JPH01173107A - Production of robot teaching program - Google Patents

Abstract

PURPOSE:To produce a robot teaching program which can be easily used at a site by mapping the prescribed points of plural plates onto a plane where a subject work is set and defining two points having the largest distance between them among those mapped prescribed points as the 1st and 2nd prescribed points of the two shift key points of a subject work. CONSTITUTION:The two-point shift extracting points are set for each plate defining a work when the key points of the two-point shift contained in a teaching program are set. Then those extracting points are mapped on a set plane of the work and two points having the largest distance between them are calculated among those mapped points. These two points are set to the teaching program as two key points of the two-point shift. Thus it is possible to minimize the influence of an error even though the error is the two points when the two points are taught to a controller against an actual work. Then the automatic operation is never interrupted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for creating a teaching program for an industrial robot having a two-point shift conversion function for teaching, playback, and evening play.

[Conventional technology] Industrial robots using the teaching/playpack method have data necessary for the work (motion trajectory, 1 work order, etc.).

The operator teaches the robot the work conditions (work conditions), and upon receiving a work command based on the data, the robot reproduces the specified work on the workpiece on the work stage as taught.

However, it is difficult to accurately match the coordinates of the taught workpiece with the coordinates of the workpiece carried and installed on the work stage.
For example, a one-turn table) is required. Therefore, instead of matching the workpiece to the teaching data, we use a separate teaching program to perform work on a member (hereinafter referred to as the workpiece).
The operator then arbitrarily selects and inputs two points that are easy to identify on the workpiece in order to convert one data of the teaching program.

Next, the work content is taught to the workpiece, the teaching program to the robot is edited, the data is set in the robot, and the teaching program is read. Note that there are cases where the teaching program is created by a robot.

Then, the operator inputs position data of two points on the actual workpiece, converts the workpiece locus data in the teaching program into locus data on the coordinates of the actual workpiece by two-point shift conversion, and performs automatic operation.

With the technologies described above, it has become possible to automate work on large members (workpieces), and it has become possible to improve work efficiency.

[Problem to be solved] However, in the conventional two-point shift conversion method, when teaching the control device two points on the actual workpiece, the operator simply selects an easily identifiable point on the workpiece. As a result, there was a large error between the position data after two-point shift conversion and the actual position of the workpiece, making it difficult to find the starting point for one task, resulting in temporary interruption of automatic operation and lowering one task efficiency.

The present invention provides a method for creating a teaching program for a robot, which minimizes the influence of errors when teaching two points on an actual workpiece to a control device and does not interrupt automatic operation. The purpose is to

[Means for Solving the Problems] In the robot teaching program creation method of the present invention, the target work in the teaching program is defined as a set of a plurality of predefined plates, and each of the plates has two A predetermined point for creating a representative point for a point shift is defined, and when creating a representative point for a two-point shift, the predetermined points of the plurality of plates constituting the target work are placed on the plane on which the target work is installed. After mapping, two points with the largest distance between the mapped predetermined points are set as the first predetermined point and the second predetermined point of the two-point shift representative points in the target workpiece. There is.

[Operation] When setting the representative point of the two-point shift included in the teaching program, set a two-point shift extraction point for each plate that defines the workpiece, map it to the plane where the workpiece is set, and use the mapped point. Calculate the two points with the longest distance between them,
These two points □ are set in the teaching program as two representative points of the two-point shift teaching.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings. FIG. 1 is a flowchart showing part of a method for creating a teaching program according to an embodiment.

In step 1, as shown in FIG. 4, the work shape data of the plates constituting the work is copied.

In step 2, as shown in FIG. 5, the plates of the copied workpiece shape data are taken out one by one, two-point shift extraction points are created for each plate, and the points are registered in the workpiece point data list.

In step 3, as shown in FIG. 6, the distance to each point in the point data list of the workpiece is calculated and the most distant points are listed. In this case, if there are multiple combinations instead of just one, they are also listed.

In step 4, it is determined whether there are multiple extracted combinations. If there are not more than one, go to step 6. If there are more than one, go to step 5 and select one from among the extracted combinations.
Let the operator choose one.

In step 6, the position data of the selected two points is registered as a two-point shift representative point.

The above is the procedure for determining the representative point for two-point shift conversion.

Here, details will be given of means for reducing the influence of a teaching error in two-point shift teaching on two-point shift conversion.

In a two-point shift, in order to minimize the influence of the teaching error of the two taught points on the two-point shift conversion, we first need to understand what kind of influence the teaching error actually has. need to be evaluated. There are many methods for this evaluation, but I simulated the following two-point shift transformation as a simple evaluation method.

(1) The actual workpiece matches the position set in the teaching program.

(2) In two-point teaching by two-point shift teaching, the error between the actual position and the taught position is the same at any point.

(3) The change in the teaching program before and after the 2-point shift is considered to be the influence of the teaching error.

Two-point shift conversion is usually realized using the following conversion formula.

Position data in the teaching program (X, Y).

The position data after the two-point shift conversion is (xyy), and the representative point of the two-point shift in the teaching program is (Xl).

y, ), (x,,y,), and the two actually taught points as (X
□*yt) e (Xis 3'z), the rotation center of the conversion source in two-point shift transformation is (Xl-Y3) -
The rotation center of the conversion destination in two-point shift conversion is (X,.

Assuming that it is determined as a row movement component.

θ=tan-”((yz-yt)/(xz-xz)
)-tan-'((Y, -yx)/(xi -xz)
)...(2) Here, in order to match the conditions of the previous simulation J, xi=X, +Δa, x, =X, +ΔC2yl =
Yt+Δt)t yi=Yz+Δd. Here, Δa, Δb, ΔC9Δd are teaching errors, and 1Δa
Assume that lFlΔb14IΔc141Δd1. Also,
For simplicity, X3=x, Y3=y.

Assuming that, the above equations (1) and (2) become as follows, where the influence of the teaching error is (X-x).

Y−y), but a method for reducing its influence can be found from the left side of equation (3).

One method is to reduce the absolute value of α.

From equation (4), (y * -'y 1) and <Xt-Xt>
The larger the absolute value of can be than the absolute value of (ΔC-Δa) or (Δd-Δb), the smaller α becomes.

Therefore, the larger the distance between the two representative points of the two-point shift is set, the smaller the influence of the teaching error will be. Therefore, the best way to set the representative point for the two-point shift is to probe and set the two most distant points on the workpiece.

Now, in the offline teaching device of this embodiment, a workpiece is defined as a collection of plates, which are the minimum constituent units. That is, as shown in FIG. 2, a workpiece is treated as a set of plates.The plate definition only needs to be registered once in the system, and then the registered plate is used to define the workpiece.

In the above-described plate definition, in addition to parameters such as the shape and designation of the position where the plate is installed, two-point shift extraction points are set. The dimensions of the plate, etc. are not defined at the time of system registration, but are structured so that they can be done when defining the work (parameters A4..., x8, etc. in Figure 2 are the dimensions of the plate. etc.).

Therefore, the two-point shift extraction points defined in the registered plate will be quoted.

There are no restrictions on setting this two-point shift extraction point, and it may be at the edge of the plate or at the center of the plate.

Normally, when teaching a robot a two-point shift, a position where it is easy to teach two points is selected.

An example is shown in FIG.

For example, in the case of a rectangular parallelepiped, there are four extraction points for two-point shift, each of which is an end of the figure. The reason why only 4 points were selected even though there were 8 end points is that only X and Y coordinates were required for the representative point of the 2-point shift, so points where X and Y were the same were excluded. On the other hand, in the case of a cylinder, the two-point shift extraction point is only one point at the center of the circle and does not include points on the circumference. This is because it is difficult to align points on the circumference.

Therefore, if a method is used in which two-point shift extraction points are generated for each plate on the workpiece, a list of the points is created, and the two points with the greatest distance are selected from the list, the operator can save two points. Point shift is easy to teach, and the two points that are farthest apart can be selected most quickly and easily.

You can get this benefit.

In addition to the method described above, to calculate the two points that are the most distant from each other, it is also possible to create a solid or surface model of the actual workpiece and calculate the distances from each point included in the workpiece to all other points. It can be done more accurately, but
The amount of calculation is enormous, and it takes a long time to calculate on a personal computer, making it impractical.

The teaching program creation method of this embodiment is configured as described above, and is carried out as follows.

First, the shape of the member (workpiece) to be taught for one operation is taught. As shown in FIG. 2, the workpiece is defined by considering it as a collection of plates, and parameters such as one dimension data are input.

In step 1 of FIG. 1, as shown in FIG. 4, workpiece shape data is copied from among the plates constituting the workpiece, excluding plates to be excluded when creating representative points for two-point shift.

This process is performed when the workpiece includes a plate that is to be excluded from the creation of the two-point shift representative point. This can be specified by the operator at that time, or it is also possible to decide in advance the plate type numbers to be excluded and have a list of excluded plates automatically created.

In step 2, as shown in FIG. 5, the plates of the copied workpiece shape data are taken out one by one, and the two-point shift extraction points for each plate are extracted and registered in the workpiece point data list.

For example, in Figure 5, the plate registered in the system as plate number 1 is set as a 2-point shift extraction point.
(Xzz*Yxi)* (Xzi*Yzi)* (Xx
a*Yza) - (XsieYz4) (7) A plate that has 4 points as candidates, those 4 points are copied and registered in the point data list, and is registered as plate number 2 in the system is used as a 2-point shift extraction point. , (XaL-Yzz)
* There are two points (Xsi, Yzz) as candidates, and those two points are copied and registered in the point data list.

In step 3, as shown in FIG. 6, the distance between each point (six points in the above example) in the point data list of the workpiece is calculated, and the most distant points are listed. In this case, if there are multiple combinations instead of just one, they are also listed.

In step 4, it is determined whether there are multiple extracted combinations. If there is more than one.

In step 5, the operator is made to select one of the extracted combinations.

This is a process that occurs when multiple combinations of the two points that are the most distant are extracted, but you can make this selection at this point, or you can specify it in advance so that it is automatically selected. You can.

In step 6, the position data of the selected two points is registered as a two-point shift representative point.

Hereafter, the same operations as in the conventional method are performed, ie.

Provide work instruction for workpieces.

Create a teaching program, edit the teaching program for the robot, and output it to, for example, a bubble memory cassette.

Load the teaching program 0 For example, set the above-mentioned bubble memory cassette in the robot and load the teaching program. Note that the teaching program may be created by a robot.

Input position data of two points on the actual workpiece using two-point shift teaching.

Two-point shift conversion is performed to convert workpiece trajectory data in the teaching program to trajectory data on the coordinates of the actual workpiece.

Carry out automatic operation.

Note that the creation of the two-point shift representative point may be executed at any time from after the shape of the workpiece is taught until the creation of the teaching program is completed.

As described in detail above, in the teaching program creation method of this embodiment, when creating the teaching program, consider the workpiece as a collection of plates, and sequentially input the data of the plates. Since the system automatically determines the two-point shift extraction point that is least susceptible to errors during teaching, even an unskilled operator can easily create a teaching program.

[·Effect of the invention] A method of creating a teaching program for a robot according to the present invention is as follows.

The target work in the teaching program is defined as a set of a plurality of predefined plates, each of which has a predetermined point defined in advance for creating a representative point for a two-point shift. When creating a representative point, after mapping predetermined points of the plurality of plates constituting the target work onto a plane on which the target work is installed, a distance between two points among these mapped predetermined points is the largest. Shift the two points on the target workpiece to the first of the representative points.
Since the predetermined point and the second predetermined point are used, (1) the two-point shift representative point can be created very quickly and simply.

(2) Since the two points on the workpiece that are the farthest apart and are the easiest to teach are selected as the two-point shift representative points, the two-point shift conversion error due to the two-point shift teaching error is reduced, and the automatic after two-point shift teaching is This eliminates the need for temporary interruptions during operation, which has the effect of improving work efficiency.

As a result, even an inexperienced person can easily create an excellent teaching program, and by applying this method, it is possible to obtain an excellent robot that is easy to use in the field.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing part of the teaching program creation in one embodiment, Fig. 2 is a diagram showing the structure and definition of a workpiece (workpiece shape data) in the method of the embodiment, and Fig. 3 is a diagram showing the method of the embodiment. A diagram showing the extraction points for two-point shift of the plate, Figure 4 is a diagram showing the creation of workpiece shape data for creating a two-point shift representative point using the method of the same embodiment, and Figure 5 is a diagram showing the extraction point of the plate for two-point shift using the method of the embodiment. FIG. 6 is a diagram illustrating creation of a point data list of a workpiece for creating representative points, and FIG. 6 is a diagram illustrating creation of a combination list of two points that are the most distant from each other in the same embodiment method. Figure 1 Figure 2 (a) (b) Figure 3 (H) Figure 4 Figure 5

Claims (1)

[Claims] (1) The coordinates of the first predetermined point and the second predetermined point of the actual workpiece carried onto the work stage are taught to the control device of the robot, and the control device teaches the coordinates of the target workpiece in the teaching program loaded in advance. The coordinates of the first predetermined point and the second predetermined point are compared with the coordinates of the first predetermined point and the second predetermined point of the actual workpiece, and the posture of the target workpiece in the teaching program is made to correspond to the posture of the actual workpiece. A method for creating a teaching program for a robot using a teaching/playback method in which work is started after performing a two-point shift to convert the coordinates into coordinates, the target workpiece in the teaching program being divided into a plurality of predefined plates. defined as a set, and each of the same plates has 2
A predetermined point for creating a representative point for a point shift is defined, and when creating a representative point for a two-point shift, the predetermined points of the plurality of plates constituting the target work are placed on the plane on which the target work is installed. After the mapping, two points with the largest distance between the two mapped predetermined points are set as the first predetermined point and the second predetermined point of the two-point shift representative points on the target workpiece. How to create a teaching program for a robot.