A two-stage model for rate-dependent inverse hysteresis in reluctance actuators

Abstract

Abstract Reluctance actuators, being capable of providing high force densities, have been widely adopted for solving the task of high force applications. However, the strong non-linearity in the inherent hysteresis considerably limits the application performance of reluctance actuator in the output of high-precision force, in particular when hysteresis is coupled with eddy effects which gives rise to a rate-dependent hysteresis effect in the actuator. Feed-forward compensation technologies, which utilize the inverse hysteresis model as the compensator, have been proved to be effective in alleviating hysteresis non-linearities over different excitation frequencies. In the study, a new two-stage model for rate-dependent inverse hysteresis is proposed, which can directly model the inversion of rate-dependent hysteresis regardless of the hysteresis loop is symmetric or not. The proposed model is applied as a feed-forward compensator to linearise the rate-dependent hysteresis effects in the reluctance actuator at a range of excitation frequencies between 1 and 60 Hz. Comprehensive numerical simulations and real-world experiments are implemented on the reluctance actuator to validate the effectiveness of the new model. The results show that the proposed Two-stage hysteresis model can accurately and robustly demonstrate the inversions of rate-dependent hysteresis, and the hysteresis non-linearities in the reluctance actuator are effectively suppressed by the two-stage model-based compensator with less insensitivity to various noise.