Research On Vehicle Dynamics And Control Based On Dynamic Contact Analysis Of Tire And 3D Road Surface

Nowadays,with the vigorous development of the transportation industry,the study of vehicle-road coupling dynamics is of great significance for active road safety control.In the vehicle-road system,the unevenness of the road surface is the basis for the realization of vehicle dynamics research.The establishment of an accurate threedimensional road surface is very important for the study of vehicle dynamics,and reasonable tire model is also an indispensable part of the vehicle-road system.In this article,an improved Lu Gre tire model with two-dimensional non-uniform pressure distribution is used,which is closer to the actual situation.Firstly,build an accurate three-dimensional pavement model with microtopography.Use the inverse Fourier transform method to construct two-dimensional road spectra of different levels and use the random midpoint displacement method to expand the two-dimensional road spectra to three-dimensional road spectra.Select a set of data in the longitudinal direction of the reconstructed road surface to analyze the power spectrum density of the road roughness.The results show that the threedimensional pavement spectrum constructed by the fractal theory method has high accuracy.Secondly,establish an improved Lu Gre tire model that can reflect the dynamic characteristics of the tire in real time.The pressure distribution method is nonuniform distribution and the tire model formula is derived.Analyze the tire longitudinal force,lateral force and return torque to verify the correctness of the tire model.During the actual driving of the vehicle,the length of the tire footprint is constantly changing.In the article,the tire static pressure test is used to obtain the change curve of grounding mark length and vertical load.Apply this law to the tire model to obtain the change law of tire force and vertical load.It laid the foundation for the establishment of the subsequent vehicle model.Thirdly,according to the static pressure test of the tire,the tire footprint shape is obtained and the contact model between the tire and the three-dimensional road surface is established.The contact model between the tire and the road surface is divided into a single-point contact condition model in which the tire is in contact with the two-dimensional road surface and a multi-point contact condition model in which the tire is in contact with the three-dimensional road surface.Under these two conditions,the dynamic response of a three-axle heavy-duty vehicle is analyzed.Finally,the vertical,lateral and longitudinal dynamics of the three-axle heavyduty vehicle model are controlled.In order to improve the ride comfort of the vehicle,a ceiling damping control algorithm and a fuzzy PID control algorithm based on semi-active suspension are constructed in the article.In order to improve vehicle handling and stability,a PID control algorithm based on the front wheel and a fuzzy PID control algorithm are constructed in the article.In order to improve the braking performance of the vehicle,the slip rate value is changed through the sliding film control algorithm in the article.The results show that the fuzzy PID control algorithm is better than the skyhook damping control algorithm in improving vehicle ride comfort.Fuzzy PID control algorithm is better than PID control algorithm in improving vehicle handling stability.The sliding mode control algorithm has obvious effects on the improvement of vehicle braking performance.