Adams Car Package > Adams Car > Appendix > Special Requests > Vehicle Dynamics Parameters II

Vehicle Dynamics Parameters II

This routine outputs the front, rear, and percent total lateral load distribution as well as the front and rear axle slip and neutral steer angles. From these parameters, useful information such as cornering compliance's can be derived.
Input:
REQ/id, FUNCTION = USER (1131,lfid,rfid,lrid,rrid,swid,stbid,ratio,bcgid)
where:
 
 
Description
lfid
=
id of a MARKER on the sprung mass at the left front wheel center
rfid
=
id of a MARKER on the sprung mass at the right front wheel center
lrid
=
id of a MARKER on the sprung mass at the left rear wheel center
rrid
=
id of a MARKER on the sprung mass at the right rear wheel center
swid
=
steering wheel MARKER id used in revolute JOINT to body
stbid
=
body MARKER id used in revolute JOINT with steering wheel
ratio
=
overall steering system ratio (steering wheel turns per unit average toe angle)
bcgid
=
id of any MARKER on the body (i.e. 5100 is recommended)
Request File Output
Column Number Output:
1. Front total lateral load transfer (N)
2. Rear total lateral load transfer (N)
3. Percent of total lateral load transfer at front (%)
4. Front axle slip angle (deg)
5. Rear axle slip angle (deg)
6. Neutral steer at steering wheel (deg)
Notes on Input and Output
It is recommended to pass the wheel center rise MARKERs to this routine as parameters two through five. Adams Car will take this approach.
The equation used to calculate the axle slip angles is as follows:
Front Axle Slip = atan ( Vy / Vx ) - SWA / ratio
Rear Axle Slip = atan ( Vy / Vx )
where:
 
 
Description
Vy
=
lateral velocity at point on the body centerline at axle
Vx
=
longitudinal velocity at point on body centerline at axle
SWA
=
steering wheel angle
ratio
=
overall steering system ratio