JPH0667720A - Controller for industrial robot - Google Patents

Abstract

PURPOSE:To shorten a process time by controlling optimumly a moving operation of a robot arm in accordance with an attitude of the arm and its operating direction. CONSTITUTION:By adding a fact that a joing is subjected to load fluctuation in accordance with an attitude of an arm and its operating direction, such acceleration and deceleration as the joint torque is generated to the maximum at every combination of the attitude and the operating direction are calculated in advance, and they are set to an acceleration/deceleration setting means 31 from a keyboard 9. in accordance with the attitude of the arm and its operating direction, the set acceleration/deceleration are selected, and by generating an acceleration/deceleration pattern by an acceleration/deceleration pattern generating means 32, a speed command value *omega is generated.

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. 5 to 8 are views showing a conventional controller for an industrial robot. FIG. 5 is a block diagram, FIG. 6 is a speed control block diagram, FIG. 7 is an operation flowchart, and FIG. It is an acceleration / deceleration pattern curve diagram.

In FIG. 5, (1) is a control unit, and CP
It has a U (2), a ROM (3), a RAM (4), an interface (hereinafter referred to as I / F) (5), and a servo I / F (6) for outputting a control signal to the robot. Servo I / F (6)
Is a teaching box for operating the robot
(7), a display (CRT) (8) for displaying data and the like and a keyboard (9) for inputting data and the like are connected. (10) is an amplifier which is connected to the servo I / F (6) and amplifies the control signal, (11) is a robot which is connected to the amplifier (10), and is an arm (12) and a joint that drives this arm (12) It has (13).

FIG. 6 corresponds to the servo I / F (6) of FIG. 5, where * ω is a speed command value, ω is a speed signal of a motor (15) built in the joint (13), and (16) Is an adder that adds the speed command value * ω and the speed signal ω, (17) is a speed control unit that inputs the output of the adder (16) and outputs a current command value, and (18) is the motor (1
5) Current detector that detects current and outputs current signal, (1
9) is an adder that adds the current command value and the current signal, and (20) is a current control unit that inputs the output of the adder (19) and outputs the voltage command value. ) To the motor (15).

The conventional industrial robot controller is constructed as described above, and by operating the keyboard (9) to specify a program, the control unit (1) operates and the robot is controlled.
The joint (13) of (11) is driven to move the arm (12). The control operation is shown in FIGS. 7 and 8.

First, in step (25), a speed command value * ω is created according to the trapezoidal acceleration / deceleration pattern shown in FIG. Then, in step (26), the output to the servo I / F (6) is executed. That is, as shown in FIG. 6, the speed command value *
The deviation between ω and the speed signal ω is calculated by an adder (16).
The speed control unit (17) outputs a torque command value such that the deviation becomes zero as a current command value. The adder (19) outputs a deviation between the current command value and the current signal, and the current controller (20) outputs a voltage command value such that the deviation becomes zero. This voltage command value is amplified by the amplifier (10), drives the motor (15), and causes the arm (12) to move.

At step (27), it is judged whether or not the movement operation of the arm (12) is completed, and if completed, the processing is ended. If not completed, the process returns to step (25) and the above steps are repeated.

By the way, the conventional control of the robot as described above is performed according to an acceleration / deceleration pattern having a constant acceleration / deceleration time. Since the torque generated by the joint (13) of the robot changes depending on the posture and movement of the arm (12), the joint (13) is generated during all the postures and movements of the arm (12) during acceleration / deceleration time. The maximum value of the torque to be applied is determined by the acceleration / deceleration at which the torque of the joint (13) is less than or equal to the allowable torque.

[0009]

In the conventional industrial robot controller as described above, the maximum torque generated by the joint is equal to or less than the allowable torque of the joint during the acceleration / deceleration time of the arm (12). Although it is determined by the acceleration / deceleration, the arm (1
The torque generated by the joint (13) may be small depending on the posture and motion of (2). In this case, although the control is possible according to the acceleration / deceleration pattern of the larger acceleration / deceleration,
The time required to move the arm (12) (hereinafter referred to as takt time) is required because the acceleration / deceleration pattern of the small acceleration / deceleration is such that the maximum value of the torque generated by the joint (13) is less than the allowable torque of the joint (13). There is a problem that it becomes longer than that.

The present invention has been made to solve the above problems, and the movement operation of the arm can always be controlled in accordance with an appropriate acceleration / deceleration acceleration / deceleration pattern, and the tact time can be shortened. An object of the present invention is to provide a control device for a mobile robot.

[0011]

A control device for an industrial robot according to the present invention provides, for each combination with a posture and a motion direction of an arm divided into a plurality of parts in an entire work area,
Acceleration / deceleration storage means for storing the acceleration and deceleration at which the joint produces the maximum torque, and acceleration / deceleration pattern generation means for generating an acceleration / deceleration pattern based on the stored acceleration and deceleration are provided.

[0012]

According to the present invention, the arm is controlled by generating the acceleration / deceleration pattern that maximizes the torque of the joint depending on the posture and the moving direction of the arm. , It can be controlled by changing the acceleration / deceleration.

[0013]

1 to 4 are views showing an embodiment of the present invention, FIG. 1 is a configuration diagram of a main part, FIG. 2 is a plan view of a robot model,
FIG. 3 is an explanatory view of the contents of the ROM, and FIG. 4 is an operation flowchart. 5 and 6 are also used in this embodiment.

In FIG. 1, reference numeral (31) denotes an arm (1) in response to an input from the keyboard (9), as shown in FIG. 3 described later.
Acceleration / deceleration storage means for storing acceleration α and deceleration β corresponding to the combination of posture and movement direction in 2), and (32) generates an acceleration / deceleration pattern based on the stored acceleration α and deceleration β. The acceleration / deceleration pattern generating means outputs the command value * ω to the servo I / F (6).

In FIG. 2, (12A) is the first arm and (12B).
Is the second arm, (13A) is the first joint J ₁ that rotates the first arm (12A) _first , (13B) is the second joint J ₂ that rotates the second arm (12B), and θ ₁ is Turning angle of the first arm (12A), θ ₂
Is the turning angle of the second arm (12B).

In FIG. 3, the movement directions of the arm (12) are four combinations of direction + and direction − for the first joint J ₁ and the second joint J ₂ , respectively. The arm posture represents the motion start angle of the second joint J ₂ , and is divided into postures 1 to n over the entire arm area. In each arm posture, the accelerations α _{11 to} α _1n , α _{21 to} α _2n , α ₃₁ to allow the second joint J ₂ to generate the maximum torque for each combination of arm movement directions.
α _3n , α _{41 to} α _4n , and deceleration β ₁₁ to β _1n , β ₂₁ ~
β _2n , β _{31 to} β _3n , and β _{41 to} β _4n are calculated in advance and stored in the ROM (3).

Next, the operation of this embodiment will be described with reference to FIG. First, step (35) (acceleration / deceleration storage means (31)
The acceleration / deceleration shown in FIG. 3 stored in the ROM (3) is set according to the arm posture and the movement direction before the start of the movement. Next, the steps (25) to (27) similar to the above are executed at the set acceleration / deceleration to control the arms (12A) (12B). The step (25) is the acceleration / deceleration pattern generation means (32).
Equivalent to.

[0018]

As described above, according to the present invention, the arm is controlled by generating the acceleration / deceleration pattern that maximizes the torque of the joint depending on the posture and the moving direction of the arm. When the load is small, the acceleration / deceleration is increased, and conversely, when the load is increased, the acceleration / deceleration is decreased, and the tact time can be shortened.

[Brief description of drawings]

FIG. 1 is a configuration diagram of essential parts showing an embodiment of the present invention.

FIG. 2 is a plan view of a robot model showing an embodiment of the present invention.

FIG. 3 is an explanatory diagram of contents of a ROM showing an embodiment of the present invention.

FIG. 4 is an operation flowchart showing an embodiment of the present invention.

FIG. 5 is a block diagram showing a control device of the present invention and a conventional industrial robot.

6 is a speed control block diagram of the servo I / F of FIG.

FIG. 7 is an operation flowchart showing a conventional controller for an industrial robot.

8 is an acceleration / deceleration pattern curve diagram used for the control of FIG.

[Explanation of symbols]

 3 ROM 11 Robots 12, 12A, 12B Arms 13, 13A, 13B Joints 31 Acceleration / deceleration storage means 32 Acceleration / deceleration pattern generation means

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[Procedure amendment]

[Submission date] May 12, 1993

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In FIG. 5, (1) is a control unit, and CP
It has a U (2), a ROM (3), a RAM (4), an interface (hereinafter referred to as I / F) (5), and a servo I / F (6) for outputting a control signal to the robot . The I / F (5) is connected with a teaching box (7) for operating the robot, a display (CRT) (8) for displaying data and the like, and a keyboard (9) for inputting data and the like. . (Ten)
Is an amplifier that is connected to the servo I / F (6) and amplifies the control signal. (11) is a robot that is connected to the amplifier (10).
It has a joint (13) for driving the arm (12) and this arm (12).

[Procedure 3]

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[0011]

A control device for an industrial robot according to the present invention provides, for each combination with a posture and a motion direction of an arm divided into a plurality of parts in an entire work area,
Set the acceleration and deceleration joint generates a maximum torque
The acceleration / deceleration setting means for setting the acceleration / deceleration pattern and the acceleration / deceleration pattern generating means for generating the acceleration / deceleration pattern based on the set acceleration and deceleration are provided.

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[0014] In FIG. 1, the posture of (31) in response to input <br/> force thus operating program of the specified robot keyboard (9), as shown in FIG. 3 to be described later, the arm (12) Acceleration α and deceleration β corresponding to the combination of
Deceleration setting means for setting, (32) deceleration pattern generating means for outputting a speed command value * omega generates a deceleration pattern with the set acceleration α and deceleration β servo I / F (6) Is.

[Procedure Amendment 5]

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Next, the operation of this embodiment will be described with reference to FIG. First, step (35) (acceleration / deceleration setting means (31)
The acceleration / deceleration shown in FIG. 3 stored in the ROM (3) is set according to the arm posture and the movement direction before the start of the movement. Next, the steps (25) to (27) similar to the above are executed at the set acceleration / deceleration to control the arms (12A) (12B). The step (25) is the acceleration / deceleration pattern generation means (32).
Equivalent to.

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[Explanation of Codes] 3 ROM 11 Robot 12, 12A, 12B Arm 13, 13A, 13B Joint 31 Acceleration / deceleration setting means 32 Acceleration / deceleration pattern generation means

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[Procedure amendment]

[Submission date] October 18, 1993

[Procedure Amendment 1]

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Claims (1)

[Claims] 1. A robot having an arm and a joint for driving the arm, the movement of these being controlled in speed according to an acceleration / deceleration pattern, the posture of the arm divided into a plurality of parts in the entire work area, and the movement of the arm. Acceleration / deceleration storage means for storing the acceleration and deceleration at which the joint generates maximum torque for each combination with the direction, and acceleration / deceleration for generating the acceleration / deceleration pattern by the acceleration and deceleration stored in the storage means. A control device for an industrial robot, comprising: a pattern generating means.