Research On Steering Test System For Heavy Duty Vehicles And Its Static Steering Resisting Moment

Heavy vehicles are widely used in the construction of military infrastructure and heavy industry areas because of its strong dynamic performance and high load carrying capacity.The high performance steering system can enhance significantly the heavy vehicle low speed maneuvering flexibility and high speed handing and stability.It has become the measure of modern large-scale weight vehicle and one of the key frontier technologies and equipment development carried horizontally carrier vehicle.At present,there are some matching design problems in the between the hydraulic system,the steering system and the steering resistance moment in the process of steering,which often results in the damage of the steering linkage and the wear of the tire.The fundamental reason is the influence of tire turning resistance moment.Therefore,this paper proposes a mathematical model based on the tire mark steering friction mechanism,which can describe the moment resistance of the tire in situ steering.First of all,The mechanism of friction between tire and road surface is analyzed,and the influence factors of tire steering resistance moment are determined.based on the friction mechanism of tire mark steering,a mathematical model is presented to accurately describe the maximum resistance moment of tire in situ steering;In this paper,research the effects of different load distribution form to steering torque on tires mark region,and-then obtain the resistance moment of tire trace load distribution model;Compared empirical formula of steering torque resistance with the traditional steering resistance moment of tire,and combine with the tire magic formula,a mathematical model is established,which can reflect the dynamic relationship between steering resistance torque and wheel angle.Secondly,based on heavy vehicle Steering mechanism of Single axle,a test bench is designed to test the steering performance of heavy vehicles.According to the structure characteristics of the main frame,the influence of the single and double loading modes on the structure of the main frame is analyzed;According to the bench structure characteristics,analysis of the key design parameters(guide column number,guide column diameter,Thickness of bearing plate and so on)effect on the test bench for performance oriented structure;according to the analysis results,selecting the optimal structure parameters,research and development of test bench prototype.Then,based on the mechanical structure of the new steering pertormance test stand,the electro-hydraulic servo steering system and electro-hydraulic servo loading system are designed.Analysis of the effect of tire load,loading frequency,proportional gain,hydraulic cylinder leakage,proportional valve dead zone and hysteresis and other factors on the performance of the system;according to the results of the analysis,completed the selection of hydraulic components,to build test system.Finally,according to the steering test system,the resistance moment of the tire in situ steering is studied.Based on the test tire marks,analysis of the influence of load on the tire mark size;Based on the steering resistance torque test,study of tire load,wheel steering angle and speed on the influence of the steering resistance moment;The experimental data are analyzed to verify the accuracy of the mathematical model.The innovation of this paper is that based on the friction mechanism of tire steering,a new method is presented to describe the resistance of tire in situ,and the accuracy is verified by experiments.Based on the tire blot test,the effect of load on the tire imprint size was studied,and the mathematical model of load and imprinting is established;The experimental study on the resistance of tire steering resistance was carried out,and the effects of tire load,wheel angle and steering speed on the torque were obtained;The experimental data are analyzed to verify the accuracy of the steering resistance moment model.