An Investigation of a Road-Vehicle Directional Behavior Under Steady-State Conditions

Lukowski, S. A.; Fiedler, Robert; Claar, Paul W.

doi:10.4271/911872

Cited by 3 publications

(4 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In reality, the influence of the moment of inertia requires further investigation. Starting from equation (2) and (3), elimination of the lateral velocity V yields the following homogeneous equation for the yaw rate r : (6) where,…”

Section: The Dynamic Normalised Yaw Impulsementioning

confidence: 99%

See 1 more Smart Citation

On the objective assessment and quantification of the transient-handling response of a vehicle

Mavros

2007

Vehicle System Dynamics

View full text Add to dashboard Cite

The paper suggests a new methodology for the objective assessment and quantification of the response of a vehicle subjected to transient handling manoeuvres. For this purpose, a non-dimensional measure is defined, namely the normalised yaw impulse.This measure appears in two variations. In its general or dynamic form, it represents the difference between the yaw moment due to the front tyre forces and the yaw moment due to the rear tyre forces, divided by the sum of the aforementioned yaw moments. By employing a linear, 2 degree-of-freedom bicycle model it is shown that the general form of the normalised yaw impulse can be written as a function of the steer angle and the forward, lateral and yaw velocities of the vehicle. This form is referred to as the kinematic yaw impulse. It is demonstrated that the combined application of the dynamic and kinematic expressions of the yaw impulse not only facilitates the explicit assessment and quantification of the transient behaviour of a vehicle, but also reveals the influence of parameters such as the yaw moment of inertia, which traditionally leave the steady-state behaviour unaffected. provides a rather informative image of a vehicle's handling qualities and can be also related to the transient response of the system, as is well known from basic dynamics and control theory [8]. For example, the inverse of a specified bandwidth frequency can be used as an equivalent time constant for the vehicle's yaw rate response to a step-steer input [7]. Furthermore, the existence of a resonance frequency indicates a system with sub-critical damping, which is related to under-steer [2], as opposed to over-steering vehicles which are characterised by an equivalent damping ratio greater than one [2]. KeywordsNevertheless, the general characterisation of a vehicle based on its frequency response should be attempted with caution. For instance, an observed resonance frequency which indicates under-steer, might be related to the roll frequency of the vehicle in conjunction with a suspension set-up which dictates severe lateral weight transfer at the front end only. Certainly, this condition would not apply on any manoeuvre and thus the overall characterisation of the vehicle proves to be a difficult mission.The frequency response of a vehicle has already been related to its transient response to zero. This is easily explained if one considers the fact that under steady-state conditions 7 the yaw acceleration and consequently the yaw moment (the numerator in equation (1)) converge to zero, while the denominator converges to a non-zero value.The behaviour of the dynamic normalised yaw impulse is investigated further by implementing a linear 2 degree-of-freedom bicycle model. Assuming a constant forward speed U , sufficiently small steer angles and linear tyres, the equations of motion for the lateral and yaw degrees of freedom of the model read:Further assuming a front-steered vehicle and relatively small slip angles f a and r a , the following relations apply [2]:Equations (2) and (...

show abstract

Section: The Dynamic Normalised Yaw Impulsementioning

confidence: 99%

“…In this case, a vehicle is explicitly characterised based on the slope of the normalised acceleration curve. A very similar approach for the assessment of steady-state handling is employed by Lukowski et al [6].…”

Section: Introductionmentioning

confidence: 99%

On the objective assessment and quantification of the transient-handling response of a vehicle

Mavros

2007

Vehicle System Dynamics

View full text Add to dashboard Cite

show abstract

“…It was shown that the vehicle caji become highly oscillatory and even unstable. Lukowski et al [43] Einalyzed the steady-state behavior of a front wheel steered vehicle with steering dynamics.…”

Section: Free Steering Control Of An Automobilementioning

confidence: 99%

A methodology to investigate automobile handling and stability

Samsundar

View full text Add to dashboard Cite

INFORMATION TO USERSThis manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandard margins, and improper aligimient can adversely aflEect reproduction.In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.

show abstract

“…Assim, como vários parâmetros influenciam a resposta do veículo, é necessário a utilização de modelos adequados para capturar as características da resposta direcional do veículo, e também, a elaboração de métodos para a análise dos resultados do processo experimental, possibilitando ao engenheiro alterar algumas de variáveis e avaliar seus efeitos (LEE et al, 1996;LUKOWSKI et al, 1991). A modelagem proposta engloba todos os aspectos do movimento do veículo, incluindo os elementos dos subsistemas de suspensão e de esterçamento.…”

Section: Comeunclassified

Modelagem e análise da dinâmica lateral de veículos automotivos

Pasquini Junior

View full text Add to dashboard Cite

An Investigation of a Road-Vehicle Directional Behavior Under Steady-State Conditions

Cited by 3 publications

References 1 publication

On the objective assessment and quantification of the transient-handling response of a vehicle

On the objective assessment and quantification of the transient-handling response of a vehicle

A methodology to investigate automobile handling and stability

Modelagem e análise da dinâmica lateral de veículos automotivos

Contact Info

Product

Resources

About