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Local performance optimization for a class of redundant eight-degree-of-freedom manipulatorsLocal performance optimization for joint limit avoidance and manipulability maximization (singularity avoidance) is obtained by using the Jacobian matrix pseudoinverse and by projecting the gradient of an objective function into the Jacobian null space. Real-time redundancy optimization control is achieved for an eight-joint redundant manipulator having a three-axis spherical shoulder, a single elbow joint, and a four-axis spherical wrist. Symbolic solutions are used for both full-Jacobian and wrist-partitioned pseudoinverses, partitioned null-space projection matrices, and all objective function gradients. A kinematic limitation of this class of manipulators and the limitation's effect on redundancy resolution are discussed. Results obtained with graphical simulation are presented to demonstrate the effectiveness of local redundant manipulator performance optimization. Actual hardware experiments performed to verify the simulated results are also discussed. A major result is that the partitioned solution is desirable because of low computation requirements. The partitioned solution is suboptimal compared with the full solution because translational and rotational terms are optimized separately; however, the results show that the difference is not significant. Singularity analysis reveals that no algorithmic singularities exist for the partitioned solution. The partitioned and full solutions share the same physical manipulator singular conditions. When compared with the full solution, the partitioned solution is shown to be ill-conditioned in smaller neighborhoods of the shared singularities.
Document ID
19940023270
Document Type
Technical Publication (TP)
Authors
Williams, Robert L., II (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1994
Subject Category
CYBERNETICS
Report/Patent Number
NAS 1.60:3417
L-17289
NASA-TP-3417
Funding Number(s)
PROJECT: RTOP 586-02-11
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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