Angle measuring method and angle measuring system

Patent metadata

Field	Value
Publication number	US-9134145-B2
Application number	US-201313856061-A
Country	US
Kind code	B2
Filing date	Apr 3, 2013
Priority date	Apr 3, 2013
Publication date	Sep 15, 2015
Grant date	Sep 15, 2015

Abstract

An angle measuring system including: a rotary encoder including an encoder main body and a rotating shaft which is freely rotatable with respect to the encoder main body, the rotary encoder which detects a relative rotation angle of the rotating shaft with respect to the encoder main body; a regulation member which regulates an absolute rotation angle of the encoder main body about the rotating shaft within a fixed range; an absolute angle detecting device which detects the absolute rotation angle of the encoder main body about the rotating shaft concurrently with detection of the relative rotation angle by the rotary encoder; and a correction device which corrects the rotation angle detected by the rotary encoder based on the rotation angle detected by the absolute angle detecting device.

First claim

What is claimed is:

1. An angle measuring system comprising:
a rotary encoder including an encoder main body and a rotating shaft which is freely rotatable with respect to the encoder main body, the rotary encoder which detects a relative rotation angle of the rotating shaft with respect to the encoder main body;
a regulation member which regulates an absolute rotation angle of the encoder main body about the rotating shaft within a fixed range;
an absolute angle detecting device which detects the absolute rotation angle of the encoder main body about the rotating shaft concurrently with detection of the relative rotation angle by the rotary encoder; and
a correction device which corrects the rotation angle detected by the rotary encoder based on the rotation angle detected by the absolute angle detecting device.

2. The angle measuring system according to claim 1 , wherein the absolute angle detecting device is a non-contact angle detecting device which detects the rotation angle without contact with the encoder main body.

3. The angle measuring system according to claim 2 , wherein the non-contact angle detecting device is a one which uses a laser interferometer.

4. The angle measuring system according to claim 1 , wherein the regulation member includes a weight member which urges a reference position of the encoder main body downward in a gravity direction.

5. The angle measuring system according to claim 2 , wherein the regulation member includes a weight member which urges a reference position of the encoder main body downward in a gravity direction.

6. The angle measuring system according to claim 3 , wherein the regulation member includes a weight member which urges a reference position of the encoder main body downward in a gravity direction.

7. An angle measuring method using a rotary encoder including an encoder main body and a rotating shaft which is freely rotatable with respect to the encoder main body, the rotary encoder which detects a relative rotation angle of the rotating shaft with respect to the encoder main body, the angle measuring method comprising:
regulating an absolute rotation angle of the encoder main body about the rotating shaft within a fixed range;
detecting the absolute rotation angle of the encoder main body about the rotating shall concurrently with detection of the relative rotation angle by the rotary encoder; and
correcting the rotation angle detected by the rotary encoder based on the detected absolute rotation angle.

Assignees

• Shimizu Toru
• Tokyo Seimitsu Co Ltd

Inventors

• Shimizu Toru

Classifications

• G01D5/30

  the beams of light being detected by photocells · CPC title

• G01D5/266 Primary

  by interferometric means (G01D5/353 takes precedence) · CPC title

• G01D5/24485

  using other sensors · CPC title