A Vehicle Roll-Stability Indicator Incorporating Roll-Center Movements

In the development of active-passive roll control systems, a vehicle model that can represent realistic roll behavior is essential for predicting the impending rollover and for accurately applying the control force to avoid vehicle rollover. The vehicle roll center is a key parameter that influences the vehicle roll dynamics. Since the roll center movement becomes important as the vehicle roll angle increases, it is desirable to include this effect in the roll control system. This paper proposes a dynamic roll stability indicator (RSI) incorporating roll center movement that generates rollover threshold in terms of lateral acceleration. A robust parameter identification algorithm using a disturbance observer is designed to estimate the lateral and vertical roll center movements. These estimates are later used in the RSI to update the rollover threshold. The effectiveness of the proposed method is demonstrated through simulations, and its performance is compared with other rollover warning algorithms.