Dynamics and Control of a Class of Hand Prosthesis

Abstract

ii newlineABSTRACT newlineThis work contributes to the development of prosthetic finger mechanisms newlinewhich offer scope for restoration of ability to perform daily prehensile tasks by newlineactuation of passive prosthetic fingers with the help of remaining active natural newlinefingers. In prosthetic systems, the mechanism, sensing and actuation systems, newlineand controls are some of the important areas which require modeling and newlineanalysis. Causal representation based on power transactions provides better newlineunderstanding of interactions between these subsystems. A unified approach is newlinetherefore required to deal with the dynamics of such systems. Bond graph offers newlinesuch a unified approach to the dynamics of such biomechanical systems. The newlineconcept of Word Bond Graph Objects (WBGOs) provides several advantages newlinein modeling such large systems, including: compact representation; facilitation newlineof understanding of energetic and causal interactions between component newlinesubsystems; algorithmic, quick and easy object oriented programming for newlinenumerical simulations. The approach had been applied earlier to develop models newlinefor a class of hand prosthesis. This work is an elaborate extension to a redundant newlineunder-actuated three-joint string-tube based finger prosthesis for a partially newlineimpaired hand. It systematically explains the dynamics of behaviour of the newlinemechanism, interactions at translational and revolute couplings between rigid newlinephalanges, and, string-tube based joint actuation principles involved in this class newlineof prosthesis through simulations of the bond graph models. newlineIn this work a complete bond graph model has been developed for a stringtube newlinebased Three-Joint Finger Mechanism and its controller. WBGOs for newlinecomponent subsystems have been developed and then assembled to integrate newlinethe final model for trajectory and force control schemes. WBGOs have been newlinedeveloped systematically for rigid links or phalanges, translational and newlinerotational couplings at joints, string-tube mechanism, actuator controller and newlineactuation mechanism. The bond graph model also includes string-tub