Stability Control by Advanced Full-Braking Systems of Motorbike Vehicles

The continuously increasing traffic in European urban areas is rapidly stimulating the diffusion of 2-wheeled vehicles in spite of their higher accident risk. This increased risk is due to a large extent to the natural stability limitations of two-wheel vehicles, in particular the loss of the cornering force in curves has a much more dramatic effect as, for instance, in 4-wheel vehicles. This happens for instance during an exaggerated braking action in curves, so that ABS strategy may not simply concentrate on avoiding blocking the wheel but must also avoid overshoots which may lead to a transient, but very dangerous, loss of cornering force. Against this background, this paper proposes a curve safe ABS strategy for motorcycles which is based on three elements: a sensor extension, a tilt angle estimator and a cautious ABS control which takes into account the probable limit and limits the switching operation to a very small region in order to avoid a loss of cornering force. The strategy is developed using a software simulator in Matlab/Simulink tuned on measurements of a KTM Adventure 950 motorcycle.