Non-Linear and Hysteretic Analysis of the Behaviour of Magnetorheological Dampers

Modeling of Magnetorheological Dampers Utilizing a General Non-linear Model

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x10391499 ◽

2010 ◽

Vol 22 (5) ◽

pp. 435-442 ◽

Cited By ~ 2

Author(s):

X.C. Guan ◽

P.F. Guo

Keyword(s):

Linear Model ◽

Magnetorheological Dampers ◽

Non Linear

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Driving Safety Improved with Control of Magnetorheological Dampers in Vehicle Suspension

Applied Sciences ◽

10.3390/app10248892 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8892

Author(s):

Piotr Krauze ◽

Jerzy Kasprzyk

Keyword(s):

Degrees Of Freedom ◽

Aerodynamic Drag ◽

Mr Damper ◽

Driving Safety ◽

Vehicle Body ◽

Control Algorithms ◽

Magnetorheological Dampers ◽

Vehicle Model ◽

Passive Suspension ◽

Non Linear

The article is dedicated to the control of magnetorheological dampers (MR) included in a semi-active suspension of an all-terrain vehicle moving along a rough road profile. The simulation results of a half-car model and selected feedback vibration control algorithms are presented and analysed with respect to the improvement of driving safety features, such as road holding and vehicle handling. Constant control currents correspond to the passive suspension of different damping parameters. Independent Skyhook control of suspension parts represents the robust and widely used semi-active algorithm. Furthermore, its extension allows for the control of vehicle body heave and pitch vibration modes. Tests of the algorithms are carried out for a vehicle model that is synthesised with particular emphasis on mapping different phenomena occurring in a moving vehicle. The coupling of the vehicle to the road and environment is described by non-linear tire-road friction, rolling resistance, and aerodynamic drag. The pitching behaviour of the vehicle body, as well as the deflection of the suspension, is described by a suspension sub-model that exhibits four degrees of freedom. Further, three degrees of freedom of the complete model describe longitudinal movement of the vehicle and angular motion of its wheels. The MR damper model that is based on hyperbolic tangent function is favoured for describing the key phenomena of the MR damper behaviour, including non-linear shape and force saturation that are represented by force-velocity characteristics. The applied simulation environment is used for the evaluation of different semi-active control algorithms supported by an inverse MR damper model. The vehicle model is subjected to vibration excitation that is induced by road irregularities and road manoeuvres, such as accelerating and braking. The implemented control algorithms and different configurations of passive suspension are compared while using driving-safety-related quality indices.

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B. The Non-Linear Calculations for Pulsating Stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900019008 ◽

1967 ◽

Vol 28 ◽

pp. 105-176

Author(s):

Robert F. Christy

Keyword(s):

Major Part ◽

Afternoon Session ◽

Discussion Session ◽

Pulsating Stars ◽

Fourth Symposium ◽

Non Linear ◽

Considerable Discussion ◽

Informal Approach ◽

Preceding Session

(Ed. note: The custom in these Symposia has been to have a summary-introductory presentation which lasts about 1 to 1.5 hours, during which discussion from the floor is minor and usually directed at technical clarification. The remainder of the session is then devoted to discussion of the whole subject, oriented around the summary-introduction. The preceding session, I-A, at Nice, followed this pattern. Christy suggested that we might experiment in his presentation with a much more informal approach, allowing considerable discussion of the points raised in the summary-introduction during its presentation, with perhaps the entire morning spent in this way, reserving the afternoon session for discussion only. At Varenna, in the Fourth Symposium, several of the summaryintroductory papers presented from the astronomical viewpoint had been so full of concepts unfamiliar to a number of the aerodynamicists-physicists present, that a major part of the following discussion session had been devoted to simply clarifying concepts and then repeating a considerable amount of what had been summarized. So, always looking for alternatives which help to increase the understanding between the different disciplines by introducing clarification of concept as expeditiously as possible, we tried Christy's suggestion. Thus you will find the pattern of the following different from that in session I-A. I am much indebted to Christy for extensive collaboration in editing the resulting combined presentation and discussion. As always, however, I have taken upon myself the responsibility for the final editing, and so all shortcomings are on my head.)

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