The primary objectives in this research are to develop computer-aided design (CAD) tools for Design for Manufacturability (DFM) solutions that enable designers to conduct more rapid and more accurate systematic variation analysis, with different design enhancement techniques. Four main CAD tools are developed throughout my thesis. The first CAD tool facilitates a quantitative study of the impact of systematic variations for different circuits' electrical and geometrical behavior. This is accomplished by automatically performing an extensive analysis of different process variations (lithography and stress) and their dependency on the design context. Such a tool helps to explore and evaluate the systematic variation impact on any type of design. Secondly, solutions in the industry focus on the "design and then fix philosophy", or "fix during design philosophy", whereas the next CAD tool involves the "fix before design philosophy". Here, the standard cell library is characterized in different design contexts, different resolution enhancement techniques, and different process conditions, generating a fully DFM-aware standard cell library using a newly developed methodology that dramatically reduce the required number of silicon simulations. Several experiments are conducted on 65nm and 45nm designs, and demonstrate more robust and manufacturable designs that can be implemented by using the DFM-aware standard cell library. Thirdly, a novel electrical-aware hotspot detection solution is developed by using a device parameter-based matching technique since the state-of-the-art hotspot detection solutions are all geometrical based. This CAD tool proposes a new philosophy by detecting yield limiters, also known as hotspots, through the model parameters of the device, presented in the SPICE netlist. This novel hotspot detection methodology is tested and delivers extraordinary fast and accurate results. Finally, the existing DFM solutions, mainly address the digital designs. Process variations play an increasingly important role in the success of analog circuits. Knowledge of the parameter variances and their contribution patterns is crucial for a successful design process. This information is valuable to find solutions for many problems in design, design automation, testing, and fault tolerance. The fourth CAD solution, proposed in this thesis, introduces a variability-aware DFM solution that detects, analyze, and automatically correct hotspots for analog circuits.

The primary objectives in this research are to develop computer-aided design (CAD) tools for Design for Manufacturability (DFM) solutions that enable designers to conduct more rapid and more accurate systematic variation analysis, with different design enhancement techniques. Four main CAD tools are developed throughout my thesis. The first CAD tool facilitates a quantitative study of the impact of systematic variations for different circuits' electrical and geometrical behavior. This is accomplished by automatically performing an extensive analysis of different process variations (lithography and stress) and their dependency on the design context. Such a tool helps to explore and evaluate the systematic variation impact on any type of design. Secondly, solutions in the industry focus on the "design and then fix philosophy", or "fix during design philosophy", whereas the next CAD tool involves the "fix before design philosophy". Here, the standard cell library is characterized in different design contexts, different resolution enhancement techniques, and different process conditions, generating a fully DFM-aware standard cell library using a newly developed methodology that dramatically reduce the required number of silicon simulations. Several experiments are conducted on 65nm and 45nm designs, and demonstrate more robust and manufacturable designs that can be implemented by using the DFM-aware standard cell library. Thirdly, a novel electrical-aware hotspot detection solution is developed by using a device parameter-based matching technique since the state-of-the-art hotspot detection solutions are all geometrical based. This CAD tool proposes a new philosophy by detecting yield limiters, also known as hotspots, through the model parameters of the device, presented in the SPICE netlist. This novel hotspot detection methodology is tested and delivers extraordinary fast and accurate results. Finally, the existing DFM solutions, mainly address the digital designs. Process variations play an increasingly important role in the success of analog circuits. Knowledge of the parameter variances and their contribution patterns is crucial for a successful design process. This information is valuable to find solutions for many problems in design, design automation, testing, and fault tolerance. The fourth CAD solution, proposed in this thesis, introduces a variability-aware DFM solution that detects, analyze, and automatically correct hotspots for analog circuits.

Case-Based Reasoning (CBR) has been successfully applied to many fields especially in the design domain. Poor assembly part design increases the cost, raises the manufacturing complexity and reduces the product quality. However, little research has been devoted to predict the potential design problems in the early design stage. The objective of this paper is to integrate the indexes of assemblability and manufacturability into adaptive phase in CBR to avoid inexperienced mistakes. Early experimental results indicate that quantitative feedback of these indexes can guide novices to depict a good assembly part design, let experienced designers confirm their experience judgments and finally impart the experience to novices through CBR methodology.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21752号 / 工博第4569号 / 新制||工||1712(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 西脇 眞二, 准教授 泉井 一浩, 教授 椹木 哲夫, 教授 松原 厚 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Seamless computer-based knowledge sharing between departments of a manufacturing enterprise is useful in preventing unnecessary design revisions. A lack of interoperability between independently developed knowledge bases, however, is a major impediment in the development of a seamless knowledge sharing system. Interoperability, being an ability to overcome semantic and syntactic differences during computer-based knowledge sharing can be enhanced through the use of ontologies. Ontologies in computer science terms are hierarchical structures of knowledge stored in a computer-based knowledge base. Ontologies have been accepted by all as an interoperable medium to provide a non-subjective way of storing and sharing knowledge across diverse domains. Some semantic and syntactic differences, however, still crop up when these ontological knowledge bases are developed independently. A case study in an aerospace components manufacturing company suggests that shape features of a component are perceived differently by the designing and manufacturing departments. These differences cause further misunderstanding and misinterpretation when computer-based knowledge sharing systems are used across the two domains. Foundation or core ontologies can be used to overcome these differences and to ensure a seamless sharing of knowledge. This is because these ontologies provide a common grounding for domain ontologies to be used by individual domains or department. This common grounding can be used by the mediation and knowledge verification systems to authenticate the meaning of knowledge understood across different domains. For this reason, this research proposes a knowledge verification framework for developing a system capable of verifying knowledge between those domain ontologies which are developed out of a common core or foundation ontology. This framework makes use of ontology logic to standardize the way concepts from a foundation and core-concepts ontology are used in domain ontologies and then by using the same principles the knowledge being shared is verified. The Knowledge Frame Language which is based on Common Logic is used for formalizing example ontologies. The ontology editor used for browsing and querying ontologies is the Integrated Ontology Development Environment (IODE) by Highfleet Inc. An ontological product modelling technique is also developed in this research, to test the proposed framework in the scenario of manufacturability analysis. The proposed framework is then validated through a Java API specially developed for this purpose. Real industrial examples experienced during the case study are used for validation.

This thesis report presents the work of analysing current challenges in Multidisciplinary Analysis systems. Exemplary the system of an aerospace supplier, GKN Aerospace Sweden AB, is examined and several suggestions for improve- ment are implemented. The Multidisciplinary Analysis system, with company internal name Engineering Workbench, employs a set-based approach in exploring the design-space for jet engine components. A number of design cases with varied geometrical and environmental parameters is generated using Design of Experiment sampling methods. Each design case is then subjected to a set of analyses. Using the analyses results, a surrogate model of the parts behaviour in relation to the input parameters is created. This enables the product developer to get a general view of the model’s behaviour and also to react to changes in product requirements. Design research methodology is applied to further develop the Engineering Workbench into a versatile design support system and expand the functionality to include producibility assessment. In its original state, the execution of a study requires explicit domain knowledge and programming skills in several disciplines. The execution of a study is often halted by minor process errors. Several methods to improve this status are suggested and tested. Among those are the introduction of an interface to improve the usability and expand the range of possible users. Further the integration of a four level system architecture supporting a modular structure. Producibility assessment is enabled by developing an expert system where geometrical and simulation results can be caught, analysed and evaluated to produce producibility metrics. Evaluation of the implemented solutions indicate a step in the right direction. Further development towards Multidisciplinary Optimisation, involving experts in information technologies as well as case- based reasoning techniques is suggested and discussed.

Many conflicting issues exist between product design and manufacturing department. In the early design stage, designers often do not have enough expertise to successfully address all these issues. This results in a product design with a low level of assemblability and manufacturability. Hence, an intelligent decision support system is needed for early design stages to improve a design. This paper proposed a web-based intelligent decision support system, CBR-DFMA, connecting with a case base, database and knowledge base. Early experimental results indicate that potential design problems can be detected in advance, design expertise can be effectively disseminated and effective training is offered to designer by employing this system.

L’originalité de notre travail consiste à développer une approche qui intègre l’ingénierie systèmes basée sur les modèles (MBSE) avec les principes de l’approche SBCE afin de réduire les boucles itératives entre les concepteurs inexpérimentés, les fabricants et les experts. D’autres parties prenantes participent également au développement du produit afin d’assurer environnement d’ingénierie simultanée. Cette approche offre un grand potentiel pour gérer les aspects de fabricabilité et de fiabilité, en raison de la capacité à développer des connaissances en parallèle, en particulier pour les technologies avancées et non matures. L’avantage d’utilisation des principes du SBCE est d’offrir des possibilités de communication entre les parties prenantes au début de la phase de conception. SysML est utilisé comme langage descriptif pour représenter les différentes phases de cette approche. Pour étudier la robustesse ces système, nous avons développé un modèle intitulé «Model Based for Robustness Analysis» (MBRA) qui a pour objectif de filtrer les solutions faibles ou coûteuses au fil du temps et d’assister l’ingénieur système lors de l'adoption d’une étude de compromis. Pour l’étude de la fabricabilité des systèmes complexes, nous avons développé un autre modèle intitulé « Model Based for Manufacturability analysis » / The originality of our work is to develop an approach that integrates model-based systems engineering (MBSE) with the principles of the SBCE approach to reduce iterative loops between inexperienced designers, manufacturers, and experts. Other stakeholders are also involved in product development to ensure simultaneous engineering environment. This approach offers great potential for managing manufacturability and reliability aspects, due to the ability to develop parallel knowledge, especially for advanced and non-mature technologies. The advantage of using SBCE principles is to provide opportunities for communication between stakeholders early in the design phase. SysML is used as a descriptive language to represent the different phases of this approach. To study the robustness of these systems, we have developed a model called "Model Based for Robustness Analysis" (MBRA) which aims to filter low or expensive solutions over time and to assist the system engineer when adopting a trade-offs study. For the assessment of the manufacturability of complex systems, we have developed another model entitled "Model Based for Manufacturability analysis"

Studies have shown that 70 – 80% of a product's life cycle costs are committed by the end of the product design phase (Anderson, 2014; National Research Council, 1991; Swift, 1987). This supports the general claim that decision making in the conceptual stage drives the cost throughout the life cycle. The use of concurrent engineering has been viewed as the answer to this problem, offering the Design for Excellence (DFX) as one approach for evaluating product designs across specific disciplines. This research focuses on a subset of DFX referred to as Design for Manufacturability to develop a means to assess manufacturing risk and cost impacts in the conceptual design phase while exploring some of the challenges associated with its implementation. First, the use of design for manufacturing methods typically occurs late in the design phase, where the detection of product deficiencies increases life cycle costs as teams work to mitigate the impacts to cost, quality, and production implementation schedules. Second, implementing methods and tools in the conceptual stage involves the need for decision-making at a point where the least amount of design and manufacturing information is available. Lastly, implementation of new methods requires a commitment of time for personnel to gain the familiarity needed to effectively use these methods to benefit product development activities. In response to this problem, this research introduces the House of Manufacturability (HOM) assessment method, heavily influenced by the House of Quality. This research synthesizes the results of a comprehensive literature review and the insight gained from a stakeholder evaluation involving individuals from the product development community to develop an early life cycle manufacturability assessment. The proposed HOM method utilizes an assessment matrix of manufacturability indicators (MIs) and stakeholder requirements (SRs) to arrive at manufacturability risk numbers (MRNs) that represent the concerns of the manufacturing enterprise. A pilot case study of a notional UAV design concept is explored to illustrate the application of the method and capture observations critical to the research. The results of the case study are compared to the stakeholder input to confirm alignment with the stakeholders’ expectations.

Detta examensarbete använder ett systematiskt tillvägagångssätt för att omkonstruera ett växellådshus till ett elektriskt fordon med avsikt att förbättra prestanda med avseende på hållfasthet, livslängd och styvhet. I examensarbetet ges även en kort beskrivning av hur växellådan fungerar, vilken roll den spelar i de elektriska fordonen, samt grundläggande teori som används  vid konstruktion av liknande växellådor. Den huvudsakliga arbetsmetoden som använts för att nå målen är topologioptimering och olika lösningar har simulerats för att förenkla den framtida omkonstruktionen. Analyser av de olika resultaten har lett fram till ett grovt förslag på hur växellådshuset kan utformas. Det resultatet förkastades efter det att några extra simuleringar gjorts. Även om inget slutgiltigt förslag hittades, har detta examensarbete tagit fram en bra grund och vägvisning för att senare lyckas med uppdraget. / This thesis targets a systematic approach for redesign of the gearbox housing for an electrical vehicle, with an intention to improve its performance in terms of structural integrity, durability and compliance. Throughout the work, a brief overview of gearbox purpose, position and significance in context of electric vehicles has been presented, some theoretical background concerning design of similar gearboxes is presented and underlying theoretical fundamentals are reviewed. Topology optimization has been utilized as the main method for achieving the goals and various solving runs were performed in order to ease the subsequent redesign. Interpretations of multiple result sets led to a rough outline guess of a possible solution candidate. After supplementary studies, that solution was later discarded. In the end, although no final redesign was generated, clear and comprehensive directions for achieving the targeted goal have been formulated.