Degree of Safety and a Control System for Tendon-Driven Robotic Mechanism.

摘要

A tendon-driven robotic mechanism to work with persons co-operatively in the same area is investigated. The mechanism is driven by tendons that are more than the number of degrees of freedom and have non-linear elasticity. It has the advantage of the joint compliance adjustability. This is realized by the tendon redundancy. On the other hand, it has the disadvantage of the breakage of tendons. This makes it difficult to assure the safety of persons working co-operatively with it. But the tendon redundancy also allow us to compensate this disadvantage.This paper describes a method to cope with the tendon breakage for a tendon-driven robotic mechanism. After the basic results for the mechanism are introduced briefly, the degree of safety is defined as the maximum number of tendons allowed to be broken simultaneously without losing the control. Some results are shown with respect to the degree of safety. These are useful to design a tendon-driven robotic mechanism. Next, a method to compensate for the loss of tendon forces of broken tendons with the other tendons is discussed. It allows us safety are broken down simultaneously. Finally, simulation results are given to show the effect of the method.