露天煤矿无人驾驶下交叉口协调通行策略研究

Study of coordinated access strategy at intersections in open-pit coal mines with unmanned trucks

为实现露天煤矿无人驾驶下交叉口无人卡车间协调通行,提出了基于间隙理论的交叉口协调通行策略。策略主要涉及车辆间冲突协调策略与车辆跟驰行为,冲突协调策略方面:拆解露天煤矿交叉口冲突类型为交叉冲突与合流冲突,分析交叉冲突加速协调与减速协调2种策略的判定条件,建立不发生交叉冲突的数学模型;理清合流过程中车辆间的跟驰关系,设计基于跟驰行为的合流冲突区域,明确不发生合流冲突的数学模型与协调策略;车辆跟驰行为方面:改进Krauss跟驰模型,实现车辆自适应车间安全距离要求;分析车辆间隙对间隙理论下的交叉口协调通行影响,提出满足协调通行的最小车辆间隙;策略验证方面:基于露天煤矿实际场景搭建了交叉-合流混合冲突的交叉口仿真模型,建立了协调策略-跟驰模型混合决策机制,以交叉口小时车流量密度、车辆速度与间隙变化作为评价指标,无高优先级车辆时的测试结果作为对照组。结果表明:初始车辆平均间隙达到3(4)倍及以上安全距离时,交叉冲突(合流冲突)协调通行表现较好,交叉口通行能力接近无冲突时的通行能力,车辆调整次数较少,证明了提出的交叉口协调通行模型在理论上存在可行性,反映了车流量密度是影响运输效率的因素,在满足生产的条件下,尽量采用大载重无人矿卡,减少无人化矿卡数量,降低设备间的干扰,是减少交叉口冲突,提高交叉口车辆通行能力的途径之一。

In realizing the coordinated access at intersections in open-pit coal mines with unmanned trucks,the intersection coordinated access strategy based on gap theory is proposed.Strategies are mainly concerned with intertruck conflict coordination strategies and truck following behavior.In the aspects of conflict coordination strategies,the study decomposes the conflict types into cross conflict and merging conflict.The judgment conditions of two strategies of acceleration coordination and deceleration coordination are analyzed in terms of cross-conflicts,and the mathematical model of no cross-conflicts is established.The following relationship between vehicles in the merging process is clarified,a merging conflict zone based on following behavior is designed,and a mathematical model and coordination strategy for no merging conflict is established.In the aspects of following behavior,the Krauss following model is improved,and the truck adaptive workshop is realized.For strategy validation,the intersection model of mixed crossing-merging conflict was built based on the actual scenario of open-pit coal mine,and the integrated decision mechanism of coordination strategy-following model was established,with the hourly traffic density at intersection,truck speed and gap changes as the KPIs,and the test results of no high-priority trucks as the control group.The results show that when the initial average truck gap reaches 3(4)times and above the safety distance,the crossing conflict(merging conflict)coordinated access performs well,the traffic density is close to the density when there is no conflict,and the number of truck adjustments is less,which proves the theoretical feasibility of the proposed intersection coordinated access model and reflects that the traffic density is a factor affecting the transportation efficiency.Under the condition of meeting production requirement,minimizing the number of unmanned mining trucks and reducing interference between equipment by using unmanned mining trucks with large payloads as far as possible is one of the ways to reduce intersection conflicts and improve intersection access capacity.