Research On Vertical-lateral-longitudinal Coupling Dynamics And Comprehensive Performance Coordinated Control Of Heavy Vehicles

Heavy-duty vehicles have the characteristics of high transportation efficiency and low transportation costs,and have become the main ways of road transportation.It is necessary to ensure that the transportation process is safe and accident-free,but also to ensure that it is fast and does not damage the goods.Therefore,it is necessary to improve the ride comfort,handling stability and braking performance of heavy vehicles to meet the needs of the transportation industry for efficiency and safety.The vertical,lateral and longitudinal motions of the automobile interact,coordinate and correlate with each other.However,the single-direction performance optimization is difficult to meet the needs of complex working conditions.Therefore,the vertical-laterallongitudinal coupling dynamics modeling and control of of the entire vehicle are studied.Two-dimensional three-axle heavy-duty vehicle dynamics model is studied.A two-dimensional three-axle heavy-duty vehicle vertical model and a laterallongitudinal model are established respectively,and the two models are coupled through the "magic formula" tire model to propose a two-dimensional three-axle vertical-lateral-longitudinal coupling model.Through simulation analysis and comparison,the interaction and movement characteristics of the vertical,lateral and longitudinal movement of the two-dimensional vertical-lateral-longitudinal model are summarized.At the same time,it demonstrates the necessity of establishing the threedimensional coupling model.A three-dimensional three-axle heavy-duty vehicle vertical model and a laterallongitudinal model are established,and a three-dimensional three-axle vertical-laterallongitudinal coupling dynamic model with 18 degrees of freedom is proposed based on the "magic formula" tire model and the relationship between all directional motion and roll motion.The correctness of the three-dimensional vertical model is verified by comparison of simulation and experiment,and the interrelation and influence path of the vertical,lateral and longitudinal motion of the three-dimensional model are summarized,which lays a foundation for the final optimization research on ride comfort,handling stability and braking performance.The semi-active suspension fuzzy sliding mode controller based on the threedimensional three-axle heavy-duty vehicle dynamics model,the active front wheel steering fuzzy PID controller and the optimal slip ratio sliding mode controller are respectively proposed.Research indicates that the three controllers can effectively improve the ride comfort,handling stability and braking performance of the threedimensional three-axle heavy-duty vehicle dynamics model;based on the vertical-sidelongitudinal coupling vehicle model,a coordinated control scheme of three controllers is proposed.The simulation shows that the proposed the cooperative control strategy can simultaneously improve the ride comfort,handling stability and braking performance of the three-dimensional three-axle heavy-duty vehicle.