Design And Dynamic Analysis Of Multi Axle Steering System For Commercial Vehicle

Multi-axle steering technology can greatly improve the maneuverability of the vehicle and the handling stability.In this paper,a heavy four-axle truck is studied.The first axle of the vehicle is equipped with hydraulic power steering system,and another three axles is equipped with electric-hydraulic steering system,which enables the truck to be steered with multi-axle.Main research contents are given as follows:(1)The working principle of multi axle steering vehicle is analyzed,and the optimization design of steering mechanism is done.The linear 2DOF mathematical model of four axle vehicle is established,and based on the four wheel steering classical control method,the multi axle steering method of the four axle vehicle is designed,and the response characteristics of the vehicle are analyzed.(2)The dynamic model of the vehicle is established in TruckSim.Simulation results between the 2DOF model and TruckSim model was showed the accuracy of the model.Then,a multi-axle steering control algorithm based on proportional feed-forward and optimal feedback is proposed.The simulation is carried out at low speed and high speed,and the results show that under the same conditions,relative to the traditional double front axle steering vehicle,turning radius can be reduced 44%,tire wear and the stability of vehicle at high speed can be effectively improved.(3)Center-position cylinder was adopted in the electric-hydraulic steering system for multi-axle steering,the working principle of the hydraulic system is designed,and the key parameters involved in the system are calculated.The mathematical model of hydraulic system is established and its stability is analyzed.At last,the electro-hydraulic steering system model was developed in AMESim,and parameterized simulations were conducted,which can draw a conclusion that the electric-hydraulic system was reliable.(4)Based on "TruckSim-Simulink-AMESim" joint simulation environment,the comparative analysis was carried out and the results show that the electro hydraulic steering system has no influence on the dynamic characteristics of the vehicle.Then some factors which affect the vehicle handling stability are analyzed,provides theoretical guidance and practical reference for subsequent design of robust control algorithm.