Force-Sensorless Fault Tolerant Detection and Switching Control of Tendon-Driven Mechanisms With Redundant Tendons

Tendons in tendon-driven mechanisms are relatively weak components and sometimes break. This letter proposes a detection method of tendon breakage and a switching control system for tendon-driven mechanisms with redundant tendons. The detection method immediately detects the tendon breakage from the kinematic information of the tendons. The switching control system compensates the control performance by only using the remaining tendons. We experimentally confirm that the virtual tendon stretch in the breakage case is adequately large to detect the breakage from kinematic information. Experiments also confirm that the switching controller improves the tracking performance when a tendon is broken.