JPS63254502A - Robot controller - Google Patents

Abstract

PURPOSE:To perform the locus control of a robot with high accuracy and high efficiency by pre-reading and storing the dot train data, discriminating said stored data from the used for execution of the robot locus control, and deciding and reading out successively the desired data. CONSTITUTION:A buffer memory BM stores the dot train data which is pre-read out of a robot command data memory RCDM connected to a processor RPU. The memory BM receives the cyclic accesses from the processor RPU and has the pointers of a tab parts which are sequentially rewritten. In other words, pointers CBP and UBP are always monitored by the RPU so that the dot train data stored in a data part can be discriminated from the dot train data used for the robot locus control of the RPU. Then the dot train data needed for the locus control are successively read out after a block of the data part storing said dot train data is identified with reference to a calculation block pointer CBP.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a robot control device for controlling the trajectory of a teach-and-play industrial robot.

(Prior art) In order for an industrial robot to function in accordance with a required purpose, it is necessary to have a teaching function that teaches the industrial robot the work in advance, a memory function that stores work data, and a robot hand based on this data. A regeneration function that operates while controlling the trajectory at a predetermined speed is required. In these current teach-and-play robots, the conventional calculation method for trajectory control is to teach the positions of #, a scattered series of points on one path in advance, and to Command data is created, the robot command data is read out one block at a time during playback, and the hand is moved based on the data.

In this case, in a robot control device that stores data on the movement target position as each axis value of art, trajectory control is executed in the following procedure as shown in FIG.

That is, in step a, the values of the starting point and ending point (and transit points) of the trajectory control are read from the data memory, and each value is converted from each axis inclination to an orthogonal coordinate value at the TCP (tool center point). In step b, coordinate values of dividing points on the trajectory are calculated using the converted orthogonal coordinate values.

In step C, each axis inclination is determined by inverse transformation from the orthogonal coordinate values of the dividing points. In step d, the TCP drives the motor of each axis to reach the individual split points. and,
In step e, while the hand is moving to a predetermined operating point, the calculations in steps b and c regarding the next division point are executed, and when the output of the movement command regarding the currently targeted division point is completed, the next division point is Outputs a movement command to the dividing point.

(Problem to be Solved by the Invention) Generally, when controlling the trajectory of a multi-axis robot, in order to improve the accuracy of movement command output, it is necessary to increase the number of division points and shorten the interpolation interval. In this robot control device, the writing of distribution pulses to the servo circuit (servo LSI) of each axis and calculations regarding dividing points are performed in parallel, so in order to increase the number of dividing points, the calculation processing in the CPU is required. In addition, at the start of trajectory control, time is required to read and convert the data in step a from the memory, and in order to smoothly transition to trajectory control. However, there was a problem in that the accuracy of trajectory control was restricted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a robot control device that accurately and efficiently controls the trajectory of a robot.

(Means for Solving the Problems) A robot control device of the present invention is a robot control device that performs trajectory control of a robot based on discrete point sequence data on a taught path. a storage means for storing the data, an identification means for identifying data stored in the storage means and data used for execution of the trajectory control, and an identification means for determining data necessary for execution and storing the data in the storage means; and an output means for sequentially reading data from the means.

(Operation) That is, in the robot control device of the present invention, the robot motion command program is read in advance before its execution, and the corresponding point sequence data is selected based on the trajectory control command included therein, and the data necessary for trajectory control is selected. The data required for trajectory control can be read out at high speed by performing processing such as coordinate transformation and storing the data in a buffer memory, etc., and identifying the data portion when the program is executed.

(Example) Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a robot control device of the present invention. Robot command data memory RODI
The controller is connected to a processing unit RPU, in which a series of robot command data has already been stored through teaching operations. This robot command data includes a group of position data that expresses a discrete point sequence on the path as the tilt of each axis of the robot,
It consists of a block number that identifies the execution order of each data group. The teaching pendant TB has a mode select switch, and can select between a playback mode and a teaching mode. The read-only memory ROM stores a control program that controls the processing bag 2JRPU, and when the playback mode is selected, the read-only memory ROM stores a control program that controls the processing bag 2JRPU.
It reads out data one block at a time and controls calculation processing such as converting the tilt of each axis into orthogonal coordinate values of the robot's TCP.

The figure shows the servo motor SN for only one axis, but the servo circuit for each axis includes a pulse distributor PDC that outputs distributed pulses from the incremental amount for each axis calculated by the processing device RPυ, and a servo motor SN for each axis. It consists of a servo unit (servo unit) SVU that controls the servo motor, a pulse generator PG that feeds back rotation signals from the servo motor SN, etc., and a processing unit RPU calculates the remaining movement amount and current position for each axis each time the hand moves a specified distance. and stores it in the data memory DM.

B is a buffer memory having a block configuration as shown in FIG. 2, which is connected to the processing unit RPU and stores point sequence data read in advance from the robot command data memory RC:DM. This buffer memory BM is configured as a memory of multiple blocks, each block consisting of a tab section and a data section.The tab section stores the block number in the program, and the data section is converted into orthogonal coordinate values. location data is stored. This buffer memory BM is cyclically accessed by the processing bag FI RPU,
The pointer in the tab section is rewritten one after another. In other words, it includes a calculate block pointer CBP indicating a corresponding block of point sequence data for which arithmetic processing has been completed according to the prefetched program, and a pointer UBP of the block used to execute the program, and these pointers CBP, U
By constantly monitoring BP with processing unit RPU,
The point sequence data stored in the data section and the point sequence data used for execution of trajectory control in the processing unit RPU can be distinguished.

In a robot control device configured in this way, the processing unit RPU performs multitasking to prefetch the program at the lowest level (idle task), and uses preparation code such as Got and GO2 to perform linear interpolation and internal interpolation. When there is a command for trajectory control, the corresponding point sequence data is retrieved from the data memory RC:DM,
The arithmetic processing in step a shown in FIG. 3 can be executed and stored in the buffer memory BH. This process can be executed seemingly all the time, so it can be executed by the processing device R.
Regardless of the processing capacity of the PU, the buffer memory BM
The interpolation accuracy can be increased as much as possible within the storage area of . As the program progresses and a block including a corresponding trajectory control command is executed, the calculate block pointer CBP is referred to and the point sequence data required for execution is stored. It is sufficient to identify the blocks in the data section and read them out sequentially.

In other words, there is no need for coordinate conversion processing at the start of trajectory control, and only calculations regarding the minute** point in the processing bag 21RPU are performed, so that the processing time becomes approximately constant.

In addition, when reading ahead, the processing of steps b and c shown in FIG. 3,
In other words, if the arithmetic processing related to the division points is executed in a similar idle task, the interpolation interval can be further shortened, and the trajectory control can be efficiently executed using the processing unit RPU with limited arithmetic capacity.

(Effects of the Invention) As described above, according to the present invention, the robot control device is capable of quickly reading out point sequence data necessary for robot trajectory control, and is effective in improving control accuracy. can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is an explanatory diagram showing an example of the configuration of a buffer memory, and FIG. 3 is an explanatory diagram showing a general trajectory control processing procedure. be. RPU...Processing unit, RC[1M-...Robot command data memory, BM...Buffer memory, TB...
Teaching operation panel.

Claims (2)

[Claims] (1) In a robot control device that controls the trajectory of a robot based on discrete point sequence data on a taught path, a storage means for pre-reading and storing the point sequence data;
an identification means for identifying data stored in the storage means and data used for execution of the trajectory control; and an output means for determining data required for execution by the identification means and sequentially reading out data from the storage means. A robot control device comprising: (2) The robot control device according to claim 1, wherein the storage means stores processed data regarding division points of trajectory control.