Three different artificial hands have been designed in the framework of collaboration between the INAIL/RTR Centre and the Arts of Lab of Scuola Superiore Sant'Anna (SSSA) with the aim of developing a novel generation of prosthetic hands with increasing performance in restoring grasping functionalities in case of hand amputation. After having illustrated the philosophy and the methods of the biomechatronic approach to the design of prosthetic devices, the three different artificial hand prototypes are presented and described. A novel experimental protocol to assess hand performance has been conceived in order to provide quantitative parameters to analyze and compare various hands. The most important physical quantities to be rigorously measured and compared are the forces exerted on the object in different locations on the hand and in different grasping conditions. In particular, the test protocol is composed of six different experimental tests intended to measure the grasping force during the precision grip, the power grasp and the lateral pinch. The results obtained by applying the test protocol to the three prototypes are presented and discussed. In conclusion the paper presents the specifications of a novel prosthetic hand coming out from analysis presented in this paper.