JPH01257579A - Manipulator - Google Patents

Abstract

PURPOSE:To conduct rough teaching operation by a master or the like surely and easily by providing a control device for feedbacking a detection signal showing the relation between an object of work and an end effector to portions other than a portion for regulating the position attitude of a slave manipulator in a work breakdown teaching device. CONSTITUTION:A slave regulates rough position and attitude of an end effector by teacing means such as a master or the like. The position and attitude of the end effector for an object of work at this time is detected by a detection sensor 2. An output signal of the detection sensor 2 is feedbacked to portions other than a portion for regulating the position and attitude of a slave manipulator in a work breakdown teaching device such as a master or the like. Thus, the assisting degree of freedom of the slave manipulator is controlled to always keep the position and attitude of the end effector for an object of work constant. Accordingly, even if the teaching contents for the slave are rough, teaching operation can be accomplished surely and easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a manipulator, and particularly to a manipulator suitable for working while maintaining a certain constraint relationship between a work object and an end effector.

[Conventional technology]

With a master-slave type manipulator, it is difficult to perform work that involves restraint operations that keep the end effector's position and posture constant using master-slave control alone.

Furthermore, even with a long manipulator, it is difficult to maintain a constant relationship between the end effector and the workpiece due to dynamic deflection of the long manipulator, bank lash of the joint-driven deceleration mechanism, and the like.

1) The conventional technology for 1j operators detects the relationship between the work target and the end effector, and uses the output to generate compliance in the arm joint of the master manipulator that defines the position and posture of the slave. There is a method in which the operator detects the relationship between the work object and the end effector.

With long manipulators, when teaching work movements, T
The tip of the manipulator was monitored using a V-camera, etc., and the teaching contents were corrected through trial and error before the actual work began.

[Problem to be solved by the invention]

In the conventional technology for master-slave type, the operator is required to always feel the reaction force transmitted to the mask and delicately manipulate the many degrees of freedom of the mask that define the position and orientation of the slave so that the reaction force disappears. Therefore, there is a problem in that operator fatigue increases.

The latter long manipulator takes time to teach and increases teacher fatigue.

Therefore, an object of the present invention is to provide a means for reliably and easily realizing the work even with rough teaching using a mask or the like.

[Means to solve the problem]

The above purpose is to provide a detection sensor that detects the relationship between the work object and the end effector, a slave that executes the work, a work content teaching device, and a work content teaching device such as a master that uses the output of the detection sensor and the slave of the slave. This is achieved by configuring a control device that provides feedback to parts other than those that define the position and orientation.

(Operation) The slave defines the approximate position and orientation of the end effector using a teaching means, such as a mask.The detection sensor detects the position and orientation of the end effector at this time with respect to the work object.The position and orientation of the slave The slave has degrees of freedom (this is called the auxiliary degree of freedom) other than the degree of freedom (this is called the main degree of freedom) for controlling the position and orientation of the slave, and the mask has the end effector operation. Taking the slave's auxiliary degree of freedom as an example, the slave's auxiliary degree of freedom is controlled by the control device so that the position and orientation of the end effector relative to the work object are kept constant by the detection sensor. As a result, even if the instructions given to the slaves are rough, the work can be accomplished reliably and easily.In particular, with master-slave control, mask operation is easier and operator fatigue is reduced. Become.

〔Example〕

Embodiments of the present invention will be described below by taking a plasma cutting operation as an example.

As a first embodiment, a case where an auxiliary degree of freedom is provided in an end effector will be described using FIGS. 1 to 5. 1st
In the figure, slave 8 includes arm 81 end effector 1,
It is composed of a detection sensor 2 and a plasma torch 3. The arm 81 is composed of six main degrees of freedom so that the position and posture of the end effector 1 can be defined. FIG. 2 shows an embodiment of the end effector 1 and the detection sensor 2. As shown in FIG.

FIG. 3 is an explanatory diagram of detection of the posture of the end effector 1 with respect to the work object 9 by the detection sensor 2. The detection sensor is
Ring-shaped detection sensor plate and detection sensor plate 2
Distance sensors 2u and 2a attached to the top, bottom, left and right of 1
, 2 and y 2R.

The suffixes u, d, L, and R indicate that the distance sensor is mounted in the upper, lower, left, and right positions, respectively. Distance sensor 2u
, SL, 2R12L are the distances to the work object 9, respectively.
Detect u, Qar QRl and Q, L.

The end effector 1 includes a telescoping shaft 11 that moves the plasma torch back and forth with respect to the arm 81, a left-right travel shaft 12 that rotates the plasma torch left and right, and a vertical travel shaft 1 that rotates the plasma torch vertically.
Has 3. The telescopic shaft 11 includes a motor 111 and an encoder 1.
12 and a ball screw 113. The plasma torch 3 is fixed to a plasma torch holder 14 and moved back and forth by a ball screw 113. The detection sensor 2 also
It is fixed to the plasma torch holding part via the detection sensor guide 22, and is attached to the ball screw 11 along with the plasma torch.
3 moves forward or backward. The left-right travel axis 12 is composed of a motor 121, an encoder 122, a bearing 123, and a shaft 124. By driving the motor 121, the entire end effector 1 is turned left and right by the shaft 124 fixed to the rotor of the motor 121. do.

The vertical travel rotation shaft 13 is also configured in the same manner as the left and right travel rotation shaft 12, and rotates the entire end effector 1 up and down.

Next, a method of controlling the auxiliary degrees of freedom in the end effector 1 using the detection sensor 2 will be described. Figure 4 shows
A block diagram of the control device 6 is shown, showing the case where the telescopic shaft 11 is controlled. The control device 6 includes a command value calculation section 61 for each axis based on the output Q of the detection sensor 2, a control element 62 that determines the amount of operation to perform desired control based on the command value, and a motor driver 63. FIG. 5 shows the control algorithm in the command calculation section. In plasma cutting.

It is desirable to keep the distance between the plasma torch 3 and the workpiece 9 (this is called a standoff) constant and to keep the attitude of the plasma torch 3 perpendicular to the workpiece 9. To keep the standoff constant, calculate the average value of the four distance sensors (sequence 10, hereafter sequence is abbreviated as S) and compare it with the desired standoff Lo, which is 520.
), the telescopic shaft 11 is controlled based on the difference (S30, 5
40).

If the control element 62 is composed of a nonlinear element having a dead zone as shown in FIG. 4, the telescopic shaft 11 will be controlled in an on-off manner. In addition, in order to keep the posture of the plasma torch constant, the left and right distance sensors QL + Qn are set comparatively at 55
0), and the left and right travel axis 12 is controlled based on the difference (S60.
70) Similarly, the upstream and downstream rotations 13 are controlled using L, the vertical distance QL, and OR (S80, 90, 100). This control is repeated until the work is completed. FIG. 6 shows the process when one of the four distance sensors cannot detect the distance to the work object at the end of the work object 9, and the upper distance sensor Q
The case of u is shown. It is defined that the work object 9 cannot be detected when the value Qu of the distance sensor exceeds a certain value (Q uu). The standoff α is the left and right distance sensor 21. ,
Even with the average value of 2R, the vertical distance sensor 2. ．． 2. Since it can also be found by the average value of
10) The processing of the telescopic shaft 11 and left and right rotation is the same as in FIG. 4 (S220). Upstream and downstream rotations are controlled in the same way as shown in Fig. 4 by comparing this standoff L and the lower distance sensor Q- (S250°260.2
70). In this way, the auxiliary degrees of freedom in the detection sensor 2 and the end effector 1 allow the relationship between the work object and the plasma torch 3 to be maintained in the desired state even if the position and orientation of the end effector 1 are roughly taught. can be done reliably and easily.

Next, as a second embodiment, a case where the auxiliary degree of freedom is disposed within the arm and the auxiliary degree of freedom also serves as the main degree of freedom will be described with reference to FIGS. 7 to 9. FIG. 8 shows an example of the degree of freedom arrangement of the manipulator 8 to which the present invention is applied. The zero manipulator 8 has a roll θ1. pitch θ2
．． Pitch 03. Roll θ number, pitch θ6 and roll θG
It has a degree of freedom arrangement, and an end effector 5 shown in FIG. 8 is attached to the tip. The manipulator 8 has θ+, O
z.

The position of the end effector is defined by the three axes on the root side of θ3, θ number, θ5. The attitude of the end effector 5 is determined by the three axes on the tip side of θB. The end effector 5 is fixed to the tip of the θB axis. The end effector 4 shown in FIG. 8 is composed of a plasma torch 3, a plasma torch holding section 41, and a contact type detection sensor 5. The contact type detection sensor 5 is a second embodiment of the detection sensor, and the distance from the work object 9 is Qul Qa+ QL+
Contact type distance sensors 5u+ 5d+ 5Ll 5R are used to detect QR (subscript content is the same as detection sensor 2). Contact type distance sensor5. ．． 5=, 5L,
5R has a mechanism that constantly presses the sliding rod 52 against the work object 9 using a spring 51, and a tip is provided at the tip of the sliding rod 52 so that the sliding rod 52 can smoothly slide over the work object 9. Pole casters 53 are attached.

The distance Q is detected by the position of the sliding rod 52 with respect to the guide 54. In the contact type detection sensor 5, the standoff is the spring 5
1 is automatically corrected. Therefore, in the present invention, what must be actively controlled is the attitude of the end effector. The degrees of freedom of the manipulator for efficiently correcting this posture are the left and right travel axis of the θ4 axis and the vertical travel axis of the 05 axis.

Next, a method of controlling the 04 and 05 axes will be explained. FIG. 9 shows a block diagram of a control device in this embodiment. The basic configuration of the control device 6 is the same as that of the first embodiment, but the configuration of the command section calculation section 61 is slightly different. The command unit calculation unit 61 includes a target value change unit 611 that calculates a target value change amount based on the outputs Q and QR of the detection sensor 5, and a target value calculation unit 611 that calculates the target value. Target value change unit 611
The processing content corresponds to the left/right and up/down travel of the control algorithm of the first embodiment shown in FIGS. 5 and 6. For example, the posture correction 1tRc4 for correcting the left and right postures of the end effector using the θ4 axis is determined by the following equation.

RC4=K CQR12r)
-(1) where: constant Further, the target value calculation unit 611 calculates the amount of operation signal by calculation of equation (2).

Q+= (P114+RC4) Ps4
-(2) Here, P: Master position signal Ps Nislepe position signal Subscript 4: The θδ axis indicating the 04 axis is similarly determined. As shown in equation (2), the feature of the control of this embodiment is that in the slave control system of the conventional master-slave control (portion 7 within the broken line in FIG. 9),
The objective is to adopt a control strategy in which the posture correction amount determined by the detection sensor 5 is superimposed on the mask position signal Ps, which is the target value. By controlling in this manner, the posture of the end effector 4 can be automatically maintained in a desired state simply by roughly specifying the position of the slave using a mask. Therefore, the operator is not burdened with the burden of operating while paying attention to subtle reaction forces as in the conventional case, so there is less fatigue, and the operation is simple and easy.
Can be operated reliably.

Finally, a third embodiment will be described using FIGS. 10 and 11. The third embodiment is a method in which the amount of posture correction determined by the detection sensor is fed back as a reaction force to the end effector operating device of the mask instead of the auxiliary degree of freedom of the slave. In this embodiment, a case will be considered in which the standoff scale of the plasma torch 3 is used as the attitude correction amount.

In the first and second embodiments, the standoff scale is the telescopic shaft of the end effector 1 or the contact distance sensor 5u.
It can be adjusted to some extent by the 5R spring 51. However, there may be cases where the adjustment range of both is exceeded. To deal with this, it is better to provide feedback to the operator as to whether or not the standoff scale is within the allowable range in order to improve operability. In this case, if feedback is given to the degree of freedom that defines the position and orientation of the slave among the degrees of freedom of the mask, this will cause a disturbance to the position and orientation of the slave, which is undesirable for operation. Therefore, it is fed back as a reaction force to the end effector operating device of the mask, which is unrelated to the position and orientation of the slave.

FIG. 10 shows one embodiment of a master gripper 10 that includes an end effector manipulator 101. As shown in FIG. The operator grips the gripper 103 and presses the end effector operating device 10 with his or her index finger.
Operate part 1. By applying torque to the motor 102, the operator can feel a reaction force. 104
is a torque detector. FIG. 11 shows a block diagram of the control device 20 in this embodiment. The basic configuration of the control device is the same as in the second embodiment. The difference is that while the second embodiment feeds back the position Ps of the slave, the present embodiment feeds back the reaction force f of the gripper of the mask.

In the torque command unit 211, the torque T generated by the motor 102 is as follows: T=R(1, -L O) -
(3) Therefore, the target value calculation unit 213 calculates a target value to be given to the gripper torque control system of the conventional mask, which is indicated by the broken line 30. Therefore, according to this embodiment, the work can be reliably accomplished without separating the end effector 2 or 4 from the work object.

〔Effect of the invention〕

According to the present invention, a work can be reliably and easily realized even by rough teaching from a work content teaching device such as a master.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the present invention in which the end effector has an auxiliary degree of freedom, and FIG. 2 is a sectional view of the end effector and detection sensor of FIG. 1. Fig. 3 is a perspective view showing the relationship between the detection sensor and the work object, Fig. 4 is a block diagram of the control device, Fig. 5 is a normal control algorithm diagram of the command calculation section, and Fig. 6 is the end FIG. 7 is a diagram of the control algorithm of the command calculation unit when the effector comes to the end of the workpiece, FIG. 7 is a diagram showing a configuration example of a slave manipulator applied to the second embodiment of the present invention, and FIG. 9 is a block diagram of the control device of the second embodiment, and FIG. 10 is a block diagram of the mask gripper used in the third embodiment. The figure shown in FIG. 11 is a block diagram of the control device of the third embodiment. 2...Detection sensor, 2u~2R...Distance sensor, 3
...Plasma torch, 5...Contact detection sensor, 6
...Control device, 8...Slave manipulator, 9
...Work pair Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 8 (θ6) Figure 9 Figure 10

Claims (1)

[Scope of Claims] 1. Consisting of a sensor for detecting the relationship between the work object and the end effector, a slave manipulator that executes the work, and a work content teaching device, the output of the detection sensor is transmitted to the slave manipulator of the work content teaching device. A manipulator comprising a control device that provides feedback to parts other than regulating the position and orientation of the manipulator. 2. The manipulator according to claim 1, wherein the slave manipulator is configured with a main degree of freedom that defines the position and orientation and other auxiliary degrees of freedom, and the output of the detection sensor is fed back to the auxiliary degree of freedom. A manipulator comprising a control device. 3. The manipulator according to claim 2, wherein the end effector has an auxiliary degree of freedom. 4. The manipulator according to claim 2, characterized in that the auxiliary degree of freedom also serves as the main degree of freedom. 5. The manipulator according to claims 1 to 4, wherein the work content teaching device is a master manipulator. 6. The manipulator according to claim 5, further comprising a control device that feeds back the output of the detection sensor to the degree of freedom for controlling the end effector of the master manipulator.