H∞ control of anti-rollover strategy based on predictive vertical tire force

Abstract

The mainstream rollover evaluation index, lateral load transfer rate (LTR), is commonly used in the rollover control field. However, it is not instant enough to reflect the rollover tendency since it can only reflect the load transfer rate of one side wheels while single rear wheel leaves the ground first during rollover happens. In order to monitor the rollover tendency more instantly and improve the reliability of anti-rollover control system, a new evaluation index called predictive vertical tire force (PVTF) is proposed, which is based on the single vertical tire force and merges both iterative prediction and derivative prediction methods. Meanwhile, an optimization is taken to solve the contradiction between prediction time and deviation. Secondly, using the PVTF as the measurement output, an anti-rollover control system based on active steering is established in this paper. In order to achieve the desired tracking effect and anti-jamming capability, a two-way H∞ controller is adopted in the anti-rollover control system. Lastly, the simulation results of J-turn condition and NHTSA (national highway traffic safety administration) condition are conducted and the results indicate that the anti-rollover control system has strong stability and robustness. Meanwhile, benefit from the pre-warning function of PVTF, the controller is triggered earlier and the vertical tire forces of four wheels are controlled to be positive all the time, which is beneficial for handling stability.