JPH0431831B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention has a dedicated drive shaft (hereinafter referred to as Z-axis) that can move a hand or arm up and down vertically, and a dedicated drive shaft that can move a hand or arm horizontally. This invention relates to a control device for a robot that has multiple drive axes (hereinafter referred to as XY axes).

[Prior art] Normally, in order to make a robot do a job, the Z-axis moves up, then the XY-axes move horizontally, and finally the Z-axis moves down, as shown in Figure 1A.・ Place movement is required. In conventional control devices, there was only a single movement control circuit with a built-in calculation function, so the pick-and-place operation was divided into three operations, and after each operation was completed, the movement was started. In other words, after the Z-axis ascends, accelerates, decelerates, and stops, the XY
The axis starts accelerating, decelerates and stops, and then Z
It controlled the shaft to begin descending.

[Problems to be solved by the invention] In order to shorten working time, it is necessary to increase the speed of robot operation, but unnecessarily increasing acceleration or speed will have a negative impact on the life of the robot. I end up.

Conventional control devices execute each operation in sequence as described above, so the only way to increase the speed of a robot is to increase its speed and acceleration, which either sacrifices its lifespan or requires significant mechanical parts. They dealt with it by reinforcing it.

In addition, some control devices move to the next operation without confirming that the drive shaft has completely stopped after the pulse output from the drive control circuit ends, causing electrical and mechanical delay time in the drive system. There are also items that are trying to shorten the time.

The purpose of the present invention is to reduce the moving time of robots,
The aim is to shorten the working time.

[Means for Solving the Problems] A robot control device according to the present invention has a drive shaft for vertically moving a hand or arm and one or more drive shafts for horizontally moving the hand or arm. , the control device has a vertical movement control circuit and a horizontal movement control circuit that are independent of each other, and the vertical movement control circuit includes means for calculating an acceleration end timing or deceleration start timing of the hand or arm, and a means for calculating an acceleration end timing or deceleration start timing of the hand or arm. means for generating a signal A to notify the horizontal movement control circuit that the timing has come, and the horizontal movement control circuit has means for predicting the time required for the downward movement of the hand or arm; means for calculating a horizontal movement speed at which the remaining time until the horizontal movement of the hand or arm is completed is shorter than the predicted time required for the lowering; and means for detecting that the hand or arm has reached the horizontal movement speed; means for generating a signal B to notify the vertical movement control circuit that the horizontal movement speed has been reached, and the horizontal movement control circuit starts horizontal movement upon receiving the signal A from the vertical movement circuit; The horizontal movement control circuit is characterized in that it receives the signal B from the horizontal movement control circuit and performs a downward movement.

Furthermore, when performing interpolation control in the vertical and horizontal directions simultaneously, the present invention is characterized in that movement of all axes is controlled by only either the vertical movement control circuit or the horizontal movement control circuit.

[Function] The present invention realizes speeding up of the robot by executing multiple movement controls in parallel. , and before it ends, the Z-axis begins to descend. Therefore, as shown in FIG. 2B, the arm of the robot can perform pick-and-place operations without stopping midway, making it possible to significantly shorten the working time.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 3 shows an example of the overall configuration of drive control within the control device according to the present invention.

In the same figure, in response to the movement command 1, the vertical movement control circuit 3 outputs a Z-axis ascending pulse 6, and 8
The Z-axis drive pulse 9 enters the 12 servo drive circuits through the pulse selection circuit. On the other hand, the horizontal movement control circuit No. 2 does not output a horizontal movement pulse even if it receives the movement command No. 1, and the horizontal movement start timing signal, which is the signal A described in the claims, is output from the vertical movement control circuit No. 3. 4 (hereinafter referred to as horizontal movement start timing signal 4), output of an X-axis drive pulse 10 and a Y-axis drive pulse 11 is started.
Pulses 10 and 11 are both input to the servo drive circuit 12, and 12 is the X-axis motor 13 and the Y axis motor 14.
Axis motor, drives 15 Z-axis motors. After the output of the Z-axis rising pulse is completed, the vertical movement control circuit No. 3
In response to the downward movement start timing signal 5 (hereinafter referred to as the downward movement start timing signal 5), which is the signal B described in the claims from the horizontal movement control circuit No. 2, a Z-axis downward pulse is outputted to No. 6. Like the rising pulse, the falling pulse is outputted as a Z-axis drive pulse 9 through 8 pulse selection circuits, and is input to 12 servo drive circuits. In the case of XYZ simultaneous interpolation control, 8 is 1 because the Z-axis drive pulse is output from the horizontal movement control circuit 2 to Z-axis drive pulse 7.
This is to select either 6 or 7 signals to be input to the servo drive circuit No. 2.

Figure 4 shows the flow of processing within the movement control circuit.
The figure shows the acceleration/deceleration curves of the XY and Z axes. In Fig. 4, when movement command 1 is received, the horizontal movement control circuit 2 calculates the required time a for downward movement shown in Fig. 5 from the downward movement amount according to a predetermined acceleration/deceleration curve by means 21. . Based on this result, the means 22 calculates the XY-axis horizontal movement speed v at which the Z-axis downward movement should be started using the following formula.

v≦(a/b−c)v ₀ Here, b is the horizontal movement principle time calculated from the predetermined acceleration/deceleration curve and the horizontal movement amount, and c is the horizontal movement time that remains somewhat even after the horizontal movement is completed. It is a predetermined offset amount so that there is downward movement, and v ₀ is the maximum speed of horizontal movement. The above formula approximates the principle curve of horizontal movement to a straight line, but other curves can also be applied to the above formula by adjusting the offset amount of c, as long as they do not deviate significantly from the straight line. .

On the other hand, in the vertical movement control circuit 3, the means 23 calculates an appropriate timing to start horizontal movement, such as the end of upward movement acceleration or the start of deceleration, and the upward movement pulse output means 24 outputs a Z-axis drive pulse. Output. The timing detection means 25 detects that the timing calculated by the means 23 has been reached during the upward movement, and outputs a horizontal movement start timing signal 4. In the horizontal movement control circuit No. 2, the judgment means No. 26 activates the horizontal movement pulse output means No. 27 to output XY-axis drive pulses.
The timing detection means of 28 has a horizontal movement speed of 22
It detects that the speed has been reduced to the calculated speed by means of , and outputs a downward movement start timing signal 5.
The determining means 29 confirms the input of the downward movement start timing signal 5 and the end of the upward movement, and activates the downward movement pulse output means 30. The determining means 31 confirms that both the horizontal movement and the downward movement have been completed, and outputs a processing end signal 32.

[Effects of the Invention] As is clear from the above explanation, according to the present invention,
By starting the XY-axis movement before the Z-axis has finished rising, and starting the Z-axis descent before the XY movement has finished, the robot arm's pick-and-place can operate smoothly. Therefore, the work time can be shortened without increasing the movement speed of the single axis. Furthermore, although the horizontal movement and vertical movement are controlled independently, timing is exchanged with each other, so there is no need to pull or hit the workpiece.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the operation of the end of the arm in pick-and-place operation by the control device, A is a conventional operation diagram, and B is an operation diagram of the present invention. FIG. 2 is a diagram showing the relationship between the speed and time of the pick-and-place operation by the control device, A is the relationship diagram of the conventional example, and B is the relationship diagram of the present invention. FIG. 3 is a diagram showing an example of the overall configuration of the drive control section of the robot control device according to the present invention. FIG. 4 is a diagram showing an example of a processing procedure within a control circuit according to the present invention. FIG. 5 is a diagram showing acceleration/deceleration curves of the XY axes and the Z axis. 1...Movement command, 2...Horizontal movement control circuit, 3
... Vertical movement control circuit, 4 ... Horizontal movement start timing signal, 5 ... Downward movement start timing signal, 6 ... Z-axis rising pulse, 7, 9 ... Z-axis drive pulse, 8 ... Pulse selection circuit, 10...X-axis drive pulse, 11...Y-axis drive pulse, 12...Servo drive circuit, 13...X-axis motor, 14...Y
Axis motor, 15...Z-axis motor, 21... Descending movement time required calculation means, 22... Descending movement start timing calculation means, 23... Horizontal movement start timing calculation means, 24... Upward movement pulse output means,
25, 28...timing detection means, 26, 2
9, 31... Judgment means, 27... Horizontal movement pulse output means, 30... Downward movement pulse output means, 3
2...Processing end signal.

Claims (1)

[Scope of Claims] 1. A robot control device having a drive shaft that moves a hand or arm in a vertical direction and one or more drive shafts that move a hand or arm in a horizontal direction, wherein the control device includes mutually independent vertical movement control circuits. and a horizontal movement control circuit, and the vertical movement control circuit includes means for calculating an acceleration end timing or deceleration start timing of the hand or arm, and means for detecting that the hand or arm has reached the timing, and a means for calculating the acceleration end timing or deceleration start timing of the hand or arm. means for generating a signal A to notify the horizontal movement control circuit that the timing has come, and the horizontal movement control circuit has means for predicting the time required for the downward movement of the hand or arm; means for calculating a horizontal movement speed at which the remaining time until the horizontal movement of the hand or arm is completed is shorter than the predicted time required for the descent; and means for detecting that the hand or arm has reached the calculated horizontal movement speed, means for generating a signal B to notify the vertical movement control circuit that the horizontal movement speed has reached the specified horizontal movement speed, and the horizontal movement control circuit starts horizontal movement upon receiving the signal A from the vertical movement control circuit. The robot control device is characterized in that the vertical movement control circuit starts downward movement upon receiving the signal B from the horizontal movement control circuit. 2. When performing interpolation control in the vertical and horizontal directions simultaneously, the movement of all axes is controlled by either the vertical movement control circuit or the horizontal movement control circuit, as claimed in claim 1. The robot control device described.