Planification interactive de trajectoire en Réalité Virtuelle sur la base de données géométriques, topologiques et sémantiques

Pour limiter le temps et le coût de développement de nouveaux produits, l’industrie a besoin d’outils pour concevoir, tester et valider le produit avec des prototypes virtuels. Ces prototypes virtuels doivent permettre de tester le produit à toutes les étapes du Product Lifecycle Management (PLM). Beaucoup d’opérations du cycle de vie du produit impliquent la manipulation par un humain des composants du produit (montage, démontage ou maintenance du produit). Du fait de l’intégration croissante des produits industriels, ces manipulations sont réalisées dans un environnement encombré. La Réalité Virtuelle (RV) permet à des opérateurs réels d’exécuter ces opérations avec des prototypes virtuels. Ce travail de recherche introduit une nouvelle architecture de planification de trajectoire permettant la collaboration d’un utilisateur de RV et d’un système de planification de trajectoire automatique. Cette architecture s’appuie sur un modèle d’environnement original comprenant des informations sémantiques, topologiques et géométriques. Le processus de planification automatique de trajectoire est scindé en deux phases. Une planification grossière d’abord exploitant les données sémantiques et topologiques. Cette phase permet de définir un chemin topologique. Une planification fine ensuite exploitant les données sémantiques et géométriques détermine un trajectoire géométrique dans le chemin topologique défini lors de la planification grossière. La collaboration entre le système de planification automatique et l’utilisateur de RV s’articule autour de deux modes : en premier lieu, l’utilisateur est guidé sur une trajectoire pré-calculée à travers une interface haptique ; en second lieu, l’utilisateur peut quitter la solution proposée et déclencher ainsi une re-planification. L’efficacité et l’ergonomie des ces deux modes d’interaction est enrichie grâce à des méthodes de partage de contrôle : tout d’abord, l’autorité du système automatique est modulée afin de fournir à la fois un guidage prégnant lorsque l’utilisateur le suit, et plus de liberté à l’utilisateur (un guidage atténué) lorsque celui-ci explore des chemins alternatifs potentiellement meilleurs. Ensuite, lorsque l’utilisateur explore des chemins alternatifs, ses intentions sont prédites (grâce aux données géométriques associées aux éléments topologiques) et intégrées dans le processus de re-planification pour guider la planification grossière. Ce mémoire est organisé en cinq chapitres. Le premier expose le contexte industriel ayant motivé ces travaux. Après une description des outils de modélisation de l’environnement, le deuxième chapitre introduit le modèle multi-niveaux de l’environnement proposé. Le troisième chapitre présente les techniques de planification de trajectoire issues de la robotique et détaille le processus original de planification de trajectoire en deux phases développé. Le quatrième introduit les travaux précurseurs de planification interactive de trajectoire et les techniques de partage de contrôle existantes avant de décrire les modes d’interaction et les techniques de partage de contrôle mises en œuvre dans notre planificateur interactif de trajectoire. Enfin le dernier chapitre présente les expérimentations menées avec le planificateur de trajectoire et en analyse leurs résultats. ABSTRACT : To save time and money while designing new products, industry needs tools to design, test and validate the product using virtual prototypes. These virtual prototypes must enable to test the product at all Product Lifecycle Management (PLM) stages. Many operations in product’s lifecycle involve human manipulation of product components (product assembly, disassembly or maintenance). Cue to the increasing integration of industrial products, these manipulations are performed in cluttered environment. Virtual Reality (VR) enables real operators to perform these operations with virtual prototypes. This research work introduces a novel path planning architecture allowing collaboration between a VR user and an automatic path planning system. This architecture is based on an original environment model including semantic, topological and geometric information. The automatic path planning process split in two phases. First, coarse planning uses semantic and topological information. This phase defines a topological path. Then, fine planning uses semantic and geometric information to define a geometrical trajectory within the topological path defined by the coarse planning. The collaboration between VR user and automatic path planner is made of two modes: on one hand, the user is guided along a pre-computed path through a haptic device, on the other hand, the user can go away from the proposed solution and doing it, he starts a re-planning process. Efficiency and ergonomics of both interaction modes is improved thanks to control sharing methods. First, the authority of the automatic system is modulated to provide the user with a sensitive guidance while he follows it and to free the user (weakened guidance) when he explores possible better ways. Second, when the user explores possible better ways, his intents are predicted (thanks to geometrical data associated to topological elements) and integrated in the re-planning process to guide the coarse planning. This thesis is divided in five chapters. The first one exposes the industrial context that motivated this work. Following a description of environment modeling tools, the second chapter introduces the multi-layer environment model proposed. The third chapter presents the path planning techniques from robotics research and details the two phases path planning process developed. The fourth introduce previous work on interactive path planning and control sharing techniques before to describe the interaction modes and control sharing techniques involved in our interactive path planner. Finally, last chapter introduces the experimentations performed with our path planner and analyses their results

Interactive multimodal Path Planning in immersion

Recent studies have defined interactive path plan- ners for simulations involving a human operator. Such path planners enable a human operator to share control with an automatic planner and are based on Robotics and Virtual Reality (VR) methods. This paper proposes a novel architecture for this interactive planner. It enhances interaction with the user by adding topological and semantic representations to the purely geometric model traditionally used

Multi-layer path planning control for the simulation of manipulation tasks : involving semantics and topology

The industrial and research communities show increasing interest in using automatic path planning techniques for the simulation of manipulation tasks. Automatic path planning, largely explored by the robotics community over the past 30 years, computes the trajectories of robots or manipulated parts. However, as techniques developed so far use mostly purely (and large) geometric models, they may fail, produce a trajectory of little relevance, or lead to very high computation times, when facing complex or very constrained environments. Involving higher abstraction level information should lead to better relevance of the simulation. In this paper, we propose a novel path planning technique relying on an original multi-layer environment model containing geometrical, topological and semantic layers. A first coarse planning step at the topological and semantic layers and a fine planning step at the local and semantically characterized geometrical layer form the path planning process. Experimental full-scale results show increased control on the planning process, leading to much lower computation times and increased relevance of the computed trajectory

A multi-layer approach of interactive path planning for assisted manipulation in virtual reality

This work considers Virtual Reality (VR) applications dealing with objects manipulation (such as industrial product assembly, disassembly or maintenance simulation). For such applications, the operator performing the simulation can be assisted by path planning techniques from the robotics research field. A novel automatic path planner involving geometrical, topological and semantic information of the environment is proposed for the guidance of the user through a haptic device. The interaction allows on one hand, the automatic path planner providing assistance to the human operator, and on the other hand, the human operator to reset the whole planning process suggesting a better suited path. Control sharing techniques are used to improve the assisted manipulation ergonomics by dynamically balancing the automatic path planner authority according to the operator involvement in the task, and by predicting user’s intent to integrate it as early as possible in the planning process

A hierarchic approach for path planning in virtual reality.

This work considers path-planning processes for manipu- lation tasks such as assembly, maintenance or disassem- bly in a virtual reality (VR) context. The approach con- sists in providing a collaborative system associating a user immersed in VR and an automatic path planning process. It is based on semantic, topological and geometric representations of the environment and the planning process is split in two phases: coarse and fine planning. The automatic planner suggests a path to the user and guides him trough a haptic device. The user can escape from the proposed solution if he wants to explore a possible better way. In this case, the interactive system detects the users intention and computes in real-time a new path starting from the users guess. Experiments illustrate the different aspects of the approach: multi-representation of the en- vironment, path planning process, users intent prediction and control sharing

Couplages électro-thermo-mécaniques dans les modules de puissance fortement intégrés

Ce travail fait un bilan des actions de recherche menées dans le cadre de la thématique Electronique de puissance au sein du laboratoire Génie de Production de Tarbes (études expérimentales et modélisation)

A generic method of pulse width modulation applied to 3-Level T-type NPC inverter

This paper illustrates the application of a method based on the resolution of linear systems to an uncommon inverter switching cell. This study describes the mathematical model of the modulated inverter leg associated at the considered structure. The generalized inverse of a matrix is used to generate the admissible conduction rates. Among the modulation strategies obtained, three specific modulation schemes are proposed and discussed thanks to the generic mathematical standpoint used

Generic modeling of N-level pulse width modulation voltage source inverters and their control

A generic and mathematic tool is adapted and used for pulse width modulation inverter modelling and control. The model is developed on the elementary switching cell and finally extended to some N-level topologies and three-phase inverters. Based on the generalized inverses, the solution set of pulse width modulation carrier based scheme is highlighted. The degree of freedom highlighted for the modulation control are linked to the architecture described. A specific example is illustrated and based on a H-bridge 3 level topology

Generalized inverses applied to Pulse Width Modulation for static conversion: a first study

This paper points out the generic matrix approach to design Pulse Width Modulation strategies of three-phase Voltage Source Inverters. This well-known problem has infinitely many solutions, and many modulation methods already exist. This mathematical approach deserves to be explored by its rigor and mustidentify known but also new solution

A generic method of Pulse Width Modulation applied to three-phase 3-Level T-type NPC inverter

This paper illustrates the application of a solvingmethod of linear systems to a multilevel inverter. This study appliesa generic pulsewidth modulation (PWM) method to a multileveltopology. This method finally highlights some specific modulationschemes. First, the study describes the mathematical model of theinverter leg. The leg is made of three level T-type structure. Themodel is extended to the three-phase inverter. The generalized in-verse is used to generate the solution set of the conduction rates.Among the modulation strategies possible, three specific modula-tion schemes are proposed. The modulation schemes are applied tosimulate a PWM three-phase inverter. Finally, some experimentalresults complete the analysis