A Maclaurin-series expansion approach to coupled queues with phase-type distributed service times

International audienc

The co-incident flow of work pieces and cutting tools in a restricted category of flexible machining cells

The work reported in this thesis describes research carried out into the detailed design and operation of Flexible Machining Cells (FMC) incorporating automated work and tool flow, dual flow. Three modes of cell management are considered for dual flow cells, where the author examines both their operational and economic performance. A framework is defined for investigating these dual flow cells, and a structured approach providing a novel and detailed modelling capability is described. The question of how this approach compares to single flow modelling and the additional or alternative requirements for dual flow modelling is examined via the following key areas; the specification of material handling requirements, tool transportation and issue and finally, the control required to examine the interaction between the two flows operating concurrently. The framework is tested for its industrial applicability via an industrial case study. A major aim of this study is to examine the view that a hybrid cell management strategy, competitive management, could outperform the other strategies examined. The aim of this methodology is to provide a solution for the control of FMCs. Emphasis is placed on the ease of control and how the loading and control rules selection can maximise economic enhancement of a cells performance

"Production Ergonomics

"Production ergonomics – the science and practice of designing industrial workplaces to optimize human well-being and system performance – is a complex challenge for a designer. Humans are a valuable and flexible resource in any system of creation, and as long as they stay healthy, alert and motivated, they perform well and also become more competent over time, which increases their value as a resource. However, if a system designer is not mindful or aware of the many threats to health and system performance that may emerge, the end result may include inefficiency, productivity losses, low working morale, injuries and sick-leave. To help budding system designers and production engineers tackle these design challenges holistically, this book offers a multi-faceted orientation in the prerequisites for healthy and effective human work. We will cover physical, cognitive and organizational aspects of ergonomics, and provide both the individual human perspective and that of groups and populations, ending up with a look at global challenges that require workplaces to become more socially and economically sustainable. This book is written to give you a warm welcome to the subject, and to provide a solid foundation for improving industrial workplaces to attract and retain healthy and productive staff in the long run.

Materials Handling in Production Systems: Design and Performance of Kit Preparation

This thesis focuses on processes for kit preparation, which are applied with the materials supply principle of kitting in production systems for mixed-model assembly. With kitting, assembly processes are supplied with portions of pre-sorted components, and each portion makes up a kit that holds the components needed for one assembly object at one or several assembly processes. When kitting is applied, picking activities, which are otherwise performed at assembly processes, are instead carried out in a process for kit preparation. Kit preparation involves collecting components designated for a particular assembly object into a single unit load that is delivered to assembly.Kitting is widely seen as beneficial for quality and flexibility in assembly processes when there are a large variety of components. Performance effects in assembly processes normally associated with kitting largely depend on the performance of kit preparation. Previous research indicates that a picking system’s design greatly impacts its performance. While research that has dealt with kit preparation points out several design aspects that can affect its performance, the available knowledge is far from exhaustive. The purpose of this thesis is to contribute to the knowledge of how kit preparation design aspects govern kit preparation performance.Case research, experiments, and modelling have been used to study how flexibility, kit quality and man-hour efficiency are affected by kit preparation design aspects related to work organisation, layout, policies, packaging, equipment, picking information, automation and control. Two case research studies respectively address kit preparation flexibility and kit quality, identifying how kit preparation design aspects can be configured to support these two performance areas. Two experiments focus on how picking information systems and confirmation methods affect kit preparation man-hour efficiency. One modelling study focuses on how collaborative robots can support man-hour efficient kit preparation. Through involvement in three research projects and an extensive review of the literature, this research has been guided by the needs of industry and by previously established knowledge.This thesis contributes to theory and to practice in the form of knowledge about relationships between kit preparation design aspects and the performance areas flexibility, kit quality and manhour efficiency. The theoretical contribution consists of building upon and underpinning the limitedknowledge about the topic that has been previously available, while also adding new knowledge. This includes, for example, glasses with integrated computer displays, RFID-scanning wristbands, and collaborative robots, and how they are linked to kit preparation performance. The practical contribution consists of concise yet holistic descriptions of relationships between kit preparation design and performance, which industry can readily adopt with some consideration to the situation’s characteristics

Design of tool management systems for flexible manufacturing systems

The objective of this thesis is to study the design and analysis of tool management system in the automated manufacturing systems. The thesis is focused on two main areas, namely design and experiment. In the first part of the thesis, the design facility created has been reported. The model has been designed using a hybrid approach in which the power of both algorithmic and knowledge based approaches is utilised. Model permits detail, more accurate and complete solutions for the management of tools in a generic manufacturing system. In the second part of the thesis, to add more understanding to the tool management problems, the interactions of the major tool management design parameters have been investigated using a well known design technique, the Taguchi method. For this purpose, a large number of design experiments have been configured where some have been suggested by the Taguchi method and some have been created by the author to add more confidence, using a large body of real industrial data. The experiments results give deeper understanding of TMS problems and allow design guide-lines to be drawn for the designers. The design approach and the experiments have been proven to be an accurate and valid tool for the design of tool management systems for automated manufacturing systems. This is indicated in the conclusion of the thesis

Effects of the Human Presence among Robots in the ARIAC 2023 Industrial Automation Competition

Acknowledgements The authors thank all NIST employees and interns involved in running ARIAC 2023 and, most importantly, to the teams that took part in the competition.Peer reviewe