Anti-rollover Control Of Vehicle Based On Chassis Dynamics

Vehicle rollover is a hot topic in the research field of active safety.Many researches have been published on vehicle rollover dynamics and anti-rollover control.While,in these studies,the effects of actuator on the rollover dynamics were ignored,which are very important to the characteristics of vehicle rollover stability.In this paper,taking the influence of brake system and active anti-roll bars into consideration,the dynamic models of vehicle rollover and some chassis system are established,including electro hydraulic braking(EHB),active steering(AS)and active anti-roll bar system.From the models,the anti-rollover control strategies of integrated chassis dynamics are proposed by using the sliding mode control method,which is optimized by fuzzy control theory.Also,to validate the models and the control strategies,some experiments and simulations are carried out under typical conditions.The results show that these models and control strategies are beneficial to the application in real vehicles.Firstly,vehicle rollover model and some chassis subsystem models are established.Considering the coupling relationship between roll motion and lateral motion,a three-degrees-of-freedom rollover model is built.Then,the steady-state Eigen value method and genetic algorithm are used to estimate the steady-state and transient parameters of the models.Also,the dynamic models of EHB system and active anti-roll bar are developed and validated by a test bench of EHB and Carsim software respectively.Secondly,some anti-rollover control strategies based on chassis subsystem are designed,including a slide mode control based active steering system,a slide mode control based EHB system,and a PID control based active anti-roll bar.Vehicle rollover stability and lateral stability of the application of these control strategies are simulated and analyzed,and results are compared.Finally,an anti-rollover control strategy of integrated chassis subsystem is proposed.According to the results of simulation and analysis of each anti-rollover control based chassis subsystem,an integrated anti-roll control strategy of active steering and active anti-roll bar and an integrated anti-roll control strategy of active steering and differential braking are designed respectively.Furthermore,a layered anti-rollover control strategy which integrates active steering,differential braking and active anti-roll bar is established.Also,vehicle rollover stability and lateral stability ofthe integrated controls are simulated in typical operating conditions.Then the advantages and disadvantages of each integrated control strategy are illustrated in the paper.