Collaborative robot control with hand gestures

Mestrado de dupla diplomação com a Université Libre de TunisThis thesis focuses on hand gesture recognition by proposing an architecture to control a collaborative robot in real-time vision based on hand detection, tracking, and gesture recognition for interaction with an application via hand gestures. The first stage of our system allows detecting and tracking a bar e hand in a cluttered background using skin detection and contour comparison. The second stage allows recognizing hand gestures using a Machine learning method algorithm. Finally an interface has been developed to control the robot over. Our hand gesture recognition system consists of two parts, in the first part for every frame captured from a camera we extract the keypoints for every training image using a machine learning algorithm, and we appoint the keypoints from every image into a keypoint map. This map is treated as an input for our processing algorithm which uses several methods to recognize the fingers in each hand. In the second part, we use a 3D camera with Infrared capabilities to get a 3D model of the hand to implement it in our system, after that we track the fingers in each hand and recognize them which made it possible to count the extended fingers and to distinguish each finger pattern. An interface to control the robot has been made that utilizes the previous steps that gives a real-time process and a dynamic 3D representation.Esta dissertação trata do reconhecimento de gestos realizados com a mão humana, propondo uma arquitetura para interagir com um robô colaborativo, baseado em visão computacional, rastreamento e reconhecimento de gestos. O primeiro estágio do sistema desenvolvido permite detectar e rastrear a presença de uma mão em um fundo desordenado usando detecção de pele e comparação de contornos. A segunda fase permite reconhecer os gestos das mãos usando um algoritmo do método de aprendizado de máquina. Finalmente, uma interface foi desenvolvida para interagir com robô. O sistema de reconhecimento de gestos manuais está dividido em duas partes. Na primeira parte, para cada quadro capturado de uma câmera, foi extraído os pontos-chave de cada imagem de treinamento usando um algoritmo de aprendizado de máquina e nomeamos os pontos-chave de cada imagem em um mapa de pontos-chave. Este mapa é tratado como uma entrada para o algoritmo de processamento que usa vários métodos para reconhecer os dedos em cada mão. Na segunda parte, foi utilizado uma câmera 3D com recursos de infravermelho para obter um modelo 3D da mão para implementá-lo em no sistema desenvolvido, e então, foi realizado os rastreio dos dedos de cada mão seguido pelo reconhecimento que possibilitou contabilizar os dedos estendidos e para distinguir cada padrão de dedo. Foi elaborado uma interface para interagir com o robô manipulador que utiliza as etapas anteriores que fornece um processo em tempo real e uma representação 3D dinâmica

3 dimensional computational fluid dynamic analysis of heat transfer in a scraped surface heat exchanger for bingham fluids

This study is focused on numerical analysis of the thermal behavior within a scraped surface heat exchanger (SSHE) for threshold fluids (Bingham fluids). An innovative SSHE is considered which includes helical ribbon, instead of using scrapers. Heat transfer simulations were carried out by means of specific CFD code to solve the three dimensional form of continuity, momentum and energy equations. In this work, the influence of dimensionless numbers (rotational Reynolds, axial Reynolds and Oldroyd numbers) on thermal behavior is studied. Numerical results show that for low axial Reynolds numbers compared to rotational Reynolds number (Reax/Rer <1), there is opposition between the axial components of velocity coming from the flow (ascending components) and axial components at the helical ribbon due to the mixing effect (descending components). However, for high axial Reynolds numbers (Reax/Rer >1), a parabolic-like flow is generated, indicating low degree of back mixing. Numerical results show also that an important heated zone was observed near the blades due to high blades rotating speed. The highest temperatures are found at the thermal boundary layer periodically disturbed by the helical ribbon. It appears that increasing the Oldroyd number produces a slight rise in the temperature field.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Performance Study of Scraped Surface Heat Exchanger with Helical Ribbons

In this work, numerical simulations were carried out using a specific CFD code in order to study the performance of an innovative Scraped Surface Heat Exchanger (SSHE) with helical ribbons for Bingham fluids (threshold fluids). The resolution of three-dimensional form of the conservation equations (continuity, momentum and energy equations) was carried out basing on the finite volume method (FVM). After studying the effect of dimensionless numbers (axial Reynolds, rotational Reynolds and Oldroyd numbers) on the hydrodynamic and thermal behaviors within SSHE, a parametric study was developed, by varying the width of the helical ribbon, the clearance between the stator wall and the tip of the ribbon and the number of turns of the helical ribbon, in order to improve the heat transfer inside the exchanger. The effect of these geometrical numbers on the hydrodynamic and thermal behaviors was discussed

Dossier : Sahara en mouvement

La période qui s’étend de la fin de l’année 2010 au début de 2011 constitue une rupture dans l’histoire des régimes autoritaires arabes. Le souffle des protestations sociales est parti de Tunisie et a emporté le régime de Ben Ali le 14 janvier 2011, puis celui de Moubarak, en Égypte, un mois plus tard. La Tunisie est donc au cœur de la seconde partie de L’Année du Maghreb qui traite de l’actualité maghrébine. Si l’onde de choc de la « révolution » tunisienne a occulté les enjeux sahariens, le Sahara constitue toujours un sujet de préoccupations des médias occidentaux : refuge d’al-Qaïda au Maghreb, cette région est analysée en termes strictement sécuritaires. Zone d’instabilité, le Sahara est perçu comme l’aire de jeu des terroristes et le lieu de passage des « hordes d’émigrés » en partance pour l’Europe. Le dossier de recherche de L’Année du Maghreb, coordonné par Dominique Casajus et ancré dans une perspective historique, donne du Sahara l’image beaucoup plus nuancée d’une région en mouvement. Aire géographique nourrissant les utopies techniciennes et littéraires, le Sahara a toujours été pris dans un réseau de relations, inséparables de ses marges. Alors que l’Europe de Schengen s’obstine à voir dans le Sahara un lieu vide dont il faut à tout prix empêcher qu’il ne soit traversé, il est en réalité une zone où poussent les villes, se déploient des réseaux commerçants transnationaux, se développent des échanges licites et des trafics illicites, s’affirment des mouvements politiques qui instrumentalisent les États et/ou sont instrumentalisés par eux. Éric Gobe, Rédacteur en chef et responsable scientifique de L’Année du Maghreb Dominique Casajus, Directeur de recherches au CNRS, Centre d’études des mondes africain