Research And Realization Of MFD-based Cooperative Traffic Signal Control For Multiple Urban Regions

Traffic congestion problem has become one of the most crucial problems that restrict the development of urban economy and affect the progress of normal social life.Meanwhile,it is also the fundamental problem in the field of transportation research and applications.Traffic signal control,as one of the most typical traffic control and management methods,can alleviate traffic congestion to a great extend.It also provides the main research and development direction of the modern intelligent transportation systems.MFD-based urban traffic signal control is one of the advanced signal control method and has achieved certain results.Most of the existing research focus on the perimeter control of single or multiple traffic regions.However,considering the facts that tremendous amount of traffic flows interact and the whole urban traffic network forms a large-scale complex system,the cooperative signal control of traffic regions and the regulation of internal traffic flow within each region still deserves further investigation.In this thesis,resorting to the MFD properties of each individual traffic region,we provide a MFD-based cooperative traffic signal control method which may facilitate to improve the overall capacity of the traffic network by regulating the distribution of vehicles at the boundaries of different regions and within the region.The main work is as follows:1.To establish MFD models of multiple traffic regions.The real road network is partitioned into multiple homogeneous traffic regions in the first place.Then based on the real traffic data combined with simulation data,the existence of the MFD model of the urban road network is verified.Further,the MFD curve of each region is obtained and the MFD properties of each region is analyzed.2.To design the cooperative control objectives of multiple regions.Considering the actual traffic demands and the heterogeneity of the regions,a cooperative control strategy is proposed.Under this strategy,the determination of the cooperative signal control objectives w.r.t.each region is transformed into a constrained optimization problem to maximize the overall traffic capacity of the road network.The solution of the problem provides the best cumulative number of vehicles and the ideal road occupancy rate of each region and serves as the cooperative control objective of each region.3.To provide a cooperative traffic signal control method of multiple regions.Based on the control objective of each region,the PI feedback controller and the open-closed loop iterative learning controller are designed to achieve the perimeter control and the internal intersection signal control within the region,respectively.An integrated regulation scheme is given to further coordinate the signal timing plan.The simulation is performed according to real road network,and the control performances are evaluated.4.Design the urban traffic signal control simulation system.Perform a demand analysis of the system functions,design the overall architecture of the system,and establish interaction rules between traffic simulation software and traffic signal control software.Finally,design a visual interface to visualize the control effect.