JPS60156107A - Track correcting method of robot hand - Google Patents

Abstract

PURPOSE:To improve linear track accuracy and constant speed properties by obtaining a feedback gain based on output data of a position detector of an actuator. CONSTITUTION:A processor 1 of a track correction controller of a robot hand executes a management of a memory 3, etc. through various operation controls and a bus 2. In this state, in accordance with an instruction from a teaching box 8, four proportional coefficients in the memory 3 are initialized to a small value, and in accordance with program data, a playback operation by a linear path is executed. In this case, an output value of a displacement detector of an actuator of each sampling time is read, and stored as track data in the memory 3. Also, after the playback, the position of the head is calculated based on said stored data, and the distance between its position and theoretical track is calculated and stored in the same way. The same operation is repeated by changing said proportional coefficient, and an optimum value of each coefficient is determined.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a trajectory correction control device for a robot node, and particularly to a device for generating path interpolation data suitable for improving linear trajectory accuracy and maintaining constant speed. The present invention relates to a trajectory correction method for improving trajectory accuracy by performing preprocessing.

[Background of the invention]

As a linear trajectory control method using speed control, the applicant improves linear trajectory accuracy by feeding back the position deviation and speed deviation of the robot hand from a specified linear trajectory to the speed command value button at the next sampling time. We are developing a method to do so. At this time, the feedback is an amount proportional to 1 position deviation, an amount proportional to the accumulation of 1 position deviation,
The acid is proportional to the speed deviation in the constant speed command range on a straight line, and the amount proportional to the accumulated amount of this speed deviation is added to it.

At each sampling time, 4 m to determine these four proportional quantities.
It is not possible to obtain high linear trajectory accuracy unless the proportionality coefficient of is determined to an optimal value. However, the problem remains that the optimal values of these proportional coefficients vary each time the moving distance of the robot hand, the designated moving speed, and the position and orientation of the moving hand change. Therefore, it is difficult to set the value of the proportionality coefficient so that the linear trajectory accuracy is maximized during the playback operation.

[Purpose of the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for determining the optimum value of the proportionality coefficient to obtain the highest linear trajectory accuracy during sea playback operations without the difficulty in setting the value of such a proportionality coefficient.

[Summary of the Invention] A feature of the present invention is that the position deviation from the trajectory and the speed deviation from the specified speed are returned to the speed command value of the robot node to improve trajectory accuracy and constant speed. The point is that the optimum value is obtained based on the output data of the actuator's position detector.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 3. Figure 1 shows the measured data of the relationship between the proportionality coefficient value and the linear trajectory accuracy when the robot is taught two S points and then is made to perform a playback operation to connect these two points with a straight line. As shown, the horizontal axis is time, and the vertical axis is the positional deviation of the actual trajectory from the planned straight trajectory.

The robot used to obtain the same data had an upper arm length of 800 mm.
mm5 Articulated 5 degrees of freedom robot with forearm length 600 mm, sampling time 55 m1, movement command speed 100 m
In the case of m/ll, the velocity pattern is a trapezoid with constant acceleration.

The changed proportional coefficient is a coefficient of a term in which the current positional deviation is proportional to and fed back at the next sampling time, and corresponds to a proportional compensation term in PID control.

The other three types of proportionality coefficients are set to zero. In FIG. 1, this proportionality coefficient is set as b. When the proportionality coefficient k is small (k=4), the position difference becomes as shown in FIG. 1(a).

When the proportionality coefficient is 24, the situation is as shown in FIG. 1(b), and the one-position deviation is reduced to 115 phase degrees as in the case of FIG. 1(a). Furthermore, when the proportional coefficient = 28, Fig. 1 (a) V
As shown in C, the 1-proportional compensation amount is excessive, which causes a large oscillation and the positional deviation becomes large again.

1″ (″) ~ 1°)′″′” [ml! (')ilJt1
61 The vertical axis button shows the average positional deviation in one sampling, which is calculated by adding the busyness of each sampling time and dividing it by the number of sampling times.
FIG. 2 shows the proportionality coefficient on the horizontal axis. same·
As shown in the figure, when the proportional coefficient is increased and the noise is made, the absolute value of one positional deviation gradually decreases, and b<<, but the positional deviation conversely increases from a predetermined position.

That is, it forms a downward (-@)K convex curve. Similar results can be obtained for the other five types of proportionality coefficients. Therefore, in order to find the value of the proportionality coefficient that minimizes the 1-position deviation, it is necessary to gradually increase the proportionality coefficient from zero and find the point where the monotonous decrease in the 1-position deviation changes to a sharp increase in the single sea bream. The value of the proportionality coefficient obtained in this way will be referred to as the optimal value of the proportionality coefficient.

By the way, after finding the optimal value for a certain proportionality coefficient.

If the values of other proportionality coefficients are varied, the optimal value of the proportionality coefficient that has already been determined will vary slightly. Therefore, if the optimum values of the four types of proportionality coefficients are determined in order, and finally, the same operation is repeated again in the vicinity of those R optimum values.

The true optimal value is true.

Therefore, in order to find the optimal values of the four types of proportionality coefficients when playing back in a straight line between two specific points, it is necessary to have a first-order device.

That is, the robot hand button gray pack operation command is given while the four proportional coefficients are set arbitrarily.

Measure the positional deviation between the planned trajectory and the actually moved trajectory at each sampling time during playback operation, calculate the sum of the absolute values of the positional deviation, and compare it with the values of other proportional coefficients. All that is required is a device that compares the sum of the absolute values of the positional deviations, searches for an optimal value based on the graph of FIG. 2, and stores the obtained optimal value in a memory.

FIG. 3 is a concrete block configuration diagram for implementing the present invention, in which 1 indicates a processor, and a memory 3. Table 49 multiplier divider 5° Output port door, input port door, interface with teaching box 8. Output Portro.

The input port door forms an input/output section between the robot body 9 and the bus 2.

Processor 1#'i various calculation controls and memory via bus 5. Table 49 Multiply Divider 5. It manages the output ports, input ports, and teaching box 8. The memory stores arithmetic control programs and various data. The table is a data table that stores trigonometric functions-1 inverse trigonometric functions and the like. Further, the 1 multiplier/divider 5 is hardware dedicated to multiplication/division. The teaching box 8 is a console for man-machine interface during teaching. The reason for the robot drive system instructed by the teaching box 8 is that the teaching data obtained from the sensor is stored in the memory 3.

According to the same circuit configuration, first, four proportional coefficients in the memory 3 are initialized to small values in response to an instruction from the teaching box 8. Next, a playback operation along a straight path is performed according to the program data stored in the memory 3. At this time, the value of the displacement detector (not shown) of the actuator at each sampling time is read and stored in the memory 3 as robot trajectory data. After playback ends.

The position of the hand in space is calculated based on the robot's trajectory data stored in the memory 3, the distance between this position and the theoretical trajectory during playback is calculated, and the absolute value of this value is calculated for each sampling. and stores the result in memory 3.

Next, double the value of any one of the four proportional coefficients, perform the same operation as above, and compare the sum of the obtained absolute values with the value stored in the memory 3. Perform the following tasks:

(1) If the previous value is larger, the value of the proportionality coefficient is further increased at equal intervals and the above operation is repeated.

(2) If the previous value is smaller, the intermediate value of the previous proportional coefficient values is set as the next proportional coefficient value, and the above operation is repeated.

(3) Set the intermediate value between the previous proportional coefficient value and the current proportional coefficient value as the next proportional coefficient value, and repeat the above operation. If the value is the same as the previous value, the value of the proportionality coefficient is set as the intermediate value between the previous value and this time, and this is determined as the optimal value of the proportionality coefficient.

Repeat the same operation until the optimum value of the other three proportional coefficients is determined, and then repeat the above procedure again based on this value and store this value in the memory 5 as the final optimum value of the proportional coefficient. 1. It can be extracted as one of the playback data between predetermined points as a proportional coefficient during normal playback.

By storing the optimal value of this proportional coefficient in the area of the playback command that requires high linear trajectory accuracy in the memory playback program, multiple playback operations with high linear trajectory accuracy can be performed. It becomes possible.

According to the above embodiments, 1. For example, when interpolating a linear path between two points in a three-dimensional space, a starting point and an ending point, at a specified speed, the accuracy is greatly improved, and in particular, the robot drive unit is driven according to a specified linear trajectory. It is effective when

〔Effect of the invention〕

As is clear from the above-mentioned embodiments, according to the present invention, linear trajectory accuracy is improved and constant velocity can be improved to the maximum capability of the robot controller, and this can be done automatically. , the efficiency of the drive section is improved.

[Brief explanation of drawings]

The attached drawings are diagrams for explaining the present invention. Figure 1 is an explanatory diagram showing the relationship between the magnitude of the proportionality coefficient and positional deviation for one playback operation, Figure 2 is an explanatory diagram of the relationship between the magnitude of the proportionality coefficient and positional deviation, and Figure 3 is an explanatory diagram of the relationship between the magnitude of the proportionality coefficient and positional deviation. 1 is a circuit block diagram showing a specific configuration of the present invention. FIG. 1...processor, 2...bus, 3...memory,
4...Table, 5...Multiplier/divider, 6...Output boat, 7...Input port 1.8...Teaching box, 9...Robot body. Fig. 2 and Ren-ii)°Li-type Confucianism and (,

Claims (1)

[Claims] The position deviation and speed deviation from the specified linear trajectory of the robot I/MIM are converted into the speed command value.
: In a trajectory correction device for a robot node that performs path interpolation, an amount proportional to the feedback position deviation 9 An amount proportional to the accumulated amount of position deviation, an amount proportional to speed deviation,
A trajectory correction method for a robot, characterized in that the optimum value of each proportionality coefficient of an amount proportional to the accumulated amount of speed deviation is obtained from data of position detection values directly connected to a robot drive section.