Modeling And Optimal Scheduling For Aircraft Final Assembly Line Based On Petri Net

The tasks of aircraft final assembly include the docking of major components, the installation of various equipments, devices and systems in aircraft, the debugging and testing of entire aircraft. The processes of aircraft final assembly contain a large amount of operations with complex constraints. Therefore the scheduling of resources in aircraft final assembly line become difficult, and it is likely to cause the disorganized managements, the crossed assembly operations, the inefficient works and other problems. It becomes an urgent problem for Chinese aviation manufacturing enterprise to optimize the scheduling of aircraft final assembly line. This paper relies on the projects assumed by Zhejiang University, and mainly researches on the modeling and optimal scheduling methods of assembly line. First, a Timed Place Petri Net (TPPN) model for an aircraft final assembly line is constructed. Then, based on the TPPN model, some new methods have been proposed to solve the static and dynamic optimal scheduling problem of the assembly line. Finally, examples are provided to verify the accuracy and effectiveness of the simulation and optimization methods.In chapter 1, the current application of aircraft final assembly line at home and abroad is summarized and the present research on modeling and optimal scheduling methods of aircraft final assembly line is elaborated. The research background and goals are introduced and the research theme is proposed. Finally, the overall structure of this paper is provided. In chapter 2, the basic concepts of the process and the operation characteristics of aircraft final assembly line are introduced. After that, the construction method and the operating rules of TPPN model are described. In the end, a TPPN model for a final assembly line is constructed according to the layout and processes of the assembly line. In chapter 3, based on the TPPN model, a multi-objective optimization model is proposed to achieve the following goals:the shortest duration, the minimum working groups, and the highest overall efficiency of working groups. Then, Analytic Hierarchy Process (AHP) is adopted to obtain the optimal solution of static scheduling problem. Finally, examples of aircraft final assembly line are provided to verify the accuracy and effectiveness of the simulation and optimization method. In chapter 4, the constraints and optimization indexes of dynamic scheduling problems in aircraft final assembly line are introduced. Then, the rescheduling strategy based on periodic and event-driven and the scrolling windows rescheduling strategy of assembly line are elaborated. By analyzing three kinds of incidents, a dynamic scheduling method based on the priority rules is proposed. Finally, the method is validated by an example of aircraft final assembly line. In chapter 5, the functional requirements of the scheduling module are analyzed and the overall framework of scheduling module is designed. Finally, the main interfaces of the software are given. In chapter 6, summary for whole work in this paper is given and the future work is discussed.