A real-time computer algorithm to control and optimize aircraft flight profiles is described and applied to a three-dimensional minimum-time intercept mission. The proposed scheme has roots in two well-known techniques: singular perturbations and neighboring-optimal guidance. Use of singular-perturbation ideas is made in terms of the assumed trajectory-family structure. A heading/energy family of prestored point-mass-model state-Euler solutions is used as the baseline in this scheme. The next step is to generate a near-optimal guidance law that will transfer the aircraft to the vicinity of this reference family. The control commands fed to the autopilot consist of the reference controls plus correction terms which are linear combinations of the altitude and path-angle deviations from reference values, weighted by a set of precalculated gains. In this respect the proposed scheme resembles neighboring-optimal guidance. However, in contrast to the neighboring-optimal guidance scheme, the reference control and state variables as well as the feedback gains are stored as functions of energy and heading in the present approach. A detailed description of the feedback laws and of some of the mathematical tools used to construct the controller is presented. The construction of the feedback laws requires a substantial preflight computational effort, but the computation times for on-board execution of the feedback laws are very modest. Other issues relating to practical implementation are addressed as well. Numerical examples, comparing open-loop optimal and approximate feedback solutions for a sample high-performance fighter, illustrate the attractiveness of the guidance scheme. Optimal three-dimensional flight in the presence of a terrain limit is studied in some detail. / Ph. D. / incomplete_metadata

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Includes bibliographical references. / M.S.

Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Includes bibliographical references. / M.S.

Thesis. 1976. M.S. cn--Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO. / Includes bibliographical references. / M.S.cn

Path-following is a primary task for most marine, air or space crafts, especially during autonomous operations. Research on autonomous underwater vehicles (AUV) has received large interests in the last few decades with research incentives emerging from the safe, cost-effective and practical solutions provided by their applications such as search and rescue, inspection and monitoring of pipe-lines ans sub-sea structures. This thesis presents a novel guidance system based on the popular line-of-sight (LOS) guidance law for path-following (PF) of underwater vehicles (UVs) subject to environmental disturbances. Mathematical modeling and dynamics of (UVs) is presented first. This is followed by a comprehensive literature review on guidance-based path-following control of marine vehicles, which includes revised definitions of the track-errors and more detailed illustrations of the general PF problem. A number of advances on relative equations of motion are made, which include an improved understanding of the fluid FLOW frame and expression of its motion states, an analytic method of modeling the signs of forces and moments and the proofs of passivity and boundedness of relative UV systems in 3-D. The revision in the relative equations of motion include the concept of state relativity, which is an improved understanding of relativity of motion states expressed in reference frames and is also useful in incorporating environmental disturbances. In addition, the concept of drift rate is introduced along with a revision on the angles of motion in 3-D. A switching mechanism was developed to overcome a drawback of a LOS guidance law, and the linear and nonlinear stability results of the LOS guidance laws have been provided, where distinctions are made between straight and curved PF cases. The guidance system employs the unique formulation and solution of the speed allocation problem of allocating a desired speed vector into x and y components, and the course control that employs the slip angle for desired heading for disturbance rejection. The guidance system and particularly the general course control problem has been extended to 3-D with the new definition of vertical-slip angle. The overall guidance system employing the revised relative system model, course control and speed allocation has performed well during path-following under strong ocean current and/or wave disturbances and measurement noises in both 2-D and 3-D scenarios. In 2-D and 3-D 4 degrees-of-freedom models (DOF), the common sway-underactuated and fully actuated cases are considered, and in 3-D 5-DOF model, sway and heave underactuated and fully actuated cases are considered. Stability results of the LOS guidance laws include the semi-global exponential stability (SGES) of the switching LOS guidance and enclosure-based LOS guidance for straight and curved paths, and SGES of the loolahead-based LOS guidance laws for curved paths. Feedback sliding mode and PID controllers are applied during PF providing a comparison between them, and simulations are carried out in MatLab.

To regain operation of a Minuteman Missile guidance computer, a ferromagnetic film was sprayed onto a previously inoperable memory disk after the original coating was removed using paint remover. The coating was then polished down to provide a smooth and uniform film, 1'he permanent data required for the clock and sector channels was determined from an operable Minuteman computer. 1-his information was then recorded on the memory disk using the write heads which were part of the complete memory unit. Digital electronics using integrated circuits provided theand generated the recording data _or the memory write heads. A "memory check" program verified the uniformity of the repaired memory by alternately writing "0' s" and "1' s" on each bit location and then reading and comparing the numbers to "0's" and "l's".Ball State UniversityMuncie, IN 47306

This thesis presents an integrated framework for online obstacle avoidance of rotary-wing unmanned aerial vehicles (UAVs), which can provide UAVs an obstacle field navigation capability in a partially or completely unknown obstacle-rich environment. The framework is composed of a LIDAR interface, a local obstacle grid generation, a receding horizon (RH) trajectory optimizer, a global shortest path search algorithm, and a climb rate limit detection logic. The key feature of the framework is the use of an optimization-based trajectory generation in which the obstacle avoidance problem is formulated as a nonlinear trajectory optimization problem with state and input constraints over the finite range of the sensor. This local trajectory optimization is combined with a global path search algorithm which provides a useful initial guess to the nonlinear optimization solver. Optimization is the natural process of finding the best trajectory that is dynamically feasible, safe within the vehicle's flight envelope, and collision-free at the same time. The optimal trajectory is continuously updated in real time by the numerical optimization solver, Nonlinear Trajectory Generation (NTG), which is a direct solver based on the spline approximation of trajectory for dynamically flat systems. In fact, the overall approach of this thesis to finding the optimal trajectory is similar to the model predictive control (MPC) or the receding horizon control (RHC), except that this thesis followed a two-layer design; thus, the optimal solution works as a guidance command to be followed by the controller of the vehicle. The framework is implemented in a real-time simulation environment, the Georgia Tech UAV Simulation Tool (GUST), and integrated in the onboard software of the rotary-wing UAV test-bed at Georgia Tech. Initially, the 2D vertical avoidance capability of real obstacles was tested in flight. Then the flight test evaluations were extended to the benchmark tests for 3D avoidance capability over the virtual obstacles, and finally it was demonstrated on real obstacles located at the McKenna MOUT site in Fort Benning, Georgia. Simulations and flight test evaluations demonstrate the feasibility of the developed framework for UAV applications involving low-altitude flight in an urban area.

Bibliography: p. 196-200. / M.I.T. Project DSR 76094. Contract no. NOW-66-0178-d.

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2010. / ENGLISH ABSTRACT: This thesis presents the design process of the movement control and guidance systems for an automated underwater vehicle (AUV) constructed by the Institute of Maritime Technology in Simon’s Town. The full non-linear mathematical model and simulation environment for the AUV were previously developed in [1]. The design process in this thesis covers an analysis of existing test data and the performance of the current systems in place on the AUV, derivation and analysis of the linear model for the AUV, design of upgraded control and guidance systems, analysis of the new designs including simulation results, practical implementation of the new designs and the results thereof. Over the course of this project a number of flaws were identified in the original control designs and other aspects of the AUV. Most notably, the capability of the AUV is limited owing to its construction, and the current control and guidance methods result in poor movement characteristics. The new control designs are executed through multiple SISO feedback loops, with the most complicated controllers consisting of proportional and integral control. A completely new guidance method was designed which grants theAUVthe ability to track both straight line and circular path segments with no steady state error. These designs were tested in simulation, with results showing good tracking performance, even in the presence of output disturbances. The new designs were implemented on the physical AUV, but testing was limited, with poor results being obtained. The poor test results were caused primarily by the construction of the AUV. / AFRIKAANSE OPSOMMING: Hierdie tesis stel die ontwerpsproses voor vir die bewegingsbeheer- en navigasiestelsels vir ’n outonome duikboot wat gebou is deur die Instituut vir Maritieme Tegnologie in Simonstad. Die volle nie-lineˆere wiskundige model en simulasieomgewing vir die duikboot is voorheen ontwikkel in [1]. Die ontwerpsproses in hierdie tesis behels ’n analise van bestaande toetsdata en van die werksverrigting van die stelsels wat tans op die duikboot ge¨ınstalleer is, die afleiding en analise van ’n lineˆere model vir die duikboot, die ontwerp van verbeterde beheer- en navigasiestelsels, die analise van die nuwe ontwerpe, wat simulasieresultate insluit, die praktiese implementering van die nuwe ontwerpe, en die resultate daarvan. Deur die loop van die projek is ’n aantal tekortkominge ge¨ıdentifiseer in die oorspronklike beheerstelselontwerpe en ander aspekte van die duikboot. Die mees beduidende tekortkominge is dat die vermo¨e van die duikboot beperk word deur die konstruksie daarvan, en dat die huidige beheer- en navigasietegnieke swak bewegingseienskappe lewer. Die nuwe beheerstelselontwerpe is uitgevoer deur ’n aantal enkelintree, enkeluittree terugvoerlusse, waar die mees komplekse beheerders bestaan uit proporsionele en integraalbeheer. ’n Heeltemal nuwe navigasiemetode is ontwerp, wat die duikboot in staat stel om beide reguit lyne en sirkulˆere padsegmente te volg sonder ’n stasionˆere volgfout. Hierdie ontwerpe is getoets in simulasie, waar die resultate goeie volging getoon het, selfs in die teenwoordigheid van uittreeversteurings. Die nuwe ontwerpe is ge¨ımplementeer op die fisiese duikboot, maar beperkte toetse is gedoen, en het swak resultate gelewer. Die swak toetsresultate was hoofsaaklik as gevolg van die konstruksie van die duikboot.

A escolha adequada de soluções para uma construção ou reforma para os clientes finais demanda informações que, apesar de aparentemente acessíveis através de sites de busca ou consulta a fabricantes, podem se mostrar complexas dependendo da escolha do sistema ou necessidade procurada dentro de uma loja. Com isso, verifica-se especificamente no setor de varejo de material de construção, vendas incorretas, incompletas, excesso ou desperdícios de materiais em obras, a situações que podem proporcionar acidentes graves. Diante deste fato, este trabalho tem como foco a proposta de um Sistema de Orientação Técnica (SOT) ao cliente do varejo de material de construção, que visa auxiliar os públicos relacionados em lojas de grande porte. Este trabalho busca auxiliar a informação na disseminação do conhecimento dentro do varejo de material de construção buscando minimizar perdas tangíveis (financeiras) e intangíveis (perdas de clientes por especificação inadequada). O estudo foi baseado na criação de uma plataforma que auxilia este público em relação às suas dúvidas para uma correta especificação. Como delimitação para o estudo de caso, adotou-se o tema \"impermeabilização\", utilizando-se um sistema de localização da patologia para a correta especificação da solução. Avaliou-se o SOT desenvolvido através de um estudo de caso em loja de material de construção, com clientes, vendedores e fabricante. Os resultados obtidos mostraram que o SOT pode ser desenvolvido com baixo investimento e prazo inferior a outras soluções, além de ter apresentado uma grande aceitação pelos clientes das lojas, assim como pelo fabricante e pelo varejo, parceiros neste estudo. / The proper choice of solutions for a construction or renovation by end customers demand information that, although apparently accessible through search engines or query the manufacturers, can show complex situations depending on the choice of system or need sought within a store. With that, specifically in the retail industry, building material sales incorrect, incomplete, or waste of materials in works, even situations that can provide major accidents. Given this fact, this work focuses on the proposal for a Technical Guidance System (TGS) retail customer of construction material, which aims to assist the public in large stores. This work seeks to assist in the dissemination of knowledge within the building material retailers seeking to minimize tangible (financial) losses and intangible assets (customer losses by inadequate specification). This study was based on the creation of a platform that helps this audience in relation to their questions for a correct specification. As delimitation for the case study, it was used the subject \"sealing\", using a system with the location of the pathology for the correct specification of the solution. The assessment of the TGS was developed through a case study in building material shop, with customers, building material dealers and manufacturer. The results obtained showed that the TGS can be developed with low investment and less time than other solutions, and has presented great acceptance by the customers of the stores, as well as by the manufacturer and retail, partners in this study.