| Electronic Stability Program(ESP)is an important control technology of vehicle active safety,it can help the driver to control vehicle dynamic characteristics.And it also can control the understeer or oversteer and limit yaw rate and sideslip angle in a stable range by regulating the wheel braking force and the output torque of the engine,so as to help the driver to drive in extreme conditions and prevent the car from the risk of instability.As people safety consciousness enhancement,the study of vehicle stability control system is of far-reaching significance.Firstly,in this paper,the basic principles of ESP was researched,the vehicle model with seven degrees of freedom,the nonlinear tire model based on "Brush" and the linear two degrees of freedom model were established by using MATLAB/Simulink and has carried on the simulation of model validation.And then to simplify structure and improve the efficient of the ESP control system under different tire-road friction coefficient,design the tire-road friction coefficient estimation algorithm based on Kalman filtering and least square method.Then through analyzing the theory of ESP control system,determine the state variables and expectations of the control system;Build the upper and lower two layers of stratified structure of the coordinated control system,then design the yaw rate controller and sideslip angle controller as well as the combination the two variables controller for vehicle stability control based on the theory of sliding mode control and the distribution solutions of single wheel braking torque at the lower controller.To build co-simulation platform based on Car Sim-MATLAB/Simulink,verify the correctness and effectiveness of the proposed control strategy through the simulation analysis of typical working conditionsFinally,The hardware in the loop test bench is built based on NI-PXI real time system,in order to verify the correctness of the proposed control strategy,the experiment was carried out on it. |
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