路段拥挤条件下的高速公路匝道协调控制方法

Coordinated control method for freeway ramp with congestion of road section

为了提高主线路段拥挤条件下匝道启发式控制方法的有效性,提出了一种改进的Bottle-neck控制方法,以获得平稳的控制过程和缩短的调节时间.首先,依据拥挤持续时间内交通流波阵面向上游移动的距离,应用Greenshields模型确定交通拥挤的影响范围.其次,根据高速公路匝道桩号及拥挤的影响范围,确定用于协调控制的匝道数;并将密度作为控制变量,准确描述路段拥挤下的交通状况.最后,通过对局部调节率和协调调节率进行优化,克服了Bottleneck控制方法超调量过大、调节时间过长的缺陷.基于宁杭高速实测数据的仿真结果表明,改进的Bottle-neck控制方法能够使调节时间减少70%,超调量减小75%.

To improve the effectiveness of heuristic control of ramp traffic on a congested roadway,an improved Bottleneck control method is proposed to obtain a stable control process and a shortened control time.First,the Greenshields model is used to determine the influence range of traffic congestion based on the distance that a shock wave travels upstream on the roadway in the congestion duration.Then,the number of ramps to be controlled coordinately is determined according to the mileposts of ramps and the influence range of traffic congestion.The traffic density is selected as the control variable to describe the congested traffic condition precisely.Finally,the levels of local control and overall coordinated control are optimized to overcome the control overshoot and extended control period of the traditional Bottleneck control method.The simulation results with traffic data measured on the Ninghang freeway reveal that compared with the traditional Bottleneck control method,the improved method can reduce the control time by 70% and decrease the overshoot by 75%.