Browsing by Author "Van Niekerk, D. J."
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- ItemExtending the BASE architecture for complex and reconfigurable cyber-physical systems using Holonic principles.(Stellenbosch : Stellenbosch University, 2021-12) Van Niekerk, D. J.; Kruger, K.; Basson, A. H.; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.ENGLISH ABSTRACT: ndustry 4.0 (I4.0) represents the newest technological revolution aimed at optimising industries using drivers such as Cyber-Physical Systems (CPSs), the Internet of Things (IoT) and many more. In the past two decades, the holonic paradigm has become a major driver of intelligent manufacturing systems, making it ideal to advance I4.0. The objective of this thesis is to extend an existing holonic reference architecture, the Biography-Attributes-Schedule-Execution (BASE) architecture, for complex and reconfigurable CPSs. In the context of this thesis, complex and reconfigurable systems are considered to be systems that are comprised of many diverse, autonomous and interacting entities, and of which the functionality, organization or size is expected to change over time. The thesis applies the principles of holonic systems to manage complexity and enhance reconfigurability of CPS applications. The BASE architecture is extended for two reasons: to enable it to integrate many diverse entities, and to enhance its reconfigurability. With regards to research on holonic systems, this thesis aims to address two important functions for systems implemented using holonic principles, namely cooperation and cyber-physical interfacing The most important extensions made to the architecture were to enable scalability, refine the cooperation between holons, and integrate cyber-physical interfacing services as Interface Holons. These extensions include platform management components (e.g. a service directory) and standardised plugins (e.g. cyber-physical interfacing plugins). The extended architecture was implemented on an educational sheep farm, because of the many heterogeneous resources (sheep, camps, sensors, humans, etc.) on the farm that need to be integrated into a BASE architecture implemented CPS. This case study implementation had to integrate data from different sensors, provide live analysis of observed data and, when required, notify the physical world of any problems in the CPS. At the end of the implementation, an evaluation was done using the requirements of a complex, reconfigurable CPS as evaluation criteria. This evaluation involved setting up quantitative and qualitative evaluation metrics for the evaluation criteria, doing the evaluations, and discussing what the results from the different evaluations indicate about the effectiveness and efficiency of the extensions made to the BASE architecture. The extensions made to the BASE architecture were found to improve robustness and resilience. The use of Erlang was found to play a very important role in the resulting reliability. The extensions also helped to fully address the original BASE architecture’s scalability shortcomings and to increase development productivity. Lastly, the extensions show the benefits of using service orientation to enable cooperation between holons and how extracting all cyber-physical interfacing of a system into dedicated Interface Holons reduces development time, improves reusability and enhances diagnosability of interfacing problems.