JPH01316185A - Path producing method for industrial robot - Google Patents

Abstract

PURPOSE:To facilitate the processing of a three dimensional position and a posture of a robot and reduce a computing quantity by performing a process to smooth an orthogonal data of a path interpolation unit after concluding an interpolation computing and before a coordinate transformation. CONSTITUTION:The smoothing process 27 of sequence of points obtained as a result of interpolation is performed per each component referring to a rectangular coordinate system. The date obtained in this way is generated as a command referring to the rectangular coordinate system, and a coordinate transformation processing 28 of this command value is performed so as to obtain a command 29 of a joint coordinate system. On the basis of this command 29, a position of a tool machine installed in a driving mechanism of an industrial robot traces a smooth track in an orthogonal space.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to control technology for industrial robots.

In particular, the present invention relates to a robot control method suitable for easily and smoothly controlling a robot.

[Conventional technology]

The conventional device is 1 Japan Society of Mechanical Engineers Transactions C, Volume 48, 43
No. 1 (PP990-997) (Showa 57-7), ``Route Compensation of Robot Hands 1, Method of Generating a Parabolic Trajectory by Linearly Interpolating Velocity Vector Components,'' or the 3rd International Symposium on Robotics Research (1985) (3r
dInternational Sya+posiuI
Ion Robotics Research (198
Trajectory generation described in 5))
Four mobile robot (Trajectory
Generation for Mobile Rob
ots) discusses a method of generating a trajectory with continuous acceleration changes using a clothoid curve.

Furthermore, a method to avoid sudden changes in direction at the tip of the wrist was introduced in Tokuko Sho 5.
It is shown in No. 1-34180.

[Problem to be solved by the invention]

In conventional technology, in order to improve the accuracy of the robot's path, the robot accelerates and decelerates at the joints of sections where the direction of movement changes discontinuously to prevent vibrations, but this increases the time required for the robot to move. . In addition, in an attempt to create essentially smooth trajectories, we generated trajectories with continuous velocity vectors and trajectories with continuous acceleration, but the teaching method required three or more points to determine the trajectory. There was a point that data was required and the calculations for determining the trajectory were complicated6.
An object of the present invention is to provide a robot that moves smoothly without deceleration, without requiring a large amount of teaching data to determine the trajectory, and in which the trajectory can be generated through easy calculations.

[Means to solve the problem]

The above object is achieved by smoothing the orthogonal data of the path interpolation unit after completion of interpolation calculation and before coordinate transformation.

[Operation] The smoothing filter that processes orthogonal data in the path interpolation section adds several adjacent points and takes the average.
In this way, the effect of the filter appears and the robot operates smoothly.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7. FIG. 5 is an overall equipment configuration diagram of this embodiment. 1 is a robot control device, which controls the body shown in FIG. 2 is the robot body, which performs work using six servo motors. 3 is a wire. 5 is a welding torch. 6 is a work stand. 4 is a teach box, which is used to teach the robot's movements.

FIG. 2 is an internal block diagram of the hardware shown in FIG. 1.

The robot control device 1 has the following configuration. 7 is a CPU, which performs all controls related to the robot control device. 8 is a bubble memory 6 Bubble memory is a non-volatile memory in which data and programs that should not be lost when the power is cut off are written. 9 is R
AM, which stores programs and data executed by the CPU. Reference numeral 10 denotes a ROM, which stores a program that describes the procedure for the CPU to load a program from the bubble memory 8 to the RAM 50 when the power is turned on. 11 is an I10 control unit, and keyboard 1
4. It controls input/output between the CRT controller 15 and the teach box 4. 14 is a keyboard, which is attached to the top surface of the robot control device 1. 16 is C
It is an RT controller and displays various information on a CRT 16 attached to the top surface of the robot control device 1. 1
2 is a servo control section. The servo control section gives commands for the rotation of each motor to the servo amplifier section 13 based on commands from the CPU. The servo amplifier section 13 has six motors, M1 to M6.18, attached to the robot body 2.
23.

The program of the present invention is stored in the bubble memory 8, transferred to the RAM, and executed.

The present invention will be explained in detail below.

In an industrial robot, when performing path interpolation such as a straight line, the teaching point Pa at 24.25 in FIG.

Interpolation is performed from the orthogonal data of pb. As shown in the flowchart of FIG. become The smoothed x" (t) p y" (t) p z"(t)' is subjected to coordinate transformation 28, and the joint data θi is sent to the servo system as a command value 2.
Output as 9. The processing of the smoothing filter is as shown in the flowchart of FIG. Memorize the input data up to n times before and input the current data and a total of N times 30 = (
The average value 31 of the data of n+1) is output. To give an example in two dimensions, on the xy plane (0, 10) (0, 0) (
10,0) as the teaching point, if smoothing filter processing is not performed, (X (i) Y (i)
) The robot's hand moves on the data shown by , and it becomes a graph as shown by 32 "input" in FIG.

However, when smoothing filter processing is performed, when the number of stages N = 4, the average of 4 times of 3 times previous data, 2 @ next data, previous data, and current data is calculated using the following formula (R = i -N+ 1) However, when R<O, X (0)=O, Y (0)=1
0, it can be determined by X (R) = X (0) Y (R) = Y (0), and the result is
(t), Y” (t), as shown, and the eighth
The curve 33 "output" in the figure is the trajectory of the robot after smoothing filter processing.

By performing the above-mentioned processing after the interpolation processing is completed and before the coordinate transformation, it is possible to check the motion range at the orthogonal level, and furthermore, there is an effect that the smoothing processing can be performed with a small amount of calculation.

In the embodiments described above, a case has been described in which a weighted average of consecutive interpolation points is calculated as the smoothing process, but a method of calculating a geometric average or a harmonic average can also be adopted.

〔Effect of the invention〕

According to the present invention, since smoothing processing is performed before coordinate transformation, it is easy to manage the three-dimensional position and posture of the robot, and geometric calculations, etc. are not required to generate a smoothed trajectory. ,
This has the effect of requiring less calculation.

[Brief explanation of the drawing]

Fig. 1 is a flowchart of the present invention Fig. 2 is a hardware block diagram Fig. 3 is an overall configuration diagram of an embodiment of the invention Fig. 4 is the robot body Fig. 5 is an overall equipment configuration diagram of the system Flowchart of smoothing filter processing FIG. 7 is a smoothing processing result table FIG. 8 is a smoothing processing result graph 26...Interpolation processing, 27...Smoothing filter processing, 2
Figure 8 4 The present invention
2 Figure $ 3 Figure Lohot Luli Control I Setting Sutra P - Alignment Ruler 2) Smoothing Process (Change Data No. 4 Lohot Hontaira 512I Fig. 6 Circle J Ossification) δ Luxury 1; stone stone 4 flow night (2nd order 0 small 1)

Claims (1)

[Claims] 1. In an industrial robot with a drive mechanism composed of multiple degrees of freedom, the movement is controlled by giving representative points on the trajectory to be passed and interpolating between these points with straight lines, arcs, etc. in an orthogonal system. , perform smoothing processing for each component regarding the orthogonal coordinate system on the point sequence obtained as the interpolation result,
The data obtained by this is generated as a command regarding the orthogonal coordinate system, and by performing coordinate transformation processing on this command value, the joint coordinate system command is obtained, and the position of the work tool attached to the above mechanism is orthogonally determined. A path generation method for an industrial robot characterized by controlling the robot so that it follows a smooth trajectory in space.