Monitoring bioinspired fibrillar grippers by contact observation and machine learning

The remarkable properties of bio-inspired microstructures make them extensively accessible for various applications, including industrial, medical, and space applications. However, their implementation especially as grippers for pick-and-place robotics can be compromised by multiple factors. The most common ones are alignment imperfections with the target object, unbalanced stress distribution, contamination, defects, and roughness at the gripping interface. In the present work, three different approaches to assess the contact phenomena between patterned structures and the target object are presented. First, in-situ observation and machine learning are combined to realize accurate real-time predictions of adhesion performance. The trained supervised learning models successfully predict the adhesion performance from the contact signature. Second, two newly developed optical systems are compared to observe the correct grasping of various target objects (rough or transparent) by looking through the microstructures. And last, model experiments are provided for a direct comparison with simulation efforts aiming at a prediction of the contact signature and an analysis of the rate and preload-dependency of the adhesion strength of a soft polymer film in contact with roughness-like surface topography. The results of this thesis open new perspectives for improving the reliability of handling systems using bioinspired microstructures.Durch die besonderen Eigenschaften bioinspirierter Mikrostrukturen können diese für verschiedene Anwendungen genutzt werden, einschließlich industrieller, medizinischer und Weltraumanwendungen. Ihre Implementierung, insbesondere als Greifer für Pick-and-Place-Robotiker, kann jedoch durch mehrere Faktoren beeinträchtigt werden. Am häufigsten sind Ausrichtungsmängel an das Zielobjekt, unausgeglichene Spannungsverteilungen, Defekte und Rauheit an der Greifschnittstelle. Die vorliegende Arbeit zeigt drei verschiedene Ansätze, um den Kontakt zwischen strukturierten Adhäsiven und Zielobjekten zu untersuchen. Zunächst werden in-situ Beobachtungen und maschinelles Lernen kombiniert, um Echtzeitvorhersagen der Adhäsionsleistung zu ermöglichen. Die trainierten Modelle werden verwendet, um die Haftungsleistung anhand der Kontaktsignatur des Pads erfolgreich zu prognostizieren. Anschließend werden zwei neu entwickelte, optische Systeme verglichen, mit denen das korrekte ” Greifen“ von verschiedenen Objekten (mit rauen oder undurchsichtigen Oberflächen) durch die Mikrostrukturen live verfolgt werden kann. Zuletzt werden Modellexperimente durchgeführt, die mit Simulationen der Signatur des Kontakts einer weichen Polymerschicht mit einer idealisierten rauen Gegenfläche direkt verglichen werden können. Die Ergebnisse dieser Arbeit eröffnen neue Perspektiven zur zuverlässigeren Verwendung von Handhabungssystemen mit bioinspirierten Mikrostrukturen.Leibniz Competition Grant MUSIGAND (No. K279/2019) awarded to Eduard Arz

Technology for the Future: In-Space Technology Experiments Program, part 2

The purpose of the Office of Aeronautics and Space Technology (OAST) In-Space Technology Experiments Program In-STEP 1988 Workshop was to identify and prioritize technologies that are critical for future national space programs and require validation in the space environment, and review current NASA (In-Reach) and industry/ university (Out-Reach) experiments. A prioritized list of the critical technology needs was developed for the following eight disciplines: structures; environmental effects; power systems and thermal management; fluid management and propulsion systems; automation and robotics; sensors and information systems; in-space systems; and humans in space. This is part two of two parts and contains the critical technology presentations for the eight theme elements and a summary listing of critical space technology needs for each theme

2020 NASA Technology Taxonomy

This document is an update (new photos used) of the PDF version of the 2020 NASA Technology Taxonomy that will be available to download on the OCT Public Website. The updated 2020 NASA Technology Taxonomy, or "technology dictionary", uses a technology discipline based approach that realigns like-technologies independent of their application within the NASA mission portfolio. This tool is meant to serve as a common technology discipline-based communication tool across the agency and with its partners in other government agencies, academia, industry, and across the world

Multiscale mechanics of bioinspired dry adhesives

The adhesive systems of climbing animals have served as inspiration for a new class of temporary adhesive utilizing surface microstructure in place of intrinsically soft and viscoelastic materials. These have the potential to address requirements for robust, releasable, and reusable bonding. Efforts to characterize synthetic dry adhesives, as well as to scale adhesive patches to large areas while maintaining performance, necessitate consideration of features of the system across length scales. This work addresses two topics which require that the behavior of individual microfibrils be accounted for explicitly within large-scale loading configurations.Under ideal conditions the strength of fibril arrays is known to be controlled by an array edge load concentration associated with compliance of the backing layer. Laboratory experiments have revealed that the strength is sensitive to the alignment of the adhesive and substrate surfaces, however no systematic investigation of the response to these perturbations in the loading configuration has been performed. A contact mechanics model is developed, considering the role of backing layer compliance in addition to misalignment. A monotonic decay in the adhesive strength of the array with increasing misalignment angle is confirmed. More interestingly, regimes of dominance of backing layer compliance and misalignment in control of the adhesive strength are revealed. Where circumferential detachment gives way to peel-like detachment, compliance of the backing layer is found to be beneficial to performance. This is the result of shielding of the peel-front load concentration by backing layer deformation. Subsequent experimental characterization of a mushroom-tipped synthetic fibril array shows that this regime is dominant for misalignment angles of just ~ 0.2° over a patch size of 2 mm. These results can be utilized to anticipate the performance of fibrillar adhesive patches on flat surfaces without precise control of alignment, or of sub-arrays within a larger hierarchy where surface undulations may lead to local misalignment.While the potential importance of the variability in fibril adhesive strength in controlling the performance of microstructure arrays has been highlighted in past work, there has been no effort to systematically characterize the strength distribution or understand its effect on performance further. The capabilities of an experimental platform with in-situ contact visualization are leveraged to provide strength data on a fibril-by-fibril basis. A framework is developed, based upon the statistical theory of fracture, allowing for the decoupling of two defect populations and assessment of the impact of fabrication imperfections on performance. A subsequent theoretical investigation is performed with a view to understanding the combined effect of variability in fibril adhesive strength and load concentrations at the array scale. It is shown that, dependent on the severity of the load concentration, increased variability in fibril adhesive strength can modulate the influence of load concentrations and lead to independence of the adhesive strength of the array from properties such as backing layer compliance or substrate curvature. This is highly significant, given that the severity of load concentrations is a key factor in designing hierarchical structures for adhesive strength

Cumulative index to NASA Tech Briefs, 1963-1967

Cumulative index to NASA survey on technology utilization of aerospace research outpu

Technology 2000, volume 1

The purpose of the conference was to increase awareness of existing NASA developed technologies that are available for immediate use in the development of new products and processes, and to lay the groundwork for the effective utilization of emerging technologies. There were sessions on the following: Computer technology and software engineering; Human factors engineering and life sciences; Information and data management; Material sciences; Manufacturing and fabrication technology; Power, energy, and control systems; Robotics; Sensors and measurement technology; Artificial intelligence; Environmental technology; Optics and communications; and Superconductivity

The 24th Aerospace Mechanisms Symposium

The proceedings of the symposium are reported. Technological areas covered include actuators, aerospace mechanism applications for ground support equipment, lubricants, latches, connectors, and other mechanisms for large space structures

Fifth Annual Workshop on Space Operations Applications and Research (SOAR 1991), volume 2

Papers given at the Space Operations and Applications Symposium, host by the NASA Johnson Space Center on July 9-11, 1991 are given. The technical areas covered included intelligent systems, automation and robotics, human factors and life sciences, and environmental interactions

Architecture's Model Environments

Seen through the distilling lens of the architectural model, Architecture’s Model Environments is a novel and far-reaching exploration of the many dialogues buildings have with their environmental surroundings. Expanding on histories of building technology, the book sheds new light on how physical models conventionally understood as engineering experimentation devices enable architectural design speculation. The book begins with a catalogue of ten original model prototypes – of wind tunnels, water tables and filling boxes – and is the first of its kind to establish an architectural approach to fabricating such environmental models. Subsequent chapters feature three precedent models that have been largely overlooked within the wider oeuvres of their authors: French polymath Étienne-Jules Marey’s 1900-2 wind tunnels, Hungarian-American architects Victor and Aladár Olgyay’s 1955-63 thermoheliodon, and Scottish chemist and building ventilation expert David Boswell ‘The Ventilator’ Reid’s 1844 test tube convection experiments. Moving between historic moments and the present day, between case studies and original prototypes, the book reveals the potent ability for models, as both physical artefacts and mental ideals, to reflect prevailing cultural views about the world and to even reshape those views. Fundamentally, Architecture’s Model Environments illustrates how environmental models reveal design insights across scales from the seam (that leaks) to the body (that feels) to the building (that mediates) to the world (that immerses)