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Problems in using shape memory alloys (SMA) in industrial applications are often caused by the fragmentary knowledge of the complex activation behavior. To solve this problem, Fraunhofer IWU developed a Matlab®-based simulation tool to emulate the properties of a SMA wire based on the energy balance. The contained terms result of the characteristic material behavior combined with thermal, electrical, and mechanical conditions. Model validation is performed by laboratory tests. It is shown that there is almost no difference between the measured and the simulated actuator movement. Due to the good quality of the model it is possible to use it in a control loop. Knowing current and voltage enables the computation of the electrical resistance of the actuator and can therefore be used for feedback control. Implementation of the results into industrial applications is exemplified by integration of an actuator in a flap as used in air condition systems of cars. Furthermore, the SMA-based drive will be compared to an electromechanical drive

Shape-memory-alloys (SMAs) are easy to integrate into mechanical structures and capable of handling high specific workloads. Therefore, SMAs possess an outstanding potential to serve as positioning devices in various applications. We present here the multi-domain modelling of an electrically heated SMA wire which includes changes of electrical parameters in conjunction to mechanical parameters. Due to the correlation between electrical resistance and mechanical stroke, it was possible to implement a resistance-based position control without the necessity of an external positioning sensor. In order to design a linear position controller by common rules, the highly complex and non-linear model was simplified. Controller development yielded a PID algorithm that was implemented on a rapid prototyping system as part of an SMA wire test bench. The models accuracy was verified by various measurements with different wires and multiple loads. Based on that, it was possible to design an actuator which utilises a flexible socket instead of fixed mountings

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