The Spindle Rotation Error Measurement And Analysis Of Encoder Based On Machine Vision

With the rapid development of industrial technology and improvement of the manufacturing industry in China, more requirements about encoder have been applied for industry, medicine and aviation. As the key components of the measure and control system, encoder resolution and counting accuracy will straightly influence the precision of the measure and control system. Encoder shaft system is the most important part of an encoder in the procedure of production, it can prop up the coded disc and rotate it and then it happens related rotation between disc and the gap. Then it forms moire fringe which helps form the transition of the photoelectric signal. Currently the research of spindle rotary encoder error detection and the influence of the error of the encoder accuracy of spindle were rare, so we need do deep research of encoder shaft to improve the accuracy of the encoder.This paper studied the principle of traditional measuring method of shaft and error separation method, it provide a method based on machine vision detection encoder error of spindle which is different from traditi onal measurement method because it didn't use standard ball or standard rod but Local image acquisition encoder grating instead. This method cancel the error separation procedure in which the measurement of standard ball or par will bring the shape and installing errors. So the inspection process is more simple, rapid and the results are more accurate.According to the method mentioned above, the paper proceeded the spindle rotary error evaluation in roundness error and set up the encoder error of spindle experiment table with CCD camera, fixed times lens, light, electric three-dimensional translation units and encoder fixtures. The paper indicated the filtering denoising, the adaptive threshold segmentation and connected region extraction pretreatment for the circle encoder grating images. This paper uses three times the improved morphological gradient interpolation algorithm to do the edge detection and compare it with the common edge detection method and then evaluate the usability.The last part of the paper use an optimization of the least squares method to evaluate errors and analyze the encoder shaft errors data under different rotate speed and then evaluate the whole errors of the encoder shaft; At the same time, this paper uses WT to do the spectrum analysis for the whole rotate errors of the encoder and separate the precision errors of the encoder shaft and discuss the affects of the whole encoder. This paper not only provided an encoder shaft rotation errors measurement, but also provided the accordance for electricity encoder error precision. It has a significance for develop the encoder.