Structural Parameters Optimization Of EPS Based On Brush Motor

With more and more applications of Mechatronics and CAD/CAE technologies intothe automotive industry, the study on electric power steering system (EPS) has becomeone of the most popular issues in automobile research field. The cars equipped withEPS can both steer lightly at low speed and get enough road sensitivity at high speed.Meanwhile, it contributes to energy saving, environmental protection, passive safetyetc. Therefore, electric power steering system has a broad prospects for development.In this paper, the development and application status of EPS and ModernOptimization Design used on automobile are analyzed. According to the compositionand working principle of EPS, a C-type EPS model is established by CATIA. Thestructure of mechanical energy absorption systems is researched and set up in order tomeet the requirements of automobile passive safety.In terms of the requirements of matching EPS with the whole vehicle, theparameters of brush assisted motor and reducer are selected. Based on the workingdemands, a pair of worm and gear of reducer is designed, and the design parametersare optimized to make the center distance minimum by the function fmincon inMATLAB optimization tool box. Then analyze the stress of worm and gear meshing.Take the influence of stiffness and flexibility on EPS into consideration, design thestructural parameters of the torsion bar in the torque sensor. Then optimize theparameters to make the maximum stress on the surface of the torsion bar minimum byANSYS Workbench. Besides, fatigue analysis carries out on the torsion bar.This paper uses modern design and analysis software to design and optimize someimportant components of EPS. And provide some methods to make the design morequickly and conveniently in the future.