| With the progress of automotive-related technology, automobile power steering system has gone through several stages of development, including hydraulic power steering system, electric hydraulic power steering system and electric power steering system. Electric power steering system with the advantages of compact structure, low energy consumption and easy assembly has become a future development direction of automobile power steering system.Based on the basic control strategy on the EPS system, compensation control system is designed in this dissertation.Firstly, this dissertation describes the structure, classification and modeling process of EPS system.The EPS modeling study is divided into various modules.lt studies the power characteristics, booster motors, PID control, return-to-centure in the dissertation.lt also builds model in simulink, and it has laid a foundation for compensation control strategy and co-simulation for EPS system.Secondly, it analyzes the generation and impacta of inertia and friction, and join compensation control strategy.This dissertation designs inertia compensation control and friction damping compensation control. Catia is used to measure the inertia of system. EPS test table is used to measure the friction of system.Thirdly, it uses Carsim to build car model.And set parameter of the body, transmission, brake systems, suspension systems, tires and other parts.Fourthly,it builds the co-simulation platform of EPS and car based on Simulink and Carsim and does simulation tes.This dissertation verify correctness of compensation control through steering agility simulation,step input simulation,return-to-centure tests.Finally, the real vehicle test is implemented in accordance with the relevant national standards to verify the effectiveness of the EPS compensation control. The real vehicle test results show that the EPS controller can improve the steering portability and the return-to-center performance of the test vehicle. |
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