Research And Design Of Automotive Electric Power Steering Control System

Automotive Electric Power Steering System (EPS) is a new type of power steering systems.With the development of automobile electronic technology, electronic technology has beenapplied in all aspects of the car. EPS is the most widely used in the small car. In the EPS system,the assist motor is a power source of the assist system, and the electronic control unit controls thesize of the assist system. Characteristics of the EPS system are booster size adjustable, good roadfeel, environmental protection and energy saving features. Therefore, the EPS system design is avery important part of automotive electronic control system and the focus countries inautomotive electronic technology research.This thesis on the basis of in-depth study of the EPS system, based on the works as well asthe characteristics of the EPS, the key components of the EPS system the selection of the modelto provide a basis for the development of the system as a whole.And assist features and control strategies for the EPS system, designed a fuzzy controller.Get different steering wheel input torque and speed the assist characteristic curve, by Matlabsoftware simulation results show that the power control strategy of fuzzy control in the EPSsystem steering the process of control is realistic. Followed by the classic PID control contrast,the design of adaptive fuzzy PID controller, simulation results can be obtained using fuzzycontrol algorithm to determine the EPS boost feature is effective, has a high response rate andgood tracking.Finally, the development of the ECU hardware design based on MC9S12DP256MCU setelectric power steering system. Description of the permanent magnet brushless DC motor drivingcircuit, relay driving control circuit, electromagnetic clutch driving control circuit. According tothe functional requirements of the electric power steering system (EPS) system, the compositionof the ECU software design and work flow chart.