JP4953502B2

JP4953502B2 - Two-dimensional scanning optical radar sensor

Info

Publication number: JP4953502B2
Application number: JP2000302760A
Authority: JP
Inventors: 白井　　稔人; 弘一蓬原
Original assignee: Nippon Signal Co Ltd
Current assignee: Nippon Signal Co Ltd
Priority date: 2000-10-02
Filing date: 2000-10-02
Publication date: 2012-06-13
Anticipated expiration: 2020-10-02
Also published as: JP2002107452A

Description

【０００１】
【発明の属する技術分野】
本発明は、物体監視を立体的な領域で行える２次元走査型光レーダセンサに関し、特に、センサ正常を確認しつつ物体監視が行える２次元走査型光レーダセンサに関する。
【０００２】
【従来の技術】
例えば、無人搬送車に関する国際安全規格では、進路上の物体を監視するための光レーダセンサは、進路上に横たわる人の発見等を配慮して、床面から所定高以下の位置で無人搬送車に取り付けるべきと規定されている。しかし、光ビームを２次元で走査して立体空間を監視する２次元走査型光レーダセンサを利用すれば、設置高が規定値以上であっても走査ビームを床面方向へも向けることができるので、実質的に上記規格の要件を満たすことができ、光レーダセンサの取付け自由度を高められる。
【０００３】
２次元走査型光レーダセンサとしては、例えば信学技法Ｖｏｌ．９９,Ｎｏ．５１６「２次元スキャニングレーダの開発」や、特開平１１−３０６４８５号公報等で開示されたもの等がある。
前者の２次元走査型光レーダセンサは、レーザダイオードから発せられた光ビームをポリゴンミラーで反射して空間へ放射し、走査ビームの光軸上に物体が存在すれば、物体からの反射光の受光で物体有りが通報される。そして、ポリゴンミラーは角錐台形状で各反射面の傾斜角を異ならせているので、ポリゴンミラーで反射して空間に放射される光ビームの走査が２次元になる。これにより、走査ビームの放射領域が光ビーム反射点を頂点とした立体となり、物体を立体的な領域で監視できる。
【０００４】
後者の２次元走査型光レーダセンサは、発光部からの光ビームを、ガルバノミラーで反射して所定領域内へ投光し、所定領域内に物体があれば、その反射光が受光手段で受光されて物体有りと判定される。ガルバノミラーは、特開平７−１７５００５号公報、特開平７−２１８８５７号公報等で公知のもので、互いに直交する回動軸でそれぞれ軸支された２つの可動部を駆動手段でそれぞれ独立に揺動駆動してミラーを傾動する。これにより、光ビームの走査が２次元となり走査ビームの放射領域が立体になる。
【０００５】
【発明が解決しようとする課題】
ところで、前記国際安全規格では、無人搬送車と人との衝突事故の重大性に鑑み、搭載する光レーダセンサは故障時に危険側に誤らないことが要求され、この場合、センサが正常であることの確認機能が必要である。しかし、上述したいずれの２次元走査型光レーダセンサも、センサの正常動作確認機能については示されていない。
【０００６】
尚、１次元走査型光レーダセンサについては、正常動作確認機能を備えたものが、例えば特開平１１−１４４１６１号公報等で公知である。
この１次元走査型光レーダセンサは、レーザダイオードから発せられた光ビームを回動軸が１つであるガルバノミラーで１次元に走査し、走査ビームの光軸上に物体が存在すれば、その反射光の受光により物体有りが通報される。そして、この１次元走査型光レーダセンサでは、物体監視領域の端部近傍に正常動作確認用の検査用反射体を備え、この検査用反射体からの反射光に基づいて正常動作確認手段によりセンサの正常動作を確認する構成である。
【０００７】
前記正常動作確認手段は、ガルバノミラーによる光ビームの放射方位が検査用反射体の存在する方位である時に、反射光の受光があれば正常、受光がなければ異常と判定する。そして、正常動作確認手段からセンサ正常の確認出力（論理値１）が発生している時に、不存在判定手段から物体無しの判定出力（論理値１）が発生すれば、物体無しの通報出力（論理値１）が生成される。これにより、センサ正常を確認しつつ物体の有無を監視している。
【０００８】
しかし、上述の１次元走査型光レーダセンサの正常動作確認手法を、上述の２次元走査型光レーダセンサに適用する場合、光ビームの鉛直方向と水平方向の各走査が構造的に不可分であるポリゴンミラーを走査ミラーとして用いる光レーダセンサには適用可能であるが、ガルバノミラーのように２つの方向の走査が独立に行われる走査ミラーを用いる光レーダセンサに、そのまま適用したのではセンサの正常確認ができない虞れがある。
【０００９】
即ち、図２４（Ａ）、（Ｂ）のように、上述の１次元走査型光レーダセンサの正常動作確認手法に基づいて、光ビームの走査領域Ａ（点線で囲まれた領域）内の監視領域Ｂ（実線で囲まれた領域）端部近傍に、反射体１，２を設け、これら反射体１，２からの反射光が周期的に受光されることで正常確認するとする。この場合、例えば一方の走査駆動機構の故障で光ビームの走査が、図の走査領域Ａ′で示すように１次元になっても、走査ビームは監視領域Ｂ端部近傍の反射体１，２に周期的に照射されるので、このような故障モードでは、反射体１，２からの反射光が正常時と同様に周期的に受光されて異常を通報できない。
【００１０】
本発明は上記問題点に着目してなされたもので、正常動作を確認しつつ物体監視ができる２次元走査型光レーダセンサを提供することを目的とする。また、２方向の光ビーム走査が独立に行われる走査方式であっても、正常動作を確認しつつ物体監視ができる２次元走査型光レーダセンサを提供することを目的とする。
【００１１】
【課題を解決するための手段】
このため、請求項１の発明の２次元走査型光レーダセンサは、光ビーム発生手段と、前記光ビーム発生手段からの光ビームを物体の監視領域を含んで２次元に走査可能な光ビーム走査手段と、該光ビーム走査手段から放射される走査ビームの走査空間からの反射光を受光する受光手段と、少なくとも前記受光手段の出力に基づき前記監視領域内の物体不在を判定する不存在判定手段と、少なくとも前記光ビーム発生手段、光ビーム走査手段及び受光手段の正常動作を確認する正常動作確認手段と、前記不存在判定手段の出力と前記正常動作確認手段の出力との論理積結果に基づいて安全情報を出力するゲート手段とを備ええ、前記正常動作確認手段が、前記光ビーム走査手段の走査ビーム放射方位が走査ビームの走査領域内に配置した検査用反射体の存在する方位であることを示す受光有無指示信号を発生する角度検出回路と、前記受光有無指示信号の発生期間における前記受光手段の出力の有無を確認し、受光出力があれば受光有りを示す出力を発生する反射有無確認回路と、前記受光有無指示信号の発生周期を確認し前記発生周期が所定周期のときに走査速度正常を示す出力を継続する期間確認回路と、前記反射有無確認回路の出力と前記期間確認回路の出力とを論理積演算するＡＮＤゲートとを備える構成とした。
【００１２】
かかる構成では、光ビーム発生手段から発生した光ビームを光ビーム走査手段により、物体の監視領域を含んで２次元に走査する。これにより、走査ビームは立体的な空間に放射され物体監視空間が立体的となる。不存在判定手段は、予め定めた監視領域内からの反射光に基づく受光手段の受光出力の有無により物体の不存在を判定する。正常動作確認手段は、光ビーム走査手段の走査ビーム放射方位が検査用反射体の存在する方位であることを示す受光有無指示信号を発生する角度検出回路と、受光有無指示信号の発生期間に受光出力があれば受光有りを示す出力を発生する反射有無確認回路と、受光有無指示信号の発生周期が所定周期のときに走査速度正常を示す出力を継続する期間確認回路と、反射有無確認回路の出力と期間確認回路の出力とを論理積演算するＡＮＤゲートとを備えて、少なくとも光ビーム発生手段、光ビーム走査手段及び受光手段の正常動作を確認する。不存在判定手段から物体不存在を示す判定出力が発生し、正常動作確認手段から動作正常を示す判定出力が発生した時にゲート手段から安全情報が出力される。
【００１４】
前記検査用反射体は、請求項２のように、センサ動作状態から得られる走査ビーム放射情報と前記受光手段の受光出力結果との対応関係が、想定される異常動作時と正常動作時とで異なるように配置するとよい。
かかる構成によれば、走査ビームの各方向の走査が独立に行われるような光ビーム走査手段を利用する場合にも、想定される異常動作時の走査ビーム放射情報と前記受光手段の受光出力結果との対応関係が正常動作時と異なるようになるので、正常動作の確認ができる。
【００１５】
請求項３のように、前記角度検出回路は、前記受光有無指示信号として前記光ビーム走査手段の走査ビーム放射方位が前記検査用反射体が存在する方位であること及び検査用反射体が存在しない方位であることを示す信号を発生し、前記反射有無確認回路は、前記受光有無指示信号の示す全ての方位について前記受光手段の出力の有無を確認する構成とするとよい。
【００１６】
前記正常動作確認手段は、請求項４のように、前記角度検出回路の受光有無指示信号に、センサから検査用反射体までの距離情報を付加する構成とするとよい。
【００１７】
請求項５のように、前記検査用反射体を、前記走査領域の隅部近傍に配置する構成とすれば、検査用反射体からの反射光が受光されることで、監視領域全体を走査ビームが走査されていることを確認できる。また、走査領域内に複数の監視領域がある場合に、監視領域毎に検査用反射体を配置する必要がない。
【００１８】
請求項６のように、前記検査用反射体を、前記監視領域外で当該監視領域の隅部近傍に配置する構成としてもよい。
請求項７のように、前記検査用反射体を、前記監視領域外縁に対する走査ビームの上下最大角及び左右最大角で示される方位近傍に配置する構成とすれば、監視領域が例えば球形状の場合でも好適である。
【００１９】
請求項８の発明では、移動体に２次元走査型光レーダセンサを搭載した場合において、前記移動体が予め定められた範囲内で移動する時に、前記検査用反射体を、前記監視領域内に少なくとも１つ以上存在するよう配置する構成とした。
かかる構成では、走査ビームが監視すべき領域に放射されていることを確認しつつ移動体が移動できるようになる。
【００２０】
請求項９のように、前記検査用反射体を、前記移動体の移動方向に沿って連続して存在するよう配置する構成とすれば、移動体の移動中でも正常動作の確認が常時同一の走査ビーム放射範囲で実行できるようになる。
前記不存在判定手段は、請求項１０のように、前記受光手段の受光出力から前記監視領域内の前記検査用反射体からの反射光による受光出力を除外して物体の有無を判定する構成とした。
【００２１】
前記検査用反射体を、請求項１１のように入射する走査ビームの光強度周波数を変調する構成としてもよく、また、請求項１２のように入射する走査ビームの波長を変調する構成としてもよい。
かかる構成によれば、検査用反射体からの反射光と物体からの反射光の識別が容易になる。
【００２２】
請求項１３のように、前記検査用反射体を情報表示手段に用いる構成とすれば、検査用反射体により表示情報を伝達できるようになる。
【００２３】
【発明の実施の形態】
以下、本発明の実施形態を図面に基づいて説明する。
図１に、本発明に係る２次元走査型光レーダセンサの第１実施形態のブロック構成図を示す。
図１において、発光素子１１は、発光素子駆動回路１２により駆動されて光ビームを発生する。走査ミラー１３は、発光素子１１からの光ビームを反射し走査ビームとして物体監視空間に放射する。走査ミラー１３は、例えば後述する半導体ガルバノミラーであり、第１駆動回路１４により回動軸１３ａを中心に周期的に揺動駆動され、第２駆動回路１５により前記回動軸１３ａと直交する回動軸１３ｂを中心に周期的に揺動される。走査ビームは、走査ミラー１３の揺動に伴って図中の左右及び上下方向に、監視領域Ｂ（図の実線で囲まれた領域）を含む走査領域Ａ（図の点線で囲まれた領域）を２次元に走査する。これにより、走査ビームは、走査ミラー１３の光ビーム反射点を頂点とした図中２点鎖線で示す角錐状の立体空間に放射され、立体的な空間で物体監視ができる。前記監視領域Ｂ外で走査領域Ａ内の監視領域四隅近傍に、正常動作確認用の検査用反射体ｍ１〜ｍ４を設ける。前記角錐状の走査ビーム放射空間内からの反射光は、受光素子１６で受光され、電気信号に変換されて受光回路１７で増幅・検波等の処理後、受光出力Ｒ１として不存在判定手段１８及び正常動作確認手段１９へ入力される。ゲート手段としてのＡＮＤゲート２０は、不存在判定手段１８及び正常動作確認手段１９の各出力Ｓ、Ｎを論理積演算して演算結果を出力Ｚとして出力する。ここで、前記発光素子１１と発光素子駆動回路１２で光ビーム発生手段を構成し、前記走査ミラー１３、第１及び第２駆動回路１４，１５で光ビーム走査手段を構成し、受光素子１６及び受光回路１７で受光手段を構成する。
【００２４】
前記走査ミラー１３として用いる半導体ガルバノミラーを図２に示す。半導体ガルバノミラーは、特開平７−１７５００５号公報、特開平７−２１８８５７号公報等で公知であり、その構成及び動作原理についてここでは簡単に説明する。
図２は、特開平７−１７５００５号公報に記載の構成例である。中央部の可動板３１表面に蒸着金属膜等で形成したミラー３２を有する。前記可動板３１を第１のトーションバー３３Ａで可動枠３４内に支持し、可動枠３４を更に第２のトーションバー３３Ｂで固定枠３５内に支持する。可動板３１及び可動枠３４にはそれぞれ駆動コイル３６Ａ及び３６Ｂが設けられ、これら駆動コイル３６Ａ，３６Ｂ両端の１対の電極端子３７Ａ，３７Ｂに駆動電流を供給する。駆動コイル３６Ａ，３６Ｂに、図示しない永久磁石等の静磁界発生手段により静磁界を作用させている。
【００２５】
動作は、可動板３１及び可動枠３４の両端部の平面に沿って各駆動コイル３６Ａ，３６Ｂを横切る方向に静磁界を作用させた状態で、駆動コイル３６Ａ，３６Ｂに電流を流すと、可動板３１及び可動枠３４の両端部に、フレミングの左手の法則に従った方向に電磁力が作用し、可動板３１及び可動枠３４が回動する。可動板３１及び可動枠３４が回動すると各トーションバー３３Ａ，３３Ｂ（図１の回動軸１３ａ，１３ｂに相当する）が捩じられ、発生するトーションバー３３Ａ，３３Ｂの各ばね反力と可動板３１及び可動枠３４に作用する各電磁力とが釣り合う位置まで可動板３１及び可動枠３４が回動する。前記電磁力は各駆動コイル３６Ａ，３６Ｂに流れる電流に比例するので、可動板３１及び可動枠３４のそれぞれの変位角は各駆動コイル３６Ａ，３６Ｂに流れる電流に比例する。従って、各駆動コイル３６Ａ，３６Ｂに流す電流を制御することで、可動板３１及び可動枠３４、即ちミラー３２の変位角を２次元で制御できる。予め駆動コイル３６Ａ，３６Ｂの電流量と可動板３１及び可動枠３４の変位角との関係を求めておけば、前記電流量からミラー３２の変位角の情報を得ることができる。
【００２６】
従って、本実施形態では、前記駆動コイル３６Ａ、３６Ｂにそれぞれ駆動電流を供給する各駆動回路１４，１５から、駆動電流に基づいたミラーの変位角、即ち、走査ビームの放射方位を示す情報信号ｐ１，ｐ２を、不存在判定手段１８及び正常動作確認手段１９に入力している。
尚、特開平７−２１８８５７号公報で示されるように、可動板の変位検出用の検出コイルを設ければ、この検出コイルでミラー変位角を検出できるので、変位検出用コイルの出力を図１の情報信号ｐ１，ｐ２の代わりに用いれば、変位検出コイルの出力からミラーの走査状態が正常か否かを直接監視できるようになる。
【００２７】
前記不存在判定手段１８は、監視領域Ｂに対応する走査ビーム方位を記憶しており、両駆動回路１４，１５の信号ｐ１，ｐ２の示す走査ビーム方位が記憶情報に一致する時に、受光回路１７の受光出力Ｒ１の有無を判定することで監視領域Ｂに対応する監視空間内における物体の存在／不在を判定し、物体不在の時にＳ＝１、物体存在の時にＳ＝０を出力する。
【００２８】
前記正常動作確認手段１９は、前記検査用反射体ｍ１〜ｍ４が存在する方位を記憶しており、後述するように両駆動回路１４，１５の信号ｐ１，ｐ２の示す走査ビーム放射方位が記憶情報に一致する時に、受光出力の有無を判定し、センサの正常動作を確認して正常と判定した時にＮ＝１、異常と判定した時Ｎ＝０を出力する。
【００２９】
図３に、本実施形態の正常動作確認手段１９の回路構成を示す。
図３において、本実施形態の正常動作確認手段１９は、角度検出回路１９Ａ、反射有無確認回路１９Ｂ、期間確認回路１９Ｃ、及びＡＮＤゲート１９Ｄを備える。
前記角度検出回路１９Ａは、予め配置された検査用反射体ｍ１〜ｍ４のそれぞれの方位（θ₁，ψ₁）〜（θ₄，ψ₄）を記憶しており、入力する信号ｐ１，ｐ２が示す走査ビーム方位（θ，ψ）情報が記憶方位情報と一致した時に、受光の有無を判定すべき時であることを指示する指示情報として受光有無指示信号Ｓｒ＝１を出力する。前記方位（θ₁，ψ₁）〜（θ₄，ψ₄）以外では受光有無指示信号Ｓｒ＝０とする。
【００３０】
反射有無確認回路１９Ｂは、受光有無指示信号Ｓｒ＝１の期間で受光出力Ｒ１の有無を確認し、受光出力Ｒ１が入力すれば出力ＮＳ＝１を継続し、受光出力Ｒ１が入力しなければＮＳ＝０とする。
期間確認回路１９Ｃは、信号Ｓｒ＝１の発生周期、即ち、走査ビームの走査速度を確認し、信号Ｓｒ＝１の発生周期が所定周期であれば走査速度正常として出力ＮＴ＝１を継続し、所定周期でなければ走査速度異常としてＮＴ＝０とする。
【００３１】
ＡＮＤゲート１９Ｄは、出力ＮＳ＝１とＮＴ＝１が共に入力する時にセンサが正常であることを示す出力Ｎ＝１を発生する。
尚、前記走査ビーム方位（θ，ψ）は、図４で示すように、監視領域Ｂの中心Ｏ（走査領域Ａの中心でもある）を原点とした、それぞれ左右方向（ｘ方向）、上下方向（ｙ方向）の光ビーム方位とする。
【００３２】
ここで、ポリゴンミラーは勿論、ガルバノミラーのように各方向の走査が独立に行われる走査ミラーを用いた場合でも、２次元走査型光レーダセンサの正常動作確認ができる検査用反射体の配置原理について説明する。
正常動作確認手段１９は、走査ビームの走査領域Ａ内に予め配置される検査用反射体の方位情報（反射体存在範囲）を記憶し、更に、走査ビームの走査領域Ａ内の検査用反射体の存在しない領域の方位情報（空隙範囲）を記憶し、それらの方位情報と入力する受光出力の有無をつきあわせて正常か否かを判定する。即ち、正常動作確認手段１９に、走査領域Ａにおける方位（走査ビーム方位）と受光回路１７の出力論理値（受光ありで論理値１、受光なしで論理値０）の関係を予め記憶させ、ビーム走査時に実際に得られた方位−論理値の結果が、記憶情報と一致している時を正常動作と判定し、不一致の時を異常と判定する。
【００３３】
前記空隙範囲は、検査用反射体の存在しない範囲であって、物体不在時に受光なしとなる範囲であればよく、監視領域Ｂを含んでも構わない。ただし、監視領域Ｂを含めた場合、監視領域Ｂ内に物体が存在すると、物体からの反射光が受光されるので、物体不存在判定手段１８が物体を検出するだけでなく、正常動作確認手段１９が方位−論理値の結果が記憶情報と不一致になり異常判定してしまう。従って、空隙範囲は、走査領域Ａ内であって且つ監視領域Ｂ外の範囲とすることが望ましい。
【００３４】
尚、想定の異常状態において、論理値１（受光あり）となるべき時に論理値０（受光なし）に誤るように検査用反射体を構成できるならば、正常動作確認手段１９は、走査ビームの走査領域Ａ内の検査用反射体の方位情報（反射体存在範囲）のみを記憶し、その方位情報の時の受光出力の論理値のみ確認する構成でよい。
【００３５】
半導体ガルバノミラーの場合、ミラー可動部の故障等で走査ビームの走査が前述の図２４の走査領域Ａ′のような１次元になる異常状態が想定される。この場合、駆動回路の出力状態とミラー可動部の実際の動きが異なる。このため、図２４のように監視領域Ｂ端部近傍に単に棒状の検査用反射体１，２を配置する構成では、走査が１次元（走査領域Ａ′）となる走査異常時でも監視領域Ｂ端部近傍で常に反射光が得られるため、この異常時に得られる方位−論理値の結果と正常時に得られる方位−論理値の結果とが同じとなり、異常を検出できない。従って、２次元走査型光レーダセンサの正常動作を確実に確認するには、想定される走査異常時に得られる方位−論理値の結果が、正常時に実際に得られる方位−論理値の結果と必ず異なるように検査用反射体を構成する必要がある。
【００３６】
図５にそのような検査用反射体の構成例を示し、２次元走査型光レーダセンサの正常動作確認原理を説明する。
図５において、検査用反射体１を、反射体１ａと反射体１ｂとに分割し、両反射体１ａと１ｂとの間に空隙３を設け、正常時には、受光出力が論理値１となる区間（反射体存在範囲）と論理値０となる区間（空隙範囲）が存在するように構成する。
【００３７】
かかる構成によれば、前述のような走査が１次元となる走査異常時は、監視領域Ｂ端部近傍で常に反射光が得られ走査ビームの方位情報ｐ１，ｐ２が空隙範囲（正常時に論理値０になる区間）を示す時でも受光出力が論理値１となるので、走査異常時に得られる方位−論理値の結果が正常時と異なり、異常が検出できるので、２次元走査型光レーダセンサの場合でも正常動作確認が可能となる。また、発光素子１１等の故障で走査ビームが投光されない異常では、方位情報ｐ１，ｐ２が反射体存在範囲（正常時に論理値１になる区間）を示す時でも受光出力が論理値０となるので、走査異常時に得られる方位−論理値の結果が正常時と異なり、異常が検出できる。
【００３８】
図１の第１実施形態における検査用反射体１ｍ〜４ｍの配置構成は、図５の構成原理に基づいたものである。
図１のように、監視領域Ｂの四隅近傍に検査用反射体１ｍ〜４ｍを配置する構成では、想定される図２４のような異常時には、走査ビームの方位情報ｐ１，ｐ２が検査用反射体１ｍ〜４ｍの存在方位を示す時（受光出力Ｒ１が論理値１となるべき時）に受光出力Ｒ１は論理値０となるので、走査ビームの方位情報ｐ１，ｐ２が検査用反射体１ｍ〜４ｍの存在方位を示す時の受光出力Ｒ１の有無を検出すれば正常確認を行える。
【００３９】
尚、監視領域Ｂの外側で検査用反射体からの反射光が得られれば、少なくとも監視領域Ｂ全面を走査していることを確認できるので、検査用反射体１ｍ〜４ｍは図１の監視領域Ｂの上端及び下端から突出するよう配置することが望ましい。
次に、第１実施形態の正常確認動作について、図６のタイムチャートを参照しながら説明する。
【００４０】
走査ミラー１３を揺動駆動する各駆動回路１４，１５から、走査ビームの方位（θ，ψ）を示す情報信号ｐ１，ｐ２が正常動作確認手段１９内の角度検出回路１９Ａに入力する。角度検出回路１９Ａは、検査用反射体ｍ１〜ｍ４のそれぞれの方位（θ₁，ψ₁）〜（θ₄，ψ₄）を記憶している。角度検出回路１９Ａは、入力する情報信号ｐ１，ｐ２の示す方位が記憶情報と一致しているか否かを判定し、一致する方位情報（検査用反射体存在方位情報）が入力する毎に、図６に示すように受光の有無確認期間であることを示す情報をＳｒ＝１として反射有無確認回路１９Ｂ及び期間確認回路１９Ｃへ出力する。反射有無確認回路１９Ｂは、Ｓｒ＝１が入力している期間で受光出力Ｒ１が入力したか否かを判定し、受光出力Ｒ１＝１が入力するとＮＳ＝１を発生する。図６のようにＳｒ＝１の時にＲ１＝１が入力する関係が維持されていれば、反射有無確認回路１９ＢからＮＳ＝１が継続する。また、期間確認回路１９Ｃは、走査ミラー１３の走査速度が正常で、信号Ｓｒ＝１が所定間隔で発生していればＮＴ＝１を継続する。従って、検査用反射体ｍ１〜ｍ４の存在方位（θ₁，ψ₁）〜（θ₄，ψ₄）に走査ビームが放射された時に反射光が受光され（ＮＳ＝１）、且つ、走査ミラー１３の走査速度が正常（ＮＴ＝１）であれば、正常動作確認手段１９からセンサ正常を示すＮ＝１が継続して出力される。一方、例えば、図６中、点線ｆ１で示すように、Ｓｒ＝１の時に受光出力Ｒ１＝０であれば、ＮＳ＝０となり正常動作確認手段１９の出力はＮ＝０となる。
【００４１】
また、不存在判定手段１８は、Ｓｒ＝０の期間中で自身が記憶している監視領域の方位情報が入力する時に受光出力Ｒ１＝０であれば、物体なしとして出力Ｓ＝１を継続して発生する。一方、例えば、図６中、点線ｆ２で示すように、監視領域に相当するビーム方位で受光出力Ｒ１＝１になった場合は、物体からの反射と判断し不存在判定手段１８の出力は物体ありを示すＳ＝０となる。
【００４２】
図１のＡＮＤゲート２０は、不存在判定手段１８からＳ＝１が発生し、正常動作確認手段１９からＮ＝１が発生した時のみＺ＝１の出力を発生し、安全を通報する。
以上のように、第１実施形態によれば、走査が１次元となるような想定される異常状態では、走査ミラー１３の駆動系から得られる走査ビーム方位情報が検査用反射体存在方位である時に反射光が受光されず、正常時に得られるべき論理値と実際に得られた論理値が異なって異常を検出できる。また、光レーダセンサの取り付け不良等により本来放射すべき領域に光ビームが放射されていない場合も、検査用反射体ｍ１〜ｍ４の反射光が存在すべき放射方位において少なくとも一部の反射光は受光されなくなるので、異常が通報される。
【００４３】
また、角度検出回路１９Ａに、監視領域Ｂを除いた全ての走査領域について、方位−論理値の関係を記憶させ、方位情報ｐ１，ｐ２に基づいて、走査ビーム方位が論理値１（受光あり）となるべき方位（反射体存在範囲）であること及び走査ビーム方位が論理値０（受光なし）となるべき方位（空隙範囲）であることを、信号Ｓｒにより反射有無確認回路１９Ｂへ指示し、反射有無確認回路１９Ｂで監視領域Ｂを除いた走査領域全てについて受光の有無を確認する構成とすれば、例えば、故障等で光ビームが検査用反射体ｍ１とｍ２の間を往復する状況になった場合でも、受光出力がＲ１＝０となるべき時にＲ１＝１となったことを検出してＮＳ＝０を出力することができ、異常を検出できるので、正常動作確認機能の信頼性をより一層向上できる。
【００４４】
また、図７に点線で示すように走査領域Ａの検査用反射体ｍ１〜ｍ４以外の全ての領域を領域Ｂ′として監視領域Ｂに含めれば、領域Ｂ′から反射光があった場合には不存在判定手段１８側が物体からの反射光と見なして出力Ｓ＝０となるので、角度検出回路１９Ａ及び反射有無確認回路１９Ｂが、検査用反射体ｍ１〜ｍ４の存在方位についてだけ方位−論理値の関係を監視する構成でも危険を通報できるので、上述と同様にセンサの信頼性をより一層向上できる。
【００４５】
尚、例えば、反射光の受光強度に対して閾値を設け、受光強度が閾値以上の時に受光有りと判定する構成とすると共に、検査用反射体ｍ１〜ｍ４の反射率をその反射光受光強度が前記閾値を少し超える程度に調整しておけば、発光素子１１の劣化等による光ビーム強度の低下や、受光素子１６の劣化による光−電気変換効率低下等による反射光受光強度の低下等の不具合を早期に検出できる利点がある。検査用反射体ｍ１〜ｍ４の反射率は、反射面の材質や色等によって調節可能である。
【００４６】
また、図１において、不存在判定手段１８及び正常動作確認手段１９へ入力されている信号ｐ１，ｐ２を、不存在判定手段１８及び正常動作確認手段１９のいずれか一方へ入力し、他方へは信号ｐ１，ｐ２が入力される手段を介して同等の情報信号を伝える構成としてもよい。例えば、受光出力Ｒ１を不存在判定手段１８へ入力し、不存在判定手段１８を介して受光出力Ｒ１と同等の情報信号を正常動作確認手段１９へ伝達する構成とすれば、少なくとも不存在判定手段１８が出力Ｒ１を受信していることが確認でき、更に、不存在判定手段１８の出力Ｒ１の処理動作が正常か否かの確認も可能である。
【００４７】
次に、本発明の第２実施形態として光レーダセンサが測距機能を有する場合について説明する。
本実施形態では、図１の点線で示すように、発光素子駆動回路１２から発光パルスと同期して出力される発光状態を示す信号Ｋを、それぞれ不存在判定手段１８及び正常動作確認手段１９に入力する。正常動作確認手段１９は、図３の構成に加えて図８のディレー回路１９Ｅを備え、該ディレー回路１９Ｅに、前記信号Ｋを入力する構成である。物体までの距離は、光ビームの発光と反射光の受光の時間差や発光ビームと受光ビームの位相差等により算出できることは公知であり、ここでは距離算出方法の詳細は省略する。光レーダセンサから検査用反射体ｍ１〜ｍ４までの距離はそれぞれ既知であるので、信号Ｋが入力してから各検査用反射体ｍ１〜ｍ４からの反射光が受光されるまでの各時間ΔＴは予め算出できる。前記ΔＴは、各検査用反射体ｍ１〜ｍ４までの距離に応じて異なる。各検査用反射体ｍ１〜ｍ４毎の時間ΔＴの情報はディレー回路１９Ｅに記憶されている。また、本実施形態では、角度検出回路１９Ａからの信号Ｓｒは、各検査用反射体ｍ１〜ｍ４に対応する走査ビーム方位の識別情報を含んでいるものとする。
【００４８】
従って、ディレー回路１９Ｅは、図８に示すように、角度検出回路１９Ａから出力された信号Ｓｒが受光有無の確認期間であることを示す時（Ｓｒ＝１の時）、信号Ｓｒに含まれた方位情報に基づいて対応する検査用反射体についてのディレー時間ΔＴを選択し、信号Ｋの入力から選択ディレー時間ΔＴ遅延させて信号Ｓｒ′＝１を出力する。
【００４９】
これにより、図９に示すように、Ｓｒ′＝１の時にＲ１＝１が入力すれば、反射有無確認回路１９Ｂは、検査用反射体ｍ１〜ｍ４による受光出力Ｒ１と判断してＮＳ＝１を継続する。一方、例えば、図９中、点線ｆ１で示すように、Ｓｒ′＝１の時に受光出力Ｒ１＝０であれば、ＮＳ＝０となる。また、Ｓｒ′＝０の期間における監視領域Ｂの走査範囲において受光出力Ｒ１＝０であれば、不存在判定手段１８は物体なしとして出力Ｓ＝１を継続して発生するが、図９中、点線ｆ２で示すように、受光出力Ｒ１＝１になった場合は、不存在判定手段１８の出力は物体ありを示すＳ＝０となる。
【００５０】
かかる構成では、第１実施形態と同様の効果に加えて、受光素子１６や受光回路１７の動作遅れが増大した場合、信号Ｓｒ′と受光出力Ｒ１の発生時期に時間軸上のずれが生じるので、センサ異常として通報できる利点がある。また、光レーダセンサからの監視距離を規定して監視領域Ｂを設定できるので、所望の空間領域を設定して物体監視が可能となる。
【００５１】
次に、図１０〜図１３に上述の第１及び第２実施形態に適用可能な検査用反射体の別の配置例について説明する。
図１と同様に監視領域Ｂの四隅近傍に配置する場合、図１０のように配置してもよい。
また、図１１のように、監視領域Ｂ外縁において、第１駆動回路１４による回動軸１３ａ回りの方位角θ（走査ビームの方位角）について、最大角θｍａｘ、最小角θｍｉｎを同定し、第２駆動回路１５による回動軸１３ｂ回りの方位角ψについて、最大角ψｍａｘ、最小角ψｍｉｎを同定し、方位角（θｍａｘ、ψｍａｘ）、（θｍｉｎ、ψｍａｘ）、（θｍａｘ、ψｍｉｎ）、（θｍｉｎ、ψｍｉｎ）方向近傍にそれぞれ検査用反射体ｍ１〜ｍ４を配置してもよい。かかる配置方法は、特に監視領域Ｂが例えば球形等の場合に好適である。
【００５２】
また、図１２に示すように、一部の検査用反射体ｍを床面に配置してもよい。この場合、検査用反射体ｍとしては、例えば床面に貼り付けた点字マット等が考えられる。尚、検査用反射体の床面等への配置については、本出願人による特開２０００−１６２３０６号公報等で詳述されている。
図２のガルバノミラーのように、回動軸１３ａと１３ｂの回動動作が独立している場合、一部の検査用反射体を省略することが可能である。
【００５３】
例えば、図１３に示すように、回動軸１３ａ回りの方位角θについて、最大角θｍａｘの反射体ｍ３と最小角θｍｉｎの反射体ｍ４を選択し、回動軸１３ｂ回りの方位角ψについて、最大角ψｍａｘの反射体ｍ２（ｍ１でもよい）と最小角ψｍｉｎの反射体ｍ３を選ぶ。この時に選ばれなかった反射体を省くことができる。図１３では、検査用反射体ｍ１（又はｍ２）を省くことができる。
【００５４】
かかる配置方法を適用すると、図１や図１０の場合、どちらか一方の対角線の検査用反射体、即ち、検査用反射体ｍ１とｍ４或いはｍ２とｍ３を省くことができる。
また、図２のようなガルバノミラーは、構造上、揺動角が上下及び左右のどちらも対称と考えられるので、方位角±θについて絶対値│θ│が最大の検査用反射体と、方位角±ψについて絶対値│ψ│が最大の検査用反射体を選び、他を省略することができる。図１や図１０の配置構成に適用すると、検査用反射体ｍ１〜ｍ４のいずれか１つ設ければよい。
【００５５】
尚、走査ミラー１３にポリゴンミラーを用いた場合、光ビームの走査正常確認は回転動作の正常確認に置き換えられるので、検査用反射体はいずれか１つあればよい。また、走査領域Ａ四隅近傍に配置すれば、走査領域Ａを走査していることが確認されるので、走査領域Ａ内の監視領域Ｂを走査していることも同時に確認できる。しかも、走査領域Ａ内に複数の監視領域Ｂがあっても各監視領域Ｂ毎に検査用反射体を配置する必要がなくなる利点がある。
【００５６】
次に、２次元走査型光レーダセンサを移動体に搭載した場合について説明する。
光レーダセンサを移動体に搭載した場合、センサの正常動作確認と共に、監視すべき領域に走査ビームが放射されていることの確認を行う必要がある。正常動作の確認は、前述した正常動作確認用の検査用反射体をセンサに固定すれば、走査ミラーと反射体との相対位置は一定であり、前述と同様にして移動体の移動に関係なく正常動作の確認を行える（移動体の走行範囲にセンサに起因する制限はない）。更に、走査ビームが監視すべき領域に放射されていることの確認を行う場合、監視領域内に放射領域確認用の検査用反射体を配置し、この検査用反射体からの反射光の有無を確認すればよい。尚、放射領域確認用検査用反射体は、移動体の走行により危険状態の発生が想定される領域外縁部（センサが監視すべき監視領域に相当する領域）の付近に配置することが好ましい。
【００５７】
図１４に、光レーダセンサを移動体に搭載した場合の検査用反射体の配置例を示す。（Ａ）は上面図、（Ｂ）は側面図である。
図１４において、移動体１００に取付けた２次元走査型光レーダセンサ１０１には、走査ミラー（図示せず）の前方に例えば図１と同様の配置で正常動作確認用の検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬが取付けられている。光レーダセンサ１０１は、これら反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬの反射光に基づいて、前述と同様にして正常動作確認手段１９でセンサ１０１の正常動作の確認を行う。
【００５８】
また、移動体１００の移動空間の外縁近傍四隅に、図示のように走行路１０２に沿って一定の間隔を設けて放射領域確認用の検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｕ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌが配置してある。尚、上記の各検査用反射体は、再帰反射性を有するものとする。
放射領域確認用の検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｕ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌの同定は、信号ｐ１，ｐ２と受光出力Ｒ１から得られる画像内での反射体位置パターンや反射体の方位（及び距離）情報を、移動体の現在位置と予め記憶されている反射体位置から導出される反射体の予想位置パターンや予想方位（及び距離）データと比較して行えばよい。
【００５９】
図１５（Ａ）〜（Ｃ）は、移動体１００が図１４中の矢印方向に移動した場合の光レーダセンサ１０１の放射方位情報及び受光出力Ｒ１に基づく画像の変化を示している。点線で囲まれた領域が走査ビームの走査領域Ａを示す。
図１５（Ａ）は、図１４の位置での画像を示し、検査用反射体ａ２Ｕ、ａ２Ｌ、ｂ２Ｕ、ｂ２Ｌとａ３Ｕ、ａ３Ｌ、ｂ３Ｕ、ｂ３Ｌが検出されている。検査用反射体ａ４Ｕ、ａ４Ｌ、ｂ４Ｕ、ｂ４Ｌは遠方であるので検出されていない。移動体１００の移動に従って、図１５（Ｂ）のように、検査用反射体ａ２Ｕ、ａ２Ｌ、ｂ２Ｕ、ｂ２Ｌが走査領域外となって画像から消え、検査用反射体ａ３Ｕ、ａ３Ｌ、ｂ３Ｕ、ｂ３Ｌのみが検出されるようになる。更に移動すると、図１５（Ｃ）のように検査用反射体ａ４Ｕ、ａ４Ｌ、ｂ４Ｕ、ｂ４Ｌが検出され始める。このように、移動体１００が走行路１０２を移動する際に、検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｕ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌを検出したことで、走査ビームが本来の監視すべき領域に放射されていることを確認できる。
【００６０】
図１４の構成で正常動作確認用検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを省くことが可能である。この場合、走査ビームの走査の確認は、最外縁に検出される放射領域確認用の検査用反射体で囲まれる範囲に限られる。即ち、図１５（Ａ）や（Ｃ）では、検査用反射体ａ２Ｕ、ａ２Ｌ、ｂ２Ｕ、ｂ２Ｌや検査用反射体ａ３Ｕ、ａ３Ｌ、ｂ３Ｕ、ｂ３Ｌで囲まれる範囲で走査ビームの走査確認が行われ、図１５（Ｂ）では検査用反射体ａ３Ｕ、ａ３Ｌ、ｂ３Ｕ、ｂ３Ｌで囲まれる範囲で行われる。
【００６１】
従って、正常動作確認用検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを省いた場合、これら検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを用いた場合と略同等の走査範囲で正常動作確認ができるのは、放射領域確認用の各検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｌ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌがフレームアウトする直前、即ち、図１５の画像の四隅に各検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｕ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌが位置した時点であり、連続的ではなく移動体の移動に伴って周期的となる。
【００６２】
正常動作確認用検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを省いて、検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを用いた場合と略同等の走査範囲で連続的に正常動作確認を行うには、放射領域確認用の各検査用反射体ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｌ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌを、例えば図１６のように構成すればよい。
【００６３】
図１６（Ａ）、（Ｂ）のように、検査用反射体ａＵ，ａＬ，ｂＵ，ｂＬを、移動体１００の移動空間の外縁近傍四隅に走行路１０２に沿って連続的に配置する。
かかる構成とすれば、図１７（Ａ）〜（Ｃ）で示すように、移動体１００が移動しても検査用反射体ａＵ，ａＬ，ｂＵ，ｂＬで囲まれる範囲が変化せず、検査用反射体ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬを設けた場合と同等の走査範囲で、連続的に正常動作確認が行える。図１７中のｈ２，ｈ３，ｈ４は、図１６の位置ｈ２，ｈ３，ｈ４と対応している。
【００６４】
尚、２次元走査型光レーダセンサを搭載する移動体としては、図示した走行車両に限らずロボットアーム等でもよい。また、走査ミラーにガルバノミラーのように互いの走査方向のミラー回動動作が独立したものを採用した場合は、図１３で説明したようにして検査用反射体の一部を省くことが可能である。
図１４、図１６の場合、監視領域Ｂ内に放射領域確認用検査用反射体が含まれるので、不存在判定手段１８は、前記検査用反射体からの受光出力Ｒ１を除いて物体の有無を判定する必要がある。このため、不存在判定手段１８に、前述した正常動作確認手段１９内の角度検出回路１９Ａと同様の回路を備え、信号Ｓｒと同様の指示信号を用い、この信号Ｓｒ＝１が入力した時の受光出力を除いて物体の有無を判定するようにする。
【００６５】
図１８及び図１９に、検査用反射体存在領域を監視領域から除く場合において、光レーダセンサが測距機能を有さない場合と有する場合の違いを示す。図１８は測距機能を有さない場合、図１９は測距機能を有する場合である。両図の（Ａ）は上面図、（Ｂ）は側面図を示す。図中の点線は走査ビームの走査領域Ａである。
【００６６】
測距機能を有さない場合、監視領域Ｂと非監視領域Ｃ（検査用反射体からの反射光が受光される領域）は図示のようになり、図のように物体１０５が検査用反射体方位に存在すると、物体１０５の反射光と検査用反射体の反射光を識別できない虞れがあるが、測距機能を有する場合は、図１９ように非監視領域Ｃが検査用反射体周囲に限定されるので、物体１０５からの反射光とその後方の検査用反射体からの反射光を識別することが可能である。尚、上述の領域区分けの方法は、これまで述べてきた各実施形態においても同様に適用できることは言うまでもない。
【００６７】
図１８のような場合でも、図２０及び図２１に示す構成の検査用反射体とすれば、検査用反射体からの反射光と物体からの反射光を識別可能である。
図２０（Ａ）、（Ｂ）は、反射光の光強度周波数を変調する構成の可動型検査用反射体の構成例である。
図２０（Ａ）の検査用反射体２００は、図示しない駆動手段により回動する軸２０１にミラー２０２を取付ける構成である。ミラー２０２が再帰反射性は低いものとすれば、入射光ビームは、検査用反射体２００の回動角に応じた方位に反射される。従って、検査用反射体２００からの反射光は、検査用反射体２００の回動周波数で変調されて光レーダセンサの受光素子で受光される。その変調情報は受光出力Ｒ１に含まれて正常動作確認手段１９の反射有無確認回路１９Ｂへ入力される。反射有無確認回路１９Ｂは、前記変調された受光出力Ｒ１が入力する時に、検査用反射体２００からの反射光と見なすことができ、物体からの反射光と識別できる。例えば、受光信号が特定の周波数で変調されていることを、その周波数を通過させる帯域通過フィルタを設けることで検出できる。
【００６８】
また、図２０（Ｂ）の検査用反射体２１０は、軸２１１回りに揺動可能にミラー２１２を軸支すると共に、ミラー２１２にバネ２１３を連結し、ミラー２１２に外部から振動エネルギーを供給して揺動させる構成である。特に、揺動周波数を検査用反射体２１０の質量とバネ定数で定まる共振周波数とすると、大きく揺動させることができる。かかる構成では、例えば光レーダセンサに音波発生手段を設け、センサからの音波により検査用反射体２１０に振動エネルギーを供給すれば、検査用反射体２１０は、自身に駆動手段を持つ必要がなく無電源化できる利点がある。
【００６９】
図２１は、反射光の波長を変調する構成の波長変換型検査用反射体の例である。
図２１の波長変換型検査用反射体２２０は、ミラー２２１の前面に波長変換層２２２を設ける構成で、入射光ビームを異なる波長の反射光に変換する。本実施形態では、例えば青色の入射光ビームを赤色の光ビームに変換して反射する。このような波長変換技術は、間宮他：自動制御学会ヒューマン・インターフェース部会第１３回ヒューマン・インターフェース・シンポジウム論文集、１９９６、ｐ．４９３−５００等で公知である。
【００７０】
波長変換型検査用反射体２２０を用いる場合、例えば赤色光ビームのみを透過し青色光ビームを遮光する特性の光学フィルタを備えた受光素子と、該受光素子からの出力により受光出力を発生する受光回路とを、図１の構成の光レーダセンサに、別途設けるようにする。
これにより、検査用反射体２２０で波長変換された赤色光ビームの反射光は光学フィルタ付き受光素子のみで受光され、受光回路からは検査用反射体２２０の反射光が存在する時のみ受光出力が発生する。従って、この受光出力は検査用反射体の反射光の存在を示す情報となり、この受光出力が発生した時に正常動作確認手段１９の受光有無確認回路１９Ｂで、受光出力Ｒ１の有無を判定することで正常動作の確認が可能である。
【００７１】
図２０及び図２１に示すような検査用反射体を用いれば、検査用反射体の反射光と物体の反射光の識別を容易にでき、図１８のような状態でも測距機能を設けることなく両者の識別が可能となる。また、検査用反射体の方位を示す信号ｐ１，ｐ２を省くことが可能となる。
放射領域確認用検査用反射体を、情報表示手段として用いることも可能である。図２２にその例を示す。図２２は、例えば移動体１００の走行情報を表示させる例を示し、（Ａ）は上面図、（Ｂ）は側面図である。尚、図１４と同一の構成要素には同一符号を付す。
【００７２】
図２２において、検査用反射体ａ〜ｃを、例えば、走行路１０２上に設置し、移動体１００に搭載した光レーダセンサ１０１の光ビームの放射領域確認用と同時に情報表示用に用いる。情報は、無情報である基本形の反射体形状（反射特性）を情報に対応して予め定めた形状（反射特性）に変更することで表示する。例えば、本実施形態では、検査用反射体ｃを基本形として無情報とし、基本形をバーコード状に変形して情報を表示するようにしている。検査用反射体ａ〜ｃの形状（反射特性）は、信号Ｒ１に基づいて抽出され、予め記憶されている反射持性−情報の対応関係に基づき、前記信号Ｒ１の出力状態から情報を解読する。
【００７３】
図２３（Ａ）〜（Ｃ）は、移動体１００が図２２中の矢印方向に移動した場合の光レーダセンサ１０１の受光出力に基づく画像の変化を示している。
（Ａ）の画像は、既に検査用反射体ａの表示情報の解読・実行が完了し、検査用反射体ｂに近づいている状態を示す。この画像において、検査用反射体ｂは点線で囲まれており、これは光ビームの放射領域確認用の検査用反射体として認識されていることを表し、検査用反射体ｂにより監視領域に光ビームが放射されていることが確認される。検査用反射体ｂが例えば「走行速度」情報を表示しているとし、検査用反射体ｂの表示情報は、（Ｂ）のように画像上の横線Ｉに検査用反射体ｂが重なった時に解読され実行され、検査用反射体ｂの示す「走行速度」情報に基づき移動体１００は走行する。（Ｃ）では、無情報の検査用反射体ｃが確認され、監視領域に光ビームが放射されていることだけの確認が行われる。
【００７４】
かかる構成とすれば、例えば鉄道車両に適用した場合に、検査用反射体を例えば枕木上に配置し、検査用反射体により情報を車両に提供することが可能となる。提供する情報としては、例えば、「制限速度」、「線路勾配」、「踏切までの距離」等の固定情報の他に、上述のバーコード形状を可変にできる構成とすれば、「前方の信号現示」、「ポイント開通方向」等の可変情報も表示可能となる。また、停止位置情報を表示すれば、定点停止制御に用いることも可能になる。
【００７５】
尚、検査用反射体の同定及び情報の読み取りは、本実施形態のような画像による方法に限定されるものではなく、上述のように方位・距離情報等によっても可能である。また、検査用反射体の配置位置は走行路上に限られないことは言うまでもない。更に、複数の検査用反射体の組み合わせで情報を表示しても構わない。
【００７６】
【発明の効果】
以上説明したように請求項１の発明によれば、走査ビームを２次元的に走査して物体監視を立体的空間で行える２次元走査型光レーダセンサで、正常動作の確認を行いつつ物体監視が行えるので、無人搬送車等への光レーダセンサ取付けの自由度を高められる。
【００７７】
請求項２の発明によれば、上記効果に加えてガルバノミラーのような走査ビームの各方向の走査が独立に行われる光ビーム走査手段を利用する場合にも、正常動作の確認を確実にできる。
請求項３の発明によれば、正常動作の確認機能の信頼性を高められる。
請求項４の発明によれば、検査用反射体の存在位置が方位だけでなくセンサからの距離でも定められるので、検査用反射体と物体とが重なるような場合でも両者の識別が可能になり、物体監視機能の信頼性を高められる。
【００７８】
請求項５の発明によれば、走査領域内に複数の監視領域がある場合に、監視領域毎に検査用反射体を配置する必要がなくなる。
請求項７の発明によれば、監視領域が例えば球形状の場合でも好適である。
請求項８、９の発明によれば、走査ビームが監視すべき領域に放射されていることを確認しつつ移動体が移動できる。
【００７９】
請求項１０の発明によれば、移動体搭載時の物体監視機能の信頼性を高められる。
請求項１１、１２の発明によれば、検査用反射体からの反射光と物体からの反射光の識別が容易となるので、正常動作確認機能及び物体監視機能の信頼性をより一層高められる。
【００８０】
請求項１３の発明によれば、検査用反射体を正常動作確認用としてだけでなく、情報の伝達にも利用できる。
【図面の簡単な説明】
【図１】本発明に係る２次元走査型光レーダセンサの第１実施形態の概略構成図
【図２】同上実施形態に適用する半導体ガルバノミラーの要部構成図
【図３】正常動作確認手段の構成図
【図４】走査ビーム方位の説明図
【図５】２次元走査型光レーダセンサの検査用反射体の配置原理の説明図
【図６】第１実施形態の正常動作確認手段の動作を説明するタイムチャート
【図７】監視領域の設定例を示す図
【図８】測距機能を備える本発明の第２実施形態の正常動作確認手段の要部構成図
【図９】第２実施形態の正常動作確認手段の動作を説明するタイムチャート
【図１０】検査用反射体の別の配置例を示す図
【図１１】検査用反射体の別の配置例を示す図
【図１２】検査用反射体の別の配置例を示す図
【図１３】検査用反射体の別の配置例を示す図
【図１４】移動体搭載時の検査用反射体の構成例を示し、（Ａ）は上面図、（Ｂ）は側面図
【図１５】図１４のセンサで検出した移動体進行方向画面の変化状態を示す図
【図１６】移動体搭載時の検査用反射体の別の構成例を示し、（Ａ）は上面図、（Ｂ）は側面図
【図１７】図１６のセンサで検出した移動体進行方向画面の変化状態を示す図
【図１８】測距機能がない場合における監視領域内の検査用反射体位置を除く説明図で、（Ａ）は上面図、（Ｂ）は側面図
【図１９】測距機能がある場合における監視領域内の検査用反射体位置を除く説明図で、（Ａ）は上面図、（Ｂ）は側面図
【図２０】走査ビームの光強度周波数を変調する構成の検査用反射体の構成例を示す図
【図２１】走査ビームの波長を変調する構成の検査用反射体の構成例を示す図
【図２２】情報表示機能を設けた検査用反射体の構成例を示す図で、（Ａ）は上面図、（Ｂ）は側面図
【図２３】図２２のセンサで検出した移動体進行方向画面の変化状態を示す図
【図２４】１次元走査型光レーダセンサの正常動作確認手法を２次元走査型光レーダセンサに適用した場合の問題点を説明する図
【符号の説明】
１１発光素子
１２発光素子駆動回路
１３走査ミラー
１４第１駆動回路
１５第２駆動回路
１６受光素子
１７受光回路
１８不存在判定手段
１９正常動作確認手段
２０ＡＮＤゲート
ｍ１〜ｍ４検査用反射体
ＥａＵ，ＥｂＵ，ＥａＬ，ＥｂＬ検査用反射体
ａ１Ｕ〜ａ４Ｕ，ａ１Ｌ〜ａ４Ｕ，ｂ１Ｕ〜ｂ４Ｕ，ｂ１Ｌ〜ｂ４Ｌ検査用反射体
ａ，ｂ，ｃ検査用反射体
２００，２１０，２２０検査用反射体、
Ａ走査領域
Ｂ監視領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a two-dimensional scanning optical radar sensor capable of monitoring an object in a three-dimensional region, and more particularly to a two-dimensional scanning optical radar sensor capable of monitoring an object while confirming normality of the sensor.
[0002]
[Prior art]
For example, in the international safety standards for automated guided vehicles, the optical radar sensor for monitoring objects on the route is designed to be used at a position below a predetermined height from the floor in consideration of finding people lying on the route. It is prescribed that it should be attached to. However, if a two-dimensional scanning optical radar sensor that scans a light beam in two dimensions and monitors a three-dimensional space is used, the scanning beam can be directed toward the floor even if the installation height is equal to or higher than a specified value. Therefore, the requirements of the above standard can be substantially satisfied, and the degree of freedom in mounting the optical radar sensor can be increased.
[0003]
As the two-dimensional scanning optical radar sensor, for example, the scientific technique Vol. 99, no. 516 “Development of two-dimensional scanning radar”, Japanese Patent Application Laid-Open No. 11-306485, and the like.
The former two-dimensional scanning optical radar sensor reflects a light beam emitted from a laser diode by a polygon mirror and radiates it to the space. If an object exists on the optical axis of the scanning beam, the reflected light from the object is reflected. The presence of an object is notified by light reception. Since the polygon mirror has a truncated pyramid shape and the inclination angle of each reflecting surface is different, the scanning of the light beam reflected by the polygon mirror and emitted to the space becomes two-dimensional. Thereby, the radiation area of the scanning beam becomes a solid with the light beam reflection point as a vertex, and the object can be monitored in the three-dimensional area.
[0004]
In the latter two-dimensional scanning optical radar sensor, the light beam from the light emitting unit is reflected by a galvanometer mirror and projected into a predetermined area. If there is an object in the predetermined area, the reflected light is received by the light receiving means. It is determined that there is an object. Galvano mirrors are well known in Japanese Patent Application Laid-Open Nos. 7-175005 and 7-218857, and each of the two movable parts supported by rotating shafts orthogonal to each other is independently rocked by driving means. The mirror is tilted by driving. Thereby, the scanning of the light beam becomes two-dimensional, and the radiation area of the scanning beam becomes three-dimensional.
[0005]
[Problems to be solved by the invention]
By the way, in the international safety standard, in view of the seriousness of the collision accident between the automatic guided vehicle and the person, it is required that the mounted optical radar sensor should not be mistaken for the dangerous side at the time of failure. In this case, the sensor is normal. A confirmation function is required. However, none of the two-dimensional scanning optical radar sensors described above show a function for confirming the normal operation of the sensor.
[0006]
A one-dimensional scanning optical radar sensor having a normal operation confirmation function is known, for example, in Japanese Patent Application Laid-Open No. 11-144161.
This one-dimensional scanning optical radar sensor scans a light beam emitted from a laser diode in a one-dimensional manner with a galvanometer mirror having one rotation axis, and if an object exists on the optical axis of the scanning beam, The presence of an object is reported when the reflected light is received. In this one-dimensional scanning optical radar sensor, an inspection reflector for confirming normal operation is provided in the vicinity of the end of the object monitoring area, and the sensor is detected by the normal operation confirmation means based on the reflected light from the reflector for inspection. It is the structure which confirms the normal operation of.
[0007]
The normal operation confirmation means determines that the reflected light is normal if the radiation direction of the light beam from the galvano mirror is the direction in which the inspection reflector exists, and abnormal if the reflected light is not received. Then, if a sensor output (logical value 1) is output from the non-existence determining means when a normal sensor confirmation output (logical value 1) is generated from the normal operation checking means, an object non-notification output ( A logical value 1) is generated. Thereby, the presence / absence of an object is monitored while the normality of the sensor is confirmed.
[0008]
However, when the above-described normal operation confirmation method for the one-dimensional scanning optical radar sensor is applied to the above-described two-dimensional scanning optical radar sensor, the vertical scanning and the horizontal scanning of the light beam are structurally inseparable. Although it can be applied to an optical radar sensor that uses a polygon mirror as a scanning mirror, if it is applied as it is to an optical radar sensor that uses a scanning mirror in which scanning in two directions is performed independently, such as a galvano mirror, the sensor is normal. There is a possibility that it cannot be confirmed.
[0009]
That is, as shown in FIGS. 24A and 24B, based on the above-described normal operation confirmation method of the one-dimensional scanning optical radar sensor, the light beam scanning area A (area surrounded by a dotted line) is monitored. It is assumed that reflectors 1 and 2 are provided in the vicinity of the end of region B (region surrounded by a solid line), and that reflected light from these reflectors 1 and 2 is periodically received to confirm normality. In this case, for example, even if the scanning of the light beam becomes one-dimensional as indicated by the scanning region A ′ in the figure due to a failure of one scanning drive mechanism, the scanning beam is reflected by the reflectors 1 and 2 near the end of the monitoring region B. Therefore, in such a failure mode, the reflected light from the reflectors 1 and 2 is periodically received as in the normal state, and an abnormality cannot be reported.
[0010]
The present invention has been made paying attention to the above problems, and an object thereof is to provide a two-dimensional scanning optical radar sensor capable of monitoring an object while confirming normal operation. It is another object of the present invention to provide a two-dimensional scanning optical radar sensor that can monitor an object while confirming normal operation even in a scanning method in which light beam scanning in two directions is performed independently.
[0011]
[Means for Solving the Problems]
  For this reason, the two-dimensional scanning optical radar sensor according to the first aspect of the present invention is a light beam scanning device capable of two-dimensionally scanning the light beam from the light beam generating means and the object monitoring region. Means, light receiving means for receiving reflected light from the scanning space of the scanning beam emitted from the light beam scanning means, and non-existence determining means for determining the absence of an object in the monitoring region based on at least the output of the light receiving means And at least normal operation confirmation means for confirming normal operation of the light beam generation means, light beam scanning means, and light receiving means, and a logical product result of the output of the absence determination means and the output of the normal operation confirmation means And gate means for outputting safety information.The angle detection is performed so that the normal operation confirmation unit generates a light reception presence / absence instruction signal indicating that the scanning beam radiation direction of the light beam scanning unit is the direction in which the inspection reflector disposed in the scanning region of the scanning beam exists. A circuit, a reflection presence / absence confirmation circuit for confirming the presence / absence of an output of the light receiving means during the generation period of the light reception presence / absence instruction signal, and generating an output indicating the presence of light reception if there is a light reception output, and a generation period of the light reception presence / absence indication signal And a period confirmation circuit that continues output indicating normal scanning speed when the generation period is a predetermined period, and an AND gate that performs an AND operation on the output of the reflection confirmation circuit and the output of the period confirmation circuit It was set as the structure provided.
[0012]
  In such a configuration, the light beam generated from the light beam generating unit is scanned two-dimensionally by the light beam scanning unit including the monitoring region of the object. As a result, the scanning beam is emitted into a three-dimensional space, and the object monitoring space becomes three-dimensional. The absence determination means determines the absence of an object based on the presence or absence of a light reception output of the light reception means based on reflected light from a predetermined monitoring area. Normal operation confirmation meansAn angle detection circuit for generating a light reception presence / absence instruction signal indicating that the scanning beam radiation direction of the light beam scanning means is the direction in which the reflector for inspection exists, and light reception is present if there is a light reception output during the generation period of the light reception presence / absence instruction signal A reflection presence / absence confirmation circuit that generates an output indicating a light reception presence / absence indication signal, a period confirmation circuit that continues output indicating a normal scanning speed when the generation period of the light reception presence / absence indication signal is a predetermined period, An AND gate that performs an AND operation on the output, andAt least normal operation of the light beam generating means, the light beam scanning means, and the light receiving means is confirmed. When the determination output indicating the absence of the object is generated from the absence determination means and the determination output indicating the normal operation is generated from the normal operation confirmation means, the safety information is output from the gate means.
[0014]
  The inspection reflector is a claim.2As described above, the correspondence relationship between the scanning beam radiation information obtained from the sensor operation state and the light reception output result of the light receiving means may be arranged to be different between an assumed abnormal operation and a normal operation.
  According to such a configuration, even when using a light beam scanning unit in which scanning in each direction of the scanning beam is performed independently, the scanning beam radiation information at the time of an abnormal operation and the light reception output result of the light receiving unit are assumed. Is different from that during normal operation, so normal operation can be confirmed.
[0015]
  According to a third aspect of the present invention, in the angle detection circuit, as the light reception presence / absence instruction signal, the scanning beam radiation direction of the light beam scanning means is an orientation in which the inspection reflector exists and there is no inspection reflector. It is preferable that a signal indicating the direction is generated, and the reflection presence / absence confirmation circuit is configured to confirm the presence / absence of the output of the light receiving means for all the directions indicated by the light reception presence / absence instruction signal.
[0016]
  The normal operation confirmation means4like,It may be configured to add distance information from the sensor to the inspection reflector to the light reception presence / absence instruction signal of the angle detection circuit.
[0017]
  ContractClaim5As described above, if the inspection reflector is arranged in the vicinity of the corner of the scanning area, the scanning beam is scanned over the entire monitoring area by receiving the reflected light from the inspection reflector. Can be confirmed. Further, when there are a plurality of monitoring areas in the scanning area, it is not necessary to arrange an inspection reflector for each monitoring area.
[0018]
  Claim6As described above, the inspection reflector may be arranged outside the monitoring area and in the vicinity of the corner of the monitoring area.
  Claim7As described above, if the inspection reflector is arranged in the vicinity of the azimuth indicated by the maximum vertical and horizontal angles of the scanning beam with respect to the outer edge of the monitoring area, it is preferable even when the monitoring area is, for example, spherical. is there.
[0019]
  Claim8According to the invention, when the two-dimensional scanning optical radar sensor is mounted on the moving body, when the moving body moves within a predetermined range, at least one inspection reflector is provided in the monitoring area. It was set as the structure arrange | positioned so that it might exist above.
  With such a configuration, the moving body can move while confirming that the scanning beam is emitted to the region to be monitored.
[0020]
  Claim9Thus, if the inspection reflector is arranged so as to be continuously present along the moving direction of the moving body, the normal scanning operation can always be confirmed even when the moving body is moving. Can be executed with
  The non-existence determining means is a claim.10As described above, the presence / absence of an object is determined by excluding the light reception output by the reflected light from the inspection reflector in the monitoring region from the light reception output of the light receiving means.
[0021]
  The inspection reflector,11The light intensity frequency of the incident scanning beam may be modulated as in12In this way, the wavelength of the incident scanning beam may be modulated.
  According to this configuration, it becomes easy to distinguish the reflected light from the inspection reflector and the reflected light from the object.
[0022]
  Claim13As described above, if the inspection reflector is used for the information display means, the display information can be transmitted by the inspection reflector.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a first embodiment of a two-dimensional scanning optical radar sensor according to the present invention.
In FIG. 1, a light emitting element 11 is driven by a light emitting element driving circuit 12 to generate a light beam. The scanning mirror 13 reflects the light beam from the light emitting element 11 and radiates it to the object monitoring space as a scanning beam. The scanning mirror 13 is, for example, a semiconductor galvanometer mirror, which will be described later. The scanning mirror 13 is periodically oscillated by the first drive circuit 14 around the rotation shaft 13a, and is rotated by the second drive circuit 15 perpendicular to the rotation shaft 13a. It is periodically oscillated around the moving shaft 13b. The scanning beam is scanned in a scanning area A (area surrounded by a dotted line in the figure) including a monitoring area B (area surrounded by a solid line in the figure) in the horizontal and vertical directions in the figure as the scanning mirror 13 swings. Are scanned two-dimensionally. As a result, the scanning beam is radiated to a pyramid-shaped three-dimensional space indicated by a two-dot chain line in the drawing with the light beam reflection point of the scanning mirror 13 as a vertex, and the object can be monitored in the three-dimensional space. In the vicinity of the four corners of the monitoring area in the scanning area A outside the monitoring area B, inspection reflectors m1 to m4 for confirming normal operation are provided. The reflected light from the pyramid-shaped scanning beam radiation space is received by the light receiving element 16, converted into an electric signal, processed by the light receiving circuit 17 such as amplification and detection, and then as non-existence determining means 18 as a light receiving output R1. Input to the normal operation confirmation means 19. The AND gate 20 as the gate means performs an AND operation on the outputs S and N of the absence determination means 18 and the normal operation confirmation means 19 and outputs the calculation result as an output Z. Here, the light emitting element 11 and the light emitting element driving circuit 12 constitute a light beam generating means, and the scanning mirror 13 and the first and second driving circuits 14 and 15 constitute a light beam scanning means, and the light receiving element 16 and The light receiving circuit 17 constitutes a light receiving means.
[0024]
A semiconductor galvanometer mirror used as the scanning mirror 13 is shown in FIG. Semiconductor galvanometer mirrors are known in Japanese Patent Application Laid-Open Nos. 7-175005 and 7-218857, and their configuration and operation principle will be briefly described here.
FIG. 2 shows a configuration example described in JP-A-7-175005. A mirror 32 formed of a deposited metal film or the like is provided on the surface of the movable plate 31 at the center. The movable plate 31 is supported in the movable frame 34 by the first torsion bar 33A, and the movable frame 34 is further supported in the fixed frame 35 by the second torsion bar 33B. The movable plate 31 and the movable frame 34 are provided with drive coils 36A and 36B, respectively, and a drive current is supplied to a pair of electrode terminals 37A and 37B at both ends of the drive coils 36A and 36B. A static magnetic field is applied to the drive coils 36A and 36B by static magnetic field generating means such as a permanent magnet (not shown).
[0025]
In operation, when a static magnetic field is applied in a direction across the drive coils 36A and 36B along the planes of both ends of the movable plate 31 and the movable frame 34, a current is passed through the drive coils 36A and 36B. Electromagnetic force acts on both ends of 31 and the movable frame 34 in a direction in accordance with Fleming's left-hand rule, and the movable plate 31 and the movable frame 34 rotate. When the movable plate 31 and the movable frame 34 are rotated, the torsion bars 33A and 33B (corresponding to the rotation shafts 13a and 13b in FIG. 1) are twisted, and the generated spring reaction force of the torsion bars 33A and 33B is movable. The movable plate 31 and the movable frame 34 rotate to a position where the electromagnetic forces acting on the plate 31 and the movable frame 34 are balanced. Since the electromagnetic force is proportional to the current flowing through the drive coils 36A and 36B, the displacement angles of the movable plate 31 and the movable frame 34 are proportional to the current flowing through the drive coils 36A and 36B. Therefore, the displacement angle of the movable plate 31 and the movable frame 34, that is, the mirror 32 can be controlled two-dimensionally by controlling the current flowing through the drive coils 36A and 36B. If the relationship between the current amounts of the drive coils 36A and 36B and the displacement angles of the movable plate 31 and the movable frame 34 is obtained in advance, information on the displacement angle of the mirror 32 can be obtained from the current amounts.
[0026]
Therefore, in the present embodiment, the information signals p1 indicating the mirror displacement angle based on the drive current, that is, the radiation direction of the scanning beam, from the drive circuits 14 and 15 that supply the drive current to the drive coils 36A and 36B, respectively. , P2 are input to the absence determination means 18 and the normal operation confirmation means 19.
As shown in Japanese Patent Laid-Open No. 7-218857, if a detection coil for detecting the displacement of the movable plate is provided, the mirror displacement angle can be detected by this detection coil, so the output of the displacement detection coil is shown in FIG. If the information signals p1 and p2 are used, it is possible to directly monitor whether or not the scanning state of the mirror is normal from the output of the displacement detection coil.
[0027]
The absence determination means 18 stores the scanning beam azimuth corresponding to the monitoring region B, and when the scanning beam azimuth indicated by the signals p1 and p2 of both the drive circuits 14 and 15 matches the stored information, the light receiving circuit 17 The presence / absence of the object in the monitoring space corresponding to the monitoring area B is determined by determining the presence or absence of the received light output R1, and S = 1 is output when no object is present, and S = 0 is output when the object is present.
[0028]
The normal operation confirming means 19 stores the direction in which the inspection reflectors m1 to m4 exist, and the scanning beam radiation direction indicated by the signals p1 and p2 of the drive circuits 14 and 15 is stored information as will be described later. Is determined, the presence / absence of a light reception output is determined, N = 1 is output when the normal operation of the sensor is confirmed and it is determined that the sensor is normal, and N = 0 is output when it is determined that the sensor is abnormal.
[0029]
FIG. 3 shows a circuit configuration of the normal operation check means 19 of the present embodiment.
In FIG. 3, the normal operation confirmation means 19 of this embodiment includes an angle detection circuit 19A, a reflection presence / absence confirmation circuit 19B, a period confirmation circuit 19C, and an AND gate 19D.
The angle detection circuit 19 </ b> A is configured so that each of the azimuths (θ₁, Ψ₁) To (θ_Four, Ψ_Four), And when the scanning beam azimuth (θ, ψ) information indicated by the input signals p1 and p2 coincides with the stored azimuth information, the instruction information indicates that it is time to determine whether or not to receive light. A light reception presence / absence instruction signal Sr = 1 is output. The orientation (θ₁, Ψ₁) To (θ_Four, Ψ_FourIn other cases, the light reception presence / absence instruction signal Sr = 0.
[0030]
The reflection presence / absence confirmation circuit 19B confirms the presence / absence of the light reception output R1 in the period of the light reception presence / absence instruction signal Sr = 1. If the light reception output R1 is input, the output NS = 1 is continued, and if the light reception output R1 is not input, NS = 0.
The period confirmation circuit 19C confirms the generation period of the signal Sr = 1, that is, the scanning speed of the scanning beam. If the generation period of the signal Sr = 1 is a predetermined period, the scanning speed is normal and the output NT = 1 is continued. If it is not a predetermined period, NT = 0 is set as an abnormal scanning speed.
[0031]
The AND gate 19D generates an output N = 1 indicating that the sensor is normal when both outputs NS = 1 and NT = 1 are input.
As shown in FIG. 4, the scanning beam azimuth (θ, ψ) has the center O of the monitoring area B (also the center of the scanning area A) as the origin, and the horizontal direction (x direction) and the vertical direction, respectively. The light beam azimuth is (y direction).
[0032]
Here, even when a scanning mirror that scans in each direction independently is used, such as a galvanometer mirror as well as a polygon mirror, the principle of arrangement of the inspection reflector that can confirm the normal operation of the two-dimensional scanning optical radar sensor is used. Will be described.
The normal operation confirmation means 19 stores azimuth information (reflector existence range) of the inspection reflector arranged in advance in the scanning beam scanning region A, and further, the inspection reflector in the scanning beam scanning region A. The azimuth information (gap range) of the area where no light is present is stored, and the directional information and the presence / absence of the received light reception output are combined to determine whether it is normal. That is, the normal operation confirmation means 19 stores in advance the relationship between the azimuth (scanning beam azimuth) in the scanning region A and the output logical value of the light receiving circuit 17 (logical value 1 with light reception, logical value 0 without light reception). When the result of the azimuth-logical value actually obtained at the time of scanning matches the stored information, it is determined as normal operation, and when it does not match, it is determined as abnormal.
[0033]
The gap range may be a range in which there is no inspection reflector and no light is received when no object is present, and may include the monitoring region B. However, when the monitoring area B is included, if an object is present in the monitoring area B, the reflected light from the object is received. Therefore, the object absence determination means 18 not only detects the object but also normal operation confirmation means. 19 is an azimuth-logical value result which is inconsistent with the stored information and is judged abnormal. Therefore, it is desirable that the gap range be within the scanning area A and outside the monitoring area B.
[0034]
If the inspection reflector can be configured so as to be mistaken for a logical value of 0 (no light reception) when it should be a logical value of 1 (light reception) in an assumed abnormal state, the normal operation confirmation means 19 can detect the scanning beam. Only the azimuth information (reflector existence range) of the inspection reflector in the scanning area A may be stored, and only the logical value of the light reception output at the time of the azimuth information may be confirmed.
[0035]
In the case of a semiconductor galvanometer mirror, an abnormal state is assumed in which the scanning beam scan is one-dimensional like the scanning region A ′ of FIG. In this case, the output state of the drive circuit and the actual movement of the mirror movable part are different. For this reason, in the configuration in which the bar-shaped inspection reflectors 1 and 2 are arranged in the vicinity of the end of the monitoring area B as shown in FIG. 24, the monitoring area B even when scanning is abnormal in one dimension (scanning area A ′). Since reflected light is always obtained in the vicinity of the end, the result of the azimuth-logical value obtained at the time of abnormality is the same as the result of the azimuth-logical value obtained at the time of normality, and the abnormality cannot be detected. Therefore, in order to confirm the normal operation of the two-dimensional scanning optical radar sensor with certainty, the result of the azimuth-logical value obtained at the time of the assumed scanning abnormality must be the same as the result of the azimuth-logical value actually obtained at the normal time. It is necessary to configure the reflector for inspection differently.
[0036]
FIG. 5 shows an example of the configuration of such an inspection reflector, and the normal operation confirmation principle of the two-dimensional scanning optical radar sensor will be described.
In FIG. 5, the inspection reflector 1 is divided into a reflector 1a and a reflector 1b, and a gap 3 is provided between the reflectors 1a and 1b. (Reflector existence range) and a section (gap range) having a logical value of 0 exist.
[0037]
According to such a configuration, in the case of abnormal scanning in which the scanning is one-dimensional as described above, reflected light is always obtained near the end of the monitoring region B, and the azimuth information p1 and p2 of the scanning beam is the gap range (logical value in the normal state). Since the received light output is a logical value 1 even when indicating a period of 0), the azimuth-logical value result obtained at the time of scanning abnormality is different from that at normal time, and an abnormality can be detected. Therefore, the two-dimensional scanning optical radar sensor Even in this case, normal operation can be confirmed. In the case where the scanning beam is not projected due to a failure of the light emitting element 11 or the like, the light reception output becomes a logical value 0 even when the azimuth information p1 and p2 indicate the reflector existing range (a section where the logical value is 1 at normal time). Therefore, the azimuth-logical value obtained when the scanning is abnormal is different from the normal result, and the abnormality can be detected.
[0038]
The arrangement configuration of the inspection reflectors 1m to 4m in the first embodiment of FIG. 1 is based on the configuration principle of FIG.
In the configuration in which the inspection reflectors 1m to 4m are arranged near the four corners of the monitoring region B as shown in FIG. Since the received light output R1 becomes a logical value 0 when the existing azimuth of 1m to 4m is indicated (when the received light output R1 should be a logical value 1), the azimuth information p1 and p2 of the scanning beam are the inspection reflectors 1m to 4m. The normality can be confirmed by detecting the presence or absence of the light receiving output R1 when indicating the presence direction of the light.
[0039]
If the reflected light from the inspection reflector is obtained outside the monitoring region B, it can be confirmed that at least the entire monitoring region B is scanned, so that the inspection reflectors 1m to 4m are shown in FIG. It is desirable to arrange so as to protrude from the upper and lower ends of B.
Next, the normal confirmation operation of the first embodiment will be described with reference to the time chart of FIG.
[0040]
Information signals p1 and p2 indicating the azimuth (θ, ψ) of the scanning beam are input to the angle detection circuit 19A in the normal operation confirmation means 19 from the respective drive circuits 14 and 15 that drive the scanning mirror 13 to swing. The angle detection circuit 19A is configured so that each of the azimuths (θ₁, Ψ₁) To (θ_Four, Ψ_Four) Is remembered. The angle detection circuit 19A determines whether or not the orientations indicated by the input information signals p1 and p2 match the stored information. Each time the matching orientation information (inspection reflector presence orientation information) is input, the angle detection circuit 19A As shown in FIG. 6, information indicating that there is a light reception presence / absence confirmation period is output as Sr = 1 to the reflection presence / absence confirmation circuit 19 </ b> B and the period confirmation circuit 19 </ b> C. The reflection presence / absence confirmation circuit 19B determines whether or not the light reception output R1 is input during the period in which Sr = 1 is input. When the light reception output R1 = 1 is input, NS = 1 is generated. If the relationship of inputting R1 = 1 when Sr = 1 is maintained as shown in FIG. 6, NS = 1 continues from the reflection presence / absence confirmation circuit 19B. The period confirmation circuit 19C continues NT = 1 if the scanning speed of the scanning mirror 13 is normal and the signal Sr = 1 is generated at a predetermined interval. Accordingly, the existing orientation (θ of the reflectors m1 to m4 for inspection)₁, Ψ₁) To (θ_Four, Ψ_Four), The reflected light is received when the scanning beam is emitted (NS = 1) and the scanning speed of the scanning mirror 13 is normal (NT = 1). = 1 is continuously output. On the other hand, for example, as shown by a dotted line f1 in FIG. 6, if the light reception output R1 = 0 when Sr = 1, NS = 0 and the output of the normal operation confirmation means 19 becomes N = 0.
[0041]
Further, if the light reception output R1 = 0 when the azimuth information of the monitoring area stored therein is input during the period of Sr = 0, the absence determination unit 18 continues the output S = 1 as no object. Occur. On the other hand, for example, as indicated by a dotted line f2 in FIG. 6, when the light reception output R1 = 1 in the beam direction corresponding to the monitoring region, it is determined that the light is reflected from the object and the output of the non-existence determining means 18 is the object. S = 0 indicating presence.
[0042]
The AND gate 20 of FIG. 1 generates an output of Z = 1 only when S = 1 occurs from the non-existence determining means 18 and N = 1 occurs from the normal operation confirmation means 19, and reports safety.
As described above, according to the first embodiment, the scanning beam direction information obtained from the drive system of the scanning mirror 13 is the inspection reflector existence direction in the abnormal state that is assumed to be one-dimensional scanning. Sometimes the reflected light is not received, and the abnormality can be detected because the logical value that should be obtained in the normal state differs from the logical value that is actually obtained. Further, even when the light beam is not radiated to the area that should originally be emitted due to poor mounting of the optical radar sensor or the like, at least a part of the reflected light in the radiation azimuth in which the reflected light of the inspection reflectors m1 to m4 should exist. Abnormality is reported because no light is received.
[0043]
Further, the angle detection circuit 19A stores the azimuth-logical value relationship for all the scanning regions except the monitoring region B, and the scanning beam azimuth has a logical value 1 (with light reception) based on the azimuth information p1 and p2. Instructing the reflection presence / absence confirmation circuit 19B by the signal Sr that the direction should be (reflector existence range) and that the scanning beam direction should be the logical value 0 (no light reception) is the direction (gap range). If the reflection presence / absence confirmation circuit 19B is configured to confirm the presence / absence of light reception in all the scanning regions except the monitoring region B, for example, the light beam reciprocates between the inspection reflectors m1 and m2 due to a failure or the like. Even when the received light output should be R1 = 0, it can be detected that R1 = 1 and NS = 0 can be output, and an abnormality can be detected. Further improvement Kill.
[0044]
Further, as shown by a dotted line in FIG. 7, if all the areas other than the inspection reflectors m1 to m4 in the scanning area A are included in the monitoring area B as the area B ', when there is reflected light from the area B' Since the non-existence determining means 18 side regards the reflected light from the object and the output S = 0, the angle detection circuit 19A and the reflection presence / absence confirmation circuit 19B only apply the azimuth-logical value for the existence azimuth of the inspection reflectors m1 to m4. Since the danger can be reported even in the configuration for monitoring the relationship, the reliability of the sensor can be further improved as described above.
[0045]
For example, a threshold is provided for the received light intensity of the reflected light, and when the received light intensity is equal to or greater than the threshold, it is determined that there is received light. If adjusted to a level slightly exceeding the threshold value, there are problems such as a decrease in light beam intensity due to deterioration of the light emitting element 11 and a decrease in reflected light reception intensity due to decrease in light-electric conversion efficiency due to deterioration of the light receiving element 16. There is an advantage that can be detected early. The reflectance of the inspection reflectors m1 to m4 can be adjusted by the material, color, etc. of the reflecting surface.
[0046]
In FIG. 1, the signals p1 and p2 input to the absence determination unit 18 and the normal operation confirmation unit 19 are input to one of the absence determination unit 18 and the normal operation confirmation unit 19, and the other is input to the other. A configuration may be adopted in which equivalent information signals are transmitted through means to which the signals p1 and p2 are input. For example, if the light reception output R1 is input to the absence determination means 18 and an information signal equivalent to the light reception output R1 is transmitted to the normal operation confirmation means 19 via the absence determination means 18, at least the absence determination means. 18 can confirm that the output R1 has been received, and it is also possible to confirm whether or not the processing operation of the output R1 of the absence determination means 18 is normal.
[0047]
Next, a case where the optical radar sensor has a distance measuring function will be described as a second embodiment of the present invention.
In the present embodiment, as indicated by the dotted line in FIG. 1, the signal K indicating the light emission state output from the light emitting element driving circuit 12 in synchronization with the light emission pulse is sent to the absence determination means 18 and the normal operation confirmation means 19 respectively. input. The normal operation checking means 19 includes a delay circuit 19E shown in FIG. 8 in addition to the configuration shown in FIG. 3, and the signal K is input to the delay circuit 19E. It is publicly known that the distance to the object can be calculated by the time difference between the emission of the light beam and the reception of the reflected light, the phase difference between the emission beam and the reception beam, and the details of the distance calculation method are omitted here. Since the distance from the optical radar sensor to the inspection reflectors m1 to m4 is known, each time ΔT from when the signal K is input until the reflected light from each of the inspection reflectors m1 to m4 is received is It can be calculated in advance. The ΔT varies depending on the distance from each of the inspection reflectors m1 to m4. Information on the time ΔT for each of the inspection reflectors m1 to m4 is stored in the delay circuit 19E. In the present embodiment, it is assumed that the signal Sr from the angle detection circuit 19A includes identification information of the scanning beam direction corresponding to each of the inspection reflectors m1 to m4.
[0048]
Therefore, as shown in FIG. 8, the delay circuit 19E is included in the signal Sr when the signal Sr output from the angle detection circuit 19A indicates that it is in the confirmation period of the presence or absence of light reception (when Sr = 1). Based on the azimuth information, the delay time ΔT for the corresponding inspection reflector is selected, and the signal Sr ′ = 1 is output by delaying the selection delay time ΔT from the input of the signal K.
[0049]
As a result, as shown in FIG. 9, if R1 = 1 is input when Sr ′ = 1, the reflection presence / absence confirmation circuit 19B determines that the light reception output R1 is from the reflectors m1 to m4 for inspection and sets NS = 1. continue. On the other hand, for example, as shown by a dotted line f1 in FIG. 9, if the light reception output R1 = 0 when Sr ′ = 1, NS = 0. Further, if the light reception output R1 = 0 in the scanning range of the monitoring region B in the period of Sr ′ = 0, the absence determination means 18 continuously generates the output S = 1 as no object, As indicated by the dotted line f2, when the light receiving output R1 = 1, the output of the non-existence determining means 18 is S = 0 indicating the presence of an object.
[0050]
In such a configuration, in addition to the effects similar to those of the first embodiment, when the operation delay of the light receiving element 16 or the light receiving circuit 17 increases, a time axis shift occurs between the generation timing of the signal Sr ′ and the light receiving output R1. There is an advantage that can be reported as a sensor abnormality. Further, since the monitoring area B can be set by defining the monitoring distance from the optical radar sensor, it is possible to set the desired spatial area and monitor the object.
[0051]
Next, another example of the arrangement of the inspection reflector applicable to the first and second embodiments described above will be described with reference to FIGS.
As in FIG. 1, when arranged in the vicinity of the four corners of the monitoring area B, they may be arranged as shown in FIG. 10.
Further, as shown in FIG. 11, the maximum angle θmax and the minimum angle θmin are identified for the azimuth angle θ (azimuth angle of the scanning beam) around the rotation axis 13a by the first drive circuit 14 at the outer edge of the monitoring region B. The maximum angle ψmax and the minimum angle ψmin are identified and the azimuth angles (θmax, ψmax), (θmin, ψmax), (θmax, ψmin), (θmin, Inspection reflectors m1 to m4 may be arranged in the vicinity of the (φmin) direction. This arrangement method is particularly suitable when the monitoring area B is, for example, a sphere.
[0052]
In addition, as shown in FIG. 12, some inspection reflectors m may be arranged on the floor surface. In this case, as the inspection reflector m, for example, a braille mat attached to the floor surface is conceivable. The arrangement of the inspection reflector on the floor or the like is described in detail in Japanese Patent Application Laid-Open No. 2000-162306 by the present applicant.
As in the case of the galvanometer mirror in FIG. 2, when the rotational motions of the rotational shafts 13 a and 13 b are independent, some inspection reflectors can be omitted.
[0053]
For example, as shown in FIG. 13, for the azimuth angle θ around the rotation axis 13a, the reflector m3 having the maximum angle θmax and the reflector m4 having the minimum angle θmin are selected, and the azimuth angle ψ about the rotation axis 13b is selected. A reflector m2 having a maximum angle ψmax (may be m1) and a reflector m3 having a minimum angle ψmin are selected. A reflector not selected at this time can be omitted. In FIG. 13, the inspection reflector m1 (or m2) can be omitted.
[0054]
When this arrangement method is applied, in the case of FIGS. 1 and 10, either one of the diagonal inspection reflectors, that is, the inspection reflectors m1 and m4 or m2 and m3 can be omitted.
Further, since the galvanometer mirror as shown in FIG. 2 is considered to be symmetrical in both the vertical and horizontal directions, the inspection reflector having the maximum absolute value | θ | The inspection reflector having the maximum absolute value | ψ | for the angle ± ψ can be selected, and the others can be omitted. When applied to the arrangement configuration of FIG. 1 or FIG. 10, any one of the inspection reflectors m1 to m4 may be provided.
[0055]
When a polygon mirror is used as the scanning mirror 13, the normal scanning confirmation of the light beam is replaced with the normal checking of the rotation operation, so that only one inspection reflector is required. If the scanning area A is arranged in the vicinity of the four corners, it is confirmed that the scanning area A is being scanned, so that it is possible to simultaneously confirm that the monitoring area B in the scanning area A is being scanned. Moreover, even if there are a plurality of monitoring areas B in the scanning area A, there is an advantage that it is not necessary to arrange an inspection reflector for each monitoring area B.
[0056]
Next, a case where a two-dimensional scanning optical radar sensor is mounted on a moving body will be described.
When the optical radar sensor is mounted on a moving body, it is necessary to confirm that the scanning beam is radiated to the area to be monitored, along with the normal operation of the sensor. For normal operation confirmation, if the inspection reflector for normal operation confirmation described above is fixed to the sensor, the relative position between the scanning mirror and the reflector is constant. Normal operation can be confirmed (there is no limitation due to the sensor in the travel range of the moving body). Further, when confirming that the scanning beam is radiated to the area to be monitored, an inspection reflector for confirming the radiation area is arranged in the monitoring area, and the presence or absence of reflected light from the inspection reflector is determined. Check it. In addition, it is preferable to arrange | position the test | inspection reflector for radiation | emission area | region confirmation in the vicinity of the area | region outer edge part (area | region equivalent to the monitoring area | region which a sensor should monitor) where generation | occurrence | production of a dangerous state is assumed by driving | running | working of a moving body.
[0057]
FIG. 14 shows an arrangement example of the inspection reflector when the optical radar sensor is mounted on a moving body. (A) is a top view and (B) is a side view.
In FIG. 14, a two-dimensional scanning optical radar sensor 101 attached to a moving body 100 includes an inspection reflector EaU for confirming normal operation in the same arrangement as in FIG. 1, for example, in front of a scanning mirror (not shown). EbU, EaL, and EbL are attached. The optical radar sensor 101 confirms the normal operation of the sensor 101 by the normal operation confirmation means 19 based on the reflected light of these reflectors EaU, EbU, EaL, EbL as described above.
[0058]
Further, inspection reflectors a1U to a4U, a1L to a4U, b1U to b4U for confirming the radiation area are provided at four corners in the vicinity of the outer edge of the moving space of the moving body 100 along the traveling path 102 as shown in the figure. , B1L to b4L are arranged. Each of the inspection reflectors has retroreflectivity.
The inspection reflectors a1U to a4U, a1L to a4U, b1U to b4U, b1L to b4L for confirming the radiation area are identified by the reflector position patterns and reflectors in the image obtained from the signals p1 and p2 and the received light output R1. The azimuth (and distance) information may be compared with the current position of the moving body and the predicted position pattern and expected azimuth (and distance) data of the reflector derived from the reflector position stored in advance.
[0059]
FIGS. 15A to 15C show changes in the image based on the radiation direction information of the optical radar sensor 101 and the light reception output R1 when the moving body 100 moves in the arrow direction in FIG. A region surrounded by a dotted line indicates a scanning region A of the scanning beam.
FIG. 15A shows an image at the position of FIG. 14, and inspection reflectors a2U, a2L, b2U, b2L and a3U, a3L, b3U, b3L are detected. The inspection reflectors a4U, a4L, b4U, and b4L are not detected because they are far away. As the moving body 100 moves, as shown in FIG. 15B, the inspection reflectors a2U, a2L, b2U, and b2L disappear from the image outside the scanning region, and only the inspection reflectors a3U, a3L, b3U, and b3L Will be detected. When it further moves, the inspection reflectors a4U, a4L, b4U, b4L begin to be detected as shown in FIG. As described above, when the moving body 100 moves on the traveling path 102, the inspection reflectors a1U to a4U, a1L to a4U, b1U to b4U, and b1L to b4L are detected, so that the scanning beam should be originally monitored. It can be confirmed that it is emitted to the area.
[0060]
In the configuration of FIG. 14, it is possible to omit the inspection reflectors EaU, EbU, EaL, and EbL for checking normal operation. In this case, the confirmation of the scanning beam scanning is limited to the range surrounded by the inspection reflector for confirming the radiation area detected at the outermost edge. That is, in FIGS. 15A and 15C, scanning scanning is confirmed in a range surrounded by the inspection reflectors a2U, a2L, b2U, b2L and the inspection reflectors a3U, a3L, b3U, b3L. In FIG. 15B, the measurement is performed within a range surrounded by the inspection reflectors a3U, a3L, b3U, and b3L.
[0061]
Accordingly, when the inspection reflectors EaU, EbU, EaL, and EbL for normal operation confirmation are omitted, normal operation can be confirmed in a scanning range that is substantially the same as the case of using these inspection reflectors EaU, EbU, EaL, and EbL. This is just before each of the inspection reflectors a1U to a4U, a1L to a4L, b1U to b4U, b1L to b4L for confirming the radiation area, that is, at the four corners of the image of FIG. It is the time when a4U, a1L to a4U, b1U to b4U, b1L to b4L are located, and is not continuous but becomes periodic as the moving body moves.
[0062]
The normal operation confirmation inspection reflectors EaU, EbU, EaL, and EbL are omitted, and normal operation confirmation is performed continuously in a scanning range substantially the same as that when the inspection reflectors EaU, EbU, EaL, and EbL are used. Each of the inspection reflectors a1U to a4U, a1L to a4L, b1U to b4U, and b1L to b4L for confirming the radiation region may be configured as shown in FIG.
[0063]
As shown in FIGS. 16A and 16B, the inspection reflectors aU, aL, bU, bL are continuously arranged along the traveling path 102 at the four corners in the vicinity of the outer edge of the moving space of the moving body 100.
With this configuration, as shown in FIGS. 17A to 17C, the range surrounded by the inspection reflectors aU, aL, bU, bL does not change even when the moving body 100 moves, and the inspection is not performed. Normal operation can be confirmed continuously in the same scanning range as when the reflectors EaU, EbU, EaL, and EbL are provided. H2, h3, and h4 in FIG. 17 correspond to positions h2, h3, and h4 in FIG.
[0064]
Note that the moving body on which the two-dimensional scanning optical radar sensor is mounted is not limited to the illustrated traveling vehicle but may be a robot arm or the like. In addition, when a scanning mirror such as a galvano mirror that has independent mirror rotation operations in the scanning direction is employed, a part of the inspection reflector can be omitted as described in FIG. is there.
In the case of FIGS. 14 and 16, since the radiation region confirmation inspection reflector is included in the monitoring region B, the absence determination means 18 determines the presence or absence of an object except for the light reception output R1 from the inspection reflector. It is necessary to judge. For this reason, the non-existence determination means 18 is provided with a circuit similar to the angle detection circuit 19A in the normal operation confirmation means 19 described above, and an instruction signal similar to the signal Sr is used, and when this signal Sr = 1 is input. Except for the light reception output, the presence or absence of an object is determined.
[0065]
FIGS. 18 and 19 show the difference between the case where the optical reflector sensor does not have the distance measuring function and the case where the optical reflector sensor does not have the distance measuring function when the inspection reflector existence region is excluded from the monitoring region. FIG. 18 shows a case without a distance measuring function, and FIG. 19 shows a case with a distance measuring function. In both figures, (A) is a top view and (B) is a side view. The dotted line in the figure is the scanning beam scanning area A.
[0066]
When the distance measuring function is not provided, the monitoring area B and the non-monitoring area C (area where the reflected light from the inspection reflector is received) are as illustrated, and the object 105 is the inspection reflector as illustrated. If it exists in the azimuth, there is a possibility that the reflected light of the object 105 and the reflected light of the inspection reflector cannot be discriminated. Since it is limited, it is possible to distinguish the reflected light from the object 105 and the reflected light from the inspection reflector behind the object 105. Note that it goes without saying that the above-described region segmentation method can be similarly applied to the embodiments described so far.
[0067]
Even in the case of FIG. 18, if the inspection reflector having the configuration shown in FIGS. 20 and 21 is used, the reflected light from the inspection reflector and the reflected light from the object can be distinguished.
20A and 20B are configuration examples of a movable inspection reflector configured to modulate the light intensity frequency of reflected light.
The inspection reflector 200 in FIG. 20A has a configuration in which a mirror 202 is attached to a shaft 201 that is rotated by a driving unit (not shown). If the mirror 202 has low retroreflectivity, the incident light beam is reflected in the direction corresponding to the rotation angle of the inspection reflector 200. Therefore, the reflected light from the inspection reflector 200 is modulated by the rotation frequency of the inspection reflector 200 and received by the light receiving element of the optical radar sensor. The modulation information is included in the received light output R1 and input to the reflection presence / absence confirmation circuit 19B of the normal operation confirmation means 19. When the modulated light receiving output R1 is input, the reflection presence / absence confirmation circuit 19B can be regarded as the reflected light from the inspection reflector 200 and can be distinguished from the reflected light from the object. For example, it is possible to detect that the received light signal is modulated at a specific frequency by providing a band-pass filter that passes the frequency.
[0068]
In addition, the inspection reflector 210 in FIG. 20B pivotally supports a mirror 212 so that it can swing around an axis 211, and a spring 213 is connected to the mirror 212 to supply vibration energy to the mirror 212 from the outside. And swinging. In particular, if the oscillation frequency is a resonance frequency determined by the mass of the inspection reflector 210 and the spring constant, the oscillation can be greatly oscillated. In such a configuration, for example, if the optical radar sensor is provided with sound wave generation means and vibration energy is supplied to the inspection reflector 210 by the sound wave from the sensor, the inspection reflector 210 does not need to have a drive means. There is an advantage that can be turned into a power source.
[0069]
FIG. 21 is an example of a wavelength conversion type inspection reflector configured to modulate the wavelength of reflected light.
The wavelength conversion type inspection reflector 220 in FIG. 21 has a configuration in which a wavelength conversion layer 222 is provided on the front surface of a mirror 221, and converts an incident light beam into reflected light having a different wavelength. In the present embodiment, for example, a blue incident light beam is converted into a red light beam and reflected. Such a wavelength conversion technique is disclosed in Mamiya et al .: Proceedings of the 13th Human Interface Symposium, Human Interface Subcommittee of the Society of Automatic Control, 1996, p. 493-500 and the like.
[0070]
When the wavelength conversion type inspection reflector 220 is used, for example, a light receiving element including an optical filter having a characteristic of transmitting only a red light beam and blocking a blue light beam, and a light receiving that generates a light receiving output by the output from the light receiving element. A circuit is separately provided in the optical radar sensor having the configuration shown in FIG.
As a result, the reflected light of the red light beam whose wavelength has been converted by the inspection reflector 220 is received only by the light receiving element with the optical filter, and the light reception circuit outputs the light reception output only when the reflection light of the inspection reflector 220 exists. appear. Therefore, this light reception output becomes information indicating the presence of reflected light from the inspection reflector. When this light reception output is generated, the presence / absence of the light reception output R1 is determined by the light reception presence / absence confirmation circuit 19B of the normal operation confirmation means 19. Normal operation can be confirmed.
[0071]
If the inspection reflector as shown in FIGS. 20 and 21 is used, the reflected light of the inspection reflector and the reflected light of the object can be easily distinguished, and a distance measuring function is not provided even in the state shown in FIG. Both can be identified. Further, it is possible to omit the signals p1 and p2 indicating the orientation of the inspection reflector.
It is also possible to use a radiation region checking inspection reflector as information display means. An example is shown in FIG. FIGS. 22A and 22B show an example in which travel information of the moving body 100 is displayed, for example. FIG. 22A is a top view and FIG. The same components as those in FIG. 14 are denoted by the same reference numerals.
[0072]
In FIG. 22, inspection reflectors a to c are installed on, for example, a traveling path 102 and used for information display simultaneously with the light beam radiation area confirmation of the optical radar sensor 101 mounted on the moving body 100. Information is displayed by changing a basic reflector shape (reflection characteristics), which is no information, to a predetermined shape (reflection characteristics) corresponding to the information. For example, in the present embodiment, the inspection reflector c is used as a basic shape and no information is displayed, and the basic shape is transformed into a barcode to display information. The shapes (reflection characteristics) of the inspection reflectors a to c are extracted on the basis of the signal R1, and the information is decoded from the output state of the signal R1 based on the correspondence relationship between reflectivity and information stored in advance. .
[0073]
23A to 23C show changes in the image based on the light reception output of the optical radar sensor 101 when the moving body 100 moves in the direction of the arrow in FIG.
The image (A) shows a state in which the display information of the inspection reflector a has already been decoded and executed and is approaching the inspection reflector b. In this image, the inspection reflector b is surrounded by a dotted line, and this indicates that the inspection reflector is recognized as an inspection reflector for confirming the radiation region of the light beam. It is confirmed that the beam is emitted. Assume that the inspection reflector b displays “traveling speed” information, for example, and the display information of the inspection reflector b is when the inspection reflector b overlaps the horizontal line I on the image as shown in FIG. The mobile body 100 travels based on the “traveling speed” information indicated by the inspection reflector b. In (C), the non-information inspection reflector c is confirmed, and it is confirmed only that the light beam is emitted to the monitoring area.
[0074]
With this configuration, for example, when applied to a railway vehicle, the inspection reflector can be disposed on, for example, a sleeper, and information can be provided to the vehicle by the inspection reflector. As information to be provided, for example, in addition to fixed information such as “speed limit”, “track gradient”, “distance to railroad crossing”, etc. Variable information such as “current display” and “point opening direction” can also be displayed. If stop position information is displayed, it can be used for fixed point stop control.
[0075]
The identification of the inspection reflector and the reading of the information are not limited to the method using an image as in the present embodiment, but can be performed using the direction / distance information as described above. Needless to say, the arrangement position of the inspection reflector is not limited to the traveling path. Further, information may be displayed by a combination of a plurality of inspection reflectors.
[0076]
【The invention's effect】
  Claims as described above1According to the invention, the two-dimensional scanning optical radar sensor capable of two-dimensionally scanning the scanning beam and monitoring the object in a three-dimensional space can monitor the object while confirming the normal operation. The degree of freedom of mounting the optical radar sensor on the can be increased.
[0077]
  Claim2According to the invention, in addition to the above-described effect, even when using a light beam scanning means such as a galvanometer mirror, in which scanning in each direction of the scanning beam is independently performed, confirmation of normal operation can be ensured.
  Claim3According to this invention, the reliability of the normal operation confirmation function can be improved.
  Claim4According to the invention, since the position where the inspection reflector exists is determined not only by the direction but also by the distance from the sensor, even when the inspection reflector and the object overlap each other, it is possible to identify both of them and monitor the object. Increased function reliability.
[0078]
  Claim5According to this invention, when there are a plurality of monitoring areas in the scanning area, it is not necessary to arrange an inspection reflector for each monitoring area.
  Claim7According to this invention, it is suitable even when the monitoring area is, for example, spherical.
  Claim8, 9According to the invention, the moving body can move while confirming that the scanning beam is emitted to the region to be monitored.
[0079]
  Claim10According to this invention, the reliability of the object monitoring function when the moving body is mounted can be improved.
  Claim11, 12According to this invention, since the reflected light from the inspection reflector and the reflected light from the object can be easily identified, the reliability of the normal operation confirmation function and the object monitoring function can be further enhanced.
[0080]
  Claim13According to the invention, the inspection reflector can be used not only for confirming normal operation but also for transmitting information.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a first embodiment of a two-dimensional scanning optical radar sensor according to the present invention.
FIG. 2 is a main part configuration diagram of a semiconductor galvanometer mirror applied to the embodiment.
FIG. 3 is a block diagram of normal operation confirmation means.
FIG. 4 is an explanatory diagram of a scanning beam direction.
FIG. 5 is an explanatory diagram of an arrangement principle of a reflector for inspection of a two-dimensional scanning optical radar sensor.
FIG. 6 is a time chart for explaining the operation of the normal operation confirmation unit of the first embodiment.
FIG. 7 is a diagram showing an example of setting a monitoring area
FIG. 8 is a main part configuration diagram of normal operation confirmation means of a second embodiment of the present invention having a distance measuring function;
FIG. 9 is a time chart for explaining the operation of the normal operation confirmation unit of the second embodiment.
FIG. 10 is a view showing another arrangement example of the reflector for inspection.
FIG. 11 is a diagram showing another arrangement example of the inspection reflectors;
FIG. 12 is a view showing another arrangement example of the reflector for inspection.
FIG. 13 is a view showing another arrangement example of the reflector for inspection.
FIGS. 14A and 14B show a configuration example of an inspection reflector when a moving body is mounted, where FIG. 14A is a top view and FIG. 14B is a side view;
15 is a diagram showing a change state of the moving body traveling direction screen detected by the sensor of FIG. 14;
16A and 16B show another configuration example of an inspection reflector when mounted on a moving body, where FIG. 16A is a top view and FIG. 16B is a side view.
FIG. 17 is a diagram showing a change state of the moving body traveling direction screen detected by the sensor of FIG. 16;
18A and 18B are explanatory diagrams excluding the position of the inspection reflector in the monitoring area when there is no distance measuring function, where FIG. 18A is a top view, and FIG. 18B is a side view.
FIGS. 19A and 19B are explanatory diagrams excluding the position of the inspection reflector in the monitoring area when there is a distance measuring function, where FIG. 19A is a top view and FIG. 19B is a side view;
FIG. 20 is a diagram illustrating a configuration example of an inspection reflector configured to modulate the light intensity frequency of a scanning beam;
FIG. 21 is a diagram showing a configuration example of an inspection reflector configured to modulate the wavelength of a scanning beam;
22A and 22B are diagrams showing a configuration example of an inspection reflector provided with an information display function, where FIG. 22A is a top view and FIG. 22B is a side view.
FIG. 23 is a diagram showing a change state of the moving body traveling direction screen detected by the sensor of FIG. 22;
FIG. 24 is a diagram for explaining problems when a normal operation confirmation method for a one-dimensional scanning optical radar sensor is applied to a two-dimensional scanning optical radar sensor;
[Explanation of symbols]
11 Light emitting element
12 Light emitting element drive circuit
13 Scanning mirror
14 First drive circuit
15 Second drive circuit
16 Light receiving element
17 Light receiving circuit
18 Absence determination means
19 Normal operation confirmation means
20 AND gate
m1-m4 Reflector for inspection
EaU, EbU, EaL, EbL Inspection reflector
a1U to a4U, a1L to a4U, b1U to b4U, b1L to b4L Inspection reflector
a, b, c Inspection reflector
200, 210, 220 Inspection reflector,
A Scanning area
B Monitoring area

Claims

A light beam generating means;
A light beam scanning means capable of two-dimensionally scanning a light beam from the light beam generating means including an object monitoring area;
A light receiving means for receiving reflected light from the scanning space of the scanning beam emitted from the light beam scanning means;
Non-existence determining means for determining the absence of an object in the monitoring area based on at least the output of the light receiving means;
Normal operation confirmation means for confirming at least normal operation of the light beam generating means, light beam scanning means and light receiving means;
Gate means for outputting safety information based on a logical product result of the output of the absence determination means and the output of the normal operation confirmation means ,
An angle detection circuit in which the normal operation confirmation means generates a light reception presence / absence instruction signal indicating that the scanning beam radiation direction of the light beam scanning means is an orientation in which an inspection reflector arranged in the scanning region of the scanning beam exists And a reflection presence / absence confirmation circuit that generates an output indicating that there is light reception if there is a light reception output, and a generation cycle of the light reception presence / absence indication signal. A period confirmation circuit that confirms and outputs an output indicating normal scanning speed when the generation period is a predetermined period, and an AND gate that performs an AND operation on the output of the reflection confirmation circuit and the output of the period confirmation circuit A two-dimensional scanning optical radar sensor.

The inspection reflector is disposed so that a correspondence relationship between scanning beam radiation information obtained from a sensor operation state and a light reception output result of the light receiving unit is different between an assumed abnormal operation and a normal operation. two-dimensional scanning optical radar sensor according to 1.

The angle detection circuit is a signal indicating that the scanning beam radiation azimuth of the light beam scanning means is an azimuth in which the inspection reflector exists and an azimuth in which the inspection reflector does not exist as the light reception presence / absence instruction signal. 3. The two-dimensional scanning optical radar sensor according to claim 1, wherein the reflection presence / absence confirmation circuit is configured to confirm the presence / absence of the output of the light receiving means in all directions indicated by the light reception presence / absence instruction signal. .

The two-dimensional scanning according to any one of claims 1 to 3, wherein the normal operation confirmation unit is configured to add distance information from a sensor to an inspection reflector to a light reception presence / absence instruction signal of the angle detection circuit. Type optical radar sensor.

The two-dimensional scanning optical radar sensor according to claim 1 , wherein the inspection reflector is arranged in the vicinity of a corner of the scanning region.

The two-dimensional scanning optical radar sensor according to any one of claims 1 to 4 , wherein the inspection reflector is arranged outside the monitoring area and in the vicinity of a corner of the monitoring area.

The two-dimensional scanning type according to any one of claims 1 to 4 , wherein the inspection reflector is arranged in the vicinity of an azimuth indicated by a maximum vertical angle and a horizontal maximum angle of a scanning beam with respect to an outer edge of the monitoring region. Optical radar sensor.

When a two-dimensional scanning optical radar sensor is mounted on a moving body, when the moving body moves within a predetermined range, at least one inspection reflector is present in the monitoring area. The two-dimensional scanning optical radar sensor according to any one of claims 1 to 4 , which is arranged.

The two-dimensional scanning optical radar sensor according to claim 8 , wherein the inspection reflector is arranged so as to continuously exist along a moving direction of the moving body.

10. The configuration according to claim 8 , wherein the absence determination unit is configured to determine the presence / absence of an object by excluding a light reception output by reflected light from the inspection reflector in the monitoring region from a light reception output of the light reception unit. The two-dimensional scanning optical radar sensor described.

The two-dimensional scanning optical radar sensor according to any one of claims 1 to 10 , wherein the inspection reflector is configured to modulate a light intensity frequency of an incident scanning beam.

The two-dimensional scanning optical radar sensor according to any one of claims 1 to 10 , wherein the inspection reflector is configured to modulate a wavelength of an incident scanning beam.

The two-dimensional scanning optical radar sensor according to claim 1 , wherein the inspection reflector is used as an information display unit.