A Robotic Emulator for User-Driven Design of Multi-DOF Transradial Prostheses

Abstract

Highly functional upper-limb prostheses have been developed to restore dexterous end-effector motion, but increased mechanical functionality often leads to greater weight, more complex control schemes, and higher cost. In the absence of modular, reconfigurable robotic platforms, prosthesis selection is still driven by subjective preference or brand familiarity rather than systematic evaluation. Such platforms are needed to isolate and quantify the influence of design parameters, such as wrist mobility, device weight, and control strategy, on functional performance. To address this gap, we present a novel robotic transradial prosthesis emulator, Intelligent Prosthesis Emulator for Daily Living Enhancement (I-PEDLE), that will serve as a configurable testbed for evaluating upper-limb prosthetic designs. I-PEDLE features a lightweight three-degree-of-freedom (3-DOF) transradial prosthesis leveraging a cable-driven system with off-board motors to decouple motor weight from the prosthesis. We characterize the device through dynamic trajectory tracking and multi-step response tests, then demonstrate its functional relevance in two daily living tasks (Table-Pour and Shelf-Place), comparing fixed and actuated wrists. Finally, we establish feasibility for systematic evaluation through a parameter sweep across multiple wrist configurations in a complex Shelf-Pour task. Ten healthy participants using a bypass socket emulated transradial prosthesis users. The results show that increasing active wrist DOF does not necessarily reduce excessive residual joint motion. This study establishes the feasibility of using I-PEDLE as a versatile robot-based evaluation platform to investigate how specific prosthetic wrist features may influence upper-limb coordination during functional tasks.