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A variation in the camber of an automotive wheel is desired to compensate a side-slip force change owing to normal load transfer when the car is cornering. The camber of a steered wheel can be varied by adjusting caster or lean angle which are the representations of steering axis orientation. Thus, a smart camber can be created by a variable caster or lean angle. Choosing which parameter among the two angles to be variable is very important and dependent on its different effects. Here, homogeneous transformation is employed to establish camber as a function of caster, lean angle, and steering angle in the general case. A comparison between caster and lean angle based on different criteria is then made. The comparison shows that a variable caster is much better and more feasible than a variable lean angle in generating a smart camber.

As long as a tire steers about a titled kingpin pivot, the point coming in contact with the road moves along its perimeter. This movement affects the determination of kingpin moments caused by the tire forces, especially for large steering angles. The movement, however, has been neglected in the literature on the steerable-tire-kinematics-related topics. In this investigation, the homogeneous transformation is employed to develop a kinematic model of a steering tire in which the instantaneous ground-contact point on the tire is considered. The moments about the kingpin axis caused by tire forces are then computed based on the kinematics. A four-wheel-car model is constructed for determining the kingpin moment of steering system during the low-speed cornering maneuver. The result shows that the displacement of the ground-contact point along the tire perimeter is significant for large steering angles.