Department of Mechanical and Mechatronic Engineering

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Browsing Department of Mechanical and Mechatronic Engineering by browse.metadata.advisor "Basson, AH"

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    An Architecture for the Integration of Human Workers into an Industry 4.0 Manufacturing Environment.
    (Stellenbosch : Stellenbosch University, 2021-04) Sparrow, DE; Kruger, K; Basson, AH; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH SUMMARY: With the rise of Industry 4.0 and the development in technologies that contribute to this revolution in manufacturing, research has focused mainly on the machines and automated digital systems contributing to the manufacturing environment. Humans are still critical to manufacturing; offering unmatched ingenuity, robustness, and flexibility despite their apparent disadvantages in strength or precision. Many successful manufacturing firms still include humans in their manufacturing processes for these reasons, and it is critical that the integration of humans in an I4.0 manufacturing environment is given research attention. This dissertation first explores the requirements for the integration of human workers into an I4.0 environment. It was determined that the largest problem with human integration exists with data related to the human being digitised, managed, and communicated with other entities in processes that are identified as Administrative Logistics. It is identified that an administration shell similar to the RAMI4.0 administration shell concept is required to manage these Administrative Logistics on behalf of the human, and that a holonic systems approach is beneficial. The dissertation then proposes the concept of a Human Resource Holon Administration shell (HRH-AS). An architecture to implement such an administration shell is then developed, here named the BASE architecture. This administration shell facilitates the interfacing, data processing, and connectivity to other I4.0 components on behalf of the human, to aid in their integration to the digital factory environment around them. The BASE architecture addresses three identified responsibilities of such an administration shell, namely interfacing, digital data management, and delegation to other I4.0 components. BASE stands for Biography, Attributes, Schedule, and Execution, and is a time-based separation of concerns for key augmentations provided to the human worker. The BASE architecture separates value-adding and decision-making plugin components, which are specific to an application, from the core components, which are generic to any application. The BASE architecture led to the development of the 3SAL activity structure to facilitate the communication and management of industrial activities in a digital environment. With the help of an industry partner, two case studies were developed to evaluate an implementation of the BASE architecture. The company is an aerospace composites manufacturer and was chosen for the labour-intensive requirements of the composites industry. The case studies aimed to evaluate the architecture against the three identified administration shell responsibilities and determine if the human workers are elevated to resource holon status. The first case study aimed to show how BASE facilitates interfacing with humans in an I4.0 environment and also acted as a technology demonstrator for the second case study. The second case study evaluated the effect BASE had on the Administrative Logistics involved in the business processes workers were involved in. Together these case studies fully evaluate BASE’s ability to facilitate the integration of humans into an I4.0 manufacturing environment through identified responsibilities of the administration shell. The evaluation found that the BASE HRH-AS improves the effectiveness of Administrative Logistics of business processes the human workers were involved with, as well as opened new opportunities for decision making on the shop floor previously not possible. Value-adding, by means of the plug-in components of a BASE administration shell, has also been proven by the ability to do automated schedule management, automatic calculation of standard work and improved traceability using the 3SAL activity structure.
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    ARTI-based holonic control implementation for a manufacturing system using the base architecture
    (Stellenbosch : Stellenbosch University, 2022-04) Wasserman, Alexander; Kruger, K; Basson, AH; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH SUMMARY: With industry’s drive to adopt Industry 4.0 technologies, and their enabling technologies, in manufacturing processes, intelligent automated manufacturing has become largely sought after. With defining features such as robustness, reconfigurability and scalability, the Holonic Manufacturing Execution System (HMES) approach shows great potential to satisfy Industry 4.0 requirements. Implementations of these systems have been historically known to require great development effort and time. These implementations are however being aided by the development of holonic reference architectures, such as the Product-Resource-Order-Staff-Architecture (PROSA) and its recent revision the Activity-Resource- Type-Instance (ARTI) architecture. This thesis presents an ARTI-based HMES implementation. The implementation of this system is aided through the use of the Biography-Attributes-Schedule-Execution (BASE) architecture for digital administration shells. The BASE architecture was initially developed as a framework for the development of a digital administration shell for a human worker, in order to elevate the human worker to the level of a Cyber-Physical System. It was however proposed that the BASE architecture also had the potential to be used in a manufacturing context. The possibility of implementing the ARTI-based HMES using the BASE architecture for the respective ARTI holons is confirmed through a mapping of the ARTI architecture to the BASE architecture. The HMES is implemented on a Fischertechnik Industry 4.0 Training Factory, a small-scale manufacturing system, as a case study system. The complexity of the case study, which comprises several interacting subsystems, provides a good basis for evaluating the ARTI and BASE architectures for HMES development. The thesis concludes that the ARTI architecture provides a well-defined structure for the conceptual design of HMESs, while the BASE architecture effectively supports the implementation of ARTI-based HMESs with little additional development required.
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    A design framework for aggregation in a system of digital twins
    (Stellenbosch : Stellenbosch University, 2022-04) Human, Carlo; Basson, AH; Kruger, K; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH SUMMARY: The digital twin (DT) concept has become a popular means of capturing and utilising data related to physical systems and has been applied in many domains. The data provided within DTs allow for the integration of services and models to improve understanding and decision-making related to the physical system. Through aggregation, multiple DTs can be combined to represent larger, more complex system, while maintaining the separation of concerns. The design framework presented in this dissertation aims to enable systematic, effective decisions when designing a system of DTs to represent a complex physical system. In particular, this framework adopts hierarchical aggregation as one of its primary enablers and it considers the use of a services network, such as a service-oriented architecture, as well. The design framework is intended to be broadly applicable, by remaining vendor-neutral, and it enables traceability of design choices. The approach starts with an analysis of physical system complexity to identify key needs related to managing complexity. A suitable requirements classification is then introduced to help translate the needs into requirements that the system of DTs should satisfy. Hierarchical aggregation is also introduced as a primary architectural approach to manage complexity. Hierarchical aggregation allows for the separation of concerns, computational load distribution, incremental development and modular software design. The design framework is arranged in six steps: 1) needs and constraints analysis, 2) physical system decomposition, 3) services allocation, 4) performance and quality considerations, 5) implementation considerations and 6) verification and validation. The dissertation then introduces a general reference architecture that combines a system of DTs (which follows hierarchical aggregation principles) with a services network to allow for reliable and adaptable service provisioning. The design framework is then discussed in the context of the general reference architecture. The design steps of the design framework are then moulded into six design patterns, which simplify the design process by focussing of key quality attributes. The quality attributes considered for the respective design patterns are performance efficiency, reliability, maintainability, compatibility, portability and security. The use of the design framework and design patterns are then demonstrated and validated through three case studies, two high-level case studies and one detailed case study. The high-level case studies consider a water distribution system and a smart city, respectively. The detailed case study considers a heliostat field. The dissertation concludes that the design framework, as well as the design patterns, enable a systematic approach to designing a system of DTs. The design framework can also be applied to numerous and varying domains, such as the case studies considered.
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    Development of a clinical pathway digital twin.
    (Stellenbosch : Stellenbosch University, 2024-02) Erwee, H; Basson, AH; Kruger, K; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: The healthcare industry faces significant challenges due to the rapid technological advancements of Industry 4.0 as large volumes of data gets generated within healthcare facilities daily, which contains complex data relationships and a high variety of data. This surge of data, coupled with the complex nature of healthcare environments, is making it hard for healthcare professionals to effectively interpret and utilise healthcare data. This research aims to address this challenge by investigating the potential integration of digital twin technology into the healthcare domain, specifically within a clinical pathway context. This study, therefore, evaluates the concept of a Clinical Pathway Digital Twin (CPDT) as an information management tool for enhanced healthcare within clinical pathways. A requirement analysis was conducted to derive a set of fundamental requirements that a typical CPDT should meet. Mediclinic SA played an instrumental role during this phase by facilitating on-site observations at their hip and knee replacement clinical pathway at the Mediclinic Durbanville Hospital. Insights from these observations, combined with insights from literature, led to the identification of the following key needs within the clinical pathway context: real-time monitoring, standardised processes, regular and automatic data analysis, and effective human integration. In the research presented here, the CPDT requirements specifically focussed on enabling regular and automated data analysis within the clinical pathway. A proof-of-concept CPDT was developed and evaluated using a case study-based approach. The development of the CPDT followed a holonic system design process, using the Activity-Resource-Type-Instance (ARTI) holonic architecture. The Biography-Attributes-Schedule-Execution (BASE) platform was used to implement the holons. The CPDT is the first application of the BASE platform to explore its use for managing large volumes of data. Furthermore, the CPDT utilised an external data repository for the long-term storage of clinical pathway data and interfaced with external software to perform advanced analyses. In the case study, experiments were conducted to evaluate the CPDT's performance. These experiments demonstrated the CPDT’s ability to ingest data from data repositories, perform automated statistical analyses, and generate on-demand reports, thereby reducing manual tasks for healthcare professionals. The CPDT's interfacing with external analysis software for machine learning predictions of future activities demonstrated how healthcare professionals can derive valuable insights from the CPDT to inform decision-making within the clinical pathway. The CPDT successfully fulfilled all its functional requirements. Its modular ARTIbased holonic architecture allows easy adjustment of holon capabilities through modification of BASE plugins. The decentralised approach to clinical pathway data management demonstrated high data integrity and flexibility. The practical value of the CPDT is evident from the case study, with potential to improve clinical pathway efficiency, improve patient outcomes, and reduce healthcare costs. While the case study focused on a hip and knee replacement clinical pathway context, the results show potential for application across various clinical pathways, warranting further investigation and research.
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    A digital twin architecture for a water distribution system.
    (Stellenbosch : Stellenbosch University, 2022-11) Goosen, Ockert Johann; Basson, AH; Kruger, K; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: The incorporation of Industry 4.0 technologies in the water sector is providing water utilities with the necessary tools and insights to combat WDS-related challenges such as water management (e.g. leak detection) and future planning to meet increasing demand. A key enabler in Industry 4.0-related technologies is the concept of a digital twin. Digital twins may provide water utilities with improved insight into their WDSs and enable services that can facilitate data-driven decision-making. This thesis proposes and evaluates a digital twin architecture for a water distribution system (WDS) based on the Six Layer Architecture for Digital Twins with Aggregation (SLADTA). The digital twin architecture aims to facilitate the unique challenges and characteristics present in WDSs. Aspects include the complexity of heterogenous monitoring devices installed on WDSs and potential physical and management-related reconfigurations of WDSs. This thesis evaluates whether digital twin architecture designed according to SLADTA can overcome these challenges and provide the framework to develop a WDS digital twin with the desired characteristics. Several modifications were made in the process of mapping SLADTA (previously implemented in the manufacturing and renewable energy infrastructure domains) to a WDS-focused digital twin architecture. The thesis evaluates the WDS digital twin architecture using two case studies, each with several experiments, to determine whether the proposed architecture can meet the determined WDS digital twin requirements. The case studies also explore how the aggregation philosophy, inherent in SLADTA, can be implemented on WDSs. The first case study implements the WDS digital twin architecture for a laboratory scale WDS. The laboratory scale WDS replicates the real-world complexity of heterogeneous data sources by containing a variety of monitoring devices commonly used in industry. This case study also shows the ability of the WDS digital twin to integrate services, such as anomaly detection. In the second case study, a large-scale, simulated WDS is used to evaluate the WDS digital twin architecture’s ability to accommodate reconfiguration. WDS-related reconfiguration includes changes to a WDS’s monitoring capacity, changes to a WDS management organisations’ boundaries or zone and adding new WDS infrastructure to an existing digital twin. Additionally, the WDS digital twin architecture’s ability to incorporate WDS domain services, such as modelling of the hydraulic behaviour in a WDS, is investigated. The performance of the WDS digital twin architecture presented in this thesis is, therefore, demonstrated in a real-world, but laboratory-scale, case study and in a complex, but simulated, case study. The case study implementations show that the proposed architecture is capable of meeting the functional requirements that were derived from WDS operator needs.
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    A digital twin system for the integration of railway infrastructure data.
    (Stellenbosch : Stellenbosch University, 2022-11) Doubell, Gerhardus Christiaan; Kruger, K; Basson, AH; Conradie, PDF; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: The integration of data within large complex systems, such as railway infrastructure, forms a key component of enabling data-led decision making. Data can exist in numerous different data silos, provided by different data sources, with different interfaces and encapsulated data properties. The Passenger Rail Agency of South Africa (PRASA) currently faces this challenge. Research on digital twins (DTs) highlight the integration of data as one of the key advantages of DTs. However, very little research has been published on the implementation of DTs within railway infrastructure and, in particular, for the integration of data. Considering the above, this thesis presents the development of a DT system technology demonstrator for the integration of data for PRASA’s railway infrastructure. This technology demonstrator is evaluated based on a case study implementation for PRASA maintenance management in the Western Cape province. The DT system architecture utilises a layer with various “wrapper” components to provide specific interfaces to each of the data sources to be included in the system. In addition to the wrapper layer, the DT system architecture utilises a DT aggregation hierarchy to store data that represents physical reality, where each DT can also provide services that rely purely in the DT's scope of reality. The DT hierarchy is complemented with a services network to provide the required services that, as dictated by its purpose, integrates information from various DTs and, potentially, external sources. The DT system architecture is intended to be vendor-neutral and can therefore be broadly implemented. The developed DT system promises to be a valuable tool for maintenance management, by providing a holistic view of the railway infrastructure. The view can be reconfigured to adapt to changing infrastructure, data sources and user needs. Having been tested with diverse data sources and interfaces, complex relationships between infrastructural elements, and changing requirements and infrastructure, the DT system technology demonstrator can be considered suitable for PRASA’s railway infrastructure network, but also for other contexts where a similar environment (with regards to data sources and interfaces) is encountered. The integration of data through the DT system provides a means through which the number of data sources that need to be consulted for decision making, can be reduced. At the same time, the DT system provides a platform from which additional services can be offered, both now and in the future.
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    A holonic human cyber-physical system in healthcare
    (Stellenbosch : Stellenbosch University, 2022-11) Defty, TW; Kruger, K; Basson, AH; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: The fourth industrial revolution (I4.0) aims to enhance operational performance and promote interconnectivity between system components. Labour-intensive industries which are reliant on humans to perform tasks along with automation and integrated equipment are typically classified as Human Cyber-Physical Systems (HCPSs). Many I4.0 developments within HCPSs lack the appropriate consideration and integration of humans, resulting in performance inefficiencies, quality concerns, and under-utilisation. Healthcare is one such industry, with challenges due to a lack of integration developments which are exacerbated by limited resources and high patient volumes. The objective of this thesis is the development of a holonic HCPS for healthcare. These holonic HCPS developments address challenges in healthcare through the application of Human-System Integration (HSI) principles and requirements. HSI aims to enhance human intelligence and cooperation within digitised environments. HCPSs within this study are defined by human, physical and digital components that interact in a complex manner to achieve overall system goals. An ambulatory clinic case study was selected to study the complex interactions between system components and actors. This thesis presents a Representation-Communication-Interfacing (RCI) framework to better define HSI and guide the development and evaluation of the HSI maturity in HCPSs. A holonic system approach is selected, using the RCI framework, to improve the maturity of HSI developments in healthcare. This thesis presents a structured design process for holonic systems using the Activity-Resource-Type-Instance (ARTI) architecture and the Biography-Attribute-Schedule-Execution (BASE) architecture. The design process is presented in response to a lack of available implementation details expressed in reviewed holonic applications. The developed holonic HCPS is evaluated experimentally, to showcase how the system meets the requirements and enhances the HSI maturity of the ambulatory case study. The evaluation shows that the holonic HCPS effectively integrates humans, resulting in improved operational efficiencies and lower workloads experienced by humans. The RCI framework offers valuable guidance for elevating the human component to the cyber layer, improving the autonomy and cooperability of humans in the system and easing the reconfigurability of the system. The holonic design process guides the system development by standardising the partitioning of system components and interactions into distinct holons. Furthermore, this design process reduces the development complexity and time. The holonic HCPS demonstrates how HSI developments can improve clinic workflow efficiencies, aid decision-making, improve the traceability of activities and reduce the workload for healthcare practitioners.
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    Human-system integration in emergency room environments
    (Stellenbosch : Stellenbosch University, 2023-11) Nicholls, KM; Basson, AH; Kruger, K; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: This research develops the digital component of an emergency centre human cyber-physical system (EC-HCPS) to facilitate information management. The patient treatment pathway through a hospital emergency centre is analysed to improve human-system integration (HSI). The Representation-Communication Interfacing (RCI) framework is used throughout the system design and evaluation process to achieve HSI. The Activity-Resource-Type-Instance (ARTI) architecture is used to develop the system architecture which consists of interacting activity and resource holons. The EC-HCPS is implemented using the Biography-Attributes-Schedule-Execution (BASE) software platform. The ARTI architecture design was mapped to the BASE software platform using the holonic system design process and user interfaces were developed using the web-based server, Svelte Kit. The functional and non-functional system requirements and the degree to which HSI was improved were tested by conducting an evaluation experiment at the Constantiaberg Mediclinic Emergency Centre. Ethics clearance was obtained from the Research Ethics Committee for Social, Behavioural and Education research at Stellenbosch University in 2022 to conduct the case study. The evaluation methods included a system comparison experiment, a user survey and a controlled simulation. The results show that the EC-HCPS satisfies the functional requirements by performing multimodal data acquisition, recording, storing and analysing data, as well as enabling information sharing. Several non-functional requirements were tested and satisfied, such as efficiency; however, some software characteristics do require further work. The evaluation of the EC-HCPS shows that the system improves HSI by adding maturity to each dimension of the RCI framework. The representation of various resources in a hospital EC enables both personal and state data to be recorded, stored and analysed. The system reduces the cognitive load on medical staff through its reminders and messaging functionality and through proactive information sharing. The interfacing dimension achieves information filtering and interface personalisation. This helps to make the workflow of staff easier and more efficient. The intersection of all three RCI dimensions enables the system to assist with error reduction and aid the decision making of the user. The EC-HCPS provides a human-centric approach to manage information in a hospital EC. This research did not consider the challenges of system deployment – an area of future research. Prior to this, increased system testing is required to better evaluate the quality of the system software.
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    Integration of digital twins and virtual reality for data visualisation.
    (Stellenbosch : Stellenbosch University, 2022-11) Da Silva, GS; Kruger, K; Basson, AH; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: This thesis considers an integration of digital twins (DTs) and virtual reality (VR) for enhancing the data driven decision-making process. An integrated DT and VR system is designed according to an available complex DT system design framework. The Six Layer Architecture for Digital Twins with Aggregation (SLADTA) is used for the internal architecture of the DTs in the system. A custom developed VR application is used to visualise the information using VR equipment. The Facilities Management (FM) Division at Stellenbosch University serves as the chosen case study context for the evaluation. The energy usage information for various facilities of FM is visualised in VR. The DT method of transferring information to VR is compared to a method that does not make use of DTs. Three experiments are used to evaluate the two implementation methods to allow for an adequate comparison of the two methods. The experiments focus on, respectively, latency, computer resource utilisation (in terms of RAM and CPU usage), and reconfigurability when a new feature is to be added to the system. The experiment results indicate that the DT method has lower latencies, the two methods have similar computational resource needs, and the non-DT method is more reconfigurable than the DT method. However, the DT method offers other advantages such as allowing for two VR experiences to visualise the same information, or allowing for a different visualisation tool, other than VR, to be integrated seamlessly into the system. The DT method also allows for a distributed operation functionality that reduces the computational load required from a single hardware device. The Non-DT method does not offer such advantages. The thesis concludes that the integration of DTs and VR for data visualisation is possible and is favourable for a system that will not only use VR as a data visualisation means.
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    Towards a protocol for evaluating unrestrained torso neck braces.
    (Stellenbosch : Stellenbosch University, 2024-02) De Jongh, Cornelis Uys; Basson, AH; Knox, EH; Stellenbosch University. Faculty of Engineering. Dept. of Mechanical and Mechatronic Engineering.
    ENGLISH ABSTRACT: The relatively recent introduction of neck braces for the unrestrained, helmeted rider in extreme activities has necessitated an understanding of the underlying biomechanics resulting from headfirst impacts while wearing these devices. Currently, no established or commonly accepted pathway exists to independently evaluate, and subsequently approve, these devices. The aim of this dissertation is to propose key elements of a protocol for the evaluation of unrestrained torso neck braces resulting in a reliable determination of intervention efficacy. Specific objectives include identifying the relevant neck injury mechanisms from literature, recreating those mechanisms in testing and computational simulations, and identifying applicable neck measures, criteria, and injury risks to evaluate. A further objective is to critically evaluate the proposed methods, measures, and correlates through a case study, using a neck brace. The dissertation presents two tests and a computational model to evaluate neck brace efficacy. The first test, an inverted pendulum test, is proposed to evaluate compression flexion, tension flexion, and tension extension using an HIII ATD neck, and a motorcycle-specific ATD neck (MATD). The second test addresses the most important neck injury mechanism related to motorcycle accidents, compression flexion. This test distinguishes itself from the first test in that the degree of anterior head impact eccentricity is reduced and the baseline impact energy results in neck axial forces approaching injury assessment reference values (IARV). Using a current neck brace as a case study, the proposed tests bring to light important observations in evaluating a neck brace for each mechanism investigated. The ability of the tests to underscore the potential benefits and adverse effects of a neck brace is investigated through the evaluation of the appropriate upper and lower neck response measures. Lastly, a solid-body computational model is proposed to simulate neck response with and without a neck brace for a variety of head impact conditions. These simulations may be used to augment tests that use an HIII ATD neck, considering the challenges associated with using these instruments. The computational model can highlight aspects such as changing neck brace efficacy for varying impact configurations. The proposed method identifies a set of novel methods to visualize and interpret computed neck response data with and without a neck brace when large datasets are created. This work contributes towards the establishment of a novel protocol by which to gauge neck brace performance using applicable biomechanical considerations through testing and computational biomechanics. The chosen loading modalities, neck injury mechanisms, resulting neck response measures, injury criteria, and injury risks evaluated are relevant to the proposed analyses and create a basis for the establishment of a formal testing protocol. A protocol whereby unrestrained torso neck braces can effectively and critically be evaluated will allow product designers to be creative in their endeavors while conforming to a set of safety measures that effectively address important biomechanical considerations required for these device types. The combination of testing and real-world impact simulations enables the efficacy prediction of neck braces to converge with real-world effectiveness.