Study On Stability Control Strategy Of Heavy Vehicles Based On Phase Space Three-Dimensional Dynamic Stability Domain

The development of autonomous driving technology has brought new opportunities to the automotive industry and related technologies.Various advanced driving assistance systems and even autonomous driving systems have been equipped in a large number of automotive products.As the insurance for autonomous driving systems,stability control technology plays an important role in ensuring the safety of vehicles and drivers.Robust control theory emerged in the 1980s and matured with the publication of Doyle’s DGKF paper in 1998.It has now become an important technical means familiar to engineering technicians.Considering this,the thesis takes the vehicle handling stability as the research object,robust H_∞control and extensible control are used as control methods,the front wheel steering angle and lateral yaw moment were trated as control objects,aiming to improve the stability limit of the vehicle and ensure the safety of the vehicle and driver.Heavy commercial vehicles have characteristics such as large moments of inertia and slow control response.This thesis establishes a four-degree-of-freedom longitudinal-lateral-roll-yaw dynamic model for heavy commercial vehicles.The accuracy of the model is verified through joint simulation data of Trucksim/Simulink.Based on the design of the three-dimensional phase space analysis method concerning the center of gravity lateral deviation angle,yaw rate,and vertical load transfer coefficient,the real-time stability state of the vehicle is determined.The output feedback robust H_∞controller is designed using AFS control and AFS/DYC hierarchical control according to different vehicle driving conditions.Furthermore,the extensible control method is utilized to compensate for the control output of the front wheel steering angle and lateral yaw moment to ensure the robustness of the controller under different working conditions.The design of the extensible H_∞controller is completed based on the use of the adhesion coefficient.The effectiveness of the stability control strategy is verified by joint simulation of Truck Sim/Simulink and hardware-in-the-loop experiments,and the superiority of the dynamic stability domain in phase space is demonstrated through a comparison ofβ-(?)-LTR phase space judgment andβ-(?)phase plane judgment in simulation.The simulation and experimental results show that compared with the simple manipulation of the vehicle by the driver’s intention,the AFS/DYC hierarchical control strategy based on extensible H-infinity control can ensure the stability of the vehicle under different working conditions,especially on low-adhesion road surfaces,effectively reducing the probability of traffic accidents in extreme working conditions.