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Full-Text Articles in Engineering
Methods For Designing Compact And Deployable Origami-Inspired Flat-Foldable Spacecraft Antennas And Other Systems, Collin Ryan Ynchausti
Methods For Designing Compact And Deployable Origami-Inspired Flat-Foldable Spacecraft Antennas And Other Systems, Collin Ryan Ynchausti
Theses and Dissertations
There are times when it is desirable for devices to be stowed compactly, ``transported'' to the location of their desired use, and then deployed to another stable shape or configuration to perform their designed function. Origami-based mechanisms are beneficial in these cases due to their compact, folded nature and large deployments. Unlike traditional mechanical design, compliant mechanism and origami-based design approaches inherently have coupled characteristics, creating complex design problems. The research presented here discusses metrics, methods, and designs to aid in the design of origami-adapted and compliant mechanisms, focusing on the design case of deployable space systems. First, the hexagonal …
Laser Forming Of Compliant Mechanisms And Flat-Foldable Furniture, Daniel Calvin Ames
Laser Forming Of Compliant Mechanisms And Flat-Foldable Furniture, Daniel Calvin Ames
Theses and Dissertations
Compliant mechanisms are useful for improving existing machines and creating new ones that were not previously possible. They also help us to think of new methods and technologies needed to both improve existing systems as well as manufacture systems that have not been done before. The purpose of this thesis is to show novel implementations of compliant mechanisms into folding systems, and to show new methods for fabricating such mechanisms with nontraditional materials and on difficult scales. Folding systems are shown in furniture applications with chairs, stools, and childcare furniture applications as results of research into how such structures could …
Characterizing Behaviors And Functions Of Joints For Design Of Origami-Based Mechanical Systems, Nathan Chandler Brown
Characterizing Behaviors And Functions Of Joints For Design Of Origami-Based Mechanical Systems, Nathan Chandler Brown
Theses and Dissertations
This thesis addresses a number of challenges designers face when designing deployable origami-based arrays, specifically joint selection, design, and placement within an array. In deployable systems, the selection and arrangement of joint types is key to how the system functions. The kinematics and performance of an array is directly affected by joint performance. This work develops joint metrics which are then used to compare joint performances, constructing a tool designers can use when selecting joints for an origami array. While often a single type of joint is used throughout an array, this work shows how using multiple types of joints …
Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor
Exploration Of Constant-Force Wristbands For A Wearable Health Device, Thomas Alexander Naylor
Theses and Dissertations
Wearable Health Devices (WHDs) are an emerging technology that enables continuous monitoring of vital signs during daily life. Issues with constant and consistent data acquisition have been found while WHD technology has developed. The force of the measurement area and movement of the sensors are key mechanical issues that need to be solved for WHDs to become a viable way to continuously monitor health conditions. This work explores Constant-Force Mechanisms (CFMs) as a solution to problems the current WHD industry faces. Additionally, the relationship between force provided from the mechanism, sensor pressure on the wrist, patient comfort, and sensor readings …
On Creases And Curved Links: Design Approaches For Predicting And Customizing Behaviors In Origami-Based And Developable Mechanisms, Jared J. Butler
On Creases And Curved Links: Design Approaches For Predicting And Customizing Behaviors In Origami-Based And Developable Mechanisms, Jared J. Butler
Theses and Dissertations
This work develops models and tools to help designers address the challenges associated with designing origami-based and developable mechanisms. These models utilize strain energy, kinematics, compliant mechanisms, and graphical techniques to make the design of origami-based and developable mechanisms approachable and intuitive. Origami-based design tools are expanded through two methods. First presented is a generalized approach for identifying single-output mechanical advantage for a multiple-input compliant mechanism, such as many origami-based mechanisms. The model is used to predict the force-deflection behavior of an origami-based mechanism (Oriceps) and is verified with experimental data from magnetic actuation of the mechanism. Second is a …
Developing Origami-Based Approaches To Realize Novel Architectures And Behaviors For Deployable Space Arrays, Nathan Alan Pehrson
Developing Origami-Based Approaches To Realize Novel Architectures And Behaviors For Deployable Space Arrays, Nathan Alan Pehrson
Theses and Dissertations
Origami-based approaches for the folding of thick materials for specific application to large deployable space arrays is explored in this work. The folding approaches presented utilize strain energy, spatial kinematics, membranes, compliant mechanisms, and or in combination together to fold finite-thickness materials viewed through the lens of origami-based engineering. Novel architectures and behaviors of mechanisms are developed to achieve packaging efficiency, deployment, and self-stiffening. A method for the folding of monolithic thick-sheet materials is developed by incorporating compliant mechanisms into the material itself to strategically add degrees of freedom. The design and characterization of the compliant mechanisms with consideration to …
Joint Analysis Of And Applications For Devices With Expanding Motions, Kendall Hal Seymour
Joint Analysis Of And Applications For Devices With Expanding Motions, Kendall Hal Seymour
Theses and Dissertations
Origami has been extensively studied by engineers for its unique motions and ability to collapse to small volumes. Techniques have been studied for replicating origami-like folding motion in thick materials, but limited practical applications of these techniques have been demonstrated. Developable mechanisms are a new mechanism type that has a similar ability to collapse to a low profile. The cylindrical developable mechanism has the ability to emerge from and conform to a cylindrical surface. In this work, a few practical applications of devices with novel expanding motions are presented. The design and testing of an origami-inspired deployable ballistic barrier, which …
Developing New Classes Of Thick-Origami-Based Mechanisms: Conceal-And-Reveal Motion And Folding Printed Circuit Boards, Bryce Parker De Figueiredo
Developing New Classes Of Thick-Origami-Based Mechanisms: Conceal-And-Reveal Motion And Folding Printed Circuit Boards, Bryce Parker De Figueiredo
Theses and Dissertations
Origami-adapted mechanisms form the basis of an increasing number of engineered systems. As most of these systems require the use of non-paper materials, various methods for accommodating thickness have been developed. These methods have opened new avenues for origami-based design. This work introduces approaches for the design of two new classes of thick-origami systems and demonstrates the approaches in hardware. One type of system, called "conceal-and-reveal,'' is introduced, and a method of designing these mechanisms is developed. Techniques are also developed for designing folding printed circuit boards which are fabricated from a single sheet of material. This enables areas of …
Selecting Surrogate Folds For Use In Origami-Based Mechanisms And Products, Jason Tyler Allen
Selecting Surrogate Folds For Use In Origami-Based Mechanisms And Products, Jason Tyler Allen
Theses and Dissertations
Origami-based design is increasing in popularity as its benefits and advantages become better understood and explored. However, many opportunities still exist for the application of origami principles to engineered designs, especially in the use of non-paper, thick sheet materials. One specific area utilizing thick sheet materials that is especially promising is origami-based mechanisms that require electrical power transfer applications. Many of these opportunities can be met by the use of surrogate folds. This thesis provides methods and frameworks that can be used by engineers to efficiently select and design surrogate folds for use in origami-based mechanisms and products. Surrogate folds …
Stiffness Reduction Strategies For Additively Manufactured Compliant Mechanisms, Ezekiel G. Merriam
Stiffness Reduction Strategies For Additively Manufactured Compliant Mechanisms, Ezekiel G. Merriam
Theses and Dissertations
This work develops and examines design strategies for reducing the stiffness of 3D-printed compliant mechanisms. The three aspects of a flexure that determine its stiffness are well known: material, boundary conditions, and geometry. In a highly constrained design space however, flexure stiffness may remain unacceptably high even while arriving at the limits of design constraints. In this work, changes to geometry and boundary conditions are examined that lead to drastically reduced stiffness behavior without changing flexure thickness, width, or length. Changes to geometry can result in very complex mechanisms. However, 3D printing enables almost arbitrarily complex geometries. This dissertation presents …
A Compliant Mechanism-Based Variable-Stiffness Joint, Jacob Marc Robinson
A Compliant Mechanism-Based Variable-Stiffness Joint, Jacob Marc Robinson
Theses and Dissertations
A review of current variable-stiffness actuators reveals a need for more simple, cost effective, and lightweight designs that can be easily incorporated into a variety of human-interactive robot platforms. This thesis considers the potential use of compliant mechanisms to improve the performance of variable-stiffness actuators. The advantages and disadvantages of various concepts using compliant mechanisms are outlined, along with ideas for further exploration. A new variable-stiffness actuator that uses a compliant flexure as the elastic element has been modeled, built, and tested. This new design involves a variable stiffness joint that makes use of a novel variable transmission. A prototype …
Compliant Mechanisms For Deployable Space Systems, Shannon Alisa Zirbel
Compliant Mechanisms For Deployable Space Systems, Shannon Alisa Zirbel
Theses and Dissertations
The purpose of this research is to develop fundamentals of compliant mechanisms in deployable space systems. The scope was limited to creating methods for thick origami, developing compliant deployable solar arrays, and developing methods for stowing and deploying the arrays. The research on actuation methods was focused on a one-time deployment of the array. Concepts for both passive and active actuation were considered. The primary objective of this work was to develop approaches to accommodate thickness in origami-based deployable arrays with a high ratio of deployed-to-stowed diameter. The HanaFlex design was derived from the origami flasher model and is developed …
Compliant Joints Suitable For Use As Surrogate Folds, Isaac L. Delimont
Compliant Joints Suitable For Use As Surrogate Folds, Isaac L. Delimont
Theses and Dissertations
Origami-inspired design is an emerging field capable of producing compact and efficient designs. The object of a surrogate fold is to provide a fold-like motion in a non-paper material without undergoing yielding. Compliant mechanisms provide a means to achieve these objectives as large deflections are achieved. The purpose of this thesis is to present a summary of existing compliant joints suitable for use as surrogate folds. In doing so, motions are characterized which no existing compliant joint provides. A series of compliant joints is proposed which provides many of these motions. The possibility of patterning compliant joints to form an …
Articulated Spine For A Robot To Assist Children With Autism, Brandon M. Norton
Articulated Spine For A Robot To Assist Children With Autism, Brandon M. Norton
Theses and Dissertations
Autism spectrum disorder (ASD) affects about 1.5 million individuals in the US alone. The consequences of ASD affect families, caregivers, and social structures. This thesis adds to a growing group of people performing research on mitigating the effects of autism through robotics. Children with ASD tend to interact with robots more easily than with other humans. The goal of robotic therapy is not to help children interact with robots, but to generalize the behavior to humans. An articulated spine is a key to human emotional expression through shaping, weight shifting, and flow. Despite this importance, this feature is all but …
Origami-Based Design For Engineering Applications, Kevin Campbell Francis
Origami-Based Design For Engineering Applications, Kevin Campbell Francis
Theses and Dissertations
Origami can be a powerful source of design inspiration in the creation of reconfigurable systems with unparalleled performance. This thesis provides fundamental tools for designers to employ as origami-based designs are pursued in their respective fields of expertise. The first chapter introduces origami and makes connections between origami and engineering design through a survey of engineered applications and characterizing the relationship between origami and compliant mechanisms. The second chapter evaluates the creasing of non-paper sheet materials, such as plastics and metals, to facilitate origami-based compliant mechanism design. Although it is anticipated that most origami-based design will result from surrogate folds …
A Study Of Action Origami As Systems Of Spherical Mechanisms, Landen A. Bowen
A Study Of Action Origami As Systems Of Spherical Mechanisms, Landen A. Bowen
Theses and Dissertations
Origami, the Japanese art of paper folding, has been used previously to inspire engineering solutions for compact, deployable designs. Action origami, the subset of origami dealing with models designed to move, is a previously unexplored area for engineering design solutions that are deployable and have additional motion in the deployed state. A literature review of origami in engineering is performed, resulting in seven key areas of technical origami literature from a wide variety of disciplines. Spherical mechanisms are identified as the method by which most action origami models achieve complicated motion while remaining flat-foldable. The subset of action origami whose …
Fully Compliant Mechanisms For Bearing Subtraction In Robotics And Space Applications, Ezekiel G. Merriam
Fully Compliant Mechanisms For Bearing Subtraction In Robotics And Space Applications, Ezekiel G. Merriam
Theses and Dissertations
Robotics and space applications represent areas where compliant mechanisms can continue to make a significant impact by reducing costs and weight while improving performance. Because of the nature of these applications, a common need is for bearing replacement mechanisms, or mechanisms that perform the function of a bearing without the complexity and failure modes associated with bearings. Static balancing is a design strategy that attempts to reduce the actuation effort of a mechanism, and has been applied to compliant mechanisms in some applications. Monolithic construction, especially by means of 3D printing technology, is a strategy whereby the mechanism links and …
Investigation Of Compliant Space Mechanisms With Application To The Design Of A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler
Investigation Of Compliant Space Mechanisms With Application To The Design Of A Large-Displacement Monolithic Compliant Rotational Hinge, Robert Mcintyre Fowler
Theses and Dissertations
The purpose of this research is to investigate the use of compliant mechanisms in space applications and design, analyze, and test a compliant space mechanism. Current space mechanisms are already highly refined and it is unclear if significant improvements in performance can be made by continuing to refine current designs. Compliant mechanisms offer a promising opportunity to change the fundamental approach to achieving controlled motion in space systems and have potential for dramatic increases in mechanism performance given the constraints of the space environment. A compliant deployment hinge was selected for development after industry input was gathered. Concepts for large-displacement …
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Mechanical Properties And Mems Applications Of Carbon-Infiltrated Carbon Nanotube Forests, Walter C. Fazio
Theses and Dissertations
This work explores the use of carbon-infiltrated carbon nanotube (CI-CNT) forests as a material for fabricating compliant MEMS devices. The impacts of iron catalyst layer thickness and carbon infiltration time are examined. An iron layer of 7nm or 10nm with an infiltration time of 30 minutes produces CI-CNT best suited for compliant applications. Average maximum strains of 2% and 2.48% were observed for these parameters. The corresponding elastic moduli were 5.4 GPa and 4.1 GPa, respectively. A direct comparison of similar geometry suggested CI-CNT is 80% more flexible than single-crystal silicon. A torsional testing procedure provided an initial shear modulus …
Toward The Design Of A Statically Balanced Fully Compliant Joint For Use In Haptic Interfaces, Levi Clifford Leishman
Toward The Design Of A Statically Balanced Fully Compliant Joint For Use In Haptic Interfaces, Levi Clifford Leishman
Theses and Dissertations
Haptic interfaces are robotic force-feedback devices that give the user a sense of touch as they interact with virtual or remote environments. These interfaces act as input devices, mapping the 3-dimensional (3D) motions of the user's hand into 3D motions in a slave system or simulated virtual world. A major challenge in haptic interfaces is ensuring that the user's experience is a realistic depiction of the simulated environment. This requires the interface's design to be such that it does not hinder the user's ability to feel the forces present in the environment. This "transparency" is achieved by minimizing the device's …
Expanding Lamina Emergent Mechanism (Lem) Capabilities: Spherical Lems, Lem Joints, And Lem Applications, Samuel E. Wilding
Expanding Lamina Emergent Mechanism (Lem) Capabilities: Spherical Lems, Lem Joints, And Lem Applications, Samuel E. Wilding
Theses and Dissertations
Lamina Emergent Mechanisms (LEMs) are a class of compliant mechanisms that can be manufactured from sheet goods and possess motion out of the plane of fabrication. LEMs can be designed to perform sophisticated motions. This thesis expands LEM understanding and increases the ability to utilize them in applications by introducing the fundamentals of spherical LEMs, creating joints suitable for LEMs, and providing an example of a LEM application. In this thesis, the fundamentals of spherical LEMs are developed. This includes classification of all possible spherical 4R LEMs and a discussion of the motion characteristics of the various mechanisms. The motion …
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen
Theses and Dissertations
Lamina emergent mechanisms (LEMs) are a maturing technology that is prepared for commercial implementation into new products. LEMs are defined by three functional characteristics; they (1) are compliant, (2) are fabricated from planar materials, and (3) emerge from a flat initial state. Advantages, design challenges, and design tools are described for each of the functional characteristics. Opportunities for LEMs are discussed, namely disposable LEMs, novel arrays of LEMs, scaled LEMs, LEMs with surprising motion, shock absorbing LEMs, and deployable LEMs. Technology push product development processes were employed to select applications for LEMs. LEM technology was characterized. In a LEM workshop, …
Modeling, Design, And Testing Of Contact-Aided Compliant Mechanisms In Spinal Arthroplasty, Peter Andrew Halverson
Modeling, Design, And Testing Of Contact-Aided Compliant Mechanisms In Spinal Arthroplasty, Peter Andrew Halverson
Theses and Dissertations
Injury, instrumentation, or surgery may change the functional biomechanics of the spine. Spinal fusion, the current surgical treatment of choice, stabilizes the spine by rigid fixation, reducing spinal mobility at the cost of increased stress at adjacent levels. Recently, alternatives to spinal fusion have been investigated. One such alternative is total disc replacements. The current generation of total disc replacements (TDRs) focuses on restoring the quantity of motion. Recent studies indicate that the moment-rotation response and axis of rotation, or quality of motion (QOM), may have important implications in the health of adjacent segments as well as the health of …
A Design Framework That Employs A Classification Scheme And Library For Compliant Mechanism Design, Brian Mark Olsen
A Design Framework That Employs A Classification Scheme And Library For Compliant Mechanism Design, Brian Mark Olsen
Theses and Dissertations
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 …
Development Of Criteria For Lamina Emergent Mechanism Flexures With Specific Application To Metals, Devin Bradley Ferrell
Development Of Criteria For Lamina Emergent Mechanism Flexures With Specific Application To Metals, Devin Bradley Ferrell
Theses and Dissertations
This thesis introduces new revolute and torsional lamina emergent mechanism (LEM) flexure designs that are suited for use in metals. Previous LEM flexures have been designed for use in highly elastic materials, such as polymers. In extending LEM flexure designs to metals, a LEM flexure design criteria is also introduced. The LEM flexure criteria is based on relative performance between the LEM flexure and a performance datum which the LEM flexure must improve upon. This performance datum, or benchmark, is a section of lamina that is of the same overall length, width, and thickness as the LEM flexure. An analysis …
Off-Axis Stiffness And Piezroresistive Sensing In Large-Displacement Linear-Motion Microelectromechanical Systems, David G. Smith
Off-Axis Stiffness And Piezroresistive Sensing In Large-Displacement Linear-Motion Microelectromechanical Systems, David G. Smith
Theses and Dissertations
Proper positioning of Microelectromechanical Systems (MEMS) components influences the functionality of the device, especially in devices where the motion is in the range of hundreds of micrometers. There are two main obstacles to positioning: off-axis displacement, and position determination. This work studies four large-displacement devices, their axial and transverse stiffness, and piezoresistive response. Methods for improving the device characteristics are described. The folded-beam suspension, small X-Bob, large X-Bob and double X-Bob were characterized using non-dimensional metrics that measure the displacement with regard to the size of the device, and transverse stiffness with regard to axial stiffness. The stiffness in each …
Integrated Piezoresistive Sensing For Feedback Control Of Compliant Mems, Robert K. Messenger
Integrated Piezoresistive Sensing For Feedback Control Of Compliant Mems, Robert K. Messenger
Theses and Dissertations
Feedback control of MEMS devices has the potential to significantly improve device performance and reliability. One of the main obstacles to its broader use is the small number of on-chip sensing options available to MEMS designers. A method of using integrated piezoresistive sensing is proposed and demonstrated as another option. Integrated piezoresistive sensing utilizes the inherent piezoresistive property of polycrystalline silicon from which many MEMS devices are fabricated. As compliant MEMS structures flex to perform their functions, their resistance changes. That resistance change can be used to transduce the structures' deflection into an electrical signal. This dissertation addresses three topics …
Large-Displacement Linear-Motion Compliant Mechanisms, Allen B. Mackay
Large-Displacement Linear-Motion Compliant Mechanisms, Allen B. Mackay
Theses and Dissertations
Linear-motion compliant mechanisms have generally been developed for small displacement applications. The objective of the thesis is to provide a basis for improved large-displacement linear-motion compliant mechanisms (LLCMs). One of the challenges in developing large-displacement compliant mechanisms is the apparent performance tradeoff between displacement and off-axis stiffness. In order to facilitate the evaluation, comparison, and optimization of the performance of LLCMs, this work formulates and presents a set of metrics that evaluates displacement and off-axis stiffness. The metrics are non-dimensionalized and consist of the relevant characteristics that describe mechanism displacement, off-axis stiffness, actuation force, and size. Displacement is normalized by …
Multi-Stable Compliant Rolling-Contact Elements, Peter Andrew Halverson
Multi-Stable Compliant Rolling-Contact Elements, Peter Andrew Halverson
Theses and Dissertations
The purpose of this research is the development of design concepts and models of large-angle, compliant, multistable, revolute joints. This research presents evidence of the capability of these models and concepts by presenting a case study in which the miniaturization of revolute joints are examined. Previous attempts at multistable revolute joints can be categorized into two categories: compliant and non-compliant mechanisms. Non-compliant multistable revolute joints are typified by a combination of pin-in-slot joints, springs, and detents. Due to factors inherit in design, noncompliant joints often succumb to friction, wear, and undesirable motion, that leads to a decline in performance. Compliant …
The Piezoresistive Effect In Microflexures, Gary K. Johns
The Piezoresistive Effect In Microflexures, Gary K. Johns
Theses and Dissertations
The objective of this research is to present a new model for predicting the piezoresistive effect in microflexures experiencing bending stresses. A linear model describing piezoresistivity exists for members in pure tension and compression. Extensions of this model to more complex loading conditions do not match experimental results. An accurate model of piezoresistivity in complex loading conditions would expand the design possibilities of piezoresistive devices. A new model to predict piezoresistive effects in tension, compression, and more complex loading conditions is proposed. The focus of this research is to verify a unidirectional form of this proposed model for microflexures in …