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When a manipulator suuers a joint failure, its performance can be signiicantly affected. If the failed joint is locked, the resulting manipulator Jacobian is given by the original Jacobian, except that the column associated with the failed joint is removed. The rank of the resulting Jacobian then determines if the manipulator still has the ability to(More)
In this paper, the authors examine the problem of designing nominal manipulator Jacobians that are optimally fault tolerant to one or more joint failures. Optimality is defined here in terms of the worst-case relative manipulability index. While this approach is applicable to both serial and parallel mechanisms, it is especially applicable to parallel(More)
Kinematically redundant manipulators have been proposed for use in remote or hazardous environments due to their potential for tolerance to joint failures. This article deenes a local measure of failure tolerance based on the worst-case dexterity following a locked joint failure. Optimal values of this measure are identiied and related to the required(More)
In this article, the authors examine the problem of designing nominal manipulator Jacobians that are optimally fault tolerant to one or more joint failures. In this work, optimality is defined in terms of the worst case relative manipulability index. While this approach is applicable to both serial and parallel mechanisms, it is especially applicable to(More)
This work considers kinematic failure tolerance when obstacles are present in the environment. It addresses the issue of finding a collision-free path such that a redundant robot can successfully move from a start to a goal position and/or orientation in the workspace despite any single locked-joint failure at any time. An algorithm is presented that(More)
In environments that are remote and hazardous, tasks such as repairing and maintaining a robot manipulator can be extremely difficult and costly. Under such conditions, the operational reliability of a robotic system is very important and motivates the problem of designing optimally fault-tolerant manipulators. One solution to increasing the fault tolerance(More)