A Rod-type Passive and Wireless Torque and Bending Moment Sensor Working in a Self-decoupled Mode

A rod-type passive and wireless torque and bending moment sensor working in a self-decoupled mode was proposed, analyzed, fabricated, and tested. The sensor was mainly composed of a torque deforming sheet, a bending moment deforming sheet and several rods. The self-decoupling was achieved through mechanical arrangement by providing two locations where the strain depended either only on the torque or only on the bending moment (irrespective of its direction). Two pieces of magnetostrictive material were pasted on the torque deforming sheet and the bending moment deforming sheet to sense the independent strain. Finite element method (FEM) analysis was carried out to verify the self-decoupling working principle. The passive and wireless characteristic were fulfilled based on the Villari effect. Experiments were conducted to test the performance of the sensor. Experimental results showed that the sensor had excellent self-decoupling ability, with an error less than 1.31%. The sensor worked dynamically with an error less than 1.54%. Furthermore, the sensor showed merits of working passively and wirelessly. All these merits mean the sensor has potential applications in cutting tools, sealed gear boxes, etc.