Study On Feedback Control Method Based On Macroscopic And Microscopic Model Of Traffic Flow

With the rapid development of country economy and the speed-up process of urbanization,the question of traffic jam induced by the vehicle boosted sharply in the urban cities,which requires to propose feasible solutions for control research of traffic jams so that the urban traffic can be control.For the traffic transportation on roads,it not only enlarges the traffic capacity on the roads,but also it’s able to enhance the effectiveness of traffic operation on roads.The modern society had already been following the trend of intelligence.And the development of Intelligence Traffic System(ITS)is an important part of intelligent traffic.Based on the traffic macroscopicµscopic model and the development of ITS,this paper will focus on exploring control method of traffic flow in order to provide theory of traffic control.Thus,the main research works of this paper is as follow:(1)In terms of the optimal velocity model of traffic flow and feedback control theory,the mean-field feedback control model and the delay the mean-field feedback control model are proposed.The stability condition of two control models is obtained by conducting linear stability analysis.By the nonlinear analysis,the mKdV equation to depict kink-antikink density-wave is derived from the mean-field feedback control equation and the corresponding density-wave solution is obtained.When steady-state traffic flow is affected by a small perturbation and traffic system does not satisfy stability condition,the traffic system shows the stop-and-go traffic.At the moment,the mean-field feedback control and mean-field delay feedback control scheme are respectively exerted on traffic flow.By collecting speed and position data of all vehicles at the every moment,the effectiveness of suppressing traffic jam is estimated via determining the variation tendency from these data.And comparing with the effectiveness of two control model,the mean-field delay feedback control model of traffic flow has more effective to eliminate congested flow.(2)Considering the delay effect of drivers’ reaction time based on the lattice hydrodynamics(LH)model,the lattice hydrodynamics(LH)model with reaction time is proposed and the corresponding control strategy is constructed by upstream and downstream flow difference as a feedback control.The control system’s transfer function is obtained by conducting Laplace transformation.The stability condition of system is gained if the H∞ norm of transfer function is less than 1.It is verified that the delay effect of drivers’ reaction time is a significant factor to cause instability of traffic system via theoretical analysis and numerical simulation.With the help of feedback control,the system restored to be stable one from unstable state,which means the effective control is realized in congested system.(3)Based on the full-velocity difference model,the full-velocity difference with time-delay as control term is presented.The global stability and local stability analysis are carried out in this section.The research results indicate the full-velocity difference with time-delay is more efficient to suppress the traffic jam.(4)In this section,we will study the macroscopic hydrodynamic traffic equation by using the transform relation between microscopic and macroscopic model.Based on full-velocity difference model with time-delay,an anisotropic hydrodynamic traffic model is derived.The linear stability analysis of new macroscopic model is performed.The KdV-burgers equation is derived by nonlinear analysis and the corresponding density-wave solution is gained.Utilizing new macroscopic traffic model proceeds numerical simulation under periodic boundary.The results reveal the stable region is enhanced in low and high density of traffic flow,and unstable region is reduced.Finally,the research work of this dissertation is summarized.The future outlook for traffic flow control theory in ITS is given.