Damien Koenig
Centre national de la recherche scientifique
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Featured researches published by Damien Koenig.
Vehicle System Dynamics | 2002
Saïd Mammar; Damien Koenig
Summary This paper first analyses some stability aspects of vehicle lateral motion, then a coprime factors and linear fractional transformations (LFT) based feedforward and feedback H 8 control for vehicle handling improvement is presented. The control synthesis procedure uses a linear vehicle model which includes the yaw motion and disturbance input with speed and road adhesion variations. The synthesis procedure allows the separate processing of the driver reference signal and robust stabilization problem or disturbance rejection. The control action is applied as an additional steering angle, by combination of the driver input and feedback of the yaw rate. The synthesized controller is tested for different speeds and road conditions on a nonlinear model in both disturbance rejection and driver imposed yaw reference tracking maneuvers.
IEEE Transactions on Automatic Control | 2002
Damien Koenig; Saïd Mammar
This note presents simple methods to design full- and reduced- order proportional integral observer for unknown inputs (UI) descriptor systems. Sufficient conditions for the existence of the observer are given and proven. The observer is solvable by any pole placement algorithm, it achieves a posteriori robustness state and UI estimation versus to time varying parameters and bounded nonlinear UI. An illustrative example is included.
IEEE Transactions on Automatic Control | 2005
Damien Koenig
In this note, the problem of observer design for linear descriptor systems with faults and unknown inputs is considered. First, it is considered that the fault vector function f is s~ times piecewise continuously differentiable. If the s~th time derivative of f is null, then s~ integral actions are included into a Luenberger observer, which is designed such that it estimates simultaneously the state, the fault, and its finite derivatives face to unknown inputs. Second, when the fault is not time piecewise continuously differentiable but bounded (like actuator noise) or s~th time derivative of fault is not null but bounded too, a high gain observer is derived to attenuate the fault impact in estimation errors. The considered faults may be unbounded, may not be determinist, and faults and unknown inputs may affect the state dynamic and plant outputs. Sufficient conditions for the existence of such observer are given. Results are illustrated with a differential algebraic power system.
IEEE Transactions on Automatic Control | 2006
Damien Koenig
This paper treats the design problem of full-order observers for nonlinear descriptor systems with unknown input (UI). Depending on the available knowledge on the UI dynamics, two cases are considered. First, a UI proportional observer (UIPO) is proposed when the spectral domain of the UI is unknown. Second, a PIO is proposed when the spectral domain of the UI is in the low frequency range. Sufficient conditions for the existence and stability of such observers are given and proved. Based on the linear matrix inequality (LMI) approach, an algorithm is presented to compute the observer gain matrix that achieves the asymptotic stability objective. An example is included to illustrate the method.
IEEE Transactions on Automatic Control | 2004
Benoît Marx; Damien Koenig; Didier Georges
A new architecture for fault tolerant controllers is proposed for the generic class of descriptor systems. It is based on coprime factorization of nonproper systems and on the Youla parameterization of stabilizing controllers. Noticing that the Youla controllers include a so called residual signal, fault tolerant control is achieved. Nominal control and robust fault tolerance are addressed separately. Moreover, fault tolerant control can be improved with a scheme integrating fault diagnosis. The design of the diagnosis and fault tolerant control filters reduce to a standard H/sub /spl infin//-control problem of usual state-space system.
american control conference | 2001
Damien Koenig; S. Mammar
The problem of fault detection in nonlinear systems is considered. Our goal is to extend the unknown inputs observer approach to nonlinear systems. The approach consists of two stages. At the first stage, a change of coordinates is found that decoupled the nonlinear system into two subsystems: one is independent of the unknown inputs and the other with the states is expressed as linear combinations of the outputs and the states of the first subsystem. At the second stage, a nonlinear observer is designed for the former. The use of such observer for robust fault detection purposes is then discussed, and finally illustrated by a numerical example.
conference on decision and control | 2003
Benoît Marx; Damien Koenig; Didier Georges
This paper presents the design of a proportional-integral observer for descriptor systems subject to faults and unknown inputs. The observer is synthesized to minimize the influence of unknown inputs on the estimation. Weighting transfer is introduced to shape the sensitivity of the estimation to the unknown inputs. Particular attention is paid to fault diagnosis objective. The proposed method is based on the solution of LMI and guarantees the estimation of the states and faults to be robust face to unknown inputs. A numerical example is included.
conference on decision and control | 2005
Damien Koenig; N. Bedjaoui; Xavier Litrico
This paper deals with the problem of full-order observers design for linear continuous delayed state and inputs systems with unknown input (UI) and time-varying delays. A method to design an Unknown Input Observer (UIO) for such systems is proposed based on a delay-dependent stability conditions of the state estimation error system. A Fault Detection and Isolation (FDI) scheme using a bank of such UIO, is also presented and tested on a (FDI) problem related to irrigation canals.
IFAC Proceedings Volumes | 2005
Denis Jacquet; Carlos Canudas de Wit; Damien Koenig
Abstract This paper treats the problem of optimizing a coordinated ramp metering strategy based on a distributed macroscopic traffic model. The Lighthill, Whitham and Richards (LWR) model is extended to include on/off-ramps with on-ramp flow saturations and an optimal control formulation is proposed. Using optimization techniques in Banach spaces, a solution is shown to exist and the necessary optimality system is stated using formal adjoint calculus. An iterative descent algorithm and numerical methods for gradient evaluations are proposed to compute the optimal strategy with reasonable effort. The effectiveness of the approach is illustrated through a study case with field data.
Automatica | 2016
Damien Koenig; Benoît Marx; Sébastien Varrier
In this paper, the problems of state and fault estimation are addressed for a class of switched descriptor systems subject to Lipschitz nonlinearities and unknown inputs (UI). The UI appear both on the dynamic and on the measurement equations. Two problems are addressed by L 2 -gain minimization with the use of switched Lyapunov functions and formulated by LMI. First, a functional observer for switched Lipschitz nonlinear descriptor system is proposed for robust state estimation. Second, fault estimation is performed by filtering the output estimation error, as usually done in the residual generation framework. Moreover, frequency weighting functions can be used to shape the response to the fault and thus improve the estimation.