Hybrid algorithm of harmony search for dynamic parallel row ordering problem

Abstract In the context of an automated assembly line and flexible manufacturing, good layout planning of the production facilities aids in improving production efficiency and reducing production costs. The current research on the facility layout problems mainly focuses on the static ones with the fixed flow between facilities, including the parallel row ordering problem (PROP). Based on existing research on the PROP, in this study, we first investigate the dynamic parallel row ordering problem (DPROP), considering the flexibility of the production line. This study proposes a DPROP model and utilises it to verify some PROP examples less than 15 facilities and some global optimal solutions are achieved. In addition, the performance of the model in solving DPROP is verified on some new small-scale examples designed based on the PROP. Owing to the limited performance of the exact methods for DPROP, this study proposes a hybrid algorithm of harmony search and tabu search to solve large-scale problems, and this new algorithm performs better than some existing ones so that some new better solutions for the PROP examples are obtained. The algorithm is first utilised to solve the small-scale PROP and DPROP and the results are compared with an exact methods. Moreover, by evaluating the large-scale PROP between 30 and 70 facilities, the results are compared with those of the improved genetic algorithm and the population-based simulated annealing algorithm, thereby 28.8 % of the current optimal solutions are improved. Finally, the hybrid algorithm of harmony search and tabu search is utilised to solve the large-scale DPROP with 30 and 40 facilities, and some optimal solution sequences are presented.