Small unmanned aircraft Beard, Randal W; Beard, Randal W; McLain, Timothy W
2012., 20120226, 2012, 2012-02-26
eBook
Autonomous unmanned air vehicles (UAVs) are critical to current and future military, civil, and commercial operations. Despite their importance, no previous textbook has accessibly introduced UAVs to ...students in the engineering, computer, and science disciplines--until now. Small Unmanned Aircraft provides a concise but comprehensive description of the key concepts and technologies underlying the dynamics, control, and guidance of fixed-wing unmanned aircraft, and enables all students with an introductory-level background in controls or robotics to enter this exciting and important area.
Worldwide demand for robotic aircraft such as unmanned aerial vehicles (UAVs) and micro aerial vehicles (MAVs) is surging. Not only military but especially civil applications are being developed at a ...rapid pace. Unmanned vehicles offer major advantages when used for aerial surveillance, reconnaissance, and inspection in complex and inhospitable environments. UAVs are better suited for dirty or dangerous missions than manned aircraft and are more cost-effective. UAVs can operate in contaminated environments, for example, and at altitudes both lower and higher than those typically traversed by manned aircraft. Many technological, economic, and political factors have encouraged the development and operation of UAVs. New sensors, microprocessors, and propulsion systems are smaller, lighter, and more capable, leading to levels of endurance, efficiency, and autonomy that exceed human capacities. Comprising the latest research, this book describes step by step the development of small or miniature unmanned aerial vehicles and discusses in detail the integrated prototypes developed at the robotics laboratory of Chiba University. With demonstration videos, the book will interest not only graduate students, scientists, and engineers but also newcomers to the field.
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Unmanned aerial vehicles (UAV) have emerged as flexible, swift, and economical imaging systems that have proven their feasibility in urban infrastructure mapping. However, data derived from such ...systems are not utilized thoroughly. In this study, an object-oriented, multiresolution segmentation-based workflow is explored to automatically extract the urban features such as buildings and roads that can revolutionize the pace of existing mapping methods. This paper contemplates the automatic object-oriented-based feature extraction process on 5-cm true color ortho-rectified images and digital surface model (DSM). The data was generated using the JOUAV/CW-10 model and a Sony Camera with a 40-megapixel resolution. The segmentation procedure was implemented, defining various parameters such as scale, shape, and compactness. Here, the optimum scale, shape, and compactness parameters chosen for buildings and road segmentation are 100, 0.6, and 0.8, and 50, 0.5, and 0.9, respectively. The object-based image analysis (OBIA) results were compared to manually digitized features to assess the accuracy of the automated process. The fractal border error accuracy is calculated for urban features such as roads and buildings. The OBIA results indicated that completeness, correctness, and quality of building features were 98.2%, 97.6%, and 95.9%, respectively. Similarly, the road features' average completeness, correctness, and quality were 85.8%, 73.8%, and 68.2%, respectively, which is on the lower side due to obscuring of roads by the avenue trees. The methodology yielded promising results for urban feature extraction with substantial accuracy and can be implemented in other areas with little fine-tuning of feature extraction parameters.
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More so than in the past, the US is now embracing the logic of preventive force: using military force to counter potential threats around the globe before they have fully materialized. While popular ...with individuals who seek to avoid too many "boots on the ground," preventive force is controversial because of its potential for unnecessary collateral damage. Who decides what threats are 'imminent'? Is there an international legal basis to kill or harm individuals who have a connection to that threat? Do the benefits of preventive force justify the costs? And, perhaps most importantly, is the US setting a dangerous international precedent?
InPreventive Force, editors Kerstin Fisk and Jennifer Ramos bring together legal scholars, political scientists, international relations scholars, and prominent defense specialists to examine these questions, whether in the context of full-scale preventive war or preventive drone strikes. In particular, the volume highlights preventive drones strikes, as they mark a complete transformation of how the US understands international norms regarding the use of force, and could potentially lead to a 'slippery slope' for the US and other nations in terms of engaging in preventive warfare as a matter of course. A comprehensive resource that speaks to the contours of preventive force as a security strategy as well as to the practical, legal, and ethical considerations of its implementation,Preventive Forceis a useful guide for political scientists, international relations scholars, and policymakers who seek a thorough and current overview of this essential topic.
This paper presents the flight test verification and validation of a novel multi-reference longitudinal and lateral -directional guidance logic across multiple autonomous aircraft with distinctly ...different dynamics. L.sub.N guidance logic takes advantage of tracking a span of multiple references across the desired track, similar to an insect's compound eyes, allowing for a much higher temporal resolution and more predictive and anticipatory guidance logic. The stability of L.sub.N guidance algorithms is investigated using global Lyapunov stability theorems and its stability is proved. Validation and verification flight tests of L.sub.N lateral-directional guidance logic demonstrate superior tracking performance adaptability of this novel method compared to other methods such as L.sub.1 or L.sub.2.sup.+. The L.sub.N longitudinal guidance is newly developed in this paper and shows excellent altitude tracking capabilities and similarly scalable. Statistical analysis of multiple flight tests involving varying environmental states with three unique aircraft and different advanced flight controllers are shown to prove the capabilities, robustness, and consistency of L.sub.N guidance. Keywords UAS * Flight test * Autonomy * 3D guidance * Predictive and adaptive guidance * UAM * Lyapunov
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