JPH03216712A - Servo controller - Google Patents

Abstract

PURPOSE:To always attain highly precise servo control by automatically correcting an offset speed when positioning is completed. CONSTITUTION:When a positioning completion detection means 35 detects the completion of the positioning of a body to be driven 12, an offset speed arithmetic means 37 calculated the offset speed based on the deviation of the positioning command position of the body to be driven 12 and a present position, and the gain of servo control. The calculated offset speed is temporarily stored in a storage means 40 and the stored offset speed is added to a speed command calculated at the time of a positioning processing. Thus, accurate servo control is always attained when positioning is completed since the offset sped is automatically corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a servo control device that automatically corrects offset speed upon completion of positioning.

(Prior art) The configuration of a commonly used servo control device is
It is as shown in the figure.

A slide unit 12 is connected to the servo motor 10 via a ball screw 11. The slide unit 12 moves in the left and right directions shown by the arrows as the servo motor 10 rotates. The servo motor 10 is provided with a tacho generator 15 that outputs a voltage according to its rotation speed, and a pulse generator 16 that outputs a pulse for each unit rotation angle. The tacho generator 15 is connected to the servo amplifier l8 and is used for speed feedback of the servo motor 10. The pulse generator 16 is connected to the positioning processing section 20 and the differential processing section 25, and is used for feedback of the speed signal of the servo amplifier 18.

The positioning processing section 20 outputs a speed command signal to the servo amplifier 18 according to the distance between the input command position and the current position specified by the pulse from the pulse generator 16. On the other hand, the differential processing section 25 differentiates the pulse output from the pulse generator 16 and outputs the result to the offset speed calculation section 27 . The constant speed processing unit 29 outputs a speed signal for driving the servo motor 10 at a constant speed to the servo motor 10 or the offset speed calculation unit 27, respectively, based on the manually input command speed. The switch 30 is used to select the speed signal to be output to the servo amplifier 18 when performing positioning control and when performing constant speed control. That is, when performing positioning processing, this switch 30 is set to the position shown in the figure, and the servo amplifier 18 receives the speed signal output from the positioning processing section 20 and the speed signal output from the offset speed calculation section 27. A speed signal superimposed with the above is output. Further, when constant speed processing is performed, the switch 30 is switched to the constant speed processing section side, and only the speed signal output from the constant speed processing section 29 is sent to the servo amplifier 18.
is input.

As above. A conventional servo amplifier control device having the configuration generally operates as follows.

First, during positioning processing, the switch 30 is set to the position shown in the figure, and when a command position is input to the positioning processing section 20, a speed signal corresponding to the distance to the command position is output to the servo amplifier 18. The servo amplifier 18 is
An output corresponding to this speed signal is output to the servo motor 10. This causes the servo motor 10 to rotate, the ball screw 11 to rotate, and the slide unit 12 to start moving in either the left or right direction. The rotation speed of this servo motor 10 is detected by a tacho generator 15,
It is fed back to the servo amplifier 18. At the same time, the pulses output from the pulse generator 16 are input to the differential processing section 25, and the offset speed calculation section 27 calculates the differential with the speed signal output from the constant speed processing section 29 according to the input command speed. The offset speed calculated based on the signal output from the processing unit 25 is output,
This offset speed and the speed signal output from the positioning processing section 20 are superimposed and output to the servo amplifier 18. Therefore, the servo motor 10 operates faithfully to the speed signal output from the positioning processing section 20.

Thereafter, when the rotational speed of the servo motor 10 becomes stable, the control is switched to constant speed control, and at this time, the position of the switch 30 is switched to the constant speed processing section side. When the switch 30 is switched to such a position, the constant speed processing section 29
The speed signal output from the servo amplifier 18 is directly inputted to the servo amplifier 18, and the servo motor 10 rotates at a speed corresponding to this speed signal.

(Problem to be Solved by the Invention) However, in such a conventional servo control device, the calculation of the offset speed described above must be performed while the servo motor 10 is rotating at a constant speed. In order to always obtain a stable offset speed over time, it is necessary to perform the above operations periodically.

Further, since it is practically impossible to perform such an operation while the servo control device is in operation, it is necessary to separately perform the operation for determining the offset speed.

The present invention was made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a servo control device that automatically corrects offset speed.

(Means for Solving the Problems) To achieve the above object, the present invention includes a positioning completion detection means for detecting the completion of positioning of a driven body, and a deviation between a positioning command position and a current position of the driven body. an offset speed calculation means for calculating an offset speed during servo control based on the gain of the servo control; and storage means for temporarily storing the offset speed.

(Operation) The servo control device of the present invention configured as described above operates as follows.

When the completion of positioning of the driven object is detected by the positioning completion detection means, the offset speed calculation means calculates the offset speed based on the deviation between the positioning command position and the current position of the driven object and the gain of the servo control. . This uncalculated offset speed is temporarily stored in the storage means. This stored offset speed will be added to the speed command calculated during the positioning process.

Therefore, the ideal offset speed is always calculated,
Also, since that offset speed will be used,
Extremely accurate servo control can be performed at all times.

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

FIG. 1 is a schematic configuration diagram of a servo control device according to the present invention,
FIG. 2 is an operation flowchart of the apparatus shown in FIG.

Common members in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

The connection relationship and operation of the servo motor 10, tachogenerator 15, and servo amplifier 18 are the same as those shown in FIG.

The pulse generator 16 is connected to a positioning processing unit 35, and the positioning processing unit 35 outputs a speed signal to the servo amplifier 18 according to the distance between the manually input command position and the current position output from the pulse generator 16. do. Further, the positioning processing unit 35 outputs the deviation ε between the command position and the current position and the gain G during positioning processing to the offset speed calculation unit 37. The offset speed calculating section 37 calculates the V. ■＝ε・G
Calculate the offset speed V0. The offset speed calculated in this way is usually calculated by the latch section 40.
The signal is superimposed on the speed signal output from the positioning processing section 35 and output to the servo amplifier 18.

The positioning processing unit 35 determines that positioning is complete when the command position and the current position become equal, and at this time a latch signal is output to the latch unit 40, which causes the latch unit 40 to perform the offset speed calculation unit. The offset speed output from 37 is temporarily stored. In addition, the positioning processing section 3
Reference numeral 5 constitutes positioning completion detection means, offset speed calculation section 37 constitutes offset speed calculation means, and latch section 40 constitutes storage means.

The servo control device of the present invention constructed as described above operates as follows according to the operation flowchart shown in FIG.

First, after the command position is input to the positioning processing section 35,
Until the slide unit 12 moves to this command position, the positioning processing unit 35 calculates a speed command value according to the deviation between the command position and the current position, and the servo amplifier 18
(Step 10.11). At this time, the offset speed calculation unit 37 calculates the offset speed V0, .
This offset speed and the speed signal output from the positioning processing section 35 are output to the servo amplifier 18, and the servo motor 10 rotates at the rotation speed specified by these signals (step 12). When such control is performed and the positioning processing section 35 detects the completion of positioning (step 10), the offset speed calculation section 37 calculates the offset speed at that time and sends the offset speed to the latch section 40. is stored (step 13.14).

The offset speed stored in this way is output to the servo amplifier 18, but since this offset speed is the one when positioning is completed, it acts to stop the servo motor 10. . In other words, when positioning is completed, it is desirable that a signal that causes the rotation of the servo motor 10 to stop, that is, a speed signal of 0, is output from the positioning processing unit 35. However, in reality, the influence of aging and ambient temperature It does not become completely 0. Therefore, if this deviation is compensated for by the offset speed, a completely zero speed signal will be output to the servo amplifier 18. This also applies when the servo motor is rotated at an extremely low speed. This offset speed latching is automatically performed every time position control is performed, so it is possible to completely compensate for offset speed fluctuations due to uncertain factors, ensuring high rotational speed accuracy and positioning accuracy at all times. You can keep it accurate.

(Effects of the Invention) As is clear from the above explanation, according to the present invention, it is possible to automatically correct the offset speed upon completion of positioning, so that fluctuations in the offset speed due to uncertain factors can be completely compensated for. This means that rotational speed accuracy and positioning accuracy can always be maintained at a high level of accuracy.

[Brief explanation of drawings]

Fig. 1 is a schematic configuration diagram of a servo control device according to the present invention, Fig. 2 is an operation flowchart of the device shown in Fig. 1, and Fig. 3 is a diagram of a conventionally commonly used servo control device. It is a schematic block diagram. 0... Servo motor, 2... Slide unit (driven object), 8... Servo amplifier, 5... Positioning processing unit (positioning completion detection means), 7... Offset speed calculation unit (offset Speed calculation means) 0... Latch section (memory means).

Claims (1)

[Claims] Positioning completion detection means for detecting the completion of positioning of a driven object; and an offset speed during servo control based on the deviation between the positioning command position and the current position of the driven object and the gain of the servo control. It is characterized by comprising an offset speed calculation means for calculating, and a storage means for temporarily storing the offset speed calculated by the offset speed calculation means when the positioning completion of the driven body is detected by the positioning completion detection means. servo control device.