Two-dimensional absolute displacement encoder

Abstract

The present invention discloses a two-dimensional absolute displacement encoder, which comprises a light path system and an FPGA signal processing system. The light path system comprises a parallel light source, a two-dimensional absolute encoding code channel, an imaging lens group, an aperture diaphragm and an image sensor. The two-dimensional absolute encoding code channel is placed on a to-be-measured plane, and is composed of code elements the same in size and encoded in the pseudo random coding mode, wherein the code elements are capable of reflecting the light or not capable of reflecting the light. The FPGA signal processing system mainly conducts the FPGA realization for the configuration of the image sensor, the reading of the image information, the median filtering and binarization treatment of images, the image cache, the code identification, the decoding algorithm and the like. Meanwhile, the FPGA signal processing system realizes the output of two-dimensional absolute position measurement values. The two-dimensional absolute displacement encoder has the advantages of simple structure and strong real-time property. The two-dimensional absolute displacement encoder can quickly decode and output a two-dimensional absolute position measurement value. The two-dimensional absolute displacement encoder can be widely applied to the absolute positioning and the precision measurement of a two-dimensional workbench and has a good practical application prospect.

Description

technical field [0001] The invention relates to the field of precision measurement, in particular to a two-dimensional absolute displacement encoder. Background technique [0002] Grating sensors are widely used in modern precision measuring instruments, CNC machine tools, lithography machines, ultra-finishing and other fields, and are typical measurement equipment for modern precision testing. In practical application, the traditional metrology grating has no zero mark, and the current relative position information is obtained by calculating the increment number from the set zero point during measurement. If the original measurement result is lost due to shutdown and other reasons during the measurement process, it must be searched again. Zero-sum measurement. In order to solve the problem of incremental grating resetting and homing, this patent uses a grating that contains absolute position information codes. When starting up, the absolute grating scale reads the current ...

AI Technical Summary

Problems solved by technology

However, the accuracy of clamping and positioning of this system has a great influence on the measurement of two-dimensional plane motion. The Abbe error is often caused to reduce the accuracy of measurement results during installation and positioning. At the same time, the measurement system composed of this measurement method occupies a large space. For some Difficulty in small space measurement and inconvenience to measurement

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