Shape change/memory actuators based on shape memory materials

Major techniques currently available to implement typical shape memory materials (such as shape memory alloys and polymers) for three basic types of shape switching actuations-one-time shape memory actuation, cyclic shape memory actuation and cyclic shape change actuation-were explored in detail. Typical actuators corresponding to these three types of actuations are systematically discussed. Possible combination of different types of shape memory materials/shape change materials and/or different stimuli for actuators with novel functions, which are not easily achievable, in particular at small scale, using conventional approaches, is presented to reveal the great potential of shape memory material based actuators in engineering applications. We provide a road map to guide engineers in the process of evaluation and selection of the right type of mechanism to meet the requirement(s) of a particular application.