Sliding-mode based estimation of the safety margins of lateral forces in motorcycle cornering

This paper introduces an approach to estimate quantities of the motorcycle dynamics, focusing on lateral force margins, which are a safety critical information for driver assistance systems. Unlike prior work, it considers both out-of-plane and in-plane dynamics, taking into account the impact of pitch on turn rate measurements. An extended nonlinear model combined with a sliding mode approach is proposed. The observer is designed in transformed coordinates, using a method for inverting the transformation. A practical implementation concept is also presented that demonstrates real-world feasibility. The paper explains the calculation of the lateral force margins and their relation to the friction ellipse. The proposed observer concept is evaluated with simulation data.