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See detailIntegrated Simulation and Reduced-Order Modeling of Controlled Flexible Multibody Systems
Bruls, Olivier ULg

Doctoral thesis (2005)

A mechatronic system is an assembly of technological components, such as a mechanism, sensors, actuators, and a control unit. Recently, a number of researchers and industrial manufacturers have ... [more ▼]

A mechatronic system is an assembly of technological components, such as a mechanism, sensors, actuators, and a control unit. Recently, a number of researchers and industrial manufacturers have highlighted the potential advantages of lightweight parallel mechanisms with respect to the accuracy, dynamic performances, construction cost, and transportability issues. The design of a mechatronic system with such a mechanism, requires a multidisciplinary approach, where the mechanical deformations have to be considered. This thesis proposes two original contributions in this framework. First, a modular and systematic method is developed for the integrated simulation of mechatronic systems, which accounts for the strongly coupled dynamics of the mechanical and non-mechanical components. The equations of motion are formulated using the nonlinear Finite Element approach for the mechanism, and the block diagram language for the control system. The time integration algorithm relies on the generalized-alpha method, known in structural dynamics. Hence, well-defined concepts from mechanics and from system dynamics are combined in a unified formulation, with guaranteed convergence and stability properties. Several applications are treated in the fields of robotics and vehicle dynamics. Usual methods in flexible multibody dynamics lead to complex nonlinear models, not really suitable for control design. Therefore, a systematic nonlinear model reduction technique is presented, which transforms an initial high-order Finite Element model into a low-order and explicit model. The order reduction is obtained using the original concept of Global Modal Parameterization: the motion of the assembled mechanism is described in terms of rigid and flexible modes, which have a global physical interpretation in the configuration space. The reduction procedure involves the component-mode technique and an approximation strategy in the configuration space. Two examples are presented: a four-bar mechanism, and a parallel kinematic machine-tool. Finally, both simulation and modeling tools are exploited for the dynamic analysis and the control design of an experimental lightweight manipulator with hydraulic actuators. A Finite Element model is first constructed and validated with experimental data. A reduced model is derived, and an active vibration controller is designed on this basis. The simulation of the closed-loop mechatronic system predicts remarkable performances. The model-based controller is also implemented on the test-bed, and the experimental results agree with the simulation results. The performances and the other advantages of the control strategy demonstrate the relevance of our developments in mechatronics. [less ▲]

Detailed reference viewed: 527 (37 ULg)
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See detailIntegrated simulation of mechanical structures and their control system
Bruls, Olivier ULg; De Boe, Pascal; Duysinx, Pierre ULg et al

in Proc. of the 2nd Int. Conf. on Advanced Computational Methods in Engineering (ACOMEN) (2002, May)

This paper concerns the modeling and the integrated numerical simulation of flexible mechanisms subject to the action of a digital control system. A general method is proposed, based on the formalism of ... [more ▼]

This paper concerns the modeling and the integrated numerical simulation of flexible mechanisms subject to the action of a digital control system. A general method is proposed, based on the formalism of flexible multibody systems (MBS) using the Finite Element Method (FEM). Nonlinear e ects in the mechanical structure or in the control system can be taken into account. The numerical simulation tool is applied to design an active control system in a hot-dip galvanizing line, which aims at reducing the vibrations of the steel strip. [less ▲]

Detailed reference viewed: 16 (2 ULg)
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Peer Reviewed
See detailAn integrated software for building design.
Andre, Philippe ULg; Nicolas, Jacques ULg

in Proceedings of the Congres Building design, technology and occupant well-being in temperate climates. (1993, February)

Detailed reference viewed: 11 (0 ULg)
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See detailAn integrated software for passive solar building design
Andre, Philippe ULg; Nicolas, Jacques ULg

in Proceedings of ISES 93 Congress (1993, August)

Detailed reference viewed: 15 (1 ULg)
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See detailAn Integrated Software for Scantling Optimization and Least Production Cost
Rigo, Philippe ULg

in Ship Technology Research = Schiffstechnik (2003)

Detailed reference viewed: 66 (4 ULg)
See detailIntegrated strategic infrastructure networks in Enrope
Marchal, Jean ULg

Report (1998)

Detailed reference viewed: 14 (0 ULg)
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See detailIntegrated structure and control design for mechatronic systems with configuration-dependent dynamics
Da Silva, Maíra Martins; Bruls, Olivier ULg; Desmet, Wim et al

in Mechatronics (2009), 44(9), 10161025

This paper considers the optimal design of mechatronic systems with configuration-dependent dynamics. An optimal mechatronic design requires that, among the structural and control parameters, an optimal ... [more ▼]

This paper considers the optimal design of mechatronic systems with configuration-dependent dynamics. An optimal mechatronic design requires that, among the structural and control parameters, an optimal choice has to be made with respect to design specifications in the different domains. Two main challenges are treated in this paper: the non-convex nature of the optimization problem and the difficulty in modeling serial machines with flexible components and their embedded controllers. The optimization problem is treated using the direct design strategy which considers simultaneously structural and control parameters as variables and adopts non-convex optimization algorithms. Linear time-invariant and gain-scheduling PID controllers are addressed. This methodology is exploited for the multi-objective optimization of a pick-and-place assembly robot with a gripper carried by a variable-length flexible beam. The resulting design tradeoffs between system accuracy and control efforts demonstrate the advantage of an integrated design approach for mechatronic systems with configuration-dependent dynamics. 2009 Elsevier Ltd. All rights reserved. [less ▲]

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Peer Reviewed
See detailAn integrated Surface micromachined capacitive lateral accelerometer with 2 uG/rt-Hz resolution
Xuesong, J.; Wang, F.; Kraft, Michael ULg et al

in Tech. Digest of Solid State Sensor and Actuator Workshop (2002, June)

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See detailIntegrated system for decision help in urban mobility Management: Towards sustainable urban area development, VISUTRANS
Danoh, Charlemagne ULg; Ndiaye, Alassane-Ballé ULg; Marchal, Jean ULg

in WIT Transactions on Ecology and the Environment (2010), 142

Urban transport problems have become more widespread and severe than ever in both industrialised and developing countries alike. Facing this situation, there is a real need in developing new strategies ... [more ▼]

Urban transport problems have become more widespread and severe than ever in both industrialised and developing countries alike. Facing this situation, there is a real need in developing new strategies and innovative tools for transportation and town-planning as well as economic activities (public or private) within the area. The current tools and systems for solving transport problems are based on using several sub-management tools related to transportation infrastructures, town-planning, road traffic, environmental effects…which are not sufficiently in interaction. These solutions lead to severe handicap for urban homogenous and mastered development. That is why the “Urban mobility” has to be rethought. The main idea in this article concerns the development a multimodal, prospective and flexible tool for sustainable development of urban area which could help the decision makers in urban transportation fields. [less ▲]

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See detailIntegrated Two-phase Drift-flux Models for Modeling Sediment Transport
Kerger, François ULg; Dewals, Benjamin ULg

in Proceedings of the Symposium on Two-phase Modelling for Sediment Dynamics in Geophysical Flows (2011, April)

Detailed reference viewed: 54 (3 ULg)
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See detailAn integrated view of technical, economic and social factors influencing sustainabiligy of sixteen local European cattle breeds
Martin-Collado, D.; Diaz, C.; Choroszy, Z. et al

in Book of Abstracts of the 60th Annual Meeting of the European Association for Animal Production (2009, August)

This study aims to identify common patterns influencing dynamics and sustainability of 16 local European cattle breeds from Belgium, Estonia, Finland, France, Holland, Ireland, Italy and Spain. A broad ... [more ▼]

This study aims to identify common patterns influencing dynamics and sustainability of 16 local European cattle breeds from Belgium, Estonia, Finland, France, Holland, Ireland, Italy and Spain. A broad range of factors related to technical (e.g. farm size, cows/ha, land ownership), economic (e.g. cattle importance on farm and family income, type of market) and social (e.g. farmers and stakeholders attitude) aspects were surveyed on a total of 401 farms. Discriminant Analysis has been used to study the implications that heterogeneity within and across countries and breeds may have in making inferences in across country or breed analyses. Thus, farms were classified according to country and breeds. Then the objective was to evaluate how all factors available allow us to distinguish such classes. The analyses provided the percentage of observations (farms) that should not be included in the pre-defined groups (country and breed) according to the variables considered. When only economic variables were considered in the analyses, 36% and 59% of farms were incorrectly assigned to their country and breed, respectively. However, considering technical variables the proportions went down to 33% and 45%. Finally, when both groups of variables were considered 20% and 35% of farms were incorrectly assigned. To what extent these mismatches may allow us to identify general patterns has to be evaluated. [less ▲]

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See detailIntegrated water management policy, the river contract in Wallonia, an experience of a participatory water management.
Rosillon, Françis ULg; Vander Borght, Paul ULg

in Coenen, Marleen; Sacile, Roberto; Meire, Patrick (Eds.) et al Integrated water management IWM-2003. Pilot study (2003)

Detailed reference viewed: 20 (2 ULg)
See detailIntegrated “omics” approaches to investigate the chemical aspects of symbiosis in termites and potential application in ligno-cellulosic use.
Bauwens, Julien ULg; Matteotti, Christel ULg; Brognaux, Alison ULg et al

Scientific conference (2010, May 05)

Cellulosic bioethanol could be one of the solutions to satisfy the increasing demand in renewable energy. The most limitative problem is the efficiency of cellulose transformation into fermentable sugars ... [more ▼]

Cellulosic bioethanol could be one of the solutions to satisfy the increasing demand in renewable energy. The most limitative problem is the efficiency of cellulose transformation into fermentable sugars. Investigations to select new glycosyl hydrolases are an interesting approach that constitutes a potential opportunity to improve the valorization of lignocellulosic materials. Three major types of glycosyl hydolases are generally produced by organism’s that are able to efficiently use cellulosic compounds: the endoglucanases, the exoglucanases/cellobiohydrolases and the β-glucosidases. In the ability to transform lignocellulosic materials by animals, symbioses are generally observed with a range of micro-organisms including bacteria, protists and/or fungi that largely (or completely) contribute to the production of the needed enzymatic complexes. In termites, such active enzymes are produced in the insect digestive tract, by the termite insect itself or by symbiotic organisms. Within lower termites gut, such as in our model Reticulitermes santonensis (Feytaud), protists and bacteria are associated and involved in a complex symbiotic system. To investigate the respective role of the insect and different groups of symbionts, multidisciplinary “omics” approaches were here developed including proteomics (ESI-LC-MS-MS, 2D-Dige gel coupled with MALDI-TOF mass spectrometry for protein identification), genomics (with a metagenomic approach based on large cDNA bank construction), metabolomics (LC-MS stragety for carbohydrate degradation product characterization). Moreover, microorganism isolation was used to investigate and characterize glycosyl hydrolases diversity and activity in R. santonensis. The integration of this broad range of “omics” techniques allowed characterizing the role of symbionts in insects in a fundamental approach and to invtigate the chemical ecology of xylophagous insects but also corresponding to an efficient way to promote the selection of efficient enzymatic activities to potentially produce biofuels based on the use of existing lignocellulosic materials. [less ▲]

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See detailDe integratie van zorgkundigen in de thuisverpleging
Moons, P.; Gosset, Christiane ULg; Beckers, Jacqueline ULg et al

Report (2009)

Detailed reference viewed: 40 (2 ULg)
See detailIntegrating axle weight restrictions in a two-dimensional vehicle routing problem with sequence based loading
Pollaris, Hanne; Braekers, Kris; Caris, An et al

Scientific conference (2014, June)

A mixed integer linear programming model for a two-dimensional capacitated vehicle routing problem (2L-CVRP) with sequence based loading and axle weight restrictions is provided. To the authors’ knowledge ... [more ▼]

A mixed integer linear programming model for a two-dimensional capacitated vehicle routing problem (2L-CVRP) with sequence based loading and axle weight restrictions is provided. To the authors’ knowledge, it is the first time that axle weight restrictions are incorporated in a VRP. Axle weight limits impose a great challenge for transportation companies. Trucks with overloaded axles represent a significant threat for traffic safety and may cause serious damage to the road surface. Transporters face high fines when violating these limits. The problem is based on a real-world problem from a Belgian logistics service provider. The demand of the customers consists of europallets. Pallets can be placed in two horizontal rows inside the vehicle. No vertical stacking is allowed. The center of gravity of the pallets inside the vehicle is calculated to determine the axle weights. Results of the model are compared to results of a 2L-CVRP with sequence based loading without axle weight restrictions. Numerical experiments demonstrate that the model performs adequately and that the integration of axle weight constraints in vehicle routing models is necessary for a feasible route planning. [less ▲]

Detailed reference viewed: 48 (1 ULg)
See detailIntegrating biological indicators in a monitoring network to improve soil quality diagnosis – a case study in Southern Belgium
Krüger, Inken ULg; Chartin, Caroline; van Wesemael, Bas et al

Conference (2016, July 21)

Detailed reference viewed: 30 (4 ULg)
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See detailIntegrating biological information in genome-wide association interaction (GWAI) studies.
Gusareva, Elena ULg; Van Steen, Kristel ULg

Speech/Talk (2012)

Genome-wide association (GWA) studies of Crohn's disease have identified numerous genes. However, a substantial portion of the heritability of this disease remains unexplained. Some gene variants, not ... [more ▼]

Genome-wide association (GWA) studies of Crohn's disease have identified numerous genes. However, a substantial portion of the heritability of this disease remains unexplained. Some gene variants, not detectable via main effects GWA study, may manifest themselves only in interaction with other variants. To search for interacting genes involved in the regulation of Crohn's disease, we performed GWA epistasis screening in a large human cohort (1851 cases/2938 controls) belonging to the Wellcome Trust Case Control Consortium (WTCCC). All subjects were genotyped with the GeneChip 500K Mapping Array Set (Affymetrix chip). SNPs that passed our quality control (359,479 SNPs) were processed in Biofilter (a software package that looks for candidate epistatic genes contributing to disease risk) giving rise to 14,185 SNPs. Subsequent MB-MDR epistasis screening, highlighted evidence for statistical epistasis for 6 SNP pairs. Four of these pairs involve interaction on between the HTR3B and USP28 genes (chromosome 11). One pair involves an interaction between the SLED1 and ACSL1 genes (chromosome 4). Another pair involves an interaction between PTPN22 (chromosome 1) and a SNP located between USPL1 and ALOX5AP (chromosome 13). Notably, when mapped to the same genomic regions, the interacting SNPs were not in linkage disequilibrium (r^2 < 0.11). All results were corrected for potential main SNP effects and were corrected for multiple testing on 7072 SNPs (i.e., 25,003,056 pairs). We investigated the consistency of these findings using different methodologies, including information-based, LD comparison-based and regression-based approaches. We also investigated the utility of using prior information from biological interaction data bases in novel epistasis discoveries, as well as the utility of biological data bases in interpreting a posterior identified statistical epistasis pairs. Our findings may provide new leads on important pathways involved in Crohn's disease. [less ▲]

Detailed reference viewed: 16 (1 ULg)