基于图论的可重构制造系统重构策略

可重构制造系统(RMS)是针对零件族设计的既具有定制的柔性,又具有高生产率的制造系统。RMS通过重构来适应市场需求的变化。RMS的设计目标是基于重构条件下寻求制造系统在全生产周期内的系统成本最优。首先建立RMS的各生产周期成本模型、重构成本模型与全生产周期成本模型,构建RMS在各生产周期的组态有向图,利用Dijkstra算法与双向扫视算法求得RMS在各生产周期的最优成本组态与K-1个次优成本组态。根据所求得各生产周期的最优成本组态与K-1个次优成本组态,重构成本模型与全生产周期成本模型,计算上下生产周期各组态间的重构成本,并构建RMS全生产周期的重构策略有向图,再次利用Dijkstra算法与双向扫视算法求得 RMS全生产周期的最优重构策略与K-1个次优重构策略。最后用实例验证了方法的有效性与可行性。

RECONFIGURATING POLICY OF RECONFIGURABLE MANUFACTURING SYSTEMS BASED ON GRAPH THEORY

Reconfigurable manufacturing systems (RMS) are manufacturing systems designed for part family, which have both customized flexibility and high productivity. RMS adapt to the fast market fluctuation by reconfigurating. The design objective of RMS is to find the optimal and sub-optimal cost configuration paths across the lifetime of manufacturing systems. First, the cost model for every production period of RMS, the reconfigurating cost model and the lifetime cost model of RMS are constructed. Second, the directed graphs of configurations of RMS at every production period are constructed. Finally, based on the directed graphs, the optimal and K-1 sub-optimal cost configurations of RMS at every production period are found out by using Dijkstra algorithm and double-sweep algorithm. According to the optimal and K-1 sub-optimal cost configurations of RMS at every production period, the reconfigurating cost model and the lifetime cost model of RMS achieved above, the reconfigurating costs between every configuration at the up-production period and every one at the down-production period are calculated, then the reconfigurating policy directed graph across the lifetime of RMS is constructed. Using the Dijkstra algorithm and double-sweep algorithm again, the optimal and K-1 sub-optimal reconfigurating policy across the lifetime of RMS is figured out. Finally, a case study illustrates the developed method is valid.