Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Optical encoder with misalignment detection and adjustment method associated therewith

A technology for optical encoders and shaft measurement, applied in the field of optical encoders, can solve problems such as the detection of the amount of rotation that has not been proposed, and achieve the effect of easy adjustment

Active Publication Date: 2012-08-01
MITUTOYO CORP
View PDF8 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in said patent reference, the detection of the amount of rotation in the yaw (Yaw) direction in a stationary state is not proposed

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Optical encoder with misalignment detection and adjustment method associated therewith
  • Optical encoder with misalignment detection and adjustment method associated therewith
  • Optical encoder with misalignment detection and adjustment method associated therewith

Examples

Experimental program
Comparison scheme
Effect test

no. 1 example

[0038] Next, an optical encoder according to a first embodiment of the present invention will be described in detail with reference to the drawings.

[0039] figure 1 is a view showing the optical encoder of the first embodiment of the present invention. The optical encoder of the first embodiment of the present invention includes: a scale 1 in which a reflection type diffraction grating is formed at a predetermined pitch in the measurement axis direction; and a probe 2 opposed to the surface of the scale 1 forming the diffraction grating through a predetermined gap, And it can move relative to the scale 1. The probe 2 is connected to a signal processing device 4 via a cable 3 .

[0040] Figure 2A and 2B is a schematic diagram showing the probe 2 in the above optical encoder. In this embodiment, the cable 3 is constituted by bundling a plurality of optical fibers together. The cable 3 is constituted by bundling together six receiving optical fibers 221 around the light ...

no. 2 example

[0073] In the first embodiment, the Lissajous radius R of the quadrature differential signal A, B or the square value of the radius R 2 Serves as attitude monitoring signal MY for yaw direction. For example, in the second embodiment, the Lissajous radius R is approximated to the characteristic function, and the inverse or differential function of the characteristic function is used. This can improve adjustment resolution.

[0074] For example, if Figure 10 As shown, the relationship between the rotation angle and the size of the Lissajous radius can be approximated by Gaussian. Therefore, when using the logarithm of the inverse function, the adjustment resolution in the region of the yaw rotation angle in the vicinity of 0.0° (near the best alignment) is improved.

[0075] Therefore, if Figure 11 As shown, an inverse function conversion block 79 that performs an inverse function conversion on the Lissajous radius R is arranged in the AGC / yaw detection circuit 70, and the...

no. 3 example

[0085] Figure 13 It is a diagram showing an example in which arithmetic processing is realized by software using a microcomputer or a PC.

[0086] That is, the signal processing device 4 includes an A / D conversion unit 80 and a calculation circuit 90 instead of the phase detection circuit 40 , pitch detection circuit 60 , roll detection circuit 50 and AGC / yaw detection circuit 70 . The calculation circuit 90 is connected to the external PC 10 .

[0087] The A / D conversion unit 80 converts the phase signals Sa, Sab, Sb, Sbb, and attitude monitor signals Sz, Szb into digital signals, and supplies the digital signals to the calculation circuit 90 . The calculating circuit 90 calculates the quadrature difference signals A, B, the attitude monitor signals MP, MR, the normalized quadrature difference signals VA, VB, the Lissajous radius R, etc. from the phase signal and the attitude monitor signal converted into digital signals, and provide them to PC 10 . Alternatively, the pha...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

An optical encoder includes a scale having diffraction gratings formed at predetermined pitches in a measurement axis direction, a detection head relatively movable with respect to the scale, the detection head including a light source portion configured to irradiate the scale with light, and a plurality of receiver portions configured to receive light reflected by or transmitted through the diffraction gratings of the scale, at different phases, and a signal processing device configured to perform signal processing to light reception signals output from the receiver portions of the detection head, to produce quadrature differential signals. The signal processing device is configured to calculate alignment adjustment monitor signals corresponding to a Lissajous radius of the quadrature differential signals in order to detect misalignment of the detection head with respect to the scale.

Description

technical field [0001] The invention described herein relates to the field of optical encoders, and misalignment detection and adjustment methods associated therewith. Background technique [0002] An optical encoder using a linear scale with a diffraction grating is known as one of this type of optical encoder. In such an optical encoder, coherent light emitted from a light source is diffracted by a linear scale, and interference fringes having positional information are generated. When phase detecting interference fringes, the length in the direction along the scale can be measured (see Patent Reference 1). Traditionally, in this type of optical encoder, misalignment of the probe is performed by adjusting the relative positional relationship between the probe and the scale while moving the probe along the scale and observing the output Lissajous signal Adjustment. In this case, regarding a probe having a relatively large size, the mechanical reference of the scale can b...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01D5/38G01D18/00
CPCG01D5/24457G01D5/38
Inventor 高桥知隆
Owner MITUTOYO CORP
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com