JP2819323B2 - Joint control device for legged walking robot - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a joint control device for a legged walking robot, and more specifically, to a compliance control at the time of landing in a bipedal mobile robot to drive its joint. Control and
The present invention relates to a joint control device for a legged walking robot that adapts well to unevenness of a road surface and absorbs impact at the time of landing.

(Problems to be Solved by Conventional Techniques and Inventions) To overcome a wider moving environment, there is a legged moving machine. Among them, there is a possibility that the robot can freely operate even in a narrow working environment. A walking mechanism of a walking type (hereinafter, referred to as a “biped robot”) is conceivable.

Considering posture control of a mobile robot having a plurality of legs including such a bipedal walking robot, the bipedal walking robot is more unstable than the quadrupedal robot. It is desirable that the sole of the foot be imitated on the road surface by appropriately controlling the driving motor of the ankle joint and the driving motor for driving the foot joint in order to realize stable walking with less impact. To alleviate the impact, it is also possible to physically provide an impact cushioning material on the sole of the foot in addition to using control technology, but when targeting all road surfaces, the foot collides with the road surface unless the buffer operation is performed by control In such a state, the foot is rebounded by the reaction, and it is difficult to secure the stability. In particular, since a bipedal walking robot has a high center of gravity and a small contact area at the sole, it is extremely important to ensure stability during landing.

From that point, in Japanese Patent Application Laid-Open No. 62-97005, 2
A joint control method for a walking robot has been proposed. However, this prior art focuses on switching the control mode according to the work environment, that is, discriminating the swing phase and the stance phase from the presence or absence of the touchdown, and switching from the position feedback to the force feedback. It did not touch on the details of force feedback control. As an example to disclose the scanning control more specifically, see the paper, "Force Feedback Control of Robot Arm" (Measurement and Control, Vol.25, No.1, January 1986)
Can be mentioned. In this conventional technique, a virtual compliance mechanism is set for a robot hand having six free seats, an external force (force / moment) acting on the robot hand is detected, and the operating speed of the hand is set accordingly, and a servo is set. We propose a virtual compliance control that can achieve the same effect as a robot following by an actual compliance mechanism by controlling the speed of the motor so that the hand actually takes that speed. I have.

An object of the present invention is to apply the concept of the virtual compliance control described above to the landing control of a legged walking robot. An object of the present invention is to provide a joint control device of a legged walking robot that enables a small and flexible landing. However, in the above-mentioned conventional technology, a robot arm is targeted. In the case of a robot arm, since the arm body is attached to an infinitely heavy base, the load of the joint actuator that performs compliance control is applied only to the hand, and the hand is unlikely to oscillate when acting on an object. In the case of, the compliance control is performed for the movement of the upper body, but since the foot is not fixed to the road surface, the load of the ankle joint actuator may be applied to the lightweight sole, and oscillation is extremely high. Easy to happen.

Accordingly, a second object of the present invention is to provide a joint control device for a legged walking robot that enables a flexible landing operation without causing oscillation in the virtual compliance control.

Furthermore, since the landing operation is completed in a very short time, it is necessary to optimally set the characteristics of the servomotor in accordance with the walking conditions in order to complete the following operation during this time.

Accordingly, a third object of the present invention is to provide a joint control device for a legged walking robot having various control characteristics to be appropriately selected according to walking conditions.

(Means for Solving the Problems) For example, as set forth in claim 1, a servo mechanism for controlling a joint of a robot to follow a target position is provided, and the operation amount is changed according to an external force acting on the robot to copy the robot. In the joint control device to be operated, the joint is a joint including a foot joint of a legged walking robot having a sole at a tip, and the control device detects an external force acting on the sole and reduces the external force. In this configuration, the sole of the foot is adjusted while landing on the road surface.

(Operation) As shown in the control block diagram of FIG. 1, the external force acting on the sole at the time of landing is detected and reduced so that the road surface reaction force can be effectively absorbed. Since the road surface has irregularities, it can be landed flexibly and a stable landing with less impact can be constituted.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. Referring to FIG. 2, the whole walking robot according to the present invention will be schematically described. As apparent from the drawing, this walking robot 1 has a form close to that of a human. The lower leg 12, the thigh 14, and the torso 16 are connected to each other by an ankle 18, a knee 20, and a hip 22, respectively. Each joint has a DC electric motor 24,2
6,28,30,32,34 are arranged. This walking robot 1
Is symmetrical with respect to each member including the foot, so only one of them will be described in the following description.

FIG. 3 is a cross-sectional view (sagittal plane, in this case, cut in a plane parallel to the straight running direction) of the foot 10, and FIG. 4 is a partially cutaway front view thereof. In FIG. 4, at the ankle 18, a first electric motor 24 having a belt 36 attached to the lower leg 12 (for convenience of illustration, it is shown at the ankle position in FIG. 2; (Attached to the convenient position of the thigh 12) and input to the input terminal of the harmonic reducer 38 (product name).
In the speed reducer, the motor output is reduced and increased at an appropriate magnification, as is well known, and the fixed portion 40 attached to the lower leg portion 12 and the rotating portion 42 below the fixed portion 40 are moved in the walking direction around the axis 44. Relative rotation. A third position perpendicular to the axis 44
As shown in the figure, the second electric motor 26 is disposed, and its output is input to a second harmonic reducer 46, and the fixed unit 40 and the rotating unit 42 are connected around a second axis 48. Relative rotation in the left-right direction (roll direction) perpendicular to the traveling direction (pitch direction).

A known six-axis force sensor 50 is attached below the rotating part 42, and three-directional components Fx, Fy, and Fz of force and three-directional components of moment are provided.
Mx, My, and Mz are measured separately, and the presence or absence of landing on the foot or the contact load is detected. A hull-shaped frame 52 is fixed below the six-axis force sensor 50. The frame 52 is made of a lightweight and highly rigid material such as an aluminum material, and its lower surface forms a sole portion (so-called sole) 54. The toe 58 and the heel 60 at the sole 54 are curved at an appropriate curvature to facilitate rolling when touching down, to absorb the impact of landing, and to adapt to the uneven road surface. Elastic bodies 64 and 66 made of a rubber material or the like having a uniform thickness are attached by appropriate means such as adhesion. Note that the other joints including the knee joint 20 have substantially the same structure, and a description thereof will be omitted.

Next, the control unit will be described.
An energy source 16 is housed and supplied to the electric motor 24 and the like, and a control unit 70 having a microcomputer is housed therein to control the walking operation. That is, the output of the six-axis force sensor 50 is sent to the control unit 70 via a signal line 72, and each of the electric motors has a rotary encoder 74, 76 for detecting its rotation angle (FIG. Are shown, and the detected values are sent to the control unit 70. FIG. 5 is an explanatory block diagram showing the configuration of the control unit in detail. The output of the six-axis force sensor 50 is an amplifier 78 and an A / D conversion circuit 8.
The input value is input to the microcomputer via 0, and the CPU 82 stores the input value in the RAM 86 at predetermined time intervals according to the count value of the timer 84. Output pulses from the rotary encoder 74 and the like are also stored in the RAM 86 via the counter 88. As will be described in detail later, the CPU 82 searches for the joint angle target value θit stored in the ROM 90 in advance in accordance with the detection parameter, obtains an angle command value θCOMM from the deviation from the detected actual angle, and Is calculated and output as a digital value. The output is converted to an analog value by the D / A conversion circuit 92 and sent to the servo driver 94, where the servo driver
At 94, it is converted to a current value and supplied to the electric motor 24 of each joint. Further, the output value of the rotary encoder is fed back to the servo driver 94 via the F / V conversion circuit 96, and forms a servo system.

FIG. 6 is a flow chart showing the operation. Referring to the drawing, first, after initializing each part in S10, the outputs of the six-axis force sensor 50 and the like are input in S12, and the walking pattern is calculated in S14. That is, the angle target value θit described above is searched for the twelve joints of the left and right legs with reference to the ROM 90. Here, the value θit is the time t of the i-th joint.
Means the target angle. The input of the parameters and the calculation of the walking pattern may be performed in advance offline and stored in a memory. Specifically, the detected actual angle θact is read, the deviation from the angle target value θit is obtained to calculate the angle command value θCOMM, and then the angle target value is converted by an appropriate method to convert the speed command value Vc of the electric motor. Is calculated and output is started. Thus, walking starts as shown in S16. That is, first, the both-leg supporting phase is entered in S18, and when the command value of the both-leg supporting phase is output, the process then proceeds to S20, in which, for example, the right-leg supporting (in this example, the left leg is a free leg) phase, and the sequence proceeds one after another. The command value will be executed. Until the execution of the command value of this phase, the landing of the free leg is detected from the output of the six-axis force sensor 50 in S22, but the execution is continued until that time. When it is confirmed that the free leg (left foot) touches the ground in S22, the process proceeds to S24 and enters the compliance control phase of the free leg (left foot).

FIG. 7 is a subroutine flowchart showing the compliance control. To explain below, first, S1
At 00, the output value of the six-axis force sensor 50 is read to detect the moment acting on the ankle around the x-axis (around a horizontal axis perpendicular to the traveling direction). As described above, the ankle joint is provided with a degree of freedom for swinging the foot in the traveling direction (pitch direction) and a degree of freedom for swinging in the left-right direction (roll direction). 24 and 26 are provided individually. Therefore, it is essentially necessary to control these two directions at the time of landing, but in the following description, only the copying operation in the traveling direction will be described for convenience of understanding. The same applies to the left-right direction.

Subsequently, the process proceeds to S102, where a virtual rotational displacement Δθ is calculated. That is, assuming a dynamic model as shown in the figure, the entire sole 54 is assumed to be suspended around the ankle 18 by a vine winding spring having a spring constant KCOMP, and the rotational displacement is proportional to the magnitude of the moment Mx. It is assumed that Δθ is performed. Proportional constant KCO
The MP is appropriately set through experiments, and this value eventually determines the responsiveness of the copying operation. The rotational displacement Δθ is obtained by back calculation from the moment Mx.

Subsequently, in S104, the angle command value θCOMM is corrected by adding the rotational displacement Δθ and the above-described angle command value θCOMM. In the control unit, the CPU 82 newly calculates the motor speed command value Vc from this value and sends it to the D / A conversion circuit 92.The converted analog value is sent to the electric motor via the servo driver 94.
Supplied to 24. At this time, the other electric motor of the ankle joint
Similar control may be appropriately performed for other motors such as the electric motor 26 or the knee joint electric motor 28.

Then, returning to the main flow chart of FIG. 6, S2
The process is continued until the time T0 is reached at 6, and thereafter S28
To enter the support phase again. The reason that the compliance control is ended at the time T0 is that the landing is originally a collisional event and does not continue for a long time.
When the two-leg support phase ends, the process proceeds to S30 and below, and then enters the left-foot support (right leg swing) phase. Thereafter, the same control is performed in S32 to S36. One cycle is completed. Similar behavior
The process is continued until it is determined in S40 that the process has been completed.

In the present embodiment, at the start of walking, walking control is performed based on the desired angle target value, but at the time when the free leg touches the ground and the moment Mx acts on the ankle joint, a virtual displacement that will bend at that moment. Assuming the angle, adding it to the intended target value to obtain a new command value, and controlling based on that value, the foot is driven in the direction to reduce the moment as a result, The landing can be imitated according to the road surface while effectively reducing the impact.

FIG. 8 is a second embodiment of the present invention showing another example of the compliance control of FIG. If the spring constant KCOMP used in the first embodiment is set to be small, the value of the rotational displacement becomes large with respect to the generated moment, the correction amount becomes large, and the familiarity becomes easy. On the other hand, if the spring constant is set to a large value, it takes time to adjust. Therefore, when it is necessary to increase the walking speed, the spring constant KCOMP is set small because the landing operation time is also shortened. As a result, the loop gain becomes large and the system may oscillate. Conversely, if the spring constant KCOMP is set large to avoid oscillation, the copying operation does not end in time and the road surface reaction force remains. This embodiment is to solve the contradictory problem. The gist of the present invention is to improve the response of the copying operation of the sole without increasing the loop gain by adding an integral term. is there.

FIG. 8 is a subroutine flow chart of FIG. 6 showing the second embodiment. After reading the moment Mx in S200 as in the first embodiment, the process proceeds to S202 to calculate the rotational displacement Δθ. That is, the moment is added to the above-mentioned proportional term.
It is calculated by integrating Mx with time and adding a value obtained by multiplying the reciprocal of a new proportional constant KCOMPI. The second proportional constant KCOMPI is set as appropriate, and the integration unit time is set to a small value.
Next, an angle command value is calculated in S204, converted into a speed command value in S206, and output.

In the case of the present embodiment, since the integral term is added, the longer the time during which the moment is acting, the larger the integral value becomes, and the moving amount becomes larger than that of the first embodiment. The copying operation can be completed in a short time.
That is, even if the first spring constant KCOMP is set relatively large in order to avoid oscillation, the integral term is added together after a certain short period of time, so that the movement amount increases, and consequently the scanning operation time decreases. Can be done.

9 and 10 show the control results of the examples shown in the first and second embodiments. FIG. 9 shows the results of the static characteristics, and FIG. 10 shows the results of the dynamic characteristics to which the idea of time is added. 9 (a) that the displacement angle increases as the spring constant decreases, and (b)
It can be seen from the proportional integral control that the gain is almost infinite. Also, in the case of the first embodiment from FIG. 10 (a), the moment and the displacement angle are balanced at a certain time and an offset remains, but the moment converges to zero from the second embodiment of FIG. 10 (b). You can understand to do.

Next, consider a case where the walking speed further increases and it becomes impossible to tolerate even a short time in the second embodiment. At this time, the next operation is performed while the copying operation is insufficient, and when the unevenness of the road surface is severe, there may be a case where it is difficult to secure walking stability. The third embodiment described below has been devised in order to deal with such a point. The gist of the third embodiment is that the direction in which compliance is performed to suppress the oscillation phenomenon (that is, the increase or decrease of the moment Mx). direction)
The point is to control the foot so that it is soft in the direction in which the foot lands on the road surface and stiff in the opposite direction, and in that the operation amount of compliance control is obtained as a motor speed command value from the beginning. Yes, the copying operation can be completed in a short time even if the moment is suddenly reduced and the copying operation is slowed down, or even if oscillation increases in the system due to the increase or decrease of the moment. It is as follows. That is, even under such conditions, the above-mentioned spring constant KCOMP can be freely set to a value suitable for absorbing impact at the time of landing.
Is the servo gain as is clear from the description so far. In the following third embodiment, a logical configuration is made using this servo gain. However, in order to avoid confusion of description, a small letter k is used instead of a capital K in the following servo gains.

FIG. 11 is a subroutine flow chart of compliance control showing the third embodiment.

First, in S300, the moment acting on the sole is read out in the same manner as in the previous embodiment group, and then, in S302 and subsequent steps, the direction and amount of the moment are corrected. That is, first, the moment detected in S302 is compared with a predetermined value MTH (for example, appropriately set to “0” or the like), and when it is determined that the detected value is smaller than the predetermined value,
Proceeding to S304, the correction moment (herein referred to as Mc) is set to zero. If it is determined in S302 that the detected value is larger than the predetermined value, that is, it is determined that the detected value is in the forward direction, the process proceeds to S306, where it is compared with a second predetermined value M0α. The second predetermined value is a value obtained by multiplying the corrected moment Mc used one cycle before by α times, for example, 0.9 times. When it is determined in S306 that the detected value is larger than the second predetermined value, the detected value is corrected as it is in S308, and when it is determined that it is smaller, the second predetermined value is set as the corrected moment in S310. That is, by going through S302 to S310, the moment can be limited to the one that changes in the positive direction, and even if the moment is in the positive direction, the damping rate can be limited when it decreases rapidly. I can do it.

Next, in S312, a motor speed command value Vcl (force control component) is calculated by multiplying the corrected moment Mc by a proportional gain kp1 appropriately set. Next, in S314, the operation value is stored for the next operation. Next, in S316, a second motor speed command value Vc2 (position control component) is calculated by multiplying the deviation between the actual angle θact of the joint and the target θit by a second proportional gain kp2 which is appropriately set. Combine the values and output. In the above, the proportional gain is set, for example, after grounding ... kp1: kp2 = 10: 16 before grounding ... kp1: kp2 = 0: 512. This is because kp1 = 0 is natural since the moment is zero during the swing phase, and since compliance control is not required, it is better that the gain is high in order for the foot to pass the target trajectory accurately. Because.

In the case of this embodiment, the moment detected in S302 is the first moment.
When it is determined that the value is smaller than the predetermined value (zero), the speed command value Vc1 of the force control component becomes zero, so that the compliance control can be performed only when the moment is in the positive direction. When it is determined in S306 that the moment has sharply decreased, the value is set to a value slightly lower than the previous moment. Can be done. Further, since the speed command value of the motor is used as the operation amount, the control speed can be increased as compared with the case where the angle command value of the motor is used as the operation amount as in the first and second embodiments. Sometimes, the copying operation can be performed with good followability.

Next, a fourth embodiment of the present invention will be described. The compliance control of the ankle joint of the walking robot is essentially to detect and control the torque (moment) of the walking joint. In the embodiments described so far, the angle or the speed command value of the motor is used as the operation amount. It takes some time to convert to torque. As described above, in order to reliably end the control within a short period of time equal to the collision at all walking speeds, it is necessary to further improve the responsiveness of the control. The fourth embodiment is intended to solve the problem, and the intention is to directly output a motor current value which is directly proportional to the torque to enhance the responsiveness.

Referring to FIG. 12, first, the moment is read out in S400, and then the current target value Ire is calculated by multiplying the moment detected in S402 by a proportional constant C appropriately set. This proportionality constant is appropriately set, but has a characteristic that the operation becomes softer when the set value is larger as described later.
Next, a current command value is calculated from S404 onward based on the relationship shown in FIG. In this embodiment, as shown in FIG. 13, the current target value is set linearly with respect to the command value, and the upper limit of the current command value is IL +
In the following, the range in which the compliance control is performed is limited to the time when the moment is substantially in the positive direction, similarly to the third embodiment. That is, in the compliance control at the time of landing, the electric motor is positively driven in a direction in which the detected moment acts, so that the moment becomes zero as a result. As described above, the harmonic reducers 38, 46 and the like are interposed, and the friction, or the friction of the motor itself, or other resistance such as viscous resistance exists,
The above-mentioned current command values are set so as to be able to resist them.

That is, first, the target value of the current is compared with the upper limit value of the command value in S404, and if the current value exceeds the upper limit value, the current value is limited to the upper limit value in S406. If not, the command value is compared with the lower limit value of the command value in S408. If it is equal to or more than the lower limit value, the target value is set as the command value in S410. Thereafter, the process proceeds to S414, and the determined current command value is output.

FIG. 14 shows a main part of a control unit according to the fourth embodiment. The difference from the previous embodiment is that the current value is controlled by a servo amplifier via a current sensor 98 provided at an appropriate position of the electric motor group. The point is that it is fed back to 100.
In this embodiment, since it is not necessary to feed back the output pulse of the encoder to the servo amplifier 100, the F / V conversion circuit is omitted.

In the case of the fourth embodiment, since the energizing current of the motor is immediately used as the operation amount, the responsiveness can be further improved. Further, the object can be realized by generating a motor torque in the same direction as the direction in which the moment acts upon landing and correcting inertia around the ankle joint, friction, viscous resistance, and the like. By changing the correction amount, the degree of softness of the compliance can be changed.
The correction amount can be changed by changing the proportional constant C or changing the upper limit of the current. If the proportionality constant is set to a large value, a large amount of current flows with respect to the generated moment, so that the foot lands flexibly, and the responsiveness is also improved. On the other hand, if the upper limit value is increased, the motor will follow a large moment, but the response will not be improved. Therefore, in actual control, by appropriately selecting these two parameters, it can be widely applied to various landing characteristics. It is possible to do. By setting the lower limit of the oscillation to a value close to zero, the direction in which compliance is performed can be limited, and this can be avoided.

Although only the second embodiment discloses the proportional integral control in the above four embodiments, the integral control may be added as appropriate in other examples.

Also, the explanation has been given by taking a bipedal walking robot as an example,
Even if there are three or more legs, it is possible to walk quietly by feeding back the road surface reaction force to the drive motor of the lowest joint axis. Further, as described above, not only the moment in the traveling direction but also the moment in the left-right direction can be similarly controlled if the degree of freedom is provided.

According to a first aspect of the present invention, there is provided a joint control apparatus comprising a servo mechanism for controlling a joint of a robot to follow a target position and performing a copying operation by changing an operation amount according to an external force acting on the robot. The joint is a joint including a foot joint of a legged walking robot having a sole at a tip, detects an external force acting on the sole, adjusts a gain of a control device so as to reduce the external force, and adjusts the Because the bottom is configured to land while following the road surface, the legged walking robot can land so as to flexibly adapt to the unevenness of the road surface, and since the impact at the time of landing is effectively reduced, the walking itself Can be stabilized, and a quiet walking operation can be realized.

The joint control device for a legged walking robot according to claim 2, wherein the proportional gain of the control device is adjusted in accordance with the moment acting on the sole of the foot, so that the magnitude of the moment acting on the sole of the foot is adjusted. Accordingly, the above-described effects can be achieved.

The joint control device for a legged walking robot according to claim 3, wherein the proportional gain and the integral gain of the control device are adjusted in accordance with the moment acting on the sole when the landing is performed. The responsiveness of the motion can be further improved, and the above-described effect can be achieved even when the walking speed increases.

The joint control device for a legged walking robot according to claim 4 is configured such that the operation amount of the control is the rotation angle of the joint. Can be achieved.

The joint control device for a legged walking robot according to claim 5 is configured such that the operation amount of the control is the rotation speed of the joint, so that the above-described effect is obtained even when the walking speed further increases. Can be achieved.

The joint control device for a legged walking robot according to claim 6 is configured such that the operation amount of the control is the driving torque of the joint, so that the above-described effect is obtained even when the walking speed further increases. Can be achieved.

The joint control device for a legged walking robot according to claim 7 is configured such that the torque generated by the actuator that drives the joint is a value corresponding to a predetermined change direction of the moment. By limiting the direction in which the moment changes, the above effect can be achieved without causing oscillation even if the compliance is further softened.

In the joint control device for a legged walking robot according to the eighth aspect, the torque generated by the actuator for driving the joint is attenuated at a predetermined rate. The phenomenon can be suppressed more effectively.

According to a ninth aspect of the present invention, in the joint control device for a legged walking robot, the actuator is connected to a rotation shaft of the joint via a power transmission unit, and the damping rate includes a frictional resistance of the power transmission unit. Since the configuration is determined based on the value, the above-described effects can be more effectively achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a joint control device for a legged walking robot according to the present invention, FIG. 2 is an explanatory diagram schematically showing the whole legged walking robot according to the present invention, and FIG. FIG. 4 is a partially cutaway front view of the leg shown in FIG. 3, and FIG. 5 is a control unit for controlling the joint drive of the legged walking robot shown in FIG. FIG. 6 is a block diagram showing details, FIG. 6 is a main flow chart showing its operation, FIG. 7 is a subroutine flow chart showing compliance control therein, and FIG. 8 is related to a second embodiment of the present invention. FIG. 6 shows a subroutine flow chart of a main routine showing compliance control, FIGS. 9 (a) and 9 (b) show control result data showing static characteristics of the first and second embodiments, and FIGS. 10 (a) and (b) ) Is the control result data which similarly shows the dynamic characteristics, and FIG. FIG. 6 is a subroutine flowchart of a main routine showing compliance control according to a third embodiment of the present invention. FIG. 12 is a subroutine of a main routine showing FIG. 6 showing compliance control according to a fourth embodiment of the present invention. FIG. 13 is a flow chart, FIG. 13 is a characteristic diagram for explaining characteristics of a current value used in the control, and FIG. 14 is a block diagram of a main part of a control unit used in the fourth embodiment. 1 ... legged walking robot, 10 ... foot, 12 ... lower leg,
14 ... thigh, 16 ... torso, 18 ... ankle, 20 ... knee, 22 ... hip, 24, 26, 28, 30, 32, 34 ... electric motor, 36 ... belt , 38,46 …… Harmonic reducer, 40
... fixed part, 42 ... rotating part, 44, 48 ... axis, 50 ... 6
Axial force sensor, 52… Frame, 54… Sole, 58… Toe, 60… Heel, 64,66… Elastic body, 70… Control unit, 72… Signal line, 74,76 ...... Rotary encoder, 7
8 …… Amplifier, 80 …… A / D conversion circuit, 82 …… CPU, 84 ……
Timer, 86… RAM, 88… Counter, 90… ROM, 92…
... D / A conversion circuit, 94 ... Servo driver, 96 ... F / V conversion circuit, 98 ... Current sensor, 100 ... Servo amplifier,

Continuation of the front page (72) Inventor Masao Nishikawa 1-4-1 Chuo, Wako-shi, Saitama Prefecture Honda R & D Co., Ltd. (56) References JP-A-61-133408 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) B25J 5/00 B62D 57/02

Claims (9)

(57) [Claims] 1. A joint control device comprising a servo mechanism for controlling a joint of a robot to follow a target position and performing a copying operation by changing an operation amount according to an external force acting on the robot, wherein the joint has a sole at a tip thereof. A joint including the ankle joint of a legged walking robot having an external force acting on the sole, adjusting the gain of a control device such that the external force is reduced, and causing the sole to follow the road surface. A joint control device for a legged walking robot, wherein the joint control device is configured to land while landing. 2. The joint control device for a legged walking robot according to claim 1, wherein a proportional gain of the control device is adjusted according to a moment acting on the sole portion when landing. 3. The joint control of a legged walking robot according to claim 1, wherein a proportional gain and an integral gain of a control device are adjusted in accordance with a moment acting on the sole portion when landing. apparatus. 4. The joint control device for a legged walking robot according to claim 2, wherein an operation amount of the control is a rotation angle of the joint. 5. The joint control device for a legged walking robot according to claim 2, wherein the operation amount of the control is a rotational speed of the joint. 6. The joint control device for a legged walking robot according to claim 2, wherein an operation amount of the control is a driving torque of the joint. 7. The legged walking robot according to claim 2, wherein the torque generated by the actuator driving the joint is a value corresponding to a predetermined change direction of the moment. Joint control device. 8. The system according to claim 2, wherein the torque generated by the actuator driving said joint is attenuated at a predetermined rate.
Item 8. The joint control device for a legged walking robot according to any one of items 7 to 7. 9. The power transmission system according to claim 9, wherein the actuator is connected to a rotation shaft of the joint via power transmission means, and the damping rate is determined based on a value including a frictional resistance of the power transmission means. The joint control device for a legged walking robot according to claim 8.