Adams Car Package > Adams Car > Appendix > All About SVC (Static Vehicle Characteristics) > Overall Steer Ratio

Overall Steer Ratio

The rate of change of steering wheel angle with respect to the change in average steer angle of a pair of steered wheels. Steer ratio is only computed for the front suspension.

Computed by:

SVCFST

Input Variables Used:

Compliance matrix
Steering box ratio (SRATIO)

Method:

SVC computes the steering change due to a Y force at the Pitman arm marker for pitman type steering or at the rack marker for rack type steering:
DSTEER = abs( C( 6,14 ) + C( 12,14 ) ) / 2
Pitman:
SVC assumes that the Pitman arm is oriented such that a Y force will turn the wheels. In addition, there must be some compliance at the Pitman arm in order to generate steer. The total Pitman arm angle change due to a Y force at the Pitman arm marker is:
DPIT=SQRT([C16,14]^2+[C17,14]^2+[C18,14]^2)
The overall steer ratio is:
Steer ratio = SRATIO DPIT / DSTEER
Rack:
SVC assumes that the rack is oriented such that a Y force will turn the wheels. In addition, there must be some compliance at the rack in order to generate steer. The total rack displacement due to a Y force on the rack marker is:
DRAC = C( 14,14 )
The overall steer ratio is:
Steer ratio = * DRAC / DSTEER / SRATIO
Overall Steer Ratio