Hybrid control of magnetically controlled shape memory alloy actuator based on Krasnosel’skii-Pokrovskii model

The hysteresis nonlinearity of the magnetically controlled shape memory alloy (MSMA) actuator exerts a great influence on the positioning accuracy. To effectively alleviate the hysteresis nonlinearity of the MSMA actuator, an inverse Krasnosel'skii-Pokrovskii model is established in the paper. Subsequently, a hybrid control scheme which is composed of a hysteresis inverse model feedforward controller and a PID feedback controller is proposed to further improve the positioning accuracy of the MSMA actuator. A differential evolution algorithm is adopted to tune the parameters of PID controller. The experimental results show that the proposed control scheme is effective for improving the positioning accuracy of the MSMA actuator, and the maximum positioning error rate is 0.55%.