可重构制造系统的车间作业调度策略

提出了一种实用的分层调度策略 ,通过对制造系统组织的重构 ,以最小作业生产延迟和最大系统设备利用率为目标产生可行的次优调度方案 .该策略分 3个阶段 :首先 ,采用增广拉格朗日松弛法获得复杂可重构制造系统的车间作业预调度方案 ,该方法能将复杂作业调度问题分解成多个任务层的子问题 ,通过求解子问题获得任务的作业时间和对应工序加工的生产设备类型 ;然后 ,对制造系统进行组织重构以形成多个虚拟制造单元 ,旨在使制造单元内的生产设备间物流传送 (由自动导航小车承担 )费用最小 ;最后 ,通过离散动态规划形成虚拟制造单元的生产作业调度次优可行方案 .通过数值仿真分析 ,该策略能针对快速变化的产品需求 ,有效地重构生产制造系统 ,产生次优的调度方案 .

Job-shop scheduling strategy in reconfigurable manufacturing systems

This paper presents a practical hierarchical strategy to reconfigure the layout of an reconfigurable manufacturing system (RMS) incorporated with multiple autom ated guided vehicles (AGVs), and to obtain a feasible schedule with minimum tota l tardiness and maximum machines utilizations. The strategy includes three stage s in sequence. At first stage, an augmented Lagrangian relaxation method is deve loped to obtain a preparatory job-shop scheduling. The method can decompose the scheduling problem subject to complex constraints into multiple subproblems at operation-level for the selection of operation beginning times and machine type s. Then the layout is reconfigured to fabricate virtual manufacturing cells with the goal to minimize material handling cost of AGVs. Finally the static schedul e in each virtual manufacturing cell is generated with discrete dynamic programmi ng. Numerical study demonstrates that manufacturing systems of practical sizes c an be effectively and rapidly reconfigured to accommodate production changes.