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

Abstract

DESIGN AND DEVELOPMENT OF A TEST SETUP FOR REACTION WHEEL SYSTEMS OF NANOSATELLITES Abstract Nanosatellites 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 controller NANO UYDULARIN TEPKI TEKERI SISTEMLERI ICIN TEST DUZENEĞI TASARIMI VE GELISTIRILMESI Ozet Nano uydular gelisen teknoloji sayesinde uzay uygulamalarinda onemli bir yer edinmistir. Basarili bir operasyon icin uydularda yonelim belirlenmesi ve kontrol sistemleri hayati onem tasimaktadir. Tepki teker sistemleri nano uydular icin yaygin olarak kullanilan bir yonelim tahrik sistemidir. Elektrik motoru tahrikli bir tepki tekeri, momentumun korunumu ve etki-tepki yasasindan yararlanarak calisan bir sistemdir. Bu calismada, nano uydularda tepki teker  sistemleri icin bir test duzeneginin tasarimi ve gelistirilmesi verilmistir. Bu test duzenegi kullanilarak tepki tekerlerinin farkli konfigurasyonlari test edilebilmekte, farkli kontrol yontemlerinin performanslari degerlendirilebilmekte ve tum sistemin enerji verimliligi belirlenebilmektedir. Ek olarak, oryantasyon acilari, sistem akimi, voltaji ve gucu gibi olculen test verileri, gelistirilen kullanici arayuzu araciligiyla kaydedilebilmekte ve izlenebilmektedir. Test duzenegi, bir platform, tepki tekerleri ve bir kontrol unitesinden olusmaktadir. Tepki teker konfigurasyonlarinin degistirilmesine izin veren test duzeneginin mekanik tasarimi Solidworks yaziliminda gelistirilmistir. Matlab Simulink ortaminda fircasiz dc motor tahrikli tepki tekerleri icin modelleme ve kontrol calismalari yapilmistir. Elektronik kontrol unitesi tasarlanmis ve Raspberry Pi kontrolor olarak kullanilmistir. Test platformu 3d yazici kullanilarak uretilmis ve ardindan alt bilesenler (elektrik kontrol ekipmanlari) platforma monte edilmistir. Sistemin fonksiyonel ve performans testleri basariyla gerceklestirilmistir. Spesifik olarak secilen bir tepki teker konfigurasyonu ile uydunun tutum kontrolu icin PD kontrol performans sonuclari verilmistir. Bu sonuclar simulasyon sonuclariyla eslesmekte ve sistem tasarimini dogrulamaktadir. Anahtar Kelimeler : Tepki Tekeri, Uydu, Tutum Kontrol, Yonelim, PD Kontrolcu