Evolutionary robotics in high altitude wind energy applications

Recent years have seen the development of wind energy conversion systems that can exploit the superior wind resource that exists at altitudes above current wind turbine technology. One class of these systems incorporates a flying wing tethered to the ground which drives a winch at ground level. The wings often resemble sports kites, being composed of a combination of fabric and stiffening elements. Such wings are subject to load dependent deformation which makes them particularly difficult to model and control. Here we apply the techniques of evolutionary robotics i.e. evolution of neural network controllers using genetic algorithms, to the task of controlling a steerable kite. We introduce a multibody kite simulation that is used in an evolutionary process in which the kite is subject to deformation. We demonstrate how discrete time recurrent neural networks that are evolved to maximise line tension fly the kite in repeated looping trajectories similar to those seen using other methods. We show that these controllers are robust to limited environmental variation but show poor generalisation and occasional failure even after extended evolution. We show that continuous time recurrent neural networks (CTRNNs) can be evolved that are capable of flying appropriate repeated trajectories even when the length of the flying lines are changing. We also show that CTRNNs can be evolved that stabilise kites with a wide range of physical attributes at a given position in the sky, and systematically add noise to the simulated task in order to maximise the transferability of the behaviour to a real world system. We demonstrate how the difficulty of the task must be increased during the evolutionary process to deal with this extreme variability in small increments. We describe the development of a real world testing platform on which the evolved neurocontrollers can be tested

Technology for large space systems: A bibliography with indexes (supplement 22)

This bibliography lists 1077 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to the researcher or manager engaged in the development of technologies related to large space systems. Subject areas include mission and program definition, design techniques, structural and thermal analysis, structural dynamics and control systems, electronics, advanced materials, assembly concepts, and propulsion

Space station systems: A bibliography with indexes (supplement 10)

This bibliography lists 1,422 reports, articles, and other documents introduced into the NASA scientific and technical information system between July 1, 1989 and December 31, 1989. Its purpose is to provide helpful information to researchers, designers and managers engaged in Space Station technology development and mission design. Coverage includes documents that define major systems and subsystems related to structures and dynamic control, electronics and power supplies, propulsion, and payload integration. In addition, orbital construction methods, servicing and support requirements, procedures and operations, and missions for the current and future Space Station are included

Large space structures and systems in the space station era: A bibliography with indexes (supplement 03)

Bibliographies and abstracts are listed for 1221 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1991 and June 30, 1991. Topics covered include large space structures and systems, space stations, extravehicular activity, thermal environments and control, tethering, spacecraft power supplies, structural concepts and control systems, electronics, advanced materials, propulsion, policies and international cooperation, vibration and dynamic controls, robotics and remote operations, data and communication systems, electric power generation, space commercialization, orbital transfer, and human factors engineering

Design of Flight Control Laws for a Novel Stratospheric Dual-Aircraft Platform

Dual-aircraft platform (DAP) is a novel concept that features two glider-like unmanned aerial systems (UAS) tethered via a thin adjustable cable allowing them to sail back-and-forth, without propulsion, using vertical wind shear. DAP offers the potential of a low-cost atmospheric satellite. This thesis presents the results of an initiative to demonstrate this novel flight concept through modeling, simulation, and flight testing at Embry-Riddle Aeronautical University (ERAU). A realistic simulation environment, described herein, was developed to support the development and testing of flight control systems. This environment includes nonlinear aerodynamic models for the aircraft, a multi-element cable dynamics model, propeller-motor thrust model, control surface actuator models, and permits time-varying wind profiles. This simulator offers both pilot-in-the-loop control and autonomous sailing flight control, and X-Plane interface to provide visualization cues. An intensive flight test program, described herein, was conducted to support the validation of the DAP concept. MAXA Pro 4m gliders were assembled, instrumented, and flight tested in an effort to physically demonstrate the sailing mode of flight. The flight test program described here focuses on the capability to sail with one aircraft (i.e., fly without propulsion) while towing (i.e., pulling) a moving truck as an intermediate step towards the more complex scenario of sailing with two connected aircraft. Two vital elements of the flight software are implemented and analyzed herein. The accuracy of wind estimation techniques is evaluated using flight testing. The robustness of an L1 adaptive controller is evaluated within the flight simulation environment by comparing its performance with a conventional controller

Space Debris as an international safety issue. Case studies in active removing techniques.

Η παρούσα διπλωματική εργασία πραγματοποιήθηκε υπό την αιγίδα του Τμήματος Πληροφορικής & Τηλεπικοινωνιών του Εθνικού και Καποδιστριακού Πανεπιστημίου Αθηνών για το Μεταπτυχιακό Πρόγραμμα Σπουδών «Διαστημικές Τεχνολογίες, Εφαρμογές και Υπηρεσίες». Στόχος της διατριβής ήταν να αναδείξει τη σημασία της έγκαιρης ανάληψης δράσης σε διεθνές επίπεδο, ώστε το ζήτημα των διαστημικών υπολειμμάτων να μην γίνει μείζονα απειλή κατά των επιχειρησιακών διαστημικών συστημάτων και των ανθρώπων που βρίσκονται σε τροχιά γύρω από τη γη. Παρόλο που το θέμα των διαστημικών υπολειμμάτων έχει απασχολήσει τον επιστημονικό, τεχνολογικό και πολιτικό κόσμο σχεδόν από την απαρχή της διαστημικής εποχής, δεν έχει ακόμα βρεθεί ουσιαστική λύση ούτε σε επιστημονικό, ούτε σε τεχνολογικό, ούτε σε πολιτικό επίπεδο. Στα παρακάτω κεφάλαια γίνεται μια ανάλυση του προβλήματος των διαστημικών υπολειμμάτων και αναφέρονται τα τεχνολογικά, νομικά και οικονομικά εμπόδια που παρουσιάζονται σε μια προσπάθεια απομάκρυνσης διαστημικών υπολειμμάτων. Στη συνέχεια αναπτύσσεται η έννοια της ασφάλειας στο διάστημα και πώς αυτή επηρεάζεται από την ύπαρξη διαστημικών υπολειμμάτων. Ταυτόχρονα γίνεται μια ανάλυση του ρίσκου που διέπει τις διαστημικές αποστολές, τόσο σε επίπεδο συστημάτων, όσο και σε επίπεδο ανθρώπινης ζωής σε συνάρτηση με την αύξηση των διαστημικών υπολειμμάτων. Από την ανάλυση αυτή δεικνύεται ότι η αύξηση των διαστημικών υπολειμμάτων λόγω περισσότερων διαστημικών αποστολών, καθώς και το ξεκίνημα της εποχής του διαστημικού τουρισμού, θα αποτελέσει έναν ισχυρό παράγοντα κινδύνου εάν δεν παρθούν άμεσα μέτρα. Στη συνέχεια παρουσιάζονται, σε τεχνικό επίπεδο, οι δυνατότητες εντοπισμού και παρατήρησης των διαστημικών υπολειμμάτων, καθώς και οι προοπτικές αυτών των συστημάτων. Επιπλέον, γίνεται αναφορά στο ποιες θα είναι οι μελλοντικές απαιτήσεις εντοπισμού και παρατήρησης των διαστημικών υπολειμμάτων ώστε να είναι αποτελεσματικές οι αποστολές απομάκρυνσης διαστημικών υπολειμμάτων. Συνεχίζοντας, παρουσιάζονται οι κύριες τεχνικές ενεργητικής απομάκρυνσης διαστημικών υπολειμμάτων, όπως αυτές μελετώνται και κατασκευάζονται από διαστημικούς οργανισμούς και διαστημικές εταιρείες. Τέλος, διενεργείται μια συγκριτική μελέτη των τεχνικών απομάκρυνσης διαστημικών υπολειμμάτων μέσω βαθμολόγησης τεσσάρων κύριων κριτηρίων και παρουσιάζεται ως αποτέλεσμα μια υπόθεση βέλτιστης τεχνολογίας απομάκρυνσης διαστημικών υπολειμμάτων. Από τη ανάλυση της Διπλωματικής Εργασίας γίνεται αντιληπτή η σημαντικότητα του να ληφθούν άμεσα αποφάσεις και να γίνουν οι κατάλληλες ενέργειες, ώστε τα διαστημικά υπολείμματα να μην αποτελέσουν κύριο παράγοντα κινδύνου για την ανθρωπότητα όπως τη γνωρίζουμε σήμερα.This thesis was conducted under the umbrella of the Department of Informatics & Telecommunication of the National and Kapodistrian University of Athens for the Postgraduate Program “Space Technologies, Applications and Services”. The aim of the thesis was to highlight the significance of taking timely action in an international level, for the space debris issue not to become a major threat against the operational space systems and the humans orbiting earth. Although the issue of space debris has occupied the scientific, technological and political world almost since the beginning of the space era, no substantial solution has yet been found either at a scientific, technological or political level. The following chapters provide an analysis of the space debris problem and present the technological, legal, and financial barriers to an effort to remove space debris. Then, the concept of security in space and the way it is affected by the existence of space debris is developed. At the same time, an analysis of the risk that governs space missions, both at the level of operation of space systems and at the level of human life in relation to the increase in space debris, is conducted. This analysis shows that the increase in space debris due to more space missions, as well as the onset of the era of space tourism, will be a strong risk factor if immediate measures are not taken. Then, at a technical level, the possibilities of locating and tracking space debris are presented, as well as the prospects of these technical systems. In addition, the future requirements for space debris detection and tracking, for space debris removal missions to be effective, are presented. Additionally, the main active space debris removal techniques studied and developed by space agencies and space companies are presented. Finally, a comparative study of space debris removal techniques is conducted by scoring four main criteria and a hypothesis of an optimal space debris removal technology is presented as a result. The analysis of the thesis shows the importance of making immediate decisions and taking the appropriate actions so that space debris does not constitute a major risk factor for humanity as we know it today

Space station systems: A bibliography with indexes (supplement 9)

This bibliography lists 1,313 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1, 1989 and June 30, 1989. Its purpose is to provide helpful information to researchers, designers and managers engaged in Space Station technology development and mission design. Coverage includes documents that define major systems and subsystems related to structures and dynamic control, electronics and power supplies, propulsion, and payload integration. In addition, orbital construction methods, servicing and support requirements, procedures and operations, and missions for the current and future Space Station are included

Autonomous Vehicles

This edited volume, Autonomous Vehicles, is a collection of reviewed and relevant research chapters, offering a comprehensive overview of recent developments in the field of vehicle autonomy. The book comprises nine chapters authored by various researchers and edited by an expert active in the field of study. All chapters are complete in itself but united under a common research study topic. This publication aims to provide a thorough overview of the latest research efforts by international authors, open new possible research paths for further novel developments, and to inspire the younger generations into pursuing relevant academic studies and professional careers within the autonomous vehicle field

Birds, Bats and Minds. Tales of a Revolutionary Scientist: Donald R. Griffin. Volume Two

In this three-volume biography, we revisit the life and accomplishments of the revolutionary scientist, Donald R. Griffin. He encountered a lifetime of initial hostile resistance to his ideas and studies; now they are largely accepted. He and a colleague discovered the phenomenon of echolocation used by bats to navigate and capture insects, proposed that birds navigate guided by such cues as the sun and stars, and suggested that animals are likely aware, thinking and feeling beings. Forty interviews with his colleagues and friends help us understand the young emerging scientist and the mature researcher. We learn about his and others’ research up to the present times. We gain insights into his thinking and the rigors and delights of fieldwork. Efforts to promote animal well-being intrinsically depend upon the insights from his groundbreaking ideas. In Volume two, Griffin leaves the hostile environment at Harvard to accept an invitation to establish a new institute of animal behavior studies at the Rockefeller University (RU), and helps establish a field station. He entices the ornithologist Peter Marler to join him. During his studies of puzzling fishing bats at the tropical research station in Trinidad, Griffin meets and later marries the noted marine scientist Jocelyn Crane, who manages the station with famed naturalist William Beebe. Griffin pursues ground-breaking research with bats and, using radar tracking, of migrating birds across the sea. Detailed descriptions are provided of the findings regarding bats and their use of echolocating signals. The innovative work of numerous RU animal behavior researchers is described as is the harsh and strenuous work of field research and the thrill and joy in the scientists’ discoveries.https://www.wellbeingintlstudiesrepository.org/ebooks/1032/thumbnail.jp

Space, the new frontier

Space program - high thrust boosters with greater payload capabilities, superior guidance and control, and astronaut trainin