JPH09311725A - Method for reducing rotation angle error for planetary gear device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for reducing a rotation angle error appearing on the output side of a planetary gear device with a simple constitution. SOLUTION: In the planetary gear device 2 where an internal gear 21 is fixed and a deceleration rotation is taken out from the carrier 23 of a planetary gear 22. Rotation angle correction data 7 corresponding to the rotation angle of an input shaft 25 where a sun gear 24 is formed is previously stored and the rotation angel of the input shaft 25 is detected by a rotary encoder 8 or the like. The rotation command 5 of a servo motor 1 which rotates/drives the input shaft 25 is corrected based on rotation angle correction quantity corresponding to the detected rotation angle. A fixed component appearing in accordance with the rotation angle, which occupies the most of the rotation angle errors, in the rotation angle errors appearing on the output side of the planetary gear device 2 can be removed. Thus, the rotation angle errors can be reduced with simple constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation angle error reducing method for reducing a rotation angle error transmitted in a drive mechanism for transmitting rotation via a planetary gear device by a simple method.

[0002]

2. Description of the Related Art A planetary gear device is incorporated in various drive mechanisms and is used for decelerating rotation from a motor, which is a high-speed rotation source, and transmitting it to a load side. Also in the rotational force transmission mechanism including the planetary gear device, an error occurs in the rotational angle transmitted like the other rotational force transmission mechanisms. For example, a transmission error occurs in the rotation angle according to a load change, a gear meshing state change, or the like.

In the prior art, for example, the output rotation of the planetary gear device is fed back to detect the phase shift or the like from the input rotation and the detected shift can be eliminated so that the input of the planetary gear device can be eliminated. The rotation command input of the motor that is the rotation source is corrected.

However, there are many fluctuation factors such as the case where the speed ratio of the planetary gear device is not divisible by an integer, and the meshing state of the gears changes due to the load fluctuation. Therefore, overshooting or undershooting occurs in the feedback control. In some cases, the rotation angle error cannot be reduced with good responsiveness.

[0005]

When the planetary gear device is used as a speed reducer, the internal gear is fixed, and the side of the carrier supporting the planetary gear is the output side of the decelerated rotation. Is configured to be. in this case,
The rotation angle error of the output rotation includes a fixed component uniquely determined corresponding to the input rotation angle and other fluctuation components. The fixed component accounts for most of the rotation angle error. Therefore, if we can correct this fixed component,
A rotation angle error can be easily suppressed.

In view of this point, an object of the present invention is to propose a method capable of reducing a rotation angle error of a planetary gear device by a simple method.

[0007]

In order to solve the above-mentioned problems, the present invention is a planetary gear device in which an internal gear is fixed and decelerated rotation is taken out from a carrier of the planetary gear. The rotation angle correction amount corresponding to the formed rotation angle of the input shaft is stored in advance, the rotation angle of the input shaft is detected, and the input shaft is detected based on the rotation angle correction amount corresponding to the detected rotation angle. The rotation command signal of the servo motor that drives the rotation is corrected.

Most of the rotation angle error generated through the planetary gear device is a fixed component which is uniquely determined in correspondence with the rotation angle of the input shaft. Therefore, in the method of the present invention, since this fixed component is corrected based on the rotation angle of the input shaft, most of the rotation angle error can be easily removed. Therefore, if the method of the present invention is used, for example, together with the conventional method of correcting the rotation angle error by the feedback control, the rotation angle error can be reduced or eliminated with high accuracy and responsiveness.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a rotation angle error reducing mechanism to which the method of the present invention is applied. The rotational force transmission mechanism has a servomotor 1 and a planetary gear device 2 connected to the output shaft 1a, and the output of the planetary gear device 2 drives the load 3 side. .

In the planetary gear device 2, an internal gear 21 is fixed, and a carrier 23 of the planetary gear 22 serves as a rotation output element. Further, an input shaft 25 on which the sun gear 24 is formed is connected to the output shaft 1a of the servomotor 1. The driving of the servo motor 1 is controlled by the servo driver 4. That is, the servo driver 4 drives and controls the servo motor 1 based on the input of the rotation command 5.

Here, in order to reduce the rotational angle error appearing on the output side of the planetary gear device 2, an input synchronization component correction circuit 6 is provided. The input synchronization component correction circuit 6 includes a storage unit such as a ROM that stores the rotation angle correction data 7. The stored rotation angle correction data 7 is a set of rotation angle correction amounts uniquely determined in correspondence with the rotation angle of the input shaft 25 of the planetary gear device 2. That is,
The rotation angle error that appears in the output of the planetary gear device 2 includes a fixed component that is determined according to the rotation angle of the input rotation shaft and a fluctuation component that is generated due to other factors. Of these, the fixed component accounts for most of the error. Therefore,
In this example, a fixed component of the rotation angle error is stored in advance, and the rotation command 5 is corrected according to the rotation angle of the input rotation shaft according to the fixed component of the rotation angle error.

In order to detect the rotation angle of the input rotary shaft,
The rotary angle of the servo motor 1 is detected by using the rotary encoder 6. This detected value is input to the input synchronization component correction circuit 6. The input synchronization component correction circuit 6 retrieves and outputs the corresponding rotation angle correction amount from the rotation angle correction data 7 based on the detected rotation angle. This rotation angle correction amount, in other words, the input synchronization component is the servo driver 4
Is supplied to. The servo driver 4 corrects the rotation command 5 based on the supplied rotation angle correction amount, and drives and controls the servo motor 1 based on the correction result.

By driving the servomotor 1 in this way, the fixed component contained in the rotation angle error appearing in the output of the planetary gear device can be removed. Therefore, the rotation angle error can be reduced accordingly. For this reason,
For example, if the rotation angle error appearing in the output of the planetary gear device 2 is fed back to correct the rotation command 5, it is preferable because the rotation angle error can be reduced extremely efficiently and with good responsiveness.

[0014]

As described above, in the method for reducing the rotation angle error of the planetary gear device according to the present invention, attention is paid to the fixed component appearing corresponding to the rotation angle included in the rotation angle error, and the fixed component is stored in advance. The rotation command for driving the motor is corrected based on the fixed component. Therefore, according to the present invention, the rotation angle error can be reduced with an extremely simple configuration.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a method of reducing a rotation angle error of a planetary gear device according to the present invention.

[Explanation of symbols]

 1 Servo Motor 2 Planetary Gear Device 25 Input Shaft 23 Carrier (Output Element) 3 Load 4 Servo Driver 5 Rotation Command 6 Input Synchronous Component Correction Circuit 7 Rotation Angle Correction Data 8 Rotary Encoder

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[Procedure amendment]

[Submission date] August 2, 1996

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

Claims (1)

[Claims] 1. In a planetary gear device in which an internal gear is fixed and decelerated rotation is extracted from a carrier of a planetary gear, a rotation angle correction amount corresponding to a rotation angle of an input shaft on which a sun gear is formed is previously set. To store the rotation angle of the input shaft, correct the rotation command for controlling the drive of the servomotor rotating the input shaft, based on the rotation angle correction amount corresponding to the detected rotation angle. And a method for reducing a rotation angle error.