Automobiles - Vehicle_Dynamics(21)

VehicleDynamicsFHRegensburg,UniversityofAppliedSciences

Withtheaccordingapproximationforthecosine-function

rS1

=cos =1 2or 2=2r02

one nallygets

rS

1

r0

(2.7)

rD=r0

remains.

11

3

rS1

r0

=

21r0+rS33

(2.8)

TheradiusrDdependsonthewheelloadFzbecauseofrS=rS(Fz)andthusisnamed

dynamictireradius.Withthis rstapproximationitcanbecalculatedfromtheundeformedradiusr0andthesteadystateradiusrS.By

vt=rD

(2.9)

theaveragevelocityisgivenwithwhichtreadparticlesaretransportedthroughthecontactarea.

2.2.2ContactPoint

Thecurrentpositionofawheelinrelationtothe xedx0-,y0-z0-systemisgivenbythewheelcenterMandtheunitvectoreyRinthedirectionofthewheelrotationaxis,

Fig.2.3.

Figure2.3:ContactGeometry

Theirregularitiesofthetrackcanbedescribedbyanarbitraryfunctionoftwospatialcoordi-nates

z=z(x,y).(2.10)

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