Research On Key Technologies Of Reconfigurable Manufacturing System

With the intensive competition of the global economy, manufacturing environment for the enterprises is undergoing dramatic and unpredictable changes. So the manufacturing enterprises must develop a new manufacturing system that can satisfy the individual needs of the different customers by means of adjusting product structures and rapidly reconfiguring the manufacturing system. Reconfigurable manufacturing systems (RMS) are put forward in such condition. It can adapt to the changes for market demands, quickly adjust manufacturing process, function and capacity.As a new advanced manufacturing system, RMS has been increasingly paid attention to, and has been carried out deep research in the area of theory and application. But the theories and the technologies of RMS are at an initial stage of development, the further reseach for the methods and technologies promote manufacturing systems to be reconfigurated is needed.So there are significant meanings to carry out researches on key technologies of RMS.This paper mainly includes the contents for the following aspects:(1) The developments and evolution for manufacturing systems are expounded and the differences between RMS and other two manufacturing patterns are discussed.The definition, characteristics, composition and key technologies of RMS are studied, and the current situation of research on the theories for RMS at home and abroad is introduced.The key technologies researched in this paper are proposed.(2) All kinds of modeling methods of manufacturing systems are discussed, and the analysis and comparison of them are made this paper. A modular modeling approach based Generalized Stochastic Petri nets (GSPN) is presented. The basic theory of Petri nets is described and the modeling and application of GSPN in the manufacturing systems are analysed. Based on bottom-up method, the modeling and analysis for RMS given in the example are carried out.(3) Whether the machine layout is proper or not affects the performance of RMS seriously. According to actual situation, two kinds of mathematical models for facility layout are established and with respect to the fact the facility layout problem belongs to NP compelet one, the Genetic Algorithm (GA) toolbox is used to solve the problem.Then the QUEST is introduced to simulate and optimize the optimal sequence of layout obtained through GA. (4) According to design theory of reconfigurable machine tool (RMT), the design method of mechanical modular for RMT is discussed deeply. The process characteristics of the workpiece are identified, and the processing operations are formulated, distincted and combined. The kinematics expression of basic functional modules for machine tool is established by screw theory, and then the motor function module of machine mechanical system is completed. Finally, the modular configuration of RMS is gained.(5) The important meanings of facility fault diagnosis for RMS are expounded and the methods of fault diagnosis based on knowledge are discussed. Fault diagnosis based on fuzzy Petri net and its reasoning algorithm are studied emphatically, then the example about faults of spindle for machine tool is researched and analyzed.