Effect of Roll Motion Control on Vehicle Lateral Stability and Rollover Avoidance

This paper discusses the effects of the roll control on the vehicle performance. Rollover avoidance and lateral stability constitute the core analysis of this paper. Two roll reference generators, one static (towards zero) and one dynamic (function of the vehicle lateral acceleration) are designed for control purpose. Roll motion control is achieved through the generation of a feedback roll moment. To track the static roll reference, the roll moment can be allocated to the active suspensions, the semi-active suspensions, or the active antiroll bar, while the roll motion control towards the dynamic reference can be only achieved using the active suspensions. To do so, firstly, based on the time-domain equations of motion of the full-vehicle nonlinear model, a study on how the roll control can help the vehicle to avoid the rollover without deceleration or steering actions is done. Secondly, a frequency analysis of the lateral stability response to the steering input, with and without roll motion control is performed to extract the ranges of steering frequencies and amplitudes where the roll control could be useful. For this study, two lateral-roll linear time invariant vehicle models (without and with linear quadratic roll control) are compared. Thirdly, two robust roll controllers, i.e., Lyapunov-based, and super-twisting sliding mode are developed, validated and compared on the full vehicle nonlinear model using Matlab/Simulink. This paper also provides a comparison between the roll angle control towards the static and the dynamic references.