Research On Vehicle ESP Control Strategy And Integrated Control Based On ABS And ESP

The stability of vehicle is an important factor affecting vehicle safetyperformance, with the gradually improvement of automobile chassis system anddevelopment of computer technology, research on electronic control system aimed atvehicle stability has become a hot spot. How to effectively and rationally coordinatethese subsystems and eliminate the interference of each subsystem is industrydevelopment trend nowadays. The paper chooses ABS and ESP as typical of the studyon vehicle stability and coordination control.Electronic Stability Program(shortened as ESP) can not only prevent vehicle fromentering unstable working area, but also assist vehicle rapidly return to stability whenthe vehicle has been unstable. Anti-lock braking system (ABS) can significantlyimprove the braking stability of the vehicle during emergency braking conditions andprevent the vehicle from skidding, Sharp and other dangerous conditions. Becausemutual interference will produce if two subsystems operate simultaneously, thereforethe coordination of both is quite necessary. Through reasonable integrated control, thebraking distance can be shortened, and at the same time the vehicle’s directionalstability can be improved. Therefore the research on ESP control strategy and theintegrated control based on ABS and ESP has important significance.First, the paper analysis the inside structure of one hydraulic system based onvehicle ESP hydraulic schematics, the AMEsim structure model of Hydraulic unit isidentified using physical modeling methods. Through the study of automotive systemdynamics, Matlab/Simulink model with fifteen degree of freedom, including thenonlinear tire model, wheel rotation mechanical model, steering system model andsuspension model are identified, the vehicle reference model are set up on this basis.Through theoretically research on vehicle stability, the paper chooses the yaw rate andthe slip angle as control variables, yaw rate tolerance band and Sideslip angle phase plane as the methods to determine vehicle states and select the differential side brakeas the way of brake force distribution, then establishes a two-dimensional ESP fuzzycontroller. Through a large angle in the steering emergency double lane changesimulation on the low friction coefficient road with high speed, verifies theeffectiveness of ESP control strategy.The ABS controller is designed based on PID control algorithm and takes slip rateas the control variables, and do ABS simulation experiment in the high, low frictioncoefficient road and joint road, the simulation result proves the designed ABS caneffectively control the wheel slip rate and prevent the wheels from locking. The impacton the stability of the vehicle when the ABS system and ESP systems worksimultaneously is analyzed combined with the chassis integrated control theory. Acoordination controller is programmed which can ensure vehicle stability and brakingstability simultaneously, coordinated intervention time and control efforts of the ABSsystem and the ESP system. The coordination controller is simulated in high-speedcornering brake condition, through comparison of the simulation results of with andwithout the coordination controller, the conclusion is the designed integratedcontroller can produce effective role in driving stability and braking stability of thevehicle under dangerous circumstance.