A new method for reducing hysteresis of torque sensors: Cross magnetic shaking

Cross magnetic shaking, a new method for reducing hysteresis, is proposed for shaft torque sensors based on the magnetostrictive effect of the steel shaft. In this method, an auxiliary magnetic field (shaking field) is superposed perpendicularly to the exciting field while differences in permeabilities along lines of tension and of compression are detected by the field at the shaft surface. Hysteresis measured for a quench-hardened steel shaft of 25 mm diameter under the applied torque from -490 to 490 Nm was reduced by about nine times and sensitivity increased by a factor of 2.