Robotics in disability.: Development of the MANUS-HAND dextrous upper-limb prosthesis

Disability and ageing in current societies represent a number of requirements that need to be addressed by personal and collective solutions adapted to maintain care and welfare. The primal roles of science and technology are now accepted as the pillars to improve the human activities and autonomy (Assistive Technologies). In this regard, robotics is beginning to play a main role in diverse human activities and in particular in respect to mobility and manipulation. In this paper, such assistive robotic systems are analyzed in a wide sense, discussing their interaction with the user. Next, as results of a European project (MANUS-HAND), the design and development of an upper limb prosthesis with high dexterity, modularity and feedback capabilities, are presented. This work proposes complementary approaches; a control system based on the use of myoelectic signals, adapted to the remaining capabilities of the user; the movements of the artificial fingers coordinated according to four global modes of grasping, complemented by the feedback on the amputee by means of force sensors and a vibratory output, covering the 90% of the natural manipulation abilities. From a mechanical point of view, a specific structure has been developed with three active fingers in flexo-extension and pronosupination of the wrist, including for this different types of actuators (DC motors and ultrasonic) governed with a single EMG channel. All systems are controlled by a distributed a hierarchical electronic architecture. A training and evaluation platform of the user capabilities completes the system, enabling the customization of the prosthesis by adapting the parameters to the particular capabilities of the amputee. The system has been tested following an ad hoc protocol with amputees, demonstrating the feasibility of the concepts developed in the project. Copyright (C) 2008 CEA-IFAC.