Andrzej Zyluk

MODELING AND SIMULAT ION OF THE NONLINEAR DYNAMIC BEHAVIOR OF A FLAPPING WINGS MICRO - AERIAL - VEHI CLE

This paper describes nonli near computational model for the simulation of co ntrolled motion of flapping wings Micro Air Vehicle. The following assumptions are made: the motion of wings are d ecomposed into flapping, lagging, and feathering rot ations; each wing is rigid and rotates ab out the co mmon axis; aerod ynamic forces coming from airfoils have periodical character; the wing vortices are ge nerated at the trai ling edge only; the shape of the wake is determined from calc ulations via a time -stepping procedure. Because of highly nonlin ear dynamics of flapping wings MAVs over the flight env elope, the state space formulation with the linearized equ ations of motion is not sufficient to describe the co upled dynamics of those vehicles. Therefore, a model with the complete nonlinear different ial equations of m otion and nonlinear aerodyna mics is derived.

Influence of Cruise Flight Speed of Entomompter on Aerodynamics Loads

Przedstawiony artykul ściśle nawiązuje do prac nad stworzeniem obiektu latającego, ktory generuje sile nośną tak jak latające owady, czyli entomoptera. Przedstawiona praca dotyczy badan doświadczalnych prowadzonych na mechanizmie trzepoczącym pracującym w tunelu wodnym. Obiekt wyposazony jest w dwa skrzydla. Kazde z nich moze wykonywac dowolny ruch kulisty (obrot wokol punktu). Celem pracy bylo wyznaczenie maksymalnych predkości lotu i uzyskiwanych wartości sil nośnych obiektu dla roznych sposobow ruchu skrzydel. Eksperyment polegal na pomiarze sil hydrodynamicznych generowanych przez obiekt za pomocą wagi tensometrycznej. Ruch skrzydel odbywal sie w jednej plaszczyźnie. Parametrami doświadczenia byly predkośc postepowa oraz kąt pochylenia plaszczyzny trzepotania. Uzyskane wyniki pozwalają na przewidzenie maksymalnej predkości lotu rzeczywistego obiektu dla zadanego udźwigu, wskazują ewentualne sposoby poprawy osiągow. Dają rowniez istotne informacje z punktu widzenia mechaniki lotu, a konkretnie stateczności podluznej ukladu trzepoczącego. Artykul oprocz analizy wynikow eksperymentu zawiera takze opis metodologii pomiarow

Biomimic Sensors Guided Flight Stability and Control for Flapping Wings Autonomous Micro Air Vehicles (Entomopter)

MAV flight stability and control presents some difficult challenges. The low moments of inertia of MAVs 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 MAVs is the relative magnitudes of wind gusts, which are much higher at the MAV 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 MAV’s body motion. The birds and flying insects, the biological counterpart of mechanical MAVs, 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 MAV autonomy. Fundamentally, flight stability and control requires measurement of the MAV’s 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 MAV’s orientation. Most of the fly’s neural processing is devoted to vision, and its compound eyes are the key to flight control. Also notable are three light sensitive sensors arranged in a triangle on the top of the head, called ocelli. Research on insect flight revealed that in order to maintain stable flight, insects use structures, called halteres, to detect body rotations via gyroscopic forces. Therefore, we have developed a control system based on mathematical models of ocelli and halteres. We have developed algorithms based on vision and gyroscopic forces detection, and developed simulation tool provides a basis for an advanced description of an entomopter stabilization and dynamic behaviour.

An Inverse Simulation Study on Wing Adapter Kit Dynamics and Control in Prescribed Trajectory Flight

*† This paper presents a uniform approach to the modeling and simulation of smart Winged Adapter Kit (WAK) trajectory flight. WAK is a device that includes a pair of controllable wings which, after bolting onto the standard, general purpose bomb, transforms the weapon from a ballistic chunk of iron into a targetable stand-off glide bomb, thus creating a sophisticated Precision Guided Munitions (PGM) gliding bomb. The WAK motion is specified by a trajectory in space, a condition on a winged bomb attitude with respect to the trajectory, and a desired flight velocity variation. For a WAK controlled by aileron, elevator and rudder deflections changes, a tangent realization of trajectory constraints arises, which yields two additional constraints on the airframe attitude with respect to the trajectory. By combining the program constraint conditions and bomb dynamic equations, the governing equations of programmed motion are developed in the form of differential-algebraic equations. A method for solving the equations is proposed. The solution consists of time variations of the aircraft state variables and the demanded control that ensures the programmed motion realization.

Sensitivity Analysis for Dynamic Models of Aerial Munitions

*† While investigating dynamic properties of aerial bombs, both the analytical and experimental outcome often find their applications. Analysis of how a series of changes in flight parameters affect flight dynamics is probably one of the most essential efforts throughout this study. Numerical solutions of equations of motion deliver no information on the effect of changes in the aerial bomb’s design parameters on flight characteristics thereof. Therefore, the theory of sensitivity has been used in the paper to investigate the effect(s) of external disturbances, drop/release conditions and technical parameters on the aerial bomb’s range and flight path.

Simulation studies of micro air vehicle

In the paper, we presented results of analysis of Micro Air Vehicle MAV stability on high Angle of Attack (AOA) by application continuation methods and bifurcation theory. Moreover, it presented two main tasks accomplished – performance analysis carried out, as well as numerical studies in order to find possible simplifications drive model, suitable for further design and analysis. This paper shows the typical MAV construction and their characteristics. Then presented results of calculations of necessary and required power (for CR3516 motor). The results shown in the Figure. The next step of MAV performance examination was calculations of dynamics stability and controllability of open loop system. Also shown state, and control matrixes for the longitudinal motion. Roots loci and open loop dynamics analysis for longitudinal motion are shown in the Figures. The next shown few function such as transfer function for the input (longitudinal velocity), transfer function for the pitch angular rate q input and for the lateral motion, state, and control matrices, etc. At the end shown results of simulations for dynamic response of MAV flight disturbance is shown in the Figure. The paper concluded short motions.

Aerodynamic measurements micro air vehicle

In present times, constructions of micro air vehicles arouse more and more interest researchers and manufacturers. Air turbulence is perceived as a major problem for Micro Air Vehicles (MAV) in outdoor applications. According to the literature, short duration vertical gusts may have velocity comparable to MAV airspeed, so brief periods of flight at very large angles of attack have to be considered. In these circumstances, it seems reasonable to apply the design with as high stall angle of attack as possible. In particular, the flow has to be attached to control surfaces to perform effective control in order to damp air turbulence effect. Therefore, an aircraft configuration was developed with cranked delta wing and propeller located inside the wing contour. To prove the value of the concept, wind tunnel experiment was undertaken. The prototype demonstrated ability to fly controllably at extremely high angles of attack. Moreover we present few disadvantages of these construction for example it was very sensitive to the motor settings, since every rpm change required immediate airplane trimming to maintain straight path of flight. This drawback can be eliminated by application of counter-rotating propeller. The status of the program is presented in the paper, including the most recent results, as well as currently undertaken experiments and plans for the nearest future.

Water Tunnel Experimental Studies of Leading Edge Vortex Control on Delta Wing MAV

It is known, that small disturbances generated by the micro actuators can alter largescale vortex structures, and consequently, generate appreciable aerodynamic moments along all three axes for flight control. In the current study, we explored the possibility of independently controlling these moments. We perform analytical simulations showing optimal position of LEX generators, and water tunnel measurements showing effectiveness of MEX generators as MAV control devices. We applied array of actuators located on either the forward or the rear half section of the leading edge. Both one- and two-sided control configurations have also been investigated. Experimental results showed that asymmetric vortex pairs were formed, which leads to the generation of significant torques in all three axes’.

Studies and tests of micro aerial vehicle during flight

The article presents the results of flight tests of an unmanned flying device based on a model Micro Air Vehicle (MAV). The airplane was used during experimental studies. In the article, on-board equipment of micro-plane used in the study has been shown. Furthermore, the process of integrating all of the avionics equipment with MAV has been described. During the flight test, all parameters of microaircraft flight such as air and cruising speeds, altitude, air route, angles of tilt, slope angle, deviation angle, tilting speed, slope speed, deviation speed, etc. were recorded. During the study, the behaviour of micro-aircraft in various phases of flight such as autonomous take off, landing, programmable flight to the specific points of the air route was checked. In addition, the action of specified fail safe features of micro airplane operating in the case of a failure (e.g. in the case of low voltage of power package, loss of GPS signal, loss of communication with the ground station, etc.) is determined. The graphs of some flight parameters and figures of flight routes as well as flight profiles during the programmable flight have been presented. The researches allow for the verification of the integration process of micro-aircraft with on-board systems and they also allow for evaluation of its functional characteristics in further studies such as formation flights and bypassing the obstacles.

Estimation of MAV Unsteady Aerodynamic Parameters From Dynamic Water Tunnel Testing

Improved aerodynamic mathematical models, for use in MAV flight control design, are required when representing nonlinear unsteady aerodynamics. A key limitation of conventional aerodynamic models is the inability to map frequency and amplitude dependent data into the equations of motion directly. In an effort to obtain a more general formulation of the aerodynamic model, researchers have been led to a parallel requirement for more general testing methods. Testing for a more comprehensive model can lead to a very time consuming number of tests especially if traditional single frequency harmonic testing is attempted. This paper presents an alternative to traditional single frequency forced-oscillation testing by utilizing Schroeder sweeps to efficiently obtain the frequency response of the unsteady aerodynamic model. Schroeder inputs provide signals with a flat power spectrum over a specified frequency band. For comparison, experimental results using the traditional single-frequency inputs are also considered. A method for data analysis to determine an adequate unsteady aerodynamic model is presented. Discussion of associated issues that arise during this type of analysis and comparison of results using traditional single frequency analysis are provided.