Study On Dynamic Wheel Load Of Heavy-duty Tractor Under Rough Road Surface

With the rapid development of the transport and logistics industry,multi-axle heavy-duty tractor-trailer has become the major form for our road transport and the long-distance transport,resulting in the stage of high-speed heavy load traffic.Heavy-duty vehicle is an important cause of early pavement damage,because its dynamic load is far greater than other vehicles.High efficiency,safety,energy saving,comfort and road friendliness has become the main trend of heavy-duty vehicle.Compared with imported brands,the attention for ride comfort and wheel dynamic load that domestic manufacturers paid is not yet enough,and there is in urgent need to enhance the competitiveness of products.The ride comfort and wheel dynamic load are two important performance indexes in the process of the vehicle comfort and road friendliness evaluation.In this paper,a certain type of domestic heavy tractor-trailer is the research object.The powertrain model,front and rear suspension model,the cab model,the road and tire model are built by using the tractor frame model,the semi-trailer model and test data for each component provided by enterprises,and eventually the whole vehicle multi-body model is built in the multi-body dynamics software ADAMS/View.A frequency filtering calibration method of vibration rig on the input displacement signal is proposed.The error between the transfer characteristics of vibration system of vibration rig and the target transfer characteristics is analyzed,then based on Butterworth low-pass filter,the calibration filtering function is generated.The results verified by vehicle test data show that the accuracy of vertical acceleration signals simulated of axle ends is greatly increased after the vehicle vibration rigs are calibrated,which proves feasibility of the method that can ensure benchmarking accuracy of vehicle model making full use of the measured vertical vibration acceleration signals of axle ends.Then,verify the correctness of tractor-trailer model by contrast the test results.The wheel dynamic load and ride comfort with typical speed and full load conditions under rough road excitation is in-depth study.With the method of step-by-step optimization,the vehicle parameters are optimized.First of all,to optimize the ride comfort by choosing driver seat rail location vertical vibration acceleration RMS value of the tractor as the optimization goal,choosing the stiffness and damping of chassis and cab suspension system as a design factor,the limit of suspension travel as a constraint function.Then to optimize the wheel dynamic load based on the vehicle ride comfort by choosing the limit of suspension travel and optimized driver seat rail location vertical vibration acceleration RMS value as constraint functions,the maximum sum of value combined with tractor wheel dynamic load as the optimization goal.Compared the results of optimized with initial model,the tractor-trailer has an obvious improvement in ride comfort and road friendliness.