飞机货舱中非集装器的配载是重要的运输环节,而如何保障非集装器的配载,是亟须研究的重要内容。其中二维矩形切割排样问题是解决非集装器运输的重要理论方法。二维矩形切割排样理论在原材料切割、装箱等问题中有着广泛应用,但尚无很好...飞机货舱中非集装器的配载是重要的运输环节,而如何保障非集装器的配载,是亟须研究的重要内容。其中二维矩形切割排样问题是解决非集装器运输的重要理论方法。二维矩形切割排样理论在原材料切割、装箱等问题中有着广泛应用,但尚无很好的求解算法。该方法会因求解速度而拖累整个实际生产作业进度。因此,本文提出了二维切割排样的混合整数线性规划(Mixed-integer linear programming,MILP)模型,模型目标是以矩形板面积利用率和切割排样价值最大为目标,模型考虑了不超边界、不重叠、可正交旋转等限制。设计了启发式分组策略的求解算法:首先基于启发式把矩形块分组为不同组别的小矩形块,降低变量和计算规模;其次,采用混合整数规划精确算法对每个小矩形块进行切割排样。以经典Benchmark实验数据为例,将Gurobi分组与Gurobi、CutLogic2D、基于遗传算法和最低水平线算法的混合算法对比。实验结果表明,CutLogic2D综合求解质量和速度较好;Gurobi分组方法是一种启发式算法,总体上要稍差于CutLogic2D;遗传算法和最低水平线算法因是启发式算法且未使用分组策略,和Gurobi分别在部分算例上求解时间相对较长,达到了7200 s,这是无法接受的。展开更多
Cargo airdrop has long been one of the most important measures to deal with urgent immediate needs, such as providing as- sists in military operations and sending relief to disaster areas, just to name a few. Because ...Cargo airdrop has long been one of the most important measures to deal with urgent immediate needs, such as providing as- sists in military operations and sending relief to disaster areas, just to name a few. Because it is carried out during flight, it is necessary to investigate the influences of the drop process on flight characteristics to ensure successful execution of the task. This article mainly studies the modeling of flight systems in large flying transport planes with cargo moving in it. By buildi...展开更多
文摘飞机货舱中非集装器的配载是重要的运输环节,而如何保障非集装器的配载,是亟须研究的重要内容。其中二维矩形切割排样问题是解决非集装器运输的重要理论方法。二维矩形切割排样理论在原材料切割、装箱等问题中有着广泛应用,但尚无很好的求解算法。该方法会因求解速度而拖累整个实际生产作业进度。因此,本文提出了二维切割排样的混合整数线性规划(Mixed-integer linear programming,MILP)模型,模型目标是以矩形板面积利用率和切割排样价值最大为目标,模型考虑了不超边界、不重叠、可正交旋转等限制。设计了启发式分组策略的求解算法:首先基于启发式把矩形块分组为不同组别的小矩形块,降低变量和计算规模;其次,采用混合整数规划精确算法对每个小矩形块进行切割排样。以经典Benchmark实验数据为例,将Gurobi分组与Gurobi、CutLogic2D、基于遗传算法和最低水平线算法的混合算法对比。实验结果表明,CutLogic2D综合求解质量和速度较好;Gurobi分组方法是一种启发式算法,总体上要稍差于CutLogic2D;遗传算法和最低水平线算法因是启发式算法且未使用分组策略,和Gurobi分别在部分算例上求解时间相对较长,达到了7200 s,这是无法接受的。
基金National Natural Science Foundation of China (60134010)Aeronautical Science Foundation of China (2007ZD53053)
文摘Cargo airdrop has long been one of the most important measures to deal with urgent immediate needs, such as providing as- sists in military operations and sending relief to disaster areas, just to name a few. Because it is carried out during flight, it is necessary to investigate the influences of the drop process on flight characteristics to ensure successful execution of the task. This article mainly studies the modeling of flight systems in large flying transport planes with cargo moving in it. By buildi...
