Research On System Modeling And Key Technology Of Intelligent Assembly System For Mechanical Products Based On Manufacturing Internet Of Things

With the intensification of global market competition, manufacturing industry as the pillar industry and the core power of national economic development will face an unprecedented severe challenge. In order to adapt to the complex market environment, Internet of Things (IOT) enabled intelligent manufacturing strategy will be a new developing directions of manufacturing industry. Mechanical manufacturing industry is a basic manufacturing industry which provides technology and equipment for national economic development. Thus, it can be seen the mechanical manufacturing industry has the pivotal status and the function in the national economy as well as in the local economy development. In the manufacturing process, assembly is the final phase with some peculiar characteristics (e.g. complicated operation, management and many others), so it is urgently needed to enhance intellectualized degree of the assembly system by developing and applying IOT technology. Therefore, this paper takes the assembly system for mechanical products as the research object. In this paper, the IOT-based intelligent assembly system modeling and key technology for mechanical products are mainly discussed to enhance the transparency and intelligence of the assembly process of mechanical products. The proposed method aims to have an important reference value for applying IOT to build an intelligent assembly system for mechanical products.Firstly, according to the review of the research situation of intelligent manufacturing, this study not only analyses the causes, contents, basic goals and the roles of the IOT in intelligent manufacturing strategy, but also points out the problems of applying IOT manufacturing. Based on the above, the research sources, research contents and research framework are introduced in this paper immediately.Then, according to the analysis of the IOT contents and characteristics, this study proposes the IOT-enabled intelligent assembly system for mechanical products (MIOT-IASMP). The characteristic, content, framework, cyber-physical environment and topology of MIOT-IASMP are then presented. Key technologies under this framework, including assembly resources modeling and configuration, information interaction technology, multi-source data perception and integration, intelligent assembly agent and dynamic self-adaptive optimization, are described.Next, focusing on the core problems of this paper, the assembly resources modeling and configuration, multi-source perception and data integration, intelligent assembly agent and dynamic optimization are studied respectively. The contents are as follows:According to the analysis of the IOT-enabled assembly system, a kind of assembly resource classification for mechanical products under IOT environment is put forward. On this basis, meta-ontology modeling, semantic modeling theories and other methods are used to build the hierarchical model, overall model, semantic model, data model, mapping model and configuration model of the IOT based assembly resource. These proposed models can not only well realize the expression, understanding, reasoning, retrieval and sharing of the IOT based assembly resource, but also can provide a standard structure and derived-object for supporting the operation of the intelligent assembly system.In accordance with the data perception, data integration and data interaction issues faced by the IOT-enabled assembly system for mechanical products, this study designs the data structure and encoding structure for IOT based assembly resource. The multi-source data perception and integration framework, which is based on advanced techniques such as information and communication technology, sensor network, and radio-frequency identification, is then presented. On this basis, a real-time data interaction framework of the IOT based assembly resource is put forward to support the system operation, decision and optimization.To achieve the changes of system control mode from centralized control to distributed control, here the object-oriented method is used to abstract assembly system to some collections of object, which consists of some assembly agents. Then, according to the analysis of the characteristics of IOT-based assembly system, an IOT-enabled intelligent assembly agent is proposed. The content and characteristic of an intelligent assembly agent are then extracted. On this basis, the structure, framework, operation mechanism and perception-based servo control chart of intelligent assembly agent are introduced. Finally, the operation and implementation methods of the perception-based servo control chart are researched in this paper.According to the architecture and functional features of assembly system, this study puts forward a multi-layered dynamic optimization system for the existed uncertainty of the assembly process. Then, the dynamic optimization factors for assembly process are extracted. The IOT-entropy enabled calculating model of the dynamic optimization index is also proposed. Based on the above, this paper presents a real-time data based dynamic optimization model of the assembly process for mechanical products. According to the dynamic optimization model’s real-time analysis and optimization, the assembly system stability can be well improved.Finally, timed-based colored object-oriented petri net (TCOPN) method and VisObjNet simulation technology are used to achieve system abstracting, modeling and simulation. A prototype system is developed to prove the effectiveness and feasibility of this approach.