Research On Adaptive Fuzzy Sliding Mode Control Of E-ECHPS System Consideration To Maneuverability And Energy Saving

Heavy-duty vehicles commonly use hydraulic power steering system(HPS)which assist characteristic is single. Since the provided assist torque of HPS can not change with speed varying which is hard to meet the requirements of portable and sensitive. Otherwise, the steering pump is always working at a high speed when the vehicle is running, it means that a lot of useless consumption is produced in the hydraulic system. Based on the existing research of studying team combined with the characteristics of electromagnetic slipping clutch(ESC), the control technology of the electronically controlled hydraulic steering system based on ESC(E-ECHPS) is presented and E-ECHPS can provide an appropriate assist torque under different conditions and reduce the energy consumption according to control the speed difference of ESC. The primary contents of this paper are as follows:On the basis of analyzing domestic and abroad research on the current situation of steering technology and combining with the characteristics of ESC, a design scheme of the new type electronically controlled hydraulic power steering system which implements the speed regulation of pump by ESC is proposed. In detail to introduce the structure characteristics and working principle of E-ECHPS, the mathematical models of various subsystem of E-ECHPS 、 ESC、 three degrees of freedom vehicle and tires are established, and the energy consumption of E-ECHPS is analyzed.Aiming at the existing problem that portable and sensitive of traditional HPS when vehicle steering, the design requirement of the assist characteristic is determined preliminary. According to the related theory knowledge, and based on the formation mechanism of steering resistance moment, the mathematical model of steering resistance moment is built. By comparing with the energy consumption of HPS, the energy saving mechanism of E-ECHPS is described. Referring to the design method of ECHPS assist characteristic curve and use the method combined with experiment and simulation, a parabolic type assist characteristic curve for E-ECHPS is designed.Considered the parameter uncertainty and external interference when E-ECHPS is working and combined with the related control strategy, an adaptive fuzzy sliding mode control(AFSMC) strategy is developed. Compared with PID control, the simulation results show that AFSMC not only can guarantee the system to track theideal signal preferably, but also has low overshoot volume 、fast response and well robustness anti external interference. Finally, the test bench of E-ECHPS is designed,and the simulation test is conducted. The experiment results prove that the assist characteristic of E-ECHPS is variable, and the energy saving efficiency is better than HPS.Consequently, the assist characteristic curve and control method of E-ECHPS researched in this paper solve the existing problems of heavy-duty vehicle steering system effectively, it helps to improve the maneuver stability of heavy-duty vehicles and reduce the energy consumption of the steering system. It has the reference significance for further research and application of E-ECHPS.