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

• Two measurement stands are described.
• Idea of alternative SMA actuators work is presented.
• First order reversal curves of a SMA actuator are modeled.
• Similarity of hysteresis curves is explored.

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.