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京都大学 / 新制・課程博士 / 博士(理学) / 甲第25128号 / 理博第5035号 / 新制||理||1718(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)准教授 板東 俊和, 教授 深井 周也, 教授 秋山 芳展 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

his thesis presents the design, fabrication, and testing of a robotic arm that is inherently safe, lightweight and affordable. The arm’s three joints are driven by novel hybrid vacuum-electric actuators that each combine origami-inspired soft pneumatic actuators (OSPAs) with a DC motor. The arm is a type of collaborative robot, or cobot, that is suitable for low payload, low speed applications. The OSPA was redesigned in the first stage of the research. In particular, the new endcaps are 59% shorter than the previous design. This made the actuators more compact and increased their stroke-to-length ratio. Next, the OSPA fabrication process was significantly changed. The heating of the heat shrink tubing was changed from immersion in boiling water to heating with a heat gun, and a motorized stand with several assisting parts was developed. These changes improved the consistency of the fabrication, reduced the skills required, and improved the safety. The joints of the arm and its structural components were designed next. The rotation of each joint is achieved by connecting multiple OSPAs to custom-made pulleys using cables and connecting a DC motor in parallel using a timing belt. Joint 2, the shoulder joint, had to produce the largest torque. This was accomplished by applying optimization methods to design a variable-radius pulley. The prototype arm utilized laser-cut acrylic and 3D printed components to keep its cost and weight low. Finally, after a simple pressure control system was developed, the prototype arm’s performance was extensively tested. The joints’ ranges of motion, velocities, accelerations, and blocked torques are tested at multiple pressures and motor currents, and the results discussed. The thesis concludes with a summary of the research’s achievements and limitations, and recommendations for future improvements to the robotic arm’s design. / Thesis / Master of Applied Science (MASc) / This thesis presents the design, fabrication, and testing of a robotic arm that is inherently safe, lightweight and affordable. The arm’s three joints are driven by novel actuators that each combine soft pneumatic actuators (powered by vacuum pressure) with a DC motor. The arm is suitable for low payload, low speed applications. First, the pneumatic actuators were redesigned to make them more compact. Next, their fabrication process was changed to improve the consistency of the results, reduce the skills required, and improve the safety. The joints of the arm and its structural components were then designed. To produce the torque required for the shoulder joint, optimization methods were used to create a variable-radius pulley. The prototype arm utilized laser-cut acrylic and 3D-printed components to keep its cost and weight low. Finally, after a simple pressure control system was developed, the prototype arm’s performance was extensively tested.

This research delves into the feasibility and effectiveness of utilizing wind-powered shading systems in architectural design to enhance energy efficiency and promote environmental sustainability. With an ever increasing demand for energy in commercial buildings, particularly in heating, cooling, and lighting, innovative solutions are crucial in addressing these challenges. The proposed solution centers on dynamic shading systems that adjust autonomously to environmental factors, thanks to advancements in construction and information technologies. Piezoelectric wind harnessing devices are at the heart of this investigation, powering kinetic shading systems that offer a renewable and eco-friendly alternative to traditional energy sources. However, implementing such systems presents technical challenges such as device optimization, compatibility with dynamic movement, and reliability in real-world applications. Through empirical research and experimentation, these challenges are comprehensively explored and addressed. The study seeks to assess the practicality and effectiveness of wind-powered shading systems in reducing energy consumption, improving thermal comfort, and enhancing overall building performance. By considering factors such as architectural integration, heat, light management, and adaptability to environmental conditions, the research aims to contribute to the advancement of sustainable building practices. Ultimately, the findings provide valuable insights into the potential of wind-powered shading systems to mitigate energy usage and promote environmental stewardship in architectural design. / Master of Architecture / This Thesis Explores the design and evaluation of origami-inspired kinetic shading system driven by piezoelectric technology to convert wind power to electricity. By examining the behavior and utility of this piezoelectric dynamic folding shading system, it enhances our understanding of how to integrate renewable energy into building designs for a more sustainable future.

This dissertation is concerned with a type of energy absorption device made of thin-walled tubes. The tubes will undergo plastic deformation when subjected to an impact loading, and therefore absorb kinetic energy. It has been found that, if the surface of a tube is pre-folded according to an origami pattern, the failure mode of the tube can be altered, leading to a noticeable increase in energy absorption while at the same time, reducing the force needed to initiate plastic deformation within the tube. The main work is presented in four parts. First of all, an experimental study of a type of previously reported thin-walled square tube with pre-manufactured pyramid patterns on the surface has been conducted. Quasi-static axial crushing tests show that the octagonal mode, although numerically proven to be efficient in terms of energy absorption, cannot be consistently triggered. Secondly, a new type of thin-walled tubular energy absorption device, known as the origami tube, which has origami pattern pre-fabricated on the surface, has been studied. A family of origami patterns has been designed for tubes with different profiles. The performances of a series of origami tubes with various configurations subjected to quasi-static axial crushing have been investigated numerically. It is found that a new failure mode, referred to as the complete diamond mode, can be triggered, and both over 50% increase in the mean crushing force and about 30% reduction in the peak force can be achieved in a single tube design in comparison with those of a conventional square tube with identical surface area and wall thickness. A theoretical study of the axial crushing of square origami tubes has been conducted and a mathematical formula has been derived to calculate the mean crushing force. Comparison between theoretical prediction and numerical results shows a good agreement. Quasi-static axial crushing experiments on several square origami tube samples have been carried out. The results show that the complete diamond mode is formed in the samples and both peak force reduction and mean crushing force increase are attained. Thirdly, a new type of curved thin-walled beam with pre-manufactured origami pattern on the surface, known as the origami beam, has been designed and analyzed. A numerical study of a series of origami beams with a variety of configurations subjected to quasi-static lateral bending has been conducted. The results show that two new failure modes, namely, the longitudinal folding mode and the mixed mode, can be induced, and both reduced peak force and increased energy absorption are achieved. Finally, a number of automobile frontal bumpers, which have the origami tube and the origami beam as key components, have been designed and analyzed. Three impact tests have been conducted on each bumper. The numerical results show that both types of origami structures can perform well in realistic loading scenarios, leading to improved energy absorption of the bumpers.

Este trabalho inicia com uma contextualização histórica e motivação, seguida por revisão bibliográfica nos tópicos discutidos: segurança veicular, crash box, crashworthiness, absorvedores de energia, tubos de impacto, metamodelos, algoritmos genéticos, Planejamento de Experimentos (DoE - Design of Experiments), origami e engenharia, e métodos de otimização na engenharia. Em seguida, o pesquisador propõe um experimento baseado em simulações, avaliando diversas crash box em forma de origami criadas a partir da variação de seus parâmetros dimensionais. Através de um algoritmo baseado em metamodelos, o autor realiza uma análise com o objetivo de maximizar a energia absorvida específica (Specific Energy Absorption - SEA) e a uniformidade de carga (Load Uniformity - LU). A fronteira de Pareto resultante dos dois objetivos é analisada de acordo a exemplos de critérios de decisão, e a configuração escolhida é então comparada a uma crash box da indústria. A configuração escolhida apresenta uma massa quatro vezes menor, e uma uniformidade de carga semelhante à crash box da indústria. Conclui com novas proposições de trabalhos, envolvendo outros métodos de otimização disponíveis. / This research begins with a historical background and motivation, followed by a bibliographic review on the discussed topics: vehicle safety, crash box, crashworthiness, energy absorbers, impact tubes, metamodels, Design of Experiments (DOE), origami and engineering, and optimization in engineering. Next, the researcher proposes a simulation-based experiment, evaluating origami crash boxes created through the variation of several dimensional parameters. Through a metamodel-based algorithm, the author performs an analysis with the objective of maximizing the Specific Energy Absorption (SEA) and the load uniformity (LU). The resultant Pareto frontier of the two objectives is analyzed according to examples of decision criteria, and the chosen design is compared to a crash box from industry. The chosen design presents four times less mass, and a load uniformity similar to the crash box from industry. The research concludes with propositions for new themes, involving other optimization methods available.

DNA provides an ideal substrate for nanoscale construction and programmable dynamic mechanisms. DNA mechanisms can be used to produce DNA motors which do mechanical work, e.g. transportation of a substrate along a track. I explore a method for control of a DNA mechanism ubiquitous in DNA motor designs, toehold-mediated strand displacement, by which one strand in a duplex can be swapped for another. My method uses a mismatch between a pair of nucleotides in the duplex, which is repaired by displacement. I find that displacement rate can be fine-tuned by adjusting the position of the mismatch in the duplex, enabling the design of complex kinetic behaviours. A bipedal motor [1, 2] is designed to walk along a single-stranded DNA track. Previously the motor has only taken a single step, due to a lack of designs to extend the single-stranded track. I present a novel design for track held under tension using a 3D DNA origami tightrope, and verify its assembly. The bipedal motor design is adapted and a method to specifically place motors on tightropes is demonstrated. Motor operation is investigated on truncated tracks and tightrope tracks by electrophoresis and spectrofluorometry. The motor does not accumulate appreciably at the track end; this is tentatively attributed to rearrangement of the motor between track sites without interaction with fuel. Tightrope origami can hold single-stranded DNA under pN tension. I use tightropes to study hybridization kinetics under tension and find dramatic, non-monotonic changes in hybridization rate constants and dissociation constants with tension in the range ∼0-15 pN. Extended tracks for a 'burnt-bridges' motor which destroys its track as it moves [3] are created on the inside of DNA nanotubes, which can be polymerised to create tracks up to a few mm in length, and on tiles which I attempt to join in a specific order. Crossing of the motor between tubes is verified, and microscopy experiments provide some evidence that track is being cleaved by the motor, a requirement for movement along the track. Tile based tracks are imaged by super-resolution DNA PAINT [4], providing proof-of-principle for track observation to infer motor movement.

Much of our knowledge of cellular biology arises from direct observation of active cellular functions. Tools and techniques have steadily developed over the past several hundreds of years to aid in our understanding and control of the nanoworld and are referred to as nanotechnologies. In the context of nanotechnology, DNA is not used as a carrier for genetic information (as it is in cell), but as a construction material. DNA offers unprecedented control over the construction of simplified biomimetic models for the study of biological processes. This thesis first introduces and defines the field of DNA nanotechnology, with particular emphasis on the interaction of snthetic DNA nanostructures with biological membranes. Inspired by the protein clathrin, three-fold symmetric DNA tile made of eight, short DNA strands and capable of polymerising is described and studied, with the aim to interact with and controllably bend a membrane bilayer. This structure presented challenges during construction so an enhanced three-armed DNA structure built with DNA origami was designed. The succesful assembly of a rigid and functionalisable nanostructure is described. This origami structure was polymerised into large constructs in solution and on a supported lipid membrane. The shape of the structure was modulated to vary its curvature and apply a bending force to a lipid vesicle when anchored to it. Following the conclusion of this study, we present the construction of a small, unique DNA structure for enhanced electron microscopy imaging in cell lysate. This project is part of a developing technique to couple the interaction specificity of dyes in super-resolution microscopy and the high-resolution output of electron microscopy. Finally, the optimisation procedures and recommendations for TEM imaging of samples of DNA origami and lipid structures are discussed.