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EN
The newly developed ideal rectifier bridge equipped with four N-type MOSFETs and two rail-to-rail operational amplifiers is a part of a typical energy harvesting conditioning circuit responsible for the rectification stage in the system of converting the energy harvested from vibrations into electrical energy to power the MR damper. The only energy loss in the bridge is caused by the voltage loss in transistors’ channels. The first sections of the work summarises the structural design of the bridge, the simulation procedure under the RL load and by sine voltage inputs with predetermined frequency and amplitude range, and benchmarks the results against those obtained for the conventional bridge based on Schottky diodes. In the second section, the PCB prototype of the bridge is analysed, and measurement data are compiled. The third section reports on the laboratory testing of the developed bridge converting the harvested energy in an MR damper-based vibration reduction system.
EN
In this paper, the modelling process and control strategy of a semi-active seat suspension with a magneto-rheological damper (MR) is presented. The proposed system should protect operators of working machines against vibration in the horizontal direction. The control algorithm mimics the desired force that might be introduced into the seat suspension actively. The model parameters are determined experimentally as a function of the control current. The elaborated system is tested by using an electro-hydraulic shaker that generates vibrations for the semi-active seat suspension with the seated human body. Power spectral densities and transmissibility functions are presented as the results of simulations and measurements. In addition, transmissibility factors and maximum relative displacements of the suspension are evaluated for both the conventional passive seat suspension and the semi-active system with an MR damper.
EN
The study investigates the self-sensing ability in an energy harvesting magnetorheological damper (EHMRD). The device consists of a conventional linear MR damper and an electromagnetic harvester. The objective of the work is to demonstrate that the EHMRD with specific self-powered feature can also serve as a velocity sensor. Main components of the device and design structure are summarized and its operation principle is highlighted. The diagram of the experimental set-up incorporating the measurement and processing unit is provided, the experimental procedure is outlined and data processing is discussed. The self-sensing function is proposed whereby the relative velocity of the EHMRD can be reconstructed from the electromotive force (emf) induced in the harvester coil. To demonstrate the adequacy of the self-sensing action (i.e., the induced emf should agree well with the relative velocity), the proposed self-sensing function is implemented and tested in the embedded system that will be a target control platform. Finally, the test results of the system utilizing a switching control algorithm are provided to demonstrate the potentials of the EHMRD acting as a velocity sensor and to confirm its applicability in semi-active vibration control systems.
4
Content available remote Prototyping an MR damper system
EN
Magnetorheological (MR) shock absorbers are semi-active devices based on smart fluids. The fluid when exposed to magnetic field undergoes a transition from a liquid to a pseudo-solid. The change is reversible and fast and it has made the material attractive for use in semi-active real-time systems for vibration reduction. At the same time designing a shock absorber is a complex process due to the multi-physics involved. In this paper the author shows an approach that can be used for virtual prototyping studies of MR flow-mode devices. Magnetostatic calculations are followed by time-harmonics analyses of the circuit of the valve. The analysis is then complemented by a parametric study of the controller-damper system subjected to regulated (commanded) current step inputs using a lumped parameter model of the MR valve.
PL
Tłumiki magnetoreologiczne (MR) należą do grupy semi-aktywnych urządzeń wykorzystującyc tzw. ciecze inteligentne. Ciecz magnetoreologiczna jest zawiesiną cząstek ferromagnetycznych I nalezy do grupy materiałów o sterowalnych właściwościach reologicznych. Ciecz MR umieszczona w polu magnetycznym zmianie zmienia lepkość pozorną. Zmiana ta jest szybka i odwracalna, a końcowy stan materiału zależy od natężenia pola magnetycznego. Dzięki temu materiały te znalazły zastosowanie w semi-aktywnych układach redukcji drgań. Zaprojektowanie tłumika MR o odpowiednich osiągach jest jednak zadaniem złożonym. W niniejszym artykule autor przedstawia koncepcję budowy modelu systemu MR obejmującego tłumik i regulator PWM. Na wybranym przykładzie przedstawiono wyniki obliczeń polowych magnetostatycznych i harmonicznych obwodu tłumika. Wyniki obliczeń posłużyły m.in. do budowy modelu obwodu sterującego tłumika o parametrach skupionych z regulatorem.
PL
W pracy przeprowadzono analizę harvestera działającego w oparciu o zjawisko Faradaya, który będzie wykorzystany do zasilania liniowego tłumika magnetoreologicznego (MR). Opisano budowę harvestera, podając jego parametry geometryczne i magnetyczne. Przedstawiono wyniki obliczeń numerycznych harvestera dla dwóch wariantów połączeń uzwojenia cewki. Wyznaczono rozkład indukcji magnetycznej i siłę zaczepową w harvesterze oraz przeanalizowano jego działanie w stanie jałowym i w stanie obciążenia cewką sterującą tłumika MR. Zwrócono uwagę na możliwość pracy harvestera jako czujnika prędkości.
EN
This study investigates the performance of an energy harvester, utilizing the Faraday's law, used to supply a linear magnetorheological (MR) damper. The structural design of the harvester is outlined and its geometrical and magnetic parameters are summarised. The numerical calculation data were obtained for two variants of coil winding connections. Distribution of magnetic flux density and the cogging force are obtained both under the idle run and under the load applied to the control coil of the MR damper. It is demonstrated that the harvester can be operated as a velocity sensor.
6
Content available remote Vibration Control of a Seat Suspension System by Using Magnetorheological Damper
EN
In this paper, the modelling process and control strategy of the semi-active seat suspension with magneto-rheological damper (MR) is presented. The proposed system should protect the working machines operators against vibration in horizontal direction. The control algorithm mimics the desired force that might be actively introduced into the seat suspension. The model parameters are determined experimentally as a function of the control current. The elaborated system is tested by using the electro-hydraulic shaker that generates vibrations of the semi-active seat suspension with seated human body. The power spectral densities and the transmissibility functions are presented as the results of simulations and measurements. In addition, the transmissibility factors and the maximum relative displacements of suspension are evaluated for both the conventional passive seat suspension and the semi-active system with MR damper.
EN
The paper is devoted to the analysis and research of the possibility of adapting magnetorheological damper to minimize the unfavorable dynamic phenomena affecting the shooter when firing from a hunting shotgun. A design and construction of a so-called “smart” device is discussed. The damper was installed inside a modified shotgun stock, and used to reduce the value of recoil force acting on the shooter’s shoulder. The proposed solution minimizes the recoil, increases the comfort of use of the weapon and consequently improves the accuracy. The effectiveness of the solution has been verified experimentally.
EN
The paper summarises the results of laboratory testing of an energy harvesting vibration reduction system based on a magnetorheological (MR) damper whose control circuit incorporates a battery of bipolar electrolytic capacitors (current cut-off circuit). It is designed to reduce the undesired effects in vibration reduction systems of this type, associated with the increasing amplitude of the sprung mass vibration under the excitation inputs whose frequency should exceed the resonance frequency of the entire system. Results have demonstrated that incorporating a current cut-off circuit results in a significant decrease of sprung mass vibration amplitudes when the frequency of acting excitation inputs is higher than the resonance frequency.
PL
W artykule przedstawiono wyniki analizy numerycznej elektromagnetycznego przetwornika energii przeznaczonego do zasilania obrotowego tłumika magnetoreologicznego (MR). Opisano budowę i działanie przetwornika. Wyznaczono rozkład indukcji pola magnetycznego w przetworniku i siłę elektromotoryczną indukowaną w jego uzwojeniu. Obliczono przebiegi czasowe napięcia, prądu i mocy chwilowej w obwodzie zakładając, że cewka sterująca tłumika MR jest reprezentowana przez dwójnik RL. Wyznaczono zależności prądu i mocy przetwornika od prędkości obrotowej. Wyniki analiz numerycznych potwierdzono przeprowadzając badania doświadczalne przetwornika.
EN
The article presents a numerical analysis of an electromagnetic energy converter designed to power a magnetorheological damper (MR). It describes the construction and the operation of the converter. The distribution of the magnetic field in the transducer and the electromotive force induced in its coil were determined. The time patterns of voltage, current and instantaneous power in the circuit were calculated assuming that the control coil of the MR damper was represented by a two-terminal circuit RL. Moreover, the current and the power of the transducer were determined versus the rotary speed. Numerical results were confirmed in the simulations the experimental tests.
EN
The study investigates the performance of a semi-active vehicle engine mount incorporating an MR damper working in the squeeze mode (MRSQD), summarising its design, operating principles and key characteristics. The mathematical model of the mount is formulated based on the newly developed MRSQD. Two control algorithms are proposed for MRSQD control. The first algorithm (ALG1) uses the inverse model of the engine-frame system, the other is the sliding mode algorithm (ALG2). The effectiveness of the engine mount system is demonstrated in computer simulation.
EN
The study summarises the results of experimental examination of velocity sensing capability in a prototype of a magnetorheological damper with power generation (MRD). The device has two main components: an electromagnetic power generator and an MR damper. The study outlines the structure of the device with the main focus on the generator part, and provides results of tests performed under the idle run. The discussion of demonstrates the potentials of MRD action as a velocity-sign sensor and presents key issues which need to be addressed to enable its real life applications.
EN
A physical model of a vehicle engine mount incorporating a magnetorheological (MR) damper in squeeze mode is investigated and the structural design and operating characteristics of the MR damper are provided. The mathematical model of an engine mount is formulated. Kinematic excitations are assumed to be those emulating road profile-chassis (car body) interactions. Simulations of engine vibration are performed to determine the efficiency of the proposed engine mount. Conclusions are drawn concerning the potential applications of the MR damper in vehicle engine mounts.
PL
W pracy opisano budowę modelu fizycznego zawieszenia silnika samochodowego, w którym zastosowano tłumik z cieczą magnetoreologiczną (MR) działającą w trybie ściskania. Sformułowano model matematyczny zawieszenia. Zakładając wymuszenie kinematyczne modelujące oddziaływanie nierówności drogi na karoserią, przeprowadzono symulacje komputerowe drgań silnika. Oceniono efektywność działania zawieszenia oraz sformułowano wnioski dotyczące możliwości zastosowania tłumika MR w zawieszeniu silnika samochodowego.
EN
Vibration of a wind turbine tower is related to fatigue wear, influencing reliability of the whole structure. The current paper deals with the problem of Linear-Quadratic-Gaussian (LQG) tower vibration control using specially designed and built simulation and laboratory tower-nacelle models with a horizontally aligned, magnetorheological (MR) damper based tuned vibration absorber located at the nacelle. Force excitation applied horizontally to the tower itself, or to the nacelle, is considered. The MR damper LQG control algorithm, including the Kalman state observer and LQR (Linear-Quadratic-Regulator) controller is analysed numerically and implemented on the laboratory ground, in comparison with the system with a deactivated absorber. Simulation and experimental results are presented.
EN
The study investigates an energy harvesting system utilising rotary motion. The system has three components: a rotary MR damper to vary the damping characteristics, a rotary power generator (energy extractor) producing electrical power, and a conditioning electronics unit to interface directly with the damper and the generator. The objective of the study is to examine the system performance through experiments. The paper outlines the structure of the damper and the generator, provides selected results of examination of the system components and the whole system under idle run and under load for the assumed speed range. The results demonstrate that the system is adaptable to external excitations, does not require an extra power supply and provides a smart solution with potential applications to rotary motion control.
EN
The paper deals with an MR damper-based vibration reduction system with energy harvesting capability. The main part of the system creates an MR damper and a power generator based on an electromagnetic transduction mechanism, which are integrated into a stand- -alone device (so called energy harvesting MR damper). The main objective of the work is to evaluate performance of the proposed vibration reduction system employed in a single DOF mechanical structure. The material outlines the design structure and characteristics of the energy harvesting MR damper, presents the vibration reduction system based on this damper and explores experimental testing of the system implemented in a single DOF mechanical structure. To demonstrate that the devised system is feasible, performance figures maps completed by experimental data are shown.
EN
Wind turbine tower dynamic stress is related to the fatigue wear and reliability of the whole wind turbine structure. This paper deals with the problem of tower vibration control using a specially designed and built laboratory model. The considered wind turbine tower-nacelle model consists of a vertically arranged stiff rod (representing the tower), and a system of steel plates (representing nacelle and turbine assemblies) fixed at its top. The horizontally aligned tuned vibration absorber (TVA) with magnetorheological (MR) damper is located also at the top of the rod (in nacelle system). Force excitation sources applied horizontally to the tower itself and to the nacelle were both considered. The MR damper real-time control algorithms, including ground hook control and its modification, sliding mode control, linear and nonlinear (cubic and square root) damping, and adaptive solutions are compared to the open-loop case with various constant MR damper input current values and system without MR TVA (i.e., MR TVA in “locked” state). Comprehensive experimental analyses and their results are presented.
EN
The study investigates the behaviour of an electrical interface incorporated in a MR damper-based vibration reduction system powered with energy recovered from vibration. The interface, comprising the R, L and C elements, is connected in between the coil in an electromagnetic electric generator and the control coil in the MR damper and its function is to convert the output voltage from the generator. The interface model was formulated and computer simulations were performed to find out how the parameters of the interface should influence the frequency responses of the vibration reduction system.
18
PL
W pracy opisano wyniki symulacji numerycznych obwodu sterującego tłumika z cieczą MR działającą w trybie ściskania. Określono wpływ wysokości szczeliny roboczej i prądu na strumień magnetyczny skojarzony z obwodem sterujacym. Zakładając harmoniczny ruch tłoka, obliczono prąd w obwodzie sterującym przy zasilaniu napięciem stałym i danych wysokościach szczeliny roboczej. Wyznaczono przykładowe charaterystyki tłumika, przedstawiające zależność wytwarzanej siły od wysokości szczeliny roboczej dla przyjetych wartości prądu.
EN
The paper summarises the results of numerical simulations of a control circuit for an MR damper operated in squeeze mode. The influence of the control gap height and current level on magnetic flux linkage was established. Assuming the piston motion to be harmonic, the current in the control circuit was computed under the constant-voltage supply conditions and for the specified gap heights. Damper force vs gap height plots obtained for the specified current levels are provided as an example of damper characteristics.
PL
W pracy przeprowadzono obliczenia polowe nowej konstrukcji tłumika z cieczą MR działającą w trybie ściskania. Wyznaczono rozkład indukcji magnetycznej w tłumiku, zależność składowej osiowej indukcji od promienia szczeliny roboczej oraz zależność średniej wartości modułu indukcji i siły oddziaływania magnetycznego w komorze kompensacyjnej od wysokości szczeliny roboczej.
EN
Calculations were performed to find the field parameters of a new-design MR damper operated in the squeeze mode: distribution of magnetic field density in the damper, the relationship between the axial component of induction and the gap radius and the relationship between the average value of induction modulus, and the magnetic interaction force inside the compensation unit and the gap height.
20
PL
W pracy przedstawiono wyniki symulacji numerycznych zjawisk elektromagnetycznych zachodzących w tłumiku z cieczą MR działającą w trybie ściskania. Wyznaczono rozkład pola magnetycznego w tłumiku, zależność składowej osiowej indukcji magnetycznej i indukcyjności cewki sterującej od wysokości szczeliny roboczej, rozkład gęstości mocy strat wiroprądowych oraz siłę zaczepową.
EN
The paper summarises the results of numerical simulations of electromagnetic phenomena in an MR damper operated in squeeze mode. Cognisance is taken of the magnetic field distribution and the relationship is found between the axial component of magnetic induction and inductance of the control coil and the gap height. The power spectral density of losses due to eddy currents and the cogging force are determined, too.
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