Abstract
Modeling and control of a rotary actuator based on shape memory alloy (SMA) wires are analyzed theoretically. The heat model and force model of the actuator is given in transfer form. A new model, well descriptive of hysteretic phenomenon between the internal variable, known as Martensite fractions(%) of SMA and stress, as well as temperature is given and written in S-function, which was integrated into Matlab/Simulink. The dynamic response under square waveform and sinusoidal signals are analyzed. In view of nonlinearity and complex parameters in SMA actuator, a classic control strategy and simple PWM is hard to implement in the SMA-based actuator system, the robust controllers based on fuzzy theory are proposed. The strategies of controller with Fuzzy gains self-tuning method and Fuzzy-PID control and normal PID are compared. Numerical simulation demonstrates that the fuzzy self-adaptive is a good choice that can be applied to practical system.
