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속도 오차 외란이 반작용 휠 제어에 미치는 영향에 관한 실험적 연구
김지철,이형준,유지훈,오화석,Kim, Jichul,Lee, Hyungjun,Yoo, Jihoon,Oh, Hwasuk 항공우주시스템공학회 2016 항공우주시스템공학회지 Vol.10 No.1
There are many possible disturbance sources on such a spacecraft, but reaction wheel assembly (RWA) which is generally used for spacecraft attitude control is anticipated to be the largest. These effects on degradation of performance of spacecraft such as attitude stability. In reaction wheel, disturbance caused by imbalance and speed error. It is hard to emulate speed error disturbance because it is not coincide with wheel frequency. This paper concentrates on emulating and analyzing the speed error disturbance. Firstly, classify the causes that lead to speed error disturbance which generate RPM fluctuation. Secondly, simulated with disturbance driver module and reaction wheel assembly which are developed by Spacecraft Control Lab. Experimental investigations have been carried out to test the disturbance emulator module as a disturbance generator for RWA. Measurements and test have been conducted on various fault. Frequency analysis of test data show that speed error disturbance effects on wheel settling wheel speed or fluctuation type.
김지철,윤진혁,이준용,오화석,Kim, Jichul,Yoon, Jinhyuk,Lee, Junyong,Oh, Hwasuk 항공우주시스템공학회 2016 항공우주시스템공학회지 Vol.10 No.1
Bearing friction and disturbance are the important parameters in control spacecraft using reaction wheel. In this paper, those parameters are estimated by preload and oil quantity. In order to determine the bearing preload's impact on performance, measure the disturbance and the bearing friction coefficient with increasing the preload to the allowed amount. And, find the relationship between oil quantity and bearing friction coefficient, measure it with increasing the oil amount in the bearing. With these results as a reference, find the appropriate amount of preload and oil quantity.
소형 위성용 반작용 휠 개발 및 궤도내 구동 결과 분석
김지철,최윤호,이상철,오화석,Kim, JiChul,Choi, YunHo,Lee, Sangchul,Oh, Hwa-suk 한국항공운항학회 2015 한국항공운항학회지 Vol.23 No.4
An on-board reaction wheel is payload of small satellite for space environment test. The reaction wheel is designed for considering physical, electrical, and environmental requirements. In this paper, we report design, manufacturing process and operation performance verification. Furthermore, the specifications of environmental test are performed under environmental conditions for guarantee of stability and reliability. The operation and environment test results are presented to meet the requirements at the reaction wheel flight model.
콘 형상 제동장치의 축방향 압축변형에 대한 실험적 연구
김지철(Jichul Kim),이학렬(Hak-Yeol Lee),김일수(Il-Soo Kim),심우전(Woo Jeon Shim) 한국트라이볼로지학회 2002 한국트라이볼로지학회 학술대회 Vol.35 No.-
Axial crushing behavior of cylindrical shell is utilized in the braking of the high-velocity impacting object. In this paper, truncated cone shape brake device is introduced. That is, thickness of the shell is increased gradually from the impacting end to the other end. A detailed experimental investigation the quasi-static axial crushing behavior of truncated cone type brake devices has been performed. Specimens of various shape were tested to check the influence of design parameters such as length, radius, mean thickness, and conical angle of cylinder. Influence of the material properties were also investigated by adopting aluminum, low carbon steel, and stainless steel as constructing materials. By analyzing deformation procedures of the specimens, it is seen that conical angle influence the deformation mode and the sequence of the wrinkles generation. Braking distance and mean braking force of each specimen were predicted based on the crushing load measured from the tests.