Global ETD Search

1	The aerodynamics of bird bodies Maybury, Will J. January 2000 (has links) No description available. 590
2	Airspeed estimation of aircraft using two different models and nonlinear observers Roser, Alexander, Thunberg, Anton January 2023 (has links) When operating an aircraft, inaccurate measurements can have devastating consequences. For example, when measuring airspeed using a pitot tube, icing effects and other faults can result in erroneous measurements. Therefore, this master thesis aims to create an alternative method which utilizes known flight mechanical equations and sensor fusion to create an estimate of the airspeed during flight. For validation and generation of flight data, a simulation model developed by SAAB AB, called ARES, is used. Two models are used to describe the aircraft behavior. One of which is called the dynamic model and utilizes forces acting upon the aircraft body in the equations of motion. The other model, called the kinematic model, instead describes the motion with accelerations of the aircraft body. The measurements used are the angle of attack (AoA), side-slip angle (SSA), GPS velocities, and angular rates from an inertial measurement unit (IMU). The dynamic model assumes that engine thrust and aerodynamic coefficients are already estimated to calculate resulting forces, meanwhile the kinematic model instead uses body fixed accelerations from the IMU. These models are combined with filters to create estimations of the airspeed. The filters used are the extended Kalman filter (EKF) and unscented Kalman filter (UKF). These are combined with the two models to create in total four methods to estimate the airspeed. The results show no major difference in the performance between the filters except for computational time, for which the EKF has the fastest. Further, the result show similar airspeed estimation performance between the models, but differences can be seen. The kinematic model manages to estimate the wind with higher details and to converge faster, compared to the dynamic model. Both models suffer from an observability problem. This problem entails that the aircraft needs to be maneuvered to excite the AoA and SSA in order for the estimation methods to evaluate the wind, which is crucial for accurate airspeed estimation. The robustness of the dynamic model regarding errors in engine thrust and aerodynamic coefficients are also researched, which shows that the model is quite robust against errors in these values. sensor fusion flight mechanics Kalman filter extended Kalman filter unscented Kalman filter pitot tube airspeed estimation simulation Control Engineering Reglerteknik
3	Vliv výpadku primárních letových informací na bezpečnost a spolehlivost letadlové techniky / THE EFFECT OF PRIMARY FLIGHT INFORMATION FAILURE ON SAFETY AND RELIABILITY OF AIRCRAFT Sklenář, Filip January 2021 (has links) It is necessary to have certain flight information available to control the airplane. This information is usually displayed on flight instruments, which are located on the dashboard of the aircraft. In case of loss of indication or misleading indication of certain devices, control of the aircraft can be very complicated or even impossible. The dissertation deals with the issue of loss of information indication from aerometric instruments (especially from the airspeed indicator). The work contains research on the course of degradation of total pressure measurements using a Pitot tube. Based on this research, it is possible to design a new system for detecting blockage of the Pitot tube, which will increase aviation safety. The phenomenon described was investigated in a wind tunnel and in real conditions. Furthermore, the work defines instructions for the compilation of an emergency procedure, which the pilot could use in the event of a fault condition with aerometric instruments. The real possibilities of use were demonstrated on a Cessna 172SP aircraft during the validation experiment. The validation experiment proved the possibilities of the safe usage of the emergency procedure during flight. The final part of the work is focused on the evaluation of possible changes in the creation of reliability and safety analyzes with regard to the application of new knowledge based on this work.
4	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
5	THE USE OF TELEMETRY DATA IN AN AIR DATA SYSTEM Morrison, Thomas M. 10 1900 (has links) ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Telemetry data are usually collected for analysis at some later time and can be monitored to follow the progress of a test. In the case of an Air Data System the signals from the sensors are sent to a computer that calculates the air data parameters for use on multiple LabView-generated displays, as well as to the Data Acquisition System. The readouts on the multiple displays need to be real-time so they are useful to the flight crew. Equations that control the different air data values are determined by what telemetry data are available and the preference of those doing the test planning. These systems need to display the information in a format useful to the flight crew and be reliable. Air Data System (ADS) Indicated Airspeed Indicated Mach Number Indicated Angle of Attack (AOA) Indicated Angle of Sideslip (AOS)
6	Improved State Estimation for Miniature Air Vehicles Eldredge, Andrew Mark 02 August 2006 (has links) (PDF) Research in Unmanned Air Vehicles (UAV's) continues to push the limitations of size and weight. As technical advances have made UAV's smaller and less expensive, they have become more flexible and extensive in their roles. To continue using smaller and less expensive components while retaining and even enhancing performance requires more sophisticated processing of sensor data in order for the UAV to accurately determine its state and thereby allow the use of feedback in controlling the aircraft automatically. This work presents a three-stage state-estimation scheme for the class of UAV's know as Miniature Air Vehicles (MAV's). The first stage estimates pitch and roll, the second stage estimates heading, and the third stage produces a position estimate and an estimate of wind speed and direction. All three stages make use of the extended Kalman filter, a framework for using a system dynamic model to predict future states and to update the predictions using weighted sensor measurements as they become available, where the weighting is based on the relative uncertainty of the dynamic model and the sensors. Using the three-stage state esti-mation scheme, significant improvements in the estimation of pitch, roll and heading have been achieved in simulation and flight testing. Performance of the navigation (position and wind) stage is comparable to an existing baseline algorithms for position and wind, and shows additional promise for use in dead reckoning when GPS updates become unavailable. Mechanical Engineering
7	Aerospace - Futuristický kokpit moderního letounu / Aerospace - Futuristic Aircraft Cockpit Design Bílek, Jan January 2010 (has links) This work describes the visualization design of the flight related quantities in a cockpit of a modern light sport aircraft. It focuses on the utilization of the state of the art trends in flight data displays and introduces the innovative implementation of the aircraft's energy state smart clues that reduce pilots' workload. The initial part of the work presents a research into the flight, engine and navigation data presentation on analog instruments, followed by their illustrative depiction in glass cockpits. Within the framework of this thesis, Microsoft Flight Simulator has been used as a source of the flight related data. Final advances in the display design were introduced through the implementation of the synthetic vision system and a visualization of the virtual tunnel in the sky.

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