JPS6314657B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a painting robot, which is suitable for automatically painting large objects such as automobile bodies using the painting robot.

Generally, when automatically painting objects that have a large painting area, such as the body of a car,
Conventionally, a method has been widely adopted in which the object to be coated is placed on a conveyor and conveyed, and the painting robot is caused to paint while traveling in the same direction as the conveyance direction of the object.

By the way, if the conveyor stops due to a power failure or an accident while the painting robot is transferring the object to be painted, or if a mistake occurs in the painting process, the power switch must be turned off. There may be times when it is necessary to stop the conveyor. In such a case, painting will be interrupted midway. When the conveyor is restarted from this state and the remaining parts of the object to be coated are continued to be coated, a boundary appears between the part painted before the conveyor stopped and the part to be painted after restarting, and the paint film becomes uneven. As a result, the quality of the coating deteriorates significantly. For this reason, when the conveyor is interrupted, a large number of workers have to paint the remaining parts, and it is necessary to secure personnel for this, so even if industrial robots are introduced, it will not result in labor savings. It was hot.

The present invention was developed in view of the above-mentioned problems of the conventional technology, and even when the conveyor stops during painting using a painting robot, painting of a predetermined area is finished, thereby improving painting quality. An object of the present invention is to provide a method for controlling a painting robot.

In order to solve this problem, the present invention provides a coating robot that paints objects to be coated that are conveyed on a conveyor, a traveling mechanism that causes the coating robot to travel parallel to the conveyor, and a robot that paints objects that are conveyed on a conveyor. a position sensor attached to the conveyor for detecting passage of the object to be coated to a reference position; a pulse generator for generating a pulse signal every time the conveyor moves a predetermined distance; and a relative position of the painting robot with respect to the object to be coated; A method for controlling a painting robot, comprising a control device for controlling painting work contents such as displacement of joints of the painting robot, paint discharge, and stopping, and a stop detection means for detecting a stoppage of the conveyor, the method comprising: A step of separating the painting surface of the object to be painted and dividing it into a plurality of painting blocks for each part that can be painted, teaching the contents of the painting work for each painting block and storing it in advance in the control device, and a step of a step of detecting the position of the object to be coated by a pulse signal from the pulse generator after the position sensor detects that the object to be coated being conveyed to the conveyor has passed a reference position; After facing the painting block, the traveling mechanism is made to travel in the same direction as the conveyor at the same speed, thereby maintaining the relative position between the painting robot and the object to be painted constant, and controlling the robot to control the control device. a step of performing a painting operation based on the memorized teaching; and a step of displacing the painting robot to the next painting block by displacing the painting robot relative to the object to be painted after finishing painting the first painting block. , and then again performing the painting operation on the next painting block while keeping the relative position between the painting robot and the object to be painted constant, and further during the painting operation on any of the painting blocks. When the stop detection means detects that the conveyor has stopped, the painting robot stops moving to finish painting the painting block;
Thereafter, the painting robot stops the painting operation.

With this configuration, if the conveyor stops while the painting robot is painting one of the painting blocks, the stoppage of the conveyor is detected by the stop detection means, and a detection signal is input to the control device. By doing so, the painting of the painting block is completed while maintaining the relative position between the painting robot and the object to be painted, and then the painting robot is stopped from painting until the conveyor is driven again.
After the conveyor is re-driven, painting of subsequent paint blocks continues. As a result, it is possible to prevent the coating film of the object from becoming uneven during the coating operation before and after the conveyor stops, and to maintain good coating quality.

Embodiments of the present invention will be described below based on the drawings.

First, FIGS. 1 and 2 show a case in which a painting robot is used to paint the body of an automobile. In the figure, 1 is a painting robot, and the painting robot 1 has a base 2, a turntable 3 provided on the base 2, and a first rotatable rotatable robot 1 installed on the turntable 3. arm 4, a second arm 5 rotatably attached to the upper end of the first arm 4, a wrist 6 whose tip end is bendable, and a wrist 6 attached to the wrist 6. It is roughly composed of a coating machine 7. The robot 1 is mounted on a traveling carriage 9 installed on rails 8, 8 laid in a pit of a painting booth. The traveling carriage 9 is able to travel along the rails 8 by a traveling drive means (not shown), and the traveling mechanism of the robot 1 is controlled by the traveling carriage 9 and the traveling driving means. configured.

Reference numeral 10 denotes a car body as an object to be coated, and the car body 10 is placed on a trolley 11 and conveyed by conveyors 12, 12.
It is transported along the top in the direction of the arrow in FIG. The painted surface of the vehicle body 10 is divided into parts that can be painted separately and divided into a plurality of painting blocks a, b,
c, d, and e are formed. For example, as shown in FIG. 1, painting block a covers the area from the front part of the vehicle body 10 to the side corner parts, painting block b covers the area from the front side part to the front door attachment part, and painting block c covers the front and rear parts. The door area, painting block d, is the rear side area behind the rear door, and the painting block e is the rear area. Each of the painting blocks a to e is set in a range that can be painted while keeping the relative position between the robot 1 and the vehicle body 10 constant.

FIG. 3 shows a circuit diagram of the control device of the painting robot 1. In the figure, reference numeral 21 denotes a pulse generator that emits a pulse every time the conveyor 12 is transferred by a predetermined amount, and the pulse generator 21 is connected to a gate circuit 22. A position sensor 23 is disposed at a reference position of the conveyor 12 and detects when the vehicle body 10 has passed the reference position.The position sensor 23 is connected to a flip-flop circuit 24. When it passes, a signal is input from the position sensor 23 to the flip-flop circuit 24, which outputs a gate open signal based on the data output of the flip-flop circuit 24, and the gate circuit 22
is configured to open. Then, when the gate circuit 22 is opened, pulses from the pulse generator 21 are momentarily input to the counting circuit 25 via the gate circuit 22, and by counting the number of input pulses, the position of the vehicle body 10 is detected. Next, a potentiometer 26 is attached to the rail 8 and detects the position of the painting robot 1 by changing the voltage;
Reference numeral 27 denotes a potentiometer that is installed at the joints of the robot 1 including the turntable 3, first and second arms 4, 5, wrist 6, etc., and outputs the displacement of each joint as a change in voltage. 2
5. Signals from the potentiometers 26 and 27 are sent to the arithmetic processing unit 2 via an input control device (not shown).
8 to the storage device 29, and this circuit structure can be used to store the teaching contents of the painting work.

On the other hand, in order to read out the painting work contents stored in advance in the storage device 29 and perform a playback operation, the arithmetic processing device 28 starts operating when the vehicle body 10 passes the position sensor 23 according to the control program, While constantly detecting the position of the vehicle body 10 based on pulse signals inputted from the pulse generator 21, the content of the painting work at each position of the vehicle body 10 can be read out from the storage device 29 and output. Among the contents of the painting work, the position of the robot 1 is controlled by driving the traveling drive means of the traveling carriage 9 via a D/A converter 30, a comparator 31, and a servo amplifier 32. In addition, the movements of the robot 1 itself, such as the displacement of the joints of the robot 1, the discharging of paint, and the stopping of the robot 1, are controlled by each actuator that constitutes the operating mechanism of the robot 1 via a D/A converter 33, a comparator 34, and a servo amplifier 35. It is controlled by operating the . The comparators 31 and 34 adjust the operation of the robot 1 by constantly comparing the command content output from the arithmetic processing unit 28 and the actual operation of the robot 1 output from the potentiometers 26 and 27, respectively. This is provided to prevent malfunctions from occurring.

Next, 36 is a stop detection means for detecting a stop when the conveyor 12 is stopped due to a power failure, a switch disconnection, etc. The input side of the stop detection means 36 is connected to the pulse generator 21 via a gate circuit 22. The pulse signal from the pulse generator 21 is input every moment, and the stop detection means 36 detects the missing pulse when the arrival of pulses stops for a predetermined time interval or more after the start of pulse signal reception. .
The output side of the stop detection means 36 is connected to an alarm device 37 consisting of a buzzer or the like to warn that the conveyor 12 has stopped, and is also connected to the arithmetic processing unit 28 to output a stop signal for the conveyor 12. Furthermore, 38 is a control pulse generator that generates pulses at approximately the same pulse intervals as the pulse generator 21, and when the stop signal of the conveyor 12 is input to the arithmetic processing unit 28, the control pulse generator 38 performs the arithmetic operation. It is configured to output a pulse signal to the arithmetic processing unit 28 in response to a signal from the processing unit 28 to control the data sending speed regarding the content of the painting work.

Next, the teaching operation of the painting robot will be explained based on the above-mentioned circuit.

First, the car body 1 to be painted is placed on the conveyor 12.
0 is placed and the vehicle body 10 is transported. and,
When the vehicle body 10 passes the position sensor 23, a gate open signal is inputted from the flip-flop circuit 24 to the gate circuit 22, and a pulse signal from the pulse generator 21 is inputted to the counting circuit 25 every moment. Then, the conveyor 12 is stopped when the vehicle body 10 is at an appropriate position, and the distance of the vehicle body 10 from the reference position at this time is stored in the storage device 29.
Therefore, the traveling carriage 9 is moved and placed in the optimum position for the robot 1 to paint the entire painting block a to be painted first. The position of the robot 1 is detected by the potentiometer 26 and stored in the storage device 29. At this position, a teaching handle is attached to the coating machine 7, and by moving the joints of the robot 1, the robot 1 is taught the coating work of the coating block a. The movement of this joint is converted into a signal by the potentiometer 27, and is stored in the storage device 29 together with the coating information regarding the coating machine 7. When the teaching of the content of the painting work on painting block a is completed, a block end mark is input into the storage device 29. By this, the fourth
As shown in the figure, data A ₁ consists of information regarding the distance from the reference position of the vehicle body 10 to the painting start position, information regarding the relative position of the robot 1 to the vehicle body 10 at that position, information regarding joint movements, paint information, etc. A data group A consisting of A ₂ , A ₃ , . . . and block end mark A _BEM is obtained.

Next, while leaving the vehicle body 10 as it is, the robot 1 is moved in the direction opposite to the arrow in FIG. 1 and stopped at the optimal position for painting the entire painting block b. This relative displacement of the robot 1 with respect to the vehicle body 10 is input from the potentiometer 26 to the storage device 29. Then, at this position, the content of the painting work for painting block B is taught, and then by inputting the block end mark, data group B consisting of data B ₁ , B ₂ , B ₃ , ... and block end mark B _BEM is created. get. In this way, the data groups C, D, and E relating to each painting block c, d, and e are created in sequence, and the teaching work is completed by inputting the end mark END after the last data group E.

Here, a block end mark is input each time the teaching for each painting block is completed, but this indicates that the painting work for only that painting block has been completed, and the teaching information for the next painting block continues. means remembered. On the other hand, the end mark means that the entire painting of the object to be coated has been completed, and reading out this end mark during the playback operation means that the reading out of all the teaching information has been completed.

The playback operation for actually painting the vehicle body 10 based on the teaching information obtained as described above is performed as follows. First, the vehicle body 10 is placed on the conveyor 12, and the vehicle body 10 is conveyed by driving the conveyor 12. And car body 1
When 0 passes the position sensor 23, a signal is sent from the flip-flop circuit 24 to the arithmetic processing unit 28, and reading of data from the storage device 29 is started. At the same time, a pulse signal from the pulse generator 21 is inputted to the arithmetic processing unit 28 every moment, and the arithmetic processing unit 28 constantly detects the position of the vehicle body 10. Therefore, the arithmetic processing unit 28 reads from the storage device 29 information regarding the painting start position of the vehicle body 10 and information regarding the relative position of the robot 1 with respect to the vehicle body 10 at that position, and the D/A
The traveling drive means is operated via the converter 30 and the servo amplifier 32, and the robot 1 is displaced from the right end position in FIG. 1 to the designated position to start painting the painting block a. Robot 1 and vehicle body 1
0, the robot 1 is transported at the same speed as the vehicle body 10 by operating the traveling drive means in synchronization with the pulses from the pulse generator 21. During this time, the arithmetic processing unit 28 Information regarding joint movement, paint discharge, stopping, etc. is output from the robot 1 to the servo amplifier 35 via the D/A converter 33.
The painting block a is painted by making each actuator perform an operation according to the teaching content. When painting of painting block a is completed, block end mark A _BEM is read out.

When the arithmetic processing unit 28 reads the block end mark A _BEM of the painting block a, it is recognized that the painting work based on the data group A has been completed, and the reading of the painting data B of the painting block b is subsequently started. Therefore, first, information regarding the relative position of the robot 1 with respect to the vehicle body 10 at the painting block b is read out from the storage device 29, and the robot 1 immediately retreats in the direction opposite to the arrow in FIG. 1 and starts painting the painting block b. Move to the specified position to start robot 1 again.
By being transported at the same speed as the vehicle body 10, painting is performed in the painting block b.

In this way, each painted block b, c,
When the arithmetic processing unit 28 reads out the end mark END after painting d and e, the entire painting work on the vehicle body 10 has been completed. Therefore,
The robot 1 is returned to the starting position and waits for the next vehicle body to be painted.

By the way, the conveyor 12 may come to a halt during painting work on any of the painting blocks due to an accident such as a power failure or a disconnection of a conveyor control switch. At this time, the pulse generator 21
The travel drive means that operates in synchronization with the pulse signal from the vehicle also stops at the same time. Therefore, the stop detection means 36 that detects the non-arrival pulse is activated when the pulse signal from the pulse generator 21 is not input for a certain period of time or more, and drives the alarm device 37 to instruct the operator to stop the conveyor 12. At the same time, a stop signal is input to the arithmetic processing unit 28. Based on this stop signal, the arithmetic processing unit 2
The control pulse generator 38 is accessed from 8, and the pulses from the control pulse generator 38 are inputted. As a result, the arithmetic processing unit 28 is controlled by the pulse signal from the control pulse generator 38 to send data regarding the content of the painting work at the relative position of the robot 1 and the vehicle body 10 on the painting block. Painting continues. In this case, the traveling drive means is the conveyor 1
Since the drive of robot 2 is stopped at the same time as robot 2 is stopped, the relative position between robot 1 and vehicle body 10 is maintained in a state suitable for painting on the painting block. Then, the arithmetic processing unit 28 causes the robot 1 to perform painting work based on the teaching information until the block end mark of the painting block is read out, and when the block end mark is read out, regardless of the presence or absence of the subsequent painting block, The reading of data from the storage device 29 is stopped, and the operation of the robot 1 is stopped. After that, when the conveyor 12 is driven again, the pulse signal from the pulse generator 21 will be input to the arithmetic processing unit 28 again, so the data reading by the arithmetic processing unit 28 will be resumed, and the robot will 1 to perform the painting in the subsequent painting block.

As described in detail above, according to the method for controlling a coating robot according to the present invention, a plurality of coating blocks are formed by dividing the coating surface of the object to be coated into sections that can be coated separately. Then, the content of the painting work is taught for each painting block, and based on this teaching content, the painting robot is operated in playback to paint the object to be painted, and the conveyor stop detection means is controlled by the painting robot. By attaching it to the device, if the conveyor stops while the painting robot is painting any of the painting blocks, the stoppage of the conveyor is detected by the stop detection means, and the painting robot and We have adopted a method in which the coating of the painting block is finished while maintaining its relative position with the object to be painted, and then the operation of the painting robot is stopped until the conveyor is driven again. This prevents the paint film from becoming uneven due to the painting work before and after the conveyor stops, and prevents the paint from being rejected as a defective product, which improves painting efficiency and maintains the quality of the painting. can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a painting robot that paints the body of an automobile, FIG. 2 is a right side view of FIG. 1, and FIG. 3 is a specific example of the method for controlling the painting robot according to the present invention. The circuit diagram, FIG. 4, is a diagram showing data to be stored in the storage device of FIG. 3. 1...Painting robot, 8...Rail, 9...
Traveling trolley, 10... object to be coated, 12... conveyor,
21...Pulse generator, 22...Position sensor, 2
5... Counter, 26, 27... Potentiometer, 28... Arithmetic processing unit, 29... Storage device,
36... Stop detection means, a, b, c, d, e...
Painted block, A, B, C, D, E...data group.

Claims (1)

[Claims] 1. A coating robot that performs coating on an object to be coated conveyed on a conveyor, a traveling mechanism that causes the coating robot to run parallel to the conveyor, and a traveling mechanism attached to the conveyor that allows the object to be coated to pass through a reference position. a position sensor for detection, a pulse generator for generating a pulse signal every time the conveyor moves a predetermined distance, a relative position of the painting robot with respect to the object to be painted, displacement of the joints of the painting robot, and discharge of paint. , a method for controlling a painting robot having a control device for controlling the content of painting work such as stopping, and a stop detection means for detecting a stoppage of the conveyor, the method comprising: separating the painting surface of the object to be coated for painting; A process of dividing the work into a plurality of painting blocks for each possible part and teaching the contents of the painting work for each painting block and storing it in advance in the control device, and at the time of playback, moving the workpiece to be conveyed to the conveyor to the position. A step of detecting the position of the object to be coated using a pulse signal from the pulse generator after the sensor detects that the object has passed the reference position, and a step of changing the traveling mechanism after the painting robot faces the first painting block. A step of causing the painting robot to travel in the same direction at the same speed as the conveyor, thereby maintaining a constant relative position between the painting robot and the object to be painted, and performing painting work based on the teaching stored in the control device. and, after finishing painting the first painting block, displacing the painting robot relative to the object to be painted to move to the next painting block, and then moving the painting robot and the object to be painted again. a step of performing painting work on the next painting block while maintaining a constant relative position between the conveyor and the object; further, the stoppage detection means detects a stoppage of the conveyor during the painting work on any of the painting blocks; A method of controlling a painting robot, which sometimes comprises the steps of stopping the movement of the painting robot to finish painting the painting block, and then stopping the painting operation of the painting robot.