| The driving environment of commercial vehicles is mainly closed roads such as expressways and provincial roads,which shows obvious advantages in the promotion of intelligent driving compared to passenger vehicles.Electro-hydraulic coupled steering system is the executive mechanism of lateral control of commercial vehicles in path tracking.There are some problems such as parameter time-varying,response lag and model uncertainty.In addition,compared with passenger vehicles,commercial vehicles are prone to roll instability during steering.Active roll control can improve roll stability.However,the lateral dynamics and roll dynamics of vehicles are coupled through the product of lateral-roll inertia.Vehicle roll dynamics is affected by the angle input of the lateral control system,and the lateral dynamics is also affected by the control input of the anti-roll system.Therefore,active anti-roll control will affect the accuracy of path tracking,and lateral control will affect the effect of anti-roll control.Aiming at the above problems in the lateral control of commercial vehicle path tracking based on Electro-hydraulic coupled steering system,this paper first establishes the joint simulation model of commercial vehicle-electro-hydraulic coupling steering system,and simplifies the two-degree-of-freedom linear control model from steering wheel to wheel angle.According to the dynamic requirement of the lateral control of the upper layer of the vehicle for the response of the steering system,a system control model with ideal response characteristics is designed.Aiming at the time-varying parameters and uncertain model of electro-hydraulic coupling steering system,the angle control strategy of electro-hydraulic coupling steering system is designed,and the angle controller of steering system is designed based on Narendra model reference adaptive theory.Secondly,based on linear quadratic optimal control theory and multi-point preview driver model,a lateral controller for path tracking is designed.In order to improve the roll stability of commercial vehicles in the process of path tracking,an active roll-resistant controller is designed based on linear quadratic optimal control theory.Furthermore,considering the control interaction between the lateral control of path tracking and anti-roll control,and weakening the mutual coupling between them,a lateral-anti-roll cooperative control strategy is designed based on cooperative Pareto optimal equilibrium theory.Finally,the above control strategies are simulated and validated.Based on hardware in the loop test(HIL),the steering system angle control strategy and the path tracking lateral controller are validated. |
