Monitoring a Realistic Virtual Hand using a Passive Haptic Device to Interact with Virtual Worlds

We present a prototype of a hands-on immersive peripheral device for controlling a virtual hand with high dexterity. This prototype is as easy as a mouse to use and allows the control of a high number of degrees of freedom (dofs) with tactile feedback. The goals corresponding to design issues, physiological behaviors, include the choice of sensors’ technology and their position on the device, low forces exerted while using the device, relevant multi-sensorial feedback, performance of achieved tasks

Discrete curvature approximations and segmentation of polyhedral surfaces

The segmentation of digitized data to divide a free form surface into patches is one of the key steps required to perform a reverse engineering process of an object. To this end, discrete curvature approximations are introduced as the basis of a segmentation process that lead to a decomposition of digitized data into areas that will help the construction of parametric surface patches. The approach proposed relies on the use of a polyhedral representation of the object built from the digitized data input. Then, it is shown how noise reduction, edge swapping techniques and adapted remeshing schemes can participate to different preparation phases to provide a geometry that highlights useful characteristics for the segmentation process. The segmentation process is performed with various approximations of discrete curvatures evaluated on the polyhedron produced during the preparation phases. The segmentation process proposed involves two phases: the identification of characteristic polygonal lines and the identification of polyhedral areas useful for a patch construction process. Discrete curvature criteria are adapted to each phase and the concept of invariant evaluation of curvatures is introduced to generate criteria that are constant over equivalent meshes. A description of the segmentation procedure is provided together with examples of results for free form object surfaces

Périphérique d'interaction apte à contrôler un élément de toucher et de préhension d'objets virtuels multidimensionnels

Ne pas le transférer sur HAL (déjà déposé sur HAL par le co-auteur (hors ENSAM))L’invention concerne un périphérique d’interaction (1) apte à contrôler un élément de toucher et de préhension d’objets virtuels multidimensionnels, comportant au moins deux modules d’interaction (20), chaque module d’interaction (20) étant destiné à être actionné par un doigt d’un opérateur et comportant un capteur de commande permettant de commander un déplacement, selon un nombre de degrés de liberté prédéterminé, d’une partie de l’élément de toucher et de préhension d’objets virtuels par déplacement en flexion/extension et/ou adduction/abduction du doigt de l’opérateur, et un vibreur apte à émettre une vibration lors du toucher et/ou du lâcher d’un objet virtuel par une partie dudit élément de toucher et de préhension d’objets virtuels, caractérisé en ce que chaque module d’interaction (20) est fixé audit périphérique par une jonction (40) en matériau amortissant

Interaction peripheral device capable of controlling an element for touching and grasping multidimensional virtual objects

An interaction peripheral device capable of controlling an element for touching and grasping multidimensional virtual objects, including at least two interaction modules, each interaction module being intended to be actuated by a finger of an operator and including a control sensor allowing control of displacement, according to a predetermined number of degrees of freedom, of a portion of the element for touching and grasping virtual objects by bending/extending and/or adduction/abduction displacement of the finger of the operator, and a vibrator able to emit a vibration upon touching and/or letting go of a virtual object by a portion of said element for touching and grasping virtual objects, characterized in that each interaction module is attached to said peripheral device through a connection in a damping material

Modélisation des trajectoires d'assemblage et de désassemblage associées aux liaisons fonctionnelles de produits

La modélisation des opérations de désassemblage fait intervenir de multiples données (géométriques, cinématiques, technologiques, ...) et nécessite de passer par une étape d'analyse des liaisons cinématiques entre composants au cours des différentes étapes de montage/démontage. Dans ce contexte, le but principal abordé ici est le développement d'un nouveau modèle capable de représenter tous les déplacements autorisés pour chaque couple de surfaces d'une liaison mécanique. Les différentes combinaisons possibles des contacts élémentaires sont étudiées afin de proposer un modèle général. Cette modèle est utilisé pour la simulation des opérations cinématiques nécessaires à l'assemblage et au désassemblage des produits lors du processus de production, des opérations de maintenance et en fin de cycle de vie. Un outil informatique, opérationnel sur OPEN CASCADE, est également proposé et présenté permettant de capter le type des contacts entre deux composants d'un ensemble mécanique

An add-on device to perform dexterous grasping tasks with a haptic feedback system

Achieving grasping tasks in real time with haptic feedback may require the control of a large number of degrees of freedom (DOFs) to model hand and finger movements. This is mandatory to grasp objects with dexterity. Here, a new device called HaptiHand is proposed that can be added to a haptic feedback arm and provide the user with enough DOFs so that he/she can intuitively and dexterously grasp an object, modify the virtual hand configuration and number of fingers with respect to the object while manipulating the object. Furthermore, this device is non-invasive and enables the user to apply forces on the fingers of the virtual hand. The HaptiHand lies inside the user’s hand so that the user can apply and release pressure on it in a natural manner that is transferred to the virtual hand using metaphors. The focus is placed on the description of the technology and structure of the HaptiHand to justify the choices and explain the behavior of the HaptiHand during object grasping and releasing tasks. This is combined with a short description of the models used.iLab Inria-Haptio

Incorporating free-form features in aesthetic and engineering product design: State-of-the-art report

The use of free-form shapes has become mainstream to design complex products that have to fulfil engineering requirements as well as aesthetic criteria. Even if today’s CAD systems can easily represent free-form shapes by means of NURBS surfaces, their definition and modification still require a deep knowledge and a great skill in the manipulation of the underlying mathematical models. The implemented free-form shapes design operators are time consuming and do not enable fast modifications. To overcome these limits, some researches have been undertaken to try to adapt the feature concept, successfully adopted for the design of regular shapes, in the free-form domain. It gives rise to a set of free-form features modelling strategies. This paper gathers together the state-of-the-art of these advances. The various approaches are depicted and compared with respect to a very precise set of criteria expressing the needs in aesthetic and engineering designs. The limits and future trends are presentedThese issues are recognized internationally as they are being part of the research topics of the AIM@SHAPE European Network of Excellenc

Propriétés topologiques pour la modélisation géométrique de domaines d'études comportant des singularités non-variétés

L’étude de comportement mécanique de structures et/ou d’écoulements s’appuie fréquemment sur des modèles géométriques perçus comme des assemblages de volumes, surfaces, lignes, connectés entre eux et comportant des singularités non-variétés. Une classification d’objets comportant des singularités non-variétés et des propriétés topologiques globales sont présentées pour accroître l’efficacité des modeleurs et la génération des contraintes de maillages