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Identification of a quasilinear parabolic equation from final data

Luis a. Fernández, Cecilia Pola (2001)

International Journal of Applied Mathematics and Computer Science

We study the identification of the nonlinearities A,(→)b and c appearing in the quasilinear parabolic equation y_t − div(A(y)∇y + (→)b(y)) + c(y) = u inΩ × (0,T), assuming that the solution of an associated boundary value problem is known at the terminal time, y(x,T), over a (probably small) subset of Ω, for each source term u. Our work can be divided into two parts. Firstly, the uniqueness of A,(→)b and c is proved under appropriate assumptions. Secondly, we consider a finite-dimensional optimization...

Improving the performance of semiglobal output controllers for nonlinear systems

Abdallah Benabdallah, Walid Hdidi (2017)

Kybernetika

For a large class of nonlinear control systems, the main drawback of a semiglobal stabilizing output feedback controllers ( 𝒰 R ) R > 0 with increasing regions of attraction ( Ω R ) R > 0 is that, when the region of attraction Ω R is large, the convergence of solutions of the closed-loop system to the origin becomes slow. To improve the performance of a semiglobal controller, we look for a new feedback control law that preserves the semiglobal stability of the nonlinear system under consideration and that is equal to some...

Indirect adaptive controller based on a self-structuring fuzzy system for nonlinear modeling and control

Ruiyun Qi, Mietek A. Brdys (2009)

International Journal of Applied Mathematics and Computer Science

In this paper, a unified nonlinear modeling and control scheme is presented. A self-structuring Takagi-Sugeno (T-S) fuzzy model is used to approximate the unknown nonlinear plant based on I/O data collected on-line. Both the structure and the parameters of the T-S fuzzy model are updated by an on-line clustering method and a recursive least squares estimation (RLSE) algorithm. The rules of the fuzzy model can be added, replaced or deleted on-line to allow a more flexible and compact model structure....

Infinite time regular synthesis

B. Piccoli (2010)

ESAIM: Control, Optimisation and Calculus of Variations

In this paper we provide a new sufficiency theorem for regular syntheses. The concept of regular synthesis is discussed in [12], where a sufficiency theorem for finite time syntheses is proved. There are interesting examples of optimal syntheses that are very regular, but whose trajectories have time domains not necessarily bounded. The regularity assumptions of the main theorem in [12] are verified by every piecewise smooth feedback control generating extremal trajectories that reach the target...

Input constraints handling in an MPC/feedback linearization scheme

Jiamei Deng, Victor M. Becerra, Richard Stobart (2009)

International Journal of Applied Mathematics and Computer Science

The combination of model predictive control based on linear models (MPC) with feedback linearization (FL) has attracted interest for a number of years, giving rise to MPC+FL control schemes. An important advantage of such schemes is that feedback linearizable plants can be controlled with a linear predictive controller with a fixed model. Handling input constraints within such schemes is difficult since simple bound contraints on the input become state dependent because of the nonlinear transformation...

Input reconstruction by means of system inversion: A geometric approach to fault detection and isolation in nonlinear systems

András Edelmayer, József Bokor, Zoltán Szabó, Ferenc Szigeti (2004)

International Journal of Applied Mathematics and Computer Science

In this paper the classical detection filter design problem is considered as an input reconstruction problem. Input reconstruction is viewed as a dynamic inversion problem. This approach is based on the existence of the left inverse and arrives at detector architectures whose outputs are the fault signals while the inputs are the measured system inputs and outputs and possibly their time derivatives. The paper gives a brief summary of the properties and existence of the inverse for linear and nonlinear...

Input to state stability properties of nonlinear systems and applications to bounded feedback stabilization using saturation

J. Tsinias (2010)

ESAIM: Control, Optimisation and Calculus of Variations

The concepts of stability, attractivity and asymptotic stability for systems subject to restrictions of the input values are introduced and analyzed in terms of Lyapunov functions. A comparison with the well known input-to-state stability property introduced by Sontag is provided. We use these concepts in order to derive sufficient conditions for global stabilization for triangular and feedforward systems by means of saturated bounded feedback controllers and also recover some recent results...

Input-output decoupling of nonlinear recursive systems

Ülle Kotta (2000)

Kybernetika

The input-output decoupling problem is studied for a class of recursive nonlinear systems (RNSs), i. e. for systems, modelled by higher order nonlinear difference equations, relating the input, the output and a finite number of their time shifts. The solution of the problem via regular static feedback known for discrete-time nonlinear systems in state space form, is extended to RNSs. Necessary and sufficient conditions for local solvability of the problem are proposed. This is the alternative to...

Integrated design of observer based fault detection for a class of uncertain nonlinear systems

Wei Chen, Abdul Q. Khan, Muhammmad Abid, Steven X. Ding (2011)

International Journal of Applied Mathematics and Computer Science

Integrated design of observer based Fault Detection (FD) for a class of uncertain nonlinear systems with Lipschitz nonlinearities is studied. In the context of norm based residual evaluation, the residual generator and evaluator are designed together in an integrated form, and, based on it, a trade-off FD system is finally achieved in the sense that, for a given Fault Detection Rate (FDR), the False Alarm Rate (FAR) is minimized. A numerical example is given to illustrate the effectiveness of the...

Invariant measures and controllability of finite systems on compact manifolds

Philippe Jouan (2012)

ESAIM: Control, Optimisation and Calculus of Variations

A control system is said to be finite if the Lie algebra generated by its vector fields is finite dimensional. Sufficient conditions for such a system on a compact manifold to be controllable are stated in terms of its Lie algebra. The proofs make use of the equivalence theorem of [Ph. Jouan, ESAIM: COCV 16 (2010) 956–973]. and of the existence of an invariant measure on certain compact homogeneous spaces.

Invariant measures and controllability of finite systems on compact manifolds

Philippe Jouan (2012)

ESAIM: Control, Optimisation and Calculus of Variations

A control system is said to be finite if the Lie algebra generated by its vector fields is finite dimensional. Sufficient conditions for such a system on a compact manifold to be controllable are stated in terms of its Lie algebra. The proofs make use of the equivalence theorem of [Ph. Jouan, ESAIM: COCV 16 (2010) 956–973]. and of the existence of an invariant measure on certain compact homogeneous spaces.

Invariant measures and controllability of finite systems on compact manifolds

Philippe Jouan (2012)

ESAIM: Control, Optimisation and Calculus of Variations

A control system is said to be finite if the Lie algebra generated by its vector fields is finite dimensional. Sufficient conditions for such a system on a compact manifold to be controllable are stated in terms of its Lie algebra. The proofs make use of the equivalence theorem of [Ph. Jouan, ESAIM: COCV 16 (2010) 956–973]. and of the existence of an invariant measure on certain compact homogeneous spaces.

Invariant tracking

Philippe Martin, Pierre Rouchon, Joachim Rudolph (2004)

ESAIM: Control, Optimisation and Calculus of Variations

The problem of invariant output tracking is considered: given a control system admitting a symmetry group G , design a feedback such that the closed-loop system tracks a desired output reference and is invariant under the action of G . Invariant output errors are defined as a set of scalar invariants of G ; they are calculated with the Cartan moving frame method. It is shown that standard tracking methods based on input-output linearization can be applied to these invariant errors to yield the required...

Invariant tracking

Philippe Martin, Pierre Rouchon, Joachim Rudolph (2010)

ESAIM: Control, Optimisation and Calculus of Variations

The problem of invariant output tracking is considered: given a control system admitting a symmetry group G, design a feedback such that the closed-loop system tracks a desired output reference and is invariant under the action of G. Invariant output errors are defined as a set of scalar invariants of G; they are calculated with the Cartan moving frame method. It is shown that standard tracking methods based on input-output linearization can be applied to these invariant errors to yield the...

Inversion in indirect optimal control of multivariable systems

François Chaplais, Nicolas Petit (2008)

ESAIM: Control, Optimisation and Calculus of Variations

This paper presents the role of vector relative degree in the formulation of stationarity conditions of optimal control problems for affine control systems. After translating the dynamics into a normal form, we study the Hamiltonian structure. Stationarity conditions are rewritten with a limited number of variables. The approach is demonstrated on two and three inputs systems, then, we prove a formal result in the general case. A mechanical system example serves as illustration.

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