JP2006095648A - Leg-type moving robot and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize efficient gliding by suitably utilizing a support leg replacement time. <P>SOLUTION: Basically similarly to a control algorithm in the bipedal case, support legs are switched alternately between right and left movable legs through the both-leg support period. When the one-leg gliding period and switching between the gliding legs occurs, the locus of ZMP is controlled to keep the contact between the passive wheel and the floor surface in a stable surface contact. In switching the support legs, it is necessary to keep the consistency about the gliding speed and the gliding direction at the foot part and the position relationship between both soles at the floor surface between the supporting leg and the grounding leg. It is, however, possible to eliminate the need of keeping the consistency by instantaneously replacing the support legs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a legged mobile robot having a plurality of movable legs and a method for controlling the legged mobile robot, and more particularly to a leg and a wheel hybrid type legged mobile robot having both characteristics of a legged movement and a wheel type movement. And a control method thereof.

  More specifically, the present invention relates to a legged mobile robot and a control method thereof, which improve running performance in addition to ground adaptability by legs by attaching wheels to the feet of each movable leg of a biped walking robot. The present invention relates to a legged mobile robot that suitably utilizes a support leg replacement period to realize efficient or stable sliding and a control method thereof.

  A mechanical device that performs a movement resembling human movement using an electrical or magnetic action is called a “robot”. Many of them were industrial robots such as manipulators and transfer robots for the purpose of automating and unmanned production work in factories.

  In the future, in order for the robot to perform various human tasks and further penetrate deeply into the human living space, it is preferable that the movable range of the robot is substantially the same as that of the human. However, most of the human work space and living space are formed according to the human body mechanism and behavioral style of biped upright walking, and the current mechanical system using wheels and other driving devices as moving means moves. There are many barriers. Therefore, recently, research and development on legged mobile robots that imitate the body mechanism and movement of animals such as humans who perform biped upright walking are progressing, and the expectation for practical use is also increasing (for example, Patent Document 1). checking).

  Leg-type movement with two legs standing upright is unstable and difficult to control posture and walking, compared to crawler type, four-legged or six-legged type, etc. Can move.

(1) High selectivity of the toe position with respect to the unevenness formed on the moving surface (2) Selective grounding or movement by discontinuous grounding (3) Flexible change of grounding state by stepping action

  In other words, the legged mobile robot can cope with uneven walking surfaces such as rough terrain and obstacles on the work path, and discontinuous walking surfaces such as stairs and ladders, etc. Flexible movement work can be realized. This is also why the practical application of legged mobile robots is highly expected.

  In many cases, ZMP (Zero Moment Point) is used as a norm for determining the stability of walking for posture stability control of a legged mobile robot. “ZMP” as used herein refers to a point on the floor where the moment due to floor reaction force during walking is zero. 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 mechanical reasoning, there is a point where the pitch axis and roll axis moments become zero inside the support polygon formed by the sole contact point and the road surface, that is, ZMP (for example, see Non-Patent Document 1). ). In addition, the posture of the robot becomes more stable in the posture where the support polygon becomes wide.

  Target ZMP control has been successful on a real machine by planning the motion to be in dynamic balance at every moment. The biped walking pattern generation based on the ZMP norm has advantages such 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. In addition, using ZMP as a stability determination criterion means that a trajectory is treated as a target value in motion control instead of force, and thus technically feasible.

  On the other hand, a legged mobile robot has high ground adaptability, but has a problem that it is inferior to a wheeled mobile robot in terms of moving speed and efficiency. This is because the walking motion involves reciprocation of each leg, energy conversion efficiency is not so high, and a speed sufficient for a powerful drive system such as an actuator cannot be obtained. Regarding legged mobile robots, the speed of movement when moving on a relatively flat road has been discussed previously. For this reason, research is being conducted on a so-called hybrid type of a leg-wheel hybrid that has the characteristics of both leg-type movement and wheel-type movement.

  As a mobile robot using wheels, for example, a six-leg traveling vehicle for extreme work (for example, see Non-Patent Document 2) or a moving body (for example, see Non-Patent Document 3) for entering a disaster site. In addition, if the crawler is also regarded as a wheel in a broad sense from the viewpoint of using a continuous endless track, COMET-III (for example, see Non-Patent Document 4) developed for the purpose of removing landmines can be cited. .

  These moving bodies use active wheels having driving force as wheels. On the other hand, a legged walking machine generally has many degrees of freedom for walking, and the body mass tends to increase. In addition, when an actuator for driving the wheel is mounted, the mass increases unnecessarily, and as a result, the performance of the walking machine is constrained.

  Therefore, a hybrid method for walking machines using passive wheels with a simple mechanism and a small increase in mass has been proposed.

  For example, there has been proposed a legged mobile robot that can realize a moving work that is more dynamic and faster than normal walking motion by wearing roller skates (see, for example, Patent Document 2). . The robot apparatus in this case is a biped walking type mobile robot composed of two movable legs and an upper body, and realizes various operation patterns by controlling the whole body motion using the lower limbs and the upper body. be able to. In the case of a robot apparatus wearing this type of roller skates, the following matters are assumed. That is,

(1) The passive wheel is always parallel to the leg joint pitch axis.
(2) In the sliding method, the legs are made to swing freely like walking.

  A sliding unit having a predetermined sliding direction is detachably attached to the bottom of each movable leg of the legged mobile robot. If the passive wheel of the sliding unit is held parallel to the leg joint pitch axis, the direction of travel cannot be changed during the support period for both feet, so the propulsion direction can only be changed when the support leg is switched, is not. Accordingly, the moving speed can be maintained while matching the sliding unit with the sliding direction, and braking can be performed by making the sliding unit different from the sliding direction. For example, braking can be performed by tilting the wheel into a C-shape like a ski bogen in the ground contact period of both legs.

  A passive wheel is composed of a relatively simple mechanism and is lightweight and inexpensive, but it does not have propulsion power itself. As a method for imparting a propulsive force to a passive wheel attached to a foot tip, a “roller walker” using a principle similar to that of roller skate can be cited (for example, see Non-Patent Document 5).

  In the propulsion by the passive wheel, the rolling direction of the wheel has a small coefficient of friction, and the friction in the axial direction is large. By using such anisotropy of the drag, propulsion by passive wheels is realized. For example, by using the rotation around the yaw axis at the base of the left and right legs, the distance in the axial direction between the left and right wheels expands and contracts while the left and right wheels each have an inclination in the X direction. At this time, since the friction in the axial direction is large, the frictional force generated in the axial direction of the wheel is released by the rolling of the wheel and is converted into a propulsive force in the X direction.

Here, in order to convert the frictional force in the axial direction of the wheel into rotation of the wheel, it has a mechanism for rotating the rolling direction of the wheel around the yaw axis, and the rolling direction is non-orthogonal with respect to the frictional force applied to the wheel. There must be. Further, the angle θ _G (referred to as the glide angle) formed by the rolling direction of the wheel and the propulsion direction (or the main traveling direction of the robot) corresponds to the reduction ratio of the gear. Therefore, it is possible to generate a large driving force to the propulsion direction of the device from becoming slow I mean a large angle by the glide angle theta _G. Conversely, by providing a small angle with the glide angle theta _G, it is a small driving force, it is possible to promote the robot at a high speed (e.g., see non-patent document 6 and non-patent document 7).

  As described above, according to the roller walker, it is possible to realize high-speed propulsion that exceeds the maximum speed that the tip of the foot produces, adjustment of the reduction ratio by changing the leg trajectory, and the like.

  However, the roller walker method basically assumes a quadruped walking robot, and this method cannot be applied to a biped robot. In addition, since support by both legs is always assumed and switching of the support legs is not included, the moving road surface is limited to a relatively flat road, and even though it is a legged robot, the ground adaptability cannot be sufficiently exhibited.

JP 2001-129775 A JP 2001-138272 A "Legged LOCATION ROBOTS" written by Miomir Vukobratovic (Ichiro Kato's "Walking Robot and Artificial Feet" (Nikkan Kogyo Shimbun)) N. Kimura, T. Kamigaki, N. Suzuki, A. Nishikawa and N. Yamamoto: "Locomotion Mechanism and Control Architecture for Disaster Preventing Robot" '91 ISART pp.375-380 (1991) H.Adachi, N.Koyachi, T.Arai, A.SHimizu and Y.Nogami: "Mechanism and Control of a Leg-Wheel Hybrid Mobile Robot", International Conference on Intelligent Robots and Systems Proc., Pp.1792-1797 ( 1999) http://mec2.tm.chiba-u.jp/~nonami/ G. Endo, S. Hirose: "Study on Roller-Walker (Multi-mode Steering Control and Self-contained Locomotion", IEEE International Conference on Robotics and Automation, pp. 2808-2814 (2000) Gen Endo: “Study on glide propulsion in cord-like active vehicle and leg-wheel hybrid vehicle”, Tokyo Institute of Technology Graduate School of Science and Engineering, Department of Mechanical Physics Engineering, pp.8-10 (2000) Gen Endo: “Study on Glide Propulsion in Active Active Vehicles and Leg-Wheel Hybrid Vehicles”, Tokyo Institute of Technology Graduate School of Science and Engineering, Department of Mechanical Physics Engineering, pp.80-87 (2000)

  An object of the present invention is to provide an excellent leg-type mobile robot of a leg and wheel hybrid type having both characteristics of a leg-type movement and a wheel-type movement, and a control method thereof.

  A further object of the present invention is to provide an excellent legged mobile robot capable of improving running performance in addition to ground adaptability by legs by attaching wheels to the feet of each movable leg of a biped walking robot and its control. It is to provide a method.

The present invention has been made in consideration of the above problems, and is a legged mobile robot including a trunk and left and right movable legs connected to the trunk,
A passive wheel mechanism comprising a plurality of rotatably supported passive wheels attached to the sole of the movable leg;
An operation control means for controlling at least the operation of the movable leg,
The motion control means includes a sliding control for controlling a sliding speed and a sliding direction during sliding using the passive wheel mechanism while alternately switching a supporting leg between the left and right movable legs, and the legged movement during the sliding. Execute posture stability control that controls the posture stability of the robot based on a predetermined stability criterion,
This is a legged mobile robot.

  The legged mobile robot has excellent ground adaptability, and particularly on rough terrain, it can exhibit a movement capability that cannot be realized in other mobile climate forms. However, there is a problem of low energy efficiency with respect to speed on a flat moving surface.

  On the other hand, the legged mobile robot according to the present invention realizes a hybrid type movement having both characteristics of a leg type movement and a wheel type movement by detachably attaching a passive wheel mechanism to the foot. can do. Further, the wheel can passively obtain a propulsive force by the operation of the foot and does not include an actuator for driving the wheel, so that the total weight does not need to be increased.

  A wheel mechanism composed of one or a plurality of wheels is attached to the tip of the movable leg. It is assumed that all wheel mechanisms are composed of passively supported wheels, and the friction characteristics of each rotating shaft are adjusted. Based on the wheel configuration, the frictional characteristics of the foot around the X, Y, and yaw axes can be adjusted. In addition to adjusting the cross-sectional shape and physical properties of the wheel, and adjusting the attitude of the wheel to the main body, in addition to the friction characteristics, the geometric grounding state with respect to the grounding surface is adjusted, and the motion performance of the robot device such as propulsion performance and turning performance Can be improved. The passive wheel mechanism attaches each passive wheel so that surface contact is possible in which two or more passive wheels contact the moving surface.

  When a passive wheel mechanism is provided on the foot to perform a sliding motion, basically, the support leg is supported between the left and right movable legs via a both-leg support period, as in the control algorithm for biped walking. Switch alternately. When there is a one-leg sliding period or sliding leg switching, the trajectory of the ZMP is controlled to keep the contact between the passive wheel and the floor surface in a stable surface contact.

  When the support legs are exchanged in the both-leg support period, it is necessary to maintain consistency between the support legs and the landing legs in terms of the sliding speed and direction of the foot, and the positional relationship between the soles on the floor. If at least one of the sliding speed or the sliding direction is extremely different between the two legs, a fall is caused.

  However, the processing for achieving this consistency has a high calculation load and causes an increase in cost. Therefore, by changing the support legs instantaneously, i.e., by switching the support legs alternately between the left and right movable legs without passing through the both-leg support period or via the extremely short both-leg support period, It is also possible to eliminate the need to maintain consistency in the sliding direction and the positional relationship between the soles on the floor.

  Further, in the support leg replacement period, a large kicking stroke may be obtained with a relatively narrow joint movable range by making the trunk height as low as possible. In this case, a large joint movable range is not necessary, and a large kicking operation is possible even when the joint movable range is limited.

  The passive wheel mechanism of the sole enables surface grounding in which two or more passive wheels touch the moving surface, and line grounding or point grounding in which only some passive wheels arranged in the sliding direction touch the moving surface. So that each passive wheel is attached. When the support leg is switched to the free leg during the support leg replacement period, a larger stroke can be obtained even when the range of motion of the joint is limited by leaving the floor via line contact or point contact. be able to.

  Also, to increase the kicking stroke in skating, fully extend the knee of the free leg (kick leg), that is, to extend the knee to the maximum when the support leg is switched to the free leg during the support leg replacement period. It is effective to do. In this case, it is possible to land on a range that cannot be reached with the knee bent.

  In addition, in a legged mobile robot to which a sliding means such as a passive wheel mechanism is applied, it is not possible to maintain a stopped state simply by executing a standing posture, and there is a possibility of sliding in a standing posture. Therefore, when the sliding operation is stopped or braked, the movement stopping control by the passive wheel mechanism and the posture stability control based on a predetermined stability determination criterion are simultaneously performed.

  The passive wheel mechanism attached to the soles of the left and right movable legs does not apply a frictional force in the rolling direction, but a high frictional force is applied in the orthogonal direction (that is, the frictional force in the rolling direction is compared with the orthogonal direction. Configured to be smaller). Therefore, the movement of the passive wheel mechanism can be restrained by making the rolling directions of the passive wheel mechanisms of the left and right movable legs non-parallel during the restraining operation.

  The passive wheel mechanism, for example, supports the passive wheel rotatably at four locations, front and rear, and left and right, such that the front and rear direction is the rolling direction. In this case, it is possible to determine a passive wheel that mainly slides by controlling the posture of the foot on the left and right movable legs and adjusting the distribution of the vertical floor reaction force applied to the four passive wheels.

  The vertical floor reaction force applied to the passive wheel on the toe side is made larger than the vertical floor reaction force applied to the passive wheel on the heel side to perform toe sliding that slides on the passive wheel on the toe side, or applied to the passive wheel on the heel side The vertical floor reaction force can be made larger than the vertical floor reaction force applied to the toe-side passive wheel, and the kite can be slid by the passive wheel on the heel side.

  In addition, the left and right movable legs are toed or toe-slided together so that the rotating shafts of the left and right passive wheels cross each other at the desired turning center (or the side turning due to centrifugal force is taken into consideration) The rotating shafts of the left and right passive wheels that slide at the corrected points cross each other), so that the turning operation can be performed while both legs are grounded. Compared with turning by one-leg grounding, the support polygon is wider, so that posture stability during turning can be easily maintained.

  ADVANTAGE OF THE INVENTION According to this invention, the leg-type mobile robot which has the characteristics of both a leg-type movement and a wheel-type movement, and the leg-wheel hybrid type excellent leg-type mobile robot, and its control method can be provided.

  Further, according to the present invention, an excellent legged mobile robot capable of improving running performance in addition to ground adaptability by legs by attaching wheels to the legs of each movable leg of a biped walking robot and its A control method can be provided.

  Further, according to the present invention, it is possible to provide an excellent legged mobile robot and its control method that can realize efficient or stable sliding by suitably utilizing the support leg replacement period.

  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. Configuration of Robot Device In the present invention, a target command value (angle, torque, actuator gain, etc.) is generated by generating a static motion and real-time motion for each control cycle inside the robot device, having a plurality of joints connected to the body. Is assumed to be provided to each joint actuator (or a device corresponding to joint drive).

  FIG. 1 and FIG. 2 show a state in which the “humanoid” or “humanoid” robot apparatus 100 used for carrying out the present invention is viewed from the front and the rear. As shown in the figure, the robot apparatus 100 includes a torso, a waist, a head, left and right upper limbs, and left and right lower limbs that perform legged movement, for example, a control built in the torso. The operation of the robot apparatus is comprehensively controlled by a unit (not shown).

  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 robot apparatus 100 configured as described above can realize bipedal walking by whole body cooperative operation control by a control unit (not shown in FIGS. 1 and 2). 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 control unit includes a controller (main control unit) that processes drive control of each joint actuator constituting the robot device 100 and external input from each sensor (described later), and a housing in which a power supply circuit and other peripheral devices are mounted. Is the body. In addition, the control unit may include a communication interface and a communication device for remote operation.

  The walking control in the legged mobile robot 100 is also realized by, for example, planning a target trajectory of the lower limb in advance using ZMP as a stability determination criterion and correcting the planned trajectory in each of the above-described periods. In this case, 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.

  Alternatively, at least a part of the movable parts of the whole body, such as the left and right legs of the legged mobile robot 100, is regarded as a physical vibrator, and the physical vibrator is changed according to the internal state and the external environment obtained based on the sensor output. The phase can be generated mathematically by operation to achieve global stability of the aircraft and to adaptively handle unknown disturbances.

  FIG. 3 schematically shows the joint degree-of-freedom configuration of the robot apparatus 100. As shown in the figure, the robot apparatus 100 includes an upper limb that includes two arms and a head 1, a lower limb that includes two legs that realize a moving operation, and a trunk that connects the upper limb and the lower limb. And a structure having a plurality of limbs composed of the waist.

  The neck joint (Neck) that supports the head has four degrees of freedom: a neck joint yaw axis 101, a neck joint pitch axis 102A, a head pitch axis 102B, and a neck joint roll axis 3.

  In addition, each arm portion has, as degrees of freedom, a shoulder joint pitch axis 104 in the shoulder (Shoulder), a shoulder joint roll axis 105, an upper arm yaw axis 6, an elbow joint pitch axis 107 in the elbow (Elbow), and a wrist ( Wrist) is composed of a wrist joint yaw axis 108 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 109 and a trunk roll axis 110.

  In addition, each leg constituting the lower limb includes a hip joint yaw axis 111 at the hip joint (Hip), a hip joint pitch axis 112, a hip joint roll axis 113, a knee joint pitch axis 114 at the knee (Knee), and an ankle (Ankle). The ankle joint pitch axis 115, the ankle joint roll axis 116, and the foot portion.

  However, the robot apparatus 100 does not have to be equipped with all the above-described degrees of freedom or is not limited to this. It goes without saying that the degree of freedom, that is, the number of joints, can be increased or decreased as appropriate in accordance with design / manufacturing constraints and required specifications.

  Each degree of freedom of the robot apparatus 100 as described above is actually mounted using a rotary actuator, and motion control is performed based on these rotational position controls. These joint actuators must be small and light because of the need to eliminate extra bulges in appearance and approximate human body shape, and to perform posture control on unstable structures such as biped walking. Is preferred.

  In the present embodiment, a small AC servo actuator of a type directly connected to a gear and having a control board on which a servo control system, a power supply system, and a sensor system circuit are mounted in a motor unit is mounted. The sensor in the motor unit includes an angle / position sensor for detecting the rotational position or joint position for servo control, an acceleration sensor or gyro sensor for posture stability control (eg, ZMP equation parameter acquisition), abnormal state Examples include a torque sensor for detection and a current detection sensor. Further, by adopting a reduced speed gear as a direct connection gear of the actuator / motor, the passive characteristics of the drive system required for the robot 100 of the type that places importance on physical interaction with humans are obtained. This type of AC servo actuator is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 2000-299970 and 2004-181613, which have already been assigned to the present applicant.

  FIG. 4 schematically shows a control system configuration of the robot apparatus 100. As shown in the figure, the robot apparatus 100 includes each of the mechanism units 130, 140, 141, 150R / L, and 160R / L expressing human limbs, and adaptive control for realizing a cooperative operation between the mechanism units. (Where R and L are suffixes indicating right and left, and so on).

  The overall operation of the robot apparatus 100 is comprehensively controlled by the control unit 180. The control unit 180 exchanges data and commands between the main control unit 181 including 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 182 includes an interface (none of which is shown).

  The peripheral circuit 182 referred to here is an interface for connecting an external peripheral device, a charging station (not shown), and other peripheral devices connected via a cable or radio in addition to peripheral devices mounted on the robot apparatus.・ Include connectors.

  In realizing the present invention, the installation location of the control unit 180 is not particularly limited. Although it is mounted on the trunk unit 140 in FIG. 4, it may be mounted on the head unit 130. Alternatively, the control unit 180 may be disposed outside the robot apparatus 100 so as to communicate with the robot apparatus 100 main body by wire or wirelessly.

Each degree of freedom of joint in the robot apparatus 100 shown in FIG. 3 is realized by a corresponding actuator. That is, the head unit 30 includes a neck joint yaw axis actuator M ₁ representing the degree of joint freedom of the neck joint yaw axis 101, neck joint pitch axis 102, and neck joint roll axis 103, and neck joint pitch axis actuator M _2A. A head pitch axis actuator M _2B and a neck joint roll axis actuator M ₃ are provided.

The trunk unit 140 is provided with a trunk pitch axis actuator M ₉ and a trunk roll axis actuator M ₁₀ that express the degree of freedom of joints of the trunk pitch axis 109 and the trunk roll axis 110. .

Further, the arm unit 150R / L is subdivided into an upper arm unit 151R / L, an elbow joint unit 152R / L, and a forearm unit 153R / L, but the shoulder joint pitch axis 104, shoulder joint roll axis 105, upper arm Shoulder joint pitch axis actuator M ₄ , shoulder joint roll axis actuator M ₅ , upper arm yaw axis actuator M ₆ , elbow joint pitch representing the degree of freedom of each of the yaw axis 106, elbow joint pitch axis 107, and wrist joint yaw axis 108. An axis actuator M ₇ and a wrist joint yaw axis actuator M ₈ are provided.

The leg unit 160R / L is subdivided into a thigh unit 161R / L, a knee unit 162R / L, and a shin unit 163R / L, but the hip joint yaw axis 111, hip joint pitch axis 112, hip joint The hip joint yaw axis actuator M ₁₁ , the hip joint pitch axis actuator M ₁₂ , and the hip joint roll axis actuator M ₁₃ representing the joint degrees of freedom of the roll axis 113, knee joint pitch axis 114, ankle joint pitch axis 115, and ankle joint roll axis 116. A knee joint pitch axis actuator M ₁₄ , an ankle joint pitch axis actuator M ₁₅ , and an ankle joint roll axis actuator M ₁₆ are provided.

  For each mechanism unit such as the head unit 130, the trunk unit 140, the arm unit 150, and each leg unit 160, sub-control units 135, 145, 155, and 165 for actuator drive control are disposed.

  An acceleration sensor 196 and a posture sensor 195 are disposed on the waist 141. The acceleration sensor 196 is disposed in each XYZ axial direction. Further, by providing an acceleration sensor 196 on the waist 141, the waist, which is a part with a large mass manipulated variable, is set as a control target point, and the posture and acceleration at that position are directly measured, and posture stabilization based on ZMP is performed. Control can be performed. The acceleration sensor 96 and the attitude sensor 95 are configured as an acceleration sensor A1 and a gyro sensor G1, respectively, in FIG.

  Also, ground check sensors 191 and 192 and acceleration sensors 193 and 194 are disposed on the left and right legs 160R and 160L, respectively. The ground contact confirmation sensors 191 and 192 are configured by, for example, mounting a pressure sensor on the sole, and can detect whether or not the sole has landed based on the presence or absence of a floor reaction force. The acceleration sensors 193 and 194 are arranged at least in the X and Y axial directions. By disposing the acceleration sensors 193 and 194 on the left and right feet, the ZMP equation can be directly assembled with the feet closest to the ZMP position. In FIG. 3, sensors A2 and A2 for measuring acceleration at the foot and gyro sensors G2 and G3 for measuring the posture of the foot are arranged on the left and right ankles, respectively. In addition, force sensors F1 to F4 and F5 to F8 for measuring ground contact and floor reaction force are disposed at the four corners of the left and right soles.

  In the present embodiment, a reaction force sensor system (such as a floor reaction force sensor) that directly applies ZMP and force is disposed on a foot that is a contact portion with a road surface, and local coordinates used for control and the coordinates thereof are directly set. An acceleration sensor for measurement is provided. Therefore, more precise posture stabilization control can be realized at high speed by assembling the ZMP balance equation directly at the foot closest to the ZMP position.

  The main control unit 180 can dynamically correct the control target in response to the outputs of the sensors A1 to A3, G1 to G3, and F1 to F8. More specifically, adaptive control is performed on each of the sub-control units 135, 145, 155, and 165 to realize a whole body movement pattern in which the upper limbs, trunk, and lower limbs of the robot device 100 are driven in cooperation. To do.

The whole body movement of the robot apparatus 100 sets foot movement, ZMP trajectory, trunk movement, upper limb movement, waist height, and the like, and commands for instructing movement according to these setting contents to each sub-control section 135, 145, 155, and 165. Then, in each of the sub-control unit 135 and 145 ..., interprets the command received from the main control unit 181 outputs a drive control signal to each actuator _{M 1, M 2, M 3} ....

B. Passive wheel mechanism legged mobile robot has excellent ground adaptability, especially on rough terrain, it can exhibit movement ability that can not be realized with other movement mechanism forms, but on a flat moving surface, There is a problem with low energy efficiency with respect to speed. On the other hand, the robot apparatus according to the present embodiment can realize a hybrid type movement having both characteristics of a legged movement and a wheel type movement by detachably attaching a passive wheel mechanism to the foot. it can. Further, the wheel can passively obtain a propulsive force by the operation of the foot and does not include an actuator for driving the wheel, so that the total weight does not need to be increased.

  Specifically, a wheel mechanism composed of one or a plurality of wheels is mounted on the tip of the movable leg. It is assumed that all wheel mechanisms are composed of passively supported wheels, and the friction characteristics of each rotating shaft are adjusted. Based on the wheel configuration, the frictional characteristics of the foot around the X, Y, and yaw axes can be adjusted. In addition to adjusting the cross-sectional shape and physical properties of the wheel, and adjusting the attitude of the wheel to the main body, in addition to the friction characteristics, the geometric grounding state with respect to the grounding surface is adjusted, and the motion performance of the robot device such as propulsion performance and turning performance Can be improved.

In the conventional passive wheel mechanism for legged robots, as shown in FIG. 5, the propulsion principle using the frictional force in the X-axis direction of the wheel (the traveling direction in which the wheel itself rolls) and the Y-axis direction was discussed. . In this case, by utilizing the anisotropy of the drag force that the rolling direction of the wheel has a small friction coefficient and the friction in the axial direction is large, the movement in a direction non-parallel to the direction of travel of the foot is changed to the rotational movement of the wheel. It is possible to obtain the propulsive force in the propulsion direction of the robot apparatus by converting. The glide angle θ _G formed by the rolling direction of the wheel and the propulsion direction (or the main direction of movement of the robot) corresponds to the gear reduction ratio, and if a larger angle is set by the glide angle θ _{G, the} speed is reduced. A big driving force can be generated in the direction. Conversely, by giving a small angle to the glide angle θ _G , it is possible to propel the robot at a high speed although it has a small propulsive force.

  On the other hand, in the present embodiment, by considering the wheel configuration, the friction characteristic about the yaw axis is adjusted in addition to the X axis direction and the Y axis direction. Even if there is one wheel per leg, the friction characteristics can be adjusted as shown in FIG.

  In the case of four wheels per foot, the frictional force and torque are adjusted as shown in FIG. In this case, in the wheel mechanism composed of four wheels, the friction characteristics of the entire wheel mechanism are adjusted by using different characteristics for each wheel. Further, the center of rotation about the yaw axis may change depending on the friction characteristic distribution for each wheel.

  Further, when the wheel mechanism for each foot is composed of a plurality of wheel mechanisms, as shown in FIG. 8, in addition to the case where wheels are arranged for each corner of the sole, And changing the number of wheels on the line.

  Regarding wheels, by adjusting the wheel cross-sectional shape and physical properties, and adjusting the attitude of the wheel to the main body, in addition to the above-mentioned friction characteristics, the geometric grounding state with respect to the grounding surface is adjusted, and propulsion performance, turning performance, etc. Can improve athletic performance. For example, by devising the wheel shape as shown in FIG. 9, it is possible to change the ground contact portion and the ground contact state (shape, area and friction characteristics) at the sole. Examples of such wheel cross-sectional effects include the following.

(1) Prevention of catching on the ground (static friction, prevention of sudden changes in friction characteristics)
(2) Realization of swivel motion by inclining ground contact (3) Adjustment of ground contact area

  FIG. 10 shows an example in which a wheel mechanism composed of four wheels is configured using the wheels shown in FIG. As shown in the drawing, the ground contact portion of each wheel can be adjusted by the wheel cross-sectional shape. In this case, by bringing the grounding part of each wheel close to the outside of the foot, a large polygonal area connecting the grounding points is secured to ensure stability, and it is easy to ground at a specific part from matching with sensor characteristics. can do.

  Further, even if the wheel mechanism for each leg is configured with one wheel instead of multiple wheels as shown in FIG. 10, the deformation at the time of grounding is used in consideration of the material of the wheels as shown in FIG. Thus, the yaw axis friction torque can be generated.

  FIG. 7 illustrates a four-wheel wheel mechanism, but the ground contact state can be changed by changing the characteristics of each wheel. The following can be mentioned as an effect obtained by changing the characteristic of a wheel.

(1) Improved adaptability to road surface irregularities (2) Improved adaptability to road surface steps (3) Improved turning performance

  FIG. 12 shows a state in which the wheel mechanism adapts to the road surface level difference. As shown in the figure, in order to improve the sliding ability over the convex terrain such as steps, the front wheel of the wheel mechanism consisting of four wheels on the front, rear, left and right is made of soft (easy to deform) material, and interference when contacting the step The copying characteristics of the terrain can be improved.

  FIG. 13 shows an example in which the ease of deformation of the wheel and the ease of slipping of the surface are adjusted by paying attention to the turning characteristics. At the time of turning, if the toe (or heel) load is reduced, when sliding in the Y-axis direction (that is, performing skid steer), the wheel surface is preferably provided with a slippery characteristic. In this way, it is possible to adjust the ease of deformation of the wheels and the ease of slipping of the surface by paying attention to the steps and unevenness and the turning characteristics.

  All the wheel mechanisms according to the present embodiment are composed of passively supported wheels, and the friction characteristics of each rotating shaft are adjusted. That is, not a driving wheel but a passive wheel is attached in order to adjust a friction characteristic (to give directionality etc.). The principle of movement in such a wheel mechanism is to generate an advancing force by generating a trajectory of a leg (foot) or an inertial force of a robot apparatus body.

  It is considered that acceleration / deceleration can be further facilitated by appropriately adjusting the friction torque, including using a bearing that can support the wheel with minimal friction. In particular, in order to perform kicking acceleration from a standstill, it may be swung or unintentional movement may occur depending on conditions, so it is effective to adjust the shaft friction according to conditions such as the moving surface state. is there.

  FIG. 14 and FIG. 15 show the configuration of the wheel mechanism in the case of four wheels on the front and rear of the foot and on the left and right. In each figure, the bracket is a member for attaching to the foot portion of the legged mobile robot, and the shape can be arbitrarily designed by the leg structure. The following structure is symmetric with respect to the YZ plane.

  Front and rear foil stays are attached to the bracket. The wheels are pivotally supported at the left and right ends of the front and rear wheel stays so as to be rotatable about the axle. The front and rear wheel stays are arranged so that the left and right axles are substantially coaxial.

  Furthermore, an auxiliary sensor system for the wheel mechanism can be mounted. If sensors cannot be installed on all wheels due to installation space, cost, and other mounting restrictions, give priority to the inner foot (the arch side in human terms) and before grasping the kicked-out state Prioritize the edge side.

  Since it is necessary to adjust the characteristics of the wheel according to the state of the moving surface, the mechanism for attaching the wheel is preferably exchangeable.

  FIG. 16 shows a state in which a sensor is mounted on the wheel mechanism. If it is sufficient to know only the X-axis velocity of the foot coordinates at each foot, an angular velocity sensor may be installed on the inner foot front wheel as shown.

  Further, when a sensor for measuring the ground contact state is mounted on the sole, the installation state of the wheel is determined in consideration of the measurement method and the installation position. For example, when the foot mechanism has four measurement points (sensors for measuring the ground contact state of the sole) as shown in FIG. 3, the wheel measurement points may be matched as shown in FIG. This is effective in fully utilizing the resolution and measurement range.

  Further, like a human roller skate, a rubber block may be attached in order to assist in kicking out operation and deceleration operation. In this case, the following configuration is adopted.

(1) The wheel mechanism main body is not attached with a composition, and a certain degree of freedom is allowed.
(2) A support mechanism is provided for preventing the rubber from being caught even if the rubber has a relative speed with respect to the moving surface even if it is grounded.
(3) Rubber support should be linear or non-linear.

  FIG. 18 shows an example in which a rubber stopper is attached to the wheel mechanism. In the illustrated example, one end of a rubber stopper support portion having a spring element having a substantially U-shaped cross section is attached to the front end edge of the bracket that supports the wheels at the four corners of the front, rear, left, and right. A rubber stopper is supported. According to such a structure of the support portion, when the rubber stopper is grounded and spring elasticity is applied, the rubber stopper support portion is deformed with the bent portion of the dogleg as the center of rotation. Even if it is not sufficient, it can act so as not to be caught on the ground and to be dragged.

  FIG. 19 shows a state in which the wheel mechanism with the rubber stopper shown in FIG. 18 is tilted and the rubber stopper acts on the ground. In the illustrated example, the wheel diameter is 25 with respect to the total length 120 of the wheel mechanism. When the wheel mechanism main body is inclined by 5 to 30 ° with respect to the road surface, it acts on the rubber stopper or the road surface. At this time, the distance between the ground contact portion of the wheel and the ground contact portion of the rubber stopper is about 10-20.

  FIG. 20 shows how the rubber stopper acts when the toe touches down. In this case, the rubber stopper support portion is deformed in a direction to be flipped up by the relative speed of the toe relative to the ground, and the frictional force of the rubber stopper is reduced. That is, at the time of grounding, a relationship of trailing (drag direction) is established so that friction is not generated more than necessary.

  FIG. 21 shows a state in which the rubber stopper acts during the kicking-out operation. In this case, the frictional force increases because the rubber stopper support portion is deformed in the pull-in direction due to the relative speed of the toe relative to the ground. That is, when kicking out, it becomes a leading (hooking direction) position, and the geometrical arrangement increases the frictional force.

C. Sliding motion by a legged mobile robot using a passive wheel mechanism The legged mobile robot has excellent ground adaptability, especially on rough terrain, exhibiting a moving ability that cannot be realized by other moving mechanism forms. Can do. Furthermore, in the present embodiment, a passive type wheel mechanism (described above) is detachably attached to the foot, thereby realizing a hybrid type movement having both characteristics of a leg type movement and a wheel type movement.

  FIG. 22 schematically shows a functional configuration of the sliding motion control system 1 for performing a sliding motion by a legged mobile robot having a passive wheel mechanism at the foot. The illustrated system 1 includes a gait generator 10 that generates or edits a gait (or motion) of a legged mobile robot during a sliding motion, and a robot posture stabilization when the generated gait is reproduced on an actual machine. The posture stabilization processing unit 20 for obtaining the stability, and the gait after the posture stabilization processing, that is, the motion data is input to the actual machine to control the joint drive of the whole body including the leg part to perform the sliding motion. It is comprised by the exercise | movement control part 30 to be performed.

  The gait generator 10 can edit motion data using, for example, a motion editing apparatus described in Japanese Patent Laid-Open No. 2003-266347 already assigned to the present applicant. In this case, each joint angle data is directly input as posture data for forming a robot pose, or a pose change operation is performed on a 3D character, and each joint angle data is obtained from the pose by inverse kinematics calculation. can do. Then, the motion of the robot, that is, the gait is generated by interpolating between the poses arranged on the time axis.

  The posture stabilization processing unit 20 verifies the posture stability when reproducing the generated gait on an actual machine based on ZMP or other stability determination norms, and corrects the gait as appropriate when stability cannot be secured. The process which adds is performed. During this stabilization process, in order to form ZMP equations, equations of motion, or other stability discriminants, the movable range and output torque of each joint angle on the actual machine, the weight of each part, and other physical data The parameter consisting of etc. is used. For example, Japanese Laid-Open Patent Publication No. 2001-157793 already assigned to the present applicant discloses a walking control device for a robot that performs posture stability control based on a ZMP stability determination criterion. It can be applied to posture stability control during operation.

  In the present embodiment, the gait generator 10 generates or edits a sliding motion related to a legged mobile robot equipped with a passive wheel mechanism on the foot, such as the sliding speed, posture stability, and restrictions on joint movable angles. Various problems caused by the sliding motion can be solved, and a method for generating a gait that facilitates the stabilization process in the posture stabilization processing unit 20 can be provided.

C-1. Generation of basic sliding motion The walking motion by the two-legged mobile robot is performed by repeating the walking cycle divided into the following motion periods (described above).

(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

  When the ZMP stability criterion is used for posture stability control in walking motion, ZMP with zero pitch axis and roll axis moment is accommodated inside the support polygon formed by the ground contact point and the road surface. ZMP trajectory control is performed. When performing a sliding motion with a passive wheel mechanism on the foot, basically the ZMP trajectory is used when there is a one-leg sliding period or a sliding leg switching, as in the control algorithm for bipedal walking. By controlling, the contact between the roller and the floor surface is kept in a stable surface contact.

  On the other hand, there is an object of increasing the moving speed on a relatively flat road surface during sliding. For acceleration, the trajectory of the foot and the trajectory of the center of gravity are also important, but in this regard, skating and bipedal walking are different. In the present embodiment, by setting parameters and changing them, they are controlled in a unified manner corresponding to both. This also has the merit of reducing the amount of programs and shortening the development period.

  FIG. 23 illustrates a sliding motion based on a standard walking motion. In the case of illustration, the single leg support by the left and right legs is alternately repeated with the both leg support periods being separated. Here, when the support legs are exchanged during the both-leg support period, it is necessary to maintain consistency between the support legs and the landing legs in terms of the sliding speed and direction of the foot, and the positional relationship between the soles on the floor. If at least one of the sliding speed or the sliding direction is extremely different between the two legs, a fall is caused.

  It should be noted that the influence of acceleration caused by acceleration / deceleration during sliding is small as compared with gravitational acceleration, and can be ignored.

C-2. In the sliding operation shown in FIG. 23, single-leg support by the left and right legs is alternately repeated with the both-leg support period separated, and the support leg and the landing leg are exchanged when the support leg is exchanged in the both-leg support period. It is necessary to maintain consistency between the sliding speed and the sliding direction in the foot and the positional relationship between the soles on the floor. However, the processing for achieving this consistency has a high calculation load and causes an increase in cost.

  Therefore, by instantaneously replacing the support legs, it is not necessary to maintain consistency between the support legs and the landing legs regarding the sliding speed and direction of the foot, and the positional relationship between the soles on the floor. Can do. FIG. 24 illustrates a gliding motion with no or extremely short support period for both legs. In normal walking motion, the both-leg support period accounts for about 30% of the entire period. On the other hand, in the example shown in FIG. 24, the both-leg support period is at most 0.1%, which is as close to 0% as possible. In this case, it is not necessary to strictly consider the sliding speed, and the trajectory plan can be simplified.

C-3. At the time of kicking and sliding, a propulsive force or acceleration can be obtained by performing an action of kicking the floor surface when the rear leg leaves the floor.

  If the stroke of the kicking action becomes large, a large acceleration can be obtained, but a large joint movable range is required for each joint of the leg accordingly. In general, the joint movable range is often limited in the main joint drive unit including the leg portion, and a sufficiently large joint movable range cannot be taken.

  Therefore, in the present embodiment, by setting the trunk height to be higher than the standard posture, a large kicking stroke can be obtained with a relatively narrow joint movable range. This is because, when the movable angle of the ankle is small, a larger stroke can be obtained with a higher waist.

  FIG. 25 and FIG. 26 show a case of a normal kicking action and a state of performing the kicking action in a state where the trunk height is higher than the standard posture. As can be seen by comparing the two figures, there is almost no difference in the height of the trunk in the support period of both legs, but the gait is generated so that the height of the trunk does not sink much in the support leg retraction period. As can be seen from the figure, a large joint movable range is not necessary, and a large kicking operation is possible even when the joint movable range is limited.

C-4. Kicking operation including line grounding or point grounding When performing the acceleration operation to kick out as described above, the joint can be moved by using line grounding or point grounding when the rear leg leaves and kicks out during the support leg replacement period. Even when the range is limited, larger strokes can be obtained.

  FIG. 27 illustrates a state in which a kicking operation is performed using line grounding when the rear leg leaves the floor and kicks out. FIG. 28 shows a comparison between a kicking operation using line grounding and a kicking operation without line grounding. FIG. 28 left shows the largest kick width under the constraint that the movable range of the right ankle around the roll axis is 10 degrees. On the other hand, the right side of FIG. 28 shows the largest kick width when line grounding is used in the same movable range. As can be seen from the figure, by using line grounding or point grounding, a larger stroke can be obtained even when the joint movable range is limited.

C-5. It is effective to fully extend the knee of the free leg (kick leg) in order to increase the kicking stroke in the kicking skating including the state where the knee is extended . You will be able to land on areas that cannot be reached with your knees bent.

  FIG. 29 illustrates a state in which a kicking operation for completely extending the knee of the free leg (kick leg) is performed when the rear leg leaves and kicks out. Further, FIG. 30 shows a comparison between a kicking action in which the knee of the free leg (kick leg) is fully extended and a kick action in which the knee of the free leg (kick leg) is not fully extended under the same restriction of the movable range. Yes. As can be seen from FIG. 30, a larger stroke can be obtained even when the range of motion of the joint is limited by using the kicking action that fully extends the knee of the free leg (kick leg). .

C-6. For ordinary legged mobile robots that do not use sliding means such as a stop motion passive wheel mechanism for the sole of the foot, a stationary basic standing posture can be formed relatively easily by using ZMP and other stability criteria. Can do.

  On the other hand, a legged mobile robot to which a sliding means such as a passive wheel mechanism is applied cannot maintain a stopped state simply by executing a standing posture, and may slide in a standing posture.

  Therefore, in the present embodiment, the stop operation is performed by performing a posture control that prevents the robot from toppling over based on the ZMP or other stability determination norms and performing a braking operation that does not cause sliding in the passive wheel mechanism in parallel. Is to be realized.

  The braking operation for the passive wheel mechanism uses the property that the passive wheel mechanism does not work with a large frictional force in the direction of movement, that is, the rolling direction of the wheel, but a large frictional force acts in the direction perpendicular to the moving direction. This is executed by causing the moving directions of the passive wheel mechanism at the feet of the legs to intersect.

  Specifically, this braking operation is realized in a foot posture with the feet open as shown in FIG. If the left and right legs are not parallel when both feet are in contact with the ground, it is possible to decelerate and stop. In addition, when the vehicle has already stopped, the vehicle can continue to stop even when the floor surface is inclined or an external force is generated.

  FIG. 32 illustrates the principle of stopping with the feet open. As shown in the figure, when the foot tip is open, each foot can freely move in the traveling direction of the passive wheel mechanism, but frictional force acts when moving in a direction perpendicular thereto. If one foot tries to move in the direction of travel of the passive wheel mechanism, the other foot will also move in the direction in which the frictional force acts, and can be decelerated or stopped by this frictional force.

D. In the sliding operation using the support leg exchange described in the preceding section C using the both-leg ground contact , smooth sliding is performed during the period from the replacement of the support leg to the next replacement. This can be categorized into two, one is sliding on one foot and the other is sliding on both feet.

  FIG. 33 shows a state where the legged mobile robot slides with one leg. In this case, since the position of the wheel on the sole is fixed on the support leg side, the robot goes straight.

  FIG. 34 shows a state where the legged mobile robot slides with both feet. In this case, for example, if the left and right feet travel in parallel, they go straight, but in general, the left and right feet try to go straight in the direction of wheel movement, so it is necessary to plan a trajectory to meet this constraint. There is.

  On the other hand, by controlling the weight distribution for the four wheels constituting the passive wheel mechanism on the left and right soles, as shown in FIG.

  For example, as shown in FIG. 36, the right foot is put forward and its toes are floated in the air, the left foot is moved backward to lift the toes, and only the right foot that is put forward is rotated around the yaw axis. In such a case, the left and right foot portions are supported by only two wheels (four in total) at the rear (heel) and turn. This turning center is the intersection of the rotation axes of the rear wheels used on the left and right. Alternatively, the rotational axes of the left and right passive wheels that slide at the point where the turning center is corrected in consideration of the side slip due to the centrifugal force are made to intersect.

  In the example shown in FIG. 36, even if the roller at the toe portion is completely grounded without floating in the air, weight distribution is performed so that the vertical reaction force at the toe becomes smaller than the vertical reaction force at the toe. As a result, a side slip as shown in FIG. 37 occurs in the wheel of the toe portion, and the turning can be realized in the same manner.

  The reason why skidding occurs if weighted distribution is performed in this way will be described below. For the sake of explanation, FIG. 38 shows a legged mobile robot equipped with a passive wheel mechanism limited to a sagittal plane. The floor reaction force applied to the sole is defined as follows.

_f z_RFootToe: vertical ground reaction force acting on the right foot toes _f z_RFootHeel: vertical ground reaction force acting on the right foot heel _f z_LFootToe: vertical ground reaction force acting on the left foot toes _f z_LFootHeel: vertical floor reaction force applied to the left foot heel

  Assuming that the vertical floor reaction force of the toes is smaller than the vertical floor reaction force of the heel for both the left foot and the left foot, it is as follows.

f _{z_RFootToe} <f _{z_RFootHeel} and f _{z_LFootToe} <f _{z_LFootHeel}

On the other hand, the wheels when freely against the rotating direction of travel and does not act frictional force, the frictional force F _y in the lateral direction (direction perpendicular to the traveling direction) becomes as the following equation with respect to the right foot, lateral The toes with small static friction force slide sideways. Here, μ is a coefficient of static friction.

f _{z_RFootToe} <f _{z_RFootHeel}
⇔ μf _{z_RFootToe} <μf _{z_RFootHeel}
⇔ F _{y_RFootToe} <F _{y_RFootHeel}

  Similarly, the left foot is expressed by the following formula, and the toe side having a small lateral frictional force slides sideways.

f _{z_LFootToe} <f _{z_LFootHeel}
⇔ μf _{z_LFootToe} <μf _{z_LFootHeel}
⇔ F _{y_LFootToe} <F _{y_LFootHeel}

  The weight distribution is not limited to increasing the load on the heel roller as in the present example, and three or more rollers that do not want to cause skidding can be designated.

  The control of the turning motion by supporting both legs as described above can be performed by the following procedure.

Step 1) Decide which wheels will cause skidding and which wheels will not.
Step 2) The weight for the wheel causing the side slip is set small, and the weight for the wheel not causing the side slip is set large.

  When performing the control in step 2, if force control is performed, the weight may be directly controlled. When position control is performed, the weight may be controlled by controlling the center of gravity, ZMP control, or the pressure center point (or a plurality of pressure points) of each sole.

  However, as shown in FIG. 39, since the frictional force in the sliding state is smaller than the frictional force in the stationary state, if the wheel that has started to skid is stationary and the grounding point in the stationary state at the same time is in a skidding state, the load is applied. Allocation needs to change significantly. Further, as shown in FIG. 40, it is pointed out that the friction coefficient draws a curve depending on the sliding speed. Therefore, by considering this characteristic, it is possible to more accurately control the side slip.

  In addition, there is a possibility that the skid does not become as planned due to a change in the friction coefficient and a very small step. Therefore, it is possible to improve the robustness against these disturbances by feeding back the skid speed obtained from the sensor. The skid speed may be a slip ratio, or may be an estimated value instead of an actual value obtained from a sensor.

  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 embodiment 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, if it is a mechanical device or other general mobile device that performs a movement resembling human movement using electrical or magnetic action, it is a product belonging to another industrial field such as a toy. Even if it exists, this invention can be applied similarly.

  In the present specification, the embodiment in which the present invention is applied to a biped robot has been described. However, the present invention can also be applied to a multi-legged mobile robot such as a quadruped.

  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 should be taken into consideration.

FIG. 1 is a view showing a state in which a “humanoid” or “humanoid” robot apparatus 100 used for carrying out the present invention is viewed from the front. FIG. 2 is a view showing a state in which the “humanoid” or “humanoid” robot apparatus 100 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 robot apparatus 100. FIG. 4 is a diagram schematically showing a control system configuration of the robot apparatus 100. FIG. 5 is a diagram for explaining a propulsion principle using frictional forces in the X-axis direction of the wheel (the traveling direction in which the wheel itself rolls) and the Y-axis direction. FIG. 6 is a diagram for explaining a mechanism for adjusting the frictional force and torque in the case of one wheel per leg. FIG. 7 is a diagram for explaining a mechanism for adjusting the frictional force and torque in the case of four wheels per foot. FIG. 8 is a diagram illustrating an arrangement example of wheels of the wheel mechanism. FIG. 9 is a diagram illustrating a configuration example of a wheel shape. FIG. 10 is a diagram illustrating an example in which a wheel mechanism including four wheels is configured using the wheels illustrated in FIG. FIG. 11 is a diagram for explaining the operation of generating the yaw axis friction torque using the deformation at the time of ground contact when the wheel mechanism is constituted by one wheel. FIG. 12 is a diagram illustrating a state in which the wheel mechanism adapts to a step on the road surface. FIG. 13 is a diagram showing an example in which the ease of deformation of the wheel and the ease of slipping of the surface are adjusted by paying attention to the turning characteristics. FIG. 14 is a diagram showing a configuration of a wheel mechanism according to an embodiment of the present invention. FIG. 15 is a diagram showing a configuration of a wheel mechanism according to an embodiment of the present invention. FIG. 16 is a diagram illustrating a state in which a sensor is mounted on the wheel mechanism. FIG. 17 is a diagram illustrating a state in which the measurement points of the wheels are matched when there are four measurement points in the foot mechanism. FIG. 18 is a view showing an example in which a rubber stopper is attached to the wheel mechanism. FIG. 19 is a view showing a state where the wheel mechanism with the rubber stopper shown in FIG. 18 is tilted and the rubber stopper acts on the ground. FIG. 20 is a diagram illustrating a state in which the rubber stopper acts when the toe touches down. FIG. 21 is a diagram showing a state in which the rubber stopper acts during the kicking-out operation. FIG. 22 is a diagram schematically showing a functional configuration of the sliding motion control system 1 for performing a sliding motion by a legged mobile robot having a passive wheel mechanism at the foot. FIG. 23 is a diagram showing a sliding motion based on a standard walking motion. FIG. 24 is a diagram showing a sliding motion without a both-leg support period or extremely short. FIG. 25 is a diagram illustrating a normal kicking operation. FIG. 26 is a diagram illustrating a state in which the kicking motion is performed in a state where the height of the trunk is higher than the standard posture in comparison with the case of the normal kicking motion. FIG. 27 is a diagram illustrating a state in which a kicking operation is performed using line grounding when the rear leg leaves the floor and kicks out. FIG. 28 is a diagram showing a comparison between a kicking operation using line grounding and a kicking operation without line grounding. FIG. 29 is a diagram illustrating a state in which a kicking operation for completely extending the knee of the free leg (kick leg) is performed when the rear leg leaves the floor and kicks out. FIG. 30 is a diagram showing a comparison between a kicking action in which the knee of the free leg (kick leg) is fully extended and a kick action in which the knee of the free leg (kick leg) is not fully extended under the restriction of the same movable range. . FIG. 31 is a diagram showing a state in which a legged mobile robot to which a passive wheel mechanism is applied is stopped in a foot posture with its feet open. FIG. 32 is a diagram for explaining the principle of stopping with the foottip open. FIG. 33 is a diagram showing a legged mobile robot sliding on one leg. FIG. 34 is a diagram showing a legged mobile robot sliding on both legs. FIG. 35 is a diagram showing a legged mobile robot sliding with both feet. Fig. 36 shows a legged mobile robot with its right foot forward and its toes floating in the air, as well as moving the left foot back to lift the toes, and rotating only the right foot forward to rotate around the yaw axis. It is a figure for demonstrating the operation | movement which turns by this. FIG. 37 is a view for explaining an operation of causing a side slip to turn and turning. FIG. 38 is a diagram showing the floor reaction force applied to the left and right soles of a legged mobile robot equipped with a passive wheel mechanism limited to the sagittal plane. FIG. 39 is a diagram showing the relationship between the side slip speed of the wheel and the frictional force (however, it does not depend on the slip speed). FIG. 40 is a diagram showing the relationship between the side slip speed of the wheel and the frictional force (however, depending on the slip speed).

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Leg type mobile robot 101 ... Neck joint yaw axis 102A ... First neck joint pitch axis 102B ... Second neck joint (head) pitch axis 103 ... Neck joint roll axis 104 ... Shoulder joint pitch axis 105 ... Shoulder joint roll Axis 106 ... Upper arm yaw axis 107 ... Elbow joint pitch axis 108 ... Wrist joint yaw axis 109 ... Trunk pitch axis 110 ... Trunk roll axis 111 ... Hip joint yaw axis 112 ... Hip joint pitch axis 113 ... Hip joint roll axis 114 ... Knee joint pitch Axis 115 ... Ankle joint pitch axis 116 ... Ankle joint roll axis 130 ... Head unit 140 ... Trunk unit 141 ... Lumbar unit 150 ... Arm unit, 151 ... Upper arm unit 152 ... Elbow joint unit, 153 ... Forearm unit 160 ... Leg Unit 161, thigh unit 162, knee joint unit, 163, shin unit 1 DESCRIPTION OF SYMBOLS 80 ... Control unit, 181 ... Main control part 182 ... Peripheral circuit 191, 192 ... Grounding confirmation sensor 193, 194 ... Acceleration sensor 195 ... Attitude sensor 196 ... Acceleration sensor

Claims (26)

A legged mobile robot comprising a trunk and left and right movable legs connected to the trunk,
A passive wheel mechanism comprising a plurality of rotatably supported passive wheels attached to the sole of the movable leg;
An operation control means for controlling at least the operation of the movable leg,
The motion control means includes a sliding control for controlling a sliding speed and a sliding direction during sliding using the passive wheel mechanism while alternately switching a supporting leg between the left and right movable legs, and the legged movement during the sliding. Execute posture stability control that controls the posture stability of the robot based on a predetermined stability criterion,
This is a legged mobile robot. The motion control means performs posture stability control based on the ZMP stability determination standard so that 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. Execute,
The legged mobile robot according to claim 1. The passive wheel mechanism has each passive wheel attached so that surface contact is possible where two or more passive wheels contact the moving surface.
The legged mobile robot according to claim 1. The operation control means switches the support legs alternately between the left and right movable legs via both leg support periods.
The legged mobile robot according to claim 1. The movement control means lands the free leg so as to match the sliding speed and the sliding direction on the supporting leg side when shifting from the single-leg support to the both-leg support.
The legged mobile robot according to claim 4. The motion control means alternately switches the support legs between the left and right movable legs without going through both leg support periods or through an extremely short both leg support period,
The legged mobile robot according to claim 1. The passive wheel mechanism is capable of surface grounding in which two or more passive wheels are grounded on the moving surface and line grounding or point grounding in which only some of the passive wheels arranged in the sliding direction are grounded on the moving surface. Each passive wheel is attached,
The operation control means leaves the floor via the line grounding or point grounding when the support leg is switched to the free leg in the support leg replacement period.
The legged mobile robot according to claim 1. The movable leg includes a degree of freedom of joint around the knee pitch axis,
The motion control means is configured to extend the knee to the maximum when the support leg is switched to the free leg in the support leg replacement period.
The legged mobile robot according to claim 1. The motion control means simultaneously performs stop control of movement by the passive wheel mechanism and posture stability control based on a predetermined stability determination criterion when stopping or braking the sliding motion.
The legged mobile robot according to claim 1. The passive wheel mechanisms attached to the soles of the left and right movable legs are configured such that the frictional force in the rolling direction is smaller than that in the orthogonal direction,
The operation control means is configured so that the rolling direction of the passive wheel mechanism of the left and right movable legs is non-parallel during the stopping operation.
The legged mobile robot according to claim 9. The passive wheel mechanism supports the passive wheel rotatably at four locations on the front and rear and on the left and right so that the front and rear direction is the rolling direction,
The motion control means controls the posture of the foot on the left and right movable legs, and determines the passive wheels to be slid mainly by adjusting the distribution of vertical floor reaction forces applied to the four passive wheels.
The legged mobile robot according to claim 1. The motion control means includes a toe sliding that makes the vertical floor reaction force applied to the passive wheel on the toe side larger than the vertical floor reaction force applied to the passive wheel on the heel side, The vertical floor reaction force applied to the wheel is made larger than the vertical floor reaction force applied to the toe side passive wheel, and the heel sliding is performed by the passive wheel on the heel side.
The legged mobile robot according to claim 11. The motion control means causes the left and right movable legs to perform toe sliding or heel sliding when performing a turning operation, and causes the rotation axes of the left and right passive wheels to slide at a desired turning center. Or the rotation axes of the left and right passive wheels that slide at a point where the turning center is corrected in consideration of a side slip due to centrifugal force,
The legged mobile robot according to claim 11. A control method for a legged mobile robot having a trunk and a left and right movable leg connected to the trunk, the passive wheel comprising a plurality of passive wheels rotatably supported on the sole of the movable leg The mechanism is attached,
A sliding control step for controlling a sliding speed and a sliding direction using the passive wheel mechanism while alternately switching support legs between the left and right movable legs;
A posture stabilization control step for performing posture stability control for controlling posture stability of the legged mobile robot during sliding based on a predetermined stability criterion;
A control method for a legged mobile robot, comprising: In the posture stability control step, posture stability control is performed based on the ZMP stability determination standard so that 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. Run the
The method for controlling a legged mobile robot according to claim 14. The passive wheel mechanism has each passive wheel attached so that surface contact is possible where two or more passive wheels contact the moving surface.
The method for controlling a legged mobile robot according to claim 14. In the sliding control step, the support legs are alternately switched between the left and right movable legs via both leg support periods.
The method for controlling a legged mobile robot according to claim 14. In the sliding control step, when shifting from single-leg support to both-leg support, the free leg is landed so as to match the sliding speed and the sliding direction on the supporting leg side.
The method for controlling a legged mobile robot according to claim 17. In the sliding control step, the support legs are alternately switched between the left and right movable legs without passing through the both-leg support period or through the extremely short both-leg support period.
The method for controlling a legged mobile robot according to claim 14. The passive wheel mechanism is capable of surface grounding in which two or more passive wheels are grounded on the moving surface and line grounding or point grounding in which only some of the passive wheels arranged in the sliding direction are grounded on the moving surface. Each passive wheel is attached,
In the sliding control step, when the support leg is switched to the free leg in the support leg exchange period, the floor is left via the line grounding or the point grounding.
The method for controlling a legged mobile robot according to claim 14. The movable leg includes a degree of freedom of joint around the knee pitch axis,
In the sliding control step, when the support leg is switched to the free leg in the support leg exchange period, the knee is extended to the maximum extent;
The method for controlling a legged mobile robot according to claim 14. At the time of stopping or braking the sliding operation, simultaneously performing the movement stopping control by the passive wheel mechanism by the sliding control step and the posture stability control based on a predetermined stability determination criterion by the posture stability control step.
The method for controlling a legged mobile robot according to claim 14. The passive wheel mechanisms attached to the soles of the left and right movable legs are configured such that the frictional force in the rolling direction is smaller than that in the orthogonal direction,
In the sliding control step, the rolling direction of the passive wheel mechanism of the left and right movable legs is made non-parallel during the stopping operation.
The method for controlling a legged mobile robot according to claim 22. The passive wheel mechanism supports the passive wheel rotatably at four locations on the front and rear and on the left and right so that the front and rear direction is the rolling direction,
In the sliding control step, the posture of the foot is controlled in the left and right movable legs, and the passive wheels to be mainly slid are determined by adjusting the distribution of vertical floor reaction forces applied to the four passive wheels.
The method for controlling a legged mobile robot according to claim 14. In the sliding control step, the vertical floor reaction force applied to the passive wheel on the toe side is made larger than the vertical floor reaction force applied to the passive wheel on the heel side, and the toe sliding that slides on the passive wheel on the toe side, or passive on the heel side The vertical floor reaction force applied to the wheel is made larger than the vertical floor reaction force applied to the toe side passive wheel, and the heel sliding is performed by the passive wheel on the heel side.
The method for controlling a legged mobile robot according to claim 22. In the sliding control step, when the turning operation is performed, both the left and right movable legs are caused to perform tiptoe sliding or heel sliding, and the rotational axes of the left and right passive wheels that slide are crossed at a desired turning center. Or the rotation axes of the left and right passive wheels that slide at a point where the turning center is corrected in consideration of a side slip due to centrifugal force,
The method for controlling a legged mobile robot according to claim 25.

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