JPS63233406A - Posture controller for robot - Google Patents

Abstract

PURPOSE:To prevent a robot from generating partial abrasion due to work applying large load to the robot kept at a fixed posture by controlling the robot so that its different postures are equally divided while keeping a tool at the same posture. CONSTITUTION:A 1st teaching point data teached so that a prescribed working posture is kept on a prescribed working position are stored in a 1st data storing device. A 2nd teaching point data teached so that the position and the posture of a burr removing tool 11 are the same as that of the 1st teaching point data, but the postures of an upper arm 15, a fore arm 16, a wrist 18, etc., of the robot are different from that of the 1st teaching point data are stored in a 2nd data storage device. A working command means distributes working cycles respectively based on the 1st and 2nd teaching point data approximately equally and executes these distributed cycles.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a robot posture control device that takes into consideration the durability of the robot.

[Prior art]

2. Description of the Related Art Conventionally, there has been known a device that uses an articulated robot to perform deburring processing. In this deburring process, the robot is taught to take a working posture at a taught working position and then perform the deburring process. and,
The posture of the robot at the working position is always taught to be the same posture.

[Problems to be solved by the invention]

However, the robot receives a large reaction force during deburring processing, so if deburring is performed in the same posture all the time, loads and vibrations are always applied to the drive system such as gears, bearings, and shafts in the same direction, causing the load to deteriorate. Since the parts affected by the damage are noticeably worn out, the durability of the entire robot is dominated by the durability of the local parts, resulting in a problem of shortening the lifespan of the robot. The present invention was made to solve the above-mentioned problems, and its purpose is to prevent local wear on the robot during work that requires a large load in a fixed posture, and to improve the durability of the robot. It's about improving.

[Means to solve the problem]

The configuration of the invention for solving the above problems includes a first data storage device that stores first teaching point data regarding the position and orientation of each teaching point on the motion locus of the tool tip; At the teaching point, which is the working position of the tool,
a second data storage device storing second teaching point data in which the tool is taught the same attitude as the attitude determined by the first teaching point data, but the robot is taught a different attitude; The present invention further comprises work command means for distributing and executing a work cycle based on the first teaching point data and a work cycle based on the second teaching point data approximately equally in a plurality of work cycles. It is.

[Operation] First teaching point data for teaching the user to take a predetermined working posture at a predetermined working position is stored in the first data storage device. In addition, at a predetermined work position, the position and tool posture are the same as the posture according to the first teaching point data, but the posture of the robot such as the arm and wrist is taught to be different from the first teaching point data. Second teach point data is stored in a second data storage device. The work command means is the first
The work cycle based on the second teaching point data and the work cycle based on the second teaching point data are distributed and executed approximately equally. Therefore, the same work at a predetermined work position is performed by distributing it to different postures of the robot, so there is no need to apply a large load to the same posture many times.
This will improve the durability of the robot. If there are two or more teaching methods in which the tool posture is the same but the robot posture is different at a given work position, the postures are stored as third or more teaching point data, and the three or more taught teaching methods are The teaching point data may be divided into approximately equal parts.

【Example】

The present invention will be explained below based on specific examples. FIG. 1 is a mechanical diagram showing the mechanism of a six-axis articulated robot. 10 is a robot main body, a base 13 for fixing the main body 10 to the floor is provided, a column 12 is fixedly installed on the pace 13, and a body 14 is rotatably provided on the column 12. . The body 14 rotatably supports an upper arm 15,
The upper arm 15 rotatably supports the forearm 1641. body 14, upper arm 15,
The forearm 16 has servo motors Ml and M, respectively.
2. M3 (see Figure 2) rotates around axes a, b, and c. This rotation angle is determined by encoders El, E2. Detected by E3. A beam strike 17 is attached to the tip of the forearm 16.
A hand 18 is rotatably supported on the wrist 17 so as to be rotatable around the e-axis, and a tool stand 19 is rotatably supported on the hand 18 around the f-axis. It is pivoted. A deburring tool 11 is fixedly mounted on the tool stand 19. The d-axis, e-axis, and f-axis are servo motors M4, M5, and M.
6. FIG. 2 is a block diagram showing the electrical configuration of the robot posture control device. 2o is a central processing unit consisting of a microcomputer and the like. The central processing unit 20 is connected to a memory 25 and a control panel 26 for instructing the servo CPUs 22a to 22f1 to jog the servo motors, instructing teaching points, and the like. Servo motor M for driving each axis a-f attached to the robot
1 to M6 are driven by servo CPUs 22a to 22f, respectively. Each of the servo CPUs 22a to 22f receives output angle data θ1 to θ6 output from the central processing unit 20 and an encoder E1 connected to the servo motors M1 to M6.
The deviation between the outputs α1 to α6 of ~E6 is calculated, and each servo motor M is operated at a speed according to the magnitude of the calculated deviation.
It operates to rotate 1 to M6. The memory 25 is provided with a PDA area in which a program for operating the robot according to teaching point data is stored and a storage area PA in which teaching point data representing the position and orientation of the deburring tool 11 is stored, and the teaching mode is set in the memory 25. , position data and posture data at a plurality of teaching points are stored. Further, the deburring tool 1 is driven by a tool drive circuit 23. Next, the operation of the present device will be explained with reference to the flowcharts in FIGS. 3 to 5 and the diagram showing the posture of the robot in FIG. 6. First, a method for creating the first teaching point data will be explained. In step 100, the teaching point number I is set to an initial value of 1, and in the next step 102, the position and orientation of the tip of the tool are manually controlled. And step 104
In step 102, it is determined whether or not to teach the position and posture at that time based on the operator's instructions.
The position and orientation of the tool are controlled. Also,
If you want to teach the position and posture at that time, step 10
6, and set the tool tip position and tool posture at that time to the first
is stored as teaching point data OA(+). Then, in step 108, it is determined whether or not the teaching of all routes has been completed. If the teaching has not been completed, the process moves to step 110, where the teaching point number I is updated by 1, and step 102
The next point on the route is taught. Through such processing, first teaching point data is created in the RAM 25. For example, in FIG. 6(a), Pl, P2, and P3 are teaching points on the path, and the tool tip position and tool posture as shown are taught sequentially from Pl. P3 is the working position of the robot, and the deburring process is performed in that position. Further, when the deburring process for one workpiece is completed, the posture is controlled in the opposite direction to P3, P2, and Pl. In this way, teaching is performed at the same point on one round trip route, and those teaching point data are the first teaching point data 0A (1) to DA.
(5). Next, a method for creating the second teaching point data will be explained with reference to FIG. First, in step 200, the first teaching point number ■ and the second teaching point number J are initialized to 1. And step 2
In step 02, it is determined whether or not to teach at the same position and orientation as the first teaching point data, and when teaching at the same position and orientation, the process moves to step 214 and the teaching is performed at the same position and orientation. Specify the first teaching point number I to be used. Next, the first teaching point data IIA(1) specified in step 216
The position and posture are controlled by the robot, and the robot actually assumes that position and posture. Then, in step 218, the first
The teaching point data OA(+) is the second teaching point data DB
(J), the second teaching point number J is updated by 1 in step 220, and the process returns to step 202. Next, if it is determined in step 202 that teaching is not performed at the same position and orientation as the first teaching point data, the process proceeds to step 204, where the tool tip position and tool orientation are manually controlled. Then, in step 206, it is determined whether or not to teach the position and orientation. If not, the process returns to step 204 and manual control of the position and orientation is performed again. If it is determined in step 206 that the position and orientation are to be taught, the process moves to step 208 where the manually controlled tool tip position and tool orientation are stored in the second teaching point data DB (J). be remembered. Then, it is determined in step 210 whether or not all teaching has been completed, and if all teaching has not been completed, the process moves to step 212, where the second teaching point number J is updated by 1, and step 202 The teaching operation at the next teaching point is executed. In this way, when teaching the same position and orientation as the first teaching point data, the robot is automatically controlled to that position and orientation by specifying the first teaching point data, and then and posture are stored as second teaching point data, and on the other hand,
If you do not want to teach at the same position and orientation as the first teaching point data, have the user actually take the desired position and orientation using the manual, and then store that position and orientation as the second teaching point data. There is. For example, in FIG. 6(b), Ql, Q2, and Q3 are teaching points on the path, and tool positions and tool postures as shown are taught sequentially from Ql. Ql and Q3 are equal to Pl and P3 of the first teaching point, and Q
3 is the working position of the robot, and the deburring process is performed in that position. When the deburring process for one workpiece is completed, the posture is controlled in the opposite direction to Q3, Q2, and Ql, similarly to the first teaching point data. In this way, teaching is performed at the same points on the round-trip route, and those teaching point data are stored in the RAM 25 as second teaching point data D[1 (1) to Rollo (5).
is stored in area PA. Point 02 is a teaching point unique to the second teaching point data, and is a teaching point existing between Ql and Q3, which is taught so that the robot can take the posture shown in the drawing at work position Q3. That is, when the robot is sequentially controlled by linear interpolation according to the second teaching point data D[l (1) to DB(5), the posture of the robot changes as shown. Next, the working cycle of the robot will be explained with reference to FIG. In step 300, the number of operations K is initialized to 1, and in the next step 302, the teaching point number ■ is initialized to 1. Further, in step 304, it is determined whether the value of K is an odd number or an even number, and if it is an odd number, in step 306, the first teaching point data OA (1) to DA (n) are set to the teaching point data of the current work cycle. If the value of K is an even number, the second teaching point data D[
1(1)~DII(m) is the current teaching point data W(1)~
It is assumed to be W(n). Then, in step 310, the posture of the robot is controlled by linear interpolation using the current teaching point data 11(+) as teaching data of the target point. When the posture at one teaching point is achieved, it is determined in step 312 whether or not the teaching point is the final teaching point, and if it is not the final teaching point, the process moves to step 314 and it is determined whether the current controlled position is the working position. If it is not the working position, the process moves to step 316, where the teaching point number I is incremented by 1, and the process returns to step 310, where the position and orientation up to the next teaching point are determined in the same manner as in the process described above. control is performed. On the other hand, if the current controlled position is determined to be the working position in step 314, the process moves to step 318, where the deburring tool is driven, until it is determined that the deburring process is completed in step 320. , the deburring tool is driven. When the deburring process is completed, the process moves to step 316, where the taught point number I is incremented by 1, and the process returns to step 310, where the position and orientation of the next taught point are controlled. In this way, when the processing up to the final teaching point is completed, the determination in step 312 becomes YBS, and step 322
Then, it is determined whether all the work has been completed. If all the work has not been completed, the number of works K is updated by 1 in step 324, the process returns to step 302, and the processing of the next work cycle is repeated until it is determined in step 322 that all the work has been completed. After all, the posture of the robot is controlled as shown in FIG. 6(a) according to the first teaching point data when the number of operations K is an odd number, and as shown in FIG. 6(a) when the number of operations K is an even number. It is controlled as shown in FIG. 6(b) according to the data. Therefore, the posture of the robot when performing the deburring process alternates between the postures shown in FIGS. 6(a) and 6(b), and local wear of the robot is prevented. In addition, since linear interpolation is performed in the above embodiment, the tool tip position and tool posture at the teaching point are taught. Although the tool tip position and tool posture are the same at the common work position, the robot posture However, if linear interpolation is not performed, the directions may be taught using the angles of each control axis of the robot. In addition, although two types of teaching point data are created in the above embodiment, if there are two or more robot postures in which the tool tip position and tool posture are the same at the working position, two or more teaching point data are created. Then, teaching point data may be created in the same way, and the working posture at the working position may be changed approximately equally. For example, for the posture of FIG. 6(a), FIGS. 7(a) and (b)
) There are also changes in posture. The same applies to FIG. 6(b). Therefore, in the example shown in FIG. 6, there are four different postures for the same working position U. In this case, these four postures may be taken in order at the working position.

【Effect of the invention】

The present invention provides that the tool has the same posture in the working position of the tool, but the robot has different postures in accordance with the taught data, and the robot has different postures in the working position in multiple working cycles of the robot. Since the robot is controlled to be distributed evenly, a high load is prevented from always being applied to the robot in the same posture, and local wear and tear of the robot's shafts, bearings, etc. is prevented. Therefore, the durability of the robot is improved.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the mechanical configuration of a robot according to an embodiment. ′? FIG. 52 is a block diagram showing the electrical configuration of the attitude control device according to the embodiment. Figure 3, Figure 4, Figure 5
The figure is a flowchart showing the processing procedure of the CPU used in the attitude control device of the embodiment. FIGS. 6 and 7 are explanatory diagrams showing changes in the posture of the robot. 11 Deburring tool 12 Column 13・-Base
14 ″Body 15°゛Upper arm 16・°″
Forearm 17゛・°Wrist 18・Hand 1
9゛Tool stand 22゛Servo CPU 25...AM

Claims (1)

[Claims] (1) a first data storage device that stores first teaching point data regarding the position and orientation of each teaching point on the motion trajectory of the tool tip; and a teaching point that is the working position of the tool among the teaching points; , a second teaching point data that stores second teaching point data in which the tool is taught the same attitude as the attitude determined by the first teaching point data, but the robot is taught a different attitude.
The data storage device and the robot execute the work by dividing the work cycle based on the first teaching point data and the work cycle based on the second teaching point data into approximately equal parts in a large number of work cycles of the robot. 1. A robot attitude control device comprising: command means.