On the Collaboration of an Automatic Path-Planner and a Human User for Path-Finding in Virtual Industrial Scenes

This paper describes a global interactive framework enabling an automatic path-planner and a user to collaborate for finding a path in cluttered virtual environments. First, a collaborative architecture including the user and the planner is described. Then, for real time purpose, a motion planner divided into different steps is presented. First, a preliminary workspace discretization is done without time limitations at the beginning of the simulation. Then, using these pre-computed data, a second algorithm finds a collision free path in real time. Once the path is found, an haptic artificial guidance on the path is provided to the user. The user can then influence the planner by not following the path and automatically order a new path research. The performances are measured on tests based on assembly simulation in CAD scenes

Apport des méthodes de planification automatique dans les simulations interactives d'industrialisation et de maintenance en réalité virtuelle

Ce document explore l'utilisation de méthodes de planification automatique dans des simulations interactives. Lors de simulations de montage et de démontage de composants industriels en environnement virtuel, l'utilisateur peut nécessiter une assistance. Cette assistance est réalisée par l'utilisation d'une solution de planification de trajectoire en temps réel. Cette solution permet la construction interactive d'une chemin par la combinaison de l'avis de l'utilisateur avec la performance de planificateurs automatiques. ABSTRACT : This PhD thesis explores the use of motion planning methods in interactive simulations. In the context of assembling and disassembling simulations of industrial components using haptic devices, the user may require assistance to find collision free paths. This assistance can be provided using real time interactive path planning methods. Our solution allows an interactive construction of free paths by combining the opinion of the user with the performance of fast modified automatic path planners

Constitutive relation error estimators for (visco) plastic finite element analysis with softening

International audienceA posteriori error estimators based on constitutive relation residuals have been developed for 20 years, in particular at Cachan. This approach has a strong physical meaning and is quite general. Here, we introduce an extended constitutive relation error estimators family able to measure the quality of finite element computations of structures which exhibit plastic/viscoplastic behavior with softening. These measures take into account, over the studied time interval, all the classical error sources involved in the computation: the space discretization (the mesh), the time discretization and the iterative technique used to solve the nonlinear discrete problem

Lytic xylan oxidases from wood-decay fungi unlock biomass degradation

Wood biomass is the most abundant feedstock envisioned for the development of modern biorefineries. However, the cost-ef-fective conversion of this form of biomass into commodity products is limited by its resistance to enzymatic degradation. Here we describe a new family of fungal lytic polysaccharide monooxygenases (LPMOs) prevalent among white-rot and brown-rot basidiomycetes that is active on xylans—a recalcitrant polysaccharide abundant in wood biomass. Two AA14 LPMO members from the white-rot fungus Pycnoporus coccineus substantially increase the efficiency of wood saccharification through oxida-tive cleavage of highly refractory xylan-coated cellulose fibers. The discovery of this unique enzyme activity advances our knowledge on the degradation of woody biomass in nature and offers an innovative solution for improving enzyme cocktails for biorefinery applications

A new a posteriori error estimation for nonlinear time-dependent finite element analysis

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Adaptive control for finite element analysis in plasticity

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Collaborative VR-CAD for Industrial Product Design: CAD Parameter Modification with 3D Interaction on Heterogeneous Immersive Platforms

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Virtual Workspace Positioning Techniques during Teleportation for Co-located Collaboration in Virtual Reality using HMDs

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