JPS59136815A - Drive controller of robot - Google Patents

Abstract

PURPOSE:To avoid a big shift of a mobile part of a robot due to noises by compensating the deviation between the present value and the target value of the mobile part in a positioning mode of the mobile part in case the degree of variation of said deviation generated every unit time exceeds the limit value. CONSTITUTION:The present value PX of the mobile part of a robot is detected by a position detector 13 attached to the output shaft of a motor 10 which drives said mobile part. A subtractor 14 delivers the deviation (e) between the value PX and the target value P. When the mobile part gets into a prescribed positioning range, a comparator 16 delivers a positioning signal (a). Then a comparator 26 delivers a limit value exceeding signal (b) when the absolute value ¦e'¦ of the variation degree of the deviation (e) generated every unit time exceeds the limit value emax set by a limit value setter 28 of a limit value excess detecting output means 21. A deviation compensating means 29 compensates the deviation (e) to reduce the variation degree e' less than the limit value when signals (a) and (b) are delivered. Thus a big movement of the mobile part is suppressed even though the noises are put on the output line of the detector 13. This improves the positioning accuracy of a robot.

Description

[Detailed description of the invention] The present invention relates to a drive control device for robots 1 to 1.

First, an example of a conventional robot and its drive control device will be described with reference to FIGS. 1 and 2.

The articulated robot shown in Fig. 1 has a base 1 and a base 1.
A shoulder 2 rotatably mounted on the upper surface in the direction of arrow A about an axis 1α perpendicular to the surface, an upper arm 3 connected to the shoulder 2 so as to be rotatable in the direction of arrow B about the axis 2α, and this upper arm. The shaft is at the tip of 3! a first lower arm 5 connected to the distal end of the middle arm 4 so as to be pivotable in the direction of the arrow C by a shaft 4a; A second lower arm 6 is rotatably connected in the direction of the arrow E by a shaft 5α provided at the tip of the second lower arm 5 in a direction orthogonal to the shaft 4a, and the second lower arm 6 is rotatable in the direction of the arrow F by the shaft 6a. The mechanical hand 8 or the wrist 7 to which a welding gun or the like is attached constitutes six axes that can be connected together.

A drive motor (not shown) is attached to each movable part from the shoulder 2 to the wrist 7, and these drive motors are controlled by a drive control device shown in FIG. The movable part is driven.

Next, the outline of the drive control device for the robot shown in FIG. 1 will be explained with reference to FIG. 2.

In addition, in the same figure, in each movable part from the shoulder part 2 to the wrist 7, only the block circuit related to the shoulder part 2 is specifically shown, but each circuit related to each movable part from the upper arm 3 to the wrist 7 is shown in detail. Since the configuration is exactly the same as 2, the explanation thereof will be omitted.

In the figure, the microcomputer 9 constituting the control unit of the robot is configured to control target value data P indicating the total rotation amount of the motor 10 that drives the shoulder 2 and positioning range data Δe (absolute value), which is a predetermined value. ) as well as target value data and positioning range data for each movable part from the upper arm 3 to the hand 7.

In the target value register 11, the target value data P output from the microcomputer 9 is written.6 In the current value register 12, data as a position detector attached to the output shaft 10a of the motor 10 via a speed reducer (not shown) is written. For example, current value data PX indicating the current value of the shoulder portion 2 from the photoelectric absolute encoder 13 is written.

Note that the code disk in the absolute encoder 13 is
A speed reducer (not shown) attached to the output shaft 10α of the motor 10 allows the shoulder 2 to rotate once within the maximum movable range, and the current value data written in the current value register 12 (1) X is the rotation of the motor 10. It will be updated accordingly.

The current value data PX from the absolute encoder 13 is also input to the microcomputer 9 and is provided as data for displaying the current value of the shoulder 2, for example.

The subtracter 14 subtracts the current value data px of the current value register 12 from the target value data P of the target value register 11 to obtain the deviation amount e between the two.

The function generator 15 is for determining a part of the position loop gain KV of this drive control device, and for example, as shown in FIG.
A speed command V is output.

Note that the 1-position loop gain KV is the total value of the amplification factor (gain) of the 1-position feedback servo loop, and the shoulder 2
It is defined as the value obtained by dividing the operating speed V (+am/1; e C) by the deviation amount e (van).

Therefore, this position loop gain KV also includes the servo amplifier's daily gain, which will be described later.

The comparator 1st is the absolute value 1e of the deviation amount e output from the subtractor 14! (obtained by an absolute value circuit not shown) and the positioning range data Δe of the positioning range register 17 written by the microcomputer 9, and only when e≦Δe, the positioning signal a is sent to the microcomputer 9. Output to.

That is, the deviation amount e, which is the output of the subtractor 14, decreases as the drive amount (rotation amount) of the shoulder portion 2 approaches the target value P, so the positioning range data Δ, which is a predetermined value, becomes smaller.
By determining whether the absolute value 161 of the deviation amount e has reached e, it is possible to know whether the shoulder portion 2 has entered the positioning range (region).

Note that the reason why such a determination is made is to perform the following control.

That is, to specify the trajectory of the tip of the robot and the posture of the robot while the tip of the robot (mechanical hand 8 in the case of FIG. 1) moves to the final target position.

The target value data to be written to each target value register from the shoulder 2 to the wrist 7 has a plurality of relay points set between each origin and the final target position. Therefore, if we take the example of the drive control device for the shoulder section 2 shown in the figure, the target value data indicating each passing relay point is set to P1 to pn-1y.
If the target value data indicating the final target position is Pn, the comparator 16 determines whether or not the shoulder 2 has entered the positioning range from PI to Pn-1, and the microcomputer 9 writes P2 to pn into the target value register 11 in order.

Note that if this is done, the shoulder portion 2 will not accurately reach each passing relay point of P1 to Pn-+, and the %N force 1Δe will not reach each passing relay point, for example, 4.
Since the setting is on the ~5 side, the problem number is 1゜The D/A converter 18 converts the speed command υ of the function generator 15 force 1 into a speed voltage signal 5V14 which is an analog value, and converts the servo amplifier 1 day. is the difference between this speed voltage SvI and the speed feedback voltage signal Sv2 output from the tachogenerator 20 attached directly to the output shaft 10a of the motor 10. A voltage signal SV3 is output to the motor 10 by amplifying the difference. to rotate the motor 10, thereby applying the origin force to the shoulder 2)
to the final target position.

By the way, the above-mentioned robot drive control device has the following problem.

In other words, since the absolute encoder number that detects the current position of each movable part of the robot is attached via the output shaft 1 of the motor provided in each movable part and the reducer, as described above, each output (word line Each output signal wire is routed to a drive control device in a control panel separate from the robot shown in FIG.

The influence of this noise is not so much of a problem during the movement of each movable part of the robot, especially when each movable part is in the final target position and within the vertical positioning range. When the current value data suddenly changes due to relatively large noise, the amount of deviation generated in response to this change causes the moving part force to move, especially the tip of the robot where the movements of each moving part are synthesized. There were some problems such as it moving.

In view of the above-mentioned points, it is an object of the present invention to reduce as much as possible the influence of zero-temperature noise that occurs when the movable part of the robot enters the above-mentioned positioning range.

For this purpose, the device for controlling the drive of robots 1 to 1 according to the present invention is configured such that when the movable part force 1 of the robot is within a predetermined vertical positioning range, the device is attached to the output shaft of the motor that drives the movable part. If the amount of change in LJ per unit time of the deviation amount between the current value and the target value of movable @S (detector force) exceeds the predetermined limit value, reduce the amount of change to below the limit value. The amount of deviation is corrected so that

Embodiments of the present invention will be described below with reference to FIGS. 4 and 5 of the drawings.

FIG. 4 is a block diagram showing an embodiment of the present invention.

In FIG. 4, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and the explanation of those parts will be omitted.

In the figure, reference numeral 21 denotes limit value over detection means, which functions as follows.

That is, the latch circuit 22 receives the clock pulse CK output from the oscillator 23 as shown in FIG.

The first timing pulse C, which is output from the timing circuit 24 at each rising timing of 2 (see FIG. 5 (b)), is applied to a deviation amount correction means 29, which will be described later.
The deviation m which is the output of the second data selector 33 at
ex is latched, and the subtracter 25 outputs a second timing pulse CK3 (FIG. 5(c)) output from the timing circuit 24 at each falling timing of the clock pulse CK.
In order to subtract the deviation amount ex latched in the latch circuit 22 from the deviation amount e from the subtracter 14 at each timing (see), the subtracter 25 outputs a clock pulse CK.

The amount of change in the deviation amount e per unit time determined by the pulse width of is output.

Then, the comparator 26 compares the value 1;1 obtained by converting the change amount 2 outputted from the subtracter 25 into an absolute value by the absolute value circuit 27 and the limit value e wax preset in the limit value setting 1828. , let>emax, outputs a limit value over signal S.

Reference numeral 29 denotes a deviation amount correction means, which functions as follows.

That is, the adder 60 adds to the deviation amount ex latched by the latch circuit 22 in the limit value over detection means 21,
The encoder 61 adds the limit value e wax (+ e max or -e max) of the limit value setter 28 which is given the same sign as the sign of the change amount 2 which is the subtraction result of the subtracter 25 .

For example, if the sign of the amount of change e is "+", then ex + etaa
If x, r-J, then e DC-e @ay (.

The first data selector 32 is connected to the limit value over detection means 2.
When the limit value over signal is not inputted from the comparator 26 in 1, the deviation amount e from the subtractor 14 is selected;
While the limit value over signal is being input, the addition result of the adder 30 is e + e max or ex - e m
Select aX.

The second data selector 33 selects the deviation amount e from the subtracter 14 when the positioning signal a is not inputted from the comparator 16, which is a positioning range detection means, and selects the deviation amount e from the subtracter 14 while the positioning signal a is inputted. The selection result of data selector 32 of No. 1 is selected.

Therefore, in the deviation ie which is the output of the second data selector 33, when the shoulder part 2 is moving and the positioning signal a is not output from the comparator 16, the deviation amount e which is the output of the subtractor 14 is the same. When the shoulder portion 2 is within the positioning range and the positioning signal a is output from the comparator 16, if leI≦elnaX, the deviation amount e is itself, and if l e I > gmax, ex+eIIlaz
or e'A-emax (however, this ex is latch circuit 2
2).

In other words, the deviation amount correction means 29 makes the amount of change e less than or equal to the limit value emax ( In this case, the deviation amount gz latched in the latch circuit 22 is corrected so that it becomes (emax).

Each drive control device (not shown) from the upper arm 3 to the wrist is configured in exactly the same way as the drive control device for the shoulder 2, so each movable part from the shoulder 2 to the wrist 7 in the robot. When entering the positioning range and making slight movements or stopping, even if relatively large noise is added to the output signal line of each Abflue 1-encoder and the deviation amount e changes greatly, each change will be suppressed to the limit value e max. Therefore, the mechanical hand 8, which is the tip of the robot, does not move significantly due to noise.

In the above embodiment, the comparator 16, which is the positioning range detection means, is connected to each passing relay point P1 to P1 described in the conventional explanation.
A positioning signal a is output for each positioning range of Pn-1 and final target position 1]r1, but each passing relay point P1 to
Since the movement due to noise at Pn-1 is not much of a problem, only the positioning signal a at the final target position Pn is used for the second
Data selector! A gate circuit input to +3 may be provided.

Furthermore, in the above embodiment, the second data selector! The deviation amount ex, which is the output of the subtractor 13, is latched by the latch circuit 22, but instead of this, the deviation amount e, which is the output of the subtracter 14, is
may be latched.

As explained above, according to the present invention, even if noise is on the output signal line of the position detector that detects the current position of the robot's movable part, the movable part will not move significantly during positioning, and the robot It is possible to improve positioning accuracy and improve safety and stability.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing an example of the configuration of robot 1-;
1 is a block diagram showing a conventional example of the robot drive control device shown in FIG. 1, FIG. 3 is a diagram for explaining the function generator in FIG. 2, and FIG. 4 is an embodiment of the present invention. Block configuration diagrams showing examples, FIGS. 5(a) to 5(c), respectively show the latch circuit 22 of FIG.
and a timing chart for explaining the operation of the subtracter 25. 9...Microcomputer 10...Motor 1
1...Target value register 12...Current value register 1
3...Absolute encoder (position detector) 14
...Subtractor 16...Comparator (positioning range detection means) 21...
Limit value over detection means 22...Latch circuit 25...Subtractor 26...
・Comparator 28...Limit value setter 2nd...
Deviation amount correction means 30...Adder 31...Encoder! 12.32...1st. Second data selector Figure 5-82-

Claims (1)

[Scope of Claims] 1. The motor is driven in accordance with the amount of deviation between the current value of the movable part and a target value, which is detected from a position detector attached to the output shaft of a motor that drives the movable part of the robot. In robot drive control devices. positioning range detection means for outputting a positioning signal when the movable part enters a predetermined positioning range; and outputting a limit value over signal when the amount of change in the deviation amount per unit time exceeds a predetermined limit value. limit value over detection means for detecting a limit value, and only when the positioning range detection means outputs a positioning signal and the limit value over detection means outputs a limit value over signal, the amount of change is made equal to or less than the limit value. A drive control device for a robot 1-, characterized in that a deviation amount correcting means for correcting the deviation amount is provided.