平成18年10月(2006.10)

<p>ASTRO-H (hitomi) was an X-ray astronomy satellite in Japan which was launched on 17 Feb. 2016. To meet its science goals, four kinds of instruments and six detectors were equipped on the satellite. The focal length of two soft X-ray telescopes was 5.6 m, and that of two hard X-ray telescopes is 12m. One of the most difficult challenges for the satellite structure was to meet the alignment requirements for instruments and detectors. Through the ground tests and observation results on orbit, it was confirmed that the performance of alignment meet the requirements. In this paper, the results of on-orbit alignment performance of the instruments and obtained techniques to control the alignment are reported.</p>

To meet advanced science missions, large and precise support structures such as truss structures are needed. In this paper, pointing control of a truss structure is discussed. To control the truss structure, thermal expansion of truss members is utilized instead of mechanical actuators. Heaters are equipped to truss members so that the thermal expansion of the members is controlled by heaters. PI control is applied to an experimental model which is box truss with 1.9m height. Through experiments, it is shown that the truss structure can be controlled with good accuracy, for example, within ...

In SCOPE mission, flexible extendable rod antennas are equipped along the spin axis of satellite. For the extendable function, STEM (Stowable Tubular Extendable Member) is used as the rod antenna. The apparent natural frequency of the STEM changes depending on the spin-rate. Furthermore, bending and torsion of the STEM are coupled because the STEM has open section. The dynamic characteristics of the STEM are clarified through analysis and tests. Especially, the coupled vibration of bending and torsion, and the effect of spin motion on apparent natural frequency of the STEM are investigated. As a result, it was shown that the effect of spin motion can be quantitatively predicted by simple analytical model. In addition, it was found that the characteristics of the vibration are strongly affected by the boundary condition of the STEM.

Requirement for shape stability of space structures such as barrel for space telescope tends to become more precisely. In addition to it, large size over 10 meters is sometimes required for such support structure to meet advanced science missions. To realize large and precise support structures, comprehensive techniques including prediction, measurement and stabilization techniques on orbit are needed. In this paper, we introduce some fundamental techniques to keep the precise shape for a slender box truss as a representative support structure. The structural deformation on orbit is induced by thermal distribution, disturbance (RW/MW/SAD etc.) and so on. At first, we analyzed temperature distribution and thermal distortion of the truss structure to predict the thermal deformation. The accuracy of analysis results is evaluated through experiments with a five-bay truss structure. Then, system identification is carried out to identify the stiffness of the structure because such identification of the stiffness becomes important for the precise prediction of thermal deformation in the case of indeterminate structure. As a first step, the stiffness matrix is identified by using particle swarm optimization method from the experimental data of natural frequency. By using the identified stiffness matrix, the natural frequency can be estimated within 1% error. At last, we attempt the shape control of truss structure by using artificial thermal expansion. It is experimentally shown that deformation of truss structure could be controlled with good accuracy, for example, within 30μm error for 1.9m height truss. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

軽量かつ高収納効率を有する宇宙構造システムとして,内圧維持型のマルチセルインフレータブル構造の研究を行った.まず,マルチセルインフレータブルサンドイッチパネルを開発し,高い曲げ剛性を有することを解析と要素試験によって示した.さらに,パネルの大型化を試み,多段化による厚みの増大や,メートルオーダのパネルの開発を行った.また,マルチセルインフレータブルパネルの安定な展開法を示すとともに,内圧の変化を利用した形状制御機構を提案し,その有効性ついて,解析及び実験を通じて検証した.

平成19年度は,構造・環境・制御の相互作用によって形成される宇宙構造システムの研究として以下の3つの課題に取り組み,成果を得た.
課題1.環境力(重力傾斜)による構造形状の維持とその安定性解析
昨年度の結果をもとにして,重力傾斜を宇宙機システムの姿勢維持のみならず構造形状の維持に利用した新しい柔軟多体宇宙機システムを検討した.具体的には,非常に柔軟なパネル構造を複数バス系からテザーで支持する地球指向の太陽発電システムを対象とし,システムの安定性を重力,遠心力,歪みエネルギーからなるポテンシャルエネルギーを用いて評価した.さらに,安定な平衡点まわりにおける固有振動数,モード形状の導出を行うと同時に,重力傾斜を構造形状の維持に利用したシステムの特性を明らかにした.
課題2.環境力(圧力差)を利用した柔軟膜面構造とその動的特性評価
インフレータブル構造物を,構造内と環境との圧力差を利用した構造様式と捉え,内圧維持型のマルチセルインフレータブル構造の提案を行うと同時に,面内剛性の評価を実施した.さらに,展開時の動特性評価を行い,ケーブル要素による制御機構を組み込むことで,安定な展開が行えることを示した.
課題3.柔軟構造要素によって結合された小型衛星群のフォーメーションフライト
本年度は小型衛星群制御の要素技術として必至な,小型衛星の姿勢制御・決定系について,昨年開発・打ち上げに成功した超小型衛星HIT-SATのフライトデータを元に,その性能評価を行った.さらに,シミュレーションベースで,特定平面内をフォーメーションフライトする小型衛星群を柔軟構造要素で結合することにより,必要なスラスタ燃料が大幅に軽減されることを示した.

昨年度は,大規模宇宙構造システムを対象に,構造物の特性と姿勢変動の関係を明らかにした.その結果を基として,本年度は,さらに,軌道・姿勢・構造の3要素の干渉による非線形なシステムの動特性評価を推し進めると同時に,熱応力の影響や,構造変形(振動)や姿勢変動のそれぞれのモード間のエネルギーの伝搬と,モジュール間におけるエネルギーの伝搬についての研究を行った.その知見を元に,分散的に熱応力を解放可能なモジュール構造の提案を行った.その有効性は,シミュレーションにより検証された.具体的には以下の2点に関する知見を得た.(1)連成挙動の支配要因となる構造特性構造システムの柔軟性や形状といった構造特性が,軌道・姿勢・構造の3要素の連成に与える影響についての解析を行った.1次元的な重力傾度安定型宇宙構造物について,解析的にその支配パラメータを特定した.A.軌道運動と構造振動の固有振動数比,B.質量比,C.軌道半径に対する構造物の代表長の比の3点である.これらのうち,A.の要因が最も影響が大きく,その値が約10を越えた場合には,構造振動は,軌道・姿勢運動と独立と捉えて良いことが判明した.(2)エネルギーの伝搬を考慮した熱応力の分散解放構造熱応力存在下のテザー支持による大型宇宙構造物の構造変形及び姿勢変動の解析を行った.熱変形によって,テザーがスラックすると,その固有振動数が著しく低下し,構造振...

将来の宇宙構造物システムには、機能の多様性や、拡張性、さらには耐故障性に優れていることが望まれる。モジュール型の膜面展開構造物はそれらに対応できる構造物システムとして、今までにない新しい構造物の概念を提示しうる可能性を持っている。そのような構造物の研究のためには、モジュール構造の概念を明らかにすることと、ケーブルや膜面構造の力学特性を解明することが重要である。それら両者は現在の構造工学においては、いまだに十分なアプローチが確立していない困難な課題である。本研究では、モジュール構造の概念を考察して構造物システムのありかたを再検討し、また膜面に本質的なリンクル(しわ)現象の物理的な解釈にもとづいた新たな解析方法を提示するとともに、膜面のリンクル現象そのものも具体的に解明した。
モジュール構造の概念は人工物や自然物によく見られるが、人工物では製造、試験、輸送、解析などの観点から機能別にまとめられたサブシステムとして考えられてきた。それに対し自然物では同じ機能を持つ合同あるいは相似なモジュールが集まってシステムの全体を構成している。同じモジュールの繰り返しを階層的に人工物に取り入れることによって、従来の構造物が目指した方向とは別の可能性があることを、平面トラス構造を例として示した。
膜面要素のリンクル現象については、応力状態のみに注目した張力場理論にもとづいた解析と厳密な非線形有限要素解析とを並行して、二つの解析方法のそれぞれの利点を明らかにするとともに、具体的な膜面の挙動を明らかにした。さらに矩形膜の模型実験とを行った。それらの結果、膜面が強いリンクル状態にあっても安定した解析が可能となる修正応力歪みテンソルによる張力場有限要素法を提示し、またリンクル現象には境界周辺の影響が非常に強く現れることなどリンクル現象そのものの特性を明確にした。

本研究課題では、高齢者、身障者がパーソナルユースに使用する運動補助装置を対象に、操作や歩行動作におけるスキルダイナミクス、とりわけそこに内在するバイオ・カオスを評価し、これらの知見に基づいて人をフレンドリーにサポートする適応型インターフェースの構築を図ることを目標として、以下の成果を得た。
1.ヒューマンスキルに内在するバイオ・カオスのダイナミクスの解明と応用
身体動作のスキルの計測、特に二足歩行動作、発話動作を対象に、実データのカオス解析技法を発展させ、生体カオス特有の非線形性、非ホロノミック性を考慮した解析及び制御手法の開発を行った。
2.インテリジェントな情報処理、視覚ニューラルシステムの構成と応用
ニューラルネットワークなどのインテリジェントな情報処理において、視覚による知覚課題:動物体判別、顔認識、注意、中心視などのパルスニューロ・システムシミュレーションを行い、人工的な知覚認識のシステム構成の開発を行った。
3.マンマシン・インタラクションを考慮した適応型インターフェースの構成
電動車椅子を対象に人の搭乗時のダイナミクスを解析し、自在な経路計画,運動学制御により障害物を回避し,滑らかな速度履歴で移動するモデルシステムの構築を行った.さらに搭乗者と車椅子の相互作用による挙動特性を計測できる計測評価用電動車椅子を開発した。電動車椅子の操作時に生じる意図に反する現象、例えば蛇行、ハンチング振動などの現象に対する防止策の検討を行って、搭乗操作者の意図に反応するインターフェースの実現可能性を確かめた。

大気球シンポジウム 2020年度（2020年11月5-6日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 12名資料番号: SA6000151024レポート番号: isas20-sbs-024

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000146008レポート番号: A-7

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000146021レポート番号: B-01

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000146025レポート番号: B-05

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000146028レポート番号: B-08

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 14名資料番号: SA6000146022レポート番号: B-02

大気球シンポジウム 2019年度（2019年11月7-8日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000140016レポート番号: isas19-sbs-016

大気球シンポジウム 2019年度（2019年11月7-8日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 21名資料番号: SA6000140030レポート番号: isas19-sbs-030

<p>ゼロ熱膨張設計を行った炭素繊維強化複合材料（CFRP）製ハニカムサンドイッチパネルを主構造とした新しいアルミニウム反射鏡面を持つ軽量高精度鏡を部分的に製作し，「きぼう」簡易曝露実験装置（ExHAM）を用いて長期間宇宙空間に曝露させた後に地上に回収して詳細分析することで，地上試験では模擬できない，熱，紫外線，放射線，原子状酸素など複合的なストレス環境下での鏡面，材料，リフレクタ構造の耐性確認と長期間の経年劣化を定量的に得るためのCAGOME実験を開始したので紹介する．獲得された軽量高精度CFRP鏡の材料技術は高性能放射計（AMSR）等で計画される100GHz以上（テラヘルツ帯への拡張）のラジオメータに活用される．</p>

<p>天文衛星や地球観測衛星ではより大型で高精度な構造物が必要とされている．このような構造を構築するためには，軽量で弾性率が大きく熱膨張係数が小さい材料が必要である．熱膨張係数の小さい材料としては炭素や石英があり，各種の人工衛星の高精度構造にはこれらを利用した構造要素とその複合材料が活用されている．本稿では，電波天文衛星ASTRO-G（2011年中止）向け大型展開アンテナにおける各種高精度構造要素の構成素材に関する開発において発生した技術課題を発端として，筆者らが取り組んでいる将来のASTRO-Gのような大型アンテナをはじめとする高精度構造への適用を目指した材料および構造要素の開発に関する基礎的研究について紹介する．</p>

<p>For future advanced missions, large and highly accurate space structures are required. A prior shape adjustment of the structure before launch is not sufficient to achieve such accurate space structures. For example, thermal deformation on orbit cannot be eliminated by the preliminary adjustment of the structure. Therefore, the shape control of the structure is a promising technique for highly accurate space structures. For the shape control, the shape error should be measured on-orbit. In this study, a measurement system for the displacement of a slender space structure has been developed as an alignment monitor. The characteristics of this measurement system are long working distance and simple configuration. The measurement system consists of a laser, retro-reflector and positioning sensing device. The performance on the ground was already demonstrated through the satellite ground test. As a first step to on-orbit experiment, the demonstration experiment on the balloon is planned. In this paper, the system configuration and development progress are reported.</p>

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137027レポート番号: B05

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137039レポート番号: B17

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137041レポート番号: B19

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137042レポート番号: B20

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 15名資料番号: SA6000137008レポート番号: A08

大気球シンポジウム 平成30年度（2018年11月1-2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 27名資料番号: SA6000128002レポート番号: isas18-sbs-002

大気球シンポジウム 平成30年度（2018年11月1-2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 12名資料番号: SA6000128027レポート番号: isas18-sbs-027

大気球シンポジウム 平成30年度（2018年11月1-2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県資料番号: SA6000128029レポート番号: isas18-sbs-029

© 2018 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. This paper develops an athermalization method to cancel the mismatch of the coefficient of thermal expansion (CTE) that exists in active control mechanisms, through analysis, prototyping, and tests. Essentially, the CTE mismatch between piezoceramics and the other structures made of super invar is cancelled by combing with another metallic part. In addition, this paper clarifies the mechanism of thermal deformation caused by inner structure of a piezoelectric stack actuator. It shows in both finite-element analysis and tests that the CTE mismatch cancellation is affected by the dimension tolerance of the inner structure, but successfully adjustable by the proposed methods. Moreover, the high thermal sensitivity of the actuator is exploited to propose another type of smart actuator, which uses active thermal deformation. This alternative approach is also evaluated through analysis, prototyping, and tests.

The ASTRO-H mission was designed and developed through an international collaboration of JAXA, NASA, ESA, and the CSA. It was successfully launched on February 17, 2016, and then named Hitomi. During the in-orbit verification phase, the on-board observational instruments functioned as expected. The intricate coolant and refrigeration systems for soft X-ray spectrometer (SXS, a quantum micro-calorimeter) and soft X-ray imager (SXI, an X-ray CCD) also functioned as expected. However, on March 26, 2016, operations were prematurely terminated by a series of abnormal events and mishaps triggered by the attitude control system. These errors led to a fatal event: the loss of the solar panels on the Hitomi mission. The X-ray Astronomy Recovery Mission (or, XARM) is proposed to regain the key scientific advances anticipated by the international collaboration behind Hitomi. XARM will recover this science in the shortest time possible by focusing on one of the main science goals of Hitomi, "Resolving astrophysical problems by precise high-resolution X-ray spectroscopy".(1) This decision was reached after evaluating the performance of the instruments aboard Hitomi and the mission's initial scientific results, and considering the landscape of planned international X-ray astrophysics missions in 2020's and 2030's.Hitomi opened the door to high-resolution spectroscopy in the X-ray universe. It revealed a number of discrepancies between new observational results and prior theoretical predictions. Yet, the resolution pioneered by Hitomi is also the key to answering these and other fundamental questions. The high spectral resolution realized by XARM will not offer mere refinements; rather, it will enable qualitative leaps in astrophysics and plasma physics. XARM has therefore been given a broad scientific charge: "Revealing material circulation and energy transfer in cosmic plasmas and elucidating evolution of cosmic structures and objects". To fulfill this charge, four categories of science objectives that were defined for Hitomi will also be pursued by XARM; these include (1) Structure formation of the Universe and evolution of clusters of galaxies; (2) Circulation history of baryonic matters in the Universe; (3) Transport and circulation of energy in the Universe; (4) New science with unprecedented high resolution X-ray spectroscopy. In order to achieve these scientific objectives, XARM will carry a 6 x 6 pixelized X-ray micro-calorimeter on the focal plane of an X-ray mirror assembly, and an aligned X-ray CCD camera covering the same energy band and a wider field of view. This paper introduces the science objectives, mission concept, and observing plan of XARM.

<p>In this paper, large space structures such as solar power satellite systems are investigated from the view point of construction. For large space structures, it is necessary to satisfy different requirements depending on the phases. During launch, the strength against the launch load and small storage size are required to the structure. Although the load conditions are greatly relaxed after launch, maintenance of large area is required on orbit. In order to satisfy the different requirements for each phase, deployment mechanisms and assembly techniques in space have been studied. In this paper, functional requirements for the construction of large space structures are investigated. After the hardware designs of an assembly mechanism, its fundamental characteristics are shown.</p>

&lt;p&gt;人工衛星を用いたミッションの高度化に伴い，衛星搭載用のアンテナや望遠鏡といった衛星搭載機器も，より高精度であることが求められている．そのような高精度な機器の実現に向け，軌道上での変形を計測し，アクチュエータにより補正することで高い精度を得る形状可変構造システムが，多くの機関で研究・開発されている．著者らも積層型圧電素子と変位拡大機構を組み合わせたアクチュエータを用いてアンテナ反射鏡面の形状調整を行う形状可変鏡（スマート形状可変鏡）の研究・開発に取り組んでおり，製作したアクチュエータの性能評価や，実際のアンテナシステムに組み込んだ状態での形状可変鏡の有効性確認試験を実施している．本稿では，そのようなスマート形状可変鏡に関して，研究内容を紹介する．&lt;/p&gt;

Copyright © (2017) by International Astronautical Federation. All rights reserved. A mechanism for the high-precision positioning of reflector segments by using kinematic couplings has been developed for balloon-borne radio telescopes, and the effectiveness of the mechanism is demonstrated through experiments. A high-precision reflector for radio telescopes is under development, and it is intended to be used for the observation of radio waves of up to 300 GHz. The reflector consists of six segments, a back structure, and a high-precision positioning mechanism. The high-precision positioning mechanism utilizes kinematic couplings, and the segments are positioned and fixed precisely to the back structure by the kinematic couplings. The positioning of the segments on the back structure is one of the largest sources of error in reflector systems. Therefore, kinematic couplings are important components of a reflector system for achieving a high surface accuracy. Three combinations of a ball and a V-groove are employed in the positioning mechanism. Load-applying mechanisms are used to apply and control pressing loads between the segment and back structure. In order to demonstrate the effectiveness of the mechanism, the positioning repeatability between a segment and a back structure was investigated through experiments. In these experiments, the reflector segment was attached to and detached from the back structure, and the relative positions of the reflector with respect to the back structure were measured using a photogrammetry system during the process of attachment. The cycle of attachment, measurement, and detachment was repeated five times, and the positioning repeatability was evaluated. A positioning accuracy of approximately 20 um RMS was achieved using the developed reflector system. The results demonstrate the effectiveness of the positioning mechanism, which incorporates kinematic couplings for the high-precision positioning of a reflector for a balloon-borne radio telescope.

第32回宇宙構造・材料シンポジウム（2016年12月9日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000087012レポート番号: A11

第32回宇宙構造・材料シンポジウム（2016年12月9日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000087016レポート番号: A15

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. The present paper reports the results of shape-control experiments using the smart secondary reflector prototype for satellite-borne radio-astronomy. The shape of the secondary reflector is modified by six special piezoelectric actuators with displacement magnification mechanisms. The experiments successfully demonstrated that the reception power of the antenna system has been improved by the shape control.

<p>ASTRO-H (hitomi) was an X-ray astronomy satellite in Japan which was launched on 17 Feb. 2016. To meet its science goals, four kinds of instruments and six detectors were equipped on the satellite. The focal length of two soft X-ray telescopes was 5.6 m, and that of two hard X-ray telescopes is 12m. One of the most difficult challenges for the satellite structure was to meet the alignment requirements for instruments and detectors. Through the ground tests and observation results on orbit, it was confirmed that the performance of alignment meet the requirements. In this paper, the results of on-orbit alignment performance of the instruments and obtained techniques to control the alignment are reported.</p>

第31回宇宙構造・材料シンポジウム（2015年12月8日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000047027レポート番号: B13

To realize structure systems of future high-precision space observation satellites, smart structure systems which measure and correct their configuration or/and suppress their vibration on obit have been studied. Among sensors and actuators to be used in the smart structure systems, piezoelectric materials are expected to be a good candidate since they have less mechanical parts and high compatibility for space environment. When a shape of a smart space structure is controlled by the piezoelectric actuators attached to its structural element, electric voltage must be continued to be applied to retain a desired shape. To save the amount of electricity usage, a new control method was proposed and its feasibility was examined in the previous papers [Ikeda and Takahashi, Proc. SPIE 8689; Ikeda et al., Trans. JSASS 12 ists29]. In the method the hysteretic behavior of piezoelectric actuators was utilized effectively. The results showed that displacement of a smart beam with a piezoelectric ceramic actuator bonded remained without any voltage applied to the actuators after a pulsed voltage was applied. However, the displacement of the beam overshot a final position. In this paper this overshoot is suppressed. To this end another type of piezoelectric actuator showing almost no hysteretic behavior is bonded on the beam opposing the actuator showing the hysteretic behavior. Result shows that the overshoot can be suppressed by applying a feedback plus feedforward control to the additional actuator while the pulsed voltage is applied to the actuator showing hysteretic behavior.

© 2015, American Institute of Aeronautics and Astronautics Inc. All rights Reserved. ASTRO-H is a next-generation X-ray observatory satellite planned for launch in fiscal 2015. Because ASTRO-H is a large structure and requires precise and accurate pointing, an understanding of on-orbit thermal deformation behavior is particularly important to the success of the ASTRO-H mission. In the conventional technique for predicting thermal deformation, testing is performed in a thermal vacuum chamber so asto simulate the temperature distribution on orbit. However, when using this conventional technique it is difficult to observe the detailed characteristics of the tested structures due to the limits of the applied temperature distribution cases. To overcome this problem, we propose a new evaluation technique for ASTRO-H. In our technique, on-orbit prediction of thermal deformation is performed thorough numerical simulation using a finite element (FE) model. The validation and correlation of the FE model are carried out by comparing results with thermal deformation test data collected in advance. This technique is especially suitable for satellites that are exposed to various thermal conditions on orbit. Using this technique, we confirmed all of the requirements for on-orbit pointing accuracy and precision in ASTRO-H.

Recently, structural requirements for observation accuracy of satellites&#039; instruments become increasingly high. This research proposes a new pointing control system which uses Stewart platform with elastic hinge. As a linear actuator, artificial thermal expansion of rod is utilized. This system is highly reliable and enables precise control with 6 DOF. We designed the shape control system whose size is about 300mm on each side. By finite element analysis, it is shown that the shape control system can generate translational motion which is over 100μm in the horizontal direction and 20μm in the vertical direction without rotation. Finally, it is confirmed that relative error between analysis and experimental values is within 15% or less when the displacement is more than 100μm from experiments.

This paper discusses the configuration of design of smart space reflector system for realization of future high-accuracy antenna in space. This study aims at establishing of design methods for a smart secondary reflector to correspond to deformation mode which caused on the primary reflector surface in space. Authors have investigated effects that perturbation of Kinematic Coupling (KC), which restricted the primary reflector and a back structure, affecting to the primary reflector surface by using finite-element method (FEM). Furthermore, the number of piezoelectric actuators of the back of secondary reflector surface is varied to compare deformation modes of secondary reflector surface with that of primary reflector. Through correlations of deformation of the primary reflector and configuration of the smart secondary reflector, new knowledge of antenna system while considering two reflectors at the same time is obtained.

© 2015, American Institute of Aeronautics and Astronautics Inc. All rights reserved. This study clarifies the effect of thermal deformation in the reconfigurable space reflector system, through a series of experiments in a thermostatic chamber using a prototype of reconfigurable space reflectors. This study then discusses possible countermeasures against precision degradation of such system due to the thermal deformation, exploiting a finite- element model that is tuned to the experimental results. Though reconfigurable reflector systems inherently have the mismatch in the coefficients of thermal expansion among their structural members, the effect of the mismatch may be minimized by a proper combination of several materials. The prototype used in this study is designed as a preliminary model of a secondary mirror for future radio astronomy satellites.

The present paper reports the results of shape-control experiments using the smart secondary reflector prototype for satellite-borne radio-astronomy. The shape of the secondary reflector is modified by six special piezoelectric actuators with displacement magnification mechanisms. The experiments successfully demonstrated that the reception power of the antenna system has been improved by the shape control.

本研究では,機能分化した複数衛星群によるミッション遂行という新しいシステム概念の提案を行う.従来一つの衛星内に搭載されていたバス部とミッション部を,機能分化させて,複数の単機能衛星に分ける.個々の衛星を単純な単機能衛星にすることで,各衛星の開発のコスト・スケジュールの軽減およびシステムのロバスト性の向上が期待される.さらに,バス機能衛星を特定のミッションに特化したものではなく,汎用的なものとすることで,宇宙におけるインフラシステムとして機能させ,新たに開発するミッション衛星の設計制約を小さくする.機能分化による単純化に加えて,複数の同種の単機能バス衛星の運用は,システムの更新を逐次行えるなど,長期運用におけるメンテナンスの可能性を広げる.ここでは,ミッション衛星の例として,天体観測衛星を想定し,発電機能,通信機能,熱制御機能に特化したバス衛星群による宇宙インフラシステムを検討した.これらのシステムのラグランジュポイント周辺のハロ軌道におけるフォーメーションフライトによる運用を想定し,システムの成立性の評価した.

本研究では、衛星搭載用の形状可変副鏡の初期検討モデルの熱試験において観察された既報の事象について、その発生メカニズムを数値モデル解析を用いて明らかにする。著者らは100GHz程度の電波天文観測を想定し、軌道上で主鏡の歪み等の原因で発生する電波の光路長誤差を、副鏡を能動的に変形させることで軽減するシステムの開発を行っている。形状可変副鏡の初期検討モデルの熱試験を実施したが、恒温槽内の試験では計測できる項目が限定的であり、計測データだけから現象を定量的に説明することが難しい。そこで本研究では有限要素解析を実施して実験結果を再現することを通し、特に材料の熱膨張係数の不整合が形状可変副鏡の性能に与える影響を明確化する。

第30回宇宙構造・材料シンポジウム（2014年12月1日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000043001レポート番号: A01

An efficient estimation method for thermal properties is presented, where elements of thermal conductive matrix are considered as estimation parameters. Linear heat balance equations in vector-matrix form are rearranged as least square equations of estimation parameters, where the coefficient matrix and the right-hand side vector are composed of temperature data and derivative of temperature data. Transient thermal test data in steady-state thermal tests are effectively used to construct these equations. A simple numerical example is presented to validate the effectiveness of the presented method.

Pointing performance of the truss structure on orbit which is used for large space telescope is discussed. To achieve advanced science missions, large and precise support structures such as truss structures are needed. However, the preciseness of the structure might be lost due to various disturbances on orbit. Therefore, to realize ultra large and precise support structures, active shape control of the structures is needed. To control the shape, we use artificial thermal expansion caused by heaters instead for mechanical actuators. Control systems without mechanism have high reliability, which is very attractive to use on orbit. However, there are some constraints in the usage of heaters. To improve the control performance under such constraints, we apply "Model based Predictive Control (MPC)" as feedforward control method with preview information. In this paper, we mainly show the effectiveness of MPC compared PI control, which is one of the typical feedback control methods. We constructed structural mathematical model and thermal mathematical model in order to show performance of control system. It is confirmed that total error is decreased by MPC compared with the case of PI control through 'numerical simulations.

The Soft Gamma-ray Detector (SGD) is a Si/CdTe Compton telescope surrounded by a thick BGO active shield and is scheduled to be onboard the ASTRO-H satellite when it is launched in 2015. The SGD covers the energy range from 40 to 600 keV with high sensitivity, which allows us to study nonthermal phenomena in the universe. The SGD uses a Compton camera with the narrow field-of-view (FOV) concept to reduce the non-Xray background (NXB) and improve the sensitivity. Since the SGD is essentially a nonimaging instrument, it also has to cope with the cosmic X-ray background (CXB) within the FOV. The SGD adopts passive shields called "fine collimators" (FCs) to restrict the FOV to &lt;= 0.6 degrees for low-energy photons (&lt;= 100 keV), which reduces contamination from CXB to less than what is expected due to NXB. Although the FC concept was already adopted by the Hard X-ray Detector onboard Suzaku, FCs for the SGD are about four times larger in size and are technically more difficult to operate. We developed FCs for the SGD and confirmed that the prototypes function as required by subjecting them to an X-ray test and environmental tests, such as vibration tests. We also developed an autocollimator system, which uses visible light to determine the transmittance and the optical axis, and calibrated it against data from the X-ray test. The acceptance tests of flight models started in December 2013: five out of six FCs were deemed acceptable, and one more unit is currently being produced. The activation properties were studied based on a proton-beam test and the results were used to estimate the in-orbit NXB.

To keep a shape of a smart structure with piezoelectric actuators bonded on it, electric voltage must be applied continuously. To reduce the amount of electricity usage, a new control method was proposed and its feasibility was examined in the previous studies [Proc. of SPIE 8689 86890C, Proc. of 29th ISTS 2013-c-40]. In this method hysteretic behavior of piezoelectric actuators in strain-electric field relationship was utilized effectively, which behavior is that some amount of strain remains even at zero voltage once a large voltage is applied. The results showed that displacement of a smart beam with a piezoelectric ceramic actuator bonded remained without applying voltage to the actuators after applying a pulsed voltage. However, the displacement overshot a final position while applying the pulsed voltage. That is generally undesirable. In this paper a suppression method of this overshoot was proposed. To this end another piezoelectric actuator was bonded on the beam opposing the original actuator. The original actuator was a soft type while a hard type piezoelectric actuator was used as the opposing actuator. With help from the two types of actuators, the overshoot could be suppressed while applying the pulsed voltage by controlling the voltage for the opposing actuator adequately, and a desired displacement could be obtained at zero voltage after the pulse.

This paper experimentally evaluates the shape-control performance of the prototype of smart reconfigurable reflectors, and proposes an updated design that will ameliorate the problems identified in the experiments. The prototype is a preliminary model of a secondary mirror for future radio astronomy satellites. The prototype can control the shape of a 300mm-diameter CFRP mirror, using six piezoelectric actuators integrated with displacement-magnification mechanisms.

An efficient scheme for steady-state thermal temperature prediction in vacuum tests is presented. First, heat balance equations of spacecraft thermal mathematical models are analytically solved without nonlinear radiation terms. Then, perturbation solutions with radiation terms are deduced. Observation equations based on both linear and nonlinear solutions are presented, which are applied for the least square estimations of steady-state thermal temperature prediction with transient temperature data. A simple experimental result shows the effectiveness of presented scheme.

For future space sciences, there is an increase of the demand of large and precise space structures such as JWST, ASTRO-H and so on. To realize such ultra-large and highly precise space structures, the conventional design concept and development process should be changed drastically. Not only novel materials with high shape stability, but also smart structures which can change their characteristics are promising candidates. In this paper, advanced techniques of structures and materials including smart space structures are summarized.

Smart space structure systems which measure and correct their shape on orbit have been studied as a future high-precision space structure systems. Piezoelectric ceramics are often used as an actuator in the system. To correct and retain the shape of the structure, electric voltage must be applied continuously. To reduce the amount of electricity usage, a new control method was proposed, where a fact that strain remains after a pulsed voltage input due to the hysteresis in strain-electrcic curve of the piezoelectric actuators was utilized effectively. In this paper, feasibility of the proposed method was verified for a piezoelectric ceramic plate and a beam on which the piezoelectric ceramic plate was bonded. The result showed that the strain of the piezoelectric ceramic plate and the tip displacement of the beam remained after the pulse. Although the beam vibrated after the pulse, the vibration was suppressed by applying a feedback control or controlling the shape of the applied pulse input.

宇宙構造物の高精度化のために軌道上で圧電セラミックスアクチュエータを用いてその形状を補正する研究が行われている,軌道上では昼夜の温度差が大きく,熱歪で構造物の精度が低下しないように複合材で製作される場合がある.しかしながら,圧電セラミックスは熱変形するので,その変形が,構造物の精度を低下させたり,制御限界程度になる可能性もある.そこで,熱歪をキャンセルするような圧電セラミックスアクチュエータを提案し,その剛性や圧電特性を評価した.

To meet advanced science missions, large and precise support structures such as truss structures are needed. Temperature and shapes change depending on solar radiation. As a result, the structure lost its preciseness. In this research, pointing accuracy of the truss structure on orbit is discussed. To control the shape, artificial thermal expansion caused by heater is used instead for mechanical actuators. Control systems without mechanism have high reliability because heater has no sliding parts. To maintain pointing accuracy on orbit, preview control method in this paper is expected to be more useful than feedback control methods.

A Conceptual design of "Space Colony" for long-term residence is reported in this paper. As constraint conditions, micro gravity and high vacuum are considered in the structural design. Although such conditions are constraint, they have possibilities to be utilized for further innovative human life style which can not be realized on the ground. Especially, the environmental condition of micro gravity may have great impact to the life style from the viewpoint of mobility and immobility. In this paper, we propose some conceptual designs of the space colony utilizing micro gravity and discuss its characteristics.

A novel measurement apparatus with extremely high accuracy called Laser Displacement-meter with Long-working-distance (LDL) was developed to measure micro-meter-scale deformation of large space structures in the ground test. The combination of a laser source and a position sensitive detector makes it possible to measure accurately with long working distance. It is confirmed that LDL has the performance with 7 μm error at 6.1m working distance through the thermal deformation test of X-ray telescope satellite: ASTRO-H. Because LDL is compact and portable one, it can be applicable for measurement of other large objects such as buildings, bridges, and so on.

Highly precise structural analysis of tension-stabilized space reflectors using geometrically nonlinear finite-element (FE) model usually requires accurate knowledge of the design parameters. However, internal forces in the deformed configuration or temporal change of stiffness parameters are usually unable to be measured; thus, accurate numerical modeling of a tension-stabilized structure is difficult. The present paper describes a methodology to construct a high-fidelity FE model of high-precision gossamer structures by applying a conventional method of FE model updating to a geometrically nonlinear FE analysis. Using the FE model updating methodology, an accurate FE model can be constructed through the estimation of unmeasured parameters. In this study, a simple tension-stabilized beam structure is analyzed for demonstration of the concept. © 2012 AIAA.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-Throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ?E 5 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes. © 2012 SPIE.

To meet advanced science missions, large and precise support structures such as truss structures are needed. In this paper, pointing control of a truss structure is discussed. To control the truss structure, thermal expansion of truss members is utilized instead of mechanical actuators. Heaters are equipped to truss members so that the thermal expansion of the members is controlled by heaters. PI control is applied to an experimental model which is box truss with 1.9m height. Through experiments, it is shown that the truss structure can be controlled with good accuracy, for example, within ...

A large space reflector consisting of radial ribs and hoop cables is considered to satisfy rigorous design requirement of a high shape precision as well as lightweight. Due to difficulty of verification of such a large and high-precision space structure by on-ground testing, a simulation-based verification is required. As the first step of establishment of the simulation-based verification, this research investigates the computational accuracy of several nonlinear finite element codes in comparison of numerical solution based on Elastica for the simplified beam model that allows large deformation. Then, sensitivities of deformation with respect to Young&#039;s modulus and applied load are investigated.

An effective method for sensitivity analysis of uncertain parameters in space reflectors is presented. In the method, the sensitivities of uncertain parameters with respect to structural modes are explicitly derived by utilizing the singular value decomposition of sensitivity matrix, which can predict which modes are excited due to the variation patterns of uncertain parameters. A simple numerical example, the model of which is a radial rib and hoop cable antennas that consists of 60 radial ribs, are provided to verify the effectiveness of the presented method.

In SCOPE mission, flexible extendable rod antennas are equipped along the spin axis of satellite. For the extendable function, STEM (Stowable Tubular Extendable Member) is used as the rod antenna. The apparent natural frequency of the STEM changes depending on the spin-rate. Furthermore, bending and torsion of the STEM are coupled because the STEM has open section. The dynamic characteristics of the STEM are clarified through analysis and tests. Especially, the coupled vibration of bending and torsion, and the effect of spin motion on apparent natural frequency of the STEM are investigated. As a result, it was shown that the effect of spin motion can be quantitatively predicted by simple analytical model. In addition, it was found that the characteristics of the vibration are strongly affected by the boundary condition of the STEM.

Requirement for shape stability of space structures such as barrel for space telescope tends to become more precisely. In addition to it, large size over 10 meters is sometimes required for such support structure to meet advanced science missions. To realize large and precise support structures, comprehensive techniques including prediction, measurement and stabilization techniques on orbit are needed. In this paper, we introduce some fundamental techniques to keep the precise shape for a slender box truss as a representative support structure. The structural deformation on orbit is induced by thermal distribution, disturbance (RW/MW/SAD etc.) and so on. At first, we analyzed temperature distribution and thermal distortion of the truss structure to predict the thermal deformation. The accuracy of analysis results is evaluated through experiments with a five-bay truss structure. Then, system identification is carried out to identify the stiffness of the structure because such identification of the stiffness becomes important for the precise prediction of thermal deformation in the case of indeterminate structure. As a first step, the stiffness matrix is identified by using particle swarm optimization method from the experimental data of natural frequency. By using the identified stiffness matrix, the natural frequency can be estimated within 1% error. At last, we attempt the shape control of truss structure by using artificial thermal expansion. It is experimentally shown that deformation of truss structure could be controlled with good accuracy, for example, within 30μm error for 1.9m height truss. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

Space Inflatable Membrane structures Pioneering Long-term Experiments (SIMPLE) unit is one of ISS Japanese Experimental Module (JEM) Kibo&#039;s exposed facility payloads scheduled to be launched in 2012. Manufacturing and function testing phase of the engineering model (EM) has been completed and the proto-flight model (PFM) is now underway. The SIMPLE mission consists of three experimental verifications using Inflatable Extension Mast (IEM), Inflatable Space Terrarium (IST) and Inflatable Material Experimental Panel (IMP). The combination of the experiments is aimed to demonstrate the usefulne...

In the past decades, extensive researches about space structures have taken place in Japan from conceptual studies to practical mission studies. The recent holy grail of space structures is to establish the ultra-light, large and stable space structure with high precision and high packaging efficiency that is &quot;Gossamer&quot; space structure. This paper presents the summary of Japanese recent activities for the past several years for space structures research, and they are classified into five major divisions in this survey paper; concept, design, application, analysis, and experiment/test. On the whole, membrane and cable mesh structures have been studied intensively. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

Tethered-Solar Power Satellite (Tethered-SPS) consists of power generation/transmission panels suspended by tether wires. The most important feature of the Tethered-SPS is that it is constructed by perfectly equivalent power generation/transmission units. Each unit panel, 100 m × 95 m, is suspended by four 5 km-tether wires deployed from a bus unit. The weight and output power of the unit SPS are 42.5 MT and 2.1 MW, respectively. The engineering studies have been conducted to design the power generation/ transmission panel and to show how to deploy the panel. In addition to the engineering research, two major environmental issues, the effect of hyper-velocity impact of the debris or meteoroids and the interaction of the solar cell array with the ambient plasma, have been studied. The engineering studies have shown that the power generation/transmission panel is technically feasible using the near-term technologies. The environmental studies have shown preliminary guidelines to design the power generation/transmission panel.

&quot;HIT-SAT&quot; is a small satellite to demonstrate performance of the bus systems of &quot;Hokkaido Satellite&quot;. The main purpose of the attitude control system of &quot;HIT-SAT&quot; is to get basis data for the attitude control and determination system of &quot;Hokkaido Satellite&quot;. &quot;HIT-SAT&quot; was launched on Sep. 23, 2006 by M-V-7. Attitude control system of &quot;HIT-SAT&quot; could get magnetometer data and gyro data on orbit. This paper describes the attitude determination from magnetometer data obtained on orbit.

HIT-SAT has been designed and developed in order to examine functions of the bus system. It was successfully launched by M-V rocket #7 on 23rd September 2006. The volume and weight of HIT-SAT are about 12[cm^3] and 2.7[kg], respectively. HIT-SAT has a flame-panel structure that consists of 6 panels, 4 columns and 2 shelves made of the aluminum alloy that has a high conductivity. The passive thermal control is adopted. Thermal analysis was conducted using Thermal Desktop/SINDA/FLUINT before launch. However, the result of thermal analysis is quite different from on-orbit thermal data of HIT-S...

A CubeSat size class &quot;HIT-SAT&quot; is a micro satellite that developed by Hokkaido CubeSat development team. Its volume and weight is 2.7kg and 12cm cubed. It was fixed in the sub payload space of M-V-7, and was ejected after main satellite separation on September 23,2006. The orbit is sun-synchronous orbit of the altitude of 279-660[km] and the inclination of 98.32[deg]. The purpose is to examine some functions of the bus system. This research report describes an electric al power subsystem design. The major difficulty of Electrical Power System is surely OFF and ON. The OFF needs to be guaran...

HIT-SAT has been designed and developed in order to examine functions of the bus system. It was launched by M-V-7 into a sun-synchronous orbit of the altitude of 279-660 [km] and the inclination of 98.32 [deg]. The volume and weight of HIT-SAT are about 12×13×12[cm3] and 2.7[kg], respectively. HIT-SAT has a flame-panel structure that consists of 6 panels, 4 columns and 2 shelves made of the aluminum alloy that has a high conductivity. The load pass at the launch is their panels and columns. The passive thermal control is adopted. Random vibration tests and impact tests were carried out. It ...

The HIT-SAT had been developed by Hokkaido in order to demonstrate the performance of the attitude control system for &quot;Hokkaido Satellite&quot;. &quot;Hokkaido satellite&quot; is a 50kg small satellite, and the main mission is a remote sensing. The HIT-SAT is size 12cm cubed and weight 2.7kg. Attitude Control is an object of keeping satellite attitude by spin stabilization. It has three parts as de-spin, spin-up and sun acquisition. As an Attitude sensor, we adopt Sun sensor, Magnetometer, and GYRO. Actuator is 3-axis Magnetic Torquer. The HIT-SAT was launched successfully on September, 23, 2006(JST) as a...

&quot;Hokkaido satellite&quot; is a 50kg small satellite, and the main mission is a remote sensing. The HIT-SAT had been developed by Hokkaido in order to demonstrate the performance of the attitude control system for &quot;Hokkaido Satellite&quot;. The HIT-SAT is size 12cm cubed and weight 2.7kg. Attitude Control is an object of keeping satellite attitude by spin stabilization. The HIT-SAT was launched successfully on September, 23, 2006(JST) as a sub-payload of the M-V-7 Rocket. In this paper, we described a design of data handling unit for the HIT-SAT and the result in orbit.

A CubeSat size class &quot;HIT-SAT&quot; is a micro satellite that developed by Hokkaido CubeSat development team. Its volume and weight is 2.7kg and 12cm cubed. It was fixed in the sub payload space of M-V-7, and was ejected after main satellite separation on September 23, 2006. The orbit is sun-synchronous orbit of the altitude of 279-660 [km] and the inclination of 98.32 [deg]. The purpose is to examine some functions of the bus system. This research report describes an electric al power subsystem design. The major difficulty of Electrical Power System is surely OFF and ON. The OFF needs to be gua...

For earth observation thorough hyper-spectral camera, a small satellite &quot;Hokkaido Satellite : TAIKI&quot; has been designed in Hokkaido. To demonstrate the performance of the bus system, a cube-sat &quot;HIT-SAT&quot; was developed as a scale model of the Hokkaido Satellite This paper describes the development and results of launch and operation. The HIT-SAT is 2.7kg and 12cm cubed. The bus system of the satellite consists of five subsystem; power generation system, structure system, data handling system, communication system and attitude control system. The HIT-SAT was launched successfully on Sep. 23, 2...

HIT-SAT was launched as a sub-payload of the M-V-7 rocket on September 23, 2006. The orbit of HIT-SAT is the elliptic one with 98 deg inclination. Altitude at apogee is 648km and perigee 279km.The satellite is operated by the ground station set up by Hokkaido Institute of Technology. The mission of HIT-SAT is to demonstrate the commercial-off-the-shelf component on the orbit. HIT-SAT is an amateur satellite where the amateur radio machine was installed. Operation is being done well on the orbit as for HIT-SAT now. This paper describes the system of the ground control station of HIT-SAT.

Tethered Solar Power Satellite (Tethered-SPS) has been proposed as a feasible and practical Solar Power Satellite. It consists of a power generation/transmission panel suspended by tether wires deployed from single or multiple bus satellite. Especially, the multi-bus Tethered-SPS, recently invented, is highly flexible and expandable. It can be constructed by integrating perfectly equivalent units of miniature Tethered-SPS connected to each other. Each unit folded up is transported from the ground to the geo-stationary orbit and deployed automatically. This concept enables phased construction approach, evolutional development scenario, and coexixtence with other geostationary satellites.

For large space structures, the deformation of the structure due to thermal stress affects the attitude motion. In this paper, we propose a modularized structure which can release the thermal deformation locally. As an application, we study a space solar power system which is stabilized by gravity gradient torque. The purpose of this paper is to suppress overall deformation by the local release of thermal deformation. At first, we analyze thermal deformation of the structure and induced attitude motion under the condition where connecting rigidity between modules is as stiff as module itself. From the result, it is shown that roll and yaw motion becomes unstable due to the thermal deformation. Then, we modify the condition of the connection between modules to release thermal deformation locally. Through the simulation, it is confirmed that large deformation can be suppressed in the modified modularized structure, and thermally induced attitude motion becomes small enough for the mission.

This paper describes the design and performance verification of the attitude determination and control system for the Hokkaido Satellite. The main missions of the satellite are earth observation during sunlight and laser communication during sunshade. The purpose of the attitude determination and control system is to stabilize the attitude around three axes within three degrees. The satellite is stabilized by a momentum wheel (MW). The attitude determination system consists of an earth sensor and an inertia reference unit (IRU). Based on the Kalman filter, the determination system can estimate three attitude angles and IRU bias rates without a yaw sensor. The control modes of the satellite are an attitude acquisition mode, a normal mode and a safe-hold mode. For the normal mode of the wheel-stabilized earth pointing satellite, a new pointing control law is proposed. The proposed law simultaneously achieves nutation dumping and angular momentum direction control relative to the orbital coordinate system. The control law consists of pitch angle control by MW, roll and yaw axes control by magnetic torquers (MTQ) and angular momentum control by MTQ. Through numerical simulations, it was confirmed that the determination laws and the control laws can achieve the required attitude accuracy and stabilization time.

Hokkaido satellite is the small satellite which is being developed in Hokkaido. In this paper, the attitude determination system based on the Kalman Filter is designed for the Hokkaido satellite. The satellite has an earth sensor and IRU. The earth sensor outputs roll and pitch angles. Focusing on coupling between roll and yaw axes in kinematic equation of earth observation satellites, the attitude determination system is designed to estimate roll, pitch and yaw angles using roll and yaw angular measurements and IRU. We estimate accuracy of sensors to satisfy Hokkaido satellite&#039;s requiremen...

Tethered Solar Power Satellite (Tethered-SPS) consisting of a large power generation/transmission panel and a bus system which are connected by tether wires has been proposed as an innovative solar power satellite. The concept Tethered-SPS is highly robust and potentially low cost. This paper presents a new version of Tethered-SPS which is integrated by perfectly equivalent units loosely connected to each other. The new Tethered-SPS, highly flexible and expansible, has a lot of advantages over the past SPS models in attitude stability, construction, modularization, thermal characteristics, and robustness.

In Hokkaido, engineers in companies and researchers in universities have developed a small satellite, Hokkaido Satellite, since two years ago. This paper describes a designed attitude controll system based on Hokkaido Satellite&#039;s requirement. Bias momentum controll is applied to stabilize the attitude of satellite around three axises. The satellite has a momentum wheel on pitch axis and two reaction wheels on roll and yaw axises. Magnetic torquers are aligned with three axises. We simulated the designed attitude control system in complex environment where there are magnetic field, gravity, ...

It has been difficult to avoid falling over for walking robot with only legs. However, by adding arms, the robot is possible to transit from biped walking to more stable quadruped walking when the robot cannot maintain biped walking We demonstrate the limit of stable gait and that the robot can maintain locomotion through the transition to stable quadruped walking despite applied external force.

A biological binocular stereo vision processing was modeled based on Pulse-Coupled Neural Network(PCNN). Then disparity detection can be accomplished in the spontaneous synchronization of neurons corresponding to the correct matching points. Consequently, it is clarified that binocular stereo vision is generated through proposed model. Furthermore, our model is appropriate model based on actual visual processing of biology.

A novel method for extraction of moving objects in an image sequence using multi-tiered Pulse-Coupled Neural Network (PCNN) is presented in this paper. PCNN is a biologically-inspired model which shows highly applicable in various image processing applications, including image segmentation, contour detection, etc. In order to adapt PCNN for moving object extraction, the multi-tiered PCNN model is proposed. This new PCNN model is called E-PCNN, since excitatory term and external linking are its two features. The architecture and algorithm of E-PCNN are presented in detail. It is shown that E-PCNN outweighs the commonly used inter-frame difference algorithm, having three main advantages: utilization of multiple color information, parameter robustness and robustness against noise.

The stability analysis of large space structures such as space solar power system is discussed in this paper. Because these structures are very large and flexible, the mutual interference among position, attitude and structural deformation cannot be negligible. Therefore, a comprehensive analysis of the system dynamics including position, attitude and structural deformation on orbit has been required. In this study, we propose a new method based on potential energy to estimate the integrated stability. Based on potential energy, the integrated stability of deviations in position, attitude and structural deformation on orbit is analyzed. The potential energy, which is caused by gravitational force and centrifugal force, is considered as well as strain energy of the structure. By using the potential energy, not only equilibrium states but also the degree of stability in the neighborhood can be estimated. As a case study, we focus on a solar-array platform with gravity gradient stabilization. At first, the stability about the position and attitude is estimated based on the potential energy. As compared with the numerical results of system dynamics, the validity of the estimation is confirmed. Then, we show the change of stability which depends on the satellite&#039;s configuration. Finally, the stability of structural deformation around the equilibrium point is shown through the potential energy.

Electric wheelchair is an important device to the physically handicapped persons with mobility. The aim of our study is to develop the electric wheelchair which is driven as the human intention, and we tries to extract the human intention from the adaptability of physical characteristic between embodiment system and wheelchair system in various situations. To design the system, we developed the experimental electric wheelchair which can measure dynamic posture changes of electric wheelchair and passenger, simultaneously. These measurements are carried out the straight-line motion and turning motion, etc. Results are shown the various posture change of passenger under the some conditions, and the hunting phenomenon as example of uncontrollable situation. We also derive a mathematical model to analyze this phenomenon, and we explain the simulation results. Finally, we discuss the methodology to realize adaptive operation to human intention.

インターネットを媒体としたロボット遠隔操作システムの構成を提案する。ロボットに行わせるタスクにより各種データの重要性の序列が変化することを利用し, 輻輳検出時にデータの送信頻度を変化させ幅輳適応, 操作の安定化を図る。

筋電図のヒューマンインタフェース (HI) 利用における問題として, 識別には十分大きい能動的な筋力を必要とすることがあげられる。本研究では, 能動的な筋力を必要としないHIを実現するために, 筋刺激応答を応用することを考える。

本研究では, 汎用の加速度センサとPC, およびlinuxを用いた情報ネットワークシステムを提案する。危機管理や状態の把握といった観点から電動車いすでの運用について述べる。遠隔操作やユーザ識別等の展望についても詳述する。

It is known that the passive walking is generated by a biped mechanism which can walk down a gentle slope. Though the suitable parameters are necessary for stable walking, the simulated walking has three major characteristics : the period doubling bifurcation, the attractor basin into stable walking, and the chaotic behaviors. The chaotic behavior appears when the slope exceeds a certain value. In this paper, focusing on these three characteristics, we show the dynamic structure of the biomechanical chaos generated by the 4-link walking robot with knee, and discuss about the relation to the human walking.

本研究ではスパイク間隔がカオス的ダイナミクスを持つパルス結合ニューラルネットワーク(PCNN)を構成し, そのカオス的同期現象について数値計算を元に解析を行った.具体的には, 2体結合系における同期条件の解析及び局所的興奮-大域的抑制型の結合を持つ1次元結合系における同期集団形成について検討した.1次元結合系に局所的な同期集団が複数形成された場合, ダイナミクスがカオス的なときは, 互いに異なる同期集団に属するニューロンのスパイク系列間には相互相関を持たないことが確認された.これらの結果から視覚処理過程のテンポラル・コーディングにおけるカオスの役割について検討した.カオス的なスパイク間隔を用いることでより多様な情報表現ができる可能性が確認された.

We have proposed a chaotic pulse coupled neural network (CPCNN) to investigate possible roles of high-dimensional chaotic dynamics in information coding using synchronous oscillation. In the present paper, some basic characteristics of CPCNN are examined. On the one hand, in a two-neuron system, CPCNN have rather simple condition for the persistence of synchronization despite of its chaotic dynamics. On the other, in a one-dimensional lattice system of homogeneous neurons, it can exhibit complex and various dynamics such as dynamical clustering, traveling waves and spatio-temporal intermittency.

Based on the analogy of heat and wave equations, novel decentralized control methods of a redundant manipulator are proposed. Because these control methods are based on real physical phenomena, physical sense of control parameters can be understood intuitively. Some traditional control methods can be reconstructed from the viewpoint of proposed methods. Furthermore, stable characteristics of the heat conduction imply stability of the control method. As case studies, three subjects are discussed: position control of the end-effector of manipulator, obstacle avoidance, grasping behavior. Some numerical results are shown to illustrate capabilities of proposed control methods.

本研究では, Global Entrainmentという概念に基づいて, 2足ロボットの歩行運動を生成することに焦点をあてる。その概念によると, 歩行運動は, 神経・身体・環境からなる結合力学系におけるリミットサイクルアトラクタとして自己組織される。本論文では, 計算機シミュレーションならびに実機実験において, 同概念に基づく歩行生成に成功したので報告する。またシミュレーション上では, その歩行が身体・環境モデルの変動に対して適応能力を持つことも調べる。

人-車椅子系の動的制御モデルの構築を行い, 操作性の向上のための資料を得ることを目的に, 本研究では, 人が搭乗している時の電動車椅子の動的な姿勢変化を計測し, その定量的な評価を行った。車椅子には, ヨー, ピッチ, ロールの3軸の角速度と加速度が計測できる姿勢センサーを取り付け, 搭乗者には頭部用の3軸加速度センサを装着して計測を行った。実験は, 発進・走行・停止の直線加減速運動, カーブ走行, その場旋回などの計測を行い, 人-車椅子の姿勢変動の相関を評価した結果を示した。

電動車椅子ロボットにおける人の上半身姿勢の制御を行う。本研究では, 前後左右の2自由度を持つ倒立振子モデルにより人の上半身を表す。急な加減速において, 電動車椅子上の人の上半身姿勢が不安定になることは既によく知られているが, この姿勢変動を横方向も含めて安定化することは非常に困難である。ここでは, 上半身の質量, 長さ等のの身体パラメータが未知である場合に対して, 部分的適応制御を適用し, 姿勢安定化を行う。数値計算によって, その有効性を示す。

In this paper, we show usefulness of Pulse Coupled Neural Network(PCNN) in visual information processing. The PCNN is based on the visual information processing of mammals, and has superior ability like segmentation, edge detection, time resolution, and so on. Therefore, we apply the PCNN to the some visual problems in engineering such as stereo vision, recognition of handwritten characters, and object detection. Each simulations use features of the PCNN, such as robustness against noise, detection ability of foveation point, and segmentation ability using color and form information. Various results of the simulations and usefulness of PCNN are presented.

An autonomous distributed control is introduced as a new control method. The effectiveness of the control is verified using a case study, where the control method is applied to the control of variable geometry trusses that has high redundancy. Through computer simulations, it is shown that various behaviors of variable geometry trusses are realized by very simple control rules of subsystems.

キネマチックカップリングにおけるラッチ完了条件の理論式の妥当性を実験的に確認し，その成果の報告をInternational Symposium onSpace Technology and Scienceにて行った．また熱サイクル負荷時における結合界面での滑りについての評価を行い，サーマルスナップの発生要因とその関係性についての検討を行った．熱変形に関しては，周期的な熱入力を加えることで，周波数空間上での要因分離を行い，外的環境に対して，ロバストな試験方法の提案・実証をした．最後に，固着の主要因の一つである摺動の低減を狙い，転がりによる無摺動関節機構を検討し，その概念設計を行った．電磁石の実装によって，着脱も可能となり，ジェンダーのコントロールも容易に実施が可能となる．

展開構造物のジョイントラッチ部の機械特性として，剛性および熱変形時のラッチ部の滑りに関する研究を行った．各部材の剛性が全体剛性に与える感度を評価し，ジョイント部の剛性寄与度が高いことを明らかにした．また，これらのジョイント部のクリアランスの時間的な変化によって振動が誘起されること明らかにした．熱変形時のカップリング面での滑りに関しては，特に押付力に注目し，その滑り量を管理することを試みた．適切な押付力を電磁石によって制御することで，カップリング面での滑りを管理することが可能となり，展開構造物の形状精度の向上につながることを示した．

宇宙大型展開構造物の位置決め機構であるキネマチックカップリングや展開アンテナの展開再現性についての研究を実施した．前者では，結合界面に働く摩擦力をパラメータとして，ラッチが完了する許容摩擦力をカップリング傾斜角の関数として導出し，その妥当性を実験により確かめた．加えて，振動を印加することで，ラッチ未完了に推移させること試みた．摩擦係数と押付力の関数として，加えるべき振動荷重を導出し，実験により完了状態へ移行できることを確かめた．展開アンテナに関しては，ジョイント部の摩擦起因の展開非再現性について，地上重力環境下での評価方法を確立した．