Hybrid control method of magnetically controlled shape memory alloy actuator based on inverse Prandtl-Ishlinskii model

Abstract

The hysteresis nonlinearity of magnetically controlled shape memory alloy actuator is an obstacle in the achievement of high positioning accuracy. To eliminate the influence of hysteresis nonlinearity, a PID hybrid control method which uses the inverse Prandtl-Ishlinskii model as a feedforward controller is proposed in this paper. The PID parameters are searched by particle swarm optimization with cross and heredity function. The simulation results show that when the influence of external disturbance is not considered, the positioning accuracy of open loop control method is 0.67%, and the positioning accuracy of PID hybrid control based on particle swarm optimization is 0.38%; when the influence of external disturbance is considered, the positioning accuracy of open loop control method is 3.29%, and the positioning accuracy of PID hybrid control based on particle swarm optimization is 1.65%. This indicates that the proposed control method can effectively eliminate the impact of hysteresis nonlinearity and external disturbances on the positioning accuracy.