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Nonlinear system identification using heterogeneous multiple models

Rodolfo Orjuela, Benoît Marx, José Ragot, Didier Maquin (2013)

International Journal of Applied Mathematics and Computer Science

Multiple models are recognised by their abilities to accurately describe nonlinear dynamic behaviours of a wide variety of nonlinear systems with a tractable model in control engineering problems. Multiple models are built by the interpolation of a set of submodels according to a particular aggregation mechanism, with the heterogeneous multiple model being of particular interest. This multiple model is characterized by the use of heterogeneous submodels in the sense that their state spaces are not...

Nonparametric instrumental variables for identification of block-oriented systems

Grzegorz Mzyk (2013)

International Journal of Applied Mathematics and Computer Science

A combined, parametric-nonparametric identification algorithm for a special case of NARMAX systems is proposed. The parameters of individual blocks are aggregated in one matrix (including mixed products of parameters). The matrix is estimated by an instrumental variables technique with the instruments generated by a nonparametric kernel method. Finally, the result is decomposed to obtain parameters of the system elements. The consistency of the proposed estimate is proved and the rate of convergence...

Non-quadratic performance design for Takagi-Sugeno fuzzy systems

Miguel Bernal, Petr Hušek (2005)

International Journal of Applied Mathematics and Computer Science

This paper improves controller synthesis of discrete Takagi-Sugeno fuzzy systems based on non-quadratic Lyapunov functions, making it possible to accomplish various kinds of control performance specifications such as decay rate conditions, requirements on control input and output and disturbance rejection. These extensions can be implemented via linear matrix inequalities, which are numerically solvable with commercially available software. The controller design is illustrated with an example.

Nonquadratic stabilization of continuous-time systems in the Takagi-Sugeno form

Miguel Bernal, Petr Hušek, Vladimír Kučera (2006)

Kybernetika

This paper presents a relaxed scheme for controller synthesis of continuous- time systems in the Takagi-Sugeno form, based on non-quadratic Lyapunov functions and a non-PDC control law. The relaxations here provided allow state and input dependence of the membership functions’ derivatives, as well as independence on initial conditions when input constraints are needed. Moreover, the controller synthesis is attainable via linear matrix inequalities, which are efficiently solved by commercially available...

Nonregular decoupling with stability of two-output systems

Javier Ruiz, Jorge A. Torres Muñoz, Francisco Lizaola (2002)

Kybernetika

In this paper we present a solution to the decoupling problem with stability of linear multivariable systems with 2 outputs, using nonregular static state feedback. The problem is tackled using an algebraic-polynomial approach, and the main idea is to test the conditions for a decoupling compensator with stability to be feedback realizable. It is shown that the problem has a solution if and only if Morse’s list I 2 is greater than or equal to the infinite and unstable structure of the proper and stable...

Norm estimates for solutions of matrix equations AX-XB=C and X-AXB=C

Michael I. Gil' (2014)

Discussiones Mathematicae, Differential Inclusions, Control and Optimization

Let A, B and C be matrices. We consider the matrix equations Y-AYB=C and AX-XB=C. Sharp norm estimates for solutions of these equations are derived. By these estimates a bound for the distance between invariant subspaces of matrices is obtained.

Normalized finite fractional differences: Computational and accuracy breakthroughs

Rafał Stanisławski, Krzysztof J. Latawiec (2012)

International Journal of Applied Mathematics and Computer Science

This paper presents a series of new results in finite and infinite-memory modeling of discrete-time fractional differences. The introduced normalized finite fractional difference is shown to properly approximate its fractional difference original, in particular in terms of the steady-state properties. A stability analysis is also presented and a recursive computation algorithm is offered for finite fractional differences. A thorough analysis of computational and accuracy aspects is culminated with...

Notes on μ and l 1 robustness tests

Gábor Z. Kovács, Katalin M. Hangos (1998)

Kybernetika

An upper bound for the complex structured singular value related to a linear time-invariant system over all frequencies is given. It is in the form of the spectral radius of the -norm matrix of SISO input-output channels of the system when uncertainty blocks are SISO. In the case of MIMO uncertainty blocks the upper bound is the -norm of a special non-negative matrix derived from -norms of SISO channels of the system. The upper bound is fit into the inequality relation between the results of...

Novel fault detection criteria based on linear quadratic control performances

Dušan Krokavec, Anna Filasová (2012)

International Journal of Applied Mathematics and Computer Science

This paper proposes a new approach to designing a relatively simple algorithmic fault detection system that is potentially applicable in embedded diagnostic structures. The method blends the LQ control principle with checking and evaluating unavoidable degradation in the sequence of discrete-time LQ control performance index values due to faults in actuators, sensors or system dynamics. Design conditions are derived, and direct computational forms of the algorithms are given. A simulation example...

Novel optimal recursive filter for state and fault estimation of linear stochastic systems with unknown disturbances

Karim Khémiri, Fayçal Ben Hmida, José Ragot, Moncef Gossa (2011)

International Journal of Applied Mathematics and Computer Science

This paper studies recursive optimal filtering as well as robust fault and state estimation for linear stochastic systems with unknown disturbances. It proposes a new recursive optimal filter structure with transformation of the original system. This transformation is based on the singular value decomposition of the direct feedthrough matrix distribution of the fault which is assumed to be of arbitrary rank. The resulting filter is optimal in the sense of the unbiased minimum-variance criteria....

NTGsim: a graphical user interface and a 3D simulator for nonlinear trajectory generation methodology

Lyall Jonathan Di Trapani, Tamer Inanc (2010)

International Journal of Applied Mathematics and Computer Science

Nonlinear Trajectory Generation (NTG), developed by Mark Milam, is a software algorithm used to generate trajectories of constrained nonlinear systems in real-time. The goal of this paper is to present an approach to make NTG more userfriendly. To accomplish this, we have programmed a Graphical User Interface (GUI) in Java, using object oriented design, which wraps the NTG software and allows the user to quickly and efficiently alter the parameters of NTG. This new program, called NTGsim, eliminates...

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