is increased, and the joint viscous resistance is increased. It is preferable to set the second actuator characteristic to be reduced.

  The body of the legged mobile robot is composed of a multi-link structure in which a plurality of joint axes having substantially parallel joint degrees of freedom are connected in the length direction. In the process of getting up, the link state formed by the floor portion of the multi-link structure and the floor surface is switched several times between the open link state and the closed link state. In each stage where the link state is switched in this way, the characteristics prioritized by the actuator for driving each joint are switched among positioning accuracy, mechanical passivity or high-speed response, and accordingly, the first Switching between the actuator characteristic and the second actuator characteristic may be performed.

  The link structure is formed by connecting at least a shoulder joint pitch axis, a trunk pitch axis, a hip joint pitch axis, and a knee pitch axis in the height direction of the aircraft. Of course, the body of the legged mobile robot may have a joint pitch axis other than these, and each joint part may have a degree of freedom of rotation about the roll axis other than the pitch axis and the yaw axis. Good.

The rising motion control means is
Means for searching for the narrowest support polygon formed with the smallest number of links in the ground contact polygon formed by the floor contact link in the above-ground posture in which two or more links including the center of gravity link serving as the center of gravity of the airframe are in contact with the floor; ,
Means for leaving the flooring link other than the searched support polygon in the ground contact polygon;
Means for bending two or more continuous bed leaving links and contacting the ends of the link ends to form a narrower ground contact polygon;
In response to the support polygon becoming sufficiently narrow, means for leaving the first predetermined number of links or more upright from one end side of the link structure,
Can be configured. Here, the polygon formed by the end portions of the plurality of aircrafts in contact with the floor is called a grounded polygon. In addition, the contact polygon in which ZMP exists is called a support polygon. The stable region of ZMP is a region in which the posture of the robot can be stably controlled within the support polygon.

When the legged mobile robot is in a basic position on the floor such as lying on its back or lying down, all links connecting the shoulder joint pitch axis, trunk pitch axis, hip joint pitch axis, and knee pitch axis are in contact with the floor. In the basic standing posture and walking posture, all the links connecting the joint pitch axis, trunk pitch axis, hip joint pitch axis, and knee pitch axis leave the floor and are aligned in a substantially vertical direction.

  When getting up from the floor posture to the standing posture, higher torque output is required for the joint actuators involved than when maintaining a normal standing posture or performing a walking motion. For this reason, the raising operation is realized with a smaller driving torque by performing the raising operation using the posture in which the ZMP support polygon is minimized.

  First, in the on-floor posture in which almost all the links are in contact with the floor, the narrowest support polygon is searched for in the ground contact polygon formed by the floor contact links. At this time, it is determined whether or not ZMP can be planned when at least two or more links are removed from one end of the aircraft. For example, a narrower support polygon is searched for while maintaining the floor contact state with the link connecting the trunk pitch axis and the hip joint pitch axis as the center of gravity link. Then, two or more links that are continuous from one end side including the shoulder joint pitch axis are attempted to leave the floor.

  Next, leaving the floor contact link to be a support polygon, two or more continuous links are left from one end side of the ground contact polygon. Then, one or more leaving links are bent from one end side to land the end of the link end to form a narrower ground contact polygon. For example, two or more links including the shoulder joint are left from one end side of the link structure as links not involved in the support polygon. Then, in a state where two or more links including the shoulder joint are leaving the floor, the arm is bent along the shoulder joint pitch axis, and the hand that is the end of the link end is brought into contact with the floor. Then, by gradually approaching the hand to the trunk pitch axis side, which is the position of the center of gravity of the aircraft, a grounding polygon narrower than the original on-floor posture is formed.

  Further, the narrowest support polygon is searched for in this ground contact polygon. This time, at least two or more links are removed from the other end to determine whether the ZMP can be planned. For example, while maintaining the center-of-gravity link connecting the trunk pitch axis and the hip joint pitch axis in a floor contact state, an attempt is made to leave two or more continuous links from the other end side including the knee joint pitch axis.

  Next, the floor contact link that becomes the support polygon is left, and two or more continuous links are removed from the other end side of the ground contact polygon. Then, one or more floor links are bent from the other end side to land the end portion of the link end to form a narrower ground contact polygon. For example, in a state where two or more links including the knee joint are leaving the floor, the knee joint is bent along the pitch axis, and the sole which is the end of the link end is brought into contact with the floor. Then, a ground contact polygon narrower than the original on-floor posture is formed by gradually approaching the sole to the hip joint pitch axis side that is the position of the center of gravity of the aircraft.

  Next, it is determined whether or not the support polygon has become sufficiently narrow depending on whether or not the center-of-gravity link can be removed while the ends of both link ends of the ground contact polygon are in contact with each other. For example, the support polygon is determined depending on whether or not the center-of-gravity link connecting the trunk pitch axis and the hip joint pitch axis can be removed while the hand and the sole as the ends of both link ends of the ground polygon are in contact with the floor. Judge whether or not it is sufficiently narrow.

  Then, in response to the support polygon that the landing site is sufficiently narrowed, the center-of-gravity link is left in the state where the ends of both link ends of the support polygon are in contact with the floor, While maintaining the ZMP in the support polygon formed by the landing link, the distance between the end portions is reduced at both link ends of the support polygon, and the ZMP is moved to the other end side of the link structure. For example, the center-of-gravity link connecting the trunk pitch axis and the hip joint pitch axis with the hands and soles as the ends of both ends of the contact polygon in contact with the floor is removed from the floor, and the distance between the hands and the soles is gradually increased. The ZMP is moved toward the sole.

  Then, in response to the ZMP having entered the ground polygon formed by only the second predetermined number of floor-contact links or less from the other end of the link structure, the ZMP is accommodated in the ground polygon. The rising operation is completed by leaving the first predetermined number of links or more from the one end side of the link structure and extending the leaving link in the length direction. For example, a link from the shoulder pitch axis to the knee pitch axis while the ZMP is accommodated in the grounding polygon in response to ZMP entering the grounding polygon formed by the sole. By lifting the floor and extending the floor link in the length direction, the rising operation can be completed.

  The actuator characteristic control means increases the low-frequency gain, the characteristics of the actuator for driving each joint of the floor contact link involved in the search for the narrowest support polygon in each stage of the rising motion of the aircraft. The first actuator characteristic may be set to reduce the phase advance amount and increase the joint viscous resistance.

  In this way, by setting the low gain of the actuator of the corresponding joint part to be large, the phase advance amount to be small, and the viscous resistance of the joint to be large, high-accuracy positioning is possible, and the size of the support polygon Accuracy can be ensured.

  In addition, the actuator characteristic control means is configured to reduce the characteristics of the actuator for driving each joint of the floor link that does not participate in the support polygon during the period until the floor is touched to form a narrower ground contact polygon. From the second actuator characteristic in which the gain is reduced, the phase advance amount is increased, and the joint viscous resistance is reduced, the first low frequency gain is increased, the phase advance amount is reduced, and the joint viscous resistance is increased after the floor contact. You may make it switch to an actuator characteristic.

  In this way, by giving mechanical passivity (compliance) and high-speed response to the corresponding joint parts, the movement and wearing of arms and legs are performed in the process of successively forming narrower grounding polygons for getting up. The floor operation becomes smooth and energy consumption can be reduced.

  In addition, the actuator characteristic control means has a characteristic of an actuator for driving each joint related to an operation of erecting the airframe in response to the support polygon becoming sufficiently narrow, a large low-frequency gain, and a phase advance amount. May be set to a first actuator characteristic that increases the viscous resistance of the joint.

  When the actuator of the corresponding joint part is set to increase the low frequency gain, decrease the phase advance amount, and increase the viscous resistance of the joint, enabling high-accuracy positioning and returning to the upright posture Posture stability control can be realized.

  According to the present invention, it is possible to provide an excellent legged mobile robot capable of reducing damage to the robot as much as possible through motion control of the entire body including the torso and arms as well as the legs in the course of falling or dropping. can do.

  In addition, according to the present invention, stable and high efficiency can be achieved by dynamically or statically controlling the characteristics of the actuator itself and the characteristics of the actuator controller during the movement of the entire body during the fall or fall. It is possible to provide an excellent legged mobile robot capable of realizing various operations.

  Further, according to the present invention, it is possible to provide an excellent legged mobile robot that can autonomously recover from a standing posture such as lying on its back or lying down.

  In addition, according to the present invention, two characteristics of the actuator itself and the characteristics of the actuator controller are dynamically or statically controlled during execution of various operations including a rising motion from a lying or lying posture. By doing so, it is possible to provide an excellent legged mobile robot capable of realizing a stable and highly efficient operation.

  Other objects, features, and advantages of the present invention will become apparent from more detailed description based on embodiments of the present invention described later and the accompanying drawings.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

A. From the front and rear of each how the legged mobile robot is upright is subjected to an "humanoid" or "human-type" of the present invention the mechanical configuration diagram 1 and 2 of the legged mobile robot It shows a view. As shown in the figure, the legged mobile robot includes a torso, a head, left and right upper limbs, and left and right lower limbs that perform legged movement. For example, a control unit ( (Not shown) is designed to control the overall operation of the aircraft.

  Each of the left and right lower limbs is composed of a thigh, a knee joint, a shin, an ankle, and a foot, and is connected by a hip joint at the substantially lower end of the trunk. The left and right upper limbs are composed of an upper arm, an elbow joint, and a forearm, and are connected to the left and right side edges above the trunk by shoulder joints. The head is connected to the substantially uppermost center of the trunk by a neck joint.

  The control unit is equipped with a controller (main control unit) that processes the external inputs from each joint actuator and sensors (described later) that constitute this legged mobile robot, and a power supply circuit and other peripheral devices. It is a housing. In addition, the control unit may include a communication interface and a communication device for remote operation. The drive control of the joint actuator mentioned here includes control of the servo gain of the actuator and viscosity control in addition to the angular position control, angular velocity control, and angular acceleration of the joint angle.

  The legged mobile robot configured as described above can realize bipedal walking by whole body cooperative operation control by the control unit. Such biped walking is generally performed by repeating a walking cycle divided into the following operation periods. That is,

(1) Single leg support period with left leg lifted right leg (2) Both leg support period with right leg grounded (3) Single leg support period with right leg lifted with left leg (4) Both legs with left leg grounded Support period

  The walking control in the legged mobile robot is realized by planning the target trajectory of the lower limb in advance and correcting the planned trajectory in each of the above periods. That is, in the both-leg support period, the correction of the lower limb trajectory is stopped, and the waist height is corrected at a constant value using the total correction amount with respect to the planned trajectory. In the single leg support period, a corrected trajectory is generated so that the relative positional relationship between the corrected ankle and waist of the leg is returned to the planned trajectory.

  In general, ZMP is used as a norm for determining the stability of walking for posture stability control of the aircraft, including correction of walking motion trajectory. That is, the calculation is performed by interpolation calculation using a fifth-order polynomial so that the position, velocity, and acceleration for reducing the deviation from ZMP are continuous. The standard for discriminating the stability by ZMP is the principle of D'Alembert that gravity and inertia force from the walking system to the road surface, and these moments balance with the floor reaction force and the floor reaction force moment as a reaction from the road surface to the walking system. based on. As a result of dynamic reasoning, there is a ZMP in which the pitch axis and roll axis moments are zero inside the support polygon formed by the sole contact point and the road surface (described above).

  FIG. 3 schematically shows an example of the configuration of the joint degrees of freedom that the legged mobile robot has. As shown in the figure, a legged mobile robot is a body that connects an upper limb including two arms and a head 1, a lower limb comprising two legs that realize a moving operation, and an upper limb and a lower limb. It is a structure provided with a plurality of limbs composed of a trunk.

  The neck joint (Neck) that supports the head has four degrees of freedom: a neck joint yaw axis 1, first and second neck joint pitch axes 2 </ b> A and 2 </ b> B, and a neck joint roll axis 3.

  Each arm portion has a degree of freedom as a shoulder joint pitch axis 4 at the shoulder, a shoulder joint roll axis 5, an upper arm yaw axis 6, an elbow joint pitch axis 7 at the elbow, and a wrist ( Wrist) is composed of a wrist joint yaw axis 8 and a hand portion. The hand part is actually a multi-joint / multi-degree-of-freedom structure including a plurality of fingers.

  The trunk (Trunk) has two degrees of freedom: a trunk pitch axis 9 and a trunk roll axis 10.

  In addition, each leg constituting the lower limb includes a hip joint yaw axis 11 at the hip joint (Hip), a hip joint pitch axis 12, a hip joint roll axis 13, a knee joint pitch axis 14 at the knee (Knee), and an ankle (Ankle). ), An ankle joint pitch axis 15, an ankle joint roll axis 16, and a foot.

  A portion near the waist corresponding to the pelvis that connects the left and right hip joints is called a “base”. Since the mass operation amount is large, the base body is an important control target point in the posture stability control of the legged mobile robot.

B. Control System Configuration of Legged Mobile Robot FIG. 4 schematically shows a control system configuration of the legged mobile robot 100. As shown in the figure, the legged mobile robot 100 includes each of the mechanism units 30, 40, 50R / L, 60R / L representing human limbs, and adaptive control for realizing a cooperative operation between the mechanism units. (Where R and L are suffixes indicating right and left, respectively, and so on).

  The entire operation of the legged mobile robot 100 is controlled by the control unit 80 in an integrated manner. The control unit 80 exchanges data and commands between a main control unit 81 configured by main circuit components (not shown) such as a CPU (Central Processing Unit) and a memory, and each component of the power supply circuit and the robot 100. The peripheral circuit 82 includes an interface (none of which is shown).

  In realizing the present invention, the installation location of the control unit 80 is not particularly limited. In the example shown in FIG. 4, it is mounted on the trunk unit 40, but may be mounted on the head unit 30. Alternatively, the control unit 80 may be provided outside the legged mobile robot 100 so as to communicate with the body of the legged mobile robot 100 by wire or wirelessly.

Each degree of freedom of joint in the legged mobile robot 100 shown in FIG. 3 is realized by a motor or other type of actuator corresponding to each. That is, the head unit 30 includes a neck joint yaw axis actuator A ₁ representing the neck joint yaw axis 1, the first and second neck joint pitch axes 2 A and 2 B, and the neck joint roll axis 3. Second neck joint pitch axis actuators A _2A and A _2B and neck joint roll axis actuators A ₃ are respectively disposed.

The trunk unit 40 is provided with a trunk pitch axis actuator A ₉ and a trunk roll axis actuator A ₁₀ that represent the trunk pitch axis ₉ and the trunk roll axis ₁₀ .

Further, the arm unit 50R / L is subdivided into an upper arm unit 51R / L, an elbow joint unit 52R / L, and a forearm unit 53R / L, but a shoulder joint pitch axis 4, a shoulder joint roll axis 5, an upper arm Shoulder joint pitch axis actuator A ₄ , shoulder joint roll axis actuator A ₅ , upper arm yaw axis actuator A ₆ , elbow joint pitch axis expressing the degrees of freedom of yaw axis 6, elbow joint pitch axis 7, and wrist joint yaw axis 8 An actuator A ₇ and a wrist joint yaw axis actuator A ₈ are provided.

The leg unit 60R / L is subdivided into a thigh unit 61R / L, a knee unit 62R / L, and a shin unit 63R / L, but the hip joint yaw axis 11, hip joint pitch axis 12, hip joint Hip joint yaw axis actuator A ₁₁ expressing the degree of freedom of each of the roll axis 13, knee joint pitch axis 14, ankle joint pitch axis 15, and ankle joint roll axis 16, hip joint pitch axis actuator A ₁₂ , hip roll axis actuator A ₁₃ , A knee joint pitch axis actuator A ₁₄ , an ankle joint pitch axis actuator A ₁₅ , and an ankle joint roll axis actuator A ₁₆ are provided.

The actuators A ₁ , A ₂ , A ₃ ... Used for each joint are more preferably composed of small AC servo actuators of a gear direct connection type and a servo control system mounted on a motor unit in a single chip. can do. This type of AC servo actuator is disclosed in, for example, Japanese Patent Application Laid-Open No. 2000-299970 (Japanese Patent Application No. 11-33386) already assigned to the present applicant.

  For each mechanism unit such as the head unit 30, trunk unit 40, arm unit 50, and leg unit 60, sub-control units 35, 45, 55, and 65 for actuator drive control are disposed.

  An acceleration sensor 95 and a posture sensor 96 are disposed on the trunk 40 of the body. The acceleration sensor 95 is disposed in the X, Y, and Z axial directions. By locating the acceleration sensor 95 on the waist of the airframe, setting the waist, that is, the base body, which is a part with a large amount of mass operation as the control target point, directly measuring the posture and acceleration at that position, the posture based on ZMP Stable control can be performed.

  In addition, ground check sensors 91 and 92 and acceleration sensors 93 and 94 are disposed on the legs 60R and 60L, respectively. The ground contact confirmation sensors 91 and 92 are configured by, for example, mounting a pressure sensor on the sole, and can detect whether the sole has landed based on the presence or absence of a floor reaction force. The acceleration sensors 93 and 94 are arranged at least in the X and Y axial directions. By disposing the acceleration sensors 93 and 94 on the left and right feet, the ZMP equation can be directly assembled with the feet closest to the ZMP position.

  When the acceleration sensor is placed only on the waist where the mass manipulated variable is large, only the waist, that is, the base, is the direct control target point, and the foot state is relative based on the calculation result of this control target point. Therefore, the following condition must be satisfied between the foot and the road surface.

(1) The road surface does not move no matter what force or torque is applied.
(2) The friction coefficient with respect to translation on the road surface is sufficiently large, and no slip occurs.

  On the other hand, in the present embodiment, a reaction force sensor system (such as a floor reaction force sensor) that directly applies a force to the ZMP is provided on a foot that is a contact portion with the road surface, and local coordinates used for control and the coordinates thereof An acceleration sensor for directly measuring is provided. As a result, the ZMP balance equation can be directly assembled with the foot portion closest to the ZMP position, and more rigorous posture stabilization control can be realized at high speed without depending on the preconditions described above. As a result, the fuselage can be used on gravel where the road surface moves when force or torque is applied, on carpets with long bristle feet, or in residential tiles where sliding friction cannot be secured sufficiently. Can guarantee stable walking (movement).

  The main control unit 80 can dynamically correct the control target in response to the outputs of the sensors 91 to 96. More specifically, whole body motion in which each of the sub-control units 35, 45, 55, and 65 is adaptively controlled and the upper limbs, trunk, and lower limbs of the legged mobile robot 100 are cooperatively driven. Realize the pattern.

The whole body movement on the body of the robot 100 sets the foot movement, the ZMP trajectory, the trunk movement, the upper limb movement, the waist height, and the like, and commands for instructing the movement in accordance with these setting contents. Forward to the units 35, 45, 55, 65. Then, in each of the sub-control section 35, 45 ... interprets the command received from the main control unit 81 outputs a drive control signal to the actuators _{A 1, A 2, A 3} .... ZMP is a point on the floor where the moment caused by the floor reaction force during walking is zero, and the “ZMP trajectory” mentioned here means, for example, a trajectory in which the ZMP moves during the walking operation period of the robot 100. To do.

C. Control of actuator characteristics
C-1. Actuation speed of the actuator, mechanically passive legged mobile robot body can be regarded as a multi-link structure in which a plurality of joint axes having approximately parallel joint degrees of freedom are connected in the length direction. In the course of each leg type motion such as walking motion, falling motion, and standing motion from the floor posture, the link state between the landing part of the multi-link structure and the floor surface is between the open link state and the closed link state. To switch several times.

  Japanese Patent Application No. 2001-233691 already assigned to the present applicant discloses a legged mobile robot that performs high-speed repetitive operations between a closed link state and an open link state with respect to the outside world and work objects. Yes. That is, in a robot having limbs composed of one or more rotary joints (which may have two or more degrees of freedom per joint), the minimum number of passive degrees of freedom necessary to remove the dynamic closure error for each limb. (Decelerator backlash, etc.) and manage the range of movement of each limb appropriately. Even if the actuator that drives the joint does not have a means for acquiring torque information, a high-speed switching operation between the closed link state and the open link state is stably realized. Such a high-speed switching operation between the closed link state and the open link state is performed by placing a geared motor with a small backlash amount in a part close to the waist reference coordinates in a biped walking robot, and back in a part close to the hand / tip. This can be realized by arranging geared motors with a large amount of rush and obtaining optimum characteristics, so that the robot design can be optimized.

  As a second method for optimizing the robot, the position error deviation amount is controlled by arbitrarily adjusting the open loop gain of the position servo compensator in each joint axis actuator. In other words, when the backlash amount is uniform, the servo deviation due to the servo gain is considered as the backlash amount, and by controlling it, a passive degree of freedom for removing the dynamic closing error can be obtained. .

  In the present embodiment, the latter optimization method is further expanded to adjust not only the proportional gain of the servo controller but also the phase compensation element at each joint part.

  FIG. 5 shows the configuration of the servo controller of the actuator. As shown in the figure, the servo controller has two control elements, a proportional gain K for series compensation and a phase compensation element C (s), and adjusts not only the proportional gain but also the phase compensation element at each joint part. FIG. 6 shows the frequency characteristics of the gain and phase of the transfer function expression model for the motor and reducer shown in FIG.

Here, the phase compensation element is expressed by the following equation. However, n and m are arbitrary natural numbers, and a _i and b _i are arbitrary real numbers. When state variables are expressed, they correspond to feedback gains. S is a Laplace operator.

  Moreover, the transfer function expression model G (s) of the motor and the speed reducer is expressed by the following expression. Where K is the motor gain, J is the moment of inertia of the motor, and D is the viscous resistance coefficient of the motor.

  First, in the servo controller shown in FIG. 5, as an example of designing the phase compensation type control, the phase compensation band is arbitrarily selected (the phase compensation amount is constant and the frequency band is arbitrarily selected) with reference to FIG. While explaining. In the figure,

(1) C (s) -1: A gain amplification of about +5.6 dB and a phase advance of about +18 deg are given in a band of 1.0 to 100 Hz.
(2) C (s) -2: A gain amplification of about +5.6 dB and a phase advance of about +18 deg are given in a band of 0.1 to 10 Hz.
(3) C (s) -3: gain amplification of about +5.6 dB and phase advance of about +18 deg in a band of 10 to 1 kHz.

  As described above, the frequency characteristics of the actuator can be freely set by arbitrarily selecting the frequency band to which the phase compensation is performed. Therefore, the joint axis of the robot constituted by such an actuator can dynamically adjust the frequency characteristics according to the posture of the airframe and the situation of the operation.

  In the example shown in FIG. 7, an example of phase lead compensation is shown. However, in the case of phase delay compensation, any phase delay amount can be set in any frequency band.

  Next, in the servo controller shown in FIG. 5, as an example of designing the phase compensation type control, the amount of phase compensation is arbitrarily selected (the frequency compensation is constant and the phase compensation amount is arbitrarily selected). The description will be given with reference. In the figure,

(4) C (s) -4: Gain amplification of about +3.5 dB and a phase advance of about +12 deg in a band of 4.0 to 70 Hz.
(5) C (s) -5: A gain amplification of about +5.6 dB and a phase advance of about +18 deg are given in the band of 2.0 to 70 Hz.
(6) C (s) -6: A gain amplification of about +6.5 dB and a phase advance of about +21 deg are given in the band of 1.0 to 70 Hz.

  Thus, the frequency characteristic of the actuator can be freely set by arbitrarily selecting the amount of phase compensation. Therefore, the joint axis of the robot constituted by such an actuator can dynamically adjust the frequency characteristics according to the posture of the airframe and the situation of the operation.

  In the example shown in FIG. 8, an example of phase lead compensation is shown. However, in the case of phase delay compensation, any phase delay amount can be set in any frequency band.

  Next, a design example of a controller that changes the magnitude of the series compensation gain indicated by K in the servo controller shown in FIG. 5 will be described with reference to FIG. This figure corresponds to the fact that K is raised and lowered by ± 3 dB in FIG. As shown in the figure, the magnitude of the series compensation gain can be arbitrarily set.

  In order to apply the contents shown in FIGS. 7 to 9 to the actuator for driving the joint axis of the robot, a communication protocol for dynamically or statically changing the parameters constituting these controllers is implemented. Thereby, various characteristics can be given to each joint axis of the robot.

  Next, the characteristics of the actuator when the servo controller for the actuator having these characteristics is mounted will be described.

  FIG. 10 shows an open loop characteristic when the servo controller of the actuator is mounted so as to arbitrarily select the frequency band with a constant phase compensation amount as shown in FIG.

(1) C (s) -1: Gives a gain amplification of about +5.6 dB and a phase advance of about +18 deg in a band of 1.0 to 100 Hz. As a result, the gain is increased overall, so that positioning accuracy and followability are improved, but energy loss is likely to occur. Moreover, it may become unstable when the load increases.
(2) C (s) -2: Gain amplification of about +5.6 dB and phase advance of about +18 deg in a band of 0.1 to 10 Hz. In this case, it has an intermediate characteristic between C (s) -1 and C (s) -2.
(3) C (s) -3: Gives a gain amplification of about +5.6 dB and a phase advance of about +18 deg in a band of 10 to 1 kHz. In this case, phase lead compensation is performed only in the high frequency range, so that the effect is not so much seen during slow operation, but it is effective for fast operation such as running, flying, and dancing.

  As described above, the frequency characteristics of the actuator can be freely set by arbitrarily selecting the frequency band to which the phase compensation is performed. Therefore, the joint axis of the robot constituted by such an actuator can dynamically adjust the frequency characteristics according to the posture of the airframe and the situation of the operation.

  Further, FIG. 11 shows a state in which the control of the series compensation gain is further adopted in Example C (s) -3 in which the phase lead compensation is performed only in the high frequency region shown in FIG. In this case, as in the example shown in FIG. 5, the gain increases and decreases in the same phase.

  In the example shown in FIG. 10, the phase compensation example C (s) -3 is not very effective during a slow operation, but as shown in FIG. 11, by increasing the gain in the low frequency band, The control deviation can be reduced. As a result, it is possible to respond to the command value with a small delay even during slow operation.

  To summarize these, first, with respect to the open-loop characteristics of the actuator position control system, as shown in FIG. 12, by setting the characteristics so as to increase the overall gain and reduce the phase advance amount in the high range, It is possible to harden the parts and joints that require positional accuracy, such as support legs, and eliminate compliance.

  In contrast, as shown in FIG. 13, the open loop characteristics of the actuator position control system are set such that the gain is low in the low range and the phase advance amount is large in the middle and high ranges. Thus, it is possible to obtain characteristics suitable for a joint site that requires a higher-speed response than the position accuracy, and when a joint requires compliance.

  As described above, the mechanism for adjusting not only the proportional gain of the servo controller but also the phase compensation element in each part of the joint in the servo controller of the actuator has been described. Thus, in order to realize a stable and highly efficient operation, it is possible to increase or decrease the force locally and increase or decrease the compliance (mechanical passivity) of each joint part.

  For example, when capturing the motion of each joint axis as a position control system, it is better to use a high gain and high bandwidth servo controller to control the control deviation to be small, but when capturing as a dynamic model In consideration of the action of potential energy and kinetic energy, it is preferable to lower the gain or raise and lower the frequency band for phase compensation.

C-2. Viscous resistance of actuator / motor In addition to the characteristics of actuator operating speed and mechanical passivity during operation as described in the above section C-1, a method of variably controlling the viscous resistance of the actuator can be adopted. .

  For example, a motor of a type that generates rotational torque by controlling a current supplied to a coil to form a predetermined magnetic flux distribution generally includes a first transistor switch group that connects a coil terminal to a power supply voltage, and a coil A switching operation circuit composed of a second transistor / switch group that grounds a terminal is driven by PWM control, thereby controlling a coil current to obtain a desired torque, rotational position, rotational speed, or the like.

  Here, at the timing when the motor coil is in the open state during the non-energized period, the current (strictly charge) energized to the motor coil is lost, resulting in a torque loss. Further, it is easily affected by torque unevenness due to cogging.

  In such a case, even when the motor / coil is not energized, the current (electrically charged) energized to the motor / coil cannot be removed by forming a short-circuit state in which the coil is not open. Can be. At this time, a counter electromotive force is generated in the motor coil due to the magnetic flux density from the permanent magnet side. Since the counter electromotive force causes a force in the direction opposite to the rotation direction of the motor, a viscous resistance against rotation by an external force can be created, and an effect similar to a brake can be obtained. By such viscous resistance to the motor, there is no torque loss and the influence of torque unevenness due to cogging is reduced.

  On the other hand, when a short circuit state of such a coil is formed when the motor is de-energized, as described above, a kind of viscous resistance can be given to the motor, but when such a motor is used for a robot, Due to the influence of the brake due to the coil short, there is a problem that compliance (mechanical passivity) is lost.

  Therefore, by adjusting the ratio of the coil open state and short-circuit state period when the motor coil is not energized according to the desired mechanical characteristics, the motor coil at the timing when the motor coil is opened Compliance (mechanically passive) due to torque loss due to loss of energized current (strictly charge), torque unevenness due to cogging, and brake effect due to coil short when motor / coil is not energized The problem of disappearing) can be solved together.

  Here, the ratio of energization and de-energization of the motor / coil can be realized by PWM control, but the ratio of the open / short-circuit period of the coil in the de-energization of the motor / coil is also the same. It can be realized using PWM control.

  FIG. 14 shows a configuration example of an equivalent circuit of a current control circuit for supplying coil current in a DC motor to which a coil current control mechanism is applied.

The current control circuit shown in the figure has a full-bridge configuration, and a circuit in which a pnp transistor A ′ and an npn transistor A are connected in a forward direction, and a pnp transistor B ′ and an npn transistor B are sequentially connected. The direction-connected circuits are connected in parallel between the power supply voltage _Vcc and the ground GND, and the intermediate points of the transistors A ′ and A and the intermediate points of the transistors B ′ and B are connected by a single-phase coil of the stator.

  When the transistors A ′ and B are turned on and the transistors A and B ′ are turned off, the current Im flows in the motor coil in the direction indicated by the arrow. Further, by turning off the transistors A ′ and B, the coil is opened and the current Im does not flow. Further, by turning off the transistors A ′ and B and turning on the transistors A ′ and B ′, the motor coil is short-circuited.

  The PWM control logic circuit generates a current command to the coil based on a current axis current command (or torque command) from a central control unit (not shown), and performs switching control of each transistor by the PWM method based on the current command. . That is, the energizing period in which the transistors A ′ and B are turned on and the transistors A and B ′ are turned off to flow the coil current Im and the non-energizing period in which the transistors A ′ and B are turned off and the coil is de-energized are alternated. To generate.

  In the present embodiment, an additional logic circuit for switching the control signals for controlling the on / off operation of the transistors A and A ′ and the arrangements B and B ′ output from the PWM control logic circuit by the additional logic is provided.

FIG. 15 shows a specific circuit configuration of the additional logic circuit. The additional logic circuit controls the on / off operation of the signals A ₀ and A ₀ ′ and the rows B ₀ and B ₀ ′ output from the PWM control logic circuit based on the BRAKE_PWM control signal output from the PWM control logic circuit. The control logic is switched by additional logic. As a result, the coil is switched between the open state and the short-circuit state when the motor / coil is not energized.

PWM control logic circuit and the transistors A 'signal A ₀ for control' from the logical product of the transistors B ₀ 'signal B ₀ for control', signal B ₀ of the signal A ₀ and the transistor B control for controlling the transistor A Is obtained, and the logical product of these logical operation values is inverted and logically ORed with the inverted signal of the BRAKE_PWM control signal. A logical product of the result of the logical sum with the original transistor control signals is the final transistor control signal.

When a high level is input to the BRAKE_PWM control signal, the additional logic circuit switches the transistor control signal so that the coil is short-circuited when the coil is not energized. When the coil is not normally energized, the PWM control logic circuit outputs a transistor control signal that makes the control signals A ₀ ′ and B ₀ ′ high and A ₀ and B ₀ low. On the other hand, when a high level BRAKE_PWM control signal is input, the additional logic circuit turns A ₁ ′ and B ₁ ′ in the high state to low to form a short circuit state of the coil.

  On the other hand, when the BRAKE_PWM control signal is in the low state, the additional logic circuit outputs the transistor control signal from the PWM control logic circuit as it is when the coil is not energized, so that the coil is in the open state when deenergized.

  FIG. 16 shows the output characteristics of each transistor control signal of the additional logic circuit together with the coil current waveform characteristics and torque output characteristics when a BRAKE_PWM control signal having a predetermined duty ratio is input by PWM control. Yes.

  When the coil is short-circuited when the coil is not energized, the time until the coil current returns to zero becomes longer due to the transient response, but when the coil is opened, the time becomes shorter. The transient response characteristics when the coil is not energized are a mixture of these characteristics according to the duty ratio of the BRAKE_PWM control signal.

  Therefore, as shown in the figure, when the switching operation of coil energization and coil short circuit is repeated, the next energization is started before the coil current returns to zero when the coil is not energized. At this time, the maximum current of the coil gradually increases every time the coil is energized and de-energized, and the increasing tendency is almost proportional to the duty ratio, that is, the ratio at which the BRAKE_PWM control signal becomes high level. Similarly, the effective value of the coil current gradually increases as shown in the figure, but the increasing tendency is substantially proportional to the duty ratio, that is, the ratio at which the BRAKE_PWM control signal becomes high level.

  Further, since the motor output torque T is a value obtained by multiplying the coil current by the motor torque constant Kt (T = Kt · I), as can be seen from FIG. As the coil current increases, the effective value of the motor torque increases. Therefore, when the motor coil is not energized, a short-circuit state occurs, so that the current (strictly charge) energized to the motor coil is not lost and torque loss is eliminated. Further, it is less susceptible to torque unevenness due to cogging.

  The upward trend when the coil energization and the non-energization are repeated is substantially proportional to the duty ratio of the BRAKE_PWM control signal, that is, the ratio at which the control signal becomes high level. The characteristic that the output of the motor torque increases corresponds to the viscosity coefficient of the motor. In other words, the viscous resistance of the motor can be dynamically controlled by the duty ratio of the BRAKE_PWM control signal.

  When such a short circuit state of the coil is formed when the motor is not energized, as described above, a kind of viscous resistance can be given to the motor. On the other hand, when such a motor is used for a robot, there is a problem that compliance (mechanical passivity) is lost due to the influence of a brake caused by a coil short circuit.

  Therefore, the PWM control logic circuit controls the ratio of the period between the open state of the coil and the short-circuit state in the non-energized state of the motor coil by performing PWM control on the BRAKE_PWM control signal input to the additional logic circuit.

  When PWM control is performed for the open and shorted periods of the coil when the motor / coil is not energized, the coil current characteristics are the transient response characteristics of the coil current and the coil when the coil is opened when the coil is not energized. The characteristics of the transient response characteristics of the coil current when the is short-circuited are mixed according to the duty ratio.

  In this way, the duty ratio of the BRAKE_PWM control signal supplied from the PWM control logic circuit to the additional logic circuit is PWM controlled, so that the ratio of the open state and the shorted state of the coil when the motor / coil is not energized can be set to a desired value. It can be adjusted according to the mechanical properties.

  Therefore, there is a problem of torque loss due to loss of current (electrically, electric charge) applied to the motor coil at the timing when the motor coil is in an open state, torque unevenness due to cogging, and deenergization of the motor coil. The problem of loss of compliance (mechanical passivity) due to the effect of braking due to a coil short at the time can be solved together.

  Further, as described above, the viscous resistance of the motor can be dynamically controlled by the duty ratio of the BRAKE_PWM control signal. The control relationship is shown in FIG. In the figure, the viscous resistance is represented by the product of the viscosity coefficient [mN−m · s / rad] and the rotational angular velocity [rad / s] during operation.

  The area indicated by A in FIG. 17 corresponds to the maximum viscosity coefficient in terms of motor characteristics, and is 0.9 mN-m · s / rad in the illustrated example. When the actuator characteristics are set in this region, the joint viscosity increases. As a result, although compliance cannot be obtained, it is possible to realize control characteristics that are robust against disturbances such as external vibrations.

  On the other hand, the region indicated by B in FIG. 17 corresponds to a viscosity coefficient that is 1/3 or less of the maximum value on the motor characteristics, and is 0.15 mN-m · s / rad in the illustrated example. When the actuator characteristics are set in this region, the joint viscosity becomes small. As a result, it becomes weak against disturbance, but mechanical passivity (compliance) can be obtained.

  The region B for obtaining the compliance may basically be equal to or less than the maximum value on the motor characteristics, but as shown in the drawing, the inclination around 0.3 to 0.8 mN-m · s / rad is Steep portions are easily affected by environmental changes such as temperature, making control difficult. For this reason, as described above, it is considered appropriate to set the region where the inclination is gentle at a third or less of the maximum value on the motor characteristics as the mechanical passive region. Has been proved by experiments.

  In the above description, a DC motor has been described as an example, but the same applies to a three-phase motor and other types of motors that generate rotational torque by forming a predetermined magnetic flux distribution by controlling the current supplied to other coils. In addition, a desired viscous resistance of the motor can be obtained by intermittently switching the motor coil during non-energization between an open state and a short-circuit state.

C-3. Application to Legged Mobile Robot Next, a bipedal legged mobile robot in which the characteristics control mechanism of the actuator servo controller and the actuator characteristic control mechanism according to this embodiment is applied to each joint part will be described.

  As described above, in the servo controller of the actuator, by adjusting the proportional gain and the phase compensation element, the positioning accuracy, mechanical passivity (compliance), and operation speed required for each part of the robot joint are arbitrarily set. be able to. In addition, when the coil of the actuator / motor is not energized, the coil is intermittently switched to a short circuit state or an open state, thereby adjusting the viscous resistance of the motor and changing the robustness against disturbances such as vibration.

  Furthermore, by combining the gain and phase compensation control in the servo controller of these actuators with the control of the viscous resistance of the actuator and motor, the frequency characteristics of the actuator that can be applied to the parts where positioning accuracy is important, or high-speed response Thus, it is possible to obtain the frequency characteristics of the actuator that can be applied to a portion where compliance is important.

  The frequency characteristics of the actuator that can be applied to a portion where positioning accuracy is important are as shown in FIG. In this case, the proportional gain of the servo controller is increased to increase the gain of the entire system so that the gain can be obtained up to the low frequency band. Further, as shown in the figure, the frequency characteristic is such that the amount of phase advance is reduced in the high frequency range, so that stability is ensured although it does not contribute much to high-speed response. In addition, the viscous resistance of the motor is increased so that it is robust against disturbances such as vibration. In short, the characteristics shown in the figure are robust to disturbances such as vibrations with priority given to positioning accuracy.

  Further, the frequency characteristics of the actuator that can be applied to a portion where high-speed response and compliance are important are as shown in FIG. In this case, by reducing the proportional gain and reducing the gain of the entire system, the gain in the low frequency band is reduced, and mechanical passivity (compliance) is easily obtained. Further, as shown in the figure, the frequency characteristic is set so that the phase advance amount becomes large in the middle and high range so as to obtain high-speed response. In addition, the viscous resistance of the motor is reduced to facilitate obtaining mechanical passivity (compliance). In short, the characteristics shown in the figure are characteristics giving priority to mechanical passivity (compliance) and high-speed response.

  The joint freedom degree of the legged mobile robot shown in FIGS. 1 to 3 is realized by an actuator including the servo controller described above. A basic control example of the gain / phase compensation characteristics of the actuator used in each joint part will be described in detail below.

(1) Characteristics of the actuator applied to the neck portion In the neck portion, the proportional gain is set high in order to prioritize positioning accuracy. Further, the phase advance amount is set to be small so as not to impair the stability of the increased proportional gain while maintaining the operation speed. Further, in order to obtain robustness against vibration disturbance generated during the operation of the portion below the body, the joint viscous resistance is set large.

(2) Characteristics of the actuator applied to the shoulder and elbow parts When performing continuous motions such as walking and dancing, the actuator is given characteristics that make it more mechanically passive than the positioning characteristics. To make the motion passive, reduce the viscous resistance of the joint. In addition, the proportional gain is set low in order to make the operation passive and reduce energy consumption. In order to increase the operation speed, the phase advance amount is set large in the middle and high range. Some operations only reciprocate like a pendulum. In that case, the mechanical resistance (compliance) is obtained by minimizing the viscous resistance and the proportional gain of the joint, and the mechanical energy is easily used for the operation.

  On the other hand, when an operation using force such as pushing or pulling an object is performed, control is performed so that the positioning accuracy priority characteristic and the mechanical passive characteristic are dynamically switched according to the load torque value. To generate more force with respect to the load torque value, increase the proportional gain and increase the joint viscous resistance.

  In addition, when performing an operation that makes the load torque value follow a constant load, in addition to the adjustment by the position command value from the upper level, a proportional gain according to the load torque detected by the actuator internal torque sensor To reduce the viscous resistance of the joints to obtain mechanical passivity (compliance).

(3) Characteristics of the actuator applied to the trunk part In order to obtain robustness against vibration disturbance due to own movement, the viscous resistance of the joint is increased. Alternatively, the proportional gain is set high in order to prioritize positioning accuracy. Alternatively, the phase advance amount is set to be small so as not to impair the stability of increasing the proportional gain while maintaining the operation speed.

(4) Characteristics of the actuator applied to the hip joint portion In order to obtain robustness against vibration disturbance due to its own movement, the viscous resistance of the joint is increased. Alternatively, the proportional gain is set high in order to prioritize positioning accuracy. Alternatively, the phase advance amount is set to be small so as not to impair the stability of increasing the proportional gain while maintaining the operation speed.

(5) Characteristics of the actuator applied to the knee portion Control is made so that the mechanical passivity is higher than the positioning accuracy at the time of the free leg and at the moment of landing. To make the motion passive, reduce the viscous resistance of the joint. In addition, the proportional gain is set low in order to make the operation passive and reduce energy consumption. In order to increase the operation speed, the phase advance amount is set large in the middle and high range.

  On the other hand, at the time of the support leg, control is performed so that the positioning accuracy is higher than the mechanical passivity. In order to obtain robustness against vibration disturbance caused by one's own movement, the viscous resistance of the joint is increased. Alternatively, the proportional gain is set high in order to prioritize positioning accuracy. Alternatively, the phase advance amount is set to be small so as not to impair the stability of increasing the proportional gain while maintaining the operation speed.

(6) Characteristics of the actuator applied to the ankle portion Control is made so that the mechanical passivity is higher than the positioning accuracy at the time of the free leg and at the moment of landing. In order to mitigate the impact caused by the landing of the ankle part, the joint viscosity should be set small to obtain mechanical passivity (compliance). In addition, in order to mitigate the impact caused by the landing of the ankle part, the proportional gain is set low to obtain mechanical passivity (compliance). In order to increase the operation speed, the phase advance amount is set large in the middle and high range.

  On the other hand, at the time of the supporting leg, the joint resistance resistance is increased in order to increase the torque generated at the ankle portion and to obtain robustness against vibration disturbance caused by the movement of itself. Further, in order to improve the positioning accuracy of the ankle portion, the proportional gain is set high. Further, the phase advance amount is set to be small so as not to impair the stability of the increased proportional gain while maintaining the operation speed.

  Here, the effect of switching the characteristics of the joint actuator in accordance with the operation stage of the robot will be described taking a walking operation as an example.

  FIG. 18 shows a state where the legged mobile robot performs a walking motion for each stage. In the example shown in the figure, the walking motion is divided into seven stages of A to G, and when the walking motion is continued, the gait is repeatedly executed in this order.

(1) Shoulder-arm portion During the walking motion of the robot indicated by A to G, the arm is swung to compensate for the rotational moment around the yaw axis of the reference coordinates of the robot. The motion of swinging the arm is a periodic pendulum motion around the shoulder pitch axis.

  In such a case, the potential energy is obtained because the arm is lifted by the torque applied at the initial stage of the operation. This potential energy becomes kinetic energy according to the energy conservation law when the arm is swung down. That is, the energy conversion is repeated in which the potential energy generated by the torque applied in the initial stage of the operation is converted into kinetic energy according to the principle that the pendulum descends.

  If such a property is actively used, mechanical energy can be added to the torque (ie, energy consumption) generated for the robot to follow the position control, so that the energy consumption of the entire robot can be saved. it can.

  Specifically, when the kinetic energy of the arm portion is maximized, the main portion of the arm (for example, the shoulder pitch axis, the elbow pitch axis, etc.) instantaneously generates torque. If the joint viscous resistance is large at this time, the loss during operation increases, which is not good. Further, even if the viscous resistance is small, the loss during operation does not become zero, so it is necessary to instantaneously generate torque in order to supplement the loss.

  In order to realize these with one servo control, a system in which the gain in the low frequency band is low due to the open loop characteristics and the gain is increased by increasing the phase compensation amount in the middle / high range is suitable. In addition to this, it is preferable to reduce energy loss during operation by setting the viscosity coefficient of the motor to a minimum value that can be realized by controlling the viscous resistance.

  The frequency characteristics of the actuator shown in FIG. 13 realize such servo control and motor viscous resistance control. Therefore, the actuator of the joint part related to the movement of the arm during the walking movement may be set to the characteristics shown in FIG.

(2) Leg part During the walking motion of the robot shown by A to G, a gait of the leg is generated in accordance with the posture control of the ZMP standard. This movement of the legs is repeated between the both-leg support period and the one-leg support period in which one leg is the support leg and the other leg is the free leg.

  Regardless of the support leg or the free leg, the roll axis direction follows the ZMP trajectory, so that high positioning accuracy of one servo control system is required. That is, in the open loop characteristic, a high gain is required in the entire frequency band.

  Since the pitch axis of each joint of the support leg follows the ZMP trajectory, high positioning accuracy is required. At the same time, it is required to be robust against disturbances such as vibration. Therefore, in order to satisfy these two requirements, the pitch axis of each joint of the support leg is set to a large proportional gain of the servo controller shown in FIG. Characteristics that can gain gain are suitable. It is also suitable to set the motor's viscous resistance large.

  On the other hand, the knee pitch axis and the ankle pitch axis at the time of the free leg perform the swing-up and swing-down operations alternately like the arm portion. Therefore, it is preferable that the joint viscous resistance is small. At the same time, in the open loop characteristic, the characteristic shown in FIG. 13 is suitable, in which the gain is low in the low frequency band, and the phase compensation amount is increased in the middle / high range to increase the gain.

  In addition, a high frequency impact disturbance is applied to the ankle pitch shaft joint at the moment of landing. At this time, it is desirable to ensure responsiveness in a high frequency band. At this time, it is desirable that the gain in the low frequency band is low. At the same time, it is desirable that the joint viscosity resistance is small. Therefore, the characteristics shown in FIG. 13 are suitable for the ankle pitch axis joint at the moment of landing.

D. Posture stabilization control of legged mobile robot Next, the legged mobile robot 100 according to the present embodiment performs posture stabilization processing at the time of legged work, that is, execution of whole body coordinated motion including leg, waist, trunk, lower limb motion, etc. The procedure of the posture stabilization process at the time will be described.

  For posture stability control, ZMP is used for posture stability control. In the present embodiment, a portion where the mass operation amount is maximum, for example, a waist or a base body, is set as a local coordinate origin as a control target point on the robot body. Then, a measuring means such as an acceleration sensor is arranged at the control target point, and the posture and acceleration at the position are directly measured to perform posture stability control based on ZMP. Further, by providing an acceleration sensor on the foot which is a contact portion with the road surface, the local coordinates used for the control and the coordinates are directly measured, and the ZMP equation is directly assembled with the foot closest to the ZMP position.

D-1. Introduction of ZMP Equation The legged mobile robot 100 according to the present embodiment is an infinite or continuous mass collection. However, the calculation amount for the stabilization processing is reduced by substituting an approximate model composed of a finite number of discrete mass points. More specifically, the legged mobile robot 100 having the multi-joint degree-of-freedom configuration shown in FIG. 3 is physically replaced with a multi-mass point approximation model as shown in FIG. The approximate model shown is a linear and non-interfering multi-mass point approximate model.

  In FIG. 19, the O-XYZ coordinate system represents the roll, pitch, and yaw axes in the absolute coordinate system, and the O′-X′Y′Z ′ coordinate system represents the roll, pitch, Each axis of yaw is represented. However, the meanings of the parameters in the figure are as follows. It should also be understood that symbols with a dash (') describe a motion coordinate system.

In the multi-mass point model shown in FIG. 19, i is a subscript representing the i-th mass point, m _i is the mass of the i-th mass point, r _i ′ is the position vector of the i-th mass point (however, the motion coordinates) System). The center of gravity of the body of the legged mobile robot 100 according to the present embodiment exists near the waist. That is, the waist is a mass point where the mass manipulated variable is maximum. In FIG. 19, the mass is m _h , and the position vector (however, the motion coordinate system) is r ′ _h (r ′ _hx , r ′ _hy , r ′). _hz ). Further, the position vector (however, the motion coordinate system) of the ZMP of the aircraft is _assumed to be r ′ _zmp (r ′ _zmpx , r ′ _zmpy , r ′ _zmpz ). Each rotation angle (θ _hx , θ _hy , θ _hz ) in the waist information defines the posture of the waist in the legged mobile robot 100, that is, the rotation of the roll, pitch, and yaw axes.

The world coordinate system O-XYZ is an absolute coordinate system and is invariant. In the legged mobile robot 100 according to the present embodiment, acceleration sensors 93, 94, and 96 are arranged on the waist and the legs of both legs, respectively, and the relative position vector r in the world coordinate system with each of the waist and the stance is determined by the output of these sensors. _q is detected directly. On the other hand, in the motion coordinate system, that is, the local coordinate system of the aircraft, OX'Y'Z 'moves with the robot.

The ZMP equation of the airframe describes the balance relationship of each moment applied at the control target point. As shown in FIG. 19 represents the body in a number of mass points m _i, when the these control target points, obtaining the sum of the moments applied at all the control target point m _i Formula is ZMP equation.

  The ZMP equation of the aircraft described in the world coordinate system (O-XYZ) and the local coordinate system (O-X′Y′Z ′) of the aircraft are as follows.

The above equation, the sum of the moments of ZMP around produced by the acceleration component applied at each mass point m _i (radius r _i -r _ZMP), the sum of external force moment M _i applied to each of the mass points m _i, It is described that the sum of moments around ZMP generated by the external force F _k (where the point of action of the _kth external force F _k is s _k ) is balanced.

  This ZMP balance equation includes a total moment compensation amount, that is, a moment error component T. By suppressing this moment error to zero or within a predetermined allowable range, the attitude stability of the aircraft is maintained. In other words, it is the essence of posture stability control using ZMP as a stability criterion to correct the body motion (foot motion and trajectory of each part of the upper body) so that the moment error is zero or below the allowable value. is there.

  In the present embodiment, since the waist and the left and right feet are respectively disposed, the above ZMP balance equation can be derived directly and with high accuracy using the acceleration measurement results at these control target points. it can. As a result, high-speed and strict attitude stability control can be realized.

  In this embodiment, since the acceleration sensors 96, 93, and 94 are provided at the soles of the feet that are in contact with the road surface, the local coordinate system of the real robot with respect to the world coordinate system is set, and the origin thereof is set. Thus, the ZMP balance equation can be directly derived. Furthermore, by locating acceleration sensors at control target points where the mass manipulated variable is large including the waist, the moment amount around the ZMP for each control target point can be derived directly using the acceleration sensor output value. it can.

  Here, since a real robot as a control target is a mobile device, it is difficult to obtain a position vector on the world coordinates at each control target point. As an alternative, the position vector of the control target point on the local coordinates can be obtained by a relatively easy calculation method such as inverse kinematics calculation. Therefore, the actual posture stabilization processing may be performed using the latter ZMP balance equation described in the local coordinate system (O-X′Y′Z ′) of the aircraft.

  Since it is difficult to accurately measure the ZMP trajectory in the world coordinate system with a state detector mounted on the robot, an external measuring instrument fixed to the world coordinate system is generally required. (Walking, etc.) becomes impossible. On the other hand, a ZMP trajectory can be obtained accurately and directly in local coordinates by placing a weight sensor on the grounding portion and measuring the ZMP trajectory. In addition, by disposing the acceleration sensor near the local coordinate origin, it is possible to directly measure information that becomes dominant in high-speed motion. For this reason, in this embodiment, the ZMP balance equation in the local coordinate system is used.

D-2. Whole body cooperative posture stability control FIG. 20 shows, in the form of a flowchart, a processing procedure for generating a body motion capable of stable walking using ZMP as a stability criterion in the legged mobile robot 100. However, in the following description, each joint position and operation of the legged mobile robot 100 are described using a linear / non-interference multi-mass point approximation model as shown in FIG.

  First, exercise is set at a ground contact portion such as a foot (step S1). The foot movement is motion data obtained by connecting two or more poses of the aircraft in time series. The motion data is data created and edited in advance using a motion editing device, for example, and includes joint space information representing the displacement of each joint angle of the foot and Cartesian space information representing the joint position. Composed.

  Next, the ZMP stable region is calculated based on the set motion on the ground contact part such as the foot (step S2). Alternatively, the ZMP stable region is calculated based on the desired trajectory with priority set for each part group (step S14: described later). If the point where the robot contacts the road surface, such as floor motion or handstand motion, is not the sole, the ZMP stable region is calculated based on the support polygon formed by the ground contact point other than the sole and the road surface.

  ZMP is a point at which the moment applied to the aircraft becomes zero (as described above), and basically exists inside the support polygon formed by the ground contact point and the road surface. The ZMP stable region is a region set further inside the support polygon, and the aircraft can be brought into a highly stable state by accommodating the ZMP in the region.

  Then, a ZMP trajectory during the foot movement is set based on the foot movement and the ZMP stable region (step S3). However, when the point where the robot touches the road surface, such as floor motion or handstand motion, is not the sole, the ZMP trajectory is set based on the support polygon formed by the grounding point other than the sole and the road surface.

  In addition, each part of the aircraft is set as a group such as a waist, a trunk, an upper limb, and a head (step S11).

FIG. 21 shows an example in which the body part group is set. In the example shown in the figure, each part group of 1 to 7 parts is set in the order of waist, trunk, right arm, head, left arm, left leg, and right leg. Each part group is composed of a plurality of mass points. The mass point setting method may be either manual input by the designer or automatically generated according to a predetermined rule (for example, a part having a large mass manipulated variable such as a joint actuator is set as the mass point). ) When the number of mass points of the i-th part is n _i , the total mass m _i of the i-th part group (part i) is expressed by the following equation.

  Then, a desired trajectory is set for each part group (step S12). The setting of the desired trajectory for each part group of the airframe is performed offline using, for example, a motion editing device.

  Next, the group setting of each part is adjusted (regrouping) (step S13), and priority is given to these groups (step S14). The priority order mentioned here is the order of input to the processing calculation for the attitude stability control of the aircraft, and is assigned according to, for example, the mass operation amount or the moment operation amount. As a result, a desired trajectory group with priority for each part of the aircraft is completed. At this time, connection conditions for each part (local coordinate connection, world coordinate position fixed connection for a specific part, world coordinate posture connection for a specific part, etc.) are also set. The priority order may be changed at time t.

  In addition to the mass operation amount or the moment operation amount, the priority order for each part is determined with reference to a previously planned action plan. For example, since a trajectory of a grounded foot cannot be corrected when a legged motion such as walking is performed, a lower priority is given to the grounded foot. Also, a hand grabbing an object cannot give a lower priority because it cannot correct the trajectory. Also, when walking in a narrow passage sideways, a lower priority is given because the possibility of a collision with the wall is high if the waist trajectory is corrected.

Further, a mass that can be used for moment compensation is calculated for each part group of the machine body (step S15). In the example shown in FIG. 21, since the right leg is the supporting leg and the ZMP position P _ZMP exists in the right foot, the mass M _i that can be used for moment compensation in each part group is as follows.

In addition to the lumbar part itself, one part, that is, the lumbar part, can use the supporting trunk, right arm part, head part, and left arm part for moment compensation. In addition, the two parts, that is, the trunk part, can use the supporting right arm part, head part, and left arm part for moment compensation in addition to the trunk part itself. Also, 3-6 parts, that is, the right arm part, the head part, the left arm part, and the left leg part as a free leg have no other supporting part group, so that only their own part should be used for moment compensation. It becomes the mass that can be. Further, since the 7 parts as the standing legs, that is, the right leg parts support all the part groups, the total mass M ₇ of all the parts of the aircraft can be used for moment compensation. The gravity center position of the mass M _{7 in} this case corresponds to the gravity center position of the airframe, not the foot (see FIG. 22).

  Then, based on the movement of the ground contact part such as the foot, the ZMP trajectory, and the desired trajectory group for each part group of the airframe, the movement pattern of each part group is stabilized according to the priority set in step S14. Input into processing.

  In this posture stabilization process, first, an initial value 1 is substituted for the process variable i (step S20). Then, the moment amount on the target ZMP, that is, the total moment compensation amount Ω when the target trajectory is set for all the part groups is calculated (step S21). To the total moment compensation amount Ω, the unknown external force moment and the unknown external force identified by the above equation are added as known terms to the sum of the moment amounts on the target ZMP of all the site groups.

  Further, the desired trajectory is used for a part for which the target trajectory has not been calculated.

Next, the absolute moment compensation amount coefficient α _i is set using the mass M _i that can be used for moment compensation of the part i calculated in step S15 (step S22), and the moment compensation amount Ω _i in the part group i is set. Is calculated (step S23).

Next, using the calculated moment compensation amount Ω _i of the i-th part, a ZMP equation (E1) relating to part i is derived (step S24).

Here, since the above ZMP equation has a large number of unknown variables, it is difficult to obtain a solution both analytically and numerically. Therefore, the desired center of gravity orbit r _Mi of the mass that can be used for moment compensation of the i-th part is a known variable, and the change amount Δr _Mi for the desired center of gravity orbit that can be used for moment compensation of the i-th part is an unknown variable. The approximate ZMP equation (E2) is derived. Here, r _Mi is a position vector of the center of gravity of the mass M _{i that} can be used for moment compensation in the i-th region group.

First, by solving this approximate ZMP equation, a change amount Δr _Mi for the desired center-of-gravity trajectory of the mass that can be used for moment compensation of the i-th part is calculated, and the target mass that can be used for moment compensation of the i-th part. Calculate the center of gravity trajectory using the following formula.

  In the case of a legged mobile robot in which each link is connected by a rotating joint, the above equation (E2) generally shares a motion in the Z direction, and thus becomes a nonlinear second-order differential equation with interference and is obtained analytically. It is difficult. Therefore, as shown below, it is assumed that the motion in the Z direction is not shared, and linearity / non-interference of the equation (E2) is performed.

Then, to calculate an approximate solution of the target barycentric trajectory of the mass available for the moment compensation of the i th site of the change amount [Delta] r _i of the mass points r _i of the i th site can be calculated from the approximate solution as strictly ZMP equation The operation of substituting into the equation (E1) to obtain the moment error, accumulating the inverted sign of this error on the right side of the linear / decoupled equation (E2), and obtaining the approximate solution again is the error The moment compensation motion of the part can be calculated by repeating until the value becomes equal to or less than a predetermined allowable value (step S25). In this way, it is possible to obtain the target trajectory for the part from the top to the i-th priority.

In order to calculate the trajectory of each mass point of the i-th part from the approximate solution of the target gravity center trajectory of the mass that can be used for moment compensation of the i-th part, an operation point is arranged at an arbitrary i-th part, Deriving a centroid vector C (X, Y, Z, θ _x , θ _y , θ _z ) with the translation position (X, Y, Z) or rotation angle (θ _x , θ _y , θ _z ) as an unknown variable, This centroid vector C (X, Y, Z, θ _x , θ _y , θ _z ) is set as an unknown variable on the left side, and the position vector r _Mi of the center of mass M _i is set as a known variable on the right side. Y, Z, θ _x , θ _y , θ _z ) = r _iMi, and the solution of this equation is calculated using a numerical search method or the like, or obtained analytically, so that The trajectory of each mass point can be determined.

  By performing such processing for all the site groups, a whole body motion pattern capable of stable motion (for example, walking) is generated.

  Since the acceleration sensors 96, 93, and 94 are disposed on the waist and the left and right feet, respectively, the above ZMP balance equation is derived directly and with high accuracy using the acceleration measurement results at these control target points. (As mentioned above). As a result, posture stability control based on the ZMP stability determination criterion can be executed more precisely at high speed in accordance with the processing procedure as shown in FIG.

E. As described in the preceding section D, the legged mobile robot 100 according to the present embodiment is basically based on the ZMP stability determination norm during walking or other stance work. Attitude control is performed to minimize the occurrence of the aircraft falling.

  However, in the unlikely event that a fall is unavoidable, a fall operation having an operation pattern that prevents damage to the aircraft as much as possible is performed. For example, in the ZMP balance equation described above, when an excessive external force F or external force moment M is applied to the aircraft, the moment error component T cannot be canceled only by the aircraft operation, and the posture stability cannot be maintained.

  FIG. 23 shows a schematic processing procedure in the form of a flowchart of the operation control of the airframe during the legged work in the legged mobile robot 100 according to the present embodiment.

  During the airframe operation, the ZMP balance equation (with ground contact (floor reaction force) sensors 91 and 92, acceleration sensors 93 and 94, acceleration sensors 96 arranged on the waist, and the sensor outputs of the acceleration sensors 96 arranged on the left and right feet is used. As described above, the foot contact position is always calculated (step S31).

For example, when an external force is applied to the aircraft, it is determined whether the next foot contact position can be planned, that is, whether the moment error due to the external force can be eliminated by the foot action plan. (Step S32). Whether or not the ground contact position of the foot can be planned is determined in consideration of the movable angle of each joint of the leg, the torque of each joint actuator, the joint force, the angular velocity, the angular acceleration, and the like. Of course, when an external force is applied, the moment error may be eliminated not only by the next step but also by a legged operation over several steps.

  At this time, if the foot can be planned, walking and other legged movements are continued (step S33).

  On the other hand, when an excessive external force or an external force moment is applied to the aircraft and the planning of the foot becomes impossible, the legged mobile robot 100 starts the overturning operation (step S34).

  In the case of an upright walking type legged robot as shown in FIGS. 1 and 2, since the center of gravity is high, if the robot falls inadvertently when it falls, it will be fatal to the robot itself or to the other party that collides due to the fall. There is a risk of damage. Therefore, in the present embodiment, a predetermined tipping operation is executed by rearranging the attitude of the airframe planned before the tipping down to a posture that minimizes the ZMP support polygon. Basically, the falling motion is searched based on the following two policies.

(1) The amount of change ΔS / Δt per time t of the area S of the support polygon of the airframe is minimized.
(2) The support polygon when the floor is dropped is maximized.

  By adopting such a fall method, it is possible to minimize damage by dispersing the impact received from the floor surface during the fall throughout the body.

  FIG. 24 shows, in the form of a flowchart, a processing procedure for the legged mobile robot 100 according to the present embodiment to perform a toppling operation when the foot cannot be planned. The overturning operation is realized by synchronously driving the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 connected in the height direction in accordance with the basic policy described above. The Such a processing procedure is actually realized by executing a predetermined machine operation control program in the main control unit 81 and controlling the driving of each unit.

  First, a link that minimizes the amount of change ΔS / Δt per time t of the area S of the support polygon formed by the landing site of the aircraft is searched (step S41).

  Next, the target landing point of the link that minimizes the change amount ΔS / Δt in the link selected in step S41 is searched (step S42).

  Next, landing of the link selected in the preceding step at the target landing point is due to restrictions of the hardware (movable angle of each joint, torque of each joint actuator, joint force, angular velocity, angular acceleration, etc.) Then, it is determined whether or not execution is possible (step S43).

  If it is determined that the link selected in the preceding step cannot be landed on the target landing point, the time change amount Δt is incremented by a predetermined position (step S44), and then the step Returning to S41, the link is reselected and the target landing point of the link is reset.

  On the other hand, when the link selected in the preceding step can be landed on the target landing point, the selected link is landed on the target landing point (step S45).

  Next, it is determined whether or not the potential energy of the aircraft is minimum, that is, whether or not the overturning operation has been completed (step S46).

  If the potential energy of the airframe is not yet minimum, the time change amount Δt is further incremented by a predetermined location (step S47), and the next target landing point is set so as to enlarge the support polygon (step S47). S48).

  Next, landing the selected link at the target landing point can be executed due to restrictions of the hardware (movable angle of each joint, torque of each joint actuator, joint force, angular velocity, angular acceleration, etc.) (Step S49).

  If it is determined that the link selected in the preceding step cannot be landed on the target landing point, the process returns to step S41 to re-select the link, as well as the target landing point of the link. Set again.

  On the other hand, when the link selected in the preceding step can be landed on the target landing point, the process proceeds to step S45, and the selected link is landed on the target landing point.

  Then, when the potential energy of the aircraft is minimized (step S46), since the landing of the aircraft on the floor surface is completed, the entire processing routine is terminated.

E-1. In FIG. 25, the legged mobile robot 100 is connected substantially parallel to the height direction of the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, the knee joint pitch axis 14, and the like. This model shows an operation of modeling as a link structure composed of a plurality of joint axes and falling down toward a supine posture by driving each joint pitch axis synchronously.

  It is assumed that the robot stands only at the sole that is the link end of the link structure (FIG. 25 (1)).

  At this time, by applying an external force or an external force moment, the moment error term T in the ZMP balance equation cannot be canceled, and the ZMP is supported in response to the ZMP deviating outside the ZMP stable region formed only by the sole. Start the overturning operation while maintaining the polygonal shape.

  In the overturning operation, first, a link that minimizes the change amount ΔS / Δt per time t of the area S of the support polygon formed by the landing site of the aircraft is searched, and the change amount ΔS / The target landing point of the hand that minimizes Δt is searched. Whether or not landing of the selected link at the target landing point is feasible due to restrictions of the aircraft hardware (movable angle of each joint, torque of each joint actuator, joint force, angular velocity, angular acceleration, etc.) Is determined.

  If it is feasible on the aircraft hardware, other links will land in addition to the already-planted foot link. Then, the ZMP is moved into the minimum support polygon formed by these landing links (FIG. 25 (2)).

  Next, as long as the aircraft hardware allows, the landing point is moved to expand the support polygon (FIG. 25 (3)).

  When the landing point can no longer be moved due to restrictions on the hardware such as the movable angle of each joint, torque of each joint actuator, joint force, angular velocity, and angular acceleration, this time, the link during landing It is determined whether or not the leaving link sandwiched between the two can be landed.

  When it is possible to land the floor link between the landing links on the machine hardware, these are landed to increase the number of landing links (FIG. 25 (4)).

  Furthermore, as long as the machine hardware allows, the landing point is moved to expand the support polygon (FIG. 25 (5)).

  Finally, one or more links from one end side of the link structure composed of a plurality of substantially parallel joint shafts connected in the height direction and two or more links from the other end are removed from the floor, and In a state where one or more links located in the middle are landed and the feet are landed, the posture in which the support polygon is maximized is formed while maintaining the ZMP in the support polygon. If the potential energy of the airframe is minimum in this posture, the overturning operation is complete.

  26 to 31 show how the actual machine falls from the standing posture to the supine posture. In the example shown in each figure, a state is shown in which an external force is applied from the front of the machine body to perform a backward-turning operation, but the operation state can be captured in six stages A to F.

  The body of the legged mobile robot is composed of a multi-link structure in which multiple joint axes with approximately parallel joint degrees of freedom are connected in the length direction. The link state between the landing site of the structure and the floor surface switches between the open link state and the closed link state. FIG. 32 shows a state in which a closed link system is constituted by both legs and the floor surface by supporting both legs in the standing posture. FIG. 33 shows a state in which an open link is constituted by both legs and the floor surface by supporting a single leg in a standing posture.

  In the present embodiment, the actuator for driving each joint is appropriately switched to a hard joint characteristic, a soft joint characteristic, or an intermediate joint characteristic in accordance with the switching of the link state at each fall stage. Realize a toppling action. Here, the hard joint characteristic is that the servo characteristic of the actuator / motor is high gain as shown in FIG. 12, and the phase advance amount in the high band is reduced, and the motor viscosity is shown in FIG. 17A. It is defined as setting to the maximum value of.

  Further, the intermediate joint characteristics include the servo characteristics of the actuator / motor as shown in FIG. 13, the gain is low and the gain is large, and the phase advance amount in the middle and high ranges is increased, and the motor viscosity is shown in FIG. 17A. It is defined as setting to the maximum value of. As shown in FIG. 13, the soft joint characteristics are such that the servo characteristics of the actuator and the motor are low gain, low gain, and the phase advance amount is high in the middle and high ranges, and the motor viscosity is the motor characteristics shown in FIG. 17B. It is defined as setting to 1/3 of the maximum value.

(A) State of supporting both legs before falling The state of supporting both legs is a state in which the posture is controlled, and a closed link system is configured by the lower limbs and the floor surface (see FIG. 26).

  At this time, the actuators of all the joint parts of the left and right legs are set to the intermediate joint characteristics, that is, the servo characteristics of the actuator / motor, as shown in FIG. While increasing, the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have high-speed response, and have a compliance that is higher than hard characteristics and lower than soft characteristics. Contributes to operation.

  Also, the neck roll, pitch, yaw and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. And the positioning accuracy of the joint which is a main component for controlling the amount of ΔS / Δt which is a standard for controlling the overturning operation is ensured, and the stability of the operation is increased.

(B) Start of overturning operation (closed link state)
Based on the output of the attitude sensor, it can be detected that the aircraft has started to fall. At the beginning of the fall, the lower limb and the floor surface still constitute a closed link system (see FIG. 27). In response to an external force or impact that would cause a fall, start a fall operation to minimize the impact.

  At this time, the actuators of the joint parts related to the stable region control such as the left and right thigh rolls and the pitch remain in the middle joint characteristics, that is, the servo characteristics of the actuator / motor are low and low gain as shown in FIG. In addition, the phase advance amount in the mid-high range is increased, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have high-speed response, and have a compliance that is higher than hard characteristics and lower than soft characteristics. Contributes to operation.

On the other hand, high-speed responsiveness and compliance are important in joint parts related to positional energy control such as left and right ankle roll axes, ankle pitch axes, and knee pitch axes. Therefore, the actuator of the joint part, a soft joint characteristics, i.e., the servo characteristics of the actuator motor with a larger amount of phase lead in the mid-high range and low-gain low-pass as shown in FIG. 13, a motor Is set to one third of the maximum value of the motor characteristics shown in FIG. 17B.

  Also, the neck roll, pitch, yaw and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. As a result, the positioning accuracy of the joint, which is the main component for controlling the amount of ΔS / Δt, which is a standard for controlling the overturning motion, is ensured, and the stability of the motion is increased.

(C) Progress of overturning operation (open link state)
When the overturning operation proceeds, the support leg leaves the floor, and the entire fuselage forms an open link (see FIG. 28). For example, it is possible to detect that the sole floats and becomes an open link based on the output of the sole force sensor (or contact sensor or the like).

  In this case, since all joint parts of the left and right legs are involved in the position energy control, high-speed response and compliance are important. Therefore, as shown in FIG. 13, the actuators of all joint parts of the legs are soft joint characteristics, that is, the servo characteristics of the actuator motor are increased in the low range with low gain and in the middle and high range, The viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG. 17B.

  Also, the neck roll, pitch, yaw and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. As a result, the positioning accuracy of the joint, which is the main component for controlling the amount of ΔS / Δt, which is a standard for controlling the overturning motion, is ensured, and the stability of the motion is increased.

(D) Immediate landing As a result of the fall, the aircraft lands, and the entire aircraft forms a closed link system (see FIG. 29). For example, the impact of landing can be detected using the output of a posture sensor or an acceleration sensor. At this time, the operation for minimizing the external force and impact received from the floor surface is started.

  In this case, since all joint parts of the left and right legs are involved in potential energy control, compliance is important. Therefore, as shown in FIG. 13, the actuators of all joint parts of the legs are soft joint characteristics, that is, the servo characteristics of the actuator motor are increased in the low range with low gain and in the middle and high range, The viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG. 17B. Thereby, since it becomes a soft system, the impact added to the whole body can be relieved.

  Further, each joint portion of the neck roll, the pitch, and the yaw has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, giving priority to positioning accuracy, it is also robust against disturbances such as vibration, and generates a motion that lifts the head from the floor at the moment of landing, and the head equipped with important parts such as the control unit is floored. You can protect against damage caused by collision with the surface.

Also, other joints sites, soft joint characteristics, i.e., the servo characteristics of the actuator motor with a larger amount of phase lead in the mid-high range and low-gain low-pass as shown in FIG. 13, the motor of the viscosity Is set to one third of the maximum value of the motor characteristics shown in FIG. 17B. Thereby, since it becomes a soft system, the impact added to the whole body can be relieved.

(E) Whole landing When the landing operation of the aircraft proceeds, the entire aircraft is landed, and the entire aircraft forms a closed link system (see FIG. 30). For example, it is possible to detect the end of vibration due to an impact using an attitude sensor.

  In this case, since all joint parts of the left and right legs are involved in potential energy control, compliance is important. Therefore, as shown in FIG. 13, the actuators of all joint parts of the legs are soft joint characteristics, that is, the servo characteristics of the actuator motor are increased in the low range with low gain and in the middle and high range, The viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG. 17B. Thereby, since it becomes a soft system, the impact added to the whole body can be relieved.

  Also, the neck roll, pitch, yaw and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(F) Steady posture after falling The entire airframe forms a closed link system (see FIG. 31). At this time, the vibration can be confirmed by using the posture sensor, and the state can be confirmed by the fact that a certain time (for example, 1 second) has passed and there is no new shock.

  At this time, the actuators of all the joint parts of the left and right leg parts are changed from soft joint characteristics to intermediate joint characteristics, that is, actuator / motor servo characteristics as shown in FIG. While increasing the phase advance amount, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have high-speed responsiveness, and obtain a compliance that is higher than the hard characteristic and lower than the soft characteristic, thereby increasing the positional accuracy and preparing for a return operation from a fall such as a rising operation.

  Also, the neck roll, pitch, yaw and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

E-2. In FIG. 34, the legged mobile robot 100 is connected substantially in parallel with the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, the knee joint pitch axis 14, and the like. This shows a motion modeled as a link structure composed of a plurality of joint axes, and the joint pitch axes are driven in a synchronously emphasized manner and fall down toward the prone posture.

  It is assumed that the robot stands only at the sole that is the link end of the link structure (FIG. 34 (1)).

  At this time, by applying an external force or an external force moment, the moment error term T in the ZMP balance equation cannot be canceled, and the ZMP is supported in response to the ZMP deviating outside the ZMP stable region formed only by the sole. Start the overturning operation while maintaining the polygonal shape.

  In the overturning operation, first, a link that minimizes the change amount ΔS / Δt per time t of the area S of the support polygon formed by the landing site of the aircraft is searched, and the change amount ΔS / The target landing point of the hand that minimizes Δt is searched. Whether or not landing of the selected link at the target landing point is feasible due to restrictions of the aircraft hardware (movable angle of each joint, torque of each joint actuator, joint force, angular velocity, angular acceleration, etc.) Is determined.

  If it is feasible on the aircraft hardware, other links will land in addition to the already-planted foot link. Then, the ZMP is moved into the minimum support polygon formed by these landing links (FIG. 34 (2)).

  Next, as long as the aircraft hardware allows, the landing point is moved to expand the support polygon (FIG. 34 (3)).

  When the landing point can no longer be moved due to restrictions on the hardware such as the movable angle of each joint, torque of each joint actuator, joint force, angular velocity, and angular acceleration, this time, the link during landing It is determined whether or not the leaving link sandwiched between the two can be landed.

  If it is possible on the hardware of the aircraft to land the landing links between the landing links, these are landed to increase the number of landing links (FIG. 34 (4)).

  Furthermore, as long as the machine hardware allows, the landing point is moved to expand the support polygon (FIG. 34 (5)).

  Finally, one or more links from one end side and two or more links from the other end side of the link structure composed of a plurality of substantially parallel joint shafts connected in the height direction are separated from the floor, and In a state where one or more links located in the middle are landed and the feet are landed, the posture in which the support polygon is maximized is formed while maintaining the ZMP in the support polygon. If the potential energy of the airframe is minimum in this posture, the overturning operation is complete.

  35 to 39 show how the actual machine falls from the standing posture to the prone posture. In the example shown in the figure, a state is shown in which an external force is received from the rear of the machine body and the vehicle is toppled backwards, but the operation status can be captured in five stages A to D.

  The body of the legged mobile robot is composed of a multi-link structure in which a plurality of joint axes having approximately parallel joint degrees of freedom are connected in the length direction. In the course of the overturning operation, the link state formed by the landing site of the multi-link structure and the floor surface is switched between the open link state and the closed link state (same as above). Then, at each stage of the fall, the actuator for driving each joint according to the switching of the link state is appropriately switched to a hard joint characteristic, a soft joint characteristic, or an intermediate joint characteristic, so that the adaptive fall operation can be performed. Is realized.

(A) State of supporting both legs before falling The state of supporting both legs is a state in which the posture is controlled, and a closed link system is configured by the lower limbs and the floor (see FIG. 35).

  At this time, the actuators of all the joint parts of the left and right legs are set to the intermediate joint characteristics, that is, the servo characteristics of the actuator / motor, as shown in FIG. While increasing, the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have high-speed response, and have a compliance that is higher than hard characteristics and lower than soft characteristics. Contributes to operation.

  The neck roll, pitch, yaw, left and right elbow pitches, and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. In addition, the phase advance amount at is reduced, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. As a result, the positioning accuracy of the joint, which is the main component for controlling the amount of ΔS / Δt, which is a standard for controlling the overturning motion, is ensured, and the stability of the motion is increased.

(B) Start of overturning operation (closed link state)
Based on the output of the attitude sensor, it can be detected that the aircraft has started to fall. At the beginning of the fall, the closed link system is still composed of the lower limbs and the floor (see FIG. 36). In response to an external force or impact that would cause a fall, start a fall operation to minimize the impact.

  At this time, the actuators of the joint parts related to the stable region control such as the left and right thigh rolls and the pitch remain in the middle joint characteristics, that is, the servo characteristics of the actuator / motor are low and low gain as shown in FIG. In addition, the phase advance amount in the mid-high range is increased, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have high-speed response, and have a compliance that is higher than hard characteristics and lower than soft characteristics. Contributes to operation.

  On the other hand, high-speed responsiveness and compliance are important in joint parts related to positional energy control such as left and right ankle roll axes, ankle pitch axes, and knee pitch axes. Therefore, the actuators of these joint parts are made to have soft joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. The viscosity is set to one third of the maximum value of the motor characteristic shown in FIG. 17B.

Also, in order to interfere with the impact applied to the torso by wearing the left and right arms when landing, the left and right elbow pitch joint part actuators have soft joint characteristics to prepare for shock absorption during landing.

  In addition, the actuator of the joint part of the neck roll, pitch, and yaw has a hard joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. As a result, the positioning accuracy of the joint, which is the main component for controlling the amount of ΔS / Δt, which is a standard for controlling the overturning motion, is ensured, and the stability of the motion is increased.

  Further, the other joint parts have intermediate joint characteristics, that is, servo characteristics of the actuator and motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have a lower positional accuracy than in the case of the hard joint characteristics, but high-speed response and compliance are obtained to prepare for a fall.

(C) Progress of overturning operation (open link state)
When the overturning operation proceeds, the support leg leaves the floor, and the entire fuselage forms an open link (see FIG. 37). For example, it is possible to detect that the sole floats and becomes an open link based on the output of the sole force sensor (or contact sensor or the like).

  In this case, since all joint parts of the left and right legs are involved in the position energy control, high-speed response and compliance are important. Therefore, as shown in FIG. 13, the actuators of all joint parts of the legs are soft joint characteristics, that is, the servo characteristics of the actuator motor are increased in the low range with low gain and in the middle and high range, The viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG. 17B.

Also, in order to interfere with the impact applied to the torso by wearing the left and right arms when landing, the left and right elbow pitch joint part actuators have soft joint characteristics to prepare for shock absorption during landing.

  In addition, the actuator of the joint part of the neck roll, pitch, and yaw has a hard joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration. And the positioning accuracy of the joint which is a main component for controlling the amount of ΔS / Δt which is a standard for controlling the overturning operation is ensured, and the stability of the operation is increased.

  Further, the other joint parts have intermediate joint characteristics, that is, servo characteristics of the actuator and motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support legs have a lower positional accuracy than in the case of stiff joint characteristics, but get high-speed response and compliance to prepare for a fall.

(D) Immediate landing As a result of the fall, the aircraft lands, and the entire aircraft forms a closed link system (see FIG. 38). For example, the impact of landing can be detected using the output of a posture sensor or an acceleration sensor. At this time, the operation for minimizing the external force and impact received from the floor surface is started.

  In this case, since all joint parts of the left and right legs are involved in potential energy control, compliance is important. Therefore, as shown in FIG. 13, the actuators of all joint parts of the legs are soft joint characteristics, that is, the servo characteristics of the actuator motor are increased in the low range with low gain and in the middle and high range, The viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG. 17B. Thereby, since it becomes a soft system, the impact added to the whole body can be relieved.

Also, in order to interfere with the impact applied to the torso by wearing the left and right arms when landing, the left and right elbow pitch joint part actuators have soft joint characteristics to absorb the impact during landing.

  Further, each joint portion of the neck roll, the pitch, and the yaw has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, giving priority to positioning accuracy, it is also robust against disturbances such as vibration, and generates a motion that lifts the head from the floor at the moment of landing, and the head equipped with important parts such as the control unit is floored. You can protect against damage caused by collision with the surface.

Also, other joints sites, soft joint characteristics, i.e., the servo characteristics of the actuator motor with a larger amount of phase lead in the mid-high range and low-gain low-pass as shown in FIG. 13, the motor of the viscosity Is set to one third of the maximum value of the motor characteristics shown in FIG. 17B. Thereby, since it becomes a soft system, the impact added to the whole body can be relieved.

(E) Steady posture after falling The entire body forms a closed link system (see FIG. 39). At this time, the vibration can be confirmed by using the attitude sensor, and the state can be confirmed by the fact that a certain time (for example, 1 second) has passed and there is no new impact.

  At this time, the actuators of all the joint parts of the left and right leg parts are changed from soft joint characteristics to intermediate joint characteristics, that is, actuator / motor servo characteristics as shown in FIG. While increasing the phase advance amount, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the support leg has a quick response, and has a compliance that is higher than the hard characteristic and lower than the soft characteristic, and has a positional accuracy that is higher than the soft characteristic and lower than the hard characteristic. Contribute.

  The left and right elbow pitches, neck rolls, pitches, yaw, and other joint parts have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. In addition, the phase advance amount at is reduced and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

F. Stand-up operation from the floor position Legged movement to start from the floor position such as the supine position or the prone position, or to get the work self-contained to get up autonomously and restart the work when falling The robot 100 needs to get up and realize the operation.

  At this time, if an attempt is made to get up by an unplanned trajectory, an excessive external force moment is applied, and the joint actuator requires a high output torque. As a result, it is necessary to increase the size of the motor, and the power consumption increases accordingly. In addition, the manufacturing cost increases as the weight of the aircraft increases. The increase in weight further makes it difficult to get up. Alternatively, there may be a situation in which posture stability cannot be maintained due to an external force moment generated during the process of getting up, and the person cannot get up in the first place.

  Therefore, in the present embodiment, the legged mobile robot 100 performs the rising motion having the motion pattern that minimizes the external force moment. This can be realized by combining postures that minimize the ZMP support polygon in time series.

  Further, the legged mobile robot 100 according to the present embodiment has a height such as the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 (see FIG. 3). A link structure in which a plurality of pitch axes are connected in series in a direction (when viewed from the lateral direction). Accordingly, the plurality of joint pitch axes 4 to 14 are driven synchronously and in a predetermined sequence to realize a rising motion based on a motion pattern that minimizes the ZMP support polygon.

F-1. In FIG. 40, the legged mobile robot 100 according to the present embodiment synchronously emphasizes the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14. A processing procedure for driving and performing a rising operation is shown in the form of a flowchart. Such a processing procedure is actually realized by executing a predetermined machine operation control program in the main control unit 81 and controlling the driving of each unit.

  In FIG. 41, the legged mobile robot 100 according to the present embodiment drives the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 in a synchronously emphasized manner, and is in a supine posture. The joint link model shows how to get up from the beginning. However, in the illustrated link structure, the center-of-gravity position of the entire body is set to the link connecting the trunk joint and the hip joint, and this link will be referred to as a “center-of-gravity link” below. The “center of gravity link” is defined as described above in a narrow sense, but may be a link in which the center of gravity of the entire aircraft exists in a broad sense. For example, in an aircraft that does not have a trunk axis, a link including a trunk tip where the center of gravity of the entire aircraft is located corresponds to this. FIG. 42 shows a state where the actual machine gets up from the supine posture.

  Hereinafter, with reference to the flowchart shown in FIG. 40, the operation for raising the aircraft from the basic posture will be described.

  First, an attitude with the lowest potential energy is searched for on the floor (step S51). This corresponds to the basic supine posture, and as shown in FIGS. 41 (1) and 42 (A), the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, the knee joint used for the rising motion. All the links connecting the pitch shafts 14 are in contact with each other. At this time, by taking the posture with the lowest potential energy, it is possible to measure the inclination and shape of the road surface and confirm whether or not the rising operation is possible.

  In this basic posture, the narrowest support polygon is searched for within the ground contact polygon formed by the floor contact link (step S52). At this time, it is determined whether or not a ZMP trajectory can be planned when at least two or more links are removed from one end of the aircraft. The planability of ZMP can be determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like.

  Next, two or more links that are not involved in the narrowest support polygon among the grounded polygons are removed from the floor (step S53).

Step S53 corresponds to FIG. On the actual machine, the lower body side including the center-of-gravity link connecting the trunk joint and the hip joint is extracted as a support polygon, and two or more links from the other shoulder joints to the trunk joint are left as links that do not participate in the support polygon. To do. First, the lift arms of the left and right as shown in FIG. 42 (B), by driving the trunk joint pitch axis actuator A _9, are subjected to raised upper body as shown in FIG. 42 (C). By lifting the arm first, the moment can be reduced and the required maximum torque can be reduced.

  Next, one or more floor links are bent from one end side to land the end of the link end to form a narrower grounding polygon (step S54).

Step S54 corresponds to FIG. 1 (3) and FIG. 42 (D). On the actual machine, in a state where two or more links including the shoulder joint are leaving the floor, the arm is bent at the shoulder joint pitch axis and the hand which is the end of the link end is brought into contact with the floor. Then, by gradually approaching the hand to the trunk pitch axis side, which is the position of the center of gravity of the aircraft, a grounding polygon narrower than the original on-floor posture is formed.

In the actual machine at this time, the left and right arm portions are spread to the side by driving the left and right shoulder joint roll axis A ₅ , and then the arm portion is once rotated 180 degrees by driving the upper arm yaw axis A ₆ . The arm is gradually lowered by driving the shoulder joint pitch axis A ₄ . Then, a narrower grounding polygon is formed by landing the hand.

  When a new ground polygon is formed in this way, it is checked whether ZMP can be set for the ground polygon (step S55). This is determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like. Then, the ZMP is moved to the ground polygon and a new support polygon is formed (step S56).

  Here, it is determined whether or not the support polygon is sufficiently narrow (step S57). This determination is based on whether the center-of-gravity link connecting the trunk pitch axis and the hip joint pitch axis can be removed, or, as shown in FIG. 42 (E), the ZMP is moved into a ZMP stable region that can be formed only by the foot. It is determined whether or not it is possible to take into account the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like.

  If the support polygon is not sufficiently narrow yet, after moving the landing point to make the support polygon smaller (step S60), the process returns to step S52 to retry the formation of a narrower support polygon. To do. Then, the narrowest support polygon is searched for within the ground contact polygon formed by the floor contact link (step S52). Next, it is determined whether or not ZMP can be planned when at least two or more links are left from the other end of the aircraft. The planability of ZMP can be determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like.

Next, two or more links that do not participate in the narrowest support polygon among the floor-contacting polygons are left (step S53). This corresponds to FIGS. 41 (4) to (5). On an actual machine, two or more links continuous from the other end side including the knee joint pitch axis are left as links that do not participate in the support polygon. Then, one or more leaving links are bent from one end side to land the end of the link end to form a narrower ground contact polygon (step S54). At this time, the actual machine first lifts the right leg by driving the hip joint pitch axis A ₁₂ of the right leg, and then flexes the right leg by driving the knee joint actuator A ₁₄ to land the sole of the foot. Next, the right leg is lifted by driving the leg hip joint pitch axis A ₁₂ , the left leg is bent by driving the knee joint actuator A ₁₄ , and the sole of the foot is landed. In this manner, by gradually approaching the sole to the hip joint pitch axis 12 side, which is the position of the center of gravity of the body, a grounding polygon narrower than the original on-floor posture can be formed.

  When a new ground polygon is formed in this way, it is checked whether ZMP can be set for the ground polygon (step S55). This is determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like. Then, the ZMP is moved to the ground polygon and a new support polygon is formed (step S56).

  Here, it is determined again whether or not the support polygon is sufficiently narrow (step S57). This determination is based on whether the center of gravity link connecting the trunk pitch axis and the hip joint pitch axis can be removed from the floor, or whether the ZMP can be moved within the ZMP stable region that can be formed only by the foot. Judgment is made in consideration of the movable angle, the torque, joint force, angular velocity, angular acceleration, etc. of each joint actuator connecting the links. In the attitude of the actual machine shown in FIG. 42 (F), it is determined that a sufficiently narrow support polygon is formed. Regarding the angle of the arm when reducing the support polygon, it is desirable that the angle formed by the perpendicular line drawn from the shoulder axis in the floor direction and the central axis of the arm is within a predetermined angle based on the torque amount.

  And in response to the support polygon of the fuselage becoming sufficiently narrow, the center of gravity link is left with the ends of both link ends of the support polygon in contact with the floor, and the landing links at both link ends are used. While maintaining the ZMP in the formed support polygon, the distance between the ends of both link ends forming the support polygon is reduced, and the ZMP is moved to the other end of the link structure (step S58). ). This corresponds to FIGS. 41 (6) to (7). On the actual machine, as shown in FIGS. 42 (G) to (H), the trunk pitch axis and the hip joint pitch axis are connected with the hand and the sole as the ends of both link ends of the contact polygon in contact with the floor. The center-of-gravity link is removed from the floor, and the distance between the hand and the sole is gradually reduced, and the ZMP is moved toward the sole.

  Then, in response to the ZMP having entered the ground polygon formed by only the second predetermined number of floor-contact links or less from the other end of the link structure, the ZMP is accommodated in the ground polygon. The rising operation is completed by leaving the first predetermined number of links or more from the one end side of the link structure and extending the leaving link in the length direction (step S59). This corresponds to FIG. 41 (8).

  On the actual machine, as shown in FIGS. 42 (H) to (I), in response to the ZMP having entered the grounding polygon formed by the sole, the ZMP remains accommodated in the grounding polygon. By lifting the link from the shoulder pitch axis 4 to the knee pitch axis 14 and extending the floor link in the length direction, the rising motion is completed.

  When extending the bed leaving link in the length direction, which is the final stage of getting up, it is efficient in operating the aircraft to operate using the knee joint pitch axis having a larger mass operation amount.

  In step S53, if two or more links that do not participate in the smallest support polygon cannot be removed, an attempt is made to leave two or more landing links inside the largest support polygon (step S53). S61).

  If step S61 cannot be executed, the rising operation is stopped. If step S61 can be executed successfully, the landing point is further moved to further reduce the support polygon (step S62).

  If step S62 cannot be executed, the rising operation is stopped. If step S62 can be executed successfully, it is checked whether the ZMP can be moved to a stable region that can be formed by the foot (step S63). If the ZMP cannot be moved within the stable region, the process returns to step S61, and the same process for reducing the support polygon is repeated. If the ZMP can be moved within this stable region, the process proceeds to step S58 to perform a return operation to the basic posture.

  Hereinafter, the rising operation from the posture on the floor on the back will be described in 10 stages A to J with reference to FIGS. 43 to 52.

  The body of a legged mobile robot is composed of a multi-link structure in which multiple joint axes with approximately parallel joint degrees of freedom are connected in the length direction. The link state between the landing site of the structure and the floor surface switches between the open link state and the closed link state. Then, at each stage of rising, the actuator for driving each joint according to the switching of the link state is appropriately switched to a hard joint characteristic, a soft joint characteristic, or an intermediate joint characteristic, thereby adaptively rising up. Is realized.

(A) Basic posture on the back This is a state in which the posture is controlled, and the lower limbs, the waist, and the trunk constitute a closed link system with respect to the floor (see FIG. 43).

  The legged mobile robot performs a rising motion from a supine posture with an operation pattern that minimizes the ZMP support polygon. However, as described with reference to FIG. Search for a ZMP support polygon. Therefore, FIG. 12 shows hard joint characteristics, that is, servo characteristics of the actuator and motor, for the actuator of the joint portion related to driving of the arm portion such as the left and right shoulder pitches, shoulder rolls, and elbow pitches in preparation for the rising motion As described above, the gain is high in the entire band and the phase advance amount in the high band is reduced, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The viscosity of the motor is set to the maximum value of the motor characteristic shown in FIG. 17A. As a result, the support legs have high-speed response, and have a compliance that is higher than hard characteristics and lower than soft characteristics. Contributes to operation.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(B) Raise both arms upward The lower body side including the center of gravity link connecting the trunk joint and hip joint is extracted as a support polygon, and two or more links from the other shoulder joints to the trunk joint are supported. Leave as a link that does not involve. In this case, the lower limbs, waist, and trunk constitute a closed link system with respect to the floor (see FIG. 44).

  At this time, in the joint parts related to the bed leaving movement such as the shoulder yaw axis and the elbow pitch axis, positioning accuracy becomes important during the period until the floor is touched in order to form a narrower ground contact polygon. As shown in FIG. 12, the actuator has a hard joint characteristic, that is, the servo characteristic of the actuator / motor, has a high gain in all bands and a small phase advance amount in the high band, and the motor viscosity is shown in FIG. 17A. Set to the maximum value of the characteristic.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity shown in FIG. 17A is maintained.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. The motor characteristics shown in FIG. 17A are maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(C) Raise the trunk while maintaining the relative angle between both arms and the trunk. Raise both the left and right arms, and then raise the body. In this case, the lower limbs constitute a closed link system with respect to the floor surface (see FIG. 45). It detects its posture using the posture sensor and its own joint angle information. By lifting the arm first, the moment can be reduced and the required maximum torque can be reduced.

  After this, both the left and right arms go to the floor, so that the actuators of these joints have soft joint characteristics, that is, the servo characteristics of the actuator / motor, as shown in FIG. The phase advance amount in the region is increased, and the viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity shown in FIG. 17A is maintained.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(D) Move both arms rearward In a state where two or more links including the shoulder joint are leaving the floor, the arm is bent along the shoulder joint pitch axis, and the hand which is the end of the link end is brought into contact with the floor. Then, by gradually approaching the hand to the trunk pitch axis side, which is the position of the center of gravity of the aircraft, a grounding polygon narrower than the original on-floor posture is formed. As a result, the arms, trunk, waist, and lower limbs form a closed link system with respect to the floor (see FIG. 46). Arm tip grounding can be confirmed using the posture sensor and its own joint angle information.

  At this time, in joints related to rising motion such as left and right shoulder pitch, shoulder yaw, elbow pitch, etc., speed response and compliance are important during the period until contact with the floor to form a narrower ground contact polygon. As shown in FIG. 13, the actuators of these joint parts have intermediate joint characteristics, that is, the servo characteristics of the actuator and motor. As shown in FIG. The viscosity is set to the maximum value of the motor characteristic shown in FIG. 17A. As a result, the support legs have high-speed responsiveness, and obtain a compliance that is higher than the hard characteristic and lower than the soft characteristic, thereby increasing the positional accuracy and preparing for the next operation.

  Further, the actuators in the joint parts of the left and right lower limbs increase the phase advance amount in the middle and high ranges with intermediate joint characteristics, that is, the servo characteristics of the actuator / motor, as shown in FIG. At the same time, the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, it has high-speed response, and has compliance that is higher than hard characteristics and lower than soft characteristics, so it has position accuracy that is higher than soft characteristics and lower than hard characteristics, contributing to stable operation in a closed link state. To do.

  Further, the actuator of the joint portion other than the above has an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The viscosity of the motor is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

(E) Bend the knee of the right leg to bring the sole close to the trunk. In order to make the support polygon sufficiently narrow, the ZMP is moved into a ZMP stable region that can be formed only by the leg. The arm, trunk, waist, and left lower limb constitute a closed link system with respect to the floor (see FIG. 47). It can be confirmed that it becomes a swing leg using the posture sensor and its own joint angle information.

  At this time, the right leg turns into a free leg. And, at each joint part related to bed leaving movement such as right thigh roll and right thigh pitch, high speed response and compliance are important during the period until contacting the floor to form a narrower ground contact polygon. As shown in FIG. 12, the actuator of the joint portion of the joint part has a hard joint characteristic, that is, the servo characteristic of the actuator and motor. Set to the maximum value of the motor characteristics shown in 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  Also, since the right ankle roll, right ankle pitch, etc. head to the floor, the actuators of these joint parts are soft joint characteristics, that is, the servo characteristics of the actuator / motor are low and low gain as shown in FIG. In addition, the phase advance amount in the mid-high range is increased, and the viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG.

  In addition, the left leg that does not operate at this stage and the actuators of joints other than those described above have intermediate joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. And the viscosity of the motor is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

(F) Bend the knee of the right leg to bring the sole close to the trunk In order to make the support polygon sufficiently narrow, the ZMP is moved into a ZMP stable region that can be formed only by the leg. The arm, trunk, waist, and right lower limb constitute a closed link system with respect to the floor (see FIG. 48). It can be confirmed that it becomes a swing leg using the posture sensor and its own joint angle information.

  At this time, the right leg turns into a supporting leg and the left leg turns into a free leg. And in each joint part related to the floor leaving movement such as left thigh roll and left thigh pitch, high speed responsiveness and compliance are important during the period until contacting the floor to form a narrower ground contact polygon. As shown in FIG. 12, the actuator of the joint part has a high joint characteristic, that is, the servo characteristic of the actuator / motor. Set to the maximum value of the motor characteristics shown in 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  Further, since the left ankle roll, the left ankle pitch, and the like are directed to the floor, the actuators of these joint parts have soft joint characteristics, that is, the servo characteristics of the actuator motor are low in the low range and low gain as shown in FIG. In addition, the phase advance amount in the mid-high range is increased, and the viscosity of the motor is set to one third of the maximum value of the motor characteristics shown in FIG.

The actuator of a joint part of the right leg that does not work at this stage, the joint characteristics of the intermediate, i.e., the amount of phase lead in and mid-high range at low gain servo characteristics of the actuator motor in the low range, as shown in FIG. 13 And the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the left leg can respond quickly and gain compliance. In addition, the viscosity of the motor increases.

  Further, the actuator of the joint portion other than the above has an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The viscosity of the motor is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

(G) A five-point support with the bottom of both feet approaching the trunk is a posture in which a sufficiently narrow support polygon is formed, and the arms, trunk, waist and lower limbs are closed links to the floor Configure the system (see FIG. 49). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

  At this time, the actuator of the joint part that performs an operation of searching for the narrowest support polygon such as the ankle roll axis and the ankle pitch axis is returned from the soft joint characteristic to the intermediate joint characteristic. As a result, compliance is obtained while maintaining high-speed response. In addition, the viscosity of the motor increases.

  Further, the actuator of the joint portion other than the above has an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The viscosity of the motor is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

(H) Use the legs, trunk, and shoulders to get up with the arms and legs supported at 4 points. Trunk pitch with the hands and soles as the ends of both link ends of the contact polygon in contact with the floor The center-of-gravity link connecting the shaft and the hip joint pitch shaft is removed from the floor, and the distance between the hand tip and the sole is gradually shortened to move the ZMP toward the sole. The arms, trunk, waist, and lower limbs constitute a closed link system with respect to the floor (see FIG. 50). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

At this time, in order to form narrower ground contact polygons in the jointed parts such as ankle roll and ankle pitch, high-speed response and compliance are important. , i.e., the servo characteristics of the actuator motor with a larger amount of phase lead in the mid-high range and low-gain low-pass as shown in FIG. 13, the maximum value of the motor characteristic indicating the viscosity of the motor in FIG. 17B Set to one third.

  Further, as shown in FIG. 13, the actuator of the joint portion related to the operation of narrowing the support polygon such as the shoulder pitch, the shoulder roll, and the knee pitch has a low intermediate joint characteristic, that is, the servo characteristic of the actuator / motor as shown in FIG. A low gain in the frequency range and a large phase advance amount in the middle and high frequency range, while maintaining the motor viscosity at the maximum value of the motor characteristics shown in FIG. By obtaining compliance below the hour, it has a positional accuracy that is above the soft characteristic and below the hard characteristic, and contributes to stable operation in the closed link state.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(I) The arm is removed from the floor, and the leg is supported at two points. In response to the ZMP entering the grounding polygon formed by the sole, the ZMP is accommodated in the grounding polygon. The link from the shoulder pitch axis 4 to the knee pitch axis 14 is removed from the floor, and the release link is extended in the length direction. In this case, the waist and lower limbs constitute a closed link system with respect to the floor (see FIG. 51). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

  At this time, in order to reinforce the posture stability control in the extension operation and the two-point support state, the actuators of the joint parts of the ankle roll and the ankle pitch are shown as intermediate joint characteristics, that is, the servo characteristics of the actuator / motor. As shown in Fig. 17A, the gain is low, the gain is high, and the phase advance amount in the middle and high ranges is increased, and the motor viscosity is set to the maximum value of the motor characteristics shown in Fig. 17A. By obtaining compliance above the time and below the soft characteristics, the positional accuracy is increased and prepared for the next operation.

  Further, the actuators of the left and right arm parts such as shoulder pitch, shoulder roll, and elbow pitch have hard joint characteristics, that is, the servo characteristics of the actuator / motor with high gain in the entire band as shown in FIG. The phase advance amount in the high range is reduced, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. Is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

(J) Transition to the basic posture The posture is controlled in a basic standing posture, and the waist and lower limbs constitute a closed link system with respect to the floor (see FIG. 52).

  At this time, the actuator of each joint part of the ankle roll and the ankle pitch is set to the intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity is maintained at the maximum value of the motor characteristics shown in FIG. 17A, and the compliance is higher than when hard characteristics and less than soft characteristics while having high-speed response. In addition, it has position accuracy below that of hard characteristics, and contributes to stable operation in a closed link state.

  Further, the actuators of the left and right arm parts such as shoulder pitch, shoulder roll, and elbow pitch have hard joint characteristics, that is, the servo characteristics of the actuator / motor with high gain in the entire band as shown in FIG. The phase advance amount in the high region is reduced, the motor viscosity is maintained at the maximum value of the motor characteristics shown in FIG. 17A, and positioning accuracy is prioritized to make it robust against disturbances such as vibration.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. Is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

  As described above, when the aircraft rises from the supine posture, the actuator characteristics are set to increase the low-frequency gain, decrease the phase advance amount, and increase the joint viscous resistance as shown in FIG. By doing so, highly accurate positioning becomes possible. Therefore, since the accuracy of operation control is improved in all of (A) to (J), the accuracy of the size of the support polygon can be ensured.

  Further, the actuator characteristics are set so that the low-frequency gain is small, the phase advance amount is large, and the viscous resistance of the joint is small as shown in FIG. And can give high speed responsiveness. Therefore, during the state transition of (B) to (D), (E) to (G), and (H) to (I), the movement of the arms and legs and the landing operation are smoothed and the energy consumption is reduced. can do.

F-2. 53. Operation to get up from the basic prone posture In FIG. 53, the legged mobile robot 100 according to the present embodiment synchronously emphasizes the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14. The joint link model shows how to drive and get up.

  The legged mobile robot 100 according to the present embodiment can basically get up from the prone posture according to the processing procedure shown in the form of a flowchart in FIG. Hereinafter, with reference to the flowchart shown in FIG. 40, the operation for raising the aircraft from the basic prone posture will be described.

  First, a posture with the lowest potential energy is taken in the posture on the floor (step S51). This corresponds to the basic prone posture, and as shown in FIGS. 53 (1) and 54 (A), the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint used for the rising motion. All the links connecting the pitch shafts 14 are in contact with each other.

  In this basic prone posture, the narrowest support polygon is searched for within the ground contact polygon formed by the floor contact link (step S52). At this time, it is determined whether or not ZMP can be planned when at least two or more links are removed from one end of the aircraft. The planability of ZMP can be determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like.

Next, two or more links that are not involved in the narrowest support polygon among the grounded polygons are removed from the floor (step S53). Step S53 corresponds to FIG. 53 (2). On the actual machine, the lower body side including the center-of-gravity link connecting the trunk joint and the hip joint is extracted as a support polygon, and two or more links from the other shoulder joints to the trunk joint are left as links that do not participate in the support polygon. To do. First, the shoulder roll axis actuator A ₅ of both the left and right arms is operated, slid on the floor surface and rotated about 90 degrees around the shoulder roll axis, and then the upper arm yaw axis actuator A ₆ is operated, Each arm is rotated about 180 degrees around the upper arm yaw axis. Then, as shown in FIG. 54 (B), the shoulder roll shaft actuator A ₅ is further operated and slid and rotated about 90 degrees around the shoulder roll shaft, and as shown in FIG. Move the arm to the side of the head.

  Next, one or more floor links are bent from one end side to land the end of the link end to form a narrower grounding polygon (step S54). Step S54 corresponds to FIG. 53 (3) and FIG. 54 (D).

When a new ground polygon is formed, it is checked whether ZMP can be set for the ground polygon (step S55). This is determined in consideration of the movable angle of the link structure, the torque of each joint actuator connecting the links, the joint force, the angular velocity, the angular acceleration, and the like. Then, the ZMP is moved to the ground polygon and a new support polygon is formed (step S56). On the actual machine, as shown in FIG. 54 (D), the elbow pitch shaft 7 is fixed and the left and right arms are stretched straight, and now the shoulder pitch axis actuator A ₄ , the trunk pitch axis actuator A ₉ , hip joint pitch axis A ₁₂ , and knee joint pitch axis actuator A ₁₄ are actuated to form a support polygon having a closed link posture in which the hand and the left and right knees are grounded.

  If it cannot be said that the supporting polygon is sufficiently narrow, the landing point is moved to reduce the supporting polygon (step S60). On the actual machine, as shown in FIG. 54 (E), the left and right arms are kept straight and the hand is gradually brought closer to the sole side, which is the other landing point, so that a narrower support is provided. Form a square.

  Here, it is determined whether or not the support polygon is sufficiently narrow (step S57). This determination is based on whether the center of gravity link that connects the trunk pitch axis and the hip joint pitch axis can be removed from the floor, or whether the ZMP can be moved within the ZMP stable region that can be formed only by the foot. Judgment is made in consideration of the movable angle of the body, the torque, joint force, angular velocity, angular acceleration, etc. of each joint actuator connecting the links.

  Then, in response to the support polygon of the fuselage becoming sufficiently narrow, while maintaining the ZMP in the support polygon formed by the landing links at both link ends, The interval between the end portions is reduced, and the ZMP is moved to the other end side of the link structure (step S58). This corresponds to FIGS. 53 (6) to (7). On the actual machine, as shown in FIGS. 54 (D) to (E), the distance between the hand and the foot is gradually increased with the hand and the foot as the ends of the link ends of the ground contact polygon in contact with the floor. The ZMP is moved toward the sole.

  Then, in response to the ZMP having entered the ground polygon formed by only the second predetermined number of floor-contact links or less from the other end of the link structure, the ZMP is accommodated in the ground polygon. The rising operation is completed by leaving the first predetermined number of links or more from the one end side of the link structure and extending the leaving link in the length direction (step S59). This corresponds to FIG. 53 (8).

  On the actual machine, as shown in FIGS. 54 (E) to (F), in response to the ZMP having entered the grounding polygon formed by the sole, the ZMP remains accommodated in the grounding polygon. By lifting the link from the shoulder pitch axis 4 to the knee pitch axis 14 and extending the floor link in the length direction, the rising motion is completed.

  When extending the bed leaving link in the length direction, which is the final stage of getting up, it is efficient in operating the aircraft to operate using the knee joint pitch axis having a larger mass operation amount.

  Hereinafter, the rising operation from the supine floor posture will be described in seven stages A to G with reference to FIGS. 55 to 61.

  The body of a legged mobile robot is composed of a multi-link structure in which multiple joint axes with approximately parallel joint degrees of freedom are connected in the length direction, but this multi-link is in the process of getting up from a prone posture. The link state between the landing site of the structure and the floor surface switches between the open link state and the closed link state. And at every stage of rising, the actuator for driving each joint according to the switching of the link state is switched appropriately to hard joint characteristics, soft joint characteristics, and intermediate joint characteristics, so that adaptive rising operation Is realized.

(A) Basic posture of prone position This is a state in which the posture is controlled, and the lower limbs, the waist, and the trunk constitute a closed link system with respect to the floor (see FIG. 55).

  The legged mobile robot performs a rising motion from a supine posture with an operation pattern that minimizes the ZMP support polygon. However, as described with reference to FIG. Search for a ZMP support polygon. Therefore, FIG. 12 shows hard joint characteristics, that is, servo characteristics of the actuator and motor, for the actuator of the joint portion related to driving of the arm portion such as the left and right shoulder pitches, shoulder rolls, and elbow pitches in preparation for the rising motion. As described above, the gain is high in the entire band and the phase advance amount in the high band is reduced, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The viscosity of the motor is set to the maximum value of the motor characteristic shown in FIG. 17A. As a result, it has high-speed response, and has compliance that is higher than hard characteristics and lower than soft characteristics, so it has position accuracy that is higher than soft characteristics and lower than hard characteristics, contributing to stable operation in a closed link state. To do.

  In addition, trunk rolls, trunk pitches, and actuators of joint parts other than those described above have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. While the advance amount is reduced, the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(B) Move both arms from the side facing the overhead direction The lower body side including the center-of-gravity link connecting the trunk joint and the hip joint is extracted as a support polygon, and two or more from the other shoulder joints to the trunk joint Leave the link as a link that does not participate in the support polygon. Then, by operating the shoulder roll axis actuator A _5, swirled by approximately 90 degrees to the shoulder roll axis and grinded, to move the arms to the side of the head. In this case, the lower limbs, waist, and trunk constitute a closed link system with respect to the floor surface (see FIG. 56). However, both arms are not grounded.

  At this time, positioning accuracy becomes important during the period until contact with the floor in order to form a narrower grounding polygon at joints related to getting off and turning, such as the shoulder yaw axis, shoulder roll axis, and shoulder pitch axis. As shown in FIG. 12, the actuators of these joint parts have a hard joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. Is set to the maximum value of the motor characteristics shown in FIG. 17A.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity shown in FIG. 17A is maintained.

  In addition, trunk rolls, trunk pitches, and actuators of joint parts other than those described above have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. While the advance amount is reduced, the motor viscosity shown in FIG. 17A is maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(C) Raise both arms upwards Move both left and right arms to the side of the head. The thigh, waist, trunk, and upper limb constitute a closed link system with respect to the floor (see FIG. 57). This state can be confirmed from the posture (grounding state) using the posture sensor and own joint angle information.

  At this time, both the left and right legs turn into swing legs. And in joint parts such as ankle roll and ankle pitch, high-speed response and compliance are important in order to form narrower ground contact polygons. Therefore, the actuators of these joint parts have soft joint characteristics, that is, actuators. As shown in FIG. 13, the servo characteristic of the motor is low, the gain is low, and the phase advance amount is increased in the middle and high ranges, and the motor viscosity is reduced to one third of the maximum value of the motor characteristic shown in FIG. 17B. Set.

  In addition, the actuator of the joint part related to the operation of narrowing the support polygon such as the left and right shoulder pitch, shoulder roll, shoulder yaw, thigh roll, thigh pitch, knee pitch, etc. has intermediate joint characteristics, that is, the actuator motor As shown in FIG. 13, the servo characteristic is low in the low range and low in gain, and the phase advance amount in the middle and high range is increased, and the motor viscosity is maintained at the maximum value of the motor characteristic shown in FIG. Get compliance and prepare for the next action.

  In addition, trunk rolls, trunk pitches, and actuators of joint parts other than those described above have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. While the advance amount is reduced, the motor viscosity shown in FIG. 17A is maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(D) Use both arms to support 4 points and bring the ZMP close to the ground contact surface of the foot. Fix the elbow pitch axis 7 and keep the left and right arms straight, this time the shoulder pitch axis. Actuator A ₄ , trunk pitch axis actuator A ₉ , hip joint pitch axis A ₁₂ , and knee joint pitch axis actuator A ₁₄ are actuated to form a narrower grounding polygon having a closed link posture in which the hand and the left and right knees are grounded. Form. The lower limbs, waist, trunk, and upper limbs constitute a closed link system with respect to the floor (see FIG. 58). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

  At this time, the joint part actuator that performs the operation of searching for the narrowest support polygon such as the trunk roll, trunk pitch, left and right shoulder pitch, shoulder roll, shoulder yaw, thigh roll, thigh pitch, knee pitch, As shown in FIG. 13, the joint characteristics, that is, the servo characteristics of the actuator and the motor are increased in the low range, the low gain and the phase advance amount in the mid-high range, and the motor viscosity is the maximum value of the motor characteristics shown in FIG. Maintaining high-speed response and obtaining compliance above the hard characteristics and below the soft characteristics, the position accuracy is above the soft characteristics and below the hard characteristics, and stable operation in the closed link state Contribute to.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. The motor characteristics shown in FIG. 17A are maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(E) The posture is controlled so that the ZMP falls within the support polygon formed by the ground contact surface of the foot. While keeping the right arm straight, the hand gradually moves toward the sole, which is the other landing point. By approaching, a narrower support polygon is formed, and the ZMP can be moved into a ZMP stable region that can be formed only by the foot. The lower limbs, waist, trunk, and upper limbs constitute a closed link system with respect to the floor surface (see FIG. 59).

  At this time, the joint part actuator that performs the operation of searching for the narrowest support polygon such as the trunk roll, trunk pitch, left and right shoulder pitch, shoulder roll, shoulder yaw, thigh roll, thigh pitch, knee pitch, As shown in FIG. 13, the joint characteristics, that is, the servo characteristics of the actuator and the motor are increased in the low range, the low gain and the phase advance amount in the mid-high range, and the motor viscosity is the maximum value of the motor characteristics shown in FIG. Maintaining high-speed response and obtaining compliance above the hard characteristics and below the soft characteristics, the position accuracy is above the soft characteristics and below the hard characteristics, and stable operation in the closed link state Contribute to.

  In addition to the above, the actuator of the joint part other than the above has a hard joint characteristic, that is, the servo characteristic of the actuator and the motor, as shown in FIG. The motor characteristics shown in FIG. 17A are maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(F) Leave both arms to support two points. With the hands and soles as the ends of the link ends of the contact polygon in contact with the floor, gradually reduce the distance between the hands and the soles. Then, move the ZMP toward the sole. Then, in response to the ZMP entering the ground contact polygon formed by the sole, the link from the shoulder pitch axis 4 to the knee pitch axis 14 is maintained while the ZMP is accommodated in the ground contact polygon. Get up and complete the get-up action by leaving the bed and extending the bed link in the length direction. The left and right legs constitute a closed link system with respect to the floor (see FIG. 60). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

  At this time, in the right and left ankle rolls and ankle pitches, high speed response and compliance are important in order to follow the motion of raising the base body. As shown in FIG. 13, the servo characteristics of the actuator and motor are low, the gain is low, the phase advance amount is high, and the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the left and right ankles can respond quickly and obtain compliance. In addition, the viscosity of the motor increases.

  Also, the actuators of the joint parts related to the arm drive such as the left and right shoulder pitches, shoulder rolls, elbow pitches, etc. have high joint characteristics, that is, the servo characteristics of the actuator motor are high in all bands as shown in FIG. The gain and the phase advance amount in the high band are reduced, and the motor viscosity is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity is maintained at the maximum value of the motor characteristics shown in FIG. 17A.

  In addition, trunk rolls, trunk pitches, and actuators of joint parts other than those described above have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. While the advance amount is reduced, the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG. 17A. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

(G) Transition to the basic posture The posture is controlled in a basic standing posture, and the left and right lower limbs form a closed link system with respect to the floor surface (see FIG. 61). This state can be confirmed from the posture (grounding state) using the posture sensor, own joint angle information, and the force sensor (or contact sensor) of the sole.

  At this time, since the positioning accuracy is important in the joint parts such as the shoulder yaw axis and the shoulder pitch axis, the hard joint characteristics, that is, the servo characteristics of the actuator / motor are shown in FIG. As described above, the gain is high in the entire band and the phase advance amount in the high band is reduced, and the viscosity of the motor is set to the maximum value of the motor characteristics shown in FIG.

  In addition, the actuators in the joint parts of the left and right lower limbs have an intermediate joint characteristic, that is, the servo characteristic of the actuator / motor, as shown in FIG. The motor viscosity shown in FIG. 17A is maintained.

  In addition, trunk rolls, trunk pitches, and actuators of joint parts other than those described above have hard joint characteristics, that is, the servo characteristics of the actuator and motor, as shown in FIG. While the advance amount is reduced, the motor viscosity shown in FIG. 17A is maintained. As a result, the positioning accuracy is prioritized and it is robust against disturbances such as vibration.

  As described above, when the aircraft rises from the prone posture, the actuator characteristics are set so that the low gain is increased, the phase advance amount is decreased, and the joint viscous resistance is increased as shown in FIG. By doing so, highly accurate positioning becomes possible. Therefore, since the accuracy of the operation control is improved in all of (A) to (G), the accuracy of the size of the support polygon can be ensured.

  Further, the actuator characteristics are set so that the low-frequency gain is small, the phase advance amount is large, and the viscous resistance of the joint is small as shown in FIG. And can give high speed responsiveness. Therefore, at the time of the state transition of (A) to (B), (C) to (E), (F) to (G), the movement of the arms and legs and the landing operation are smoothed and the energy consumption is reduced. can do.

  The present invention has been described in detail above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications and substitutions of the embodiments without departing from the gist of the present invention.

  The gist of the present invention is not necessarily limited to a product called a “robot”. That is, as long as it is a mechanical device that performs an exercise resembling human movement using an electrical or magnetic action, the present invention can be applied to products belonging to other industrial fields such as toys. Can be applied.

  In the present specification, the description has been made centering on the motor / actuator as the actuator for driving the joint of the robot, but the gist of the present invention is not limited to this. In addition to motors and actuators that have a rotation axis that directly drives the joint angle, servo gain control is also applied to actuators that drive joints by expanding and contracting the distance of links that connect joints like muscles. In addition, the effects of the present invention can be suitably achieved by controlling the viscosity. Examples of the latter joint drive actuator include a shape memory alloy actuator, a fluid actuator, and a polymer actuator.

  Further, in this specification, a circuit example configured by using a switching element made of a bipolar transistor for switching control of a coil current to a coil of a motor / actuator has been described. However, a MOS-FET or other semiconductor element is used. Those skilled in the art will appreciate that this type of control circuit can be implemented using.

  In short, the present invention has been disclosed in the form of exemplification, and the description of the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims section described at the beginning should be considered.

FIG. 1 is a view showing a state in which a legged mobile robot used for carrying out the present invention is viewed from the front. FIG. 2 is a view showing a state in which a legged mobile robot used for carrying out the present invention is viewed from the rear. FIG. 3 is a diagram schematically illustrating a joint degree-of-freedom configuration included in the legged mobile robot. FIG. 4 is a diagram schematically showing a control system configuration of the legged mobile robot 100. FIG. 5 is a diagram showing the configuration of the servo controller of the actuator. FIG. 6 is a diagram showing the frequency characteristics of the transfer function expression model gain and phase of the motor and the speed reducer shown in FIG. FIG. 7 is a diagram for explaining an example in which a phase compensation band is arbitrarily selected as a design example of phase compensation control in the servo controller shown in FIG. FIG. 8 is a diagram for explaining an example in which the amount of phase compensation is arbitrarily selected as a design example of the phase compensation control in the servo controller shown in FIG. FIG. 9 is a diagram for explaining a design example of a controller that changes the magnitude of the series compensation gain indicated by K in the servo controller shown in FIG. FIG. 10 is a diagram showing open loop characteristics when the servo controller of the actuator is mounted so as to arbitrarily select the frequency band with a constant phase compensation amount as shown in FIG. FIG. 11 is a diagram illustrating a state in which the control of the series compensation gain is further adopted in Example C (s) -3 in which phase lead compensation is performed only in the middle and high range shown in FIG. FIG. 12 is a diagram showing an example in which the gain is set to be high as a whole with respect to the open loop characteristic of the actuator position control system, and the characteristic is set so as to reduce the phase advance amount in a high range. FIG. 13 is a diagram showing an example in which the open loop characteristic of the actuator position control system is set to a characteristic in which a low gain is set in a low range and a phase advance amount is increased in a mid-high range. FIG. 14 is a diagram illustrating a configuration example of an equivalent circuit of a current control circuit for supplying a coil current of a DC motor to which a coil current control mechanism is applied. FIG. 15 is a diagram showing a specific circuit configuration of the additional logic circuit. FIG. 16 is a diagram showing the output characteristics of each transistor control signal of the additional logic circuit when the high-level BRAKE_PWM control signal is input, together with the coil current waveform characteristics and the torque output characteristics. FIG. 17 is a diagram showing the relationship of control areas in which the viscous resistance of the motor is dynamically controlled by the duty ratio of the BRAKE_PWM control signal. FIG. 18 is a diagram illustrating a state in which the legged mobile robot performs a walking motion for each stage. FIG. 19 is a diagram showing a multi-mass point approximation model of the legged mobile robot 100 having the multi-joint degree-of-freedom configuration shown in FIG. FIG. 20 is a flowchart showing a processing procedure for generating a body motion capable of stable walking using ZMP as a stability criterion in the legged mobile robot 100. FIG. 21 is a diagram schematically showing an example in which the body part group is set. FIG. 22 is a diagram showing the position of the center of gravity of the mass M ₇ . FIG. 23 is a flowchart showing a schematic processing procedure of operation control of the airframe during legged work in the legged mobile robot 100. FIG. 24 is a flowchart showing a processing procedure for the legged mobile robot 100 to perform a tipping operation when the foot cannot be planned. FIG. 25 shows a legged mobile robot 100 composed of a plurality of substantially parallel joint axes connected in the height direction, such as a shoulder joint pitch axis 4, a trunk pitch axis 9, a hip joint pitch axis 12, and a knee joint pitch axis 14. It is the figure which showed the operation | movement which models as a link structure and falls down toward a supine posture by driving each joint pitch axis synchronously emphasizing. FIG. 26 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 27 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 28 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 29 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 30 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 31 is a diagram illustrating a process in which the legged mobile robot 100 falls from a standing posture to a supine posture. FIG. 32 is a diagram illustrating a state in which a closed link system is configured by both legs and the floor surface by supporting both legs when the legged mobile robot 100 is in a standing posture. FIG. 33 is a diagram illustrating a state in which an open link is configured with both legs and a floor surface by supporting a single leg when the legged mobile robot 100 is in a standing posture. 34, the legged mobile robot 100 includes a plurality of substantially parallel joint axes connected in the height direction such as the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, the knee joint pitch axis 14, and the like. It is the figure which showed the operation | movement which models as a link structure and falls down toward a prone posture by driving each joint pitch axis synchronously emphasizing. FIG. 35 is a diagram illustrating a process in which the legged mobile robot 100 falls from the standing posture to the prone posture. FIG. 36 is a diagram illustrating a process in which the legged mobile robot 100 falls from the standing posture to the prone posture. FIG. 37 is a diagram illustrating a process in which the legged mobile robot 100 falls from the standing posture to the prone posture. FIG. 38 is a diagram illustrating a process in which the legged mobile robot 100 falls from the standing posture to the prone posture. FIG. 39 is a diagram illustrating a process in which the legged mobile robot 100 falls from the standing posture to the prone posture. FIG. 40 shows a processing procedure for the legged mobile robot 100 to get up by driving the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 in a synchronously enhanced manner. It is a flowchart. FIG. 41 shows how the legged mobile robot 100 rises from a supine posture by driving the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 in a synchronously enhanced manner. It is the figure shown with the joint link model. FIG. 42 is a diagram showing a series of operations in which the legged mobile robot 100 gets up from the supine posture. FIG. 43 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 44 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 45 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 46 is a diagram showing a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 47 is a diagram showing a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 48 is a diagram showing a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 49 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 50 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 51 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 52 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a supine posture. FIG. 53 shows how the legged mobile robot 100 rises by driving the shoulder joint pitch axis 4, the trunk pitch axis 9, the hip joint pitch axis 12, and the knee joint pitch axis 14 in a synchronously enhanced manner. It is the figure shown with the model. FIG. 54 is a diagram showing a state where the legged mobile robot 100 gets up from a prone posture. FIG. 55 is a diagram showing a process in which the legged mobile robot 100 gets up from a prone posture. FIG. 56 is a diagram showing a process in which the legged mobile robot 100 gets up from the prone posture. FIG. 57 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a prone posture. FIG. 58 is a diagram showing a process in which the legged mobile robot 100 gets up from a prone posture. FIG. 59 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a prone posture. FIG. 60 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a prone posture. FIG. 61 is a diagram illustrating a process in which the legged mobile robot 100 gets up from a prone posture.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Neck joint yaw axis 2A ... 1st neck joint pitch axis 2B ... 2nd neck joint (head) pitch axis 3 ... Neck joint roll axis 4 ... Shoulder joint pitch axis 5 ... Shoulder joint roll axis 6 ... Upper arm yaw axis 7 ... Elbow joint pitch axis 8 ... Wrist joint yaw axis 9 ... Trunk pitch axis 10 ... Trunk roll axis 11 ... Hip joint yaw axis 12 ... Hip joint pitch axis 13 ... Hip joint roll axis 14 ... Knee joint pitch axis 15 ... Ankle joint pitch Axis 16 ... Ankle joint roll axis 30 ... Head unit, 40 ... Trunk unit 50 ... Arm unit, 51 ... Upper arm unit 52 ... Elbow joint unit, 53 ... Forearm unit 60 ... Leg unit, 61 ... Thigh unit 62 ... knee joint unit, 63 ... shin unit 80 ... control unit, 81 ... main control unit 82 ... peripheral circuit 91, 92 ... grounding confirmation sensor 93, 94 ... acceleration sensor 95 ... posture sensor 9 ... acceleration sensor 100 ... legged mobile robot

Claims (25)

In a robot apparatus including at least a torso and movable legs and including a plurality of joints,
The movable leg includes at least a knee pitch and an ankle pitch joint,
The servo controller for the position control system of the actuator that drives each joint has a low gain in the low range and a large phase advance amount in the middle and high range, and a high gain in the entire range and a small phase advance amount in the high range. The actuator motor has a state where the viscous resistance is small and a state where it is large,
The robot apparatus is:
Actuator characteristic control means for combining the gain and phase compensation control of the servo controller of the actuator position control system for driving each joint and the control of the viscous resistance of the actuator motor;
In response to the fact that it is impossible to plan the foot part, it comprises a body motion control means at the time of the fall, which starts the fall motion, and controls the body motion at the time of the supine fall,
The actuator characteristic control means sets at least the knee pitch joint as a joint related to the position energy control and drives the joint related to the position energy control in a stage from the start of the overturning operation to the landing of the aircraft. The actuator servo controller to reduce the viscous resistance of the joint by increasing the phase advance amount in the low range and low gain and in the middle and high range, and reducing the viscous resistance of the actuator and motor,
A robot apparatus characterized by that. The actuator characteristic control means further sets an ankle pitch joint as a joint related to position energy control at the time of starting the overturning operation, and lowers an actuator servo controller for driving the joint related to position energy control. In addition to increasing the phase advance amount in the middle and high range with low gain in the region, the viscous resistance of the joint is reduced by reducing the viscous resistance of the actuator motor.
The robot apparatus according to claim 1. The actuator characteristic control means sets all joints of the movable leg to joints related to position energy control at the time of landing of the airframe, and performs servo control of an actuator for driving the joints related to position energy control. Reduce the viscosity resistance of the joint by reducing the viscous resistance of the actuator and motor, while increasing the phase advance amount in the low range with low gain and medium and high range,
The robot apparatus according to claim 1. The torso includes one or more joints;
The actuator characteristic control means sets all joints of the fuselage as joints related to potential energy control at the time of landing of the fuselage, and performs servo control of an actuator for driving the joints related to positional energy control Reduce the viscosity resistance of the joint by reducing the viscous resistance of the actuator and motor, while increasing the phase advance amount in the low range with low gain and medium and high range,
The robot apparatus according to claim 3. The actuator characteristic control means sets a phase advance in a low range and a low gain and in a middle and high range at a stage where the overturning operation is completed and the impact is eliminated. While increasing the amount, increase the viscous resistance of the joint by increasing the viscous resistance of the actuator motor.
The robot apparatus according to claim 1. The robot apparatus further includes a head connected to the trunk via a neck joint,
In the stage from the start of the overturning operation to the landing of the airframe, the actuator characteristic control means sets the actuator servo controller for driving the neck joint with a high gain in all bands and a phase advance in the high band. Increase the viscous resistance of the joint by reducing the amount and increasing the viscous resistance of the actuator and motor,
The robot apparatus according to claim 1. In a robot apparatus including at least a torso, an arm, and a movable leg and including a plurality of joints,
The movable leg includes at least a knee pitch and an ankle pitch joint, and the arm includes an elbow joint,
The servo controller for the position control system of the actuator that drives each joint has a low gain in the low range and a large phase advance amount in the middle and high range, and a high gain in the entire range and a small phase advance amount in the high range. The actuator motor has a state where the viscous resistance is small and a state where it is large,
The robot apparatus is:
Actuator characteristic control means for combining the gain and phase compensation control of the servo controller of the actuator position control system for driving each joint and the control of the viscous resistance of the actuator motor;
In response to the fact that it is impossible to plan the foot part, it comprises a body motion control means at the time of falling, which controls the body motion at the time of lying down prone to wear the arm,
In the stage from the start of the overturning operation to the landing of the aircraft, the actuator characteristic control means sets the servo controller of the actuator for driving the elbow joint in a low range with a low gain and a phase advance in the mid-high range. Decrease the viscous resistance of the joint by increasing the amount and decreasing the viscous resistance of the actuator / motor,
A robot apparatus characterized by that. The actuator characteristic control means sets the knee pitch joint and the ankle pitch joint as joints related to positional energy control at the time of starting the overturning operation, and drives an joint related to the positional energy control. Servo controller with low gain, low gain and large phase advance amount in mid-high range, and lowering the viscous resistance of the actuator and motor to reduce the viscous resistance of the joint,
The robot apparatus according to claim 7. The movable leg further comprises a thigh pitch joint,
In response to the ZMP deviating from the ZMP stable region formed only by the sole, the body operation control means during the overturn starts the overturning operation while maintaining the ZMP in the support polygon, and performs the overturning operation. At the time of starting, the thigh pitch joint is set to a joint related to stable region control,
The actuator characteristic control means increases the phase advance amount in the low range and the low gain and the phase advance amount in the middle and high range of the servo controller of the actuator for driving the thigh pitch joint set to the joint related to the stable region control, Increase the viscous resistance of the joint by increasing the viscous resistance of the actuator motor.
The robot apparatus according to claim 7. The actuator characteristic control means sets the thigh pitch joint as a joint related to potential energy control at the time when the foot of the movable leg serving as a support leg leaves the floor by further overturning motion, and performs the potential energy control. The servo controller of the actuator for driving the joints involved has a low gain in the low range and a large phase advance amount in the mid and high range, and the viscous resistance of the joint is reduced by reducing the viscous resistance of the actuator / motor. To switch,
The robot apparatus according to claim 9. The actuator characteristic control means sets all joints of the movable leg to joints related to position energy control at the time of landing of the airframe, and performs servo control of an actuator for driving the joints related to position energy control. Of the actuator for driving the elbow joint by reducing the viscous resistance of the joint by reducing the viscous resistance of the actuator / motor, Servo controller with low gain, low gain and large phase advance amount in mid-high range, and lowering the viscous resistance of the actuator and motor to reduce the viscous resistance of the joint,
The robot apparatus according to claim 7. The torso includes one or more joints;
The actuator characteristic control means sets all joints of the fuselage as joints related to potential energy control at the time of landing of the fuselage, and performs servo control of an actuator for driving the joints related to positional energy control Reduce the viscosity resistance of the joint by reducing the viscous resistance of the actuator and motor, while increasing the phase advance amount in the low range with low gain and medium and high range,
The robot apparatus according to claim 11. The actuator characteristic control means sets a phase advance in a low range and a low gain and in a middle and high range at a stage where the overturning operation is completed and the impact is eliminated. While increasing the amount, increase the viscous resistance of the joint by increasing the viscous resistance of the actuator motor.
The robot apparatus according to claim 7. The robot apparatus further includes a head connected to the trunk via a neck joint,
In the stage from the start of the overturning operation to the landing of the airframe, the actuator characteristic control means sets the actuator servo controller for driving the neck joint with a high gain in all bands and a phase advance in the high band. Increase the viscous resistance of the joint by reducing the amount and increasing the viscous resistance of the actuator and motor,
The robot apparatus according to claim 7. In a robot apparatus including a link structure including a plurality of links including at least a trunk, an arm, and a movable leg, connected by a plurality of joints, and including a center-of-gravity link.
The arm includes a joint of shoulder pitch, shoulder roll, and elbow pitch, and the movable leg includes a joint of at least a thigh, a knee pitch, and an ankle pitch,
The servo controller for the position control system of the actuator that drives each joint has a low gain in the low range and a large phase advance amount in the middle and high range, and a high gain in the entire range and a small phase advance amount in the high range. The actuator motor has a state where the viscous resistance is small and a state where it is large,
The robot apparatus is:
Actuator characteristic control means for combining the gain and phase compensation control of the servo controller of the actuator position control system for driving each joint and the control of the viscous resistance of the actuator motor;
A rising motion control means for controlling the rising motion from the sleeping posture of the aircraft,
The rising motion control means includes
A first means for searching for a narrowest support polygon included in a ground contact polygon formed by ends of a plurality of aircraft in contact with the floor surface in an on-floor posture in which at least three or more links are in contact with the floor;
Two or more links that do not participate in the narrowest support polygon among the links constituting the ground polygon are left and the one or more floor links are bent to end the end of the link to narrow the ground A second means for forming a square;
It is determined whether ZMP can be set for the ground polygon formed by the second means, and when it is determined that ZMP cannot be set, the third means for retrying formation of a narrower support polygon by the second means. Means,
In response to the determination that the third means can set the ZMP, the ZMP is moved to the grounding polygon, and the center of gravity link can be removed from the floor or the ZMP is moved into a stable ZMP area that can be formed by only the foot. It is further judged whether or not the newly formed support polygon is sufficiently narrow, and if the support polygon is still not sufficiently narrow, the support polygon can be moved by moving the landing point. A fourth means for retrying the formation of a narrower support polygon by the second means after reducing
In response to determining that the support polygon is sufficiently narrow by the fourth means, the center-of-gravity link is removed from the floor while the ends of both link ends of the support polygon are in contact with each other, and both link ends are attached. While maintaining the ZMP in the support polygon formed by the floor link, the distance between the ends of the link ends forming the support polygon is reduced, and the ZMP is moved to the other end of the link structure. In response to the ZMP having entered the ground polygon formed by the second predetermined number or less of the floor contact links from the other end of the link structure, the ZMP remains accommodated in the ground polygon. A fifth means for raising the robot apparatus by leaving the first predetermined number of links from one end of the link structure and extending the bed leaving link in the length direction;
When the first means searches for the narrowest support polygon, the actuator characteristic control means has a high-gain servo controller for the actuator that drives each joint of the arm in preparation for a rising motion in all bands. Increase the viscous resistance of the joint by reducing the amount of phase advance at high frequencies and increasing the viscous resistance of the actuator and motor.
A robot apparatus characterized by that. At the time of getting up from the attitude of the aircraft and the prone position,
The actuator characteristic control means is a servo controller for an actuator that drives each joint of a movable leg used as a support leg by the second and fourth means. And increase the viscous resistance of the joint by increasing the viscous resistance of the actuator and motor.
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft,
The actuator characteristic control means drives the thigh joint of the free leg during a period until the second means contacts the floor to form a narrower grounding polygon using a movable leg used as a free leg. The actuator servo controller has a high gain in the entire band and a small phase advance amount in the high band, and the viscous resistance of the actuator motor is increased to increase the viscous resistance of the joint.
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft,
The actuator characteristic control means may be an actuator that drives a joint of a portion where the movable leg that becomes the support leg is landed when the fifth means performs the rising operation with the arm and the movable leg supported. Servo controller with low gain, low gain and large phase advance amount in mid-high range, and lowering the viscous resistance of the actuator and motor to reduce the viscous resistance of the joint,
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft,
The actuator characteristic control means leaves the two or more links that are not involved in the narrowest support polygon among the links in which the second means constitutes the ground polygon, and bends the one or more floor links to bend the link end. During the period from when the end of the arm is landed to form a narrower grounding polygon, the servo controller of the actuator that drives each joint of the part related to the rising motion is low gain and low gain, and the phase advance in the mid and high ranges While increasing the amount, increase the viscous resistance of the joint by increasing the viscous resistance of the actuator and motor,
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft,
The actuator characteristic control means lowers the servo controller of the actuator that drives each joint of the support leg when the fifth means gets up the arm and moves up to the support state of the movable leg. In addition to increasing the phase advance amount in the middle and high range with a low gain in the region, the viscosity resistance of the joint is increased by increasing the viscous resistance of the actuator motor.
The robot apparatus according to claim 18. At the time of getting up from the attitude of the aircraft and the prone position,
The actuator characteristic control means leaves the two or more links that do not participate in the narrowest support polygon among the links in which the second means constitutes the contact polygon, and bends the one or more floor links to bend the link. The servo controller of the actuator that drives the joint used to land the end of the end to form a narrower grounding polygon increases the amount of phase advance in the low range and low gain, and in the middle and high range. -Increasing the viscous resistance of the joint by increasing the viscous resistance of the motor,
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft and the prone position,
The actuator characteristic control means increases the phase advance amount in the low and low gain and the medium and high ranges of the servo controller of the actuator that drives the joint used by the fourth means to narrow the support polygon. Increasing the viscous resistance of the joint by increasing the viscous resistance of the actuator motor
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft and the prone position,
The actuator characteristic control means includes a servo controller for an actuator that drives a shoulder joint that operates with priority on positioning during the period until the second means contacts the floor to form a narrower ground polygon. Increase the viscous resistance of the joint by increasing the viscous resistance of the actuator / motor while reducing the amount of phase advance in the high band with high gain in the band,
The robot apparatus according to claim 15. At the time of getting up from the attitude of the aircraft,
The actuator characteristic control means includes an ankle heading toward the floor of the free leg during a period until the second means touches the floor to form a narrower grounding polygon using a movable leg used as a free leg. The servo controller of the actuator that drives the joint of the actuator has a low gain in the low range and a large phase advance amount in the middle and high ranges, and the viscous resistance of the joint is reduced by reducing the viscous resistance of the actuator motor.
The robot apparatus according to claim 15. The torso further comprises a trunk joint,
When getting up from the prone posture of the aircraft,
The actuator characteristic control means leaves the two or more links that do not participate in the narrowest support polygon among the links in which the second means constitutes the contact polygon, and bends the one or more floor links to bend the link. When landing the end of the end to form a narrower grounded polygon, or when the fourth means uses the trunk joint to move the ZMP to the grounded polygon, the trunk joint is with increasing amount of phase lead and the mid-high range at low gain servo controller of the actuator for driving the low range, to increase the viscous resistance of the joint by increasing the viscosity resistance of the actuator motor,
The robot apparatus according to claim 15.

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