Research On Fuzzy Control Strategies Of Commercial Vehicle EPS System

Electric Power Steering System (EPS system) is one of the research hot spot, high and new technologies of the modern automobile development. It not only enhance the operation stability, but also and the travel security in the automobile travel process, moreover the assist control is easy to adjust, save energy and protect the environmental, easy to mantian the service is convenient. Electric Power Steering System has already gradually became the tendency of the power steering technological development.The paper selected a medium-duty truck which can load four tons as the equipped target models of EPS system of commercial vehicle, according to the research vehicle type's characteristic, chose the key components, and completed EPS design.conducted the research to the commercial vehicle EPS's assist characteristic and control strategies, and selected the curve of assist characteristic, obtained under the different vehicle speed and the steering wheel torque input electric goal electric current. According to the designed EPS system, established vehicle model and EPS mathematical model, designed PID control and the fuzzy PID control strategy, as well as returns to under the control model PID controller and the damped control way. The union vehicle model and the EPS mathematical model, established the Simulink models, to automobile's boost characteristic, returned to the characteristic and the damping characteristic separately has carried on the simulation analysis. The paper contrasted under the EPS system boost control model to join conventional separately the PID control and fuzzy PID controls these two control method, the simulation result indicated: Used the fuzzy PID control strategy, vehicle's raw angular velocity reaction time to be shorter, the response to be quicker. Through to returns to the control characteristic simulation analysis, after EPS system joined the return control, the steering wheel can rapidly return to the middle position, avoided the steering wheel's vibration. Analyzed the damped control characteristic simulation, after joined the damped control, obviously reduced the vibration.