| In the mixed traffic flow of the basic road section of freeway composed with connected and automated vehicles and human-driven vehicles(referred to as freeway mixed flow),the lane change decision of connected and automated vehicle plays a decisive role in its lane change behavior.Unreasonable lane change behavior will not only interfere with the smooth operation of traffic flow,but also reduce the efficiency of road transportation.Therefore,it is of great practical significance to study on lane change behavior decision of connected and automated vehicles in mixed flow environment.In this thesis,based on the basic road section of freeway under mixed flow,study on the autonomous lane change behavior and cooperative lane change behavior of connected and automated vehicles,and a lane change model of connected and automated vehicle under mixed flow on the basic road section of freeway is proposed.This thesis focuses on two parts: the autonomous lane-change decision model of connected and automated vehicles and the cooperative lane change control model of connected and automated vehicles.(1)Aiming at the autonomous lane change scene of connected and automated vehicle under the mixed flow of freeway,the influence of the vehicle types of the leading vehicle in the expected lane and the original lane on the lane change behavior of connected and automated vehicle is investigated,and the connected and automated vehicle are classified according to this autonomous lane change scene type.Based on the influence of the lane change behavior of connected and automated vehicle on the motion state of the following vehicles,the lane change benefit function of connected and automated vehicle is constructed,and a decision model for autonomous lane change of connected and automated vehicle based on the total benefit of autonomous lane change is proposed.Combined with the autonomous lane change scene in the mixed flow of the freeways,the human-driven vehicle gap acceptable lane change decision model and the connected and automated vehicle MOBIL lane change decision model are selected as the simulation reference experiments to conduct autonomous lane change decision simulation experiments.The simulation result shows that the lane change time of the human-driven vehicle with lane change decision model is shorter than that of the connected and automated vehicle lane change decision model.The MOBIL lane change decision model of connected and automated vehicle fails to consider the influence of the type of leading vehicle in the expected lane on the motion state of connected and automated vehicle after lane changing,which makes the car-following control after connected and automated vehicle lane change uncertain and difficult,which is negative impact on traffic flow.The proposed autonomous lane change decision model for connected and automated vehicles can accurately associate the leading vehicle types in the expected lane and the original lane in mixed traffic flow,and has a more reasonable lane change behavior decision.In addition,by parametric analysis of the distance between leading vehicle and following vehicle in the expected lane shows that when the distance between leading vehicle and following vehicle in the expected lane is small,the decision result of the proposed connected and automated vehicle autonomous lane change decision model is no lane changing,which avoids the negative impact of unreasonable lane change behavior on traffic flow.When the distance between leading vehicle and following vehicle in the expected lane is large and the lane change behavior of connected and automated vehicle does not have a significant negative impact on traffic flow,the proposed lane change decision model has more lane change time than the MOBIL lane change decision model.Simulation results verify the rationality and effectiveness of the proposed decision model for autonomous lane change of connected and automated vehicle.(2)Aiming at the collaborative lane change scene of connected and automated vehicle in the mixed flow environment of freeway,the relationship between the initial distance of subject vehicle(connected and automated vehicle)and cooperative vehicle(the first following vehicle in the expected lane)and the equilibrium distance was analyzed,and the speed control models of subject vehicle and cooperative vehicle under the collaborative lane change decision is constructed respectively.It is used to predict the motion state of subject vehicle and cooperative vehicle in the process of cooperative lane change.Based on the benefit function of autonomous lane change of connected and automated vehicle,the benefit function of cooperative lane change of connected and automated vehicle is established,and the decision model of cooperative lane change of connected and automated vehicle is constructed.Based on the collaborative lane change decision model of connected and automated vehicle and the speed regulation model under collaborative lane change decision model,the collaborative lane change control model of connected and automated vehicle under the mixed flow environment of freeway is constructed.Combined with the collaborative lane change scene of connected and automated vehicle in the mixed flow environment of freeway,the proposed autonomous lane change decision model of connected and automated vehicle is taken as the reference experiment to conduct a comparative simulation experiment of the collaborative lane change control model of connected and automated vehicle.The simulation results show that in the mixed flow environment of freeway,compared with the autonomous lane change behavior of connected and automated vehicle,the collaborative lane change behavior of connected and automated vehicle has less influence on the acceleration speed and speed of the following vehicle behind the expected lane,making the time for traffic flow to recover to the stable state shorter.At the same time,under the condition that the traffic flow is not greatly disturbed,the cooperative lane change time of connected and automated vehicle is longer than the autonomous lane change time.The simulation results verify the rationality and effectiveness of the proposed connected and automated vehicle collaborative lane change control model. |
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