Dynamics And Active Safety Control Of The Tire Blowout Vehicle

The risk of tire blowout is very high and unpredictable.After tire blowout,there will be obvious yaw,go off the course,even tail-tail,swing,etc.,which seriously threaten the life and property safety of the driver and passengers.Due to psychological stress and lack of driving experience,it is difficult for the driver to make accurate and effective response in time,and often excessive operation or even wrong operation.At present,the active control of tire blowout vehicle is still unequipped to the chassis integrated active safety control system.On the basis of the existing active safety control system,this paper extends the active safety control of the tire blowout vehicle through the differential braking and the active front steering system.The following work has been carried out in detail:According to the change of tire pressure and characteristic parameters during tire burst,the tire blowout model is established based on Dugoff tire model.And the dynamic model of eight degree of freedom tire blowout vehicle model is established.Based on the active suspension system,the distribution of the vertical load of the car after the blowout is analyzed,and the mathematical model of the vertical mechanics of each wheel is derived.Taking straight and turning as examples,the dynamic response and tire mechanical changes of tire burst vehicle in different positions were simulated and analyzed respectively.And the characteristics of vehicle dynamic response of tire blowout vehicle in different conditions and different positions were summarized.According to the requirements of the control system,a two-degree-of-freedom vehicle reference model is established.and the constraint boundary of each target variable is determined.In view of the particularity of burst tire,the threshold of the burst tire is explained in detail.The wheel braking logic of the control system and the differential braking control system based on sliding mode control algorithm are designed.The tire burst in different position is verified under straight and turning conditions.The result shows that: The active control system designed in this paper can improve the yaw and safety performance of the vehicle on the premise of ensuring the stability of the vehicle.In order to further improve the deviation correction ability of the controller and increase the margin of the control system,a coordinated control strategy of differential braking and active front wheel steering integration is proposed.The active steering model is established,and the active steering control system is designed.The fuzzy controller is used to coordinate the two actuators in order to reduce the influence of the external environment in the vehicle control process and to improve the dynamic stability margin of the tire burst vehicle.The comparative simulation results show that: The differential braking and active steering coordinated control strategy proposed is better than single differential braking control,and the trajectory tracking ability improved,as well as higher stability margin.