Scheduling methodologies for a flexible manufacturing cell with non-identical parallel machines and a robot

Abstract

This paper presents exact and heuristic methodologies for scheduling a flexible manufacturing cell (FMC) that consists of a number of non-identical parallel machines, a robot for loading and unloading, and a pallet handling system, which moves a batch of mixed parts into and out of the system. In the exact methodology, a nonlinear programming model is introduced to mathematically describe the problem and to determine optimal solutions for small size FMC problems. In the heuristic methodology, a customised tabu search (TS) utilising a greedy insertion algorithm (GI) is developed to identify efficient solutions with reasonable amount of computational time for large size FMC problems. The objective of this study is to minimise the total completion time, which includes robot loading, unloading and machining times of a batch of jobs delivered into an FMC system by a pallet. Randomly generated test problems are used to evaluate the performance of the proposed algorithms. The computational experiments show that the hybrid of the tabu search and greedy insertion algorithm (TSGI) can produce efficient solutions with reasonable amount of computational time.