Force Tracking Fuzzy Control of a Shape Memory Alloy Actuator

Strong non-linearity and hysteresis can be detected in the phase transition process of shape memory alloys (SMA). Furthermore, because of the increasing driving frequency, the SMA driver's driving performance changes gradually leading to time variability. To cope with that, this paper designs a fuzzy controller for the nonlinear system which has better control performance and robustness. Experiments of the sinusoidal and step inputs' tracking control are based on the SMA wire-spring system with the fuzzy controller. Compared with the conventional PID controller, the experimental results show that the fuzzy controller designed in this paper has better tracking control property, shorter rise time and fewer overshoot. What's more, the maximum tracking error remains almost unchanged while the driving loops adding over time.