Characterization of SMA actuator for applications in robotic neurosurgery

Shape memory alloy has been proven to be MRI compatible and due to its unique microstructure and molecular characteristics, it possesses many unique properties. Additionally, internal resistive heating of the wires eliminates the need for bulky external heating mechanisms. These advantages make SMA actuators good candidates for a wide range of applications in robotic surgical systems when compared to conventional actuators. In this paper, we present our preliminary work towards the development of a SMA based miniature robot for neurosurgery which can be operated under MRI. In this robot, we use two antagonistic SMA wires as actuators for each joint, so that each joint can be operated separately. We also designed an experimental setup to test the SMA wires. The goal of this experiment is to develop a systematic test especially for this robot and to collect sufficient data to estimate the performance of the robot. This setup can also be used to test SMA wires themselves. The data from this experiment will be used to determine important material parameters that are required for analytical models, and then use those models to develop a control strategy to manipulate the SMA actuators.