No description available.

No description available.

Shared control is a technique to provide interactive autonomy in a telerobotic task, replacing the requirement for pure teleoperation where the operator's intervention is unnecessary or even undesirable. In this thesis, a geometrically correct theory of shared control for teleoperation is developed using differential geometry. The autonomous function proposed is force control. In shared control, the workspace is commonly partitioned into a "position domain" and a "force domain". This computational process requires the use of a metric. In the context of manifolds, these are known as Riemannian metrics. The switching matrix is shown to be equivalent to a filter which embodies a Riemannian metric form. However, since the metric form is non-invariant, it is shown that the metric form must undergo a transformation if the measurement reference frame is moved. If the transformation is not made, then the switching matrix fails to produce correct results in the new measurement frame. Alternatively, the switching matrix can be viewed as a misinterpretation of a projection operator. Again, the projection operator needs to be transformed correctly if the measurement reference frame is moved. Many robot control architectures preclude the implementation of robust force control. However, a compliant device mounted between the robot wrist and the workpiece can be a good alternative in lieu of explicit force control. In this form of shared control, force and displacement are regulated by control of displacement only. The geometry of compliant devices is examined in the context of shared control and a geometrically correct scheme for shared control is derived. This scheme follows naturally from a theoretical analysis of stiffness and potential energy. This thesis unifies some recent results formulated for robotic hybrid position / force control under the modern framework of differential geometry and Lie groups.

No description available.

Robot control systems can be considered complex systems, the design of a controller involving the determination of the dynamic model for the system. This in itself can be a complicated task due to non-linearities, multiple axis (degrees of freedom) control and the constantly changing working environment. Problems arise when the theoretical model produced for such a system is not accurate. When developing a controller using conventional techniques a design scheme has to be produced, usually based on a model of the system. In addition kinematics equations must be derived to take into account the physical boundaries of the system. The work outlined in this thesis utilises fuzzy logic control to address these control issues. Fuzzy logic provides functional capability without the use of a system model and has characteristics suitable for capturing the approximate, vaiying values found in real world systems. Initial development of a single axis fuzzy logic control system was implemented on a Dainichi industrial five-axis robot, replacing the existing control and hardware systems with a new developmental system. The concept of fuzzy logic and its application to control highlights the potential advantages that fuzzy logic control (PLC) can provide when compared to the more conventional control methodologies. Additional new control hardware has been interfaced to an existing robot manipulator, making it possible to compare PLC and PIDVF (Proportional Integral Derivative Velocity FeedforwardlFeedback) controllers for single axis development. Average response time and overshoot for a given set point were compared for each system. The results proved that, using a basic PLC minimal overshoot and fast rise times could be achieved in comparison to the commercial PIDVF system. Further research concentrated on the development of the control software to provide multiple axis control for an industrial robot using a continuous path algorithm. The more from single axis to multiple axis control provided a much more complex control problem. A novel and innovative process for the fuzzy controller was implemented with up to three axes reaching the target point simultaneously. Control of the industrial robot was investigated using methods that were more suited to real time controL The most significant change was a reduction in the number of fuzzy rules when compared to single axis control. During robot control no adaptation of the rule base or membership functions was carried Out Ofl line; only system gain was modified in relation to link speed and joint error within predetermined design parameters. The fuzzy control system had to manage the effects of frictional and gravitational forces whilst compensating for the varying inertia components when each linkage is moving. Testing based on ISO 9283 for path accuracy and repeatability verified that real time control of three axes was achievable with values of 938tm and 864tm recorded for accuracy and repeatability respectively. The development of novel industrial robot real time multi-axis fuzzy controller has combined new control hardware with an efficient fuzzy engine addressing inverse kinematics, scaling and dynamic forces in order to provide a viable robot control system.

No description available.

No description available.

This programme of research was supported by NEI Parsons Ltd. who sought a robotic means of polishing mechanical components. A study of the problems associated with robot controlled surface processing is presented. From this evolved an approach consistent with the formalisation of the demands of workpiece manipulation which included the adoption of the Hybrid robot control scheme capable of simultaneous force and position control. A unique 3 axis planar experimental manipulator was designed which utilized combined parallel and serial drives. A force sensing wrist was used to measure contact force. A variant of the Hybrid control 'scheme was successfully implemented on a twin computer control system. A number of manipulator control programs are presented. The force control aspect is shown both experimentally and analytically to present control problems and the research has concentrated on this aspect. A general analysis of the dynamics of force control is given which shows force response to be dependent on a number' of important parameters including force sensor, environment and manipulator dynamics. The need for a robust or adaptable force controller is discussed. A series of force controlled manipulator experiments is described and the results discussed in the context of general analyses and specific single degree of freedom simulations. Improvements to manipulator force control are suggested and some were implemented. These are discussed together with their immediate application to the improvement of robot controlled surface processing. This work also lays important foundations for long term related research. In particular the new techniques for actively controlled assembly and force control under 'fast' operation.

the 18th World Congress The International Federation of Automatic Control, Milano (Italy), August 28 - September 2, 2011

Alors que les systèmes de reconnaissance gestuelle actuels privilégient souvent un usage intérieur, nous nous intéressons à la conception d'un système dont l'utilisation est possible en environnement extérieur et en mobilité. Notre objectif est le contrôle temps-réel d'un robot mobile dont l'usage est destiné aux fantassins débarqués. La contribution principale de cette thèse est le développement d'une chaîne de reconnaissance gestuelle temps réel, qui peut être entraînée en quelques minutes avec: un faible nombre d'exemples ("small data"); des gestes choisis par l'utilisateur; une résilience aux gestes mal réalisés; ainsi qu'une faible empreinte CPU. Ceci est possible grâce à deux innovations clés: d'une part, une technique pour calculer des distances entre séries temporelles en flux, basée sur DTW; d'autre part, une rétro-analyse efficace du flux d'apprentissage afin de déterminer les hyperparamètres du modèle sans intervention de l'utilisateur. D'autre part, nous avons construit notre propre gant de données et nous l'utilisons pour confirmer expérimentalement que la solution de reconnaissance gestuelle permet le contrôle temps réel d'un robot en mobilité. Enfin, nous montrons la flexibilité de notre technique en ce sens qu'elle permet de contrôler non seulement des robots, mais aussi des systèmes de natures différentes. / Although gesture recognition has been studied for several decades, much research stays in the realm of indoors laboratory experiments. In this thesis, we address the problem of designing a truly usable, real- world gesture recognition system, focusing mainly on the real-time control of an outdoors robot for use by military soldiers. The main contribution of this thesis is the development of a real-time gesture recognition pipeline, which can be taught in a few minutes with: very sparse input ("small data"); freely user-invented gestures; resilience to user mistakes during training; and low computation requirements. This is achieved thanks to two key innovations: first, a stream-enabled, DTW-inspired technique to compute distances between time series; and second, an efficient stream history analysis procedure to automatically determine model hyperparameters without user intervention. Additionally, a custom, hardened data glove was built and used to demonstrate successful gesture recognition and real-time robot control. We finally show this work's flexibility by furthermore using it beyond robot control to drive other kinds of controllable systems.