Architecture design of a multiaxis cellular actuator array using segmented binary control of shape memory alloy

Abstract

A new approach to artificial muscle actuator design is presented, and is implemented using shape memory alloys (SMA). An array of SMA actuators is segmented into many independently controlled, spatially discrete volumes, each contributing a small displacement to create a large motion. The segmented cellular architecture of SMA wires is extended to a multiaxis actuator array by arranging the segments in a two-dimensional (2-D) array. The multiaxis control is streamlined and coordinated using a 2-D segmentation method in order to activate multiple links of a robot mechanism in a coordinated manner. The basic principle of segmented binary control (SBC) is first presented, followed by multiaxis segmentation theory and a design procedure. The method is applied to a five-fingered robotic hand capable of taking a variety of postures. A 10-axis SMA actuator array is built, and SBC is implemented using Peltier-effect thermoelectric devices for selective local heating and cooling. Experiments demonstrate the feasibility and effectiveness of the new method.