JPS63169281A - Pushing-force control system of robot - 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] [Summary] A pressing force control method for a robot hand having a force sensor, in which a mechanical means having a resolution finer than that of the robot is used as a pressing base, in order to obtain a pressing force that is less than the resolution of the robot. By configuring the device so that the pressing force of the hand is finely adjusted by controlling the position of the mechanical means, it becomes possible to easily obtain a pressing force that is less than the resolution of the robot.

[Industrial application field]

The present invention relates to a pressing force control method for a robot hand having a force sensor.

For example, when a robot inserts and fixes a tube or the like into a stopper, a certain amount of pressing force is required.

During this operation, for example, if the stopper is very thin and the robot inserts it with strong pressing force, there is a risk that the stopper may be crushed.

Therefore, a method has been adopted in which a force sensor is provided in the robot hand and the strong pressing force is controlled using this sensor.

However, if adjustment is required that is less than the resolution accuracy that can be obtained by the robot, the pressing operation cannot be appropriately controlled with the target pressing force.

It is desired that the robot in such a case be able to control the force so that it can perform the pressing operation with an optimal force.

[Conventional technology]

FIG. 3 shows block diagrams explaining the conventional example.

The block diagram shown in FIG. 3 includes a control device 1 that controls the operation of the robot 2, a robot 2 that performs various tasks under the control of the control device 1, a hand 3 that performs various tasks of the robot 2, and a hand 3 that performs various tasks.
and a support table 5 that supports the stopper (b) and receives the pressing force of the hand 3 when inserting the tube (a) into the stopper fb). has been done.

The control device 1 also includes an arithmetic processing unit 6 consisting of three registers 61 to 63, two arithmetic units 64 and 65, and arithmetic units 81.
Amplifier 82. Motor 83. The robot control unit 8 includes an encoder 84 and a force/position converter 7 that converts force into position and feeds it back to a position command.

Note that the register 61 indicates the movement start position X of the tube (a),
The register 62 is a movement amount register that sets the movement amount ΔX of the tube (a).
The register 63 is a register that sets the target pressing force F of the hand 3.

Further, the calculator 64 calculates the contents of the start position register 61 and the movement amount register 62 and sends out (X, +ΔX), and the calculator 65 calculates the force f0 detected by the force sensor 4 and the target pressing method F. and sends (ro-F).

A computing unit 81 in the robot control unit 8 computes the output (X, +ΔX) of the computing unit 64 and the output of the encoder 84, and the motor 83 serves as a drive source for the robot 2.

Further, the encoder 84 converts the rotation speed of the motor 83 and outputs a predetermined signal, and the force/position converter 7 converts the output of the calculator 65 into the movement position of the robot 2.

Normally, the resolution of the robot 2 is about 0.1 mm, and the pressing operation by the robot 2 is performed within this resolution range.

That is, when the robot 2 performs the work of pressing and inserting the tube (al) into the stopper (b) installed on the support table 5 as shown in FIG. , are preset in the start position register 61, and the target pressing method F is preset in the register 63.

Next, as the robot hand 3 starts moving, the amount of movement ΔX is sequentially set in the movement amount register 62, and by applying a driving force corresponding to the amount of movement ΔX to the motor 83, the robot hand 3 moves to a certain position. Using pressing force, move the tube (a) to the stop (b) at position X.

The pressing force when the robot hand 3 is moved by the amount of movement ΔX is calculated by calculating the detection signal of the force sensor 4 installed in the robot hand 3 with the contents of the register 63, and transmitting the result (fo-F) to the robot control unit 8. It can be obtained by

That is, by eliminating the displacement proportional to the generated force f0 from the target value F set in the register 63 and feeding it back to the computing unit 81 via the force/position converter 7, the force of the robot hand 3 is reduced. Take control.

[Problem that the invention seeks to solve]

However, as mentioned above, in proportion to the force f0 generated in the force sensor 4 of the robot hand 3, the tube (a) is
The pressing force control for each step of pressing on b) cannot be controlled below the resolution of the robot 2.

Therefore, for example, unless the pressing force is delicately controlled, it is impossible to perform an operation that may crush the stopper when inserting the tube (a) into the stopper thread by pressing it.

[Means for solving problems]

FIG. 1 shows a block diagram illustrating the invention in detail.

The principle block diagram of the present invention shown in FIG. 1 includes functional blocks 2 to 4 explained in FIG. A control device comprising a robot control JB section 80 that controls the pressing force of the Motozuki robot 2 and a control means (support table control section) 90 that controls the drive of the support table 50. 10, and after the control of the control device 10, in the same direction as the robot 2,
The robot 2 is configured to include a mechanism means (support table) 50 that moves with a resolution lower than that of the robot 2.

[Effect]

A mechanism means (support table) 50 having a finer resolution than the robot 2 is used as a pressing base, and the pressing force of the robot hand 3 is finely adjusted by controlling the position of the mechanism means (support table) 50 that moves in the same direction as the robot 2. By configuring this, it becomes possible to easily obtain a pressing force that is less than the resolution of the robot 2 using a simple method.

〔Example〕

The gist of the present invention will be specifically explained below with reference to an embodiment shown in FIG.

FIG. 2 shows a block diagram illustrating the invention in detail. Note that the same reference numerals indicate the same objects throughout the figures.

The control device 10 of this embodiment that controls the robot 2 has a third
A movement amount register 71 that sets the movement amount of the support table 50 in the functional block of the arithmetic processing unit 6 explained in the figure, a movement start position register 72 that sets the movement start position of the support table 50, and an arithmetic unit 65. The calculation result (f
6-F) by the spring constant Kt, a multiplier 74 that multiplies the outputs of the movement amount register 71 and the divider 73, and the outputs of the multiplier 74 and movement start position register 72. An arithmetic processing unit 60 additionally equipped with a computing unit 75 for computing, an input from the force/position converter 7 to the computing unit 81 explained in FIG. 3, and a functional block 81 to which the force/position converter 7 is deleted. A robot control unit 80 consisting of 84
, an arithmetic unit 91 that calculates the output of the multiplier 74 in the arithmetic processing unit 60 and the output of the encoder 94, an amplifier 92 that amplifies the output of the arithmetic unit 91, and a motor that rotates with the drive current output from the amplifier 92. 93 and an encoder 94 that is directly connected to the motor 93 and generates a signal according to the rotation of the motor 93.

Note that the resolution of the support table 50 in this embodiment is 1710 finer than the resolution of the robot 2.
It is assumed that the support table has a mechanism that moves in the same direction as the movement direction under the control of the support table control section 90.

Further, it is assumed that the stopper (b) is installed on a support table 50 having a higher resolution than the robot 2, and is located at a position X.

The tube grasped by robot hand 3 (al is
Position X of stop (b) by one step Δχ from position X1 to be pressed into stop (b).

move towards.

While the robot hand 3 is moving by this amount of movement ΔX, the stopper (
b), the force sensor 4 installed on the robot hand 3 generates a pressing force f0 proportional to the amount of movement ΔX.
can be detected.

At this time, if the pressing force f0 is larger than the target pressing force F required to attach the tube (a), the difference between the pressing force f0 and the target pressing force F (ro-F
) is calculated by the calculator 65.

Next, this difference (re-F) is a certain spring constant K.

A step m (where m''(foF)/Kt) proportional to the value ((fo - F)/Kt, ) obtained by dividing by is determined.

Next, the target position
The value (X, +m・Δ
Add Z).

Thereby, it becomes possible to approach the target pressing force F. That is, the above-described method allows force control to be performed at a resolution lower than the resolution of the robot 2.

Therefore, when the robot 2 performs work that requires force control, the positioning accuracy of the robot 2 may be relatively rough (even if the positioning accuracy is relatively low), and the control on the robot 2 side becomes easy.

Furthermore, by changing the spring constant Kt, the amount of movement of the support table 50 is changed, and by setting the spring constant Kt appropriately, it is possible to control the force most suitable for the work.

〔Effect of the invention〕

According to the present invention as described above, it is possible to easily obtain a pressing force that is less than the resolution of the robot 7) using a simple method, and moreover, it is possible to perform force control that is optimal for the work.

[Brief explanation of the drawing]

FIG. 1 is a block diagram explaining the present invention in detail, FIG. 2 is a block diagram explaining the present invention in detail, and FIG. 3 is a block diagram explaining a conventional example. In the figure, 1.10 is a control device, 2 is a robot, 3 is a robot hand, 4 is a force sensor, 5.50 is a support table, 6.60 is an arithmetic processing unit, 7 is a force/position converter, 8, 80 is the robot control unit, 6L72 is the start position register, 62.71 is the movement amount register, 63 is the card register, 64
．． 65, 75, 81.91 are arithmetic units, 73 is a divider, 7
4 is a multiplier, 82.92 is an amplifier, 83.
93 is a motor, and 84 and 94 are encoders, respectively. Figure 1

Claims (1)

[Claims] A robot (2) that performs a pressing operation using a hand (3) having a force sensor (4), the resolution of which is finer than that of the robot (2), and ) is provided, the mechanical means (50) having a finer resolution than the robot (2) is used as a pressing base, and the force sensor (50) attached to the robot hand (3) is Based on the signal of 4), the robot hand (3)
A pressing force control method for a robot, characterized in that the pressing force applied to an object to be pressed is adjusted together with the mechanical means (50) from a predetermined position of the robot.