A study on hysteresis behaviour of SMA linear actuators based on unipolar sigmoid and hyperbolic tangent functions

Abstract The paper focuses on the description of hysteresis steady-state performance curve in shape memory alloy actuators. Using as starting point the results of previous analyses it is found that the most convenient mathematical form for its modelling is the unipolar sigmoid function. An appropriate transformation of the coordinate system simplifies the model equations and reveals a similarity pattern inherent in the shapes of all hysteresis curves.