Development of a prosthetic hand for power grasping applications

Abstract

The human hand is an is an exceptionally significant part of the human body with a very complex biological system having bones, joints, and muscles, to provide many degrees of freedom. Among all the grasp patterns of hand, power grasping plays a crucial role in daily activities of a human. During the past few years, there was a rapid development in prosthetic limb technology to be used for the upper limb amputees. In this research, a prosthetic terminal device has been developed to assist the power grasping activities of daily living ofupper limb amputees. The designed terminal device includes four fingers, which generates eight degrees of freedom. In order to generate finger movements, a novel linkage mechanism has been proposed. Notably, the proposed mechanism can be characterized as a combination ofparallel and series links. The mobility of the system has been analyzed according to ChebychevGriibler-Kutzbach criterion for a planar mechanism. By considering the easy fabrication, the linkage finger mechanism was redesigned based on the design for manufacturing guidelines. With the intention of verifying the effectiveness of the mechanism, kinematics analysis has been carried out by means ofthe geometric representation and Denavit-Hartenberg parameter approaches. Subsequently, a Matlab program has been developed, in order to proceed with the numerical study. Furthermore, the motion simulation and static structural analysis proved that the mechanism is capable of generating the required finger movements for power grasping. Furthermore, trajectories and the configuration space of the proposed finger mechanism has been determined by using the motion simulations inbuilt with Solidworks software package. The movements of the finger mechanism, which is fabricated by 3D printing was experimentally tested. Experimental results proved the effectiveness of the proposed mechanism to accomplish the expected motion generation. In addition, the finite e