JP2505546B2 - Position Reproduction Control Method for Direct Teaching Robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a position reproduction control method for a direct teaching type robot which is applied to a robot, a manipulator, a machine tool, a transportation machine or the like.

<Prior Art> A position reproducing mechanism of a conventional direct teaching type robot stores CPU 8 for controlling the operation of a robot (not shown) and control information such as a teaching position of the robot as shown in FIG. 4, for example. The memory 9 and the actuator 11 that drives the robot axis 10 in response to a command from the CPU 8.

In the teaching position stored in the memory 9, for example, in a painting robot or the like, a teacher directly moves the robot axis 10, samples the route at constant or variable time intervals, and stores it as a teaching position. There is.

When the robot reproduces the teaching position, the CPU 8 calculates a control signal for the actuator 11 from the position already taught from the memory 9 and the position information from the robot axis 10, and outputs the result to the actuator 11 as a command. As a result, the robot axis 10 moves accurately to the position taught in the memory 9.

<Problems to be Solved by the Invention> The above-described direct position teaching method for a robot has an advantage of being able to teach the teacher's skill as it is, but on the other hand, a movement such as a subtle hand shake that is not intended by the teacher is taught as it is. At the time of reproduction, as shown in FIG. 5, the teaching point P _i (i = 1,2, ...)
The actual route 6 connecting the two lines is deviated. As a result, there is a problem in use that the robot axis 10 makes an accurate movement with respect to the taught position, but has an unnatural movement with respect to the desired movement path 12.

In view of the above problems, the present invention is not a given teaching position itself when calculating the actual reproduction position of the robot axis, but a true target locus that is hidden by hand shake during direct teaching. An object of the present invention is to provide a robot position reproduction control method that approximates a smooth path intended by a teacher.

<Means for Solving the Problems> In order to achieve the above object, the present invention teaches a position reproduction control method for a direct teaching robot that reproduces a taught position so that the robot axis moves toward the taught position. The position P _i and k teaching positions P _j (j = i + 1, ..., i + k) in front of the position P _i ,
A specific weighting function K _j (j = i−m, ..., i, ..., i +) is applied to each of the rear m teaching positions P _j (j = i−m, ..., i−1).
k) is added and the average Is calculated, and this average P _i ′ is set as the reproduction position which is the movement target of the robot axis.

<Operation> According to the present invention, when the reproduction position P _i ′ corresponding to the teaching position P _i for moving the robot axis is calculated, the teaching position P _i , k teaching positions in front of the teaching position P and m teaching positions in the rear thereof are calculated. Teaching position is used, and teaching position (P _im , ..., P _i-1 , P _i , P _{i + 1} , ..., P _{i + k} )
On the other hand, the weighting function (K _im , ..., K _i-1 , K _i , K _{i + 1} , ..., K
_{i + K} ) is added, and the reproduction position P _i ′ is calculated as the average thereof. Therefore, the reproduction position P _i ′ is approximated to the desired operation path.
Can be calculated. Therefore, when reproducing the movement of the robot axis, it moves toward the reproduction position corrected by the calculation. As a result, it becomes possible to reproduce the movement of the robot axis along a smooth path close to the instructor's intention, that is, a true target locus hidden by camera shake during direct teaching.

<Example> An example of the present invention will be described below with reference to the drawings. still,
The fourth position reproduction mechanism of a direct teaching robot (not shown)
The same parts as those of the conventional technique shown in the drawing will be described with the same reference numerals.
As shown in FIG. 1, with respect to the teaching point P _i (i = 1, 2, ..., N),
A specific weighting function K _j (j = i−m, ..., i, ..., i + k) is determined, and using this weighting function K _j , the reproduction position P _i ′ of the teaching point P _i
Is calculated by the following formula.

In the above formula (1), the subscript j is a number indicating the position from the first teaching point, P _j is the j-th teaching position, and K _j is the teaching position.
The weight for P _j , m is the number of backward reference points of the i-th taught position P _i , and k is the number of forward reference points thereof.

The reference points k, m and the weighting function K _j are set in the memory 9 as data.

When the CPU 8 performs the calculation by reading the data from the memory 9, the i-th teaching position P _i to be reproduced from the memory 9 to the CPU 8 is input by the symbol 1 as shown in the flowchart of FIG. In symbol 2, the backward reference points P _im , ... P _{i-1 of} the teaching position P _i
Is input to CPU8.

For the forward reference points, k forward reference points P _{i + 1} , ...,
Input P _{i + k} to CPU8.

At symbol 3, the CPU 8 inputs the parameters of the weighting function preset in the memory 9 to the input forward reference point and backward reference point, and calculates the actual reproduction position P _i ′ according to the equation (1).

At reference numeral 4, the CPU 8 controls the actuator 11 toward the calculated reproduction position P _i ′, and the robot shaft 10 carries out a smooth reproduction operation.

In this case, the robot axis 10 will move to the teaching position as shown in FIG.
It is possible to correct the motion locus of the robot axis 10 near the instructor's intention by drawing a locus like the correction path 7 which is a smooth curve calculated by the equation (1) near the teaching path 6 connecting P _i .

Further, a setter such as a preset switch (not shown) capable of setting the number of reference points k and m and the weighting function K _j is provided outside the CPU 8.
May be connected to the CPU 8 so that it can be input.

<Effects of the Invention> The present invention, when the motion of the direct teaching robot is reproduced, calculates the reproduction position from the relationship between the teaching position before and after the teaching position, thereby hiding it at the teaching position due to camera shake during direct teaching. The true target trajectory that has been done, that is, the motion path that is similar to the path intended by the teacher can be inferred. As a result, the movement of the robot is smooth and natural, and the quality of painting and the like can be improved. Furthermore, the playback position and speed are also averaged,
Acceleration fluctuation is reduced and machine life is improved.

[Brief description of drawings]

1 to 3 show an embodiment of the present invention, FIG. 1 is a conceptual diagram, FIG. 2 is a flowchart diagram, FIG. 3 is a teaching path and an operation trajectory diagram by a position reproduction control method according to the present invention,
4 and 5 show an example of a conventional technique, FIG. 4 is a configuration diagram of a main part of a robot, and FIG. 5 is an operation locus diagram by a conventional reproduction position control method. In the figure, 6 is a teaching path, 7 is a correction path, and 10 is a robot axis.

Claims (1)

(57) [Claims] Claims: 1. A direct teaching robot position reproduction control method for reproducing a teach position so that a robot axis moves toward the teach position, wherein a teach position P _i and k teach positions P _{j in} front of the teach position P _i. (J = i + 1, ..., i + k), m rearward teaching positions P _j
For each of (j = i−m, ..., i−1), a specific weighting function
Add K _j (j = i−m, ..., i, ..., i + k) and average Is calculated, and this average P _i ′ is set as the reproduction position which is the movement target of the robot axis.