Origami has served as the inspiration for a number of engineered systems. In most cases, they require nonpaper materials where material thickness is non-negligible. Foldable mechanisms based on origami-like forms present special challenges for preserving kinematics and assuring non-self-intersection when the thickness of the panels must be accommodated. Several design approaches for constructing thick origami mechanisms by beginning with a zero-thickness origami pattern and transforming it into a rigidly foldable mechanism with thick panels are reviewed. The review includes existing approaches and introduces new hybrid approaches. The approaches are compared and contrasted and their manufacturability analyzed.
Compliant bistable mechanisms are monolithic devices with two stable equilibrium positions separated by an unstable equilibrium position. They show promise in space applications as nonexplosive release mechanisms in deployment systems, thereby eliminating friction and improving the reliability and precision of those mechanical devices. This paper presents both analytical and numerical models that are used to predict bistable behavior and can be used to create bistable mechanisms in materials not previously feasible for compliant mechanisms. Materials compatible with space applications are evaluated for use as bistable mechanisms and prototypes are fabricated in three different materials. Pin-puller and cutter release mechanisms are proposed as potential space applications.
A fully compliant constant-force mechanism that uses an initially angled parallelguiding mechanism is proposed. A pseudo-rigid-body model (PRBM) of the mechanism is developed and validated using both finite element models and experimental prototype testing. The PRBM is used as a preliminary design tool to identify parameters that result in a constant-force mechanism. An adjustable version of the mechanism is also proposed and is used to assess the range of validity of the PRBM and highlights how the system response can be varied by changing the flexible beams inclination. A finite element based optimization is used to create a modified version of the mechanism that incorporates beam-end rotation effects and offers greater performance. Potential applications for the mechanism are discussed and it is demonstrated as a component of a statically balanced system. 10 for constant-force mechanisms range from devices such as snap fits [12], to microelectromechanical systems [13, 14]. Early constant-force mechanisms were constant-force tension springs which are also known as Negator springs [15]. These springs consist of a strip of spring steel in a tightly wound coil and are found in consumer items such as tape 15 measures and pull-starts. Nathan proposed a rigid link constant-force generator
The use of origami-based bellows is of interest in fields where traditional metal bellows are incapable of meeting compression, mass, or flexibility constraints. Metal bellows are often used in space applications but frequently complicate spacecraft design. Origami-based bellows capable of meeting design constraints while adequately shielding sensitive spacecraft parts may be advantageous to space mechanism design. The design and testing of a highly compressible origami bellows for harsh environments is described. Several origami patterns were evaluated and the Kresling fold pattern was designed to meet constraints and selected for use in the bellows design. Origami bellows were prototyped in five different materials and tested in fatigue, thermal cycling, ablation, and radiation. Tested bellows show good fatigue life exceeding 100,000 cycles for some materials and resilience to potential harsh environmental conditions such as thermal cycling, abrasion, and high radiation. The bellows can be designed to fit within a given inner and outer diameter and stroke length depending on the design requirements. The origami bellows shows promise for space application and as an adequate replacement for current metal bellows due to its high compressibility and low mass.The design, testing, and fabrication of an origami-based bellows for microgravity drilling is presented. The benefits of origami created an opportunity for application on NASA's Asteroid Redirect Mission (ARM) to protect sensitive parts from debris. Origami-based bellows were designed to fit spacial limitations and meet needed compression ratios. Designs have demonstrated high mass reductions, improved stroke length, greatly decreased stowed volume, improved flexibility, and reduced reaction forces in comparison with traditional metal bellows. Material and design testing demonstrated that a nylon-reinforced polyvinyl fluoride based bellows with an aramid fiber stitched seam is well suited for debris containment in space conditions. Various epoxies were able to maintain an adequate bond with polyvinyl fluoride below expected environmental temperature for bellows mounting to the ARM drill. Asymmetric compression of the bellows can occur at extreme low temperatures and is preventable by balancing stiffness within the structure. ACKNOWLEDGMENTS First and foremost, I would like to thank my wife Amy for her support during this research, including motivation, editing, revisions, and organization. I thank my children Adelyn and Bridger for being excited about "daddy's space work." This work was made possible through foresight and trust offered to a then middle school teacher from Larry Howell and Spencer Magleby. I thank them for providing funding to pursue this work and obtain graduate credentials. I thank my mentor from NASA's Jet Propulsion Laboratory Aaron Parness for the opportunity to mature this work for space applications and for his guidance and professional advice. Additionally, I thank Brian Jensen for him mentoring. I could not have accomplished this work w...
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