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Large-Scale Numerical Simulations of Human MotionThis paper examines the feasibility of using massively-parallel and vector-processing supercomputers to solve large-scale optimal control problems for human movement. Specifically, we compare the computational expense of determining the optimal controls for the single support phase of walking using a conventional serial machine (a Silicon Graphics Personal Iris 4D25 workstation), a MIMD parallel machine (an Intel iPSC/860 comprising 128 processors), and a parallel-vector-processing machine (a Cray Y-MP 8/864). With the human body modeled as a 14 degree-of-freedom linkage actuated by 46 musculotendinous units, computation of the optimal controls for walking could take up to 3 months of CPU time on the Iris. Both the Cray Y-MP and the Intel iPSC/860 are able to reduce this time to practical levels. The optimal control solution for walking can be found with about 77 hours of CPU time on the Cray, and with about 88 hours of CPU time on the Intel. Although the overall speeds of the Cray and the Intel were found to be similar, the unique capabilities of each machine are best suited to different parts of the optimal control algorithm used. The Intel performed best in the calculation of the derivatives of the performance criterion and the constraints. In contrast, the Cray performed best during parameter optimization of the controls. These results suggest that the ideal computer architecture for solving very large-scale optimal control problems is a hybrid system in which a vector-processing machine is integrated into the communication network of a MIMD parallel machine.
Document ID
19960021769
Document Type
Conference Paper
Authors
Anderson, Frank C.
(Texas Univ. Austin, TX United States)
Ziegler, James M.
(Texas Univ. Austin, TX United States)
Pandy, Marcus G.
(Texas Univ. Austin, TX United States)
Whalen, Robert T.
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
August 17, 2013
Publication Date
May 1, 1994
Publication Information
Publication: Dual-Use Space Technology Transfer Conference and Exhibition
Volume: 1
Subject Category
Man/System Technology And Life Support
Accession Number
96N25044
Funding Number(s)
CONTRACT_GRANT: NAG5-2217
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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