| With the rapid growth of vehicle ownership and road traffic flow,the existing road network facilities can hardly meet the growing traffic demand,resulting in the increasingly serious problem of urban traffic congestion.As an important place to gather and evacuate the traffic flow,whether the control mode of intersection is scientific and reasonable directly affects the road traffic safety and travel efficiency.The traditional signal-controlled intersection avoids traffic conflicts by means of phase prohibition,which is a very inadequate use of intersection space-time resources and difficult to efficiently divert random traffic flow,resulting in increased traffic delays.In the vehicleinfrastructure cooperative traffic environment,the integrated intelligent transportation technology based on vehicle,road and cloud communication provides a new platform and opportunity for realizing efficient,safe and green urban traffic control.Therefore,it is of great research value and practical significance to explore how to realize the intelligent transformation of intersection control mode under the empowerment of new technologies,so that the intersection space-time resources can be fully and efficiently utilized.Firstly,this paper constructs the intelligent intersection control system composed of on-board units,roadside units and cloud control centers,designs and plans the system functions from the basic data perception module,information exchange sharing module and control decision application module,and expounds in detail the multi-source information intelligent perception technology,V2 X communication technology and data fusion processing technology involved in the system application.The internal conflict of intersection is analyzed from the micro level,the corresponding relationship matrix of vehicle conflicts at intersection is established,and the sequence of vehicle traffic conflict zone at intersection is summarized.Secondly,based on the gap control theory,the control concept of intelligent connected vehicles alternately passing through the intersection conflict zone is proposed.According to the requirements of control functions,the road sections in the intersection area are divided into lane change area,regulation area and passing area,and the conflict resolution strategy of vehicle-infrastructure cooperative intersection is proposed,and the driving gap control model for conflict vehicles between straight and straight,straight and left-turn,left-turn and left-turn is constructed.Then,the space-time gap allocation mechanism of intersection is analyzed,the vehicle traffic time axis of vehicle-infrastructure cooperative intersection is established,and the vehicle traffic time normalization method is designed and formulated.In order to ensure driving safety and improve the traffic efficiency of the intersection,the speed control method based on the dynamic allocation of space-time gap is proposed,and the vehicle following control model and conflict collision avoidance model are established,so that the vehicle can adjust speed in advance in the section of the regulation area to achieve the optimal safety speed for passing through intersection without collision and stop,so as to realize the full utilization of the space-time resources of the intersection.Finally,the simulation environment is redeveloped by using MATLAB and VISSIM COM interface technology,and the vehicle-infrastructure cooperative intelligent control intersection and traditional signal-controlled intersection are simulated under the conditions of traffic flow with different saturation,and the travel time,delay,fuel consumption and pollutant emission of vehicles passing through the intersection are selected as evaluation indicators to compare and analyze the intersection control effects under different control modes from three aspects of efficiency,economy and environmental protection.The simulation results show that: under the conditions of traffic flow with different saturation,the intelligent control method of vehicle-infrastructure cooperative intersection designed in this paper can optimize and dredge the random traffic flow,greatly improve the traffic efficiency of straight and left-turn vehicles at the intersection,and effectively reduce vehicle fuel consumption and the emission of various pollutants;and as the traffic flow gets closer to saturation,the benefits of vehicle-infrastructure cooperative intelligent control intersection in all aspects will be improved more significantly.At the same time,compared with the existing green wave speed guidance strategy,the method in this paper is no longer limited by the constraints of signal timing.It can provide more fragmented and discrete safe passage gaps for intelligent connected vehicles at intersection,and provide reference for the development and transformation of intelligent and refined urban traffic control in the future. |
