Design of a Low-Cost Underactuated Finger Mechanism for Bionic Hand Prosthetics

Abstract

The purpose of this project was to design an underactuated mechanism that can emulate the biomechanical characteristics of a human finger. Over fifty thousand people in the United States suffer the unfortunate consequences of general limb loss every year, a majority of which are hand and finger amputees. Several robotics companies have successfully designed and engineered artificial bionic hands that provide amputees with impressive functionality. The Bebionic artificial hand is currently the most advanced in the market, priced at 11,000 dollars. Clearly, affordability is a rising concern that has yet to be addressed. In this regard, this project focused on reducing the number of actuators necessary to accomplish full range-of-motion finger flexion in an effort reduce the manufacturing, material, and production costs of modern prosthetic hands. The concept of underactuation, as well as mechanical design and control comprise the body of this paper, which addresses these topics in detail. Particularly challenging was the optimization of the kinematic synthesis among multiple four-bar linkages for finger flexion. Further research into the field of electromyography may be beneficial to this design, as it would ensure hands-free operation. Ultimately, this project succeeded in the optimization of an alternative, more affordable approach to the design philosophy of current industry-standard artificial bionic hands.