Title: Synthesis of kth order fault-tolerant kinematically redundant manipulator designs using relative kinematic isotropy

Authors: Frank L. Hammond III

Addresses: Harvard School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA

Abstract: Fault tolerance has become an essential capability in manipulator design methodologies as robotic manipulation systems are more frequently employed in hazardous environments and on geometrically complex or heavy duty industrial operations, where mechanical joint failures are likely to occur. This work focuses on the development of a redundant manipulator design methodology aimed at minimising the degradation in manipulator performance quality that results from k arbitrary joint failures. The relative weighted global isotropy index (RWGII) is developed for use as a manipulator design fitness metric. This metric takes into account the primary manipulation goal of maintaining kinematic dexterity, the secondary goals of collision avoidance and torque minimisation, and fault tolerance capability. The genetic algorithm search of an immense manipulator design space, conducted using the new fault-tolerant manipulator design fitness metric, yields redundant manipulator designs that effectively minimise fault susceptibility due to k joint failures while maintaining dexterous, redundancy-resolved motion on specific tasks.

Keywords: kinematic redundancy; robot dynamics; robot kinematics; optimisation; weighted isotropy; manipulability; constrained optimisation; fault tolerance; manipulator design; robot design; kinematic isotropy; redundant manipulators; redundant robots; collision avoidance; torque minimisation; genetic algorithms.

DOI: 10.1504/IJAIS.2014.060994

International Journal of Adaptive and Innovative Systems, 2014 Vol.2 No.1, pp.73 - 96

Received: 29 Feb 2012
Accepted: 19 Aug 2012

Published online: 28 Jun 2014 *

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