著者

勝部 駿 佐原 宏典

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.70, no.1, pp.1-6, 2022 (Released:2022-02-05)

参考文献数

5

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In spacecraft systems, it is important to quickly detect and deal with anomalies. However, the increasing complexity of spacecraft systems makes it difficult to avoid failures using previous anomaly detection methods. In recent years, anomaly detection methods based on machine learning have been studied. But it is difficult for a spacecraft to detect anomalies autonomously in orbit. In this study, we propose an anomaly detection method that defines and monitors a single variable representing the health status of a spacecraft system, instead of monitoring a huge amount of telemetry data. We have confirmed that the single variable can represent the health status of a spacecraft system and can be applied to the anomaly detection method.

著者

内藤 子生 高田 守正

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空學會誌 (ISSN:18835422)

巻号頁・発行日

vol.5, no.44, pp.1205-1224, 1938-12-05 (Released:2009-07-09)

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The stress analysis of the wing is now in general calculated by the idea of so called "elastic axis". But the idea is based on the assumption that the metal covered wing is so rigid to torsion that any torque offers to the wing no torsional deflection, and that the torque offers no stress to flangess. Therefore it may be easily supposed that the former idea may fail in the case of large torque. The present paper discribes a rational and rigorous method of stress analysis for wings which was developed and successfully applied by the authors in desigh of an aeroplane. The principle of the present method is based on the well known fact that the total deflection of a beam is the sum of the bending deflection and the shear deflection, considering the whole structure as statically indeterminate. Applying the principle of minimum strain energy, the authors calculated both the energy of bending and the energy of shear as shown in the eqn. (13) of illustrative problem. So the paper notes to the idea of "Shear Lag", and treats it analytically. Fig.3 is the illustrative problem. Flanges are considered to take fiber stress only. Webs, skins and ribs are considered to take shear stress only, recieving no fiber stress in X direction. Shear stresses in webs and skins between ribs are considered constant, changing only at ribs. Balance of the forces are expressed in six components, eqns (1)→(6). The idea of Fig.4 leads to eqs (7)→(10). They may be reduced to the relation (11). Statics gives no farther relation, q is indeterminate and must be solved by the principle of mininum strain energy. Total strain energy may be expresseed by (13), equation for q by (14), required solution for q by (15), and the other unknown by (11) & (15). Thus the inter-action of ribs and skins to both spars are easily calculated, which should be compared with the theory of Paul Kuhn, treating the rib action in the wing of wooden spar (N.A.C.A. Tech. Rep. No 508, 1935). Chapter 5 and 6 are the formula which were practically applied by the authors in the design of a seaplane. In the appendix (the last chapter), phisical meaning of expression (15) are developed. When L=∞ or G=∞, exp. (15) is reduced to the idea of "elastic axis, " in which the first term is for bending and the recond term is for torsion. When tv=tL=0, exp. (5) is reduced to the formnla for fabric covered wing. Thus it is concluded that the idea of "elastic axis" can be correctly applied only for the region far away from wing root and not for the region near the wing root, where the present method is varlid and beneficient.

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空學會誌 (ISSN:18835422)

巻号頁・発行日

vol.8, no.80, pp.1319-1326, 1941-12-05 (Released:2009-07-09)

著者

辛島 桂一 佐藤 清 森戸 俊樹

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.41, no.468, pp.35-43, 1993

被引用文献数

2 1

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This paper concerns with the results of an experimental study on dynamic load characteristics in parachute inflation at a subsonic speed. The unsteady drag of the parachutes in the process of inflation is measured in a wind tunnel at <i>M</i>=0.2, and the opening shock load is examined in detail with emphasis on the effects of porosity and size of the models. It is shown that the circular vents near the edge of the canopy are more effective than the slit vents to reduce the opening shock load without considerable decrease of drag in the steady-state. Detailed examination reveals that the model geometry as well as descending speeds has no serious influence on the coefficients of the opening shock load <i>C</i>_m and the opening time <i>C</i>_t, if both <i>C</i>_m and <i>C</i>_t are defined by use of the effective references calculated from the concept of an equivalent parachute, which has a circular plane canopy with the reduced area obtainable by subtracting porous area from the geometric one.

著者

戸田 信雄

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.69, no.11, pp.313-315, 2021-11-05 (Released:2021-11-05)

参考文献数

3

著者

松田 敬

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.32, no.370, pp.603-611, 1984-11-05 (Released:2009-05-25)

著者

武井 悠人 佐伯 孝尚

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.69, no.11, pp.316-322, 2021-11-05 (Released:2021-11-05)

参考文献数

4

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小惑星探査機はやぶさ2は,2018年6月27日にリュウグウへ到着し,小惑星近傍フェーズへと入った.リュウグウの特性を調べるため,約1年半に渡り多様な科学観測が遂行された.また,ローバー/ランダーの展開,二度のタッチダウンによる表面/地下サンプル採取,人工クレーター生成実験など,多くの降下運用に成功した.本稿では,はやぶさ2ミッションにおける小惑星近傍フェーズの概要を,事前準備と実績に分けて紹介する.はやぶさ2の多様で複雑な小惑星近傍運用を成功させるため,往路巡航フェーズ期間を活用して事前に詳細な運用計画を検討し,多くの訓練を実施した.到着後は,明らかになるリュウグウの素性や運用の成否,探査機特性の変化へと柔軟に対応しつつ成果の最大化を図った.本稿では,小惑星近傍フェーズにおける降下運用の全体像に加え,各期間のハイライトや重要な判断の流れを報告する.

著者

柿沼 朝雄 片山 範明

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.48, no.557, pp.388-395, 2000-06-05 (Released:2019-04-11)

参考文献数

11

著者

斎藤 成文

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.27, no.300, pp.19-27, 1979-01-05 (Released:2009-05-25)

著者

小松 龍世 杉山 佑

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.69, no.6, pp.212-215, 2021-06-05 (Released:2021-06-05)

参考文献数

1

著者

田原 弘一 弓削 政郎 白崎 篤司 マルチネスサンチェス マヌエル

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 = Journal of the Japan Society for Aeronautical and Space Sciences (ISSN:13446460)

巻号頁・発行日

vol.52, no.608, pp.408-415, 2004-09-05

被引用文献数

4 2

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Low-power Hall thruster flowfields were calculated using a simple one-dimensional model to understand plasma characteristics and ion acceleration processes and to predict thruster performance. The influences of magnetic field strength and acceleration channel length were mainly examined. The thruster model for calculation is the THT-IV low power thruster developed in Osaka University. Generally, ions were produced in an upstream region from the anode to some axial location of the acceleration channel, and then they were intensively accelerated in a region downstream just from the ionization region. With too short channel, ionization began downstream just from the anode, and then ion acceleration also occurred in the same region, resulting in poor ion flux and low thrust performance. In large channel length, the channel was long enough to produce a fully-ionized plasma, and efficient ion production and acceleration occurred. When the magnetic field strength increased in the channel, ionization occurred in a more upstream region, and ion acceleration began in the same region; that is, ionization and acceleration overlapped in the relatively long region. On the other hand, with a weak magnetic field ion production and acceleration, intensively and efficiently, occurred in their thin regions. Furthermore, we tried to include unclear anomalous electron diffusions by changing a Bohm diffusion coefficient at each high magnetic field strength in order to fit a calculated performance to the measured one. The calculated discharge current almost equaled the measured one, and the thrust characteristic also agreed well with the measured one.

著者

東野 和幸 杉岡 正敏 棚次 亘弘 湊亮 二郎 笹山 容資 磯田 浩志

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.60, no.3, pp.115-120, 2012 (Released:2012-10-23)

参考文献数

8

被引用文献数

1 1

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The pyrolysis of Methylcyclohexane (MCH) is investigated for the purpose of a regenerative cooling system of hypersonic propulsion by using Endothermic Fuel (EF). The experimental apparatus has heating tube made from INCONEL alloy where MCH would pass through and be decomposed. To confirm the effects of endothermic reaction on the heat absorption, heat fluxes are measured at 9 cross sections in this heating tube. For each section, temperatures are measured at the inner and the outer radii of heating tube and heat flux can be evaluated by these temperature differences. The experimental results show that the endothermic reaction of MCH can confine the temperature increment of MCH in the heating tube and increase the heat fluxes when its temperature was greater than 900K. The numerical simulation can also indicate that MCH pyrolysis have begun around the same temperature. The chemical heat capacity by MCH pyrolysis can increase its total heat capacity to 1.4 times. These facts indicate the usefulness of the endothermic fuels and the possibilities of the regenerative cooling by them.

著者

竹田 繁一 河野 敬

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.52, no.601, pp.22-29, 2004-02-05 (Released:2019-04-17)

参考文献数

3

著者

古茂田 真幸 川幡 長勝 塚野 雄吉 小野 孝次

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.31, no.349, pp.75-91, 1983-02-05 (Released:2009-05-25)

参考文献数

9

被引用文献数

1 2

著者

小野 伝

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.21, no.229, pp.83-88, 1973 (Released:2009-05-25)

参考文献数

10

著者

名取 通弘 岸本 直子

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.47, no.551, pp.277-282, 1999-12-05 (Released:2019-04-09)

参考文献数

15

著者

グラモール カートC.

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.38, no.442, pp.580-582, 1990

著者

越智 徳昌

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会論文集 (ISSN:13446460)

巻号頁・発行日

vol.51, no.598, pp.621-627, 2003 (Released:2003-11-28)

参考文献数

8

被引用文献数

1 2

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Precise normal acceleration control is essential for missile guidance. Missiles with both front and rear control surfaces have a higher ability to control normal acceleration than missiles with front or rear control surfaces only. From the viewpoint of control, however, the control problem becomes a two-input-one-output problem, where generally control input cannot be determined uniquely. This paper proposes controlling angle of attack as well as normal acceleration, which makes the problem a two-input-two-output one and determines the controls uniquely. Normal acceleration command is given by a guidance system, but angle of attack command must be generated in accordance to the acceleration command without affecting the normal acceleration control. This paper also proposes such a command generator for angle of attack. Computer simulation is conducted using a nonlinear missile model to investigate the effectiveness of the control system along with control systems designed using three other methods.

著者

新井 和吉 高橋 秀明 浦澤 俊介 長谷川 直

出版者

一般社団法人 日本航空宇宙学会

雑誌

航空宇宙技術 (ISSN:18840477)

巻号頁・発行日

vol.11, pp.117-122, 2012 (Released:2012-10-10)

参考文献数

23

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A space debris shield for use with spacecraft and satellites was designed. A space debris shield is required to have high defense performance and be lightweight. In this paper, the pressurized wall in the shield composition was made into a double wall structure, and we considered inserting a liquid layer into the shield between these walls. First, the numerical analysis conditions of aluminum alloys of shield composition materials were established from reverse analysis using the ballistic limit equation of a Whipple shield. Using the scaled-down liquid shield, the liquid layer thickness was investigated by comparing the numerical analysis and impact tests that used a two-stage light gas gun. Next, the ballistic limit curve of a real-size liquid shield was examined using the numerical analysis. From these results, it was found that the liquid layer in the debris shield substantially slowed the velocity of incoming debris fragments.

著者

西岡 喬

出版者

一般社団法人 日本航空宇宙学会

雑誌

日本航空宇宙学会誌 (ISSN:00214663)

巻号頁・発行日

vol.61, no.5, pp.197, 2013-05-05 (Released:2017-06-17)