Research On Vehicle Stability Control Based On Steady Maps Of Achievement Performance

In the course of nearly a hundred years of development of the automobile industry,vehicle stability control technology has always been the focus of academic and industrial research,and many chassis electronic control systems have been derived from it.Since it is difficult for a single control method to meet the overall handling stability requirements of the vehicle with high coupling and multiple directions,the coordinated control between various chassis electronic control systems has become an inevitable trend in the development of active safety technology.This paper takes Direct YawMoment Control(DYC)and Active Front Steering(AFS)as the research objects,introduces the steady map of achievement performance and proposes a vehicle driving stability judgment Then,the intervention weights of AFS and DYC are allocated with the lateral acceleration of the vehicle as an index,and finally the effectiveness of the coordinated control strategy under different working conditions is verified through simulation experiments.The main points are below:Several vehicle dynamics models were established in MATLAB/Simulink based on the magic formula tire model.In Carsim,the co-simulation experiment is completed by taking the fishhook input as an example,and the comparison of the state-response curves proves that the established dynamic model can accurately reflect the driving state of the vehicle.The steady map of achievement performance is introduced and a vehicle driving stability judgment method is proposed based on the front wheel angle.The drawing methods of the "front wheel turning angle-longitudinal vehicle speed" map of achievement performance and the "mass center slip angle-longitudinal vehicle speed" map of achievement performance are introduced by formula derivation,and the steady map of achievement performance is further obtained by combining the tire cornering characteristics and road adhesion constraints.In this way,the maximum stable value of the front road corner at different times can be obtained.By comparing the actual value of the front wheel angle with the stability critical value,it is possible to quickly judge whether the vehicle is currently stable or not.The merits and demerits of the phase plane diagram and Lyapunov’s second theorem method in dividing the vehicle driving stability domain are compared and analyzed,and it is pointed out that the steady state reachable domain diagram can timely and accurately predict the stable state of the vehicle in the driver input stage.The feasibility of the steady map of achievement performance is proved by simulation experiments.Interventional guidelines for AFS and DYC were designed and validated.Taking longitudinal vehicle speed and front wheel angle as objects,the intervention criteria of AFS and DYC are formulated,and the weight factor expression is designed with lateral acceleration as the index.The AFS and DYC executive controllers are designed based on the sliding mode variable structure control theory,which are respectively used to calculate the additional front wheel angle and wheel braking torque required to maintain vehicle stability.Build the controller model in MATLAB/Simulink and verify its effect by simulation under different road adhesion conditions.The results show that the intervention criterion proposed based on the steady map of achievement performance can effectively synthesize the effect of AFS and DYC,and can ensure the stability of the vehicle.It can effectively improve the ride comfort while driving.