机器人制造单元集成式工艺规划与调度方法
The Methods of Robotic Manufacturing Cell Integrated Process Planning and Scheduling
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摘要: 文章针对机器人制造单元集成式工艺规划与调度(RMC-IPPS)问题,并考虑其加工次序柔性、加工柔性及工序柔性,提出了一种多层级线性编码的方法,该方法能有效地将RMC-IPPS问题的解用简单的数据结构表示,并实现对问题的整体求解。同时,针对毛坯件/半成品在单元中的转运问题,设计了一种基于贪婪思想的机器人调度策略,该策略每一步都选择当前的最优状态,使生产周期尽量不因搬运工序的存在而产生过多延滞。最后,设计出一种基于外部档案库的NSGA-Ⅱ算法(M-NSGA-Ⅱ),该算法通过外部档案库对非劣解进行二次搜索,以避免种群多样性趋于单一,并通过基准实例与实际生产应用算例对所提方法进行验证,并将改进后的算法与其它算法进行对比。结果表明,相较标准NSGA-Ⅱ算法,M-NSGA-Ⅱ算法的覆盖率为100%;相较文献中的算法,M-NSGA-Ⅱ算法具有更高的覆盖率。Abstract: Aiming at the robotic manufacturing cell integrated process planning and scheduling (RMC-IPPS) problem, considering the flexibility of features, processing and machines, a multi-level linear coding method is proposed. By using this method, the solution of RMC-IPSS problem can be expressed with simple data structure effectively, meanwhile, the two problems can be solved integrally. At the same time, for the sake of solving the transport problem of semi-finished products in the cell, the robots scheduling strategy based on the greedy algorithm is designed. In this strategy, each operation adopts the current optimal state to avoid the delay caused by the carrying works of production cycles. Finally, in order to increase the diversity of population, an improved NSGA-Ⅱ algorithm with external archives (M-NSGA-Ⅱ) is designed. The main idea of this algorithm is searching the noninferior solutions in the external archives. Furthermore, the approach is tested on benchmark instances and practical data instances. Compared with the standard NSGA-Ⅱ algorithm, the coverage of the M-NSGA-Ⅱ algorithm is 100%; moreover, the M-NSGA-Ⅱ algorithm has a higher coverage than others in the references.