PL
 |
EN
Preferencje help
Polish version English version Język
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 8

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
1
Content available remote Synthesis of H2 Controler for VSC-HVDC Terminal Using LMI
Aleksić K., Nikolić V.
Machine Dynamics Problems
|
2007
|
Vol. 31, No. 1
5-13
EN
In this paper an approach to designing controller for a VSC HVDC terminal which is robust over a range of operating points is presented. The operating range of the terminal is first characterized as an uncertainty region around a linear nominal model using the operating points of a non-linear model. Linear fractional transformation (LFT) uncertainty model is constructed using a technique based on the singular value decomposition. An LMI based formulation is then used to synthesize controller which optimizes the performance over a range of operating conditions. Numerical simulation confirms that the designed controller achieves good trade-off between the robustness and performance on the non-linear model.
2
Content available remote Determination of the Cutting Forces in a Face Milling Operation Using the Artificial Neural Networks
Manić M., Tanikić D., Nikolić V.
Machine Dynamics Problems
|
2005
|
Vol. 29, No. 3
51--58
EN
The magnitude of the cutting force, which occurs during the face milling process, depends on many factors such as the cutting depth, the velocity of accessory motion, the number of revolutions of the main spindle, the feed rate, type of material of the cutting tool and the machined part etc. Anyway, calculating this force is not a simple problem and that is the reason why, in some cases, it is expedient to use empirical forms or interpolation formulas obtained by processing of measuring results in laboratory conditions. In order to calculate cutting force, the results have been processed in two ways: using a multifactorial experiment and using artificial neural networks. Results of this work show that an artificial neural network can be very useful in the cutting force prediction.
3
Content available remote Analyzing, Modeling and Simulation of the Cascade Connected Transporters in Tyre Industry Using Signal and Bond Graphs
Trajkocić D., Nikolić V., Antić D., Danković B.
Machine Dynamics Problems
|
2005
|
Vol. 29, No. 3
91--106
EN
In the paper the bond graphs modeling and simulation a cascade system for protector cooling in tyre industry using Bondsim Simulink library have been presented. The example of cascade system that the use of Bondsim library will simplify the modeling and simulation has been shown. Using signal graph for obtaining the state space model is presented.
4
Content available remote Obtaining State Space Model from Bond Graph Model with Derivative Causality Using Laplace Transform
Antić D., Stanković L., Nikolić V.
Machine Dynamics Problems
|
2003
|
Vol. 27, No. 2
5-10
EN
One method for obtaining the state space model from the bond graph model is based on using signal graph as an indirect tool. In case the signal graph nodes are time functions, the direct state space model obtaining is only possible for bond graphs with integral causality. Interposing the Laplace operator "s" into the signal graph is proposed in this paper. Thus, in case of derivative causality presence in the bond graph as well, the necessary transformations of the equations are minimized.
5
Content available remote Application of Signal Flow Graph Theory for Obtaining State Space Model from Bond Graph Model with Derivative Causality
Antić D., Stanković L., Danković B., Nikolić V.
Machine Dynamics Problems
|
2003
|
Vol. 27, No. 1
5--13
EN
In this paper, a new approach for deriving state space equations from a causal bond graph, in which there is derivative causality as well, on the basis of the equivalent signal flow graph is presented. By following ”the paths of traveling” of two general bond graph variables (the effort e and the flow f) through the causal bond graph, the equivalent signal flow graph is obtained. On the basis of that signal flow graph, a system of equations, in which the first derivatives of the state variables are implicitly expressed, by which the arranging of the state space model is obtained, is formed.
6
Content available remote Sliding Mode Control with Fuzzy Tuning for Position Tracking of an Electro-Hydraulic Actuator
Antić D., Nikolić V., Mihajlov M., Aleksić K.
Machine Dynamics Problems
|
2002
|
Vol. 26, No. 1
81-93
EN
This paper considers the position control problem of an electro-hydraulic actuator subjected to parameter uncertainties and an external disturbance. The system is described by a comprehensive model that accounts for nonlinearities and friction effects. Friction in the hydraulic cylinder and load variations are taken into account as the external disturbance. The variable structure control with a sliding mode is used in the first step of the controller design. In order to overcome known drawbacks of the sliding mode control, fuzzy logic is applied. The simulation results show good tracking performance and strong robustness.
7
Content available remote Pylonomial Equation Approach to the Dual Criterion Stochastic Optimal Control Problem: Application to an Extruder
Nikolić V., Ristić D.
Machine Dynamics Problems
|
2001
|
Vol. 25, No. 2
75-89
EN
In this paper a polynomial approach to the solvingof dual criterion stochastic optimal control problem for a general single-input single-output linear discrete stochastic system is considered. The discussed optimal control problem solution involves solving of three polynomial Diophantine equations and two polynomial spectral factorizations resulting from the appropriate transfer-function or polynomial system representation.n The presented results are applied in procedure of designing of the optimal control based on the model of a single-screw extruder represented in polynomial form.
PL
W artykule rozważono problem zastosowania wielomianów do rozwiązania zagadnienia optymalizacji sterowania z podwójnym kryterium stochastycznym w ogólnym liniowym dyskretnym układzie stochastycznym z pojedynczym wejściem i wyjściem. Zagadnienie to opiera się na rozwiązaniu trzech równań diofantycznych i dwóch rozkładach widmowych wynikających z funkcji przejścia układu modelowanego reprezentacją wielomianową. Otrzymane rezultaty zastosowano do projektowania optymalnego układu sterowania prasy do wyciskania z pojedynczą śrubą opisanej modelem wielomianowym.
8
Content available remote Discrete Self-tuning Regulator Design for Some Hydraulic Systems
Nikolić V., Nestorović T.
Machine Dynamics Problems
|
2001
|
Vol. 25, No. 2
57-73
EN
The paper considers self-tuning regulator design and its applications to some hydraulic systems. Self-tuning regulator design procedure based on pole placement was considered first. Regulator design was trated in case of known and unknown parameters. In case of unknown parameters recuesive least-square algorithm was used for parameter estimation. Certainty equivalence princyple was also applied in order to keep the R-S-T regulator structure obtained in case of known parameters, but with parameter estimates used instead of their real values. Self-tuning regulator design procedure was applied to hydraulic control systems. First the level system described by second order model was considered and then hydraulic positioning system of the fourth order. In both cases explicit pole placement method was applied. Obtained control laws were verified by simulation results which showed good tracking properties.
PL
W artykule rozważano zagadnienie projektowania regulatora samodostrajającego w kontekście jego zastosowań w układach hydraulicznych. Najpierw zbadano procedurę projektowania regulatora opartą na ustawianiu biegunowym. w przypadku nieznanych parametrów układu użyto rekurencyjnej metody najmniejszych kwadratów do ich wyznaczenia. Zasada pewności zastepczej została zastosowana do określania struktury regulatora RST w przypadku parametrów znanych ale w postaci ich estymat, a nie wartości rzeczywistych. Procedurę projektowania regulatora samodostrajającego przedstawiono na przykładzie układów hydraulicznych. Najpierw rozważono układ dźwigni na podstawie modelu drugiego rzędu, by nastepnie zbadać model czwartego rzędu układu hydraulicznego pozycjonowania. W obydwu przypadkach zastosowano jawną metodę ustawiania biegunowego. Otrzymane prawa sterowania zweryfikowano z wynikami badań symulacyjnch, które wykazały dobre właściwości nadążne układu sterowania.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.