The Controller Design Of Commercial Vehicle EPS Based On Fuzzy Adaptive PID

Electric Power Steering System (EPS) is a new type steering system. It has the advantages of saving fuel, producing less pollution, improving vehicle's handling stability, driving comfort and security, besides, it can adjust the characteristics of power steering and benefit environment protection. As a new-high-tech that follows modern vehicle development topic closely. EPS will be the inevitable direction for automobile power steering.The dissertation selected a certain medium truck loading 4T as the equipped target models of electric power steering system of commercial vehicle, and developed MC9S12DG256 processor as the core of the controller. Designed the controller based on considerations of characteristics of commercial vehicle. Designed EPS system overall layout, chose principal electronic components according to the steering system structure of the chosen vehicle, designed 24V,12V,5V DC stabilized source, DC brush motor drive circuitry, clutch and relay control circuitry, signal processing circuitry, trouble detect circuitry and tabulated fault code. Accomplished normal power steering mode, damping power steering mode and aligning power steering mode based on the assist characteristic curve. Used fuzzy adaptive PID control method in the control of power steering. Chose proper membership functions and tabulated fuzzy control rules. Programmed corresponding fuzzification procedure, fuzzy inference procedure and defuzzification procedure. designed system self-safety inspection progress, clutch and relay fault type detect progress, A/D convert progress, anti-impulse interference mean shift filtration progress and power steering mode selection progress and so on. The intention can be basically fulfilled by debugging both the hardware and software.