Beyond Humanoid Prosthetic Hands: Modular Terminal Devices That Improve User Performance

TL;DR

This paper presents modular, non-humanoid prosthetic devices that outperform traditional humanoid designs in task performance, user effort, and adaptability, challenging the conventional anthropomorphic approach in prosthetics.

Contribution

It introduces four open-source modular non-humanoid prosthetic devices tailored for specific tasks, demonstrating significant improvements over humanoid prostheses.

Findings

Non-humanoid prostheses improve task performance

Reduced user compensatory movements

Lower task load for users

Abstract

Despite decades of research and development, myoelectric prosthetic hands lack functionality and are often rejected by users. This lack in functionality can be partially attributed to the widely accepted anthropomorphic design ideology in the field; attempting to replicate human hand form and function despite severe limitations in control and sensing technology. Instead, prosthetic hands can be tailored to perform specific tasks without increasing complexity by shedding the constraints of anthropomorphism. In this paper, we develop and evaluate four open-source modular non-humanoid devices to perform the motion required to replicate human flicking motion and to twist a screwdriver, and the functionality required to pick and place flat objects and to cut paper. Experimental results from these devices demonstrate that, versus a humanoid prosthesis, non-humanoid prosthesis design dramatically improves task performance, reduces user compensatory movement, and reduces task load. Case studies with two end users demonstrate the translational benefits of this research. We found that special attention should be paid to monitoring end-user task load to ensure positive rehabilitation outcomes.