JPH0623927B2 - A safe operation control system for industrial robots with cooperative operation - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a safe driving control system for cooperatively operating a plurality of industrial robots.

[Prior Art] When performing welding work using an industrial robot, there were cases where two robots were used to shorten the welding work time. However, in this case, interference between the robots became a problem.

Conventionally, the solution to this kind of interference problem is to provide a fixed interference region or to control the robot via a complicated control device, which is difficult to handle.

For example, in Japanese Unexamined Patent Publication No. 53-78556, when one robot is in an overlapping work area, the other robot stops outside the area and the interference prevention signal from one robot disappears. It is known to start moving again at that time.

However, in these cases, when the overlapping work areas are wide, or when the takt time of the work handled by one robot requires a considerably long time, the waiting time of the other robot becomes long and the robot eventually operates. There was a problem that also adversely affected the rate.

Also known is a method of preventing interference between a plurality of robots via a complicated control device. However, since the robot is driven by a servo system, when transmitting the robot position information to the other robot as it is, the other party is configured by hardware, but the signal transmission method is difficult. , This signal also complicates the algorithm for processing by software.

In addition, when the position information of the robot is converted into a digital signal and transmitted, the number of signal lines increases. For example, when the position information is 16 bits, 32 signal lines are required between two robots. Further, in this case, the software needs to configure the entire robot system so that the position information of a plurality of robots can be placed on one coordinate system. In such a system, it is necessary to perform extremely complicated coordinate conversion. Comes out.

[Object of the Invention] An object of the present invention is to provide a simple means even when the plurality of industrial robots collaborate with each other, even within an interference region where they may interfere with each other when they operate. It is to prevent mutual robots from actually interfering with each other, to secure a sufficient safety, to have a wide movable region and to shorten the working time.

[Summary of the Invention] In order to achieve the above object, the present invention divides an interference region when a plurality of industrial robots perform cooperative operation into a plurality of partitions, and assigns partition codes to each partition, so that the robot itself can It calculates which partition code corresponds to the code of the position to which it should move, transmits this partition code to the other robot, and receives the partition code that was similarly calculated and transmitted from another robot It is configured to decide whether to move or not by matching with the section code of.

[Examples of the Invention] Examples of the present invention will be described below with reference to the drawings. In FIG. 1, Cartesian coordinate type robots 1 and 2 are provided facing each other.
Although not described in detail, each robot supports each work head so as to be movable in the X, Y, and Z directions in the three-dimensional space. The movable area of the work head is specified for each robot. Now, if the sliding ranges of the robot arm with respect to the base are represented by 3 and 4, respectively, they are in the horizontal plane (in the plane of FIG. 1). The movable region of the work head can be represented by regions 6 and 7 surrounded by a chain line.
The overlapping part of these areas is the area of cooperative operation, but the area 5 (hatched area) that interferes with each other is slightly wider than that. This is determined by the width of the robot arm and the mounting position of the processing tool.

Next, the interference prevention method in the present invention will be described in detail by taking the X direction as an example. Interference area 5 shown in FIG.
Is divided into a plurality of sections by a fixed pitch P defined by software. FIG. 2 shows a specific example thereof. These partitions are assigned partition numbers such as I-1 to I-5 and II-1 to II-5 corresponding to the robots 1 and 2, respectively. In this way, when the interference area 5 is divided at a constant pitch P, the robot 1 can separate the movable areas of the sections I-1, I-2, I-3, I-4, and I-5 when operating independently. The other robot 2 can take the movable areas of the sections II-1, II-2, II-3, II-4, II-5 when operating alone. In the mutual relation of these sections, for the section I-1 of the robot 1, the robot 2
Sections II-2 to II-5 are interference sections that actually interfere,
Only the section II-1 is a section in the movable area. Considering the case where the division of the interference area is divided with the division numbers as shown in FIG. 2, if this is generalized and expressed, the movable area of the robot 2 with respect to the division I-n of the robot 1 Section numbers II-n, II- (n-1) ,. Regarding the method of taking this area, the robot that first enters the area has a higher priority, and the movable area of the other robot is determined accordingly. This determination of the movable area can be performed in real time.

Another specific method for determining the partition number of the interference area will be described with reference to FIGS. 3 and 4.

Now, considering the sliding direction of the base of the robot, the pitch number obtained by dividing the command value of the robot measured from the origin position of the movable stroke of the robot by the pitch amount is obtained (FIG. 3).

This pitch number is adopted as the section number.

When the calculated result of the pitch number is larger than the maximum value of the number initially regarded as the interference region, it means that it is not the interference region.

That is, in the case of FIG. 3, 5 is the maximum value. The pitch number obtained in this way is constantly monitored while the robot is operating, and the command value is restricted so that it cannot enter the area where the other robot actually interferes.

Although details of a specific device for this control will not be described here, a flowchart of control by the device is shown in FIG.

First, the operation of the robot is started manually or automatically (step S1), and the position where the robot should move is calculated by performing a linear interpolation or the like on the teaching data (step S2).

The pitch number is determined by dividing the calculated internal operation command value by an appropriate predetermined pitch amount. At this time, the pitch amount is previously held as a constant and rewritable. The decimal point of the calculation result is truncated (step S3).

The pitch number thus obtained is transmitted to the opponent robot (step S4).

The pitch number of the player is compared with the maximum value of the interference number (5 in the case of FIG. 3) (step S5), and if the pitch number of the player is greater than the maximum value of the interference number,
Since the robot indicates that it is not in the interference area, the robot is moved to the position of the command value (step S6).

If the own pitch number is smaller than the maximum value of the interference numbers, the own pitch number is added to the pitch number of the opponent robot to judge whether or not they are in the mutual interference area (step S7). .

As a result of adding up the pitch numbers, when the value is less than or equal to the maximum value of the interference numbers plus 1 (for example, 6 in the case of FIG. 3), one is about to enter the area that actually interferes with the other. The robot that tries to enter the area that actually interferes is put on standby (step S8).

Also, as a result of adding up the pitch numbers, when the value exceeds the maximum value of the interference number plus 1, it is not trying to move to the actual interference area, so move the robot to the position indicated by the command value. Step (S9).

Next, it is determined whether or not the robot has reached the position designated by the command value (step S10), and if YES, the robot is positioned and work is started (step S1).
If 1), NO, the interpolation calculation is performed again (step S12).

This allows two robots to accomplish their work without interference.

Although the above description has been made especially for the robot of the orthogonal coordinate type, the idea is the same for other types of robots.

These other types of robots do not always perform orthogonal movements.Therefore, as a method of preventing interference, the path position of the robot to be moved is divided into a plurality of sections at a predetermined pitch amount, and the divided sections are handled. The external output signal composed of multiple pitch numbers assigned to the other robot is transmitted to the partner robot, and the external input signal similarly composed of multiple pitch numbers is received from the partner robot, and the robots move to each other. Check the positions and set an interlock so that they do not interfere with each other.

According to the above-described embodiment, the movable area between the opposing robots is not fixed, and the safe driving is performed not only in the one axis direction but also in the wide interference area by taking the interference area corresponding to each axis. You can

Since the interference area is divided into a plurality of pitches, the movable area can be made wider by appropriately selecting the number and length of the pitches. The pitches are not limited to equal pitches, but more effective movements are possible if the lengths are changed according to the movements of the robot.

Even during automatic operation, the movable area in the interference area changes in real time, so that there is an effect that the operation is not performed in a particularly limited area.

Furthermore, there is an effect that safe driving can be carried out by exchanging a few signals.

EFFECTS OF THE INVENTION According to the present invention, the inside of the interference area in which there is a possibility of interfering with each other when a plurality of industrial robots operates is divided into a plurality of sections, and the inside of the interference area in which the robot may interfere. However, since the section corresponding to the position to which these robots should move is monitored in real time and can be moved within the movable section area that does not actually cause interference, multiple industrial robots can be used. When the coordinated operation is performed, the movable range can be widened and the working time can be shortened.

[Brief description of drawings]

FIG. 1 is a plan view showing a cooperative operation when two robots are arranged facing each other, FIG. 2 is an enlarged explanatory view of an interference area in FIG. 1, and FIG. 3 is a general interference area. FIG. 4 is a conceptual diagram for explaining the partition calculation, and FIG. 4 is a control flowchart showing the operation of the control device of the present invention. 1, 2 ... Robot, 3, 4 ... Movable stroke, 5 ...
… Interference area, 6, 7… movable area.

Claims (5)

[Claims] 1. A safe operation control system for an industrial robot in which a plurality of robots have an interference area in which they interfere with each other and cooperate with each other. Corresponds to a partition code, and in each of the plurality of robots, the first step of calculating the partition code corresponding to the position to be moved, and the calculated partition code between the plurality of robots. A second step of mutually transmitting, a third step of judging whether or not there is an actual interference based on the partition code transmitted from another robot and the partition code of its own; A fourth step of moving the robot to the position to be moved if determined, and a robot that will move later if it is determined to interfere in the step. Safe driving control system of the industrial robot to the cooperative operation characterized by having a fifth step of waiting the door. 2. The safe driving of a cooperative industrial robot according to claim 1, characterized in that the movable area of each robot is divided by a predetermined pitch amount. control method. 3. The safe driving control system for an industrial robot having cooperative operation according to claim 2, wherein the pitch amounts are equal pitches. 4. The section code according to claim 3, wherein in the first step, a number obtained by dividing a robot command value by the pitch amount is cut off after the decimal point. A safe operation control system for the industrial robot that performs the described cooperative operation. 5. The safe driving control system for an industrial robot having cooperative operation according to claim 2, wherein the pitch amounts are unequal pitches.