H − /H ∞ robust fault detection observer for uncertain switched systems

International audienceThis paper addresses a method for robust fault detection (RFD) by maximizing the fault to residual sensitivity. It uses the newly developed H− index properties and minimizing the well known H∞ norm for worst case uncertainties and disturbance attenuation. These objectives are coupled to a transient response specification expressed by eigen region assignment formulation. The 3-objective robust fault detection problem is formulated as LMI feasibility problem in which a cost function is minimized subject to LMI constraints

Generalized Luenberger observers for fault detection in switched systems using H- index

International audience—In this paper, a linear matrix inequality (LMI) technique for the fault detection and state estimation of switched discrete systems is proposed. This approach is employed to generate generalized Luenberger minimal order observers giving best state estimation and sensitive fault detection. It consists on using H− index design. Sufficient conditions of global convergence of observers are proposed using switched Lyapunov functions. Numerical example is given to illustrate this method

PI robust fault detection observer for a class of uncertain switched systems using LMIs

International audienceThis paper addresses a method for robust fault detection and estimation by minimizing the disturbance and uncertainties to residual sensitivity. It consists in the design of proportional integral observer while minimizing the well known H ∞ norm for worst case uncertainties and disturbance attenuation, and combining a transient response specification. This multi-objective problem is formulated as linear matrix inequalities (LMI) feasibility problem in which a cost function is minimized subject to LMI constraints. This approach is employed to generate a set of robust observers for uncertain switched systems

Fault detection for LPV systems: Loop shaping H− approach

International audienceThis paper addresses a method for fault detection (FD) in linear parameters varying (LPV) systems by maximizing the fault to residual sensitivity. It uses the newly developed H − index properties and minimizing the well known H ∞ norm for worst case uncertainties and disturbance attenuation. A loop shaping approach for the H − FD problem is proposed. The multi-objectives problem is formulated as Linear Matrix Inequalities (LMI) problem for polytopic systems. An application on lateral vehicle dynamics is given as an illustrative example for this approach

A Reduced Model of Three Ways Catalyst Converter and Stored Oxygen Rate Estimation Using Switched Observer

International audiencePollutant emissions limitations ruled by the latest standards force car manufacturers to improve after treatment systems. This improvement is achieved by new systems on one hand, and by more efficient control strategies, on the other. This paper describes a 0-D model of Three Ways Catalyst converter (TWC) which is able to reproduce the transient dynamics of the converter although simple. A switched observer of stored oxygen rate is derived from this reduced model, and its convergence is proved. An estimation of the oxygen capacity of TWC provides precious information for on-board diagnosis or monitoring purpose. First, a description of the TWC dynamics and its reduced model will be described, then a discrete time switched observer of the stored oxygen rate and the free site capacity estimation by least squares method are presented

Continuous-Time Switched H∞ Proportional-Integral observer: Application for sideslip and road bank angles estimation

International audience— In this work, a Continuous-Time Switched H ∞ Proportional-Integral (CTSH ∞ PI) observer is presented. The estimation method is based on a proportional-integral observer introduced by [13], [11], [12]. The estimation method is used to estimate simultaneously the state variables and unknown inputs of switched systems. A design method is established using a common Lyapunov function and H ∞ norm. Its stability and global convergence conditions are proved and expressed in term of LMIs. All conditions are established under given switching signals. The estimation method is applied in vehicle dynamics to estimate simultaneously the vehicle sideslip angle and road bank angle. Moreover, the switching signal is deduced from measured premise variables. Simulation tests with experimental data are included to demonstrate the advantage of this method

Simple Tracking Output Feedback H ∞ Control for Switched Linear Systems: Lateral Vehicle Control Application

International audienceIn this paper, the problem of the switched H ∞ tracking output feedback control problem is studied. The control design problem is addressed in the context of discrete-time switched linear systems. Then, the design of continuous-time case becomes trivial. Linear Matrix Inequality (LMI) and Linear Matrix Equality (LME) representations are used to express all sufficient conditions to solve the control problem. Some transformations leading to sufficient conditions for the control problem are also used. All conditions are established for any switching using a switched Lyapunov function and a common Lyapunov function. The effectiveness of the proposed control approach is shown through a steering vehicle control implementation. Interesting simulation results are obtained using real data acquired by an instrumented car

Driver torque estimation in Electric Power Steering system using an H ∞ /H 2 Proportional Integral Observer

International audienceThis paper deals with the design of a Proportional Integral (PI) observer to estimate the driver torque in an Electric Power Steering (EPS) system. The PI observer is obtained by solving a multi-objective optimization problem: it should both be barely sensitive to road disturbances and sensor noise, and converge swiftly. The performance of the proposed observer is illustrated by simulation results using experimental data

Reduced Model of Engine Air Path System Using a LPV Approach

International audienceThis paper describes a reduced model of an engine air path composed of a supercharger with throttle valve. This "industry-oriented" model is intended for control purposes. The air-path system dynamics are governed by the Saint-Venant equations, difficult to handle in control synthesis due to nonlinear properties (states -control inputs coupling, nonlinear functions). To take account the intrinsic nonlinear properties of the air-path model in control purpose, a Linear Parameter Varing (LPV) state space representation is proposed. The model is simplified considering that slow dynamics are constant, allowing to reduce the number of time varying parameters, and, therefore, the calibration time for control synthesis. The reduced LPV model is compared with the nonlinear one, and validated on air path benchmark data, showing that the model is representative enough of the system, and suitable for advanced and robust controller synthesis

H ∞ Feedback Control for Switched Linear Systems: Application to an Engine Air Path System

International audienceThis paper presents the results of an engine air-path Hinf state feedback switched linear controller. The main advantage of this approach is that controller gains are calculated offine, with the robust specifications allowing fast calculation and is cost-effective in calculationand resources. The air-path system dynamics are governed by the Saint-Venant equations, diffcult to handle in control synthesis due to its nonlinear properties (states - control inputs coupling, nonlinear functions). To employ advanced control techniques, a switched linear state space representationis proposed. The model is simplified considering that slow dynamics are quite constant. The proposed approach provides a robust state feedback control toward perturbations (model error, unmodeled dynamics...) by considering these disturbances as unknown inputs