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A Lyapunov functional for a system with a time-varying delay

Józef Duda (2012)

International Journal of Applied Mathematics and Computer Science

The paper presents a method to determine a Lyapunov functional for a linear time-invariant system with an interval timevarying delay. The functional is constructed for the system with a time-varying delay with a given time derivative, which is calculated on the system trajectory. The presented method gives analytical formulas for the coefficients of the Lyapunov functional.

A mathematical model for fluid-glucose-albumin transport in peritoneal dialysis

Roman Cherniha, Joanna Stachowska-Piętka, Jacek Waniewski (2014)

International Journal of Applied Mathematics and Computer Science

A mathematical model for fluid and solute transport in peritoneal dialysis is constructed. The model is based on a threecomponent nonlinear system of two-dimensional partial differential equations for fluid, glucose and albumin transport with the relevant boundary and initial conditions. Our aim is to model ultrafiltration of water combined with inflow of glucose to the tissue and removal of albumin from the body during dialysis, by finding the spatial distributions of glucose and albumin concentrations...

A modified state variable diagram method for determination of positive realizations of linear continuous-time systems with delays

Tadeusz Kaczorek (2012)

International Journal of Applied Mathematics and Computer Science

A new modified state variable diagram method is proposed for determination of positive realizations of linear continuoustime systems with delays in state and input vectors. Using the method, it is possible to find a positive realization with reduced numbers of delays for a given transfer matrix. Sufficient conditions for the existence of positive realizations of given proper transfer matrices are established. The proposed method is demonstrated on numerical examples.

A modified van der Pol equation with delay in a description of the heart action

Beata Zduniak, Marek Bodnar, Urszula Foryś (2014)

International Journal of Applied Mathematics and Computer Science

In this paper, a modified van der Pol equation is considered as a description of the heart action. This model has a number of interesting properties allowing reconstruction of phenomena observed in physiological experiments as well as in Holter electrocardiographic recordings. Our aim is to study periodic solutions of the modified van der Pol equation and take into consideration the influence of feedback and delay which occur in the normal heart action mode as well as in pathological modes. Usage...

A nonsmooth optimisation approach for the stabilisation of time-delay systems

Stefan Vandewalle, Wim Michiels, Koen Verheyden, Joris Vanbiervliet (2008)

ESAIM: Control, Optimisation and Calculus of Variations

This paper is concerned with the stabilisation of linear time-delay systems by tuning a finite number of parameters. Such problems typically arise in the design of fixed-order controllers. As time-delay systems exhibit an infinite amount of characteristic roots, a full assignment of the spectrum is impossible. However, if the system is stabilisable for the given parameter set, stability can in principle always be achieved through minimising the real part of the rightmost characteristic root, or...

A nonsmooth optimisation approach for the stabilisation of time-delay systems

Joris Vanbiervliet, Koen Verheyden, Wim Michiels, Stefan Vandewalle (2007)

ESAIM: Control, Optimisation and Calculus of Variations

This paper is concerned with the stabilisation of linear time-delay systems by tuning a finite number of parameters. Such problems typically arise in the design of fixed-order controllers. As time-delay systems exhibit an infinite amount of characteristic roots, a full assignment of the spectrum is impossible. However, if the system is stabilisable for the given parameter set, stability can in principle always be achieved through minimising the real part of the rightmost characteristic...

A realization problem for positive continuoustime systems with reduced numbers of delays

Tadeusz Kaczorek (2006)

International Journal of Applied Mathematics and Computer Science

A realization problem for positive, continuous-time linear systems with reduced numbers of delays in state and in control is formulated and solved. Sufficient conditions for the existence of positive realizations with reduced numbers of delays of a given proper transfer function are established. A procedure for the computation of positive realizations with reduced numbers of delays is presented and illustrated by an example.

A simple solution to the finite-horizon LQ problem with zero terminal state

Lorenzo Ntogramatzidis (2003)

Kybernetika

This short paper deals with the classical finite-horizon linear-quadratic regulator problem with the terminal state constrained to be zero, for both continuous and discrete-time systems. Closed-form expressions for the optimal state and costate trajectories of the Hamiltonian system, as well as the corresponding control law, are derived through the solutions of two infinite- horizon LQ problems, thus avoiding the use of the Riccati differential equation. The computation of the optimal value of the...

A study on decentralized H feedback control systems with local quantizers

Guisheng Zhai, Ning Chen, Weihua Gui (2009)

Kybernetika

In this paper, we study decentralized H feedback control systems with quantized signals in local input-output (control) channels. We first assume that a decentralized output feedback controller has been designed for a multi-channel continuous-time system so that the closed-loop system is Hurwitz stable and a desired H disturbance attenuation level is achieved. However, since the local measurement outputs are quantized by a general quantizer before they are passed to the controller, the system’s...

A variable structure observer for the control of robot manipulators

Abdelkader Abdessameud, Mohamed Khelfi (2006)

International Journal of Applied Mathematics and Computer Science

This paper deals with the application of a variable structure observer developed for a class of nonlinear systems to solve the trajectory tracking problem for rigid robot manipulators. The analyzed approach to observer design proposes a simple design methodology for systems having completely observable linear parts and bounded nonlinearities andor uncertainties. This observer is basically the conventional Luenberger observer with an additional switching term that is used to guarantee robustness...

A vehicle-track-soil dynamic interaction problem in sequential and parallel formulation

Janusz Kogut, Henryk Ciurej (2010)

International Journal of Applied Mathematics and Computer Science

Some problems regarding numerical modeling of predicted vibrations excited by railway traffic are discussed. Model formulation in the field of structural mechanics comprises a vehicle, a track (often in a tunnel) and soil. Time consuming computations are needed to update large matrices at every discrete step. At first, a sequential Matlab code is generated. Later on, the formulation is modified to use grid computing, thereby a significant reduction in computational time is expected.

Active fault tolerant control of nonlinear systems: The cart-pole example

Marcello Bonfè, Paolo Castaldi, Nicola Mimmo, Silvio Simani (2011)

International Journal of Applied Mathematics and Computer Science

This paper describes the design of fault diagnosis and active fault tolerant control schemes that can be developed for nonlinear systems. The methodology is based on a fault detection and diagnosis procedure relying on adaptive filters designed via the nonlinear geometric approach, which allows obtaining the disturbance de-coupling property. The controller reconfiguration exploits directly the on-line estimate of the fault signal. The classical model of an inverted pendulum on a cart is considered...

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