2.1 Key Enablers for the Application
Industrie 4.0 was first advanced as a forward-look project in the high-tech strategy of the German government. Then after, under the high demands of flexibility and responsiveness, and because of the intelligent capability of current technologies, Industrie 4.0 has further been trended as the pursuits of industrial environment. Based on the experiences of Industrie 4.0 Working Group, three key enables have been gathered for the implementation of Industrie 4.0 in companies. They are Internet of Thing (IoT), Cyber-Physical System and Smart Factory [7]. In general, these three are not independent, but overlapping with each other.
According to TECHOPEDI [9], IoT is considered as the scenario that all physical objects can be recognized and connected to surrounding objects and database. In industries, via the adopting of information communication technologies (e.g., RFID, sensors), IoT allows to embed the information of physical objects into virtual world, and in the end brings with the merging between real and virtual systems. Therefore, IoT is to somehow foundation for the construction of Cyber-Physical Systems. In other words, IoT is the technical infrastructure for the realization of Cyber-Physical Systems [10]. Based on the employment of IoT technologies, Cyber-Physical System can not only help to map physical systems to virtual world, but also apply on the back-loops from virtual digital system to the operation and controlling of physical processes. With the fusion on the integration between real and digital world [11], Cyber-Physical system helps to realize Smart Factories. Here, Smart Factory is considered as a major vision of Industrie 4.0. And according to Miragliotta, et al. [12] and Hopf, et al. [11], the main characteristics for the interpretation of ‘smart’ are:
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Integrated functions for identification, localization and diagnosis of internal parameters.
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Capability to detect on the physical data and measuring on the performance.
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Capability to process data for the determination on relevant information.
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Capability to interact with other smart objects and centralized information system.
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Standardization with uniform standards or protocols.
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Openness for accessibility.
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Multi-functionality for different applications.
Thus, via the interconnection of smart objects, Smart Factory enables companies with flexibility, efficiency and effectiveness. Besides, with the combining and interactions of these three enablers, the applications of Industrie 4.0 would be enhanced continuously. Under the scenarios of Industrie 4.0, companies are supposed to achieve the manufacture of “even one-off items” with profit [13]. The advantage of allowing “last minute changes” also enables the production of companies with more flexibility [13]. In addition, with the end-to-end transparency over the manufacturing process, Industrie 4.0 is also potential to facilitate optimized decision-making [13]. In general, there is no doubt about the possible benefits of Industrie 4.0. However, despite its attractiveness, still big challenges are existed for the realization of this strategic scenario. Further question arise on: ‘how to implement Industry 4.0’? To deal with this, a derivative question that should be clearly understood is: ‘which perspectives should be taken into account, so as to help to realize Industrie 4.0 with more detail’. Thus, in the following stages, tasks of the study will be moved from the macro understanding to the implementation aspect of the object.
2.2 Reference Architecture of Industrie 4.0
Considering as a revolution, the concept Industrie 4.0 is criticized to be “lack of knowledge of the details” [14], especially when it comes to the detail applications of this industrial strategy. With this in mind, and in order to support to execute Industrie 4.0 in companies, a reference architecture has been established as in Figure 1.
As illustrated in Figure 1, four major perspectives have been emphasized for the execution of Industrie 4.0. They are issues related to the manufacturing process, devices, software and engineering. With the employment of IoT technologies, all possible processing and transport functions of the manufacturing process would be mapped and recorded as in the virtual information system with real time. Moreover, devices within the manufacturing system would be considered as ‘Things’ or ‘objects’. These include (smart) automation devices, field devices, fieldbuses, programmable logic controllers, operating devices, mobile devices, servers, workstations, web access devices and so on. Relative embedded technologies will also be used to merge these physical devices with virtual systems. And the conditions of the physical devices would be recorded automatically to the information system. The software perspective emphasizes on the software realization for the interfaces and integration among items from the physical-, cyber- and automation-levels. Possible existing software includes business management software, production management software, control and regulation software and so on. And the application of these software not only brings with interactions among “Things”, but also enables users to achieve planning, organizing, coordination and controlling of “Things”. The perspective of engineering in the manufacturing system is more related on the Production Lifecycle Management. With the using of data derived from the manufacturing process, analyze to plan the necessary resources in terms of both machinery and human resource. And the tasks of resource allocation include issues related to production design and development, production planning, production engineering, production, and services.
In general, these four perspectives work together as in a reference architecture, which helps to detail the application of Industrie 4.0 into the implementation level. And the former two focus on the mapping and merging between real and virtual systems, while the late highlight on the fusion and application based on the integration of these two systems. Thus, considering the usage of IoT technologies as the foundation, further challenge for the implementation of Industrie 4.0 lies on the issue “how to realize fusion for the autonomous decision”. Here, the application of Cyber-Physical Systems was suggested as one of the most efficient channels [3].
2.3 Structure of Cyber-Physical System
Cyber-Physical Production System refers to “physical and virtual, local and global, horizontally and vertically networked systems, dynamic system boundaries, partial or complete autonomy, active real-time control, cooperation and comprehensive cooperation between human and system” [14]. It comprises smart machines, warehousing systems and production facilities that have been developed digitally and feature end-to-end Information Communication Technology-based integration, from inbound logistics to production, marketing, outbound logistics and service. Based on the Final report of the Industrie 4.0 Working Group [7], general structure of Cyber-Physical System has been gathered as in Figure 2.
As illustrated in Figure 2, the basic logic for the establishment of Cyber-Physical System is the connecting of real and virtual production. It is developed based on the establishment of virtual system with real time information (shown as in the left side of Figure 2), and goes beyond the scope of IoT. In others words, Cyber-Physical System is the sublimation for the application of IoT. General focus for the usage of Cyber-Physical System lies not only on the gathering of real time data from the physical environment to the digital system, but more on the structure analysis of data sources for (partly) autonomous and self-organized processes. Thus, the back-loops of virtual information system to the operation and controlling of physical processes is considered as the spirit of Cyber-Physical Systems. And with the establishment of Cyber-Physical Systems, Smart Factory is enabled to be possible in companies. Here, Smart Factory “constitutes - key features of Industrie 4.0” [7]. And under the Smart Factories, “in addition to condition monitoring and fault diagnosis, components and systems are able to gain self-awareness and self-productiveness, which will provide management with more insight on the status of the factory. Furthermore, peer-to-peer comparison and fusion of health information from various components provides a precise health prediction in component and system levels and force factory management to trigger required maintenance at the best possible time to reach just-in time maintenance and gain near zero downtime” [15]. Taken together, it is of great importance for the realization of Industrie 4.0 in companies. And in order to provide an in-depth insight on the possible solutions on the application of Industrie 4.0, experiences with applied cases will be worked out as in the following stages.