JP2003291082A - Multi-joint leg control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-joint leg control device capable of enhancing the locating accuracy of each join leg using a low-cost speed reducer. <P>SOLUTION: An external restraining force 18 in the opposite direction to the rotation of the drive shaft 15 of the speed reducer 14, or an external restraining force 18 in the same direction as the rotation of the drive shaft 15 of the speed reducer 14 and larger than the torque of the drive shaft 15 of the speed reducer 14, is loaded on a frame 17 for driving. This can eliminate the influence of the backlash of the speed reducer 14, and it is possible to enhance the locating accuracy of the joint leg. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for controlling an articulated leg used in a robot or the like, and more particularly, to an articulated leg control device capable of performing highly accurate positioning control while suppressing the occurrence of backlash.

[0002]

2. Description of the Related Art In recent years, robots have been actively developed, and many robots having articulated legs so as to perform more complicated movements have appeared.

FIG. 7 is a block diagram showing a portion (hereinafter referred to as a drive unit) for driving the articulated leg in the conventional articulated leg control device. This drive unit includes a motor 11, a motor shaft 12, and an encoder 1 connected to the motor shaft 12.
3, a speed reducer 14 that reduces the rotation of the motor shaft 12, and a final stage drive shaft 15 that drives the joint leg.

When the drive shaft 15 at the final stage is rotated by relaying the speed reducer 14 by the rotation of the motor 11, the speed reducer 14
Backlash occurs due to the play of gears. When backlash occurs, the motor shaft 12 and the final stage drive shaft 1
5 causes a rotation error of the control amount, which causes a decrease in the precision of the control amount. A harmonic drive type speed reducer is known as a speed reducer capable of reducing the backlash.

FIG. 8 is a block diagram showing a drive unit of an articulated leg capable of correcting the rotation error of the drive shaft 15 at the final stage. This drive unit is different from the drive unit shown in FIG. 7 only in that an encoder 16 is connected to the drive shaft 15 at the final stage. By disposing the encoder on the final stage drive shaft 15 in addition to disposing the encoder 13 on the motor shaft 12, it is possible to detect the rotational error of the final stage drive shaft 15 and correct the rotational error. Becomes

[0006]

However, in the drive section of the articulated leg shown in FIG. 7, in order to reduce the backlash generated by the play of the gear of the reduction gear 14 and improve the positioning accuracy, the harmonic drive type is used. Although a speed reducer such as a speed reducer is required, it is very expensive and has a large size, so that there is a problem that the cost of the drive unit becomes high and the size becomes large.

Further, in the drive unit of the articulated leg shown in FIG. 8, when the drive shaft 15 at the final stage is not moved to a predetermined position simply due to the influence of twisting of the transmission system or backlash,
The motor 11 is driven by the correction amount calculated from the measured values of the encoders 13 and 16 to move the drive shaft 15 to a predetermined position. However, when an external load is applied, a backlash rotation error occurs. Even if the motor 11 is rotated to forcibly correct this rotation error, the drive shaft 15 does not rotate normally due to the dead zone region generated by backlash, so that an oscillation phenomenon occurs near the stop position, and positioning accuracy and stability are improved. There was a problem that was worse.

The present invention has been made to solve the above problems, and a first object of the present invention is to provide multi-joint leg control capable of improving the positioning accuracy of joint legs by using an inexpensive speed reducer. It is to provide a device.

A second object is to more accurately control the motor control amount even when a sudden force is applied to the device in which the articulated leg control device is arranged or the device walks on an inclined surface. An object is to provide a multi-joint leg control device that can be controlled.

[0010]

According to one aspect of the present invention, an articulated leg control device includes a motor, an encoder connected to the motor shaft of the motor, and a motor shaft of the motor. The speed reducer that reduces the speed, the position detector that is connected to the drive shaft of the speed reducer, the drive frame that is connected to the drive shaft of the speed reducer, and the drive frame that is opposite to the rotation direction of the drive shaft of the speed reducer. Direction, or means for applying an external binding force in the same direction as the rotation direction of the drive shaft of the speed reducer and larger than the rotation force of the drive shaft of the speed reducer,
A motor control unit that controls the rotation of the motor based on the outputs from the encoder and the position detector.

An external restraining force is applied to the drive frame in a direction opposite to the rotation direction of the drive shaft of the reduction gear, or in the same direction as the rotation direction of the drive shaft of the reduction gear and larger than the rotation force of the drive shaft of the reduction gear. Since the external restraint force is applied, the influence of backlash of the reduction gear can be eliminated, and the positioning accuracy of the joint leg can be improved.

[0012] Preferably, the means for applying the external restraint force applies the external restraint force to the drive frame by the weight of the device in which the articulated leg control device is arranged.

Therefore, it is possible to apply an external restraining force to the drive frame without adding a complicated mechanism.

Preferably, the articulated leg controller further comprises:
The motor control device includes a sensor that detects acceleration or angular velocity, refers to an output from the sensor, calculates an error of an external binding force, and controls the rotation of the motor.

Therefore, even when a sudden force is applied to the device in which the articulated leg control device is arranged or the device walks on an inclined surface, the control amount of the motor can be controlled more accurately. It will be possible.

[0016] Preferably, the means for applying the external restraint force applies the external restraint force to the drive frame by a torsion spring provided between the reduction gear and the drive frame.

Therefore, it becomes possible to generate a stable external restraint force on the drive frame.

Preferably, the means for applying an external restraint force applies the external restraint force to the drive frame by a tension spring provided between two drive frames connected to the drive shaft of the speed reducer. .

Therefore, it becomes possible to generate a stable external restraint force on the drive frame.

Preferably, the position detector is composed of an encoder. Therefore, the resolution of the position detector can be increased, and the positioning accuracy of the drive shaft of the speed reducer can be improved.

[0021] Preferably, the position detector is constituted by a potentiometer. Therefore, the position detector can be downsized and the sensing circuit can be simplified.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION (Embodiment 1) First, the cause of backlash will be described with reference to FIG. Straight lines 21 and 22 in FIG. 1 indicate the relationship between the rotation amount of the motor shaft and the rotation amount of the final stage drive shaft of the reduction gear (hereinafter referred to as the reduction gear drive shaft). In the graph of FIG. 1, it is defined that when the motor shaft is rotated in the increasing direction (clockwise direction), the reduction gear drive shaft is also rotated in the increasing direction.

Backlash is a dead zone region due to play that occurs when a speed reducing mechanism that reduces the speed by a gear or the like is used. When the motor shaft is rotated only in the increasing direction, the drive shaft of the speed reducer increases like the straight line 21. Rotate in the direction.

When the motor shaft is rotated in the increasing direction and then stopped at the position P1, the speed reducer drive shaft stops at the position Q1. Next, when the motor shaft is rotated in the decreasing direction, the rotation amount of the reduction gear drive shaft does not move on the straight line 21 due to the backlash of the reduction gear on the motor shaft side.
The speed reducer drive shaft is stopped at the position Q1 until the motor shaft is rotationally moved to the position P2, that is, the motor shaft is rotationally moved by the amount of the backlash 23 on the motor shaft side, and then the rotation amount of the speed reducer drive shaft is linear. Move on 22 in the decreasing direction.

Next, when the rotation of the motor shaft is stopped at the position P3, the reduction gear drive shaft is stopped at the position Q2. Here, when the motor shaft is rotated in the increasing direction, the speed reducer drive shaft is driven by Q until the motor shaft is rotationally moved to the position P4 due to the backlash of the speed reducer gear on the motor shaft side.
After stopping at position 2, the speed reducer drive shaft is rotationally moved again according to the straight line 21.

That is, the motor shaft is P1 → P2 → P3 →
When rotating in the order of P4 → P1, the drive shaft of the reduction gear moves from point A → B → C → D → A due to the influence of backlash.

From the above, in order to suppress the influence of backlash while ensuring the repetitive positioning accuracy, it is necessary to rotate the motor shaft in a constant direction from a position where there is no backlash. A method of using a harmonic drive type speed reducer is widely known as a method of suppressing backlash by a speed reducing mechanism, but has the drawbacks of being expensive and large in size as described above.

FIG. 2 is a block diagram showing a schematic configuration of the articulated leg controller for a robot according to the first embodiment of the present invention. This articulated leg control device includes a position detector 10,
A motor 11, a motor shaft 12, an encoder 13 connected to the motor shaft 12, a speed reducer 14 that reduces the rotation of the motor shaft 12, a speed reducer drive shaft 15 that drives the joint leg,
It includes a drive frame 17 such as a joint leg to which an external restraining force 18 is applied, and a motor control unit 19.

A motor shaft encoder 13 and a speed reducer 14 are connected to the motor shaft 12 of the motor 11. The position detector 10 and the drive frame 17 are connected to the speed reducer drive shaft 15. An external restraining force 18 is applied to the drive frame 17 from one direction.

The motor control unit 19 generates a control signal for driving the motor 11 according to the control amount from the detection results of the motor shaft encoder 13 and the position detector 10 and the control amount of the external restraining force 18. And outputs it to the motor 11.

The motor shaft encoder 13 includes the motor 11
The backlash does not occur because it is mounted by directly connecting to the motor shaft. The position detector 10 is a reduction gear drive shaft 1
It is for detecting the rotational state and rotational position of the motor 5, and is directly connected to the drive frame 17 and the speed reducer drive shaft 15.

In this state, when the motor 11 is rotated in a single direction, the speed reducer drive shaft 15 rotates in accordance with the speed reduction ratio of the speed reducer 14. However, when the motor 11 rotates in the reverse direction, FIG. Backlash 2 as explained using
3 and 24 occur, and the positioning accuracy for the control amount of the motor 11 cannot be secured.

However, when an external restraining force 18 is applied to the drive frame 17 directly connected to the reduction gear drive shaft 15 in one direction with respect to the rotation shaft, the reduction gear drive shaft 15 is rotated in a direction. The opposite force will always be generated. Then, when the motor 11 reversely rotates in the middle, the reduction gear drive shaft 15 momentarily rotates in the same direction as the rotation direction of the motor 11 due to the twist of the reduction gear drive shaft 15. As a result, the relationship between the motor shaft 12 and the speed reducer drive shaft 15 is always a one-to-one relationship on the straight line 21 or 22 in FIG.
The positioning accuracy can be secured.

The position detector 10 may be an incremental encoder that outputs a two-phase pulse such as an optical type, a magnetic type, or a mechanical type, or an absolute encoder that outputs an absolute position in one rotation. As described above, when an encoder is used for the position detector 10, the resolution of the encoder itself can be increased, so that the positioning accuracy of the reduction gear drive shaft 15 can be increased.

When a variable resistance potentiometer is used for the position detector 10, the position detector 10 can be downsized and the sensing circuit can be simplified. Further, since the absolute position can be easily detected from the resistance value of the potentiometer, the motor controller 17 can easily control the motor 11.

FIG. 3 is a diagram for explaining a vector generated when the articulated leg control device according to the first embodiment of the present invention is applied to the leg of a robot. In the present embodiment, as means for generating the external restraining force 18,
Use the robot's own weight. As shown in FIG. 3, a force of a vector 39 is generated in the gravity direction from the gravity center position 38 of the robot due to the weight of the robot. By the restraining force of the vector 39, the drive shafts 35a to
The binding force of each of the arrows 34a to 34f is generated in the portion 35c.

That is, the restraining force 39 applies a force 34a to the drive frame 32a around the drive shaft 35a connecting the body portion 31 of the robot and the drive frame 32a. Joins the body 31 of the robot. Similarly, a force 34c is applied to the drive frame 32a around the drive shaft 35b, and a force 34d equivalent thereto is applied to the drive frame 32b. Similarly, a force 34e is applied to the drive frame 32b about the drive shaft 35c.
Is applied, and a force 34f, which is equivalent thereto and in the opposite direction, is applied to the foot 32c. In this way, the restraint force 39 due to its own weight is divided into each vector, and the restraint force with respect to the drive shaft of each joint can be generated.

Further, when the present invention is applied to the arm portion of the robot, it is possible that the external restraining force is insufficient only by the weight of the arm portion of the robot. However, since a large external restraint force is generated when the work of lifting a load or the like is performed by the arm portion, a sufficient restraint force can be generated on the drive shaft of each joint of the arm portion.

The body 31 of the robot has an acceleration
The sensor 40 for detecting the angular velocity and the like are provided, and the current trunk position of the robot can be accurately grasped. As a result, the external restraining force 18 applied to the reduction gear drive shaft 15 can be calculated more accurately according to the rotation angle of each joint of the articulated leg portion, and the motor for the backlash correction amount of the reduction gear drive shaft 15 can be calculated. It is possible to accurately control the control amount of 11.

Since the position of the center of gravity of the robot, the weight, the length of each leg and the relative positional relationship are already known at the designing / manufacturing stage, the position detector 10 causes the current motor drive shaft 1 to move.
If the rotation angle of 2 is detected, the value of the rotation angle at each joint can be calculated. Therefore, when the restraining force of the vector 39 is generated due to its own weight, the vectors 34a to 3
The binding force of 4f can be calculated. When no sudden force is applied to the robot from the outside or when the robot walks on a horizontal plane, the binding force can be calculated in this way.

However, when a sudden force is applied from the outside or when the robot walks on an inclined surface, the constraint force of the vector 39 due to its own weight may deviate from the expected value. In such a case, by providing the acceleration / angular velocity detection sensor 40, it is possible to detect the current torso position of the robot, that is, the current tilt posture of the robot itself, so that the direction of the vector 39 can be easily calculated. can do. If you know the direction of vector 39,
Since the binding force of the vectors 34a to 34f can be easily calculated by the method described above, the reduction gear drive shaft 15
It becomes possible to more accurately control the control amount of the motor with respect to the backlash correction amount.

As described above, when the external restraint force 18 is used, when the external restraint force is applied in the direction opposite to the rotation direction of the speed reducer drive shaft 15, and when the reducer drive shaft 15 is stopped. In this case, the positioning accuracy can be ensured as described above. In addition, the motor control unit 19
The rotation control of the motor 11 by means of can also use a simple control method.

On the other hand, in the case where the reduction gear drive shaft 15 is rotated in the same direction as the external binding force 18, and the rotational force of the reduction gear drive shaft 15 by the motor 11 is smaller than the external binding force 18, The relationship of the straight line 21 or the straight line 22 shown in 1 can be maintained. However, when the rotational force of the reduction gear drive shaft 15 by the motor 11 is larger than the external constraint force 18, the transition from the straight line 21 to the straight line 22 or the straight line 2
The transition from 2 to straight line 21 occurs. That is, since the vehicle passes through the section where the backlash 23 or 24 occurs,
The stability of motor control may be impaired. A method by which the motor control unit 19 maintains the stability of motor control even in such a case will be described below.

FIG. 4 is a diagram for explaining the motor control unit 19 of FIG. 2 in more detail. The motor control unit 19
It includes a sensor input circuit 61, a backlash and drive shaft rotation angle detection circuit 62, an external binding force setting constant 63, and a control amount calculation circuit 64. In FIG. 4, the drive control shaft 1
Although the motor control units 1 to N are provided respectively corresponding to .about.N, the motor control units 1 and N have the same configuration and function, and therefore only the motor control unit 1 and the drive control shaft 1 will be described. Since the drive control shaft corresponds to the part of the joint leg shown in FIG. 2 excluding the motor control unit 19, detailed description thereof will not be repeated.

First, the sensor input circuit 61 inputs signals from the encoder 13 and the position detector 10 to detect the position. The backlash and drive shaft rotation angle detection circuit 62 detects the current rotational position of the motor 11 and the amount of backlash based on the position detection result of the sensor input circuit 61 and the position detection result of another sensor input circuit (not shown).

As an example of the method of detecting the amount of backlash,
When the motor 11 is rotated in a fixed direction from the position where the influence of backlash is eliminated and then the motor 11 is reversely rotated by the same amount, the value of the encoder 13 returns to the original value.
The value of the position detector 10 is different before and after the motor rotation, and a method of detecting the positional deviation which is the difference as the backlash amount can be mentioned.

The backlash amount changes with time due to wear of gears, etc., but when used in units of several days, almost no change with time is observed. Therefore, the backlash amount is detected at the time of initial setting when the articulated leg control device is started, and the value is stored in an external storage unit such as a memory for use.

The control amount calculation circuit 64 uses the backlash and drive shaft rotation angle output from the backlash and drive shaft rotation angle detection circuit 62 and the preset external binding force setting constant 63 to drive the speed reducer. The control signal such as the rotation speed and the rotation amount of the motor 11 is output to the motor control amount output circuit 65 so that the shaft 15 reaches the target position to be moved. As a result, the motor 11 makes a predetermined rotation,
It becomes possible to perform positioning.

As described above, the external restraining force (decreasing direction) in the direction opposite to the rotating direction (increasing direction) of the motor 11 is used.
When the above works, it is possible to perform the one-to-one positioning on the straight line 21 in FIG. When it is desired to move the rotation of the reduction gear drive shaft 15 from the position Q3 to the position Q1, the rotation of the motor shaft 12 moves from the position P3 to the position P1. At this time, the motor 11
Since the external restraining force 18 acts in the direction opposite to the direction in which the gear rotates, that is, in the decreasing direction, the reduction gear drive shaft 15 can be moved without the influence of backlash.

On the other hand, when it is desired to move the rotation of the speed reducer drive shaft 15 from the position Q1 to the position Q3, the rotation of the motor shaft 12 moves from the position P1 to the position P3. At this time, the motor 11
The direction of rotation of the motor 11 and the direction of the external restraining force 18 are the same, but when the speed of rotation due to the external restraining force is faster than the rotation speed of the motor 11, the speed reducer drive shaft 15 is affected without backlash. Can be moved.
However, when the rotation speed of the motor 11 is faster than the speed at which the motor 11 tries to rotate due to the external restraining force, in the process of transitioning from P1 to P3 in the section where the rotation speed of the motor 11 is high, first, from the point A to the point B. Transition. The amount of movement between AB corresponds to the amount of backlash on the motor shaft 12 side.

Next, the line 22 is rotated to the point F, that is, the position P4. Here, when the rotation speed of the motor 11 becomes slower than the rotation speed by the external restraining force 18, the motor transits from the point F to the point D and moves on the straight line 21 again. The amount of movement between the FDs corresponds to the amount of backlash on the reducer drive shaft 15 side. When the rotation of the motor shaft 12 stops at point E, that is, the position of P3, the motor shaft 12 stops at the position of Q3 on the speed reducer drive shaft 15 side. in this way,
By controlling the motor 11, it becomes possible to perform smooth positioning control in consideration of backlash.

If the motor shaft 12 is directly rotationally moved from the position P1 to the position P3 without using such a control method, the final positioning accuracy can be ensured. However, since the straight line 22 makes a direct transition to the straight line 21 due to backlash, the speed reducer drive shaft 15 vibrates in the vicinity of Q3, and it takes a long time to stably stop.

As described above, according to the articulated leg control device of the present embodiment, the drive frame 17 is provided with the external restraining force 18 in the direction opposite to the rotation direction of the speed reducer drive shaft 15.
Alternatively, since the external restraining force 18 having the same direction as the rotation direction of the speed reducer drive shaft 15 and larger than the rotation force of the speed reducer drive shaft 15 is applied, the influence of the backlash due to the speed reducer 14 can be eliminated. It has become possible to improve the positioning accuracy of the joint leg. Further, since it is not necessary to use a harmonic drive type speed reducer, it is possible to configure the articulated leg control device using an inexpensive speed reducer, and it is possible to reduce the size.

Further, when an encoder is used for the position detector 10, the resolution of the encoder itself can be increased, so that the positioning accuracy of the reduction gear drive shaft 15 can be increased. When a potentiometer of variable resistance type is used for the position detector 10, the position detector 1
It has become possible to reduce the size of the sensor and to simplify the sensing circuit.

Further, since the robot's own weight is used as the external restraining force 18, it is possible to apply the external restraining force 18 to the drive frame 17 without adding a complicated mechanism.

Since the robot is provided with the acceleration / angular velocity detection sensor 40, even if a sudden force is applied to the robot from the outside or the robot walks on an inclined surface, the robot itself. It is possible to detect the current tilt posture of the vector and the like, and it is possible to easily calculate the direction of the vector 39. Therefore, the external restraint force at each joint can be easily calculated, and the control amount of the motor with respect to the backlash correction amount of the reduction gear drive shaft 15 can be controlled more accurately.

(Embodiment 2) FIG. 5 is a block diagram showing a schematic configuration of a robot articulated leg control apparatus according to Embodiment 2 of the present invention. The configuration of the articulated leg control device for a robot according to the present embodiment is different from the configuration of the articulated leg control device for a robot according to the first embodiment shown in FIG. The only difference is that a torsion spring 51 and fixing pins 50a and 50b for fixing the torsion spring 51 are provided between the drive shaft 14 and the drive frame 17. Therefore, detailed description of overlapping configurations and functions will not be repeated.

The torsion spring 51 has the fixing pins 50a and 5a.
Since it is fixed by 0b, the external restraining force 18 can be generated by the torsional force of the torsion spring 51. This makes it possible to generate a more stable restraining force than when the external restraining force 18 is generated using the robot's own weight.

FIG. 6 is a diagram showing another example of the joint leg of the robot according to the second embodiment of the present invention. In this joint leg, the tension spring 52 is provided between the drive frames 17a and 17b mounted around the reduction gear drive shaft 15.
Is provided. The external restraining force 18 is generated by the tension of the tension spring 52. This makes it possible to generate a more stable restraining force than when the external restraining force 18 is generated using the robot's own weight.

As described above, according to the articulated leg control apparatus of the present embodiment, the external restraining force 18 is generated by the torsion spring 51 or the tension spring 52. In addition to the effect, it becomes possible to generate a stable restraining force as compared with the case where the external restraining force 18 is generated by utilizing the own weight of the robot.

The embodiments disclosed this time must be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[0062]

According to one aspect of the present invention, the drive frame is provided with an external restraining force in a direction opposite to the rotation direction of the drive shaft of the reduction gear, or in the same direction as the rotation direction of the drive shaft of the reduction gear. Since the external restraint force larger than the rotational force of the drive shaft of the reduction gear is applied, the influence of backlash of the reduction gear can be eliminated, and the positioning accuracy of the joint leg can be improved.

Further, since the means for applying the external restraint force applies the external restraint force to the drive frame by the own weight of the device in which the articulated leg control device is arranged, without adding a complicated mechanism, It became possible to apply external restraint force to the drive frame.

The articulated leg control device further includes a sensor for detecting acceleration or angular velocity, and the motor control device refers to the output from the sensor to calculate the error of the external binding force to control the rotation of the motor. Therefore, even when a sudden force is applied to the device in which the articulated leg control device is arranged or when walking on an inclined surface, it becomes possible to control the motor control amount more accurately. It was

Further, since the means for applying the external restraint force applies the external restraint force to the drive frame by means of the torsion spring provided between the speed reducer and the drive frame, the drive frame is stabilized. It became possible to generate external restraint force.

Further, since the means for applying the external restraint force applies the external restraint force to the drive frame by the tension spring provided between the two drive frames connected to the drive shaft of the speed reducer. , It became possible to generate a stable external restraint force on the drive frame.

Further, since the position detector is composed of an encoder, the resolution of the position detector can be increased and the positioning accuracy of the drive shaft of the speed reducer can be improved.

Since the position detector is composed of a potentiometer, it is possible to downsize the position detector and simplify the sensing circuit.

[Brief description of drawings]

FIG. 1 is a diagram for explaining the cause of backlash.

FIG. 2 is a block diagram showing a schematic configuration of a robot articulated leg control device according to the first embodiment of the present invention.

FIG. 3 is a diagram for explaining a vector generated when the articulated leg control device according to the first embodiment of the present invention is applied to a leg of a robot.

FIG. 4 is a diagram for explaining the motor control unit 19 shown in FIG. 2 in more detail.

FIG. 5 is a block diagram showing a schematic configuration of an articulated leg controller for a robot according to a second embodiment of the present invention.

FIG. 6 is a diagram showing another example of the joint leg of the robot according to the second embodiment of the present invention.

FIG. 7 is a block diagram showing a portion that drives an articulated leg in a conventional articulated leg control device.

FIG. 8 is a block diagram showing a drive unit of an articulated leg capable of correcting a rotation error of the drive shaft 15 at the final stage.

[Explanation of symbols]

10 position detector, 11 motor, 12 motor shaft, 1
3, 16 encoder, 14 speed reducer, 15 speed reducer drive shaft, 17 drive frame, 19 motor control unit, 5
0a, 50b fixed pin, 51 torsion spring, 52 tension spring, 61 sensor input circuit, 62 backlash and drive shaft rotation angle detection circuit, 63 external constraint force setting constant, 64 control amount calculation circuit.

Claims (7)

[Claims] 1. A motor, an encoder connected to a motor shaft of the motor, a speed reducer connected to the motor shaft of the motor to reduce the rotation of the motor, and a drive shaft of the speed reducer. A position detector, a drive frame connected to the drive shaft of the speed reducer, an external binding force in the drive frame in a direction opposite to the rotation direction of the drive shaft of the speed reducer, or a drive shaft of the speed reducer. Means for applying an external restraint force that is in the same direction as the rotation direction of the drive shaft and is larger than the rotational force of the drive shaft of the speed reducer, and the rotation of the motor based on the outputs from the encoder and the position detector. An articulated leg control device including a controlling motor control unit. 2. The multi-joint according to claim 1, wherein the means for applying the external restraint force applies the external restraint force to the drive frame by its own weight of the device in which the articulated leg control device is arranged. Leg control device. 3. The multi-joint leg control device further includes a sensor for detecting acceleration or angular velocity, and the motor control device refers to an output from the sensor to calculate an error of the external restraining force to calculate the error. The articulated leg control device according to claim 1 or 2, which controls rotation of a motor. 4. The means for applying the external restraint force applies the external restraint force to the drive frame by means of a torsion spring provided between the speed reducer and the drive frame. The articulated leg control device described. 5. The means for applying the external restraint force applies the external restraint force to the drive frame by a tension spring provided between two drive frames connected to a drive shaft of the speed reducer. The articulated leg control device according to claim 1, which is loaded. 6. The articulated leg control device according to claim 1, wherein the position detector is composed of an encoder. 7. The articulated leg control device according to claim 1, wherein the position detector is configured by a potentiometer.