Coordinated Optimization And Control Theory Of Urban Network-wide Traffic Signal

There are several feasible methods which can alleviate the urban traffic problems,such as roads planning and constructing,traffic signal control and intelligent traffic route guidance,by far.According to the current development condition of big cities in our country,it is apparent that there is no way to lighten urban traffic burden only by constructing more roads,because of its high cost and the urban land resources are limited.As mentioned in many literatures,urban traffic signal control and intelligent traffic route guidance can significantly improve the utilization rate of existing traffic facilities,so as to promote the vehicle travel efficiency and reduce traffic accidents.Ultimately,the urban traffic problems are due to the fact that existing traffic network and traffic control technologies could not cover the growing traffic demand.Therefore,it is suggested to do some foreseeing traffic network planning based on existing network and design more effective traffic route guidance strategies,real-time traffic signal cooperative control technologies.Urban traffic signal control has been gone through a long development process from single intersection control and arterial coordination intersection control to area coordination intersection control.At present,urban traffic coordination control has become a hot research area of traffic signal control,but there are still many problems needed to be solved urgently.Different from single-intersection control and arterial coordinated control,the coordinated control of urban area aims to realize the coordination of each region in urban area and achieve the optimization of the total urban area.Firstly,a brief review of urban traffic signal control is presented in this thesis;Secondly,the spatiotemporal variation attributes of traffic flow between intersections based on existing traffic flow model is analyzed;Thirdly,the thesis adopts several advanced control and optimization methods to solve those traffic problems,such as single-intersection control,arterial control and area coordinated control.The concrete contributions of the thesis are given as follows.In the part of abstract,a brief review of urban traffic control is presented,and then attention is focused on discussing the meaning of area coordinated traffic control.In order to demonstrate this point,the research status of urban traffic coordinated control in domestic and overseas is summarized in detail in this thesis.Based on what we discussed above,it is easy to conclude that the research of urban traffic coordinated control is of significant importance.In the second part of this thesis,some basic traffic signal control theories and concepts are introduced carefully,which are the theoretical basis of the subsequent part of this paper.Several crucial traffic parameters and its design theories are also introduced in detail,and the thesis also focuses on the effect of relative assessment criteria on traffic signal control,such as delay time,travel distance,stop times and number of vehicles per unit of time.To solve large-scale urban traffic signal control problem more commendably,the modeling theories of traffic flow are also discussed in this part.Compared with others modeling methods,Store-and-Forward model(SFM)is more suitable for our control method.Serval traffic control methods based on SFM are discussed in this part,which are of vital reference value.Finally,the design of single-intersection control,arterial traffic control and area coordinated traffic control,and the difference between each other are analyzed carefully.In the subsequent part of this paper,based on the basic theories presented in first two part of this article,the SFM model and MPC control theory are applied to traffic signal coordinated control.Firstly,the history of development and basic concepts of MPC are reviewed.Then,it is naturally to apply those existing models and theories to solve the traffic signal control problems,like single-intersection control,arterial traffic control and area traffic coordinated control.In the end,the results of simulation are presented to demonstrate the effectiveness of our control method.Finally,the concept of distributed optimization that can be used to deal with the problem of large-scale urban traffic signal control is introduced.By means of distributed optimization,the original centralized urban traffic signal optimization problem can be solved more flexible and robust.In this way,the online computational complexity will be reduced significantly.Firstly,a brief review of distributed optimization and control is discussed,and some important characteristics of distributed optimization are presented in detail.To solve the distributed traffic signal optimization problem effectively,serval distributed algorithms are compared and the suitable method-Accelerated Distributed Augmented Lagrangian(ADAL)algorithm is chosen.Finally,the thesis carefully designs an area traffic signal control simulation example of distributed MPC,which is used to show the effectiveness of the provided algorithm.