Optimization design of tendon-driven manipulators with high fault tolerance

A tendon-driven manipulator having redundant tendons may possess additional flexibility in operation such as being capable of optimizing the performance of tendons, reducing the burden on each tendon, and allowing fault tolerance for actuation. The purpose of this paper is to develop a methodology for synthesizing tendon-driven manipulators with high actuation redundancy for fault tolerance, and also to optimize the distribution of tendon force in the system. Characteristics of tendon-driven manipulators are briefly discussed. Criteria for the tendon-driven manipulator associated with high actuation redundancy are then established. Subsequently, constraints for such systems are derived from the null space of the structure matrix. With these constraints, manipulators can remain controllable when one of the tendons fails to function. Finally, a procedure for determining the structure of the tendon-driven manipulator is developed via an optimization-based numerical method.