Global ETD Search

21	Health Monitoring for Aircraft Systems using Decision Trees and Genetic Evolution Gerdes, Mike January 2019 (has links) (PDF) Reducing unscheduled maintenance is important for aircraft operators. There are significant costs if flights must be delayed or cancelled, for example, if spares are not available and have to be shipped across the world. This thesis describes three methods of aircraft health condition monitoring and prediction; one for system monitoring, one for forecasting and one combining the two other methods for a complete monitoring and prediction process. Together, the three methods allow organizations to forecast possible failures. The first two use decision trees for decision-making and genetic optimization to improve the performance of the decision trees and to reduce the need for human interaction. Decision trees have several advantages: the generated code is quickly and easily processed, it can be altered by human experts without much work, it is readable by humans, and it requires few resources for learning and evaluation. The readability and the ability to modify the results are especially important; special knowledge can be gained and errors produced by the automated code generation can be removed. A large number of data sets is needed for meaningful predictions. This thesis uses two data sources: first, data from existing aircraft sensors, and second, sound and vibration data from additionally installed sensors. It draws on methods from the field of big data and machine learning to analyse and prepare the data sets for the prediction process. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Instandhaltung Maschinelles Lernen Aeronautics Airplanes Decision trees Genetic algorithms Flugzeugsysteme Wartung Expert Systems Machine Learning Big Data Pattern recognition systems Condition Monitoring Remaining Useful Life Prediction Fuzzy Decision Tree Evaluation System Monitoring Aircraft Health Monitoring
22	Dynamic Cabin Air Contamination Calculation Theory Lakies, Marcel January 2019 (has links) (PDF) In this report an equation is derived to calculate the dynamic effect of primary and secondary aircraft cabin air contamination. The equation is applied in order to understand implications and hazards. Primary contamination is from an outside source in form of normal low level contamination or high level contamination in a failure case. Secondary contamination originates from deposited material released into the cabin by a trigger event. The dynamic effect is described as an initial value problem (IVP) of a system governed by a nonhomogeneous linear first order ordinary differential equation (ODE). More complicated excitations are treated as a sequence of IVPs. The ODE is solved from first principles. Spreadsheets are provided with sample calculations that can be adapted to user needs. The method is not limited to a particular principle of the environmental control system (ECS) or contamination substance. The report considers cabin air recirculation and several locations of contamination sources, filters, and deposit points (where contaminants can accumulate and from where they can be released). This is a level of detail so far not considered in the cabin air literature. Various primary and secondary cabin contamination scenarios are calculated with plausible input parameters taken from popular passenger aircraft. A large cabin volume, high air exchange rate, large filtered air recirculation rate, and high absorption rates at deposit points lead to low contamination concentration at given source strength. Especially high contamination concentrations would result if large deposits of contaminants are released in a short time. The accuracy of the results depends on the accuracy of the input parameters. Five different approaches to reduce the contaminant concentration in the aircraft cabin are discussed and evaluated. More effective solutions involve higher implementation efforts. The method and the spreadsheets allow predicting cabin air contamination concentrations independent of confidential industrial input parameters. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Passagierflugzeug Flugzeugkabine Aeronautics Airplanes Air--Pollution Aircraft cabins Luftverschmutzung Trikresylphosphat aircraft cabin cabin air ECS tricresyl phosphate TCP initial value problem IVP ordinary differential equation ODE air contamination concentration contaminant dynamics spreadsheet
23	Überprüfung einer einfachen Kopfrechenmethode zur Umrechnung der Fluggeschwindigkeit von CAS in TAS Lucht, Dennis January 2019 (has links) (PDF) Zweck - Von Piloten werden u.a. die sogenannten "Manual Flying Skills" gefordert. Dabei muss der Pilot in der Lage sein (ohne Autopiloten) nach grundlegenden Instrumenten zu fliegen. Dafür sind neben Geschick auch Faustformeln erforderlich. Die Faustformeln müssen dafür verlässlich sein. Der Inhalt dieser Arbeit beschäftigt sich exemplarisch mit einer Faustformel zur Umrechnung der kalibrierten Fluggeschwindigkeit (Calibrated Airspeed, CAS) in die wahre Fluggeschwindigkeit (True Airspeed, TAS). --- Methodik - In Excel und Matlab werden die Ergebnisse aus den Berechnungen der Faustformel mit dem Ergebnis einer exakten Berechnungsweise anhand flugmechanischer Formeln verglichen. Dabei wird die Flughöhe und Fluggeschwindigkeit variiert. Es werden die Abweichungen ermittelt und in Diagrammen zwei- und dreidimensional visualisiert. --- Ergebnisse - Die zu prüfende Faustformel liefert in dem für Sie vorgesehen Anwendungsbereich hinreichend genaue Ergebnisse mit Abweichungen unter 5 %. Dabei nehmen die Abweichung zu, umso weiter die Parameter (Höhe und Geschwindigkeit) von typischen Reiseflugbedingungen entfernt sind. --- Bedeutung in der Praxis - Piloten können bedenkenlos auf die in dieser Arbeit geprüfte Faustformel zurückgreifen und kommen so mit überschaubarem Kopfrechenaufwand auf relativ genaue Ergebnisse. --- Wert - Diese Arbeit zeigt, wie mit mäßigem Zeitaufwand in Excel eine Faustformel über einen gesamten Bereich geprüft werden kann. Das Vorgehen kann auf weitere Faustformeln übertragen werden, sodass sich ein Pilot sein "Kniebrett" mit verifizierten Faustformeln füllen kann. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Flugmechanik Fluggeschwindigkeit Aeronautics Airplanes Airplanes--Performance Airspeed airplanes Flughöhe Fluggeschwindigkeit Fluginstrumente Flugzeugführer Atmosphäre Näherungsrechnung Tabellenkalkulation Wahre Fluggeschwindigkeit Kalibrierte Fluggeschwindigkeit Kopfrechnung Kniebrett Altitudes Air speed Air-speed indicators Air pilots Atmosphere Mental arithmetic Electronic spreadsheets Calibrated Airspeed CAS True Airspeed TAS Manual Flying Skills MATLAB Excel
24	Basic Comparison of Three Aircraft Concepts: Classic Jet Propulsion, Turbo-Electric Propulsion and Turbo-Hydraulic Propulsion Rodrigo, Clinton January 2019 (has links) (PDF) Purpose - This thesis presents a comparison of aircraft design concepts to identify the superior propulsion system model among turbo-hydraulic, turbo-electric and classic jet propulsion with respect to Direct Operating Costs (DOC), environmental impact and fuel burn. --- Approach - A simple aircraft model was designed based on the Top-Level Aircraft Requirements of the Airbus A320 passenger aircraft, and novel engine concepts were integrated to establish new models. Numerous types of propulsion system configurations were created by varying the type of gas turbine engine and number of propulsors. --- Findings - After an elaborate comparison of the aforementioned concepts, the all turbo-hydraulic propulsion system is found to be superior to the all turbo-electric propulsion system. A new propulsion system concept was developed by combining the thrust of a turbofan engine and utilizing the power produced by the turbo-hydraulic propulsion system that is delivered via propellers. The new partial turbo-hydraulic propulsion concept in which 20% of the total cruise power is coming from the (hydraulic driven) propellers is even more efficient than an all turbo-hydraulic concept in terms of DOC, environmental impact and fuel burn. --- Research Limitations - The aircraft were modelled with a spreadsheet based on handbook methods and relevant statistics. The investigation was done only for one type of reference aircraft and one route. A detailed analysis with a greater number of reference aircraft and types of routes could lead to other results. --- Practical Implications - With the provided spreadsheet, the DOC and environmental impact can be approximated for any commercial reference aircraft combined with the aforementioned propulsion system concepts. --- Social Implications - Based on the results of this thesis, the public will be able to discuss the demerits of otherwise highly lauded electric propulsion concepts. --- Value - To evaluate the viability of the hydraulic propulsion systems for passenger aircraft using simple mass models and aircraft design concept. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Flugmechanik Betriebskosten Aeronautics Airplanes Airplanes--Performance Cost accounting Ölhydraulik Flugtriebwerk Elektroantrieb Kraftstoffverbrauch Flugzeug Entwurf Dimensionierung Aeroplanes Design Airplanes--Jet propulsion Airplanes--Turbofan engines Electric propulsion Hydraulics Airplanes--Fuel consumption Environmental protection Airbus A320 aircraft aircraft design flight mechanics engines hybrid propulsion hydraulics certification DOC Direct Operating Costs Airbus A320
25	Faktorgraph-basierte Sensordatenfusion zur Anwendung auf einem Quadrocopter Lange, Sven 12 December 2013 (has links) Die Sensordatenfusion ist eine allgegenwärtige Aufgabe im Bereich der mobilen Robotik und darüber hinaus. In der vorliegenden Arbeit wird das typischerweise verwendete Verfahren zur Sensordatenfusion in der Robotik in Frage gestellt und anhand von neuartigen Algorithmen, basierend auf einem Faktorgraphen, gelöst sowie mit einer korrespondierenden Extended-Kalman-Filter-Implementierung verglichen. Im Mittelpunkt steht dabei das technische sowie algorithmische Sensorkonzept für die Navigation eines Flugroboters im Innenbereich. Ausführliche Experimente zeigen die Qualitätssteigerung unter Verwendung der neuen Variante der Sensordatenfusion, aber auch Einschränkungen und Beispiele mit nahezu identischen Ergebnissen beider Varianten der Sensordatenfusion. Neben Experimenten anhand einer hardwarenahen Simulation wird die Funktionsweise auch anhand von realen Hardwaredaten evaluiert. info:eu-repo/classification/ddc/620 ddc:620
26	Evaluation of the Hybrid-Electric Aircraft Project Airbus E-Fan X Benegas Jayme, Diego January 2019 (has links) (PDF) Purpose - This master thesis evaluates the hybrid-electric aircraft project E-Fan X with respect to its economical and environmental performance in comparison to its reference aircraft, the BAe 146-100. The E-Fan X is replacing one of the four jet engines of the reference aircraft by an electric motor and a fan. A turboshaft engine in the cargo compartment drives a generator to power the electric motor. --- Methodology - The evaluation of this project is based on standard aircraft design equations. Economics are based on Direct Operating Costs (DOC), which are calculated with the method of the Association of European Airlines (AEA) from 1989, inflated to 2019 values. Environmental impact is assessed based on local air quality (NOx, Ozone and Particulate Matter), climate impact (CO2, NOx, Aircraft-Induced Cloudiness known as AIC) and noise pollution estimated with fundamental acoustic equations. --- Findings - The battery on board the E-Fan X it is not necessary. In order to improve the proposed design, the battery was eliminated. Nevertheless, due to additional parts required in the new configuration, the aircraft is 902 kg heavier. The turboshaft engine saves only 59 kg of fuel. The additional mass has to be compensated by a payload reduced by 9 passengers. The DOC per seat-mile are up by more than 10% and equivalent CO2 per seat-mile are more than 16% up in the new aircraft. --- Research limitations - Results are limited in accuracy by the underlying standard aircraft design calculations. The results are also limited in accuracy by the lack of knowledge of some data of the project. --- Practical implications - The report contributes arguments to the discussion about electric flight. --- Social implications - Results show that unconditional praise given to the environmental characteristics of this industry project are not justified. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Elektroantrieb Flugmechanik Aeronautics Airplanes Electric propulsion Airplanes--Performance Betriebskosten Kraftstoffverbrauch Luftverschmutzung Fluglärm Projektbewertung Technikbewertung Luftfahrttechnik Flugtriebwerk Passagier Flugzeug Entwurf Dimensionierung Cost accounting Airplanes--Fuel consumption Environmental protection Airplanes--Noise Evaluation Technology assessment Aerospace engineering Airplanes--Jet propulsion Airplanes--Turbofan engines Design aircraft aircraft design flight mechanics engines certification DOC Direct Operating Costs Airbus E-Fan X BAe 146

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