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

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.