JP4077710B2 - Space stabilization device - Google Patents

Description

【００１１】
ここで、Xi、Yiは各指向軸決定要素１０〜１３の光学主軸に垂直な局所座標であって、例えば像面検出器１１のXIM軸はペイロード３のX軸と平行な軸、YIM軸はペイロード３のZ軸方向に平行な軸である。また図１の構成では、主鏡１２、副鏡１３のXi軸、Yi軸はいずれもペイロード３のX軸、Y軸と平行であり、駆動鏡１０のXi軸はペイロード３のX軸と平行、Yi軸はペイロード３のY軸をX軸回りに時計回りに45°だけ傾けた軸である。また、式中のaXXi、aYYi、bXYi、bYXiは、光学系によって決まる係数であり、それぞれ指向軸決定要素iの回転変動φXi、φYi、並進変動δYi、δXiに対するX軸またはY軸回りの指向変動ΔθX、ΔθYの感度を示す。
ただし、指向誤差および並進・回転変動は微小量であるとして、線形近似を行っている。また、ペイロード指向軸４のZ軸回りの回転は、像回転に対応していて、空間安定化装置によっては像回転に対する空間安定も必要とされることがあるが、ここでは制御の対象外とする。
【００１２】
なお、より一般的な光学系構成に対しては、光学系を構成する各要素（指向軸決定要素）の慣性系１に対する並進・回転の変動量（δXi、δYi・φXi、φYi）と指向変動（ΔθX、ΔθY）との関係は、以下の関係式で表される。この場合も微小量に対する線形近似を行っている。
【００１３】
【数２】

【００１４】
また、像回転に対する空間安定が要求される場合、像回転に対応するペイロード指向軸４のZ軸回りの変動を含めると、以下の関係式となる。
【数３】

【００１５】
次に、指向軸決定要素１０〜１３の慣性系１における並進および回転変動（δi，φi）を、各指向軸決定要素１０〜１３上に設置した慣性センサ６の出力から測定する具体的方法について説明する。ここで、慣性センサ６とは、物体の慣性系１に対する並進運動情報（位置、速度、加速度等）または回転運動情報（角度、角速度、角加速度等）を検出するセンサの総称である。具体的には、並進運動情報を検出する加速度計や、回転運動情報を検出するジャイロ、ジッタセンサ（角度、角速度等を検出する広帯域の特殊センサ）等を指す。
図２（ａ）、図２（ｂ）は、指向軸決定要素１０〜１３上の慣性センサ６の２種の配置例を、平面図および側面図で示すものである。図２（ａ）は、指向軸決定要素の反射面の裏面側に配置される例を、図２（ｂ）は、指向軸決定要素の側面に配置される例を示す。いずれの配置においても、慣性センサ６として1軸加速度計を使用している。図中、矢印はセンサの感度軸方向を示し、黒丸はセンサが紙面に垂直前方に感度を持つことを示す。また、A（Axialの頭文字）は感度が軸方向（Z軸方向）、R（Radialの頭文字）は感度が半径方向、T（Tangentialの頭文字）は感度が接線方向をそれぞれ向くように配置されたセンサである。
【００１６】
これらの加速度計（慣性センサ６）の出力（aA1、aR2のように加速度を表すaにセンサの識別名を添字で付けて示す）から、指向軸決定要素のX、Y方向の並進加速度δ"Xi、δ"Yiおよび回転角加速度φ"Xi、φ"Yiを、以下の数式により求めることができる。ただし、’は１階の時間微分を、”は２階の時間微分を示すものとする。簡単のため添字iは省略し、さらに各指向軸決定要素の基準面（例えば、平面鏡の反射面）とセンサ設置点間のZ方向の距離は、rに比べて小さいとして無視している。
【００１７】
図２（ａ）に示す配置では、
【数４】

また、図２（ｂ）に示す配置では、
【数５】

【００１８】
この場合、慣性センサ６として1軸加速度計を使用した例を示したが、上述したように、角速度や角度変動を直接計測できる各種のジャイロやジッタセンサ等を使用してもよく、φ"iの代わりにφ'iやφiが計測される。慣性系に対する速度δ'iや変位δiを検出できる慣性センサの適当なものは少ないが、後述する相対センサを用いる方法によれば、検出可能である。
空間安定の場合は、動揺に伴う指向変動を抑えることが目的であるから、δiやφiの変動成分すなわちAC成分を知ることが重要であり、一定値すなわちDC成分は必ずしも必要としない。このため、各指向軸決定要素iの並進加速度δ"i（あるいは速度δ'i）と回転角加速度φ"i（あるいは角速度φ'i）が得られれば、積分は常に可能であり、これらを時間積分してδiやφiを得ることは容易である。
また、並進加速度δ"i（あるいは速度δ'i）や回転角加速度φ"i（あるいは角速度φ'i）を積分しないで、並進・回転の変動量（δi、・φi）と指向変動（Δθ）との関係を示す上記数式「数２」「数３」の両辺を１階または２階時間微分した以下の数式を用いても良い。
【００１９】
【数６】

【数７】

【００２０】
この場合、数式「数６」「数７」により指向変動Δθの１階または２階時間微分値Δθ'またはΔθ"を得て、これをこのままの形、あるいは１階ないし２階積分したΔθ'、Δθの形で、空間安定化制御に使用する。制御系を構成する観点からは、むしろこの方が有力である。さらに、複数の異種センサを組み合わせて（例えば、ジャイロと加速度計、地磁気センサの組み合わせ）、広帯域でかつDC成分も出力できるようにしても良い。
【００２１】
以上に詳細に述べたように、各指向軸決定要素１０〜１３に設置した慣性センサ６により、各指向軸決定要素１０〜１３の慣性系１における並進および回転変動（δi，φi）を測定することによって、ペイロード３の指向変動Δθが演算できる。このような演算処理により、図１に示す指向軸変動推定部７では、各慣性センサ６の検出情報を入力として、ペイロード指向軸４の指向変動Δθを推定する。
【００２２】
図３に、空間安定化制御の制御動作を機能ブロック図で示す。
プラットフォーム２の動揺５に伴って、ペイロード３を構成する各指向軸決定要素１０〜１３は、剛な一体構造でない限り一般に相異なる並進・回転変動を行う。即ち、プラットフォーム２の動揺５は、プラットフォーム２およびペイロード３の構造を通して像面検出器１１、主鏡１２、副鏡１３に伝達され、各慣性センサ６により検出される。一方、駆動鏡１０に設置された慣性センサ６は対慣性系回転角θm１７を検出する。これらの慣性センサ６の出力は指向軸変動推定部７に取り込まれて、ペイロード３の指向変動推定値である推定変動Δθe１５（添字eは推定値であることを、Δは変動分すなわちAC成分であることを示す）を出力する。
駆動制御装置８の内部では、目標指向角θc１４（ここでは0）と指向軸変動推定部７からの推定変動Δθe１５とを入力として、変動補償制御部１６にて、推定変動Δθe１５をキャンセルするように補償指令を出力し、これによりアクチュエータ９を駆動制御し、駆動鏡１０の方向角を調整する。駆動鏡１０の対慣性系回転角θm１７は慣性センサ６によって検出されて、指向軸変動推定部７にフィードバックされて、空間安定制御ループを構成する。これにより、ペイロード指向軸４の方向は安定化する。
【００２３】
なお、図３では例えば駆動鏡１０に設置された慣性センサ６は対慣性系回転角θm１７を出力するとしているが、もしも慣性センサ６の出力が駆動鏡１０の対慣性系角加速度θ"mならば、指向軸変動推定部７の内部で積分してθm１７に変換されるものとする。また、指向軸変動推定部７はペイロード３の推定変動Δθe１５（角度の次元の量）を出力するとしているが、角速度または角加速度の次元の推定変動Δθ'eまたはΔθ"eを出力してもよく、その場合にはこれと比較される目標指向角１４も角速度または角加速度の次元の量になる。
【００２４】
この実施の形態では、その運動がペイロード３の指向軸方向に影響を及ぼすペイロード３内の光学系の各構成要素（指向軸決定要素）１０〜１３にそれぞれ慣性センサ６を配置し、その出力からペイロード指向軸４の変動を推定して、この推定変動１５をキャンセルするようにアクチュエータ９を駆動する。このように、複数の指向軸決定要素１０〜１３に慣性センサ６を分散配置することにより、ペイロード３と各指向軸決定要素１０〜１３との間の剛性や、アクチュエータ９から慣性センサ６設置部分までのペイロード３や、場合によってはプラットフォーム２の構造をも含む構造剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行える。また、プラットフォーム２やペイロード３に高い機械剛性が要求されないため、プラットフォーム２やペイロード３が格段と軽量化でき、人工衛星など軽量化の要求が厳しいプラットフォーム２にペイロード３を搭載する場合は、特に有効である。
【００２５】
ところで、この実施の形態で示すような、ペイロード３およびプラットフォーム２としての天体望遠鏡搭載衛星では、典型的な指向安定度要求は0.1〜1μrad（マイクロラジアン）、すなわち10万分の1度前後である。これに対して、衛星や望遠鏡構造の共振周波数は、極端に柔らかい太陽電池パドルを除くと、衛星の大小にもよるが大体10Hzから100Hz位に存在する。したがって、衛星全体の制御を行う姿勢制御系では高々0.1Hz（特殊な場合で1Hz)の制御帯域しか持たせることができず、上記の指向安定度要求を姿勢制御系単独で満足させることは困難な場合が多い。このため、望遠鏡３内部に駆動鏡１０を持たせ、空間安定化制御系を別途構成し、小さい駆動鏡１０を動かすことにより構造物の励振を小さく抑えることで、空間安定化制御系の帯域をあげる。
望遠鏡３の空間安定化制御のために従来から用いられていた指向変動を検出する画像センサでは、帯域が通常は30Hz、最大200Hz程度であり、制御帯域は通常センサの帯域の1/10程度であるため、上記のような望遠鏡３の従来の空間安定化制御帯域は20Hz以下であった。これに対して、この実施の形態により、慣性センサ６として広帯域の加速度計やジッタセンサ等を使用した場合、センサの帯域は1kHz〜数kHz程度に広がるため、制御帯域の１桁の向上が可能になる。また、一般に帯域内の外乱に対しては、制御帯域の１桁の向上は外乱抑制性能の１〜２桁の向上につながる。さらに、従来の衛星では空間安定化制御系による能動的な抑制が困難であった20Hz以上の帯域に存在する各種擾乱源による指向変動を抑えることが可能になるため、制御精度が一層向上する。
さらにまた、大型の望遠鏡３であると衛星全体の重量の半分近くを望遠鏡が占める場合もあり得る。衛星では打上重量の制約から特に軽量化の要求が厳しいが、この実施の形態により、機械剛性が例えば1/4程度でも空間安定化制御の高い制御精度が得られるため、望遠鏡３の鏡材を除く構造部分の重量を1/4程度に低減でき著しい軽量化効果が得られる。
【００２６】
実施の形態２．
上記実施の形態１では、ペイロード３の各指向軸決定要素１０〜１３の慣性系１における運動情報を測定する慣性センサ６を、各指向軸決定要素１０〜１３に直接設置したが、それ自体および指向軸決定要素１０〜１３との間の機械剛性が十分高い部材に設置しても良く、検出された運動情報を同様に用いて空間安定化制御が行える。例えば、後述する図４に示すように、像面検出器１１が取り付けられたペイロード架台１９に慣性センサ６ａを設置し、この慣性センサ６ａにより像面検出器１１の慣性系１に対する運動情報を検出しても良い。この場合、ペイロード架台１９は空間安定化制御の帯域に比べて十分に剛であり、像面検出器１１はペイロード架台１９と一体になって動くものとし、これにより像面検出器１１の慣性系１に対する並進・回転変動は、ペイロード架台１９の慣性系１に対する並進・回転変動と等しくなる。
この場合、それ自体および指向軸決定要素１０〜１３との間の機械剛性が十分高い部材に慣性センサ６ａを設置するが、このような条件を満たす部材が存在しない指向軸決定要素については、指向軸決定要素に直接慣性センサ６を設ければよいため、上記実施の形態１に比して機械剛性の要求を増やすものではなく、上記実施の形態１と同様に、剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行えると共に、プラットフォーム２やペイロード３の軽量化が図れる。
【００２７】
実施の形態３．
次に、この発明の実施の形態３を図４に基づいて説明する。
上記実施の形態１では、ペイロード３の各指向軸決定要素１０〜１３の慣性系１における運動情報を測定する慣性センサ６を、各指向軸決定要素１０〜１３に直接設置したが、この実施の形態では、機械剛性が十分高い基準部としてのペイロード架台１９に慣性センサ６ａを設置し、駆動鏡１０には相対センサ１８を設置する。
ここで相対センサ１８は、物体の別の物体に対する相対的な並進運動情報または回転運動情報を検出するセンサの総称であり、具体的には、並進運動情報を検出できる静電容量センサ、渦電流センサ、レーザ測長器、レーザ干渉計、および回転運動情報を検出できるエンコーダ、タコメータ、ポテンショメータ、オートコリメータ等を指す。この場合の相対センサ１８は、一方を駆動鏡１０に、他方（図示せず）をペイロード架台１９に配して、ペイロード架台１９に対する駆動鏡１０の相対的な運動情報を検出する。
ペイロード架台１９には慣性センサ６ａが設置されているため、駆動鏡１０の慣性系１に対する運動情報は、相対センサ１８の検出情報と慣性センサ６ａの検出情報とを組み合わせることで得られる。
また、上記実施の形態２と同様に、像面検出器１１にはセンサを配置せず、ペイロード架台１９に設置された慣性センサ６ａは、像面検出器１１の慣性系１に対する運動情報を検出するセンサとしても用いる。この場合、ペイロード架台１９は空間安定化制御の帯域に比べて十分に剛であり、像面検出器１１および駆動鏡１０の基台はペイロード架台１９と一体になって動くものとする。
【００２８】
この実施の形態では、以下の数式「数８」に示すように、像面検出器１１の慣性系１に対する並進・回転変動（δIM、φIM）は、ペイロード架台１９上に設置された慣性センサ６ａによって検出される、ペイロード架台１９の慣性系１に対する並進・回転変動（δB、φB）に等しい。また、駆動鏡１０が回転自由度だけを持つものとすれば、その対慣性系回転角φMSは、駆動鏡１０の対ペイロード架台相対回転角φMSr（添字rはrelativeの頭文字）とペイロード架台１９の対慣性系回転角φBの和になり、対慣性系並進変動δMSは、ペイロード架台１９の対慣性系並進変動δBに等しい。
【００２９】
【数８】

【００３０】
また図４に示すように、各慣性センサ６、６ａからの検出情報は指向軸変動推定部７に入力されるが、駆動鏡１０に設けられた相対センサ１８の検出情報は駆動制御装置８に入力される。この空間安定化制御の制御動作を図５の機能ブロック図に基づいて以下に説明する。
プラットフォーム２の動揺５は、プラットフォーム２およびペイロード３の構造を通してペイロード架台１９、主鏡１２、副鏡１３に伝達され、各慣性センサ６ａ、６により検出される。これらの慣性センサ６ａ、６の出力は指向軸変動推定部７に取り込まれて、ペイロード３の指向変動推定値である推定変動Δθe１５を駆動制御装置８に出力する。推定変動Δθe１５の計算は、具体的には数式１においてφXMS＝φXB、φYMS＝φYBと置く。一方、相対センサ１８は駆動鏡１０の対ペイロード架台相対回転角φMSr２０を、駆動制御装置８に出力する。駆動制御装置８の内部では、目標指向角θc１４と指向軸変動推定部７からの推定変動Δθe１５とを入力として、変動補償制御部１６にて、推定変動Δθe１５をキャンセルする指令を出力し、さらに該指令と相対センサ１８からの対ペイロード架台相対回転角φMSr２０とにより、図示しない補償器にて補償指令を出力する。これによりアクチュエータ９を駆動制御し、駆動鏡１０の方向角を調整する。
このように、駆動鏡１０の対ペイロード架台相対回転角２０は駆動鏡１０を動かすための局所制御ループを構成するのに用いられる。自動制御論で良く知られているように、このような局所制御ループは系の減衰を増す。これにより、ペイロード指向軸４の方向は安定化する。
【００３１】
この実施の形態では、像面検出器１１にはセンサを配置せず、機械剛性が十分高い基準部としてのペイロード架台１９に慣性センサ６ａを設置し、駆動鏡１０には相対センサ１８を設置する。そして、ペイロード架台１９の慣性センサ６ａにて像面検出器１１における対慣性系運動情報を検出し、相対センサ１８にて、慣性センサ６ａの検出情報を組み合わせて駆動鏡１０の対慣性系運動情報を検出する。このように、各指向軸決定要素１０〜１３に直接慣性センサ６を設置した上記実施の形態１と同様に、各指向軸決定要素１０〜１３のそれぞれの対慣性系運動情報を検出できて空間安定化制御できるため、上記実施の形態１と同様に、剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行えると共に、プラットフォーム２やペイロード３の軽量化が図れる。また相対センサ１８を使用するため、並進変位や並進速度の検出等、慣性センサ６では困難な検出が可能になり、空間安定化制御における設計の自由度が向上する。
また、相対センサ１８からの対ペイロード架台相対回転角φMSr２０を駆動鏡１０を動かすための局所制御ループを構成するのに用い、系の減衰を増すようにしているため、効果的にペイロード指向軸４の方向は安定化される。なお、このような制御は、フィードフォワードで実現するストラップダウン方式の一種と言える。
【００３２】
なお、上記実施の形態３では、図５に示すような空間安定化制御を行うものであったが、図６に示すように、ペイロード架台１９、主鏡１２、副鏡１３に設けられた各慣性センサ６ａ、６の検出情報と、駆動鏡１０に設けられた相対センサ１８からの対ペイロード架台相対回転角φMSr２０とを指向軸変動推定部７に入力して、ペイロード３の推定変動Δθe１５を出力するようにしても良い。図６に示す指向軸変動推定部７の内部では、入力された対ペイロード架台相対回転角φMSr２０は、ペイロード架台１９上の慣性センサ６ａから入力されたペイロード架台１９の並進・回転変動の情報（δB、φB）と合わせて、数式８に基づいて駆動鏡１０の対慣性系並進・回転変動がまず計算され、他の慣性センサ６からの情報と共にペイロード３の推定変動Δθe１５を求めるのに使用される。このとき得られる推定変動Δθe１５は、図５で示す推定変動Δθe１５とは異なるが、上記実施の形態１の図３で示す推定変動Δθe１５と実質同じものであり、変動補償制御部１６にて、推定変動Δθe１５をキャンセルするように補償指令を出力し、これによりアクチュエータ９を駆動制御し、駆動鏡１０の方向角を調整する。駆動鏡１０の対ペイロード架台相対回転角φMSr２０は、指向軸変動推定部７にフィードバックされて、空間安定制御ループを構成する。これにより、ペイロード指向軸４の方向は安定化する。なお、このような制御は、フィードバックで実現するステーブルプラットフォーム方式の一種と言える。
【００３３】
また、この実施の形態では、相対センサ１８の基準部としてペイロード架台１９を用いたが、これに限るものではなく、それ自身が十分剛な要素であればどの部分を使用してもよく、慣性センサ６が設置された他の指向軸決定要素であっても良い。また、相対関係が把握できていれば、複数の基準部を用いても良い。
さらに、主鏡１２と副鏡１３に設けた慣性センサ６についても、これらの全部または一部を、慣性センサ６ａが配置された基準部に対する相対的運動情報を検出する相対センサ１８に置き換えることができる。
また、相対センサ１８は、慣性センサ６ａが設置された基準部に対する相対的な運動情報を直接検出するものでなくても良く、他の相対センサ設置部位に対する相対的な運動情報を検出し、その相対センサの情報を介して基準部との相対的な運動情報を検出しても良い。
【００３４】
実施の形態４．
次に、この発明の実施の形態４を図７に基づいて説明する。
ここでは、航空機、ヘリコプタ、船舶、車両等のプラットフォーム２に搭載して撮影を行う可視または赤外のビデオカメラ等のペイロード３の空間安定化制御について説明する。
図に示すように、ペイロード３は、指向軸決定要素である光学系要素としての駆動鏡１０、像面検出器１１にて構成され、これら光学系要素の慣性系１に対する位置関係によって、ペイロード３の指向軸４の慣性系１に対する方向が決まる。駆動鏡１０は単純な平面鏡で構成されて開口部から導入した光を反射してペイロード３に入射する。また、ここでは、プラットフォーム２（またはペイロード架台１９）と像面検出器１１は剛に結合され、像面検出器１１の慣性系１に対する運動情報は、プラットフォーム２（またはペイロード架台１９）に設けられた慣性センサ６ａにより検出する。駆動鏡１０には直接慣性センサ６が設けられる。ペイロード３とプラットフォーム２との間、また指向軸決定要素１０、１１間の機械剛性は必要ない。
【００３５】
この実施の形態のような簡単な構成のペイロード３では、指向軸決定要素１０、１１の並進変動は指向変動にならない。このため、指向変動Δθと、プラットフォーム２（またはペイロード架台１９）の対慣性系回転角φB、および駆動鏡１０の対慣性系回転角φMSの間には、以下の関係式が成り立つ。なお、ここでは簡単のために図７で示す紙面内の運動に限定している。
【００３６】
【数９】

【００３７】
プラットフォーム２の動揺５はプラットフォーム２（またはペイロード架台１９）の対慣性系回転角φBに等しく、これは像面検出器１１の対慣性系回転角でもある。プラットフォーム２（またはペイロード架台１９）上と駆動鏡１０上とにそれぞれに設置された慣性センサ６ａ、６の出力φB、φMSから、指向軸変動推定部７にて数式９に基づき指向変動Δθを推定する。駆動制御装置８は、推定された指向変動Δθをキャンセルするように、駆動鏡１０の方向角を調整するアクチュエータ９を駆動制御し、これにより指向軸４の方向は安定化される。
この実施の形態においても、複数の指向軸決定要素１０、１１のそれぞれの対慣性系運動情報を検出できて空間安定化制御できるため、上記実施の形態１と同様に、剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行えると共に、プラットフォーム２やペイロード３の軽量化が図れる。
【００３８】
なお、駆動鏡１０上に慣性センサ６だけでなく、駆動状態の把握やリミットチェック等の為に、別途相対センサやリミットスイッチを付加しても良い。
また、駆動鏡１０は、平面鏡ではなく凹面鏡や凸面鏡のような曲面鏡を使用しても良い。
【００３９】
ところで、この実施の形態で示すような、航空機、ヘリコプタ、船舶、車両等に搭載して撮影を行う可視または赤外のビデオカメラ等の空間安定化装置では、主として駆動系を含む機械剛性の制約によって、高々10Hzの制御系帯域を実現するのがが限界であった（典型値は2〜5Hz）。このため、これより高い周波数帯の外乱に対しては、防振台のような受動的な装置を用意して、これと組み合わせて要求性能を実現していた。これに対して、この実施の形態により、慣性センサ６として、DCも含めて数10Hz〜数100Hzの検出帯域を有するサーボ型ジャイロやサーボ型加速度計を用いた場合、制御帯域を数倍（すなわち20〜50Hz程度まで）上げることが可能になる。したがって、制御系を広帯域化した場合のノイズの増加を差し引いても、センサノイズやアクチュエータの分解能の限界近くで稼動する装置でない限り、能動制御部分に対して外乱抑制性能として少なくとも数倍の性能向上が見込める。
【００４０】
実施の形態５．
次に、この発明の実施の形態５を図８に基づいて説明する。
この実施の形態では、望遠鏡やカメラのような光学系機器ではなく、パラボラアンテナを有する電波系のペイロード３ａが空間安定化制御の対象である。図に示すように、慣性系１に対して動揺するプラットフォーム２ａに搭載されたペイロード３ａは、電波系要素としてのパラボラ面で構成されたアンテナの主鏡１２ａ、副鏡と兼ねた駆動鏡１０ａ（１３ａ）、１次放射器２１で構成され、全体として指向性の送信アンテナを構成する。これら電波系要素の慣性系１に対する位置関係によって、ペイロード３ａの指向軸４の慣性系１に対する方向が決まる。このようにペイロード３ａの指向軸方向の決定に寄与する電波系要素１０ａ、１２ａ、２１を上述した光学系要素と同様に以下、指向軸決定要素と呼ぶ。なお、電波系要素とは、反射面を有するアンテナや放射器、受信器等の電波系素子単体で、それ自体剛であるものとする。また、この場合、ペイロード３ａとプラットフォーム２ａとの間、また各指向軸決定要素１０ａ、１２ａ、２１の間の機械剛性は必要ない。
【００４１】
また、この実施の形態では、それ自身十分剛な基準部としてのペイロード架台１９に慣性センサ６ａを設置している以外は、全て相対センサ１８を用いている。ペイロード架台１９の慣性センサ６ａは、各相対センサ１８の基準となり、相対センサ１８の出力に慣性センサ６ａにより計測されたペイロード架台１９の運動情報を加えることで、相対センサ１８が設置されている部位の慣性系１に対する運動情報を知ることができる。また、ペイロード架台１９の慣性センサ６ａは、ペイロード架台１９に取り付けられた１次放射器２１の対慣性系運動情報を検出するセンサとしても用いる。
ペイロード指向軸４の指向変動に寄与する並進変動は、ペイロード架台１９と指向軸決定要素１０ａ、１２ａ間の相対的な変動であるから、ペイロード架台１９の対慣性系並進変動自体は計測する必要がない。このため、ペイロード架台１９上に設置する慣性センサ６は回転変動を検出できるものだけで十分である。なお、各指向軸決定要素１０ａ、１２ａ上に並進変動を観測する慣性センサを設置した場合には、各要素とペイロード架台１９間の相対並進変動を求めるために、ペイロード架台１９側に設置する慣性センサ６ａにも並進変動の測定機能が要求される。
【００４２】
主鏡１２ａに設置された相対センサ１８では、ペイロード架台１９に対する主鏡１２ａの相対的な運動情報を計測する。駆動鏡１０ａの方向角はアクチュエータ９で制御されているため、駆動鏡１０ａの回転変動はアクチュエータ９にて検出できるもので、アクチュエータ９に設置された相対センサ１８とアクチュエータ９の基台が取り付けられたアームに設置された相対センサ１８とにより、それぞれ駆動鏡１０ａのペイロード架台１９に対する相対的な回転変動、並進変動を計測する。
このように配置された各センサ６ａ、１８からの検出情報に基づいて、ペイロード３の指向軸方向の変動を指向軸変動推定部７にて推定する。駆動制御装置８は、推定された指向軸方向の変動をキャンセルするように、駆動鏡１０ａの方向角を調整するアクチュエータ９を駆動制御し、これにより指向軸４の方向は安定化する。
この実施の形態においても、複数の指向軸決定要素１０ａ、１２ａ、２１のそれぞれの対慣性系運動情報を検出できて空間安定化制御できるため、上記実施の形態１と同様に、剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行えると共に、プラットフォーム２ａやペイロード３ａの軽量化が図れる。
【００４３】
なお、この実施の形態は、類似の構成により構成された受信アンテナや送受共用アンテナに対しても同様に適用できる。
【００４４】
実施の形態６．
次に、この発明の実施の形態６を図９に基づいて説明する。
この実施の形態では、上記実施の形態４の図７で示した空間安定化装置の構成に、ペイロード３の指向軸方向を目標指向方向に追尾させる目標追尾機能を持たせる。図９に示すように、目標追尾像面検出器１１の情報を処理して指向目標を検出し、指向軸方向の目標指向方向に対する誤差を検知する指向誤差検出部２２を備え、検出された誤差を駆動制御装置８に入力して、ペイロード３の指向軸方向を目標指向方向に追尾させて空間安定化制御を行う。
指向目標を検出するセンサとしては、画像処理に基づくものや４象元検出器を利用するもの、特殊なマスクやスリットを通して検出するもの等がある。また、像面検出器１１の出力を直接利用するのではなく、光や電波の一部を分岐したり、同じ光路を通る別波長の光や電波を利用して指向目標検出センサを構成しても良い。
【００４５】
指向誤差検出部２２からの誤差を駆動制御装置８に入力して、ペイロード３の指向軸方向を目標指向方向に追尾させて空間安定化制御を行う方法について、図１０に基づいて以下に説明する。
図１０（ａ）に示す制御では、指向誤差検出部２２からの誤差を駆動制御装置８に入力し、駆動制御装置８内では、誤差補償制御部２５にて誤差をキャンセルするように指令を出力し、次いで指向軸変動推定部７からの推定変動を入力して変動補償制御部１６にて該推定変動をキャンセルするような補償指令をアクチュエータ９に出力する。この場合、目標追尾ループ２７は空間安定ループ２６より狭い帯域として、空間安定ループの外側に構成される。応答の早い内部ループで動揺を抑えて空間安定化しながら、外部ループで目標追尾するので、精度の高い目標追尾が行える。
また、図１０（ｂ）に示す別例による制御では、指向誤差検出部２２からの誤差を駆動制御装置８に入力し、駆動制御装置８内では、指向軸変動推定部７から入力された推定変動と、指向誤差検出部２２からの誤差とから、該推定変動と誤差との双方を含む指向軸方向の誤差を誤差演算部２３にて演算し、演算された誤差を、変動・誤差補償制御部１６ａにてキャンセルするように補償指令をアクチュエータ９に出力する。この場合、空間安定ループと目標追尾ループが１つになった空間安定および目標追尾ループ２８を構成し、空間安定化しつつ目標追尾が行える。
【００４６】
この実施の形態では、上記実施の形態４と同様に、剛性に制約されることなく安定で広帯域・高精度な空間安定化制御が行えると共に、プラットフォーム２やペイロード３の軽量化が図れ、また、ペイロード３の指向軸方向を目標指向方向に追尾させる制御が空間安定化制御と併せて行える。
【００４７】
なお、目標追尾像面検出器１１の情報を処理して指向目標を検出し、指向軸方向の目標指向方向に対する誤差を検知する指向誤差検出部２２は、指向目標を直接検出しないで実際の指向方向を検出するものもある。一例として、大型天体望遠鏡で使用されるFine Guidance Sinsor等と呼ばれるセンサは、望遠鏡の画像に投影されている星像とデータベースとして持っているスターカタログを照合して、実際の指向軸がその時点でどちらを向いているかを検出する。このとき、精度は悪くなるが、指向軸回りの誤差も通常同時に検出できる。また、同じまたは類似の原理に基づく恒星センサ（別名スターセンサ）あるいはスターマッパ、スタートラッカ、北極星センサ等のセンサが人工衛星の姿勢検出用のセンサとして製品化されている。即ち、このようなセンサでは、いわば慣性系基準での指向方向の絶対値を検出する。従って、このような指向方向そのものを出力するセンサを使用する場合には、別途外部から指向目標方向を指示して、目標指向方向との差（すなわち指向誤差）を内部で求めることになる。
【００４８】
実施の形態７．
次に、この発明の実施の形態７について説明する。
上記実施の形態１〜６で用いた慣性センサ６は、出力する信号（加速度センサであれば加速度、レートジャイロであれば角速度）にいくらかのバイアスを含む。また、このバイアス値は時間や温度環境などによって変化する。このため、慣性センサ６の出力信号だけを基準にして一定の指向方向を長時間保持し続けることはできず、指向方向は少しずつドリフトしていく。ただし、空間安定化制御の目的は、プラットフォーム２の動揺に伴うある程度高い周波数領域の指向変動を抑えることであるため、空間安定化制御のみについてはドリフトがあっても問題はないが、この実施の形態では、このようなドリフトを抑えるために、姿勢センサを用いる。地上系や船舶、車両、航空機などでは、重力方向を基準にして物体の傾角を測定する傾斜計（クリノメータ）や加速度計、地磁気を基準に物体の姿勢角や方位角を測定する磁気センサや磁気コンパス、地球自転を基準にして方位を測るジャイロコンパス、衛星を基準に姿勢を測る特殊なＧＰＳ受信機などがある。また、人工衛星では、地球や太陽、星等の天体を基準にする地球センサ、太陽センサ、恒星センサ、地球磁場を基準にする磁気センサなどがある。姿勢センサを光学系、電波系要素である指向軸決定要素のどれか、またはこれらの要素との相対関係が判っている基準部分に設置して、姿勢センサ出力と慣性センサ出力とを用いることで、プラットフォーム２の動揺に伴う指向変動と、ドリフトによる指向変動の双方を抑制することができる。
ただし、姿勢センサは指向軸の方向を計測するものではなく、時間ドリフトを抑えるものである。姿勢センサの帯域は通常慣性センサの帯域より狭いため、空間安定が必要な高域側は慣性センサが受け持つ。しかし、もしも安定化したい動揺の周波数が姿勢センサの帯域内であるならば、１つないし複数の慣性センサを姿勢センサで置き換えても良い。
【００４９】
【発明の効果】
この発明に係る空間安定化装置は、慣性空間に対して動揺するプラットフォームに搭載された光学機器あるいは通信アンテナから成るペイロードの指向軸方向を慣性空間に対して安定化制御する装置構成であって、上記ペイロードの構成要素で該ペイロードの指向軸方向の決定に寄与する複数の指向軸構成要素（光学系要素あるいは電波系要素）の慣性空間に対する運動情報をそれぞれ検出する複数のセンサと、上記ペイロードの指向軸方向の変動を推定する指向軸変動推定手段とを備える。上記各センサは、上記指向軸構成要素毎の慣性空間に対する並進および回転の一方あるいは双方の変動情報を上記運動情報として検出する。そして、上記指向軸変動推定手段は、上記指向軸構成要素毎に決定される上記指向軸変動の感度情報を用いて、上記各センサからの該指向軸構成要素毎の上記各変動情報を合成する演算を行い、上記ペイロードの指向軸方向の変動を推定する。このため、ペイロードやプラットフォームの剛性に制約されることなく、安定で広帯域・高精度な空間安定化制御が行える。また、プラットフォームやペイロードに高い機械剛性が要求されないため、プラットフォームやペイロードが格段と軽量化できる。
【図面の簡単な説明】
【図１】 この発明の実施の形態１による空間安定化装置を備えたプラットフォーム及びペイロードを示す構成図である。
【図２】 この発明の実施の形態１による慣性センサの配置例を示す図である。
【図３】 この発明の実施の形態１による空間安定化制御を説明する機能ブロック図である。
【図４】 この発明の実施の形態３による空間安定化装置を備えたプラットフォーム及びペイロードを示す構成図である。
【図５】 この発明の実施の形態３による空間安定化制御を説明する機能ブロック図である。
【図６】 この発明の実施の形態３の別例による空間安定化制御を説明する機能ブロック図である。
【図７】 この発明の実施の形態４による空間安定化装置を備えたプラットフォーム及びペイロードを示す構成図である。
【図８】 この発明の実施の形態５による空間安定化装置を備えたプラットフォーム及びペイロードを示す構成図である。
【図９】 この発明の実施の形態６による空間安定化装置を備えたプラットフォーム及びペイロードを示す構成図である。
【図１０】 この発明の実施の形態６による空間安定化制御を説明する機能ブロック図である。
【符号の説明】
１ 慣性系、２，２ａ プラットフォーム、３，３ａ ペイロード、
４ ペイロード指向軸、５ プラットフォームの動揺、６，６ａ 慣性センサ、
７ 指向軸変動推定部、８ 駆動制御装置、９ アクチュエータ、
１０，１０ａ 指向軸決定要素としての駆動鏡、
１１ 指向軸決定要素としての像面検出器、
１２，１２ａ 指向軸決定要素としての主鏡、
１３，１３ａ 指向軸決定要素としての副鏡、１４ 目標指向角、
１５ 推定変動、１６ 変動補償制御部、１６ａ 誤差・変動補償制御部、
１８ 相対センサ、１９ 基準部としてのペイロード架台、
２１ 指向軸決定要素としての一次放射器、２２ 指向誤差検出部、
２５ 誤差補償制御部。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a space stabilization device that stabilizes and controls a payload of a camera, a communication antenna, a telescope, and the like installed on a platform such as an aircraft, a ship, an artificial satellite, and the like with respect to an inertial space.
[0002]
[Prior art]
A conventional space stabilization device is, for example, a radar oscillation stabilization control device mounted on a hull. A three-axis rate gyro mounted on the hull generates a boat oscillation speed signal, and according to the direction angle of the radar. The direction correction speed signal is calculated to drive the elevation angle and turning angle of the radar (see, for example, Patent Document 1).
In addition, the conventional space stabilizer is a stable platform type space stabilizer. The inertial sensor installed in the payload detects the movement of the payload relative to the inertial space using an inertial sensor such as a gyro and feeds back the information to the controller. Then, the actuator is driven so as to suppress the fluctuation of the payload with respect to the inertial space. On the other hand, in a strap-down type space stabilizer, an inertial sensor such as a gyro is installed on the platform to detect the platform sway relative to the inertial space, and the payload is relative to the platform so as to cancel the platform sway. To stabilize the payload directivity axis (for example, see Non-Patent Document 1).
[0003]
[Patent Document 1]
JP-A-50-61589 (see page 1-2, FIG. 1)
[Non-Patent Document 1]
Norimasa Yoshida, “Study on High Accuracy of Space Stabilizer (1st Report, Comparison of Characteristics between Stable Platform and Strapdown),” Japan Society of Mechanical Engineers, Vol. 65, No. 630, published in February 1999, pp See .485-492
[0004]
[Problems to be solved by the invention]
In the conventional space stabilization device, in the stable platform system, the entire payload is driven to stabilize the directional axis of the payload. Therefore, in the case of a large payload relative to the platform, the payload itself is driven. It was difficult. Moreover, since the inertial sensor detects the fluctuation of the payload and performs feedback control so as to suppress the fluctuation and drives the payload with the actuator, the height of the mechanical rigidity including the payload between the actuator and the inertial sensor is the above feedback control. It relates to the controllability. On the other hand, with the strap-down method, it is possible to achieve space stability by driving only a small drive mirror that changes the directional axis of the payload, for example, without moving the entire payload, but the mechanical rigidity of the payload itself is low, If the mechanical rigidity between the actuator and the platform on which the inertial sensor is installed is low, the directional axis of the payload is correctly controlled even if the actuator is driven to cancel the vibration based on the vibration information from the inertial sensor. It does not mean that
As described above, any of the conventional space stabilization devices requires high mechanical rigidity between the payload itself and the actuator / inertia sensor, and it has been difficult to obtain high control accuracy due to restrictions on the mechanical rigidity. Further, in the staple platform system, the space stabilization control system is easily destabilized due to mechanical rigidity, and the control bandwidth that can be realized is limited, resulting in a limit in control accuracy. Furthermore, since high mechanical rigidity is required for the payload, there is a limit to reducing the weight of the payload.
[0005]
The present invention has been made to solve the above-described problems, and relaxes the demands on the mechanical rigidity of the payload and the platform to reduce the weight of the payload and the platform structure and to stabilize the space. An object is to achieve a high control bandwidth and an improvement in control accuracy in the optimization control.
[0006]
[Means for Solving the Problems]
  A space stabilization device according to the present invention is a device configuration for stabilizing and controlling the directional axis direction of a payload composed of an optical device or a communication antenna mounted on a platform that swings with respect to an inertial space, with respect to the inertial space, The payload components detect motion information with respect to the inertial space of a plurality of directional axis components (optical system elements or radio wave system elements) that contribute to the determination of the directional axis direction of the payload.pluralWith sensor,UpAnd directional axis fluctuation estimation means for estimating fluctuations in the directional axis direction of the payloadThe Each of the sensors detects, as the movement information, fluctuation information of one or both of translation and rotation with respect to the inertial space for each directional axis component. And the said directional axis fluctuation | variation estimation means synthesize | combines each said fluctuation | variation information for every said directional axis component from each said sensor using the sensitivity information of the said directional axis fluctuation | variation determined for every said directional axis | shaft component. An operation is performed to estimate the fluctuation of the payload in the direction of the directional axis.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a platform and a payload provided with a space stabilization device according to Embodiment 1 of the present invention. Here, a payload 3 such as a telescope having a large reflection optical system is mounted on a platform 2 such as an artificial satellite, and the payload directing axis 4 due to the fluctuation 5 of the platform 2 with respect to the inertial space 1 (hereinafter referred to as the inertial system 1). The direction of the directional axis is stabilized and controlled with respect to the inertial system 1 while suppressing the fluctuation.
As shown in the figure, the payload 3 is composed of a primary mirror 12, a secondary mirror 13, a driving mirror 10, and an image plane detector 11 as optical system elements, and depending on the positional relationship of these optical system elements with respect to the inertial system 1, The direction of the directional axis 4 of the payload 3 with respect to the inertial system 1 is determined. The optical system elements 10 to 13 that contribute to the determination of the directional axis direction of the payload 3 are hereinafter referred to as directional axis determining elements. The optical system element is a single optical element that reflects and transmits light, such as a lens and a mirror, and is itself rigid. In this case, the mechanical rigidity between the payload 3 and the platform 2 and between the directivity axis determining elements 10 to 13 is not necessary.
[0008]
Each directional axis determination element 10 to 13 is provided with an inertial sensor 6 for detecting motion information with respect to the inertial space, and based on the detection information from each inertial sensor 6, the variation in the directional axis direction of the payload 3 is changed to the directional axis variation. Estimation is performed by the estimation unit 7. The drive control device 8 drives and controls the actuator 9 that adjusts the direction angle of the drive mirror 10 so as to eliminate the estimated fluctuation in the direction of the directional axis, thereby stabilizing the direction of the directional axis 4.
In this way, the space stabilization device includes the inertial sensor 6, the directional axis fluctuation estimation unit 7, the actuator 9 that changes the directional axis direction, and the drive control device 8 provided in each of the directional axis determination elements 10 to 13 of the payload 3. Thus, the directional axis direction of the payload 3 is controlled to be stabilized with respect to the inertial system 1.
[0009]
Hereinafter, details of the space stabilization control will be described. First, processing in the pointing axis fluctuation estimation unit 7 that estimates the fluctuation in the pointing axis direction will be described.
In the optical system payload 3 having the configuration as shown in FIG. 1, if the directivity axis direction is Z and the optical axis bending direction (perpendicular to the Z axis) by the drive mirror 10 is Y, the directivity variation ΔθX around the X axis and around the Y axis. , ΔθY are translational and rotational variations (δXi, δYi and φXi, φYi with respect to the inertial system 1 of the primary mirror 12, the secondary mirror 13, the driving mirror 10, and the image plane detector 11 which are directional axis determining elements; M1, M2, MS, and IM represent the primary mirror 12, the secondary mirror 13, the driving mirror 10, and the image plane detector 10, respectively).
[0010]
[Expression 1]

[0011]
Here, Xi and Yi are local coordinates perpendicular to the optical principal axes of the respective directional axis determining elements 10 to 13. For example, the XIM axis of the image plane detector 11 is an axis parallel to the X axis of the payload 3, and the YIM axis is This is an axis parallel to the Z-axis direction of the payload 3. 1, the Xi axis and Yi axis of the primary mirror 12 and the secondary mirror 13 are both parallel to the X axis and Y axis of the payload 3, and the Xi axis of the drive mirror 10 is parallel to the X axis of the payload 3. The Yi axis is an axis obtained by tilting the Y axis of the payload 3 by 45 ° clockwise around the X axis. Also, aXXi, aYYi, bXYi, bYXi in the equation are coefficients determined by the optical system, and directivity fluctuation around the X axis or Y axis with respect to rotational fluctuations φXi, φYi, translational fluctuations δYi, δXi of the directional axis determining element i, respectively. The sensitivity of ΔθX and ΔθY is shown.
However, linear approximation is performed on the assumption that the pointing error and the translation / rotation fluctuation are minute amounts. Further, the rotation of the payload directing axis 4 around the Z axis corresponds to the image rotation, and depending on the space stabilization device, spatial stability with respect to the image rotation may be required. To do.
[0012]
For a more general optical system configuration, translational / rotational variations (δXi, δYi • φXi, φYi) and directivity variations of each element (directional axis determining element) constituting the optical system with respect to the inertial system 1 The relationship with (ΔθX, ΔθY) is expressed by the following relational expression. Also in this case, linear approximation is performed for a minute amount.
[0013]
[Expression 2]

[0014]
In addition, when space stability with respect to image rotation is required, the following relational expression is obtained including fluctuations about the Z axis of the payload directing axis 4 corresponding to the image rotation.
[Equation 3]

[0015]
Next, a specific method for measuring the translational and rotational fluctuations (δi, φi) of the directional axis determining elements 10 to 13 in the inertial system 1 from the outputs of the inertial sensors 6 installed on the directional axis determining elements 10 to 13 will be described. explain. Here, the inertial sensor 6 is a general term for sensors that detect translational motion information (position, velocity, acceleration, etc.) or rotational motion information (angle, angular velocity, angular acceleration, etc.) of the object relative to the inertial system 1. Specifically, it refers to an accelerometer that detects translational motion information, a gyro that detects rotational motion information, a jitter sensor (a broadband special sensor that detects angles, angular velocities, etc.), and the like.
FIGS. 2A and 2B show two examples of arrangement of the inertial sensor 6 on the directivity axis determination elements 10 to 13 in a plan view and a side view. FIG. 2A shows an example of being arranged on the back side of the reflecting surface of the directional axis determining element, and FIG. 2B shows an example of being arranged on the side surface of the directional axis determining element. In any arrangement, a uniaxial accelerometer is used as the inertial sensor 6. In the figure, the arrow indicates the direction of the sensitivity axis of the sensor, and the black circle indicates that the sensor has sensitivity in the forward direction perpendicular to the paper surface. Also, A (Axial acronym) has sensitivity in the axial direction (Z-axis direction), R (Radial acronym) has sensitivity in the radial direction, and T (Tangential acronym) has sensitivity in the tangential direction. It is an arranged sensor.
[0016]
From the output of these accelerometers (inertial sensor 6) (the sensor identification name is appended to a indicating acceleration as aA1, aR2, etc.), the translational acceleration δ " Xi, δ ″ Yi and rotational angular acceleration φ ″ Xi, φ ″ Yi can be obtained by the following mathematical expressions. However, 'represents the first-order time derivative, and' represents the second-order time derivative. For simplicity, the suffix i is omitted, and the reference plane of each directional axis determining element (for example, the reflecting surface of a plane mirror) The distance in the Z direction between the sensor installation point is ignored because it is smaller than r.
[0017]
In the arrangement shown in FIG.
[Expression 4]

In the arrangement shown in FIG.
[Equation 5]

[0018]
In this case, an example in which a uniaxial accelerometer is used as the inertial sensor 6 has been shown. However, as described above, various gyros and jitter sensors that can directly measure angular velocity and angular variation may be used. Φ'i and φi are measured instead of a few suitable inertial sensors that can detect the velocity δ'i and displacement δi with respect to the inertial system, but can be detected by the method using a relative sensor described later. is there.
In the case of spatial stability, the purpose is to suppress the directivity fluctuation accompanying fluctuations, so it is important to know the fluctuation component of δi and φi, that is, the AC component, and a constant value, that is, a DC component is not necessarily required. Therefore, if the translational acceleration δ "i (or velocity δ'i) and the rotational angular acceleration φ" i (or angular velocity φ'i) of each directional axis determining element i are obtained, integration is always possible. It is easy to obtain δi and φi by time integration.
Further, without integrating the translational acceleration δ "i (or velocity δ'i) or the rotational angular acceleration φ" i (or angular velocity φ'i), the translational / rotational variation (δi, · φi) and the directivity variation (Δθ The following formulas obtained by differentiating the both sides of the above formulas “Equation 2” and “Equation 3” with respect to the first or second order time may be used.
[0019]
[Formula 6]

[Expression 7]

[0020]
In this case, the first-order or second-order time differential value Δθ ′ or Δθ ″ of the directivity variation Δθ is obtained by the mathematical formulas “Equation 6” and “Equation 7”, and this is used as it is, or Δθ ′ obtained by integrating the first or second order. In the form of Δθ, it is used for spatial stabilization control.This is more effective from the viewpoint of constructing the control system.In addition, a plurality of different types of sensors are combined (for example, a gyro and an accelerometer, a geomagnetic sensor). A combination), a wide band and a DC component can also be output.
[0021]
As described in detail above, the translational and rotational fluctuations (δi, φi) in the inertial system 1 of each directional axis determining element 10-13 are measured by the inertial sensor 6 installed in each directional axis determining element 10-13. Thus, the directivity variation Δθ of the payload 3 can be calculated. Through such calculation processing, the pointing axis fluctuation estimation unit 7 shown in FIG. 1 estimates the pointing fluctuation Δθ of the payload directing axis 4 using the detection information of each inertial sensor 6 as an input.
[0022]
FIG. 3 is a functional block diagram showing the control operation of the space stabilization control.
In accordance with the sway 5 of the platform 2, each of the directional axis determining elements 10 to 13 constituting the payload 3 generally undergoes different translational and rotational fluctuations unless it is a rigid integral structure. That is, the fluctuation 5 of the platform 2 is transmitted to the image plane detector 11, the primary mirror 12, and the secondary mirror 13 through the structure of the platform 2 and the payload 3, and is detected by each inertial sensor 6. On the other hand, the inertial sensor 6 installed in the drive mirror 10 detects the rotation angle θm17 against the inertial system. The outputs of these inertial sensors 6 are taken into the directional axis fluctuation estimation unit 7 and estimated fluctuation Δθe15 (the subscript e is the estimated value, where Δ is the fluctuation, that is, the AC component), which is the directional fluctuation estimated value of the payload 3. Output).
Inside the drive control device 8, the target compensation angle θc14 (here, 0) and the estimated variation Δθe15 from the pointing axis variation estimation unit 7 are input, and the variation compensation control unit 16 cancels the estimated variation Δθe15. A compensation command is output, whereby the actuator 9 is driven and controlled, and the direction angle of the driving mirror 10 is adjusted. The rotation angle θm17 with respect to the inertial system of the drive mirror 10 is detected by the inertial sensor 6 and fed back to the directional axis fluctuation estimation unit 7 to constitute a space stability control loop. As a result, the direction of the payload directing axis 4 is stabilized.
[0023]
In FIG. 3, for example, the inertial sensor 6 installed in the drive mirror 10 outputs the inertial system rotation angle θm17. However, if the output of the inertial sensor 6 is the inertial system angular acceleration θ ″ m of the drive mirror 10, For example, it is assumed that it is integrated and converted into θm 17 in the directional axis fluctuation estimation unit 7. The directional axis fluctuation estimation unit 7 outputs the estimated fluctuation Δθe15 (the amount of the angle dimension) of the payload 3. However, the estimated variation Δθ′e or Δθ ″ e of the dimension of the angular velocity or angular acceleration may be output, and in this case, the target directivity angle 14 to be compared with this is also an amount of the dimension of the angular velocity or angular acceleration.
[0024]
In this embodiment, the inertial sensor 6 is arranged in each component (directional axis determining element) 10 to 13 of the optical system in the payload 3 whose movement affects the direction of the directional axis of the payload 3, and from the output thereof The fluctuation of the payload directing axis 4 is estimated, and the actuator 9 is driven so as to cancel the estimated fluctuation 15. In this manner, by distributing the inertial sensors 6 to the plurality of directional axis determining elements 10 to 13, the rigidity between the payload 3 and the directional axis determining elements 10 to 13, and the actuator 9 to the inertial sensor 6 installation part. Stable, broadband, and high-accuracy spatial stabilization control can be performed without being limited by the structural rigidity including the payload 3 or the structure of the platform 2 in some cases. In addition, since high mechanical rigidity is not required for the platform 2 and the payload 3, the platform 2 and the payload 3 can be remarkably reduced in weight, and it is particularly effective when the payload 3 is mounted on the platform 2 that requires severe weight reduction such as an artificial satellite. It is.
[0025]
By the way, in the satellite equipped with the astronomical telescope as the payload 3 and the platform 2 as shown in this embodiment, a typical pointing stability requirement is 0.1 to 1 μrad (microradians), that is, about 1 / 100,000 degree. On the other hand, the resonance frequency of the satellite or telescope structure is approximately 10 Hz to 100 Hz, depending on the size of the satellite, except for extremely soft solar battery paddles. Therefore, the attitude control system that controls the entire satellite can only have a control bandwidth of at most 0.1 Hz (1 Hz in special cases), and it is difficult to satisfy the above directional stability requirement alone. There are many cases. For this reason, the driving mirror 10 is provided inside the telescope 3, a space stabilization control system is separately configured, and the excitation of the structure is suppressed by moving the small driving mirror 10, thereby reducing the bandwidth of the space stabilization control system. I'll give you.
In the image sensor that detects the directional fluctuation that has been used for the space stabilization control of the telescope 3 in the past, the band is usually about 30 Hz and the maximum is about 200 Hz, and the control band is about 1/10 of the band of the normal sensor. Therefore, the conventional spatial stabilization control band of the telescope 3 as described above is 20 Hz or less. On the other hand, according to this embodiment, when a broadband accelerometer, a jitter sensor, or the like is used as the inertial sensor 6, the sensor band is expanded to about 1 kHz to several kHz, so that the control band can be improved by one digit. become. In general, for disturbances in the band, an improvement of one digit in the control band leads to an improvement of one to two digits in the disturbance suppression performance. Furthermore, since it is possible to suppress pointing fluctuations caused by various disturbance sources existing in a band of 20 Hz or higher, which is difficult to actively suppress by a space stabilization control system in a conventional satellite, control accuracy is further improved.
Furthermore, in the case of the large telescope 3, the telescope may occupy nearly half of the weight of the entire satellite. With satellites, the demand for weight reduction is particularly severe due to launch weight limitations, but this embodiment provides high control accuracy for space stabilization control even when the mechanical rigidity is about 1/4, for example. The weight of the structure part to be removed can be reduced to about 1/4, and a remarkable lightening effect can be obtained.
[0026]
Embodiment 2. FIG.
In the first embodiment, the inertial sensor 6 that measures the motion information in the inertial system 1 of each directional axis determination element 10-13 of the payload 3 is directly installed in each directional axis determination element 10-13. It may be installed on a member having sufficiently high mechanical rigidity with respect to the directional axis determining elements 10 to 13, and space stabilization control can be performed using the detected motion information in the same manner. For example, as shown in FIG. 4 to be described later, an inertial sensor 6a is installed on a payload base 19 to which the image plane detector 11 is attached, and motion information of the image plane detector 11 with respect to the inertial system 1 is detected by the inertial sensor 6a. You may do it. In this case, the payload base 19 is sufficiently rigid as compared to the space stabilization control band, and the image plane detector 11 moves integrally with the payload base 19, thereby the inertial system of the image plane detector 11. The translation / rotation fluctuation with respect to 1 is equal to the translation / rotation fluctuation with respect to the inertial system 1 of the payload base 19.
In this case, the inertial sensor 6a is installed on a member having a sufficiently high mechanical rigidity between itself and the directional axis determining elements 10 to 13, but the directional axis determining element having no member satisfying such a condition has a directivity. Since it is only necessary to provide the inertial sensor 6 directly on the axis determining element, the mechanical rigidity requirement is not increased as compared with the first embodiment, and the rigidity is not limited as in the first embodiment. In addition, stable, wide-band, and high-precision space stabilization control can be performed, and the platform 2 and payload 3 can be reduced in weight.
[0027]
Embodiment 3 FIG.
Next, a third embodiment of the present invention will be described with reference to FIG.
In the first embodiment, the inertial sensor 6 that measures the motion information in the inertial system 1 of each directional axis determination element 10-13 of the payload 3 is directly installed in each directional axis determination element 10-13. In the embodiment, the inertial sensor 6 a is installed on the payload base 19 as a reference portion having sufficiently high mechanical rigidity, and the relative sensor 18 is installed on the drive mirror 10.
Here, the relative sensor 18 is a general term for sensors that detect translational motion information or rotational motion information relative to another object. Specifically, the relative sensor 18 is a capacitive sensor that can detect translational motion information, an eddy current, and the like. It refers to sensors, laser measuring instruments, laser interferometers, encoders that can detect rotational motion information, tachometers, potentiometers, autocollimators, and the like. In this case, one of the relative sensors 18 is disposed on the drive mirror 10 and the other (not shown) is disposed on the payload base 19 to detect relative motion information of the drive mirror 10 with respect to the payload base 19.
Since the inertial sensor 6a is installed on the payload base 19, motion information for the inertial system 1 of the driving mirror 10 is obtained by combining detection information of the relative sensor 18 and detection information of the inertial sensor 6a.
Similarly to the second embodiment, no sensor is arranged on the image plane detector 11, and the inertial sensor 6 a installed on the payload base 19 detects motion information of the image plane detector 11 with respect to the inertial system 1. Also used as a sensor. In this case, it is assumed that the payload base 19 is sufficiently rigid compared to the space stabilization control band, and the bases of the image plane detector 11 and the drive mirror 10 move together with the payload base 19.
[0028]
In this embodiment, the translational / rotational fluctuations (δIM, φIM) of the image plane detector 11 with respect to the inertial system 1 are represented by the following mathematical expression “Equation 8”, and the inertial sensor 6 a installed on the payload base 19. Is equal to the translational / rotational fluctuation (δB, φB) of the payload gantry 19 with respect to the inertial system 1. Further, if the driving mirror 10 has only the degree of freedom of rotation, the rotation angle φMS with respect to the inertial system corresponds to the relative rotation angle φMSr of the driving mirror 10 with respect to the payload frame (subscript r is an acronym for relative) and the payload frame 19. The inertial system translational fluctuation δMS is equal to the inertial system translational fluctuation δB of the payload gantry 19.
[0029]
[Equation 8]

[0030]
As shown in FIG. 4, detection information from the inertial sensors 6 and 6 a is input to the directivity axis fluctuation estimation unit 7, but detection information of the relative sensor 18 provided in the drive mirror 10 is input to the drive control device 8. Entered. The control operation of this space stabilization control will be described below based on the functional block diagram of FIG.
The sway 5 of the platform 2 is transmitted to the payload base 19, the primary mirror 12, and the secondary mirror 13 through the structure of the platform 2 and the payload 3, and is detected by the inertial sensors 6 a and 6. Outputs of these inertial sensors 6 a and 6 are taken into the directional axis fluctuation estimation unit 7, and an estimated fluctuation Δθe 15 that is a directional fluctuation estimated value of the payload 3 is output to the drive control device 8. Specifically, the estimated fluctuation Δθe15 is calculated as φXMS = φXB and φYMS = φYB in Equation 1. On the other hand, the relative sensor 18 outputs the relative rotation angle φMSr20 of the drive mirror 10 to the payload base to the drive control device 8. Inside the drive control device 8, the target directivity angle θc 14 and the estimated variation Δθe15 from the directional axis variation estimation unit 7 are input, and the variation compensation control unit 16 outputs a command to cancel the estimated variation Δθe15. A compensation command is output by a compensator (not shown) according to the command and the relative rotation angle φMSr20 with respect to the payload base from the relative sensor 18. Thereby, the actuator 9 is driven and controlled, and the direction angle of the driving mirror 10 is adjusted.
Thus, the relative rotation angle 20 of the drive mirror 10 with respect to the payload base is used to form a local control loop for moving the drive mirror 10. As is well known in automatic control theory, such a local control loop increases the damping of the system. As a result, the direction of the payload directing axis 4 is stabilized.
[0031]
In this embodiment, no sensor is disposed on the image plane detector 11, the inertial sensor 6 a is disposed on the payload base 19 as a reference portion having sufficiently high mechanical rigidity, and the relative sensor 18 is disposed on the drive mirror 10. . Then, the inertial sensor 6a of the payload base 19 detects the inertial motion information in the image plane detector 11, and the relative sensor 18 combines the detection information of the inertial sensor 6a to detect the inertial motion information of the drive mirror 10. Is detected. In this way, as in the first embodiment in which the inertial sensor 6 is directly installed on each directional axis determining element 10-13, the motion information of each directional axis determining element 10-13 can be detected and the space can be detected. Since the stabilization control can be performed, the platform 2 and the payload 3 can be reduced in weight while being able to perform a stable, wideband and high-accuracy space stabilization control without being restricted by rigidity, as in the first embodiment. In addition, since the relative sensor 18 is used, detection that is difficult with the inertial sensor 6 such as detection of translational displacement and translational velocity can be performed, and the degree of design freedom in space stabilization control is improved.
Further, since the relative rotation angle φMSr20 with respect to the payload base from the relative sensor 18 is used to construct a local control loop for moving the driving mirror 10, the attenuation of the system is increased. The direction of is stabilized. Such control can be said to be a kind of strap-down method realized by feedforward.
[0032]
In the third embodiment, the space stabilization control as shown in FIG. 5 is performed. However, as shown in FIG. 6, each of the payload mount 19, the primary mirror 12, and the secondary mirror 13 provided. The detection information of the inertial sensors 6a and 6 and the relative rotation angle φMSr20 with respect to the payload base from the relative sensor 18 provided in the drive mirror 10 are input to the pointing axis fluctuation estimation unit 7 and the estimated fluctuation Δθe15 of the payload 3 is output. You may make it do. In the pointing axis fluctuation estimation unit 7 shown in FIG. 6, the input relative rotation angle φMSr20 with respect to the payload base is the information on the translation / rotation fluctuation (δB) of the payload base 19 input from the inertial sensor 6a on the payload base 19. , ΦB), the translational / rotational variation of the driving mirror 10 with respect to the inertial system is first calculated based on the equation 8, and is used to obtain the estimated variation Δθe15 of the payload 3 together with information from the other inertial sensors 6. . The estimated fluctuation Δθe15 obtained at this time is different from the estimated fluctuation Δθe15 shown in FIG. 5, but is substantially the same as the estimated fluctuation Δθe15 shown in FIG. 3 of the first embodiment, and is estimated by the fluctuation compensation control unit 16. A compensation command is output so as to cancel the fluctuation Δθe15, thereby driving the actuator 9 and controlling the direction angle of the driving mirror 10. The relative rotation angle φMSr20 of the drive mirror 10 with respect to the payload base is fed back to the directivity axis fluctuation estimation unit 7 to constitute a space stability control loop. As a result, the direction of the payload directing axis 4 is stabilized. Such control can be said to be a kind of stable platform method realized by feedback.
[0033]
In this embodiment, the payload base 19 is used as the reference portion of the relative sensor 18, but the present invention is not limited to this, and any portion may be used as long as it is a sufficiently rigid element. Another directional axis determining element in which the sensor 6 is installed may be used. Further, a plurality of reference parts may be used as long as the relative relationship can be grasped.
Further, with respect to the inertial sensors 6 provided in the primary mirror 12 and the secondary mirror 13, all or a part of them may be replaced with a relative sensor 18 that detects relative motion information with respect to a reference portion on which the inertial sensor 6 a is arranged. it can.
Further, the relative sensor 18 may not directly detect the relative motion information with respect to the reference portion where the inertial sensor 6a is installed, but detects the relative motion information with respect to other relative sensor installation sites. You may detect the relative motion information with the reference | standard part via the information of a relative sensor.
[0034]
Embodiment 4 FIG.
Next, a fourth embodiment of the present invention will be described with reference to FIG.
Here, the spatial stabilization control of the payload 3 such as a visible or infrared video camera that is mounted on the platform 2 such as an aircraft, helicopter, ship, or vehicle and performs imaging will be described.
As shown in the figure, the payload 3 is composed of a driving mirror 10 and an image plane detector 11 as optical system elements that are directional axis determining elements, and the payload 3 is determined by the positional relationship of these optical system elements with respect to the inertial system 1. The direction of the directivity axis 4 with respect to the inertial system 1 is determined. The drive mirror 10 is configured by a simple plane mirror, reflects the light introduced from the opening, and enters the payload 3. Further, here, the platform 2 (or the payload pedestal 19) and the image plane detector 11 are rigidly coupled, and motion information for the inertial system 1 of the image plane detector 11 is provided in the platform 2 (or the payload pedestal 19). Detected by the inertial sensor 6a. The drive mirror 10 is directly provided with the inertial sensor 6. There is no need for mechanical stiffness between the payload 3 and the platform 2 and between the pointing axis determining elements 10,11.
[0035]
In the payload 3 having a simple configuration as in this embodiment, the translational fluctuations of the directivity axis determining elements 10 and 11 do not become directivity fluctuations. Therefore, the following relational expression is established between the directivity variation Δθ, the anti-inertia system rotation angle φB of the platform 2 (or the payload base 19), and the anti-inertia system rotation angle φMS of the drive mirror 10. Here, for the sake of simplicity, the movement is limited to the in-plane movement shown in FIG.
[0036]
[Equation 9]

[0037]
The sway 5 of the platform 2 is equal to the anti-inertia rotation angle φB of the platform 2 (or the payload mount 19), which is also the anti-inertia rotation angle of the image plane detector 11. From the outputs φB and φMS of the inertial sensors 6a and 6 installed on the platform 2 (or the payload base 19) and the driving mirror 10, respectively, the directivity variation estimation unit 7 estimates the directivity variation Δθ based on Expression 9. To do. The drive control device 8 drives and controls the actuator 9 that adjusts the direction angle of the drive mirror 10 so as to cancel the estimated directivity fluctuation Δθ, thereby stabilizing the direction of the directional axis 4.
Also in this embodiment, since it is possible to detect the motion information of each of the plurality of directional axis determining elements 10 and 11 with respect to the inertial system and to perform space stabilization control, it is limited to rigidity as in the first embodiment. In addition, stable, wide-band, and high-precision space stabilization control can be performed, and the weight of the platform 2 and the payload 3 can be reduced.
[0038]
Note that not only the inertial sensor 6 but also a relative sensor or a limit switch may be added on the driving mirror 10 for grasping the driving state, limit checking, or the like.
The driving mirror 10 may be a curved mirror such as a concave mirror or a convex mirror instead of a plane mirror.
[0039]
By the way, in a space stabilization device such as a visible or infrared video camera that is mounted on an aircraft, helicopter, ship, vehicle, or the like as shown in this embodiment, a mechanical rigidity constraint mainly including a drive system is limited. Therefore, it was the limit to realize a control system bandwidth of at most 10 Hz (typical value is 2 to 5 Hz). For this reason, for a disturbance in a higher frequency band, a passive device such as a vibration isolator is prepared and combined with this to realize the required performance. On the other hand, according to this embodiment, when a servo gyro or a servo accelerometer having a detection band of several tens Hz to several hundred Hz including DC is used as the inertial sensor 6, the control band is multiplied several times (that is, It is possible to increase it to 20-50Hz). Therefore, even if the increase in noise when the control system is widened is subtracted, the performance of the active control part is improved several times as much as the disturbance control performance unless the device operates near the limit of sensor noise and actuator resolution. Can be expected.
[0040]
Embodiment 5. FIG.
Next, a fifth embodiment of the present invention will be described with reference to FIG.
In this embodiment, not the optical system equipment such as a telescope or a camera, but a radio wave system payload 3a having a parabolic antenna is the object of space stabilization control. As shown in the figure, a payload 3a mounted on a platform 2a that swings with respect to the inertial system 1 includes an antenna primary mirror 12a composed of a parabolic surface as a radio wave system element, and a driving mirror 10a (also a secondary mirror). 13a) It is composed of the primary radiator 21 and constitutes a directional transmission antenna as a whole. The direction of the directional axis 4 of the payload 3a relative to the inertial system 1 is determined by the positional relationship of these radio wave elements with respect to the inertial system 1. The radio wave elements 10a, 12a, and 21 that contribute to the determination of the directional axis direction of the payload 3a are hereinafter referred to as directional axis determining elements as in the optical system element described above. The radio wave element is a radio wave element such as an antenna, a radiator, or a receiver having a reflecting surface, and is itself rigid. In this case, the mechanical rigidity between the payload 3a and the platform 2a and between the directivity axis determining elements 10a, 12a, and 21 is not necessary.
[0041]
Further, in this embodiment, all the relative sensors 18 are used except that the inertial sensor 6a is installed on the payload base 19 as a sufficiently rigid reference portion. The inertial sensor 6a of the payload pedestal 19 serves as a reference for each relative sensor 18, and a part where the relative sensor 18 is installed by adding movement information of the payload pedestal 19 measured by the inertial sensor 6a to the output of the relative sensor 18. Motion information for the inertial system 1 can be obtained. Further, the inertial sensor 6 a of the payload gantry 19 is also used as a sensor for detecting the inertial motion information of the primary radiator 21 attached to the payload gantry 19.
Since the translational variation that contributes to the directional variation of the payload directional shaft 4 is a relative variation between the payload gantry 19 and the directional axis determining elements 10a and 12a, it is necessary to measure the translational variation of the payload gantry 19 with respect to the inertia system itself. Absent. For this reason, it is sufficient for the inertial sensor 6 installed on the payload base 19 to be capable of detecting rotational fluctuations. In addition, when an inertial sensor for observing translational fluctuations is installed on each directional axis determining element 10a, 12a, inertia to be installed on the payload base 19 side in order to obtain a relative translational fluctuation between each element and the payload base 19 The sensor 6a is also required to have a translation variation measuring function.
[0042]
The relative sensor 18 installed on the primary mirror 12a measures relative motion information of the primary mirror 12a with respect to the payload base 19. Since the direction angle of the drive mirror 10a is controlled by the actuator 9, the rotational fluctuation of the drive mirror 10a can be detected by the actuator 9, and the relative sensor 18 installed on the actuator 9 and the base of the actuator 9 are attached. Relative fluctuations and translational fluctuations of the drive mirror 10a relative to the payload base 19 are measured by the relative sensor 18 installed on the arm.
Based on the detection information from the sensors 6 a and 18 arranged in this manner, the variation in the directional axis direction of the payload 3 is estimated by the directional axis variation estimation unit 7. The drive control device 8 drives and controls the actuator 9 that adjusts the direction angle of the drive mirror 10a so as to cancel the estimated fluctuation in the direction of the directional axis, thereby stabilizing the direction of the directional axis 4.
Also in this embodiment, since it is possible to detect the motion information of each of the plurality of directional axis determining elements 10a, 12a, and 21 and to control the space stabilization, similarly to the first embodiment, the rigidity is limited. In addition, stable, wideband and high-accuracy spatial stabilization control can be performed, and the platform 2a and payload 3a can be reduced in weight.
[0043]
Note that this embodiment can be similarly applied to a reception antenna or a transmission / reception shared antenna configured with a similar configuration.
[0044]
Embodiment 6 FIG.
Next, a sixth embodiment of the present invention will be described with reference to FIG.
In this embodiment, the configuration of the space stabilization device shown in FIG. 7 of the fourth embodiment is provided with a target tracking function for tracking the directional axis direction of the payload 3 in the target directional direction. As shown in FIG. 9, a pointing error detection unit 22 that processes information of the target tracking image plane detector 11 to detect a pointing target and detects an error of the pointing axis direction with respect to the target pointing direction is provided. Is input to the drive control device 8 to track the directional axis direction of the payload 3 in the target directional direction, and space stabilization control is performed.
Sensors that detect the pointing target include those based on image processing, those that use a four-element detector, and those that detect through a special mask or slit. Further, instead of directly using the output of the image plane detector 11, a pointing target detection sensor is configured by branching a part of light or radio waves or using light or radio waves of different wavelengths passing through the same optical path. Also good.
[0045]
A method for performing space stabilization control by inputting an error from the pointing error detection unit 22 to the drive control device 8 and tracking the pointing axis direction of the payload 3 in the target pointing direction will be described below with reference to FIG. .
In the control shown in FIG. 10A, an error from the pointing error detection unit 22 is input to the drive control device 8, and a command is issued within the drive control device 8 to cancel the error by the error compensation control unit 25. Then, the estimated variation from the directional axis variation estimation unit 7 is input, and a compensation command for canceling the estimated variation is output to the actuator 9 by the variation compensation control unit 16. In this case, the target tracking loop 27 is configured outside the space stable loop as a band narrower than the space stable loop 26. The target tracking is performed in the outer loop while stabilizing the space by suppressing the fluctuation in the inner loop with quick response, so that the target tracking with high accuracy can be performed.
In the control according to another example shown in FIG. 10B, the error from the pointing error detection unit 22 is input to the drive control device 8, and the estimation input from the pointing axis variation estimation unit 7 is performed in the drive control device 8. Based on the fluctuation and the error from the pointing error detector 22, an error in the pointing axis direction including both the estimated fluctuation and the error is calculated by the error calculator 23, and the calculated error is controlled by the fluctuation / error compensation control. A compensation command is output to the actuator 9 so as to be canceled by the unit 16a. In this case, a space stability and target tracking loop 28 in which the space stabilization loop and the target tracking loop are combined to form a target tracking can be performed while stabilizing the space.
[0046]
In this embodiment, as in the fourth embodiment, it is possible to perform stable, wideband and high-accuracy spatial stabilization control without being restricted by rigidity, and to reduce the weight of the platform 2 and the payload 3, Control for tracking the directional axis direction of the payload 3 in the target directional direction can be performed together with the space stabilization control.
[0047]
Note that the pointing error detection unit 22 that processes the information of the target tracking image plane detector 11 to detect the pointing target and detects an error of the pointing axis direction with respect to the target pointing direction does not directly detect the pointing target, but does not detect the pointing target. Some detect the direction. As an example, a sensor called Fine Guidance Sinsor used in a large astronomical telescope collates the star image projected on the telescope image with the star catalog held as a database, and the actual pointing axis is Detect which one you are facing. At this time, although accuracy is deteriorated, an error around the pointing axis can usually be detected simultaneously. Further, a star sensor (also known as a star sensor) or a star mapper, a star tracker, an arctic star sensor or the like based on the same or similar principle has been commercialized as a sensor for detecting the attitude of an artificial satellite. That is, such a sensor detects the absolute value of the pointing direction based on the inertial system reference. Therefore, when using such a sensor that outputs the directivity direction itself, a directivity target direction is separately designated from the outside, and a difference from the target directivity direction (that is, directivity error) is obtained internally.
[0048]
Embodiment 7 FIG.
Next, a seventh embodiment of the present invention will be described.
The inertial sensor 6 used in the first to sixth embodiments includes some bias in the output signal (acceleration if acceleration sensor, angular velocity if rate gyro). Further, this bias value changes depending on time, temperature environment, and the like. For this reason, it is impossible to keep a constant directivity for a long time with reference to only the output signal of the inertial sensor 6, and the directivity drifts little by little. However, since the purpose of the space stabilization control is to suppress the directional fluctuation in the frequency region that is somewhat high due to the shaking of the platform 2, there is no problem even if there is a drift in the space stabilization control alone. In the embodiment, an attitude sensor is used to suppress such drift. In terrestrial systems, ships, vehicles, airplanes, etc., tilt sensors (clinometers) and accelerometers that measure the tilt angle of an object with respect to the direction of gravity, magnetic sensors and magnets that measure the posture angle and azimuth of an object with reference to geomagnetism There are compass, gyrocompass that measures azimuth based on earth rotation, and special GPS receiver that measures attitude based on satellite. Artificial satellites include earth sensors based on celestial bodies such as the earth, the sun, and stars, sun sensors, star sensors, and magnetic sensors based on the earth's magnetic field. By installing the attitude sensor on one of the directional axis determination elements that are optical system and radio wave system elements, or on the reference part where the relative relationship with these elements is known, and using the attitude sensor output and inertial sensor output In addition, it is possible to suppress both the directional fluctuation caused by the platform 2 shaking and the directional fluctuation caused by the drift.
However, the posture sensor does not measure the direction of the directional axis but suppresses time drift. Since the band of the attitude sensor is usually narrower than that of the inertial sensor, the inertial sensor takes charge of the high frequency side where space stability is required. However, if the oscillation frequency to be stabilized is within the band of the attitude sensor, one or a plurality of inertial sensors may be replaced with the attitude sensor.
[0049]
【The invention's effect】
  A space stabilization device according to the present invention is a device configuration for stabilizing and controlling the directional axis direction of a payload composed of an optical device or a communication antenna mounted on a platform that swings with respect to an inertial space, with respect to the inertial space, The payload components detect motion information with respect to the inertial space of a plurality of directional axis components (optical system elements or radio wave system elements) that contribute to the determination of the directional axis direction of the payload.pluralWith sensor,UpAnd directional axis fluctuation estimation means for estimating fluctuations in the directional axis direction of the payloadThe Each of the sensors detects, as the movement information, fluctuation information of one or both of translation and rotation with respect to the inertial space for each directional axis component. And the said directional axis fluctuation | variation estimation means synthesize | combines each said fluctuation | variation information for every said directional axis component from each said sensor using the sensitivity information of the said directional axis fluctuation | variation determined for every said directional axis | shaft component. An operation is performed to estimate the fluctuation of the payload in the direction of the directional axis. For this reason,Stable, wideband, high-precision space stabilization control can be performed without being restricted by the rigidity of the payload and platform. In addition, since the platform and payload do not require high mechanical rigidity, the platform and payload can be significantly reduced in weight.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a platform and a payload provided with a space stabilization device according to Embodiment 1 of the present invention;
FIG. 2 is a diagram showing an arrangement example of inertial sensors according to Embodiment 1 of the present invention.
FIG. 3 is a functional block diagram illustrating space stabilization control according to Embodiment 1 of the present invention.
FIG. 4 is a configuration diagram showing a platform and a payload provided with a space stabilization device according to Embodiment 3 of the present invention;
FIG. 5 is a functional block diagram illustrating space stabilization control according to Embodiment 3 of the present invention.
FIG. 6 is a functional block diagram illustrating space stabilization control according to another example of the third embodiment of the present invention.
FIG. 7 is a configuration diagram showing a platform including a space stabilization device and a payload according to a fourth embodiment of the present invention.
FIG. 8 is a configuration diagram showing a platform including a space stabilization device and a payload according to a fifth embodiment of the present invention.
FIG. 9 is a configuration diagram showing a platform and a payload provided with a space stabilization device according to Embodiment 6 of the present invention;
FIG. 10 is a functional block diagram illustrating space stabilization control according to Embodiment 6 of the present invention.
[Explanation of symbols]
1 inertial system, 2,2a platform, 3,3a payload,
4 Payload orientation axis, 5 platform swing, 6, 6a inertial sensor,
7 Directional axis fluctuation estimation unit, 8 Drive control device, 9 Actuator,
10, 10a Driving mirror as a directional axis determining element,
11 Image plane detector as a directional axis determining element,
12, 12a Primary mirror as a directional axis determining element,
13, 13a Secondary mirror as a directional axis determining element, 14 Target directional angle,
15 estimated fluctuation, 16 fluctuation compensation control section, 16a error / variation compensation control section,
18 Relative sensor, 19 Payload mount as reference part,
21 primary radiator as a directional axis determining element, 22 pointing error detector,
25 Error compensation controller.

Claims (11)

In a space stabilization device for stabilizing and controlling the direction of the directional axis of a payload composed of an optical device or a communication antenna mounted on a platform that swings relative to the inertial space,
A plurality of sensors for detecting motion information with respect to an inertial space of a plurality of optical system elements or radio wave system elements (hereinafter referred to as directional axis constituent elements) that contribute to determining a directional axis direction of the payload among the constituent elements of the payload; , and a directivity axis fluctuation estimation means for estimating the variation of the directivity axis of the upper SL payload,
Each of the sensors detects, as the movement information, fluctuation information of one or both of translation and rotation with respect to the inertial space for each directional axis component,
The directional axis fluctuation estimation means uses the sensitivity information of the directional axis fluctuation determined for each of the directional axis components to perform an operation for synthesizing the fluctuation information for the directional axis components from the sensors. And a space stabilization device for estimating fluctuations in the direction of the directional axis of the payload.   The calculation for synthesizing each variation information by the directional axis variation estimation means is to integrate the variation information using a predetermined numerical value as the sensitivity information as a coefficient of each variation information. Item 1. A space stabilization device according to item 1. As the sensor for detecting the motion information of the directional axis component relative to the inertial space, the inertial sensor installed directly on the directional axis component, or the mechanical rigidity of the directional axis component itself and the directional axis component is space stabilization control. space stabilizer according to claim 1 or 2, characterized in that it comprises an inertial sensor installed in high member than the band. The inertial sensor detects motion information with respect to the inertial space of some directional axis components in the plurality of directional axis components, and detects the motion information with respect to the inertial space of other directional axis components, A relative sensor that detects relative motion information of the directional axis component with respect to the installation part of the inertial sensor and detects motion information with respect to the inertial space by combining the detection information of the inertial sensor. 3. The space stabilization device according to 3 . In addition to the plurality of sensors for detecting movement information with respect to the inertial space of the plurality of directional axis components, the movement of the reference part with respect to the inertial space is provided with a reference portion having a mechanical rigidity higher than that of the space stabilization control band. An inertial sensor for detecting information is provided in the reference part, and as the sensor for detecting movement information with respect to the inertial space of the directional axis component, relative movement information of the directional axis component with respect to the reference part is detected, space stabilizer according to any one of claims 1 to 4, characterized in that it comprises a relative sensor for detecting the motion information with respect to inertial space by combining the motion information of the reference portion. The relative sensor for detecting the relative motion information of the directional axis component is directly installed on the directional axis component, or the mechanical rigidity of itself and the directional axis component is the space stabilization control. 6. The space stabilization device according to claim 4 , wherein the space stabilization device is installed on a member higher than the band . One or portions relative relationship between the directional axes components are known the directional axes components, claim and providing a position sensor for detecting an attitude to the external environment other than inertial space 1-6 The space stabilization apparatus in any one of. Fluctuation control means for estimating the fluctuation in the directional axis direction in real time by the directional axis fluctuation estimation means and outputting a compensation command for compensating for the estimated fluctuation; and the payload of the payload by the compensation command from the fluctuation compensation control means space stabilizer according to any one of claims 1 to 7, characterized in that an actuator for changing the directivity direction. The directional axis fluctuation estimating means also estimates the rotation fluctuation of the payload around the directional axis based on detection information from the sensor, and the actuator compensates for the estimated designated axial direction / rotational fluctuation. 9. The space stabilization device according to claim 8 , wherein the space stabilization device is controlled by a compensation command from the fluctuation compensation control means. A pointing error detecting means for detecting an error of the payload with respect to a target pointing direction; and an error compensation control means for outputting a command for compensating the error. The space stabilization device according to claim 8 , wherein the space stabilization device is arranged in a preceding stage to track the directional axis direction of the payload in the target directional direction. A pointing error detection means for detecting an error of the payload in the pointing axis direction with respect to the target pointing direction is provided, and the fluctuation compensation control means uses the error information from the pointing error detection means as the estimated fluctuation information from the pointing axis fluctuation estimation means. The space stabilization apparatus according to claim 8 or 9, wherein a compensation command that compensates for the error together with the estimated variation is output to track the directional axis direction of the payload to the target directional direction.

Images