Design and experimental validation of a hybrid actuator based on piezoceramics and shape-memory-alloys

In this paper we present the design and experimental validation of a novel hybrid actuator combining the advantages of shape memory alloys and piezoceramics in one setup. The SMA-part of the Actuator enables the required stroke superimposed by the piezo-part which ensures precision and the aimed dynamics. The two actuator parts are developed regarding geometry, applied load and control aspects. Beyond that control concepts for positioning applications are investigated. At the beginning the actuator parts piezo and SMA are considered as single and independent control loops to develop the base of the actuator control. Further, these control loops are interconnected to realize an overlaid actuator control. There are two concepts to be considered. Firstly, an open loop concept based on dynamic splitting using signal filters and secondly a concept basing on a cascaded arrangement to exploit the whole potential of this combination. Furthermore a hybrid actuator is built to investigate its properties. Experimental results further show its potential to serve as miniaturized positioning device for small machines.