Control Algorithms for a Sailboat Robot with a Sea Experiment

International audienceA sailboat robot is a highly nonlinear system but which control is relatively easy, however. Indeed, its mechanical design is the result of an evolution over thousands of years. This paper focuses on a control strategy which remains simple, with few parameters to adjust and meaningful with respect to the intuition. A test on the sailboat robot called Vaimos is presented to illustrate the performance of the regulator with a sea experiment. Moreover, the HardWare In the Loop (HWIL) methodology has been used for the validation of the embedded system. Last point is that this HWIL simulation compared to the real experiment is also a confirmation that the dynamic model used for control is correct

Interval analysis and convex optimization to solve a robust constraint feasibility problem

International audienceThis paper deals with the Robust Constraint Feasibility (RCF) problem which aims finding all θ such that there exists a vector x satisfying the constraint f(x, θ) < 0. An interval based algorithm will answer the question but with a crippling computational complexity which is exponential with respect to the dimension of the vector (x, θ). If the constraint function is assumed to be convex in x when θ is fixed, the paper shows that the complexity of the problem becomes polynomial with respect to the dimension of vector x and exponential with respect to the dimension of vector θ. Another contribution of the paper is to provide an algorithm which combines convex optimization and interval analysis to solve the problem with the reduced complexity. As an illustration, a simple numerical example is given

Global Optimization of H ∞ problems: Application to robust control synthesis under structural constraints

International audienceIn this paper, a new technique to compute a synthesis structured Robust Control Law is developed. This technique is based on global optimization methods using a Branch-and-Bound algorithm. The original problem is reformulated as a min/max problem with non-convex constraint. Our approach uses interval arithmetic to compute bounds and accelerate the convergence

Sea glider guidance around a circle using distance measurements to a drifting acoustic source

International audienceThis paper describes a simple yet robust sea glider guidance method in a constellation of Lagrangian drifters under the polar ice cap. The glider has to perform oceanographic measurements, mainly conductivity, temperature and depth, in the area enclosed by the drifters and can not rely on GNSS (Global Navigation Satellite System) positionning data as the polar ice cap makes it impossible to surface. The originality of the presented method resides in 2 points. First, a very simple PID (Proportional, Integral and Derivative) controller based on a basic kinematic model is tuned. Second, the method does not use a localization algorithm to estimate state space model data but interval analysis methods are performed to bound the errors in range to the transponder and its derivative. Moreover, only one acoustic beacon is used. Validation is then performed through simulations

Commande Robuste et Contraintes d'Optimisation

This thesis presents an overview of my research activities carried out since my PhD in 2001. In the first section, description of the projects, my different contributions to robust control applied to the spatial field and underwater robotics, are highlighted. My research project for the coming years is then presented; I propose an original and efficient methodology to compute simple control laws by combining \textit{robust control} and \textit{global optimization}. The second part of this thesis is dedicated to the scientific aspects that will help clarify the proposed research project. As a starting point, Youla parametrization is presented as a tool to \textit{render convex} the control problem, and the subsequent work is used as a foundation to establish specifications based on the constraints related to optimization. This theme has served as a driving thread in illustrating how industrial requirements could lead to a control problem. Parallel to this, the question also arose as to the practical realization of results from these methodologies, that is, how they might be implemented in an embedded system. Ariane 5 launcher control is taken as an example for research on the structured control and validation.Ce mémoire présente un panorama des activités de recherche menées depuis ma thèse de doctorat en 2001. Dans une première partie, à travers la description des projets, sont mises en avant les différentes contributions à la commande robuste appliquée au monde spatial et au monde de la robotique sous-marine. On montre alors comment s'est construit le projet de recherche proposé pour les années à venir. Il s'agit de proposer une méthodologie originale et efficace pour régler des lois de commande simple à implémenter en combinant \textit{commande robuste} et \textit{optimisation globale}. La seconde partie de ce mémoire est consacrée à quelques aspects scientifiques qui aident à comprendre le projet de recherche proposé. On y trouve comme point de départ la paramétrisation de Youla en tant qu'outil pour \textit{convexifier} le problème de commande et les travaux qui en ont découlés pour traduire un cahier des charges en terme de contrainte dans un problème d'optimisation. Cette thématique a été un fil conducteur important pour faire le lien avec la demande industrielle de savoir comment les exigences étaient traduites dans le problème de commande. En parallèle, s'est posée la question de la réalisation pratique des résultats issues de ces méthodologies, c'est-à-dire leur implémentation sur un système embarqué. On prendra comme exemple les activités de recherche sur la structuration de correcteur et leur qualification pour les lois de pilotage des lanceurs Ariane 5

Sliding mode reference conditioning for path following applied to an AUV

This work presents a dynamic model for an autonomous underwater vehicle (AUV), a validation of this model together with the simulator obtained from its application and an implementation of sliding mode reference conditioning (SMRC). This last technique is proposed in order to follow a path at maximum speed with bounded errors in a dynamical framework, taking care of the saturation in systems actuators, resulting in an improvement of the path tracking time.Fil: Rosendo, Juan Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; ArgentinaFil: Clement, Benoit. Centre National de la Recherche Scientifique; Francia. Laboratoire Des Sciences Et Techniques de L'information, de la Communication Et de la Connaissance; FranciaFil: Garelli, Fabricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales. Universidad Nacional de La Plata. Instituto de Investigaciones en Electrónica, Control y Procesamiento de Señales; Argentin

The disabled set sail

International audienceSailing is not an activity that can easily be done with a handicap. Sailors typically need mobility to steer a boat. An Arduino-compatible CAN architecture for sailing applications is set to change that

An Arduino compatible CAN Bus architecture for sailing applications

International audienceThis paper describes a Controller Area Network (CAN) Bus architecture based on Arduino compatible boards, to be used as an alternative communication system for robotic applications. This combines both, the robustness of CAN and the accessibility of Arduino software. The architecture is developed here to improve a Navigational Assistance System, which was initially created for disabled people. The system is composed of Arduino compatible boards, wired with various sensors and actuators, and communicating with an Human Machine Interface (HMI), directly accessible via a mobile phone or a tablet running on the open-source operating system Android. Information is transferred through the CAN bus architecture between multiple nodes (i.e. Arduino compatible boards) and the implementation of a CAN bootloader allows the reconfiguration of the nodes directly through the bus. The aim is to create a generic system able to work in various kinds of situations, adaptable to all kinds of users, including persons with all sorts of disabilities. This work will result in a demonstrator on a Miniji for the WRSC 2013 and an entirely joystick controlled boat for single handed sailing

FPGA Implementation of a Parameterized Fourier Synthesizer

International audienceField-Programmable Gate Array (FPGA) offers advantages for many applications, particularly where missions are complex and time performance is critical. For small-production digital acoustic synthesizers, FPGA can achieve the above-mentioned tighter system requirements with low total system costs on single chip. In this manuscript, a real-time acoustic synthesizer is implemented using Fourier series algorithm on Altera's Cyclone II FPGA chip. This work emphasizes systematic designs and parallel computations. The proposed system includes a flexible processor and a parallel parameterized acoustic module. On one hand, the Nios II embedded processor, which is relatively low-speed component, is used to generate commands and configure high-speed acoustic module parameters. On the other hand, acoustic module which should require high-speed components contains 4 parallel architectures to gain high-speed simultaneous calculus of 4 independent digital timbres. Every timbre is equivalent to 16 parallel high-precision harmonic channels with 0.3 % frequency error. Experimental results corroborate the fact that a single FPGA chip can achieve complex missions and attain real-time performances

Système d'assistance à la navigation handivoile

International audienceCe projet, fruit d'une collaboration entre l'ENSTA-Bretagne et l'entreprise Splashelec vise à développer une Interface Homme-Machine (IHM) qui facilite la navigation par le biais de capteurs et d'un boîtier de commandes embarqué sur le bateau. Il se concrétise par la création d'une interface graphique directement accessible via un téléphone mobile pour pallier le manque de mobilité du navigateur