Observer design for a nonlinear diffusion system based on the Kirchhoff transformation

International audienceThis paper deals with the state estimation for a nonlinear diffusion system. An observer that reconstructs the whole state, from the available measurements, is proposed based on an equivalent linear diffusion model obtained using the Kirchhoff tangent transformation. This bijective mapping allows to apply the available and powerful state estimation theory of linear distributed parameter systems and simplifies the observer design. Hence, an observer can be designed for the obtained equivalent linear diffusion system and by using the Kirchhoff transformation, the whole state of the original nonlinear diffusion system is recovered. The observability analysis of the nonlinear diffusion system and the convergence of the proposed observer are also investigated based on the equivalent linear diffusion system. The effectiveness of the proposed observer is shown, through numerical simulation runs, in the case of a heated steel rod by considering both an uniformly distributed and a punctual boundary sensing

Secure Digital Communication based on Hybrid Dynamical Systems

International audienceIn this work, a transmission scheme based on the hybrid and chaotic dynamics for private communications is proposed. The transmitter is composed of a continuoustime system and a discrete-time system in which the message is inserted by inclusion. The states of the continuous system are also included, after sampling, in the discrete system. The receiver is composed of a discrete-time delay observer and a continuous-time observer. The principle of the proposed hybrid method is to show that the reconstruction of discrete states of the receiver and the message passes at first by a synchronization of the two continuous-time chaotic systems. This new strategy makes the system of transmission robust, in particular against an attack known plaintext. Simulation results are presented to highlight the performances of the proposed method

Sensorless Fault Tolerant Control Based On Backstepping Strategy For Induction Motors

International audienceIn this paper, a fault tolerant control for induction motors based on backstepping strategy is designed. The proposed approach permits to compensate both the rotor resistance variations and the load torque disturbance. Moreover, to avoid the use of speed and ux sensors, a second order sliding mode observer is used to estimate the ux and the speed. The used observer converges in a nite time and permits to give a good estimate of ux and speed even in presence of rotor resistance variations and load torque disturbance. The simulation results show the e ciency of the proposed control scheme

Backstepping Fault Tolerant Control Based on Second Order Sliding Mode Observer : Application to Induction Motors

International audienceIn this paper, a fault tolerant control for induction motors based on backstepping strategy is designed. The proposed approach permits to compensate both the rotor resistance variations and the load torque disturbance. Moreover, to avoid the use of speed and flux sensors, a second order sliding mode observer is used to estimate the flux and the speed. The used observer converges in a finite time and permits to give a good estimate of flux and speed even in presence of rotor resistance variations and load torque disturbance. The stability of the closed loop system (controller + observer) is shown in two steps. First, the boundedness of the trajectories before the convergence of the observer is proved. Second, the trajectories convergence is proved after the convergence of the observer. The simulation results show the efficiency of the proposed control scheme

Model reduction of homogeneous-in-the-state bilinear systems with input constraints

Accepted versio

Prescribed-Time Sliding Mode Observer for Nonlinear Triangular Systems

International audienc

Controllability and observability of linear discrete-time fractionalorder systems

In this paper we extend some basic results on the controllability and observability of linear discrete-time fractional-order systems. For both of these fundamental structural properties we establish some new concepts inherent to fractional-order systems and we develop new analytical methods for checking these properties. Numerical examples are presented to illustrate the theoretical results