An Under-Actuated Mechanism for Anthropomorphic Robotic Prosthetic Hand

This paper proposes an under-actuated mechanism for a robotic prosthetic hand in which two actuators control four fingers with individual finger having one degree of freedom. Under-actuation is achieved by using a clutch mechanism along with a cam shaft from which most finger patterns used in activities of daily life could be produced. This research focuses mainly on producing three gripping patterns; index finger extension, pinch grip and power grip. DC gear motors with inbuilt encoders enable to create motion in clutch driving mechanism and clutch engaging mechanism. Proposed design enables fingers to execute flexion and extension. The thumb is activated by a DC gear motor which can generate thumb flexion and extension. Simulations and experiments have been carried out to verify the effectiveness of motion generation of the prosthetic hand.