Experimental Approach for Finding the Response Time of MR Dampers for Vehicle Applications

2003 ◽  
Author(s):  
Fernando D. Goncalves ◽  
Jeong-Hoi Koo ◽  
Mehdi Ahmadian
Keyword(s):  
Response Time ◽  
Time Constant ◽  
Constant Velocity ◽  
Mr Damper ◽  
Initial State ◽  
Final State ◽  
Mr Dampers ◽  
Automotive Suspension ◽  
Magneto Rheological ◽  
Time Required

This paper offers a method and an experimental example of determining the response time of Magneto-Rheological (MR) dampers. The response time of MR dampers for automotive suspension applications is valuable information because it is one of the key factors that determine the practical effectiveness of the use of MR dampers in vehicles. However, a detailed description of the response time of MR dampers is seldom given in the literature. Furthermore, the methods of computing the response time are not discussed in detail. Therefore, this study intends to develop a method for experimental determination of the response time of MR dampers for automotive suspensions. A triangle wave that maintains a constant velocity across the damper is proposed as the input to use in experiments. This triangle wave ensures a constant velocity across the damper in order to accurately evaluate the response time of the MR damper. The response time was defined as the time required to make the transition from the initial state to 63.2% of the final state, or one time constant. The time constant is a measure of how long it takes a system to respond to a given input. In other words, the response time is the time necessary for the damper to achieve the desired force upon activation. To demonstrate the method, the response time was found for an MR damper particularly designed and fabricated for vehicle applications. Two cases were considered: activation response time of the damper and deactivation response time of the damper. Both cases were studied during the rebound stroke of the damper. It was found that the response time of the MR damper under activation and deactivation was 15.4 ms and 13.9 ms respectively. The results are comparable to those found in the literature.

A Reliability Assessment Model for MR Damper Components within a Smart Structural Control Scheme

2008 ◽  
Vol 56 ◽  
pp. 218-224
Author(s):  
Maguid H.M. Hassan
Keyword(s):  
Structural Control ◽  
Inverse Dynamics ◽  
Mr Damper ◽  
Assessment Model ◽  
Resistance Force ◽  
Mr Dampers ◽  
Control Scheme ◽  
Smart Control ◽  
Control Devices ◽  
Magneto Rheological

Smart control devices have gained a wide interest in the seismic research community in recent years. Such interest is triggered by the fact that these devices are capable of adjusting their characteristics and/or properties in order to counter act adverse effects. Magneto-Rheological (MR) dampers have emerged as one of a range of promising smart control devices, being considered for seismic applications. However, the reliability of such devices, as a component within a smart structural control scheme, still pause a viable question. In this paper, the reliability of MR dampers, employed as devices within a smart structural control system, is investigated. An integrated smart control setup is proposed for that purpose. The system comprises a smart controller, which employs a single MR damper to improve the seismic response of a single-degree-of-freedom system. The smart controller, in addition to, a model of the MR damper, is utilized in estimating the damper resistance force available to the system. On the other hand, an inverse dynamics model is utilized in evaluating the required damper resistance force necessary to maintain a predefined displacement pattern. The required and supplied forces are, then, utilized in evaluating the reliability of the MR damper. This is the first in a series of studies that aim to explore the effect of other smart control techniques such as, neural networks and neuro fuzzy controllers, on the reliability of MR dampers.

Application of Magneto Rheological Dampers for Controlling Shock Loading

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
James C. Poynor ◽  
Jason M. Gooch
Keyword(s):  
Dynamic System ◽  
Shock Loading ◽  
Closed Loop ◽  
Shock Absorber ◽  
Mr Damper ◽  
Test Results ◽  
Closed Loop System ◽  
Mr Dampers ◽  
Shock Dynamics ◽  
Magneto Rheological

Abstract This study will examine the effectiveness of magneto-rheological (MR) dampers for controlling shock dynamics. Using a system that includes a 50-caliber rifle and a magneto-rheological damper, it is experimentally shown that MR dampers can be quite effective in controlling the compromise that commonly exists between shock forces and strokes across the shock absorber mechanism. A series of tests are conducted to demonstrate that different damping forces by the MR damper can result in different shock-force/stroke profiles. The test results further show that MR dampers can be used in a closed-loop system to adjust the shock loading characteristics in a manner that fits the dynamic system constraints and requirements.

A Non Parametric Model for Magneto Rheological Dampers

1999 ◽  
Author(s):  
Mehdi Ahmadian ◽  
Xubin Song
Keyword(s):  
Test Data ◽  
Mr Damper ◽  
Parametric Model ◽  
Parametric Models ◽  
Magnetic Saturation ◽  
Mr Dampers ◽  
Electro Magnetic ◽  
Magneto Rheological ◽  
Force Characteristics ◽  
Non Parametric

Abstract A non-parametric model for magneto-rheological (MR) dampers is presented. After discussing the merits of parametric and non-parametric models for MR dampers, the test data for a MR damper is used to develop a non-parametric model. The results of the model are compared with the test data to illustrate the accuracy of the model. The comparison shows that the non-parametric model is able to accurately predict the damper force characteristics, including the damper non-linearity and electro-magnetic saturation. It is further shown that the parametric model can be numerically solved more efficiently than the parametric models.

Passenger Comfort Analysis in an Automotive Considering a Magneto-Rheological Damper based Suspension

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
R.B. Soujanya ◽  
D.D. Jebaseelan ◽  
S. Kannan
Keyword(s):  
Ride Comfort ◽  
Mr Damper ◽  
Nonlinear Behaviour ◽  
Passive Damping ◽  
Damping Force ◽  
The Road ◽  
Mr Dampers ◽  
Moving Vehicles ◽  
Magneto Rheological ◽  
Multi Body

Passenger’s comfort in moving vehicles depends on the quality of the ride. The major cause of discomfort is the vibration transmitted to passengers due to the road irregularities. For a comfortable ride on a vehicle, vibration must stay within prescribed standards. In the present work, an attempt was made to show that, the vibrations can be limited with the use of Magneto-rheological (MR) dampers for varying road profiles than the passive damping methods. MR dampers are semi-active control devices that use MR fluids to produce controllable damping force as they are known to exhibit nonlinear behaviour. Multi body dynamic studies were done to study the response of the system using a quarter car model. In this paper, passive damping (viscous damping) was considered at natural frequency of 1.012Hz, the response of damping was observed after 10s and the acceleration was found to be 6m/s2. When MR damper is employed as the magnetic force increases, the response of the damping was better than the passive damping, at 1.2A it comes down to 0.55m/s2, and the vibration gets dampened after 1.75s. Hence, from this study it is concluded that the MR damper can be employed in automobile for better ride comfort.

scholarly journals Vibration modeling of a vehicle equipped with MR damper and aerodynamic elements

2019 ◽  
Vol 20 (1-2) ◽  
pp. 57-61
Author(s):  
Wiesław Grzesikiewicz ◽  
Michał Makowski
Keyword(s):  
High Speed ◽  
Mr Damper ◽  
Road Surface ◽  
Vehicle Model ◽  
Numerical Investigations ◽  
The Road ◽  
Mr Dampers ◽  
On The Road ◽  
Magneto Rheological ◽  
Vibration Modeling

We considered of a vehicle model equipped with controlled magneto-rheological (MR) dampers and controlled aerodynamic elements. The vibrations of the vehicle moving at high speed during acceleration and braking are analysed. The purpose of this analysis is to determine the effect of forces generated on aerodynamic elements on vehicle vibrations and changes in wheel pressure on the road surface during acceleration and braking. The presented work presents the results of numerical investigations obtained on the basis of the developed vehicle model.

Design and Development of Magneto Rheological Dampers for Bicycle Suspensions

1999 ◽  
Author(s):  
Mehdi Ahmadian
Keyword(s):  
Dynamic Performance ◽  
Mr Damper ◽  
Test Results ◽  
Design And Development ◽  
Damping Force ◽  
Mr Fluid ◽  
Performance Improvements ◽  
Mr Dampers ◽  
Force Velocity ◽  
Magneto Rheological

Abstract The design and fabrication of a magneto rheological (MR) damper for bicycle suspension applications is addressed. Two 1998 Judy® Dampers are retrofitted with MR valves, to achieve the damping force adjustability that the MR fluid offers. One design attempts to use as many of the Judy® Damper components as possible. The second design significantly modifies the Judy® Damper, to better accommodate the MR valve and ease of fabrication and assembly, although fitting into the same envelope as the Judy® damper for a direct retrofit. The two MR dampers are fabricated and assembled for force-velocity characterization testing. The test results show that properly-designed MR dampers can provide significant dynamic performance improvements, as compared to conventional passive bicycle dampers.

Improving Vehicle Performance and Operator Ergonomics: Commercial Application of Smart Materials and Systems

2011 ◽  
Author(s):  
Douglas Ivers ◽  
Douglas LeRoy
Keyword(s):  
Smart Materials ◽  
Mr Damper ◽  
Electrical Current ◽  
Step Response ◽  
Commercial Application ◽  
Material Technology ◽  
Mr Fluid ◽  
Mr Dampers ◽  
Magneto Rheological ◽  
Scale Step

This paper will discuss how controllable material technology, such as the use of active magneto-rheological (MR) dampers, improves vehicle primary and secondary suspensions. Although relatively new to the marketplace, semi-active suspensions in commercial automobiles and off-highway vehicles have been proven through the use of active MR dampers since 1998. In fact, MR suspension dampers are found today on the commercial vehicles of an increasing number of automotive OEMs and leading off-highway OEMs. MR fluid dampers are simple in design and have the advantage of no moving parts. The resistive force from an MR damper is generated as iron particles, suspended in the magneto-rheological fluid (MR fluid); pass through a magnetic field controlled by the electrical current passing through an electric coil contained within a moving piston surrounded by fluid. By adjusting the current to the damper coil in response to feedback from vehicle sensors and a controller, the damping response of the suspension can be optimized and controlled in real time to provide optimal operator comfort. The MR Damper System has a full-scale step response of less than 10 milliseconds. Sophisticated control algorithms adapt to large changes in payload, enabling the vehicle to meet ride metrics without pneumatic load leveling. Other benefits of the MR damping system include higher speed in NATO double-lane change tests, reduced risk of roll-over, improved accuracy of mounted weapons, and improved vehicle durability and readiness.

scholarly journals Control of an Automotive Semi-Active Suspension

2012 ◽  
Vol 2012 ◽  
pp. 1-21 ◽  
Author(s):  
Jorge de Jesús Lozoya-Santos ◽  
Ruben Morales-Menendez ◽  
Ricardo A. Ramírez Mendoza
Keyword(s):  
Frequency Estimation ◽  
Mr Damper ◽  
Response Analysis ◽  
Linear Parameter ◽  
Linear Parameter Varying ◽  
Mr Dampers ◽  
Model Free ◽  
Time Response Analysis ◽  
Magneto Rheological ◽  
Model Free Controller

Two controllers for an automotive suspensions with Magneto-Rheological (MR) dampers are proposed. One is a model-based using the Linear Parameter Varying (LPV) approach, and the other is a model-free controller with a Frequency Estimation Based (FEB) principle. The LPV controller includes an experimental nonlinear model of an MR damper using only one scheduling parameter. A comparison with a several semiactive controllers for comfort and road holding is discussed. The FEB controller is the best option based on frequency and time response analysis for comfort (10–20%), suspension deflection (30–50%), and road holding (1–5%).

Semi-Active Control of a Vehicle Suspension Based on Magneto-Rheological Damper

2011 ◽  
Vol 311-313 ◽  
pp. 2286-2290
Author(s):  
Jie Lai Chen ◽  
Xue Zheng Jiang ◽  
Ning Xu
Keyword(s):  
Ride Comfort ◽  
Mr Damper ◽  
Vehicle Suspension ◽  
Damping Force ◽  
Mr Dampers ◽  
Quarter Car ◽  
Set Up ◽  
Magneto Rheological ◽  
Two Degree Of Freedom ◽  
The Magnetic Field

The focus of this study is to experimentally investigate a semi-active magneto-rheological (MR) damper for a passenger vehicle, by using a quarter car models. After verifying that the damping force of the MR damper can be continuously tuned by the intensity of the magnetic field, a full-scale two-degree of freedom quarter car experimental set up is constructed to study the vehicle suspension. On-off skyhook controller is employed to achieve the desired damping force. The experimental results show that the semi-active vehicle suspension vibration control system based on MR dampers is feasible and can effectively improve ride comfort of vehicle.

Experimental Evaluation of an Adaptive Actuator Control Scheme for Real-Time Tests of Large-Scale Magneto-Rheological Damper Under Variable Current Inputs

2009 ◽  
Author(s):  
Cheng Chen ◽  
James M. Ricles
Keyword(s):  
Real Time ◽  
Hybrid Simulation ◽  
Mr Damper ◽  
Structural Systems ◽  
Adaptive Compensation ◽  
Hydraulic Actuator ◽  
Control Laws ◽  
Mr Dampers ◽  
Magneto Rheological ◽  
Actuator Control

A Magneto-Rheological (MR) fluid damper is a semi-active device for vibration control of engineering structures subjected to dynamic loading. The characteristics of MR dampers vary under different current inputs to achieve optimized vibration control of structural systems. Experimental evaluation of MR dampers under different control laws is necessary before the device can be accepted by the practical design community. Real-time hybrid simulation provides an economical and efficient dynamic testing technique by accounting for the damper rate-dependency and the damper-structure interaction. A successful real-time hybrid simulation requires accurate actuator control to achieve reliable experiment results. A servo-hydraulic actuator usually introduces a time delay due to servo-hydraulic dynamics. The variable current inputs induced by semi-active control laws would pose additional challenges for actuator control by introducing variable delay in a real-time hybrid simulation. In this paper an adaptive compensation technique is experimentally evaluated for real-time hybrid simulation involving an MR damper under variable current inputs. Predefined band-limited white noise is used as the displacement command for the servo-hydraulic actuator and current command for the MR damper. The adaptive compensation scheme is demonstrated to achieve accurate actuator control and therefore shows great potential for real-time hybrid simulation of structural systems with semi-active energy dissipation devices.

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