JP2003266358A - Robot device and revolute joint shaft driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain passive drive characteristic while ensuring high active drive characteristic of a revolute joint itself by taking physical interaction with a man into account. <P>SOLUTION: A revolute joint driving mechanism is constituted by connecting an actuator, a low decelerator, and a driving force transmission mechanism in this order to ensure the passive drive property of a revolute joint by the low decelerator. A link used as the driving force transmission mechanism is provided with nonlinear spring characteristic composed of a passive drive region in which it acts at comparatively low elastic constant during a period when driving force is comparatively low, an active drive region in which it acts at comparatively high elastic constant during a period when driving force is comparatively high, and a machine body protection region in which it acts at extremely low elastic constant when driving force exceeds a predetermined threshold. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot apparatus having a large number of joint degrees of freedom such as a legged robot and a joint axis drive apparatus, and more particularly to a joint apparatus having a plurality of degrees of freedom for each joint constituted by an actuator / motor. The present invention relates to a joint type robot device and a joint axis drive device.

More specifically, the present invention relates to a robot apparatus and a joint axis drive apparatus having two or more rotational degrees of freedom in one joint such as a hip joint, ankle, and shoulder joint. The present invention relates to a robot device and a joint shaft driving device in which at least a part of constituent actuators and motors are arranged apart from a joint shaft and a driving force is transmitted to the joint shaft by a transmission mechanism.

[0003]

2. Description of the Related Art A mechanical device that makes a motion similar to a human motion by using an electrical or magnetic action is called a "robot". The origin of the robot is the Slavic word "ROBO".
It is said that it is derived from "TA (slave machine)." In Japan, robots began to be popular since the end of the 1960s, but most of them are automation of production work in factories.
It was an industrial robot such as a manipulator and a transfer robot for the purpose of unmanned operation.

Recently, a model of the body mechanism and motion of a pet robot that imitates the body mechanism and motion of a quadruped animal such as a dog or cat, or an animal that walks upright on two legs such as a human. A robot called "humanoid" or "humanoid" designed by
Research and development on legged mobile robots such as manoid robots have progressed, and expectations for their practical application are increasing.

The legged mobile robot is generally provided with a large number of joint degrees of freedom, and the movement of the joint is realized by an actuator / motor. This is because such an actuator / motor is easy to handle, has a small size, high torque, and is excellent in responsiveness. Especially AC
Since the servo motor does not have a brush and is maintenance-free, it can be applied to joint actuators of legged robots that make their own action plans and walk freely. The AC servo motor has a permanent magnet on the rotor side and a coil on the stator side to generate a rotating torque on the rotor by the sinusoidal magnetic flux distribution and sinusoidal current. It has become. Then, by taking out the rotational position, the rotational amount, etc. of each joint motor with an encoder or a rotation sensor, and performing servo control, a desired operation pattern is reproduced, and
Attitude control is performed.

In a normal robot configuration, one joint degree of freedom is realized by one actuator / motor. on the other hand,
In order to construct a realistic robot that is similar to the motion mechanism of a quadruped animal such as a dog, a cat, or a bear, or a biped animal such as a human, a joint that is as close to a living body as possible is constructed. It is preferable to provide the degree of freedom.

For example, the biological model has two or more rotational degrees of freedom such as a roll axis and a pitch axis in main joint parts such as ankles, hip joints, and shoulder joints. 1 like this
In order to realize two or more degrees of freedom in one joint, it is necessary to combine two or more actuator motors. In such a case, the rotation axis of the actuator / motor and the rotation axis of the joint can be made to coincide with each other with respect to at least one joint degree of freedom, but the rotation axis of the actuator / motor can be changed with respect to other joint degrees of freedom. It must be placed away from the actual rotation axis of the joint. Of course, even in a joint having only one axis of freedom, because of the arrangement with other parts in the housing, that is, space efficiency,
The rotary shaft of the actuator / motor may be separated from the joint shaft. For this reason, a driving force transmission mechanism for transmitting the driving force of the motor to the rotary shaft of the joint is required.

For transmission of driving force in an automated machine such as a robot, it is common to use a timing belt, for example. In this case, in consideration of active driveability in the degree of freedom of joint, for example, an actuator, a belt, and a high speed reducer are connected in this order.

However, in the case of a robot of a type that emphasizes physical interaction with humans, such as an entertainment robot, the joint must have a high active driveability as well as a passive characteristic of the drive system itself. Is considered preferable.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an excellent articulated robot apparatus and articulated shaft drive apparatus in which the degree of freedom of each joint is formed by an actuator / motor.

A further object of the present invention is to provide an excellent robot device and joint axis drive device having two or more rotational degrees of freedom in one joint such as a hip joint, ankle or shoulder joint.

It is a further object of the present invention that at least a part of the actuator / motor that constitutes the degree of freedom of the joint is arranged apart from the joint shaft, and the driving force can be suitably transmitted to the joint shaft by the transmission mechanism. Another object is to provide a robot device and a joint axis drive device.

A further object of the present invention is to provide an excellent robot apparatus and joint axis driving apparatus which can give a joint a high passive driving performance in addition to a high active driving performance.

A further object of the present invention is to provide an excellent robot device and a joint axis driving device, which can obtain passive driving characteristics while securing the original high active driving characteristics in consideration of physical interaction with humans. To provide.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and is a robot apparatus having a plurality of joint degrees of freedom, in which at least some joints have joint axes. The driving force transmission unit includes a driving actuator and a driving force transmission unit that connects the joint shaft driving actuator and the joint shaft. The driving force transmission unit has a relatively low elastic constant during a period in which the driving force applied is relatively low. A robot apparatus characterized by having a non-linear spring characteristic including a passive drive range that operates at 1 and an active drive range that operates at a relatively high elastic constant during a period when the applied driving force is relatively high. is there.

The term "joint" as used herein refers to a portion having two or more rotational degrees of freedom, such as a combination of a roll axis and a pitch axis, such as an ankle, a hip joint, and a shoulder joint. In order to realize two or more degrees of freedom in one joint, it is necessary to combine two or more actuator motors. Therefore, with respect to at least one degree of freedom of the joint, the rotation axis of the joint actuator has to be arranged apart from the actual rotation axis of the joint. For this reason, a driving force transmission unit for transmitting the driving force of the actuator to the rotary shaft of the joint is required.

Conventionally, for example, an actuator, a belt, and a high speed reducer are connected in this order in consideration of active driveability in the degree of freedom of joints. In the case of a robot of a type that emphasizes physical interaction with humans, such as an entertainment robot, joints must have high active driveability and passive characteristics of the drive system itself.

Therefore, in the present invention, the use of the high speed reducer is stopped, and instead, the joint drive mechanism is constructed by connecting the actuator, the reduction speed reducer, and the driving force transmission mechanism in this order, and the joint is realized by the reduction speed reducer. The passive driveability of

When a belt is used as the driving force transmission mechanism, high tension must be applied to the belt in order to ensure high active driving performance. In such a case, it is necessary to manage the belt tension with high accuracy in order to secure active driveability, and it is necessary to secure the machine rigidity that can withstand high belt tension. It is accompanied by higher weight and larger size.

Therefore, in the present invention, the link mechanism is adopted as the driving force transmitting portion without using the belt. And I decided to give a nonlinear spring characteristic to this link.

The term "non-linear spring characteristic" as used herein means that the passive driving region operates with a relatively low elastic constant during a period when the applied driving force is relatively low and the period during which the applied driving force is relatively high. This means that the spring characteristics are switched according to the driving force, which is an active driving range that operates with a relatively high elastic constant.

The passive drive range is provided to absorb the backlash characteristics of the reduction gear reducer including a reduction gear. Therefore, the critical drive force for switching from the passive drive range to the active drive range can be determined according to the backlash characteristic of the reduction speed reducer. For example, if the reducer has no backlash, the passive drive range can be omitted.

The driving force transmission mechanism having the non-linear spring characteristic may further include a body protection zone that operates with an extremely low elastic constant when the applied driving force exceeds a predetermined threshold value. For example, if the robot body falls to the floor due to a fall, or if it collides with an obstacle, an extremely high external force is applied, and if the driving force transmission mechanism transmits the external force to the actuator as it is, the hardware will be destroyed. May be invited. Therefore, the driving force transmission mechanism operates in the machine body protection area to block high impact force from the actuator and the joint shaft, thereby preventing damage to the inside of the machine body and improving durability.

The driving force transmitting portion is, for example, a first connecting portion connected to the joint shaft driving actuator side,
Depending on a compressive force or a tensile force applied to the driving force transmission part, the insertion part is inserted between the second connection part connected to the joint shaft side and the first and second connection parts. It can be composed of an elastic portion that compresses or expands according to a predetermined elastic characteristic, and a maximum displacement amount setting portion that sets a maximum displacement amount due to compression or expansion of the elastic portion.

In such a case, the driving force transmitting section is displaced by the action of the elastic section with a relatively low elastic constant during the period when the applied driving force is relatively low, and the passive driving area is moved. Can be formed.

Further, the driving force transmitting portion includes a third connecting portion connected to the joint shaft driving actuator side, a fourth connecting portion connected to the joint shaft side, and the third and third connecting portions. And a second elastic portion that is inserted between the connecting portions of 4 and that compresses or expands with a predetermined elastic characteristic according to the compressive force or the tensile force applied to the driving force transmitting portion, and the compressive force or the tensile force. It can be configured with a displacement regulating portion that regulates the displacement of the second elastic portion until the force exceeds a predetermined value. In such a case, the driving force transmitting section secures an active driving range by restricting the displacement of the second elastic section by the action of the displacement restricting section until the applied driving force exceeds a predetermined threshold value. be able to. Then, when the applied driving force exceeds a predetermined threshold value, the restriction by the displacement restriction unit is released,
By the action of the second elastic portion, it can operate with an extremely low elastic constant to form a body protection zone.

For example, when the robot body falls to the floor surface due to a fall or the like, or when it collides with an obstacle,
Although an extremely high external force is applied, the displacement restriction section is released and operates in the machine body protection area, blocking high impact force from the actuator and joint shafts to prevent damage inside the machine body and durability. Can be improved.

Further, by disposing the driving force transmitting portion outside the machine body of the robot apparatus, the deformation amount or the momentum of the machine body is generated so that the ZMP position of the machine body is directed to substantially the center of the ZMP stable region. ZMP with high stability
A behavior space can be formed. In such a case, for example, it is possible to reduce the computer load for controlling the posture stability of the body during walking.

Further objects, features and advantages of the present invention are as follows.
It will be apparent from the embodiments of the present invention described later and the more detailed description based on the accompanying drawings.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 and FIG. 2 show a state in which a "humanoid" or "humanoid" legged mobile robot used in the practice of the present invention is upright, as viewed from the front and the rear respectively. ing. As shown in the figure, the legged mobile robot includes a body, a head, left and right upper limbs, and lower left and right lower limbs that perform legged movement. For example, a control unit built in the body ( (Not shown) controls the operation of the aircraft as a whole.

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

The control unit controls the drive of each joint actuator and each sensor (which will be described later) constituting the legged mobile robot.
It is a housing that mounts a controller (main control unit) that processes external input from devices such as a power supply circuit and other peripheral devices. The control unit may also include a communication interface and a communication device for remote operation.

The legged mobile robot configured as described above can realize bipedal locomotion by the whole-body coordinated motion control by the control unit. Such bipedal 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 with right leg lifted (2) Both legs support period with right foot grounded (3) Single leg support period with right leg lifted with right leg (4) Left leg supported Grounded both legs support period

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 two-leg support period, the correction of the lower limb trajectory is stopped, and the hip height is corrected to a constant value using the total correction amount for the planned trajectory. In the single-leg support period, a corrected trajectory is generated so that the corrected relative positional relationship between the ankle and the waist of the leg is returned to the planned trajectory.

In order to control the attitude of the airframe such as the trajectory correction of the walking motion, generally, interpolation using a quintic polynomial is performed so that the position, velocity and acceleration are continuous in order to reduce the deviation with respect to ZMP. It is calculated. ZMP
(Zero Moment Point) is used as a criterion for determining the walking stability. The stability discrimination criterion by ZMP is "Durhamber's principle" that gravity and inertial force from the walking system to the road surface, and these moments balance with the floor reaction force and floor reaction force moment as a reaction from the road surface to the walking system. based on. As a result of mechanical reasoning, the supporting polygon formed by the plantar ground contact point and the road surface (ie, ZMP stable region)
On the side of or inside the point where the pitch axis and roll axis moments are zero, that is, "ZMP (Zero Moment
Point) ”exists.

FIG. 3 schematically shows a joint degree of freedom configuration of the legged mobile robot. As shown in the figure, the legged mobile robot is an upper limb including two arms and a head 1, a lower limb composed of two legs for realizing a moving motion, and a body connecting the upper limb and the lower limb. It is a structure with a plurality of limbs composed of a trunk.

The neck joint (Neck) that supports the head has three degrees of freedom: a neck joint yaw axis 1, a neck joint pitch axis 2 and a neck joint roll axis 3.

Further, each arm has, as its degree of freedom, a shoulder joint pitch axis 4 at the shoulder (Shoulder), a shoulder joint roll axis 5, an upper arm yaw axis 6, and an elbow joint pitch axis 7 at the elbow (Elbow). , A wrist joint yaw axis 8 in the wrist (Wrist) and a hand portion. The hand is
In reality, it is a multi-joint, multi-degree-of-freedom structure including a plurality of fingers.

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

Each leg constituting the lower limb has a hip joint yaw axis 11 in a hip joint (Hip), a hip joint pitch axis 12, a hip joint roll axis 13, and a knee joint pitch axis 14 in a knee (Knee). Ankle joint pitch axis 15 and ankle joint roll axis 16 in the ankle
And a foot part.

However, the legged mobile robot for entertainment need not be equipped with all the above-mentioned degrees of freedom, or not limited to this. Depending on the design and manufacturing constraints and required specifications,
It goes without saying that the degree of freedom, that is, the number of joints can be appropriately increased or decreased.

Each degree of freedom of the legged mobile robot as described above is actually implemented by using an actuator. It is preferable that the actuator be small and lightweight in view of demands such as eliminating extra bulges in appearance and approximating the shape of a natural human body, and performing posture control for an unstable structure such as bipedal walking. . In this embodiment,
It was decided to mount a small AC servo actuator of the type directly connected to the gear and incorporating the servo control system into a single chip in the motor unit (for this type of AC servo actuator, for example, the applicant has already transferred it). Japanese Patent Laid-Open No. 2000-299970). In the present embodiment, by adopting the reduction speed gear as the direct connection gear, the passive characteristic of the drive system itself required for the robot of the type that emphasizes physical interaction with humans is obtained.

As can be seen from FIG. 3, in the joints of the legged mobile robot, there are several parts having a rotational degree of freedom of two or more axes at one place. For example, the neck of the airframe has joint degrees of freedom around the three axes of roll, pitch, and yaw. In addition, the shoulder has joint degrees of freedom around two axes of roll and pitch. Further, the trunk of the body has a degree of freedom of joint around two axes of roll and pitch. In addition, the hip joint that connects the body portion and the leg portion has joint degrees of freedom around two axes of pitch and yaw. Further, the knee has joint freedom about two axes of roll and pitch. Further, the ankle has joint degrees of freedom around two axes of roll and pitch.

In such a multi-degree-of-freedom joint, 2
The above actuators and motors must be combined. In such a case, the rotation axis of the actuator / motor and the rotation axis of the joint can be made to coincide with each other with respect to at least one joint degree of freedom, but the rotation axis of the actuator / motor can be changed with respect to other joint degrees of freedom. It must be placed away from the actual rotation axis of the joint. Of course, even in the case of a joint having only one axis of freedom, the rotary shaft of the actuator / motor may be separated from the joint shaft because of the arrangement with other parts in the housing, that is, space efficiency. For this reason, a driving force transmission mechanism for transmitting the driving force of the motor to the rotary shaft of the joint is required.

For transmission of driving force in an automated machine such as a robot, it is common to use a timing belt, for example. Conventionally, in consideration of active driveability in the degree of freedom of joint, for example, an actuator, a belt, and a high speed reducer are connected in this order.

However, in the case of a robot of a type that emphasizes physical interaction with humans, such as an entertainment robot, the joint must have a high active driveability as well as a passive characteristic of the drive system itself.

Therefore, first of all, the present inventors construct a joint drive mechanism by sequentially connecting an actuator, a reduction speed reducer, and a driving force transmission mechanism, and ensure the passive driveability of the joint by the reduction speed reducer. did.

In this case, high active driveability of the joint itself must be ensured. If a belt is used as the driving force transmission mechanism, high tension must be applied to the belt to ensure high active driving performance. In such a case, the following problems occur.

(1) It is necessary to manage the belt tension with high accuracy in order to secure the active driveability, which makes assembly and maintenance work difficult. (2) In addition to the rigidity required for walking, it is necessary to secure the rigidity of the machine body that can withstand a high belt tension, and as a result, the case becomes bulky, heavy and large. In addition, the housing is likely to change with time. (3) A belt width that can withstand high driving force and high belt tension is required, and space efficiency of the driving force transmission system of the machine body is reduced. (4) Change over time of the belt (elongation, breakage, bending fatigue, etc.)
Due to the low durability. (5) It has spring characteristics due to the expansion and contraction of the belt. (6) Belt slippage and backlash occur. (7) High torque cannot be transmitted.

Therefore, the present inventors decided to use a link instead of a belt as the driving force transmission mechanism and impart a non-linear spring characteristic to this link in order to secure the original active drive performance of the joint. .

The non-linear spring characteristic referred to here is a passive drive range that operates with a relatively low elastic constant during a period when the applied driving force is relatively low, and a period during which the applied driving force is relatively high. This means that the spring characteristics are switched according to the driving force, which is an active driving range that operates with a relatively high elastic constant.

The passive drive area is provided to absorb the backlash characteristics of the reduction gear reducer including a reduction gear. Therefore, the critical drive force for switching from the passive drive range to the active drive range can be determined according to the backlash characteristic of the reduction speed reducer. For example, if the reducer has no backlash, the passive drive range can be omitted.

The driving force transmission mechanism having the non-linear spring characteristic further has a body protection zone which operates with an extremely low elastic constant when the applied driving force exceeds a predetermined threshold value. For example, if the robot body falls to the floor due to a fall, or if it collides with an obstacle, an extremely high external force is applied, and if the driving force transmission mechanism transmits the external force to the actuator as it is, the hardware will be destroyed. May be invited. In this embodiment, in such a case, the driving force transmission mechanism operates in the machine body protection area, and thus does not transmit a high impact force to the actuator, so that damage to the inside of the machine body is prevented and durability is improved. You can

In the case of a robot modeled on a living body such as a human being, a dog, or a bear, the machine body is configured so as to be left-right uniform according to the biological mechanism. In such cases,
If unevenness occurs on the left and right sides of the machine due to processing errors and assembly errors, extra torque is generated in the drive system even in a static state, which may seriously affect the attitude stability control of the machine. For example, when a belt is used for transmitting the driving force, the tension of the belt is different between the left and the right, which makes the tension management complicated. On the other hand, according to the driving force transmission mechanism of the present embodiment, such non-uniformity can be naturally absorbed by the passive driving area.

Further, when the driving force transmission mechanism according to this embodiment is used, since the actuator is protected from the excessive load by the body protection region, the movable angle of the joint can be expanded.

Further, by disposing such a driving force transmission mechanism outside the body of the legged mobile robot, the deformation amount or the momentum of the body is adjusted so that the ZMP position of the body moves toward the approximate center of the ZMP stable region. It is possible to form a highly stable ZMP behavior space as generated. In such a case, for example, it is possible to reduce the computer load for controlling the posture stability of the body during walking.

4 to 6 show configuration examples of the non-linear spring characteristic of the driving force transmission mechanism according to this embodiment.

As shown in the respective drawings, the driving force transmission mechanism has a passive driving area which operates with a relatively low elastic constant during a period when the driving force applied is relatively low, and a driving force applied relatively. It has an active drive region that operates with a relatively high elastic constant during a high period, and an airframe protection region that operates with an extremely low elastic constant when the applied driving force exceeds a predetermined threshold value.

FIG. 4 shows an ideal non-linear spring characteristic of the driving force transmission mechanism in the case where the joint driving mechanism is configured by connecting the actuator, the speed reducer, and the driving force transmission mechanism in this order.

In this case, in the passive drive range, the drive force transmission mechanism operates substantially linearly with a low spring elastic constant to absorb the gear backlash of the reduction speed reducer. And
When the actuator is driven by the amount of backlash, it reaches the active driving range, the spring elastic constant becomes infinitely high, that is, it operates as a rigid body, and the decelerated drive of the actuator is transmitted to the joint shaft as it is. When the applied force reaches a predetermined limit value, the driving force transmission mechanism transits to the body protection zone, the spring elastic constant becomes almost zero, and the driving force is not transmitted at all. For example, even if an excessive external force is applied to the driving force transmission mechanism due to a fall of the vehicle body such as a fall or collision with an obstacle, the driving force transmission mechanism does not propagate the external force at all. Therefore, the joint shaft drive actuator connected to one end of the joint shaft and the joint shaft connected to the other end are shielded from the external force, so that damage can be avoided.

As shown in FIG. 4, in the passive drive range, the active drive range, and the airframe protection range, linear spring elastic constants are given to the driving force transmission mechanisms, respectively, to form nonlinear spring elasticity as a whole. Although it is ideal from a theoretical point of view, since the spring elastic constant changes discontinuously at the connection point between each region, it is possible that the attitude stability control system of the airframe adaptively follows the discontinuity in this mechanical system. It will be difficult. For example, a discontinuous change in the spring male constant may generate a vibration component of the control signal, which may adversely affect the stable operation of the control. Therefore, in the example shown in FIG. 5, in consideration of such stable operation of the attitude control system, the spring elastic constant of the driving force transmission mechanism is continuously and smoothly changed at the connection point between the regions. . It can be said that this is an ideal nonlinear spring characteristic of the driving force transmission mechanism in consideration of the stable operation of the control system.

However, since mechanical characteristics such as coil springs and leaf springs are used to obtain the spring characteristics, the characteristics shown in FIGS.
It is physically difficult to freely manufacture an ideal non-linear spring characteristic as shown in (1). Therefore, in practice,
The condition is as shown in FIG.

Next, with reference to the legs of the legged mobile robot shown in FIGS. 1 to 3, a specific mounting form of the driving force transmission mechanism according to the present invention will be described.

FIG. 7 illustrates the leg structure of the legged mobile robot. 8 and 9 show the legs viewed from the front and the side, respectively.

As described above, the leg has the hip joint yaw axis 11, hip joint pitch axis 12, hip joint roll axis 13, knee joint pitch axis 14 and ankle ankle joint pitch axis 15 in the hip joint. , The ankle joint roll shaft 16 and the foot portion.

In the example shown in FIG. 7, the hip joint roll shaft drive motor 121 is arranged so that its output shaft coincides with the hip joint roll shaft 13.

Further, the hip joint pitch axis drive motor 122
Cannot be arranged at a position where its output shaft coincides with the hip joint pitch axis 12 due to interference between the hip joint roll shaft driving motor 121 and the housings. In the illustrated example, while the rotary link 103 is attached to the hip joint pitch shaft 12,
The rotary link 104 is connected to the hip joint pitch axis driving motor 122.
It is attached to the output shaft 102 of.

The hip joint roll shaft drive motor 121 and the hip joint pitch shaft drive motor 122 are motor units of a direct gear type, and a built-in reduction speed gear (not shown) is attached to the output shaft. By using the low reduction gear, the passive characteristic of the drive system itself, which is required for the type of robot that emphasizes physical interaction with humans, is added.

The pair of rotary links 103 and 104 are connected by four-joint parallel link mechanisms 105 and 106, and the output shaft 102 of the hip joint pitch shaft 12 and the hip joint pitch shaft driving motor 122 is paired. With the rotation of the rotary links 103 and 104, the left and right links 105 and 106 are operated in the vertical direction. 10 to 12 are front views of the four-bar parallel link mechanism,
A side view and an apology are shown respectively.

By the action of such a four-bar parallel link mechanism, the output shaft 102 of the hip joint pitch axis drive motor 122 is
Is rotated by a fixed amount, the hip joint pitch shaft 12 is also rotated by an angle corresponding thereto. In the present embodiment, since the parallel link mechanism is used, the hip joint pitch shaft 12 and the output shaft 102 of the hip joint pitch shaft driving motor 122 rotate by the same angle.

The left and right links 105 and 106 are for ensuring a high active driveability of the joint itself and the passive characteristics of the drive system itself required for a robot of a type that emphasizes physical interaction with humans. Is given a non-linear spring characteristic. That is, each of the links 105 and 106 has a passive drive range that operates with a relatively low elastic constant during a period when the applied driving force is relatively low, and a relatively high range during a period when the applied driving force is relatively high. It has an active drive region that operates with an elastic constant and a body protection region that operates with an extremely low elastic constant when the applied drive force exceeds a predetermined threshold value, and the spring characteristic switches according to the drive force.

The passive drive range can absorb the backlash characteristic of the reduction speed reducer including a reduction gear. Further, by providing the active drive range, the driving force of the hip joint pitch drive shaft motor 122 can be increased.
Can be transmitted to the normal joint movement. Further, by providing the machine body protection area, for example, when the machine body of the robot falls to the floor due to a fall or collides with an obstacle, a high impact force is transmitted to the hip joint pitch axis motor 122 and the hip joint pitch axis 12. Since it does not occur, it is possible to prevent damage inside the machine body and improve durability.

There is a possibility that non-uniformity may occur between the left and right links 105 and 106 due to a processing error or an assembly error, and extra torque may be generated in the drive system even in a static state. Since the non-uniformity can be absorbed by the passive drive range of 105 and 106, it does not adversely affect the attitude stability control of the airframe.

Since the actuator is protected from an excessive load by the fuselage protection region of each link 105 and 106, the movable angle around the hip joint pitch axis 12 can be expanded to the limit of the mechanism.

Further, as shown in FIG. 7, the links 105 and 1
By arranging the four-joint link mechanism composed of 06 outside the robot body, high stability such that the deformation amount or the momentum of the body is generated so that the ZMP position of the body faces the approximate center of the ZMP stable region. A ZMP behavior space can be created. In such a case, for example, it is possible to reduce the computer load for controlling the posture stability of the body during walking.

Further, in the example shown in FIG. 7, the output shaft of the hip joint roll shaft driving motor 121 is directly connected to the hip joint roll shaft 12, and as a result of being eliminated by the housing of the motor 121, the hip joint pitch shaft driving motor is driven. The output shaft 102 of the motor 122 is arranged apart from the hip joint pitch shaft 12, and the two are connected by a four-bar linkage. Of course, in this modified example, the output shaft of the hip joint pitch shaft drive motor 122 is directly connected to the hip joint pitch shaft 11, while the output shaft of the hip joint roll shaft drive motor 121 is arranged apart from the hip joint roll shaft 13. The spaces may be connected by a four-bar link mechanism. However, in consideration of the attitude stability of the machine body, it is considered that the elimination of the cause of the rocking of the machine body in the left-right direction should be prioritized over the rocking of the machine body in the front-back direction. Therefore, as in the configuration example shown in FIG. 7, the output shaft of the hip joint roll shaft drive motor 121 is made to coincide with the hip joint roll shaft 13,
To make the rotation accuracy around the hip joint roll axis more strict,
It would be a more preferred embodiment.

If ratios and elements are set for each node of the four-bar linkage, the four-bar linkage will be a parallel link mechanism, a cross link mechanism, a double lever mechanism, a crank lever mechanism, a crank slider mechanism, etc. Can be mentioned. The four-bar linkage shown in FIG. 7 is only one embodiment of the present invention, and the same effects as the present invention can be obtained even if the linkage is replaced with another linkage.

Further, in the example shown in FIG. 7, the ankle joint roll shaft driving motor 125 is arranged so that its output shaft coincides with the ankle joint roll shaft 16.

On the other hand, the ankle joint pitch axis driving motor 124 is arranged apart from the ankle joint pitch axis 15. That is, the rotary link 11 attached to the output shaft 107 of the ankle joint pitch axis drive motor 124
0 and a rotary link 110 attached to the ankle joint pitch shaft 15 and a four-bar parallel link composed of a pair of left and right links 111 and 112, and the output shaft 10 of the ankle joint pitch shaft driving motor 124.
As 7 rotates in a fixed amount, the ankle joint pitch axis 15 also rotates by an angle corresponding thereto. The structure of the four-bar parallel link used here is substantially the same as that shown in FIGS.

The ankle joint roll axis drive motor 125 and the ankle joint pitch axis drive motor 124 use a reduction speed gear, so that the drive system required for a robot of a type that places importance on physical interaction with humans. It is given its own passive characteristics (same as above).

The left and right links 111 and 112 are for ensuring a high active driveability of the joint itself and the passive characteristics of the drive system itself required for a robot of a type that places importance on physical interaction with humans. Is given a non-linear spring characteristic. That is, each of the links 111 and 112 has a passive driving region that operates with a relatively low elastic constant during a period when the applied driving force is relatively low, and a relatively high range during a period when the applied driving force is relatively high. It has an active drive region that operates with an elastic constant and a body protection region that operates with an extremely low elastic constant when the applied drive force exceeds a predetermined threshold value, and the spring characteristic switches according to the drive force.

The passive drive range can absorb the backlash characteristic of the reduction speed reducer including a reduction gear and the like. Further, by providing the active drive range, the driving force of the ankle joint pitch axis drive motor 124 can be transmitted to the ankle joint pitch axis 15 to realize a normal joint operation. Further, by providing the body protection area, for example, when the body of the robot falls to the floor due to a fall or collides with an obstacle, the ankle joint pitch axis motor 124
Since no high impact force is transmitted to the ankle joint pitch axis 15 or the ankle joint pitch axis 15, damage to the inside of the body can be prevented and durability can be improved.

There is a possibility that, due to a processing error or an assembly error, non-uniformity occurs between the left and right links 111 and 112, and extra torque is generated in the drive system even in a static state. Since the non-uniformity can be absorbed by the passive drive range of 111 and 112, the posture stability control of the airframe is not adversely affected.

Since the actuator is protected from an excessive load by the fuselage protection region of each link 111 and 112, the movable angle around the ankle joint pitch axis 15 can be expanded to the limit of the mechanism.

Further, as shown in FIG. 7, the links 111 and 1
By arranging the four-joint link mechanism consisting of 12 on the outside of the robot body, high stability such that the deformation amount or the momentum of the body is generated so that the ZMP position of the body faces the approximate center of the ZMP stable region. A ZMP behavior space can be created. In such a case, for example, it is possible to reduce the computer load for controlling the posture stability of the body during walking.

Further, in the example shown in FIG. 7, the output shaft of the ankle joint roll shaft driving motor 125 is the ankle joint roll shaft 16
Directly connected to the ankle joint pitch axis drive motor 12
The output shaft 107 of No. 4 is arranged so as to be separated from the ankle joint pitch shaft 15 and is connected to each other by a four-bar link mechanism, but conversely, the output shaft of the ankle joint pitch shaft driving motor 124. May be directly connected to the ankle joint pitch shaft 15, while the output shaft of the ankle joint roll shaft driving motor 125 may be arranged apart from the ankle joint roll shaft 16 so as to connect them by a four-bar linkage mechanism. .
However, in consideration of the attitude stability of the machine body, it is considered that the elimination of the cause of the rocking of the machine body in the left-right direction should be prioritized over the rocking of the machine body in the front-back direction. Therefore, as in the configuration example shown in FIG. 7, the output shaft of the ankle joint roll shaft driving motor 125 is matched with the ankle joint roll shaft 16,
It would be a more preferable embodiment to make the rotation accuracy around the ankle joint roll axis more precise.

As described above, in the four-bar parallel link, the left and right links 105 and 106 for transmitting the driving force obtained from the output shaft of the motor to the rotary shaft side, and the links 111 and 112 are connected to the joint itself. Non-linear spring characteristics are provided in order to secure both the high active driveability and the passive characteristics of the drive system itself required for the type of robot that emphasizes physical interaction with humans.

That is, each of the links 105 ... Compares the passive drive region which operates with a relatively low elastic constant during the period when the applied driving force is relatively low with the passive drive region during the period when the applied driving force is relatively high. It has an active drive region that operates with a relatively high elastic constant and a body protection region that operates with an extremely low elastic constant when the applied drive force exceeds a predetermined threshold, and the spring characteristics are switched according to the drive force.

Hereinafter, a specific example of the structure of the link having such a non-linear spring characteristic will be described.

FIG. 13 shows a structural example for realizing the passive drive characteristic of the nonlinear spring characteristics of the link.

In the example shown in the figure, the link is the first connecting portion 501 connected to the joint shaft driving actuator side.
And a second connecting portion 502 connected to the joint shaft side and a predetermined elastic characteristic according to the compressive force applied to the link, which is inserted between the first and second connecting portions. It is composed of an elastic portion 503 that compresses.

First connecting portion 501 and second connecting portion 50
Reference numeral 2 designates connecting portions 501A and 502A for connecting to other members such as a rotary link at both ends of the link.

At one end of the first connecting portion 501, the protrusion 50
5 is formed. On the other hand, a hole portion 504 for inserting the projection 505 on the first connecting portion 501 side is formed at one end of the second connecting portion 502. As shown in FIG. 13, the protrusion 505 is projected and retracted on the inner wall of the hole 504 while being guided, and as a result, the entire link is expandable and contractable in the longitudinal direction thereof.

An elastic portion 503 made of, for example, a Σ-shaped leaf spring is buried in the hole portion 504 so that the Σ mouth faces upward. Also, on the bottom side of the leaf spring, a protrusion 505
A receiving portion 506 is provided that abuts on the tip of the.

When a compressive force is applied in the longitudinal direction of the illustrated link by the operation of the joint shaft drive motor, the first
The projection 505 on the connecting portion side of the hole 50 on the second connecting portion side
In 4 inside, while resisting the restoring force of the Σ-shaped leaf spring 503,
It is gradually buried according to the compression force of the drive motor. This provides a passive drive action for the link.

Then, when the compressive force on the link increases and the displacement amount of the leaf spring 503 reaches a predetermined value, the protrusion 50
As a result of the tip of No. 5 contacting the receiving portion 506 and receiving the maximum repulsive force, the burial of the protrusion 505, that is, the contraction of the link is stopped. After that, the elastic constant of the link as a whole is remarkably increased, and the link is switched to the active drive range.

Further, FIG. 14 shows an example of the structure for realizing the body protection area of the nonlinear spring characteristics of the link.

In the example shown in the figure, the link is the third connection portion 601 connected to the joint shaft driving actuator side.
A second connecting portion 602 connected to the joint shaft side, a hollow guide portion 603 for guiding one end of each of the connecting portions 601 and 602 in the longitudinal direction of the link, and the guide portion 603.
The elastic portion 604 is housed inside and compresses with a predetermined elastic characteristic in accordance with the compressive force applied to the link.

Third connecting portion 601 and fourth connecting portion 60
Reference numeral 2 designates connecting portions 601A and 602A for connecting to other members such as a rotary link at both ends of the link.

Small projections 601B and 602B are provided at one end of each of the connecting portions 601 and 602, respectively.
In addition, a guide groove 603A having a linear shape for inserting these small protrusions 601B and 602B is formed in the side surface of the guide portion 603 in the longitudinal direction of the link, and the direction of expansion and contraction between the connection portions 601 and 602 is formed. Is regulated in the longitudinal direction.

One end faces of the connecting portions 601 and 602 are formed in a tapered shape. The elastic portion 604 is composed of, for example, a torsion spring, and both ends of the elastic portion 604 are connected to the connecting portions 60.
It is in contact with the end faces of 1 and 602.

The torsion spring 603 is substantially linear in the initial state, and in this state, it is possible to oppose the compressive force applied to the link as the compressive stress of the bar. That is, in this state, the elastic constant of the elastic portion 603 is extremely high, which can provide the active driving action of the link.

When the compression on the link further increases and reaches a predetermined value, the torsion spring 603 starts buckling. In this case, the torsion spring 603 has a substantially V-shape as shown in the drawing, and both ends of the torsion spring 603 have connecting portions 601.
And 602 slide down the taper of each one end surface, and buckling further progresses. In such a state, torsion
The spring 603 opposes the compressive force applied to the link as bending stress of the bar. Bending stress is extremely low compared to compressive stress. Therefore, the elastic constant of the link as a whole decreases significantly when the compressive force increases and reaches a predetermined value. As a result, the body protection area of the link can be obtained.

For example, by connecting and using the links shown in FIGS. 13 and 14 in series, it is possible to realize a link having a passive drive area, an active drive area, and a body protection area.

[Supplement] The present invention has been described in detail with reference to the specific embodiments. However, it is obvious that those skilled in the art can modify or substitute the embodiments without departing from the scope of the present invention.

The subject matter of the present invention is not necessarily limited to products called “robots”. That is, as long as it is a mechanical device that performs a motion similar to a human motion by using an electric or magnetic action, even if it is a product belonging to another industrial field such as a toy, the present invention is similarly applied. Can be applied.

In short, the present invention has been disclosed in the form of exemplification, and the contents described in this specification should not be construed in a limited manner. To determine the gist of the present invention,
The claims section mentioned at the beginning should be taken into consideration.

[0110]

As described above in detail, according to the present invention,
Provided is an excellent robot device and a joint shaft driving device in which at least a part of an actuator / motor constituting a joint degree of freedom is arranged apart from a joint shaft and a driving force can be suitably transmitted to the joint shaft by a transmission mechanism. can do.

Further, according to the present invention, it is possible to provide an excellent robot apparatus and joint axis driving apparatus capable of imparting higher passive driving performance to joints in addition to high active driving characteristics.

Further, according to the present invention, in consideration of physical interaction with a human, an excellent robot apparatus and joint axis drive capable of obtaining passive drive characteristics while securing high active drive characteristics of the original joint. A device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which a legged mobile robot used for implementing the present invention is upright as viewed from the front.

FIG. 2 is a view showing a state in which a legged mobile robot used for implementing the present invention is upright, as viewed from the rear.

FIG. 3 is a diagram schematically showing a joint degree of freedom configuration of a legged mobile robot.

FIG. 4 is a diagram showing a configuration example of a nonlinear spring characteristic of the driving force transmission mechanism according to the present embodiment.

FIG. 5 is a diagram showing a configuration example of a non-linear spring characteristic of the driving force transmission mechanism according to the present embodiment.

FIG. 6 is a diagram showing a configuration example of a nonlinear spring characteristic of the driving force transmission mechanism according to the present embodiment.

FIG. 7 is a diagram showing a leg structure of a legged mobile robot.

FIG. 8 is a diagram showing a leg structure of a legged mobile robot.

FIG. 9 is a diagram showing a leg structure of a legged mobile robot.

FIG. 10 is a front view of a four-bar parallel link mechanism used for transmitting driving force to a joint shaft.

FIG. 11 is a side view of a four-bar parallel link mechanism used for transmitting driving force to a joint shaft.

FIG. 12 is a perspective view of a four-bar parallel link mechanism used for transmitting driving force to a joint shaft.

FIG. 13 is a diagram showing a configuration example for realizing a passive drive characteristic of the nonlinear spring characteristics of the link.

FIG. 14 is a diagram showing a configuration example for realizing a passive drive characteristic of the nonlinear spring characteristics of the link.

[Explanation of symbols]

1 ... Neck joint yaw axis 2 ... Neck joint 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 ... Body Stem pitch axis 10 ... Trunk roll axis 11 ... Hip joint yaw axis 12 ... Hip joint pitch axis 13 ... Knee joint roll axis 14 ... Knee joint pitch axis 15 ... Ankle joint pitch axis 16 ... Ankle joint roll axis 102 ... Hip joint pitch axis drive Motor output shafts 103, 104 ... Rotating links 105, 106 ... Link 107 having nonlinear spring characteristics ... Output shafts 109, 110 of ankle joint pitch axis driving motors ... Rotating links 111, 112 ... Having nonlinear spring characteristics Link 121 ... Hip joint roll axis drive motor 122 ... Hip joint pitch axis drive motor 124 ... Ankle joint pitch axis drive motor 125 ... Ankle joint roll axis drive motor 5 DESCRIPTION OF SYMBOLS 1 ... 1st connection part, 501A ... Connection part 502 ... 2nd connection part, 502A ... Connection part 503 ... Elastic part (leaf spring) 504 ... Hole part 505 ... Protrusion 506 ... Receiving part 601 ... Third connection part , 601A ... Connection part, 601B ...
Small protrusions 602 ... Fourth connecting portion, 602A ... Connecting portion, 602B ...
Small protrusion 603 ... Guide portion, 603A ... Guide groove 604 ... Elastic portion (torsion spring)

Continued front page    (72) Inventor Jinichi Yamaguchi             5-14-38 Tamadaira, Hino City, Tokyo F term (reference) 2C150 BA08 CA01 DA04 DA24 DA26                       DA27 DA28 EB01 EC03 EC15                       EC19 EC25 EC26 EC28 ED11                       ED42 ED52 EF07 EF09 EF16                       EF17 EF22 EF23 EF33 EF36                       EH07 EH08                 3C007 CS08 CY00 CY32 HS27 HT11                       HT36 WA03 WA13

Claims (14)

[Claims] 1. A robot apparatus having a plurality of joint degrees of freedom, wherein at least a part of the joints has a joint axis drive actuator, and a drive force transmission section connecting the joint axis drive actuator and the joint axis. The driving force transmitting section compares a passive driving region that operates with a relatively low elastic constant during a period when the applied driving force is relatively low with a passive driving region during a period when the applied driving force is relatively high. A robot apparatus having a non-linear spring characteristic having an active drive range that operates with a relatively high elastic constant. 2. The driving force transmitting portion is connected to the joint shaft driving actuator via a speed reducer, and the critical driving force for switching from the passive drive range to the active drive range has a backlash that the speed reducer has. The robot apparatus according to claim 1, wherein the robot apparatus is determined according to characteristics. 3. The driving force transmitting portion further comprises a body protection zone which operates with an extremely low elastic constant when the applied driving force exceeds a predetermined threshold value. Robotic device. 4. The robot apparatus according to claim 1, wherein the driving force transmission unit is arranged outside a machine body of the robot apparatus. 5. The driving force transmitting portion includes a first connecting portion connected to the joint shaft driving actuator side, a second connecting portion connected to the joint shaft side, and the first and the second connecting portions. An elastic part that is inserted between the two connecting parts and that compresses or expands according to a predetermined elastic characteristic in accordance with a compressive force or a tensile force applied to the driving force transmitting part; and compressing or expanding the elastic part. 2. The robot apparatus according to claim 1, further comprising: a maximum displacement amount setting unit configured to set the maximum displacement amount according to. 6. The driving force transmitting portion includes a third connecting portion connected to the joint shaft driving actuator side, a fourth connecting portion connected to the joint shaft side, and the third and the third connecting portions. A second elastic portion that is inserted between the connecting portions of 4 and that compresses or expands with a predetermined elastic characteristic according to the compressive force or the tensile force applied to the driving force transmitting portion; The robot apparatus according to claim 1, further comprising: a displacement restricting portion that restricts displacement of the second elastic portion until a force exceeds a predetermined value. 7. A robot apparatus having a plurality of joint degrees of freedom, wherein at least a part of the joints comprises a joint axis drive actuator for applying a driving force to a joint axis, and the joint axis drive actuator. A robot apparatus, comprising: a reduction speed reducer that decelerates at a low reduction ratio; and a driving force transmission unit that connects the reduction speed reducer and a joint shaft. 8. A joint shaft drive device for a mechanical device having one or more joint degrees of freedom, wherein a joint shaft drive actuator and a drive force transmission connecting the joint shaft drive actuator and the joint shaft. The driving force transmitting portion is a passive driving region that operates with a relatively low elastic constant during a period when the applied driving force is relatively low, and a period during which the applied driving force is relatively high. Joint drive device having a non-linear spring characteristic with an active drive range that operates with a relatively high elastic constant in 9. The driving force transmitting portion is connected to the joint shaft driving actuator via a speed reducer, and the critical driving force for switching from the passive drive range to the active drive range has a backlash that the speed reducer has. The joint shaft drive device according to claim 8, wherein the joint shaft drive device is determined according to characteristics. 10. The drive force transmission portion further has a body protection zone that operates with an extremely low elastic constant when the applied drive force exceeds a predetermined threshold value. Joint shaft drive 11. The joint shaft driving device according to claim 8, wherein the driving force transmitting portion is arranged outside a machine body of the mechanical device. 12. The driving force transmitting portion includes a first connecting portion connected to the joint shaft driving actuator side, a second connecting portion connected to the joint shaft side, and the first and the second connecting portions. An elastic part that is inserted between the two connecting parts and that compresses or expands according to a predetermined elastic characteristic in accordance with a compressive force or a tensile force applied to the driving force transmitting part; and compressing or expanding the elastic part. The maximum displacement amount setting unit that sets the maximum displacement amount according to the above item, and the joint shaft drive device according to claim 8. 13. The driving force transmitting portion includes a third connecting portion connected to the joint shaft driving actuator side, a fourth connecting portion connected to the joint shaft side, and the third and the third connecting portions. A second elastic portion that is inserted between the connecting portions of 4 and that compresses or expands with a predetermined elastic characteristic according to the compressive force or the tensile force applied to the driving force transmitting portion; 9. The joint shaft drive device according to claim 8, further comprising: a displacement restricting portion that restricts displacement of the second elastic portion until a force exceeds a predetermined value. 14. A joint shaft drive device for a mechanical device having one or more joint degrees of freedom, the joint shaft drive actuator applying a driving force to the joint shaft, and the drive of the joint shaft drive actuator. And a driving force transmitting unit that connects the reduction speed reducer and the joint shaft.