Research On Steering Stability Control And Road-feeling Design Of Steer By Wire Four-wheel-independent Steering System

The four-wheel-independent steering-by-wire system combines the steering-by-wire system and the four-wheel-independent steering system.It not only has the steering-by-wire system's advantages of flexibiliy and stability and adjustable road felling,but also can improve the flexibility of vehicle steering and the stable driving ability under the extremble conditions through the four-wheel-independent steering system,so as to achieve the goal of safe,stable and flexible driving.In this paper,the stability control,fault-tolerant control and road feeling control of the system are studied.Firstly,the system model,vehicle model,steering actuator failure model,driver model and steering stability control reference model are established,which will be used in the system controller design and simulation analysis.Then,in order to study the steering stability and fault-tolerant control of the system,the sideslip angle of the vehicle is estimated based on the unscented Kalman filter algorithm.Aiming at the highly redundant characteristics of the steering actuator of the four-wheel-independent steering electric wheel system,a layered control method is proposed,in which the motion control layer takes into account the uncertainty of the sideslip stiffness and speed of the front and rear wheels of the tire during driving The stability controller is designed based on ?control algorithm.In order to improve the stability of the vehicle under the limit condition,the optimal distribution method of the tire angle and driving force is studied considering the influence of the road adhesion coefficient and the tire load.Then,in the framework of stability control,according to the different types of actuator failure,redistribution of wheel angle and driving force is carried out to ensure the driving stability and achieve the purpose of actuator fault tolerance.Finally,in order to plan and control the road feeling of the steer by wire system,the mechanism and influencing factors of driving road sense are analyzed.The sensitivity of road feeling influencing factors is analyzed by machine learning algorithm,and the driving road feeling is trained and predicted by deep learning algorithm.Finally,considering the influence of variable transmission ratio,the road sense is designed based on H? control algorithm controller to provide real-time road feeling for drivers.Based on the above research,the model of the four-wheel-independent steering-by-wire system is established,the steering stability and fault-tolerant control system is constructed,and the road feeling planning and control method of the steering-by-wire system is proposed,which provides theoretical support for the research,design and development of the four-wheel-independent steering-by-wire system.