Development of prosthetic hand – A preliminary study

Abstract

The purpose of the study is to develop a prosthetic hand that able to perform the four essential tasks: cylindrical grasp, key pinch, pulp to pulp pinch and tripod pinch. The human hand could be considered as a linkage system of the intercalated bony segments. Therefore, prosthetic fingers and thumb were often modeled as a planar three-link open chain each, whose plane of motion was defined by yaw at the base joint. All the four fingers were modeled the same exclude for the lengths of each segment, and arranged parallel to one another on the xy-plane. All fingers maintain the same size due to assumptions that normal hands maintain similar anatomical structure and dimensional proportion, regardless of their sizes. The hand was modeled so that it will form an equiangular motion path and reach an optimum working space to meet the objective of the study. An experiment to observe the fingertip trajectory and stability of movement for each finger was carried out using motion analysis equipment available in the Motion Analysis Laboratory, Department of Biomedical Engineering, University of Malaya.