Research on Combinatorial-Code Grating Eddy-Current Absolute-Position Sensor

For the shortage of the low coarse localization accuracy of phase-difference grating eddy-current sensor (PDGECS), a combinatorial-code GECS (CCGECS) is presented in this paper. CCGECS adopts a single-track code localization method to realize the coarse localization of the sensor coils of GECS, which has replaced the multitrack phase-difference localization method of PDGECS. In this paper, the measurement principle, the coding and code recognition method, the coarse localization accuracy, and the design of CCGECS are introduced; at last, the calculation method of the absolute position of the sensor coils is concluded. Experimental results show that adoption of a single-track code localization method to realize the coarse localization greatly improved the coarse localization accuracy of GECS, avoided the possibility of the appearance of gross error of measurement results, resolved the contradiction between the coarse localization accuracy and the measurement range caused by adoption of the multitrack phase-difference localization method, realized the absolute-position measurement to larger range, and, at the same time, reduced the technology requirements.