Kendinden Hareketli Denizaltı Modeli Tasarımı ve Prototip İmalatı

Abstract

Denizaltılar için hayati öneme sahip olan manevra kabiliyeti, günümüzde analizler sonucunda tahmin edilebilmektedir. Deneysel yöntemlerle belirlenecek manevra türevleri ise, manevra kabiliyeti hakkında öngörülemeyen durumları sağlayacaktır. Bu kapsamda tasarımı ve prototip imalatı yapılan model denizaltı, deneysel çalışmaların yapılabilmesi için bir platform, deney sistemlerinin gelişebilmesi için ise ilk adım olacaktır. Herhangi bir takıntısı olmadan, kablosuz haberleşip, bağımsız güç kaynağı ile sevk edilen model, istenilen manevra deneylerinin havuzda ve denizde yapılmasına imkan sağlayacaktır. Akademik ve ticari kurumların denizaltı manevra kabiliyeti ve yeni denizaltı formları ile ilgili yaptıkları çalışmalar öncesi, yöntemlerini doğrulamak amacıyla uyguladıkları açık kaynak denizaltı formu olan DARPA Suboff modeli çalışmamızda tercih edilmiştir. Analiz ve hesaplamalar sonucu elde edilen denizaltı manevra türevleri, model deneyi yapılarak elde edilen manevra türevleri ile karşılaştırılacak, model verileri ile örtüşmesi halinde, analiz ve hesaplama yöntemleri ile bir başka denizaltının model deneyleri yapılmadan geometrisine dair manevra türevleri elde edilebilecektir. DARPA Suboff boyutsuz denizaltı modelinin 250 mm çap ölçüsü altında boyutlandırılması yapılmıştır. Round of revolution olan geometri, 7 kanatlı INSEAN 1619 pervanesi ile sevk edilmesi kararlaştırılmıştır. Maksimum hızı 2.5 m/s olacak şekilde model deneyleri için geçiş hızları belirlenmiştir. Denizaltı hacmi 3B çizimden hesaplanmış, tasarım esnasında öngörülen ağırlık ile su içerisinde askıda kalması için gerekecek ağırlık ilişkisi kurulmuştur. Baş, gövde ve kıç kısımlarında farklı malzemeler kullanılarak imalat gerçekleştirilmiş, imalat esnasında karşılaşılan sorunlar nedeniyle malzemelerde değişikliklere gidilmiştir. Sevk için gerekli güç hesaplanmıştır. Sevk sistemi öncelikle boyut ve sonrasında tork isterleri sebebiyle revize edilmiştir. Dümen sistemi de yapılan analizler sonucu değişmiş, iki motor ve iki dümenli yapıdan, dört motor iki dümen konfigürasyonuna dönülmüştür. Bir birleriyle ters yönlerde dönen, fakat senkron dümen hareketlerinde bulunması gereken motorlar için fonksiyon blokları oluşturulmuştur. Haberleşme için geliştirilen bloklar, toplanan akım, gerilim, pozisyon ve hız bilgilerinin kara bilgisayarına aktarılmasını sağlar. Kara bilgisayarından da modelin sualtı manevra bilgileri benzer haberleşme kod blokları ile kara bilgisayarından modele aktarılmaktadır. Model ve kara bilgisayarı arasında haberleşmenin akustik modem ile gerçekleştirilmesi hedeflenmektedir. Bunun yanında yazılım geliştirme ve test aşamalarında zigbee modülleri kablosuz haberleşmede kullanılmıştır. Ataletsel Seyrü Sefer sistemi olarak, Xsens firmasının MTI-G 700 sensörü kullanılmıştır. Altı eksende açı ve ivme değeri sağlayan sensör, üç eksende de magnatometre verisi vermektedir. Kalman filitresi uygulanmış açısal ivme ve pozisyon verileri model üzerindeki kontrol kartında işlenip, pozisyon ve hız verisi olarak her 100ms’de bir kara bilgisayarına aktarılmaktadır. İmalatı yapılan modelin sızdırmazlık testleri yapılmıştır. Tasarımda görülen mekanik eksiklikler değerlendirilmiş, yeni tasarım önerileri sunulmuştur. Bu öneriler detay tasarım olarak tamamlnmış, son olarak sorunlar, çözüm yöntemleriyle sunulmuştur. Elektronik kontrolü sağlanan modelin, mekanik tasarımı gelişme göstermekle birlikte havuz testlerinde zorluklar yaşanmasına sebebiyet vermiştir. Prototip imalatı yapılmış modelin revize edilerek tekrar imaline karar verilmiş, tekrar yapılan mekanik tasarım süresince bu tez kapsamında elde edilen tecrübelerden faydalanılmıştır.

Maneuverability is vital for submarines, that can be estimated in the current calculation methods. The maneuver derivatives will be determined by the experimental method will provide for unforeseen circumstances in maneuverability. In this context, the design and production of a model submarine,which will be a platform to perform the experimental tasks, is studied. It will also be the first step for the development of test systems that has not any obsession resistance. Independent power supply models communicate wirelessly without any obsession. Academic and commercial institutions must verify new forms and and calculations before their work related to submarine maneuverability.To verify the form of DARPA Suboff model, the calculation method is verified with model experiment. Analysis and results of calculation obtained submarine maneuvers derivatives is compared to maneuver derivatives obtained by model tests. If the overlap of the calculation result is excepted, the calculation method will be verified. Without any model experiments a submarine maneuvers derivatives may be obtained and analyzed on the geometry calculation methods. DARPA Suboff nondimensional model of the submarine is made by sizing diameter of 250 mm. The round of revolution geometry, it was decided to be propelled with the 1619 INSEE seven blades propeller. The maximum speed of 2.5 mt/s, so that the transition rate is determined for the model experiments. Submarine volume was calculated from the 3D drawing. Design was established with the prescribed weight during weight relationships need to remain suspended in water. Head, body, and back, were carried out using different materials . Changes were made in material due to the problems that encountered during manufacturing. Required power is calculated for propulsion system. Due to the size and torque prompts, propulsion system has been revised. The analysis results have changed the steering system. Two engine-two steering structure has been replaced with four engines and two steering structures. Rotating the rudders in a synchrous mode, each rudder on a plane must be turned opposite directions with the other ruuder on the same plane.In two planes, four rudders are grouped in pairs. For this purpose, new function blocks are coded for steering. A communication block is developed to transmit and receive data. The transmitted data includes, current, voltage, position and speed information. The position, velocity and tourqe commands are received from the land computer to model submarine. The information is received by a code block and there is a checksum control. The communication between the model and land computer will be carried out with an acoustic modem. However, zigbee modules are used to test the communication and codes. The embedded code and the user interface program are developped with this modules. These are communicates via RS 232 protocol. This feature allows to change the modules with other modules that able to communicate via RS 232 protocol. After receiving the MICRON DATA Modems which are acoustic modems, the modules will be changed. The communication range will be expend from 10 feets to 300 feets. As an inertial navigation system, MTI-G 700 which is a XSENS product is used. The sensor provides six-axis acceleration and angle data. In addition, it also gives three-axis magnetometer data. Angular momentum and position data are processed by applying the Kalman filter on control board. Calculated position and speed data is transferred to a land computer in every 100 ms. During this time period all the calculations run on the control board with 1ms sampling time. The submarine model which is manufactured is tested about sealing. Mechanical defects were detected. As a result of the experiments, the mechanical design is changed. The propulsion system is designed to assemble easily from inside of the back part. For the leak proofing of the propulsion system, a special felt is used. It is possible to use two felts to get better leak proofing profile. The rudder assembly design are changed three times. In the last design the rudder shaft bearings are assembled from outside of the back part. There are two screw threads on the back side on each bearing. Firstly, the bearings are assembled, then the shafts are positioned from inside towards outside. Firstly, the propulsion system is assemblied. After the shafts that posioned, the stteenless steel case is assemblied. The steenless steel case carries four rudder motors. After all mechanical connections that on the back part, cable connections is completed to a junction board. The junction board has two main cable cables towards the body of the submarine model. Two cables have one male and one female connectors. Moreover, there are two cables in the body part that lies towards back side, have connectors that mate with the back side connectors. This connection method is preffered to prevent any connection disasters. During the development of the model, body material is considered. Plexiglass material is used as the body. However, the material is not useful for this kind of sizes. In the next design, stainless steel will be preferred as a body material. According to body material the flanşes were not worked as designed. The mate planes were choosed wrongly. There were leakege between the plexiglass and flanşes from the mating faces. For this problem, a solution is found. The oring channels will be placed to mating faces and screws will be put pressure on this orings. So that, the pressure will extend the orings against the water. Head, body, and rear part’s assembly methods are changed. The mounting of the rear section is developed from the first design.On the other hand the mouting between head and the body is completly changed. The mechanical structure that needs to be placed in the body will be placed in to body from the head side with a slider mechanism. So that, this allows too much convenince to a person, who is doing research activity. Batteries, sensors, and the control board will be more accesible. The electrical connection between the rear part and slider system will be provided by connectors that fixed on slider side and the rear side. When the slider is going towards the rear, the connectors will mates and the connection will be completed. In conclusion, the model that designed is manufactured and tested. Many electrical and mechanical problems were faced. All of them are tried to be solved with the first prototype. All the electrical problems are nearly solved. The mechanical problems are tried to solve with the facilities. Leakege proofing tests gave to much experience about mounting methods. This allows to consider about the different materials that used as head, body and rear. The compatibility between the parts must be the first priority. According to this, the mounting and sealing methods are getting position in design.