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Graduate Exam Abstract


Rodrigo Jamisola

Ph.D. Final

July 31, 2006, 10 am

C21 Engineering

Failure-Tolerant Path Planning for Redundant Manipulators


Abstract: This work addresses the issue of finding locations in a robot's workspace that are guaranteed reachable in the presence of joint failures. This guarantee is useful for manipulators performing tasks in remote or hazardous environments that preclude direct human intervention, and for tasks where a robot failure could possibly pose a significant danger. The first part of this work considers start and goal workspace locations that are guaranteed reachable in the presence of joint failures and obstacles in the workspace. The method of finding a solution is to find a set of possible obstacle-free paths that guarantees the existence of a solution. It is shown that this set makes up a simply-connected, obstacle-free surface with no internal local minimum or maximum in the manipulator's configuration space. A necessary condition and a sufficient condition are presented that state the requirements to possibly find a solution. The second part of this work considers the problem of identifying a region in the workspace where failure tolerance can be achieved. This is performed by finding a suitable set of artificial joint limits of the robot such that the failure-tolerant workspace region exists. Characterization of the self-motion manifolds that identify the boundaries of this region is presented. Once a failure-tolerant workspace region is identified, robot tasks can be specified within this region.

Adviser: Anthony Maciejewski
Co-Adviser:
Non-ECE Member: Wade Troxell, ME
Member 3: Iuliana Oprea, Math
Addional Members: Rodney Roberts

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