JP3166316B2 - Teaching and control method of playback type robot - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for teaching and controlling a playback type robot, and to shorten the teaching time.

[0002]

2. Description of the Related Art Playback type robots are one type of industrial robots. In the playback type robot, before the robot actually performs the work, the robot directly moves the robot with a control stick or the like to teach the work content, and then performs the work by reproducing the work content later.

[0003] Using a playback type robot, an operation of cutting a curved workpiece (hereinafter referred to as "work"), for example, a cylindrical plastic has been performed. In order to cut such a curved workpiece, an arc-shaped path must be taught. Therefore, at the time of teaching, the path is measured using a laser sensor provided at the hand of the robot, and teaching is performed. At the time of actual work, a cutting device (grinder, etc.) provided at the hand of the robot is moved along the teaching process. Cutting work is being performed.

In order to teach the arc-shaped path K for cutting the work 1 as shown in FIG. 7, conventionally, three-point teaching for storing three points A, B, and C is performed. Each point A,
The positions of B and C are the posture of the robot and the laser sensor 2
(See FIG. 8) from the surface of the work 1. At the time of cutting work, points A, B, C
Is interpolated by a curve and the grinder is moved along the arc-shaped path K.

[0005]

As described above, conventionally, in order to teach an arcuate path, three points must be measured and stored as teaching points, so that much time is required for teaching work. Was.

An object of the present invention is to provide a teaching and control method for a playback type robot, which has a small number of teaching points and a short teaching time in view of the above-mentioned prior art.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a playback type robot comprising: a real working machine and a distance sensor in a direction corresponding to the direction of the hand;
When the distance sensor is rotated within a predetermined first plane around the tip of the distance sensor as a rotation center, the posture in which the detection distance to the work surface detected by the distance sensor is minimized is defined as a first posture, Next, when the distance sensor is rotated around the tip of the distance sensor as a rotation center in a second plane including a straight line representing the direction of the distance sensor in the first posture and orthogonal to the first plane. When the position where the detection distance to the work surface detected by the sensor is the minimum, teach the intersection of the extension line of the distance sensor and the work surface as the start point, and from the data indicating the traveling direction of the hand and the work shape, Finds a calculation point located in the direction of travel on the work surface, and changes the posture so that the hand is always perpendicular to the work surface when the hand is moved along the path connecting the start point and the calculation point. Calculate the quantity and the hand While maintaining a posture in which the direction is perpendicular to the workpiece surface, performed by moving the hand portion along the path connecting the start point and the operation point, characterized in that the actual work by the actual working machine.

[0008]

When a start point is taught, a calculation point is obtained by calculation, and actual work is performed along a path connecting the start point and the calculation point.

[0009]

Embodiments of the present invention will be described below. The method according to the present embodiment is applied to a playback type robot 4 as shown in FIG. 1, and a laser sensor 2 and a grinder 3 are provided at a hand 4 a of the robot 4. The direction of the laser sensor 2 and the direction of the grinder 3 match the direction of the hand portion 4a. The laser sensor 2 measures the distance from the sensor tip to the work surface. The posture of the robot 4 is detected by a sensor (not shown). The distance data detected by the laser sensor 2 and the posture data detected by the robot sensor are sent to the control device 5.

The control unit 5 performs data processing described later to determine a movement path, and further controls the driving of the robot 4 so as to move the grinder 3 along the movement path.

Next, the teaching / control operation of the control device 5 will be described.
The description will be made mainly with reference to the flowchart of FIG.

In step 1 of FIG. 2, data such as the shape of the work is input to the control device 5. As shown in FIG. 3, when the work 1 has a cylindrical shape or the curved surface of the work has a shape obtained by extracting a part of the cylinder, the radius of curvature r and the thickness t are input.

In step 2, a start point P ₀ is generated.
The starting point P ₀ is determined as follows. First, as shown in FIG. 4 (plan view), the position of the tip of the laser sensor 2 is fixed, and the laser sensor 2 is rotated in a horizontal plane with the tip of the sensor 2 as the center of rotation. At this time, the position where the detection distance to the surface of the work 1 is the minimum is defined as a vertical posture in a horizontal plane. Next, as shown in FIG.
Is fixed, and the laser sensor 2 is rotated in a vertical plane around the tip of the sensor 2 as a rotation center. At this time, the position where the detection distance to the surface of the work 1 is the minimum is defined as a vertical posture in a vertical plane. Then, the posture in which the vertical posture is set in both the horizontal plane and the vertical plane is defined as a true vertical posture, and the intersection point between the extension of the laser sensor 2 and the work surface at this time is defined as a start point P.
_Set to ₀ . Also, the attitude of the robot 4 when the laser sensor 2 is in the true vertical attitude, that is, when the direction of the hand tip 4 of the robot is perpendicular to the work surface, is stored.

In step 3, the traveling direction of the hand portion 4a is specified. In the example of FIG. 3, a command is given to move horizontally along the circumferential direction of the work 1.

In step 4, a calculation point P ₁ located on the surface of the work 1 in the traveling direction is obtained by calculation, and the posture of the laser sensor 2 toward the calculation point P ₁ is determined.
A posture change control amount for obtaining a true vertical posture with respect to the surface of is obtained. That is, as shown in FIG. 6, the point P ₁ is located at a position shifted from the point P _{0 by} Δx in the X-axis direction and Δy in the Y-axis direction, and Δx and Δy are expressed by the following equations (1) and (2). Given by

[0016]

Δx = r (1−cosωt) (1) Δy = r sinωt (2) where ωt is an angle formed between the straight line P ₀ Q and the straight line P ₁ Q.

If the distance between the laser sensor 2 and the surface of the workpiece 1 is l, the attitude of the laser sensor 2 is such that the laser sensor 2 always faces the point Q on a circle having a radius r + 1 around the point Q. Rotate around point Q while maintaining the posture. Accordingly, the direction of the laser sensor 2, that is, the direction of the hand portion 4 a is always in a vertical posture with respect to the surface of the work 1.

The controller 5 calculates a path K ₀₁ (FIG. 3) by performing a curve interpolation between the taught P ₀ and the point P ₁ obtained by the calculation. In step 5, while moving along the hand portion 4a to the route K _01, the workpiece 1 by a grinder 3
Cut off. At this time, the moving speed of the hand portion 4a (the grinder 3) is determined by the thickness t of the work 1. That is, when t is large, the cutting depth is large,
Is decreased, and when t is small, the moving speed is increased. Further, when cutting with the grinder 3 while moving the hand portion 4a in this manner, the posture of the hand portion 4a is controlled so that the laser sensor 2 and the grinder 3 are always perpendicular to the surface of the work 1.

[0019] Once discontinue cutting Once progressed cut to P ₁ point, determined by calculation operation point P ₂ by the same as that determined the point P ₁ approach. And performing a cutting along the points P _1, P ₂ in the path K ₁₂ were curve interpolation. Thereafter, similarly, calculation points are successively obtained, and cutting is performed up to that calculation point.

In the above embodiment, cutting is performed by a grinder, but it goes without saying that the present invention can also be applied to cutting by a burner, a plasma torch, or the like.

[0021]

As described above in detail with reference to the embodiments, according to the present invention, if only one start point is designated, the operation points are successively obtained by calculation, and the start point is determined. Actual work is performed along the path connecting the points and the calculation points. As described above, in the present invention, only one teaching point is required, so that the teaching time can be shortened, the actual work can be performed immediately, and the efficiency is high.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a robot to which the present invention is applied.

FIG. 2 is a flowchart showing the present invention.

FIG. 3 is a perspective view showing a work.

FIG. 4 is a plan view showing a work.

FIG. 5 is a front view showing a work.

FIG. 6 is a plan view showing a work.

FIG. 7 is a perspective view showing a conventional technique.

FIG. 8 is an explanatory diagram showing a relationship between a laser sensor and a work.

[Explanation of symbols]

1 Work 2 laser sensor 3 grinder 4 Playback robots 4a hand section 5 controller P ₀ the starting point P _1, P ₂ operation point K, K _01, K ₁₂ pathway

Claims (1)

(57) [Claims] 1. A first surface which is provided on a hand portion of a playback type robot with an actual work machine and a distance sensor in a direction coinciding with the direction of the hand portion, and a tip of the distance sensor being a rotation center. The first position is the position in which the detection distance to the workpiece surface detected by the distance sensor when the distance sensor is rotated within the first position, and then a straight line representing the direction of the distance sensor in the first position A posture in which the detection distance to the workpiece surface detected by the distance sensor when the distance sensor is rotated around the tip of the distance sensor as the rotation center in a second plane that is orthogonal to the first plane is included. Sometimes, the teaching point is the intersection of the extension line of the distance sensor and the surface of the work, and from the data indicating the direction of movement of the hand and the shape of the work, a calculation point located in the direction of movement on the surface of the work is calculated and started. Connect points and operation points When moving the tip along the road, the amount of posture change in which the orientation of the tip is always perpendicular to the work surface is determined, and while maintaining the posture in which the orientation of the hand is perpendicular to the work surface, A teaching / control method for a playback type robot, wherein a hand is moved along a path connecting a start point and a calculation point, and actual work is performed by an actual work machine.