Research On Fuzzy Control Strategy For Automobile ESP Based On Phase Plain Analyzing

China’s auto production and sales volume has reached the first of the world. It bringsconvenience and comfortable to us, but also binging a lot of society problem. Among these,the safety of automobile driving is one of the most important problems. The arising of theElectronic Stability Program（ESP） has effectively improved the vehicle yaw stability. So itcould keep the vehicle driving stability, especially when the vehicle turning in high speed.The centre of the ESP control system is the control strategy. Therefore it is necessary toresearch the ESP control strategy deeply.To better research the ESP control strategy, first we do phase plain analyzing.Through simulation, we can get the vehicle side-slip angle （β） and yaw rate （r） phase plain,also the vehicle side-slip angle （β） and vehicle side-slip angular velocity （β&） phase plain.On the basis of the conclusion of the phase plain analyzing, the fuzzy control system isdesigned. And do research on the fuzzy control strategy. There are five chapters in thisdissertation. The main contents of these are as follows:In Chapter One, The composition and working theory of the vehicle ESP control systemare briefly introduced, as the same the history and the status of development. Many ESPcontrol method at home and abroad are introduced. Meanwhile the Fuzzy Control Strategyfor Automobile ESP is also put forward.In Chapter Two, three vehicle models are built for the simulation. Firstly, the2-DOFvehicle model is built as the reference model of ESP, which is used to describe the desiredvehicle moving state. And the desired yaw rate is calculated by the2-DOF vehicle model.Secondly, the4-wheel and3-DOF vehicle model as the simple model of ESP phase plainanalyzing is built. Through3-DOF vehicle model simulating with ESP or not, analyze theβ rphase plain and β β&phase plain. And it is very important to analyze the degree ofconvergence using different ESP control method. Finally the complex nonlinear vehicle dynamic model is built with the ve-DYNA software to design the ESP fuzzy control system.In Chapter Three, phase plain is analyzed using the4-wheel and3-DOF simple vehiclemodel. Two kinds of ESP control strategy are analyzed with the phase plain analyzing: onestrategy is following the desired yaw rate（r method）, the other strategy is restraining theside-slip angle（β method）. On the basis of the β rphase plain with control or not, thecontrol result of the desired yaw rate following strategy is analyzed. And through phase plainanalyzing of PID control parameter setting, P control method is chosen as the one of thecontrol methods of this dissertation. Then analyze the phase plain with the P control ofdesired yaw rate, to study convergence degree of the phase plain with different value ofproportional gainK_pr. The law ofK_prand convergence degree of the phase plain couldsummarized through these. On the basis of the β β&phase plain with control or not, thecontrol result of the side-slip angle restrain strategy is analyzed. P control method is chosenas the one of the control methods of this dissertation. Then analyze the phase plain with the Pcontrol of side-slip angle, to study convergence degree of the phase plain with different valueof proportional gainK_pβ. The law ofK_pβand convergence degree of the phase plaincould summarized through these. Finally, Though phase plain analyzing of the two kinds ofESP control strategy, compare the difference of the two methods.In Chapter Four, the complex nonlinear vehicle dynamic model is built with theve-DYNA software to design the ESP fuzzy control system. The ESP fuzzy control system isdesigned with the combination control of r method and β method. Andλ_β is the scalefactor of the β method in the combination control. The fuzzy controllers ofK_pr,K_pβandλ_β are designed by the law of the phase plain analyzing in Chapter Three. Thesimulation of the ESP fuzzy control strategy is did in the environment of ve-DYNA software.The simulation of high adhesion conditions uses the method of NHTSA FMVSS126regulation’s evaluation of ESP. The simulation of low adhesion conditions uses the methodof GM’s evaluation of ESP. And other simulation of the ESP fuzzy control strategy is did asopposed to other control statagy. The simulation results validate that the Fuzzy ControlStrategy for Automobile ESP built in this dissertation could improve the vehicle yaw stability very effectively.In Chapter Five, summarizes and conclusions are expressed, and the future researchdirection is indicated.