Semi-active Magnetorheological Damper Research Articles

A genetic algorithm–based design approach for smart base isolation systems

This article presents a new approach for designing effective smart base isolation systems composed of a low-damping linear base isolation and a semi-active magneto-rheological damper. The method is based on transforming the design procedure of the hybrid base isolation system into a constrained optimization problem. The magneto-rheological damper command voltages have been determined using H2/linear quadratic Gaussian and clipped-optimal control algorithms. Through a sensitivity analysis to identify the effective design parameters, base isolation and control algorithm parameters have been taken as design variables and optimally determined using genetic algorithm. To restrict increases in floor accelerations, the objective function of the optimization problem has been defined as minimizing the maximum base drift while putting specific constraint on the acceleration response. For illustration, the proposed method has been applied to design a semi-active hybrid isolation system for a four-story shear building under earthquake excitation. The results of numerical simulations show the effectiveness, simplicity, and capability of the proposed method. Furthermore, it has been shown that using the proposed method, the acceleration of the isolated structure can also be incorporated into design process and practically controlled with a slight sacrifice of control effectiveness in reducing the base drift.

Modelling and simulation of the dynamic performance of a no-till seeding assembly with a semi-active damper

In no-till seeding, one of the biggest challenges to achieve a reliable seed germination and an even plant field emergence is an extreme variation in the desired seeding depth. This is caused by the inadequate response of the seeder motion dynamics to harsh soil conditions and to high operating speeds. In order to assess and optimise the dynamic response of a no-till seeder, mathematical models were developed for simulating the vertical motion of a coulter assembly. The models included the dynamics of the coulter assembly, with the packer wheel as a passive system, and a semi-active MR (magnetorheological) damper system, which was considered to be located in-between the coulter and the packer wheel. The developed model of the coulter assembly dynamics was validated based on a correlation between the simulated and the measured impact forces and pitch angles. A root-mean-squared (RMS) error resulted from the correlation have increased from 6.84% at the lower speed of 10kmh−1 to 14.5% at the higher speed of 15kmh−1 for the impact forces, from 8.1% at the lower speed of 10kmh−1 to 13.1% at the higher speed of 15kmh−1 for the pitch angle. Conversely, there was a fall in the correlation coefficient from 0.699 to 0.681 for the impact forces and from 0.942 to 0.684 for the pitch angle between the lower speed of 10kmh−1 and the higher speed of 15kmh−1, respectively. Furthermore, all three applied hysteresis models, such as Bingham, Dahl and Bounc-Wen model, for the semi-active MR damper system behaviour demonstrated significant improvements over the passive system model. Among the models, the Bouc-Wen model produced more adequacy of the MR damper behaviour with the highest reduction of 54.1%, 63.3% and 41.2% in the amplitude of the impact forces and 52.3%, 58.2% and 38.1% in the amplitude of the pitch angles at the speeds of 10kmh−1, 12kmh−1 and 15kmh−1, respectively.

Vertical vibration control of suspension bridges subjected to earthquake by Semi-active MR dampers

In this paper, a semi-active control technique is presented to mitigate the seismic vertical response of suspension bridges using magneto-rheological (MR) dampers. MR dampers, as semi-active control devices, have received significant attention in recent years because of their adaptability of working as active control devices without requiring large power of sources. The most challenging problem in this study is that: how to install the dampers at the degrees along the bridge span far from the towers? In the present paper, to solve this problem, a rigid truss which is attached to the bottom of the bridge deck is proposed. The MR damper can be installed between the bridge deck and free-end of the truss. For numerical study, the Vincent-Thomas suspension bridge is chosen and different schemes, in point of number and location of the dampers view, have been proposed to get optimal performance of the dampers in reducing the bridge vertical responses. To reach this goal, all of the schemes are optimized, as well as the controlled and uncontrolled responses of the bridge are calculated under application of 15 major world-wide earthquake accelerogrames. The results indicate that the proposed models can effectively reduce the vertical responses of the example bridge.

Novel fuzzy sliding controller for MRD suspensions subjected to uncertainty and disturbance

In this paper, the design of an adaptive optimal fuzzy sliding controller (AOFSC) for semi-active magnetorheological damper (MRD) vehicle suspension system subjected to uncertainty and disturbance (UAD) whose time-varying rate may be high but bounded is presented. This is a combination of an adaptive optimal fuzzy sliding mode controller (FSMCop), a nonlinear disturbance observer (NDO) and an inverse MRD model to create the desired control force, including the compensation part for UAD. An adaptive control law is proposed to establish a fuzzy-gain update law for the AOFSC and a parameter tie for the NDO such that the convergence of system's dynamic response is a Lyapunov asymptotically stable process. Surveys via simulations along with via an experimental apparatus showed that the high capability to exterminate vibration, robust stability, and the economic efficiency are the main advantages of the proposed AOFSC.

Semi-active Outrigger Damping System for Seismic Protection of Building Structure

The outrigger structural system is one of the most widely used lateral load-resisting structural systems for high-rise buildings. To increase the energy dissipation capacity of the outrigger system, an outrigger damping system has been proposed as a novel energy dissipation system. In this system, the outrigger and perimeter columns are separate and vertical viscous dampers are equipped between the outrigger and perimeter columns. In this study, the control performance of a semi-active outrigger damping system for the seismic protection of a building structure was investigated. Semi-active damping devices, such as magnetorheological (MR) dampers instead of passive dampers, are installed vertically between the outrigger and perimeter columns to achieve large and adaptable energy dissipation. A fuzzy logic control algorithm was used to generate a command voltage sent to the semi-active MR dampers. A genetic algorithm was used to optimize the fuzzy logic controller. An artificial earthquake load was generated for the numerical simulation and a simplified numerical model of a damped outrigger system was developed. Numerical analyses showed that the semi-active damped outrigger system could effectively reduce both the displacement and acceleration responses of the tall buildings compared to a passive outrigger damper system.

A new adaptive sliding mode control for Macpherson strut suspension system with magneto-rheological damper

This work proposes a new adaptive sliding mode controller to enhance ride comfort and steering stability of automobile associated with a semi-active magneto-rheological damper. In this study, a Macpherson strut type suspension system which is widely used in light vehicles is considered. The dynamic model of the Macpherson strut with magneto-rheological damper is obtained and the governing equations are then formulated using kinematic properties of the suspension system following Lagrange’s formulation. In the formulation of the model, both the rotation of the wheel assembly and the lateral stiffness of the tire are considered to represent the nonlinear characteristic of Macpherson type suspension system. Subsequently, in order to effectively reduce unwanted vibrations, a new adaptive sliding mode controller is designed by adopting moving sliding surface instead of conventional fixed sliding surface. In order to demonstrate the effectiveness of the proposed controller, a cylindrical magneto-rheological damper is designed and manufactured on the basis of practical application conditions such as required damping force. Then, ride comfort, suspension travel, and road handling are evaluated and some benefits of the proposed controller such as enhanced ride comfort are evaluated.

Time delay study for semi-active control of coupled adjacent structures using MR damper

The pounding phenomenon in adjacent structures happens in severing earthquakes that can cause great damages. Connecting neighboring structures with active and semi-active control devices is an effective method to avoid mutual colliding between neighboring buildings. One of the most important issues in control systems is applying online control force. There will be a time delay if the prose of producing control force does not perform on time. This paper proposed a time-delay compensation method in coupled structures control, with semi-active Magnetorheological (MR) damper. This method based on Newmark's integration is adopted to mitigate the time-delay effect. In this study, Lyapunov's direct approach is employed to compute demanded voltage for MR dampers. Using Lyapunov's direct algorithm guarantees the system stability to design a controller based on feedback. Because of the strong nonlinearity of MR dampers, the equation of motion of coupled structures becomes an involved equation, and it is impossible to solve it with the common time step methods. In present paper modified Newmark-Beta integration based on the instantaneous optimal control algorithm, used to solve the involved equation. In this method, the response of a coupled system estimated base on optimal control force. Two MDOF structures with different degrees of freedom are finally considered as a numeric example. The numerical results show, the Newmark compensation is an efficient method to decrease the negative effect of time delay in coupled systems; furthermore, instantaneous optimal control algorithm can estimate the response of structures suitable.

A semi-active vehicle suspension based on pneumatic springs and magnetorheological dampers

Semi-active and active suspensions can improve both ride comfort and handling compared to passive suspensions. The authors have proposed a suspension comprising a pneumatic system capable of changing the stiffness of the suspension and a semi-active magnetorheological damper capable of controlling the suspension damping. Eight configurations of this magnetorheological/pneumatic suspension result from combining two possible stiffnesses (compliant and stiff) and four possible means of producing damping (constant low, constant high, on-off skyhook control and on-off balance control). The minimization of a cost function, which considers both ride comfort and handling, leads to decision maps which indicate the most appropriate configuration depending on vehicle velocity and two pieces of information about the road: the international roughness index and the curve radius. All this information can be gathered from a GPS system and toggling between set-ups is fast, efficient, and easily done by simply opening or closing pipes in the pneumatic system and modifying the current supply in the magnetorheological dampers. The proposed magnetorheological/pneumatic suspension achieves the same roll angle levels as in a comparable passive vehicle while improving ride comfort by reducing acceleration by up to 30%.

Smart semi-active MR damper to control the structural response

One advanced means of protecting structures against earthquake ground motions is the use of semi-active devices to customise and limit structural response. Thus, the design, modelling and analysis of different semi-active control devices have received increasing research attention. This study presents a method to determine optimal control forces for magneto-rheological (MR) dampers, using three algorithms: a discrete wavelet transform (DWT), a linear quadratic regulator (LQR), and a clipped-optimal control algorithm. DWT is used to obtain the local energy distribution of the motivation over the frequency bands to modify conventional LQR. The clipped-optimal control algorithm is used to get the MR damper control force to approach the desired optimal force obtained from modified LQR. A Bouc-Wen phenomenological model is utilized to capture the observed nonlinear behaviour of MR dampers. Time history analysis for a single degree of freedom (SDOF) with periods of T= 0.2-5.0 sec is utilized to compare the impact of using classic and modified LQR in controlling the MR damper force under 20 design level earthquakes of the SAC (SEAOC-ATC-CUREE) project. Performance is assessed by comparing the maximum displacement (Sd), total base shear (Fb) and the controller energy. This study shows the proposed modified LQR is more effective at reducing displacement response than conventional LQR. The modified LQR method reduces the median value of uncontrolled Sd by approximately 40% to 88%, over all periods to 5.0 seconds. Moreover, the modified LQR uses about 45% less energy than conventional LQR. Overall, these results indicate the robustness of the proposed method to mitigate structural response and damage using MR devices.

Semiactive Magnetorheological Damper for High Aspect Ratio Boring Process

This paper aims to develop a new semiactive damper to attenuate chatter vibration of a high aspect ratio boring bar. Design of the damper utilizes magnetorheological (MR) fluid and an electromagnet to control a damping force by a current input during machining process so as to effectively attenuate the chatter vibration. Various aspects of research on MR fluid and dynamic characteristics of boring operation and the MR damper have been investigated; First of all, effectiveness of MR fluid on attenuating vibration has been investigated by various designs of the damper and magnetic field. Then, the behavior of the MR fluid is simulated and its result is utilized to estimate dynamic motion of the MR actuator. Furthermore, simulation of the boring tool, force, and stability model shows significant improvement in machine chatter particularly for a high aspect ratio boring bar. The results provide a fundamental understanding to estimate dynamic vibration of the boring bar and offers optimal conditions for effectively attenuating chatter vibration. Finally, various experiments have been demonstrated to identify parameters of the MR damper and the results of boring machining show damper attenuation capability for wide frequency band by various cutting conditions corresponding to chatter frequencies.

Theoretical study of a twin-tube magnetorheological damper concept

In this study, the author presents a theoretical model of a semi-active magnetorheological (MR) twin-tube damper concept. The model relies on geometric variables and material properties and can be used in engineering and research studies on damper structures. Other non-linear characteristics, namely, the fluid chamber compressibility, fluid inertia, cylinder elasticity, friction, one-way check valves are included into the model as well. The author studies the performance of the damper model as design variables are varied, and the results are analysed and discussed.

Tyre force control strategy for semi-active magnetorheological damper suspension system for light-heavy duty truck

A semi-active controller scheme for magnetorheological (MR) damper of a light-heavy vehicle suspension known as Tyre Force Control (TFC) is proposed. The effectiveness of the proposed TFC algorithm is compared with Groundhook (GRD) control. A simulation model was developed and simulated using MATLAB Simulink software. The performance of the semi-active MR damper using TFC is analytically studied. Ride test was conducted at three different speeds and two different bumps, and the simulation results of TFC and GRD are compared and analysed. The results showed that the proposed controller is able to reduce tyre force significantly compared to GRD control strategy.

Damping Force Tracking Control of MR Damper System Using a New Direct Adaptive Fuzzy Controller

This paper presents a new direct adaptive fuzzy controller and its effectiveness is verified by investigating the damping force tracking control of magnetorheological (MR) fluid based damper (MR damper in short) system. In the formulation of the proposed controller, a model of interval type 2 fuzzy controller is combined with the direct adaptive control to achieve high performance in vibration control. In addition,H∞(Hinfinity) tracking technique is used in building a model of the direct adaptive fuzzy controller in which an enhanced iterative algorithm is combined with the fuzzy model. After establishing a closed-loop control structure to achieve high control performance, a cylindrical MR damper is adopted and damping force tracking results are obtained and discussed. In addition, in order to demonstrate the effectiveness of the proposed control strategy, two existing controllers are modified and tested for comparative work. It has been demonstrated from simulation and experiment that the proposed control scheme provides much better control performance in terms of damping force tracking error. This leads to excellent vibration control performance of the semiactive MR damper system associated with the proposed controller.

Nonlinear adaptive control of semi-active MR damper suspension with uncertainties in model parameters

This paper is concerned with vibration mitigation of a quarter car model using a semi-active magnetorheological (MR) damper. A nonlinear adaptive controller is proposed for vibration attenuation of the quarter car suspension system equipped with MR damper. Proposed adaptive controller can also compensate the uncertainties related to both quarter car model and the MR damper. Moreover, a nonlinear observer is designed to estimate an internal state variable of the MR damper. The mathematical model of the damper which is strongly nonlinear is used to predict the damping force based on velocity input, internal state and voltage input. An experimental test set-up is constructed to validate the MR damper parameters which are adapted by designed controller. Efficiency of adaptive controller is compared with separately designed linear $$\hbox {H}\infty $$ controller and passive cases under bump, sine and C-grade road inputs. The proposed adaptive controller is able to achieve good performance in road holding and driving comfort despite uncertainties in model parameters.

Semi-active magnetorheological dampers for reducing response of high-speed railway bridges

To reduce the resonant response of high-speed railway bridges, semi-active magnetorheological dampers are proposed in this study. The elements are connected to the structure in a double beam configuration. An H∞ control algorithm to drive magnetorheological damping forces of MR dampers is derived. Feasible solutions for an uncertain time-delay model are obtained by using standard linear matrix inequality techniques. Weight functions as a loop shaping procedure are also introduced in the feedback controllers to improve the tracking ability of magnetorheological damping forces. To this end, the effectiveness of magnetorheological dampers controlled by the proposed scheme, along with the effects of the uncertain and the time-delay parameters on the models, are evaluated and compared with the performance of fluid viscous dampers in similar applications reported in previous research through numerical simulations.

ANALYSIS OF THE STEADY STATE UNBALANCE RESPONSE OF RIGID ROTORS ON MAGNETORHEOLOGICAL DAMPERS: STABILITY, FORCE TRANSMISSION AND ENERGY DISSIPATION

The rotors working in real technological devices are always slightly imbalanced. This excites their lateral vibrations and generates forces that are transmitted to the rotor casing. These effects can be significantly reduced if damping devices are added to the support elements. The possibility of controlling the damping, in order to achieve their optimum performance, is offered by magnetorheological squeeze film dampers. In this paper, a computational modeling method is used to investigate the dynamical behavior of a rigid flexibly supported rotor loaded by its unbalance and equipped with two short magnetorheological dampers. The equations of motion of the rotor are nonlinear due to the damping forces. Computational procedures were developed to verify the applicability of such dampers by simulating their behavior and analyzing their effect on the amplitude of the rotor vibration, on the magnitude of the forces transmitted to the rotor casing and on the amount of the power dissipated in the magnetorheological films. The proposed approach to study the optimum performance of semiactive magnetorheological dampers applied in rotor systems, in terms of vibration amplitudes and transmitted forces, together with the developed efficient computational methods to calculate the system steady state response and to evaluate its stability represent the new contributions of this paper.

MR 댐퍼를 이용한 비대칭 사장교의 지진 진동제어 성능평가

비대칭 사장교에 지진으로 인한 진동을 MR(Magneto-rheological) 댐퍼를 이용하여 효과적으로 제어하는 연구를 수행하였다. MR 댐퍼의 실용적인 사용성을 높이기 위하여 비대칭 사장교 구조물을 설계/제작하고, 이 교량구조물을 적정하게 제어할 수 있도록 MR 댐퍼를 제작하였다. El-centro 지진파로 비대칭 사장교를 수평방향으로 가진하여 수직방향과 수평방향의 진동을 제어하는 실험을 하였다. 각 방향의 진동제어 실험에 5가지의 제어 조건으로 MR 댐퍼의 제어성능을 평가 하였다. 실험결과 MR 댐퍼는 지진진동으로 인한 비대징사장교를 진동제어 하기 위하여 Lyapunov Control 알고리즘과 Clipped-optimal control 알고리즘을 이용하여 제어를 할 경우, 보다 효과적으로 진동을 제어하는 것을 알 수 있었다. 그리고 구조물의 비대칭성과 수평 가진으로 인하여 수직 및 수평 방향의 진동제어가 서로 다른 제어효과를 보였다. 이와 같은 제어효과는 비대칭 사장교와 같은 유연하며 비대칭인 구조물에 준능동의 MR 댐퍼가 효과적으로 지진진동을 제어하는 것으로 평가되었다. A study has been carried out that effectively controls the vibration of asymmetric cable-stayed bridges caused by earthquakes with MR dampers. In order to enhance the practical serviceability of MR dampers, an asymmetric cable-stayed bridge structure has been designed and produced, and a MR damper has been produced so as to have this bridge structure controlled appropriately. An experiment that controls vertical and horizontal vibrations has been carried out by exciting the asymmetric cable-stayed bridge in the horizontal direction with the El-centro seismic wave. The control performance of the MR damper has been evaluated under the five control conditions in the experiments of vibration control in each direction. As a result of the experiment, MR dampers were proved to control vibrations more effectively when either Lyapunov control algorithm or Clipped-optimal control algorithm was used to control vibrations of the asymmetric cable-stayed bridge caused by earthquakes. In addition, different controlling effects were found in vibration controls in vertical and horizontal directions due to the asymmetry of the structure and the horizontal excitation. With such controlling effects, semi-active MR dampers are evaluated to effectively control vibrations caused by earthquakes in flexible and asymmetric structures such as asymmetric cable-stayed bridges.

An Adaptive Neuro Fuzzy Hybrid Control Strategy for a Semiactive Suspension with Magneto Rheological Damper

The main function of a vehicle suspension system is to isolate the vehicle body from external excitation in order to improve passenger comfort and road holding and to stabilise its movement. This paper considers the implementation of an adaptive neuro fuzzy inference system (ANFIS) with a fuzzy hybrid control technique to control a quarter vehicle suspension system with a semiactive magneto rheological (MR) damper. A quarter car suspension model is set up with an MR damper and a semiactive controller consisting of a fuzzy hybrid skyhook-groundhook controller and an ANFIS model is also designed. The fuzzy hybrid controller is used to generate the desired control force, and the ANFIS is designed to model the inverse dynamics of MR damper in order to obtain a desired current. Finally, numerical simulations of the semiactive suspensions with the ANFIS-hybrid controller, the traditional hybrid controller, and passive suspension are compared. The results of simulations show that the proposed ANFIS-hybrid controller provides better isolation performance than the other controllers.

Recent Advances on Vibration Control of Structures Under Dynamic Loading

In this paper, a review of recent journal articles on passive, active, semi-active, and hybrid vibration control of structures subjected to dynamic loading is presented. Passive systems reviewed include tuned mass damper (TMD), tuned liquid column damper (TLCD), tuned liquid column ball damper (TLCBD), circular TLCD (CTLCD), and pendulum TLCD (PTLCD). Active control systems include active tuned mass dampers (ATMD) and piezoelectric actuators. Semi-active systems include magnetorheological (MR) damper, negative stiffness devices (NSD), magneto-rheological damper TMD (MR-TMD), variable stiffness semi-active TMD (VS-STMD), variable damper STMD (VD-STMD), and recentering variable friction device (RVFD). Hybrid systems include active base isolation system and semi-active MR dampers with nonlinear base isolators. The current frontier of research is semi-active control of structures as well hybridization of various control systems. The problem is complex requiring integration of several different hardware and software technologies with structural design such as smart materials, adaptive dampers, actuators, sensors, and control and signal processing algorithms. This complexity also makes it an exciting area of research and development.

Semi-active magnetorheological refueling probe systems for aerial refueling events

This study analyzes the feasibility of applying a semi-active magnetorheological (MR) damper to a naval hose–drogue based aerial refueling system to minimize undesirable hose–drogue vibrations. The semi-active smart aerial refueling probe system consists of a probe, a coil spring, and a MR damper. The dynamics of the smart refueling probe system were derived and incorporated into an analysis of the coupled hose–drogue dynamics, so as to evaluate the load reduction of the refueling hose at the drogue position effected by the MR damper. The simulated responses of the smart refueling probe system using a MR damper were conducted at different maximum closure velocities of 1.56 and 5 ft s−1 and different tanker flight speeds of 185 and 220 knots. The simulations demonstrate that the smart refueling probe system using a MR damper enables large reductions in probe-and-drogue motions, as well as preventing the onset of large and undesirable hose–drogue motions resulting from tension loads during engagement of the probe.