Tendon drive finger mechanisms for an EMG prosthetic hand with two motors

EMG prosthetic hands are being extensively studied to meet with the need of the millions of physical disabilities who have lost a hand or both hands. But for most of existing multi-degree of freedom EMG prosthetic hands, shortcomings such as low intensity, high price, et al., have blocked them from practical realization. Low-degree freedom EMG prosthetic hand with high performance is therefore desired to solve these problems. The aim of this study is to optimize the low-freedom degree EMG prosthetic hand based on utilization rate of human hand´s joints in daily life. We used two motors to realize the rotary motions of CM joints and three kinds of tendon drive mechanism of MP joints. The low-freedom degree EMG prosthetic hand can also complete powerful grasp, precise grasp and lateral grasp which account for 85% hand motions in daily life. Stress analysis is also performed to guarantee safety in daily use. Finally, a pick-and-place experiment was conducted to evaluate the designs.