SMA Actuation for Wrist Motion with Split-tube Flexures

The research addresses alternate method of actuating a pseudo wrist motion intending to replicate a human supination/pronation motion. The actuation implemented was using a Shape Memory Alloy (SMA) wire as mimicry for a muscular action located within the boundary of the human forearm. Replacing the bone and other muscular structure which act as torsional resilience is the rigid Polyvinyl Chloride (PVC) Split-Tube Flexures. The design of the actuation method was experimented and simulated under laboratory conditions. A fixed size SMA wire was used throughout the experiment. The results gave an insight working of the split-tube flexures under linear angled forces and the behavior of SMA wires under different strain conditions. The study concluded that with use of SMA linear actuation, an angular motion could be achieved. Furthermore the research concludes that split tube flexures can be used as torsional resilience as to be able to return to the initial position, thus removing complex mechanisms.