A Model Reduction Algorithm for Solving Multiple Scattering Problems Using Iterative Methods

in IEEE Transactions on Magnetics (2011), 47(5), 1470-1473

Model Reduction in Biological Systems Applied to a MAP Kinase Model

Conference (2002, November 04)

A model reduction method for the control of rigid mechanisms

in Proceedings of the ECCOMAS Conference on Advances in Computational Multibody Systems (2003, July)

This paper proposes a control strategy for flexible mechanisms. Our starting-point is a classical collocated PID control of the joint actuators designed for the equivalent rigid mechanism. An additional ... [more ▼]

This paper proposes a control strategy for flexible mechanisms. Our starting-point is a classical collocated PID control of the joint actuators designed for the equivalent rigid mechanism. An additional state feedback is implemented to control the flexible modes. On the basis of a few vibration measurements, it generates an additional command for the joint actuators. This non-collocated control scheme is designed according to the H procedure in order to have robust performances and stability with respect to configuration changes. In this paper, a new reduction methodology is presented to build a linear low-order and sufficiently accurate model of the mechanism with the PID feedback, which is suitable for the design of the H controller. First, a detailed Finite Element model of the mechanism is elaborated including the initial PID compensator. This set of nonlinear differential and algebraic equations is then linearized around a chosen reference configuration and a reduction technique is developed to extract a compact set of ordinaray differential equations. The retained degrees of freedom are the joint coordinates and a few modal coordinates representing the deformation of the whole mechanism. The kinematic description is thus decomposed into two parts, a rigid body motion described by the joint coordinates and a flexible motion for which shape functions have to be selected. For this selection, a modal analysis of the controlled mechanism is performed and the first few modes are kept, as in the Craig-Bampton or McNeal-Rubin reduction techniques. For robust performance specifications, the variations of the model with respect to the configuration changes should be estimated. Thus, the reduction procedure is realized for a few values of the joint coordinates, and the reduced models are compared. As the set of shape functions changes with the configuration, the physical meaning of the modal coordinates should be reinterpreted in each model, which is one difficulty of the approach. To illustrate the method, the case of a two-link flexible manipulator is presented. Simulation of the complete nonlinear Finite-Element model with the global control scheme is performed in order to assess the final performances of the closed-loop system. [less ▲]

Model reduction techniques to speed up multibody dynamics simulations

in 4th International Conference on Advanced Computational Methods in Engineering (ACOMEN) – Book of Abstracts (2008, May)

Model sensitivities and carbon cycle – climate feedbacks: a study with an Earth System Model

Speech (2009)

A Model to Explain the Activity of Comet Levy (1990c)

in Bulletin of the American Astronomical Society (1991, June 01)

Not Available

A model updating strategy of non-linear vibrating structures

in International Journal for Numerical Methods in Engineering (2004), 60(13), 2147-2164

The objective of this paper is to present a model updating strategy of non-linear vibrating structures. Because modal analysis is no longer helpful in non-linear structural dynamics, a special attention ... [more ▼]

The objective of this paper is to present a model updating strategy of non-linear vibrating structures. Because modal analysis is no longer helpful in non-linear structural dynamics, a special attention is devoted to the features extracted from the proper orthogonal decomposition and one of its non-linear generalizations based on auto-associative neural networks. The efficiency of the proposed procedure is illustrated using simulated data from a three-dimensional portal frame. Copyright (C) 2004 John Wiley Sons, Ltd. [less ▲]

Model validation of a dynamic embedded water base surface heat emitting system for buildings.

in Building Simulation: An International Journal (2011), 4

A numerical model is developed to assess the static and dynamic operations of a new kind of floor heat emitter. Surface floor heating systems are widely used to achieve better comfort conditions in ... [more ▼]

A numerical model is developed to assess the static and dynamic operations of a new kind of floor heat emitter. Surface floor heating systems are widely used to achieve better comfort conditions in residential and tertiary building sector. Classical floor heating systems have a low thermal response while the emitting device studied in this paper is highly reactive. It allows comfort enhancement and energy savings. A finite element method based software COMSOL Multiphysics is applied to solve the heat equation. This work focuses on the thermal behaviour of the emitter itself, but does not include a building model. A test bench has been built for this application to verify the numerical model. Both computational and experimental results demonstrate the benefits of this new heating and cooling device. [less ▲]

Model-based analysis of induced endotoxic shock in pigs with and without hemofiltration,

in Prodeedings of the Engineering & Physical Sciences in Medicine and Australian Biomedical Engineering Conference (EPSM ABEC 2008 (2008)

Model-Based Assessment of Dynamic FRC (DFRC)

in Intensive Care Medicine (2009), 35(suppl. 1), 52