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Modelling framework for flight dynamics of flexible aircraft

Modelling framework for flight dynamics of flexible aircraft

Each aerodynamic node has a 15 element state vector x associated with it, together with an input vector u consisting of angle of attack, angle of control surface and their rates of change (Andrews 2011, Lone 2013). For the AX-1 model, the surfaces generating lift are modelled using 58 aerodynamic nodes that result in 870 unsteady aerodynamic states. Steady aerodynamic coefficients for each section of the lifting surfaces are found from pre-programmed look-up tables (LUTs). Therefore, parameters such as viscous drag, zero lift drag, aerofoil profile drag and zero lift pitching moment coefficients and profile drag increase due to flaps are obtained through simple interpolation for a specified Mach number and Reynolds number. To take into account 3D effects, an indicial angle of attack (α ind ) is added to steady state
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Autonomous landing of a fixed-Wing unmanned aircraft with partialwing and stabiliser losses

Autonomous landing of a fixed-Wing unmanned aircraft with partialwing and stabiliser losses

Beeton presented his thesis on Fault-tolerant Flight Control of a UAV with Asymmetrical Damage to its Primary Lifting Surfaces [9]. In his thesis, the design, analysis, implementation and verification of a fault-tolerant flight control system were presented. A passive fixed-gain fault-tolerant approach was followed. A robust controller was implemented that was tolerant against the structural dam- age that causes asymmetrical flight dynamics. The goal was to keep flight stability after damage has occurred to the aircraft without any knowledge of the damage or when it occurred. The ro- bustness and performance of the autopilot were verified with simulations and practical flight tests. A successful practical flight test was demonstrated with 20% semi-span wing loss. Beeton found that the partial wing loss damage case only had a significant effect on the trim of the aircraft, and no significant effect on its dynamics. The logical next step is therefore to design a fixed-gain (non- adaptive) flight control system that is robust to partial stabiliser loss. The horizontal stabiliser loss and vertical stabiliser loss damage cases are chosen because it results in significant changes to both the trim and the dynamics of the aircraft. The flight control laws will therefore have to be able to find the new trim and also be robust to the changes in the aircraft dynamics. Furthermore, Beeton stated in his recommendations that the safety pilot struggled to land the aircraft when it suffered from partial wing loss. This was mainly due to higher landing speeds and pilot induced oscillations in the roll dynamics when approaching the touchdown point.
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On the development of computer code for aircraft flight dynamics analysis

On the development of computer code for aircraft flight dynamics analysis

To control the airplane‟s trajectory, it can be done by changing the external surfaces of the aircraft. Such external surfaces are elevators, stabilators, canards, elevons, tailerons, ailerons, rudders, and thrust vectoring nozzles. These external surfaces are often called as primary surfaces. Any operation applied to the primary surface will produce aircraft movement in pitch, roll, and yaw motion. Secondary flight control surfaces augment the primary surfaces by modifying the lift and drag characteristics of the wings and airplane. These secondary surfaces include wing flaps (usually on the trailing edge but sometimes used on the leading edge), wing slats, spoilers, and speed brakes. The recent terminology for primary flight controls is “flight control effectors,” as the effector may not be a conventional control surface. For example, NASA‟s F-15 ACTIVE research aircraft is said to have nine flight control effectors: left and right canards, left and right ailerons, rudder (the two rudders move together and are treated as one effector), left and right stabililators, and pitch or yaw T V
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Evolution of Aircraft Flight Control System and Fly-By-Light Flight Control System

Evolution of Aircraft Flight Control System and Fly-By-Light Flight Control System

As the speeds of the aircraft have increased, the need to increase data transmission rate from the pilot control panel to the control surface of the aircraft has also increased significantly. Higher data transmission rate necessitates higher bandwidth. Bandwidth is the amount of data that can be carried from one point to another in a given time period (usually a second). In aircraft higher bandwidth ensures higher data transfer rate, therefore pilots command passes rapidly from aircraft cockpit to control surfaces (like aileron, elevator, rudder) which ensures smooth aircraft manoeuvring. The higher the bandwidth, the larger the aircrafts safety margin in high gain tracking tasks.
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Design Of Vertical Take-Off And Landing (VTOL) Aircraft System

Design Of Vertical Take-Off And Landing (VTOL) Aircraft System

sometimes involves Aerodynamic surfaces in the powered air stream. In FFF control often depends on aerodynamic surfaces, including elevator, rudder, and ailerons, as with any typical airplane. In intermediate flight modes like Slow Forward Flight (SFF), all the methods of control are often simultaneously somewhat effective. The transition control often changes some important aspect of the aircraft configuration. Tilt rotors, or tilt propellers, often tilt motor pods to redirect the angle of thrust. Tilt wings, tilt the entire wing, motors and all. Tail sitters also do not change configuration but simply tilt the entire aircraft. It is not uncommon for the frame of reference to change for VTOL aircraft during transition. Roll often becomes Yaw and Yaw becomes Roll. The aircraft that do not change physical configuration there is often a marked change in the control system dynamics. Trim points will change, control throws need to change, and stability factors need to be modulated. The flight controller (FC) needs an input from the pilot telling it what flight mode, or percentage of transition is desired.
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Assessing GNSS integrity augmentation techniques in UAV sense and avoid architectures

Assessing GNSS integrity augmentation techniques in UAV sense and avoid architectures

The ABIA IFG module is designed to provide CIF and WIF alerts in real-time (i.e., in accordance with the specified TTC and TTW requirements in all relevant flight phases) [1-5]. The GNSS and Sensors Layer (GSL) passes the aircraft Position, Velocity, Time (PVT) and attitude (Euler angles) data (from the on board Inertial Navigation Systems, Air Data Computer, etc.), GNSS data (raw measurements and PVT) and the Flight Control System (FCS) actuators data to the Data Extraction Layer (DEL). At this stage, the required Navigation and Flight Dynamics (NFD) and GNSS Constellation Data (GCD) are extracted, together with the relevant information from an aircraft Three-Dimensional Model (3DM) and from a Terrain and Objects Database (TOD). The 3DM database is a detailed geometric model of the aircraft built in a Computer Aided Three-dimensional Interactive Application (CATIA). The TOD uses a Digital Terrain Elevation Database (DTED) and additional man-made objects data to obtain a detailed map of the surfaces neighbouring the aircraft. In the Integrity Processing Layer (IPL), the Doppler Analysis Module (DAM) calculates the Doppler shift by processing the NFD and GCD inputs. The Multipath Analysis Module (MAM) processes the 3DM, TOD, GNSS Constellation Module (GCM) and A/C Navigation/Dynamics Module (ADM) inputs to determine multipath contributions from the aircraft (wings/fuselage) and from the terrain/objects close to the aircraft. The Obscuration Analysis Module (OAM) receives inputs from the 3DM, GSCS and ADS, and computes the GNSS antenna obscuration matrixes corresponding to the various aircraft manoeuvres [6]. The Signal Analysis Module (SAM) calculates the C/N 0 of the direct GNSS signals received by the aircraft in the presence
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Model-based fault diagnosis for aerospace systems: a survey

Model-based fault diagnosis for aerospace systems: a survey

Inversion-based FDI reconstructs control inputs to diagnose faults [292, 293]. The left-inverse of the non-linear system [294] is computed to obtain a new dynamical model that reconstructs faults from origi- nal inputs, outputs, and their successive derivatives. Considering the problem from the input side is an interesting and relevant change of viewpoint, since most fault diagnosis methods generate residuals by comparing estimated outputs with their measured values. In this context, the fact that most aerospace vehicles are equipped with an IMU (Table 1) makes it possible to use the force equation as a static relation to reconstruct control inputs that have been achieved by actuators [135, 136]. Residuals can then be gener- ated by comparing these reconstructed inputs with the values that have been sent by the control algo- rithm to the system, without the need to integrate a dynamical model.
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Vol 10, No 1 (2014)

Vol 10, No 1 (2014)

A study was carried out to recommend efficient numerical integration and table look up techniques suitable for real time flight simulation comprising of system of stiff ordinary differential equations. Numerical integration and table lookup techniques available in literature were implemented in a real time flight simulator facility designed and developed in house. Aircraft pitch control system representing the slow and fast subsystems was considered for the study on numerical integration techniques. Table lookup techniques such as linear search and index computation methodology using Virtual Equi- Spacing concept have been studied for an example of the engine database of a high performance fighter aircraft. The Virtual Equi-Spacing is a new
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1.1. School of Aerospace and Mechanical Engineering

1.1. School of Aerospace and Mechanical Engineering

The Mechanical Engineering Major endeavors to educate students in becoming creative and competent engineers in the field of Mechanical Engineering and also in Aerospace Engineering. In regard to aerospace applications, an emphasis is placed on the understanding of basic theories for power plants such as gas turbines, rocket motors and ramjet engines. Students will study the basic theories of mechanical engineering as well as applied knowledge about the design, development and manufacturing of vehicles and machines. Courses in the major include thermal mechanics, fluid mechanics, mechanical materials, solid dynamics, internal combustion engines, gas turbines, production engineering, and automation, automatic control and system engineering. This major allows students to choose career paths along diverse application areas in the engineering field and encourages graduates to find rewarding opportunities in industries, governmental agencies and national research institutes.
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Complete services provided to your complete satisfaction

Complete services provided to your complete satisfaction

Jet Aviation retains DERs with an array of delegated authorizations. Obtaining this special authority is a lengthy process requiring adherence to strict educational, recurrent training and experience guidelines. As an STC ODA, Jet Aviation is authorized to issue Supplemental Type Certificates, Special Airworthiness Certificates for aircraft that are altered under an STC project and require flight tests, and to amend standard airworthiness

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IBM Global Business Services. IBM Institute for Business Value. Aerospace and Defense. Keep them flying. Find your winning position in the MRO game

IBM Global Business Services. IBM Institute for Business Value. Aerospace and Defense. Keep them flying. Find your winning position in the MRO game

• More electronic functionality: Electronic systems continue to replace mechanical systems. As electronics systems become more complex, companies will require increasingly specialized skills for after- market service and repair – which may invite OEMs further into the service mix. Underlying all of these dynamics is the fact that the aircraft maintenance business is capital-intensive and that the key to making the business equation work is to achieve economies of scale. To that end, many MRO companies are continuing to expand into locations such as Eastern Europe, China, Indonesia, and the Philippines.
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Robust Fault Diagnosis for Fixed Wing Aircraft Fault Tolerant Flight Control System

Robust Fault Diagnosis for Fixed Wing Aircraft Fault Tolerant Flight Control System

The aircraft stability is analysed for icing and normal condition [9]. The simulated aircraft attributes were compared for normal flight and icing flight condition and observed that icing changes the geometry and thus equilibrium point of the aircraft. The controllability analysis of tandem quad-copter was carried out [10]. FDI scheme is developed by comparison of required attitude to the measured attitude [11]. Sensor fusion technique is applied to estimate fault in altitude estimation [12]. The real-time parameters of aerodynamic model were estimated using artificial intelligence [13]. The method of system identification was explained briefly for a small unmanned aircraft [14]. The real-time parameter estimation of aircraft was carried out using recursive least square and batch estimation method [15] and minimized error in each model. System identification using subscale methods were explained for small flexible aircraft [16]. FDI methods classified as data-driven or model reference approach for diagnosing fault[21]. So far, FTFC has been implemented in control reallocation with FDI or control by nullifying errors using proper corrective measures. The input signal or output performance was estimated for designing FDI.
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Rotorcraft Trajectory Tracking by Supervised NLI Control

Rotorcraft Trajectory Tracking by Supervised NLI Control

Abstract— The purpose of this communication is to present a new nonlinear control structure for trajectory tracking taking explicitly into account actuators saturation. Here trajectory tracking by a four rotor aircraft is considered. After introducing the flight dynamics equations for the four rotor aircraft, a trajectory tracking control structure based on a two layer non linear inverse approach is adopted and a supervision layer is introduced to take into account the possible actuators saturation.

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* * * * * Virginia Aviation History Project. Virginia Tech Airport Civilian Pilot Training Program Linda Burdette

* * * * * Virginia Aviation History Project. Virginia Tech Airport Civilian Pilot Training Program Linda Burdette

The Civil Aeronautics Authority regulations required a CPTP-participating flight school to own one aircraft for every ten students enrolled in the program. (Note: VPI began with four airplanes and 50-80 students, a situation that continued for at least one year. Apparently, with aircraft production shifting to military aircraft vice general aviation aircraft, the CAA elected not to strictly enforce this regulation.) Furthermore, the CAA requirements specified for the training aircraft were very strict and excluded many types of aircraft available at that time. VPI adopted the Fleet training planes which were especially designed as a medium weight training plane and were extremely well adapted to student instruction. The two-place open cockpit bi-planes were equipped with Warner, 125 horse-power, radial engines. They were able to cruise at 98 miles per hour, land at 47 miles per hour, and had a cruising range of approximately 315 miles. In designing the Fleet, the designers attempted to incorporate the flying and performance characteristics of a wide variety of airplanes. Afterward, the students were able to adapt easily to most types of general aviation aircraft.
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Evaluating GNSS integrity augmentation techniques for UAS sense and avoid

Evaluating GNSS integrity augmentation techniques for UAS sense and avoid

 When the multipath ranging error exceeds 2 metres and the aircraft flies in proximity of the ground (below 500 ft AGL), the warning integrity flag shall be generated. In order to define the integrity thresholds associated with Doppler and fading effects, a dedicated analysis of the GNSS receiver tracking performance was performed. When the GNSS measurement errors exceed certain thresholds, the receiver loses lock to the satellites. Since both the code and carrier tracking loops are nonlinear, especially near the threshold regions, only Monte Carlo simulations of the GNSS receiver in different dynamics and SNR conditions can determine the receiver tracking performance [8, 9]. Numerous sources of measurement errors affect the Phase Lock Loop (PLL), Frequency Lock Loop (FLL) and Delay Lock Loop (DLL). PLL, FLL and DLL are adopted in Scalar Tracking Loops (STL) as well as Vector Tracking Loops (VTL) are considered as part of this research. Error models described in [10] allow determining the effective Carrier-to-Noise ( C/N ଴ ) ratio corresponding to the receiver tracking thresholds. The integrity flag criterion applicable to the ABIA system is:
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Security Measures and Procedures for Aircraft In-Flight Protection

Security Measures and Procedures for Aircraft In-Flight Protection

Mezi trestnými činy lze jmenovat nezákonné a úmyslné spáchání násilného činu vůči osobě na palubě letadla za letu, může-li to vést k ohrožení bezpečnosti letadla, zničení neb[r]

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Flight simulator transfer of training study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Aviation at Massey University

Flight simulator transfer of training study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Aviation at Massey University

Flight data was recorded to determine the participants' performance when flying the NOB holding pattern in the aircraft and the resulting flight times were used to determine the Percent [r]

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Flight simulator transfer of training study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Aviation at Massey University

Flight simulator transfer of training study : a thesis presented in partial fulfilment of the requirements for the degree of Master of Aviation at Massey University

Flight data was recorded to determine the participants' performance when flying the NOB holding pattern in the aircraft and the resulting flight times were used to determine the Percent [r]

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Models and the scaling of energy costs for locomotion

Models and the scaling of energy costs for locomotion

Flying insects, birds and bats use their wings to drive air downward, exerting on the air a downward force that balances body weight. In fast forward flight, the speeds of the beating wings relative to the body are low compared to the speed of the body relative to the air. In slow and hovering flight, the reverse is true. We can make rough estimates of mechanical energy costs by modelling fast fliers as fixed-wing aircraft (following Pennycuick, 1969, with modifications) and slow fliers as helicopters (Weis-Fogh, 1973). The cruising flight of birds, bats and large insects such as locusts is fast in this sense. Hummingbirds and many insects hover, and even in cruising flight the wings of small insects move much faster than their bodies; their flight is slow, in the sense used in this paragraph. Flow over the wings of aeroplanes and the rotors of helicopters is steady, in the sense that velocities remain constant. In contrast, flow over a flapping wing is unsteady. Aerodynamic forces acting in unsteady systems cannot be predicted accurately by equations for steady flow. Consequently, calculations based on steady aerodynamics, of the power required for flapping flight, are subject to error (Ellington, 1995; Rayner, 1995b). The greater the distance travelled by the wing in a single beat, expressed as a multiple of its chord length, the less serious are these errors likely to be. Thus they are likely to be less serious in fast flight, than in slow flight or hovering. In this paper, which requires only rough answers, I tolerate the errors for the sake of simplicity.
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The impact of altitude, latitude, and endurance duration on the design of a high altitude, solar powered unmanned aerial vehicle

The impact of altitude, latitude, and endurance duration on the design of a high altitude, solar powered unmanned aerial vehicle

Abstract— In this paper, a previously developed conceptual design tool has been used to study the impact of the latitude, altitude, and the flight duration on the weight estimation and the main characteristics of a high altitude, long endurance and solar powered unmanned aerial vehicle. The available solar energy during the daylight hours has been calculated at given locations and altitudes for specific periods to be used in the pre-conceptual design stage. The pre-conceptual design methodology is based on an analytical and continuous method, which consists of establishing the relationships between all the components with analytical functions using the component characteristics. This design approach can directly provide a unique and optimal design. This study is conducted for a solar aircraft designed for a surveillance mission over Iraq. It is concluded that increasing the operational altitude can lead to a heavier aircraft in spite of the high levels of the available solar energy that can be absorbed. Hence, at high altitude, the surface area required for solar power generation is less than that needed to obtain adequate lift. Increasing the maximum solar irradiance during the daylight hours can lead to further lowering of the aircraft weight. Moreover, an increase in the daylight hours can be beneficial if the charging and discharging losses of the fuel cells are considered.
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