JPH06339882A - Control device for industrial robot - Google Patents

Abstract

PURPOSE:To shorten process time for intermittent operation irrespective of a posture and the operational direction of an arm of an industrial robot. CONSTITUTION:When creation of an operation program is finished, an acceleration-deceleration operation part 25 calculates generating torque of a joint 13 and a load applied to an arm 12 with every operation in the operation program, and carries out operation on the optimal acceleration deceleration. This is stored in a ROM 3. The acceleration-deceleration is read out from the ROM 3 with every operation, and according to this, an acceleration- deceleration pattern is created and outputted, and is supplied to a robot 11 through an amplifier 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling the movement of an arm or the like of an industrial robot according to an acceleration / deceleration pattern.

[0002]

2. Description of the Related Art FIGS. 4 to 7 are views showing a conventional controller for an industrial robot. FIG. 4 is an overall configuration diagram, FIG. 5 is a speed control block diagram, FIG. 6 is an acceleration / deceleration pattern characteristic diagram, and FIG. 7 is a control operation flowchart.

In FIG. 4, (1) is a control section of a robot constituted by a computer, a CPU (2), a ROM (3) storing a program for operating the robot, a RAM (4) storing data, It has an interface (hereinafter referred to as I / F) (5) between the peripheral device and the control unit (1) and a servo I / F (6) for outputting a control signal to the robot.

(7) is a teaching box for operating the robot as the peripheral equipment, (8) is a CRT for displaying data and the like, and (9) is a keyboard for inputting data and the like, respectively. / F (5). (10) is connected to the servo I / F (6), and the control unit (1)
An amplifier for amplifying the control signal output from the robot, (11) is a robot connected to the amplifier (10), and has an arm (12) and a joint (13) for driving the arm (12) as its operating part. is doing.

FIG. 5 corresponds to the servo I / F (6) shown in FIG. 4, where * ω is a speed command value, ω is the actual speed of the motor (17), and (15) is a speed command value *. A speed control unit that inputs a deviation between ω and the actual speed ω and outputs a current command value * I so that the deviation becomes zero, in other words, the actual speed ω becomes equal to the speed command value * ω. .

In (16), the deviation between the current command value * I and the current value I is input, and the voltage is adjusted so that the deviation becomes zero and the current value I becomes equal to the current command value * I if ventilation is performed. In the current control unit that outputs a value, this voltage value is amplified by the amplifier (10) and supplied to the motor (17), and the current flowing through the motor (17) is detected by the current sensor (18) and the current value I Will be returned.

The conventional controller for the industrial robot is constructed as described above, and the motor (17) is speed-controlled according to the speed command value * ω by the circuit shown in FIG. This speed command value * ω has a trapezoidal acceleration / deceleration pattern A as shown in FIG.

The robot (11) performs a predetermined series of operations in accordance with an operation program stored in the ROM (3).
This operation is one of several operations in which the tip of the arm (12) moves from point A to point B. This operation program is created by the keyboard (9) and the teaching box (7). Then, the speed control of the movement operation of the arm (12) is executed based on the operation flowchart shown in FIG.

First, in step (21), a speed command value * ω is created according to a trapezoidal acceleration / deceleration pattern. Then step
At (22), the voltage value is output from the servo I / F (6) based on the speed command value * ω. Then, in step (23), it is judged whether or not the movement operation of the arm (12) is completed, and if completed, this processing ends. If not completed, the process returns to step (21) and steps (21) to (23) are repeated.

As described above, the robot (11) is controlled according to the acceleration / deceleration pattern having a constant acceleration / deceleration. In the robot (11), the torque generated by the joint (13) and the load applied to the arm (12) vary depending on the posture and the moving direction of the arm (12). Therefore, the acceleration / deceleration is set so that the maximum value of the torque generated by the joint (13) and the maximum value of the load applied to the arm (12) are below the allowable values in all postures and movement directions of the arm (12). I have decided.

[0011]

In the conventional controller for the industrial robot as described above, the acceleration / deceleration of the moving operation is
Since it is determined based on the maximum value of the torque generated by the joint (13) and the maximum value of the load applied to the arm (12), the arm (12)
Problems may occur depending on the posture and the direction of movement of the.

That is, the torque generated by the joint (13) and the arm (1
The time required to move the arm (12) is controlled by the acceleration / deceleration pattern consisting of a constant acceleration / deceleration time, even though the load applied to 2) is small and the control is possible according to the acceleration / deceleration pattern of larger acceleration / deceleration. There is a problem that (tact time) becomes longer than necessary.

The present invention has been made in order to solve the above-mentioned problems, and is irrespective of the posture and movement direction of the arm.
An object of the present invention is to provide a control device for an industrial robot that can reduce the tact time.

[0014]

The industrial robot control apparatus according to the present invention ensures that the torque generated by the joint and the load applied to the arm are within the permissible value for each moving operation instructed by the operation program. In addition, it is provided with a pattern generation means for generating an acceleration / deceleration pattern based on a preset acceleration / deceleration.

[0015]

In the present invention, since the acceleration / deceleration pattern is generated and the speed is controlled for each moving operation, the acceleration / deceleration is increased if the torque generated by the joint and the load applied to the arm are small, and vice versa. When the load increases, the acceleration / deceleration can be reduced.

[0016]

1 to 3 are views showing an embodiment of the present invention, FIG. 1 is an overall configuration diagram, FIG. 2 is a control operation flowchart, and FIG. 3 is an acceleration / deceleration pattern characteristic diagram, similar to the conventional device. The same parts are denoted by the same reference numerals. Note that FIG. 5 is also used in this embodiment.

In FIG. 1, reference numeral (25) is an acceleration / deceleration calculating section for calculating the torque generated by the joint (13) and the load applied to the arm (12) and calculating the optimum acceleration / deceleration. Other than this, it is similar to FIG.

When the operation program has been created,
The acceleration / deceleration calculation unit (25) calculates the generated torque of the joint (13) and the load applied to the arm (12) for each operation in the operation program, and calculates the optimum acceleration / deceleration. Then, the calculated acceleration / deceleration is stored in the ROM (3).

Next, the operation of this embodiment will be described with reference to FIG. First, in step (27), the optimum acceleration / deceleration for the movement operation instructed by the operation program is stored in ROM.
Read from (3). Then, with the read acceleration / deceleration,
As described above, the acceleration / deceleration processing is performed according to steps (21) to (23). This control is executed for each operation in the operation program. It should be noted that (21) and (22) constitute pattern generation means.

The acceleration / deceleration pattern B at this time is as shown in FIG. 3, and the acceleration / deceleration can be increased as compared with the conventional acceleration / deceleration pattern A. Therefore, the movement time of the arm (12) is shortened.

[0021]

As described above, in the present invention, the acceleration / deceleration pattern is generated and the speed is controlled for each moving operation instructed by the operation program. Therefore, the torque generated by the joint and the load applied to the arm are If it is small, the acceleration / deceleration can be increased, and conversely, if the load is large, the acceleration / deceleration can be decreased, and the takt time of the robot can be shortened.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a control operation flowchart of FIG.

FIG. 3 is a characteristic diagram of an acceleration / deceleration pattern according to the present invention.

FIG. 4 is an overall configuration diagram showing a conventional controller for an industrial robot.

5 is a speed control block diagram of FIG. 4. FIG.

FIG. 6 is an acceleration / deceleration pattern characteristic diagram showing a conventional controller for an industrial robot.

7 is a control operation flowchart of FIG.

[Explanation of symbols]

 1 Robot Control Unit 11 Robot 12 Arm 13 Joint 17 Motor 25 Acceleration / Deceleration Calculation Unit

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] September 8, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006] (16) inputs the deviation of the current command value * I and the current value I, as the difference is such that the zero current value I is equal to the current command value * I if conversion words In the current controller that outputs the voltage value, this voltage value is amplified by the amplifier (10) and supplied to the motor (17), and the current flowing in the motor (17) is detected by the current sensor (18) and the current value I is returned.

Claims (1)

[Claims] 1. A robot apparatus in which a joint and an arm move according to an operation program, and the speed of each move is controlled according to an acceleration / deceleration pattern. In each of the move operations, a torque generated by the joint and a load related to the arm are applied. A control device for an industrial robot, comprising: a pattern generation unit that generates the acceleration / deceleration pattern based on acceleration / deceleration preset to reach a limit of an allowable value.