Modeling Of Magnetorheological Fluid Damper Research Articles

Vibration control of primary and subharmonic simultaneous resonance of nonlinear system with fractional-order Bingham model

The passive vibration control of primary and subharmonic simultaneous resonance for the Duffing-type nonlinear system under the base excitation and external excitation by using magnetorheological (MR) fluid damper is studied, where the fractional-order derivative Bingham model of MR fluid damper is considered. The approximate analytical solution of the system is obtained by using the incremental averaging method. On the basis of obtaining the primary resonance of the system under base excitation by the averaging method, the subharmonic resonance solution of the system is obtained by taking the subharmonic resonance of the system under base excitation and external excitation as an increment, so as to obtain the approximate analytical solution of the simultaneous resonance of primary and subharmonic resonance. And the amplitude–frequency equation and phase–frequency equation of the steady-state solutions for the primary and subharmonic resonance of the system are derived respectively. According to the approximate analytical solutions, the stability conditions of the steady-state solution of the primary resonance and subharmonic simultaneous resonance are obtained by Lyapunov method. Compared with the numerical solution, the correctness and accuracy of the analytical solution of the primary resonance and subharmonic simultaneous resonance are demonstrated. The influence of system parameters on the resonant response of the system is analyzed in detail, with emphasis on the resonance bifurcation behavior of the system. The analysis results show that the damping passive vibration reduction control has obvious vibration suppression effect on the primary and subharmonic simultaneous resonance of the Duffing-type nonlinear system. Under certain conditions, there are 9 branches in the steady-state amplitude–frequency response of the primary and subharmonic simultaneous resonance of the Duffing-type system, of which 5 branches are stable solutions.

COMBINED CONTROL OF VEHICLE SUSPENSION WITH FRACTIONAL-ORDER MAGNETORHEOLOGICAL FLUID DAMPER MODEL

The fractional-order Bingham model of magnetorheological fluid damper has simple structure and can better describe the hysteretic characteristics of the system. The vibration control of a nonlinear vehicle suspension system with magnetorheological fluid damper under harmonic excitation is studied, where the single-degree-of-freedom 1/4 vehicle suspension system with fractional-order Bingham model of magnetorheological fluid damper is considered. The primary resonance response of suspension system with fractional-order Bingham model under sky-hook damping semi-active control is analyzed, and the approximate analytical solution is obtained by means of averaging method. The amplitude-frequency response equation of the steady-state solution of the suspension system is obtained, and the stability condition of the suspension system is also obtained according to Lyapunov’s stability theory. By comparing the amplitude-frequency response curves of the numerical solution and approximate analytical solution, the accuracy of the approximate analytical solution has been verified. The influence of semi-active control on the ride comfort of the vehicle is illustrated by the root mean square values of acceleration of the sprung mass in the vertical direction, it is found that the semi-active control strategy of sky-hook damping can not improve the ride comfort of vehicle in low frequency excitation region of road. Therefore, a combined control strategy of passive control and semi-active control is proposed, and the influence of semi-active control parameter on the vibration control effect is analyzed. The results show that the combined control strategy can not only improve the ride comfort of the vehicle, but also effectively suppress the primary resonance vibration amplitude of suspension system.

Optimized Fuzzy Skyhook Control for Semi-Active Vehicle Suspension with New Inverse Model of Magnetorheological Fluid Damper

To improve the performance of vehicle suspension, this paper proposes a semi-active vehicle suspension with a magnetorheological fluid (MRF) damper. We designed an optimized fuzzy skyhook controller with grey wolf optimizer (GWO) algorithm base on a new neuro-inverse model of the MRF damper. Because the inverse model of the MRF damper is difficult to establish directly, the Elman neural network was applied. The novelty of this study is the application of the new inverse model for semi-active vibration control and optimization of the semi-active suspension control method. The calculation results showed that the new inverse model can accurately calculate the required control current. The fuzzy skyhook control method optimized by the grey wolf optimizer (GWO) algorithm was established based on the inverse model to control the suspension vibration. The simulation results showed that the optimized fuzzy skyhook control method can simultaneously reduce the amplitude of vertical acceleration, suspension deflection, and tire dynamic load.

Exact physical model of magnetorheological damper

• We propose a novel, enhanced physical model of magnetorheological fluid damper. • The model combines compressibility of the fluid and blocking of the flow. • This effect provides distinctive ``z-shaped'' force–velocity hysteresis loops. • We propose reduced and parametric models with analytical form of generated force. • The numerical hysteretic loops are in good agreement with experimental data. This paper attempts to fill the gap in the literature by introducing and discussing an enhanced physical model of the MR damper. The essence of the presented model is to combine the effect of compressibility of the MR fluid enclosed in each chamber with the effect of blocking the flow between the chambers in the case of a low pressure difference. As it will be shown, the concurrence of both considered phenomena significantly affects mechanical behaviour of the damper, influences its dissipative characteristics, and in particular, it is the reason behind the distinctive ‘z-shaped’ force–velocity hysteresis loops observed in experiments. The paper presents explanation of the observed phenomena, detailed derivation of the thermodynamic equations governing response of the damper, their implementation for various constitutive models of the magnetorheological fluid and, finally, formulation of the corresponding reduced and parametric models. Experimental validation shows that proper identification of physical parameters of the proposed mathematical model yields the correct shapes of force–velocity hysteresis loops.

Adaptive semi-parallel position/force-sensorless control of electro-hydraulic actuator system using MR fluid damper

The focus of this paper is to develop a semi-parallel control method using an inversion of identification model of a magnetorheological (MR) fluid damper along with a smart predictor controller (SPC) for a damping system using that damper and an electrohydraulic actuator (EHA) in order to realize the real time position/force control of the industrial task requiring interaction with the environment. The inverse model of MR fluid damper is established base on a self-tuning Lyapunov-based fuzzy (STLF) model. This STLF model is designed in the form of a center average fuzzy interference system, of which the fuzzy rules are planted based on the Lyapunov stability condition. In addition, in order to optimize the STLF model, the back propagation learning rules are used to adjust the fuzzy weighting net. Meanwhile, the SPC is constructed using a nonlinear PID controller (NPID) base on feedforward neural network and a smart Grey-Markov predictor (SGMP). Here, the NPID controller is built to drive the system to desired targets. Additionally, a learning mechanism with robust checking conditions is implemented into the NPID in order to optimize online its parameters with respect to the control error minimization. Besides, the SGMP with self-tuning ability of the predictor step size takes part in, first, estimating the system.

Hysteresis modeling of magneto-rheological damper using self-tuning Lyapunov-based fuzzy approach

Magneto-rheological (MR) fluid damper is a semi-active control device that has recently received more attention because they offer the adaptability of active control devices without requiring the associated large power sources. But inherent nonlinear nature of the MR fluid damper is one of the challenging aspects for utilizing this device to achieve the high performance. So development of an accurate MR fluid damper model is necessary to take the advantages from its unique characteristics. The focus of this paper is to develop an alternative method for modeling a MR fluid damper by using a so-called self-tuning Lyapunov-based fuzzy model (STLFM). Here, the model is constructed in the form of a center average fuzzy interference system, of which the fuzzy rules are designed based on the Lyapunov stability condition. In addition, in order to optimize the STLFM, the back propagation learning rules are used to adjust the fuzzy weighting net. Firstly, experimental data of a damping system using this damper is used to optimize the model. Next, the optimized model is used to estimate online the damping performance in the real-time conditions. The modeling results prove convincingly that the developed model could represent satisfactorily the behavior of the MR fluid damper.

Dissipativity analysis of the base isolated benchmark structure with magnetorheologicalfluid dampers

This paper investigates the dissipativity and performance characteristics of the semiactivecontrol of the base isolated benchmark structure with magnetorheological (MR) fluiddampers. Previously, the authors introduced the concepts of dissipativity and dissipativityindices in the semiactive control of structures with smart dampers and studied thedissipativity characteristics of simple structures with idealized dampers. To investigate theeffects of semiactive controller dissipativity characteristics on the overall performance of thebase isolated benchmark building, a clipped optimal control strategy with a linearquadratic Gaussian (LQG) controller and a 20 ton MR fluid damper model is used.A cumulative index is proposed for quantifying the overall dissipativity of a control systemwith multiple control devices. Two control designs with different dissipativity andperformance characteristics are considered as the primary controller in clipped optimalcontrol. Numerical simulations reveal that the dissipativity indices can be classifiedinto two groups that exhibit distinct patterns. It is shown that the dissipativityindices identify primary controllers that are more suitable for application withMR dampers and provide useful information in the semiactive design processthat complements other performance indices. The computational efficiency ofthe proposed dissipativity indices is verified by comparing computation times.

An innovative magnetorheological damper for automotive suspension: from design toexperimental characterization

The development of a powerful new magnetorheological fluid (MRF), together with recentprogress in the understanding of the behavior of such fluids, has convinced researchers andengineers that MRF dampers are among the most promising devices for semi-activeautomotive suspension vibration control, because of their large force capacity and theirinherent ability to provide a simple, fast and robust interface between electronic controlsand mechanical components.In this paper, theoretical and experimental studies are performed for the design,development and testing of a completely new MRF damper model that can be used for thesemi-active control of automotive suspensions. The MR damper technology presented inthis paper is based on a completely new approach where, in contrast to in theconventional solutions where the coil axis is usually superposed on the damper axis andwhere the inner cylindrical housing is part of the magnetic circuit, the coils arewound in a direction perpendicular to the damper axis. The paper investigatesapproaches to optimizing the dynamic response and provides experimental verification.Both experimental and theoretical results have shown that, if this particular model isfilled with an ‘MRF 336AG’ MR fluid, it can provide large controllable dampingforces that require only a small amount of energy. For a magnetizing system withfour coils, the damping coefficient could be increased by up to three times for anexcitation current of only 2 A. Such current could be reduced to less than 1 A if themagnetizing system used eight small cores. In this case, the magnetic field willbe more powerful and more regularly distributed. In the presence of harmonicexcitation, such a design will allow the optimum compromise between comfortand stability to be reached over different intervals of the excitation frequencies.

Semi-active control of automotive suspension systems with magneto-rheological dampers

This paper is aimed to develop semi-active control for automotive suspension systems with magneto-rheological (MR) fluid dampers. A two degree-of-freedom quarter car model is considered. A mathematical model of MR fluid damper is adopted. In this study, there are two nested controllers including system controller and damper controller. For the system controller, a model-reference sliding mode controller is developed for considering loading uncertainty to result in a robust control system. In order to choose a good reference model, the single-degree-of-freedom skyhook system is analysed. For the damper controller, the continuous-state control is used to track the actual damping force to the desired damping force. The transmissibilities of the MR suspension system are investigated. The performances of the MR suspension systems are evaluated by computer simulation with bump and random excitations. The effectiveness of the MR suspension system is also demonstrated via hardware-in-the-loop simulation (HILS) with sinusoidal excitation.