Electromagnetic Shock Absorbers for Automotive Suspensions: Electromechanical Design

2006 ◽  
Author(s):  
Nicola Amati ◽  
Aldo Canova ◽  
Fabio Cavalli ◽  
Stefano Carabelli ◽  
Andrea Festini ◽  
...  
Keyword(s):  
Shock Absorber ◽  
Dynamic Performance ◽  
Integrated Design ◽  
Design Procedure ◽  
Resistive Load ◽  
Added Resistance ◽  
Damping Force ◽  
Quarter Car Model ◽  
Car Model ◽  
Shock Absorbers

This article illustrates the modeling and design of electromechanical shock absorbers for automotive applications. Relative to the commonly used hydraulic shock absorbers, electromechanical ones are based on the use of linear or rotative electric motors. If electric motor is of the DC-brushless type, the shock absorber can be devised by shunting its electric terminals with a resistive load. The damping force can be modified by acting on the added resistance. An integrated design procedure of the electrical and mechanical parameters is presented in the article. The dynamic performance that can be obtained by a vehicle with electromechanical dampers is verified on a quarter car model.

Vibration Investigation of a Quarter Car with Nonlinear Shock Absorber Model

2012 ◽  
Vol 576 ◽  
pp. 665-668
Author(s):  
Fadly Jashi Darsivan ◽  
Waleed F. Faris
Keyword(s):  
Shock Absorber ◽  
Model Simulation ◽  
Damping Force ◽  
Quarter Car Model ◽  
Car Model ◽  
Road Profile ◽  
Non Linear ◽  
Nonlinear Shock ◽  
Quarter Model ◽  
Quarter Car

The paper discusses the response and the accuracy of a quarter car model with a non-linear damping force. The non-linear shock absorber model was a result of an experiment that was conducted earlier and the mathematical model was verified. Based on this model simulation responses of the sprung and unsprung masses between a linear and the non-linear damper were compared. The wheel of the quarter car model was excited by a road profile and according to the results the non-linear quarter model showed responses which were not depicted and captured by the linear model.

Double Adjustable Shock Absorbers Utilizing Electrorheological and Magnetorheological Fluids

2000 ◽  
Author(s):  
Jason E. Lindler ◽  
Norman M. Wereley
Keyword(s):  
Shock Absorber ◽  
Force Measurements ◽  
Damping Force ◽  
University Of Maryland ◽  
Shock Absorbers ◽  
Piston Head ◽  
Performance Requirements ◽  
Velocity Response ◽  
The University ◽  
Yield Force

Abstract Double adjustable shock absorbers allow for independent adjustment of the yield force and post-yield damping in the force versus velocity response. To emulate the performance of a conventional double adjustable shock absorber, an electrorheological (ER) and magnetorheological (MR) automotive shock absorber were designed and fabricated at the University of Maryland. For the ER shock absorber, an applied electric field between two tubular electrodes, located in the piston head, increases the force required for a given piston rod velocity. For the MR shock absorber, an applied magnetic field between the core and flux return increases the force required for a given piston rod velocity. For each shock absorber, two different shaped gaps meet the controllable performance requirements of a double adjustable shock absorber. A uniform gap allows for control of the yield force of the shock absorber, while a non-uniform gap allows for control of the post-yield damping. Force measurements from sinusoidal displacement cycles, recorded on a mechanical damper dynamometer, validate the performance of uniform and non-uniform gaps for adjustment of the yield force and post-yield damping, respectively.

Magnitude of Axle Tramp Response to Partially Detreaded Tire Imbalance in Highway-Speed Driving

2012 ◽  
Author(s):  
Paul T. Semones ◽  
David A. Renfroe
Keyword(s):  
High Speed ◽  
Rear Axle ◽  
Shock Absorber ◽  
The United States ◽  
Damping Force ◽  
Shock Absorbers ◽  
Light Trucks ◽  
Single Vehicle ◽  
Frontal Collisions ◽  
Rear Tire

Tire tread separations on light trucks and SUVs have resulted in numerous catastrophic highway accidents over the past two decades in the United States. These accidents frequently involve single-vehicle rollovers or deviations of the impaired vehicle into oncoming traffic, where high speed frontal collisions may ensue. On light trucks and SUVs equipped with a Hotchkiss rear suspension, one explanation for the loss of driver control during an in-process rear tire tread separation is solid axle tramp response to the imbalanced separating tire. This explanation has met with some controversy. The present study will demonstrate that the imbalance forces generated at highway speeds from a partially detreaded tire are sufficient to induce continuous cyclical axle tramp, and can even be sufficient to completely elevate rear-axle tires out of contact with the paved roadway. This imbalance-induced tramping action may be exacerbated during braking and the vehicle’s terminal yaw, when rear traction is crucial to avoiding a catastrophic accident. In addition to test data, several field examples of such events are presented. A key metric of solid axle response to an imbalanced, partially detreaded tire is shock absorber motion. In the present study, shock absorber displacement on the test vehicles, as measured during highway speed tread separation axle tramp events, is found to oscillate through a stroke generally less than one inch (2.5 cm) in length at a frequency in excess of 10 Hz. Peak instantaneous velocities of the shock absorber have been observed as high as 40 in/s (16 cm/s) or more during straight driving under axle tramp conditions. Confirming several previously published findings, the present study shows that increasing shock damping force at the higher operational velocities of the shock absorber reduces the magnitude of axle tramp and assists in keeping the rear axle tires in contact with the ground. Additionally, increasing the distance between the shock absorbers by moving them closer to the wheels provides the same advantage.

Modeling and Control of Magnetorheological Dampers for Vibration Isolation

2003 ◽  
Author(s):  
A. Narimani ◽  
M. F. Golnaraghi
Keyword(s):  
Vibration Isolation ◽  
Mr Damper ◽  
Damping Force ◽  
Isolation System ◽  
Modeling And Control ◽  
Quarter Car Model ◽  
Car Model ◽  
Quarter Car ◽  
Set Up ◽  
And Control

Semi-active isolators offer significant improvement in performance over passive isolators. These systems benefit from the advantages of active systems with the reliability of the passive systems. In this work we study a vibration isolation system with a magnetorheological (MR) damper. The experimental investigation of the mechanical properties of a commercially available linear MR damper (RD-1005-3) was conducted next. The mathematical Bouc-Wen model was adopted to predict the performance of MR damper. In addition, a modified Bingham model has been developed to characterize the damper behavior more accurately and efficiently. The measured hysteresis characteristics of field-dependent damping forces are compared with the simulation results from the described mathematical models. The accuracy of a damping-force controller using the proposed method is also demonstrated experimentally. Finally, a scaled quarter car model is set up to study the performance of the control strategy. The experimental results show that with the semi-active control the vibration of the quarter car model is well controlled.

Damping force characteristics of electrorheological shock absorbers with different electrode designs

2010 ◽  
Vol 224 (2) ◽  
pp. 293-304 ◽  
Author(s):  
Y-M Han ◽  
M-S Seong ◽  
S-B Choi ◽  
N M Wereley
Keyword(s):  
Shock Absorber ◽  
Equations Of Motion ◽  
Design Parameters ◽  
Damping Force ◽  
Passenger Vehicles ◽  
Shock Absorbers ◽  
Car Suspension ◽  
Field Dependent ◽  
The Time Domain ◽  
Er Fluid

This article presents the effect of electrode design parameters on the damping force of an electrorheological (ER) shock absorber for passenger vehicles. As a first step, an ER fluid is synthesized by dispersing arabic gum particles into non-conducting oil, and its field-dependent Bingham characteristics are experimentally evaluated. The Bingham model of the ER fluid is then formulated and incorporated with the governing equations of motion of the ER shock absorber. Subsequently, several ER shock absorbers are designed and manufactured with various electrode designs, which have three different electrode gaps, lengths, and materials, respectively. The field-dependent damping force of the manufactured shock absorbers is demonstrated in the time domain and compared with simulation results. In addition, the vibration control performance of a quarter-car suspension system is presented and compared with different electrode gaps and lengths.

Research on the Influence of the Road-Friendliness by Semi-Active Suspension

2011 ◽  
Vol 311-313 ◽  
pp. 1182-1185
Author(s):  
Jie Li ◽  
Ai Hua Zhu ◽  
Heng Zeng ◽  
Jun Peng Li
Keyword(s):  
Control Strategy ◽  
Dynamic Load ◽  
Hybrid Control ◽  
Dynamic Performance ◽  
Active Suspension ◽  
Vehicle Dynamic ◽  
Damping Force ◽  
Joint Simulation ◽  
The Road ◽  
Car Model

In order to improve the road-friendliness of vehicle, this paper studies vehicle dynamic performance through establishing car model in ADAMS, hybrid control strategy in SIMULINK and the use of joint simulation technology. By using dynamic load coefficient and the road-friendliness index of dynamic load stress factor evaluate the road-friendliness of the semi-active suspension system with hybrid control strategy. The research shows that the road-friendliness will be better when the damping force distribution coefficient for 0.2 ~ 0.6.

Reducing Vertical and Angular Accelerations With Nonlinear Asymmetrical Shock Absorber in Passenger Vehicles

2013 ◽  
Author(s):  
Marcos Silveira ◽  
Bento R. Pontes ◽  
José M. Balthazar
Keyword(s):  
Shock Absorber ◽  
Ride Comfort ◽  
Nonlinear Characteristics ◽  
Passenger Vehicles ◽  
Car Model ◽  
Shock Absorbers ◽  
Nonlinear Shock ◽  
Angular Oscillations ◽  
Impact Absorption ◽  
Severity Parameter

The behaviour of linear and nonlinear shock absorbers are compared to diminish vertical and angular (pitch) accelerations of passenger vehicles, improving comfort by result. A 4-dof half-car model is used with three configurations of dampers: symmetrical, asymmetrical and front asymmetrical. The analyses use three standard road inputs and include variation of the severity parameter, the asymmetry ratio and the velocity of the vehicle. The comparison shows that the asymmetrical system, with nonlinear characteristics, tends to have a smoother and more progressive behaviour. The results show that the use of the front asymmetrical system diminishes angular oscillations of the vehicle. As lower levels of acceleration are essential for improved ride comfort, the use of asymmetrical systems for vibrations and impact absorption is a superior choice for passenger vehicles.

scholarly journals Experimental Researches on the Dynamic Behavior of the Magnetorheological Damper

2020 ◽  
Author(s):  
Alexandru Dobre
Keyword(s):  
Dynamic Behavior ◽  
Shock Absorber ◽  
Active Suspension ◽  
Suspension System ◽  
Magnetorheological Damper ◽  
Passenger Cars ◽  
Damping Force ◽  
The Road ◽  
Shock Absorbers ◽  
Road Profile

In the context of improving the comfort and dynamics of the vehicle, the suspension system has been continuously developed and improved, especially using magnetorheological (MR) shock absorbers. The development of this technology which is relatively new has not been easy. Thus, the first widespread commercial use of MR fluid in a semi-active suspension system was implemented in passenger cars. The magnetorheological shock absorber can combine the comfort with the dynamic driving, because it allows the damping characteristic to be adapted to the road profile. The main objective of the paper is to analyze the dynamic behavior of the magnetorheological shock absorber in the semi-active suspension. In this sense, the author carried out a set of experimental measurements with a damping test bench, specially built and equipped with modern equipment. The results obtained from the experimental determinations show a significantly improved comfort when using a magnetorheological shock absorber, compared to a classic one, by the fact that the magnetorheological shock absorber allows to modify the damping coefficient according to the road conditions, thus maintaining the permanent contact between the tire and the road due to increased damping force.

Sign in / Sign up

Export Citation Format

Share Document