Mr Damper

Streszczenie
W artykule przedstawiono wyniki badań semiaktywnego układu redukcji drgań z odzyskiem energii, w którym elementem wykonawczym jest tłumik magnetoreologiczny (MR). Obiektem chronionym był model
pierwszej kondygnacji budowli pełniącej rolę kondygnacji izolującej od
drgań pozostałą część budowli. Badania przeprowadzono dla trzech przypadków zasilania cewki sterującej tłumika: napięciem bezpośrednio
z generatora, napięciem wyprostowanym przez mostek Graetz’a oraz
prądem o natężeniu sterowanym przez klucz analogowy znajdujący się na wyjściu mostka Graetz’a. Na podstawie przeprowadzonych badań wyznaczono charakterystyki układu. Charakterystyki te porównano z charakterystykami konwencjonalnego semiaktywnego układu redukcji z zewnętrznym źródłem zasilania.

Abstract
The paper summarizes the results of testing done on a semiactive vibration reduction system with energy recovery. The system uses a magnetorheological (MR) damper as an actuating element. The operating principle of the system involves the recovery of energy of the vibrating plant and converting it into electric energy (the velocity of the vibrating plant is converted into the electromotive force of induction, which generates the current flow in the control coil of the MR damper). Hence, the force generated by the MR damper is changed. Tests were done in the laboratory facility constructed for the purpose of the experimental program, incorporating a plant to be vibro-isolated, i.e. a mobile platform. The platform represents a model of the first floor in a building, which vibro-isolates the remaining part of the building. The vibration reduction system with energy recovery was tested in several configurations: when the control coil of the damper was voltagesupplied
directly from the generator or voltage-supplied via the Graetz bridge, or supplied with current controlled by an analogue switch, at the output from the Graetz bridge. The current-control system uses two feedback
loops. A sky-hook control algorithm is used in the external loop, whilst
the internal loop uses the algorithm switching the analogue switch. The
determined characteristics are compared with those obtained for a conventional semi-active vibration reduction system based on MR damper using an external power source.

Magnetorheological (MR) damper is one of the most advanced applications of semi active damper in controlling vibration. Due to its continuous controllability in both on and off state its practice is increasing day by day in the vehicle suspension system. MR damp-er’s damping force can be controlled by changing the viscosity of its internal magnetorheological fluids (MRF). But still there are some problems with this damper such as MR fluid’s sedimentation, optimal design configuration considering all components of the damper. In this paper both 2-D Axisymmetric and 3-D model of MR Damper is built and finite element analysis is done for design optimization. Different configurations of MR damper piston, MR fluid Gap, air gap and Dampers housing are simulated for compar-ing the Dampers performance variation. From the analytical results it is observed that among different configurations single coil MR damper with linear plastic air gap, top and bottom chamfered piston end and medium MR fluid gap shows better performance than other configurations by maintaining the same input current and piston velocity. Further an experimental analysis is performed by using RD-8041-1 MR Damper. These results are compared with the optimized MR Damper’s simulation results, which are clearly validating the simulated results.

Magneto-rheological (MR) dampers are semi-active control devices and use MR fluids. Magneto-rheological dampers have successful applications in mechatronics engineering, civil engineering and numerous areas of engineering. At present, traditional MR damper systems, require an isolated power supply and dynamic sensor, which requires large space. This paper presents the achievability and accuracy of a self-controlled, i.e., self-powered and self-sensing magneto-rheological damper using harvested energy from the vibration and shock environment in which it is deployed. Another important part of this paper is the increased yield stress of the Magneto-rheological Fluids. Magneto-rheological fluids that use replacement of glass beads for Magnetic Particles to surge yield stress is implemented here. Clearly this shows better result on yield stress, viscosity, and settling rate. The permanent magnet generator (PMG) is designed and attached to a MR damper. For evaluating the self-powered MR damper’s vibration mitigating capacity, an Engine Mount System using the MR damper is simulated with the help of ANSYS software. The ideal stiffness of the PMG for the Engine Mount System (EMS) is calculated by numerical study. The vibration mitigating performance of the EMS employing the self-powered & self-sensing MR damper is theoretically calculated and evaluated in the frequency domain.

In this paper an advanced semi-active damper is designed and experimentally studied to
investigate and establish its behavior. A prototype Magneto-rheological fluid Damper is designed as
advanced semi-active damper due to its huge advantages. Magneto-rheological fluid with improved
dispersion stability is prepared here as smart fluid. The relation between force and displacement for
various current has been established to develop the semi-active damper model. In this study a fuzzy
tuned PID controller is opted to achieve better response for a various frequency input. The proposed
MR damper can be applied to vehicle syspension system and other suspension mitigation system
widely. Moreover, the identified behavior can help in further development of MR damper
technology. The characteristics obtained from of MR damper is more realistic as it is obtained from
experiments.

This paper presents vibration control of a building model under earthquake loads. A magnetorheological (MR) damper is placed in the building between the first floor and ground for seismic response reduction. A new control algorithm to command the MR damper is proposed. The approach is inspired by a quasi-bang-bang controller; however, the proposed technique gives weights to control commands in a fashion that is similar to a fuzzy logic controller. Several control algorithms including decentralized bang-bang controller, Lyapunov controller, modulated homogeneous friction controller, maximum energy dissipation controller, and clipped-optimal controller are used for comparison. The new controller achieved the best reduction in maximum interstory drifts and maximum absolute accelerations over all the control algorithms presented. This reveals that the proposed controller with the MR damper is promising and may provide the best protection to the building and its contents.

This study concerns the modeling of the hysteretic behavior of magnetorheological (MR) dampers. In general, hysteresis is one of key factors influencing the output of such actuators. So far, more attention has been paid to studying the combined hysteretic behavior of MR actuators by observing the relationships between the output (force/torque) and the inputs (current, velocity, and position). However, these devices feature two distinct hysteretic mechanisms: mechanical/hydraulic and magnetic. The mechanical hysteresis is of different nature than the magnetic hysteresis due to the properties of ferromagnetic materials forming the actuator's electromagnet circuit, and these should be split in the modeling process. In the present study, we separate the magnetic hysteresis from the mechanical/hydraulic one by investigating the magnetic flux vs. exciting current relationship of a commercial flow-mode MR damper subjected to sinusoidal current loading and independently of the mechanical excitations. The resulting behavior of the electromagnetic circuit is then examined using the non-linear inductor approach with hysteresis. Total hysteresis is then modeled using a non-linear inductor model in combination with a phenomenological parametric Maxwell type model of the damper.

Magnetorheological (MR) damper is one of the most advanced applications of semi active damper in controlling vibration. Its use is increasing day by day in the vehicle suspension system due to its continuous controllability in both on and off state. MR damper’s damping force can be controlled by changing the viscosity of its internal magnetorheological fluids (MRF). Applying an external magnetic field viscosity of MRF can be controlled. Electromagnet such as solenoid coil is normally used as external magnetic field source. These coils are attached inside the damper’s piston head. When the damper operates these coils create heat. That’s why the conventional MR dampers normally face wide variations in temperature. This change of temperature results decay in MRF viscosity as well as post-yield damping of the damper. In this paper temperature effect on MR fluids viscosity and on MR dampers performance represented analytically and experimentally. Due to this temperature effect the deviation of MR dampers performance has shown here experimentally. Also a novel technique for solving the problem explained clearly.

ABSTRACT−In this paper, analytical characterization of the magneto-rheological (MR) damper is done using a new modified
algebraic model. Algebraic model is also more preferable because of its low computational expenses compared to differential
Bouc-Wen’s model which is highly computationally demanding. This model along with the obtained model parameters is used
as a semi-active suspension device in a quarter car model and the stationary response of the vehicle traversing on a rough road
is obtained. The control part consists of two nested controllers. One of them is the system controller which generates the
desired damping force and the other is the damper controller which adjusts the voltage level to MR damper so as to track the
desired damping force. For the system controller a model reference skyhook Sliding Mode Controller (SMC) is used and for
the damper controller a continuous state algorithm is built to determine the input voltage so as to gain the desired damping
force. The analytical model is subsequently used in the quarter car vehicle model and the vehicular responses are studied. A
simulation study is performed to prove the effectiveness and robustness of the semi-active control approach. Results show that
the semi-active controller can achieve compatible performance as that of active suspension controller except for a little
deterioration

The paper summarises the results of laboratory testing of an energy harvesting vibration reduction system based on a magne-torheological (MR) damper whose control circuit incorporates a battery of bipolar electrolytic capacitors (current cutoff 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 cutoff circuit results in a significant decrease of sprung mass vibration amplitudes when the frequency of acting excitation inputs is higher than the resonance frequency.

This study investigates the automotive magnetorheological (MR) shock absorber behaviour in conditions of changing temperature. Its temperature-dependent behaviour was quantified between ambient and maximal operating temperatures of the device. Aspects addressed include the temperature dependence of the control coil resistance in the absorber, the influence of operating current level on control coil temperature and the temperature dependence of the absorber force response and energy dissipation in the system. The results of experiments enabled us to evaluate the mechanical performance of the absorber at varied temperatures.

Magnetorheological (MR) damper is one of the advanced semi- active device that contains MR fluids. The damping force of this damper can be controlled by changing the viscosity of MR fluids. Current supplied to coils inside the piston creates magnetic field and works as the viscosity control mechanism. These coils consume a sufficient amount of electric power during magnetization process. A hybrid of permanent magnet and electric coils could be a good solution as permanent magnet requires a little electric power for magnetization process. MR damper has many mathematical modeling, but they didn’t consider the hybrid of Permanent magnet and electromagnet as magnetic circuit. In this study a new mathematical model has been developed by considering the effect of permanent magnet in the magnetic circuit. This model is also verified by MATLAB simulation by comparing with other conventional models and results are clearly verifying the performance improvement of the model.

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.

The study describes the laboratory stand for testing semi-active vibration reduction systems comprising a magnetorheological (MR) damper, powered from an electromagnetic generator. The design objectives, mechanical structure and parameters of the test stand are discussed. Dynamic parameters of the stand are estimated basing on numerical simulation data. The key elements of the test stand are presented: the vibration reduction system, the vibration generation system and the data acquisition system. Selected results of functional tests are provided.

Magnetorheological (MR) damper is one of the most advanced application of semi active devices. Its use is increasing day by day due to its huge advantages and wide range of application. The force delivered by MR damper can be varied by changing the viscosity of its internal MR fluids. Till now no details experimental analysis has been accomplished by considering various parameters. In this paper a brief experimental analysis has been investigated with the help of Universal Testing Machine to characterize MR damper. To characterize accurately MR damper has been analyzed experimentally for different stroke length, stroke rate, stroke mode. From the experimental results it is seen that the force delivered by MR damper has a proportional relation with input excitation current, stroke length and stroke rate.

The paper summarises the results of experimental testing of an electrical interface intended for use in the MR damper-based vibration reduction system with energy harvesting capability. The interface operation relies on the voltage resonance in the RLC circuit. The study investigates the interface structure and provides the discussion of experimental data.

ABSTRACT Magnetorheological (MR) fluid is a suspension of small iron particles, where, in the presence of a magnetic field, the solid particles arranged themselves as deformable chains. The deformation of the chain structure can be performed in three common modes known as flow mode, shear mode and squeeze mode. Among the three, the flow and shear modes have been widely investigated and used in commercial applications. Nevertheless, limited focus has been given to the combination of both modes. Furthermore, the existing combination between the flow and shear mode has been always defined at the same effective area, which is commonly known as the shear-flow mode. This paper provides a new perspective of mixed mode by arranging in series the different modes in the same MR cell. In order to manifest the theoretical model, an effective area representing the shear-flow mode is positioned separately with another effective area of the pure flow mode. The magnetic circuit design is validated by using the finite element method in 2D simulation. Moreover, the simulated results of magnetic flux density in the MR fluid are used to predict the force produced by the flow and shear-flow modes. The fabricated cell is tested under quasi-static loading and the results are compared with those that were predicted. It can be concluded that, to a certain extent, the obtained experimental results have been successfully predicted by the proposed model.

Magnetorheological (MR) fluid is a suspension of small iron particles, where, in the presence of a magnetic field, the solid particles arranged themselves as deformable chains. The deformation of the chain structure can be performed in three common modes known as flow mode, shear mode and squeeze mode. Among the three, the flow and shear modes have been widely investigated and used in commercial applications. Nevertheless, limited focus has been given to the combination of both modes. Furthermore, the existing combination between the flow and shear mode has been always defined at the same effective area, which is commonly known as the shear-flow mode. This paper provides a new perspective of mixed mode by arranging in series the different modes in the same MR cell. In order to manifest the theoretical model, an effective area representing the shear-flow mode is positioned separately with another effective area of the pure flow mode. The magnetic circuit design is validated by using ...

The design of a MR damper, consisting of piston and cylinder arrangement, is presented in this paper. In this paper, a 2D axisymmetric model based on finite element method (FEM) concept has been developed on the ANSYS platform to analyze and examine the MR damper characteristics. Based on the FEM model, a prototype of the MR damper is fabricated and tested experimentally in the semi active vibration laboratory of the department. The comparison of both these model analyses indicates that the FEM based model is effectively portraying the experimental behavior of the MR damper in terms of its damping force. The results obtained in this paper will be helpful for the designers to create more efficient and reliable MR dampers and also to predict its damping force characteristics.

Praca dotyczy modelowania samozasilającego się układu redukcji drgań z liniowym tłumikiem magnetoreologicznym (MR) dla obiektu o jednym stopniu swobody. Do modelowania przyjęto trzy modele tłumika MR (Binghama, opisany funkcjami hiperbolicznymi i Spencera), których parametry zależą od natężenia prądu w cewce sterującej tłumika. Modele zidentyfikowano na podstawie danych uzyskanych z badań laboratoryjnych tłumika RD-1005-3 firmy Lord Corporation. Posługując się tymi modelami oraz modelem generatora elektromagnetycznego, przeprowadzono symulacje komputerowe układu, wyznaczając charakterystyki przenoszenia drgań. Z porównania charakterystyk uzyskanych z obliczeń i z badań laboratoryjnych wynika, że najkorzystniejsze dopasowanie uzyskano, stosując model tłumika MR z funkcjami hiperbolicznymi. Model ten wykorzystano do symulacji samozasilającego się układu redukcji drgań, których celem było wyznaczenie jego podstawowych charakterystyk.

This research presents vibration control of buildings due to earthquake effect. The model is subjected to the horizontal component of the earthquake, which has a larger effect than the vertical component. Newton's second law of motion is applied to obtain the mathematical model of the structures. Magneto-Rheological (MR) dampers are placed between the stories. Several control algorithms including the decentralized bang-bang controller, the Lyapunov controller, the modulated homogeneous friction controller, the maximum energy dissipation controller, and the clipped-optimal controller are applied with the MR damper. The modified quasi-bang-bang control is proposed in this paper. The MR damper (depending on the control algorithm used) gives a better reduction in the maximum absolute acceleration, also an excellent reduction in the maximum inter-story displacement; also the maximum displacement of the top story is reduced.