Shape memory alloy with bi-functionality in the master system to control a slave

Abstract

Application of a shape memory alloy (SMA) with bi-functionality, acting as a force sensor and as an actuator (sensor+haptics=‘sensaptics’) is proposed for the master side of a master – slave system. A 1-DOF master is instrumented with SMA wires to servo a 2-DOF slave. Antagonistic shape memory alloy wires employed in master system performs shared sensing and actuation; the operator's command to control the slave system is sensed by the variation in the differential electrical resistance of SMA and it functions as a haptic device to display the interactive force fed back from the slave to the master. From the haptic information the operator can make decisions and take appropriate action/correction in co-ordination with the requirement of the slave environment. The laboratory model of SMA based master – slave system is designed, developed and evaluated for its performance. The validity of the results proves the concept of shared bi-functionality.