A Critical Path-Based Bi-Population Cooperative Coevolutionary Algorithm for Hybrid Lot-Streaming Flow Shop Scheduling Problem

Lot streaming, which combines lot splitting with overlapping operations, is used to reduce processing time and increase productivity in current manufacturing systems. This study focuses on the hybrid lot-streaming flow shop scheduling problem (HLFSP) and related subproblems, including lot planning and production scheduling. A mixed integer linear programming (MILP) model is proposed for the HLFSP to minimize the makespan of production processes. A critical path-based bi-population cooperative coevolutionary algorithm (CP-BCCEA) is proposed to simultaneously optimize sublot sizes, machine assignments, and sublot sequencing. The concept of critical jobs is defined by calculating the critical path of lot-streaming scheduling. The effectiveness and efficiency of CP-BCCEA are tested by experiments that compare it with state-of-the-art methods over a defined set of test instances.