A sideslip angle-free approach to vehicle stability assessment and control

This paper introduces a new approach for assessing vehicle stability using phase-plane methods that eliminates the need to measure or estimate sideslip angle. The β−r−β˙ phase space and the r−β˙ phase plane are proposed as tools to capture vehicle dynamics across varying conditions and tyre models, using a single-track vehicle model with adapted Fiala brush and simplified Magic Formula tyre models. A No Sideslip (NS) stability region, defined using only measurable variables – yaw rate (r), lateral acceleration (ay), and sideslip rate (β˙) – is introduced to isolate stable trajectories effectively. The NS stability region is applied in an Electronic Stability Control (ESC) design, benchmarked against a state-of-the-art (SOA) ESC that relies on sideslip angle. Results demonstrate the effectiveness in activating as required without performance loss. A fully NS ESC is developed and tested in a sine-with-dwell manoeuvre using VI-Grade CarRealTime, showing comparable performance to the SOA ESC. This study confirms that enhanced vehicle stability can be achieved without sideslip angle estimation, offering a practical solution for lateral stability control.