Three-axle Heavy-duty Vehicle Steering Brake Coordinated Control

Traffic safety has always been a topic of concern.When a vehicle is in the steering braking condition,the steering system and the braking system may have functional interference and coupling,which may cause traffic accidents.Heavy-duty vehicles are more prone to danger under steering braking conditions because of their long body and high center of mass.So it is crucial to solve these problems.Corresponding controllers,around this topic,were designed and verified by TruckSim-Simulink co-simulation and hardware-in-the-loop experiment.The main research are as follows:(1)The three-axis vehicle self-seeking optimal ABS controller was designed.The simulation and experimental results show that the braking time,braking distance and yaw rate of the self-seeking optimal ABS are smaller than the traditional ABS under the four working conditions,which indicates that the self-seeking optimal ABS improves the braking performance and stability under braking process of the three-axle vehicles.(2)The yaw mechanical properties of vehicle were analyzed,based on which the fuzzy rules of slip ratio allocation were formulated.In order to improve the safety performance of the three-axle vehicle,a cooperative controller for three-axis vehicle under steering braking condition was designed by differential braking method.Simulation and experimental results show that yaw rate,the centroid side angle,braking time and so on of the cooperative control are all less than ABS.It shows that the coordinated control improves the stability,braking performance and so on of the three-axle vehicles under steering braking condition.(3)A cooperative optimization controller was designed to improve the performance of the steering brake cooperative controller.Vehicle steering characteristic optimization identification method were used.The yaw mechanical properties of the vehicle were refined and analyzed.A control strategy that fully utilized the vehicle's yaw moment was developed.Self-seeking optimal braking algorithm was added.The simulation and experimental results show that the yaw rate,centroid angle,steering wheel angle and braking time of the cooperative optimization control are reduced compared with the cooperative control and ABS,indicating that the stability and braking performance of three-axle vehicles under steering braking conditions is improved by the collaborative optimization control on the basis of coordinated control.It is said that the self-optimizing ABS controller is simple and feasible,which can automatically search for the peak adhesion coefficient of the road surface.The steering braking cooperative controller theoretically analyzes the yaw mechanical characteristics.So it is feasible.The collaborative optimization controller can make full use of the vehicle yaw moment to ensure the stability of the vehicle.