中島 晋太郎

The low reliability of nano-satellites has become a problem, with the cause often being defects in the design and manufacturing process. It is required to take sufficient measures to account for those defects through ground tests to reduce on-orbit failures. The model-based fault diagnosis method can prevent oversight of fault candidates and compensate for a lack of knowledge in human-based diagnosis. Since the developing time of nano-satellites is limited, fault diagnosis needs to be carried out efficiently also while being careful not to cause secondary faults. This paper presents a novel method that can find the appropriate command to verify candidates of fault location in a satellite. The proposed method can consider the side effect of a command and the efficiency of narrowing them down by using the information transmission path model. In the case study, the proposed method is applied to an earth-orbiting 6U CubeSat, and this case study reveals that 33% of the failures that occur in ground tests can apply to the proposed method. In addition, the proposed method can identify the fault location of some of these failures, although there are several limitations to implementing the proposed method in the actual satellite development.

短期間かつ高信頼度での開発が求められる超小型衛星では,ハードウェア,およびソフトウェアにおいて実績品を再利用することが有効である.しかし,衛星によって構造やミッションが異なることから,ソフトウェアは各機関が毎回個別に開発することが多い.そこで本研究では,姿勢制御系ソフトウェアのモジュールを衛星の構造に応じて自動生成するシステムの構築を行った.これにより,多様な超小型衛星において再利用性の高い姿勢制御系ソフトウェアを実現する.