Roll Stiffness Optimization for Anti-roll Bar in Interconnected Air Suspension

Lateral Interconnected Air Suspension (hereinafter referred to as Interconnected Air Suspension or IAS) tends to deteriorate vehicle roll stability on the condition of steering while travelling in high speed, so interconnection state is generally closed when lateral acceleration of car body exceeds its designed threshold (0.4 g in this paper). In this paper, a roll stiffness optimization strategy of anti-roll bar in IAS based on genetic algorithm is proposed for better roll stiffness as well as better roll angle vibration characteristics both in the state of interconnection and non-interconnection. And the strategy is used to optimize the anti-roll bar of a passenger car equipped with IAS. In the optimization strategy, weighted sum of body roll angle's mean value and standard deviation is originally determined as the objective function based on impact sensitivity analysis, i.e. the analysis of anti-roll bar roll stiffness's influence on body roll angle's mean value and standard deviation. Besides, totally 6 driving conditions are considered in the optimization to make it more realistic. The optimization result shows that optimal roll stiffness of front and rear anti-roll bar is 1998 N.m/deg and 1402 N.m/deg respectively. The proposed optimization strategy helps to resolve the problem of how to balance vehicle roll stability and roll angle vibration characteristics under different working conditions during the process of anti-roll bar roll stiffness matching for IAS vehicles. It can also be guidance or a reference for the matching of other parameters in IAS vehicles.