Design of an integrated control system to enhance vehicle roll and lateral dynamics

Besides lateral instability, one major threat to all ground vehicles, especially SUVs, is the danger of rollover during cornering. A coordination strategy based on fuzzy logic has been devised to coordinate the sub-controls; namely, active steering, active differential, active brake and a novel active roll control system. Independent study of each sub-control as well as an analysis of their inter-relationship has been carried out. The coordination strategy is supposed to resolve the conflict among control targets – which are sideslip regulation, yaw rate tracking, lateral acceleration tracking and roll motion control – all of which are to be done while maintaining the driver’s desired longitudinal acceleration. Thus, a compromise must be reached. Vehicle sideslip angle and yaw rate were considered to be the criteria for lateral stability; and a combination of roll angle, roll rate and lateral load transfer was selected as the criterion for roll stability. The results of simulations on two SUV models in CarSim software indicate that the integrated controller can successfully restore vehicles’ stability in critical condition