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Acceleration and torque feedback for robotic control - Experimental resultsGross motion control of robotic manipulators typically requires significant on-line computations to compensate for nonlinear dynamics due to gravity, Coriolis, centripetal, and friction nonlinearities. One controller proposed by Luo and Saridis avoids these computations by feeding back joint acceleration and torque. This study implements the controller on a Puma 600 robotic manipulator. Joint acceleration measurement is obtained by measuring linear accelerations of each joint, and deriving a computationally efficient transformation from the linear measurements to the angular accelerations. Torque feedback is obtained by using the previous torque sent to the joints. The implementation has stability problems on the Puma 600 due to the extremely high gains inherent in the feedback structure. Since these high gains excite frequency modes in the Puma 600, the algorithm is modified to decrease the gain inherent in the feedback structure. The resulting compensator is stable and insensitive to high frequency unmodeled dynamics. Moreover, a second compensator is proposed which uses acceleration and torque feedback, but still allows nonlinear terms to be fed forward. Thus, by feeding the increment in the easily calculated gravity terms forward, improved responses are obtained. Both proposed compensators are implemented, and the real time results are compared to those obtained with the computed torque algorithm.
Document ID
19910033770
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Mclnroy, John E.
(Rensselaer Polytechnic Inst. Troy, NY, United States)
Saridis, George N.
(NASA Center for Intelligent Robotic Systems for Space Exploration; Rensselaer Polytechnic Institute, Troy, NY, United States)
Date Acquired
August 15, 2013
Publication Date
December 1, 1990
Publication Information
Publication: Journal of Robotic Systems
Volume: 7
ISSN: 0741-2223
Subject Category
Cybernetics
Accession Number
91A18393
Funding Number(s)
CONTRACT_GRANT: NAGW-1333
CONTRACT_GRANT: NGT-50357
Distribution Limits
Public
Copyright
Other

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