To solve the contradiction between model complexity and the warning accuracy of the algorithm of the vehicle rollover warning, a rollover state warning method based on the secondary predictive zero-moment point position for vehicles is proposed herein. Taking a sport utility vehicle(SUV) as the research object, a linear three-degrees-of-freedom vehicle rollover dynamics model is established. On the basis of the model, the lateral position of the zero-moment point and its primary and secondary rates of change are calculated. Then, the theoretical solution of time-to-rollover of the vehicles is deduced from the lateral position of the secondary predictive zero-moment point. When the rollover warning index, the lateral position of the zero-moment point, is greater than the set threshold, the active anti-rollover control system will be triggered. The active anti-rollover braking control system adopts a hierarchical control strategy. Taking the rollover warning index as the control target, the upper controller calculates the braking torque required by the front-outer wheel based on the Fuzzy Proportional Integral Derivative (PID) algorithm and the differential braking control strategy. The lower executive controller calculates the corresponding brake wheel cylinder pressure and inputs it to the corresponding wheel through the Electrical Hydraulic Brake(EHB), so that a certain additional yaw moment can be formed to prevent the vehicle from rolling over. Under some typical driving conditions, Carsim-Matlab co-simulation and real vehicle tests are carried out. The comparative test results show that the proposed rollover warning method based on the secondary predictive zero-moment point position can accurately and effectively predict the roll-over state of the vehicle, and the active anti-rollover braking control system can control the vehicle in time and effectively to prevent the vehicle from rollover.
