Aircraft Maneuvers Research Articles

Analysis of Loss of Control Parameters for Aircraft Maneuvering in General Aviation

A rapid increase in the occurrence of loss of control in general aviation has raised concern in recent years. Loss of control (LOC) pertains to unique characteristics in which external and internal events act in conjunction. The Federal Aviation Administration (FAA) has approved an Integrated Safety Assessment Model (ISAM) for evaluating safety in the National Airspace System (NAS). ISAM consists of an event sequence diagram (ESD) with fault trees containing numerous parameters, which is recognized as casual risk model. In this paper, we outline an integrated risk assessment framework to model maneuvering through cross-examining external and internal events. The maneuvering is in the critical flight phase with a high number of LOC occurrences in general aviation, where highly trained and qualified pilots failed to maintain aircraft control irrespective of the preventive nature of the events. Various metrics have been presented for evaluating the significance of these parameters to identify the most important ones. The proposed sensitivity analysis considers the accident, fatality, and risk reduction frequencies that assist in the decision-making process and foresees future risks from a general aviation perspective.

Adaptive Strong Tracking Square-Root Cubature Kalman Filter for Maneuvering Aircraft Tracking

A novel strong tracking square-root cubature Kalman filter (SCKF) based on the adaptive current statistical (CS) model is proposed aiming at the maneuvering aircraft tracking problem. The Jerk input estimation is introduced on the basis of the modified input estimation algorithm in order to make the connection with the state process noise and the state error covariance matrix. Thus, the online-adaptive adjustment of the CS model is achieved. Additionally, the introduced position of the fading factor is re-deduced and a novel calculation method is designed in order to overcome the invalidity problem of the traditional fading factor. Two simulation scenarios are conducted to verify the effectiveness of the proposed algorithm. The simulation results show that the proposed algorithm possesses better adaptability and tracking precision than the two state-of-the-art single model filters. Moreover, the proposed algorithm decreases the runtime by 40% while maintaining the comparable performance compared with the interacting-multiple-model SCKF.

Математична модель керування безпілотним повітряним судном в одному каналі керування

Мета: Головна мета дослідження – створення математичної моделі модель керування безпілотним повітряним судном в одному каналі керування. Створена модель дозволить більш глибоко, якісно і швидше підібрати потрібні величини коефіцієнтів, необхідних для оптимальної і ефективної взаємодії людини і машини. Методи: Для створення математичної моделі керування безпілотним повітряним судном в одному каналі керування було застосовано класичну модель керування повітряним судном. Було застосовано порівняльний аналіз виконання повороту оператором безпілотного повітряного судна в ручному та напівавтоматичному режимі керування. Результати: Запропонована математична модель «Оператор – система дистанційного керування – безпілотне повітряне судно» під час зміни напрямку по курсу в горизонтальній площині. Модель враховує дії оператора під час керування безпілотним повітряним судном, маневреність повітряного судна обладнаним системою дистанційного керування та польотним контролером із можливістю вибору декількох режимів керування. Обговорення: Запропонована модель дає можливість проаналізувати особливості різних режимів керування безпілотним повітряним судном, які застосовуються при функціонуванні безпілотного повітряного судна. Вибір відповідних коефіцієнтів на різних режимах керування безпілотним повітряним судном дозволяє оптимально та ефективно взаємодіяти людині з машиною.

ПОЛУЭМПИРИЧЕСКИЕ НЕЙРОСЕТЕВыЕ МОДЕЛИ УПРАВЛЯЕМЫХ ДИНАМИЧЕСКИХ СИСТЕМ

В статье обсуждается проблема математического и компьютерного моделирования нелинейных управляемых динамических систем при недостаточности знаний об объекте моделирования и условиях его функционирования. Предлагаемый подход к решению этой проблемы основан на объединении возможностей теоретического и нейросетевого моделирования. Его работоспособность демонстрируется на примере моделирования движения и идентификации аэродинамических характеристик маневренного самолета. Предлагается алгоритм обучения полуэмпирической рекуррентной нейросетевой модели для решения задачи многошагового прогноза. В рамках данного алгоритма формируются и последовательно решаются оптимизационные подзадачи возрастающей сложности, при этом в качестве начальных приближений используются решения предыдущих подзадач. Также в работе рассматривается процедура получения репрезентативного набора обучающих данных посредством формирования полигармонических управляющих воздействий на объект моделирования. A simulation approach is discussed for maneuverable aircraft motion as nonlinear controlled dynamical system under multiple and diverse uncertainties including knowledge imperfection concerning simulated plant and its environment exposure. The suggested approach is based on a merging of theoretical knowledge for the plant with training tools of artificial neural network field. The efficiency of this approach is demonstrated using the example of motion modeling and the identification of the aerodynamic characteristics of a maneuverable aircraft. A semi-empirical recurrent neural network based model learning algorithm is proposed for multi-step ahead prediction problem. This algorithm sequentially states and solves numerical optimization subproblems of increasing complexity, using each solution as initial guess for subsequent subproblem. We also consider a procedure for representative training set acquisition that utilizes multisine control signals.

The Role of the Sympathoadrenomedullary System in the Formation of Pilot’s Adaptation to Flight Loads

The objective of this study was to evaluate the functions of the sympathoadrenomedullary system and the related psychophysiological reactions of pilots, depending on flying hours on a highly maneuverable aircraft. The study involved 78 volunteer pilots (41 high-maneuverability pilots and 37 bomber and transport aviation pilots). A set of methods was chosen with the possibility of their use according to the principle of comprehensive evaluation of the body functional state under flight loads taken into account. Our results indicate that highly maneuverable aircraft piloting induces a significant activation of the sympathoadrenomedullary system in pilots, compared to bombing and transport aircrafts. This is particularly common to young pilots with the total flying time of less than 1000 h. It has been recorded that changes in adaptation to the effect of flight factors on the body develop with age and flight experience.

The effect of electrohydrodynamic force on the lift coefficient of a NACA 0015 airfoil

Lift, the force component that is perpendicular to the line of flight, is generated when a small aircraft moves through the air. With the help of the sets of flaps and slats on its wing, the pilot controls his aircraft manoeuvring in the air. In this study, we preferred to cut the drawbacks of the flaps system by introducing the electrohydrodynamic actuator. Widely known as plasma actuator, it is able to improve the induced lift force as well as the efficiency of a small aircraft system. A dielectric-barrier-discharge actuator using a 6 kV AC power supply was developed and tested on a NACA 0015 airfoil using copper as the electrodes and kapton as its dielectric component. The experimental results showed that it was successful in presenting a positive effect of the plasma actuator on the lift coefficient of the airfoil at smaller angle of attack, where enhancements ranged between 0.7% and 1.8%. However, at a higher angle, the results were not as swayed as it was desired since the energy exerted by the plasma actuator on the lift performance of the airfoil was inadequate. Further tests are needed using higher rated voltage supply and other equipment to improve the capability of the actuator in refining the aerodynamic performance of the airfoil.

Solving the Air Conflict Resolution Problem Under Uncertainty Using an Iterative Biobjective Mixed Integer Programming Approach

In this paper, we tackle the aircraft conflict resolution problem under uncertainties. We consider errors due to the wind effect, the imprecision of aircraft speed prediction, and the delay in the execution of maneuvers. Using a geometrical approach, we derive an analytical expression for the minimum distance between aircraft, along with the corresponding probability of conflict. These expressions are incorporated into an existing deterministic model for conflict resolution. This model solves the problem as a maximum clique of minimum weight in a graph whose vertices represent possible maneuvers and where edges link conflict-free maneuvers of different aircraft. We then present a solution procedure focusing on two criteria, namely, fuel efficiency and the probability of reissuing maneuvers in the future: we iteratively generate Pareto front solutions to provide the controller with a set of possible solutions where she can choose the one corresponding the most to her preferences. Intensive Monte Carlo simulations validate the expressions derived for the minimum distance and the probability of conflict. Computational results highlight that up to 10 different solutions for instances involving up to 35 aircraft are generated within 3 minutes.

Experimental research into aerodynamic characteristics of the model of a maneuvered aircraft with an airflow passage through engines

We report results of experimental investigation of aerodynamic characteristics of an aircraft maneuvering model with and without a passage of airflow through the engines. During aero-tube experiment, research into the fighter aircraft models with round and rectangular shapes of nozzles was conducted. A basic method for studying aerodynamic characteristics is the weight experiment. When processing experimental data, we applied a method of corrections and calculated correction factors that depend on the shape of working part of the wind tunnel and relative dimensions of the model. The methodology for a comprehensive analysis of corrections and for determining magnitudes of the most important correction coefficients was developed, that is frontal drag and lifting force. Verification of the developed technique was carried out by comparing blowdown results of the fighter aircraft model of the MiG-29 type in the wind tunnel T-1 at Kharkiv National University of Air Forces named after Ivan Kozhedub with the results obtained from reliable semi-empirical dependences. Relative error of determining maximum aerodynamic quality of the aircraft was 3 % compared to the results of aerodynamic characteristics of the actual aircraft. The difference of the developed technique is the possibility of using interchangeable nozzles of engine imitators and the introduction of correction for the resistance of inner channels of the aircraft model’s nacelles. We demonstrated feasibility of the developed procedure for aero-tube experiment and adequacy of accounting for experimentally-determined corrections

Analysis of the Aircraft Motion at the Overcritical Angles of Attack: Errors of On-Board Measurements and Simulation of the Deviated Thrust Vector

The article deals with the problems of the flight test data analysis concerning the flights at higher then critical angles of attack in order to improve the mathematical model of an aircraft's motion. The paper presents a technique for validation and correction of the on-board measurements for this type of motion. Regarding the use of the vector control during such maneuvers, the article considers the mathematical model of the forces and torques generated by the thrust vectoring. Examples of the data processing of the modern maneuverable aircraft's flight tests are presented to confirm the efficiency of the proposed models and methods. The validation of the on-board measurements, above all, the aerometric measurements, is based on the equations of the aircraft spatial motion. It is assumed that the correct values of the motion parameters must satisfy the system of the nonlinear differential equations known from the flight dynamics. This approach has already proved its efficiency in the analysis of the flight data in the operational range of the angles of attack. The signals obtained through the simulation are used to correct the measurements in case of errors. The article presents examples of detection and correction of errors in the measurement channels for a true airspeed and angle of attack. This paper also proposes two versions of the model capable of calculation the projections of the forces and torques on the aircraft principal axes. The first version is derived from the evident geometrical considerations, the second one is based on Rodrigues' vector rotation formula known in the theoretical mechanics. A numerical comparison confirmed correctness of both obtained models. These models were also verified by processing of the flight tests data.

Enhancement of INS/GNSS integration capabilities for aviation-related Applications

Two methods for construction and use of integrated inertial and satellite systems are considered, taking into account the specific features of aviation-related applications, namely, alignment correction, and autocalibration. Alignment correction is performed during aircraft maneuvering on the airfield. Autocalibration of strapdown inertial navigation systems (SINS) is based on using the estimations of instrumental errors of inertial sensors, which had been obtained by the complex information processing (CIP) algorithm in a number of previous flights of the aircraft. The results of numerous flight tests of laser SINS designed by PAO MIEA for civil and military applications are provided as an evidence of high efficiency of the information integration methods proposed herein.

Effect of Impinging Wake Turbulence on the Dynamic Stall of a Pitching Airfoil

Dynamically moving airfoils are encountered in helicopter rotors, wind-turbine blades, and maneuvering aircraft. A clearer understanding of how freestream disturbances affect the aerodynamic forces on pitching airfoils leads to improved designs. In the present study, the authors’ recently validated spectrally accurate moving overlapping mesh methodology is used to perform a direct numerical simulation of a NACA 0012 airfoil pitching with oscillatory motion in the presence of a turbulent wake created by an upstream solid cylinder. The global computational domain is decomposed into a stationary background mesh, which contains the solid cylinder, and a mesh constructed around the airfoil that is constrained to pitch with predetermined reduced frequency . Present simulations are performed with chord-based Reynolds number . Aerodynamic forces and vortex-shedding properties are compared between the pitching airfoil simulations with and without upstream disturbances. Power spectral density functions of the aerodynamic forces and moments are investigated to further determine the effect of a turbulent wake on a pitching airfoil.

Robust adaptive tracking control of uncertain slowly switched linear systems

In this paper, robust adaptive tracking control schemes for uncertain switched linear systems subject to disturbances are investigated. The robust adaptive control problem requires the design of both adaptive and switching laws. A novel adaptive law is proposed based on an extended leakage approach, which does not require knowledge of the bounds of the uncertainty set. Two switching laws are developed based on extended dwell time (DT) strategies: (a) mode-dependent dwell time (MDDT); (b) mode–mode-dependent dwell time (MMDDT). MDDT exploits the information of the known reference model for every subsystem, i.e., the dwell time is realized in a subsystem sense. MMDDT is a variant of MDDT that can guarantee stability under faster switching than MDDT, provided that the next subsystem to be switched on is known. The proposed adaptive schemes can achieve global uniform ultimate boundedness for shorter switching intervals than state-of-the-art adaptive approaches based on DT. In addition to global uniform ultimate bounded stability, transient and steady-state performance bounds are derived for the tracking error. The numerical example of a highly maneuverable aircraft technology vehicle is adopted to demonstrate the effectiveness of the proposed adaptive methods.

The leading-edge vortex of swift wing-shaped delta wings.

Recent investigations on the aerodynamics of natural fliers have illuminated the significance of the leading-edge vortex (LEV) for lift generation in a variety of flight conditions. A well-documented example of an LEV is that generated by aircraft with highly swept, delta-shaped wings. While the wing aerodynamics of a manoeuvring aircraft, a bird gliding and a bird in flapping flight vary significantly, it is believed that this existing knowledge can serve to add understanding to the complex aerodynamics of natural fliers. In this investigation, a model non-slender delta-shaped wing with a sharp leading edge is tested at low Reynolds number, along with a delta wing of the same design, but with a modified trailing edge inspired by the wing of a common swift Apus apus. The effect of the tapering swift wing on LEV development and stability is compared with the flow structure over the unmodified delta wing model through particle image velocimetry. For the first time, a leading-edge vortex system consisting of a dual or triple LEV is recorded on a swift wing-shaped delta wing, where such a system is found across all tested conditions. It is shown that the spanwise location of LEV breakdown is governed by the local chord rather than Reynolds number or angle of attack. These findings suggest that the trailing-edge geometry of the swift wing alone does not prevent the common swift from generating an LEV system comparable with that of a delta-shaped wing.

Simulating actuator energy consumption for trajectory optimisation

This work aims to construct a high-speed simulation tool which is used to quantify the dynamic actuator power consumption of an aircraft in flight, for use within trajectory optimisation packages. The purpose is to evaluate the energy penalties of the flight control actuation system as an aircraft manoeuvre along any arbitrary trajectory. The advantage is that the approximations include major transient properties which previous steady state techniques could not capture. The output can be used to provide feedback to a trajectory optimisation process to help it compute the aircraft level optimality of any given flight path. The tool features a six degree of freedom dynamic model of an aircraft which is combined with low frequency functional electro-mechanical actuator models in order to estimate the major transient power demands. The actuator models interact with the aircraft using an aerodynamic load estimator which generates load forces on the actuators that vary as a function of flight condition and control surface demands. A total energy control system is applied for longitudinal control and a total heading control system is implemented to manage the lateral motion. The outer loop is closed using a simple waypoint following guidance system with turn anticipation and variable turn radius control. To test the model, a simple trajectory analysis is undertaken which quantifies a heading change executed with four different turn rates. The tool shows that the actuation system requires 12.8 times more electrical energy when performing a 90° turn with a radius of 400 m compared to 1000 m. A second test is performed to verify the model’s ability to track a longer trajectory under windy conditions.

Coordinated multi-aircraft 4D trajectories planning considering buffer safety distance and fuel consumption optimization via pure-strategy game

In this paper, we consider a coordinated multi-aircraft 4D (3D space plus time) trajectories planning problem which is illustrated by planning 4D trajectories for aircraft traversing an Air Traffic Control (ATC) sector. The planned 4D trajectories need to specify each aircraft’s position at any time, ensuring conflict-free and reducing fuel and delay costs, with possible aircraft maneuvers such as speed adjustment and flight level change. Different from most existing literature, the impact of buffer safety distance is also under consideration, and conflict-free is guaranteed at any given time (not only at discrete time instances). The problem is formulated as a pure-strategy game with aircraft as players and all possible 4D trajectories as strategies. An efficient maximum improvement distributed algorithm is developed to find equilibrium at which every aircraft cannot unilaterally improve further, without enumerating all possible 4D trajectories in advance. Proof of existence of the equilibrium and convergence of the algorithm are given. A case study based on real air traffic data shows that the algorithm is able to solve 4D trajectories for online application with estimated 16.7% reduction in monetary costs, and allocate abundant buffer safety distance at minimum separation point. Scalability of the algorithm is verified by computational experiments.

Extreme aircraft maneuver under sudden lateral CG movement: Modeling and control

Hitherto unaddressed issue of six degree-of-freedom transient dynamics during asymmetric ejection of stores with finite velocity, onboard a combat aircraft, is addressed and modeled from the first principle. Further, the effect of asymmetric center-of-gravity shift, post ejection of the store, on some complex high angle-of-attack maneuvers such as cobra and Herbst is also investigated. It is shown that the performance of the maneuvers drastically deteriorates when carried out with controller designed for the pre-ejection symmetric c.g. based dynamics. In order to improve the deteriorated performance, two new control schemes based on the standard sliding mode technique are proposed. The first sliding control is designed based on a simple ad-hoc model for the asymmetric dynamics, whereas the states are propagated using the exact model developed. It is shown that using this scheme the lost maneuver performance can be reasonably recovered. The second control scheme is formulated using an accurate asymmetric dynamics. This proposed control scheme almost completely recovers the original maneuver performance.

Numerical simulation of sonic boom focusing and its application to mission performance

This paper describes the effort undertaken to include numerical boom focusing on a lossy Burgers equation based sonic boom propagation tool called sBOOM. Traditional ray acoustics may break down during acceleration or other aircraft maneuvers that cause the ray tube area to approach zero. The paper describes a way to numerically predict focused sonic boom signatures using both Gill-Seebass similitude and the solution to the non-linear Tricomi equation that models the physics of boom focusing. The paper would then use this capability to determine focusing and non-focusing climb trajectories and their impact on mission performance.

Electromechanical actuator fan failure analysis and safety-critical design

The aim of this study is to use fault tree analysis to gain a better overall understanding of how to improve the reliability of a fan cooling system used to prevent electromechanical actuation systems (EMAs) from overheating. It is critical to manage the waste heat generated by EMAs on aircraft during all flight missions because EMA failure due to overheating could lead to an aircraft catastrophic failure. Heat generation by high-power-density power electronic devices and EMA motors has reached a heat flux density that thermal management of EMA by natural convection is not feasible, forced air cooling is needed. Since EMA motors and power electronic drives must operate at various altitudes and temperature throughout a flight mission, there is a need to develop a variable-speed fan that can operate efficiently and reliably over a wide range of pressure and temperature. To prevent EMAs from overheating and bring EMA failure probability to an acceptable level, a sturdy cooling fan which can operate under variable body forces due to aircraft maneuvering is required.

Can an aircraft be piloted via sonification with an acceptable attentional cost? A comparison of blind and sighted pilots

In the aeronautics field, some authors have suggested that an aircraft's attitude sonification could be used by pilots to cope with spatial disorientation situations. Such a system is currently used by blind pilots to control the attitude of their aircraft. However, given the suspected higher auditory attentional capacities of blind people, the possibility for sighted individuals to use this system remains an open question. For example, its introduction may overload the auditory channel, which may in turn alter the responsiveness of pilots to infrequent but critical auditory warnings. In this study, two groups of pilots (blind versus sighted) performed a simulated flight experiment consisting of successive aircraft maneuvers, on the sole basis of an aircraft sonification. Maneuver difficulty was varied while we assessed flight performance along with subjective and electroencephalographic (EEG) measures of workload. The results showed that both groups of participants reached target-attitudes with a good accuracy. However, more complex maneuvers increased subjective workload and impaired brain responsiveness toward unexpected auditory stimuli as demonstrated by lower N1 and P3 amplitudes. Despite that the EEG signal showed a clear reorganization of the brain in the blind participants (higher alpha power), the brain responsiveness to unexpected auditory stimuli was not significantly different between the two groups. The results suggest that an auditory display might provide useful additional information to spatially disoriented pilots with normal vision. However, its use should be restricted to critical situations and simple recovery or guidance maneuvers.

Numerical Analysis of Aerodynamic Characteristics of F-16

Maneuvering of the fighter aerodynamic have certain requirements, this paper for needs of F-16 aircraft maneuvering, according to some existing fighter of the gas dynamic layout and parameters and establish more accurate fighter aerodynamic configuration, internal structure parameters and control input quantity. This paper also introduces the standard atmosphere model and the engine model, and analyzes the control characteristics of the aircraft by verifying the zero input response and channel coupling characteristics, and analyzes the performance of the model. This method can be applied to the performance analysis of other models.