A Lightweight Transradial Prosthetic Emulator for Optimizing Prosthetic Wrist Design

Researchers have developed devices with increased active joints, targeting similar dexterity to the physiological arm. However, studies have shown that the user task per-formance or dexterity did not necessarily improve with the increased functional dexterity of the prosthetic arm. This presumably stems from the heavier weight that is incased for higher active DoF or control difficulty to modulate high DoF prosthetic system. There are limited quantitative methods or tools to decouple various prosthetic parameters to understand the effect of these parameters on the upper limb performance. For example, active DoF and weight are coupled because higher function leads to additional motors, batteries, and other electronics which make the device heavier. Robotic emulators have been used for lower limb studies to decouple the device weight and high functionality in order to explore human-centered designs and controllers featuring off-board motors. In this study, we designed a prosthetic emulator for transradial (below elbow) prosthesis to change only specific parameters of interest to understand individual design or control parameters. The emulator arm only weighs half of the physiological arm which features two active wrist movements with active power grasping. We envision this emulator can serve as a testbed to identify the desired specification of transradial prosthesis, human-robot interaction, and human-in-the-loop control.