Research On Active Braking Based On Fuzzy Sliding Mode Control

One of the main performances of a car is its braking performance,and cornering braking is a more complicated condition.In this process,due to the existence of the centroid side yaw angle and the yaw rate,the lateral inertial force is caused,so that the vertical load of the vehicle is transferred from the inner wheel to the outer wheel;the vertical load is caused by the presence of the brake deceleration.Transferred by the rear wheel to the front wheel.Therefore,excessive steering is likely to occur,resulting in instability of the vehicle.In this paper,we briefly summarize,analyze and simulate some problems in the active braking process.Firstly,because the dynamic model is the premise and basis of the subsequent simulation research,the eight-degree-of-freedom vehicle model is established,and the vertical load expression of each wheel in the curve braking process is derived according to the corresponding dynamic equation;A magic tire model was established as a theoretical basis for analyzing side yaw,lateral force,slip ratio and braking force.Secondly,it analyzes and summarizes the dangerous situations that are easy to occur in the active braking process,and discusses the causes.Finally,in theory,we find out the preventive measures that can reduce the danger during the braking process.Furthermore,based on the stability parameters centroid side yaw angle and yaw rate,a synovial controller is established.The fundamental purpose is to apply a compensating braking force to the inner rear wheel or the outer front wheel during the braking process of the vehicle,and to correct the dangerous state in time.At the same time,a simple PID model was established,and the corresponding simulation work was carried out,and compared with the synovial controller.Finally,according to the content of this article,the experimental verification was carried out.First,the tracking condition(including fixed and variable values)of the desired brake pressure is verified in a hardware-in-the-loop manner.Second,The correctness of the model such as the working state of the ESP and the calculation of the expected brake pressure was verified by the actual vehicle test.