Development of a shape memory alloy actuator for transanal endoscopic microsurgery

This paper describes problems in traditional transanal endoscopic microsurgery (TEM), and proposes a mechatronics approach in new design. As one of several actuation mechanisms to expose rectal cavity, a compression coil spring made of shape memory alloy (SMA) has been studied. A custom SMA spring actuator was designed to displace 12 mm with 45 N driving force. This actuator was embedded with our new TEM tubular structure and can be used to expose a rectal site up to 60 rum wide and 80 mm long. This exposure is considered to be sufficient for treating many tumors.