Research And Realization Of BY-Wire Hydraulic Steering System Based On Fuzzy Control

This paper designed a by-wire hydraulic steering system, with rational space layout and simple structure. The system can replace the complex mechanical transmission mechanism of the traditional steering system, transmit of electrical signals, instead of hydraulic kinetic energy transfer in the hydraulic steering system, can also achieve closed-loop control, then made better regulation and control of vehicle steering stability properties, which is also a direction of vehicle electronic control. The design of the system in this paper is divided into three sections: mechanical, hydraulic, electrical.Firstly, this paper described the basic physical characteristics of the vehicle steering system, analyzed its steering mechanical transmission. According to the vehicle’s steering characteristics, this paper analyzed the transmission characteristics of the transmission mechanism, and set up mathematical model based on the relevant steering parameters, gave the control logic to solve sliding phenomena during steering, increased the anti-slip function for the whole hydraulic steering system.Secondly, this paper analyzed and compared several popular current hydraulic electronic control schemes, proposed a simple and practical electro-hydraulic scheme, the hydraulic schematic diagram was also given. By the simulation of the hydraulic system in the AMEsim software, the paper obtained the curve parameters from the hydraulic simulation, verifying the correctness of the model.Thirdly, the paper completed the electronic control parts of by-wire steering system, including the circuit design and software design of the control system based on TMS320F2812. The circuit design implemented the signal conditioning of sensors (steering wheel angle sensor, cylinder displacement sensor)and actuators (electro-hydraulic proportional valve PWM), matching with the power distribution and the interface module of power supply of the TMS320F2812. The design of software used A/D acquisition and PWM signal transmitter modules in TMS320F2812, achieved the functions of the sensor signal acquisition and PWM signal transmitter. The fuzzy control algorithm used in the main program for signal processing, achieved closed-loop control of the system.Finally, experimental platform of the hydraulic system was set up, and simulation experiments of the software and hardware parts of electric control were completed. This paper initially realized the basic functions of the hydraulic circuit of the by-wire steering, obtained analog signal data and graphics, proving the correctness of the design of the by-wire hydraulic system.