Flight Dynamics Research Papers - Academia.edu (original) (raw)

2025, IJETRM Journal

Increasingly, global concerns about the environment, regulations and calls for sustainability are pushing corporate aviation to make major changes. While most talk about sustainability in aviation stress technology and fuels, this article points out that corporate pilots can also be real sustainability champions. Working at the meeting point of flying and running aeroplanes, corporate pilots can help develop and implement environmentally friendly practices. This research states that corporate pilots can play a part in making sustainability decisions, not just with their flying but also by managing activities such as fuel, routing, aircraft performance and how materials are sourced. Additionally, when they participate in policy-making, engage stakeholders and collaborate with multiple groups, it becomes more likely for sustainability cultures to appear in corporate flight departments. Promoting environmental care during pilot training and standard flying practices is analyzed as a support for green flying by the airline. Using a mix of surveys, case evaluations and reviews of today's environmental groups for aviation, the paper reveals that pilots are helping to achieve environmental results. Critical factors examined are organizational indecision, a lack of knowledge about sustainable practices and inconsistencies between running the organization and protecting the environment. The article presents an approach that shows how corporate pilots can greatly assist sustainability by moving beyond technical duties to act as key leaders in making aeroplanes environmentally friendly.

2025, INCAS BULLETIN

In this paper, the investigation was performed to determine the effect of leading-edge angle and leading-edge sweep on the aerodynamic coefficients of the projectile geometry and analyze the effect of roll moment on the fins at various operating conditions. A group of four models were considered, standard TTCP with the blunt leading edge and with 45° leading-edge along with modified TTCP with the blunt leading edge along with 30° sweep and with 45° leading-edge along with 30° sweep. The flow field solutions were obtained and considered as a function of roll moment coefficients, which are then compared to other numerical models and experimental results. The standard wrap-around TTCP models were subjected to varying velocities ranging from Mach 1.5 to 2.5. WAFs are considered a choice for spinning tube-launched projectiles because of their high packing factor and instant deployment. The computational grids have been built to accurately reflect the fin edge shape of the experimental mo...

2025, … of the 32nd …

The present paper summarizes the results obtained during the validation phase of the aerodynamic computational tools performed in the framework of the European research project HeliNOVI and relative to the interactional phenomena arising... more

2025

This paper analyses the lateral stability of tailless CAMAR-3 Unmanned Aerial Vehicle (UAV) when its tail fin (i.e. V-tail) is reconfigured to the wingtips. A tailless UAV may have longer endurance time, compared to the present configuration of V-tail. Nevertheless, a tailless UAV may experience reduction in lateral stability due to loss of yaw control surfaces. In the preliminary design of tailless-winglets UAV, semi-empirical method is applied to estimate the aerodynamic lateral stability derivatives, in order to investigate the stability of both configurations of UAV. A dynamic test rig based on pure yawing motion is built, to measure the lateral stability derivatives of and The time response data of pure yawing oscillation give the natural frequency and damping ratio that describe the aerodynamic derivatives as a result from wind-on and wind-off tunnel tests. The result indicates that UAV with either configurations are laterally stable. However, the tailless-winglets CAMAR has...

2025

A time-series flight trajectory technique was developed for use in a civil aircraft during descent. The three-degree-of-freedom (3-DoF) equations of motion were solved via time-series prediction of aerodynamic forces. In the present evaluation, the microburst effect during the descent was considered. The single-objective optimization problem, in which the cost function indicating the trajectory efficiency was minimized, was solved by means of a Kriging model based genetic algorithm (GA) which produces an efficient global optimization process. The optimal trajectory results were compared with those without the microburst condition during the descent. The minimization solution converged well in each case for both conditions plus the differences in flight profiles based on the trajectory history were smaller than those of the solutions before optimization. An analysis of variance and parallel coordinate plot were applied to acquire the quantitative information for the initial condition...

2025

The quantification and prediction of the health status of aircraft are challenging aspects of Prognostics and Health Management (PHM). The Dutch PHM Consortium (DPC 1 ) develops concepts for prognostics and health management of aircraft. Within this framework there is a need to know the operation of the hydraulic system in flight. Usage data can be derived from data measured with dedicated sensors, but to keep aircraft weight, sensor failures and costs as low as possible there is a requirement to minimise the number of such sensors. Therefore a technique is developed to derive information about the operation of the hydraulic system from parameters measured during the flight for general purposes, the recorded flight data. Condition Parameters and Remaining Life Time of components can be derived with the technique. The force produced by the hydraulics and the displacements of the piston, being representative parameters for wear, can be calculated from flight data and an aerodynamic mo...

2025, Frontiers in aerospace engineering

We propose a closed-form system of nonlinear equations for the pitch plane or longitudinal motions of a fixed-wing aircraft and use it to demonstrate a possible path to the unification of theoretical flight dynamics and practical analysis of aircraft manoeuvres. The derivation of an explicit model free of data tables and interpolated functions is enabled by our use of empirical formulae for lift and drag which agree with experiments. We validate the model by recovering the wellknown short period and phugoid modes, and the regions of normal and reversed command. We then use the model to present detailed simulations of two acrobatic manoeuvres, an Immelmann turn and a vertical dive. Providing new quantitative insights into the dynamics of aviation, our model-based manoeuvre analysis has the potential to impact both the academic flight dynamics curriculum and the ground training program for pilots of manned and unmanned aircraft. Possible consequences of future model-centric pilot training may include improved safety standards in general and commercial aviation as well as expedited theoretical course completion in air transport.

2025

A Fault Detection and Identification (FDI) scheme for aircraft systems based on the modelling of relationships among flight variables is introduced. The modelling is performed by means of Time-dependent Functionally Pooled Nonlinear AutoRegressive with eXogenous (TFP-NARX) excitation representations. These are generalized NARX representations with (a) their parameters being functions of time-dependent flight variables and (b) the capability of describing a system under various operating conditions due to their pooled form. During the system's operation in healthy mode, these relationships are valid. Hence a scheme using statistical hypothesis testing is designed to detect changes in the relationships due to potential fault occurrence. The FDI scheme's performance and robustness are assessed with flights conducted under various flight conditions.

2025, Journal of KONES

The paper presents CAE MBS analysis of aircraft front landing gear behaviour in unusual situations that can be caused by unpredictable obstacles. Numerical tools were applied, because real investigations can be relatively expensive and dangerous. One of unusual maintenance condition assumed increasing of the aircraft vertical velocity, caused by a loss of uplift forces (result of decreasing the horizontal velocity to shorten the airfield length needed to dissipate aircraft energy). The other analyzed maintenance condition assumed the aircraft landing with horizontal velocity, increased of a large percentage in comparison with its maximum value allowed by the aircraft manufacturer. Simulation also provided the gear dynamics analysis while crossing over obstacles placed on slightly damaged or makeshift airfield. During CAE tests, Lagrange spring/dumper elements used to simulate the behavior of deformable tyre and shock absorber oil-gas mixture. Simulations proved that increasing the vertical velocity of 25% and the horizontal one of 15% is safe for the aircraft and it can operate on damaged airfields. Investigations proved that aircraft maintenance conditions might be safely expanded, in comparison with its manufacturer suggestions. It enables the manufacturer to look for new and aircraft-safe applications that require special landing capabilities: Special Team Transport or Medical Evacuation.

2025, Journal of KONES

2025, Physical Review Letters

The influence of flexibility on the flight of autorotating winged seedpods is examined through an experimental investigation of tumbling rectangular paper strips freely falling in air. Our results suggest the existence of a critical length above which the wing bends. We develop a theoretical model that demonstrates that this buckling is prompted by inertial forces associated with the tumbling motion, and yields a buckling criterion consistent with that observed. We further develop a reduced model for the flight dynamics of flexible tumbling wings that illustrates the effect of aeroelastic coupling on flight characteristics and rationalizes experimentally observed variations in the wing's falling speed and range.

2025

The dynamics of aircraft manoeuvring on the ground is nonlinear due to nonlinearities in tyres, in other landing gear components, and potentially in the aerodynamics of the airframe. Existing linear approaches are effective in respect of local behaviour around specific operating conditions, but in order to evolve a global understanding of the dynamics of an aircraft on the ground other techniques are needed. We demonstrate here that bifurcation analysis and continuation methods can be used for the purpose of building up a global stability diagram in a computationally efficient manner. Specifically, we perform a continuation study of a nonlinear tricycle model implemented in the SimMechanics environment and then coupled to the continuation software AUTO. Our study yields unexpected phenomena, namely a complicated structure of branches with hysteresis loops and instabilities leading to oscillations and even chaotic dynamics.

2025, Journal of the Royal Aeronautical Society

In this paper, the accuracy and practical capabilities of three different reduced-order models (ROMs) are explored: an enhanced implicit condensation and expansion (EnICE) model, a finite element beam model, and a finite volume beam model are compared for their capability to accurately predict the nonlinear structural response of geometrically nonlinear built-up wing structures. This work briefly outlines the different order reduction methods, highlighting the associated assumptions and computational effort. The ROMs are then used to calculate the wing deflection for different representative load cases and these results are compared with the global finite element model (GFEM) predictions when possible. Overall, the ROMs are found to be able to capture the nonlinear GFEM behaviour accurately, but differences are noticed at very large displacements and rotations due to local geometrical effects.

2025, AIAA Atmospheric Flight Mechanics Conference and Exhibit

This paper focuses on the characterization of the response of a very flexible aircraft in flight. The 6-DOF equations of motion of a reference point on the aircraft are coupled with the aeroelastic equations that govern the geometrically nonlinear structural response of the vehicle. A low-order strain-based nonlinear structural analysis coupled with unsteady finite-state potential flow aerodynamics form the basis for the aeroelastic model. The nonlinear beam structural model assumes constant strain over an element in extension, twist, and in/out of plane bending. The geometrically nonlinear structural formulation, the finite state aerodynamic model, and the nonlinear rigid body equations together provide a low-order complete nonlinear aircraft analysis tool. The equations of motion are integrated using an implicit modified generalized-alpha method. The method incorporates both first and second order nonlinear equations without the necessity of transforming the equations to first order and incorporates a Newton-Raphson sub-iteration scheme at each time step. Using the developed tool, analyses and simulations can be conducted which encompass nonlinear rigid body, nonlinear rigid body coupled with linearized structural solutions, and full nonlinear rigid body and structural solutions. Simulations are presented which highlight the importance of nonlinear structural modeling as compared to rigid body and linearized structural analyses in a representative High Altitude Long Endurance (HALE) vehicle. Results show significant differences in the three reference point axes (pitch, roll, and yaw) not previously captured by linearized or rigid body approaches. The simulations using both full and empty fuel states include level gliding descent, low-pass filtered square aileron input rolling/gliding descent, and low-pass square elevator input gliding descent. Results are compared for rigid body, linearized structural, and nonlinear structural response. Recent advances in airborne sensors and communication packages have brought the need for high-altitude long-endurance (HALE) aircraft. These platforms can be categorized under three broad missions, supporting either the military or civilian communities. The missions include airborne Intelligence, Surveillance, and Reconnaissance (ISR), for the military, 1 network communication nodes for the military and civilian usage, 2 and general atmospheric research. 2 Due to the mission requirements, the desired vehicles are characterized by high-aspect-ratio wings, slender fuselages, and slender control surfaces, resulting in highly flexible vehicles. Examples of mission optimization studies for this class of vehicle can be found in Ref. 1, where the authors show HALE aircraft are required to have a fuel fraction greater than 66%. This results in a very small structural weight fraction. The combination of high aerodynamic efficiency and low structural weight fraction yields inherently flexible wings. The HALE vehicle will then be susceptible to large dynamic wing deformations at low frequencies, presenting a direct impact into the flight dynamic characteristics of the vehicle. Aircraft elastic flight dynamics have been studied and analyzed for more than three quarters of a century. However research and applications of flexible aircraft dynamics have been based primarily on linear models or, at best, nonlinear rigid body vehicle dynamics coupled with linear structural dynamics. For the majority of conventional aircraft, linear analysis has been very successful in providing sound aircraft designs. But when analyzing aircraft with high-aspect-ratio wings and large fuel fractions, linear aeroelastic analysis is shown to be ineffective in capturing the relevant aircraft dynamics.

2025, Journal of Aircraft

This paper reviews the applicability of some conventional structural design practices to the analysis and design of very flexible aircraft. The effect of large structural deformations and the coupling between aeroelasticity and flight dynamics is investigated in different aspects of the aircraft structural design process, including aeroelastic stability, loads, and flight dynamics and control. This is illustrated with a numerical example of the static and dynamic responses of a representative high-altitude long-endurance vehicle. Suggestions are presented for the development of appropriate frameworks to design and analyze very flexible aircraft.

2025, Journal of Robotic Systems

This paper presents a mathematical model for a model‐scale unmanned helicopter robot, with emphasis on the dynamics of the flybar. The interaction between the flybar and the main rotor blade is explained in detail; it is shown how the flapping of the flybar increases the stability of the helicopter robot as well as assists in its actuation. The model helicopter has a fast time‐domain response due to its small size, and is inherently unstable. Therefore, most commercially available model helicopters use the flybar to augment stability and make it easier for a pilot to fly. Working from first principles and basic aerodynamics, the equations of motion for full six degree‐of‐freedom with flybar‐degree of freedom are derived. System identification experiments and results are presented to verify the mathematical model structure and to identify model parameters such as inertias and aerodynamic constants. © 2004 Wiley Periodicals, Inc.

2025, Aircraft Engineering and Aerospace Technology

PurposeTo describe how airline operational efficiency may be improved by adopting a socio‐technical systems approach which emphasises and integrates the role of human factors within a wider context.Design/methodology/approachAfter describing what is meant by a socio‐technical system, the paper uses four short case studies to illustrate the benefits and dis‐benefits of using (or failing to use) a socio‐technical systems approach.FindingsReaders are encouraged to acknowledge the role of the human being in a wider system context. It is also suggested that improving individual aspects of airline operations in isolation may not actually improve overall efficiency.Research/limitations/implicationsThe case studies discussed are meant to be illustrative of the socio‐technical systems approach rather than an authoritative review of the area.Practical implicationsThe practical implications of adopting a socio‐technical systems view of improvements aimed at improving efficiency are emphasised ...

2025, Journal of aerospace information systems

Identifying the drag parameters of UAVs is crucial for guaranteeing their aerodynamic efficiency. However, in contrast to commercial aircraft, obtaining accurate UAV drag parameters is challenging since the existing approaches rely on analytical models or require accurate modeling of the engine thrust, which highly depends on time-varying wind conditions. To address this challenge, this paper first proposes a novel in-flight estimation algorithm for the air data (airspeed, angle of attack, and sideslip angle) and drag parameters of UAVs. With this approach, there is no need to compute all of the contributing components for drag, to model the thrust of the UAVs or to perform complicated wind tunnel testing/computational fluid dynamics (CFD) analysis to obtain the drag parameter. Instead, the proposed algorithm requires only standard sensors such as inertial measurement units (IMUs) and air data systems during gliding flight. Then, an efficient glide phase detection algorithm for initiating the filter is proposed. Simulation and experimental flight testing of a UAV demonstrate that the proposed algorithm yields accurate zero lift drag coefficient, attitude, and air data estimation results according to thorough validation with newly derived metrics for performance evaluation. * Senior researcher, Unmanned aircraft system research division. † Principal researcher, Unmanned aircraft system research division. ‡ Principal researcher, Unmanned aircraft system research division. § Professor, Division of Engineering, Business, and Computing, Reading, PA.

2025, Journal of Astronomy and Space Sciences

This paper describes the Flight Dynamics Automation (FDA) system for COMS Flight Dynamics System (FDS) and its test result in terms of the performance of the automation jobs. FDA controls the flight dynamics functions such as orbit determination, orbit prediction, event prediction, and fuel accounting. The designed FDA is independent from the specific characteristics which are defined by spacecraft manufacturer or specific satellite missions. Therefore, FDA could easily links its autonomous job control functions to any satellite mission control system with some interface modification. By adding autonomous system along with flight dynamics system, it decreases the operator's tedious and repeated jobs but increase the usability and reliability of the system. Therefore, FDA is used to improve the completeness of whole mission control system's quality. The FDA is applied to the real flight dynamics system of a geostationary satellite, COMS and the experimental test is performed. The experimental result shows the stability and reliability of the mission control operations through the automatic job control.

2025, INCAS Buletin

This research presents a comprehensive analysis of the dynamic stability of aircraft using modules of the software named SCSim (Stability and Control Simulation Tool), which is dedicated to the analysis of aircraft stability and control. The stability of an aircraft can be examined in two directions: longitudinal and lateral. The ability to determine an aircraft's limits and handling qualities depends on its stability. This study report demonstrates a complete dynamic stability analysis using SCSim with aerodynamic input data from the commercial software Advanced Aircraft Analysis (AAA). SCSim is implemented within a common framework in MATLAB, adapted from a MATHCAD script, providing an easier way to enter user-defined input data, and introducing a set of new features. The study is divided into three main parts, each based on an analysis of stability. First, static stability is examined to understand how the system behaves when it is in equilibrium. Then, dynamic stability is assessed to understand how the system reacts to perturbations and disturbances. Finally, handling qualities systematically assess the dynamic modes of the aircraft's behavior and establish the levels of handling qualities. In this paper, a generic model of a propeller-driven aircraft is used for the study due to the availability of flight parameters, geometric, and aerodynamic data. The obtained results demonstrate the capabilities of the Stability and Control Simulation Tool (SCSim) in designing and analysing an aircraft's stability under various flight conditions and configurations, with validation using AAA.

2024, Nonlinear Dynamics

It is well known that a linear-based controller is only valid near the point from which the linearised system is obtained. The question remains as to how far one can move away from that point before the linear and nonlinear responses differ significantly, resulting in the controller failing to achieve the desired performance. In this paper, we propose a method to quantify these differences. By appending a harmonic oscillator to the equations of motion, the frequency responses at different operating points of a nonlinear system can be generated using numerical continuation. In the presence of strong nonlinearities, subtle differences exist between the linear and nonlinear frequency responses, and these variations are also reflected in the step responses. A systematic way of comparing the discrepancies between the linear and the nonlinear frequency responses is presented, which can determine whether the controller performs as predicted by linear-based design. We demonstrate the method on a simple fixed-gain Duffing system and a gain-scheduled reduced-order aircraft model with a manoeuvre-demand controller; the latter presents a case where strong nonlinearities exist in the form of multiple attractors. The analysis is then expanded to include actuator rate saturation, which creates a limit-cycle isola, coexisting multiple solutions (corresponding to the so-called flying qualities cliff), and chaotic motions. The proposed method can infer the influence of these additional attractors even when there is no systematic way to detect them. Finally, when severe rate saturation is present, reducing the controller gains can mitigate-but not eliminate-the risk of limitcycle oscillation.

2024, Journal of Aircraft

Non-dimensional coefficients for drag C L Non-dimensional coefficients for lift C l Non-dimensional coefficients for rolling moment C m Non-dimensional coefficients for pitching moment C n Non-dimensional coefficients for yawing moment C q Constraint Jacobian matrix C Y Non-dimensional coefficients for side force F c Externally applied tangential force compensating for spherical constraint effects F x , F y , F z Inertial axes forces L, D, Y Lift, drag, and side force l, m, n Rolling, pitching, and yawing moments M Mass and inertia tensor matrix m a Aircraft mass

2024, Journal of Robotic Systems

2024

The development of a toolset, SIMPLI-FLYD ("SIMPLIfied FLight dynamics for conceptual Design") is described. SIMPLI-FLYD is a collection of tools that perform flight dynamics and control modeling and analysis of rotorcraft conceptual designs including a capability to evaluate the designs in an X-Plane-based real-time simulation. The establishment of this framework is now facilitating the exploration of this new capability, in terms of modeling fidelity and data requirements, and the investigation of which stability and control and handling qualities requirements are appropriate for conceptual design. Illustrative design variation studies for single main rotor and tiltrotor vehicle configurations show sensitivity of the stability and control characteristics and an approach to highlight potential weight savings by identifying over-design. NOTATION  J Cost function for frequency response error Aircraft body axis roll rate Aircraft body axis pitch rate Aircraft body axis yaw rate

2024

The development of a toolset, SIMPLI-FLYD (“SIMPLIfied FLight dynamics for conceptual Design”) is described. SIMPLIFLYD is a collection of tools that perform flight dynamics and control modeling and analysis of rotorcraft conceptual designs including a capability to evaluate the designs in an X-Plane-based real-time simulation. The establishment of this framework is now facilitating the exploration of this new capability, in terms of modeling fidelity and data requirements, and the investigation of which stability and control and handling qualities requirements are appropriate for conceptual design. Illustrative design variation studies for single main rotor and tiltrotor vehicle configurations show sensitivity of the stability and control characteristics and an approach to highlight potential weight savings by identifying over-design.

2024

Nous abordons, dans cette thèse, la poursuite asymptotique de trajectoire basée sur la commande prédictive généralisée non linéaire à temps continu (NCGPC). L'application de cette technique de commande requiert la vérification d'assomptions précises. La NCGPC est caractérisée par deux paramètres : le degré relatif et l'horizon de prédiction, respectivement, intrinsèque et extrinsèque au système. Sa loi de commande résulte de la minimisation d'un critère quadratique basée sur l'erreur de prédiction (jusqu'à un ordre égal au degré relatif) entre la(es) sortie(s) choisie(s) et le(es) signal(aux) de référence correspondant(s). Elle linéarise le système non linéaire en boucle fermée dans un nouvel espace de coordonnées et lui garantit la stabilité (degré relatif inférieur ou égal à quatre) de facto. Au-delà de quatre, il y a instabilité. Pour résoudre ce problème, Chen et al. ont introduit un troisième paramètre, qui est l'ordre des dérivées successives de la commande par rapport au temps, choisi de sorte que sa différence avec le degré relatif soit inférieure à quatre. Nous proposons dans ce travail, deux approches qui vérifient les mêmes assomptions mentionnées ci-dessus et dont les points communs sont la modification du critère avec le maintien à zéro de l'ordre des dérivées successives de la commande et la garantie de la stabilité pour le système linéaire bouclé résultant. La première approche consiste au rajout d'un terme linéaire en commande au critère, tandis que la deuxième consiste au rajout d'une matrice de correction "intelligente" à la matrice de prédiction du critère. Quelques propriétés de la NCGPC sont données pour des systèmes SISO de degré relatif un ou deux.

2024

2024, 2006 ieee/aiaa 25TH Digital Avionics Systems Conference

In this paper, flight guidance dynamics are shown to be implicit differentially flat with respect to the inertial position of an aircraft. This proves the existence of a set of relations between these flat outputs and the state variables representative of flight guidance dynamics and between these flat outputs and the basic inputs to flight guidance dynamics. A neural network is introduced to obtain, from the actual trajectory, nominal flight parameters which can be compared with actual values to detect abnormal behaviour.

2024, Journal of Aerospace Technology and Management

The sustained increase of the air transportation sector over the last decades has led to traffic saturated situations, inducing higher costs for airlines and important negative impacts for airport surrounding communities. The efficient management of air traffic supposes that aircraft trajectories are fully mastered and their impacts can be accurately forecasted. Inversion of aircraft flight dynamics, which are essentially nonlinear, appears necessary. Aircraft flight dynamics is shown to be differentially flat, which is a property that has enabled the development of new numerical tools for the management of complex nonlinear dynamic systems. However, since in the case of aircraft flight dynamics this differential flatness property is implicit, a neural network is introduced to deal with its numerical inversion. Results related to the developed neural network training are displayed, while potential uses of the proposed tool are discussed.

2024, Aerospace Science and Technology

This paper introduces a novel auto-throttle controller designed for robust and fuel-efficient operation under changing flight conditions in four-dimensional (4D) flight trajectories (3D + time). Following typical receding horizon techniques, the throttle values are obtained by optimizing the predicted response of the system over future time intervals. The novelty is twofold: First, the controller is designed to achieve a user-defined, realistic reference value for the aircraft Specific Fuel Consumption (SFC), while maintaining the nominal safety margins during the 4D flights. Second, the throttle commands result from a closed-form expression with minimal computational effort, thus simplifying the proposed autothrottle's on-board implementation. Tests against a conventional PID-based auto-throttle illustrate the current controller's superior robustness under challenging flight conditions (turbulence).

2024

This paper aims on the evaluation of the aerodynamic derivatives from computational fluid dynamics to obtained derivatives at transonic speed. The derivatives are computed using the equation of Reynolds-Averaged-Navier-Stokes and a time-domain flow solver. In order to predict this study, standard dynamic model geometry is adopted. Three separated method is used for the calculation of aerodynamic derivatives. Then, the comparable among low-fidelity solver, high-fidelity computational and experimental data available show a satisfactory agreement was observed simultaneously. The conducted study shows the evaluation of unsteady aerodynamic derivatives prediction useful for longitudinal motion. The derivatives such as normal force derivatives and pitching moment derivatives were playing an important derivative for the aerodynamic coefficient for the dynamic motion analysis.

2024, Applied sciences

Non-linear phenomena are particularly important in -flight dynamics of micro-class unmanned aerial vehicles. Susceptibility to atmospheric turbulence and high manoeuvrability of such aircraft under critical flight conditions cover non-linear aerodynamics and inertia coupling. The theory of dynamical systems provides methodology for studying systems of non-linear ordinary differential equations. The bifurcation theory forms part of this theory and deals with stability changes leading to qualitatively different system responses. These changes are called bifurcations. There is a number of papers, the authors of which applied the bifurcation theory for analysing aircraft flight dynamics. This article analyses the dynamics of critical micro aerial vehicle flight regimes. The flight dynamics under such conditions is highly non-linear, therefore the bifurcation theory can be applied in the course of the analysis. The application of the theory of dynamical systems enabled predicting the nature of micro aerial vehicle motion instability caused by bifurcations and analysing the post-bifurcation microdrone motion. This article presents the application of bifurcation analysis, complemented with time-domain simulations, to understand the open-loop dynamics of strake-wing micro aerial vehicle model by identifying the attractors of the dynamic system that manages upset behaviour. A number of factors have been identified to cause potential critical states, including non-oscillating spirals and oscillatory spins. The analysis shows that these spirals and spins are connected in a one-parameter space and that due to improper operation of the autopilot on the spiral, it is possible to enter the oscillatory spin.

2024, Applied Sciences

2024

Computational simulations of aerodynamic characteristic s of the Common Research Model (CRM), representing a typical transport airliner, are conducted using C FD methods in close proximity to the ground. The obtained dependencies on bank angle for aerodynamic forces and moments are further used in stability and controllability analysis of the lateral-directional airc raft motion. Essential changes in the lateral-directional modes in close proximity to the ground have been identified. F or example, with approach to the ground, the roll subsidence and spiral eigenvalues are merging crea ting the oscillatory Roll-Spiral mode with quite significant frequency. This transformation of the lateraldirectional dynamics in piloted simulation may affect the aircraft responses to external crosswind, modify ha ndling quality characteristics and improve realism of crosswind landing.

2024, Bulletin of the American Physical Society

(LEAD) is a bioinspired flow control device developed based on the alula feather structure on a bird wing. In bird flight, the alula only deploys during complex maneuvers such as takeoff , landing, and perching. On an engineered wing, the addition of an alula-inspired device, such as the LEAD, enhances lift and mitigates stall at high angles of attack. Here, we explore an alula-inspired leading-edge device installed on a high-lift airfoil and a moderate aspect ratio wing. Wind tunnel experiments are conducted at post-stall and deep-stall angles of at Reynolds numbers of 100,000. Experimental results including integrated force measurements and hotwire anemometry, and PIV are discussed. We examine the distinct effects of the geometric parameters of a LEAD on the aerodynamic performance of both an airfoil and an finite wing. Results show that these lift improvements are more sensitive to the LEAD relative angle of attack and root location than to the LEAD tip deflection angle. The LEAD affects the airflow in two fundamental ways. First, it increases the capability of the wing to maintain higher pressure gradients by modifying the near-wall flow close to the leading-edge. Second, it generates tip vortices that modify the structure of the turbulence on the upper-surface of the wing, delaying flow separation

2024, Jurnal Rekayasa Mesin

The rapid growth of Unmanned Aerial Vehicle (UAV) technology, or drone, has shown its popularity and has been significantly applied to various purposes today. Nevertheless, with all the sophistication of drones, many related topics are still attractive, especially when a drone is designed to carry out a cargo mission. Thus, in this research, the dynamic model of a Hexacopter drone to deliver goods belongs to PT Aero Terra Scan is being developed. This dynamic modeling aims to further the drone's development by modeling it in 2 cases: no-payload and with a payload of 5 kg cases. The dynamic model of this Hexacopter is based on flight dynamics, a field of science studied in Aeronautical Engineering, and is implemented using Simulink. Through the results of this research, several conclusions have been withdrawn: (1) The drone's unstable nature characteristic inherently, even though it is analyzed from the initial hover condition. Thus, the drone and its system as a whole can never be separated with the feedback control that made it can maneuver adequately. (2) Several technical parameters of this Hexacopter, including the geometry, mass, the moment of inertia, until the estimation of motor throttle is required to achieve its hover conditions, both in the no-payload case and with-payload of 5 kg case. (3) The Hexacopter basic dynamic system model is based on the flight dynamics until its motion system control tuning through root locus map analysis using Simulink.

2024, arXiv (Cornell University)

This article examines the effect of Nature's common airborne forces on the flight of a small flapping organism and proposes several control strategies that could be important for all natural and engineered flight at this scale.

2024, arXiv: Fluid Dynamics

Flight is a complicated task at small scales in part due to the ubiquitous unsteady air which contains it. Flying organisms deal with these difficulties using active and passive control mechanisms to steer their body motion. Body attitudes of flapping organisms are linked with their resultant flight trajectories and performance, yet little is understood about how discrete unsteady aerodynamic phenomena affect the interlaced dynamics of such systems. In this study, we examined freely flying bumblebees subject to a single discrete gust to emulate aerodynamic disturbances encountered in nature. Bumblebees are expert commanders of the aerial domain as they persistently forage within complex terrain elements. Physical obstacles such as flowers produce local effects representative of a typified gust which threatens the precise control of intricate maneuvers. By tracking the 3D dynamics of bees flying through gusts, we determined the sequences of motion that permit flight in three disturba...

2024, Journal of Polish CIMAC

The problem described in the paper concerns the choice strategy of so-called design point of the flow engine in a multi-role aircraft at the initial stage of aircraft and engine design as the aviation system. The design point is defined by the height and speed of flight and engine parameters of heat flow which allows in particular to determine the mass and dimensions of the engine. The following analysis represents an attempt to seek other than the classic (based on a maximum within unitary thrust, specific fuel consumption) criteria for calculation point for the multi-role aircraft. Multipurpose aircraft, during every mission, very often must perform many tasks and at the same time must use the energy source for the maneuvers. The mathematical model of the chosen tasks of an aircraft has been presented, which due to the energetic requirements do not allow to build the uniform optimization criteria. The models of such flight stages have been presented: take off, climbing with the ma...

2024, Jurnal Rekayasa Mesin

2024

Artificial Neural Networks(ANN) play an important role in developing robust Knowledge Based Systems(KBS). The ANN based components used in these systems learn to give appropriate predictions through training with correct input-output data patterns. Unlike traditional KBS that depends on a rule database and a production engine, the ANN based system mimics the decisions of an expert without specifically formulating the if-then type of rules. In fact, the ANNs demonstrate their superiority when such if-then type of rules are hard to generate by human expert. Verification of traditional knowledge based system is based on the proof of consistency and completeness of the rule knowledge base and correctness of the production engine. These techniques, however, can not be directly applied to ANN based components. In this position paper, we propose a verification and validation procedure for KBS with ANN based components. The essence of this procedure is to obtain an accurate system specification through incremental modification of the specifications using an ANN rule extraction algorithm. First, the ANN based components are specified using available domain knowledge and implemented based on this specification. Next, past data sets are used to train the ANN components. An rule extraction algorithm is then applied to the trained ANN. Extracted rules are then analyzed and incrementally incorporated into the system specification. Finally. the modified specifications are verified for correctness and the product tested against the correct specifications.

2024

Experimental and modelling results for nonlinear unsteady aerodynamics of 65, 70 degree delta wings and 80 60 degree double delta wing at high angles of attack are discussed, considering the characteristic time constants approach. The research is done in the framework of a joint collaborative programme between DERA Bedford, UK and TsAGI, Russia. In this paper the current state of the work is presented.

2024

This paper focuses on the time integration of the nonlinear EOM associated with a very flexible aircraft in flight. Various integration methods exist for linear structural dynamics problems. However, a review of the literature indicates little material associated with the integration of nonlinear structural EOM of relatively large order. Moreover, for the problem of simulation of very flexible aircraft, a combination of flight dynamics and aeroelastic degrees of freedom must be solved. A modified first and second order Generalized-α Method along with an implicit sub-iteration scheme were developed. It has shown good agreement with predictor/corrector integration schemes for a reduced set of linear EOM. The method is also seen to be numerically stable when compared to non-dissipative time marching integration schemes and requires less computational time compared to predictor/corrector methods for the full set of nonlinear EOM. Recent advances in airborne sensors and communication pac...

2024, AIAA Atmospheric Flight Mechanics Conference

2024

Rudder is one of a primary flight control surface of an aircraft and have the function as directional control and directional trim. For multi-engine aircraft, critical function of the rudder is to be able to maintain aircraft direction in case of one engine inoperative. Due to aerodynamic load, the higher rudder deflection the higher hinge moment acting on the rudder. For the aircraft equipped with mechanical control system, load on the rudder can be feel by the pilot on the pedals. Excessive load received by the pilot in long duration of operation can make tired the pilot. Maximum load on the rudder allowed by regulation in VMCG with OEI is limited to 150 lbf. Current design of the rudder still produce load higher than limit value, even aerodynamic balance e.g., servo tab and rudder horn has been implemented. Sensitivity study of rudder horn balance was carried out to improve rudder hinge moment to reduce pedal force. This study was conducted by means wind tunnel testing in the NLST in Bandung, West Java. 6 rudder horn balance model was tested, the result are compared including basic or current horn design. Horn 8 provide the best result compared to basic horn and other modified horn, it is meet requirements both for load limit of 150 lbf and safety aspect.

2024, INCAS Buletin

2024

Hannibal Barca Weren't there times when everybody, or at least a few people, just panicked? No, when bad things happened, we just calmly laid out all the options, and failure was not one of them. We never panicked, and we never gave up on nding a solution. Résumé de Thèse vii Table of Acronyms xxv Nomenclature xxvii Résumé de Thèse xv Conclusions et Perspectives Cette thèse a étudié l'utilisation des techniques à paramètres linéaires variant (LPV) pour la modélisation et la conception de contrôle d'un nouveau concept de projectile guidé à longue portée (LRGP). Le développement d'une munition à portée étendue vise à combler l'écart technologique entre les projectiles balistiques/guidés lancés par canon standard et les applications de missiles à propulsion par fusée plus sophistiquées. Une contribution importante réside dans la caractérisation de la dynamique de vol/aérodynamique du nouveau concept de projectile et dans la proposition d'une procédure complète dédiée à la reformulation du modèle LPV. De plus, l'utilisation réussie de diérentes approches de conception de contrôle basées sur LPV (polytopique, basée sur grille) a conrmé les avantages fournis par le cadre LPV pour ces technologies spéciques, malgré la quantité limitée d'applications proposées dans la littérature. Les résultats obtenus à travers les processus de modélisation LPV et de conception de contrôle suggèrent également plusieurs points d'amélioration possibles : ❖ Régression Aérodynamique : Le modèle aérodynamique pourrait être davantage développé en exploitant la dépendance des coecients aérodynamiques par rapport à la variation de Mach. ❖ Variables de Référence : Le choix de l'angle d'attaque aérodynamique (AoA) comme variable de planication représente un choix assez inhabituel car des mesures précises nécessitent une instrumentation dédiée. La reformulation du modèle de vol du projectile en termes de dynamique d'accélération pourrait simplier le processus de mise en ÷uvre. ❖ Approche de Modélisation LPV : Des techniques de modélisation alternatives pourraient être envisagées pour assouplir les contraintes imposées par l'approche de transformation d'état. ❖ Dénition du Polytope : Une reformulation de la forme du polytope pourrait améliorer les performances de la conception du contrôle. Cela pourrait être réalisé en changeant de variables, en dénissant le polytope autour de la trajectoire prévue du projectile. ❖ Sélection de la Grille : L'utilisation des fonctions MATLAB LPVTools pour la conception impose la dénition d'une grille rectangulaire/cubique, ce qui peut entraîner l'inclusion de conditions de vol indésirables. Une reformulation appropriée du problème d'optimisation des LMI pourrait permettre de relâcher les contraintes de forme imposées par LPVTools.

2024, HAL (Le Centre pour la Communication Scientifique Directe)

2024

The purpose of this paper is to analyze the influence of aircraft vertical landing speed (sink speed) and horizontal landing speed (approach speed) on amount of energy absorbed by shock absorber that equipped a landing gear with trailing arm. A landing gear multibody model was built by using Virtual Lab software which makes possible to simulate drop test runs in order to check the speeds effects. The model allows setting different initial conditions and computing the amount of absorbed energy from each run. Settings and results from each drop will be analyzed according to 2k Factorial Design in order to determine the factors (speeds) effects as well as the interaction between them.

2024

Unmanned Aerial Vehicle become popular and very useful today. Unmanned Aerial Vehicle types have fixed wing UAV and rotary wing UAV. Among rotary wing UAV, helicopter type is chosen to implement the mathematical model for UAH. Since these helicopter mathematical model is very complex and inflexible, simple model "minimum-complexity helicopter simulation math model" (MCHSMM) is used to develop a non-linear mathematical model R-50 helicopter for this work. This modeling consists of three blocks: (1) Rigid body dynamics, (2) Force and torque dynamics, and (3) Flapping and thrust dynamics. Each of these are implemented in MATALB SIMULINK. There are four control inputs: ulat (lateral control input), ulong (longitudinal control input), ucol (collective control input) and uped (pedal control input). By alternating positive, negative, and zero to four control inputs, the resultant responses of positions, Euler angles, translatory velocities, angular velocities and flapping angles ...