The Control Technique Research Of Rotary SMA Actuator

Shape Memory Alloy(SMA)actuators have broad application prospects in many fields, but due to the nonlinearity of inherent hysteresis of SMA, the precise position control system was very difficult to be obtained to this kinds of actuators, and it has become the biggest obstacle for the widely application of SMA actuators in the fields of smart structures. Therefore, the reaearch on the control technology of SMA actuators has important theory meaning and practical value to extend the application of SMA actuators.A thermomechanical hysteresis model of bias-type and differential type SMA actuators based on the one-dimension constitutive laws developed by Tanaka-Liang et al is presented. The open loop response characteristecs validate the validity of the model.Whereas the nonlinearity of inherent hysteresis of SMA, the fuzzy PID control strategy is presented. The fuzzy self-adaptive controller and fuzzy-PID composite controller are designed to control theSMA actuators system.The movement characteristic and the control effects with different controllers of bias type and differential type SMA actuators are simulated, the advantages and disvantages of the controllers are analyzed, the results of simulation and analysis provide theoretical basis for the best control of SMA actuator systems.