JPS63174889A - Method of controlling 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 Field of the Invention The present invention relates to a method for controlling a robot so that the robot can continue to operate completely from an intermediate stop.

Conventional technology Conventionally, inexpensive and easy-to-handle relative value encoders have often been used to detect the position of robots.
Continuing the operation again has been conventionally carried out under conditions where the power supply is not stopped during the stoppage. However, once the power is turned off while the robot is stopped, the arm position of the robot changes because a return-to-origin operation is required before continuing the operation. If the continuous motion is started at this point, the robot will start moving directly toward the target point of the continuous motion. FIG. 4 shows the above-mentioned example. A Cartesian coordinate type robot 1 and a chuck 2 equipped at the tip are driven by a numerical control device 3 to transfer a workpiece 4 from point 21 to point 22. At this time, in order to avoid the obstacle 6, the chuck 2 is controlled to pass through intermediate passing points Pbn and P2a in sequence. When this robot 1 is stopped midway at point P2a and continues its operation again, if the power is not stopped while the robot 1 is stopped, it will follow the path shown by the solid line, and if the power is stopped while it is stopped, it will take the path shown by the broken line. Move to the next 22 target points.

The above example uses a relative encoder for the arm position measurement device, but if an absolute encoder or resolver is used, an external force will be applied to the robot arm while it is stopped, and the state of the arm will change. Then, when the continuation motion is performed again, the robot starts moving directly from that state toward the target point of the continuation motion.

Problems to be Solved by the Invention However, in the above midway stop control method, the operation after the midway stop moves directly toward the target point of the continued operation regardless of whether or not the power supply is stopped. Even if there is an obstacle along the movement path, as shown by the broken line, the robot ignores this and moves. For this reason, there is a problem in that the robot itself, peripheral equipment, etc. are damaged, and complete continuous operation is impossible.

Therefore, the present invention is a control method that allows a robot to continue its complete operation regardless of whether or not the power is stopped after the robot is stopped midway.

Means for Solving the Problems In order to solve the above problems, the robot control method of the present invention updates and stores arm position information and external output signal information when the robot stops midway, and updates and stores the arm position information and external output signal information during the midway stop. Only when continuing operation is to be performed when there is a power outage, the memorized intermediate stop point is set as the operation target point after the return-to-origin operation, and the preset absolute avoidance point is set. This is a control method in which, after moving through the area, the external output signal is returned to the stored state and the operation is continued.

Operation The present invention uses the above-mentioned means, so that when a robot using a relative value encoder is temporarily stopped and the power supply is temporarily stopped, the continuous operation is performed by first passing through the absolute withdrawal area after returning to the origin. , the robot moves to the midway stop position while avoiding obstacles, restores the state of the external output signal, and returns to the same state as at the time of midway stop, and then starts continued operation. Further, if the power supply is not stopped, there is no change in the state, so direct continuation operation is disclosed.

As a result, the robot can continue to operate completely without damaging itself or its peripheral equipment, regardless of whether or not the power supply is temporarily stopped while the robot is stopped midway.

EXAMPLE Hereinafter, a method of controlling a robot to return from a mid-stop stop according to an example of the present invention will be described with reference to the drawings.

FIG. 1 is a flowchart showing the main points of a method for controlling a robot to return from a halfway stop in an embodiment of the present invention.

FIG. 2 shows the configuration of a numerical control device and its peripheral equipment that make this control method possible. In Figure 2,
1 is an orthogonal coordinate robot, 6 is an arm position detector, 3
1 is a numerical control device, 7 is a central processing unit (hereinafter abbreviated as CPU), 8 is a storage device, and 9 is a robot drive control device.

Hereinafter, one embodiment will be described according to the flowchart of FIG. 1 while referring to FIG.

The CPU 7 inside the numerical control device 3, which received the midway stop signal in step 1, analyzes the signal and performs step 2.
Instructs the drive control device 9 to stop the robot 1. At this time, the CPU 7 stores the state of the arm at the time of stop in the storage device 8 from the position information obtained from the arm position detection device 6 in step 3. At the same time, in step 4, the state of the external output signal from the numerical control device 3 at the time of stopping is also stored in the storage device 8. Next, the CPU 7, which has received the activation signal again in step 6, determines from the state of the storage device 8 whether or not the power supply has been stopped at least once during the mid-stop (step 6). Based on this condition judgment, if the power supply is not stopped, the operation is immediately continued in step 10. In addition, when the power supply is temporarily stopped, the CPU 7
The drive control device 9 is instructed to return the robot 1 to its origin (step 7). After this, in step 8, the robot 1
The CPU 7 issues a command to the drive control device 9 so that the vehicle passes through the vehicle and moves to the intermediate stop position stored in step 3.

When the movement to the intermediate stop position is completed, in step 9,
CPU U7uRestores the state of the external output signal stored in step 4. After reproducing the halfway stopped state in this way, the continued operation is started in step 10.

FIG. 3 shows the movement of the arm tip of the robot 1 according to this embodiment. It can be seen that the trajectory according to the conventional control method shown by the broken line intersects with the obstacle 5, whereas the present embodiment shown by the thick solid line faithfully continues the operation from the intermediate stopping point.

As described above, according to this embodiment, even if the power supply is temporarily stopped during a mid-stop, the system returns from the home return position through the absolute retract area, returns to the mid-stop position, and reproduces the mid-stop state. Since continuous operation is performed, complete continuous operation can be performed without damage caused by obstacles or the like.

Effects of the Invention As described above, the present invention enables a robot that uses a relative value encoder to return from a home return position to a mid-stop position through an absolute avoidance area when the power supply is temporarily stopped during a mid-stop. However, by performing complete continuous motion, it is possible to perform continuous motion equivalent to or better than a robot using an absolute encoder or resolver while using a relative encoder. It is very safe because it is accessible. Since the absolute save area is set on the storage device, it is easy to change. Also, since it uses a relative encoder, it can be realized at low cost.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing an overview of the robot control method according to the first embodiment of the present invention, FIG. 2 is a block diagram of a system that enables the control method shown in FIG. 1, and FIG.
The figure is an explanatory diagram showing the movement of the robot according to the control method shown in FIG. 1, and FIG. 4 is an explanatory diagram showing the movement of the robot according to the conventional control method. 1...Robot, 3...Numerical control device, 6...Arm position detection device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Li

Claims (1)

[Claims] A control method for completely continuing operation of a robot from a state where the robot is stopped midway, comprising: (1) receiving a signal to stop the robot midway; (2) executing step (1) and stopping the robot; (3) storing the state of the external output signal when step (2) is executed; (4) receiving a signal to start continuous operation; , (5) determining whether the power has stopped after executing step (3) and before executing step 4; (6) determining whether the power has stopped after executing step (5); (7) If step 5 is executed and the power supply is stopped, a step of performing a home return operation; (8) After executing step (7), the numerical control device (9) After executing step (8), the state of the external output signal stored in step (3) is restored. step, (1
0) A method for controlling a robot, comprising the following steps: performing a continuous operation after executing step 9.