Salim Chaib

Invertibility of switched nonlinear systems. Application to missile faults reconstruction.

This paper presents a new approach for the invertibility of a class of switched systems. These systems are affine in the unknown input. In our approach, the inverse dynamic is given by means of a projection which decompose the state space into two transverse foliations: one is tangent to the unknown inputs and the other is transverse. A missile fault reconstruction is investigated in this paper.

Observer design for linear switched systems : A common Lyapunov function approach

In this paper, we give sufficient conditions for the stability of a class of switched systems. Based on the symmetric part of the state space matrix and on LaSalles invariance principle, to ensure the asymptotic stability of switched linear systems, under a special class of switching signals. The proposed stability results are used to design an observer of switched linear systems for which the discrete state is available. Examples are given to highlight our propositions.

Dynamic Controller of Switched Linear Systems : a Common Lyapunov Function Approach

This paper is devoted to the problem of design a dynamic controller of switched linear systems. In the first part of this paper, we give some remarks about the influences of switching signal on the asymptotic stability of switched systems. We give a practical example to generate a large class of switching signals. The second part is devoted to the switched dynamic controller design, based on a common Lyapunov function approach. A sufficient condition is formulated as an LMI problem for the switched controller design under arbitrary switching. A stabilizing switched controller with regional pole placements is also formulated as a convex problem, an LMI approach is used to derive the switched dynamic controller with performance limitations

Projector-based switching signal reconstruction and observer for switched systems

This paper is devoted to the problem of switching signal reconstruction. In the first part of this paper, we give a new approach for the invertibility of switched nonlinear systems, and we give the algorithm of switching signal reconstruction. In the second part, we give some remarks about observer design. Some sufficient conditions are formulated as an LMI problem for the switched observer design.

A GENERALIZED NORMAL FORM AND NONLINEAR OUTPUTS FOR A CASCADE OBSERVER

Abstract This paper gives a generalized observer for a class of cascade dynamical systems. Moreover, we give sufficient conditions which guarantee the existence of a diffeomorphism in order to transform a nonlinear system into a canonical cascade normal form.

A foliation for unknown inputs reconstruction

Abstract This paper deals with a new method to compute the left inverse for a class of dynamical systems. This method is based on a projection which decompose the state space into two transverse foliations: one is tangent to the unknown inputs and the other is transverse. Contrary to the traditional methods, our method enables us to write the inverse dynamic system under consideration. Within this work we highlight our propositions by examples.

Hysteresis switched observer with regional pole placements for general manipulation systems

In this paper, we focus on the problem of a observer design for a manipulation system. The mechanical compliance introduced by the cooperation between the manipulators and their interactions with load is complex and nonlinear which makes the observer design very difficult. The last motivates us to develop a new approach to design a multi models-based observer that we will call hysteresis switched observer. The proposed hysteresis switched observer is based on a piecewise linear approximation of the dynamic model. The robust design of the observers composing the hysteresis switched one and the hysteresis behavior of the switching logic ensure the asymptotic stability of the error of the observation with a smooth dynamics

Sensors optimization-based control of two planar robots in lifting

In this paper, we focus on one of the central problem of observers design and control of general manipulation systems. The mechanical compliance introduced by the cooperation between the manipulators and their load interactions complex. First, the control must be designed in this case in order to realize the object trajectory and/or external forces tracking. But, the controller action must respect and not violate at each moment the kinematic constraint of the manipulation system. Seconde and more importantly, the augmented manipulation system (the closed chain : manipulators-object) is nonlinear and complex system, then the observer design is very difficult, which motivate us to develop a new approach to design a multi models-based observer which we call hysteresis hybrid observer.

Control for induction motor fed by five level inverter with sliding mode observer

In this paper, a technique of robust control for an induction motor is presented. This motor is fed by five-level inverter controlled by the triangulo-sinusoidal strategy with four bipolar carriers. The control algorithm uses robust regulators calculated by the Hinfin loop shaping approach associated with indirect field oriented control. The sliding mode observer is used to observe the rotor flux in the induction motor. The simulation results show that the controllers stabilize the system and reject the disturbances when the system is subjected to uncertainties, which theirs norms are lower than the maximum stability margin

Algebraic and geometrical conditions for the observability of the discrete state of a class of hybrid systems

In this paper we deal with the observability of piecewise-affine hybrid systems. Our aim is to give the sufficient conditions to observe the discrete and continuous states, in terms of algebraic and geometrical conditions. First, we will give the algebraic conditions for discrete state observability based on the switch function reconstruction for linear hybrid systems. Secondly, we will give a geometrical condition based on a transversality concept for nonlinear hybrid systems