Dynamics of Micro-Air-Vehicle with Flapping Wings

Small (approximately 6 inch long, or hand-held) reconnaissance micro air vehicles (MAVs) will fly inside buildings, and require hover for observation, and agility at low speeds to move in confined spaces. For this flight envelope insect-like flapping wings seem to be an optimal mode of flying. Investigation of the aerodynamics of flapping wing MAVs is very challenging. The problem involves complex unsteady, viscous flow (mainly laminar), with the moving wing generating vortices and interacting with them. At this early stage of research only a preliminary insight into the nature of the little known aerodynamics of MAVs has been obtained. This paper describes computational models for simulation of the controlled motion of a microelectromechanical flying insect – entomopter. The design of software simulation for entomopter flight (SSEF) is presented. In particular, we will estimate the flight control algorithms and performance for a Micromechanical Flying Insect (MFI), a 80–100 mm (wingtip-to-wingtip) device capable of sustained autonomous flight. The SSEF is an end-to-end tool composed of several modular blocks which model the wing aerodynamics and dynamics, the body dynamics, and in the future, the environment perception, control algorithms, the actuators dynamics, and the visual and inertial sensors. We present the current state of the art of its implementation, and preliminary results.

Studium dynamiki lotu śmigłowca z podwieszonym ładunkiem z wykorzystaniem teorii bifurkacji i metod kontynuacyjnych

The paper presents a study of the flight dynamics of a helicopter with an articulated rotor, carrying a suspended load. The aircraft model includes rigid body dynamics, individual flap and blade dynamics, and inflow dynamics. The load is a point mass with a single suspension point. Results are obtained for load masses of up to 1500 kg, with load-to-helocopter mass rations up to 33%, and cable lengths up to 55m. The presence of the external load modifies the flight dynamics and handling quality characteristics of the helicopter because the dynamic and aerodynamic characteristics of the load may make it unstable in certain fight conditions. Maneuvers of this system in wide flight regimes involves non-linear aerodynamics and inertial coupling. In can be stated that the helicopter with the suspended load is a inherently non-linear and time varying system. Theory of dynamical systems provides a methodology for studying such non-linear systems. Bifurcation theory is a part of that theory. It considers changes in the stability of the system which lead to qualitatively different responses of it. In this paper, results from the theory of dynamical systems are used to predict the nature of instabilities caused by bifurcations and the response of the rotorcraft with the suspended load that follow such bifurcations.W pracy przedstawiono studium dynamiki lotu śmigłowca z przgubowym wirnikiem nośnym, przenoszącego podwieszony pod kadłubem ładunek. W zastosowanym modelu wiropłata uwzględniono stopnie swobody nieodkształcalnego kadłuba, dynamikę wahań i odchyleń łopat wirnika nośnego oraz dynamikę przepływu przez płaszczyznę wirnika nośnego. Założono, że podwieszony ładunek jest punktem materialnym, na który działają siły aerodynamiczne, podwieszonym w jednym punkcie pod kadłubem śmigłowca. Wyniki obliczeń uzyskano dla podwieszonych ładunków o masie do 1500kg (stosunek masy ładunku do masy śmigłowca do 35%), podwieszonych na linie o długości do 55m. Obecność podwieszonego ładunku modyfikuje charakterystyki dynamiczne i osiągi śmigłowca ze względu na silne sprzężenia aerodynamiczne i bezwładnościowe pomiędzy jego ruchem a ruchami śmigłowca. Ze względu na fakt, że układ śmigłowiec-podwieszony ładunek jest opisany za pomocą silnienieliniowych zwyczajnych równań różniczkowych, zastosowanie klasycznej analizy modalnej układu nie zawsze jest możliwe. Doskonałych narzędzi do badania takich równań dostarcza teoria układów dynamicznych i będąca jej częścią teoria bifurkacji. W pracy wykorzystano metodologię teorii układów dynamicznych do prognozowania natury niestabilności spowodowanej występującymi bifurkacjami. Ponadto przeprowadzono symulacje ruchu układu śmigłowiec-podwieszony ładunek po wystąpieniu bifurkacji

On application of dynamical systems theory into inwestigation of critical flight regimes of flying vehicles

Non-linear dynamics phenomena have become important for various aircraft motions. Manoeuvrability of an aircraft in critical flight regimes involes non-linear aerodynamics and inertial coupling. Dynamical systems theory provides a methodology for studying non-linear systems of ordinary differential equations. Bifurcation theory is a part of that theory which is considering changes in the stability, which lead to qualitatively different responses of the system. These changes are called bifurcations. The mathematical models used in the paper assume a rigid aircraft with movable control surfaces, and "invidual blade" rotorcraft model. Aerodynamic model includes also a region of higher angles-of-attack including deep stall phenomena. In the present paper, the wing-rock oscillations, and helicopter spin(i.e. intensive spiral glide motion) was studies by means of checking the stability characteristics related to unstable equilibria. Numerical simulations were used to verify the predictions. Wing-rock oscillations were studied to observe the chaos phenomenon in post-stall manoeuvres. Unsteady aerodynamics for prediction of the airfoil loads was included, and the ONERA-type stall model was used.Zastosowanie teorii systemów dynamicznych do badania krytycznych stanów lotu statków powietrznych. Ruch statku powietrznego jest opisywany za pomocą układu silnie nieliniowych równań różniczkowych zwyczajnych. Zlinearyzowanie równania ruchu nie mogą być zastosowane do opisu wielu zagadnień dynamiki lotu. Teoria systemów dynamicznych pozwala na efektywne badania nieliniowych równań różniczkowych. Teoria bifurkacji, będąca częścią teorii systemów dynamicznych, umożliwia badanie zmian stateczności, które ptowadzą do jakościowo różnych odpowiedzi systemu. Założono, że statek powietrzny jest nieodkształcalny. Uwzględniono stopnie swobody ruchomych powierzchni sterowych oraz łopat wirnika nośnego. Przyjęty model aerodynamiczny umożliwia uwzględnienie zjawiska głębokiego przeciągnięcia dynamicznego oraz niestacjonarności opływu(histereza współczynników aerodynamicznych). Za pomocą metodyki teorii systemów dynamicznych rozpatrzono osobliwości niestateczności typu wing-rock i tzw. "korkociągu" śmigłowca. W celu zweryfikowania przewidzianych niestabilności przeprowadzono cyfrową symulację tych ruchów. Zaobserwowano nieregularność rozwiązań charakterystycznych dla ruchów chaotycznych

Numerical investigation into flight dynamics of an agile aircraft

The aim of this study is to prove practical applicability of a numerical simulation technique in highlights some of the features of the flight under extreme conditions. dynamics of spatial motion of an agile aircraft is considered. After a brief description of an aircraft mathematical model, the numerical analyses are presented. There have been considered various flight events (such as airdrop or aircraft accident) and manoeuvres (in particular, those performed at high angles of attack).Numeryczne badanie dynamiki lotu samolotów o podwyższonej sterowności. Rozpatrzono dynamikę samolotu o podwyższonej sterowności. Badania prowadzono stosując symulację komputerową. Zaprezentowano wyniki dynamiki ruchu samolotu w różnych stanach lotu i manewrach

Microelectromechanical flying robots - state of the art

Micro Air Vehicles (MAVs) are miniature airplanes constructed from state-of-the-art materials, designed to be small, light, and highly resilient. Current applications include surveillance, reconnaissance, and munitions. Many of the planes, because of their size, have unconventional designs with respect to the wings and control surfaces. Instability introduced by the small non-traditional aircraft designs must be addressed, to eliminate the need for an expert pilot for aircraft control and navigation. In this paper we present a state-of-the-art technology development focused on the technologies and components required to enable flight at small scales, including flight control, power and propulsion, navigation, multi-purpose structures, advanced communications and information systems, Micro-electro-mechanical Systems (MEMS), advanced sensors, and lightweight, efficient high-density power sources

Optimisation of aircraft position in the formation flight for the drag reduction

This article presents optimisation of necessary flight thrust in a V-shaped flight formation of small-unmanned plane “Sikorka”. At the beginning is showed analyse of birds behaviour. Their formation flying was the cause of attention in order to minimalize fuel consumption. Afterwards there are overlooked scientific articles about the formation flying subject contain pure physic analyses, and articles about researches which was made in order to explain economic beneficial for airlines. Thus, the article presents mathematical model, which was optimised for three different starting position of a longitudinal axis. After optimisation there are presented results of the wingman position in regard of the leader. Influence of the calculation results on the formation flying was analysed, allowing for some conclusions about the future of the UAV’s flights. The given process is aimed to achieve the best (optimal) solution from the point of view of the specific criterion. The following most important terms can be distinguished within the optimization process: decisive variables – parameters determining the basic project assumptions. The basic design variables and design constrains are described

Prediction of aircraft lost of control in the flight by continuation, bifurcation, and catastrophe theory methods

Lost of Control in Flight (LOC-I) is ordinarily associated with flight outside of the normal flight envelope, with nonlinear behaviours, and with an inability of the pilot to control the aircraft. These results provide a means for analysing accident data to establish whether or not the accident should be classified as LOC-I. Moreover, they help identify when the initial upset occurred, and when control was lost. The analysis also suggests which variables were involved, thereby providing clues as to the underlying mechanism of upset. However, it does not provide direct links to the flight mechanics of the aircraft, so it cannot be used proactively to identify weaknesses or limitations in the aircraft or its control systems. Moreover, it does not explain how departures from controlled flight occur. The complexity of the disaster aetiology stems from both the scale and coupling of the systems (not only the physical aircraft systems but also the organizational systems that support the operation). This complexity creates a pattern of disaster that evolves or it is precipitated through a series of several small failures. The cusp catastrophe model facilitates the mapping of Reason’s latent failure model, providing a descriptive and predictive illustration of the emergence of latent conditions under the trigger of situational factors. The risk of an accident increases as the situational and systematic factors combine to create an inherent instability resulting in the catastrophic event

Biologicznie inspirowana stabilizacja zawisu mikrosamolotu napedzanego machającymi skrzydłami

MA V flight stability and control presents some difficult challenges. The low moments of inertia of MA Vs make them vulnerable to rapid angular accelerations, a problem further complicated by the fact that aerodynamic damping of angular rates decreases with a reduction in wingspan. Another potential source of instability for MA Vs is the relative magnitudes of wind gusts, which are much higher at the MA V scale than for larger aircraft. In fact, wind gusts can typically be equal to or greater than the forward airspeed of the MAV itself. Thus, an average wind gust can immediately affect a dramatic change in the vehicle's flight path. Other problem occurs with influence of flapping wings on MA Vs body motion. The birds and flying insects, the biological counterpart of mechanical MA Vs, can offer some important insights into how one may best be able to overcome these problems. Biological systems, while forceful evidence of the importance of vision in flight, do not, however, in and of themselves warrant a computer-vision based approach to MA V autonomy. Fundamentally, flight stability and control requires measurement of the MA Vs angular orientation. While for larger aircraft this is typically estimated through the integration of the aircraft's angular rates or accelerations, a vision-based system can directly measure the MA Vs orientation with respect to the ground. The two degrees of freedom critical for stability the bank angle and the pitch angle can be derived from a line corresponding to the horizon as seen from a forward facing camera on the aircraft. Therefore, we have developed a vision-based horizon-detection algorithm that lies at the core of our flight stability system.Celem pracy było opracowanie koncepcji detekcji położenia przestrzennego mikrosamolotu z machającymi skrzydłami (tzw. entomoptera) oraz przeprowadzenie szeregu eksperymentów numerycznych z wykorzystaniem modelu symulacyjnego. Koncepcja sterowania była inspirowana metodą wykrywania położenia przestrzennego spotykaną u owadów. Wiele gatunków owadów swoją orientację przestrzenną ustala wykorzystując organ zwany przyoczkami. Przyoczka są rodzajem czujników optycznych. Czujniki te łatwo zamodelować przy pomocy czterech fotodiod umieszczonych na piramidalnym statywie. Fotodiody te mierzą natężenie światła w otoczeniu owada. W pracy przedstawiono uproszczony model matematyczny entomoptera, oraz zaprezentowano rozważania dotyczące efektywności detekcji położenia za pomocą pomiaru natężenia światła. Podano także matematyczny model przyoczek. Następnie przedstawiono wyniki badań symulacyjnych dowodzących efektywności przyoczek. Symulacje prezentujące przebiegi odpowiednich sygnałów przeprowadzono wykorzystując program MATLAB

Experimental study and neural network modelling of aerodynamic and dynamic characteristics of flapping wings micro aerial vehicle

The article is close connected with building flying object, that fly like an insect (entomopter). Present work concerns on concept of aerodynamic model using artificial neural networks. Model is used in simulations of flight of entomopter. Aerodynamic model based on experimental data. Necessary data are taken from experiment performed in water tunnel on entomopter model. For this case dynamic test are required. Measurements are ducted during sinusoidal motion of whole model. Modelled object is dipterous. Each wing can perform various spherical motions (wing is rotated around point). The motion of the wing in this case was two-dimensional; it was rotated around two axis. As a model, specially trained neural network is used. For training are used data from measurement. Presented in this article approach is based on artificial neural networks. In this article, innovative concept of model, describing unsteady aerodynamics of entomopter was proposed. It was shown that it could be easily implemented as mathematical model. Unsteady effects related to many state variables can be easily captured. Model can be easily adopted to predict different states of flight by networks training on appropriate data. Test has to reproduce real conditions as close, as it is possible. In reality, it is challenging to design test that will reproduce similar motion

Development of mathematical model for the autonomous gliding delivery system

For parafoil and payload aircraft, control is affected by changing the length of several rigging lines connected to the outboard side and rear of the parafoil leading to complex changes in the shape and orientation of the lifting surface. Flight mechanics of parafoil and payload aircraft most often employ a 6 or 9 DOF representation with the canopy modeled as a rigid body during flight. The effect of control inputs usually is idealized by the deflection of parafoil brakes on the left and right side of the parafoil. This work focused on description of a 9 DOF parafoil and payload aircraft simulation model