Automobile electric hydraulic power steering system control method

Abstract

The invention discloses an automobile electric hydraulic power steering system control method. A controller collects a vehicle speed signal and a steering wheel angle speed signal, and a motor target speed value is determined by an assistance characteristic curve determined by vehicle parameters and EHPS system parameters according to a steering wheel torque preferred by a driver and a variation curve of lateral acceleration and travel speed. By virtue of a double closed loop control system of outer ring rotational speed control and inner ring current control, the revolving speed of an oil pump-driven motor is subjected to self-adaptive fuzzy PID control, the target speed of an oil pump-driving motor is controlled, and the output flow of a hydraulic oil pump is indirectly controlled, so the relaxation and convenience of directional steering and steering hand feeling are satisfied, the purpose of energy consumption reduction is also achieved, and the manipulation and safety of automobile driving are effectively improved.

Description

technical field [0001] The invention relates to an automobile hydraulic power assist system, in particular to a control method for an automobile electric hydraulic power steering system. Background technique [0002] Most modern cars are equipped with power steering systems to meet people's ever-increasing requirements for car handling comfort and portability. The traditional hydraulic power steering system is mainly composed of hydraulic pump, steering wheel input shaft, steering control valve, oil storage tank, power cylinder and so on. The engine is used as the power source to drive the hydraulic pump to build up a certain pressure, and then the steering control valve is used to adjust the pressure and flow of the oil flowing to the booster cylinder, and the steering wheel is driven to turn to realize the steering of the vehicle. During the steering process of the vehicle, the steering action is still completed by the driver, and the oil pressure of the power steering sy...

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Problems solved by technology

200810019629.5 [China] proposed an electro-hydraulic steering system for buses and a steering control method in which the motor and the steering oil pump are separated. The controller reads the vehicle speed signal, the steering wheel speed signal, the engine speed signal and the motor current signal. According to the driving conditions of the vehicle (urban driving conditions, rural driving conditions, rough road driving conditions, expressway driving conditions, parking conditions and parking conditions) and different steering conditions, the oil pump is The output oil flow is controlled in two stages according to the change of the steering wheel speed, but it is difficult to accurately judge the driving conditions of the vehicle in this method

[0004] The above-mentioned patents start from the perspective of improving the lightness of low-speed steering and high-speed feel, and control the motor in stages, which is difficult to meet the current people's requirements for energy saving, steering stability and driving safety.

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