The Research On An Electro-Hydraulic Steering System For Wheeled Engineering Machinery

Wheeled engineering machinery has developed rapidly recently, because of its good mobility, adaptability to environment and so on. Along with the work efficiency's improvement, engineering machinery's automaticity is increasing rapidly. Correspondingly, the demands on control performance of machine system various parts are growing, for example, operate facilely, comfortably and so on. Electro-hydraulic steering system is one of core control technology of wheeled engineering machinery, which has an important role on improving heavy wheeled machinery's maneuverability and reducing driver's labor.Based on to many kinds of steering machine and control system's analysis, this paper presents the electro-hydraulic steering control system, which uses the proportional control. The system uses a proportional valve controlling the hydraulic cylinder, by installing sensors on the steering axis and the steering hydraulic cylinder, the control signal of the proportional valve can be determined by comparing the difference between the steering input signal and steering output signal, the proportional valve can control the cylinder's action, by this way, the steering system can implement the driver's operation on steering. Based on Ackerman's steering theory, this paper designs finer steering mechanism and achieves movement simulation using SolidWorks to keep the two steering wheels having a corresponding relation. This paper gives the mathematic model of the steering system, and the PID control simulation and experiment are carried out in. Through analyzing the results obtained from the investigation, it's concluded that the cylinder's action can track the input signals well under the commanding of low frequency and small stroke, the steering system can reach a satisfactory control performance. According to the relationship between the wheel steering angle and the cylinder displacement, the paper plots the practice steering characteristic curve, compared to the theory curve, one can find the steering system can satisfy the driver's purpose.