Modeling of shape memory alloy actuator based on hammerstein model

Shape memory alloy (SMA) is a promising smart metallic material, which has the ability to recover its shape when heated. This interesting characteristic enables SMA to serve as an alternative to replace conventional actuators. This brief introduces a novel modeling scheme for SMA actuators. The nonlinear plant is described as an Hammerstein blockoriented model. The model parameters are identified by the recursive least squares algorithm, which is usable for online modeling and real-Time control. The convergence property of the parameter estimation can be guaranteed in the presence of persistent excitation. Experimental results have shown that the modeling scheme is effective. Its comparison with a mechanism model has demonstrated the merits of an Hammerstein model