Model of a NiTi shape memory alloy actuator

A model of motion of an agonistic–antagonistic shape memory alloy actuator is developed in this article. The model shows that the dynamics of the actuator can be well described by a nonlinear motion model of human muscle with nonlinear damping. To complete the model, a method for the determination of the damping properties of the actuator system is suggested. To this end, an analytical expression for the damping coefficient of the system was developed. The experimental verification of the proposed model of motion was conducted through a comparison of the experimentally measured and numerically simulated step responses. The simulated step responses were in close agreement with their experimentally measured counterparts on the shape memory alloy actuator prototype.