Research on novel compact actuators based on shape memory alloy springs

This paper describes the development of a new structure of compact flexible actuator based on SMA springs. The SMA actuator which allows a large bending angle and spatial bending for practical application and has a simple structure for miniaturization. An SMA actuator 6 mm in outer diameter with three shape memory alloy springs was designed and fabricated. The practical specifications of the SMA coil spring were determined based on a design chart and equation. The mechanical properties of the bending part were investigated. After analyzing equilibrium of elastic rod with distributed and concentrated loads, the parameters design process of the rod and SMA spring are deduced. Subsequently, the manufacture of the prototype is discussed in details and the drive and control system is implemented also. Finally, the experiments of the actuator proof fine qualities of the operation performances.