Wyniki wyszukiwania - BazTech

1

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

Czekałowski P., Sibilski K., Żyluk A.

Journal of KONES

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2018

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Vol. 25, No. 4

49--57

EN

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.

2

A conception of vertical take-off air vehicle with self-aligning moving wings

Lichoń D.

Journal of KONES

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2014

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Vol. 21, No. 4

311--317

EN

The possibility of vertical take-off of an aircraft is a valuable feature in air transport. It allows to increase operational characteristics of an air vehicle and requires less field and low cost ground infrastructure. Currently the vertical take-off feature is practically reserved to helicopters and tilt-rotor aircrafts. Both types of air vehicles have their advantages and also have some important limitations. Regarding the helicopters their construction provides natural vertical take-off features and makes them useful in low altitude flight tasks. However the power required for flight and main rotor kinematics results in low cruising speed and short range performance. The tilt-rotor aircraft is an answer which provides good cruise characteristics saving the vertical take-off feature. The construction of tiltrotor aircraft consists of rotors with adjustable position of tip-path plane. The main technical problem of tilt-rotors is necessity of change aerodynamic configuration from vertical mode to cruise mode at low flight altitude and very low flight speed. A proposed conception of a vertical take-off air vehicle using self-aligning moving wings is focused on producing aerodynamic force always on wings without participation of rotors or propellers. The self-aligning or semirotating wing movement enables to produce aerodynamic force in each flight speed. During take-off lift force is generated by means of power unit driving the wings. The transition from hovering to progressive flight is a smooth phase without aerodynamic configuration changes. It occur as a result of change in wing kinematics or gravity center position. As the flight speed increases the lift force is generated like in classic airplane wing and the power unit load decreases. The conception of presented air vehicle assume to join best features of airplanes and helicopters i.e. vertical take-off, good flight performances and lack of strict border between both phases of flight.

3

Microelectromechanical flying robots - state of the art

Sibilski K.

Acta Mechanica et Automatica

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2008

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Vol. 2, no. 2

75-88

EN

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.

4

Experimental investigation of aerodynamic forces generated on ornithopter model in wind tunnel.

Wojciechowski J.

Archive of Mechanical Engineering

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2002

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Vol. XLIX, nr 3

271-290

EN

The measurement of lift and drag forces on the ornothopter model with flapping wings was carried out in the wind tunnel. The wing movement had two degrees of freedom: flapping (around the longitudinal axis of the model) and feathering (around the wing axis). Forces were measured in static case - as averaged values during many cycles of movement, and in dynamic case - as unsteady forces captured in function of the flapping phase. The magnitudes of the aerodynamic coefficients of lift and drag were calculated.

PL

Wykonano badania eksperymentalne w tunelu aerodynamicznym, obejmujące pomiary siły nośnej i siły oporu na modelu ornitoptera z ruchomymi skrzydłami. Skrzydła wykonywały ruch o dwu stopniach swobody: machanie (wokół osi podłóznej modelu) i przekręcanie (wokół osi podłużnej płatów). Mierzono siły w układzie statycznym - uśredniając pomiar w czasie kilkudziesięciu cykli ruchu, jak również w układzie dynamicznym, mierząc siły nieustalone na płatach w funkcji fazy ruchu. Obliczono odpowiednie wartości współczynników siły i oporu aerodynamicznego.

5

Manewry przechylające animalopterów bez lotek

Marusak A., Pietrucha J., Sibilski K.

Zeszyty Naukowe Katedry Mechaniki Stosowanej / Politechnika Śląska

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2001

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z. 15

227-231

PL

Omawiana jest możliwość kształtowania sprężystych skrzydeł machających w celu wykonywania manewru przechylania w szerokim zakresie ciśnień dynamicznych, ale bez użycia lotek. Zaproponowano w tym celu dwie metody: 1) technikę sterowania łopatą wirnika nośnego śmigłowca; 2) metodę opartą na kinematyce mechanizmu wieloczłonowego. W metodzie pierwszej skręcanie sprężyste realizowane jest za pomocą piezoelektryków umieszczonych w strukturze skrzydła, które mają generować odpowiednie siły sterujące. W metodzie "kinematycznej" pożądany kształt skrzydła uzyskuje się poprzez dobór odpowiednich połączeń struktury skrzydła.

EN

An approach of deforming a flexible flapping wing to achieve a specified roll rate at dynamic pressures without ailerons is examined. To achieve this goal the two following methods are proposed: 1) the elastic twist is achieved by providing a system actuating elements distributed within the internal substructure of the wing to provide control forces; 2) a method based on a multibody system's kinematics. In the first method piezoelectric elements have been extensively used to control the shape of a beam. In the "kinematic" method the desired shape of the wing is achieved by choosing proper connections of the wing structure.