临时养护区CMEM模型的微观仿真参数标定
Microscopic simulation parameter calibration of CMEM model for temporary maintenance zone

为了保证汽车尾气排放计算的准确性,对临时养护区微观仿真模型进行参数标定。以河南许尉高速公路某临时养护区为例,通过现场调查获取交通数据,建立VISSIM交通仿真模型。根据实测数据对交通量与交通组成等宏观参数进行标定,对期望速度、期望加速度采用特征点数值进行微观参数标定。利用正交试验法标定车头时距、跟车变量、进入跟车状态的阈值和振动加速度4种跟车模型参数。根据有效的仿真结果确定了期望速度与行驶速度之间的数值关系。利用有效的仿真数据结合CMEM模型进行临时养护区汽车尾气排放量计算,得到了基于路段平均速度的尾气排放计算公式。分析结果表明:宏观参数标定后的仿真速度与实测速度存在明显差异,客车与货车速度的平均相对误差分别为11.36%与35.12%; 结合微观参数标定后,仿真速度与实测速度的平均相对误差均控制在3%以内,客车与货车的期望速度分别为行驶速度的1.270、1.165倍; 仿真模型标定后的尾气排放量与实测值的相对误差均小于7%,模型标定效果显著。
In order to ensure the accuracy of automobile exhaust emission calculation, the parameters of microscopic simulation model for temporary maintenance zone were calibrated. The temporary maintenance zone located on the Xuwei Highway in Henan Province was taken as example, the traffic data were measured through field investigation. The VISSIM traffic simulation model was built. According to the measured data, the macroscopic parameters of traffic volume and traffic composition were calibrated, the microscopic parameters such as desired speed, desired acceleration were calibrated by using the values of feature points. Four parameters of car-following model including headway time, following variation, threshold for entering following status and vibration acceleration were calibrated by using orthogonal test. According to the valid simulation results, the numerical relationship between the desired speed and the running speed was determined. The emission of automobile exhaust was calculated by using the CMEM model with valid simulated data, and the calculation formulae of emissions were put forward based on average speeds. Analysis result shows the simulated speeds only calibrated by using macroscopic parameters are apparently different from the measured speeds, and the average relative errors of speeds for passenger car and truck are 11.36% and 35.12%. Combined with microscopic parameters calibration, the average relative error between measured and simulated speeds is lower than 3%. The desired speeds are 1.270 and 1.165 times of running speeds for passenger car and truck. After calibration, the relative error of simulated and measured emissions is less than 7%, and the calibration effect of model is remarkable. 11 tabs, 9 figs, 22 refs