Design and evaluation of two different finger concepts for body-powered prosthetic hand.

The goal of this study was to find an efficient method of energy transmission for application in an anthropomorphic underactuated body-powered (BP) prosthetic hand. A pulley-cable finger and a hydraulic cylinder finger were designed and tested to compare the pulley-cable transmission principle with the hydraulic cylinder transmission principle. Both fingers had identical dimensions and a low mass. The only thing that differed between the fingers was the transmission principle. The input energy was measured for a number of tasks. The pulley-cable finger required more input energy than the hydraulic cylinder finger to perform the tasks. This was especially the case in tasks that required high pinch forces. The hydraulic cylinder transmission is therefore the more efficient transmission for application in BP prosthetic fingers.