Détection et Reconnaissance des Gestes Emblématiques

Session "Atelier IHMA"National audienceDans cette contribution, nous présentons un système de reconnaissance en ligne de gestes emblématiques et son utilisation pour le contrôle d'un robot mobile. Ce système comporte quatre sous-systèmes : un premier qui permet de détecter la personne et d'extraire les mouvements de la partie supérieure de cette personne. Un second, permet d'isoler les mouvements, une troisième permet de reconnaître un des mouvements appris a priori. Enfin le dernier module, traduit les mouvements reconnus en termes de contrôle d'un robot mobile à roues. Dans notre approche, nous avons surtout traité du problème de la généralisation : faire l'apprentissage sur une base réduite de personnes et utiliser cette connaissance pour reconnaître n'importe quelle personne, indépendamment de sa morphologie, de son âge, de son sexe et de son positionnement par rapport au capteur. Nous détaillons les résultats obtenus pour la reconnaissance ainsi que l'utilisation du système dans des scenarios de contrôle d'un robot

Elastocaloric effect in vulcanized natural rubber and natural/wastes rubber blends

Vulcanized natural/wastes rubber blends were prepared and their elastocaloric properties were analysed. A thermodynamic frame was used to discriminate the contributions of thermoelastic effects and strain induced crystallization/melting. The substitution of 20 wt% of the natural rubber matrix by waste rubber particles resulted in a maintain and even a slight improvement of heat exchanges (+10%), that we ascribed to a (i) high thermoelastic effect and a (ii) a high ability of the natural rubber matrix to crystallize due to a nucleation ability of the waste particles, both resulting from a strain amplification in the rubber phase due to undeformable carbon black aggregates in the waste particles. The materials coefficient of performance, COPmat, was estimated equal to 4.4 for the neat natural rubber and 3.8 for the blend containing 20 wt% of wastes due to larger mechanical energy originated from reinforcing effect of waste particles. Nonetheless, the elastocaloric (eC) abilities of these materials, especially their wide temperature spans (similar to those in films or polycrystals using rare earth elements) make these natural/waste rubber blends good candidates for application such as heating/cooling machines. Moreover, the partial replacement of natural rubber, a bio-source material showing risks of shortage, by industrial wastes rubber, place these blends as promising eco-friendly materials with high added value

Study on solar absorptance and thermal stability of solid particles materials used as TES at high temperature on different aging stages for CSP applications

The use of solid particles as heat transferfluid (HTF) presents a great potential to overcome drawbacks addressedin commercial Concentrated Solar Power (CSP) plants. The solid particles thermal energy storage (TES) systemallows achieving both high thermal performance at high temperature and low cost from the material perspective.The conversion efficiency of CSP solid particles-based systems at high temperatures strongly depends on theoptical properties and thermophysical properties of materials used both as HTF and as storage medium. Thepresent study is aimed to provide more experimental data and evidences of the potential in using particulatesolids for CSP application. The solar absorptance and the specific heat capacity of silicon carbide (SiC), silicasand (SiO2), and hematite (Fe2O3) are studied after different aging times at 750 °C and 900 °C. The solar ab-sorptance slightly increases over the aging process except for the silica sand, which decreases its absorptance inthefirst 100 h, reaching a plateau. After the aging treatment, the specific heat capacity is increased for both SiCand silica sand. However, for the iron oxide the specific heat capacity is lower after aging. The black siliconcarbide SiC is proven to be the best option to be used up to 900 °C as it shows the highest solar absorptance(96%) and the highest heat storage capacity