Electro-hydraulic power steering system (Electro-Hydraulic Power Steering System referred to EHPS) set of hydraulic power steering and electric power steering in one of the advantages, EHPS system uses a DC motor-driven hydraulic power steering pump, power steering with engine speed even if not related, according to need to provide help of steering, but also play a hydraulic drive system for the energy density advantage, due to the presence of the hydraulic system to improve the smooth steering feeling the impact attenuation of the road and improve driving comfort and safety. In this paper, based on previous studies, further study of the EHPS ideal power system characteristic curve, through a real-passenger vehicle tests, the car's power curve. For its strong non-linear power curve, based on neural network has good ability to approximate any complex non-linear, using the BP neural network technology to fit the power curve obtained speed, steering wheel angular velocity and motor speed of nonlinear relationship between the curves, the basis for system modeling. AMESim and Simulink software combines the features and advantages of their application to build EHPS system simulation model, a joint simulation of a simulation analysis EHPS system.Original selection of Freescale microcontrollers - MC9S08AW32 the EHPS system hardware design, each module of the controller design of specific hardware circuits. In the PCB design process considered issues relating to electromagnetic compatibility.Supporting the development of software using the latest Code Warrior 6.2, according to the main flow EHPS system software programming and the use of a digital PID control theory to achieve motor control, the last of the brushless DC motor for PWM modulation.In the final stage of the controller of the experimental bench experimental results show that the controller performed well, but in some areas still need improvement.
Key words: electric hydraulic power steering, neural networks, co-simulation, microcontroller, digital PID
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