In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom. / May 2009

In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.

In large workspaces that do not fit on the screen space, users have to navigate to various regions outside the viewport to locate items of interest. Researchers have developed a variety of different navigation techniques to improve the performance of working with large workspaces. In this thesis I design, implement, and evaluate two novel navigation techniques to access off-screen content. I call these techniques Multiscale Window and Crystal Ball. The design of these two techniques was based on two hybrid interaction systems WinHop and Multiscale Zoom. Multiscale Window takes advantage of Multiscale Zoom to provide an overview of the context by incorporating full-detail object representations (proxies), and Crystal Ball is an improvement to WinHop. The implemented techniques were designed to alleviate the shortcomings of both hybrid techniques; Multiscale Zoom lacks the ability to provide detail information of overlapped proxies, and WinHop does not facilitate navigation to the off-screen region due to the animation. I evaluated the Multiscale Window and Crystal Ball techniques in two experiments. In the first experiment (N = 14) a Tablet PC with a digital pen as an input device was used. Results showed that there was no significant difference between Multiscale Window and Multiscale Zoom. However, Crystal Ball showed improved effects over WinHop in most tasks. The second experiment (N = 14) compared the same techniques as in experiment one, on a PC with a mouse as input device. The results indicated that subjects were faster with Crystal Ball than WinHop. Like the first experiment, Multiscale Window did not show any significant improvement over Multiscale Zoom.

Les machines parallèles (MPs) existent depuis plus d'un demi-siècle et ils ont fait l'objet d'études intensives. Par opposition avec leurs homologues de structure série, ces mécanismes sont constitués de plusieurs chaînes cinématiques qui relient la base fixe à la plateforme mobile. L'intérêt de ces architectures s'explique par les nombreux avantages qu'elles offrent, parmi lesquels: une rigidité élevée, un rapport important charge/poids global, des capacités dynamiques élevées en raison des masses en mouvement réduites (en particulier lorsque les actionneurs sont sur ou près de la base), une meilleure précision, des fréquences propres plus élevées, etc. Néanmoins, leur exploitation comme machines-outils reste timide et limitée, et le plus souvent elles ne dépassent pas le stade d'étude et de prototype de laboratoires universitaires ou de fabricants de machines-outils. Les principaux inconvénients qui entravent la généralisation des MPs dans l'industrie sont les suivants: un espace de travail limité, des débattements angulaires réduits, la présence de configurations singulières, la complexité de conception, les difficultés d'étalonnage, les problèmes causés par les collisions, la complexité du contrôle/commande (en particulier dans le cas de redondance à actionnement), etc. De plus, si les MPs ont rencontré un grand succès dans les applications de pick-and-place grâce à leur rapidité (capacité d'accélération), leur précision reste inférieure à ce qui a été prévu initialement. Par ailleurs, on trouve également des MPs de très précision, mais malheureusement avec de faibles performances dynamiques. En partant du constat précédant, cette thèse se concentre sur l'obtention de MPs avec un bon compromis entre rapidité et précision. Nous commençons par donner un aperçu de la bibliographie disponible concernant MPs et les avancées majeures dans ce domaine, tout en soulignant les limites de performance des MPs, ainsi que les limites des outils de conception classique. En outre, nous insistons sur les outils d'évaluation des performances, et montrons leurs limites dès qu'il s'agit de traiter le cas de la redondance ou l'hétérogénéité des degrés de liberté (ddl). En effet, si la synthèse architecturale est un point dur de la conception de MPs, la synthèse dimensionnelle reposant sur des indices de performances réellement significatifs l'est également. Par conséquent, de nouveaux indices de performance sont proposés pour évaluer la précision, les capacités cinétostatiques et dynamiques des manipulateurs de manière générale qui apportent des solutions aux difficultés évoquées ci-dessus. Par la suite, plusieurs nouvelles architectures 3T-2R et 3T-1R (T: signifie ddl en translation et R signifie un ddl de rotation) sont présentées, à savoir MachLin5, ARROW V1, et ARROW V2 et ses versions dérivées ARROW V2 M1 et M2. En outre, la synthèse dimensionnelle d'ARROW V2 M2 est réalisée, et les performances de la machine sont évaluées. Finalement, des améliorations futures concernant la précision sont proposées au regard de premiers résultats obtenus sur le prototype. / Parallel manipulators (PMs) have been there for more than half a century and they have been subject of intensive research. In comparison with their serial counterparts, PMs consist of several kinematic chains that connect the fixed base to the moving platform. The interest in such architectures is due to the several advantages they offer, among which we mention: high rigidity and payload-to-weight ratio, elevated dynamical capabilities due to reduced moving masses (especially when the actuators are at or near the base), better precision, higher proper frequencies, etc. Nevertheless, despite of the aforementioned merits, their exploitation as machine tools is still timid and limited, in which they most often do not exceed the research and prototyping stages at university laboratories and machine tool manufacturers. The main drawbacks that hinder the widespread of parallel kinematic machines (PKMs) are the following: limited operational workspace and tilting capacity, presence of singular configurations, design complexities, calibration difficulties, collision-related problems, sophistication of control (especially in the case of actuation redundancy), etc. Besides, though PMs have met a great success in pick-and-place applications, thanks to their rapidity (acceleration capacity), still their precision is less than what has been initially anticipated. On the other hand, extremely precise PMs exist, but unfortunately with poor dynamic performance. Starting from the aforementioned problematics, the current thesis focuses on obtaining PKMs with a good compromise between rapidity and precision. We begin by providing a survey of the available literature regarding PKMs and the major advancements in this field, while emphasizing the shortcomings on the level of design as well as performance. Moreover, an overview on the state of the art regarding performance evaluation is presented and the inadequacies of classical measures, when dealing with redundancy and heterogeneity predicaments, are highlighted. In fact, if finding the proper architectures is one of the prominent issues hindering PKMs' widespread, the performance evaluation and the criteria upon which these PKMs are dimensionally synthesized are of an equal importance. Therefore, novel performance indices are proposed to assess precision, kinetostatic and dynamic capabilities of general manipulators, while overcoming the aforementioned dilemmas. Subsequently, several novel architectures with 3T-2R and 3T-1R degrees of freedom (T and R signify translational and rotational degrees of freedom), namely MachLin5, ARROW V1, and ARROW V2 with its mutated versions ARROW V2 M1/M2, are presented. Furthermore, the dimensional synthesis of the executed PKM, namely ARROW V2 M2, is discussed with its preliminary performances and possible future enhancements, particularly regarding precision amelioration.