A New Arrangement Method of Receiving Coils for Long-Range Magnetostrictive Position Sensor

Magnetostrictive position sensor (MPS) utilizes the Wiedemann effect and inverse effect to implement the excitation and reception of torsional waves in a waveguide, thereby the position of the cursor is determined by the time-of-flight (ToF). Generally, the torsional wave is received by the detection device fixed at the end of waveguide. To expand the measuring range and enhance the signal intensity, a new structure based on distributed receiving coils (DRCs), and a new model of dual ToF reception are proposed in this article. Multiple receiving coils (RCs) are arranged in DRC structure, and torsional waves are received by neighboring RCs, which shortens the propagation distance of the wave. After the analysis of the DRC work principle, a torsional signal reception model is presented. The validation and reliability of the proposed strategy are verified by experiments. Finally, the undetectable area (UA) of DRC and the limit of arrangement of RCs are discussed in detail. Testing results indicate that the measuring range is expanded 2.9 times to 3.43 m.