Intelligent compensation method of Moire fringe orthogonality deviation

A new method and its implementation are put forward to compensate the orthogonal deviation of the Moire fringe in photoelectrical encoder, in which the orthogonal deviation of Moire fringe at each period is measured by correlation function analysis. In order to make the sampled signal uniform, a frequency-change sampling algorithm is proposed based on the coarse code of the encoder. And the compensating parameters could be updated adaptively by switching the modes to reduce the error ratio of the encoder caused by the severe environment. Experiment results show that, when the orthogonal deviation is within 10 degrees, after compensation the orthogonality of the signal increases by 93%.