JPH01140207A - Manual control method for robot arm - Google Patents

Abstract

PURPOSE:To widely shorten a teaching work time by using two or three points taught beforehand, defining an arbitrary coordinate system convenient for a teaching by the action teacher of a robot arm and operating the robot arm along the coordinate system. CONSTITUTION:When X-Y coordinate axes are converted and the robot arm is operated concerning new coordinate axes X'-Y', for example, two pieces of position information are taken out. Next, the present tip position of the robot arm and an action direction vector are used and an action limit position at the time of operating the robot arm in the action vector direction and the action distance at the time of operating it to the action limit position are obtained by an arithmetic unit 15. Next, an adjustable processing system at the time of operating the robot arm only at a prescribed action distance is determined in accordance with a maximum speed and an accelerating system specified beforehand. An action target position at the time of operating it at a minute distance in a prescribed action direction is obtained. This is converted into the position signal of a servo motor 2, a control signal is obtained and it is outputted to a PWM signal generating circuit 11. That an adjusting key is detached is detected and a whole arithmetic processing is terminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a robot motion control system, and particularly provides a motion control means that is effective in teaching the robot's motion point.

[Conventional technology]

An effective method for teaching an articulated robot its motion is to align the robot along each orthogonal axis of a specific orthogonal coordinate system that is independent of the robot's mechanics and that is uniquely associated with the robot's mechanics during robot design. It has been shown that operating the system is suitable for teaching work.

An example of this type of device is the one described in Japanese Patent Publication No. 51121/1983.

[Problem that the invention seeks to solve]

The method of moving the robot arm along orthogonal coordinate axes and teaching the operating point is of great value because it is a coordinate system that workers can easily recognize or that is the basis of their daily lives. However, the above-mentioned orthogonal coordinate system is a coordinate system uniquely defined at the time of robot design, and there is a problem in that the robot can only be operated along the orthogonal axes. In other words, if the coordinate system of the workpiece that is the target of the robot's work instruction does not match the coordinate system of the robot (and this usually does not match, and it is difficult to adjust it so that they match) If the robot is moved to a different location, readjustment will be required even if the adjustment is made, etc.), and if there are many work teaching points, each surface axis of the coordinate system Repeat the movement in the direction.

There is a problem in that the robot must be positioned to the target teaching point. This problem is also the same in the case of a surface motion type robot arm.

The present invention solves these problems and provides a method for simplifying the teaching of robot operating points.

[Means for Solving the Problems] The above object is achieved by providing means for converting the orthogonal coordinate system of the robot into the orthogonal coordinate system of the workpiece.

Specifically, in the orthogonal coordinate system of the robot, when the X-Y axes are on a horizontal plane and the Z-axis is the axis that intersects with the plane formed by the X-Y axes, (1) X- When you want to transform the Y coordinate system, teach two working points on the workpiece and find the horizontal component direction cosine of these two points.1 For example, redefine this direction cosine vector as the X' axis and orthogonal to it. This is achieved by setting the vector in the horizontal plane as the Y' axis and giving the robot the ability to move in the X' and Y' axis directions.

(2) When you want to convert the X-Y-Z coordinate system, teach three working points on the workpiece, set the direction cosine found from two of them as the X' axis, and use the remaining one point to Let the perpendicular line drawn to the axis be the Y' axis.

This is achieved by setting a straight line perpendicular to the X'-Y' plane as the Z' axis, and giving the robot the ability to move in the X', Y', and Z' axis directions.

[Effect]

The operation of the present invention will be explained using FIGS. 1 to 3.

Here, for the sake of simplicity of explanation, a case will be shown in which the horizontal plane is redefined. In FIG. 1, a robot-specific orthogonal coordinate system x-Y is defined with the robot body as the origin of coordinates as shown in FIG. On the other hand, it is assumed that the coordinate system x'-y' of the workpiece to be operated by the robot is as shown in FIG.

Here, the Q marks are the operation teaching planned points, and these are aligned on the workpiece coordinate system. Here, for example, assume that the robot is taught the dotted O mark and ■ by operating it in the usual way. From these two points, a directional vector from point I to the point as shown by the arrow in FIG. 1 can be calculated. Therefore, if this is defined as the X'-axis direction, the Y'-axis direction perpendicular to this can also be defined. Here, the method of teaching the two points is arbitrary, and it goes without saying that the X'-axis direction can be determined from the two taught points.

Next, a conventional procedure for teaching an operating point will be described using FIG. First, it is assumed that the teaching up to point I has been completed and the next point will be taught. In order to move the tip of the robot arm from point to point, the robot movement instructor moves the robot's own coordinate axis X by operating the operation switch.
Alternatively, move the robot along the Y-axis direction as shown in Figure 2, repeat the movement in the X- or Y-axis direction near the dot, make fine adjustments, and then move the tip of the robot arm to point D. Position. Next, by operating another operation switch, the light is stored in the robot control device.

The same applies to the teaching at point B. Since the location of the teaching point and the direction in which the robot can move are different, it is necessary to move the robot by combining various movement directions and position the robot arm at the target position. Adjustment is very tricky.

Next, the procedure for teaching the operating point of the present invention will be described using FIG. First, assuming that the positions of the two points for determining the x'-y' coordinate axis have already been taught and the teaching of the motion up to the teaching point has already been completed, a case will be described in which the primary point is taught. In order to move the tip of the robot arm from point ■ to point D, the robot movement instructor must first operate the control vessel to send a command signal for moving the robot arm in the X'-Y' coordinate system to the control device. Teach to. This makes the operating mode based on the X'-Y' coordinate system. Next, if you operate the operation buttons in the same way as above, in this case.

The robot arm tip moves along the X' or Y' axis.

Therefore, in order to move the robot from point to point, it is sufficient to push a certain operating vessel, and the robot arm moves in the direction of the point as shown by the arrow in FIG. The point for fine adjustment near the point is the same as before, but this is also
It is very easy to adjust only in the axial direction. Next, when teaching point B, it is possible to teach by simply moving it in the Y'-axis direction using another operating vessel.

Furthermore, a hidden advantage of the present invention is that a robot motion instructor can arbitrarily define a coordinate system convenient for teaching, and can teach the robot's motion points on that coordinate system. A teaching point can be taught as a point exactly on a straight line, and a point arranged on a rectangle is at a point that can be taught as an exact point on the rectangle. On the other hand, according to the conventional teaching method, even if the points are arranged on a straight line, unless the straight line coincides with the robot's own coordinate axes, the motion in the X-axis and Y-axis directions is repeatedly taught. Therefore, points arranged exactly on a straight line cannot be taught as being located on a - straight line. Even when teaching points arranged in a rectangular shape, it is not possible to teach them as accurate rectangular points.

〔Example〕

FIG. 4 shows an example of the configuration of a robot system that implements the present invention. The robot system is composed of a robot body 2 and a control device 1. The control device 1 manually operates the robot, instructs the position storage means 18 to store the operated position, inputs the operation procedure of the robot, instructs the operation means storage means 17 to store it, and stores the operation procedure. A teaching means 14 including a plurality of operation switches for instructing the robot to operate according to the operation procedure stored in the storage means 17 and a display device for displaying operation status, etc.
In response to the pwM command output from the calculation means 15, the PWM
A PWM signal generation circuit 11 that generates a signal, a power circuit 12 that operates based on the PWM signal and supplies operating current to the robot body 2, particularly the servo motor, and a power circuit 12 that is attached to the servo motor to measure the rotational position of the servo motor. a pulse counter 13 for counting the encoder pulses of the encoder that has been moved; a position storage means 18 for storing the positions passed by the tip of the robot arm; and a position storage means 18 for storing operation procedures for the plurality of positions stored in the position storage means 18. and an operation procedure storage means 17.

Arithmetic procedure storage means 1 for storing the arithmetic procedure of the arithmetic means 15
6 and is stored in the calculation procedure storage means 16 determined according to the input signal of the teaching means 14. It consists of a calculation means 15 that reads an appropriate calculation procedure and performs calculations using information stored in the operation procedure storage means 17 and the position storage means as necessary to control the robot's operation.

FIG. 5 shows an example of the operating vessel and display section of the teaching means 14.

Hereinafter, the operation of the robot according to the present invention will be explained in detail.

In order to start the operation of the robot, first, when the main power switch (not shown) is turned on, the calculation means 15 shown in FIG.
initializes the robot's movements and display. Next, when the origin setting key shown in FIG. 5 is pressed, the calculation means 15 operates the robot according to a predetermined procedure and causes the robot to assume a mechanical reference posture.

As a result, the correspondence between the robot mechanical posture and the position information is established, and the robot becomes program controllable.

First, a method of teaching operating points for defining an arbitrary coordinate system according to the present invention will be explained. By pressing the position teach key in FIG. 5, the robot enters position teach mode. In this state, by pressing any of the position adjustment keys shown in Figure 5, the robot will move at a predetermined speed in a predetermined direction for each adjustment key, and will stop when the adjustment key is pressed. It works like this. For example, if the key on the right side of the arm in FIG. 5 is pressed, the tip of the robot arm moves in the direction of the X-axis arrow in FIG. 1, and if the key in front of the arm is pressed, the tip of the robot arm moves in the direction of the Y-axis arrow in FIG. By operating the adjustment keys in this manner, the tip of the robot arm can be positioned at an arbitrary point. 5th point for the positioned point
After operating the data input key shown in the figure to input the position number for which the position information of the positioning point is to be stored (this is displayed, for example, in the step section of Fig. 5), press the set key shown in Fig. 5. , the current robot position information is stored in a predetermined storage area of the position storage means 18 for the input position number.

Here, the position information stored in the position storage means 18 is the integrated value of the encoder pulse signal that gives the rotation angle of the servo motor 2, or the x, y coordinate system determined uniquely to the robot calculated from this. , z value, or, in the case of an articulated robot, the rotation angle of the arm.

In short, the position information of the tip of the robot arm itself, or the position information and the same information by performing some calculation processing.
:Anything that can be associated with 1 is fine.

Next, position information is taught and stored in this way.

We will show how to define the basic data of a new coordinate system defined by a robot motion instructor.

The first method is to consider the position information of two points stored in a specific area of the position storage means 18 as basic data of a new coordinate system. Since the specific area corresponds to the position number as described above, the robot motion instructor can input this information by inputting a specific position @mount number and pressing the set key as described above. is the position storage means 1
8 specific areas.

In the second method, when a specific symbol is input into the operation code display section of FIG. The basic idea is to perform definition processing. For example, when inputting ``7'' in the operation code display section, the first input is II 8. When inputting II, the second input is 1197.
When 1 is input, the third coordinate system definition position is defined. In this case, when the above-mentioned specific symbol is input into the operation code display section and the set key is pressed, the calculation means 15 determines whether the above-mentioned position information is to be stored or coordinate system definition input is to be performed using the above-mentioned specific symbol. Distinguish by presence/absence. If there is no specific symbol, processing is performed to store position information, which is described above. If the coordinate system definition input, ie, It 7 II, II 8 II or 29''' in the above example is input in the opcode display.

The position number displayed on the step part is taken in and stored in an area prepared according to the specific code. In the case of the first method, when defining or redefining the coordinate system, the robot must be moved to the position to be defined, whereas in the case of the second method, it is necessary to move the robot to the position to be defined. You can freely specify the position of the robot without moving it.

In the manner described above, position information for defining a new coordinate system can be specified.

Next, using the location information specified as above,
We will show how to move the tip of the robot arm along the coordinate axes of the newly defined coordinate system.

To do this, first, it is necessary to instruct the control device 1 to operate the robot arm along the newly defined coordinate axes. The method includes, for example, pressing a utility key followed by a specific code predetermined to indicate the above, e.g.
This is achieved by sequentially inputting I, II Ql'' using the data entry key and pressing the set key.The control device decodes the above input and enters the operating mode.Another example is Although not shown in the figure, another key may be provided, and pressing this key can switch between a mode in which the robot arm moves according to its own coordinate system and a mode in which it moves according to a new coordinate system. That is, any means may be used as long as it can instruct the control device 1 to move the robot arm along the newly defined coordinate axes.

How to move the robot arm after entering the operation mode of moving along the new coordinate axes in this way will be explained using FIG. 6. When any of the position adjustment keys is pressed, the operation shown in FIG. 6 is started. First block 00
Primary processing is performed at o. The two pieces of position information stored for the new coordinate axis definition are retrieved using the method described above (with some transformation if necessary). Here, we are explaining the case where the X-Y coordinate axes are converted and the operation is performed on the new coordinate axes x'-y', so the two position information P
0. P-engine consists of the following vector components.

Pa'' (P-x, Pay) P = (p-x-pty) From this, the direction of the X'' coordinate axis is given by the following direction vector.

In block 001, the following processing is executed.

That is, when the "arm right" adjustment key is pressed, the movement direction vector υ of the arm is set as follows.

If the adjustment key for ``Arm Left'' is pressed.

If the "Arm Front" adjustment key is pressed.

When the "arm rear" adjustment key is pressed, the direction in which the tip of the robot arm should be operated is determined in this way.

Next, in block ''002'', preparatory calculations of operating conditions are performed. That is, when the robot arm is moved in the direction of the motion vector using the current robot arm tip position PN=(PNXI PNy# PNZ) and motion direction vector υ, the motion limit position P[! =(Fax
+P[+yt PEZ) and the operating distance a0 when operating to the limit position. Next, the operating distance Q is determined according to the predetermined maximum speed and acceleration/deceleration method. Determine the acceleration/deceleration processing method when operating the robot arm. The details of the calculation processing are not the main focus of the present invention, so they will be omitted here.

Next, in block "003", the target operation position P is determined in the case where the operation is performed by a predetermined minute distance ΔQ in the operation direction υ.

p=p, , +ΔQ・υ Convert this into a position signal for the servo motor that drives the robot arm according to the calculation formula related to the robot mechanism,
Determine the control signal according to appropriate control logic and apply it to PW
It is output to the M signal generation circuit 11. As a result, the robot arm moves by a very small distance ΔQ along the motion direction υ.

Next, in block "004", a check indicated by block "005" is performed for a predetermined period of time, for example, 1 sec. When it is detected in block "005" that the adjustment key has been released.

All arithmetic processing ends. This function means that by pressing the adjustment key for a very short time, the robot arm can be moved a very small distance in the direction specified by the adjustment key, which is useful when accurately positioning the robot arm to the target point. This shows that it is effective for position adjustment. here,
If the same adjustment key is held down for a predetermined period of time, the next block "o" will be displayed.

Execute 6″.

Block "006" starts the operation of block "007" at fixed time intervals, which is related to the sampling rate of the servo system, for example, every 2 msec.

Here, block "006" is an example in relation to servo control, and there are various types of actual processing.

In block "007", as in block "005", it is checked whether the same adjustment key continues to be pressed. If pressed, block ''008''''”0
09'' is executed. In block ``008'', it is checked whether the robot arm has reached the operating limit point determined in block ``002''. If so, all processing ends. If not reached, block”
According to the acceleration/deceleration conditions determined in step 002'', the operating distance Q of the next point at which the robot should move is determined, and the operating point P is obtained.

P=PN+Qυ The procedure for moving the robot using this P is the block''
This is the same as that explained in ``Oo3''. By executing the process of block ``009'' at regular time intervals, the robot arm continuously moves along the motion direction υ according to a predetermined acceleration/deceleration method. If the key continues to be pressed, the robot arm will eventually reach its operating limit and stop.

If the robot arm is to be stopped at a desired position, the motion instructor only has to release the adjustment key.

When the adjustment key is released, block "010" is executed. In other words, the operation target position for decelerating and stopping the robot arm according to the deceleration conditions obtained in block "002" is set to "0".
10"Although omitted in the block explanation, the block"
Blocks "006" to "010" occur at similar fixed time intervals and act on the servo system to stop the robot arm.
Due to this action, the robot arm moves along the movement direction and is positioned near the target position. The exact positioning method is as described above. Incidentally, in the above description, some aspects of the operation of the practical system, such as safety checks, operability/inoperability checks, etc., which are not the main purpose of the present invention are omitted.

The above is a detailed explanation of the case where plane coordinates are arbitrarily defined and the robot arm is operated along the coordinate axis direction. Although the explanation has been made assuming that this plane is a horizontal plane, it can also be realized using a similar concept when it is a vertical plane. Furthermore, if spatial coordinates are arbitrarily defined and the robot arm is operated along each of the coordinate directions, this can be achieved using a similar method, so a detailed explanation will be omitted here.

〔Effect of the invention〕

As explained above, using two or three points taught in advance, the robot arm movement instructor can define a new coordinate system that is arbitrary and convenient for teaching the movement, and each axis of this coordinate system Since the robot arm can be moved along the direction, the present invention has the great effect of simplifying and simplifying the teaching work and significantly shortening the teaching work time. .

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention. FIG. 2 is a diagram explaining a conventional motion teaching procedure. FIG. 3 is a diagram illustrating the operation teaching procedure of the present invention. FIG. 4 is a side view of the overall system configuration of the present invention. FIG. 5 is a side view of the teaching means of the present invention.゛FIG. 6 is a procedure diagram for manually operating a robot arm using the present invention. 1st cause 22nd 3rd ward

Claims (2)

[Claims] (1) Determine a direction vector axis in a horizontal or vertical plane, which is determined from two position data of the robot arm that have been taught and stored in advance, and a vector axis perpendicular to the vector axis in the plane, and teach the robot arm movement. A manual control method for a robot arm, characterized in that the tip of the robot arm is moved along a straight path along an axis and direction selected by an operation button of the device. (2) A direction vector axis obtained from the first two of the three position data of the robot arm that has been taught and stored in advance, a direction vector axis that is perpendicular to this axis and passes through the last point, and a direction vector axis that is perpendicular to this axis and passes through the last point. A directional vector axis perpendicular to a plane determined by the vector is determined, and the tip of the robot arm is made to move along a straight path along the axis and direction selected by the operation button of the robot arm motion teaching device. Manual control method for robot arm.