Research on Novel Grating Eddy-Current Absolute-Position Sensor

A novel grating eddy-current absolute-position sensor (GECS) that can work in a harsh environment and its low-power measurement system are presented. The designed sensor consists of reflection conductors uniformly arranged on a line and eight corresponding rectangular coils in an array, which can be manufactured by printed circuit board (PCB) technics. Hence, it is easy to realize mass production due to the simple fabrication process. The measurement principle, the design, and the measurement system of GECS are introduced. Experimental results show that the accuracy of the measurement system, which is independent of the moving speed, can reach plusmn0.015 mm in a full scale of 300 mm. The electronic digital caliper based on GECS can be used in liquid medium, such as water, oil, coolant, and so on, and the rating of being waterproof can reach IP67.