Prosthetic Finger Design for Partial Hand Amputees: A Five-Bar Linkage Approach

Abstract

The passive prosthetic finger is designed, modeled, and functional tested with the five-bar closed-loop linkage mechanism for partial hand amputees. The prosthesis is designed with parametric CAD modeling, forward kinematic analysis, and hybrid manufacturing techniques. One single input with one actuation point gives controlled motion to a geometrically constrained mechanism without the need for motors or electronics. Materials used are biocompatible and resistant: 316L stainless steel and carbon fiber composite. Kinematic simulations proved a stable angular displacement (64.5° - 67.5°) and homogeneous velocity and acceleration profiles with loads of 0 to 100 N. The device was efficient, well-distributed with a little deformation. Functional tests like the Jebsen–Taylor and Box & Block tests proved the prosthesis's capability of performing dexterous tasks involving precision. The whole and under $200 budget cost for fabrication of the device made it worth using in low-resource places. These results support the five-bar linkage as a mechanically effective, anatomically accurate passive prosthetic solution. This is also inexpensive compared to costly myoelectric devices and promises of widespread clinical use.