An autonomous and guided crowd in panic situations

This paper describes a model for simulating crowds in real time. We deal with the hierarchy of the crowd, groups and individuals. The groups are the most complex structure that can be controlled in different degrees of autonomy. The autonomy means that the virtual agents are independent of the user intervention. Depending on the complexity of the simulation, some simple behaviors can be sufficient to simulate crowds. Otherwise, more complicated behaviors rules can be necessary in order to improve the realism of the animation. We present two different ways for controlling crowd behaviors: - by defining behavior rules, to give intelligence to the agent. By providing an external control to guide crowd behaviors, this control is done by the user or by an autonomous agent called the guide. The main contribution of our approach is to combine these two ways of behaviors (autonomous, guide) in order to simulate the evacuation of a crowd in emergency situations. Many strategies of evacuation have been implemented and we will demonstrate that in most situations, the guided method decrease the average escape time and increase the chance of survival in emergency situations.Facultad de Informátic

Hierarchical model for real time simulation of virtual human crowds

This paper describes a model for simulating crowds of humans in real time. We deal with a hierarchy composed of virtual crowds, groups, and individuals. The groups are the most complex structure that can be controlled in different degrees of autonomy. This autonomy refers to the extent to which the virtual agents are independent of user intervention and also the amount of information needed to simulate crowds. Thus, depending on the complexity of the simulation, simple behaviors can be sufficient to simulate crowds. Otherwise, more complicated behavioral rules can be necessary and, in this case, it can be included in the simulation data in order to improve the realism of the animation. We present three different ways for controlling crowd behaviors: 1) by using innate and scripted behaviors, 2) by defining behavioral rules, using events and reactions, and 3) by providing an external control to guide crowd behaviors in real time. The two main contributions of our approach are: The possibility of increasing the complexity of group/agent behaviors according to the problem to be simulated and the hierarchical structure based on groups to compose a crowd

Automatic Speed Control For Navigation in 3D Virtual Environment

As technology progresses, the scale and complexity of 3D virtual environments can also increase proportionally. This leads to multiscale virtual environments, which are environments that contain groups of objects with extremely unequal levels of scale. Ideally the user should be able to navigate such environments efficiently and robustly. Yet, most previous methods to automatically control the speed of navigation do not generalize well to environments with widely varying scales. I present an improved method to automatically control the navigation speed of the user in 3D virtual environments. The main benefit of my approach is that automatically adapts the navigation speed in multi-scale environments in a manner that enables efficient navigation with maximum freedom, while still avoiding collisions. The results of a usability tests show a significant reduction in the completion time for a multi-scale navigation task

Freehand-Steering Locomotion Techniques for Immersive Virtual Environments: A Comparative Evaluation

Virtual reality has achieved significant popularity in recent years, and allowing users to move freely within an immersive virtual world has become an important factor critical to realize. The user’s interactions are generally designed to increase the perceived realism, but the locomotion techniques and how these affect the user’s task performance still represent an open issue, much discussed in the literature. In this article, we evaluate the efficiency and effectiveness of, and user preferences relating to, freehand locomotion techniques designed for an immersive virtual environment performed through hand gestures tracked by a sensor placed in the egocentric position and experienced through a head-mounted display. Three freehand locomotion techniques have been implemented and compared with each other, and with a baseline technique based on a controller, through qualitative and quantitative measures. An extensive user study conducted with 60 subjects shows that the proposed methods have a performance comparable to the use of the controller, further revealing the users’ preference for decoupling the locomotion in sub-tasks, even if this means renouncing precision and adapting the interaction to the possibilities of the tracker sensor

Locomotion in virtual environments and analysis of a new virtual walking device

This thesis investigates user interfaces for locomotion in virtual environments (VEs). It looks initially at virtual environments and user interfaces, then concentrates on locomotion interfaces, specifically on the Omni-Directional Treadmill (ODT) (Darken and Cockayne, 1997) and a new virtual walking device, LocoX, which was developed at the MOVES Institute, Naval Postgraduate School. It analyzes and compares the ODT and LocoX in terms of the application of human ability requirements (HARs). Afterwards, it compares the results of the analysis of the ODT and LocoX to real-world locomotion. The analysis indicates that LocoX, a new way of exploring virtual environments (VEs), provides a close match to real locomotion on some subtasks in VEs-- compared to the ODT--and produces relatively closer representation on some subtasks of real world locomotion. This thesis concludes that LocoX has great potential and that the locomotion provided is realistic enough to simulate certain kinds of movements inherent to real-world locomotion. LocoX still requires maturation and development, but is nonetheless a viable locomotion technique for VEs and future game-based simulations.http://archive.org/details/locomotioninvirt109452226Lieutenant Junior Grade, Turkish NavyApproved for public release; distribution is unlimited

Architecture et commande d'une interface de locomotion utilisant un mécanisme parallèle entraîné à l'aide de câbles

Ce mémoire présente le développement de l’architecture et des algorithmes de commande d’une interface de locomotion utilisant un mécanisme parallèle à câbles. Cette interface de locomotion permet d’améliorer l’expérience de la réalité virtuelle en recréant la topologie du monde virtuel. Tout d’abord, une revue de littérature sur les interfaces de locomotion est présentée. Par la suite, l’architecture globale du système est présentée. Les définitions de base sous-jacentes à la compréhension des algorithmes de commande ainsi que l’analyse cinématique du mécanisme sont ensuite présentées. L’architecture logicielle et les algorithmes de commande sont enfin présentés. Des améliorations au point de vue des mécanismes à câbles sont aussi présentées. Ces améliorations permettent d’améliorer la précision de la commande en position des mécanismes à câbles. Enfin, les résultats présentent l’aboutissement des travaux en montrant le fonctionnement d’un prototype à trois degrés de liberté de l’interface de locomotion réalisé.Québec Université Laval, Bibliothèque 201

Generating whole body movements for dynamics anthropomorphic systems under constraints

Cette thèse étudie la question de la génération de mouvements corps-complet pour des systèmes anthropomorphes. Elle considère le problème de la modélisation et de la commande en abordant la question difficile de la génération de mouvements ressemblant à ceux de l'homme. En premier lieu, un modèle dynamique du robot humanoïde HRP-2 est élaboré à partir de l'algorithme récursif de Newton-Euler pour les vecteurs spatiaux. Un nouveau schéma de commande dynamique est ensuite développé, en utilisant une cascade de programmes quadratiques (QP) optimisant des fonctions coûts et calculant les couples de commande en satisfaisant des contraintes d'égalité et d'inégalité. La cascade de problèmes quadratiques est définie par une pile de tâches associée à un ordre de priorité. Nous proposons ensuite une formulation unifiée des contraintes de contacts planaires et nous montrons que la méthode proposée permet de prendre en compte plusieurs contacts non coplanaires et généralise la contrainte usuelle du ZMP dans le cas où seulement les pieds sont en contact avec le sol. Nous relions ensuite les algorithmes de génération de mouvement issus de la robotique aux outils de capture du mouvement humain en développant une méthode originale de génération de mouvement visant à imiter le mouvement humain. Cette méthode est basée sur le recalage des données capturées et l'édition du mouvement en utilisant le solveur hiérarchique précédemment introduit et la définition de tâches et de contraintes dynamiques. Cette méthode originale permet d'ajuster un mouvement humain capturé pour le reproduire fidèlement sur un humanoïde en respectant sa propre dynamique. Enfin, dans le but de simuler des mouvements qui ressemblent à ceux de l'homme, nous développons un modèle anthropomorphe ayant un nombre de degrés de liberté supérieur à celui du robot humanoïde HRP2. Le solveur générique est utilisé pour simuler le mouvement sur ce nouveau modèle. Une série de tâches est définie pour décrire un scénario joué par un humain. Nous montrons, par une simple analyse qualitative du mouvement, que la prise en compte du modèle dynamique permet d'accroitre naturellement le réalisme du mouvement.This thesis studies the question of whole body motion generation for anthropomorphic systems. Within this work, the problem of modeling and control is considered by addressing the difficult issue of generating human-like motion. First, a dynamic model of the humanoid robot HRP-2 is elaborated based on the recursive Newton-Euler algorithm for spatial vectors. A new dynamic control scheme is then developed adopting a cascade of quadratic programs (QP) optimizing the cost functions and computing the torque control while satisfying equality and inequality constraints. The cascade of the quadratic programs is defined by a stack of tasks associated to a priority order. Next, we propose a unified formulation of the planar contact constraints, and we demonstrate that the proposed method allows taking into account multiple non coplanar contacts and generalizes the common ZMP constraint when only the feet are in contact with the ground. Then, we link the algorithms of motion generation resulting from robotics to the human motion capture tools by developing an original method of motion generation aiming at the imitation of the human motion. This method is based on the reshaping of the captured data and the motion editing by using the hierarchical solver previously introduced and the definition of dynamic tasks and constraints. This original method allows adjusting a captured human motion in order to reliably reproduce it on a humanoid while respecting its own dynamics. Finally, in order to simulate movements resembling to those of humans, we develop an anthropomorphic model with higher number of degrees of freedom than the one of HRP-2. The generic solver is used to simulate motion on this new model. A sequence of tasks is defined to describe a scenario played by a human. By a simple qualitative analysis of motion, we demonstrate that taking into account the dynamics provides a natural way to generate human-like movements