Design and control of an underactuated cybernetic artificial hand

The human hand is not only an ideal effective tool but also an ideal instrument to acquire information from the external environment and it is connected with an ideal processing unit, the central nervous system (CNS). The cybernetic prosthetic hand aims to be directly interfaced to the CNS in order to improve the performance of the prosthesis in terms of acceptability, functionality, and controllability. In fact a cybernetic prosthetic hand has to replicate as much as possible the sensory-motor capabilities of the natural hand in terms of sensing and control, and it must be felt by an amputee as the lost natural limb delivering her/him a natural sensory feedback by means of the stimulation of some specific afferent nerves. Moreover, it will be controlled in a very natural way by processing the efferent neural signals coming from the central nervous system. The authors have already developed some artificial hands for robotic and prosthetic applications and their control system. In this paper some research efforts towards the realization of a cybernetic hand prosthesis are presented with specific focus on the biomechatronic design and the preliminary electromyography-based control system. In particular, the analysis of the natural low level control mechanisms and of the cognitive feedback information has been used for designing the CYBERHAND prosthetic hand. An experimental setup of the CYBERHAND system including an electromyography-based control system, a preliminary low level control system and the first biomechatronic hand has been integrated and presented in this paper.