JPH0741556B2 - Bilateral master-slave manipulator reaction force detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention returns the external force received by the slave arm to the master arm as a reaction force, so that the operator can sense the force or torque acting on the slave arm. It is useful for a bilateral master-slave manipulator that can operate the master arm while feeling.

B. SUMMARY OF THE INVENTION The present invention is a reaction force detecting method in which a motor torque is erased by a control system so that a motor torque generated when a slave arm is moved is not returned to a master arm as a reaction force. Is.

C. Conventional Technology The present applicant has already proposed an operating force detection device (Japanese Patent Publication No. 58-2800) for detecting the operating force of a manipulator. This will be described below.

In FIG. 2, reference numeral 1 denotes a manipulator, which is operated and controlled by remote operation. Reference numeral 2 denotes a shoulder portion for supporting the upper arm portion 3, the lower arm portion 4 and the like, which is normally equipped on a traveling carriage (not shown) and the like. Upper arm 3,
The lower arm portion 4 is configured to be bendable by the respective connecting portions (joint portions) 5 and 6, and is provided by the joint portions 7 and 8 provided at appropriate positions of the respective arm portions 3 and 4. , Is configured to be rotatable. A wrist portion 10 having a fingertip portion 9 is attached to the tip of the lower arm portion 4 at the tip thereof.

An actuator 11 as shown in FIG. 3 is internally provided in each of the joints 5, 6, 7, and 8. In this example, the joints 7 and 8 that perform a rotating action are exemplified. There is. In the figure, reference numeral 12 is a drive device such as an electric motor or a hydraulic or pneumatic motor, which is provided internally in the tubular main body 13 on the drive side of the joints 7 and 8. Reference numeral 14 denotes a speed reducer provided integrally with or linked to the drive unit 12, and an output shaft 15 thereof has an actuating member (driven body) 16 on the driven side fixed via a key 17. It is provided as a costume.
The output shaft 15 is supported by a substantially annular bracket 18 fixedly mounted on the speed reducer 14 via bearings 19 and 20. The drive device 12 and the reduction gear device 14 are rotatably supported by boss portions 21 and 22 provided on the inner peripheral surface of the drive side main body 13 via bearings 23 and 24. The bearing 24 supporting the speed reducer 14 side is provided between the bracket 18 and the boss portion 22. A part of the outer peripheral surface of the bracket 18 is provided with a protruding portion (operation detecting member) 25 that protrudes in the inner peripheral surface direction of the drive side main body 13, and the protruding portion 25 is a bracket in the drive side main body 13. Space of C-shaped support member 26 arranged concentrically with 18
It is provided by inserting it inside 27. Support member formed in C shape
26 is a fastener 29,29 such as a countersunk screw on one end 28 side.
While being fixedly provided to the inner peripheral surface 30 of the drive side main body 13 via the, the other end 31 side is provided as a free end. Further, the supporting member 26 is provided by being constituted by an elastic member such as a steel plate, and both side surfaces (inner and outer peripheral surface sides) thereof.
At the inner peripheral surface 30 of the drive-side main body 13 and the bracket 18
The space portion 27 can be freely widened and narrowed by the gap portions 33 and 34 provided between the space portion 27 and the outer peripheral surface 32.

At the fixed end 28 and the free end 31 of the support member 26, an operating force detection device 35 for detecting an operating force at the time of operation by the manipulator in cooperation with the projecting portion 25 is mounted and provided. As shown in FIG. 4, for example, the operating force detecting device 35 includes a detecting member (sensor) 36 for detecting the operating force and a pressing force adjusting member 38 for pressing the projecting portion 25 via the steel ball 37. It is configured and provided.
The detection member 36 is composed of, for example, a load meter, and is mounted in the recess 39 provided in the surface portion corresponding to the protrusion 25 at the fixed end portion of the support member 26. Detection unit 40 of the detection member 36
Is provided so as to be able to come into contact with one side surface of the projecting portion 25, and the load is detected by pressing the detecting portion 40. The detection unit 40 is provided at a position separated from the axis of the output shaft 15 by a constant distance R. Therefore, the load detected via the detection unit 40 can be detected as the operating force (operating torque). The steel ball 37 and the pressure adjusting member 38 are mounted and provided in a hole (screw hole) 41 provided in the free end 31 on the same straight line as the axis of the recess 39, and the pressing force adjusting member 38 is , Is screwed into the hole 41. The steel ball 37 is always brought into contact with the projecting portion 25 via the pressing force adjusting member 38, and is configured to be able to press the detecting portion 40 via the projecting portion 25. The pressing force for pressing the detection unit 40 can be freely performed by operating the pressing force adjusting member 38. The detection member 36 is composed of, for example, a diffusion type semiconductor pressure exchanger. The bracket 18 is not limited to being mounted on the speed reducer 14 side, and it goes without saying that the bracket 18 may be mounted and provided at a spatially vacant place, for example, at an appropriate position on the drive device 12 side. .

The operation of this device having the above configuration will be described. Operations such as maintenance work and replacement work are remotely operated by the fingertip portion 9 of the wrist portion 10. Before the work, the operating force detection device 35 is set. That is, a constant preload is applied to the detection member 36 via the pressing force adjusting member 38 and the steel ball 37. For example, if you want to detect a similar operating torque in either forward or reverse rotation direction, preload (load) up to 1/2 of the rated load of the detection member 36.
Just add. When applying the preload, the pressing force adjusting member 38 may be gradually screwed in. Pressing force adjusting member
When 38 is screwed in, the space of the space 27 is widened, and elastic force (restoring force) is stored in the support member 26 accordingly, and this elastic force preloads the detection unit 40 via the protrusion 25. Because. Therefore, if the rated load of the detection member 36 is Pkg, for example, a torque of ± 1 / 2P · R can be detected. This preload does not necessarily need to be set to the rated load 1/2, and is set within the range of, for example, about 10% to 90% of the detection member 36, and the set point therein is the reference point (output of the amplifier) (not shown). = 0), it is also possible to detect the operating torque in the forward and reverse directions. Preload detection of member 36 rating
A value of 10% or more prevents the detection accuracy from decreasing due to the vibration of the detection member 36 and the steel ball 37, and
This is for preventing the contact portion of the detection member 36 and the steel ball 37 from being worn due to vibration.

If work is performed using the operating force detection device 35 set as described above, the load resistance during the work can be detected as the load torque, and the work force (operating torque) in both the forward and reverse rotation directions can be accurately measured. Can be detected. Moreover, in the case of this configuration, since the detection of the operating force is not affected by the reduction of the mechanical efficiency in the deceleration process of the reduction gear transmission 14, the operating force can be detected extremely accurately. Further, the actuating force detection device 35 can be installed in an appropriate space member inside the tubular drive side main body 13, and the detection member 36 is also constituted by a simple load meter. 3 and 4 etc. can be compactly configured with extremely thin arms. In addition, since there is no rattling or backlash in the operating force detection device 35 even during reverse rotation, accuracy is guaranteed. Moreover, the stability against long-term use is extremely good, and there are no instability factors such as strain gauges due to long-term use. In addition, even if the driving device 12 such as a small and lightweight high speed motor is greatly decelerated and used, no inconvenience occurs in the detection and adjustment of the operating torque, so that the device can be made smaller and more powerful.

In particular, in this device, the C-shaped support member 26 is fixed only at one end portion 28, which has a small displacement, and
Since the portion in which the bending occurs is prevented from contacting with other portions through the gaps 33 and 34, hysteresis is small even with variations in bending and the like, and stable detection accuracy can be obtained. Moreover, since the support member 26 can utilize an appropriate space in the drive-side main body 13, it is possible to achieve a remarkable effect such that the support member 26 can be assembled while being made compact.

The bilateral master-slave manipulator manufactured by the applicant of the present invention employs a detection structure similar to that of the above-described operating force detection device for detecting the operating force. FIG. 5 shows its schematic configuration. DC motor in FIG.
100 (corresponding to the drive device 12 in FIGS. 3 and 4; corresponding members are also shown in parentheses below) is provided in the drive arm 101 (corresponding to the tubular body 12), and The stator 100a is rotatably supported by the drive arm 101 via a bearing B ₁ . DC motor 100
A speed reducer 102 (corresponding to the speed reducer 14) is connected to the stator 100a and the casing 102a of the speed reducer 102 are fixed, and the output shaft 100b of the motor is coupled via the coupling C to one speed reducer shaft. The reduction gear shaft 102c is connected to the driven arm 103 (corresponding to the operating member 16). The reduction gear 102 is further provided with bearings B ₂ and B ₃ and a reduction gear mechanism G. And DC motor 10
The 0 and the speed reducer 102 form a geared servomotor.

The drive arm 101 is provided with an elastic material 104 (corresponding to the support member 26), and the elastic force of the elastic material 104 causes the stator 100 to move.
The rotation of a is restricted. Therefore, the rotation angle of the stator 100a falls within a predetermined range in the positive and negative directions centering on a fixed position. A detection sensor 105a such as a load cell or a torque sensor is installed between the elastic member 104 and the stator 100a, and the installation position 12 is located at a position radially extended from the axis of the output shaft 100b to a distance R.

The principle of force detection by the configuration of FIG. 5 described above will be briefly described below.

(I) When the torque received by the reduction shaft 102c when an external force is applied to the tip of the slave arm is Tl, the force is transmitted to the casing 102a → stator 100a → detection sensor 105, and the detection sensor 105 And outputs a voltage corresponding to it.

(Ii) On the other hand, a current is passed through the DC motor 100 and the output shaft 100b
When a torque of T _m is generated by, the stator 100a receives the reaction force and acts on the detection sensor 105. And outputs a voltage corresponding to it.

As described above, in the case of the mechanism shown in FIG. 5, the force signal output from the detection sensor 105 includes the influence of the motor torque in addition to the external force as information.

The bilateral control algorithm of the current master-slave manipulator is based on the position command from the master arm, as shown in FIG. Is input to obtain the output angle θ _l and position control of the slave arm is performed, and the position control loop is a major loop. On the other hand, the signal value of the detection sensor 105 is the difference between the signal generated by the torque T _l generated by receiving the external force and the signal generated by the torque T _m generated by the reaction force of the motor torque when the slave arm is position-controlled. It corresponds. The detection signal of the detection sensor 105 is fed back to the master side and used as a reaction force from the slave to the master.

D. Problems to be Solved by the Invention In the conventional bilateral control reaction force detection method shown in FIG. 6, when the slave is moved, motor torque is generated even when there is no external force. As a signal is sent to the master, the master side operator feels a reaction force and deteriorates operability. This phenomenon becomes remarkable when the slave is operated with acceleration.

In view of the above-mentioned conventional technique, the present invention provides a reaction force detection method for a bilateral master-slave manipulator in which a reaction force due to a motor torque does not return to the master.

E. Means for Solving the Problems In the present invention for solving the above problems, a drive motor is provided in the drive arm of the slave arm, and the stator of the drive motor is rotatably supported by the drive arm and the drive motor The output shaft is connected to the driven arm, and rotation of the stator is regulated by an elastic material so that the rotation angle of the stator is within a predetermined range around a certain position. In a bilateral master-slave manipulator equipped with a detection sensor for detecting the rotating pressure of the stator, the armature current I _a of the drive motor is added to the motor torque constant K _T.
And the distance R from the axis of the output shaft to the detection sensor Is added to the output signal of the detection sensor as an external force received from the outside by the slave, and this is returned as a reaction force to the master arm.

F. Example The method of the present invention will be described below. FIG. 1 is a block diagram showing a method of the present invention for controlling a bilateral master slave manipulator having the configuration shown in FIG. As shown in the figure, in this method, the armature current I _a , the motor torque constant K _T, and the distance R between the shaft core of the output shaft 100b (see FIG. 5) and the detection sensor are calculated. Multiply with and multiply Ask for. And this multiplication value To the detection value F _S of the detection sensor 105, Is returned to the master arm example. Detection value at this time So the added value Becomes That is, the added value F does not include the influence of the motor torque at all, and indicates only the true external force (= reaction force). That is, the multiplication value Is added to the detection value F _S of the detection sensor, Can be erased, which allows the true external force Is obtained, and the reaction force F is returned to the master side, whereby the operator on the master side feels only the true reaction force.

The position control loop is the same as the conventional method shown in FIG.

G. Effects of the Invention As described above, according to the present invention, the following effects are obtained.

(1) The external force that the slave arm of the bilateral master-slave manipulator receives from the outside can be accurately detected.

(2) The external force received by the slave arm can be accurately returned to the master as a reaction force.

(3) The bilateral sensitivity of the manipulator can be improved.

(4) Even if the slave is suddenly operated when there is no load, the reaction force applied to the operator disappears and the operability can be improved.

[Brief description of drawings]

FIG. 1 is a control block diagram showing the method of the present invention, FIG. 2 is a block diagram showing a manipulator, FIG. 3 is a block diagram showing an operating force detection device of the manipulator, and FIG. 4 is IV-IV of FIG.
FIG. 5 is a schematic configuration diagram showing an operating force detection device used in a bilateral master-slave manipulator, and FIG. 6 is a control block diagram showing conventional bilateral control. In the drawing, 100 is a DC motor, 100a is a stator, 100b is an output shaft, 101 is a drive arm, 102 is a reduction gear, 102a is a casing, 102b and 102c are reduction shafts, 103 is a driven arm, 104 is an elastic material, 105 Is a detection sensor, _Ia is an armature current, K _T is a motor torque constant, R is a distance, and F _S is a detection sensor output signal.

Claims (1)

[Claims] 1. A drive motor is provided in a drive arm of a slave arm, a stator of the drive motor is rotatably supported by the drive arm, an output shaft of the drive motor is connected to a driven arm, and the stator is further rotated. An elastic member regulates the rotation of the stator so that the corners fall within a predetermined range around a fixed position, and is provided between the elastic member and the stator and includes a detection sensor that detects the rotational pressure of the stator. In the lateral master-slave manipulator, the motor torque constant K _T is added to the armature current I _a of the drive motor.
And the distance R from the axis of the output shaft to the detection sensor , A value obtained by adding the output signal of the detection sensor to the slave as an external force received from the outside and returning this as a reaction force to the master arm. A reaction force detection method for a bilateral master-slave manipulator. .