Modelling and optimization for integrated scheduling problem considering spare parts production, batch transportation and equipment operation

Existing production scheduling research has made great effort to integrate multiple production-related actives to achieve efficient product supply, such as the integration of production and transportation, and the integration of production and equipment operation and maintenance (O&M). However, rare studies are executed to investigate the integration of production, transportation and O&M, which may lead to inefficient supply plans. Encouraged by this, we consider a novel integrated scheduling problem, in which two-stage hybrid flow shop scheduling for spare parts manufacturing, transportation scheduling of the third-party logistics (3PL) and operational strategies of complex equipment are considered simultaneously. To tackle it, a mixed-integer linear programming model is constructed to minimize total production costs, minimize transportation costs and maximize operational utility of the equipment. Furthermore, a two-stage memetic algorithm (TSMA) is designed for addressing the problem. It employs a five-layer encoding method for chromosome representation and three well-tailored initialization methods to generate a high-quality initial population. In the first optimization stage, some problem-specific operators, including three crossovers, two mutations, and an entity-oriented local search operator, are proposed to improve its search capability. Two cost-saving strategies devised in the second optimization stage are designed to further optimize the optimal Pareto solutions generated in the previous stage. Extensive experiments demonstrate the superiority of the proposed designs and TSMA in addressing the considered problem. In addition, the necessity of integrating production, transportation and equipment operation is verified through a set of comparison experiments. The study enriches integrated production scheduling theory, and provides methodological support for improving operational utility of complex equipment.