Research On Parameter Optimization And Steady Rotation Characteristic Of Center Axle Trailer Train

With the development of e-commerce and transportation logistics industries,people are increasingly demanding transportation speeds and single-passenger cargo transportation.Most of goods are transported by road transport vehicles.With the enactment of the newly revised GB1589-2016,the middle axle trailer train is about to become the mainstream of highway transportation in the future due to its high efficiency and capacity.Center axle trailer train is used for transporting small and medium-sized cargo,which speed is high when driving on the highway.Because of its special structure and long size,it is inclined to produce risk when turning.Therefore,it is necessary to research and optimize the steady rotation characteristics of center axle trailer train.It will improve its safety and stability.First of all,this paper simplifies the structure of the center axle trailer train and establishes a 10 degree-of-freedom movement equation,including longitudinal,lateral,yaw,roll,and pitch of the tractor and middle axle trailer respectively.According to its equations,the mathematical formula of the yaw rate gain and stability factor of the center axle trailer train in steady state is obtained.In the TruckSim,a vehicle model of center axle trailer train is built.The steady rotation test was carried out on the real center axle trailer train,and the steady rotation simulation with the same conditions was also carried out in TruckSim.The correctness of the simulation model was verified by comparing the lateral acceleration,yaw rate,roll angle,trajectory in the test and simulation,and the correctness of the steady response mathematical model was verified by the simulation model.Steady rotation performance of the center axle trailer train is analyzed by comparing parameters,such as the stability factor,the difference between the front and rear shaft sideslip angle and the turning radius ratio.In order to deeply evaluate the steady-state rotation characteristics of the center axle trailer train,objective and subjective evaluation method are used to analyze and evaluate the steady rotation performance.In order to further analyze and save time,scoring software for evaluating steady rotation test was designed through graphical user interface,which based on the GUI module in MATLAB.Finally,the parameters of the center axle trailer train are optimized for reaching higher scores in the steady rotation test.The influence of seven structural parameters,such as the position of vehicle centroid and the traction pin(ring),on the steady rotation performance of the truck train is analyzed.A quadratic response surface model was constructed to evaluate the scores of other five parameters except the centroid height.The genetic algorithm is selected for optimization.It is proposed that the steady rotation characteristics of the vehicle can be improved.The results of the study indicate that the optimized steady rotation performance of the center axle trailer train has been greatly improved,which effectively reducing the yaw rate,lateral acceleration,and roll angle at high speeds.It means that the stability factor and comprehensive evaluation scores are improved significantly.