​14.5.2019 • Ve dnech 23. - 25. dubna se na půdě Military Technical Academy v Bukurešti konala studentská mezinárodní vědecká konference „CERC 2019". Té se pravidelně se účastní na dvě stovky rumunských, polských, maďarských, českých a dalších zahraničních studentů. Mezi nimi tradičně nechyběli ani studenti Univerzity obrany, konkrétně studenti magisterského studijního programu „Vojenské technologie" rotmistři Josef Blažek, Karel Glasl a Jan  Pecina spolu se  svobodníky Jakubem Horníčkem a Tomášem Dražanem. 

Jmenovaní studenti jsou během svého studia na univerzitě zapojeni do řešení vědecko-výzkumných úkolů FVT, konkrétně do projektu specifického výzkumu pod vedením podplukovníka Josefa Bajera z Katedry letecké techniky a také do studentské tvůrčí činnosti formou pomocných vědeckých sil pod vedením kapitána Zdeňka Josky a kapitána Zdeňka Pokorného z Katedry strojírenství.

Bukurešťská konference byla tematicky členěna do sekcí, přičemž studenti FVT byli na základě vypracovaných prací zařazení do panelů „9. Electrical Engineering and Electronic Systems", „11. Computer Science, Modelling and Simulation" a „6. Materials Technology". Se svým zařazením do jednotlivých panelů mohli být naši studenti spokojeni, o čemž svědčí získaná místa na stupních vítězů. 

Na závěr připojujeme krátké anotace soutěžních prací studentů UO v původním znění. Abstrakty všech soutěžních prací a plné texty všech oceněných budou koncem května 2019 zveřejněny na webových stránkách konference: http://www.mta.ro/international/en/cerc/

Ultra Wide Band Indoor Positioning System

This paper is aimed to designing, implementation and experimental verification of indoor positioning system. Actually it exists a lot of technical solutions, which can be used for determination of position of moving object indoor, such as WiFi, Bluetooth or Ultrasound. This project is based on Ultra Wide Band (UWB) technology, which provides a lot of advantages such as resistance to multipath propagation, low power consumption and very high accuracy. Concretely our system was based on integrated circuit DW1000 from Decawave company, which was invented especially for this purpose and with guaranteed accuracy of 10 cm. For distance measurement is used of TOA method, concretely the way called "Two-way-ranging". Distance measurement by this method is based on message transmissions between moving object and fixed stations and saving their timestamps. The first measurements were realised on development kit TREK1000. The first version was created PCB based on module DW1000, which was controlled by 8-bit microcontroller AtMega328p. This solution was fully compatible with commercial system TREK1000, but AtMega328 didn't dispose of enough speed for reliable DW1000 handling. Second version is based on on 32-bit microprocessor ARM-M3 STM32F107, which controls DW1000 module via SPI, measures distances and provide measured information via UART. After comparing of results, we can pronounce, that we achieved of high accuracy, so this system can be used for indoor navigation of unmanned aerial vehicles.

Ultrasonic Aircraft Airspeed Measurement

The purpose of this work is to verify a novel concept, which replaces conventional aircraft on-board aerometric instruments for measurement of airspeed, angle-of-attack and vertical airspeed by three pairs of ultrasonic transducers and identify advantages and disadvantages of this solution. The basic idea is to replace multiple flight instruments with only one device. The main question is: Can we perform measurement of airspeed, angle-of-attack and vertical airspeed with an appropriate precision using ultrasonic sensor? Another question is: For which conditions and range of airspeed is our measurement suitable? The circuit is implemented using three commercial specialized integrated circuits TDC1000, TDC7200 and ATmega328P. The first one as an ultrasonic analog front-end, the second one for time interval measurement. The last one is an 8-bit microcontroller and it is used for controlling the measurement and computing measured values. Proposed principle was verified by experimental measurements using 40kHz ultrasonic transducers.

Parallel Computing in Positioning Systems

The purpose of this work is to find suitable parallel algorithm to calculate position of a moving object using TDOA navigation method. Research is focused on GPGPU (General Purpose Graphical Processing Unit) processing and CPU (Central Processing Unit) multi-thread applications. The main requirement on these calculations is to find fast parallel algorithm with smallest possible inaccuracy in determined position. Codes are written in CUDA C++ programming language for calculations on GPGPU and in a C/C++ language for CPU programs. Hyperbolas in TDOA (Time Difference Of Arrival) system are represented by x, y coordinates vectors. Research also compares computing capabilities of each architecture. For computing are used GTX 1060 and GTX 1070 Nvidia graphic cards and Intel core I7 8700 and AMD Ryzen 5 1600 processors. Result of the research led to implementation and verification of effective parallel algorithms for both, GPGPU as well as CPU processing units.

Duplex Coating on Stainless Steel

Austenitic stainless steel is widely spread in industrial applications due to corrosion resistance,good weldability and formability. Nevertheless due to low hardness and strength there is limited its applying. A combination of plasma nitriding and PVD coating such surface treatment has been used to improve material properties like hardness and scratch resistance without influence the corrosion performance. A duplex treatment was investigated in presented work. In this work the duplex treatment consists of a plasma nitriding at 783K for 30 hours and subsequent PVD coating ZrN coatingwere applied on AISI 316L steel. The article is concerned to study mechanical properties of duplex system using indentation methods. Measurement was done on the universal instrumental hardness tester Zwick ZHU 2,5. Hardness was measured at load in range between 2N and 100 N. Microhardness was measured on automatic hardness tester LECO AMH 55. From measured values, thickness and microhardness of nitrided layer was experimentally determined. Adhesion of coating was measured by Rockwell indentation test. Coefficient of friction was measured by scratch test on Bruker UMT Tribolab device. Load increased from 0 up to 30 N. The results of scratch test were compared with results of measuring on a confocal microscope Olympus OLS 3000.The results of measurement of friction coefficient show big differences between coated and duplex treated specimen. Coefficient in case of duplex treated specimen remain almost the same - 0,05. However for nitrided specimen friction coefficient increased from 0,05up to 0,25.The duplex treatment of the steel surface has a very good effect on the tribological properties of the surface, thus increasing the application potential of these steels to new areas.

Surface Treatment of Construction Steels Used in Military Technology

The work deals with the analysis of mechanical properties of structural steel surfaces modified by using diffusion technologies of plasma and gas nitriding. Nitriding was applied to structural steels ČSN 41 2050, ČSN 41 5142 and ČSN 41 6341, which are widely used in various machine parts of the Czech Army weapon systems. These steels were refined prior to the application of nitriding technologies to refine the grain, thus the microstructure formed in the steels improves not only the nitrogen diffusion process into the base materials but also improves the core properties. Samples were prepared from selected steels, after which their chemical composition of basic material, microstructure and mechanical properties of nitrided layers were evaluated. The chemical composition of steels was evaluated by the GDOES / Bulk method on LECO SA 2000, the mechanical properties of nitrided surfaces were evaluated by measuring the universal hardness on the universal hardness tester ZWICK ZHU 2.5. The thickness of the formed nitrided layers was evaluated by the microhardness measurement on the LECO AMH 55 automatic micro hardness tester. The results showed that the surface hardness of all tested materials increased significantly. Steel steels ČSN 41 5142 and ČSN 41 6341 achieved higher surface hardness by plasma nitriding. When measuring the thickness of nitrided layers in all cases, plasma nitriding achieved a higher nitrided layer thickness than in nitride gas samples. The results of this work have shown that modification of structural steel surfaces by plasma and gas nitriding methods offers great application potential for use in various weapon systems.

Autor: Michal Dub

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