JPH05154779A - Operation control device for robot - Google Patents

Abstract

PURPOSE:To safely teach the teaching point by providing a work instruction output means outputting the preset work instruction when the deviation between the measured position of a robot hand calculated by a position measured value calculating means and the work point data stored in a work point data memory means falls within a preset error. CONSTITUTION:A work point data memory means 107 selectively storing the teaching point data to output the work instruction among the teaching point data stored in a teaching point data memory means 101 is provided. The preset work instruction is outputted from a work instruction output means 108 when the deviation between the measured position of a robot hand calculated by a position measured value calculating means 106 and the work point data stored in the work data memory means 107 falls within a preset error. Teaching can be performed at a speed slower than the working speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motion control device for an industrial robot, and more particularly to a motion control device for a robot which performs a predetermined motion while moving a hand.

[0002]

BACKGROUND OF THE INVENTION It is well known that robots are widely used for automated production or inspection, but work is often done at pre-instructed work points, such as attaching parts or welding. However, when the work is stopped for each work point such as the inspection of the coated surface or the deburring of the injection-molded member, the work time becomes long and the productivity is lowered.

For example, in the case of inspecting a coating surface of an automobile for defects by using an automatic inspection robot described in Japanese Patent Application No. 1-210806, "Automatic inspection apparatus for coating film smoothness", the procedure is as follows. FIG. 5 is an explanatory diagram when the coating film smoothness of the automobile luggage 501 is inspected by an automatic inspection robot.

First, coordinates 511 and 5 are displayed on the surface of the luggage 501.
12 is set to teach the automatic inspection robot.
Next, the automobile luggage 501 is scanned by the automatic inspection robot, and a strobe is emitted each time the taught coordinates 511, 512, ... Are reached, and these coordinates 511, 51 are read.
Ranges 521 and 52 that are set in advance around 2 ...
Shoot 2 ... with a TV camera.

By subjecting this image to image processing, it becomes possible to find coating defects such as so-called spots, craters, and sags present in the coating film.

[0006]

FIG. 6 is an explanatory diagram of a method of controlling one hand of an automatic inspection robot, in which the horizontal axis represents time and the vertical axis represents moving speed and displacement of the hand. The trapezoidal speed commands 601 and 6 are provided to the robot hand in order to emit an image of the strobe at a predetermined position while moving the hand and capture an image.
Give 02 ...

Then, a deceleration command is issued from the previous speed command, and at the same time, an acceleration command is issued from the next speed command. Therefore, the synthetic speed 610 of the hand is a constant speed except immediately after activation. Moving the hand at a constant speed is important for maintaining productivity and quality.

Since the hand displacement command is an integral value of speed, the hand displacement command is a straight line 620 having a constant inclination.
Expressed as However, the actual displacement of the hand becomes a straight line 630 parallel to the straight line 620 indicating the displacement command, and a difference occurs between the displacement command and the actual displacement. Further, the light emission command is output at the same time when the deceleration command is output from the speed command.

Therefore, even if the strobe light emission is commanded immediately after the displacement command to the working point 512 of the automatic inspection robot is output, the range of 522 'centering on 512' is actually imaged. The cause of the difference between the displacement command and the actual displacement is as follows.

(1) It is impossible to realize, by software, the control of confirming that the target point has been reached during hand movement / operation and simultaneously issuing an input / output command. (2) There is an operation delay in the servo mechanism that drives the hand. (3) The hand itself has inertia. Therefore, in order to teach the automatic inspection robot to emit light at a predetermined working point, it is necessary to teach the point 512 ″ as a working point in consideration of the difference between the displacement command and the actual displacement.

The difference between the points 512 and 512 "is influenced by the operating speed, acceleration, delay of the servo system, the degree of inclination of the surface to be inspected from the horizontal plane, and the like, so that the working point can be taught with a predetermined accuracy. It takes a long time, for example, about 3 days to teach the working points of the hood, roof and luggage of a passenger car.

Further, the difference between points 512 and 512 "is also influenced by the moving speed of the robot hand.
When the teaching speed is different from the actual work speed, the intended range cannot be captured. Therefore, when confirming the teaching point, it is necessary to operate and confirm at the actual inspection speed, which increases the risk of work during teaching, and
It makes accurate teaching difficult.

The present invention has been made in view of the above problems, and it is possible to teach an actual working point without considering the delay of the servo system, the inclination of the inspection surface, etc., and shorten the teaching time. It is an object of the present invention to provide a robot control device capable of performing the above operations.

[0014]

FIG. 1 shows a motion control apparatus for a robot according to the present invention, which is a teaching point data storage means 101 for storing teaching point data for the robot and a teaching point data storage means 101 for storing the teaching point data. Position command generating means 102 for generating a position command by interpolating the teaching point data, speed command generating means 103 for generating at least one speed command from the position command generated by the position command generating means 102,
Servo amplifying means 104 for amplifying the deviation between the speed command value generated by the speed command generating means 103 and the measured speed value.
1 and a displacement measuring unit 1043 for actually measuring the displacement amount driven by the driving unit 1042 and the driving unit 1042 according to the deviation amplified by the servo amplifying unit 1041.
Servo control means 1051, 1052 ... 105N
And at least one servo control means 1051, 105
2 ... Displacement measuring means 1 included in each of 105N
Position measurement value calculation means 106 for calculating the actual position of the robot hand based on the displacement amount actually measured in 043, and teaching points from which teaching commands from the teaching point data stored in the teaching point data storage means 101 should be output. A work point data storage means 107 for selecting and storing data, a deviation between the actually measured position of the robot hand calculated by the position actual measurement value calculation means 106 and the work point data stored in the work point data storage means 107 is predetermined. And a work command output means 108 that outputs a predetermined work command when they match within an error.

[0015]

In the robot motion control apparatus according to the present invention, the work command is output when the actual position of the robot hand coincides with the teaching point within a predetermined error range. Therefore, it is possible to directly teach a point to actually work as a teaching point, and it is possible to teach at a speed slower than the working speed.

[0016]

FIG. 2 is a hardware configuration diagram of an embodiment of a robot motion control apparatus according to the present invention, which is configured as a so-called microcomputer system. Robot hands are so-called electric servo systems 2051, 2
052 ... 205N.

Each electric servo system 2051, 2052 ...
205N is a servo amplifier 2041 Servo motor 204
2 and a rotary encoder 2043. The speed command signal for each electric servo system output from the robot control computer unit 210 is the servo amplifier 204.
1 is supplied to one input terminal. Servo amplifier 204
The rotary encoder 20 is connected to the other one input terminal of 1.
The output of 43 is connected.

That is, the servo amplifier 2041 calculates the deviation between the speed command signal and the actual speed value calculated from the output of the rotary encoder 2043, and outputs a signal proportional to the deviation. The output of the servo amplifier 2041 rotates the servo motor 2042 to drive the robot hand.

A rotary encoder 2043 is directly connected to the drive shaft of the servo motor 2042, and the measured speed value calculated from the actual position of the robot hand is fed back to the servo amplifier 2041. The robot control computer unit 210 is centered on the bus 2101
102, memory 2103, input interface 210
4, an output interface 2105 and a communication interface 2106.

An input device 230 such as a keyboard or a teaching pendant is connected to the input interface 2104 and is used for teaching the robot the teaching point coordinates. The data of the teaching point taught at the teaching stage is temporarily stored in the memory 2103.

At the time of actual work, the teaching point data stored in the memory 2103 is read and the work is executed. Figure 3
Is a flowchart of a robot control routine executed by the robot control computer unit 210, and it is assumed that points 511, 512, ... Of FIG. 5 are taught as teaching points.

First, in step 301, the index i is reset to "1". In step 302, the coordinates of, for example, two teaching points P (i) and P (i + 1) (in the present embodiment, for example, points 511 and 512) are read out, and in step 303, the locus between these two teaching points is complemented. Calculate by calculation. Next, at step 304, the displacement data is decomposed into a rotation angle command of the servo motor which is a position command of at least one electric servo system.

At step 305, a speed pattern of movement is set from the position command, the moving speed, and the instruction value of the acceleration, and the speed command signal is calculated. The speed command signal is transmitted to the servo amplifier 2041 in step 306. In step 307, it is determined whether the pattern of the speed command signal has reached the deceleration point.

If a negative decision is made in step 307, the operation proceeds to step 308, the index i is incremented, and the operation returns to step 302. When a positive determination is made in step 307, this routine ends. In the present invention, a work instruction computer unit 220 is further installed. The work instruction computer unit 220 is centered on the bus 2201 and has a CPU 2202, a memory 2203, an input interface 2204, and an output interface 2205.
And a communication interface 2206.

The input interface 2204 of the work command computer unit 220 includes electric servo systems 2051 and 20.
The output of the rotary encoder 2043 installed at 52 ... 205N is connected, and the output of the rotary encoder 2043 is periodically read by the work command computer unit 220. The output interface 2205 of the work command computer unit 220 has, for example, a strobe 25.
0 and the image processing device 260 are connected.

The communication interface 2106 of the robot control computer unit 210 and the communication interface 2206 of the work command computer unit 220 are connected by a high-speed communication line 240, and work is performed from the teaching points taught to the robot control computer unit 210. The point data is selected and the memory 2 of the work command computer unit 220 is selected.
It is transmitted to 203.

In this embodiment, teaching points 511 and 5 are provided.
12 ... are all work points. FIG. 4 is a flowchart of a work instruction routine executed by the work instruction computer unit 220. In step 401, the index j is reset to "1". Communication line 24 in step 402
The coordinates of the work point data S (j) (for example, the point 511 in this embodiment) are read via 0.

In step 403, the output of the rotary encoder 2043 installed in at least one electric servo system 2501, 2502, ... 250N is read. In step 404, the read output of the rotary encoder 2043 is combined to synthesize the current position T of the robot hand.
To calculate. In step 405, it is determined whether the error between the current position T and the work point S (j) taught in advance is less than or equal to a predetermined value ε.

When a negative determination is made in step 405, the process returns to step 403. On the contrary, if an affirmative decision is made in step 405, the operation proceeds to step 406 and, for example, the strobe 25
0 or an operation command is output to a device which is the image processing device 260. In step 407, it is determined whether or not the output of the work command has been completed for all the work points, and if the determination is affirmative, this routine ends.

If a negative decision is made in step 407, the operation proceeds to step 408, the index j is incremented and the operation returns to step 402. As described above, in this embodiment,
I explained the paint surface inspection robot using a TV camera, but also work that requires so-called deburring of synthetic resin parts or application of sealing material to synthetic resin parts or glass while controlling the clamp state of parts while moving the hand Obviously, it can also be applied to the teaching of robots that perform.

[0031]

In the robot motion control apparatus according to the present invention, the work command is output when the actual position of the robot hand coincides with the teaching point within a predetermined error range. It is possible to obtain the effect. (1) Since the working point itself can be taught to the robot as a teaching point, the teaching time can be shortened to about one-third that of the conventional method, and a model change can be flexibly dealt with. (2) Since the working point itself can be taught as a teaching point, setting the teaching speed to a slow value allows the teaching point to be taught safely. (3) The horizontality and the curvature of the work surface do not matter, and it can be applied to the teaching of work on inclined surfaces and curved surfaces. (4) The time required to teach the robot how to teach the robot is shortened, and the skill level of the work may be low.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram of an operation control device for a robot according to the present invention.

FIG. 2 is a configuration diagram of an embodiment.

FIG. 3 is a flowchart of a robot control routine.

FIG. 4 is a flowchart of a work instruction routine.

FIG. 5 is an explanatory diagram of automatic coating film smoothness inspection.

FIG. 6 is an explanatory diagram of a hand control method.

[Explanation of symbols]

 101 ... Teaching point data storage means 102 ... Position command generation means 103 ... Servo command generation means 1041 ... Servo amplifier 1042 ... Servo motor 1043 ... Rotary encoder 1051 ... 105N ... Servo control means 106 ... Measured position value calculation means 107 ... Work Point data storage means 108 ... Work command output means

Claims (1)

[Claims] 1. A teaching point data storage means for storing teaching point data of a robot, a position command generating means for interpolating teaching point data stored in the teaching point data storage means to generate a position command, and the position. Speed command generating means for generating at least one speed command from the position command generated by the command generating means, and servo amplifying means for amplifying the deviation between the speed command value generated by the speed command generating means and the measured speed value At least one servo control means, each of which comprises a driving means for driving the robot hand according to the deviation amplified by the servo amplifying means, and a displacement measuring means for actually measuring the displacement amount driven by the driving means; The actual position of the robot hand is calculated based on the displacement amount actually measured by the displacement measuring means included in each of the at least one servo control means. Actual position measurement value calculating means, working point data storage means for selecting and storing teaching point data for which a work command should be output from the teaching point data stored in the teaching point data storage means, and the actual position measurement value Work command output means for outputting a predetermined work command when the deviation between the measured position of the robot hand calculated by the calculation means and the work point data stored in the work point data storage means matches within a predetermined error, A robot motion control device.