JPH04189487A - Industrial robot - Google Patents

Abstract

PURPOSE:To prevent generation on of abnormal stop according to operation range over and perform stable operation of a work line by shifting a position where a robot main body operates to the center side of the movable range thereof in response to a speed change of a conveyor. CONSTITUTION:When a speed of a conveyor 4 changes, the central position of a range in which a work moves is shifted to the center of the movable range of a robot main body 2 during the operation of the robot main body 2 by means of a control device 1. Thereby if an operation range required to the robot main body 2 is less than the maximum operation range thereof after the speed change of the conveyor 4, the work can be continued by the same instruction program, without generating any operation range over.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a system for an industrial mouthpiece 1 that performs work such as painting on a workpiece conveyed by a conveyor.

``Prior Art'' In recent years, industrial robots have been used in various fields as automated machines that perform tasks such as painting in place of humans, and can flexibly handle a variety of workpieces by changing their operating programs.

This type of industrial robot is often used in flow production lines, etc. In this case, the robot body is placed near the workpiece transport path and performs work on the workpiece during transport. . For this reason, industrial robots are usually provided with a conveyor synchronization function that operates in synchronization with the conveyance path of the workpiece.

However, conventionally, this conveyor synchronization function does not change the robot's work start position, but controls the movement of the robot body so that the speed component of the workpiece movement direction at the work point changes in proportion to the conveyor speed. Met.

In other words, in the case of painting work, the speed component in the moving direction of the paint can attached to the wrist of the robot body or the workpiece at the target position (work point) is changed depending on the speed of the conveyor. Even if the speed changes, the work will always start from the time the workpiece moves to the same position on the conveyor (
(paint spraying).

``Problem to be solved by the invention'' For this reason, when the conveyor speed changes, the robot, 1.
Even though the required range of motion for the robot body is smaller than its maximum range of motion, the required posture of the robot body sometimes deviates from the range of motion, resulting in an abnormal stop.

For example, first paint the downstream side of the workpiece conveyor,
Next, if you are instructed to paint the surface of the workpiece on the upstream side of the conveyor, the slower the conveyor speed is than at the time of teaching, the faster the paint gun will be applied when painting the surface on the upstream side than at the time of teaching. Furthermore, the robot must be located on the first stream side of the conveyor, and the robot body must extend its arm further upstream than during teaching. For this reason, if the conveyor synchronization function was used to operate the robot and the conveyor speed was slowed down, the arm of the robot would be commanded to move beyond the allowable rotation angle, resulting in an abnormal stop. .

In other words, the robot body or the operating range will be biased toward the first flow side, and the conveyor linkage will be biased toward the 1st flow side. Occasionally, an inconvenient situation occurred where work could not be completed.

The present invention was made in view of the above-mentioned conventional problems, and even if the speed of the conveyor changes, if the movement range required of the robot body is smaller than its maximum movement range, the same teaching program can be used. The aim is to provide industrial robots that can continue.

"Means for Solving the Problems" The industrial robot of the present invention is an industrial robot that has a function in which the robot body synchronizes with the movement of the conveyor that transports the work and works on the work that is transported by the conveyor. Then, when the speed of the conveyor changes, the robot body starts working so that it shifts to the center position of the range in which the workpiece moves while the robot body is working, or to the center of the co-movement range of the robot body. It is characterized by being equipped with a control device that changes the position of the workpiece conveyor.

[Function] With the industrial robot of the present invention, when the speed of the conveyor changes, the robot is shifted to the center of the maximum operating range of the main body for work. Therefore, if the movement range required of the robot body after the speed change of the conveyor is smaller than its maximum movement range, the work can be continued using the same teaching program without exceeding the movement range.

``Example'' An example of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a diagram showing the configuration of a robot system using the industrial robot of the present invention.

This robot system has an industrial robot consisting of a robot body 2 disposed near a workpiece conveyor 4 and a control device 1 that controls the robot body 2, and also controls the speed of the conveyor 4. a speed detector 3 that detects and outputs a signal according to the speed to the control device 1; a position detector (path shown) that detects the position of the work on the conveyor 4 and outputs the signal to the control device 1; It is equipped with the following.

The robot main body 2 is, for example, a multi-joint type equipped with a wrist mechanism, and is operated under the control of the control device 1, and works by moving a tool such as a painting gun attached to the wrist mechanism.

The control device 1 is of a teaching/reproduction type that operates the robot main body 2 based on program data created corresponding to a workpiece, and the program data is stored in advance.

In addition, this control device 1 has a conveyor synchronization function, and when operating this function to operate the robot body,
When the speed of the conveyor 4 changes, it operates based on the flowchart shown in FIG. It has the function of

For example, when the robot body 2 is painting workpieces one after another that are being conveyed in synchronization with the conveyor 4, which is operating at a maximum speed of H, the conveyor speed is H.
c, the control device 1 performs the following steps 81 to S as shown in flowchart 1 in FIG.
Perform the process in step 5. Note that, as shown in FIG. 2, before the conveyor speed changes, the robot main body 2
Assume that the work starts when the work reaches point AA of ``-'' and ends when the work reaches point B of conveyor 4''.

[Step Sll Variation value of speed of conveyor 4 E = l-1c/H,,
, X are calculated and the process proceeds to step S2.

[Step S2] Coordinate P of the work start point A in the workpiece transport direction. and the coordinates P1 of the end point B. The coordinate P of the center (center position) θ of the movable range of the robot main body 2 in the transport direction of the workpiece is calculated as the median value of , and the process proceeds to step S3.

[Step S3] Workpiece movement distance before conveyor speed change (robot body 2
Distance that the workpiece moves while working) L=Pゎ−
P, , is calculated, and the process proceeds to step S4.

[Step S4 Workpiece movement distance L' after conveyor speed changes
-L-E is calculated and the process proceeds to step S5.

[Step S5] Coordinate p of the position A' of the workpiece on the conveyor 4 when the robot main body 2 starts work after the conveyor speed has changed.
Set '6 to P', =P, -L'/2, and complete the work.

According to the above operation of the control device 1, the work start position A' of the robot body 2 after the conveyor speed change is as shown in FIG. 2, and the work end position is the position indicated by the symbol Brr. Become.

That is, conventionally, when the conveyor speed decreases, -8 = The work start position of the robot body 2 after the conveyor speed change remains at position A shown in FIG. 2, and the work end position is at the position indicated by the symbol B'. As a result, the operating range of the robot body will be biased against its movable range. However, according to the industrial Kawaguchi bot of this embodiment, even if the speed of the conveyor 4 changes, the position where the robot body 2 operates is always shifted so as not to be biased toward the center of its movable range.

Therefore, if the movement range required of the robot body after the conveyor speed changes is smaller than its maximum movement range,
With the same teaching program, work can be continued without exceeding the operating range.

In particular, if the conveyor 4 is always operated according to the taught program while operating at its maximum speed, the movement range required of the robot body after the conveyor speed changes will always be smaller than the maximum movement range. , the work can definitely continue using the same teaching program.

Therefore, according to the industrial robot of this embodiment, the operating range of the robot body can be used effectively, the robot can be made smaller, and the number of teaching steps can be reduced. Furthermore, since abnormal stoppage due to exceeding the operating range is prevented, stable operation of the coating line is possible.

"Effects of the Invention" According to the industrial robot of the present invention, the robot body is shifted to the operating position or to the center of its movable range in response to changes in the speed of the conveyor, so even if the speed of the conveyor changes. If the movement range required of the robot body after that is smaller than its maximum movement range, the same teaching program will not exceed the movement range (the work can continue).

Therefore, the operating range of the robot body can be used effectively, the robot can be made smaller, and the number of teaching steps can be reduced. Furthermore, since it is possible to prevent abnormal stoppages due to exceeding the operating range, this has the effect of ensuring stable operation of the work line.

[Brief explanation of the drawing]

FIGS. 1 to 3 are diagrams showing an embodiment of the present invention,
Fig. 1 is a diagram showing the overall configuration of a robot system using the industrial robot of the present invention, Fig. 2 is a plan view for explaining the operation of the industrial robot of the invention, and Fig. 3 is the operation of the control device. It is a flowchart figure which shows. 1...Control device, 2...Robot body, 4...
Conveyor.

Claims (1)

[Scope of Claims] An industrial robot whose robot body has the function of working on a workpiece conveyed by a conveyor while synchronizing with the movement of a conveyor conveying the workpiece, and when the speed of the conveyor changes, the A control device that changes the position of the workpiece on the conveyor when the robot body starts work so that the center position of the range in which the workpiece moves during the work of the robot body is shifted to the center of the movable range of the robot body. An industrial robot characterized by: