A SMA HIGH PERFORMANCE ACTUATOR FOR ROBOT HANDS

Abstract
This paper proposes a prototype of a high performance robotic actuator, based on shape memory alloys. The actuator prototype was designed for generating a torque of 75 Nmm. It consists of a wire with rectangular section which is driving a pulley system. A bias spring is used to preload the system. This design is to be used within the links of a human-sized multi-fingered robot hand. Therefore a highly miniaturised actuator had to be built. Resistive heating and oil cooling are used to obtain the necessary transformations. Due to the low electrical resistance of the SMA, a specially designed power amplifier had to be developed. A real time position controller for this device is proposed. It is taking into account the hysteresis behaviour of the SMA material. Finally, the first experimental results for this prototype are presented.