Origami-inspired and deployable technology has become increasingly common in a variety of applications including satellite and antenna designs for space applications. The drive to utilize ultra-thin materials in the design of these deployable space structures has led to the development of membrane hinges. Membrane hinges show promise as an effective surrogate fold because of their potential advantages including requiring minimal volume and mass, allowing for small bending radii, and functioning without lubricant. Two challenges associated with membrane hinges include reliability after repeated cyclic loading and predictability of a large deployable with radially-unconstrained membrane hinges. The research presented includes the cyclic testing and a design analysis of membrane hinges in deployable systems. Additionally, demonstrations of membrane hinges in a variety of applications are included.

Origami is a useful tool for generating novel spatial mechanisms that can address needs in a variety of fields. However, replicating paper folding in other materials requires surrogate folds---some way to approximate folding in otherwise rigid materials. This work presents a collection of potential surrogate fold designs suitable for use in origami-inspired applications. The designs are sorted into families and rated against several design characteristics of interest to engineers and designers to create the Surrogate Fold Catalog. The catalog is formatted to be searchable and filterable based on manufacturability, kinematic motion, and additional utility. Using this collection of surrogate folds can improve the efficiency of the design process and the efficacy of the final design. The value of integrating surrogate folds early in the design process is demonstrated in the design of gossamer reflectarray antennas. Mathematical models are provided that predict the location and amount of slip required to allow the array to roll compactly and minimize plastic deformation. Surrogate folds for different folding patterns are designed to allow for the predicted slip. Several cases of the design and use of surrogate folds with a range of materials and applications are presented, including forged carbon fiber and stained glass. A physical collection of various surrogate folds is shown as the Foldable Book of Surrogate Folds. Digital versions of the Surrogate Folds and the Foldable Book of Surrogate Folds are available in supplementary material.

A pragmatic method for designing compliant mechanisms is developed in this thesis, by selecting among existing mechanisms one that may be modified as required. This method complements existing techniques by answering questions of the existence and multiplicity of solutions for the given specifications of a practical problem. The premise for the method is a 2D map that juxta- poses the problem-specifications and the characteristics of compliant mechanisms in a database. The selection of the most suitable mechanisms is similar to Ashby's method of material selection. In our method, stuffiness, inertia, and the inherent kinematic characteristics of compliant mechanisms are analogous to material properties in Ashby's method. These characteristics capture the lumped behavior of compliant mechanisms in static and dynamic situations using spring-lever (SL) and spring-mass-lever (SML) models. The work includes the development of computation- ally efficient methods to compute the SL and SML model characteristics of single-input and single-output compliant mechanisms. Also developed in this work is a method to determine a feasible map by solving the governing equations of equilibrium and several inequalities pertaining to problem- specifications. The map helps not only in assessing the feasibility of the specifications but also in re-designing the mechanisms in predetermined ways to nd multiple solutions, all of which account for practical considerations. The method pays due attention to the overall size, strength considerations, manufacturability, and choice of material. It also enables minimal alterations of the problem-specifications when the user prefers a particular mechanism in the database. All these features are implemented in a web-based Java program with a graphical user interface that can be accessed at http://www.mecheng.iisc.ernet.in/ m2d2/CM design. Six case- studies that include micro machined inertial sensors, miniature valve mechanisms, ultra-sensitive force sensors, etc., are documented in detail to demonstrate the usefulness of the method in practice.

Os mecanismos flexíveis são dispositivos capazes de transmitir força e movimento através da deformação elástica. Têm grande importância a uma série de aplicações nas quais os mecanismos de corpos rígidos não seriam viáveis, como por exemplo, os sistemas microeletromecânicos. Existem várias maneiras pelas quais os mecanismos flexíveis podem ser projetados, sendo a otimização topológica um método bastante difundido por ser de aplicação sistemática, ou seja, não requer do projetista qualquer ação analítica durante a etapa de projeto. Na maioria dos casos, o método da otimização topológica combina o método dos elementos finitos com um método de programação matemática. Logo, faz-se necessário discretizar a região do espaço na qual o material disponível será distribuído para determinar o mecanismo flexível adequado à aplicação desejada. Freqüentemente, o mecanismo projetado apresenta duas regiões sólidas unidas por um único nó pertencente à malha de elementos finitos. Durante a transmissão do movimento, este nó age como uma dobradiça conectada às duas regiões. Trata-se de um efeito indesejado, pois compromete a modelagem e a fabricação do componente mecânico. Assim, neste trabalho, foram estudadas técnicas destinadas à redução da ocorrência das \"dobradiças\" no projeto de mecanismos flexíveis por otimização topológica. Foi implementado em linguagem C um código que permite projetar mecanismos flexíveis submetidos a um único carregamento ou múltiplos carregamentos (mecanismos multi-flexíveis). Com o objetivo de analisar e explorar outros aspectos da formulação implementada no código, investigou-se também a sua utilização no projeto de estruturas rígidas. Como resultado, é mostrada a influência dos diversos parâmetros de otimização no projeto de mecanismos flexíveis sem dobradiças, permitindo analisar a eficácia da formulação implementada. / Compliant mechanisms are devices capable of transmitting force and displacement through elastic deformation. They are extremely important for a number of applications in which the mechanisms of rigid bodies would not be feasible, such as microelectromechanical systems. There are several ways through which compliant mechanisms can be designed, being topology optimization a highly diffused method because of its systematic application, once, it does not require from the designer any analytical action during the stage of the project. In most cases, topology optimization method combines the finite element method with a mathematical program method. Therefore, it is necessary to discretize the region of the space in which the available material will be distributed to determine the appropriate compliant mechanism for the desired application. However, the mechanism designed often presents two solid regions united by one single node. During movement transmission, this node acts as a hinge connected to both regions. This is an undesired effect, as it compromises the modeling and manufacturing of the mechanical component. Thus, this work covers techniques aiming at reducing the occurrence of hinges in the design of compliant mechanisms through topology optimization. A code in C language was implemented, which allows the design of compliant mechanisms subjected to one single load or multiple loads (multi-compliant mechanisms). With the purpose of analyzing and exploring other aspects of the formulation implemented in the code, its use in the design of rigid structures was also investigated. As a result, the influence of several optimization parameters in the design of compliant mechanisms without hinges is shown. This allows to analyze the efficiency of the formulation implemented.

Compliant mechanisms offer several design advantages which may be exploited in prosthetic joint research and development: they are light-weight, have low cost, are easy to manufacture, have high-reliability, and have the ability to be designed for displacement loads. Designing a mechanism to perform optimally under displacement rather than force loading allows underlying characteristics of the swing phase of gait, such as the maximum heel rise and terminal swing to be developed into a prosthetic knee joint. The objective of this thesis was to develop a mechanical add-on compliant link to an existing prosthetic knee which would perform to optimal standards of prosthetic gait, specifically during the swing phase, and to introduce a feasible method for increasing proprioceptive feedback to the amputee via transferred moments and varying surface tractions on the inner part of a prosthetic socket. A finite elements model was created with ANSYS to design the prosthetic knee compliant add-on and used to select the geometry to meet prosthetic-swing criteria. Data collected from the knee FEA model was used to apply correct loading at the knee in a SolidWorks model of an above-knee prosthesis and residual limb. Another finite element model was creating using COSMOSWorks to determine the induced stresses within a prosthetic socket brought on by the compliant link, and then used to determine stress patterns over 60 degrees of knee flexion (standard swing). The compliant knee add-on performed to the optimal resistance during swing allowing for a moment maxima of 20.2 Newton-meters (N-m) at a knee flexion of 62 degrees. The moments applied to the prosthetic socket via the compliant link during knee flexion and extension ranged from 5.2 N-m (0 degrees) in flexion, to 20.2 N-m (62 degrees) in extension and induced a varying surface tractions on the inner surface of the socket over the duration, thus posing a possible method of providing proprioceptive feedback via surface tractions. Developing a method for determining the level of proprioceptive feedback would allow for less expensive and more efficient methods of bringing greater control of a prosthesis to its user.

The aim of this study is to design a compliant lock mechanism for a dishwasher, using a systematic approach. Functionally binary pinned-pinned segment that exhibits bistable behavior is utilized. Pseudo-rigid-body model of the whole mechanism and the half segment is developed separately and the corresponding calculations are carried out. Among current solutions a different method namely &ldquo / arc fitting method&rdquo / is developed and it is utilized to construct the model. A software code is written to get the exact solutions, which require the evaluation of elliptic integrals. Results are compared with the analytical model and confirmed with physical prototype. Predefined tip forces are seen to provide the transition from one stable position to other. Durability, reliability and compactness characteristics are particularly considered.

This paper presents designs for Multistable Shape-Shifting Surfaces (MSSS) by introducing bistability into the Shape-Shifting Surface (SSS). SSSs are defined as surfaces that retain their effectiveness as a physical barrier while undergoing changes in shape. The addition of bistability to the SSS gives the surface multiple distinct positions in which it remains when shifted to, i.e. by designing bistability into a single SSS link, the SSS unit cell can change into multiple shapes, and stabilize within the resulting shape, while maintaining integrity against various forms of external assaults normal to its surface. Planar stable configurations of the unit cell include, expanded, compressed, sheared, half-compressed, and partially-compressed, resulting in the planar shapes of a large square, small square, rhombus, rectangle, and trapezoid respectively. Tiling methods were introduced which gave the ability to produce out-of-plane assemblies using planar MSSS unit cells. A five-walled rigid storage container prototype was produced that allowed for numerous stable positions and volumes. Applications for MSSSs can include size-changing vehicle beds, expandable laptop screens, deformable walls, and volume-changing rigid-storage containers. Analysis of the MSSS was done using pseudo-rigid-Body Models (PRBMs) and Finite Element Analysis (FEA) which ensured bistable characteristics before prototypes were fabricated.

Os mecanismos flexíveis são dispositivos capazes de transmitir força e movimento através da deformação elástica. Têm grande importância a uma série de aplicações nas quais os mecanismos de corpos rígidos não seriam viáveis, como por exemplo, os sistemas microeletromecânicos. Existem várias maneiras pelas quais os mecanismos flexíveis podem ser projetados, sendo a otimização topológica um método bastante difundido por ser de aplicação sistemática, ou seja, não requer do projetista qualquer ação analítica durante a etapa de projeto. Na maioria dos casos, o método da otimização topológica combina o método dos elementos finitos com um método de programação matemática. Logo, faz-se necessário discretizar a região do espaço na qual o material disponível será distribuído para determinar o mecanismo flexível adequado à aplicação desejada. Freqüentemente, o mecanismo projetado apresenta duas regiões sólidas unidas por um único nó pertencente à malha de elementos finitos. Durante a transmissão do movimento, este nó age como uma dobradiça conectada às duas regiões. Trata-se de um efeito indesejado, pois compromete a modelagem e a fabricação do componente mecânico. Assim, neste trabalho, foram estudadas técnicas destinadas à redução da ocorrência das \"dobradiças\" no projeto de mecanismos flexíveis por otimização topológica. Foi implementado em linguagem C um código que permite projetar mecanismos flexíveis submetidos a um único carregamento ou múltiplos carregamentos (mecanismos multi-flexíveis). Com o objetivo de analisar e explorar outros aspectos da formulação implementada no código, investigou-se também a sua utilização no projeto de estruturas rígidas. Como resultado, é mostrada a influência dos diversos parâmetros de otimização no projeto de mecanismos flexíveis sem dobradiças, permitindo analisar a eficácia da formulação implementada. / Compliant mechanisms are devices capable of transmitting force and displacement through elastic deformation. They are extremely important for a number of applications in which the mechanisms of rigid bodies would not be feasible, such as microelectromechanical systems. There are several ways through which compliant mechanisms can be designed, being topology optimization a highly diffused method because of its systematic application, once, it does not require from the designer any analytical action during the stage of the project. In most cases, topology optimization method combines the finite element method with a mathematical program method. Therefore, it is necessary to discretize the region of the space in which the available material will be distributed to determine the appropriate compliant mechanism for the desired application. However, the mechanism designed often presents two solid regions united by one single node. During movement transmission, this node acts as a hinge connected to both regions. This is an undesired effect, as it compromises the modeling and manufacturing of the mechanical component. Thus, this work covers techniques aiming at reducing the occurrence of hinges in the design of compliant mechanisms through topology optimization. A code in C language was implemented, which allows the design of compliant mechanisms subjected to one single load or multiple loads (multi-compliant mechanisms). With the purpose of analyzing and exploring other aspects of the formulation implemented in the code, its use in the design of rigid structures was also investigated. As a result, the influence of several optimization parameters in the design of compliant mechanisms without hinges is shown. This allows to analyze the efficiency of the formulation implemented.

La radiologie interventionnelle percutanée permet le diagnostic ou le traitement de tissus cancéreux grâce à l'utilisation d'aiguilles et d'un guidage par imageur. Bénéfique pour le patient, ce type de procédure clinique est en revanche complexe pour le radiologue. Afin de lui apporter une assistance et de contrôler l'aiguille de manière déportée, nous proposons dans ces travaux de réaliser des dispositifs robotisés compliants, donc monoblocs, et multi-matériaux en exploitant la fabrication additive multi-matériaux. Pour y parvenir, nous proposons plusieurs solutions pour réaliser les fonctions cinématique, d'actionnement et de perception. En particulier, nous proposons une nouvelle liaison compliante, la liaison HSC, ainsi qu'un nouvel actionneur pneumatique pour l'insertion d'aiguille. Nous démontrons finalement les apports de la fabrication additive pour la robotique médicale en combinant l'ensemble de ces solutions dans un dispositif assurant un contrôle à distance de l'aiguille. / Percutaneous interventional radiology permits the diagnosis or the treatment of cancer tissues thanks to the use of needles and imaging devices. Being minimally invasive, such procedures are beneficial for the patient, but for the radiologist, they are highly complex. In order to assist the physician and remotely control the needle, we propose in this work the design and the manufacturing of multi-material compliant devices by taking advantage of multi-material additive manufacturing. To perform the design of such device, we propose several solutions in terms of kinematics, actuation and sensing. In particular, we developed a new compliant joint, the HSC joint, as well as a new pneumatic actuator for needle insertion. In the end, we demonstrate in the thesis the contributions of multi-material additive manufacturing for medical robotics, by combining all those solutions into a single device that remotely controls both the orientation and the insertion of the needle

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18585号 / 工博第3946号 / 新制||工||1606(附属図書館) / 31485 / 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, 教授 田畑 修, 教授 松原 厚 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM