JP3876097B2

JP3876097B2 - 3D position and orientation detection sensor

Info

Publication number: JP3876097B2
Application number: JP20443799A
Authority: JP
Inventors: 正良加藤
Original assignee: Ricoh Co Ltd
Current assignee: Ricoh Co Ltd
Priority date: 1999-07-19
Filing date: 1999-07-19
Publication date: 2007-01-31
Anticipated expiration: 2019-07-19
Also published as: JP2001033208A

Description

【０００１】
【発明の属する技術分野】
本発明は、三次元位置及び姿勢検出センサすなわち、物体の変位および傾斜を同時に計測する光センサに関する。
【０００２】
【従来の技術】
変位センサに傾き測定用光学系を付加し、変位と同時に傾きを測定できるようにした、物体の変位・傾き検出用の光センサとして、特開平８−２４０４０８号公報に開示されたものがある。この光センサは、図９に示すように変位測定用光学系と、傾き測定用光学系とを備えており、上記変位測定用光学系は検出領域に向けて変位測定用光を出射する変位測定用光源部と、検出領域で反射された変位測定用光を受光する変位測定用受光部とからなり、上記傾き測定用光学系は検出領域にある物体の傾きを検出できるように構成されている。
【０００３】
すなわち図９において、変位測定用投光素子５８からの変位測定用光５５をダイクロイックミラー５７に透過させた後、投光レンズ６０で集光させて検出物体７１の表面に照射する。検出物体７１で反射した変位測定用光５５を受光レンズ６３で集光し、ダイクロイックミラー６４に選択的に通過させて変位測定用受光素子６１に結像させる。傾き測定用投光素子５９からの傾き測定用光５６をダイクロイックミラー５７で反射させた後、投光レンズ６０でコリメートして検出物体７１の表面に照射する。検出物体７１で反射した傾き測定用光５６を受光レンズ６３で集光し、ダイクロイックミラー６４で選択的に反射させて傾き測定用受光素子６２に集光させる。
【０００４】
図９の光センサでは、変位測定用投光素子５８、投光レンズ６０、受光レンズ６３および変位測定用受光素子６１によって変位測定用光学系が構成されている。また、傾き測定用投光素子５９、投光レンズ６０、受光レンズ６３および傾き測定用受光素子６２によって傾き測定用光学系が構成されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、上記光センサでは変位方向が一方向のみの場合について検出することはできるものの、三次元での計測を行うことはできない。このため、三次元計測を可能とするには、これらの光センサを互いに直交する３軸上に設置する必要があり、装置が大型化してしまう問題があった。また、測定対象物の設置には空間的な制約が加わってしまう。さらに、測定対象部分は原理的に照射ビームスポットが基準になるため、並進運動により対象点が変化してしまい、対象とする計測物の三次元的な動きを正確に計測することは困難であった。
【０００６】
本発明は、上記問題点に鑑みなされたもので、その目的は、三次元の位置情報を精度良く得ることができ、しかも小型化が可能な光計測装置を安価に提供することにある。
【０００７】
【課題を解決するための手段】
請求項１に係る三次元位置及び姿勢検出センサは、光ビームを所定の測定領域に投光して、その反射および散乱光を位置検出素子上に集光または結像して光スポットを形成し、その位置情報から三角測量方式により前記測定領域の変位を計測する光計測装置において、測定領域に所定の中心部が拡散面形状を有し、前記中心部以外の周辺部が反射面形状を有するマーカを少なくとも一つ設置し、少なくとも一つの概略平行な前記投光用光ビームを前記マーカ中心部が前記光ビーム内に包含されるように既知の角度から照射し、前記マーカ中心部からの散乱光と周辺部からの反射光をそれぞれ角度検出用光学系を有する傾き検出部により受光して、それら集光スポットの位置情報を基に前記マーカの位置および傾き情報を検出することを特徴とする。
【０００８】
また、請求項２に係る三次元位置及び姿勢検出センサは、請求項１のセンサにおいて、既知の角度を有する方向から概略平行な光ビームを前記マーカに照射し、所定の既知の２つの異なる場所に、前記マーカ中心部からの拡散光を角度検出用光学系により集光してその光スポット位置を検出する位置検出素子を設置してマーカ中心部の位置情報を検出するとともに、前記マーカ周辺部からの反射戻り光をもとに前記角度検出用光学系を有する傾き検出部によりマーカの傾き角情報を検出し、三次元位置および姿勢を算出することを特徴とする。
【０００９】
さらに、請求項３に係る三次元位置及び姿勢検出センサは、請求項２のセンサにおいて、前記マーカの設置してある平面との角度関係が既知の鏡面状の表面を有する平面に概略平行な光ビームを照射し、反射戻り光を前記角度検出用光学系を有する傾き検出部により前記マーカの垂直方向回りの傾きを計測して計測対象物の３軸６自由度の三次元位置および姿勢を算出することを特徴とする。
【００１０】
さらに、請求項４に係る三次元位置及び姿勢検出センサは、請求項１，２または３のセンサにおいて、前記角度検出用光学系が低収差レンズからなり、該レンズの光軸に位置検出素子の受光面が垂直で、かつその中心が前記レンズの焦点位置にあるように設置してなる角度検出部であることを特徴とする。
【００１１】
さらに、請求項５に係る三次元位置及び姿勢検出センサは、請求項１のセンサにおいて、前記位置検出素子として、入射スポット光により発生するキャリアが空間的に分離されて検出される受光素子を用い、受光された光スポット位置の重心を検出する際に、所定の受光光量レベル以上のスポット像を検出し、その強度情報および幾何学形状から得られる重心位置を前記光スポット位置情報として測定領域の位置情報を検出することを特徴とする。
【００１２】
さらに、請求項６に係る三次元位置及び姿勢検出センサは、請求項１のセンサにおいて、姿勢角度検出用照明光ビームと位置検出用照射光ビームに所定の異なる波長の光源を用い、合波およびコリメートして前記マーカ部に照射し、少なくとも一方の波長を透過させる光学フィルタを少なくとも一つの傾き検出部に挿入するとともに、前記波長の光出力をもう一方の光出力に対して小さくしたことを特徴とする。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態を、図面を参照しながら説明する。
第１の実施の形態
図１は三次元位置及び姿勢検出センサの構成を示す概略斜視図である。図２はこのセンサに配備されたマーカを示すもので、（ａ）は斜視図、（ｂ）は側面図である。図３はこのセンサにより測定対象物の空間位置および角度の情報を得るシステムの構成説明図である。図４はこのセンサによる三次元位置および姿勢検出の原理説明図、図５はこのセンサによる角度検出の原理説明図である。
【００１４】
上記センサでは、図１に示すような光源（レーザダイオード、発光ダイオードなど）７と、その出射光をコリメートするレンズ６からなる光源部を有し、所定のビーム径（これは測定対象物の測定範囲に関係して決められる）の平行光を既知の角度（本実施の形態では鉛直方向上向き）で、測定対象物２の所定部位１に照射する。この測定部位１には、図２に示すようなマーカ１０を設置する。このマーカ１０では、光源光が入射する側の表面中心部に拡散反射部（マーカ中心部）１０ａが形成され、前記中心部の周りの周辺部表面１０ｂは、光源光に対し正反射面となるように表面加工が施されている。
【００１５】
また、図１に示すように上記光源部（６，７）からの照射光ビームＬａ内にマーカ１０が存在するときのマーカ１０の中心部１０ａからの拡散光１０Ａに対し、図５に示すように低収差なレンズ３ａ（４ａ）と、位置検出素子３ｂ（４ｂ）とを既知の位置に設置することにより角度検出部３（４）を構成する。この場合、低収差レンズ３ａ（４ａ）は、位置検出素子３ｂ（４ｂ）の受光面から前記レンズの焦点距離分だけ離れた光軸上に設置する。図１において８，９はハーフプリズムであり、Ｘ，Ｙ，Ｚは三次元の直交座標軸を示している。
【００１６】
いま、角度検出部３（角度検出部４の場合についても同様である）と拡散反射部１０ａとの距離が、この拡散反射部１０ａの直径に比べて十分に大きい場合、拡散反射部１０ａからの拡散光１０Ａは、低収差レンズ３ａに対し、マーカ中心部１０ａからの平行光とほぼ等価となり、位置検出素子３ｂ上の、レンズ焦点距離と入射角にのみ依存する位置にスポット像を結像することになる。
【００１７】
本実施の形態では直交する上記二つのスポット位置情報と、上記角度検出部の配置位置情報とからマーカ中心部１０ａの三次元位置情報を算出する。また、マーカ周辺部１０ｂからの反射戻り光をハーフプリズム９を介して、図５に示した角度検出部（傾き検出部）３，４と構成が同じである姿勢角度検出用の傾き検出部５（５ａは低収差レンズ、５ｂは位置検出素子）を用いてマーカ１０部分の傾き（姿勢）を前記原理で検出することにより、マーカ部つまり測定対象物２の姿勢角状態を、位置と同時に検出する。すなわち、図３に示すように位置検出素子３ｂ，４ｂからのスポット位置情報１１，１２をもとに、マーカ中心部の方向ベクトルを算出し、これと傾き検出部３，４の配置位置情報とから三次元位置を算出すると同時に、上記位置検出素子５ｂからのスポット位置情報１３に基づいて姿勢角を算出する（図３の符号１４〜１６）ことにより、マーカの三次元位置および姿勢を検出する（符号１７）。
【００１８】
つぎに、三次元位置（空間位置）および姿勢（角度）の算出原理を、図４を参照して説明する。なお説明を簡単にするため、ここでは（１）レンズ３ａ，４ａの中心部Ｌ１，Ｌ２はＸＹ平面上に存在し、（２）傾き検出部５を構成するレンズ５ａの光軸はＺ軸と一致し、（３）傾き検出部５の位置検出素子５ｂの中心は原点Ｏと一致し、（４）照射ビームの光軸はＺ軸と一致しているものとする。
【００１９】
いま、受光素子５ｂ上の反射光のスポット位置をＤ（Ｘａ，Ｙａ）とすると、レンズの焦点距離ｆにより、マーカ１０の中心における法線ベクトルｎは、マーカ中心部１０ａから傾き検出部の光学中心への方向ベクトルＲ（図略）と、照射ビームの方向ベクトルＢ（図略）とにより、光の反射の法則などの関係から下記［数１］以下の数式より求めることができる。ただし、上記方向ベクトルＲとＺ軸とのなす角をθとし、この方向ベクトルＲのＸＹ平面への正射影像とＸ軸とのなす角をφとする。
【００２０】
【数１】

【００２１】
また、レンズが理想的なものであるとすると、フーリエ変換光学系においてθおよびφは、次の［数２］により求まる。これによって、マーカ部の傾き（姿勢）を算出する。
【００２２】
【数２】

【００２３】
さらに、上記法線ベクトルｎを単位ベクトルとすると、
【００２４】
【数３】

【００２５】
また、上記フーリエ変換光学系の性質から、傾き検出部３，４で検出および算出されるマーカ中心部への方向ベクトルａ_i（ｉ＝１，２）により、それぞれのレンズ中心位置Ｌ_i（ｉ＝１，２）と、マーカ中心部とを通る直線の式は次の［数４］のように表される。
【００２６】
【数４】

【００２７】
よって、ｉ＝１の直線とｉ＝２の直線との交点が、測定するべきマーカ１０の三次元位置となる。実際にはＰＳＤなどの位置検出素子によりスポットの光量分布の重心位置を検出して方向ベクトルとするため、完全に一点で交わるとは限らないが、その際は二つの直線が最も接近する各直線上の２点の一方を測定点とするか、またはその二点間の中点を観測点としても大きな誤差は生じない。
【００２８】
第２の実施の形態
図６は、三次元位置及び姿勢検出センサの構成を示す概略斜視図である。この図において、マーカ１０が設置されている平面との角度関係が既知の測定対象物の鏡面状平面３０を有する概略平面となる部位、または上記既知の部位に平面反射鏡３１を設置して、これに平行光ビームＬｂを照射し、その反射戻り光を上記角度検出用光学系を有する同様の傾き検出部（レンズ２８と位置検出素子２９）により角度変化を上記原理で検出し、その計測面とマーカ１０との幾何学的関係から、マーカ１０の法線方向回りの傾き角を検出することにより、マーカ部の３軸６自由度の変化を検出することが可能となる。なお、図６において２５は光源、２６はレンズ、２７はハーフプリズムである。
【００２９】
第３の実施の形態
図７は、三次元位置及び姿勢検出センサの要部構成説明図であって、このセンサは検出位置精度を向上させることができる受光素子を配備したものである。図７において、位置検出素子としてＣＣＤのような、入射スポットにより発生するキャリアが空間的に分離されて検出される受光素子３４を用い、受光された光スポット３３の重心位置を検出するときに、所定の受光光量レベル以上のスポット像３５を計算し、このスポット像３５の光量分布およびその幾何学形状から算出される重心位置を、上記光スポット３３の受光面上の位置情報とする。これにより、斜め入射時のレンズ収差などによる重心位置の検出誤差に起因する検出位置精度の劣化を低減することが可能となる。
【００３０】
第４の実施の形態
図８は三次元位置及び姿勢検出センサの構成を示す概略斜視図であり、本実施の形態は、姿勢角検出部では比較的広範囲の光ビームを集光することから、マーカ中心部からの拡散光に比べ受光光量で有利であることを利用したものである。すなわち、光源４１による姿勢角度検出用光ビームと、光源４２による、波長が上記姿勢角度検出用光ビームと異なる位置検出用光ビームとを得るとともに、これらの光ビームを合波して、測定対象物２の所定部位１に照射し、それぞれの位置検出素子上、たとえば本実施の形態では姿勢角度検出用光学系に一方の波長光のみを透過させる光学フィルタ４５を挿入し、対応する波長の照射光ビーム４１の光出力を抑え、他方の照射光ビームの光出力を増大させることにより、姿勢角検出部５での受光量を確保しつつ、位置検出用傾き角検出部３，４の受光光量を増加させ、Ｓ／Ｎ比を向上させることが可能である。図８において４０はレンズ、４３および４４はハーフプリズムである。
【００３１】
なお、本発明は上記実施の形態に限定されるものではなく、特許請求の範囲に記載された事項の範囲内で種々の変形が可能である。例えば、上記した計測用の光ビームおよび検出部の配置は、それらの空間的関係が既知であれば種々の配置が可能である。
【００３２】
【発明の効果】
以上の説明で明らかなように、本発明によれば以下の効果が得られる。
（１）請求項１，２，３に係る発明の効果
三次元位置情報を高精度に検出することが可能な計測装置（センサ）を提供することができる。また、本発明の計測装置は小型化が容易であるうえ、安価に製作することができる。
（２）請求項４に係る発明の効果
高精度な角度検出部を、簡単な構成で提供することができる。
（３）請求項５に係る発明の効果
斜め入射やレンズ収差による光スポット像の光量分布変化に起因する位置検出精度の劣化が低減でき、安価で高精度の計測装置を提供することができる。
（４）請求項６に係る発明の効果
姿勢角検出部での受光量を確保しつつ、位置検出部のＳ／Ｎ比を向上させることができ、高精度な計測装置を提供することが可能である。
【図面の簡単な説明】
【図１】第１の実施の形態に係る三次元位置及び姿勢検出センサの構成を示す概略斜視図である。
【図２】図１のセンサに配備されたマーカを示すもので、（ａ）は斜視図、（ｂ）は側面図である。
【図３】図１のセンサにより測定対象物の空間位置および角度の情報を得るシステムの構成説明図である。
【図４】図１のセンサによる三次元位置および姿勢検出の原理説明図である。
【図５】図１のセンサによる角度検出の原理説明図である。
【図６】第２の実施の形態に係る三次元位置及び姿勢検出センサの構成を示す概略斜視図である。
【図７】第３の実施の形態に係る三次元位置及び姿勢検出センサの要部構成説明図である。
【図８】第４の実施の形態に係る三次元位置及び姿勢検出センサの構成を示す概略斜視図である。
【図９】物体の変位・傾き検出用光センサの従来例を示す説明図である。
【符号の説明】
１所定部位
２測定対象物
３，４角度検出部（傾き検出部）
３ａ，４ａ低収差レンズ
３ｂ，４ｂ位置検出素子
５傾き検出部（姿勢角検出部）
５ａ低収差レンズ
５ｂ位置検出素子（受光素子）
６レンズ
７光源
８，９ハーフプリズム
１０マーカ
１０Ａ拡散光
１０ａ拡散反射部
（マーカ中心部）
１０ｂ周辺部表面
１１，１２スポット位置情報
１３スポット位置情報
２５光源
２６レンズ
２７ハーフプリズム
２８レンズ
２９位置検出素子
３０鏡面状平面
３１平面反射鏡
３３光スポット
３４受光素子
３５スポット像
４０レンズ
４１，４２光源
４３，４４ハーフプリズム
４５光学フィルタ
５５変位測定用光
５６傾き測定用光
５７ダイクロイックミラー
５８変位測定用投光素
５９傾き測定用投光素子
６０投光レンズ
６１変位測定用受光素子
６２傾き測定用受光素子
６３受光レンズ
６４ダイクロイックミラー
７１検出物体
Ｌ１レンズ３ａの中心部
Ｌ２レンズ４ａの中心部
Ｌａ照射光ビーム
Ｌｂ平行光ビーム[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional position and orientation detection sensor, that is, an optical sensor that simultaneously measures displacement and inclination of an object.
[0002]
[Prior art]
An optical sensor for detecting displacement / inclination of an object in which an inclination measuring optical system is added to the displacement sensor so that the inclination can be measured simultaneously with the displacement is disclosed in Japanese Patent Laid-Open No. 8-240408. As shown in FIG. 9, the optical sensor includes a displacement measurement optical system and an inclination measurement optical system, and the displacement measurement optical system emits displacement measurement light toward a detection region. A light source unit for displacement and a light receiving unit for displacement measurement that receives the light for displacement measurement reflected by the detection region, and the tilt measurement optical system is configured to detect the tilt of the object in the detection region. .
[0003]
That is, in FIG. 9, the displacement measurement light 55 from the displacement measurement light projecting element 58 is transmitted through the dichroic mirror 57, then condensed by the light projection lens 60 and irradiated onto the surface of the detection object 71. The displacement measuring light 55 reflected by the detection object 71 is collected by the light receiving lens 63 and selectively passed through the dichroic mirror 64 to form an image on the displacement measuring light receiving element 61. After the tilt measurement light 56 from the tilt measurement light projecting element 59 is reflected by the dichroic mirror 57, it is collimated by the light projection lens 60 and irradiated onto the surface of the detection object 71. The tilt measurement light 56 reflected by the detection object 71 is collected by the light receiving lens 63, selectively reflected by the dichroic mirror 64, and collected on the tilt measurement light receiving element 62.
[0004]
In the optical sensor of FIG. 9, a displacement measuring optical system is configured by the displacement measuring light projecting element 58, the light projecting lens 60, the light receiving lens 63, and the displacement measuring light receiving element 61. The tilt measuring optical system is constituted by the tilt measuring light projecting element 59, the light projecting lens 60, the light receiving lens 63 and the tilt measuring light receiving element 62.
[0005]
[Problems to be solved by the invention]
However, although the above optical sensor can detect the case where the displacement direction is only one direction, it cannot measure in three dimensions. For this reason, in order to enable three-dimensional measurement, it is necessary to install these optical sensors on three axes orthogonal to each other, and there is a problem that the apparatus becomes large. In addition, a spatial restriction is added to the installation of the measurement object. Furthermore, because the measurement target part is based on the irradiation beam spot in principle, the target point changes due to translational movement, and it is difficult to accurately measure the three-dimensional movement of the target measurement object. It was.
[0006]
The present invention has been made in view of the above problems, and an object of the present invention is to provide an inexpensive optical measurement apparatus that can obtain three-dimensional position information with high accuracy and can be miniaturized.
[0007]
[Means for Solving the Problems]
The three-dimensional position and orientation detection sensor according to claim 1 projects a light beam onto a predetermined measurement region and collects or forms an image of the reflected and scattered light on the position detection element to form a light spot. In the optical measurement device that measures the displacement of the measurement region from the position information by the triangulation method, the measurement region has a predetermined central portion having a diffusing surface shape, and a peripheral portion other than the central portion has a reflecting surface shape. At least one marker is placed, and at least one substantially parallel light beam for projection is irradiated from a known angle so that the marker central portion is included in the light beam, and scattered from the marker central portion. The light and the reflected light from the peripheral part are received by an inclination detection unit having an angle detection optical system, respectively, and the position and inclination information of the marker is detected based on the position information of the condensed spots. That.
[0008]
A three-dimensional position and orientation detection sensor according to claim 2 is the sensor according to claim 1, wherein the marker is irradiated with a substantially parallel light beam from a direction having a known angle, and two predetermined known different locations. In addition, a position detection element for condensing the diffused light from the marker center by an angle detection optical system and detecting the light spot position is installed to detect the position information of the marker center, and the marker periphery The tilt angle information of the marker is detected by the tilt detector having the angle detection optical system based on the reflected return light from the beam, and the three-dimensional position and orientation are calculated.
[0009]
Furthermore, the three-dimensional position and orientation detection sensor according to claim 3 is a light substantially parallel to a plane having a mirror-like surface whose angular relationship with the plane on which the marker is installed is known. A beam is irradiated, and the reflected return light is measured by the inclination detector having the angle detection optical system to measure the inclination of the marker around the vertical direction, and the three-dimensional position and orientation of the measurement object in three axes and six degrees of freedom are calculated. It is characterized by doing.
[0010]
Furthermore, the three-dimensional position and orientation detection sensor according to claim 4 is the sensor according to

claim

1, 2 or 3, wherein the angle detection optical system is a low aberration lens, and the position detection element is arranged on the optical axis of the lens. The angle detection unit is installed such that the light receiving surface is vertical and the center thereof is at the focal position of the lens.
[0011]
Furthermore, the three-dimensional position and orientation detection sensor according to claim 5 uses, in the sensor according to claim 1, a light receiving element that detects a carrier generated by incident spot light as being spatially separated as the position detection element. When detecting the center of gravity of the received light spot position, a spot image having a predetermined received light amount level or more is detected, and the center of gravity position obtained from the intensity information and the geometric shape is used as the light spot position information in the measurement region. It is characterized by detecting position information.
[0012]
Furthermore, the three-dimensional position and orientation detection sensor according to claim 6 is the sensor according to claim 1, wherein light sources having predetermined different wavelengths are used for the orientation angle detection illumination light beam and the position detection illumination light beam, An optical filter that collimates and irradiates the marker unit and transmits at least one wavelength is inserted into at least one tilt detection unit, and the optical output of the wavelength is made smaller than the other optical output. And
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First Embodiment FIG. 1 is a schematic perspective view showing the configuration of a three-dimensional position and orientation detection sensor. 2A and 2B show a marker provided on the sensor. FIG. 2A is a perspective view and FIG. 2B is a side view. FIG. 3 is a diagram illustrating the configuration of a system that obtains information on the spatial position and angle of the measurement object using this sensor. FIG. 4 is a diagram for explaining the principle of three-dimensional position and orientation detection by this sensor, and FIG. 5 is a diagram for explaining the principle of angle detection by this sensor.
[0014]
The above sensor has a light source portion including a light source (laser diode, light emitting diode, etc.) 7 as shown in FIG. 1 and a lens 6 for collimating the emitted light, and has a predetermined beam diameter (this is the measurement of the measurement object). The predetermined portion 1 of the measurement object 2 is irradiated with parallel light (determined in relation to the range) at a known angle (vertically upward in the present embodiment). A marker 10 as shown in FIG. In this marker 10, a diffuse reflection part (marker center part) 10a is formed at the center of the surface on the side where the light source light is incident, and the peripheral surface 10b around the center part is a regular reflection surface for the light source light. Surface treatment is applied.
[0015]
Further, as shown in FIG. 5, the diffused light 10A from the central portion 10a of the marker 10 when the marker 10 is present in the irradiation light beam La from the light source portion (6, 7) as shown in FIG. In addition, the angle detector 3 (4) is configured by installing the lens 3a (4a) having a low aberration and the position detecting element 3b (4b) at a known position. In this case, the low aberration lens 3a (4a) is installed on the optical axis that is separated from the light receiving surface of the position detection element 3b (4b) by the focal length of the lens. In FIG. 1, 8 and 9 are half prisms, and X, Y, and Z indicate three-dimensional orthogonal coordinate axes.
[0016]
If the distance between the angle detector 3 (the same applies to the angle detector 4) and the diffuse reflector 10a is sufficiently larger than the diameter of the diffuse reflector 10a, the distance from the diffuse reflector 10a is as follows. The diffused light 10A is substantially equivalent to the parallel light from the marker central portion 10a with respect to the low aberration lens 3a, and forms a spot image at a position on the position detection element 3b that depends only on the lens focal length and the incident angle. It will be.
[0017]
In the present embodiment, the three-dimensional position information of the marker center portion 10a is calculated from the two spot position information orthogonal to each other and the arrangement position information of the angle detection unit. Further, the reflected angle of the reflected return light from the marker peripheral portion 10b via the half prism 9 is the same as the angle detectors (tilt detectors) 3 and 4 shown in FIG. (5a is a low aberration lens, 5b is a position detection element) By detecting the inclination (posture) of the marker 10 portion based on the above principle, the posture angle state of the marker portion, that is, the measurement object 2 is detected simultaneously with the position. To do. That is, as shown in FIG. 3, based on the

spot position information

11 and 12 from the

position detection elements

3b and 4b, the direction vector of the marker center portion is calculated, and the arrangement position information of the

inclination detection units

3 and 4 and At the same time as calculating the three-dimensional position from the above, the posture angle is calculated based on the spot position information 13 from the position detecting element 5b (reference numerals 14 to 16 in FIG. 3), thereby detecting the three-dimensional position and posture of the marker. (Reference numeral 17).
[0018]
Next, the calculation principle of the three-dimensional position (spatial position) and posture (angle) will be described with reference to FIG. In order to simplify the description, here, (1) the center portions L1 and L2 of the

lenses

3a and 4a are present on the XY plane, and (2) the optical axis of the lens 5a constituting the tilt detection unit 5 is the Z axis. (3) It is assumed that the center of the position detection element 5b of the tilt detection unit 5 is coincident with the origin O, and (4) the optical axis of the irradiation beam is coincident with the Z axis.
[0019]
Now, assuming that the spot position of the reflected light on the light receiving element 5b is D (Xa, Ya), the normal vector n at the center of the marker 10 is changed from the marker central part 10a to the optical of the inclination detecting part by the focal length f of the lens. From the relation of the light reflection law and the like, the following equation (1) can be obtained from the direction vector R (not shown) to the center and the direction vector B (not shown) of the irradiation beam. However, the angle between the direction vector R and the Z axis is θ, and the angle between the orthogonal projection image of the direction vector R on the XY plane and the X axis is φ.
[0020]
[Expression 1]

[0021]
Further, assuming that the lens is ideal, θ and φ in the Fourier transform optical system can be obtained by the following [Equation 2]. Thereby, the inclination (posture) of the marker portion is calculated.
[0022]
[Expression 2]

[0023]
Furthermore, when the normal vector n is a unit vector,
[0024]
[Equation 3]

[0025]
Further, due to the nature of the Fourier transform optical system, each lens center position L _i (i) is determined by the direction vector a _i (i = 1, 2) to the marker center detected and calculated by the

inclination detectors

3 and 4. = 1, 2) and a straight line that passes through the center of the marker is expressed by the following [Equation 4].
[0026]
[Expression 4]

[0027]
Therefore, the intersection of the straight line with i = 1 and the straight line with i = 2 is the three-dimensional position of the marker 10 to be measured. Actually, since the center of gravity of the spot light quantity distribution is detected by a position detection element such as PSD and used as a direction vector, it does not always completely intersect at one point. Even if one of the above two points is used as a measurement point, or a midpoint between the two points is used as an observation point, a large error does not occur.
[0028]
Second Embodiment FIG. 6 is a schematic perspective view showing the configuration of a three-dimensional position and orientation detection sensor. In this figure, a plane reflecting mirror 31 is installed at a site that is a schematic plane having a mirror-like plane 30 of a measurement object having a known angular relationship with the plane on which the marker 10 is installed, or the known site, This is irradiated with a parallel light beam Lb, and the reflected return light is detected by the same inclination detection unit (lens 28 and position detection element 29) having the angle detection optical system in accordance with the principle described above, and its measurement surface By detecting the inclination angle around the normal direction of the marker 10 from the geometric relationship between the marker 10 and the marker 10, it is possible to detect a change in the three-axis six-degree-of-freedom of the marker portion. In FIG. 6, 25 is a light source, 26 is a lens, and 27 is a half prism.
[0029]
Third Embodiment FIG. 7 is an explanatory diagram of the main part configuration of a three-dimensional position and orientation detection sensor. This sensor is provided with a light receiving element capable of improving detection position accuracy. In FIG. 7, when detecting the center of gravity of the received light spot 33 using a light receiving element 34 such as a CCD that detects carriers generated by incident spots spatially separated as a position detecting element, A spot image 35 having a level equal to or greater than a predetermined received light amount is calculated, and the position of the center of gravity calculated from the light amount distribution and the geometric shape of the spot image 35 is used as position information on the light receiving surface of the light spot 33. As a result, it is possible to reduce the deterioration of the detection position accuracy caused by the detection error of the center of gravity position due to the lens aberration at the time of oblique incidence.
[0030]
Fourth Embodiment FIG. 8 is a schematic perspective view showing the configuration of the three-dimensional position and orientation detection sensor. In this embodiment, the posture angle detector collects a relatively wide range of light beams. The advantage is that the amount of received light is more advantageous than the diffused light from the center of the marker. That is, a posture angle detection light beam by the light source 41 and a position detection light beam having a wavelength different from the posture angle detection light beam by the light source 42 are obtained, and these light beams are combined to be measured. Irradiate a predetermined part 1 of the object 2, insert an optical filter 45 that transmits only one wavelength light into each position detection element, for example, an attitude angle detection optical system in this embodiment, and irradiate the corresponding wavelength. By suppressing the light output of the light beam 41 and increasing the light output of the other irradiation light beam, the amount of light received by the position detection tilt

angle detection units

3 and 4 is ensured while ensuring the amount of light received by the posture angle detection unit 5. And the S / N ratio can be improved. In FIG. 8, 40 is a lens, and 43 and 44 are half prisms.
[0031]
In addition, this invention is not limited to the said embodiment, A various deformation | transformation is possible within the range of the matter described in the claim. For example, the arrangement of the measurement light beam and the detection unit described above can be variously arranged if their spatial relationship is known.
[0032]
【The invention's effect】
As is apparent from the above description, the present invention provides the following effects.
(1) Effects of the Inventions According to

Claims

1, 2, and 3 A measuring device (sensor) capable of detecting three-dimensional position information with high accuracy can be provided. Further, the measuring device of the present invention can be easily downsized and can be manufactured at low cost.
(2) Advantageous Effects of Invention According to Claim 4 A highly accurate angle detector can be provided with a simple configuration.
(3) The effect of the invention according to claim 5 It is possible to reduce the deterioration of the position detection accuracy due to the change in the light amount distribution of the light spot image due to the oblique incidence or lens aberration, and it is possible to provide an inexpensive and highly accurate measuring device.
(4) According to the sixth aspect of the invention, the S / N ratio of the position detector can be improved while ensuring the amount of light received by the posture angle detector, and a highly accurate measuring device can be provided. It is.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing a configuration of a three-dimensional position and orientation detection sensor according to a first embodiment.
2A and 2B show a marker provided on the sensor of FIG. 1, in which FIG. 2A is a perspective view and FIG. 2B is a side view.
FIG. 3 is a configuration explanatory diagram of a system that obtains information on a spatial position and an angle of a measurement object using the sensor of FIG. 1;
4 is a diagram for explaining the principle of three-dimensional position and orientation detection by the sensor of FIG. 1; FIG.
FIG. 5 is an explanatory diagram of the principle of angle detection by the sensor of FIG. 1;
FIG. 6 is a schematic perspective view illustrating a configuration of a three-dimensional position and orientation detection sensor according to a second embodiment.
FIG. 7 is an explanatory diagram of a main part configuration of a three-dimensional position and orientation detection sensor according to a third embodiment.
FIG. 8 is a schematic perspective view illustrating a configuration of a three-dimensional position and orientation detection sensor according to a fourth embodiment.
FIG. 9 is an explanatory diagram showing a conventional example of an optical sensor for detecting displacement / tilt of an object.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Predetermined part 2

Measurement object

3, 4 Angle detection part (inclination detection part)
3a, 4a

Low aberration lenses

3b, 4b Position detection element 5 Inclination detector (attitude angle detector)
5a Low aberration lens 5b Position detecting element (light receiving element)
6 Lens 7 Light source 8, 9 Half prism 10 Marker 10A Diffuse light 10a Diffuse reflection part (marker center part)
10b

Peripheral surface

11, 12 Spot position information 13 Spot position information 25 Light source 26 Lens 27 Half prism 28 Lens 29 Position detecting element 30 Specular plane 31 Planar reflecting mirror 33 Light spot 34 Light receiving element 35 Spot image 40

Lens

41, 42

Light source

43, 44 Half prism 45 Optical filter 55 Displacement measuring light 56 Tilt measuring light 57 Dichroic mirror 58 Displacement measuring light projecting element 59 Tilt measuring light projecting element 60 Projecting lens 61 Displacement measuring light receiving element 62 Tilt measuring light receiving Element 63 Light receiving lens 64 Dichroic mirror 71 Detection object L1 Center part L2 of lens 3a Center part La of lens 4a Irradiation light beam Lb Parallel light beam

Claims

A light beam is projected onto a predetermined measurement area, and the reflected and scattered light is condensed or imaged on a position detection element to form a light spot, and the displacement of the measurement area is determined by triangulation from the position information. In the optical measuring device to measure, at least one marker having a diffusing surface shape at a predetermined central portion in the measurement region and having a reflecting surface shape at a peripheral portion other than the central portion is provided. The projection light beam is irradiated from a known angle so that the marker center portion is included in the light beam, and the angle detection optical system respectively reflects the scattered light from the marker center portion and the reflected light from the peripheral portion. A three-dimensional position and orientation detection sensor that receives light by an inclination detection unit having a position and detects the marker position and inclination information based on the position information of the focused spots.

The marker is irradiated with a substantially parallel light beam from a direction having a known angle, and diffused light from the center of the marker is condensed at two predetermined known locations by an angle detection optical system. A position detection element for detecting the spot position is installed to detect the position information of the center of the marker, and the inclination detection unit having the angle detection optical system based on the reflected return light from the periphery of the marker is used to detect the marker. The three-dimensional position and orientation detection sensor according to claim 1, wherein inclination angle information is detected and a three-dimensional position and orientation are calculated.

A plane having a mirror-like surface with a known angular relationship with the plane on which the marker is installed is irradiated with a light beam substantially parallel, and reflected return light is reflected by the tilt detection unit having the angle detection optical system. The three-dimensional position and orientation detection sensor according to claim 2, wherein the three-dimensional position and orientation of the measurement object are calculated by measuring the inclination of the object around the vertical direction with three axes and six degrees of freedom.

The angle detection optical system comprises a low aberration lens, and is installed so that the light receiving surface of the position detection element is perpendicular to the optical axis of the lens and the center thereof is at the focal position of the lens. The three-dimensional position and orientation detection sensor according to claim 1, 2, or 3.

As the position detection element, a light receiving element that is detected by spatially separating carriers generated by incident spot light is used, and when detecting the center of gravity of the received light spot position, a spot having a predetermined received light amount level or higher The three-dimensional position and orientation detection sensor according to claim 1, wherein the position information of the measurement region is detected by detecting an image and using the position of the center of gravity obtained from the intensity information and the geometric shape as the light spot position information.

A light source having a predetermined different wavelength is used for the illumination light beam for posture angle detection and the irradiation light beam for position detection. The three-dimensional position and orientation detection sensor according to claim 1, wherein the three-dimensional position and orientation detection sensor is inserted into an inclination detection unit, and the light output of the wavelength is made smaller than the other light output.