A importância da exploração marítima de petróleo, em especial para o Brasil, é indiscutível e risers são estruturas essenciais para essa atividade. Uma melhor compreensão da dinâmica dessas estruturas e dos esforços a que estão submetidas vem resultando de pesquisa constante na área, pesquisa que gera um grande volume de dados, freqüentemente descrevendo fenômenos de difícil compreensão. Este trabalho descreve o desenvolvimento de um ambiente que combina técnicas de realidade virtual (como ambientes 3D, navegação e estereoscopia) e visualização científica (como mapeamento de cores, deformações e glifos) para facilitar a visualização desses dados. O ambiente, batizado como RiserView, permite a montagem de cenas tridimensionais compostas por risers, relevo do solo, superfície marítima, embarcações, bóias e outras estruturas, cada um com sua dinâmica própria. Permite ainda a visualização do escoamento para que a formação de vórtices na vizinhança dos risers e a interação fluido-mecânica resultante possam ser estudadas. O usuário pode controlar parâmetros da visualização de cada elemento e da animação da cena, bem como navegar livremente por ela. Foi desenvolvido também um algoritmo de baixo custo computacional (graças a simplificações possíveis devido à natureza do problema) para detecção e exibição em tempo real de colisões entre risers. O Processo Unificado foi adaptado para servir como metodologia para o projeto e implementação do aplicativo. O uso do VTK (API gráfica e de visualização científica) e do IUP (API para desenvolvimento de interfaces com o usuário) simplificou o desenvolvimento, principalmente para produzir um aplicativo portável para MS-Windows e Linux. Como opções de projeto, a visualização científica e a velocidade na renderização das cenas são privilegiadas, ao invés do realismo e da agilidade na interação com o usuário. As conseqüências dessas escolhas, bem como alternativas, são discutidas no trabalho. O uso do VTK e, através dele, do OpenGL permite que o aplicativo faça uso dos recursos disponíveis em placas gráficas comerciais para aumentar sua performance. Em sua versão atual a tarefa mais custosa para o RiserView é a atualização das posições de risers, principalmente descritos no domínio da freqüência, mas o trabalho discute aprimoramentos relativamente simples para minimizar esse problema. Apesar desses (e de outros) aprimoramentos possíveis, discutidos no trabalho, o ambiente mostra-se bastante adequado à visualização dos risers e de sua dinâmica bem como de fenômenos e elementos a eles associados. / The importance of offshore oil exploration, especially to Brazil, cannot be argued and risers are crucial structures for this activity. A better understanding of the dynamics of these structures and of the efforts to which they are subject has been resulting from constant research in the field, research that generates a large volume of data, often describing phenomena of difficult comprehension. This work describes the development of a software environment that combines elements of virtual reality (3D environments, navigation, stereoscopy) and scientific visualization techniques (such as color mapping, deformations and glyphs) to improve the understanding and visualization of these data. The environment, christened RiserView, allows the composition of tridimensional scenes including risers, the floor and surface of the ocean and ships, buoys and other structures, each with its own dynamics. It also allows the visualization of the flow in the neighborhood of the risers so that vortex shedding and the resulting fluid-mechanic interactions may be studied. The user may control parameters of the scene animation and of the visualization for each of its elements, as well as navigate freely within the scene. An algorithm of low computational cost (thanks to simplifications possible due to the nature of the problem), for the detection and exhibition of collisions between risers in real time, was also developed. The Unified Process was adapted to guide the software's project and implementation. The use of VTK (a scientific visualization and graphics API) and IUP (a user interface development API) simplified the development, especially the effort required to build an application portable to MS-Windows and Linux. As project choices, scientific visualization and the speed in rendering scenes in real time were given higher priority than realism and the agility in the user interaction, respectively. The consequences of these choices, as well as some alternatives, are discussed. The use of VTK and, through it, OpenGL, allows the application to access features available in most commercial graphics cards to increase performance. In its current version, the most costly task for RiserView are the calculations required to update riser positions during animation, especially for risers described in the frequency domain, but the work discusses relatively simple improvements to minimize this problem. Despite these (and other) possible improvements discussed in the work, the application proves quite adequate to the visualization of risers and their dynamics, as well as of associate elements and phenomena.

Cette thèse se place dans un contexte médical de traitements oncologiques, plus particulièrement en protonthérapie robotisée. L’objectif de cette thèse, réalisée sous contrat Cifre avec la société LEONI CIA Cable Systems, est le développement d’une commande en co-manipulation sûre dédiée à un robot médical sériel. Cette commande doit permettre à un opérateur de manipuler intuitivement et précisément un robot de grande inertie positionneur de patients. Les contributions portent sur deux axes, d’une part le développement et l’implémentation sur le robot Orion de l’entreprise LEONI CIA Cable Systems d’une commande en admittance ainsi que la comparaison de trois dispositifs haptiques, et d’autre part le développement d’un mécanisme de détection de collisions proprioceptif permettant l’amélioration de la sécurité de fonctionnement. À partir d’une revue de la littérature concernant les commandes compliantes, nous avons développé et implémenté une commande en admittance dédiée au robot Orion en tenant compte de la discrétisation de la commande par le contrôleur spécifique de ce robot. Une expérience de comparaison sur le robot nous a permis d’identifier le dispositif haptique le mieux adapté au cas clinique considéré. Après une étude de l’état de l’art des mécanismes de détection de collisions, une approche fréquentielle de la modélisation du couple axial prenant en compte les rapports de réduction élevés et de technologie différente du robot a été proposée. Elle permet de modéliser finement le couple théoriquement fourni par les moteurs ; celui-ci est ensuite comparé avec la mesure du couple réellement produit afin de détecter une éventuelle collision. / This PhD thesis takes place in a medical context of oncological treatments, more particularly in robotised protontherapy. The objective of this thesis, carried out under a CIFRE contract with LEONI CIA Cable Systems, is the development of a safe comanipulation control dedicated to a serial medical robot. This control law should allow an operator to intuitively and precisely manipulate a robot of high inertia for accurate patients positioning. The contributions of this thesis focus on the development and implementation of an admittance-controlled Orion robot from LEONI CIA Cable Systems and the comparison of three haptic devices, and on the other hand, on the development of a proprioceptive collision detection mechanism allowing the improvement of operational safety. Based on a review of the literature on compliant controls, we have developed and implemented an admittance control approach dedicated to the Orion robot, taking into account the discretization of the control by the controller specific to this robot. A comparison experiment on the robot allowed us to identify the haptic device best suited to the clinical case considered. Based on a state of the art of collision detection mechanisms analysis, a frequency approach of the modeling of the axial torque taking into account the high reduction ratios and different robot technology has been proposed. It allows us to finely model the torque theoretically provided by the motors ; The latter is then compared with the measurement of the torque actually produced in order to detect a possible collision.

<p>The unchangeable need of securing and locating parts during different manufacturing processes turned the fixtures to key elements in many part production industries. The iterations between design engineers and manufacturing planners because of late collision detection of the part/fixtures with robots cost a lot of time and money. The lead-time can be reduced by developing tools and/or methods for early verification of the fixtures during the simultaneous engineering phase. Different aspects of fixture designing, modeling and simulating is investigated as a base step to recognize the best practice work to do fixture planning in Process Simulate integrated PLM environment. The aim of the project is to use Process Simulate to design and validate modular fixtures at the same time and in a single environment. It also aims to investigate the possibility of adding kinematics, sensors, and actuating signals to the fixtures and utilize them to model the fixture behavior in a larger simulation study. The project narrows down its focus on the fixtures designed for robotic applications specifically in Automotive Body in White lines without losing generality. The document type stated at the title page and in the header of this page is master thesis work.</p>

The unchangeable need of securing and locating parts during different manufacturing processes turned the fixtures to key elements in many part production industries. The iterations between design engineers and manufacturing planners because of late collision detection of the part/fixtures with robots cost a lot of time and money. The lead-time can be reduced by developing tools and/or methods for early verification of the fixtures during the simultaneous engineering phase. Different aspects of fixture designing, modeling and simulating is investigated as a base step to recognize the best practice work to do fixture planning in Process Simulate integrated PLM environment. The aim of the project is to use Process Simulate to design and validate modular fixtures at the same time and in a single environment. It also aims to investigate the possibility of adding kinematics, sensors, and actuating signals to the fixtures and utilize them to model the fixture behavior in a larger simulation study. The project narrows down its focus on the fixtures designed for robotic applications specifically in Automotive Body in White lines without losing generality. The document type stated at the title page and in the header of this page is master thesis work.

In recent years, researchers have developed virtual environments, which allow more realistic human-computer interactions and have become increasingly popular for engineering applications such as computer-aided design and process evaluation. For instance, the demand for product service, remanufacture, and recycling has forced companies to consider ease of assembly and disassembly during the design phase of their products. Evaluating these processes in a virtual environment during the early stages of design not only increases the impact of design modifications on the final product, but also eliminates the time, cost, and material associated with the construction of physical prototypes. Although numerous virtual environments for assembly analysis exist or are under development, many provide only visual feedback. A real-time haptic simulation test bed for the analysis of assembly and disassembly operations has been developed, providing the designer with force and tactile feedback in addition to traditional visual feedback. The development such a simulation requires the modeling of collisions between virtual objects, which is a computationally expensive process. Also, the demands of a real-time simulation incorporating haptic feedback introduce additional complications for reliable collision detection. Therefore, the first objective of this work was to discover ways in which current collision detection libraries can be improved or supplemented to create more robust interaction between virtual objects. Using the simulation as a test bed, studies were then conducted to determine the potential usefulness of haptic feedback for analysis of assembly and disassembly operations. The following significant contributions were accomplished: (1) a simulation combining the strengths of an impulse-based simulation with a supplemental constraint maintenance scheme for modeling object interactions, (2) a toolkit of supplemental techniques to support object interactions in situations where collision detection algorithms commonly fail, (3) a haptic assembly and disassembly simulation useful for experimentation, and (4) results from a series of five experimental user studies with the focus of determining the effectiveness of haptic feedback in such a simulation. Additional contributions include knowledge of the usability and functionality of current collision detection libraries, the limitations of haptic feedback devices, and feedback from experimental subjects regarding their comfort and overall satisfaction with the simulation.

Susidūrimų paieška - tai dviejų ar daugiau objektų susikirtimo radimas. Praktikoje susidūrimų paieška taikoma šiose srityse: kompiuteriniuose žaidimuose, netiesinėje baigtinių elementų analizėje, dalelių hidrodinamikoje, daugiafunkcinės dinamikos analizėje, įvairiose fizikos simuliacijose ir kt. Egzistuoja daugybė susidūrimų paieškos algoritmų, iš kurių populiariausi yra erdvinio skaidymo, hierarchinio struktūrizavimo ir atrinkimo bei rūšiavimo metodai. Šiame darbe yra tiriamas šių algoritmų veikimas ant CPU (Central processing unit) ir ant GPU (Graphics processing unit), analizuojami susidūrimų paieškos nustatymo būdai bei nagrinėjamos pasirinktų algoritmų veikimo spartinimo galimybės panaudojant CUDA (Compute Unified Device Architecture) technologiją. Ši technologija yra Nvidia sukurta nauja duomenų apdorojimo architektūra išnaudojanti grafinio procesoriaus resursus bendro pobūdžio skaičiavimams. Darbe iškeltų tikslų pasiekimui yra realizuotos kelios bazinės algoritmų versijos, jų pritaikymo lygiagretiems skaičiavimams galimybės ir taip pat atliekami bazinių algoritmų laiko, reikalingo skaičiavimams atlikti, grafinio procesoriaus atminties sąnaudos bei įvairių veikimo laiką įtakojančių faktorių tyrimai. Darbo pabaigoje aptariami lygiagretaus programavimo privalumai pritaikant nagrinėjamai temai. Šiame darbe atlikti tyrimai parodė, jog perduodant skaičiavimus į GPU pasiekiamas 200 kartų didesnis nagrinėjamų algoritmų našumas negu atliekant skaičiavimus naudojant CPU. / Collision detection is a well-studied and active research field where the main problem is to determine if one or more objects collide with each other in 3D virtual space. Collision detection is an issue affecting many different fields of study, including computer animation, physical-based simulation, robotics, video games and haptic applications. There is a big variety of collision detection algorithms of witch spatial subdivision, octree and sort and sweep are three of them. In this document we provide a short summary of collision detection algorithms, but the main focus will be on analyzing and increasing their performance working on CPU (orig. Central processing unit) and GPU (orig. Graphics processing unit) separately by making use of CUDA (orig.Compute Unified Device Architecture) technology. This technology is a part of Nvidia, witch helps the use of graphics processor for general-purpose computation. Main goal of this research is achieved by performing analysis of implemented spatial subdivision, octree and sort and sweep algorithms. This analysis consists of both general performance, parallelization performance and various performance affecting factors analyses. At the end of the document, the advantages of parallel programming adapted to the present subject are discussed.

The need for efficient interference detection frequently arises in computer graphics, robotics, virtual prototyping, surgery simulation, computer games, and visualization. To prevent bodies passing directly through each other, the simulation system must be able to track touching or intersecting geometric primitives. In interactive simulations, in which millions of geometric primitives may be involved, highly efficient collision detection algorithms are necessary. For these reasons, new adaptive collision detection algorithms for rigid and different types of deformable polygon meshes are proposed in this thesis. The solutions are based on adaptive bounding volume hierarchies. For deformable body simulation, different refit and reconstruction schemes to efficiently update the hierarchies as the models deform are presented. These methods permit the models to change their entire shape at every time step of the simulation. The types of deformable models considered are (i) polygon meshes that are deformed by arbitrary vertex repositioning, but with the mesh topology preserved, (ii) models deformed by linear morphing of a fixed number of reference meshes, and (iii) models undergoing completely unstructured relative motion among the geometric primitives. For rigid body simulation, a novel type of bounding volume, the slab cut ball, is introduced, which improves the culling efficiency of the data structure significantly at a low storage cost. Furthermore, a solution for even tighter fitting heterogeneous hierarchies is outlined, including novel intersection tests between spheres and boxes as well as ellipsoids and boxes. The results from the practical experiments indicate that significant speedups can be achieved by using these new methods for collision queries as well as for ray shooting in complex deforming scenes.

Five-axis CNC milling machine tools bring great facility to produce complex workpieces with increased dimensional accuracy and better surface quality in shorter machining times. However, kinematics of five-axis machine tools has a complex form which makes it difficult to operate these machine tools properly. The difficulty arises from the complexity of NC-Code generation and tool path verification. Collision of machine tool or setup components with each other is a severe problem in five-axis machining operations and usually results from inadequate postprocessors or insufficient collision checking due to absence of well-prepared simulation and verification programs. Five-axis CNC machine tool owners may get rid of this problem by purchasing commercial postprocessors, simulation and verification programs. However, these programs are expensive and small and medium enterprises (SME&rsquo / s) usually cannot afford the costs of these programs. In the related libraries of commercial programs, there is great number of CNC machine tools, which is generally unnecessary for SME&rsquo / s. An alternative to overcome this problem is to develop particular program, which is capable of postprocessing, simulating and verifying milling operations, for each certain five-axis CNC machine tool. In this study, a software named &ldquo / Manus 1.0&rdquo / , which performs postprocessing and simulation processes, has been developed for the high speed &ldquo / Mazak Variaxis 630-5X&rdquo / CNC five-axis machine tool, located in METU-BILTIR Center. Moreover, tool path verification algorithms have been developed to detect collisions. The software has been written in Borland C++ Builder5.0. The developed program has been tested in sample milling operations and satisfactory results have been achieved.

Drastic changes in aircraft operational requirements and the emergence of new enabling technologies often occur symbiotically with advances in technology inducing new requirements and vice versa. These changes sometimes lead to the design of vehicle concepts for which no prior art exists. They lead to revolutionary concepts. In such cases the basic form of the vehicle geometry can no longer be determined through an ex ante survey of prior art as depicted by aircraft concepts in the historical domain. Ideally, baseline geometries for revolutionary concepts would be the result of exhaustive configuration space exploration and optimization. Numerous component layouts and their implications for the minimum external dimensions of the resultant vehicle would be evaluated. The dimensions of the minimum enclosing envelope for the best component layout(s) (as per the design need) would then be used as a basis for the selection of a baseline geometry. Unfortunately layout design spaces are inherently large and the key contributing analysis i.e. collision detection, can be very expensive as well. Even when an appropriate baseline geometry has been identified, another hurdle i.e. vehicle scaling has to be overcome. Through the design of a notional Cessna C-172R powered by a liquid hydrogen Proton Exchange Membrane (PEM) fuel cell, it has been demonstrated that the various forms of vehicle scaling i.e. photographic and historical-data-based scaling can result in highly sub-optimal results even for very small O(10-3) scale factors. There is therefore a need for higher fidelity vehicle scaling laws especially since emergent technologies tend to be volumetrically and/or gravimetrically constrained when compared to incumbents. The Configuration-space Exploration and Scaling Methodology (CESM) is postulated herein as a solution to the above-mentioned challenges. This bottom-up methodology entails the representation of component or sub-system geometries as matrices of points in 3D space. These typically large matrices are reduced using minimal convex sets or convex hulls. This reduction leads to significant gains in collision detection speed at minimal approximation expense. (The Gilbert-Johnson-Keerthi algorithm is used for collision detection purposes in this methodology.) Once the components are laid out, their collective convex hull (from here on out referred to as the super-hull) is used to approximate the inner mold line of the minimum enclosing envelope of the vehicle concept. A sectional slicing algorithm is used to extract the sectional dimensions of this envelope. An offset is added to these dimensions in order to come up with the sectional fuselage dimensions. Once the lift and control surfaces are added, vehicle level objective functions can be evaluated and compared to other designs. For each design, changes in the super-hull dimensions in response to perturbations in requirements can be tracked and regressed to create custom geometric scaling laws. The regressions are based on dimensionally consistent parameter groups in order to come up with dimensionally consistent and thus physically meaningful laws. CESM enables the designer to maintain design freedom by portably carrying multiple designs deeper into the design process. Also since CESM is a bottom-up approach, all proposed baseline concepts are implicitly volumetrically feasible. Furthermore the scaling laws developed from custom data for each concept are subject to less design noise than say, regression based approaches. Through these laws, key physics-based characteristics of vehicle subsystems such as energy density can be mapped onto key system level metrics such as fuselage volume or take-off gross weight. These laws can then substitute some historical-data based analyses thereby improving the fidelity of the analyses and reducing design time.

Avec le développement de systèmes robotiques avancés et de tâches de téléopération complexes, le besoin pour la réalisation de simulations en amont des opérations sur les systèmes réels se fait de plus en plus ressentir. Cela concerne en particulier les tests de faisabilité, d’entrainement d’opérateurs humains, de planification de mouvement, etc. Ces simulations doivent généralement être réalisées avec une précision importante des phénomènes physiques, notamment si l’opérateur humain est supposé faire face aux mêmes comportements mécaniques dans le monde réel que sur la scène virtuelle. La détection de collision, c’est à dire le calcul de points de contact et des normales de contact entre des objets rigides en mouvement et susceptibles d’interagir, occupe une portion significative des temps de calcul pour ce type de simulations. La précision ainsi que le niveau de continuité de ces informations de contact sont d’importance premières afin de produire des comportements réalistes des objets simulés. Cependant, la qualité des informations de contact ainsi calculées dépend fortement de la représentation géométrique des parties de la scène virtuelle directement impliquées dans la simulation mécanique. D'une part, les représentations géométriques basées sur des volumes discrets ou des tessellations permettent une génération de contacts extrêmement rapide, mais en contrepartie introduisent des artefacts numériques dus à l’approximation des formes en contact. D'autre part, l’utilisation de représentations surfaciques lisses (composées de courbes et surfaces lisses) produites par les modeleurs CAO permet d’éliminer ce problème d’approximations. Cependant, ces approches sont actuellement considérées trop lentes en pratique pour des applications en temps réel.Cette thèse est dédiée au développement d’une premier framework de détection de collision entre solides modélisés par représentation surfacique lisses suffisamment efficace pour offrir des performances temps-réel pour certaines applications industrielles nécessitant un niveau de précision élevé. Ces applications prennent typiquement la forme de la simulation d’opérations d’insertion avec faible jeu. L’approche proposée est basée sur une hiérarchie de volumes englobants et tire profit de caractéristiques clef des composants mécaniques industriels dont les surfaces sujettes à des contacts fonctionnels sont généralement modélisées par des surfaces canoniques (cylindres, sphères, cônes, plans, tores). Les contacts sur des surfaces d’interpolation telles que les NURBS sont généralement accidentels et rencontrés lors d’opérations de maintenance et de fabrication. Cette hiérarchie de volumes englobants est améliorée par l’identification d'entités supermaximales afin d’éviter la localisation redondante de points de contacts entre surfaces canoniques parfois découpées en plusieurs entités distinctes. De plus, le concept de cônes polyédrique de normales est défini afin d’établir des bornes de normales plus précises que les cônes de normales de révolution existants. Additionnellement, le framework ainsi développé est étendu afin de supporter des configurations incluant des câbles modélisés par des courbes de Bézier dilatées. Enfin, l’exploitation de la cohérence temporelle, ainsi que la parallélisation de l’ensemble du framework permet l’exécution en temps réel de certains scénarios industriels. / With the development of advanced robotic systems and complex teleoperation tasks, the need to perform simulations before operating on physical systems becomes of increasing interest for feasibility tests, training of the human operators, motion planning, etc. Such simulations usually need to be performed with great accuracy of physical phenomena if, e.g., the operator is expected to face the same ones in the real world and in the virtual scene. Collision detection, i.e., the computation of contact points and contact normals between interacting rigid bodies, occupies a time-consuming part of such a physical simulation. The accuracy and smoothness of such contact information is of primary importance to produce a realistic behavior of the simulated objects. However, the quality of the computed contact information strongly depends on the geometric representation of the parts of the virtual scene directly involved in the mechanical simulation. On the one hand, discrete volumes-based and tessellation-based geometric representations allow very fast contacts generation at the cost of the potential introduction of numerical artifacts due to the approximation of the interacting geometrical shapes. On the other hand, the use of boundary representations (issued by CAD modelers) composed of smooth curve and surfaces removes this approximation problem but is currently considered being too slow in practice for real-time applications.This Ph.D focuses on developing a first complete collision detection framework on solids with smooth boundary representations that achieves real-time performances. Our goal is to allow the real-time simulation of industrial scenarios that require a high level of accuracy. Typical applications are insertion tasks with small mechanical clearances. The proposed approach is based on a bounding-volume hierarchy and takes advantage of key features of industrial mechanical components which are often modeled with surfaces describing functional contacts with canonical surfaces (cylinder, sphere, cone, plane, torus) while contacts over free-form surfaces like B-Splines are mostly accidental and encountered during operations of maintenance and manufacturing. We augment this hierarchy with the identification of supermaximal features in order to avoid redundant exact localization of contact points on canonical surfaces that may be represented as distinct features of the CAD model. In addition, we define polyhedral normal cones that offer tighter bounds of normals than existing normal cones of revolution. Moreover, we extend our method to handle configurations that involve beams modeled as deformable dilated Bézier curves. Finally, parallelization of the full approach allows industrial scenarios to be executed in real-time.