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

Robotic Swing Folding of three-dimensional UD-tape-based Reinforcement Structures

Hybridbauteile aus Langfaserverstärktem Thermoplast (LFT) und unidirektional endlosfaserverstärkten (UD-) Tapes bieten die Möglichkeit zur Gewichtseinsparung bei geringeren Fertigungskosten gegenüber reinen UD-Tape-Bauteilen. In hybriden Bauteilen wird die einfache Verarbeitung des LFT genutzt um Ecken, Rippen und weitere geometrisch anspruchsvolle Bauteilbereiche zu füllen, während Steifigkeit und Festigkeit durch das UD-Tape erhöht werden. Das Preforming ist der aufwändigste Schritt in der Verarbeitung des endlosfaserverstärkten UD-Tapes. Um die Wirtschaftlichkeit hybrider Bauteile zu erhöhen, muss dieser Aufwand minimiert werden. Bisherige Prozesse für das Preforming sind nicht an die Anforderungen von Verstärkungsstrukturen in hybriden Bauteilen angepasst und benötigen daher zusätzliche Handhabungsschritte um das Material bereit zu stellen, und teure, bauteilspezifische Werkzeuge, um das Material zu formen. Gleichzeitig bieten sie große Möglichkeiten bei der Bauteilkomplexität die nicht benötigt werden, da komplizierte Bauteilregionen in hybriden Bauteilen durch LFT abgebildet werden können. In dieser Arbeit wird ein Prozess für das flexible Preforming linearer Verstärkungsstrukturen aus UD-Tape-Streifen entwickelt, in Betrieb genommen und optimiert. Zusätzlich wird ein Algorithmus vorgestellt, mit dem die Preformgeometrie an die Prozessrestriktionen angepasst wird. Durch den neuen Prozess können Kosten für bauteilspezifische Preformwerkzeuge vermieden werden und Abweichungen in folgenden Prozessschritten können in der laufenden Produktion bei folgenden Werkstücken kompensiert werden

NASA Tech Briefs, December 1989

Topics include: Electronic Components and Circuits. Electronic Systems, Physical Sciences, Materials, Computer Programs, Mechanics, Machinery, Fabrication Technology, Mathematics and Information Sciences, and Life Sciences

Quality Diversity: Harnessing Evolution to Generate a Diversity of High-Performing Solutions

Evolution in nature has designed countless solutions to innumerable interconnected problems, giving birth to the impressive array of complex modern life observed today. Inspired by this success, the practice of evolutionary computation (EC) abstracts evolution artificially as a search operator to find solutions to problems of interest primarily through the adaptive mechanism of survival of the fittest, where stronger candidates are pursued at the expense of weaker ones until a solution of satisfying quality emerges. At the same time, research in open-ended evolution (OEE) draws different lessons from nature, seeking to identify and recreate processes that lead to the type of perpetual innovation and indefinitely increasing complexity observed in natural evolution. New algorithms in EC such as MAP-Elites and Novelty Search with Local Competition harness the toolkit of evolution for a related purpose: finding as many types of good solutions as possible (rather than merely the single best solution). With the field in its infancy, no empirical studies previously existed comparing these so-called quality diversity (QD) algorithms. This dissertation (1) contains the first extensive and methodical effort to compare different approaches to QD (including both existing published approaches as well as some new methods presented for the first time here) and to understand how they operate to help inform better approaches in the future. It also (2) introduces a new technique for encoding neural networks for evolution with indirect encoding that contain multiple sensory or output modalities. Further, it (3) explores the idea that QD can act as an engine of open-ended discovery by introducing an expressive platform called Voxelbuild where QD algorithms continually evolve robots that stack blocks in new ways. A culminating experiment (4) is presented that investigates evolution in Voxelbuild over a very long timescale. This research thus stands to advance the OEE community\u27s desire to create and understand open-ended systems while also laying the groundwork for QD to realize its potential within EC as a means to automatically generate an endless progression of new content in real-world applications

A data driven approach in less expensive robust transmitting coverage and power optimization

This paper aims the development of a new reduced-cost algorithm for a multi-objective robust transmitter placement under uncertainty. Toward this end, we propose a new hybrid Kriging/Grey Wolf Optimizer (GWO) approach combined with robust design optimization to estimate the set of Pareto frontier by searching robustness as well as accuracy (lower objective function) in a design space. We consider minimization of the energy power consumption for transmitting as well as maximization of signal coverage in a multi-objective robust optimization model. The reliability of the model to control signal overlap for multiple transmitting antennas is also provided. To smooth computational cost, the proposed method instead of evaluating all receiver test points in each optimization iteration approximates signal coverages using Kriging interpolation to obtain optimal transmitter positions. The results demonstrate the utility and the efficiency of the proposed method in rendering the robust optimal design and analyzing the sensitivity of the transmitter placement problem under practically less-expensive computational efforts (350% and 320% less than computational time elapsed using standalone GWO and NSGAII respectively)

Thermo-hydro-mechanical simulation of a generic geological disposal facility for radioactive waste

Geological disposal is required for the safe and long-term disposal of legacy radioactive waste. High level waste and spent fuel generate significant heat that will cause thermo-hydro-mechanical coupled processes in the rock mass. The thermal expansion of the fluid will be greater than the grains causing a decrease in mean effective stress with the low permeability restricting Darcy flow and excess pore pressure equilibration. A decrease in mean effective stress can reduce material strength in granular materials, which may be significant near excavations where differential stress is increased. Microseismic monitoring provides cost effective, non-intrusive and three-dimensional data that can be calibrated with the stress and strain behaviour of a rock mass. However, there is no precedent for the microseismic monitoring of heat-producing radioactive waste. Generic concepts, analogue materials and data from in situ experiments are used to demonstrate the potential for the microseismic monitoring of heat-producing radioactive waste in lower strength sedimentary rocks. A mechanism for early post-closure microseismicity is demonstrated, whereby excess pore pressure decreases the mean effective stress towards yielding in shear. The rock and fluid property uncertainties are ranked according to their contribution to the excess pore pressure. Permeability is found to be important as expected, however, Biot's coefficient is demonstrably more important and yet often overlooked. Furthermore, the microseismic event locations, timings and pseudo scalar seismic moments are shown to have statistically significant relationships with the engineered backfill swelling pressure. Therefore, early post-emplacement microseismic monitoring could provide constraints for the engineered backfill swelling pressure and rock property uncertainties whilst the facility is still operational. Insights could prove timely for adapting the engineering designs, if they are not behaving as expected, in further high level waste and spent fuel tunnels

Formability of Polymer-coated Metals

This project was undertaken to explore the viability of manufacturing polymer-coated cans using current drawing-wall-ironing methods, and centres around exploring polymer-coated alternatives to lacquered food and beverage cans. A full process FEA model was developed in Abaqus, and a polymer coating characterisation was attempted via tensile and compressive tests of available PET. As an alternative, the polymer was modelled as a force/over-closure con-tact definition in finite element analysis models, using force data derived from existing polymer data. The contact definition demonstrated an effective alter-native to modelling a finite element meshed polymer layer but needed opti-mising to match physical results. A tensile test machine rig was designed and manufactured capable of ironing strip metal specimens for otherwise unavail-able ironing metrology. The rig was calibrated using uncoated steel, then used to gain data on force and resulting geometry for polymer coated steel during and after ironing. Rig data was used in a finite element analysis automated feedback loop to optimise the force/over-closure and friction coefficients for the contact definition. Finally, a full-process drawing-wall-ironing simulation on polymer coated steel was implemented in a design of experiments study, which mapped the previously unexplored design space. The most significant parameters in resulting can geometry were the percentage of redraw and iron-ing during the respective forming phases, as well as the redraw radius. De-creasing the diameter of both redraw and ironing tooling rings resulted in a longer and thinner can, as did decreasing the redraw radius. Whilst not an ex-haustive study, the project ultimately demonstrated the viability of modelling polymer-coatings using contact definitions in finite element analysis and paves the way for further study into the polymer-coated steel can

Physical and statistical shape modelling in craniomaxillofacial surgery: a personalised approach for outcome prediction

Orthognathic surgery involves repositioning of the jaw bones to restore face function and shape for patients who require an operation as a result of a syndrome, due to growth disturbances in childhood or after trauma. As part of the preoperative assessment, three-dimensional medical imaging and computer-assisted surgical planning help to improve outcomes, and save time and cost. Computer-assisted surgical planning involves visualisation and manipulation of the patient anatomy and can be used to aid objective diagnosis, patient communication, outcome evaluation, and surgical simulation. Despite the benefits, the adoption of three-dimensional tools has remained limited beyond specialised hospitals and traditional two-dimensional cephalometric analysis is still the gold standard. This thesis presents a multidisciplinary approach to innovative surgical simulation involving clinical patient data, medical image analysis, engineering principles, and state-of-the-art machine learning and computer vision algorithms. Two novel three-dimensional computational models were developed to overcome the limitations of current computer-assisted surgical planning tools. First, a physical modelling approach – based on a probabilistic finite element model – provided patient-specific simulations and, through training and validation, population-specific parameters. The probabilistic model was equally accurate compared to two commercial programs whilst giving additional information regarding uncertainties relating to the material properties and the mismatch in bone position between planning and surgery. Second, a statistical modelling approach was developed that presents a paradigm shift in its modelling formulation and use. Specifically, a 3D morphable model was constructed from 5,000 non-patient and orthognathic patient faces for fully-automated diagnosis and surgical planning. Contrary to traditional physical models that are limited to a finite number of tests, the statistical model employs machine learning algorithms to provide the surgeon with a goal-driven patient-specific surgical plan. The findings in this thesis provide markers for future translational research and may accelerate the adoption of the next generation surgical planning tools to further supplement the clinical decision-making process and ultimately to improve patients’ quality of life

END OF LIFE MANAGEMENT OF ELECTRONIC WASTE

Electronic products are becoming obsolete at a very high rate due to rapid changes in consumer demand and technological advancements. However, on other hand End-of-Life (EOL) management of electronic products is not effectively approached while these products offer huge opportunities for effective recycling. In this context, this thesis has highlighted the current practices and issues related to EOL management of electronic products focusing on their different material compositions, the uses of their raw materials in the circular economy perspective. The thesis proposes the introduction of digital technologies into the recycling process to improve efficiency. More specifically, this thesis has focused on the corona electrostatic separation process and the improvement of efficiency based on the simulation of the particle trajectories to identify the most effective parameters. Thus, in this frame, a numerical model to predict the particle trajectories in a corona electrostatic separator is developed using COMSOL Multiphysics and MATLAB software and validated with experimental trials. The recycling of electronic waste is becoming challenging due to its diverse and constantly changing material composition. In this regard, this thesis illustrates the use of non-destructive visible near-infrared hyperspectral imaging (VNIR-HSI) technique to identify material accurately; the effectiveness of VNIR-HSI is demonstrated through an experimental campaign combined with machine learning models, such as Support Vector Machine, K-Nearest Neighbors and Neural Network.Nonostante i prodotti elettronici diventino obsoleti ad un ritmo molto elevato, a causa dei rapidi cambiamenti nella domanda dei consumatori e dei progressi tecnologici, la gestione del loro fine vita (End-of-Life (EOL)) non viene affrontata in modo efficace benché offra, invece, grandi opportunità di riciclo. In questo contesto, questa tesi ha evidenziato le attuali pratiche e problematiche relative alla gestione del fine vita dei prodotti elettronici concentrandosi sulla loro diversa composizione, l’utilizzo delle materie prime seconde ricavabili in una prospettiva di economia circolare. La tesi propone l’introduzione di tecnologie digitali nel processo di riciclo per migliorarne l'efficienza. In particolare, questa tesi si è concentrata sul processo di separazione elettrostatica a corona e sul miglioramento dell'efficienza grazie alla simulazione delle traiettorie delle particelle per identificare i parametri più efficaci. Pertanto, in questo studio, utilizzando i software COMSOL Multiphysics e MATLAB, è stato sviluppato un modello numerico per prevedere le traiettorie delle particelle in un separatore elettrostatico a corona; il modello è stato poi validato con prove sperimentali. Il riciclo dei rifiuti elettronici sta diventando sempre più complesso a causa della presenza di mix di materiali diversificati e in continua evoluzione. A questo proposito, la tecnologia di visione iperspettrale non distruttiva basata su lunghezze d’onda nel visibile e nel vicino infrarosso (VNIR-HSI) è stata utilizzata in questo lavoro di tesi per identificare il materiale in modo preciso; l'efficacia di VNIR-HSI, combinato con modelli di apprendimento automatico, come la Support Vector Machine, K-Nearest Neighbors e Neural Network, viene dimostrata attraverso una campagna sperimentale

Grasp plannind under task-specific contact constraints

Several aspects have to be addressed before realizing the dream of a robotic hand-arm system with human-like capabilities, ranging from the consolidation of a proper mechatronic design, to the development of precise, lightweight sensors and actuators, to the efficient planning and control of the articular forces and motions required for interaction with the environment. This thesis provides solution algorithms for a main problem within the latter aspect, known as the {\em grasp planning} problem: Given a robotic system formed by a multifinger hand attached to an arm, and an object to be grasped, both with a known geometry and location in 3-space, determine how the hand-arm system should be moved without colliding with itself or with the environment, in order to firmly grasp the object in a suitable way. Central to our algorithms is the explicit consideration of a given set of hand-object contact constraints to be satisfied in the final grasp configuration, imposed by the particular manipulation task to be performed with the object. This is a distinguishing feature from other grasp planning algorithms given in the literature, where a means of ensuring precise hand-object contact locations in the resulting grasp is usually not provided. These conventional algorithms are fast, and nicely suited for planning grasps for pick-an-place operations with the object, but not for planning grasps required for a specific manipulation of the object, like those necessary for holding a pen, a pair of scissors, or a jeweler's screwdriver, for instance, when writing, cutting a paper, or turning a screw, respectively. To be able to generate such highly-selective grasps, we assume that a number of surface regions on the hand are to be placed in contact with a number of corresponding regions on the object, and enforce the fulfilment of such constraints on the obtained solutions from the very beginning, in addition to the usual constraints of grasp restrainability, manipulability and collision avoidance. The proposed algorithms can be applied to robotic hands of arbitrary structure, possibly considering compliance in the joints and the contacts if desired, and they can accommodate general patch-patch contact constraints, instead of more restrictive contact types occasionally considered in the literature. It is worth noting, also, that while common force-closure or manipulability indices are used to asses the quality of grasps, no particular assumption is made on the mathematical properties of the quality index to be used, so that any quality criterion can be accommodated in principle. The algorithms have been tested and validated on numerous situations involving real mechanical hands and typical objects, and find applications in classical or emerging contexts like service robotics, telemedicine, space exploration, prosthetics, manipulation in hazardous environments, or human-robot interaction in general