PHYSICAL ACTIVITY IN VIRTUAL REALITY

The purpose of this conference is to discuss about research on human physical activity based on Virtual Reality (VR). VR 1) offers a unique compromise between control and ecological property of the studied situation, 2) enables to enrich/modify the physical environment, 3) provides control on the multisensory feedback given to the user, 4) and has the potential to enhance motivation and increase the number of repetition in motor skills training. Recent democratisation of immersive technologies, with the development of cheap interactive devices for videogames, has encouraged research in this domain. In this conference, we will address examples of perception-action coupling analysis based on VR, will analyse how technical choices could affect the behaviour of the studied subjects, and will expose perspectives in motor skills training based on VR

Design Optimization Methodology for Power Converters based on Global Energy Requirement Criteria. Application to a Flyback DC-DC Structure

International audienceThis paper discusses a design methodology for power electronic converters according to the Global Energy Requirement (GER) criterion, i.e. the primary energy consumption over their entire life cycle. For given specifications of the converter, each power component of a self-oscillating flyback converter and the main control parameters are optimized using scaling laws for given technologies. Models linking sizes of components, loss parameters and embodied energy parameters are presented. Finally a comparison is realized between a GER-designed converters and a classical one (designed from thermal criteria) which concludes to an improvement of efficiency for a given consumption profile

Une approche de dimensionnement sur cycle de vie pour l'analyse du potentiel de la distribution en courant continu dans le bâtiment

National audienceLe nouveau contexte énergétique au sein du bâtiment (apparition des systèmes PV en toiture et des véhicules électriques) pose à nouveau la question de la distribution en continu au sein des bâtiments. Dans un contexte où l'énergie et les impacts environnementaux prennent chaque jour plus d'importance, la quantification des performances d'un tel système selon sa seule phase d'usage (pertes énergétiques) ne répond pas complètement à la question de l'impact global des usages. Dans cette optique nous proposons d'éco-dimensionner les composants constituant ce système sur la base d'une minimisation de l'énergie primaire qu'ils consomment pendant tout le cycle de vie (pertes + énergie grise), l'un des objectifs étant d'évaluer le niveau de tension optimale pour ce réseau de distribution en courant continu. Cet article présente les modèles élaborés pour les éléments de puissance pour déterminer les pertes et l'énergie grise, ensuite des résultats d'optimisation sont présentés. The new energetic context inside building (emergence of photovoltaic array and electric vehicle) should incite us to reconsider the use of DC distribution scheme for building. Since the environmental and energetic impacts become more and more important, the efficiency assessment of such system is nowadays not sufficient to quantify its global environmental impacts. In this context, we propose to eco-design the components of such system minimizing their primary energy consumption during their whole life cycle (from raw material extraction to recycling process). The global aim of our work is to determine the best voltage level for such system according this criterion. This article presents the models which have been developed to assess the primary energy consumption of power electronic components and some eco-designs and sensitivity studies are presented

Wiring design based on Global Energy Requirement criteria: a first step towards an eco-designed DC distribution voltage

International audienceNowadays, the global energy context leads to a need for the development of distributed Renewable Energy Sources (RES). Since most of them produce direct current while electricity flows in alternative current in the network, the energy produced by RES has to be converted. As modern electrical loads and storage systems can be potentially fed with direct current, the DC distribution scheme need to be evaluated. Then, we need to determine its specification (topology, voltage level, protection device...). Some papers have already shown the reduction of conduction losses induced by a DC distribution [1], others presented some distribution schemes [2] or efficiency analysis [3]-[4] for different voltage levels in a given case study. This paper proposes the first steps of a method for the optimization of the voltage level for a DC distribution scheme according to environmental issues, and focuses on the wire eco sizing. In a first part, we will present our global approach, i.e. the constituent which will be taken into account and the criteria which has been selected before focusing on the wiring design. In a second time, we will present the models and the case studies which have been considered to design wires. And finally we will present our results, comparing our approach with the recommendation made by French standards in our case studies and carrying out a sensitivity study about our working hypothesis

Investigation of DC distribution by measuring and modelling power supply devices for buildings with PV production

International audienceDue to governmental incentive policies, most of the photovoltaic panels installed in France are connected to the power grid, thus requiring power transformation components. Since any type of load can be potentially fed with direct current, we investigated DC distribution by measuring and modelling power supply devices. This paper presents measurement methods, models and validation, with concrete application for a multimedia workstation. Finally, we expose the prospects of our work whose goal is to optimize the value of DC voltage to minimize energy consumption (especially global energy requirement) throughout the life cycle

VIRTUAL REALITY & SPORT

This applied session deals with the design of immersive environments for human motion performance analysis. In a first part of the session, a theoretical presentation describes the aims and scopes of such type of experiments. In a second part of the session, a review of the available immersive systems will be exposed. Finally, a practical framework will be designed in real-time with the attendees: a low-cost immersive environment based on a Microsoft Kinect, a Razer Hydra and an Oculus Rift Head Mounted Display device. We will develop an experiment to analyse perception-action coupling in soccer with simulated virtual opponents enabling to analyse the decision-making of a real goalkeeper

TRAINING FAVORS THE FORWARD PROGRESSION DURING HUMAN LOCOMOTION

The purpose of this study was to test if the mechanical locomotion technique was linked to training. To this end we calculated the different kinetic energies ratios to the total kinetic energy in three groups (untrained, sprinter and endurance-trained men) during walking and running on a treadmill. It appeared that walking was distinguished from running by higher translational body segments movements in the sagittal plane. Moreover training was necessary to favor the forward progression by minimizing interference movements at all walking and running speeds

Caractérisation d'un générateur portable : de l'énergie humaine à l'électricité

National audienceDans cet article, nous nous intéressons à la problématique de l'alimentation des appareils portables liée à la consommation d'accumulateurs et à la dépendance des recharges sur secteur. Le corps humain produit de l'énergie renouvelable, non polluante et de durée de vie élevée : entre chaleur dégagée, lumière reçue et énergie mécanique disponible, cette dernière est déjà exploitée dans diverses applications portables, comme les postes de radio, les lampes ou plus récemment les téléphones portables. Nous proposons dans cet article, une analyse expérimentale d'un générateur intégré dans un poste de radio afin d'en évaluer les avantages et inconvénients puis de proposer des améliorations

Can We Distinguish Biological Motions of Virtual Humans? Biomechanical and Perceptual Studies With Captured Motions of Weight Lifting

International audiencePerception of biological motions is a key issue in order to evaluate the quality and the credibility of motions of virtual humans. This paper presents a perceptual study to evaluate if human beings are able to accurately distinguish differences in natural lifting motions with various masses in virtual environments (VE), which is not the case. However, they reached very close levels of accuracy when watching to computer animations compared to videos. Still, quotes of participants suggest that the discrimination process is easier in videos of real motions which included muscles contractions, more degrees of freedom, etc. These results can be used to help animators to design efficient physically-based animations