Research On Vehicle Obstacle Avoidance And Tracking Control Based On Improved MPC

In recent years,people have paid more and more attention to the driving safety of automobiles.In order to reduce such accidents caused by human improper operation,most vehicles are equipped with intelligent driving assistance systems.When an obstacle appears in front of the car,the vehicle can avoid the obstacle by braking or actively turning.This paper studies the vehicle’s active steering obstacle avoidance and designs an improved MPC obstacle avoidance tracking control algorithm,which implements the vehicle’s obstacle avoidance behavior through steering intervention.Firstly,the vehicle model is established according to the vehicle body motion and the performance requirements of the controller,mainly including vehicle dynamics model and tire model.The simplified three-degree-of-freedom dynamic model is analyzed mechanically,and the control quantity and state quantity corresponding to the controller are obtained.Introduced several commonly used tire models,analyzed the force of the tire,and established a linear tire model.The model verification experiment shows that the established vehicle dynamic model can accurately describe the vehicle body motion,which provides a model basis for the design of the obstacle avoidance tracking controller.Then,the model predictive control theory is proposed,and the control layer of the obstacle avoidance planning of the model predictive controller is improved.A single obstacle simulation experiment was carried out on the original controller,and three important factors affecting the vehicle’s obstacle avoidance trajectory were analyzed.The least square method,BP neural network and ANFIS system are used to optimize the design of the obstacle avoidance function in the obstacle avoidance planning layer,and the trajectory planning of the vehicle’s variable obstacle avoidance weight coefficient is realized,so that the vehicle can adjust the obstacle avoidance according to the current speed and road conditions.Track.The tracking controller is introduced,and the tracking experiment of a circular arc trajectory proves that the designed tracking controller has good tracking ability.An obstacle avoidance + tracking double-layer controller is designed.By comparing the simulation results and cost function values of the three controllers under the same working condition,the optimal obstacle avoidance tracking controller is evaluated.Finally,a multi-obstacle simulation experiment under typical working conditions was carried out on the improved obstacle avoidance tracking controller,and the obstacle avoidance trajectories of the vehicles before and after the improvement were compared under different driving conditions.The experimental results show that the designed improved MPC controller can adjust the vehicle’s obstacle avoidance trajectory according to the vehicle speed and road conditions.While achieving vehicle obstacle avoidance,it can control the vehicle to return to the expected driving trajectory more quickly and smoothly,with better overall performance.