JPS5878205A - Teaching method for industrial robot - Google Patents

Abstract

PURPOSE:To determine easily the movement direction of a robot independently of the position of a work, by defining the direction, to which an arm of a robot having a multijoint structure is turned, as a temporary reference and moving the robot vertically and horizontally from this position. CONSTITUTION:A Y'-axis to which a lower arm 3 and an upper arm 4 are directing is used as a temporary reference axis to move a robot from a point P to a point P' which is placed in the direction vertical to the Y'-axis (in the direction of a temporary reference axis X'). Reference axes X and Y are rotated at an angle theta to reference axes X' and Y', and all angles corresponding to 5 degrees of freedom including this angle theta are always inputted to a controlling means, and the value of this angle theta is used in the internal operation. A target position in the XYZ coordinate system is operated by the internal operation processing and is converted to a target value in the arm angle theta system by the reverse coordinate conversion, and the servo control with data in this theta system as a target value is performed. Thus, the operator determines the movement direction of the robot easily without errors independently of the position of a work 10.

Description

[Detailed Description of the Invention] The present invention relates to a teaching method for an industrial robot,
In particular, the present invention relates to a teaching method for operating a robot arm using a teaching box in an articulated robot that performs FTP teaching CP playback control.

What defines the robot's posture is the angle formed by each axis of the robot. For example, in an articulated robot with five degrees of freedom (Sl, S2, S3, 84, 85) as shown in FIG. and a ten arm 3 having one end fixed to and extending upward.

The upper arm 4 is connected at the upper end of the lower arm 3, and the wrist portion 5 is provided at the tip of the upper arm 4. Angle θ2 based on the angle 039 formed by the upper arm 4 and lower arm 3 Angle θ4' based on the vertical bending of the wrist portion 5
and the angle θ5 based on the rotation of the wrist portion 5 can be independently operated. And this independent operation is
A drive unit 6 (including a servo motor and a hydraulic motor) provided corresponding to each axis performs the operation in response to an operation command from a control panel.

However, it is difficult for the person who teaches the robot the motion path points to decide how to define the angle and what kind of posture the robot will take. Therefore, usually
An XYZ coordinate system fixed to the robot is used, and the robot's position data is subjected to coordinate transformation processing (
All the processing in the arithmetic/control means and the data in the storage means are data based on the XYZ coordinate system.

The origin of the XYZ coordinate system is 0, which is the connection between the turntable 2 and the lower arm 3, and the Z-axis is the upward direction from a fixed fixed position for installing the base 1, as shown in the plan view of Figure 1. The direction in which the upper arm 4 faces straight (perpendicular to the workpiece 10) in plan view with respect to the initial posture of the robot is defined as the Y-axis, and the direction perpendicular to this Y-axis in plan view is defined as the X-axis. The angles θ1 to θ5 and X, Y with respect to the initial posture are determined in advance.
, and the Z coordinate.

By the way, conventionally, a teaching box as shown in FIG. 3 is used during teaching. That is, 20 is an operation unit for positioning each axis of the robot, 21 is a toggle switch for moving the robot in the X-axis direction, and 22 is a Y-axis switch.
In the axial direction, 23 is a toggle switch for moving in the X-axis direction.

Further, 24 is a switch for raising and lowering the wrist portion 5;
5 is a switch operated to rotate left and right.

However, as shown in FIG. 2, when the workpiece 10 is located almost in front of the robot, the operator can easily distinguish the X, Y, and Z movement directions when moving the arm, but the workpiece 11. When the workpiece 12 is positioned obliquely to the robot, it is difficult to know how to move and operate it in the X, Y, and Z directions. especially,
This is especially true when the operator is close to the workpiece 11 or 12 and visually checks the route to be taught.

Therefore, an object of the present invention is to provide a teaching method that allows an operator to easily and accurately determine the direction of movement of a robot, no matter where the workpiece is placed within the robot's operating range. Moreover, it is possible to use a conventional teaching pendant as is.

In order to achieve the above object, the present invention provides a method for teaching an articulated robot by operating a teaching box, in which the direction in which the robot's arm is facing is defined as front and back, and the direction perpendicular to this direction is left and right,
With the up and down direction as up and down, the front/back, left/right, and up/down operations are performed using conventional X and Y operations.

Instead of operating a switch on the Z-axis, when the switch is operated, the robot is operated based on pre-programmed software using the direction in which the arm is facing as a temporary reference.

Examples will be described below.

The teaching pendant used in the method of one embodiment is the fourth
As shown in the figure, the display on the conventional operation unit 20 is as follows: It is used by rewriting ``upper j'' for rear J and rZ-J, and ``lower'' for r-ZJ. This is to make the operation easier, and there is no difference in functionality from the conventional one.If you push the toggle switch from the neutral position to the "right" position, for example,
Command signals are simply output from the teaching box to the control panel via a specific path. The control means of the control panel performs predetermined operations based on this command signal.

The control means includes a computer, preferably a microprocessor or microcomputer. The control means responds to the movement command by a unit movement amount (ΔX) in each of the x, y, and z axis directions every fixed positioning control period Tc (for example, TC=20ms).

Δγ, Δ2). For example, in the conventional example, when moving in the X-axis direction from point P (XP, YP, ZP) in FIG. 5 (turn switch 21 in FIG. 3 to "X"), after Tc, point P ΔX.

yp, zp), and if you keep pushing it to the rXJ side, the point P (xp+nΔx,
yp, zp). - However, in the method of the present invention, the point P(xp, yp.

Y, which is the direction in which arms 3 and 4 are facing from
' axis as a temporary reference axis, point P (x
p', yp', zp'). Turn switch 21 on the note-teaching box in Figure 4 to the "right" direction. After one period Tc of control, (xp+Δxcosll
.

yp+Δysinθ, Z15), and nTc
Later, (xp+n cosθ+ yPtenΔysinθ
, zP)=(xP'yp', zp') can be moved to one point P'. Here, θ is the angle of one rotation from the reference axes X, Y to the temporary reference axes X', Y'. In other words,
This is the angle of rotation around the <Sl axis based on the rotation of the turntable 2 from the initial basic posture of the robot. This angle θ
Since all angles corresponding to the five degrees of freedom including the angles are constantly input to the control means by the position detector serving as an internal world measurement function, the control means can use this position data at any time. Therefore, it is possible to latch the angle θ at the time the switch is pushed to the “right” and hold it until there is no switch output, and use this value of θ in internal calculations.

Once the target position in the XYZ coordinate system is calculated by internal calculation processing, it is converted into the eye value in the arm angle θ system by inverse coordinate transformation, and the servo control is performed using this θ system data as the target value. There is no difference from normal robot control.

In short, when the operation unit 2o of the teaching pendant is operated, the unit increment for each positioning control cycle Tc is Δx cos θ in the X-axis direction when the "right" direction is commanded.

It is converted to move Δγ sin θ in the Y-axis direction, and if it is commanded to "left", it moves Δx cos (θ + π) in the X-axis direction.
, is converted to move by Δysin (θ+π) in the Y-axis direction.

Furthermore, if "front" is commanded, the movement is made by Δxcos in the X-axis direction. The "up" and "down" directions are the same as before.

Note that θ here is a radian angle.

Such calculations are set in advance in a computer program, and are executed by the control/calculation means immediately performing calculation processing based on the input of the off-switch command.Such a program can be easily created by a person skilled in the art. It can be easily designed and incorporated into a robot control system.

As described above, according to the present invention, the direction in which the arm of the multi-jointed robot faces is used as a temporary reference, and the workpiece is moved forward, backward, left and right by operating the switch on the teaching pendant from that position. Even if the robot is placed in a different position, the operator can easily and accurately determine the direction of movement of the robot without any confusion.

Furthermore, since a conventional teaching pendant can be used as is, it does not increase costs and contributes to improving cost performance.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an articulated robot, in which (a) is a side view and (b) is a plan view. . Fig. 2 is an explanatory diagram of the position of the workpiece relative to the robot, Fig. 3 is an external view of a conventional teaching box, Fig. 4 is an external view of a teaching box applied to an embodiment method of the present invention, and Fig. 5 is an external view of the teaching box. FIG. 2 is an explanatory diagram of a method according to an embodiment of the invention. 2... Turntable, 3... Lower arm, 4...
Upper arm, 30... Teaching box positioning operation unit, 31... Left and right toggle switch, 32...
...Toggle switch for forward and backward directions.

Claims (1)

[Claims] (1) A method of teaching an articulated robot by operating a teaching pendant, in which the horizontal line included in the plane formed by the axes of multiple arms of the robot is defined as the first axis, and this first axis A second axis is set in the horizontal direction orthogonal to the second axis, and the second axis is set in the horizontal direction perpendicular to
A teaching method for an industrial robot, characterized in that teaching is performed by directly moving the robot in a direction along an axis or in a direction along the first axis.