高速公路可变限速控制的数学建模与控制技术分析

Variable speed limit control (VSLC) has direct impacts on vehicle speeds. Conventionally VSLC aimed at traffic safety and did not contribute much to the improvement of traffic efficiency and relief of congestion. Congestion takes place when traffic demand exceeds road capacity, so flow/demand control is essentially relevant to congestion. This project proposes an innovative mechanism of regulating flow in the mainstream of freeways based on VSLC. It is very promising, in this mechanism, to convert VSLC into effective means of regulating flow and mitigating congestion in freeways. It is one of the major aims of this project to verify the feasibility of this mechanism. Available macroscopic traffic flow models rarely formulate the impacts of VSLC on traffic flow dynamics. This project intends to develop dedicated macroscopic models and study the stability properties of the models to the end of research in this project. VSLC strategies are designed in feedback control theory. The soundness of aforementioned mechanism is analyzed on the basis of the models and control strategies newly developed. Finally, the performance of the VSLC system is evaluated thoroughly via microscopic and macroscopic simulations while the stability of the overall control system is studied analytically. The work covered by this project is significant both theoretically and practically.

可变限速控制直接影响车流速度，故传统限速控制主要针对交通安全，对提升交通效率、缓解交通拥堵贡献不大。交通需求超出道路通行能力产生拥堵，因此拥堵控制的本质是需求/流量控制。本项目提出一种创新性的基于可变限速控制的高速公路主线流量调控机理，利用该机理有望将高速公路可变限速控制转变为调节流量、控制拥堵的有效手段。验证该机理的可行性是本项目的研究目标之一。现有宏观交通流模型很少考虑可变限速控制对交通流动态的影响，本项目拟建立服务可变限速控制研究的宏观交通流模型并研究新模型的稳定性；设计基于反馈控制原理的可变限速控制策略，以新建模型和控制策略为基础分析前述流量调控机理的可行性；通过微观与宏观仿真测试和评估可变限速控制系统性能，同时研究该控制系统的稳定性。本项目工作在理论和实践两方面都有重要意义。

本项目集中考察高速公路交通流动态建模和控制。建模部分主要研究高速公路交通拥堵的激波分析、拥堵环境下高速公路出口匝道锁闭的机理分析、道路交通流通行能力陡降的微观建模与仿真、高速公路出入匝道缺失流量估计、自动车队协同自适应巡航控制对宏观交通流性态的影响等重要问题。控制部分侧重讨论入口匝道下游存在远距离固定瓶颈时的匝道控制、拥堵条件下高速公路瓶颈通行能力陡降与高速公路交通控制效能的内在关联、匝道控制和可变限速控制的协同优化、车路协同环境下的可变限速控制、自动车队的协同自适应巡航控制等重要问题。项目通过数学分析和宏观及微观交通流仿真得到一系列重要结论，对高速公路交通监控研究与实践有重要指导意义。