Sistem giroskop kawalan momen (CMG) adalah pilihan yang sesuai untuk bagi rekabentuk sistem kawalan atitud (ACS) satelit kecil bagi misi berprestasi tinggi kerana ia memiliki amplifikasi kilasan yang tinggi. Namun, kebolehan sistem ini adalah terhad dengan kehadiran unsur gangguan kerana limitasi pengawal atitud piawai untuk menolak gangguan tersebut secara teguh selain sistem CMG yang berdepan degan masalah sudut gimbal tersesar. Dalam kajian ini, kawalan daya aktif (AFC) dicadangkan dan diintegrasikan bersama pengawal berkadaran-terbitan bagi mengarah sistem CMG menjana kilasan kawalan bagi misi yang ditetapkan manakala sistem pampasan sudut gimbal kilasan magnetik (MTGAC) diintegrasikan ke dalam ACS untuk memampas gimbal tersesar sudut. Kesemua model matematik dibina dan dilaksanakan dalam perisian Matlab®-SimulinkTM. Berdasarkan simulasi, skema AFC yang dicadangkan sangat mempengaruhi prestasi manuver atitud dan tudingan atitud satelit. Dengan memilih parameter AFC yang sesuai, manuver atitud yang dikehendaki dapat dicapai dan ralat atitud dapat dikurangkan dengan ketara lebih dari 60%. Manakala, sistem MTGAC berjaya mengekalkan gimbal-gimbal GKM pada sudut yang dikehendaki lantas meletakkan sistem CMG jauh dari ketunggalan. Tambahan itu, sistem MTGAC juga memberi darjah kebebasan tambahan kepada kawalan tudingan atitud apabila ia menambahbaik ketepatan atitud sebanyak 75% tanpa mempengaruhi prestasi mavuver atitud satelite. Penemuan kajian ini telah pertama kalinya mendemonstrasikan keandalan skema AFC and MTGAC bagi satelit kecil dengan sistem CMG yang sebelum ini belum pernah dikaji.
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A control moment gyroscope (CMG) system is the best option for attitude control system (ACS) design of small satellite for high performance missions due to its high torque amplification. However, the capability of the CMG system with the present of disturbance elements is limited due to the limitation of standard attitude controller to robustly reject these elements whereas the CMG system faces gimbal angle offset problem. In this research, active force control (AFC) is proposed and integrated with the proportional-derivative (PD) controller to command the CMG system to generate suitable control torque for a defined mission whereas magnetic torque gimbal angle compensation (MTGAC) system is integrated into the ACS to compensate gimbal angle offset. All mathematical models were established and implemented in Matlab®-SimulinkTM software. Based on the simulations, the proposed AFC scheme greatly influenced the attitude manoeuvre and attitude pointing performance of the satellite. By selecting suitable AFC parameters, a desirable attitude manoeuvre was achieved and the attitude errors were significantly reduced by more than 60%. Meanwhile, the MTGAC system successfully maintained the CMG gimbals at preferable angle. Moreover, the MGAC system also added an extra degree of freedom to the attitude pointing control when it improved the attitude accuracy as much as 75% without affecting the attitude manoeuvre performance of the satellite. The research findings have been the first that demonstrate the viability of AFC and MTGAC scheme for ACS of small satellite with CMG system which has never been studied before.
An active force control (afc) based control momen gyros for attitude control of small satellite / Mohd Badrul Salleh