Instytut Podstawowych Problemów Techniki

Streszczenie:

Maintenance of aircraft is a complex process and therefore, in order to optimize the process, integrated information systems are increasingly used. Rapid development and wide availability of mobile devices equipped with powerful processors and with a wide range of modern communication connections suggests their high usability for enterprise IT systems. In the Department of Avionics and Air Armament of the Military University of Technology (WAT) an ERP-class (Enterprise Resource Planning) system, intended to support aircraft maintenance [4] has been designed and developed. The main concept of the system is to store the aircraft related and maintenance information in a central repository, i.e. in databases hosted on a central database server. This solution ensures concurrent availability of the data to a large group of authorized users. The key components of the system include the database server and client applications, which ensure access to centralized information resources, according to assigned user rights. The project involves development of client applications using three technologies: web, desktop and mobile one. Developed client applications have successfully passed integration tests performed using sample maintenance data. Currently works on user authorization security and wireless data security are under way.

Słowa kluczowe:

maintenance system, mobile application, aircraft

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Blade Tip Timing (BTT) is a non-intrusive method to measure blade vibration in turbomachinery. Time of Arrival (TOA) is recorded when a blade is passing a stationary sensor. The measurement data, in form of undersampled (aliased) tip-deflection signal, are difficult to analyze with standard signal processing methods like digital filters or Fourier Transform. Several indirect methods are applied to process TOA sequences, such as reconstruction of aliased spectrum and Least-Squares Fitting to harmonic oscillator model. We used standard sine fitting algorithms provided by IEEE-STD-1057 to estimate blade vibration parameters. Blade-tip displacement was simulated in time domain using SDOF model, sampled by stationary sensors and then processed by the sinefit.m toolkit. We evaluated several configurations of different sensor placement, noise level and number of data. Results of the linear sine fitting, performed with the frequency known a priori, were compared with the non-linear ones. Some of non-linear iterations were not convergent. The algorithms and testing results are aimed to be used in analysis of asynchronous blade vibration.

Słowa kluczowe:

turbomachinery, blade vibration, tip-timing, sine fitting, least squares, harmonic oscillator

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Modelowanie dynamiki lotu statku powietrznego jest procesem, w wyniku którego można uzyskać odpowiedź na pytania: jak zachowuje się badany statek powietrzny oraz jak należy nim sterować, aby wykonał przewidziane zadanie. W ramach prac prowadzonych w Zakładzie Awioniki i Uzbrojenia Lotniczego Wojskowej Akademii Technicznej zbudowano dydaktyczny symulator kabiny współczesnego samolotu pasażerskiego z zaimplementowanym modelem ruchu statku powietrznego. Oprócz symulacji pracy przyrządów pokładowych stanowisko może służyć do analizy wpływu poszczególnych parametrów geometrycznych, masowych i innych charakterystyk statku powietrznego na jego zachowanie. Dzięki temu możliwe jest podczas zajęć dydaktycznych przebadanie wielu konfiguracji samolotu bez rozwiązywania trudnych zagadnień matematycznych. Studenci mogą więc więcej czasu poświęcić na rozpatrywanie różnych przypadków i analizę jakościową na podstawie przeprowadzonego wirtualnego lotu.

Słowa kluczowe:

dynamika lotu, statek powietrzny, symulator kabiny statku pasażerskiego

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Small drones with total mass of a few kilograms are becoming more and more popular in many applications increasing the probability of occurrence of emergency situations caused by an equipment failure or a human error. In case of a fall from a high altitude very often it is possible to use parachute rescue systems, which however require relatively long time for deployment and development of braking forces. The touchdown velocity may be large enough to exceed limit accelerations for UAV equipment. The paper presents the concept of deployable airbag systems, in particular with adaptive flow control, which provides a possible solution to the above-mentioned problems. The paper discusses the overall control and adaptation strategy. Simplified methods for mathematical modeling are proposed and formulated for an example on a cylindrical airbag. The conceptual part is concluded with the presentation of the methodology of experimental verification and results of initial tests of the integrated airbag system.

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Safe indoor flights of unmanned aerial vehicles (UAVs) requires an independent measurement systems, that will enable efficient navigation in the absence of GPS data. One of the many solutions currently being developed is the use of information about changes in the value of the local magnetic field. This paper presents ways of recording, visualizing and mapping local magnetic field changes that can be used as a support for indoor navigation systems. At the beginning we reviewed devices for acquisition of magnetic field strength and the type of data being recorded. In the next step we analyzed the possibilities of visualization of acquired data. Finally the methods used to generate magnetic field maps of enclosed areas have been presented. In each of the aspects covered in this paper, solutions developed by the authors will be described.

Słowa kluczowe:

Magnetic field, Position estimation, UAV, Indoor Navigation, Avionics.

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This paper presents in details design and development of a probe for measuring airflow data for an unmanned aerial vehicle (UAV). The research regards the definition of the requirements and dimensions of the device and limits the measurements to selected aerodynamic parameters only. In the design concept the five parameters gauged in the two independent sections of the probe were envisaged. In the first section temperature, stagnation and static pressure and in the second section flow angles - sideslip and angle of attack (AoA) were determined. The development has been divided into three stages. The first stage included a formulation of the guidelines for the construction of the mechanical elements. The specified requirements included the maximum size of the probe and the resultant restriction on the size of the sensors and their electronics hardware circuits. The next stage was focused on sensors selection and electronics hardware development. Additionally, an appropriate microcontroller system for sensors control and data acquisition was developed. The final stage included formulation of a software algorithm and its implementation. Eventually, the probe was installed on a mini UAV for inflight tests which verified the correctness of the design.

Słowa kluczowe:

Probes, Electron tubes, Temperature measurement, Aerodynamics, Sensors, Blades, Unmanned aerial vehicles

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This paper presents a conception of an indoor positioning system for an unmanned aerial vehicle (UAV). The measurement of magnetic field is a main source of information required to estimate a position of the platform. It is a parameter which can be measured with affordable sensors and is easy to obtain. In order to use acquired data, a magnetic field map of the specified environment should be previously determined. Thus, a few ideas of using this information were elaborated. First of all, dedicated hardware had to be designed to implement the method. In this process, a multipurpose measurement system was developed. The measurement system consists of three axis digital magnetometers and battery powered microprocessor system with SD memory card and LCD display. The module was installed on the specially designed chassis that enable testing on 3 different heights. The verification tests were performed in designated room, where permanent magnets were used to modify local magnetic field that could work as beacons.

Słowa kluczowe:

Magnetic field measurement, Magnetic fields, Magnetometers, Earth, Unmanned aerial vehicles, Sensors, Sea measurements

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Streszczenie:

The uncertainty of non-contact blade vibration measurements depends on the precision of time-of-arrival (TOA) or phase measurement. Various TOA estimation methods are used in the existing tip-timing measurement systems, which contribute to differences in vibration amplitude results. The known hardware triggering circuits have structure related to the sensor type and limitations specific to analogue circuits. The paper reviews the current hardware and software methods for conditioning of tip sensors and estimation of time of arrival, including customizable triggering circuits and processing of the sampled sensor output. It presents some measurement solutions developed at ITWL and example results. Selected algorithms of phase estimation, their possible implementation and performance issues are discussed. An exemplary software phase detector, implemented as a state machine, able to adapt to the mean pulse amplitude and ignore noise peaks is demonstrated. Numerical techniques, such as linear and polynomial interpolation and curve fitting, are proposed to process sampled sensor signal in order to increase resolution in time and measure characteristics of the blade-related pulse, including zero-crossing, maximum amplitude, rise time and pulse width. The selection of optimum clock or sampling rate in relation to the blade passing frequency and pulse rise time is discussed.

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