An absolute grating ruler and displacement measuring method

Abstract

The embodiments of the invention disclose an absolute grating ruler and a displacement measuring method. The absolute grating ruler includes a light source, a lens group, a signal processor and an image sensor array. After collimating and focusing a light beam emitted by the light source, the lens group emits the light beam to the image sensor array. The image sensor array collects light information, converts the light information into electricity information and sends the electricity information to the signal processing module. The signal processor carries out analog-to-digital conversion onthe electricity information to get the gray value of each photosensitive element in the image sensor array, and selects the maximum gray value from the gray values, wherein a target photosensitive element position corresponding to the maximum gray value is a target spot position. The signal processor obtains the position value of a target photosensitive element according to a pre-stored order of the image sensors and the arrangement information of the photosensitive element in each image sensor, and calculates the absolute position measured value of a target spot according to the position value of the target photosensitive element. The image sensor array is used to replace an absolute code path, which saves the manufacturing cost and improves the measurement accuracy and response speed.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to an absolute grating ruler and a displacement measurement method. Background technique [0002] With the development of optical technology, optical measurement technology has also been developed rapidly. Since the absolute grating ruler does not need to find the reference origin, the position can be measured any time the power is re-energized after the power is turned off, and there is no need to return to zero. The application of the absolute grating ruler as a position measurement tool in the machining industry is becoming more and more The wider the range, the performance of the absolute grating scale directly affects the quality of machining. [0003] Absolute grating scales can be divided into absolute circular grating scales and absolute grating scales. The former is a grating scale used to detect the motion state of a rotary body, and the latter is a grating sc...

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Problems solved by technology

[0004] The existing absolute grating scales all have absolute code gratings, and the manufacturing error of the absolute code gratings directly leads to the measurement accuracy of the entire absolute grating scale, which in turn affects the quality of the entire machining process; After the raster signal of the absolute code track, it needs to be processed by analog-to-digital conversion, binarization, decoding, etc. The time period of signal processing is long, resulting in long measurement time and low response speed

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