Micro-Robotic Medical Tools Employing SMA Actuators for Use in the Human Body

Several micro-robotic medical tools, including catheters, guide wires, and endoscopes, employing shape memory alloy (SMA) actuators have been proposed and developed for use in the human body. This paper describes the basic principle of SMAs and the characteristics of several mechanisms, such as unidirectional bending, multi-directional bending, torsional movement, extension, and stiffness control. Moreover, some medical applications, such as insertion assistance and endoscopic and laser positioning, are described.