Research On The Compensation Method Of Moiréfringe Signal Deviation Of Photoelectric Encoder

As a high-precision angular displacement measurement sensor,photoelectric encoders are widely used in automation,aerospace,precision manufacturing and other fields.The angle measurement accuracy of the photoelectric encoder mainly depends on the subdivision accuracy of the Moiré fringe signal,but due to the errors in the installation and manufacturing process of the photoelectric encoder,the Moiré fringe signal may be deviated,and the existence of these deviations will affect the photoelectric encoding.The angle measurement accuracy of the instrument is affected.Therefore,it is of great significance to study the Moiré fringe signal compensation technology to improve the angle measurement accuracy of the photoelectric encoder.The research achievements in the field of Moiré fringe signal deviation compensation technology at home and abroad are referenced and summarized.Starting from the generation principle of Moiré fringe signal,The influencing factors that cause the deviation of the Moiréfringe signal and the deviation of the output signal caused by the error of the photoelectric encoder in the installation and manufacturing process are analyzed.The types of deviations of the Moiré fringe signal of the photoelectric encoder and the influence of these deviations on the angle measurement accuracy are studied.According to the characteristics of the Moiré fringe signal and the main error sources,the waveform equation of the Moiré fringe signal is established,the basic principle of the cuckoo search algorithm is introduced,and a parameter identification method of the waveform equation based on the cuckoo search algorithm and the least square method is proposed,using the residual sum of squares between the Moiré fringe signal and the waveform equation with undetermined parameters as the fitness function of the cuckoo search algorithm.The identification of multiple parameters in the waveform equation of the Moiré fringe signal is realized,and the compensation of the sinusoidal deviation,DC components and equal amplitude deviation of the signal is realized by using the relevant parameters obtained by identification.The fundamental wave phase difference obtained by identification is used to establish a look-up table,which realizes the compensation of signal orthogonality deviation.A Moiré fringe signal compensation system is designed to sample and process the output signal of the photoelectric encoder with 1024 lines.After compensation,the peak subdivision error of the Moiré fringe signal is reduced from 61.41 " before compensation to 13.32" after compensation.The experimental results show that the parameter identification method based on the cuckoo search algorithm and the least square method can accurately identify the parameters in the parameter equation of the Moiré fringe signal,and the subdivision accuracy of the photoelectric encoder is significantly improved after compensation.The Moiré fringe signal deviation compensation method can effectively reduce the deviation existing in the Moiré fringe signal and improve the angle measurement accuracy of the photoelectric encoder.