JPS6219388A - Controller for manipulator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention provides the ability to carry out required work by remote control in environments that are difficult for humans to easily access, such as outside a space stage or a nuclear power plant or inside a nuclear reactor in a nuclear power plant. The present invention relates to a manipulator control device suitable for controlling a manipulator.

[Background of the invention]

An example of an attempt to make remote control of a conventional masker-slap type manipulator as easy as possible is given in Japanese Patent Application Laid-open No. 58-1.
There is one disclosed in No. 37575. In this example, the three-dimensional image of the slave manipulator and the master manipulator can be viewed simultaneously in the same size and superimposed.

However, if the size of the real image of the master manipulator and the virtual image of the slave manipulator that appears to the operator's vision differs even slightly, the relative deviation between the movement of the master manipulator and the movement of the slave manipulator will vary depending on the position, making observation and operation extremely difficult. The problem was that it was difficult.

Furthermore, if this effect is suppressed by placing the slave manipulator in front of the master manipulator, it would be difficult to make the manipulator make minute movements, partly because the image is small. . The cause of the difficulty in making minute movements is the power clutch, shield, etc. in the power transmission mechanism of the manipulator.
There is friction, and not enough visual information is provided.

Conventionally, in multi-joint arm type master-slave type manipulators, the length of the slave arm is usually at most twice that of the master arm, but if the slave arm is longer (for example, the length of the master arm is (several times), it becomes especially difficult to make minute movements.

This will be explained below with reference to FIG. Figure 2 (1
) indicates the master manipulator, which is installed in the control room. FIG. 2) shows a slave manipulator, which is fixed, for example, in the space-exposed part of a spacecraft.

In FIG. 2(a), the pace 11 of the master arm 1 is connected to a pedestal 10 fixed in the control chamber so as to be rotatable about a rotation axis 100m.

One end of the pace 11 of the master arm 1 is connected to the upper arm 13 so as to be rotatable about the rotation axis 101a of the shoulder joint 12. The upper arm 13 has an elbow joint 140 and an axis of rotation 102 m.
It is connected to the forearm 15 so as to be rotatable with respect to the forearm 15 . The forearm 15 has three rotational axes 103m and 10 of the wrist joint 16.
4a, the hand portion 17 is rotatable with respect to the tosa.
is connected to.

The above is the configuration of the master manipulator. Next, the slave manipulator also has a similar structure (joints and rotation axis). That is, in FIG. 2(b), the pace 21 of the slave arm 2 is rotatably connected to the pedestal 2o fixed to the outer space exposed part of the spacecraft about the rotation axis 100b, and Rotating shaft 101b
The upper arm 23 is rotatably connected to the upper arm 23. The upper arm 23 is rotatably connected to the forearm 25 about the rotation axis 102b of the elbow joint 24. The forearm 25 has rotating shafts 103b, 104b, 105bIc of the joints 26 between the wrists.
It is rotatably connected to the hand section 27.

The operator grasps the hand portion 17 of the master manipulator and changes the position of the hand portion 17, thereby rotating each joint of the master arm. Correspondingly, the master arm joint and the corresponding slave arm joint (e.g. shoulder joint 1
2 and 22, elbow joints 14 and 24, etc.), the slave arm is controlled so that the joint rotation angles of the joints (2 and 22, elbow joints 14 and 24, etc.) are equal to each other. changes position.

The arm length of the mask is typically about the same length or less than about twice the length of a human arm. This is because, in order for the operator to operate the master arm, unless the length of the master arm is longer than the above, it may become impossible to operate or the operator's posture will become extremely poor, resulting in poor operability. It is from.

Since the rotation angle of each joint of the slave arm is equal to the rotation angle of the corresponding joint of the master arm, the master hand section 17
The ratio between the movement amount Δ and the movement amount ΔL of the slave hand section is given by the following equation.

Δl/ΔL=l/L ・・・・・・・・・・・・・・・
...(1) However, 1. L is the distance from the rotation axis of the relevant joint of the master arm and slave arm to the hand section, and this length changes depending on the rotation of the joint.
−It shall not change.

The minimum value of ΔL needs to be less than or equal to the accuracy (for example, 1 m) required for work performed remotely by the slave arm. At this time, the positional resolution Δr required for the master arm is given by: The left side of equation (2) is equal to the required minimum resolution Δd of the joint angle of the master arm.

If the slave arm is several times longer than the master arm, the above Δ
If d is too small, it becomes difficult to realize minute movements.

[Object of the Invention] An object of the present invention is to provide a master-slave type manipulator in which the operator controls the position of the slave arm by operating the master arm, so that the operator can easily realize minute movements of the manipulator. An object of the present invention is to provide a control device for a manipulator.

[Summary of the invention]

The present invention provides a multi-joint arm type master-slave system in which the joint rotation angles of the slave arms are controlled to correspond to the joint rotation angles of the master arm operated by the operator, so that the movements of the former follow the movements of the latter. In the control device of the manipulator, the angular magnification is calculated based on the positional resolution required for the slave arm and the threshold value of the joint operation angle of the master arm for the operator, and the mask 7-m is installed according to the calculated angular magnification. The present invention is characterized in that it includes a device that changes the rotation angle magnification between the joints of the slave arm.

Figure 4 shows that when the master arm is approximately the same length as a human arm, the operator positions the slave arm 2 via the master arm within a certain angular error from point P as shown in Figure 3. The results obtained by experiment for the case where the positioning time T required for the positioning permissible angle Bll is varied are shown below. According to this experimental result, when the allowable angle B is about 1 degree or more, the value of the positioning time T only weakly depends on B, but when B is less than 1 degree, the positioning time T increases as B decreases. increases significantly. This is the value at which the angular resolution required for the master arm (this is called the threshold)
The following operations, that is, operations where the angular resolution is 1 degree or less in the above experimental example, are extremely difficult for the operator to maneuver, and therefore require a large amount of time for positioning. It also means that you are extremely fatigued.

This threshold value depends on the accuracy and structure of the master arm and slave arm mechanisms, and is not necessarily limited to an angle of 1 degree, but may vary depending on the joint axis.
It has been confirmed through experiments that the angle is in the range of 0.5 to 3 degrees.

According to the present invention, when an operator operates the master arm, the movement of the master arm is controlled so that the required resolution of the master arm determined by the task is always equal to or higher than a threshold value (approximately 1 degree in the above experimental example). By contracting and transmitting the information to the slave arm, positioning can be easily performed to the highest position resolution determined by the mechanism of the slave arm.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention, and shows a control circuit for one joint of a master arm and a slave arm. These control circuits are provided to independently control the angles of the corresponding joints of both the master and slave arms on a one-to-one basis as shown in FIG. Hereinafter, explanation will be given with reference to FIG. 1, taking as an example one joint axis of each arm of the mask and slave. However, circuits for other joint axes have similar configurations.

An arm 30& is fixed to one end of one joint shaft 31m of the master arm l. Further, an encoder 32& and a force sensor 44 are attached to the joint shaft 31&. On the other hand, the joint shaft 31b of the slave arm corresponding to the joint shaft 31aK of the master arm is coupled to the arm 30b.

The joint shaft 31b includes an encoder 32b1, a tachometer 33,
A motor 34 is connected. Encoder 32m and 3
2b is an incremental type 69, and its output signals are input to position capacitors 35m and 35b, respectively. The position kakuntas 35m and 35b output a master joint angle signal PM and a slave joint angle signal p, respectively. The mask joint angle signal PM is multiplied by 1 h via a multiplier 36 and then input to a subtracter 38 . The slave joint angle signal P8 is input to a subtracter 38. The subtracter 38 has a position error output 6-p.

Output s. The deviation output ε is input to the position/velocity converter 39, and is converted into a velocity target value vr1 proportional to this.

The speed target value τ1 is input to the changeover switch 43. On the other hand, the output f of the force sensor 44 is converted via a force/speed conversion circuit 45 into a speed target value V□ proportional to this. Speed target value Ya2. is input to the changeover switch 43. The outputs 11a of the switching switch and tach are input to the subtracter 40, and the outputs of the tachometer and switch are also input to the subtracter 40, giving vr-τ.

is input to the motor via the amplifier 37 as the output of the subtracter 40.

The output S1 of the switch 46 mounted on the arm 30a is input to the mode switch 41, which outputs the dirt signal g.

The dirt signal g is output from the position counter 35a and the changeover switch 4.
It is input as a dirt signal of 3.

The output ΔL of the key hand 48 (positional resolution of the slave manipulator required for the work) is input to the arithmetic circuit 47. The calculation circuit 47 calculates the following and outputs the magnification M.

Here, α is a coefficient determined by the characteristics of the mechanism, etc., and is usually selected from 1 to 2. Pon1 is the minimum joint angle resolution (i.e., the threshold value) of the master arm that can be easily positioned by the operator, and is 1 to 2 degrees according to the experimental results shown in 6D, m4.

The output M of the arithmetic circuit 47 is input to the multiplier 36 and the data rewriting circuit 42. The data rewriting circuit 42 receives the signal M.
In addition, a slave joint angle signal pH is input, and MP is output. The output MPs of the data rewriting circuit 42 is input to the position counter 35m together with the dirt signal g.

Next, the operation will be briefly explained.

Before starting work, the operator inputs into the key date 48 the positioning resolution ΔL of the slave manipulator required for the work. The arithmetic circuit 47 calculates the magnification M according to equation (3).
is calculated.

The control mode of the manipulator can be changed to the following three states (i), (ii),
(Divided into iiD.

(1) When the switch 46 is off, the f-) signal g is low, and the output τ1 of the J selector switch 43
The joints of the slave arm are controlled in speed according to the torque applied to the joints of the master arm. That is, the target speed value τ is proportional to the torque fm applied to the master arm detected by the force sensor 44, and 2 is the angular velocity τ of the joint of the slave arm. The speed is controlled so that they are equal. Therefore, in this case, if the operator continues to apply force to the master arm, the slave arm will move in that direction, and if the operator stops applying force, the slave arm will come to rest. It can operate as a so-called mask slave type Jm stick.

(ii) When switching switch 46 from off to on, the dirt signal changes from low to high. The magnification m of the multiplier 36 is m = M, and the multiplier 36 outputs PM/M. At the same time, the data rewriting circuit 42 outputs MP, and this value is written into the master position counter 35m.

(+ii) When the switch 46 is on, f-) The signal g is high, the output 1 of the changeover switch 43 becomes vrnijir1, and the magnification m of the multiplier 36 is m=M.

At this time, υ·ε I = Kr (vrl−τC) is calculated as ε==pw/MPs 17r1=. Here, K, , K are the speed and current gain, and K is the current command value. In this mode, the joints of the slave arm move by IA times the operating angle PM of the joints of the master arm. Therefore, minute movements are possible.

To provide a supplementary explanation here, the above mode (11) is an operating state only at the moment of switching from mode (1) to mode (iiD).The reason for providing this mode (11) is as follows.Immediately after switching The output ε of the subtractor 38 must be zero, because if ε is 0, the above element 32
The slave motor 3 is controlled so that ξ=0 by the position control system consisting of b, 35b, 38, 39.43, and 37°34.
4 rotates, and the mask position counter 30b does not come to rest at the position at the time of switching. On the other hand, at the moment of switching, the mask position counter 35
When rewritten with the value of a t-MP, the output of the master position counter 35m=MpH, the output of the multiplier 36=field, xma=P, and ε=p, -p,=.

It is possible to keep the slave arm stationary.

That is, the mode (11) is provided to make the slave arm stand still immediately after the switch 46 is turned from off to on.

Note that when the switch 46 is turned from on to off, the control system of the slave arm 30b is controlled by elements 44°45.43.4.
Since the speed control system consists of 0, 37.34, and 33.40, the signal from the master position counter 35m is unnecessary. Therefore, the state at the moment the switch 46 is turned from on to off is equal to the off state of the switch 46.

In this way, according to this embodiment, the operator can
By switching, coarse movement can be performed by the slave arm in response to force and speed, and fine movement can be performed by the slave arm in response to position.

FIG. 5 shows another embodiment of the present invention, which differs from FIG. 1 in the following points. That is, the force sensor 44, the changeover switch 43, and the force/velocity conversion circuit 45t are removed, and e-) the position counter 35m and the multiplier 36 are used as the circuits to which the signal g is to be input.

In FIG. 5, the magnification m of the multiplier 36 is m=β when the switch 46 is off, the dart signal g is low, and m=M when the switch 46 is on, the g is high. β is normally set to 1, but may be set to 1 or less in some cases. When the switch 46 changes from on to off, the f-) signal g changes from high to low, and at this time βP3 is written in the position counter 35m.

The operation of the embodiment shown in FIG. 5 differs from the operation of the embodiment shown in FIG. 1 only in the following points. That is, by turning the switch 46 on and off, the position counter 35 is turned on and off as described above.
After βP3 is written in m, g == PM /β−P.

The position control circuit is such that the control circuit calculates τr=υε I=Kx(mu−νC). At this time, the rotation angle of the joint shaft 31b of the slave arm is 1// times the operating angle of the joint shaft 31m of the master arm (usually β≦1).

According to this embodiment, a force sensor is not required and the circuit configuration is simple.

FIG. 6 shows still another embodiment of the present invention. This embodiment differs from the embodiment shown in FIG. 5 in the following points.

An operator behavior prediction circuit 50 replaces the keyboard 48 and switch 46. An average value circuit 511 and a positioning tolerance determining circuit 52 are provided. Output Δp1 of the behavior prediction circuit 50
(ΔP1 has the dimension (dir) of the (joint) angle.) is input to the average value circuit 51. The output ΔP of the average value circuit 51 is input to the permissible value determining circuit 52. The behavior prediction circuit 50 determines the required positioning roughness ΔP after the time t1+Δ from the four turns of the operator's previous positioning motion.
This is to predict l. The average value circuit 51 is a circuit that averages Δpt every nΔ, and its output ΔP is ΔP=
1・ΔPi. Here, n must be an integer of 2 or more,
Decide appropriately depending on the characteristics of the system and the quality of work. When ΔP is less than approximately 1 d@g, the positioning tolerance determination circuit 52 changes the signal S1 from on to off, corrects Mt so that the signal S1 changes from off to on, and then changes the signal S1 from off to on. This is a circuit that allows At this time, the output of the multiplier 36 does not become βPm when the signal S1 changes from on to off, but t of the multiplier m' before the signal S1 changes from on to off.
It will be retained. Next, when the signal S1 changes from off to on, control is performed so that the new magnification m='M. Through the above series of operations □, the mask positioning tolerance corresponding to the slave positioning error is always set to 1.
It becomes more than normal. Although the configuration of the behavior prediction circuit 50 is difficult to realize with current technology, it will be possible to realize it in the near future due to the analysis of human behavior and I-turns and progress in research on artificial intelligence.

According to this embodiment, the operator can operate the slave in the most convenient state without being conscious of the positioning tolerance of the slave, and the operability is much improved.

〔Effect of the invention〕

According to the present invention, even if the slave arm is longer than the master arm, the operator can easily make minute movements of the slave arm, and the time required for positioning is shorter than the conventional one.
It can be shortened to 72 to 1/4, greatly improving operability and reducing operator fatigue.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the invention! Lock diagram, 2nd
Figures (a), (b), and (b) are external views of the master manipulator and slave manipulator, respectively, Figure 3 is an external view for explaining the experiment, Figure 4 is a graph showing the experimental results, and Figure 5 is a graph showing the experimental results.
6 and 6 are block diagrams showing other embodiments of the present invention, respectively. 30a, b...Arm 31a, b...Joint axis 3
2a, b... Encoder 33... Tachometer 34... Motor 35.
... Position counter 36 ... Multiplier 38 ... Subtractor 39 ... Position speed converter 40 ... Subtractor 41 ... Mode switch 42 ... Data rewriting circuit 43 ... Changeover switch 44...Force sensor 45...Force/speed converter 46...Switch 47...Arithmetic circuit 48...Keyboard L, -. Figure 2

Claims (1)

[Claims] A control device for a multi-joint arm type master-slave manipulator that controls the joint rotation angles of slave arms to correspond to the joint rotation angles of a master arm operated by an operator, so that the movements of the former follow the movements of the latter. , a device for calculating an angular magnification based on the positional resolution required for the slave arm and a threshold value of the joint operation angle of the master arm for the operator; A control device for a manipulator, comprising a device for changing the rotation angle magnification between the joints of the manipulator.