Study On Steering Characteristics And Control Methods Of Three-axle Heavy Vehicle

Heavy duty vehicles are an important part of the segment market of automobile products and have a pivotal position in the national economy and national defense construction.Compared with the passenger car,it has a larger weight and the size of the profile,usually install multiple axles,and the shaft layout in various forms,need multi-axle involved in steering.Therefore,by studying the steering characteristics of heavy vehicle to improve its mobility and stability in the steering,reduce the frequency of tire replacement has a very real significance.In this paper,a three-axle heavy duty truck is taken as the research object.According to the basic steering principle,the geometrical relationship of the wheel angle under different steering modes is deduced.The mathematical model of rocker-link mechanism of the steering system is deduced in the dual-front axle steering.According to the ideal angle relationship,the structural parameters of the steering geometry is optimized,and the feasible optimization results are obtained.By analyzing the dynamic characteristics of three-axle heavy duty vehicle in steering,the mathematical model of 3-DOF angle input based on the vehicle is built.Taking into account the tyre cornering characteristics and vehicle body's roll movement these two factors that can not be ignored,multiple simulation models about tire and vehicle are established in Simulink simulation environment.The influence of steering mode,speed and axle layout on the steering characteristics of three-axle vehicle is analyzed by simulation,and the simulation results are analyzed and evaluated.Based on the 2-DOF model,with center of gravity zeroth yaw angle as the control target,and the rear wheel angle is the control object,and the control equations of different rear wheel angles are deduced.The influence of different control methods on the steady response parameters of the vehicle is studied.Then,based on Simulink this simulation tool,the angle input model under different control methods is established.The influence of the control method of the rear wheel angle on the steering characteristics of the vehicle is compared and analyzed,while the effectiveness of the control method is verified.