Analysis And Design Of An Electric Power Steering System

Because of the advantages such as the steering sensitivity, handiness, and absorbability of the impulse from the road the power steering system is widely used since 1950's. Now the Hydraulic Powering Steering (HPS) is still mainly used in the automobile drived by internal-combustion engine. But it also needs the continuing consume of fuel to keep pump running, so it reduces the economy of fuel .And its complex hydraulic system pollutes the environment, makes the repairing difficult and the features couldn't be adjusted conveniently. Compared with HPS, the Electric Powering Steering system (EPS) has its special characters, such as the adjustable features, environment-friendly, energy saving and convenient maintenance, so it is developed quickly since some world famous automotive companies begin to research the EPS powering steering in 1980's.EPS is a new electric technology for automotive. This paper firstly summarizes the status of EPS and introduces the principle, structure and trails of EPS. Some data about the torque sensors is given and some information about its electric control unit (ECU) is discussed. Because the importance of the stability of the automotive handling for the security and comfort characters of the automobile so the control strategy of EPS should be firstly concerned. After kinematical analyses of the automotive steering system the torque and angel dynamic models are built and kinematical character of the automobile steer can be learned through the simulation via the MATLAB/SIMULINK software. Then an EPS model is built with the sensor and controller's kinematics analysis . PD control strategy and the factors influencing the driver's road feeling are discussed. Here a new control strategy fuzzy control is brought out .The simulation results show that it can response and stabilize itself more quickly with less over-altitude than PD control strategy. So if data about the automotive steering system can be got through the experiments, the useful effective strategy of EPS may be obtained under the guide of fuzzy theory.