Research On Coordinated Torque Control Strategy Of Human-machine Co-driving Steering Assist System

With the rapid development of automobile technology,and constantly improvement of people’s living standards,cars have already become an indispensable means of transportation for the masses,But it also raises a number of safety issues,in order to reduce road traffic accidents,how to improve vehicle active safety become the research focus,and the driver assistance system technology can effectively reduce the number of traffic accidents,improve the vehicle’s road safety,therefore,driver assistance systems technology and collaborative research between driver and auxiliary system is of great significance.In the light of the synergy between the driver and auxiliary system steering control strategy and obstacle avoidance path planning method study,aimed at improving the driver and the auxiliary system of collaborative performance,reduce human conflict and the driver operating burden,and when confronted by unknown obstacles to planning the obstacle avoidance path,ensure the safety of the motion of the vehicle.The innovation points and main research contents of this paper are as follows:(1)The vehicle and road position tracking model based on driver preview was modified to ensure the correctness of the model in subsequent studies.At the same time,in order to study the collaborative interaction between the driver and the auxiliary system,a vehicle-vehicle closed-loop model including the vehicle model driver model vehicle position tracking model and electric power steering model was established.(2)Analyzed in the process of driving demand and auxiliary level,based on this proposed a man-machine coordinated control method based on correlation analysis,the state of vehicle and road information in the past a period of time,with probability and statistics methods to analyze the driver input torque and the correlation of auxiliary torque to judge the human-machine collaborative,coupled with the driver’s auxiliary man-machine steering control access between the demand distribution,improve the performance of man-machine coordinated,reduced the burden of the driver’s driving,ensure the vehicle stability and path tracking precision.(3)A real-time trajectory planning method for obstacle avoidance was proposed for the unexpected moving obstacles with uncertain motion.This trajectory planning method can plan the optimal trajectory according to the obstacle position state,obstacle avoidance constraint conditions and optimization objective function in real time.Finally,the planned optimal obstacle avoidance trajectory is used as the reference target trajectory for tracking under the human-machine cooperative predictive steering control method proposed in this paper,so as to ensure the vehicle’s driving safety when meeting unknown obstacles.The thesis verifies the research contents through simulation experiments under different working conditions.First of all,it not only proves the correctness of the modified vehicle position tracking model theoretically,but also shows that the modified vehicle position tracking model is correct and reliable in the simulation experiment.Secondly,it is verified that the proposed human-machine cooperative steering control method can reduce the driver’s driving burden and improve the vehicle stability and tracking accuracy according to the driver’s requirements.Finally,it is verified that the proposed trajectory planning method can plan the optimal obstacle avoidance trajectory and track it in real time,so as to ensure the safety of the vehicle when it encounters unknown obstacles,and form a cooperative predictive steering control strategy that integrates trajectory planning and tracking.