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See detailModel predictive control to alleviate thermal overloads
Otomega, Bogdan; Marinakis, Adamantios ULg; Glavic, Mevludin et al

in IEEE Transactions on Power Systems (2007), 22(3), 1384-1385

An approach inspired by model predictive control is proposed to determine a sequence of control actions aimed at alleviating thermal overloads. The algorithm brings the line currents below their limits in ... [more ▼]

An approach inspired by model predictive control is proposed to determine a sequence of control actions aimed at alleviating thermal overloads. The algorithm brings the line currents below their limits in the time interval left by protections while accounting for constraints on control changes at each step. Its closed-loop nature allows to compensate for model inaccuracies. [less ▲]

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See detailModel recovery anti-windup for continuous-time rate and magnitude saturated linear plants
Forni, Fulvio ULg; Galeani, Sergio; Zaccarian, Luca

in Automatica (2012), 48(8), 15021513

In this paper two approaches are given for anti-windup design for nonlinear control systems with linear plants subject to limitations both in the magnitude and the rate of variation of the control input ... [more ▼]

In this paper two approaches are given for anti-windup design for nonlinear control systems with linear plants subject to limitations both in the magnitude and the rate of variation of the control input. Both approaches are based on the so-called Model Recovery Anti-windup (MRAW) framework. The first approach is built by treating the rate+magnitude saturation as a single dynamic nonlinearity, while in the second one, the dynamic compensator dynamics is extended with extra states to treat the two saturations separately. Both approaches lead to global stability with exponentially stable plants and local stability in all other cases. For both approaches, stability and performance guarantees are proven, numerical recipes are given and the relative merits are comparatively highlighted on a simulation example. [less ▲]

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See detailModel Recovery Anti-Windup for plants with rate and magnitude saturation
Forni, Fulvio ULg; Galeani, Sergio; Zaccarian, Luca

in European Control Conference (2009) (2009)

In this paper two alternative approaches are provided to design an anti-windup compensator for control systems subject to limitations both in the magnitude and the rate of variation of the plant input ... [more ▼]

In this paper two alternative approaches are provided to design an anti-windup compensator for control systems subject to limitations both in the magnitude and the rate of variation of the plant input. For both approaches, constructive numerical recipes are given and the relative merits are highlighted. [less ▲]

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See detailA model reduction algorithm for solving multiple scattering problems at high-frequencies
Geuzaine, Christophe ULg

in Proceedings of the Frontiers in Applied and Computational Mathematics (FACM '10) conference (2010)

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See detailA Model Reduction Algorithm for Solving Multiple Scattering Problems Using Iterative Methods
Vion, Alexandre ULg; Vazquez Sabariego, Ruth ULg; Geuzaine, Christophe ULg

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

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See detailA model reduction algorithm for solving multiple scattering problems using iterative methods
Vion, Alexandre ULg; V Sabariego, Ruth ULg; Geuzaine, Christophe ULg

in Proceedings of the 14th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2010) (2010, May)

This paper presents a new method for solving scattering problems by multiple objects. A model reduction algorithm based on the Macro Basis Functions (MBFs) method is used to find an approximate solution ... [more ▼]

This paper presents a new method for solving scattering problems by multiple objects. A model reduction algorithm based on the Macro Basis Functions (MBFs) method is used to find an approximate solution within a subspace of solutions, that are the solutions of several single scattering subproblems. Different iterative methods for the generation of the MBFs are compared. The whole process relies on a finite element approach and is applied to convex obstacles scattering. [less ▲]

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See detailModel reduction for simulating the dynamic behavior of parabolic troughs and a thermocline energy storage in a micro-solar power unit
Dickes, Rémi ULg; Desideri, Adriano ULg; Lemort, Vincent ULg et al

in Proceedings of ECOS 2015 (2015, July)

Micro-scale concentrated solar power plants are characterized by strong transients and mostly operate in off-design working conditions. Both the sizing and the control of these systems are key challenges ... [more ▼]

Micro-scale concentrated solar power plants are characterized by strong transients and mostly operate in off-design working conditions. Both the sizing and the control of these systems are key challenges whose optimization requires powerful dynamic modeling tools. In this context, a system featuring a solar field of parabolic troughs, a thermocline thermal energy storage and a 5kWe organic Rankine cycle (ORC) power unit is modeled in the Modelica language. Model reduction methods applied to the solar field and the thermal storage are investigated and analyzed to improve the computational efficiency of the problem. Each model is described and integrated in the open-source ThermoCycle library. Results of simulation under identical operating conditions are compared and the benefits and limitations of model reduction are assessed. [less ▲]

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See detailModel Reduction in Biological Systems Applied to a MAP Kinase Model
Bullinger, Eric ULg; Sauter, T.; Schoeberl, B. et al

Conference (2002, November 04)

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See detailA model reduction method for the control of rigid mechanisms
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

in Multibody System Dynamics (2006), 15(3), 213-227

This paper presents a reduction method to build closed-form dynamic equations for rigid multibody systems with a minimal kinematic description. Relying on an initial parameterization with absolute ... [more ▼]

This paper presents a reduction method to build closed-form dynamic equations for rigid multibody systems with a minimal kinematic description. Relying on an initial parameterization with absolute displacements and rotations, the method is able to tackle complex topologies with closed-loops in a systematic way and its extension to flexible multibody systems will be investigated in the future. Thus, it would be of great use in the framework of model-based control of mechanisms. The method is based on an interpolation strategy. The initial model is built and reduced for a number of selected points in the configuration space. Then, a piecewise polynomial model is adjusted to match the collected data. After the presentation of the reduction procedure and of the interpolation strategy, two applications of the reduction method are considered: a four-bar mechanism and a parallel kinematic machine-tool called "Orthoglide". [less ▲]

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See detailA model reduction method for the control of rigid mechanisms
Bruls, Olivier ULg; Duysinx, Pierre ULg; Golinval, Jean-Claude ULg

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 ▲]

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See detailModel reduction of flexible mechanisms: A numerical approach
Bruls, Olivier ULg

Scientific conference (2004, May)

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See detailModel reduction techniques to speed up multibody dynamics simulations
Heirman, Gert; Bruls, Olivier ULg; Desmet, Wim et al

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

Detailed reference viewed: 36 (1 ULg)
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See detailModel refinements of transformers via a subproblem finite element method
Dular, Patrick ULg; Kuo-Peng, Patrick; Ferreira da Luz, Mauricio et al

in Proceedings of ISEF 2015 (2015, September)

A progressive modeling of transformers is performed via a subproblem finite element method. A complete problem is split into subproblems with different adapted overlapping meshes. Model refinements are ... [more ▼]

A progressive modeling of transformers is performed via a subproblem finite element method. A complete problem is split into subproblems with different adapted overlapping meshes. Model refinements are performed from ideal to real flux tubes, 1-D to 2-D to 3-D models, linear to nonlinear materials, perfect to real materials, single wire to volume conductor windings, and homogenized to fine models of cores and coils, with any coupling of these changes. The proposed unified procedure efficiently feeds each subproblem via interface conditions, which lightens mesh-to-mesh sources transfers, and quantifies the gain given by each refinement on both local fields and global quantities. [less ▲]

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See detailModel sensitivities and carbon cycle - climate feedbacks: a study with an Earth System Model
Mouchet, Anne ULg; Loutre, M. F.; Goelzer, H. et al

Poster (2009, November)

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See detailModel strategic trade control law components
Michel, Quentin ULg

Conference (2011, May 25)

Detailed reference viewed: 37 (1 ULg)
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See detailA Model to Explain the Activity of Comet Levy (1990c)
Samarasinha, N. H.; A'Hearn, M. F.; Weaver, H. A. et al

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

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See detailModel Updating Based on Frequency Response Functions Using A General Finite Element Code
Yan, Ai-Min; Golinval, Jean-Claude ULg

in European Journal of Mechanical and Environmental Engineering (2003), 48(3), 149-162

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ... [more ▼]

Model updating techniques using frequency response function (FRF) data are studied in this paper. The numerical techniques are discussed for implementation with a large commercial finite element (FE ) code. System equivalent reduction expansion process is adopted to reduce the complete FE solutions onto the experimental degrees of freedom. The rank-deficiency difficulty with this method is overcome using either of two numerical techniques: diagonal perturbation and singular value decomposition. This second technique is also used in solving the updating equation. Experimental FRF data are compared with the FE solutions, and the updated model parameters are obtained via an iteration procedure. A simplified frequency domain assurance criterion is proposed to evaluate the correlation between the FE model and the measured structure at the chosen frequencies. After verifying the efficiency of the methods with several benchmark tests, the program is applied to an aeroplane model test. Some conclusions are given and remaining problems illustrated. [less ▲]

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See detailA model updating strategy of non-linear vibrating structures
Kerschen, Gaëtan ULg; Golinval, Jean-Claude ULg

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 ▲]

Detailed reference viewed: 13 (2 ULg)