Vehicle Evaluation of the Performance of Magneto Rheological Dampers for Heavy Truck Suspensions

2001 ◽  
Vol 123 (3) ◽  
pp. 365-375 ◽  
Author(s):  
David Simon ◽  
Mehdi Ahmadian
Keyword(s):  
Control Policy ◽  
Field Evaluation ◽  
Vehicle Body ◽  
Mr Dampers ◽  
Heavy Trucks ◽  
Acceleration Data ◽  
Passive Dampers ◽  
Heavy Truck ◽  
Driving Conditions ◽  
Magneto Rheological

This study is intended to complement many existing analytical studies in the area of semiactive suspensions by providing a field evaluation of semiactive magneto rheological (MR) primary suspensions for heavy trucks. A set of four controllable MR dampers are fabricated and used experimentally to test the effectiveness of a semiactive skyhook suspension on a heavy truck. In order to evaluate the performance of the semiactive suspensions, the performance of the truck equipped with the MR dampers is primarily compared with the performance of the truck equipped with the stock passive dampers. The performance of the semiactive system and the original passive system are compared for two different driving conditions. First, the truck is driven over a speed bump at approximately 8–11 kmh (5–7 mph) in order to establish a comparison between the performance of the MR and stock dampers to transient inputs at the wheels. Second, the truck is driven along a stretch of relatively straight and level highway at a constant speed of 100 kmh (62 mph) in order to compare the performance of the two types of dampers in steady state driving conditions. Acceleration data for both driving conditions are analyzed in both time and frequency domains. The data for the speed bumps indicate that the magneto rheological dampers used (with the skyhook control policy) in this study have a small effect on the vehicle body and wheel dynamics, as compared to the passive stock dampers. The highway driving data shows that magneto rheological dampers and the skyhook control policy are effective in reducing the root mean square (RMS) of the measured acceleration at most measurement points, as compared to the stock dampers.

Improving Roll Stability of Vehicles With High Center of Gravity by Using Magneto-Rheological Dampers

2002 ◽  
Author(s):  
Mehdi Ahmadian ◽  
David E. Simon
Keyword(s):  
Control Method ◽  
Vehicle Body ◽  
Semiactive Control ◽  
Sport Utility Vehicle ◽  
Mr Dampers ◽  
Different Types ◽  
Magneto Rheological ◽  
Utility Vehicle ◽  
High Center ◽  
Stock Suspension

The performance of a new semiactive control method for improving roll stability of sport utility vehicles (SUVs) is discussed, using a series of road tests. The new method augments the conventional skyhook control for semiactive suspensions with steering input, in order to account for the suspension requirements during a lateral maneuver. After discussing the formulation for the steering input augmented (SIA) skyhook control, the paper includes the implementation of a semiactive system with magneto-rheological (MR) dampers on a sport utility vehicle. The vehicle is used for a series of road tests that includes lane change maneuvers, with different types of suspensions. The suspensions that are tested include the stock suspension, the uncontrolled MR dampers, skyhook control, and SIA skyhook. The results of the study show that SIA skyhook can improve the suspension travel and lateral forces at the vehicle body during maneuvers, as compared to other suspensions evaluated on the vehicle.

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.

Vibration Control of a New Bed Stage System for Ambulance Using MR Dampers

2014 ◽  
Author(s):  
Hee-Dong Chae ◽  
Seung-bok Choi ◽  
Jong-Seok Oh
Keyword(s):  
Mathematical Model ◽  
Vibration Control ◽  
Vibration Isolation ◽  
Design Parameters ◽  
Ride Quality ◽  
Vibration Level ◽  
Mr Dampers ◽  
Secondary Damage ◽  
Stage System ◽  
Magneto Rheological

This paper proposes a new bed stage for patients in ambulance vehicle in order to improve ride quality in term of vibration control. The vibration of patient compartment in ambulance can cause a secondary damage to a patient and a difficulty for a doctor to perform emergency care. The bed stage is to solve vertical, rolling, and pitching vibration in patient compartment of ambulance. Four MR (magneto-rheological) dampers are equipped for vibration isolation of the stage. Firstly, a mathematical model of stage is derived followed by the measurement of vibration level of patient compartment of real ambulance vehicle. Then, the design parameters of bed stage is undertaken via computer simulation. Skyhook, PID and LQR controllers are used for vibration control and their control performances are compared.

Steady-State Energy Transfer of a Semi-Active Suspension Under Hybrid Control

2004 ◽  
Author(s):  
Christopher M. Boggs ◽  
Fernando D. Goncalves ◽  
Mehdi Ahmadian
Keyword(s):  
Steady State ◽  
Energy Dissipation ◽  
Yield Stress ◽  
Hybrid Control ◽  
Mr Damper ◽  
Control Policy ◽  
Mr Fluid ◽  
Mr Dampers ◽  
Field Dependent ◽  
System Energy

Magnetorheological (MR) fluids are often characterized by their field-dependent yield stress. Upon the activation of a magnetic field, the fluid has the ability to change from a fluid state to a semi-solid state in milliseconds. The field-dependent yield stress and the fluid’s fast response time make MR fluid an attractive technology for many applications. One such application that has gained considerable attention is in MR fluid dampers. The real-time control possibilities make MR dampers attractive alternatives to conventional viscous dampers. In comparing passive dampers with MR dampers, an equivalent viscous damping coefficient is often found from the energy dissipated by the MR damper with a fixed current applied to the damper. In contrast, this study investigates energy dissipation of the MR damper under a semi-active hybrid control policy. Hybrid control is a linear combination of skyhook and groundhook control. This study investigates the system energy under steady-state conditions at three frequencies, and how the system energy varies with varying contributions from skyhook and groundhook. A quarter-car rig was used to evaluate the dynamics of the hybrid suspension using an MR damper. Previous studies have shown that hybrid control can offer advantages to both the sprung and unsprung masses; however the relationship between energy dissipation and performance is not clear. In this study, we compare control policy performance to several energy-based measures. Results indicate that there is a strong correlation between sprung mass RMS acceleration and unsprung mass RMS acceleration to several of the energy-based measures.

Investigation of Heavy Truck Restraint System Effectiveness Through Finite Element Computer Simulations in Frontal Crashes

2016 ◽  
Author(s):  
Nathan Schulz ◽  
Chiara Silvestri Dobrovolny ◽  
Abhinav Mohanakrishnan
Keyword(s):  
Finite Element ◽  
Injury Severity ◽  
Seat Belt ◽  
Restraint System ◽  
Rigid Barrier ◽  
Heavy Trucks ◽  
Ring Location ◽  
Heavy Truck ◽  
Frontal Crashes ◽  
Occupant Kinematics

Computer finite element simulations play an important role in reducing the cost and time taken for prediction of a crash scenario. While interior crash protection has received adequate attention for automobiles, very little is known for commercial vehicle such as heavy trucks. The understanding of injury types for heavy trucks occupants in relation to different crash scenarios would help mitigation of the injury severity. Finite element computer models of the heavy truck cabin structure, interior cabin components, anthropomorphic test device (ATD) (also called dummy) and passive restraint systems were developed and assembled to simulate head-on crash of a heavy truck into a rigid barrier. The researchers developed a computer simulation parametric evaluation with respect to specific seat belt restraint system parameters for a speed impact of 56.3 km/h (35 mph). Restraint parameter variations within this research study are seat belt load limiting characteristics, inclusion of seat belt pretensioner, and variation of seat belt D-ring location. Additionally an airbag was included to investigate another restraint system. For each simulated impact characteristic and restraint system variation, the occupant kinematics were observed and occupant risks were assessed. Within the approximations and assumptions included in this study, the results presented in this paper should be considered as preliminary guidance on the effectiveness of the use of seat belt as occupant injury mitigation system.

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.

Experimental Dynamic Analysis of Magneto-Rheological Tuned Vibration Absorbers

2003 ◽  
Author(s):  
Jeong-Hoi Koo ◽  
Mehdi Ahmadian ◽  
Mehdi Setareh ◽  
Thomas M. Murray
Keyword(s):  
Active Control ◽  
Primary Structure ◽  
Control Policy ◽  
Vibration Absorbers ◽  
Control Policies ◽  
Output Displacement ◽  
Tuned Vibration Absorbers ◽  
Control Schemes ◽  
Displacement Based ◽  
Magneto Rheological

The primary purpose of this study is to experimentally evaluate the dynamics of a Magneto-Rheological Tuned Vibration Absorber (MR TVA) with several semi-active control schemes. A test rig was built to represent a two-degree of freedom primary structure model coupled with an MR TVA, and four semi-active control policies were considered. The four control policies include: velocity-based, on-off groundhook control (on-off VBG); velocity-based, continuous groundhook control (continuous VBG); displacement-based, on-off groundhook control (on-off DBG); and displacement-based, continuous groundhook control (continuous DBG). Using the test apparatus, a series of tests were conducted to investigate the dynamics of the MR TVA with each control policy. The performances of each of the cases were then analyzed along with the equivalent passive TVA. The performance index was the transmissibility between the input and the output displacement of the structure. The experimental results indicated that the MR TVA with all of the semi-active control policies, outperformed the passive TVA in reducing structural vibrations. Furthermore, the displacement-based groundhook control policies perform better in reducing the resonant vibrations of the primary structure than the velocity-based groundhook control schemes.

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