On Tendon-Driven Robotic Mechanisms with Redundant Tendons

In this paper, several basic issues are discussed regarding tendon redundancy and joint stiffness adjustability for a robotic mechanism driven with redundant tendons. After briefly discussing tendon- controllability, the authors define local maximum sets of tendons that are redundant simultaneously (local maximum redundant tendon sets) and obtain an irreducible description of a redundant tendon in terms of the others. The authors obtain conditions under which the joint stiffness is adjustable using the tendons' nonlinear elasticity.