| Along with the development of the highway network and the automobile industry,the road transportation has improved rapidly in recent years.Due to its strong bearing capacity,high quality utilization coefficient,large transportation capacity and low transportation cost,automobile and train transportation has been widely applied.The trailer,driven by traction connecting device,follows tractor steering passively,which brings a series of hidden danger.Due to the steering mechanism,folding or wagging(trailer swing)phenomenon occurs when full trailer train runs in the small-radius curve or breaking.Therefore,in order to improve the transportation efficiency of the train,it is imperative to improve its safety performance.The full trailer train can be divided into three parts: the tractor,the trailer and the traction connecting device.This paper,based on a double-pole hydraulic full trailer train,puts forward active steering control method,by which the function of the connection device has changed.The active steering control method will better control the trailer steering.Because of the use of the method,trailer can follow tractor steering actively,and the coupling between the trailer and tractor is reduced.An active-steering control system of the double-pole hydraulic full trailer train is established in this paper,in which the ECU judges the running state of the tractor according to the movement parameters of it collected by sensors,and sends control instruction to the trailer controller through the communication network.Then,the trailer controller changes the parameters of double-pole hydraulic system,by which the full trailer train will get different traction in magnitude and direction and achieve the active steering.Based on the analysis of the Ackerman steering principle,the proportional control relationship between the tractor speed and the length of the hydraulic pole has been deduced and the open-loop simulation has been carried out.The transfer function is obtained by establishing mathematical model for each device of elector-hydraulic control parts,and the simulation analysis have been carried out to get the dynamic performance of it.A mathematical model of the vehicle is established based on the yaw motion andlateral motion of the hydraulic double-pole mounted trailer train,and the open-loop simulation of it is performedThe active steering control system containing all the mathematical models of each part,is simulated in MATLAB/Simulink.Through it,the stable output response curve of the system and the track map of the full trailer train,under the step input,can be obtained.The results show that the active steering control system is stable and can improve the steering stability.The PID control algorithm and genetic algorithm are used to optimize the active steering system.The comparison between the two algorithms shows that both of them can improve the rapidity of the system,but the stability of the system response under the optimization of the genetic algorithm is better than that of the PID control algorithm.The trajectory of the full trailer train under the action of the genetic algorithm is improved.The joint simulation of MATLAB and ADAMS is carried out on the full trailer train by establishing the virtual prototype model and MATLAB ports in ADAMS.Through the simulation,the trajectory map of the vehicle which drives on a S-curve rode under the action of the active steering control system,is obtained.The joint simulation result shows the good following performance of the full trailer train.In order to conduct confirmatory experiments,the physical model of double-pole hydraulic car train is made,the hardware circuit is designed,and the control program is programmed.Through the running of the small-scale vehicle model,its motion state and the effect of active steering control can be observed more directly.The simulation results verify the stability and feasibility of the active steering control system. |
PDF Full Text Request