Design and Characterization of Soft Hyperboloidal Actuator
Soft robotic actuators are usually driven by pneumatic or hydraulic pressure, which requires pumps, valves, tubing, and seals. This supporting hardware adds bulk, latency, and additional failure modes. Twisted-string actuation (TSA) removes the need for it, but existing designs treat the twisted element as an isolated linear transmission acting against rigid boundaries. This thesis presents the Hyperboloidal Soft Actuator (HSA), in which twist and structural deformation are coupled by design. Eight compliant thermoplastic polyurethane (TPU) struts span two rigid circular end plates. Relative rotation of the plates draws the struts into a hyperboloidal ruled surface, and the actuator contracts along its axis. We derive a rigid-link kinematic model that predicts the ideal contraction path, and we use the deviation between the measured and predicted paths as a direct measure of structural compliance. We further test the actuator under axial load to determine how this compliance affects contraction and force output.
Advisor: Professor Cagdas Onal
Committee: Professor Connor McCann, Professor Pratap Rao
Zoom link: https://wpi.zoom.us/j/97270119497