"We address the problem of performing complex tasks for a robot operating in changing environments. We propose two approaches to the following problem: 1) define task-specific cost functions for motion planning that represent path quality by learning from an expert's preferences and 2) using constraint-based representation of the task inside learning from demonstration paradigm. In the first approach, we generate a set of paths for a given task using a motion planner and collect data about their features (path length, distance from obstacles, etc.). We provide these paths to an expert as a set of pairwise comparisons. We then form a ranking of the paths from the expert's comparisons. This ranking is used as training data for learning algorithms, which attempt to produce a cost function that maps path feature values to a cost that is consistent with the expert's ranking. We test our method on two simulated car-maintenance tasks with the PR2 robot: removing a tire and extracting an oil filter. We found that learning methods which produce non-linear combinations of the features are better able to capture expert preferences for the tasks than methods which produce linear combinations. This result suggests that the linear combinations used in previous work on this topic may be too simple to capture the preferences of experts for complex tasks. In the second approach, we propose to introduce a constraint-based description of the task that can be used together with the motion planner to produce the trajectories. The description is automatically created from the demonstration by performing segmentation and extracting constraints from the motion. The constraints are represented with the Task Space Regions (TSR) that are extracted from the demonstration and used to produce a desired motion. To account for the parts of the motion where constraints are different a segmentation of the demonstrated motion is performed using TSRs. The proposed approach allows performing tasks on robot from human demonstration in changing environments, where obstacle distribution or poses of the objects could change between demonstration and execution. The experimental evaluation on two example motions was performed to estimate the ability of our approach to produce the desired motion and recover a demonstrated trajectory."

In the context of control, the motion of a legged robot is very challenging compared with traditional fixed manipulator. Recently, many researches have been conducted to control the motion of legged robot with different techniques. On the other hand, manipulation tasks have been addressed in many applications. These researches solved either the mobility or the manipulation problems, but integrating both properties in one system is still not available. In this thesis, a control algorithm is presented to control both locomotion and manipulation in a six legged robot. Landmines detection process is considered as a case study of this project to accelerate the mine detection operation by performing both walking and scanning simultaneously. In order to qualify the robot to perform more tasks in addition to the walking task, the joint redundancy of the robot is exploited optimally. The tasks are arranged according to their importance to high level of priority and low level of priority. A new task priority redundancy resolution technique is developed to overcome the effect of the algorithmic singularities and the kinematic singularity. The computational aspects of the solution are also considered in view of a real-time implementation. Due to the dynamic changes in the size of the robot motion space, the algorithm has the ability to make a trade-off between the number of achieved tasks and the imposed constraints. Furthermore, an appropriate hierarchy is imposed in order to ensure an accurate decoupling between the executed tasks. The dynamic effect of the arm on the overall performance of the robot is attenuated by reducing the optimisation variables. The effectiveness of the method is evaluated on a Computer Aided Design (CAD) model and the simulations of the whole operation are conducted using MATLAB and SimMechanics.

No description available.

This investigation has been carried out at the RoyalInstitute of Technology (KTH) in Stockholm. The main goal hasbeen to investigate the factors determining the production of asense of presence and reality in video mediated communication.Presenceis in these studies defines as the subjectiveexperience of being together in one place when one isphysically situated in another. Presence is an emergentproperty; it has no physicality, but arises as a mentalsensation. Special attention has been paid to spatial factors,embodiment issues, and narrative elements related to theproduction of presence. A context map has been used in order to model the semanticsof presence production and to visualize the relationshipsbetween the determining factors. The conclusions may besummarized as follows:     Knowledge about physical and extended spaces and bodiesand of the shifting of attention between these is importantin presence production.     Well planned design of physical and virtual spacesenhances the sense of presence.     Coherent design and production of mediated embodiment canenhance the sense of presence.     Conscious use of content characteristics, e.g., goodstorytelling, can enhance the sense of presence.     Different communication modes need the support ofdifferent combinations of presence production factors.     Even technically poorly mediated communication maysupport a sense of presence and reality if the storytellingis good.     The human sensory environment should be supported by asense of non-mediation, technological transparency, on theplane of discourse.     The results indicate that individual differencesinfluence the sense of presence and reality. The perception of video mediated communication evolves aspeople become daily users. People seem to intuitively begin tointerpret new types of mediated cues, adding what is missing incomparison to a real time physical communicationexperience. Keywords:Telepresence, presence, social presence,co-presence, concept modeling, virtual reality, person space,task space, narration, video mediated communication, videoconferencing.

<p>This investigation has been carried out at the RoyalInstitute of Technology (KTH) in Stockholm. The main goal hasbeen to investigate the factors determining the production of asense of presence and reality in video mediated communication.Presenceis in these studies defines as the subjectiveexperience of being together in one place when one isphysically situated in another. Presence is an emergentproperty; it has no physicality, but arises as a mentalsensation. Special attention has been paid to spatial factors,embodiment issues, and narrative elements related to theproduction of presence.</p><p>A context map has been used in order to model the semanticsof presence production and to visualize the relationshipsbetween the determining factors. The conclusions may besummarized as follows:</p><p>    Knowledge about physical and extended spaces and bodiesand of the shifting of attention between these is importantin presence production.</p><p>    Well planned design of physical and virtual spacesenhances the sense of presence.</p><p>    Coherent design and production of mediated embodiment canenhance the sense of presence.</p><p>    Conscious use of content characteristics, e.g., goodstorytelling, can enhance the sense of presence.</p><p>    Different communication modes need the support ofdifferent combinations of presence production factors.</p><p>    Even technically poorly mediated communication maysupport a sense of presence and reality if the storytellingis good.</p><p>    The human sensory environment should be supported by asense of non-mediation, technological transparency, on theplane of discourse.</p><p>    The results indicate that individual differencesinfluence the sense of presence and reality.</p><p>The perception of video mediated communication evolves aspeople become daily users. People seem to intuitively begin tointerpret new types of mediated cues, adding what is missing incomparison to a real time physical communicationexperience.</p><p><b>Keywords:</b>Telepresence, presence, social presence,co-presence, concept modeling, virtual reality, person space,task space, narration, video mediated communication, videoconferencing.</p>

Cette thèse est consacrée à l'étude de la manipulation et de la coordination robotique à deux bras ayant pour objectif le développement d'une approche unifiée dont différentes tâches seront décrites dans le même formalisme. Afin de fournir un cadre théorique compact et rigoureux, les techniques présentées utilisent les quaternions duaux afin de représenter les différents aspects de la modélisation cinématique ainsi que de la commande.Une nouvelle représentation de la manipulation à deux bras est proposée - l'espace dual des tâches de coopération - laquelle exploite l'algèbre des quaternions duaux afin d'unifier les précédentes approches présentées dans la littérature. La méthode est étendue pour prendre en compte l'ensemble des chaînes cinématiques couplées incluant la simulation d'un manipulateur mobile.Une application originale de l'espace dual des tâches de coopération est développée afin de représenter de manière intuitive les tâches principales impliquées dans une collaboration homme-robot. Plusieurs expérimentations sont réalisées pour valider les techniques proposées. De plus, cette thèse propose une nouvelle classe de tâches d'interaction homme-robot dans laquelle le robot contrôle tout les aspects de la coordination. Ainsi, au-delà du contrôle de son propre bras, le robot contrôle le bras de l'humain par le biais de la stimulation électrique fonctionnelle (FES) dans le cadre d'applications d'interaction robot / personne handicapée.Grâce à cette approche générique développée tout au long de cette thèse, les outils théoriques qui en résultent sont compacts et capables de décrire et de contrôler un large éventail de tâches de manipulations robotiques complexes. / This thesis is devoted to the study of robotic two-arm coordination/manipulation from a unified perspective, and conceptually different bimanual tasks are thus described within the same formalism. In order to provide a consistent and compact theory, the techniques presented herein use dual quaternions to represent every single aspect of robot kinematic modeling and control.A novel representation for two-arm manipulation is proposed—the cooperative dual task-space—which exploits the dual quaternion algebra to unify the various approaches found in the literature. The method is further extended to take into account any serially coupled kinematic chain, and a case study is performed using a simulated mobile manipulator. An original application of the cooperative dual task-space is proposed to intuitively represent general human-robot collaboration (HRC) tasks, and several experiments were performed to validate the proposed techniques. Furthermore, the thesis proposes a novel class of HRC taskswherein the robot controls all the coordination aspects; that is, in addition to controlling its own arm, the robot controls the human arm by means of functional electrical stimulation (FES).Thanks to the holistic approach developed throughout the thesis, the resultant theory is compact, uses a small set of mathematical tools, and is capable of describing and controlling a broad range of robot manipulation tasks.