JP2004085473A - Distance measuring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a distance measuring system capable of quickly and precisely measuring a distance regardless of the distance to a target. <P>SOLUTION: A bandwidth of a scanning signal generated by a signal generator 12 according to the distance X operated by a distance operator 17 is controlled. <P>COPYRIGHT: (C)2004,JPO

Description

ここで、Δｆ＜＜ｆ_Ｗであるため、式（１０）は次のようになる。
Δｘ≒ｖ・Δｆ／（２ｆ_Ｗ ^２）　　　　　　　　　　（１１）
【００３３】
したがって、掃引ステップ幅Δｆが一定の場合、再現周波数間隔ｆ_Ｗが小さくなる程（距離ｘが大きくなる程）、分解能Δｘが劣化する。よって、常に分解能Δｘを一定にするためには、距離ｘが大きくなるにしたがって掃引ステップ幅Δｆを小さくする必要がある。
この実施の形態２では、ステップ幅制御器２０が、距離演算器１７により演算された距離ｘが変化しても、Δｆ／（２ｆ_Ｗ ^２）が一定になるように掃引ステップ幅Δｆを制御する。
【００３４】
以上で明らかなように、この実施の形態２によれば、距離演算器１７により演算された距離ｘに応じて信号発生器１２から発信される掃引信号の掃引ステップ幅Δｆを制御するように構成したので、目標物１１までの距離に関わらず、距離ｘの分解能Δｘが一定になる結果、高精度に距離を測定することができる効果を奏する。
【００３５】
実施の形態３．
上記実施の形態１では、帯域幅制御器１８が目標物１１までの距離ｘに応じて信号発生器１２から発信される掃引信号の帯域幅を制御し、上記実施の形態２では、ステップ幅制御器２０が目標物１１までの距離ｘに応じて信号発生器１２から発信される掃引信号の掃引ステップ幅Δｆを制御するものについて示したが、図５に示すように、帯域幅制御器１８とステップ幅制御器２０の双方を搭載して、信号発生器１２から発信される掃引信号の帯域幅と掃引ステップ幅Δｆの両方を制御するようにしてもよい。
これにより、目標物１１までの距離に関わらず、迅速かつ高精度に距離を測定することができる効果を奏する。
【００３６】
実施の形態４．
図６はこの発明の実施の形態４による距離測定装置を示す構成図であり、図において、図５と同一符号は同一または相当部分を示すので説明を省略する。
２１は目標物１１の停止位置を示す停止位置指令を出力する停止位置指令器である。なお、停止位置指令器２１は、例えば、目標物１１が工作機械のアームに相当する場合、そのアームを目標位置に停止させる位置決め制御を実施する際、そのアームの目標位置を示す停止位置指令を工作機械に出力する制御回路に該当し、その停止位置指令を帯域幅制御器１８及びステップ幅制御器２０にも出力するようにしている。
【００３７】
上記実施の形態１〜３では、帯域幅制御器１８及びステップ幅制御器２０が距離演算器１７により演算された距離ｘに応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するものについて示したが、例えば、距離演算器１７の演算結果が出力されていない初期段階では、帯域幅制御器１８及びステップ幅制御器２０が停止位置指令器２１から出力される停止位置指令を入力し、その停止位置指令が示す目標物１１の停止位置に応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにしてもよい。
【００３８】
上記実施の形態１〜３の場合、距離演算器１７の演算結果が出力されていない初期段階では、掃引信号の帯域幅や掃引ステップ幅Δｆを予め用意されている初期値に設定する必要があるが、この実施の形態４では、目標物１１の停止位置を示す停止位置指令を入力するようにしているので、距離演算器１７の演算結果が出力されていない初期段階でも、目標物１１までの概略の距離ｘを把握することができる。
したがって、掃引信号の帯域幅や掃引ステップ幅Δｆを初期値に設定する場合よりも、掃引信号の帯域幅や掃引ステップ幅Δｆを適正化することができる。
この実施の形態４によれば、初期段階から高精度に距離を測定することができる効果を奏する。
【００３９】
なお、この実施の形態４では、距離演算器１７の演算結果が出力されていない初期段階では、帯域幅制御器１８及びステップ幅制御器２０が停止位置指令器２１から出力される停止位置指令にしたがって掃引信号の帯域幅や掃引ステップ幅Δｆを制御し、距離演算器１７から演算結果である距離ｘを受けると、以後、その距離ｘに応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御することを想定しているが、距離演算器１７の演算結果が出力されていない初期段階以外のときも、停止位置指令器２１から出力される停止位置指令にしたがって掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにしてもよい。
【００４０】
実施の形態５．
図７はこの発明の実施の形態５による距離測定装置を示す構成図であり、図において、図５と同一符号は同一または相当部分を示すので説明を省略する。
２２は距離演算器１７により今回演算された距離ｘ１と前回演算された距離ｘ０とを比較して、目標物１１の移動方向を判定する距離比較器（制御手段）である。
【００４１】
上記実施の形態１〜３では、帯域幅制御器１８及びステップ幅制御器２０が距離演算器１７により演算された距離ｘに応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するものについて示したが、目標物１１が絶えず移動しているような場合、定在波検出器１４が定在波の振幅Ａを検出してから、距離演算器１７が距離ｘを演算するまでの間も移動することが考えられるので、迅速かつ高精度に距離を測定するために制御した掃引信号の帯域幅や掃引ステップ幅Δｆが最適値でなくなることが起こり得る。
【００４２】
そこで、この実施の形態５では、距離比較器２２が距離演算器１７により今回演算された距離ｘ１と前回演算された距離ｘ０とを比較して、目標物１１の移動方向を判定し、帯域幅制御器１８及びステップ幅制御器２０が、目標物１１の移動方向を考慮して、掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにする。
【００４３】
具体的には、目標物１１の移動方向が定在波検出器１４から遠ざかる方向にある場合には、距離比較器２２が距離演算器１７により演算された距離ｘ１に対して所定の設定値を加算し、帯域幅制御器１８及びステップ幅制御器２０が、その加算結果に応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにする。
一方、目標物１１の移動方向が定在波検出器１４に近づく方向にある場合には、距離比較器２２が距離演算器１７により演算された距離ｘ１から所定の設定値を減算し、帯域幅制御器１８及びステップ幅制御器２０が、その減算結果に応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにする。
これにより、目標物１１が絶えず移動しているような場合でも、迅速かつ高精度に距離を測定することができる効果を奏する。
【００４４】
実施の形態６．
上記実施の形態５では、距離演算器１７により今回演算された距離ｘ１と前回演算された距離ｘ０とを比較して目標物１１の移動方向を判定し、その移動方向を考慮して、掃引信号の帯域幅や掃引ステップ幅Δｆを制御するものについて示したが、距離演算器１７により今回演算された距離ｘ１と前回演算された距離ｘ０とを比較して目標物１１の移動位置を予測し、その移動位置を考慮して、掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにしてもよい。
【００４５】
具体的には、距離比較器２２が距離演算器１７により今回演算された距離ｘ１と前回演算された距離ｘ０から移動距離ｘ０−ｘ１を計算するとともに、前回演算時ｔ０と今回演算時ｔ１の時間差ｔ０−ｔ１を計算する。
そして、距離比較器２２は、その移動距離ｘ０−ｘ１を時間差ｔ０−ｔ１で除算して、目標物１１の移動速度ｅを計算する。
ｅ＝（ｘ０−ｘ１）／（ｔ０−ｔ１）　　　　　　　　　（１２）
距離比較器２２は、上記のようにして、目標物１１の移動速度ｅを計算すると、定在波検出器１４が定在波の振幅Ａを検出してから、距離演算器１７が距離ｘを演算するまでに要する時間Ｔと、目標物１１の移動速度ｅと、距離演算器１７により今回演算された距離ｘ１とから目標物１１の移動位置ｘ２を予測する。
ｘ２＝ｘ１＋ｅ・Ｔ　　　　　　　　　　　　　　　　　（１３）
【００４６】
帯域幅制御器１８及びステップ幅制御器２０は、距離比較器２２が目標物１１の移動位置ｘ２を予測すると、その移動位置ｘ２に応じて掃引信号の帯域幅や掃引ステップ幅Δｆを制御するようにする。
これにより、目標物１１が絶えず移動しているような場合でも、迅速かつ高精度に距離を測定することができる効果を奏する。
【００４７】
実施の形態７．
図８はこの発明の実施の形態７による距離測定装置を示す構成図であり、図において、図４と同一符号は同一または相当部分を示すので説明を省略する。
２３は極値周波数検出器１５が定在波の振幅Ａが極小値（または極大値）を取る掃引信号の周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）を検出すると、掃引信号の伝搬速度ｖを周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）で除算して目標物１１までの距離ｘを演算する距離演算器（距離演算手段）である。
【００４８】
上記実施の形態１〜６では、再現周波数間隔演算器１６が極値周波数検出器１５により検出された周波数ｆ_ｉ，ｆ_ｉ＋ｊから再現周波数間隔ｆ_Ｗを求め、距離演算器１７が掃引信号の伝搬速度ｖを再現周波数間隔ｆ_Ｗで除算して目標物１１までの距離ｘを演算するものについて示したが、極値周波数検出器１５が定在波の振幅Ａが極小値（または極大値）を取る掃引信号の周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）を検出すると、距離演算器２３が掃引信号の伝搬速度ｖを周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）で除算して目標物１１までの距離ｘを演算するようにしてもよい。
【００４９】
即ち、この実施の形態７では、再現周波数間隔演算器１６を搭載せず、下記に示すように、定在波の振幅Ａが極小値（または極大値）を取る掃引信号の周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）に基づいて目標物１１までの距離ｘを演算する（図９を参照）。
ｘ＝ｖ／（２ｆ_ｍｉｎ）　　　　　　　　　　　　（１４）
ｘ＝ｖ／（４ｆ_ｍａｘ）　　　　　　　　　　　　（１５）
【００５０】
ここで、例えば、掃引信号の伝搬速度ｖが３×１０^８ｍ／ｓ、距離ｘの測定範囲が１ｃｍ＜ｘ＜２ｃｍであるとすると、測定に必要な周波数ｆ_ｍｉｎの帯域幅は７．５ＧＨｚとなる。また、測定に必要な周波数ｆ_ｍａｘの帯域幅は３．７５ＧＨｚとなる。
７．５ＧＨｚ＜ｆ_ｍｉｎ＜１５ＧＨｚ
３．７５ＧＨｚ＜ｆ_ｍａｘ＜７．５ＧＨｚ
同様の条件により、上記実施の形態１の式（４）に当て嵌めると、測定に必要な再現周波数間隔ｆ_Ｗは７．５ＧＨｚから１５ＧＨｚの範囲となる。
７．５ＧＨｚ＜ｆ_Ｗ＜１５ＧＨｚ
【００５１】
ただし、上記実施の形態１〜６では、少なくとも極小値（または極大値）となる周波数を２つ見つけなければ、再現周波数間隔ｆ_Ｗを求めることができないため、測定に必要な周波数ｆの帯域幅は３０ＧＨｚとなる。即ち、距離ｘの測定範囲の下限値である１ｃｍに着目すると、その下限値に対応する再現周波数間隔ｆ_Ｗの上限値（＝１５ＧＨｚ）において、±１５ＧＨｚの帯域幅が必要となるので、測定に必要な周波数ｆの帯域幅は３０ＧＨｚとなる。
したがって、この実施の形態７によれば、定在波の振幅Ａが極小値を取る掃引信号の周波数ｆ_ｍｉｎを検出する場合、上記実施の形態１〜６よりも、掃引信号の帯域幅を１／４にすることができるため、掃引時間を短縮することができる。なお、定在波の振幅Ａが極大値を取る掃引信号の周波数ｆ_ｍａｘを検出する場合には、上記実施の形態１〜６よりも、掃引信号の帯域幅を１／８にすることができる。
【００５２】
また、距離ｘの分解能Δｘについて考えると、信号発生器１２の掃引開始周波数をｆ_０、掃引ステップ幅をΔｆ、ステップ数をｎとすると、信号発生器１２の駆動周波数ｆ_ｎは、次のように表される。
ｆ_ｎ＝ｆ_０＋Δｆ・（ｎ−１）　　　　　　　　　　　　（１６）
駆動周波数ｆ_ｎにおいて、振幅Ａが極小値（または極大値）となる距離をｘ_ｎとすると、分解能Δｘは次のように表される。

【００５３】
式（１７）において、ｆ_０＞＞Δｆとすると、式（１７）は次のように表される。
Δｘ≒ｖ／｛２・Δｆ（ｎ＋ｆ_０／Δｆ）^２｝　　（１８）
式（１８）は、掃引ステップ数ｎの値が小さい程、分解能Δｘが粗いことを示している。
したがって、この実施の形態７におけるステップ幅制御器２０は、分解能Δｘが一定になるように、ステップ数ｎの値に応じて掃引ステップ幅Δｆを変化させる。
【００５４】
例えば、総ステップ数が１００、ｎ＝１，２，・・・，１００のときの掃引ステップ幅がΔｆ_１，Δｆ_２，・・・，Δｆ_１００であるときは、１＋ｆ_０／Δｆ_１＝２＋ｆ_０／Δｆ_２＝・・・＝ｎ＋ｆ_０／Δｆ_ｎとなれば、式（１８）の右辺は一定値となる。
また、式（１８）の右辺を一定値にするために、例えば、ステップ幅制御器２０のステップ幅を次のようにすれば、一定の分解能にて測定が可能となる。

【００５５】
以上で明らかなように、この実施の形態７によれば、極値周波数検出器１５が定在波の振幅Ａが極小値（または極大値）を取る掃引信号の周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）を検出すると、距離演算器２３が掃引信号の伝搬速度ｖを周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）で除算して目標物１１までの距離ｘを演算するように構成したので、上記実施の形態１〜６よりも迅速に距離を測定することができる効果を奏する。
【００５６】
なお、この実施の形態７では、ステップ幅制御器２０が目標物１１までの距離ｘに応じて信号発生器１２から発信される掃引信号の掃引ステップ幅Δｆを制御するものについて示したが、帯域幅制御器１８が目標物１１までの距離ｘに応じて信号発生器１２から発信される掃引信号の帯域幅を制御するようにしてもよい。
【００５７】
実施の形態８．
図１０はこの発明の実施の形態８による距離測定装置を示す構成図であり、図において、図８と同一符号は同一または相当部分を示すので説明を省略する。
２４は極値周波数検出器１５により検出された周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）の検出順位を計数する極値カウンタ（距離演算手段）である。
【００５８】
上記実施の形態７では、特に言及していないが、信号発生器１２は、通常、周波数ｆを一番低い状態から除々に高くしていくため、極値周波数検出器１５は、定在波の振幅Ａが極小値（または極大値）を取る複数の周波数のうち、最も周波数が低い周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）を検出する。
しかし、周波数が低い周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）よりも、周波数が高い周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）の方が、図９に示すように、振幅Ａの極小値（または極大値）の検出点が急峻になり、検出精度が向上すると考えられる。
【００５９】
そこで、この実施の形態８では、極値カウンタ２４が極値周波数検出器１５により検出された周波数ｆ_ｍｉｎ（またはｆ_ｍａｘ）の検出順位ｍを計数し、その検出順位ｍを考慮して目標物１１までの距離ｘを演算する。
ｘ＝ｍ・ｖ／（２ｆ_ｍｉｎ）　　　　　　　　（１９）
ｘ＝（ｍ−１／２）・ｖ／（２ｆ_ｍａｘ）　　（２０）
以下、上記実施の形態７と同様であるため説明を省略する。
この実施の形態８によれば、上記実施の形態７よりも、距離の測定精度を高めることができる効果を奏する。
【００６０】
実施の形態９．
図１２はこの発明の実施の形態９による距離測定装置を示す構成図であり、図において、図８と同一符号は同一または相当部分を示すので説明を省略する。
２５は定在波検出部１４の検出結果をフーリエ変換して、再現周波数間隔ｆ_Ｗを検出するフーリエ変換器（周波数検出手段）である。
【００６１】
上記実施の形態１〜６では、極値周波数検出器１５が定在波検出器１４により検出された定在波の振幅Ａが極小値を取る掃引信号の周波数ｆ_ｉ，ｆ_ｉ＋ｊを検出し、再現周波数間隔演算器１６が掃引信号の周波数ｆ_ｉ，ｆ_ｉ＋ｊから再現周波数間隔ｆ_Ｗを求めるものについて示したが、フーリエ変換器２５が定在波検出部１４の検出結果をフーリエ変換して、再現周波数間隔ｆ_Ｗを検出するようにしてもよい。
【００６２】
具体的には、フーリエ変換器２５は、定在波検出部１４の検出結果をフーリエ変換して定在波の振幅Ａのスペクトルを解析すると特徴的な周波数が現われ、その特徴的な周波数が再現周波数間隔ｆ_Ｗに相当するので、その特徴的な周波数を距離演算器２３に出力するようにする。
これにより、迅速かつ高精度に再現周波数間隔ｆ_Ｗを検出することができるとともに、目標物１１を複数設けた場合においても、同時に複数の目標物による定在波の特徴的な周波数を求めることが可能となる。
【００６３】
【発明の効果】
以上のように、この発明によれば、距離演算手段により演算された距離に応じて信号発信手段から発信される掃引信号の帯域幅を制御するように構成したので、目標物までの距離に関わらず、迅速に距離を測定することができる効果がある。
【００６４】
この発明によれば、距離演算手段により演算された距離に応じて信号発信手段から発信される掃引信号の掃引ステップ幅を制御するように構成したので、目標物までの距離に関わらず、高精度に距離を測定することができる効果がある。
【００６５】
この発明によれば、距離演算手段により演算された距離に応じて信号発信手段から発信される掃引信号の帯域幅を制御するとともに、その掃引信号の掃引ステップ幅を制御するように構成したので、目標物までの距離に関わらず、迅速かつ高精度に距離を測定することができる効果がある。
【００６６】
この発明によれば、周波数検出手段により検出された複数の周波数間の差分周波数を求め、掃引信号の伝搬速度を当該差分周波数で除算して目標物までの距離を演算するように構成したので、構成の複雑化を招くことなく、高精度に目標物までの距離を演算することができる効果がある。
【００６７】
この発明によれば、目標物の停止位置を示す停止位置指令を入力すると、その停止位置を考慮して、掃引信号の帯域幅又は掃引ステップ幅を制御するように構成したので、停止位置付近を高精度に距離を測定することができる効果がある。
【００６８】
この発明によれば、今回演算された距離と前回演算された距離とを比較して目標物の移動方向を判定し、その移動方向を考慮して、掃引信号の帯域幅又は掃引ステップ幅を制御するように構成したので、目標物が絶えず移動しているような場合でも、迅速かつ高精度に距離を測定することができる効果がある。
【００６９】
この発明によれば、今回演算された距離と前回演算された距離とを比較して目標物の移動位置を予測し、その移動位置を考慮して、掃引信号の帯域幅又は掃引ステップ幅を制御するように構成したので、目標物が絶えず移動しているような場合でも、迅速かつ高精度に距離を測定することができる効果がある。
【００７０】
この発明によれば、周波数検出手段が周波数を検出すると、掃引信号の伝搬速度を当該周波数で除算して目標物までの距離を演算するように構成したので、更に迅速に距離を測定することができる効果がある。
【００７１】
この発明によれば、周波数検出手段により検出された周波数の検出順位を計数し、その検出順位を考慮して目標物までの距離を演算するように構成したので、更に距離の測定精度を高めることができる効果がある。
【００７２】
この発明によれば、定在波検出手段の検出結果をフーリエ変換して、極値を取る各掃引信号の周波数間の差分周波数を検出するように構成したので、複数の目標物までの距離を迅速かつ高精度に測定することができる効果がある。
【図面の簡単な説明】
【図１】この発明の実施の形態１による距離測定装置を示す構成図である。
【図２】定在波の振幅を示す説明図である。
【図３】この発明の実施の形態１による距離測定装置を示す構成図である。
【図４】この発明の実施の形態２による距離測定装置を示す構成図である。
【図５】この発明の実施の形態３による距離測定装置を示す構成図である。
【図６】この発明の実施の形態４による距離測定装置を示す構成図である。
【図７】この発明の実施の形態５による距離測定装置を示す構成図である。
【図８】この発明の実施の形態７による距離測定装置を示す構成図である。
【図９】定在波の振幅を示す説明図である。
【図１０】この発明の実施の形態８による距離測定装置を示す構成図である。
【図１１】伝送路上に発生する定在波を示す説明図である。
【図１２】この発明の実施の形態９による距離測定装置を示す構成図である。
【図１３】従来の距離測定装置を示す構成図である。
【図１４】目標物までの距離と掃引信号の帯域幅の関係を示す説明図である。
【符号の説明】
１１　目標物、１２　信号発生器（信号発信手段）、１３　伝送路、１４　定在波検出器（定在波検出手段）、１５　極値周波数検出器（周波数検出手段）、１６　再現周波数間隔演算器（距離演算手段）、１７　距離演算器（距離演算手段）、１８　帯域幅制御器（制御手段）、１９　極値カウンタ、２０　ステップ幅制御器（制御手段）、２１　停止位置指令器、２２　距離比較器（制御手段）、２３　距離演算器（距離演算手段）、２４　極値カウンタ（距離演算手段）、２５　フーリエ変換器（周波数検出手段）。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a distance measuring device for measuring a distance to a target.
[0002]
[Prior art]
FIG. 13 is a configuration diagram showing a conventional distance measuring device shown in, for example, “IEICE Technical Report {Vol. 100} No. 695 P161 to P166”. In FIG. The signal generator 3 for transmitting the sweep signal transmits the sweep signal transmitted from the signal generator 2 toward the target 1, and a stationary signal generated from the sweep signal and the sweep signal reflected on the target 1. An antenna for receiving a wave, 4 a standing wave detector for detecting the amplitude of the standing wave received by the antenna 3, 5 a frequency controller for controlling the frequency of a sweep signal transmitted from the signal generator 2, 6 Is a distance for detecting the frequency f of the sweep signal in which the amplitude of the standing wave detected by the standing wave detector 4 takes a minimum value, and calculating the distance x from the antenna 3 to the target 1 based on the frequency f. It is an arithmetic unit.
[0003]
Next, the operation will be described.
When measuring the distance from the antenna 3 to the target 1, the signal generator 2 transmits a sweep signal while sequentially switching the frequency under the instruction of the frequency controller 5. However, the frequency controller 5 changes the frequency f of the sweep signal transmitted from the signal generator 2 in accordance with the distance to the target 1, and the bandwidth of the frequency f varies with the distance to the target 1. It does not change. In addition, the sweep step width of the frequency f when the frequency is sequentially switched is always the same.
[0004]
When receiving the sweep signal from the signal generator 2, the antenna 3 transmits the sweep signal toward the target 1.
The antenna 3 receives a sweep signal transmitted toward the target 1 and a standing wave generated from the sweep signal reflected by the target 1.
When the antenna 3 receives a standing wave, the standing wave detector 4 detects the amplitude of the standing wave.
[0005]
When the standing wave detector 4 detects the amplitude of the standing wave, the distance calculator 6 outputs the frequency f of the sweep signal when the amplitude of the standing wave becomes a minimum value from the frequency controller 5._N, F_{N + k}Enter Where f_NIs the frequency of the sweep signal related to the Nth detected minimum value, f_{N + k}Is the frequency of the sweep signal related to the N + k-th detected minimum value.
Then, the distance calculator 6 calculates the frequency f of the sweep signal as shown below._NAnd frequency f_{N + k}Frequency difference f_pAnd the frequency difference f_pIs calculated based on the distance x from the antenna 3 to the target 1.
f_p= F_{N + k}−f_N(1)
x = k · v / (2f_p) (2)
Here, v is the propagation speed of the sweep signal.
[0006]
The minimum detection distance x in the distance calculator 6 in FIG._minAnd the bandwidth f of the sweep signal_WmaxHas the following relationship, the smaller the distance x to the target 1, the closer the bandwidth f of the sweep signal_WmaxNeeds to be widened (see FIG. 14). Therefore, the frequency controller 5 sets the minimum detection distance x so that the distance x to the target 1 can be measured whether the distance x is short or long._minAnd the bandwidth f of the sweep signal_WmaxIs set.
f_Wmax= V / (2x_min) (3)
[0007]
[Problems to be solved by the invention]
Since the conventional distance measuring device is configured as described above, it can measure whether the distance to the target 1 is short or long. However, the minimum detection distance x_minAnd the bandwidth f of the sweep signal_WmaxIs set, when the distance to the target 1 increases, the frequency is swept to an unnecessary frequency region. Therefore, there is a problem that it takes a long time to obtain a measurement result because the frequency sweep time becomes long.
Further, even if the distance to the target 1 changes, the sweep step width of the sweep signal when changing the frequency sequentially does not change, so that as the distance to the target 1 increases, the resolution deteriorates and the measurement accuracy decreases. There was a problem of deterioration.
[0008]
The present invention has been made to solve the above-described problems, and has as its object to provide a distance measuring device that can quickly and accurately measure a distance regardless of a distance to a target.
[0009]
[Means for Solving the Problems]
A distance measuring device according to the present invention controls a bandwidth of a sweep signal transmitted from a signal transmitting unit according to a distance calculated by a distance calculating unit.
[0010]
The distance measuring device according to the present invention controls the sweep step width of the sweep signal transmitted from the signal transmitting means according to the distance calculated by the distance calculating means.
[0011]
The distance measuring device according to the present invention controls the bandwidth of the sweep signal transmitted from the signal transmitting means according to the distance calculated by the distance calculating means, and controls the sweep step width of the sweep signal. Things.
[0012]
The distance measuring device according to the present invention calculates a difference frequency between a plurality of frequencies detected by the frequency detection means, and calculates a distance to a target by dividing a propagation speed of the sweep signal by the difference frequency. Things.
[0013]
The distance measuring device according to the present invention is configured such that, when a stop position command indicating a stop position of a target is input, the bandwidth of the sweep signal or the sweep step width is controlled in consideration of the stop position.
[0014]
The distance measuring device according to the present invention compares the distance calculated this time with the distance calculated last time to determine the moving direction of the target, and in consideration of the moving direction, the bandwidth or the sweep step of the sweep signal. The width is controlled.
[0015]
The distance measuring device according to the present invention compares a currently calculated distance with a previously calculated distance to predict a moving position of a target, and in consideration of the moving position, a bandwidth of a sweep signal or a sweep step. The width is controlled.
[0016]
In the distance measuring device according to the present invention, when the frequency detecting means detects the frequency, the propagation speed of the sweep signal is divided by the frequency to calculate the distance to the target.
[0017]
The distance measuring apparatus according to the present invention is configured to count the order of detection of the frequencies detected by the frequency detecting means and calculate the distance to the target in consideration of the order of detection.
[0018]
The distance measuring apparatus according to the present invention is configured to perform a Fourier transform on a detection result of the standing wave detecting means to detect a difference frequency between the frequencies of the respective sweep signals having an extreme value.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
Embodiment 1 FIG.
FIG. 1 is a block diagram showing a distance measuring apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 11 denotes a target, and 12 denotes a signal generator for transmitting a sweep signal toward the target 11 while sequentially switching frequencies. (Signal transmission means), 13 is a transmission path. However, the transmission path 13 may be wired or wireless (in the air). The target 11 can be arbitrarily selected according to the transmission path 13 and the type of the sweep signal.
Reference numeral 14 denotes a standing wave detector (standing wave detecting means) for detecting the amplitude A of a standing wave generated from the sweep signal transmitted from the signal generator 12 and the sweep signal reflected by the target 11, and 15 denotes a standing wave detector. The frequency f of the sweep signal in which the amplitude A of the standing wave detected by the standing wave detector 14 takes a minimum value._i, F_{i + j}Is an extreme frequency detector (frequency detecting means).
[0020]
16 is the frequency f of the sweep signal detected by the extreme frequency detector 15_iAnd frequency f_{i + j}Difference frequency (hereinafter, reproduction frequency interval f_WA reproduction frequency interval calculator 17 for determining the propagation speed v of the sweep signal is used to calculate the reproduction frequency interval f._WIs a distance calculator that calculates the distance x to the target 11 by dividing by. It should be noted that a distance calculation means is constituted by the reproduction frequency interval calculator 16 and the distance calculator 17.
Reference numeral 18 denotes a bandwidth controller (control means) that controls the bandwidth of the sweep signal transmitted from the signal generator 12 according to the distance x calculated by the distance calculator 17.
[0021]
Next, the operation will be described.
When measuring the distance from the standing wave detector 14 to the target 11, the signal generator 12 transmits a sweep signal toward the target 11 while sequentially switching the frequency. However, the bandwidth of the sweep signal transmitted from the signal generator 12 is set by an instruction of the bandwidth controller 18.
As shown in FIG. 11, the sweep signal transmitted from the signal generator 12 is reflected by the target object 11 to generate a standing wave S on the transmission path 13. However, the following description is made on the assumption that the reflection coefficient Γ of the target 11 is “−1”.
[0022]
The standing wave detector 14 detects the amplitude A of the standing wave when the standing wave S is generated on the transmission line 13 by the signal generator 12 transmitting the sweep signal toward the target 11. .
The amplitude A of the standing wave is a waveform having a periodicity with respect to the frequency f of the sweep signal, as shown in FIG.
[0023]
When the standing wave detector 14 detects the amplitude A of the standing wave, the extreme frequency detector 15 detects the frequency f of the sweep signal at which the amplitude A of the standing wave takes the minimum value._i, F_{i + j}Is detected.
Here, the frequency of the sweep signal transmitted from the signal generator 12 is f_iAt this time, if the number of the minimum values of the standing wave S generated on the transmission line 13 is i (see FIG. 11), the distance x from the standing wave detector 14 to the target 11 is Become like
x = iv / (2f_i) (4)
Similarly, the frequency of the sweep signal transmitted from the signal generator 12 is f_{i + j}At this time, if the number of the minimum values of the standing wave S generated on the transmission line 13 is (i + j) (see FIG. 11), the distance x from the standing wave detector 14 to the target 11 is It looks like this:
x = (i + j) .v / (2f_{i + j}) (5)
[0024]
When i is eliminated from the equations (4) and (5), the following is obtained._WIt can be seen that the distance x can be obtained if the number j of the local minimum value is known.
x = j · v / ｛2 (f_{i + j}−f_i)｝
= Jv / (2f_W) (6)
[0025]
The reproduction frequency interval calculator 16 determines that the extreme frequency detector 15 has the frequency f of the sweep signal._i, F_{i + j}Is detected, the frequency f_{i + j}To frequency f_iIs subtracted to obtain the reproduction frequency interval f_WIs calculated.
f_W= F_{i + j}−f_i(7)
The distance calculating unit 17 calculates the reproduction frequency interval f_WIs calculated, the propagation speed v of the sweep signal and the reproduction frequency interval f_WIs substituted into Expression (6), and the distance x from the standing wave detector 14 to the target 11 is calculated.
[0026]
At this time, the number j of the local minimum values is determined by the frequency f from the local frequency detector 15 as shown in FIG._iThe number i of the minimum values of the standing wave S at the time_{i + j}Can be easily obtained by inputting the number (i + j) of the minimum values of the standing wave S at the time of (1) and providing an extreme value counter 19 that outputs the number j of the minimum values, which is the difference between them. For example, the frequency f at which the extreme frequency detector 15 always becomes j = 1_i, F_{i + 1}, The extreme value counter 19 is unnecessary. However, it is not necessary to limit to j = 1. For example, the frequency f at which the extreme frequency detector 15 always becomes j = 2_i, F_{i + 2}May be detected.
[0027]
When the distance calculator 17 calculates the distance x from the standing wave detector 14 to the target 11, the bandwidth controller 18 generates a signal according to the distance x to the target 11 in preparation for the next calculation. The bandwidth of the sweep signal transmitted from the detector 12 is controlled.
That is, as is clear from equation (6), the bandwidth controller 18 sets the reproduction frequency interval f as the distance x increases._WTherefore, as the distance x increases, for example, the number of sweep steps is reduced, and the bandwidth of the sweep signal is reduced. As a result, frequency sweeping in unnecessary frequency regions can be avoided, and the frequency sweeping time can be shortened.
[0028]
As is clear from the above, according to the first embodiment, the bandwidth of the sweep signal transmitted from the signal generator 12 is controlled according to the distance x calculated by the distance calculator 17. This has the effect that the distance can be quickly measured regardless of the distance to the target 11.
[0029]
In the first embodiment, the extreme frequency detector 15 detects the frequency f of the sweep signal in which the amplitude A of the standing wave takes the minimum value._i, F_{i + j}Is shown, but the frequency f 'of the sweep signal where the amplitude A of the standing wave takes the maximum value is shown._i, F '_{i + j}May be detected.
In this case, the distance x from the standing wave detector 14 to the target 11 is as follows.
x = (i'-1 / 2) .v / (2f '_i) (8)
x = (i '+ j'-1 / 2) .v / (2f'_{i + j}) (9)
Hereinafter, since it is the same, description is omitted.
[0030]
Embodiment 2 FIG.
FIG. 4 is a configuration diagram showing a distance measuring apparatus according to Embodiment 2 of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and a description thereof will be omitted.
Reference numeral 20 controls the sweep step width Δf of the sweep signal transmitted from the signal generator 12 in accordance with the distance x calculated by the distance calculator 17 (switching width when the signal generator 12 switches the frequency of the sweep signal). It is a step width controller (control means).
[0031]
In the first embodiment, the bandwidth controller 18 controls the bandwidth of the sweep signal transmitted from the signal generator 12 according to the distance x to the target 11, and the sweep step width Δf of the sweep signal is particularly changed. Although not shown, the step width controller 20 may control the sweep step width Δf of the sweep signal transmitted from the signal generator 12 according to the distance x to the target 11.
[0032]
That is, as described above, the distance x from the standing wave detector 14 to the target 11 can be calculated using Expression (6)._WIf the step width of the sweep signal is Δf, the resolution Δx is as follows.

Here, Δf << f_WTherefore, equation (10) becomes as follows.
Δx ≒ v · Δf / (2f_W ²) (11)
[0033]
Therefore, when the sweep step width Δf is constant, the reproduction frequency interval f_WIs smaller (the distance x is larger), the resolution Δx is degraded. Therefore, in order to keep the resolution Δx constant, it is necessary to reduce the sweep step width Δf as the distance x increases.
In the second embodiment, even if the distance x calculated by the distance calculator 17 changes, the step width controller 20 determines that Δf / (2f_W ²) Is controlled so that the sweep step width Δf is constant.
[0034]
As is apparent from the above, according to the second embodiment, the sweep step width Δf of the sweep signal transmitted from the signal generator 12 is controlled according to the distance x calculated by the distance calculator 17. Therefore, regardless of the distance to the target 11, the resolution Δx of the distance x becomes constant, so that there is an effect that the distance can be measured with high accuracy.
[0035]
Embodiment 3 FIG.
In the first embodiment, the bandwidth controller 18 controls the bandwidth of the sweep signal transmitted from the signal generator 12 in accordance with the distance x to the target 11, and in the second embodiment, the step width control is performed. Although the device 20 controls the sweep step width Δf of the sweep signal transmitted from the signal generator 12 according to the distance x to the target 11, the bandwidth controller 18 and the bandwidth controller 18 as shown in FIG. Both of the step width controllers 20 may be mounted to control both the bandwidth of the sweep signal transmitted from the signal generator 12 and the sweep step width Δf.
Accordingly, there is an effect that the distance can be measured quickly and accurately regardless of the distance to the target 11.
[0036]
Embodiment 4 FIG.
FIG. 6 is a configuration diagram showing a distance measuring apparatus according to Embodiment 4 of the present invention. In the figure, the same reference numerals as in FIG.
A stop position commander 21 outputs a stop position command indicating the stop position of the target 11. For example, when the target 11 corresponds to an arm of a machine tool, the stop position commander 21 issues a stop position command indicating a target position of the arm when performing positioning control for stopping the arm at the target position. This corresponds to a control circuit that outputs to the machine tool, and the stop position command is also output to the bandwidth controller 18 and the step width controller 20.
[0037]
Embodiments 1 to 3 show that the bandwidth controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf according to the distance x calculated by the distance calculator 17. However, for example, in an initial stage in which the calculation result of the distance calculator 17 is not output, the bandwidth controller 18 and the step width controller 20 input the stop position command output from the stop position commander 21, and The bandwidth of the sweep signal and the sweep step width Δf may be controlled according to the stop position of the target 11 indicated by the stop position command.
[0038]
In the first to third embodiments, in the initial stage in which the calculation result of the distance calculator 17 is not output, it is necessary to set the bandwidth of the sweep signal and the sweep step width Δf to the prepared initial values. However, in the fourth embodiment, since the stop position command indicating the stop position of the target 11 is input, even in the initial stage in which the calculation result of the distance calculator 17 is not output, the distance to the target 11 is not increased. The approximate distance x can be grasped.
Therefore, the bandwidth of the sweep signal and the sweep step width Δf can be optimized as compared with the case where the bandwidth of the sweep signal and the sweep step width Δf are set to the initial values.
According to the fourth embodiment, there is an effect that the distance can be measured with high accuracy from the initial stage.
[0039]
In the fourth embodiment, in the initial stage in which the calculation result of the distance calculator 17 is not output, the bandwidth controller 18 and the step width controller 20 transmit the stop position command output from the stop position command device 21 to the stop position command. Accordingly, when the bandwidth and the sweep step width Δf of the sweep signal are controlled and the distance x which is the calculation result is received from the distance calculator 17, the bandwidth and the sweep step width Δf of the sweep signal are controlled in accordance with the distance x thereafter. However, even in the initial stage when the calculation result of the distance calculator 17 is not output, the bandwidth of the sweep signal and the sweep step in accordance with the stop position command output from the stop position command device 21 are assumed. The width Δf may be controlled.
[0040]
Embodiment 5 FIG.
FIG. 7 is a block diagram showing a distance measuring apparatus according to Embodiment 5 of the present invention. In the figure, the same reference numerals as those in FIG.
Reference numeral 22 denotes a distance comparator (control means) that compares the distance x1 calculated this time by the distance calculator 17 with the distance x0 calculated last time to determine the moving direction of the target 11.
[0041]
Embodiments 1 to 3 show that the bandwidth controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf according to the distance x calculated by the distance calculator 17. However, in the case where the target 11 is constantly moving, the moving object moves from when the standing wave detector 14 detects the amplitude A of the standing wave to when the distance calculator 17 calculates the distance x. Therefore, the bandwidth of the sweep signal and the sweep step width Δf controlled for quickly and accurately measuring the distance may become non-optimal.
[0042]
Therefore, in the fifth embodiment, the distance comparator 22 compares the distance x1 calculated this time by the distance calculator 17 with the distance x0 calculated last time to determine the moving direction of the target 11, and determines the bandwidth. The controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf in consideration of the moving direction of the target 11.
[0043]
Specifically, when the moving direction of the target 11 is away from the standing wave detector 14, the distance comparator 22 sets a predetermined value to the distance x1 calculated by the distance calculator 17. The addition is performed, and the bandwidth controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf according to the addition result.
On the other hand, when the moving direction of the target 11 is in the direction approaching the standing wave detector 14, the distance comparator 22 subtracts a predetermined set value from the distance x1 calculated by the distance calculator 17 to obtain a bandwidth. The controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf according to the result of the subtraction.
Thus, even when the target 11 is constantly moving, the distance can be measured quickly and accurately.
[0044]
Embodiment 6 FIG.
In the fifth embodiment, the moving direction of the target 11 is determined by comparing the distance x1 calculated this time by the distance calculator 17 and the distance x0 calculated last time, and the sweep signal is considered in consideration of the moving direction. Controlling the bandwidth and the sweep step width Δf, the distance calculator 17 compares the distance x1 calculated this time with the distance x0 calculated last time to predict the moving position of the target 11, and The bandwidth of the sweep signal and the sweep step width Δf may be controlled in consideration of the moving position.
[0045]
Specifically, the distance comparator 22 calculates the moving distance x0−x1 from the distance x1 calculated this time by the distance calculator 17 and the distance x0 calculated last time, and also calculates the time difference between the previous calculation time t0 and the current calculation time t1. Calculate t0-t1.
Then, the distance comparator 22 calculates the moving speed e of the target 11 by dividing the moving distance x0-x1 by the time difference t0-t1.
e = (x0−x1) / (t0−t1) (12)
When the distance comparator 22 calculates the moving speed e of the target 11 as described above, the distance calculator 17 calculates the distance x after the standing wave detector 14 detects the amplitude A of the standing wave. The moving position x2 of the target 11 is predicted from the time T required for the calculation, the moving speed e of the target 11, and the distance x1 calculated this time by the distance calculator 17.
x2 = x1 + e · T (13)
[0046]
When the distance comparator 22 predicts the moving position x2 of the target 11, the bandwidth controller 18 and the step width controller 20 control the bandwidth of the sweep signal and the sweep step width Δf according to the moving position x2. To
Thus, even when the target 11 is constantly moving, the distance can be measured quickly and accurately.
[0047]
Embodiment 7 FIG.
FIG. 8 is a configuration diagram showing a distance measuring apparatus according to Embodiment 7 of the present invention. In the figure, the same reference numerals as in FIG.
Reference numeral 23 denotes a frequency f of the sweep signal in which the amplitude A of the standing wave takes the minimum value (or the maximum value) by the extreme frequency detector 15._min(Or f_max) Is detected, the propagation speed v of the swept signal is changed to the frequency f_min(Or f_max) Is a distance calculator (distance calculating means) that calculates the distance x to the target 11 by dividing the distance x by the distance.
[0048]
In the first to sixth embodiments, the reproduction frequency interval calculator 16 calculates the frequency f detected by the extreme frequency detector 15._i, F_{i + j}From the reproduction frequency interval f_WIs calculated, and the distance calculator 17 determines the propagation speed v of the sweep signal as the reproduction frequency interval f._W, The distance x to the target 11 is calculated, but the extreme frequency detector 15 detects the frequency f of the sweep signal in which the amplitude A of the standing wave takes the minimum value (or the maximum value)._min(Or f_max), The distance calculator 23 changes the propagation speed v of the sweep signal to the frequency f._min(Or f_max) May be used to calculate the distance x to the target 11.
[0049]
That is, in the seventh embodiment, the reproduction frequency interval calculator 16 is not mounted, and the frequency f of the sweep signal at which the amplitude A of the standing wave takes the minimum value (or the maximum value) is set as shown below._min(Or f_max) Is calculated based on the distance x to the target 11 (see FIG. 9).
x = v / (2f_min) (14)
x = v / (4f_max) (15)
[0050]
Here, for example, the propagation speed v of the sweep signal is 3 × 10⁸Assuming that the measurement range of m / s and the distance x is 1 cm <x <2 cm, the frequency f required for the measurement is_minIs 7.5 GHz. In addition, the frequency f required for measurement_maxIs 3.75 GHz.
7.5 GHz <f_min<15 GHz
3.75 GHz <f_max<7.5 GHz
Under the same conditions, when applied to the equation (4) of the first embodiment, the reproduction frequency interval f required for measurement is obtained._WIs in the range of 7.5 GHz to 15 GHz.
7.5 GHz <f_W<15 GHz
[0051]
However, in the first to sixth embodiments, if at least two frequencies having the minimum value (or the maximum value) are not found, the reproduction frequency interval f_WCannot be obtained, the bandwidth of the frequency f required for the measurement is 30 GHz. That is, when focusing on 1 cm which is the lower limit of the measurement range of the distance x, the reproduction frequency interval f corresponding to the lower limit is set._WIn the upper limit value (= 15 GHz), a bandwidth of ± 15 GHz is required, so that the bandwidth of the frequency f required for measurement is 30 GHz.
Therefore, according to the seventh embodiment, the frequency f of the sweep signal in which the amplitude A of the standing wave takes the minimum value is obtained._minIs detected, the bandwidth of the sweep signal can be reduced to 1/4 of that in Embodiments 1 to 6, so that the sweep time can be shortened. Note that the frequency f of the sweep signal in which the amplitude A of the standing wave takes the maximum value_maxIs detected, the bandwidth of the sweep signal can be reduced to 1/8 of that in the first to sixth embodiments.
[0052]
Considering the resolution Δx of the distance x, the sweep start frequency of the signal generator 12 is f₀When the sweep step width is Δf and the number of steps is n, the driving frequency f of the signal generator 12 is_nIs expressed as follows.
f_n= F₀+ Δf · (n−1) (16)
Drive frequency f_n, The distance at which the amplitude A has a minimum value (or a maximum value) is x_nThen, the resolution Δx is expressed as follows.

[0053]
In equation (17), f₀If >> f, equation (17) is expressed as follows.
Δx ≒ v / ｛2 ・ Δf (n + f₀/ Δf)²｝ (18)
Equation (18) indicates that the smaller the value of the sweep step number n, the coarser the resolution Δx.
Therefore, the step width controller 20 in the seventh embodiment changes the sweep step width Δf according to the value of the number of steps n so that the resolution Δx is constant.
[0054]
For example, when the total number of steps is 100 and n = 1, 2,...₁, Δf₂, ..., Δf₁₀₀Is 1 + f₀/ Δf₁= 2 + f₀/ Δf₂= ... = n + f₀/ Δf_nThen, the right side of Expression (18) becomes a constant value.
If the step width of the step width controller 20 is set as follows in order to set the right side of the equation (18) to a constant value, for example, the measurement can be performed with a constant resolution.

[0055]
As is clear from the above, according to the seventh embodiment, the extreme frequency detector 15 detects the frequency f of the sweep signal in which the amplitude A of the standing wave takes the minimum value (or the maximum value)._min(Or f_max), The distance calculator 23 changes the propagation speed v of the sweep signal to the frequency f._min(Or f_max) To calculate the distance x to the target 11, so that the distance can be measured more quickly than in the first to sixth embodiments.
[0056]
In the seventh embodiment, the step width controller 20 controls the sweep step width Δf of the sweep signal transmitted from the signal generator 12 in accordance with the distance x to the target 11. The width controller 18 may control the bandwidth of the sweep signal transmitted from the signal generator 12 according to the distance x to the target 11.
[0057]
Embodiment 8 FIG.
FIG. 10 is a configuration diagram showing a distance measuring apparatus according to Embodiment 8 of the present invention. In the figure, the same reference numerals as those in FIG. 8 denote the same or corresponding parts, and a description thereof will be omitted.
24 is the frequency f detected by the extreme frequency detector 15._min(Or f_max) Is an extreme value counter (distance calculation means) for counting the detection order.
[0058]
Although not particularly mentioned in the seventh embodiment, since the signal generator 12 usually gradually increases the frequency f from the lowest state, the extreme frequency detector 15 detects the standing wave. Among a plurality of frequencies in which the amplitude A takes a minimum value (or a maximum value), the frequency f having the lowest frequency f_min(Or f_max) Is detected.
However, the lower frequency f_min(Or f_max) Than the frequency f_min(Or f_max9) is considered that the detection point of the minimum value (or the maximum value) of the amplitude A becomes steeper as shown in FIG. 9 and the detection accuracy is improved.
[0059]
Therefore, in the eighth embodiment, the extreme value counter 24 detects the frequency f detected by the extreme value frequency detector 15._min(Or f_max) Is counted, and the distance x to the target 11 is calculated in consideration of the detection order m.
x = m · v / (2f_min) (19)
x = (m − ／) · v / (2f_max) (20)
Hereinafter, the description is omitted because it is the same as in the seventh embodiment.
According to the eighth embodiment, there is an effect that the accuracy of distance measurement can be improved as compared with the seventh embodiment.
[0060]
Embodiment 9 FIG.
FIG. 12 is a configuration diagram showing a distance measuring apparatus according to Embodiment 9 of the present invention. In the figure, the same reference numerals as in FIG. 8 denote the same or corresponding parts, and a description thereof will be omitted.
Reference numeral 25 denotes a Fourier transform of the detection result of the standing wave detection unit 14, and a reproduction frequency interval f_W(Fourier transformer) (frequency detecting means) for detecting.
[0061]
In the first to sixth embodiments, the extreme frequency detector 15 detects the frequency f of the swept signal in which the amplitude A of the standing wave detected by the standing wave detector 14 has a minimum value._i, F_{i + j}Is detected, and the reproduction frequency interval calculator 16 calculates the frequency f of the sweep signal._i, F_{i + j}From the reproduction frequency interval f_WHas been shown, but the Fourier transformer 25 performs a Fourier transform on the detection result of the standing wave detector 14 to obtain the reproduction frequency interval f._WMay be detected.
[0062]
Specifically, the Fourier transformer 25 performs a Fourier transform on the detection result of the standing wave detector 14 and analyzes the spectrum of the amplitude A of the standing wave, whereby a characteristic frequency appears, and the characteristic frequency is reproduced. Frequency interval f_WTherefore, the characteristic frequency is output to the distance calculator 23.
As a result, the reproduction frequency interval f can be quickly and accurately determined._WCan be detected, and even when a plurality of targets 11 are provided, the characteristic frequency of the standing wave by the plurality of targets can be obtained at the same time.
[0063]
【The invention's effect】
As described above, according to the present invention, the bandwidth of the sweep signal transmitted from the signal transmitting means is controlled in accordance with the distance calculated by the distance calculating means. The distance can be measured quickly.
[0064]
According to the present invention, since the sweep step width of the sweep signal transmitted from the signal transmission means is controlled in accordance with the distance calculated by the distance calculation means, high precision is achieved regardless of the distance to the target. Has the effect that the distance can be measured.
[0065]
According to the present invention, since the bandwidth of the sweep signal transmitted from the signal transmission means is controlled according to the distance calculated by the distance calculation means, and the sweep step width of the sweep signal is controlled, There is an effect that the distance can be measured quickly and accurately regardless of the distance to the target.
[0066]
According to the present invention, a difference frequency between a plurality of frequencies detected by the frequency detection unit is obtained, and the distance to the target is calculated by dividing the propagation speed of the sweep signal by the difference frequency. There is an effect that the distance to the target can be calculated with high accuracy without causing a complicated configuration.
[0067]
According to the present invention, when the stop position command indicating the stop position of the target is input, the bandwidth or the sweep step width of the sweep signal is controlled in consideration of the stop position. There is an effect that the distance can be measured with high accuracy.
[0068]
According to the present invention, the moving direction of the target is determined by comparing the currently calculated distance with the previously calculated distance, and the bandwidth or the sweep step width of the sweep signal is controlled in consideration of the moving direction. Therefore, even when the target is constantly moving, the distance can be measured quickly and accurately.
[0069]
According to the present invention, the movement position of the target is predicted by comparing the distance calculated this time with the distance calculated last time, and the bandwidth or the sweep step width of the sweep signal is controlled in consideration of the movement position. Therefore, even when the target is constantly moving, the distance can be measured quickly and accurately.
[0070]
According to this invention, when the frequency detecting means detects the frequency, the propagation speed of the sweep signal is divided by the frequency to calculate the distance to the target, so that the distance can be measured more quickly. There is an effect that can be done.
[0071]
According to the present invention, the detection order of the frequencies detected by the frequency detection means is counted, and the distance to the target is calculated in consideration of the detection order, so that the distance measurement accuracy can be further improved. There is an effect that can be.
[0072]
According to the present invention, the detection result of the standing wave detecting means is Fourier-transformed, and the difference frequency between the frequencies of the sweep signals having the extreme values is detected. There is an effect that measurement can be performed quickly and with high accuracy.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing a distance measuring device according to a first embodiment of the present invention.
FIG. 2 is an explanatory diagram showing the amplitude of a standing wave.
FIG. 3 is a configuration diagram showing a distance measuring device according to Embodiment 1 of the present invention.
FIG. 4 is a configuration diagram illustrating a distance measuring device according to a second embodiment of the present invention.
FIG. 5 is a configuration diagram showing a distance measuring device according to a third embodiment of the present invention.
FIG. 6 is a configuration diagram showing a distance measuring apparatus according to Embodiment 4 of the present invention.
FIG. 7 is a configuration diagram showing a distance measuring device according to Embodiment 5 of the present invention.
FIG. 8 is a configuration diagram showing a distance measuring device according to a seventh embodiment of the present invention.
FIG. 9 is an explanatory diagram showing the amplitude of a standing wave.
FIG. 10 is a configuration diagram showing a distance measuring device according to an eighth embodiment of the present invention.
FIG. 11 is an explanatory diagram illustrating a standing wave generated on a transmission path.
FIG. 12 is a configuration diagram showing a distance measuring apparatus according to Embodiment 9 of the present invention.
FIG. 13 is a configuration diagram showing a conventional distance measuring device.
FIG. 14 is an explanatory diagram showing a relationship between a distance to a target and a bandwidth of a sweep signal.
[Explanation of symbols]
11 target, 12 signal generator (signal transmitting means), 13 transmission line, 14 standing wave detector (standing wave detecting means), 15 extreme frequency detector (frequency detecting means), 16 reproduction frequency interval calculator (Distance calculation means), 17 distance calculator (distance calculation means), 18 bandwidth controller (control means), 19 extreme value counter, 20 step width controller (control means), 21 stop position commander, 22 distance comparison Unit (control means), 23 ° distance calculator (distance calculator), 24 ° extreme value counter (distance calculator), 25 ° Fourier transformer (frequency detector).

Claims (10)

Signal transmitting means for transmitting a sweep signal toward a target; standing wave detection for detecting the amplitude of a standing wave generated from the sweep signal transmitted from the signal transmitting means and the sweep signal reflected by the target Means, frequency detecting means for detecting the frequency of the sweep signal, in which the amplitude of the standing wave detected by the standing wave detecting means takes an extreme value, and based on the frequency of the sweep signal detected by the frequency detecting means. Distance calculating means for calculating the distance from the standing wave detecting means to the target, and controlling the bandwidth of the sweep signal transmitted from the signal transmitting means according to the distance calculated by the distance calculating means. A distance measuring device comprising control means. Signal transmitting means for transmitting a sweep signal toward a target; standing wave detection for detecting the amplitude of a standing wave generated from the sweep signal transmitted from the signal transmitting means and the sweep signal reflected by the target Means, frequency detecting means for detecting the frequency of the sweep signal, in which the amplitude of the standing wave detected by the standing wave detecting means takes an extreme value, and based on the frequency of the sweep signal detected by the frequency detecting means. A distance calculating means for calculating a distance from the standing wave detecting means to the target, and a sweep step width of a sweep signal transmitted from the signal transmitting means in accordance with the distance calculated by the distance calculating means. A distance measuring device comprising: Signal transmitting means for transmitting a sweep signal toward a target; standing wave detection for detecting the amplitude of a standing wave generated from the sweep signal transmitted from the signal transmitting means and the sweep signal reflected by the target Means, frequency detecting means for detecting the frequency of the sweep signal, in which the amplitude of the standing wave detected by the standing wave detecting means takes an extreme value, and based on the frequency of the sweep signal detected by the frequency detecting means. Distance calculating means for calculating the distance from the standing wave detecting means to the target, and controlling the bandwidth of the sweep signal transmitted from the signal transmitting means according to the distance calculated by the distance calculating means. And a control means for controlling a sweep step width of the sweep signal. The distance calculation means calculates a difference frequency between the plurality of frequencies detected by the frequency detection means, and calculates a distance to a target by dividing a propagation speed of the sweep signal by the difference frequency. The distance measuring device according to any one of claims 1 to 3. The control means, upon input of a stop position command indicating a stop position of the target, controls the bandwidth of the sweep signal or the sweep step width in consideration of the stop position. The distance measuring device according to claim 1. The control means compares the distance calculated this time by the distance calculation means with the previously calculated distance to determine the moving direction of the target, and in consideration of the moving direction, the bandwidth of the sweep signal or the sweep step width. The distance measuring device according to any one of claims 1 to 4, wherein the distance measuring device is controlled. The control means compares the distance calculated this time by the distance calculation means with the distance calculated last time to predict the moving position of the target, and in consideration of the moving position, the bandwidth of the sweep signal or the sweep step width. The distance measuring device according to any one of claims 1 to 4, wherein the distance measuring device is controlled. 4. The distance calculation means according to claim 1, wherein when the frequency detection means detects the frequency, the propagation speed of the sweep signal is divided by the frequency to calculate the distance to the target. 2. The distance measuring device according to claim 1. 9. The distance measuring apparatus according to claim 8, wherein the distance calculating means counts the order of detection of the frequency detected by the frequency detecting means, and calculates the distance to the target in consideration of the detected order. Instead of detecting the frequency of the sweep signal in which the amplitude of the standing wave takes an extreme value, the frequency detecting means performs a Fourier transform on the detection result of the standing wave detecting means, and calculates the frequency between each sweep signal in which the extreme value takes an extreme value. The distance measuring device according to any one of claims 1 to 3, wherein a difference frequency is detected.

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