The Research On Electric Power Steering System With Active Return-to-Center Function

Electric Power Steering(EPS)System is porpular among more and more customs,because of its fuel economy and portability.But the application of EPS brought poor outcomes on the on-center performance.So an active return-to-center function has to be added.An angle sensor was necessary to test the center position accurately.In this paper a new integrity sensor was developed for low cost design.The main content of this paper as follows:1)The development status of EPS system and the key part of the system was analyzed,and the reason of this task was introduced.2)The structure of the component of EPS system was analyzed,base on the 3D modoule.A matching analysis was made.3)In this task the author analyzed the strength of the component of EPS system,with the software of ANSYS,especially the static contruct analysis module,including the steering shaft,worm gear,outer shell.4)In this task the author developed a hall type angle and torque integrity sensor,analyzed the angle module and torque module respectively.And finish the manufacture of the sample.5)The reason that the steering wheel can not returning to center after the adition of EPS system was analyzed.An active return-to-center control was introduced,including the judgement of return working condition,and control strategy of PID,fuzzy PID controller.6)At the end of the thesis,the author introduced the test condition of the sensor and EPS system.A new measuring algorithm was designed to reduce deviation.Debugging of the EPS system under the whole vehicle condition brought a good performance of handfeel,and then test in the labroom.