Artificial muscles for soft robotics and underwater applications

Mechanical actuators are defined as mechanical devices that convert an input energy into motion. Since the 1990s, advancements in the fields of robotics and automation have produced a critical need for the development of lightweight and efficient actuators capable of human-like motion. In the past few decades, extensive research activities in the fields of materials science and smart materials have led to the development of a novel type of actuator known as artificial muscles.

This work is focused on the manufacturing, modeling, and applications of two emerging types of artificial muscles called twisted and coiled artificial muscles (TCAMs) and twisted spiral artificial muscles (TSAMs) for soft robotics and underwater applications. Scalable manufacturing systems are first fabricated for the rapid fabrication of both TCAMs and TSAMs. Manufacturing is followed by the development of physics-based dynamic models that can accurately predict the time-varying electrothermal actuation of TCAMs and TSAMs. Finally, TCAMs are mechanically characterized for their application in a powered ankle-foot orthosis. Muscular hydrostats for underwater applications inspired by the arms of octopi and powered by TCAMS are also proposed in this work. A cephalopod-inspired self-morphing smart skin containing TSAMs, and 3D-printed embedded electrodes is also developed in this work. A fouling-release smart skin actuated by TSAMs is proposed as a solution for marine biofouling. Finally, TSAMs are deployed as active vortex generators for delaying stall in small unmanned aerial vehicles (UAVs) operating at low Reynolds numbers.