交通流分支分析及拥堵缓解控制策略研究

The research of traffic congestion control has been developed rapidly in recent years. The essence of traffic congestion is a kind of branch behavior incurred by the loss of stability in the traffic flow from the perspective of system stability. Therefore, researching the bifurcation characteristics of traffic flow and designing control schemes for unstable branch points can provide some new methods for relieving the traffic congestion. In this project, we study the bifurcation characteristics and nonlinear control of traffic flow from two aspects of basic theory and realization method. More precisely, we will address three key challenging issues as follows. Firstly, we will study the nonlinear mechanism problem of traffic flow based on the phase plane analysis, and then propose a phase plane analysis method to transform the traffic flow problem into the stability analysis problem of systems and to reflect unstable traffic characteristics such as congestion. Secondly, we will study the bifurcation dynamic behavior and the bifurcation conditions of traffic flow, and propose a bifurcation analysis method to investigate the stability catastrophic behavior initiated by the bifurcation in traffic flow and seek for the formation mechanism of traffic congestion. At last, we study the actual traffic flow bifurcation phenomena in China and the traffic congestion nonlinear control problem. Combined with the measured data, the internal reasons for the stability catastrophic behavior of traffic flow passed by the branch point are analyzed and the control strategies are proposed to alleviate the traffic congestion. This project will reveal the nonlinear characteristics and formation mechanism of traffic flow phenomena from a new perspective and explore reasonable traffic control methods to provide the theoretical foundation and scientific basis for preventing and alleviating traffic congestion.

交通拥堵控制的研究近年来得到了迅猛发展。从系统稳定性角度讲，交通拥堵出现的实质是交通流失稳引发的一种分支行为，因此通过研究交通流的分支特性，针对不稳定分支点设计控制方案可为缓解交通拥堵提供新思路。本项目从基本理论和实现方法两个角度研究交通流分支特性及非线性控制的三个基础科学问题：研究基于相平面分析的交通流非线性机理问题，提出一种相平面分析方法，将交通流问题转化为系统的稳定性分析问题，突出反映拥堵等不稳定交通特性；研究交通流分支动力学行为及分支条件，提出一种分支分析方法，揭示交通流中由分支引发的稳定性突变行为和交通拥堵的形成机理；研究我国实际交通流分支现象及交通拥堵非线性控制问题，结合实测数据分析交通流经过分支点稳定性突变的内在原因，提出缓解交通拥堵的控制策略。本项目的研究从全新角度揭示了交通流现象的非线性特性和形成机理，探索合理的交通控制方法，为预防和缓解交通拥堵提供理论基础和科学依据。

本项目集中考察基于相平面分析的交通流非线性机理问题、宏观交通流模型的分支分析问题和实际交通流分支现象及交通拥堵非线性控制问题。相平面分析部分主要研究：交通流非线性现象的相平面分析方法；边走边停、冲击波、稀疏波等典型交通现象的相平面分析；西宝高速匝口不同输入输出相平面分析。分支分析部分着重讨论：一类速度梯度宏观模型的交通流分支分析；一类密度梯度宏观模型的交通流分支分析。实际现象部分重点考察：实际交通中Hopf分支引发的交通流现象分析；实际交通中鞍结分支引发的交通流现象分析；针对不稳定分支点设计拥堵缓解控制方案。项目研究取得一系列重要成果，对揭示交通流现象的非线性特性和形成机理，探索合理的交通控制方法，预防和缓解交通拥堵有重要参考价值。依托本项目，课题组已在相关领域发表论文22篇，其中SCI期刊论文10篇。