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Limited resources are currently available to assist engineers in implementing compliant members into mechanical designs. As a result, engineers often have little to no direction incorporating compliant mechanisms. This thesis develops a conceptual design framework and process that utilizes a proposed classification scheme and a library of mechanisms to help engineers incorporate compliant mechanisms into their applications. As the knowledge related to the synthesis and analysis of compliant mechanisms continues to grow and mature, and through the classification scheme established in this thesis, compliant mechanisms may become more extensively used in commercial mechanical designs. This thesis also demonstrates a design approach engineers can use to convert an existing rigid-body mechanism into a compliant mechanism by using the established classification scheme and a library of compliant mechanisms. This approach proposes two possible techniques that use rigid-body replacement synthesis in conjunction with a compliant mechanism classification scheme. One technique replaces rigid-body elements with a respective compliant element. The other technique replaces a complex rigid-body mechanism by decomposing the mechanism into simpler functions and then replacing a respective rigid-body mechanism with a compliant mechanism that has a similar functionality. These techniques are then demonstrated by developing and designing a competitive and feasible compliant road bicycle brake system.

This thesis presents the development and validation of a novel interface modelling methodology integrated with a system architectural analysis framework that emphasises the need to manage the integrity of deriving and allocating requirements across multiple levels of abstraction in a structured manner. The state of the art review in this research shows that there is no shared or complete interface definition model that could integrate diverse interaction viewpoints for defining system requirements with complete information. Furthermore, while existing system modelling approaches define system architecture with functions and their allocation to subsystems to meet system requirements, they do not robustly address the importance of considering well-defined interfaces in an integrated manner at each level of systems hierarchy. This results in decomposition and integration issues across the multiple levels of systems hierarchy. Therefore, this thesis develops and validates following: -Interface Analysis Template as a systematic tool that integrates diverse interaction viewpoints for modelling system interfaces with intensive information for deriving requirements. -Coupling Matrix as an architecture analysis framework that not only allocates functions to subsystems to meet requirements but also promotes consistent consideration of well-defined interfaces at each level of design hierarchy. Insights from the validation of developed approach with engineering case studies within an automotive OEM are discussed, reflecting on the effectiveness, efficiency and usability of the methods.

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The focus of this thesis project is exploration of the design space of the area of multilingual family communication. The project elaborates and adds to the concepts of design space and design openings and applies these concepts to the research area. In a common design process the focus at design space predominates at the early stage of design development, when problems and solutions are not found yet and the goal is to create a handful of design openings. Those design openings are leading the designer in different directions of the development of the design proposals. Some design openings and proposals are introduced in this project as illustrations of the design space exploration.The idea of game probes is discovered in this work as a tool of design space exploration. Multilingual children have been attracting my attention as an interaction designer during the last few years. Playful interaction is one of the basic communication channels between a parent and a child of the pre-school and early school age. Artefacts are powerful elements of design research, moreover tangible, visual and embodied experiences enable creativity, exploration and re-thinking of given ideas. All these key concepts are widely discovered through such methods as cultural and technology probes and critical design. The notion of game probes was established in this project through finding connections between its goals and practices of probing methods, playful activities and critical game design.

This research addresses a problem that centers on the persistent disparities in computer use and access among racial minorities, particularly African-Americans and Latinos, and persons of low socio-economic status (SES) here in the USA. "Access" to computer technology maintains a dual meaning. Access may refer to having a computer and software available for use or it may refer to having a computer interface that effectively facilitates user learning. This study conceptualizes "access" as the latter — having an interface that facilitates user learning. One intervention for this problem of access, from a Human Factors perspective, is in recognizing and accounting for culture's influence on one's cognition. Both qualitative and quantitative approaches were integrated to effectively determine a process for engaging typically marginalized groups, interface metaphor preferences of African-Americans, and user performance with varying types of interface metaphors. The qualitative aspects of this study provided a basis for understanding how entry was obtained into the participants' community and for obtaining richer descriptions of user successes and challenges with the various interface designs. The researcher developed a culturally valid interface design methodology, i.e., Acculturalization Interface Design (A.I.D.) methodology, which was used to identify meaningful computer interface metaphors for low SES African-Americans. Through the A.I.D. methodology and an associated field study, a group of African-American novice computer users determined that the home, the bedroom and comfort were meaningful computer interface metaphors to integrate into a letter writing task. A separate group of African-Americans performed benchmark tasks on an interface design that utilized the home, bedroom and comfort metaphors or Microsoft Word 2003. The African-American group performed significantly better on the novel interface than on Microsoft Word 2003 for several benchmark tasks. Qualitative analyses showed that low acculturation African-Americans were particularly challenged with those same tasks. Regression analyses used to determine the relationship between psychosocial characteristics and user performance were inconclusive. Subject matter experts (SME), representing low SES Latinos, discussed potential learnability issues for both interface designs. Furthermore, results from the African-American group and the SMEs highlight the critical importance of using terminology (i.e., verbal metaphors) and pictorial metaphors that are culturally and socially valid. / Ph. D.

Electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) are gaining popularity because they are more environmentally friendly, less noisy and more efficient. These vehicles have batteries can be charged by on-board battery chargers that can be conductive or inductive. In conductive chargers, the charger is physically connected to the grid by a connector. With the inductive chargers, energy can be transferred wirelessly over a large air-gap through inductive coupling, eliminating the physical connection between the charger and the grid. A typical on-board battery charger consists of a boost power factor correction (PFC) converter followed by a dc-dc converter. This dissertation focuses on the design, modeling and control of a bidirectional dc-dc converter for conductive battery charging application. In this dissertation, a detailed design procedure is presented for a bidirectional CLLLC-type resonant converter for a battery charging application. This converter is similar to an LLC-type resonant converter with an extra inductor and capacitor in the secondary side. Soft-switching can be ensured in all switches without additional snubber or clamp circuitry. Because of soft-switching in all switches, very high-frequency operation is possible, thus the size of the magnetics and the filter capacitors can be made small. To further reduce the size and cost of the converter, a CLLC-type resonant network with fewer magnetics is derived from the original CLLLC-type resonant network. First, an equivalent model for the bidirectional converter is derived for the steady-state analysis. Then, the design methodology is presented for the CLLLC-type resonant converter. Design of this converter includes determining the transformer turns ratio, design of the magnetizing inductance based on ZVS condition, design of the resonant inductances and capacitances. Then, the CLLC-type resonant network is derived from the CLLLC-type resonant network. To validate the proposed design procedure, a 3.5 kW converter was designed following the guidelines in the proposed methodology. A prototype was built and tested in the lab. Experimental results verified the design procedure presented. The dynamics analysis of any converter is necessary to design the control loop. The bandwidth, phase margin and gain margin of the control loops should be properly designed to guarantee a robust system. The dynamic analysis of the resonant converters have not been extensively studied, with the previous work mainly concentrated on the steady-state models. In this dissertation, the continuous-time large-signal model, the steady-state operating point, and the small-signal model are derived in an analytical closed-form. This model includes both the frequency and the phase-shift control. Simulation and experimental verification of the derived models are presented to validate the presented analysis. A detailed controller design methodology is proposed in this dissertation for the bidirectional CLLLC-type resonant converter for battery charging application. The dynamic characteristics of this converter change significantly as the battery charges or discharges. And, at some operating points, there is a high-Q resonant peaking in the open-loop bode-plot for any transfer functions in this converter. So, if the controller is not properly designed, the closed-loop system might become unstable at some operating points. In this paper, a controller design methodology is proposed that will guarantee a stable operation during the entire operating frequency range in both battery charging mode (BCM) and regeneration mode (RM). To validate the proposed controller design methodology, the output current and voltage loop controllers are designed for a 3.5 kW converter. The step response showed a stable system with good transient performance thus validating the proposed controller design methodology. / Ph. D.

This paper is an investigation into a quantitative selection process of either a mechanical or electrical system architecture for the transmission of propulsion power in naval combatant vessels. A database of historical naval ship characteristics was statistically analyzed to determine if there were any predominant ship parameters that could be used to predict whether a ship should be designed with a mechanical power transmission system or an electric one. A Principal Component Analysis was performed to determine the minimum number of dimensions required to define the relationship between the propulsion transmission architecture and the independent variables. Combining the results of the statistical analysis and the PCA, neural networks were trained and tested to separately predict the transmission architecture or the installed electrical generation capacity of a given class of naval combatant.