Research On The Merging Strategy And Acceleration Zone Trajectory Planning And Tracking Control Of Intelligent Connected Vehicles On High-speed Ramps

With the continuous development of intelligent connected vehicle technology,intelligent connected vehicles can achieve information collection,sharing,and collaborative control through intelligent sensing technology and vehicle communication,thereby improving traffic safety and efficiency.The existing merging strategies and subsequent trajectory optimization for high-speed ramp entrances mainly consider the optimal energy consumption of vehicles,with few studies focusing on the optimal safety and stability of vehicles.Taking the expressway ramp entrance as the research object,this paper studies the merging strategy of intelligent network vehicles when merging at the high-speed ramp entrance and the trajectory planning and tracking control of the acceleration zone after merging.The main work of this paper is as follows:(1)A virtual mapping merging strategy considering the distance between safety car is proposed to solve the safety problems of the merging strategy based on virtual mapping at high-speed ramp entrances,such as the close distance between the main and ramp vehicles after vehicle mapping.In the process of merging,the ramp vehicles are mapped to the main road virtually.According to the current vehicle speed and the distance to the merging point,the sequence of the main and ramp vehicles arriving at the merging point is judged.When a vehicle arrives at the merging point,the distance between the two workshops at this time and the distance between the safety car are compared to determine whether there is a collision risk.If there is a risk,the speed is adjusted according to the vehicle position.If there is no risk,Plan the vehicle speed so that all vehicles have the same speed as those on the main road when reaching the confluence point.By considering the optimization of the virtual mapping convergence strategy by considering the distance between safety car,vehicles can safely achieve convergence.(2)A method for optimizing the velocity trajectory of the acceleration zone based on minimum Snap has been proposed.Vehicles entering the acceleration zone after merging have the same speed,forming a stable queue of vehicles,and optimizing the speed of vehicles in the merging acceleration zone.Firstly,establish an objective function for minimizing acceleration,then consider minimizing the combination of acceleration and Jerk,and set weight values to analyze it.Finally,consider minimizing the combination of acceleration,Jerk,and Snap.Similarly,design weights to analyze it.Design simulation experiments to validate the fuel economy and ride comfort of various speed optimization methods.Considering Jerk and Snap’s speed optimization method,the fuel economy of the vehicle can be reduced by 0.023L/100 km,while improving vehicle comfort.(3)Based on model predictive control algorithm,track and control the optimized vehicle trajectory in the acceleration zone.Taking vehicle yaw angle and speed as control variables,with the goal of trajectory tracking accuracy and stable changes in control variables,and adding restrictions on vehicle safety and actual acceleration in high-speed road acceleration scenarios,the system continuously solves the optimal control variables to achieve tracking of optimized speed trajectories.A joint simulation platform of Car Sim and MATLAB was built,and the simulation results showed that the designed controller has good tracking control effect,small tracking process error,high control accuracy,and meets the requirements of vehicle tracking control in the acceleration zone.