17179

14/05/2019

A.SEURET, C.PRIEUR, S.TARBOURIECH, L.ZACCARIAN

MAC, GIPSA-Lab

Revue Scientifique : IEEE Transactions on Automatic Control, Vol.64, N°5, pp.2061-2068, Mai 2019 , N° 17179

Lien : https://hal.laas.fr/hal-01526331

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We first propose a nonsmooth hybrid invariance principle with relaxed conditions stemming from the fact that flowing solutions evolve only in the tangent cone, and complete jumping solutions cannot jump ouside the jump and flow sets. We then show an application consisting in the design of event-triggered rules to stabilize a class of uncertain linear control systems. The event-triggering rule depends only on local information, that is it uses only the output signals available to the controller. The approach proposed combines a hybrid framework to describe the closed-loop system with looped functionals based techniques. The proposed design conditions are formulated in terms of linear matrix inequalities (LMIs) ensuring global robust asymptotic stability of the closed-loop system. A tunable parameter is also available to guarantee an adjustable dwell-time property of the solutions. The effectiveness of the approach is evaluated through an example borrowed from the literature.

18218

01/05/2019

D.HENRION, M.KRUZIK, T.WEISSER

MAC, CzechTech. Univ.

Revue Scientifique : Automatica, Vol.103, pp.159-165, Mai 2019 , N° 18218

Lien : https://hal.archives-ouvertes.fr/hal-01802883

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Optimal control problems with oscillations (chattering controls) and concentrations (impulsive controls) can have integral performance criteria such that concentration of the control signal occurs at a discontinuity of the state signal. Techniques from functional analysis (anisotropic parametrized measures) are applied to give a precise meaning of the integral cost and to allow for the sound application of numerical methods. We show how this can be combined with the Lasserre hierarchy of semidefinite programming relaxations

18029

01/05/2019

C.GAZZINO, D.ARZELIER, L.CERRI, D.LOSA, C.LOUEMBET, C.PITTET

MAC, ROC, CNES, Thalès Alenia Space

Revue Scientifique : Acta Astronautica, Vol.158, pp.12-22, Mai 2019 , N° 18029

Lien : https://hal.laas.fr/hal-01696455

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In this paper, a control scheme is elaborated in order to perform the station keeping of a geostationary satellite equipped with electric propulsion while minimizing the fuel consumption. The use of electric thrusters imposes to take into account some additional non linear and operational constraints that make the overall station keeping optimal control problem difficult to solve directly. That is why the station keeping problem is decomposed in three successive control problems. The first one consists in solving a classical optimal control problem with an indirect method initialized by a direct method without enforcing the thrusters operational constraints. Starting from this non feasible solution for the genuine problem, the thrusters operating constraints are incorporated in the second problem, whose solution produces a feasible but non optimal control profile via two different ways. Finally, the third optimizes the commutation times thanks to a method borrowed to the switched systems theory. Simulation results on a realistic example validate the benefit of this particular control scheme in the reduction of the fuel consumption for the geostationary station keeping problem.

14820

25/03/2019

A.SEURET, H.OZBAY, C.BONNET

MAC, Bilkent University, INRIA Paris

Ouvrage (éditeur) : Low-Complexity Controllers for Time-Delay Systems, N°ISBN 978-3-319-05575-6, Mars 2019 , N° 14820

Lien : https://hal.archives-ouvertes.fr/hal-02057344

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This volume in the newly established series Advances in Delays and Dynamics (ADD@S) provides a collection of recent results on the design and analysis of Low Complexity Controllers for Time Delay Systems. A widely used indirect method to obtain low order controllers for time delay systems is to design a controller for the reduced order model of the plant. In the dual indirect approach, an infinite dimensional controller is designed first for the original plant model; then, the controller is approximated by keeping track of the degradation in performance and stability robustness measures. The present volume includes new techniques used at different stages of the indirect approach. It also includes new direct design methods for fixed structure and low order controllers. On the other hand, what is meant by low complexity controller is not necessarily low order controller. For example, Smith predictor or similar type of controllers include a copy of the plant internally in the controller, so they are technically infinite dimensional. However, they have very nice numerical properties from the point of reliable implementation. Therefore, such predictor-based controllers are considered as low complexity. This book includes new predictor-based design techniques, with several application examples.

18024

18/02/2019

C.GAZZINO, D.ARZELIER, C.LOUEMBET

MAC, ROC

Revue Scientifique : Journal of Guidance, Control, and Dynamics, Février 2019, doi10.2514/1.G003644 , N° 18024

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The problem of the computation of correction maneuvers for the fuel-optimal long-term station-keeping within a predefined longitude and latitude window of a geostationary satellite equipped with electric propulsion is investigated. The use of electric thrusters imposes some additional operational constraints on actuation that can be reformulated as logical constraints on the control function. The resulting fuel-optimal station-keeping problem is therefore transformed into a mixed linear integer programming problem. The long-term horizon of station-keeping is divided in shorter control cycles synchronized with the cycles of orbit determination, and the long-term station-keeping problem amounts to solve a sequence of similar mixed linear integer programming problems with different initial conditions. Two different terminal constraints on geographical positions and/or linear velocities are added to the formulation of the mixed linear integer programming problems to ease the feasibility of the whole sequence of successive resolutions. Nonlinear perturbed simulations of the computed control strategies show their efficiency on a long-term station-keeping problem lasting one year.

18402

01/02/2019

P.FRASCA, S.TARBOURIECH, L.ZACCARIAN

GIPSA-Lab, MAC

Revue Scientifique : Automatica, Vol.100, pp.153-161, Février 2019 , N° 18402

Lien : https://hal.archives-ouvertes.fr/hal-01940187

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This paper is a first attempt at using tools from the theory of hybrid systems to study opinion dynamics on networks with opinion-dependent connectivity. According to the hybrid framework, our dynamics are represented by the combination of continuous flow dynamics and discrete jump dynamics. The flow embodies the attractive forces between the agents and is defined by an ordinary differential equation whose right-hand side is a Laplacian, whereas the jumps describe the activation or deactivation of the pairwise interactions between agents. We first reformulate the classical Hegselmann–Krause model in this framework and then define a novel interaction model, which has the property of being scale-invariant. We study the stability and convergence properties of both models by a Lyapunov analysis, showing convergence and clusterization of opinions.

16375

01/01/2019

D.HENRION, S.NALDI, M.SAFEY EL DIN

MAC, LIP6-CNRS, TU Dortmund

Revue Scientifique : Optimization Methods and Software, Vol.34, N°1, Janvier 2019 , N° 16375

Lien : https://hal.laas.fr/hal-01393022

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This document briefly describes our freely distributed Maple library spectra, for Semidefinite Programming solved Exactly with Computational Tools of Real Algebra. It solves linear matrix inequalities in exact arithmetic and it is targeted to small-size, possibly degenerate problems for which symbolic infeasibility or feasibility certificates are required.

18387

01/01/2019

A.TANWANI, S.TRENN

MAC, University of Groningen

Revue Scientifique : Automatica, Vol.99, pp.289-300, Janvier 2019 , N° 18387

Lien : https://hal.laas.fr/hal-01933110

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This paper studies detectability for switched linear differential–algebraic equations (DAEs) and its application to the synthesis of observers, which generate asymptotically converging state estimates. Equating detectability to asymptotic stability of zero-output-constrained state trajectories, and building on our work on interval-wise observability, we propose the notion of interval-wise detectability: If the output of the system is constrained to be identically zero over an interval, then the norm of the corresponding state trajectories scales down by a certain factor at the end of that interval. Conditions are provided under which the interval-wise detectability leads to asymptotic stability of zero-output-constrained state trajectories. An application is demonstrated in designing state estimators. Decomposing the state into observable and unobservable components, we show that if the observable component of the system is reset appropriately and persistently, then the estimation error converges to zero asymptotically under the interval-wise detectability assumption.

18383

01/01/2019

A.RODRIGUES DEL NOZAL, P.MILLAN GATA, L.ORIHUELA, A.SEURET, L.ZACCARIAN

Loyola Andalucía, MAC

Revue Scientifique : Automatica, Vol.99, pp.213-220, Janvier 2019 , N° 18383

Lien : https://hal.laas.fr/hal-01920417

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This paper deals with the problem of distributedly estimating the state of an LTI plant through an interconnected network of agents. The proposed approach results in an observer structure that incorporates consensus among the agents and that can be distributedly designed, achieving a robust solution with a good estimation performance. The developed solution is based on an iterative decomposition of the plant in the local observable staircase forms. The proposed observer has several positive features compared to recent results in the literature, which include milder assumptions on the network connectivity and the ability to set the convergence rate.

18362

01/01/2019

Q.L.HAN, X.M.ZHANG, A.SEURET, F.GOUAISBAUT, Y.HE

Swinburne, MAC

Revue Scientifique : IET Control Theory & Applications, Vol.13, N°1, 15p., Janvier 2019, doi 10.1049/iet-cta.2018.5188 , N° 18362

Lien : https://hal.laas.fr/hal-01920425

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This paper provides an overview and in-depth analysis of rec ent advances in stability of linear systems with time-varyi ng delays. First, recent developments of a delay convex analys is approach, a reciprocally convex approach and the constru ction of Lyapunov-Krasovskii functionals are reviewed insightful ly. Second, in-depth analysis of the Bessel-Legendre inequ ality and some affine integral inequalities is made, and recent stability r esults are also summarized, including stability criteria f or three cases of a time-varying delay, where information on the bounds of the t ime-varying delay and its derivative is totally known, part ly known and completely unknown, respectively. Third, a number of stabi lity criteria are developed for the above three cases of the t ime-varying delay by employing canonical Bessel-Legendre inequalitie s, together with augmented Lyapunov-Krasovskii functiona ls. It is shown through numerical examples that these stability criteria o utperform some existing results. Finally, several challen ging issues are pointed out to direct the near future research.

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