Przeglądaj {{ collection }} wg Autor "Stefański, Andrzej"

Teraz wyświetlane 1 - 8 z 8

Basic Study of Synchronization in a Two Degree of Freedom, Duffing Based System
(Wydawnictwo Politechniki Łódzkiej ; Katedra Dynamiki Maszyn - Wydział Mechaniczny Politechniki Łódzkiej, 2015) Dąbrowski, Artur; Mnich, Konrad; Stefański, Andrzej
The issue of synchronization has been analyzed from many points of view since it was first described in 17th century. Nowadays the theory that stands behind it is so developed, it might be difficult to understand where it all comes from. This paper reminds the key concepts of synchronization by examination of two coupled Duffing oscillators. It describes also the origins of Duffing equation and proves its ability to behave chaotically.
Basic Study of Synchronization in a Two Degree of Freedom, Duffing Based System
(Lodz University of Technology. Faculty of Mechanical Engineering. Department Division of Dynamics., 2015) Dąbrowski, Artur; Mnich, Konrad; Stefański, Andrzej
The issue of synchronization has been analyzed from many points of view since it was first described in 17th century. Nowadays the theory that stands behind it is so developed, it might be difficult to understand where it all comes from. This paper reminds the key concepts of synchronization by examination of two coupled Duffing oscillators. It describes also the origins of Duffing equation and proves its ability to behave chaotically.
Dynamics and control experimental laboratory
(Wydawnictwo Politechniki Łódzkiej, 2006) Marynowski, Krzysztof; Stefański, Andrzej; Wojewoda, Jerzy; Jagiełło, Bogdan; Red. nauk. Wydziału: Wojewoda, Jerzy; Warmiński, Jerzy; Wiercigroch, Marian
The book we are proud to present is the effect of many years of experience gathered during teaching the Dynamics and Control at the International Faculty of Engineering in Technical University in Łódź. Dynamics and control are usually two separate subjects in programs of technical studies. The third year of the course of Mechanical Engineering and Applied Computer Science is combined into a single subject. Our over ten years didactic experience shows it gives finally very good results. The manuał contains a set of instructions how to perform 14 laboratory exercises from various issues of dynamics and control. They contain wide theoretical background and already solved exercises helping to complete the given tasks. In fact, the book is intended for students of the third year, but all interested in solving the practical issues of dynamics and automatics also can use it. We appreciate the support extended to us by all our colleagues from the Division of Dynamics of the Technical University of Łódź and gratefully acknowledge the individual help given to us by Małgorzata Jóźwik for careful and proficient translating.
Energy balance of two synchronized self-excited pendulums with different masses.
(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2012) Kapitaniak, Tomasz; Czołczyński, Krzysztof; Perlikowski, Przemysław; Stefański, Andrzej
We consider the synchronization of two self-excited pendulums with different masses. We show that such pendulums hanging on the same beam can show almost-complete (in-phase) and almost-antiphase synchronizations in which the difference of the pendulums displacements is small. Our approximate analytical analysis allows one to derive the synchronization conditions and explains the observed types of synchronizations as well as gives an approximate formula for amplitudes of both the pendulums and the phase shift between them. We consider the energy balance in the system and show how the energy is transferred between the pendulums via the oscillating beam allowing synchronization of the pendulums.
Energy method for position stability analysis of critical points of robot manipulators.
(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2004) Szumiński, Przemysław; Kapitaniak, Tomasz; Stefański, Andrzej
An energy method for the position stability analysis of critical points (equilibrium positions) of dynamical systems with an arbitrary finite number of degrees of freedom is presented. The method proposed consists in the analysis of the potential energy balance of a perturbation of an arbitrary number of generalised co-ordinates of the dynamical system in order to establish the energy stability of individual degrees of freedom and of the whole system. In the case of mechanical systems, the position stability criterion, understood as minimisation of loads of driving systems with conservative forces, is discussed. Some examples of application of the method to the position stability analysis of critical points of one- and two-degree-of-freedom systems are analysed.
Identyfikacja procesu wibracyjnego zagęszczania wątku w technologii tkackiej
(Wydawnictwo Politechniki Łódzkiej, 2018) Kuchar, Maciej; Red. nauk. Wydziału Technologii Materiałowych i Wzornictwa Tekstyliów : Matusiak, Małgorzata; Stefański, Andrzej; Wojtysiak, Jan
Warunki wytwarzania tkanin, szczególnie gęsto tkanych na współczesnych krosnach, wskazują na potrzebę redukcji znacznych obciążeń dynamicznych płochy i osnowy. Tematyka niniejszej pracy obejmuje zagadnienie znaczącego udoskonalenia procesu zagęszczania tkanin poprzez wykorzystanie ruchu drgającego płochy. Realizacja takiego procesu wymagała budowy wibracyjnego mechanizmu bidłowego, osiągającego parametry dynamiczne, odpowiadające relatywnie dużym prędkościom współczesnych bideł. Mechanizm bidłowy wyposażono więc w układ wibracyjny płochy, o sztywności zapewniającej odpowiednią częstotliwość rezonansową. Obserwacje działania mechanizmu pozwoliły na poznanie zjawisk fizycznych i reologicznych oraz identyfikację parametrów dynamicznych w procesie zagęszczania wątków ruchem wibracyjnym płochy. Badania przeprowadzono w warunkach dynamicznych, odpowiadających współczesnym warunkom tkania.[...]
Lyapunov exponents of systems with noise and fluctuating parameters.
(Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej, 2008) Stefański, Andrzej
This paper deals with the problem of determination of Lyapunov exponents in dynamical systems with noise or fluctuating parameters. The method for identifying the character of motion in such systems is proposed. This approach is based on the phenomenon of complete synchro- nization in double-oscillator systems via diagonal, master-slave coupling between them. The idea of effective Lyapunov exponents is introduced for quantifying the local stability in the presence of noise. Examples of the method application and its comparison with bifurcation diagrams representing the system dynamics are demonstrated. Finally, the pro- perties of the method are discussed.
Synchronization in arrays of coupled self-induced friction oscillators
(Springer, 2016-11) Marszal, Michał; Saha, Ashesh; Jankowski, Krzysztof; Stefański, Andrzej; Katedra Dynamiki Maszyn. Wydział Mechaniczny. Politechnika Łódzka.; Division of Dynamics. Faculty of Mechanical Engineering. Lodz University of Technology.
We investigate synchronization phenomena in systems of self-induced dry friction oscillators with kinematic excitation coupled by linear springs. Friction force is modelled according to exponential model. Initially, a single degree of freedom mass-spring system on a moving belt is considered to check the type of motion of the system (periodic, non-periodic). Then the system is coupled in chain of identical oscillators starting from two, up to four oscillators. A reference probe of two coupled oscillators is applied in order to detect synchronization thresholds for both periodic and non-periodic motion of the system. The master stability function is applied to predict the synchronization thresholds for longer chains of oscillators basing on two oscillator probe. It is shown that synchronization is possible both for three and four coupled oscillators under certain circumstances. Our results confirmed that this technique can be also applied for the systems with discontinuities.