Mission: Dexterous Functionality—Redesigning the Palmar Configuration Paradigm of Underactuated Prosthetic Hands

The design of prosthetic hands presents inherent complexities and contradictions that require careful resolution during the initial design phase to achieve a functional solution. This study simplifies prosthetic hand design through an in-depth analysis of the two degrees of freedom (DoF) metacarpophalangeal (MCP) joint, critical in enabling versatile grasping capabilities. Optimal palmar finger orientations were devised using performance metrics, enabling each finger to have 3 DoF while maintaining a simplified mechanical structure. The proposed palmar configuration demonstrated significantly improved grasping performance compared to conventional parallel-fingered designs, accommodating objects of diverse shapes and sizes. A preliminary 3D printed prototype was developed and tested to validate the design. The prototype successfully demonstrated its ability to grasp a wide range of objects, substantiating the efficacy of the novel palmar configuration. This innovative design reduces mechanical complexity without compromising dexterity or functionality. It represents a transformative approach to prosthetic hand development, aligning with the principal goal of enabling users to perform activities of daily living effectively. The findings of this work introduce a novel paradigm in prosthetic hand design, offering a balanced combination of efficiency, dexterity, and practical applicability, thereby advancing the state-of-the-art in prosthetic technology.