Study On Coordinated Control Of Freeway Based On Synchronization Of Complex Networks

With the development of social economy,freeway has become an indispensable part of urban road traffic system.When the traffic demand is high,traffic congestion is easy to occur,and the vehicles on the road can not dissipate for a while,forming a road bottleneck.If the upstream traffic demand is greater than the remaining capacity of the bottleneck section,the queuing of vehicles will occur upstream of the bottleneck section,increasing the travel time of vehicles,resulting in serious economic losses.Lost.Highway congestion has become a serious problem worldwide,whether from the economic,security,or environmental point of view,improve traffic congestion,improve traffic capacity is an important issue to be solved.At the same time,how to use complex network and its synchronization theory to study the control of traffic flow,so as to provide decision support for traffic management has become a new trend of discipline development.Multi on-ramps control is the main measure of restraining traffic congestion and improving traffic efficiency to achieve energy saving and environmental protection.Existing control models have some shortcomings,such as complicated solving process,depending on predictive accuracy,lack of feedback mechanism,difficulty in large-scale network application,or need to specify the scope of coordinated control signal in advance.Models involving complex network system theory and its synchronization control do not involve the study of multi on-ramps coordinated control of freeway.Therefore,this paper proposes a freeway node coupling model based on Cell Transmission Model(CTM)and complex network theory,and verifies its synchronization.Taking Beijing Sixth Ring Road as the research object,this paper studies the coordinated control system of freeway under congestion and puts forward new control methods,which mainly involve the following aspects:(1)Establishment of Modified Cell Transmission Model(MCTM)for freeway section.Based on the traditional CTM and the traffic flow characteristics of expressway,MCTM with different cell lengths is established.(2)The establishment of freeway node coupling model.On the basis of MCTM and combined with the characteristics of complex network,the whole freeway network is considered as a system,and the state transition model of single node of freeway is established respectively by taking the cell of on-ramp,on-ramp and a section of main line connected with it as a subsystem.The single node state transition model and the highway node coupling model based on complex network are established respectively.(3)Design of multi on-ramps coordination controller for freeway based on complexnetwork synchronization.This paper presents a new method of multi on-ramps coordination control,which is different from the traditional on-ramps coordination control method,namely,on-ramps coordination strategy based on drag control of complex network synchronization.A drag controller for network synchronization is designed.The structure and working principle of the controller are introduced in detail,and the stability conditions of system synchronization are deduced.The feedback gain matrix shows the effectiveness of the coordinated control strategy based on pinning control.(4)Experimental analysis.Combined with the traffic flow simulation experiment of Beijing Sixth Ring Road,the multi on-ramps coordinated control of freeway under congestion condition is studied.No-control Signal,Pinning Control Signal,Pinning Control and Variable Speed Limit Control Signal,Global Control Signal and CORDIN Control Signal were applied to the experimental subjects,respectively.Density,total travel time and control time are compared to verify the effectiveness of the proposed this control method.