The Yale MyoAdapt Hand: A Highly Functional and Adaptive Single Actuator Prosthesis

The drawbacks of many commercially available multi-actuator prosthetic hands have led to high rejection rates in both adults and children. For an active lifestyle, there is a need for a device that is both lightweight and easy to control. Underactuation has quickly become an attractive solution in prosthetics by reducing the control burden and the weight of multi-actuator hands while still providing a compliant anthropomorphic grasp. In this paper we present the design and evaluation of a novel single actuator prosthetic hand. The hand uses adaptive mechanisms to allow for three unique grasp types with varying grasp rates, force output and thumb positions. The hand kinematics and geometry are optimized to prevent against common grasp failure modes of underactuated grippers. The hand was evaluated through benchtop and human subject testing to evaluate its effectiveness on activities of daily living. Additionally, we compared the performance of the hand to previously published results from a powered hook, a single actuator anthropomorphic robotic hand, and several commercial multi-actuator anthropomorphic robotic hands. The results show that the hand is comparable even to multiactuator commercial devices with users who have trained on these devices for several months to years.