A resource investment problem based on project splitting with time windows for aircraft moving assembly line

Abstract

The aircraft moving assembly line is considered to be a large complex project consisting of some sub-projects with corresponding jobs and each sub-project corresponds to each workstations of the assembly line. This paper presents a new extension of the project scheduling problem, Resource Investment Problem based on Project Splitting with Time Windows (RIPPS_TW), in view of the characteristics of simultaneous execution of multiple workstations based on line-side shared resources and the situation of unavailable resource periods known in advance. A new concept named project splitting is proposed to divide a project into multiple sub-projects by changing the precedence constraints of jobs during scheduling, which is beneficial for improving the scheduling efficiency of the problem. To solve RIPPS_TW, we design a new mathematical optimization model and a two-stage iterative loop algorithm in this paper. In the first stage, a heuristic algorithm is applied to get the project splitting plan, then in the second stage an improved genetic algorithm combined with branch-and-bound is used to schedule jobs affected by resource time windows. In addition, a series of computational experiments are carried out, and the effectiveness of the algorithm is verified by comparison with other literature algorithm.