JPH056223A - Positioning device - Google Patents

Abstract

PURPOSE:To provide a positioning device with high stability even in an area having the problem of vibrations such as disturbance in the gain of velocity feedback in an extremely low speed state or a stopping state. CONSTITUTION:Difference between the target timing value of position movement from a software processing part 1 and the current position of a counter 10 depending on signals from an encoder 7 to detect the revolution of a motor 6 is amplified by a position loop amplifier 3 and outputted, and speed signals from a speed preparation circuit 8 are amplified by a variable gain speed feedback amplifier 19 and outputted. Difference between both outputs is amplified by a speed loop amplifier 4 and transmitted to a driver 5, and the motor 6 is driven. Thus, the software processing part 1 calculates the level of difference between the current position and the target timing value of the position movement, and the gain of the variable gain speed feedback amplifier 19 is switched to a larger gain when this difference is larger than a fixed value or to a smaller gain when the difference is smaller.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a numerical control positioning device used for industrial robots and the like.

[0002]

2. Description of the Related Art A conventional positioning device will be described with reference to FIG.

Referring to FIG. 3, a conventional positioning device includes a soft processing section 1, a D / A converter 2, a position loop amplifier 3, a speed loop amplifier 4, a driver 5, a motor 6, and a rotation of the motor 6. Encoder 7 for detecting a pulse and outputting a pulse and a pseudo sine wave, a speed creating circuit 8 for creating a speed signal from the output of the encoder 7, and a speed creating circuit 8
2 is composed of a speed feedback amplifier 9 for amplifying the output of 1 and a counter 10 for counting the pulses of the encoder 7 and outputting the current position.

The operation of the conventional positioning device having the above structure will be described below.

First, the software processing unit 1 outputs a timing target value for position movement, and sends the difference from the current position output from the counter 10 to the D / A converter 2.

The D / A converter 2 converts the difference into an analog signal, and the position loop amplifier 3 amplifies it.

The speed creating circuit 8 creates a speed signal from the output of the encoder 7, and the speed feedback amplifier 9 amplifies this speed signal.

The speed loop amplifier 4 calculates the difference between the output of the position loop amplifier 3 which amplifies the difference between the position movement timing target value and the current position, and the output of the speed signal amplified by the speed feedback amplifier 9. Amplify and drive 5
The driver 6 drives the motor 6, and the motor 6
The encoder 7 detects the operation.

By repeating the above operation and feeding back the current position to the position movement timing target value, the current position can be brought closer to the position movement timing target value. Feedback is taken on the position loop amplifier side in order to suppress a sudden change in speed and to suppress vibration due to movement acceleration or disturbance.

[0010]

However, in the above-mentioned conventional configuration, since the resolution of the encoder 7 is limited in the extremely low speed or stopped state, the encoder 7 detects the rotation of the motor 6 in the extremely low speed or stopped state. However, when outputting a pulse and a pseudo sine wave corresponding to that, the output of the encoder 7 is distorted, the S / N ratio is deteriorated, and a signal with a large ripple is generated. Is detected as a moving state at the speed of. Therefore, when the velocity feedback gain is increased, vibration occurs when positioning is stopped. In order to prevent this vibration, there is a problem in that the speed feedback gain cannot be increased and stability against disturbance cannot be increased.

In order to solve the above-mentioned problems, the present invention has a problem in the gain of the velocity feedback in an extremely low speed or in a stopped state, and in the gain of the velocity feedback in a velocity range where there is a problem of vibration due to disturbance or the like. It is an object of the present invention to provide a highly stable positioning device that does not have any problem.

[0012]

In order to solve the above-mentioned problems, the positioning device of the present invention comprises:
The counter detects the current position based on the signal from the encoder that detects the position rotation timing target value and the motor rotation.The difference between the position movement timing target value and the current position is calculated and this difference is detected by the position loop amplifier. Amplified and output, the speed creation circuit creates a speed signal from the signal of the encoder, the gain variable speed feedback amplifier amplifies and outputs this speed signal, and the output of the position loop amplifier and the gain variable speed feedback amplifier A velocity loop amplifier amplifies the difference from the output and sends it to the driver, and in the positioning device configured to drive the motor by the driver, the current position signal from the counter is sent to the soft processing unit, and the soft processing unit Finds the magnitude of the deviation between this current position and the timing target value for the position movement, The gain of the transmission of the feedback amplifier, when this deviation is greater than a certain value for a large gain, when small and switches to a small gain.

[0013]

With the above arrangement, the positioning device of the present invention reduces the gain of the gain variable speed feedback amplifier when the deviation between the target position timing timing value and the current position becomes small during positioning operation immediately before stop. By doing so, even if the speed signal has a large S / N ratio or ripple in an extremely low speed state or a stopped state, a highly stable positioning operation can be performed without being adversely affected, and this position movement due to disturbance or the like occurs. When the deviation between the timing target value and the current position becomes large, the speed feedback effect can be increased by increasing the gain of the gain variable speed feedback amplifier, and a highly stable positioning operation can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the positioning device of the present invention will be described with reference to FIGS.

In FIG. 1, according to the present embodiment, a counter 10 detects the present position by a signal from an encoder 7 which outputs a timing target value for position movement from a software processing unit 1 and detects rotation of a motor. The difference between the movement timing target value and the current position is obtained, this difference is converted to analog by the D / A converter 2, amplified by the position loop amplifier 3 and output, and the speed creation circuit 8 outputs the speed from the signal of the encoder 7. A signal is created and this speed signal is amplified and output by the gain variable speed feedback amplifier 19. The speed loop amplifier 4 amplifies the difference between the output of the position loop amplifier 3 and the output of the gain variable speed feedback amplifier 19. To the driver 5, and when the driver 5 drives the motor 6, the current position signal from the counter 10 is transferred to the software. Feeding the processing section 1, the software processing unit 1
Determines the magnitude of the deviation between the present position and the target value of the position movement timing, and decreases the gain of the gain variable speed feedback amplifier 19 to a large gain when the deviation is larger than a certain value. When I am switching to a small gain.

FIG. 2 is a flow chart of this gain switching operation.

In step # 1, the software processing unit 1
, Finds the deviation between the target value of the position movement timing and the current position.

In step # 2, the software processing unit 1
However, the absolute value of the deviation in step # 1 is compared with a certain constant value P, and if P or less, the process proceeds to step # 3, and if it exceeds P, the process proceeds to step # 4.

In step # 3, the software processing unit 1
However, the gain of the variable gain speed feedback amplifier 19 is switched to small.

In step # 4, the software processing unit 1
However, the gain of the variable gain speed feedback amplifier 19 is switched to a large value.

The positioning device of the present invention is not limited to the above-mentioned embodiment, and various modes are possible. If the gain of the gain variable speed feedback amplifier can be switched to an appropriate value in accordance with the deviation between the position movement timing target value and the current position, the design of each component is free. For example, the switching and control method may be hardware or software.

[0022]

The positioning device of the present invention has a problem that the conventional positioning device cannot have high stability against a disturbance, whereas the positioning target of the position movement and the current position are different from each other. If the magnitude of the deviation is larger than a certain fixed value, the gain of the gain variable speed feedback amplifier is set to a large value, and if the magnitude of the deviation is smaller than a certain fixed value. Has a configuration in which the gain of the gain variable speed feedback amplifier is set small, the gain of the gain variable speed feedback amplifier is reduced when the deviation between the position movement timing target value and the current position becomes small immediately before the positioning is stopped. By making it small, even if there is a large S / N ratio or ripple in the speed signal in extremely low speed or stopped condition, it will not be adversely affected. A highly qualitative positioning operation can be performed, and when the deviation between the timing target value of this position movement and the current position becomes large due to disturbance or the like, the gain of the gain variable speed feedback amplifier is increased to increase the speed feedback effect. There is an effect that it is possible to perform a highly stable positioning operation by increasing the.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a flowchart showing the operation of FIG.

FIG. 3 is a block diagram of a conventional example.

[Explanation of symbols]

 1 Software Processing Unit 3 Position Loop Amplifier 4 Speed Loop Amplifier 5 Driver 6 Motor 7 Encoder 8 Speed Creation Circuit 10 Counter 19 Gain Variable Speed Feedback Amplifier

Claims (1)

Claim: What is claimed is: 1. A soft processing unit outputs a timing target value for position movement, and a counter detects the current position by a signal from an encoder that detects the rotation of a motor. The difference between the value and the current position is calculated, this difference is amplified by the position loop amplifier and output, the speed creation circuit creates the speed signal from the signal of the encoder, and the gain variable speed feedback amplifier amplifies and outputs this speed signal. The speed loop amplifier amplifies the difference between the output of the position loop amplifier and the output of the gain variable speed feedback amplifier, and sends the difference to the driver, and the driver drives the motor. Of the current position signal to the soft processing unit, and the soft processing unit detects the current position and the position movement. It is characterized in that the magnitude of the deviation from the aiming target value is obtained, and the gain of the gain variable speed feedback amplifier is switched to a large gain when the deviation is larger than a certain fixed value and to a small gain when the deviation is small. Positioning device.