The Performance Analysis And Simulation Of The Electromagnetic Power Steering System

High effective energy saving, high comfort performance and high security are the goals of contemporary automobile technology. The first goal closely concerns with environment protecting, is also the popular topic around the world. The last two goals are the important subjects must be researched and solved in making automobile high performance. To make the steering system high performance is that the system can carry out multi-goals control according to the vehicle states and driver requirements to acquire the steering handiness, better road feeling, better anti-interfering performance and faster response.The power steering system has the advantages such as the steering sensitivity, handiness and absorbability of the impulse from the road. Now the power steering systems applied to operation are hydraulic power steering system (HPS), electric-hydraulic power steering system (EHPS) and electric power steering system (EPS). The electromagnetic power steering system illustrated in this paper is a new type power system. Compared with HPS, the electromagnetic power steering system has its special characters, such as the adjustable and manipulative features, to make the automobile under the ideal control and it has the simpler structure than EPS.This paper will illustrate the structure and work principle of the electromagnetic power steering system, and analyze the system's technology requirement and force states. An electromagnetic power steering kinematics model is built combined with the sensor and power equipment's kinematics characteristic, then according to bond graph theory the bond graph model and diamond model of the electromagnetic power steering system are built based on the kinematics model. They could lead to the system's transfer function, which is combined with automobile's two freedom degree model, finally leads to the system's model in condition with step input of steering wheel.This paper makes use of PID control, Fuzzy- PID control based on single parameter these two control strategies to simulate the system's model. Compared with common vehicle, the results of simulation show that the vehicle equipped with the electromagnetic power steering system has better yaw velocity frequency response characteristic under condition with step input of steering wheel, so it has more betterhandling stability; Compared with PID control strategy, the results show that the Fuzzy-PID control strategy has the advantages, such as response fast, stabilize itself quickly and less over-altitude.