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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Fuzzy Logic Guidance System Design For Guided Missiles

Vural, Ozgur Ahmet 01 January 2003 (has links) (PDF)
This thesis involves modeling, guidance, control, and flight simulations of a canard controlled guided missile. The autopilot is designed by a pole placement technique. Designed autopilot is used with the guidance systems considered in the thesis. Five different guidance methods are applied in the thesis, one of which is the famous proportional navigation guidance. The other four guidance methods are different fuzzy logic guidance systems designed considering different types of guidance inputs. Simulations are done against five different target types and the performances of the five guidance methods are compared and discussed.
22

Development of a dynamic model of a ducted fan VTOL UAV

Zhao, Hui Wen, zhwtkd@hotmail.com January 2010 (has links)
The technology of UAV (Unmanned Aerial Vehicle) has developed since its conception many years ago. UAVs have several features such as, computerised and autonomous control without the need for an on-board pilot. Therefore, there is no risk of loss of life and they are easier to maintain than manned aircraft. In addition, UAVs have an extended range/endurance capability, sometimes for several days. This makes UAVs attractive for missions that are typically
23

Development of an experimental aircraft/ship dynamic interface analysis motion facility for the investigation of helicopter manoeuvring /

Feldman, Amanda R. January 1900 (has links)
Thesis (M. App. Sc.)--Carleton University, 2004. / Includes bibliographical references (p. 139-144). Also available in electronic format on the Internet.
24

Active Noise Reduction Versus Passive Designs in Communication Headsets: Speech Intelligibility and Pilot Performance Effects in an Instrument Flight Simulation

Valimont, Robert Brian 08 May 2006 (has links)
Researchers have long known that general aviation (GA) aircraft exhibit some of the most intense and potentially damaging sound environments to a pilot's hearing. Yet, another potentially more ominous result of this noise-intense environment is the masking of the radio communications. Radio communications must remain intelligible, as they are imperative to the safe and efficient functioning of the airspace, especially the airspace surrounding our busiest airports, Class B and Class C. However, the high amplitude, low frequency noise dominating the GA cockpit causes an upward spreading of masking with such inference that it renders radio communications almost totally unintelligible, unless the pilot is wearing a communications headset. Even with a headset, some researchers have stated that the noise and masking effects overcome the headset performance and still threaten the pilot's hearing and overall safety while in the aircraft. In reaction to this situation, this experiment sought to investigate the effects which active noise reduction (ANR) headsets have on the permissible exposure levels (PELs), speech intelligibility, workload, and ultimately the pilot's performance inside the cockpit. Eight instrument-rated pilot participants flew through different flight tasks of varying levels and types of workload embedded in four 3.5 hour flight scenarios while wearing four different headsets. The 3.5 hours were considered long duration due the instrument conditions, severe weather conditions, difficult flight tasks, and the fatiguing effects of a high intensity noise environment. The noise intensity and spectrum in the simulator facility were specifically calibrated to mimic those of a Cessna 172. Speech intelligibility of radio communications was modified using the Speech Transmission Index (STI), while measures of flight performance and workload were collected to examine any relationships between workload, speech intelligibility, performance, and type of headset. It is believed that the low frequency attenuation advantages afforded by the ANR headset decreased the signal-to-noise ratio, thereby increasing speech intelligibility for the pilot. This increase may positively affect workload and flight performance. Estimates of subjective preference and comfort were also collected and analyzed for relevant relationships. The results of the experiment supported the above hypotheses. It was found that headsets which incorporate ANR technology do increase speech intelligibility which has a direct inverse influence on workload. For example, an increase in speech intelligibility is seen with a concomitant decrease in pilot workload across all types and levels of workload. Furthermore, flight task performance results show that the pilot's headset can facilitate safer flight performance. However, the factors that influence performance are more numerous and complex than those that affect speech intelligibility or workload. Factors such as the operational performance of the communications system in the headset, in addition to the ANR technology, were determined to be highly influential factors in pilot performance. This study has concluded that the pilot's headset has received much research and design attention as a noise attenuation device. However, it has been almost completely overlooked as a tool which could be used to facilitate the safety and performance of a general aviation flight. More research should focus on identifying and optimizing the headset components which contribute most to the results demonstrated in this experiment. The pilot's headset is a component of the aviation system which could economically improve the safety of the entire system. / Ph. D.
25

Augmenting low-fidelity flight simulation training devices via amplified head rotations

Le-Ngoc, Luan January 2013 (has links)
Due to economic and operational constraints, there is an increasing demand from aviation operators and training manufacturers to extract maximum training usage from the lower fidelity suite of flight simulators. It is possible to augment low-fidelity flight simulators to achieve equivalent performance compared to high-fidelity setups but at reduced cost and greater mobility. In particular for visual manoeuvres, the virtual reality technique of head-tracking amplification for virtual view control enables full field-of-regard access even with limited field-of-view displays. This research quantified the effects of this technique on piloting performance, workload and simulator sickness by applying it to a fixed-base, low-fidelity, low-cost flight simulator. In two separate simulator trials, participants had to land a simulated aircraft from a visual traffic circuit pattern whilst scanning for airborne traffic. Initially, a single augmented display was compared to the common triple display setup in front of the pilot. Starting from the base leg, pilots exhibited tighter turns closer to the desired ground track and were more actively conducting visual scans using the augmented display. This was followed up by a second experiment to quantify the scalability of augmentation towards larger displays and field of views. Task complexity was increased by starting the traffic pattern from the downwind leg. Triple displays in front of the pilot yielded the best compromise delivering flight performance and traffic detection scores just below the triple projectors but without an increase in track deviations and the pilots were also less prone to simulator sickness symptoms. This research demonstrated that head augmentation yields clear benefits of quick user adaptation, low-cost, ease of systems integration, together with the capability to negate the impact of display sizes yet without incurring significant penalties in workload and incurring simulator sickness. The impact of this research is that it facilitates future flight training solutions using this augmentation technique to meet budgetary and mobility requirements. This enables deployment of simulators in large numbers to deliver expanded mission rehearsal previously unattainable within this class of low-fidelity simulators, and with no restrictions for transfer to other training media.
26

Dynamic Wake Distortion Model for Helicopter Maneuvering Flight

Zhao, Jinggen 10 April 2005 (has links)
A new rotor dynamic wake distortion model, which can be used to account for the rotor transient wake distortion effect on inflow across the rotor disk during helicopter maneuvering and transitional flight in both hover and forward flight conditions, is developed. The dynamic growths of the induced inflow perturbation across the rotor disk during different transient maneuvers, such as a step pitch or roll rate, a step climb rate and a step change of advance ratio are investigated by using a dynamic vortex tube analysis. Based on the vortex tube results, a rotor dynamic wake distortion model, which is expressed in terms of a set of ordinary differential equations, with rotor longitudinal and lateral wake curvatures, wake skew and wake spacing as states, is developed. Also, both the Pitt-Peters dynamic inflow model and the Peters-He finite state inflow model for axial or forward flight are augmented to account for rotor dynamic wake distortion effect during helicopter maneuvering flight. To model the aerodynamic interaction among main rotor, tail rotor and empennage caused by rotor wake curvature effect during helicopter maneuvering flight, a reduced order model based on a vortex tube analysis is developed. Both the augmented Pitt-Peters dynamic inflow model and the augmented Peters-He finite state inflow model, combined with the developed dynamic wake distortion model, together with the interaction model are implemented in a generic helicopter simulation program of UH-60 Black Hawk helicopter and the simulated vehicle control responses in both time domain and frequency domain are compared with flight test data of a UH-60 Black Hawk helicopter in both hover and low speed forward flight conditions.
27

Development of real-time flight control system for low-cost vehicle

Du, Yongliang 01 1900 (has links)
In recent years, more and more light aircraft enter our daily life, from Agricultural applications, emergency rescue, flight experiment and training to Barriers to entry, light aircraft always have their own advantages. Thus, they have become more and more popular. However, in the process of GDP research about Flight Control System design for the Flying Crane, the author read a lot of literature about Flight Control System design, then noticed that the research in Flight Control System have apparently neglected to Low-cost vehicles. So it is necessary to do some study about Flight Control System for this kind of airplane. The study will more concern the control law design for ultra-light aircraft, the author hopes that with an ‘intelligence’ Flight Control System design, this kind of aircraft could sometimes perform flying tasks according to a prearranged flight path and without a pilot. As the Piper J-3 cub is very popular and the airframe data can be obtained more easily, it was selected as an objective aircraft for the control law design. Finally, a ¼ scale Piper J-3 cub model is selected and the aerodynamics coefficients are calculated by DATCOM and AVL. Based on the forces and moments acting on the aircraft, the trim equilibrium was calculated for getting proper dynamics coefficients for the selected flight conditions. With the aircraft aerodynamics coefficients, the aircraft dynamics characteristics and flying qualities are also analyzed. The model studied in this thesis cannot answer level one flying qualities in the longitudinal axis, which is required by MIL-F- 8785C. The stability augment system is designed to improve the flying qualities of the longitudinal axis. The work for autopilot design in this thesis includes five parts. First, the whole flight profile is designed to automatically control aircraft from takeoff to landing. Second, takeoff performance and guidance law is studied. Then, landing performance and trajectory is also investigated. After that, the control law design is decoupled into longitudinal axis and later-directional axis. Finally, simulation is executed to check the performance for the auto-controller.
28

Modeling, simulation, hardware development, and testing of a lab-scale airborne wind energy system

Klein-Miloslavich, Andreas 24 January 2020 (has links)
Airborne Wind Energy Systems (AWES) harness the power of high-altitude winds using tethered planes or kites. Continuous and reliable operation requires that AWES become autonomous devices, but the wind intermittency forces the system to repeatedly take-off to start, and land to shut-off. Therefore, a common approach to facilitate the operation is implementing Vertical take-off and landing (VTOL) functionality. This thesis models and simulates AWES flights working towards the implementation of flight controller hardware and autonomous operation of an AWES demonstrator platform. The Ardupilot open-source autopilot platform provides a convenient tool for modeling, simulation, and hardware implementation of small-scale airplanes. An AWES lab-scale demonstrator was developed to obtain operational insight, get preliminary flight data, and real-world experience in this technology. A quadplane was developed by combining a structurally reinforced glider with VTOL and autopilot components. Its performance is obtained from static and aerodynamic studies and converted into the Ardupilot parameter format to define it in the simulation. An AWES flight model was developed from the ground up to evaluate the performance of a simple flight controller in trajectory tracking. The Ardupilot Software-in-Loop (SIL) tool expands the simulation capabilities by running the flight controller code without requiring any hardware. This allowed controller tuning and flight plan evaluation with a more advanced fight model. AWES crosswind flight simulation was only possible due to the incorporation of an elastic tether and an ideal winch into the physics model. As a result, different trajectories and configurations were tested to find the optimal parameters that were uploaded to the flight controller board. The operational capabilities of the AWES demonstrator were expanded with a flight testing campaign. By targeting individual objectives, each test gradually increased its complexity and ensured that the flight envelope was safely expanded. The results were validated with the simulation before moving on to the next flight test. The testing campaign is still underway due to challenges and limitations presented by the legal and logistical aspects of operating the quadplane. However, preliminary flight tests in VTOL mode have been completed and were consistent with the simulated results in terms of autonomous waypoint navigation and attitude control. / Graduate
29

Load State of an Aircraft with an Elastic Wing / Load State of an Aircraft with an Elastic Wing

Schoř, Pavel January 2018 (has links)
V této práci je navržena metoda výpočtu zatížení letadla s netuhým křídlem, založená na spojení panelové metody prvního řádu dle Katz and Plotkin, Low-Speed Aerodynamics, 2001 s metodou stukturální analýzy dle Píštěk et al., Pevnost a životnost letadel I, 1988 a Lebofsky,Numerically Generated Tangent Stiffness Matrices for Geometrically Non-Linear Struc- tures, 2013. Panelová metoda poskytuje přasná data pro výpočet zatížení křídla od vzdušných sil za předpokladu že lze dané proudění aproximovat po- mocí potenciálního proudění, Narozdíl metod založených na interakci s CFD metodami lze navrženou metodu používat i na bežném počítači.
30

Agentní systém řízení letového provozu / Agent Approach to Air Traffic Control

Pomikálek, Jiří January 2020 (has links)
Tato práce je zaměřena na agentní návrh v prostředí řízení letového provozu. Hlavním cílem je vytvoření agentních systémů pro pilotní a řídící agenty, které odrážejí typické situace v prostředí řízení letového provozu.

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