Wyniki wyszukiwania - BazTech

1

Decentralized static output feedback controller design for linear interconnected systems

Fadhilah Helisyah Nur, Adzkiya Dieky, Arif Didik Khusnul, Zhai Guisheng, Mardlijah

International Journal of Applied Mathematics and Computer Science

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2023

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Vol. 33, no. 1

83--96

EN

Many interconnected systems in the real world, such as power systems and chemical processes, are often composed of subsystems. A decentralized controller is suitable for an interconnected system because of its more practical and accessible implementation. We use the homotopy method to compute a decentralized controller. Since the centralized controller constitutes the starting point for the method, its existence becomes very important. This paper introduces a non-singular matrix and a design parameter to generate a centralized controller. If the initial centralized controller fails, we can change the value of the design parameter to generate a new centralized controller. A sufficient condition for a decentralized controller is given as a bilinear matrix inequality with three matrix variables: a controller gain matrix and a pair of other matrix variables. Finally, we present numerical examples to validate the proposed decentralized controller design method.

2

Multiple soft fault diagnosis of analog circuits using restart homotopy method

Tadeusiewicz M., Hałgas S.

Elektronika : konstrukcje, technologie, zastosowania

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2013

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Vol. 54, nr 12

87-91

EN

This paper offers a method for multiple soft fault diagnosis of nonlinear circuits containing bipolar and MOS transistors. The method enables us to locate faulty elements and evaluate their parameters, using a nonlinear algebraic type test equation which may possess several solutions. To find the solutions the homotopy concept is applied and a homotopy differential equation written. Next the terminal value problem is formulated and solved using the restart approach. As a result different sets of parameters which satisfy the diagnostic test can be found rather than one specific set. Two numerical examples show that the proposed approach is simple and improves the diagnosis of analog circuits.

PL

Praca dotyczy diagnostyki wielokrotnych uszkodzeń parametrycznych w układach nieliniowych zawierających tranzystory bipolarne i tranzystory MOS. Zaproponowano metodę umożliwiającą lokalizowanie uszkodzonych elementów i określanie ich wartości na podstawie analizy testowego, nieliniowego równania algebraicznego, które może posiadać wielokrotne rozwiązania. W celu wyznaczenia tych rozwiązań zastosowano koncepcję homotopii i utworzono homotopijne równanie różniczkowe. Sformułowano zagadnienie końcowe i rozwiązano je numerycznie używając procedurę restartu. Takie podejście umożliwia znalezienie różnych zbiorów wartości elementów potencjalnie uszkodzonych, które spełniają test diagnostyczny. Zamieszczone w pracy dwa przykłady obliczeniowe pokazują, że zaproponowana metoda jest prosta, nie wymaga dużych mocy obliczeniowych oraz usprawnia diagnostykę analogowych układów nieliniowych.

3

Finding multiple DC operating points of simulated submicrometer technology MOS circuits

Tadeusiewicz M., Ossowski M.

Elektronika : konstrukcje, technologie, zastosowania

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2013

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Vol. 54, nr 12

92-96

EN

The paper is focused on the analysis of circuits containing MOS transistors fabricated in submicrometer technology, having multiple DC operating points. The transistors are characterized by intricate models BSIM 3 and BSIM 4. To find the operating points an algorithm is proposed, based on the homotopy concept and the simplicial method. The algorithm is capable of finding multiple DC operating points but it does not guarantee finding all of them. The simplicial–homotopy procedure has been implemented in MATLAB, whereas the required circuit analyses are carried out using WinSpice and both environments have been joined together. For illustration three numerical examples are given.

PL

Praca dotyczy analizy obwodów, o wielu rozwiązaniach DC, zawierających tranzystory MOS, wykonane w technologii submikronowej. Tranzystory są reprezentowane za pomocą bardzo złożonych modeli BSIM 3 i BSIM 4. Zaproponowano metodę analizy numerycznej tej klasy obwodów, opartą na koncepcji homotopii i metodzie simplicjalnej. Metoda umożliwia obliczanie wielokrotnych rozwiązań DC, ale nie gwarantuje wyznaczenia wszystkich rozwiązań. Simplicjalno-homotopijna procedura została zaimplementowana w środowisku MATLAB, podczas gdy wymagane analizy obwodów są realizowane przy użyciu programu WinSpice, przy czym oba środowiska zostały połączone automatycznie. Dla ilustracji zamieszczono trzy przykłady obliczeniowe.

4

Oblique stagnation flow of a thermodynamically-valid Walters' B liquid: a series solution

Mortazavi N., Sadeghy K., Alikbar V., Alizadeh-Pahlavan A.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 3

829-852

EN

A thermodynamically-valid exact solution was found for laminar, two-dimensional, oblique stagnation point flow of a Walters' B fluid above a stretching sheet. To circumvent the problem with the extra boundary condition, and also to be able to obtain results at large elasticity numbers, use will be made of the homotopy analysis method in order to find an analytical solution. The analytical solution so obtained shows that the behavior of fluids with a negative elasticity number is completely different from those with a positive elasticity number. For example, while for the wall shear stress is increased by an increase in the elasticity number, for it is predicted to decrease when the elasticity number is increased. A comparison of the results obtained using the homotopy analysis method with those obtained using the perturbation method (Mahapatra et al., 2007) suggests that the perturbation method may not be so reliable when addressing viscoelastic fluids.

5

A stable homotopy approach to horizontal linear complementarity problems

Ralph D.

Control and Cybernetics

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2002

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Vol. 31, no 3

575-599

EN

We are interested in the solution of Horizontal Linear Complementarity Problems, HLCPs, that is complementarity problems with more variables than equations. Globally metrically regular HLCPs have nonempty solution sets that are stable with respect to "right-hand-side perturbations" of the data, hence are numerically attractive. The main purpose of the paper is to show how the stability on conditioning properties of globally metrically regular HLCPs are preserved by a homotopy framework for solving the HLCP that finds a "stable" direcaion at each iteration as a local minimizer of a strongly convex quadratic program with linear complementarity constraints, QPCC. Apart from intrinsic interest in numerical solution of HLCPs, this investigation has application in solving horizontal nonlinear complementarity problems and more broadly in the area of mathematical programs with complementarity constraints, MPCCs.