Session: MR-07-04: Novel Mechanisms, Robots, & Applications

Paper Number: 194383

194383 - A Passive Bias Linkage for Kinematic Inversion of Body-Powered Prosthetic Cable Actuation 

Body-powered prosthetic terminal devices offer direct haptic feedback but are limited by fixed voluntary-open or voluntary-close configurations, constraining grasp versatility and user comfort. This work presents a passive inline cable adapter that enables kinematic inversion of body-powered prosthetic actuation that can be readily integrated into to any cable-driven device and those that could be adapted with one. By inverting the cable's actuation sense, our device provides the operating mode that the user's existing prehensor lacks by default—granting voluntary-close capability to voluntary‑open prehensors and voluntary‑open capability to voluntary‑close prehensors—without any modification to the terminal device. The mechanism sits inline with the existing input cable and uses a bias linkage that establishes a new mechanical equilibrium, through which the original cable tension acts in the opposite actuation sense. To ensure reliable behavior across users and device geometries, the adapter’s linkage parameters and cable path were further refined to minimize frictional losses and maintain smooth transitions between states. Cable routing geometry is optimized numerically to achieve the required differential in cable payout between configurations. Force-displacement characteristics evaluated through simulation confirm actuation inversion in both conversion directions across the clinically reported operational cable tension range, with proportional control and continuous cable tension preserved throughout.

Presenting Author: Albet Gan University of Connecticut

Presenting Author Biography: Albert Gan an Electrical and Computer Engineering undergraduate at University of Connecticut.