Mesoscale Shape Memory Alloy Actuator for Visual Clarity of Surgical Cameras in Minimally Invasive Robotic Surgery

This paper proposes a mesoscale shape memory alloy (SMA) actuator for cleaning the contaminated lenses of surgical cameras during minimally invasive robotic surgery. The proposed design features minimal intraopertive interruption to maintain visual clarity of fully insertable surgical cameras by quickly removing vapor condensation, particle debris, body fluids, etc. that adhere to the cover lenses. Inspired by the mechanical properties of 1-D SMA materials, a set of SMA wires are employed to drive an eyelid wiper that is concealed in the module's edge. By analyzing the actuation mechanism, we provide a design guideline for developing a functional modular actuator. A numerical computation model is also proposed to predict the actuation cycles according to various combinations of design parameters. The performance of an initial prototype is experimentally evaluated by introducing three different contamination sources, i.e., fogging, bone dusts, and blood. The predicted actuation cycle is experimentally validated with 95.2% prediction accuracy. And the actuation cycle of the eyelid wiper is about 2 s.