Soft Everting Prosthetic Hand and Comparison with Existing Body-Powered Terminal Devices

<p dir="ltr">Winner of the Hesburgh Library, University Library Research Award, Emerging Scholar Award for 2025. This study presents a novel soft prosthetic hand design based on an inverting-everting toroidal hydrostat, evaluated within a body-powered transmission system. The Everting hand was compared with two existing body-powered terminal devices: the 3D-printed Kwawu hand and the Hosmer hook. Through mechanical testing and a user study with six able-bodied participants, the Everting hand demonstrated significantly lower cable tension requirements (1.6 N vs. 30.0 N and 28.1 N), higher pulling force resistance (15.8 N vs. 6.9 N and 4.0 N), and improved performance in tasks involving adaptive grasping. While the Everting hand excelled at handling varied object shapes and sizes, limitations were noted in tasks demanding fine motor precision. The study highlights the potential of soft robotic structures in enhancing user comfort and adaptability in prosthetic design.</p>