Research On Steering Stability And Instability Of Multi-axis Heavy Vehicles

With the quickening pace of society, the speed of modern vehicles is more and more fast, which brings traffic safety hazards greatly, how to ensure the vehicle handling and stability in case of high speed has become an important issue of the development of modern vehicles, particularly heavy vehicles. The development of multi.axis cause the vehicle all.terrain crane leap.type development, all.terrain crane with high technical content, developes difficultly and so on, it reflects the overall strength about the level of modernization of national engineering equipment manufacturing industry. However, compared to the technology, China start later all.terrain crane than foreign countries, there is still a gap compared to International standards on Multi.Wheel Steering,we should explore and study about this further.In this paper,use the basic theory of multi.body system dynamics, take XCMG xuzhou Heavy Machinery Co.,Ltd production of QAY125 all terrain crane as the prototype, With ADAMS/View tool,build the virtual prototype of all terrain crane with five axles. According to the government vehicle stability test methods, combining the virtual prototype model and the MATLAB/Simulink control procedures,and then Co.simulation.According to the basic principles of multi.axis steering,use the Nonlinear tire model of the Professor of Shanghai Jiaotong University,Qu Qiuzhen,build the handling dynamics model with the nonlinear tires vehicle, and calculate the n.order approximate solution of yaw rate, side slip angle when the vehicle is steady state and dynamics. And then theoretical simulation the vehicle when it is in the simulation of angle step input and steady rotation use MATLAB/Simulink tool. The results show that, steering characteristics of Multi.axis Steering Vehicle are related with centroid position of the body, the tire cornering stiffness, axis distribution and it's mass and so on.Simulation and analysis of the results of vehicle is closer to the actual situation in life use nonlinear tire model.And then the paper introduce the theory of ADAMS and it's methoreds of building model. Based on this, build the model of body, axles, steering linkage, steering cylinders, tires and allt the steering system of QAY125 All Terrain Crane and the others. Based on the real vehicle, proposed program of vehicle steering control, Through the establishment of the ideal model and the mathematical model of the ctual vehicle model, caculated and got the Control theory and control strat..egy of the paper.Introduce the application of MATLAB/Simulink briefly, build the co.simula tion model of ADAMS virtual prototype model and the Simulink control model, analysis the Vehicle yaw rate, sideslip angle and the other Parameters which can re..sponse the vehicle performance in the three conditions,thronugh analysing the res..ults, evaluated some specific performance of vehicle.In the final, analyze the factors which could lead to vehicle instability and the response of vehicle vehicle instability, deduce the mandate of vehicle driving stability with nonlinear tires.