Synthesis of a novel linear-rotary electromagnetic induction sensor using printed circuit coils

Encoders and resolvers are the commonly used sensors to measure the shaft position in motion control applications. Requirements of precise manufacturing and special electromagnetic or optic structures make those sensors expensive. Reduction of cost without degradation of performance is a challenging problem in sensor design. It demands novel and innovative designs to be explored. This paper presents the synthesis of a novel linear-rotary electromagnetic induction sensor using printed circuit coils. The operating principle of the new sensor adapts that of a resolver but the new sensor outputs have a piece-wise linear relationship with the shaft position. In this work, systematic design procedures are described and the prototypes are fabricated. Evaluation of the prototypes shows that the new sensor achieves the accuracy comparable to the accuracy of industrial resolvers.