Vehicle Dynamics and Stability Analysis with Matlab and Adams Car

汽车英语文献

Vehicle Dynamics and Stability Analysis

with Matlab and Adams Car

N.Arborio, P.Munaretto, M.Velardocchia

Dipartimento di Meccanica Politecnico di Torino

C.so Duca degli Abruzzi, 24 – 10129 Torino Italy

Tel: +39 011 5646931; fax: +39 011 5646999: email: velardocchia@polito.it

N. Riva, E. Suraci

FIAT Auto - Direzione Tecnica Autotelaio

C.so Settembrini, 40 – 10135 Torino - Italy

ABSTRACT

The automotive active dynamics and stability control is nowadays available from manymanufacturers which offer different hardware and software solutions. To compare theperformance obtainable considering different active systems, a mathematical model of anew car was implemented through Adams Car. The model was completed with apowertrain specifically conceived in Matlab environment to overcome problems due toan Adams Car modelling not suitable to describe every operating condition (e.g.standing start, gearshift).

A strategy to overcome the problems introduced by the dependence of nominal yaw ratevalue on the instantaneously available tire-terrain adhesion coefficient was considered.The most important results obtained adopting the described strategy are presentedthrough animations.

INTRODUCTION

Many Authors described how active systems could increase handling and comfort car’sperformance. Active steering systems, vehicle dynamics control, continuous dampercontrol are an immediate example of active systems nowadays available. From carmanufacturer’s point of view, such large availability requires to increase the know-howboth about the active systems and their integration. Great importance acquires,moreover, the capability to compare the performance obtainable considering differentactive systems. To develop the necessary evaluation, it is particularly useful to employsoftware that permits to manage a sensitivity analysis. With this aim, a mathematicalmodel of a new FIAT automobile was implemented through the Adams Car code.Adams Car 10.0 permits to simulate a lot of different manoeuvres, but presents somelimits when has to model the torque transmitted by clutch, synchroniser, brakes,considering operating conditions that require a continuous change of the slippingvelocity sign. During transients that determine those changes, oscillations appear due toa discontinuous model of friction transmitted torque. To overcome such limit, extendingthe Adams Car ability to model the vehicle dynamics also including active systems, themodel was completed with a powertrain specifically conceived in Matlab environment.The driveline conceived permits to simulate, for example, operating condition likestanding start and gearshift, and to consider correctly the wheel’s dynamics duringmanoeuvres typical of vehicle dynamics control (VDC).