Wyniki wyszukiwania - BazTech

1

Low altitude control for quadcopter using visual feedback

Urbański Konrad

Archives of Electrical Engineering

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2021

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Vol. 70, nr 4

845--858

EN

The paper presents the results of simulations and experiments in the field of control of the low damping and time delay oscillating system. This system includes a quadcopter hovering at a very low altitude, and the altitude is controlled. The time delay is introduced mainly by the remote control device. In order to handle the quadcopter at low altitudes, a proportional-integral controller with a negative proportional coefficient is used. Such an approach can provide good results in the case of an oscillating, low damped system. This method of steering, which uses a typical radio control transmitter, can be used on any commercially available leisure drone. Feedback is provided by a camera and algorithms of computer vision. The presented results were obtained experimentally using free flight–without a harness. Different types of controllers are used to control horizontal shift and altitude.

2

Ground effect influence on the aerodynamic characteristics of ultralight high-wing aircraft : wind tunnel tests

Placek R., Ruchała P., Stryczniewicz W.

Journal of KONES

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2017

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Vol. 24, No. 2

183--190

EN

The ground proximity may significantly improve the performance of the aircraft, but in some conditions, it affects its stability. The gain of lift which and reduction of drag during low altitude flight is known as the wing in ground effect (WIG effect). It may concern aircrafts or WIG-crafts (ground effect vehicles). In the article experimental results of the wind tunnel test of an aircraft in ground effect has been presented. The main aim of the test was to investigate the ground effect influence on aerodynamic characteristic of the of the ultralight high-wing aircraft model during early take off, taxiing or final landing stage. Investigation was carried out in the 1.5 m diameter low speed T-1 wind tunnel in the Institute of Aviation in Warsaw. The velocity was 32 m/s and Reynolds number related to the aerodynamic chord was equal about 0.37·106. Tests were performed for chosen angles of attack in range 0-10⁰. During investigation, the strain gauge balance measurements and Particle Image Velocimetry (PIV) flow visualization technique were applied. Tested model position was relatively close to the ground. It was found, that the ground proximity has significant influence on the pitching moment. The normal force was increased and the axial force is decreased due to the WIG effect, which is compatible with the theory. It has significant meaning for control aircraft issue and safety.

3

Numerical Investigation of the Wing-in-Ground Effect on Aerodynamic Characteristics

Wrzesień S., Frant M., Majcher M.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2016

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Vol. 7, Nr 4 (26)

115-130

EN

This paper presents the numerical evaluation of ground (proximity) effects on the basic aerodynamic characteristics of a specifically designed airplane model. The ground effects were investigated in relation to the angle of attack and flight altitude. The results were referenced to the characteristics of an object in motion unaffected by ground effects.

PL

W pracy przedstawiono badania numeryczne wpływu efektu bliskości ziemi na podstawowe charakterystyki aerodynamiczne specjalnie do tego celu zaprojektowanej bryły samolotu. Zbadano wpływ bliskości ziemi w zależności od kąta natarcia oraz w zależności od wysokości lotu. Wyniki odniesiono do charakterystyk obiektu poruszającego się bez efektu bliskości ziemi.

4

Available search effort of the WIG craft

Górtowska M.

Zeszyty Naukowe / Akademia Morska w Szczecinie

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2012

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nr 29 (101)

30-36

EN

The article addresses an issue of expansion of maritime rescue systems with new components which are Wing-In-Ground-Effect Crafts (WIG craft). Due to operational characteristic, use of phenomenon of ground effect, WIG crafts are extremely economical and achieve relatively high speeds. In addition, they possess also amphibious features. This represents a huge potential for participation in search and rescue actions. The article discusses the phenomenon of a ground effect and its operation performance benefits and limitations. The applications of the WIG craft for specific actions such as conducting search, medical transport, supply of equipment and crews, patrolling are specified. The article analyzes the Search Effort of the WIG craft and marine search unit SAR-1500, actually used on Polish coast. The study consists in determining the relationship between the altitude of the observer, his speed and search width. Next the calculation of available search effort is conducted. The results enable to compare the ability of different types of the patrol units.

PL

Artykuł porusza kwestię rozbudowy morskich systemów ratowniczych o nowe komponenty, jakim są ekranoplany (jednostki WIG). Ze względu na charakter operacyjny, czyli wykorzystywanie zjawiska efektu przypowierzchniowego, ekranoplany są niezwykle ekonomiczne oraz uzyskują relatywnie duże prędkości. Dodatkowo wyróżniają się cechami amfibijnymi. Stanowi to o ich ogromnym potencjale możliwości udziału w akcjach poszukiwawczo-ratowniczych. W artykule omówione zostaje zjawisko efektu przypowierzchniowego oraz wynikające z niego korzyści i ograniczenia eksploatacyjne. Wyszczególnione zostają także możliwości zastosowania ekranoplanu do konkretnych działań, takich jak prowadzenie poszukiwań, transport medyczny, dostarczanie sprzętu i ekip, patrolowanie etc. W artykule przeprowadzono analizę wydajności poszukiwawczej ekranoplanu oraz obecnie stosowanej na polskim wybrzeżu jednostki ratowniczej SAR-1500. Badanie polega na wyznaczeniu zależności między wysokością położenia obserwatora i jego prędkością a szerokością pasa poszukiwań oraz obliczeniu dostępnej wydajności poszukiwawczej. Wyniki analizy pozwalają na porównanie osiągów różnych typów jednostek patrolowych.

5

A study on performance of planing-wing hybrid craft

Hamid Zeraatgar Hamid, Ali Bakhshandeh Rostami Ali Bakhshandeh, Abolfazl Nazari Abolfazl

Polish Maritime Research

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2012

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nr 4

16-22

EN

A hybrid craft is defined as a combination of different lifting surfaces. The lift force can be of aerodynamic or hydrodynamic character. This research deals with the conditions of using planing mono-hulls equipped with a couple of wings, called planing-wing hybrid craft. A parametric study is conducted by using Vortex Lattice Method to determine feasibility of using an aerodynamic wing mounted to planing craft. It has been determined that the wing area should be more than twice as much as the wetted surface of the craft, to get an effective wing for planing craft. Furthermore, the wing should be so designed as to obtain its high aspect ratio. Maximum lift force contribution resulting from different wing configurations considered in this study is less than 35 percent of the total hydrodynamic lift force at an arbitrary condition. On this basis it may be concluded that the wing may be effectively used only in special conditions, hence this is not recommended for general application.

6

Simple methods for determination of the acoustical properties of ground surfaces

Gołębiewski R.

Archives of Acoustics

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2007

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Vol. 32, No. 4

827--837

EN

The interactions between the sound wave and the ground surface belong to the most important phenomena determining the outdoor noise propagation. In the present study, the exact theory of noise propagation and two simple models of the ground effect are analysed. The paper presents a method of determination of the effective flow resistivity, based on the twochannel measurement of the sound level (the exact theory). For the simplied model of the ground effect, the adjustable parameters are given as a function of the effective ow resistivity. Similarly for the ground effect model given by ISO 9613, the dependence of the ground factor (as a function of the effective flow resistivity) is presented. Additionally, for a few selected types of ground surfaces, the values of the model parameters were determined.