Research Of The Key Technology Of Integrated Control Of EPS And ESP

In recent years automobiles have been popularized rapidly in the worldwide, and are becoming more and more intelligent and electronically. Electronic power steering system (EPS) and Electronic stability program (ESP) are the representatives of steering and braking electronic control system. The integrated control of these two systems is a hot topic in the research field. In the dissertation, the theoretical and experimental research is carried out to the integrated control of the vehicle EPS and ESP systems.The EPS and ESP systems’ development process is firstly reviewed, the two systems’ basic working principles are introduced, the recent research status nationally and internationally is concluded, and the research direction for vehicle chassis integrated control is put forward.According to the mechanical and electrical structure of the steering system, the input-output model of EPS system is built. Considering the requirement of steering light performance under in-situ steering and middle- and low- speed, and the handling control performance and road feeling under middle- and high-speed, the EPS multi-mode control strategy and method are designed. The modeling and simulation analysis are carried out under power assisting mode, reversal mode, damping mode and limp mode.According to the sensors’ configuration of integrated control, the road adhesion coefficient estimation method based on reversal torque is proposed, and the nonlinear observer is adopted for the observation of the vehicle longitudinal/lateral speed. When vehicle is under limiting instability condition, the bigger deviation is existed between the vehicle actual model and linear 2-DOF model. The ordinary linear controller could not achieve the optimal control performance. The yaw torque controller is designed by nonlinear H∞ control based on the output feedback.Based on analyzing the correlation of EPS and ESP, the layered integrated control framework is designed. Considering the coupling between the steering light performance and handling stability, the integrated control rules are designed by decision allocation, and the fuzzy control method is utilized to design the upper-layer decision controller for EPS/ESP integrated control system.The national and international driver-in-loop test beds are compared. The integrated system driver-in-loop test bed is based on the NI PXI and DYNAware. The veDYNA is applied to provide the 3-dimension environment, and the complete ’human-vehicle-environment’ closed-loop driving environment is constructed by DYNAanimation. The proposed EPS/ESP integrated control method is validated through the experiment on the integrated system driver-in-loop test bed constructed by our own and vehicle test. The results demonstrated that the integrated control has significant effect to improve the vehicle chassis comprehensive performance.