Longitudinal control model for connected autonomous vehicles influenced by multiple preceding vehicles
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摘要: 为了更好地模拟智能网联车辆(CAV)的跟驰特性, 在纵向控制模型(LCM)的基础上考虑V2V环境下多辆前车速度和加速度的影响, 构建了智能网联环境下的纵向控制模型(C-LCM); 对LCM和C-LCM进行稳定性分析, 比较了2个模型的交通流稳定域, 确定了不同通信距离时C-LCM对交通流稳定域的影响; 设计数值仿真试验对加速和减速的常见交通场景进行模拟, 分析了在V2V通信条件下CAV的跟驰行为特征; 仿真分析了CAV不同通信距离以及不同渗透率影响下的交通流安全水平; 构建了包含不同CAV渗透率的混合交通流基本图模型。研究结果表明: 交通流稳定域随着考虑前车数量的增多而增大, 当只考虑1辆前车时, 前车与本车的间隔越远, 车辆速度系数对C-LCM稳定域的影响越大; C-LCM可以提前对多前车的行为做出反应, 更好地模拟CAV的动力学特征, 在减速情景中速度超调量从0.15减少为0.08, 最大速度延迟时间由7.5 s缩短为4.9 s, 在加速情景中速度超调量从0.07减少为0.04, 最小速度延迟时间由3.5 s缩短为2.6 s; 随着CAV渗透率的提升, 交通流的安全水平不断提升, 当通信范围内有4辆CAV时, 交通流的安全性能达到最高, 其TIT和TET指标的最大减少量分别为57.22%和59.08%;随着CAV渗透率的提升, 道路通行能力从1 281 veh·h-1提升为3 204 veh·h-1。可见, 提出的C-LCM可以刻画不同车辆的跟驰特点, 实现混合交通流建模, 并降低混合交通流的复杂性, 为智能网联车辆对交通流的影响分析提供参考。Abstract: In order to better simulate the car-following characteristics of connected autonomous vehicles(CAV), based on the longitudinal control model(LCM), the LCM in the connected autonomous environment(C-LCM) was constructed considering the influences of speed and acceleration of multiple preceding vehicles in V2 V environment. The stabilities of LCM and C-LCM were analyzed. The stability regions of two models were compared, and the influence of C-LCM on the traffic flow stable region under different communication distances was determined. Numerical simulation was designed to simulate the common traffic scenarios including acceleration and deceleration, and the car-following behavior characteristics of CAV in V2 V environment were analyzed. The traffic flow safety levels with different communication distances and penetration rates of CAV were analyzed with simulation. A fundamental diagram model of mixed traffic flows with different penetration rates of CAV was constructed. Analysis result shows that the traffic flow stability region increases with the increase of considered preceding vehicles numbers, and when only considering one preceding vehicle, the longer the distance between the preceding vehicle and ego vehicle, the bigger the influence of velocity coefficient on the C-LCM stability region. The C-LCM can respond to the behaviors of multiple preceding vehicles in advance and simulate the dynamics characteristics of connected autonomous vehicles better. In the deceleration scenario, the speed overshoot decreases from 0.15 to 0.08, and the maximum speed delay decreases from 7.5 s to 4.9 s. In the acceleration scenario, the speed overshoot decreases from 0.07 to 0.04 and the minimum speed delay decreases from 3.5 s to 2.6 s. With the increase of CAV penetration rate, the safety level of traffic flow increases. The highest safety level is achieved with four CAVs in communication distance, and the TIT and TET indexes decrease by 57.22% and 59.08%, respectively. With the increase of CAV penetration rate, the highway capacity increases from 1 281 veh·h-1 to 3 204 veh·h-1. So the proposed C-LCM can describe the car-following characteristics of different vehicles to achieve the modeling of mixed traffic flow, decrease the complexity of mixed traffic flow, and provide a reference for the impact analysis of CAV on traffic flow.
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表 1 LCM仿真参数取值
Table 1. Values of LCM simulation parameters
参数 vf/(m·s-1) An/(m·s-2) Bn-1/(m·s-2) 取值 30 4 4 参数 bn/(m·s-2) l/m τn/s 取值 4 7 1 表 2 通信距离内CAV数量对TET指标的影响
Table 2. Impacts of CAV numbers in communication distance on TET index
通信距离内CAV数量 不同d0(s)取值的D1计算值 1.0 1.5 2.0 2.5 3.0 0 436.00 441.72 446.13 450.49 454.60 1 216.72 227.73 233.64 238.44 243.24 2 194.42 206.41 212.95 217.93 222.72 3 192.63 200.88 206.49 210.91 215.46 4 186.54 194.47 200.00 204.55 208.94 5 187.57 195.28 201.32 205.40 209.78 表 3 通信距离内CAV数量对TIT指标的影响
Table 3. Impacts of CAV numbers in communication distance on TIT index
通信距离内CAV数量 不同d0(s)取值的D2计算值 1.0 1.5 2.0 2.5 3.0 0 430.00 650.05 871.99 1 096.00 1 322.40 1 201.32 313.23 424.61 546.59 667.03 2 183.34 284.04 388.93 496.61 606.70 3 180.49 279.02 380.90 485.26 591.81 4 175.95 271.36 370.07 471.25 574.60 5 177.64 273.49 372.63 474.22 578.00 表 4 不同CAV渗透率对TET指标的影响
Table 4. Impacts of CAV with different penetration rates on TET index
CAV渗透率/% 不同d0(s)取值的D1计算值 1.0 1.5 2.0 2.5 3.0 10 365.08 368.03 371.56 387.76 393.98 20 334.99 345.00 352.53 368.75 372.95 30 313.18 318.36 323.02 327.33 331.61 40 298.30 304.59 318.41 322.89 337.35 50 283.80 296.17 305.96 315.40 321.78 60 265.33 276.82 290.64 297.01 302.29 70 248.31 264.93 279.78 287.22 299.58 80 225.66 243.29 258.12 262.52 276.73 90 203.94 215.61 223.51 223.96 232.20 100 186.54 194.47 200.00 204.55 208.94 表 5 不同CAV渗透率对TIT指标的影响
Table 5. Impacts of CAV with different penetration rates on TIT index
CAV渗透率/% 不同d0(s)取值的D2计算值 1.0 1.5 2.0 2.5 3.0 10 365.54 562.33 751.47 952.80 1 136.27 20 345.41 540.17 709.28 912.60 1 084.06 30 327.51 485.43 675.76 862.36 983.13 40 312.53 462.03 626.02 786.36 958.95 50 298.96 451.73 614.00 745.60 868.44 60 279.39 438.46 582.06 728.97 780.08 70 238.30 356.89 489.06 651.56 727.30 80 212.51 326.79 449.63 554.79 687.14 90 201.78 310.72 429.24 528.09 629.16 100 175.95 271.36 370.07 471.25 574.60 -
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