With the advent of serious attention to driving simulators, low speed tire modelling has become more important. This presents a numerical challenge to traditional formulations for longitudinal slip and slip angle. This paper presents a new formulation which differs from previous work in that both longitudinal slip and slip angle become state variables rather than kinematic functions of wheel spin rate and wheel velocity. The result is a model which: (1) yields traditional solutions at high speed; and (2) which comes to a stop in a reasonable way without numerical problems. The calculated longitudinal slip and slip angle can be paired with any semi-empirical tire model. Several challenging examples, including challenging examples, including braking-induced spinout ending in a stop on a severely inclined surface, illustrate the power of the new technique.
Samenvatting