JPS5810209A - Control system for master-slave manipulator - Google Patents

Abstract

PURPOSE:To freely operate a master arm without shifting the position of both arms, by adding an electric signal corresponding to a stored torque to a deviation signal of a joint angle. CONSTITUTION:An electric signal Es representing a torque generated from a driver 5 of a master arm 1 is stored in a memory 110. This electric signal Es is added to a deviation signal E at an adder 113 and inputted to a driver 6 via an amplifier 8. Thus, the driver 6 can be activated so that joint angles thetaM and thetaS can be made equal without shifting the master arm 1 and a slave arm 2 relatively. On the other hand, a system consisting of a speed detector 101, a dead band element device 102, a torque detector 104, a signal converter 106, a switching element device 107, a memory 109, a signal converter 11 and an adder 112 can realize further improvement of the sense of operation by the operator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a master-slave type manipulator control system, which is improved so that work can be performed reliably with good maneuverability when a remote slave arm is operated by controlling the master arm. It is.

For example, when a robot is used to perform light work that humans would do using general-purpose tools, such as opening and closing valves or increasing the number of bolts, inside the containment vessel of a nuclear power plant, a robot with a slave arm is placed inside the containment vessel. A method has been adopted in which a human (operator) remotely controls the slave arm by operating the master arm outside the container.

A conventional example of such a master-slave type manipulator control system will be described with reference to FIG. An example of this is a feedback control system called a symmetric type (also called pi-bi-chiral servo). In the figure, l is the master arm and 2 is the slave arm, which is the wrist and elbow, respectively.

It is a multi-jointed arm having shoulder rotation or torsion joints, and both arms 1.2 are electrically coupled as follows. That is, the joint angle θM of the master arm 1 operated by the operator (worker) is converted into an electric signal by the position detector 3, and on the other hand, the joint angle 0 of the slave arm 2 is also converted into an electric signal by the position detector 4. Sanru.

Electrical signals from both position detectors 3 and 4 become differential inputs of a comparator 9, and its output is a deviation signal ΔE−〇M−θB
is applied to the drive device 6 on the slave arm side via the amplifier 8. This drive device 6 drives the slave arm 2 so that θS matches θM. ′! Comparator 9
The output ΔE is converted into -ΔE by the sign inverter 10, and then sent to the drive device 5 on the master arm side via the amplifier 7.
given to. This drive device 5 acts on the master arm 1 to make θM match θS, and gives the operator of the master arm 1 a reaction force corresponding to the torque in the direction of making θM match θS.

By symmetrically providing the tab and position servo systems,
The operator feels the force acting on the slave arm 2 or the torque it holds as a force sensation,
The aim is to achieve more reliable maneuvering.

However, the prior art shown in FIG. 1 and described above has the following drawbacks. That is, ■ slave arm 2
When a load torque is applied, such as when carrying a heavy object, the output ΔKi of the comparator 9 has to be increased in order to maintain this load torque, and the positional deviation between θM and 0 days increases.

In other words, in order for the operator to feel the force, the master arm must be
It is necessary to operate with the position θM of the slave 7-2LD and the position θS of the slave 7-2LD relative to each other, and the maneuverability is deteriorated accordingly.

■ When the load torque disappears, such as when a heavy object is released,
The drive device 6 moves the slave arm 2 in the direction of decreasing the positional deviation, that is, ΔE, and the master arm 1
Slave arm 2 makes unnecessary movements even though it is stationary.

■ After that, until day 0 coincides with θM, a torque proportional to the positional deviation -ΔE acts on master arm 1, and the operator continues to feel a reaction force even though there is no load torque. There is a great sense of discomfort.

In view of the above-mentioned drawbacks of the prior art, the present invention provides a control system that allows the master arm to be operated without shifting the positions of both the mask and slave arms, regardless of the load, and allows the work to be performed more reliably. It is something to do. Therefore, in the configuration of the present invention, in a master-slave type manipulator, the torque generated by the drive device that drives the master arm is detected and converted into an electric signal, and when the speed of the joint angle of the slave arm is in a predetermined low speed range. The electric signal is stored in the apparatus, and the stored electric signal is added to a joint angle deviation signal between the master arm and the slave arm. The present invention will be explained below based on FIG.

In FIG. 2, parts that perform the same functions as those in FIG. 1 are given the same reference numerals to avoid redundant explanation.

FIG. 2 is a block diagram of an embodiment of the present invention. In the figure, reference numeral 101 is a joint angle speed detector, which converts the joint angle speed 9 from the joint angle of the slave arm 2 into an electrical signal and outputs it. 102 is a dead zone element device such as a comparator, and in this example, the joint angular velocity 2 of the slave arm 2
．． It is assumed that a low level signal, that is, an L signal is output when the speed is in a predetermined low speed range, and a high level signal, that is, an H signal is output at other times. Reference numerals 103 and 104 are torque detectors, which detect the torque that is effectively acting on each arm out of the torque generated by the drive devices 5 and 6 of the master arm 1 and slave arm 2, respectively, and convert this torque into an electrical signal. Convert to signal and output. For torque detection, for example, when a DC torque motor is used in the drive device 5.6, its armature current may be detected and converted into torque. 105 and 106
are signal converters, and torque detectors 103 and 1, respectively.
The output signal from 04 is subjected to a predetermined signal conversion process and output. 107 and 1013 are switch element devices that operate with the signal from the dead zone element device 102, and when the L signal is input, the signals 1! ! 9. InM each memory 109
゜110, and when the ■ signal is input, it does not output anything and does not transmit it to the memory. 111 is a signal converter)
, the output signal 1 from the memory 109 storing the torque signal % on the slave arm side! ! y is converted into a predetermined signal 4 and output. 112 and 113 are adders, and one adder 112 is a signal converter 11 for the deviation signal ΔE from the comparator 9 and the torque signal KM on the slave arm side.
The other adder 113 adds the deviation signal ΔE from the comparator 9 and the master arm side torque signal EB from the memory 110 and outputs it to the sign inverter 10. Output to amplifier 8.

Speed detector 101 in FIG. Dead zone element equipment 1
02. ) Lux detector 103. Signal converter 105. Switch element device 108. A system consisting of the memory 110 and the adder 113 realizes the present invention, and the slave arm 2
An electrical signal mB representing the torque generated by the drive device 5 of the master arm 1 is stored in the memory 110 under the condition that the joint angular velocity θS of the master arm 1 is in a predetermined low speed range. The stored electric signal Es is converted into a deviation signal Δ by an adder 113.
The drive device 6 adjusts the joint angles θM and θB of each arm without relatively shifting the master arm 1 and the slave arm 2 by inputting it to the drive device 6 via the amplifier 8. It works. On the other hand, the speed detector 1011 dead zone accumulator 102. Torque detector 104. Signal converter 106. Switch element device 107.
Memo 1J109. The system consisting of the signal converter 111 and the adder 112 realizes further improvement of the operator's sense of control.

In other words, under the same speed conditions as above, slave arm 2
An electrical signal PM representing the torque generated by the drive device 6 is stored in the memory 109. The level of the stored electric signal EM is adjusted by the signal converter 111, and the signal gl is added to the deviation signal ΔE by the adder 112, and the signal gl is added to the deviation signal ΔE by the sign inverter 1.
0 and the drive device 5 via the amplifier 7, the drive device 5 controls the master arm so as to give the operator an appropriate amount of reaction force proportional to the force acting on the slave arm 2 or the torque held by the slave arm 2. 1.

A specific example of operation will be described below.

[Operation Example 1] The operation in a state where the Nislepe arm 2 is not acting on the target object will be described.

When the operator manipulates the master arm 1, its joint angle θM changes. (K) A deviation signal ΔE is generated, and the slave arm 2 starts moving so that ΔE becomes zero.

As a result of this operation, θS approaches θM and enters the low speed range where 8 is reached, the slave arm side receives an electrical signal 1! corresponding to the torque detected by the torque detector 103 of master arm l. Since lS is added to the deviation signal ΔE, the slave arm 2 is moved by its drive 6 until 3m + EB-it is zero. On the other hand, on the master arm side, an electric signal proportional to the torque detected by the torque detector 104 of the slave arm 2 is added to the deviation signal ΔE. A reaction force is applied to the drive device 5 via the master arm l. In this way, the slave arm 2 is moved, and finally Δm=o.

B8=O, gXl=o and stops.

This allows for reliable operation under no load by operating in the same manner as before.

[Operation fli2] The operation when causing the Nislepe arm 2 to act on the target object will be described.

By the operator manipulating the master arm l, θM
When ΔE changes, the individual difference signal ΔE increases and the slave arm 2 tries to move in the direction that makes Δ1B zero, but since the slave arm 2 is acting on the target object, its joint angle θS hardly changes. Without this, the joint angular velocity as naturally falls into the low velocity range.

Therefore, the slave arm 2 is pushed by the driving device M6 in the direction in which Δg+gB becomes zero.

Further, a reaction force is applied to the operator by the drive device 5 via the master arm 2 so that ΔE+w4 becomes zero. In this case, since the electric signals FB and VL corresponding to the torques of the respective drive devices 5.6 acting on the master arm 1 and slave arm 2 are added to the deviation signal ΔE, θM and #day match and Δ11C=O Even if
The pressing force of the slave arm 2 and the reaction force of the master arm 1 are each maintained. Incidentally, the reaction force can be reduced to a value that provides good maneuverability by adjusting the E forest level using the signal converter 111.

Both arms, mask and slave 1. 2. A torque proportional to the steering torque can be applied to the target object without causing a positional deviation ΔE, and reliable maneuvering can be performed with good maneuverability.

Cut example 3] We will describe the operation when a load such as a tool is applied to the Nislepe arm 2, such as a workpiece.

First, the operation according to the conventional method will be described. When the operator manipulates the master arm 1 to make the sub-arm 2 hold the hammer, the load torque to maintain the 1 mm is controlled only by the deviation signal ΔE. Since the drive device 6 had to generate the joint angle of the master arm l, in order to keep the slave arm 2 stationary with -
The relationship of θB+ΔE must be maintained, and the joint angles of both arms cannot match.

In contrast, in the present invention, the joint angular velocity JB is in a low speed range when the body is held stationary, so the deviation signal Δ
EKT! , the drive device 6 starts operating, and the load torque of the hammer is adjusted based on wB.
occurs (- and gives this to slave arm 2 to hold the hammer. Therefore, by shifting master arm 1, ΔP
Since the steering torque corresponding to Fis continues to be generated without -i occurring, the operator can keep the slave arm 2 holding the hammer stationary in the state of θM-θ8. At the same time, since the force is added to the control of the drive device 5, the operator can feel an appropriate amount of hammer holding reaction force under the condition θM=−θ.

Next, when the slave arm 2 is moved out of the low speed range with a joint angular velocity of 0 days while holding the hammer, the torque for holding the hammer is stored in the memory 110 by - just before exiting the low speed range. Since the deviation signal ΔE generates a torque for movement, the slave arm 2 reliably matches the movement of the master arm 1 (θs=θM).

Therefore, the hammer-holding torque generated and applied to the slave arm 2 acts to move the slave arm 2f by ΔE+ while the hammer is released [14]. However, as mentioned above, master arm 1 and slave arm 2 are at almost the same position (θM - θB), so comparator 9 is generated in drive device 6 - ΔEl is input, and slave arm 2 is at the same position as master arm l. Immediately settle in the same position as Moreover, the reaction force of the hammer 1l-1dl' hammer holding force of the slave arm 2 immediately disappears from the master arm 1, resulting in a stable force sensation for the operator. In addition, in the conventional method, to explain the operation when releasing the -.mamma, both the mask and slave arms 1.
2 has already shifted by an amount equivalent to ΔE, and if you release the arm in this state, ΔE - ΔE1 will become slave arm 2.
Since this was applied to the drive device 6 as an input for movement, the slave arm 2 at that moment jumped up and operated unstablely.

Furthermore, even when the hammer is released, the reaction force remains attenuated and does not disappear immediately until the already shifted position is the same, giving the operator an unstable sense of force.

In other words, even when a load is applied to the slave arm 2, the positional deviation ΔE of both the mask and slave arms 1.2 can be made zero, and the slave arm 2 can be held still while being felt by the torque controller operator in proportion to the load. This allows for good maneuverability and reliable operation.

As explained above, in the conventional method, if there was a load, the positional deviation of both the mask and slave arms did not become zero, and the positional deviation depended on the degree of load, impairing maneuverability. According to the invention, the positional deviation becomes zero at #t regardless of the load, and the difference in load has almost no effect on maneuverability, allowing reliable A maneuver with good maneuverability.

I would like to add here that some examples of equipment to which the present invention is applied include manipulators for work that handles hazardous materials such as radiation, explosives, and harmful substances, and manipulators that work in adverse atmospheres such as radiation and harmful gases. There are manipulators for working in the water, manipulators for working underwater, under the sea, etc., manipulators for working in space, etc.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a conventional technique, and FIG. 2 is a block diagram showing an embodiment of the present invention. In the drawing, l is a master arm, 2 is a slave arm, 3 and 4 are position detectors, 5 and 6 are drive devices, 9 is a comparator, 10 is a sign inverter, 101 is a speed detector, and 102 is a dead band element device,
103 and 104 are torque detectors, 105 and 106 are signal converters, 107 and 108 are switch element devices, 109 and 110 are memories, 111 is a signal converter, 112 and 113
is an adder, θV is the joint angle of the master arm, θ8 is the joint angle of the slave arm, θ is the velocity of the slave arm joint angle, ΔE is the deviation signal, E8 is the electrical signal of the stored torque on the master arm side, EM is the stored electrical signal of the slave arm side torque, and "M" is the electrical signal converted into the FM signal. Patent applicant: Mitsubishi Heavy Industries, Ltd. Sub-Attorney Yf! Shibu Tokoishi (and one other person)

Claims (1)

[Claims] In a master-slave type manipulator, the torque generated by the drive device that drives the master arm is detected and converted into an electrical signal, and the electrical signal is stored when the speed of the joint angle of the slave arm is in a predetermined low speed range. A master-slave manipulator ill control method characterized in that the stored electric signal is added to a joint angle deviation signal between the master arm and the slave arm.