Anthropomorphic hand through bond graph with H-2 and H-∞ synthesis

This paper presents design of an anthropomorphic prosthetic hand which is actuated through single transducer. To provide more accurate and detailed model for the digital simulation of prosthesis, the Bond Graph approach is used. The prosthesis has five phalanges. Because of different parameters (length, width and weight), each phalange acts as an individual module to be designed but ultimately controlled by single source. The phalanges are actuated using flexible strings which are running over the pulleys and fixed with the transducer shaft. The damping of the pulleys and gears, stiffness of the strings, and inertias of each phalange are modeled precisely to provide better performance under different circumstances. Bond graph technique proved to be the more detailed and analytical way of designing the prosthetics to make them more controllable and efficient in the applications where highly précised functionality is desired. The transducer commissioned for the actuation of the prosthetic has also been modeled using Bond graph technique so that its functionality could be analyzed more efficiently. Considering backlash of the reducer part of transducer as an uncertainty to the prosthesis dynamics, a robust controller is designed so that the position of the phalanges could be controlled precisely and the prosthetic hand could mimic the movements more efficiently.