RIM Hand : A Robotic Hand with an Accurate Carpometacarpal Joint and Nitinol-Supported Skeletal Structure

TL;DR

The RIM Hand is a biomimetic robotic hand with an accurate CMC joint and Nitinol-supported skeletal structure, offering enhanced dexterity, compliance, and stability for prosthetic and service-robot applications.

Contribution

It introduces a flexible, biomimetic robotic hand with a realistic CMC joint and Nitinol-based skeletal support, improving dexterity and contact stability over rigid designs.

Findings

Palm deformation up to 28% matching human flexibility

Over twice the payload capacity of rigid palms

Three times contact area compared to rigid designs

Abstract

This paper presents the flexible RIM Hand, a biomimetic robotic hand that precisely replicates the carpometacarpal (CMC) joints and employs superelastic Nitinol wires throughout its skeletal framework. By modeling the full carpal-to-metacarpal anatomy, the design enables realistic palm deformation through tendon-driven fingers while enhancing joint restoration and supports skeletal structure with Nitinol-based dorsal extensors. A flexible silicone skin further increases contact friction and contact area, enabling stable grasps for diverse objects. Experiments show that the palm can deform up to 28%, matching human hand flexibility, while achieving more than twice the payload capacity and three times the contact area compared to a rigid palm design. The RIM Hand thus offers improved dexterity, compliance, and anthropomorphism, making it promising for prosthetic and service-robot applications.