JPS6327138B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling a polishing robot, manipulator, etc., for performing polishing work by moving a polishing head along an arbitrary three-dimensional rectangular plane.

Generally speaking, polishing robots use the PTP method or CP method to teach the robot its work trajectory.
Since the robot is regenerated and driven according to this teaching trajectory, it is necessary to teach the entire working trajectory of the robot, etc.

However, when polishing the surface of a flat plate-like object such as a door or panel, the same reciprocating motion is often repeated, and in such cases, one repetitive process is taught, After that, by teaching the number of repetitions and the direction of the work, teaching over the entire plane is completed, and teaching efficiency is significantly improved.

As a control method for the above-mentioned polishing robot, etc., an industrial robot that operates on a workpiece surface is taught at least three points on the workpiece surface, as described in Japanese Patent Application Laid-open No. 57-17015. A method of controlling an industrial robot is known, which is characterized in that the robot is controlled within a plane area defined by the three taught points.

However, in this method, the three points taught are:
The condition is that it is the apex of a right triangle constituting three corners of a rectangular plane, which has the disadvantage that it takes too much time to teach.

Therefore, an object of the present invention is to improve the above-mentioned conventional method of controlling a polishing robot, etc., and to further improve the workability. In a method of controlling a polishing robot, etc. for moving a polishing robot, there is a step of teaching the position coordinates of three arbitrary points A, B, and C in space, and a step of teaching the position coordinates of three arbitrary points A, B, and C. Equal to the length of the perpendicular line CH drawn from C to side AB, side AB
The process of finding the positional coordinates of point D, which constitutes side AD perpendicular to side AB, on the same side as point C, and the process of calculating the number of work passes in the AD direction from the feed pitch of the polishing head and the distance between AD. and the working speed components Vx, Vy, in each direction from the vector AB→ and the working speed V.
Among the steps of calculating Vz and the normal vector from the position coordinates of points A, B, and C to plane ABC,
a step of calculating the normal vector in the direction opposite to the polishing head and determining the normal vector whose inner product is negative with the direction vector of the polishing head;
This point includes a step of sending the polishing head in the direction of this normal vector.

Embodiments embodying the present invention will be described in detail below with reference to the accompanying drawings. Here, FIG. 1 is a perspective view showing an example of a manipulator that is the basis of the present invention, FIG. 2 is a perspective view of a working plane showing a teaching method used in a control method according to an embodiment of the present invention, and FIG.
The figure is a flowchart showing the procedure of the control method.

In the following embodiment, as shown in FIG. 1, a case will be described in which a grinder G is attached to the wrist Hs on the slave side of the manipulator and a grinding operation is performed. FIG. 1 shows the casting surface 2 of the casting body 1 being polished by an angle type grinder G to finish the surface 2.

A teaching procedure for surface polishing using such a polishing robot will be explained with reference to FIGS. 2 and 3. Note that the step numbers are represented by a, b, c, . . . .

The operator operates the master wrist Hm to guide the polishing head G attached to the slave wrist Hs onto the work surface 2, and teaches the position coordinates of the following points on the work surface 2 (step a).

That is, as shown in FIG. 2, the operator guides the polishing head G to stop at the first corner A of the rectangular plane 2 to be polished, and stores the positional information in the memory of the computer.

This position information actually includes output values from rotation angle detectors such as resolvers, rotary encoders, and potentiometers installed at each joint of the robot, as well as the amount of protrusion and retraction of hydraulic cylinders, ball screws, etc. that operate the robot arm, etc. However, for the sake of simplicity, the following explanation will be based on position information considered in a rectangular coordinate system. Therefore, the position information of point A is expressed by rectangular coordinates (Xa, Ya, Za).

Next, the detection head G is guided to the second corner B, and its position information (Xb, Yb, Zb) is input and stored, and the polishing head G is guided to the side opposite to the side AB.
It is guided to an arbitrary point C on DE, and its position information (Xc, Yc, Zc) is input and stored.

The length of the vertical CH drawn from point C to side AB, that is, the length l of side AD, and the position coordinates of points D and E (Xd,
Yd, Zd) and (Xe, Ye, Ze) are obtained by simple geometric calculations. The explanation of the calculation method will be omitted here. At the same time, the length l of the above side AD
The number of work passes Np in the AD direction is determined from the feed pitch Δl of the polishing head in the AD direction (b).

Np=l/Δl The feed pitch Δl is determined from the polishing width of the polishing head G.

Also, the feeding speed of the polishing head G in the AB direction, that is, the working speed V, is input from the operation box (c), and points A,
Determine the vector AB→ in the AB direction from the position coordinates of B (d). From the vector AB→ obtained in this way and the working speed V, the working speed component Vx in the X, Y, and Z directions,
Find Vy and Vz (e).

Furthermore, the vector AC→ in the AC direction is determined from the position coordinates of points A and C (f), and the normal vectors 〓+ and 〓- of the taught plane ABC are expressed as 〓+=AB→×AC→/|AB→× Determine from AC → | and 〓−=−〓+ (g).

Also, the vector in the axial direction of the polishing head G, that is, the tool direction vector 〓 is obtained from the rotation angle of each arm of the robot (h), and the vector 〓 in the depth direction of the taught plane ABC is the normal vector 〓 Among + and 〓-, it becomes equal to the vector 〓- in the direction where the inner product with the tool direction vector 〓 is negative (i). This is because in the case of an angle grinder, the axis of the grinder must be slightly inclined with respect to the normal line of work plane 2 (synonymous with plane ABC) during polishing work, and as shown in Fig. This is because the angle α between the vector 〓+ and the tool direction vector 〓 is an acute angle.

Since polishing work cannot be done deeper than a certain depth at one time, by specifying the depth Δm that can be polished in one polishing work and repeating this Mp times, Δm×Mp=m Polish for depth.

Therefore, in this embodiment, the taught feed pitch Δm in the depth direction of the plane ABC and the maximum feed amount (driving amount) m are input from the operation box, and the number of feeds in the depth direction Mp=m/Δm is calculated. (j).

When the teaching work described above is completed, the following regeneration work (polishing work) is started.

The operator moves the polishing head G to the work starting point A=
Move it to A1 and press the start work button. Then, the grinding wheel of the polishing head G starts rotating, and the polishing head G is driven in the direction of the vector = = - by the set feed amount Δm of 1 pitch in the depth direction, and the grinder is moved to the plane 2 at a predetermined depth. The polishing operation is performed at a speed V in the direction from point A (A1) to point B (B1) while controlling the blade to bite. The direction of this velocity V can be obtained by moving each arm in the directions of Vx, Vy, and Vz. Polishing work is performed only when going from A to B, and when returning from B to A, the polishing head G is retracted by a predetermined amount in the direction of the vector + to prevent the tool from coming into contact with the flat surface.

In this way, when the reciprocating work for one pass from A1 → B1 (polishing) and B1 → A1 (evacuation) is completed, move it by 1 pitch Δl in the AD direction and perform the reciprocating work from A2 → B2 → A2 in the same way as between A1 and B1. to be done.

In this way, the operator repeats the operations of polishing → retreat → Δl movement → polishing → retreat Np times to complete the polishing work for a depth of Δm on the rectangular plane ABCD.
The polishing head G is returned to the position of point A, and the polishing head G is driven in the depth direction by Δm again to perform polishing over the entire plane.

In this way, the polishing head G is successively pushed in by Δm, and the surface is polished a total of Mp times to a depth of m.
Finish all polishing.

As described above, the present invention is a method of controlling a polishing robot, etc., for moving a polishing head, etc. along an arbitrary rectangular plane, and includes a method for controlling a polishing robot, etc. at any three points A in space,
The process of teaching the position coordinates of B and C, and from the position coordinates of the above three points A, B, and C, the length of the perpendicular CH drawn from point C to side AB is equal to the length, and the length of point C is the same with respect to side AB. The process of calculating the position coordinates of the point D that constitutes the side AD perpendicular to the side AB, the feed pitch of the polishing head, the process of calculating the number of work passes in the AD direction from the distance between AD, and the vector AB and work speed. V
The process of calculating the working speed components Vx, Vy, Vz in each direction from
Among the normal vectors to ABC, the step of calculating the normal vector 〓- in the direction opposite to the polishing head and the normal vector 〓- whose inner product is negative with the direction vector 〓 of the polishing head is determined. Since this is a control method for a polishing robot, etc. characterized by the step of sending the polishing head in the direction of the normal vector 〓-, the three points to be taught do not need to form a right-angled triangle, and can be formed on a rectangular plane. It is possible to teach any position on one side, improving the efficiency of teaching work, especially when it is not possible to teach the vertex of a right triangle due to the arrangement of another device, resulting in a significant improvement in efficiency. It is something to do.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of a manipulator that is the basis of the present invention, Fig. 2 is a perspective view of a working plane showing a teaching method used in a control method according to an embodiment of the present invention, and Fig. 3 is a perspective view of the same control method. FIG. 4 is a flowchart showing the steps of the method, and is a side view showing the relationship between the polishing head and the work surface in the polishing operation state. Explanation of symbols: 1... Workpiece, 2... Working surface, G... Polishing head, V... Working speed, A, B, C... Teaching point.
Δl...Feed pitch in the width direction, Δm...Feed pitch in the depth direction, Vx, Vy, Vz...Working speed component, ABC...
Plane, 〓+, 〓-...normal vector, 〓...tool direction vector.

Claims (1)

[Claims] 1. In a method of controlling a polishing robot, etc. for moving a polishing head, etc. along an arbitrary rectangular plane,
A method for controlling a polishing robot, etc., comprising the following steps (1) to (6). (1) A process of teaching the position coordinates of three arbitrary points A, B, and C in space. (2) From the position coordinates of the three points A, B, and C above, the length of the perpendicular CH drawn from point C to side AB is equal to the side
Side perpendicular to side AB on the same side as point C with respect to AB
The process of finding the position coordinates of point D that constitutes AD. (3) From the feed pitch of the polishing head and the distance between AD
The process of calculating the number of work passes in the AD direction. (4) Step of calculating working speed components Vx, Vy, Vz in each direction from vector AB→ and working speed V. (5) A step of calculating the normal vector 〓- in the direction opposite to the polishing head among the normal vectors to the plane ABC from the position coordinates of points A, B, and C. (6) A step of determining the normal vector 〓- whose inner product with the direction vector 〓 of the polishing head is negative, and sending the polishing head in the direction of this normal vector 〓-.