基于综合经济效益优化的匝道合流车辆编队策略

Ramp merging platoon formation strategy based on comprehensive economic benefits optimization

研究高速公路匝道车辆序列合并编队的优化协调问题,根据环境参数优化设置合并阈值,减少排放、节约编队成员时间成本和燃油资源.首先,针对合流中自由车辆与已有车队同时存在的复杂场景给出阈值编队方案,结合车辆运动学和全期望公式,计算与编队阈值相关的特征值:1)队列规模概率;2)时间增量期望;3)队列间距期望.然后,根据特征值分析各经济成本增量,并利用连续动力学状态方程的转换推导行驶约束安全集,建立基于阈值的优化编队模型,在安全性前提下最大化车辆队列的全程综合经济效益.最后,通过仿真对比所提出策略与直接编队策略,验证所提出策略能够提升综合经济效益并满足计算实时性要求.仿真结果表明了巡航距离以及车辆密度对编队的综合经济效益影响较大.

A coordinated platoon formation technique with a threshold is developed to coordinate the vehicle sequences to merge on the highway ramp.The merge threshold based on environmental parameters is optimized to reduce emissions,save time costs and fuel resources.First of all,this paper gives a threshold platoon formation scheme to overcome the complexity induced by the coexist of free vehicles and existed platoons.Then combining the vehicle kinematics and full expectation formula,the paper calculates the characteristic values related to the formation threshold:1)the likelihood of the platoon size,2)the expectation of time increments,and 3)the expectation of platoon spacing.Secondly,the economic cost increment is analyzed according to the characteristic values,and the set of the driving constraint safety is derived by the transformation of the continuous dynamic state equation.Then the platoon formation optimization model based on the threshold is built,which maximizes the comprehensive economic benefits with the guarantee of safety.Finally,the proposed strategy is compared with the direct platoon formation technique in the simulation,which demonstrates that the proposed strategy can increase the comprehensive economic benefits and meet the real-time computing requirement.In addition,according to the simulation results,cruising distance and traffic density are the key factors affecting the comprehensive economic benefits of the platoon.