The Methods of Robotic Manufacturing Cell Integrated Process Planning and Scheduling

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.