The Design of a One-Degree-of-Freedom Master-Slave Device Based on a Shape Memory Alloy Actuator

A one-degree-of-freedom master-slave device was built using shape memory alloy (SMA) wires for actuation. A bang-bang control scheme was used for both the position control of the slave and the force control of the master. A prototype was built to demonstrate stability and other aspects of the design concept. Air cooling of the SMA wires proved inadequate, causing the slave to lag behind the master when the slave wires were being returned to extended length. An experiment was performed to determine the cooling time constants for the SMA wire in air, water, and a 50/50 mixture of water and glycerol.