DESIGN AND DEVELOPMENT OF A TEST SETUP FOR REACTION WHEEL SYSTEMS OF NANOSATELLITES

DESIGN AND DEVELOPMENT OF A TEST SETUP FOR REACTION WHEEL SYSTEMS OF NANOSATELLITES AbstractNanosatellites have gained an important place in space applications thanks to developing technology. For a successful operation, attitude determination and control systems in satellites are vital. A reaction wheel system is the widely used drive system for nanosatellites. An electric motor driven reaction wheel is a system that operates utilizing from conservation of momentum and law of action and reaction. In this study, the design and development of a test setup for reaction wheel systems of nanosatellites are given. By using this test setup, different configurations of reaction wheels can be tested, performances of different control methods can be evaluated, and the energy efficiency of the whole system can be determined. Additionally, measured test data such as orientation angles and system current, voltage, and power can be recorded and monitored via the developed user interface. The test setup consists of a platform, reaction wheels, and a control unit. The mechanical design of the test setup which allows changing reaction wheel configurations is developed in Solidworks software. Modeling and control studies are performed in Matlab Simulink environment for brushless dc motor driven reaction wheels. The electronic control unit is designed, and Raspberry Pi is used as a controller. The test platform is produced by using 3d printer and then, subcomponents (electrical control equipment) are assembled into the platform. The functionality and performance tests of the system are performed successfully. The PD control performance results for attitude control of the satellite with the specific reaction wheel configuration are given. These results match the simulation results and validate the system design.Keywords: Reaction Wheel, Satellite, Attitude Control, Orientation, PD controllerNANO UYDULARIN TEPKİ TEKERİ SİSTEMLERİ İÇİN TEST DÜZENEĞİ TASARIMI VE GELİŞTİRİLMESİ ÖzetNano uydular gelişen teknoloji sayesinde uzay uygulamalarında önemli bir yer edinmiştir. Başarılı bir operasyon için uydularda yönelim belirlenmesi ve kontrol sistemleri hayati önem taşımaktadır. Tepki teker sistemleri nano uydular için yaygın olarak kullanılan bir yönelim tahrik sistemidir. Elektrik motoru tahrikli bir tepki tekeri, momentumun korunumu ve etki-tepki yasasından yararlanarak çalışan bir sistemdir. Bu çalışmada, nano uydularda tepki teker  sistemleri için bir test düzeneğinin tasarımı ve geliştirilmesi verilmiştir. Bu test düzeneği kullanılarak tepki tekerlerinin farklı konfigürasyonları test edilebilmekte, farklı kontrol yöntemlerinin performansları değerlendirilebilmekte ve tüm sistemin enerji verimliliği belirlenebilmektedir. Ek olarak, oryantasyon açıları, sistem akımı, voltajı ve gücü gibi ölçülen test verileri, geliştirilen kullanıcı arayüzü aracılığıyla kaydedilebilmekte ve izlenebilmektedir. Test düzeneği, bir platform, tepki tekerleri ve bir kontrol ünitesinden oluşmaktadır. Tepki teker konfigürasyonlarının değiştirilmesine izin veren test düzeneğinin mekanik tasarımı Solidworks yazılımında geliştirilmiştir. Matlab Simulink ortamında fırçasız dc motor tahrikli tepki tekerleri için modelleme ve kontrol çalışmaları yapılmıştır. Elektronik kontrol ünitesi tasarlanmış ve Raspberry Pi kontrolör olarak kullanılmıştır. Test platformu 3d yazıcı kullanılarak üretilmiş ve ardından alt bileşenler (elektrik kontrol ekipmanları) platforma monte edilmiştir. Sistemin fonksiyonel ve performans testleri başarıyla gerçekleştirilmiştir. Spesifik olarak seçilen bir tepki teker konfigürasyonu ile uydunun tutum kontrolü için PD kontrol performans sonuçları verilmiştir. Bu sonuçlar simülasyon sonuçlarıyla eşleşmekte ve sistem tasarımını doğrulamaktadır.Anahtar Kelimeler: Tepki Tekeri, Uydu, Tutum Kontrol, Yönelim, PD Kontrolc

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Since 1975, India has built 25 satellites under the satellite programme. By judicially combining the foreign technological imports and local knowledge, India appears to have acquired a high level of capability to build very complex and world-class satellites for remote sensing and communications. This paper analyses the process of technological learning in satellite building in India. Particularly, it illustrates the role of foreign imports and the local efforts at different phases during this process. This paper demonstrates that achieving the goal of technological self-reliance in a developing country like India, particularly in a complex area like satellite systems, is unlikely to be possible without significant foreign imports in the formative period. It also demonstrates that without strong indigenous effort India would not have reached threshold capability in the accumulative phase. Foreign imports and local knowledge appears to have played a complementary role in competence building in satellite technology in India

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Classical and intelligent methods in model extraction and stabilization of a dual-axis reaction wheel pendulum: A comparative study

Controlling underactuated open-loop unstable systems is challenging. In this study, first, both nonlinear and linear models of a dual-axis reaction wheel pendulum (DA-RWP) are extracted by employing Lagrangian equa-tions which are based on energy methods. Then to control the system and stabilize the pendulum's angle in the upright position, fuzzy logic based controllers for both x -y directions are developed. To show the efficiency of the designed intelligent controller, comparisons are made with its classical optimal control counterparts. In our simulations, as proof of the reliability and robustness of the fuzzy controller, two scenarios including noise -disturbance-free and noisy-disturbed situations are considered. The comparisons made between the classical and fuzzy-based controllers reveal the superiority of the proposed fuzzy logic controller, in terms of time response. The simulation results of our experiments in terms of both mathematical modeling and control can be deployed as a baseline for robotics and aerospace studies as developing walking humanoid robots and satellite attitude systems, respectively.The work of U.F.-G. was supported by the government of the Basque Country for the ELKARTEK21/10 KK-2021/00014 and ELKARTEK22/85 research programs, respectively