3D Analysis of Normal and Pathological Gait Based on Low-Cost Wireless Accelerometers

in URSI Benelux Forum 2012 “Antennas: multiple designs, multiple applications” (2012)

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological ... [more ▼]

We describe the principle and use of a new low-cost, wireless, 3-axis accelerometer-based device that records acceleration signals and automatically analyses them to characterize normal and pathological gait. [less ▲]

Méthode de Perturbation pour la Modélisation par Éléments Finis des Systèmes Électrostatiques en Mouvement - Application aux MEMS Électrostatiques

Doctoral thesis (2009)

La modélisation par éléments finis des conducteurs en mouvement nécessite généralement des calculs successifs et le remalliage de certaines régions. Une modélisation 3D de géométries complexes par les ... [more ▼]

La modélisation par éléments finis des conducteurs en mouvement nécessite généralement des calculs successifs et le remalliage de certaines régions. Une modélisation 3D de géométries complexes par les techniques classiques nécessite dès lors de gros efforts en terme de temps de calcul. Dans cette thèse, une méthode originale basée sur une approche par sous-problèmes, appelée méthode de perturbation, a été développée. Utilisant la méthode des éléments finis, cette technique consiste à subdiviser un problème entier en sous-problèmes. La complexité du problème initial est par conséquent diminuée en ne se concentrant que sur les zones les plus pertinentes. Appliquée aux systèmes en mouvement, la méthode de perturbation permet d'exploiter les résolutions antérieures au lieu d'effectuer un nouveau calcul pour chaque position. L'analyse par la méthode de perturbation des microsystèmes électromécaniques (MEMS) électrostatiques comprenant des parties en déplacement ou en déformation est en outre considérée dans ce travail. Il est notamment question de démontrer l'implication naturelle de cette approche pour des simulations plus efficaces et plus précises des MEMS électrostatiques. [less ▲]

An iterative finite element perturbation method for computing electrostatic field distortions

in IEEE Transactions on Magnetics (2008), 44(6), 746-749

A finite element perturbation method is developed for computing electrostatic field distortions and the ensuing charges and forces on moving conductive regions subjected to fixed potentials. It is based ... [more ▼]

A finite element perturbation method is developed for computing electrostatic field distortions and the ensuing charges and forces on moving conductive regions subjected to fixed potentials. It is based on the subsequent solution of an unperturbed problem in a complete domain, where conductive regions have been extracted, and of perturbation problems in subdomains restricted to the surroundings of the added conductive regions. The solution of the unperturbed problem serves as source (with a very reduced support) for the perturbation subproblems. For every new position of the conductors, the solution of the unperturbed problem does not vary and is thus reused; only the perturbation subproblems have to be solved. Further, this approach allows for the use of independent and well-adapted meshes. An iterative procedure is required if the conductive regions are close to the sources. [less ▲]

A Perturbation Finite Element Technique for Modeling Electrostatic MEMS

Poster (2008, March 18)

A perturbation method for the 3D finite element modeling of electrostatically driven MEMS

in Sensors (2008), 8(2), 994-1003

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving ... [more ▼]

In this paper, a finite element (FE) procedure for modeling electrostatically actuated MEMS is presented. It concerns a perturbation method for computing electrostatic field distortions due to moving conductors. The computation is split in two steps. First, an unperturbed problem (in the absence of certain conductors) is solved with the conventional FE method in the complete domain. Second, a perturbation problem is solved in a reduced region with an additional conductor using the solution of the unperturbed problem as a source. When the perturbing region is close to the original source field, an iterative computation may be required. The developed procedure offers the advantage of solving sub-problems in reduced domains and consequently of benefiting from different problem-adapted meshes. This approach allows for computational efficiency by decreasing the size of the problem. [less ▲]

A Perturbation Finite Element Method for Modeling Electrostatic MEMS without Remeshing

in Proceedings of the 9th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (EuroSimE2008) (2008)

This paper deals with the coupled electrostatic- mechanical analysis of electrostatically actuated MEMS. An iterative perturbation procedure in conjunction with the finite element method is used to solve ... [more ▼]

This paper deals with the coupled electrostatic- mechanical analysis of electrostatically actuated MEMS. An iterative perturbation procedure in conjunction with the finite element method is used to solve the coupled problem without the need of remeshing the whole electric domain. The method offers the advantage of overcoming degenerated finite elements in the mesh of some electric regions where the deflection of the MEMS moving parts is critical. The actuation of such systems is achieved by applying either an electric voltage or a global charge. [less ▲]

A perturbation method for the 3D Finite Element Modeling

Poster (2007, May 11)

Finite element modelling of electrostatic MEMS including the impact of fringing field effects on forces

in Proceedings of the 7th International Conference on Thermal, Mechanical and Multiphysics Simulation and Experiments in Micro-Electronics and Micro-Systems (EuroSimE2006) (2006)

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate ... [more ▼]

The numerical models describing the behaviour of electrostatically actuated microsystems often disregard fringing fields. However, taking the fringing fields into account is crucial for an accurate computation of the electrostatic forces. In this work, the finite element method is applied for modeling electrostatic actuators. The electrostatic force distribution is obtained by locally applying the virtual work method. A micro-beam and a comb drive are considered as test cases. The impact of the fringing field effects on the accuracy of electrostatic forces is shown through 2D and 3D parametric studies. [less ▲]