Design, Construction and Testing of a Prototype of Transradial Hand Prosthesis with Two Degrees of Freedom Cable-Controlled and Voice-Activated

Abstract

This study focuses on the design, construction, and testing of a transradial hand prosthesis with two degrees of freedom, controlled by cables and activated by voice, aimed at improving the daily task performance of individuals with motor disabilities. A descriptive study with a quantitative approach was conducted, utilizing anthropometric measurements of hands taken from students at the Escuela Superior Politécnica de Chimborazo. The resulting prototype features a cable-actuated mechanism, with individual mechanical fingers, and is made from polylactic acid (PLA). The primary function of the prosthesis is the opening and closing motion of the fingers. Through direct and inverse kinematic analysis, the position of each finger was determined, and their respective velocities and accelerations were calculated. The maximum speed achieved by the thumb was 0.057 mm/s, while the other fingers reached a speed of 0.62 mm/s. The thumb's acceleration was 1.179 mm/s², while the other fingers had an acceleration of 0.35 mm/s². In practical tests with various objects, the prosthesis was able to lift a maximum weight of 220 grams, with the ideal weight for optimal performance ranging between 100 and 120 grams.