KINEMATIC AND STRUCTURAL DESIGN ASSESSMENT OF FAULT-TOLERANT MANIPULATORS

Fault tolerance technology promises higher system reliability even und er unexpected component failure. Such capability is attained by develo ping a structural system design that can deliver fault tolerance, and by designing controllers that can take advantage of the fault-tolerant structure. This paper reviews fault-tolerant design issues from a kin ematic and structural viewpoint. This is accomplished by studying the kinematic design of a fault-tolerant robotic system at four levels: (1 ) Joint level (Single and dual actuators); (2) Link level (Serial and parallel modules); (3) Sub-system level (Non-redundant and redundant m anipulators); (4) System level (Multiple cooperating manipulators). Th is work addresses the four levels from a structural design viewpoint A measure is developed to determine the relative fault-tolerant capacit y gained from one manipulator to another. Other criteria are also revi ewed in evaluating various manipulators as design alternatives in an e ffort to identify the most efficient structural modifications to enhan ce fault tolerance of a robot.