Forward dynamical analysis of flexible multibody systems using system-level model reduction

Fast simulation (e.g., real-time) of flexible multibody systems is typically restricted by the presence of both differential and algebraic equations in the model equations, and the number of degrees of freedom required to accurately model flexibility. Model reduction techniques can alleviate the pro...

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Bibliographic Details
Published in:Multibody system dynamics Vol. 25; no. 1; pp. 97 - 113
Main Authors: Heirman, Gert H. K., Naets, Frank, Desmet, Wim
Format: Journal Article
Language:English
Published: Dordrecht Springer Netherlands 01.01.2011
Subjects:
Automotive Engineering
Control
Dynamical Systems
Electrical Engineering
Engineering
Mechanical Engineering
Optimization
Vibration
Flexible multibody dynamics
System-level model reduction
Real-time simulation
Global modal parameterization
Configuration-dependent modal description
ISSN:1384-5640, 1573-272X
Online Access:Get full text
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Summary:Fast simulation (e.g., real-time) of flexible multibody systems is typically restricted by the presence of both differential and algebraic equations in the model equations, and the number of degrees of freedom required to accurately model flexibility. Model reduction techniques can alleviate the problem, although the classically used body-level model reduction and general-purpose system-level techniques do not eliminate the algebraic equations and do not necessarily result in optimal dimension reduction. In this research, Global Modal Parametrization, a model reduction technique for flexible multibody systems is further developed to speed up simulation of flexible multibody systems. The reduction of the model is achieved by projection on a curvilinear subspace instead of the classically used fixed vector space, requiring significantly less degrees of freedom to represent the system dynamics with the same level of accuracy. The numerical experiment in this paper illustrates previously unexposed sources of approximation error: (1) the rigid body motion is computed in a forward dynamical analysis resulting in a small divergence of the rigid body motion, and (2) the errors resulting from the transformation from the modal degrees of freedom of the reduced model back to the original degrees of freedom. The effect of the configuration space discretization coarseness on the different approximation error sources is investigated. The trade-offs to be defined by the user to control these approximation errors are explained.
ISSN:1384-5640
1573-272X
DOI:10.1007/s11044-010-9214-y