Adams Car Package > Adams Car > Appendix > All About SVC (Static Vehicle Characteristics) > Roll Center Height

Roll Center Height

Height at which a lateral force on the sprung mass, applied in the plane of the wheel centers, does not produce any suspension roll.

Computed by:

SVCROL

Input Variables Used:

■Compliance matrix
■Left and Right Wheel Center Markers
■Ground Height wrt global origin

Method:

The compliance matrix at the wheel centers are transferred to equivalent compliance matrix at the contact patch location. Now the left side vertical displacement is
      DZ_L = CP(3,3) - CP(3,9)
      DY_L = CP(2,3) - CP(2,9)
      YL
      ZL
Where:
 
DZ_L
- Vertical Displacement at left tire patch due to unit opposing force at left and right tire patch.
DY_L
-Lateral Displacement at left tire patch due to unit opposing force at left and right tire patch.
YL
- Lateral wheel center position wrt to ground.
ZL
- Vertical wheel center position wrt to ground.
Similarly for right side:
DZ_R = CP (9,9) - CP(9,3)
DY_R = CP (8,9) - CP(8,3)
YR
ZR
The equation of lines through the instant centers of left and right contact patches are:
0 = dz_l*( z - zl ) + dy_l*(y - yl)
0 = dz_r*( z - zr ) + dy_r*(y - yr) 
dz_l*zl + dy_l*yl = dz_l*z + dy_l*y 
dz_r*zr + dy_r*yr = dz_r*z + dy_r*y
The intersection of these two lines (if it exists) is the roll center location.
Apply Cramer's rule:
DET = ( DZ_L*DY_R - DZ_R*DY_L )
B1 = ( DZ_L*ZL + DY_L*YL )
B2 = ( DZ_R*ZR + DY_R*YR )
RC_VERT  = ( B1*DY_R - B2*DY_L ) / DET
Where RC_VERT is the roll center height.
Roll Center Height