Study On Coordinated Control Of Urban Expressway Under Accident Condition Based On Synchronization Of Complex Networks

Traffic accident is one of the main reasons for the congestion of road traffic,especially urban expressway,which reduces the traffic efficiency,especially in the period of high demand for commuting.As an important part of the road traffic system in large and extra large cities,the relative closeness of expressways makes it more difficult to deal with accidents,the available routes of vehicles are limited,the scope of accident influence is expanded,and the characteristics of high speed and large capacity cannot be brought into play.Considering the short distance between adjacent ramps,the effect of single ramp regulation and main line speed limit is limited,the coordinated control of multi ramps under the accident becomes the main means.The existing coordinated control model of multiple on ramps has some shortcomings,such as redundant solution process,lack of feedback mechanism,not suitable for large-scale network,need to determine the control range in advance,etc.,and all of them do not involve the complex network theory and synchronous control of urban expressway under accident state.For this problem,based on the cell transmission model(CTM),this paper divides the upstream and downstream cells of the accident point,reconstructs the nodes,establishes the coupling model of complex network nodes of urban expressway under the accident,and determines the stability conditions of the system through the controller algorithm.The counterclockwise direction of the south-half ring in Tianjin City Expressway of China was used as the simulation object.This expressway segment begins at Binyue Bridge on Hongqi South Road and ends at Haijin Bridge at the junction of Heiniucheng Road and Kunlun Road.This paper studies the coordinated control of urban expressway under the accident,and puts forward a new control method,which mainly involves the following aspects:(1)The establishment of modified cell transmission model(mctm)for urban expressway under accident.Based on the analysis of traffic flow characteristics of urban expressway in the accident state,mctm with different cell length is established,and the upstream and downstream cells of the accident point are re divided to reconstruct the node.(2)The construction of node coupling model of urban expressway under accident.By combining CTM and complex network synchronization theory,the single node state transition model of urban expressway and the coupling model of urban expressway nodes based on complex network theory are constructed respectively.(3)Based on the complex network synchronization,the coordinated controller of urban expressway multi on ramp is designed.Considering the synchronization of complex networks,a coordinated control method of multi ramps,i.e.control by holding,is proposed.The controller is designed to determine the control parameters,such as feedback gain matrix,control range,etc.(4)Experimental analysis.The counterclockwise direction of the south-half ring in Tianjin City Expressway of China was used as the simulation object.This expressway segment begins at Binyue Bridge on Hongqi South Road and ends at Haijin Bridge at the junction of Heiniucheng Road and Kunlun Road.The traffic flow of urban expressway under the accident is simulated,and the control signals and global control signals are respectively applied in the control section,and the simulation results are compared with the results without control,so as to verify the Research Institute’s proposal The effectiveness of coordinated control strategy of multiple on ramps on Urban Expressway to alleviate traffic congestion and reduce the impact of accidents.