考虑低碳的多台轮胎式龙门吊路径优化问题

在港口集装箱作业中,龙门吊是重要的港口资源。如何更加合理地调度轮胎式龙门吊对减少港口碳排放和降低运营成本有重要意义。考虑到轮胎式龙门吊在空间上的不可跨越性及其他约束条件,根据装卸过程中所产生的移动碳排放、装卸碳排放和准备碳排放3种排放源,建立了轮胎式龙门吊调度的混合整数规划模型,目标是使轮胎式龙门吊的碳排放量达到最小。由于混合整数规划求解的复杂性,设计龙门吊初始路径策略并运用模拟退火算法求得近似最优解。通过算例实验,从路径长度、碳排放总量和运行效率3个方面对新方法的效果进行评价。相比于最短路径优化方法,新方法路径长度增加8.82%,运行时间仅增加0.21 s,碳排放总量减少3.30%,在保证龙门吊工作效率的前提下,有效地解决了龙门吊低碳路径问题。相比于经典遗传算法与蚁群算法,新方法的预测精确度分别提高1.13%和2.24%,运行效率分别提高9.82%和5.92%。 

Routing Optimization of Multiple Rubber-tired Gantry Cranes Considering Carbon Emission

Rubber-tired gantry cranes (RTGs)are important resources in container terminals.It is essential to schedule multiple RTGs effectively so as to reduce both carbon emissions and operating costs.Based on the feature of RTGs that they cannot cross each other,and other constrains,three sources of carbon emission during moving process, loading and unloading process,and preparing process are taken into consideration.A mathematical model of route pro-gramming for RTGs is developed to minimize the carbon emissions.For the computational complexity of a mixed integer programming model,a path strategy for RTGs is designed.A simulated annealing algorithm is applied to find the near-optimal solution.Numerical experiments are performed to evaluate the effects of new methods in three aspects:route lengths,total carbon emissions,and operational efficiency.Compared with the shortest path optimization method,this new model can increase the route lengths by 8.82%,while the runtime only increases by 0.21 s.The carbon emission re-duces by 3.3%.This method can guarantee working efficiency of RTGs,and effectively solve the problem of RTGs rou-ting with low-carbon emission.Compared with the genetic algorithm and the ant colony optimization,the accuracy of this proposed algorithm can improve the accuracy by 1.13% and 2.24%,respectively.In addition,the operational efficiency increases by 9.82% and 5.92%,respectively.