Wyniki wyszukiwania - BazTech

1

An investigation into vibration control of gear bearing systems

Saghafi Amin, Farshidianfar Anooshirvan

Archive of Mechanical Engineering

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2021

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LXVIII, nr 4

473--491

EN

Considering the importance of gear systems as one of the important vibration and noise sources in power transmission systems, an active control for suppressing gear vibration is presented in this paper. A gear bearing model is developed and used to design an active control gear-bearing system. Two possible configurations of control system are designed based on active bearing and active gear-shaft torsional coupling to control and reduce the disturbance affecting system components. The controller for computing the actuation force is designed by using the H-infinity control approach. Simulation results indicate that the desired controller can efficiently be used for vibration control of gear bearing systems.

2

Effect of the thickness of the piezoelectric patches on the active control of a thin plate

Latrache M., Amrane M. N.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

1345--1354

EN

This paper presents a numerical study pertaining to on the active vibration control (AVC) of the 3-D rectangle simply supported plate bonded of the piezoelectric sensor/actuator pairs. A LQR controller is designed based on the independent mode space control techniques to stifle the vibration of the system. The change in the thickness of the patches was a clear impact on the control results, and also in the values of the voltage in actuator. The results were established by simulating in ANSYS and MATLAB.

3

Feedforward Control of a Light-Weight Device Casing for Active Noise Reduction

Wrona S., Pawelczyk M.

Archives of Acoustics

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2016

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Vol. 41, No. 3

499--505

EN

It is possible to enhance acoustic isolation of the device from the environment by appropriately controlling vibration of a device casing. Sound insulation efficiency of this technique for a rigid casing was confirmed by the authors in previous publications. In this paper, a light-weight casing is investigated, where vibrational couplings between walls are much greater due to lack of a rigid frame. A laboratory setup is described in details. The influence of the cross-paths on successful global noise reduction is considered. Multiple vibration actuators are installed on each of the casing walls. An adaptive control strategy based on the Least Mean Square (LMS) algorithm is used to update control filter parameters. Obtained results are reported, discussed, and conclusions for future research are drawn.

4

Badania symulacyjne aktywnego systemu antypompażowego dmuchawy odśrodkowej

Grapow F., Liśkiewicz G.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

|

2015

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nr 147

1--12

PL

W pracy zaprezentowano projekt systemu antypompażowego kontroli aktywnej oparty na modelu Greitzer’a dla dmuchawy odśrodkowej. Jego istotą jest dodatkowy zawór upustowy sterowany regulatorem proporcjonalnym, a symulacja jego działania przeprowadzona w programie Simulink potwierdziła możliwość zastosowania takiego systemu dla maszyny pracującej w obszarze pompowania. Uzyskane wyniki pokazują, że zaprojektowany system tłumi oscylacje ciśnienia i pozwala na pracę maszyny w obszarze pompowania.

EN

In this paper the active control, anti-surge system for centrifugal blower has been designed and simulated. It has been accomplished by additional blow-off valve controlled by proportional controller. System was simulated in Simulink and it shows possibility to apply this system into machine working in surge region. The results show that designed system has ability to damp pressure oscillations and provide stable working conditions of centrifugal blower.

5

Control of a two-degree-of-freedom system with combined excitations

Bauomy H. S., El-Sayed A. T.

Archives of Civil and Mechanical Engineering

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2015

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Vol. 15, no. 2

492--508

EN

In this paper, the chaotic dynamics of parametrically, externally and tuned excited suspended cable is studied with negative cubic velocity feedback. The equations of motion of this system are exhibited by two-degree-of-freedom system including quadratic and cubic nonlinearities. Using the multiple scale perturbation technique, the response of the nonlinear system near the simultaneous primary, sub-harmonic, combined and internal resonance case of this system is extracted up to the second order approximation. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system behavior are investigated and reported. The simulation results are achieved using MATLAB (R2012a) programs.

6

Atcive control of smart tensegrity structures

Sabouni-Zawadzka A.

Archives of Civil Engineering

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2014

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Vol. 60, nr 4

517--534

EN

The topic of smart structures, their active control and implementation, is relatively new. Therefore, different approaches to the problem can be met. The present paper discusses variable aspects of the active control of structures. It explains the idea of smart systems, introduces different terms used in smart technique and defines the structural smartness. The author indicates differences between actively controlled structures and structural health monitoring systems and shows an example of an actively controlled smart footbridge. The analyses presented in the study concern tensegrity structures, which are prone to the structural control through self-stress state adjustment. The paper introduces examples of structural control performed on tensegrity modules and plates. An influence of several self-stress states on displacements is analyzed and a study concerning damage due to member loss is presented.

7

Application of an memetic algorithm to placement of sensors for active noise-vibration control

Wrona S., Pawełczyk M.

Mechanics and Control

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2013

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Vol. 32, no. 3

122--128

EN

For successful active control of a vibrating structure it is essential to appropriately place sensors. One of the most important criteria is to make the system observable, so any control objectives can be achieved. In this paper the observability-oriented placement of sensors is undertaken. First, a theoretical model of a fully clamped plate is presented. Optimization criterion based on maximization of observability of the system is developed. A memetic algorithm is used to find the optimal solution. Obtained results are compared with those obtained by the genetic algorithm.The configuration is also validated experimentally.

PL

W celu skutecznej aktywnej redukcji drgań i hałasu konstrukcji konieczne jest odpowiednie rozmieszczenie czujników. Jednym z najważniejszych kryteriów jest uczynienie obiektu obserwowalnym, aby jakiekolwiek cele sterowania mogły zostać osiągnięte.W pracy podjęte zostało zagadnienie rozmieszczenia czujników w oparciu o analizę obserwowalności. Zaprezentowany został model teoretyczny płyty o brzegach całkowicie utwierdzonych. Wyprowadzone zostało kryterium optymalizacji w oparciu o maksymalizacje miary obserwowalności. Do znalezienia rozwiązania optymalnego zastosowano algorytm memetyczny. Otrzymane wyniki zostały porównane z wynikami uzyskanymi za pomocą algorytmu genetycznego. Wyznaczone rozmieszczenie czujników zostało zweryfikowane eksperymentalnie.

8

Active vibroacoustic control of plate structures with arbitrary boundary conditions

Nowak Ł., Zieliński T. G., Meissner M.

IPPT Reports on Fundamental Technological Research

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2013

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nr 4

5--9

EN

The paper describes briefly some main aspects of the active feedback control system that has been developed and constructed for reduction of vibroacoustic emission of vibrating plate structures with arbitrary boundary conditions. Relations between the forms and frequency of the vibrations induced by an external harmonic excitation and the distribution of the generated acoustic pressure field are investigated using the developed numerical model based on indirect variational boundary element method. The aim of the control system is to minimize the sound pressure level in a given point of the ambient space. The system uses small, rectangle-shaped piezoelectric transducers as both sensors and actuators. The transducers are connected in a number of independent feedback loops, and the feedback gains are the control parameters which are optimized using the developed optimal control algorithm. The constructed active system has been tested for the stability and control performance during experimental research performed in an anechoic chamber. Results of experiments are presented in the paper, proving a high level of noise reduction and a good agreement with numerical predictions.

9

Controllability-oriented placement of actuators for active noise-vibration control of rectangular plates using a memetic algorithm

Wrona S., Pawełczyk M.

Archives of Acoustics

|

2013

|

Vol. 38, No. 4

529--536

EN

For successful active control with a vibrating plate it is essential to appropriately place actuators. One of the most important criteria is to make the system controllable, so any control objectives can be achieved. In this paper the controllability-oriented placement of actuators is undertaken. First, a theoretical model of a fully clamped rectangular plate is obtained. Optimization criterion based on maximization of controllability of the system is developed. The memetic algorithm is used to find the optimal solution. Obtained results are compared with those obtained by the evolutionary algorithm. The configuration is also validated experimentally.

10

Synchronization of coupled chaotic systems using active control

Pal S., Ali Khan M.

International Journal of Applied Mechanics and Engineering

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2012

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Vol. 17, no. 4

1347-1355

EN

In this paper, we introduce synchronization of two coupled identical Nuclear Spin Generating systems using active control. We also introduce synchronization scheme for a coupled chaotic Lorenz and Rossler system with a fairly general coupling and using active control. Numerical simulation results are presented to demonstrate the effectiveness of the proposed synchronization scheme.

11

Piezoelectric controlled noise attenuation of engineering systems

Ringwelski S., Luft T., Gabbert U.

Journal of Theoretical and Applied Mechanics

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2011

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Vol. 49 nr 3

859-878

EN

In the paper, a recently developed overall numerical approach is presented, which is suitable to design smart engineering systems to actively reduce sound radiation. For this reason, piezoelectric patch actuators and sensors are attached to the surface of the structure to control structural vibrations. In the paper, the theoretical background of the design process is briefly presented first. The basis is a combined finite element and boundary element approach. Electromechanical coupled finite elements are applied to model the structure as well as the piezoelectric patches. The finite element method is also used to model fluid domains which are partially or totally bounded by the structure. Boundary elements are used to characterize the unbounded acoustic pressure fields. Then it is shown how control algorithms can be included into the simulation process, which finally results in an overall simulation approach for structural acoustic systems including control. The numerical approach is also verified by measurements. The experimental setup enables measurements of the uncontrolled and controlled radiated sound fields using a microphone array. A comparison between the measured values and those predicted by the proposed coupled finite element-boundary element approach shows good agreement. Finally, it is demonstrated how the approach can be applied to real engineering systems. As an example, noise reduction of a car engine with a smart oil pan is presented. Again, the numerical results of the uncontrolled and controlled behavior are in good agreement with the measurements. It can be concluded that the proposed overall numerical approach can be applied to design real engineering systems, which are able to actively reduce the noise level.

PL

W pracy przedstawiono ostatnio opracowaną przez autorów metodę obliczeniową do projektowania konstrukcji „inteligentnych”, których zadaniem jest redukcja emisji hałasu. Do samego tłumienia hałasu użyte są elementy piezoelektryczne przyklejane do powierzchni danej konstrukcji. Na początek omówiono podstawy teoretyczne projektowania takich układów. Podstawę stanowi kombinacja metody elementów skończonych i brzegowych. Elementy skończone ze sprzężeniem elektromechanicznym służą do modelowania piezoelektryków i konstrukcji bazowej. Metodę elementów skończonych zastosowano także do modelowania płynu znajdującego się wewnątrz projektowanego urządzenia przy częściowym lub całkowitym zamknięciu płynu ścianami konstrukcji. Elementy brzegowe użyto do opisu otwartego pola akustycznego. Następnie pokazano sposób, w jaki algorytmy sterowania należy wprowadzić do ogólnej procedury obliczeniowej do projektowania urządzeń z aktywnym układem redukcji hałasu. Otrzymane rezultaty symulacji numerycznych zweryfikowano pomiarami z doświadczeń. Stanowisko badawcze zostało wyposażone w odpowiedni układ mikrofonów, co umożliwiło pomiar poziomu hałasu z włączonym i wyłączonym układem sterowania. Stwierdzono dobrą zgodność wyników eksperymentu z zaproponowaną metodą numeryczną wykorzystującą elementy skończone i brzegowe. Na koniec omówiono przykład zastosowania zaproponowanej metody do projektowania rzeczywistej konstrukcji. Zaprezentowano silnik samochodowy z układem aktywnej redukcji hałasu umiejscowionym na misce olejowej. Powtórnie zbadano zgodność wyników symulacji numerycznych z pomiarami doświadczalnymi, stwierdzając dobrą zgodność pomiędzy nimi. W konkluzji uznano, że zaproponowana metoda nadaje się do zintegrowania z ogólnymi algorytmami projektowania rzeczywistych konstrukcji inżynierskich, w których nacisk położono na redukcję poziomu hałasu.

12

Comparison of passive and active methods for sound radiation reduction from the clamped plate

Kozupa M., Wiciak J.

Mechanics and Control

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2010

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Vol. 29, no. 3

128-131

EN

The paper is an analytical and experimental study of smart structure, which consist of steel plate with bonded PZTs and porous elastomer layer. Active control of sound radiation from a clamped at the edge square plate is examined. Simulations and numerical computation of the experiment are performed in ANSYS environment. Calculations of plate vibration and sound radiation under stepped harmonic force are performed. The experimental set-up is placed in coupled reverberation chambers and the test plate is placed in the hole. A variety o test cases were studied for three different plates: steel plate + PZT, steel plate + elastomer layer, steel plate + PZT + elastomer layer. The aim of the paper is to illustrate the possibilities of using piezoelectric materials as an active control and elastomer layers as passive methods in one structure to improve the transmission loss.

PL

Artykuł przedstawia badania analityczne i symulacje oraz pomiary eksperymentalne inteligentnej struktury składającej się z płyty stalowej z przyklejonymi elementami aktywnymi PZT i naniesioną na powierzchnię warstwą elastomerową. Zbadano aktywne sterowanie promieniowaniem akustycznym płyty utwierdzonej na brzegach. Obliczenia numeryczne symulacji wykonano w środowisku obliczeniowym ANSYS. Obliczone zostały drgania i promieniowanie akustyczne płyty pod wpływem wymuszenia harmonicznego przez jeden z elementów PZT. Stanowisko pomiarowe usytuowano w zespole komór sprzężonych. Na stanowisku przetestowano kilka rodzajów obiektów badań: płyta stalowa z elementami PZT, płyta stalowa z warstwą elastomerową, płyta stalowa z elementami PZT i warstwą elastomerową. Celem artykułu jest pokazanie możliwości wykorzystania w jednej strukturze materiałów piezoelektrycznych, jako metody aktywnej i warstwy elastomerowej, jako metody pasywnej do zwiększenia dzwiękoizolacyjności struktury.

13

Active control of transient torsional vibrations due to run-up of a rotor machine driven by the electric motor

Szolc T., Jankowski Ł.

Vibrations in Physical Systems

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2008

|

Vol. 23

341--346

EN

In the paper active control of transient torsional vibrations induced by the electric motor during run-ups of the radial compressor drive system is performed by means of couplings with the magneto-rheological fluid. The main purpose of these studies is a minimisation of vibration amplitudes in order to increase the fatigue durability of the most responsible elements. The theoretical investigations are based on a hybrid structural model of the vibrating mechanical system and sensitivity analysis of the response with respect to the damping characteristics of the control couplings.

14

Polioptymalizacja sterowania aktywnym systemem zawieszenia siedziska ze względu na skuteczność izolacji i odporność układu

Maciejewski I.

Pomiary Automatyka Kontrola

|

2008

|

R. 54, nr 4

213-216

PL

Niniejsza praca dotyczy modelowania i symulacji komputerowej układu zawieszenia siedziska operatora maszyny roboczej. Prezentowane oblicze-nia analityczne i numeryczne obejmują problematykę związaną z ochroną operatora maszyny roboczej przed szkodliwym oddziaływaniem drgań mechanicznych. W pracy przedstawiono niedopasowanie własności wibrozolacyjnych siedzisk w przypadku zmiany parametrów pasywnego układu zawieszenia. W celu polepszenia ochrony operatorów opracowano system aktywny tłumienia drgań, który znacznie eliminuje wady konwencjonalnych układów. Dodatkowo zaprezentowano propozycję odpornego sterowania aktywnym systemem zawieszenia siedziska, w którym uwzględniono niepewności parametrów lepkosprężystego układu zawieszenia.

EN

The paper concerns modelling and computer simulation of the working machines seat suspension. The presented analytical and numerical calculations contain the problems of health protection of working machines operators against mechanical vibration. In the paper, the misfit of vibro-isolating properties of the seats in case of its parameters changing is shown. In order to improve protection of the operators, the active vibration control system is elaborated, which considerably eliminates the disadvantages of conventional systems. Additionally, the optimisation procedure of active suspension control robustness is proposed, with the use of uncertainties between nominal model and real object.

15

Active vibration reduction system with energy regeneration

Kowal J., Kot A.

Archives of Control Sciences

|

2007

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Vol. 17, no. 3

343-352

EN

Studies of the systems with energy regeneration have been carried out for years, since they primarily cover the assemblies with electrodynamic actuators. The paper addresses the issue of active reduction of mechanical vibration using DC motor as the actuator. Testing procedure is aimed to assess potential use of those assemblies in a different frequency band and force range than in electrodynamic actuators. The paper explains the operating principle of the system. The tested vibration reduction system is the physical model of 2 DOF suspension. Initial analysis has been conducted to explore the potential use of the energy produced by the vibration of sprung mass in the second degree of the suspension system in range of high frequencies, for power-supply to the active component incorporated in the same suspension degree in low frequencies range. Results of the experiments revealed that the mechanical parameters of the system can be selected in such a way that for specific interfering signals the accumulated energy should be at least equal to the energy used up by the system.

16

Active control of two degrees-of-freedom building-ground system

Awrejcewicz J., Olejnik P.

Archives of Control Sciences

|

2007

|

Vol. 17, no. 4

393-408

EN

The presented idea of active control of buildings is valid for the general concept of stabilization of some constructions subjected to an excitation coming, for instance, from earthquakes. The problem is analyzed in a two case studies describing not excited and externally loaded two degrees-of-freedom dynamical system. 2-DOF linear system is used to model the building-ground interactions. Algorithm that actively controls the system has been implemented and tested as well. The task finally reduces the investigations conducted in the work to estimation of the control force which could guarantee the sufficient minimization of the cost function proposed. On the basis of both analytical derivations and numerical analysis performed a few time histories of convergence of control force, components of the matrix of gain and accelerations of system masses have been illustrated and shortly described.

17

Some aspects of vibration control. Part II: An optimal active controller.

Kosowski K.

Polish Maritime Research

|

2005

|

nr 1

28-31

EN

The paper presents a theoretical method for determining the optimal correction to be introduced in a mechanical system. The active control of harmonic vibrations may be achived by applying a control unit which ought to reduce the vibration amplitude of the selected elements of the system. The proposed method makes it possible to determine the controller parameters which provide an optimum value of the chosen quality index. This criterion includes the reduction of weighted amplitudes of the elements on the one hand, and minimizes energy of the control signal on the other. The described method is suitable for determination of an optimum controller of turbine rotor vibrations caused by bearing oil whip, bearing oil whirl or aerodynamic forces. For the case of rotor self-excited vibrations of aerodynamic type the linear model of excitations was compared with the neural network method.

18

Active control of vibrations of a three-axis gyroscopic platform on board of a flying object

Koruba Z., Styczeń J.

Mechanics / AGH University of Science and Technology

|

2005

|

Vol. 24, no. 2

82-87

EN

The work presents an algorithm for active control of vibrations of a three-axis gyroscopic platform during pre-programmed and stabilised operation on board of a flying object. The considerations focus on disturbances resulting from the flying object manoeuvres and short-duration pulses of external forces under the conditions of friction in the bearings and non-linear platform operation range.

PL

W pracy przedstawiony jest algorytm aktywnego sterowania drganiami trzyosiowej platformy żyroskopowej przy jej ruchu programowym i stabilizującym na pokładzie obiektu latającego. Rozpatrywane są zakłócenia w postaci manewrów obiektu latającego (podstawy platformy) oraz krótkotrwałych impulsów sił zewnętrznych przy istnieniu tarcia w łożyskach i przy nieliniowym zakresie pracy rozważanej platformy.

19

Self balancing rotor design - simulation and experimental validation

Manka M., Uhl T.

Archives of Control Sciences

|

2005

|

Vol. 15, no. 2

233--247

EN

The paper deals with autimatic balancing of rotating systems during operation. After discussion of existing techniques the novel concepts of balancing mechanisms are presented. The proposed method are easy to apply to various rotating devices, with no need of machine construction modification. Next basics of active balancing control algorithms are presented, and designed detection and correction algorithms are discussed. After descriptions of mechanisms, measurement and control algorithms, simulation and experimental results are presented. The paper ands some conclusions about presented active balancing mechanisms and further works directions are presented.

20

Discrete air jets employed to control boundary layer separation.

Szumowski A., Wojciechowski J.

Archive of Mechanical Engineering

|

2005

|

Vol. LII, nr 2

207-215

EN

Turbulent boundary layer separation induced by positive pressure gradient at a plane surface is investigated experimentally. Separation is delayed by mean of a jet vortex generator in a form of small jets injected to the boundary layer of separation through orifices distributed across the main flow. The effect of jets intensity on delay of separation is examined. Swirled and non-swirled jets have been used. The energy of the air supplying the generator required to delay boundary layer separation is in the former case up to 40 % lower than in the later one.

PL

Na drodze eksperymentalnej badane jest oderwanie turbulentnej warstwy przyściennej na płaskiej powierzchni powodowane dodatnim gradientem ciśnienia. Oderwanie jest opóźniane w wyniku oddziaływania wiórów generowanych w warstwie przyściennej przez małe strumienie powietrza nadmuchiwane na ściankę. Rozpatrywane są strumienie proste (nie zawirowane) i zawirowane. W wyniku badań stwierdzono, że ten sam efekt opóźnienia oderwania można uzyskać przy ok. 40% mniejszym zużyciu energii w przypadku strumieni intensywnie zawirowanych w stosunku do strumieni prostych.