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Theses

Contribution à la synthèse de commandes référencées vision 2D multi-critères

Bo Gao 1
1 LAAS-RIA
LAAS - Laboratoire d'analyse et d'architecture des systèmes
Abstract : This thesis presents the design of multicriteria 2D image-based controllers to position a 3-DOF camera with respect to a fixed or mobile target. The camera is supposed to be supported by a robotic system which allows any horizontal translations and rotations about the vertical axis. The frequency and the quality of information delivered by the CCD cameras which equip today the robots make indeed possible the direct alimentation of the loops of control by visual measurements of the environment. The model considered is defined in the framework of the task function approach and is based on the concept of screw of interaction which allows linking up the movement of the camera with the variation of the visual indices. The objective of this work is to propose control laws to stabilize the camera on the basis of two-dimensional information resulting from the image, despite the uncertainty on the depth of the target points, the constraints of visibility and the limits on the camera velocity and acceleration. The proposed method implements advanced control techniques. It is based on the satisfaction of a modified sector condition to take into account the saturation of acceleration and the description of the closed-loop system via a polytopic model of uncertainties. This approach allows formulating constructive conditions which can be expressed in the form of Matrix Linear Inequalities (LMIs). From this formulation, some LMI-based convex optimization schemes are considered for computing the feedback gain that leads to the maximization of the size of the associated region of stability. The technique, initially applied to the positioning problem of the camera with respect to a fixed target, is then extended to track a moving target by regarding the unknown target velocity as a disturbance limited in energy. Then, the interest of the approach for designing control strategies, to link dynamically a sequence of sensor-based tasks for the problem of navigation of a mobile robot, is shown. Several examples of sequences of tasks are considered and simulated on the basis of a model of car-like robot equipped with the sensors of proximity and supporting a camera mounted on a directional pan-platform in azimuth.
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https://tel.archives-ouvertes.fr/tel-00119789
Contributor : Emilie Marchand <>
Submitted on : Tuesday, December 12, 2006 - 10:51:37 AM
Last modification on : Friday, January 10, 2020 - 9:10:13 PM
Long-term archiving on: : Tuesday, April 6, 2010 - 7:59:51 PM

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  • HAL Id : tel-00119789, version 1

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Bo Gao. Contribution à la synthèse de commandes référencées vision 2D multi-critères. Mathématiques [math]. Université Paul Sabatier - Toulouse III, 2006. Français. ⟨tel-00119789⟩

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