JP4429503B2

JP4429503B2 - 3D measurement method of virtual ridgeline

Info

Publication number: JP4429503B2
Application number: JP2000249984A
Authority: JP
Inventors: 卓士後藤
Original assignee: Sanyo Machine Works Ltd
Current assignee: Sanyo Machine Works Ltd
Priority date: 2000-08-21
Filing date: 2000-08-21
Publication date: 2010-03-10
Anticipated expiration: 2020-08-21
Also published as: JP2002062127A

Description

【０００１】
【発明の属する技術分野】
本発明は、金型等の測定対象物のコーナー部における仮想稜線の三次元座標を検出してＣＡＤデータ等と比較・評価する際の仮想稜線の三次元測定方法に関する。
【０００２】
【従来の技術】
自動車ボデーや金型等の測定対象物の製作工程に、この測定対象物の外形寸法をＣＣＤカメラ等の三次元測定装置で測定した測定データをコンピュータで数値計算して、測定対象物のＣＡＤデータと比較し評価することで、測定対象物の寸法精度等を評価する工程がある。例えば、測定対象物のコーナー部の仮想稜線を三次元測定装置で測定した測定データと、ＣＡＤデータの稜線部データを比較・評価して、測定対象物のコーナー部の寸法精度をＣＡＤデータに基づいて評価する工程がある。
【０００３】
図５に測定対象物１のコーナー部２を示すと、このコーナー部２を挟んで第１曲面３ａと第２曲面３ｂが隣接し、この両曲面３ａ、３ｂの図５破線で示す延長面が交差する交線（図５の鎖線）が仮想稜線４で、この仮想稜線４の三次元座標データを算出することでコーナー部２の寸法精度等の評価が行われる。第１曲面３ａと第２曲面３ｂは平面を含む曲面である。仮想稜線４の三次元座標データの算出は、図６或いは図７に示す要領で行われている。
【０００４】
図６は粘土１０で仮想稜線４を現出させている。測定対象物１のコーナー部２上に断面山形に粘土１０を盛り、粘土１０の両曲面が第１曲面３ａと第２曲面３ｂの延長面となるようにして、粘土１０の稜線１１が仮想稜線４と一致するようにしている。この粘土１０の稜線１１に携帯式の測定点指示具である例えば測定ツール２０の先端のプローブ２１を接触させ、測定ツール２０の上部に設けた複数の定点（発光点）の三次元座標を光学式三次元測定装置で測定し、同測定装置のコンピュータで数値計算することで、稜線１１の任意の１点の三次元座標データを求める。同様にして稜線１１の複数点の三次元座標データを求め、これら座標データを数値計算することで、測定対象物１の仮想稜線４の三次元座標データを算出する。この算出された座標データと前記コンピュータに予め格納されたＣＡＤデータの稜線部データと比較し、評価することで、測定対象物１のコーナー部２やその両曲面３ａ、３ｂの寸法精度等が評価される。
【０００５】
図７は、第１曲面３ａと第２曲面３ｂが略平面とした場合に両曲面３ａ、３ｂ上にそれぞれに離隔した２点Ａ₁、Ａ₂、Ｂ₁、Ｂ₂をサンプリングポイントとして設定し、各点Ａ₁、Ａ₂、Ｂ₁、Ｂ₂に上記同様の測定ツールのプローブ２１を順に当てることで各点Ａ₁、Ａ₂，Ｂ₁、Ｂ₂の三次元座標データを求めて、第１曲面３ａの２点Ａ₁、Ａ₂の座標データから第１曲面３ａの直線を定義し、第２曲面３ｂの２点Ｂ₁、Ｂ₂の座標データから第２曲面３ｂの直線を定義し、これら定義された２直線の交点座標を仮想稜線４上の１点の座標データとする。このようにして仮想稜線４の複数点の座標データを求めて、測定対象物１の仮想稜線４の三次元座標データを算出し、これをコンピュータに予め格納されたＣＡＤデータの稜線部データと比較し評価することで、測定対象物１の寸法精度等が評価される。
【０００６】
また、第１曲面３ａと第２曲面３ｂが平面でない凸曲面の場合は、両曲面３ａ、３ｂのサンプリングポイントを３点以上の多数点にして、この多数点のサンプリングポイントの位置座標データから両曲面３ａ、３ｂの曲線を定義し、定義された２曲線の交点の位置座標から仮想稜線４の三次元座標データを算出することが行われている。
【０００７】
【発明が解決しようとする課題】
図６の粘土を使用した仮想稜線の三次元測定方法は、測定対象物に粘土を正確に盛り付ける作業と、粘土を取り除く作業が工数が多くて作業性が悪い。また、粘土を盛り付ける作業員の熟練度で仮想稜線の測定精度が左右されて、測定精度が安定しない。さらに、測定対象物の寸法形状によっては、仮想稜線を測定する部分であるコーナー部に粘土を盛り付けることが難しくなる場合が多くて、自由度や汎用性に欠ける。また、粘度に測定子をあてると粘度の部分が変形し、正確な測定ができないおそれがある。
【０００８】
図７に示す仮想稜線の三次元測定方法は、測定対象物のコーナー部を挟む両曲面に２点以上のサンプリングポイントが設定できれば、高精度な三次元測定が可能であり、この種の測定方法は各種の寸法形状の測定対象物に適用できる。ところが、測定対象物のコーナー部を挟む両曲面のそれぞれ２箇所以上をサンプリングポイントとして設定し、サンプリングした各箇所に測定ツール等を手動で移動させて、各サンプリングポイントを順番に測定するために、１つの仮想稜線の三次元測定の作業工数が多くなり、作業性の改善が難しい。
【０００９】
本発明の目的は、測定対象物のコーナー部を挟む両曲面の仮想稜線の三次元座標データを工数を少なくして作業性よく算出する三次元測定方法を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の仮想稜線の三次元測定方法は、測定対象物のコーナー部を挟んで隣接する第１曲面及び第２曲面の各々に測定点指示具の先端に離隔させて設置した測定子を同時に当接させて各測定子の三次元座標データをコンピュータで算出してサンプリングし、得られた測定子の三次元座標データと前記コンピュータに予め格納された測定対象物のＣＡＤデータに基づいて、前記第１曲面と第２曲面をコーナー部側に延長させた延長面の仮想交線である仮想稜線上の点の座標データを算出するものであって、次のステップを包含することを特徴とする。
測定点指示具（３０）の測定子（３３ａ、３３ｂ）の球中心（Ｐａ、Ｐｂ）と測定点指示具（３０）の本体部（３１）にある発光点（３４）の間の距離を既知データとしてコンピュータ（５０）に格納した測定点指示具（３０）を用いて測定対象物（１）のコーナー部（２）の仮想稜線（４）の測定を行うにあたり、
第１測定子（３３ａ）と第２測定子（３３ｂ）をコーナー部（２）の両側の第１曲面（３ａ）と第２曲面（３ｂ）に同時に当て、このときの測定点指示具（３０）の本体部（３１）を複数の撮像装置（４０）で撮像して画像データをコンピュータ（５０）に送り、
前記コンピュータ（５０）で、本体部（３１）の複数の発光点（３４）の三次元座標データを算出し、この座標データに基づいて第１測定子（３３ａ）と第２測定子（３３ｂ）の中心点座標を算出し、算出した座標データと発光点（３４）の三次元座標データを数値計算することにより、測定子（３３ａ、３３ｂ）の球中心（Ｐａ、Ｐｂ）の三次元座標データを算出し、
一方、前記コンピュータ（５０）に、ＣＡＤデータの第１ＣＡＤ曲面（Ｃａ）、第２ＣＡＤ曲面（Ｃｂ）及びＣＡＤコーナー面（Ｃｃ）の面データを格納しておき、
測定子（３３ａ、３３ｂ）が測定対象物（１）の両曲面（３ａ、３ｂ）に同時に接触して、各々の球中心（Ｐａ、Ｐｂ）の三次元座標データが求まると、この球中心（Ｐａ、Ｐｂ）を対応するＣＡＤ曲面（Ｃａ、Ｃｂ）に直交方向から投影した投影点（Ｑａ、Ｑｂ）の三次元座標データを算出し、
前記球中心（Ｐａ、Ｐｂ）とそれらの投影点（Ｑａ、Ｑｂ）の４点から断平面を定義し、
前記球中心（Ｐａ）と前記投影点（Ｑａ）を結ぶ直線上で前記球中心（Ｐａ）から前記測定子の半径分だけ離れた位置の点（Ｍａ）を求め、両者（Ｍａ、Ｑａ）から曲面（３ａ）での誤差（ベクトルｅａ）を算出し、
前記球中心（Ｐｂ）と前記投影点（Ｑｂ）を結ぶ直線上で前記球中心（Ｐｂ）から前記測定子の半径分だけ離れた位置の点（Ｍｂ）を求め、両者（Ｍｂ、Ｑｂ）から曲面（３ｂ）での誤差（ベクトルｅｂ）を算出し、
ベクトルｅａとベクトルｅｂを加算し、断平面上での仮想稜線のＣＡＤデータからの誤差（ベクトルｅ）として１点（４）の位置座標データを求める。
【００１１】
本発明の請求項２に記載の仮想稜線の三次元測定方法は、請求項１に記載の仮想稜線の三次元測定方法において、前記サンプリング測定動作をコーナー部の方向に測定点指示具を相対移動させて複数のサンプリング箇所で行い、複数のサンプリング箇所から得られた測定子の三次元座標データと前記コンピュータに予め格納された測定対象物のＣＡＤデータに基づいて、第１曲面と第２曲面をコーナー部側に延長させた延長面の仮想交線である仮想稜線の座標データを算出することを特徴とする。
【００１２】
本発明の請求項３に記載の仮想稜線の三次元測定方法は、請求項１または２に記載の仮想稜線の測定方法において、上記２個の測定子の三次元座標データを測定対象物のＣＡＤデータと比較・評価することで仮想稜線のＣＡＤデータに対するずれ量を算出することを特徴とする。
【００１３】
ここで、上記ＣＡＤデータは、製作される測定対象物の設計段階でのコーナー部とその両曲面の三次元座標データで、本発明はこのＣＡＤデータを利用することで測定対象物の仮想稜線の座標データが正確に、簡単に得られるようにしている。また、２個の測定子の座標データのＣＡＤデータに対するずれ量を算出することで、製作段階に在る測定対象物の寸法精度が高信頼度で評価される。
【００１４】
本発明の請求項４に記載の仮想稜線の三次元測定方法は、請求項１または２に記載の仮想稜線の三次元測定方法において、上記測定点指示具の先端に３個以上の測定子を相互に離隔させて設置し、測定対象物のコーナー部の形状に適合する２個の測定子を選択して使用することを特徴とする。
【００１５】
ここで、測定点指示具は、先端に２個以上の測定子を有する携帯式測定ツールを使用すればよい。このような測定点指示具は、上部に設置された３点以上の発光点が遠方の光学式三次元測定装置（ＣＣＤカメラ等）のコンピュータで読み取られる光学式測定ツールや、多関節型アーム等をもつ機械式の三次元測定装置に付属の測定ツールが適用される。また、２個以上の測定子は同一半径の球体が望ましいが、その形状と大きさは限定されない。
【００１６】
【発明の実施の形態】
図５の測定対象物１の仮想稜線４の本発明方法による測定実施形態例を、図１乃至図４を参照して説明する。
【００１７】
図１に示される測定点指示具３０は、片手で操作される携帯式の光学式測定ツールで、先端に２個以上の測定子３３ａ、…を有する。測定点指示具３０は片手で持たれる本体部３１と、本体部３１の下端に突出するプローブ部３２を有する。複数の定箇所に発光ダイオード等の発光点３４，…が設置される。プローブ部３２の先端部が複数本に枝分かれして、枝分かれした各先端部に測定子３３ａ、…が１個ずつ連結される。測定点指示具３０の具体例を図４に示すと、同図の測定点指示具３０は先端に５個の測定子３３ａ〜３３ｅを有し、各測定子３３ａ〜３３ｅは互いに離隔して設置された例えば同一半径の球体（スタイラス球）である。測定点指示具３０で測定対象物１の仮想稜線４を測定する場合、図１に示すように５個の測定子３３ａ〜３３ｅのいずれか２個が選択されて使用される。尚、図１においては使用される２個の測定子だけが図示され、この２個を例えば第１測定子３３ａと第２測定子３３ｂとする。
【００１８】
測定対象物１のコーナー部２の仮想稜線４の測定に際して、測定点指示具３０の５個の測定子３３ａ〜３３ｅの内のコーナー部２の寸法形状に最も合う２個が選択され、選択された２個の第１測定子３３ａ及び第２測定子３３ｂがコーナー部２の両側の第１曲面３ａ及び第２曲面３ｂの各１点のサンプリングポイントに同時に当てられ、このときの測定点指示具３０の本体部３１が複数台のＣＣＤカメラ等の撮像装置４０で撮像され、撮像された画像データがコンピュータ５０に送られる。
【００１９】
コンピュータ５０は、本体部３１の複数点の発光点３４、…の三次元座標データを算出し、この座標データに基づいて２個の第１測定子３３ａと第２測定子３３ｂの中心点座標を算出する。即ち、図２に示すように測定対象物１の両曲面３ａ、３ｂに同時に当接させた２個の測定子３３ａ、３３ｂの球中心Ｐａ，Ｐｂと、測定点指示具３０の定点にある発光点３４，…の距離が既知データとしてコンピュータ５０に格納され、この既知データと発光点３４，…の三次元座標データを数値計算することで、２個の測定子３３ａ、３３ｂの球中心Ｐａ，Ｐｂの三次元座標データが算出される。
【００２０】
一方でコンピュータ５０に、図２鎖線で示すＣＡＤデータの第１ＣＡＤ曲面Ｃａ、第２ＣＡＤ曲面Ｃｂ及びＣＡＤコーナー面Ｃｃの面データを格納しておく。２個の測定子３３ａ、３３ｂが測定対象物１の両曲面３ａ、３ｂの各１点のサンプリングポイントに同時に接触して、各々の球中心Ｐａ，Ｐｂの三次元座標データが求まると、この球中心Ｐａ、Ｐｂを対応するＣＡＤ曲面Ｃａ、Ｃｂに直交方向から投影した投影点Ｑａ、Ｑｂの三次元座標データを算出する。そして、図３に示すように２点の球中心Ｐａ、Ｐｂと２点の投影点Ｑａ、Ｑｂの４点から断平面を定義する。測定子３３ａの中心Ｐａと投影点Ｑａを結ぶ直線上で点Ｐａから測定子の半径分だけ離れた位置の点Ｍａが求まり、曲面３ａでの誤差（ベクトルｅa）がＭａ、Ｑａから算出される。曲面３ｂについても同様にして誤差（ベクトルｅｂ）が算出される。したがって、断平面上での仮想稜線のＣＡＤデータからの誤差（ベクトルｅ）は、ベクトルｅａ＋ベクトルｅｂで算出され、1点の位置座標データが求まる。
【００２１】
以上の両曲面３ａ、３ｂのサンプリング動作が、図１の測定点指示具３０をコーナー部２の方向に倣わせて複数の離隔したサンプリングポイントＳ₁、Ｓ₂、…で順に行われて、仮想稜線４の三次元座標データが算出される。測定対象物１の両曲面３ａ、３ｂの座標データとＣＡＤ曲面Ｃａ、ＣｂのＣＡＤデータで曲面間のずれ量が算出され、両ＣＡＤ曲面Ｃａ、Ｃｂの延長面が交差するＣＡＤ仮想稜線Ｃｄと測定対象物１の仮想稜線４の座標データから両者仮想稜線Ｃｄと４のずれ量Ｄｘが算出される。このようなずれ量の有無、大小を評価することで測定対象物１のコーナー部２と両曲面３ａ、３ｂの寸法精度等が高精度で評価される。
【００２２】
以上の仮想稜線測定方法において使用される測定点指示具３０の２個の測定子３３ａ、３３ｂは、半径の異なる球体であってもよい。また、測定点指示具３０に５個の測定子３３ａ〜３３ｅを間隔や方向性を相違させて設置して、測定対象物１のコーナー部２の大きさや仮想稜線方向に合わせて最も適合する２個の測定子を使用するようにすれば、測定点指示具３０の手動による倣い操作が常に良好な条件下で行えるようになり、仮想稜線の三次元測定作業の作業性がより改善される。また、以上の実施形態は光学式測定点指示具３０を使用しているが、この種の測定点指示具は機械式の三次元測定装置に付属の測定点指示具を使用することも可能である。
【００２３】
【発明の効果】
本発明によれば、測定対象物のコーナー部を挟む両曲面に測定点指示具の２個の測定子を同時に当接させて両曲面の各１点のサンプリングポイントの座標データを求め、コーナー部における仮想稜線の三次元座標データをコンピュータで算出するようにしたので、１つの仮想稜線の測定作業が１つの測定点指示具をコーナー部に倣わすだけの工数少ない簡単な作業で実施できて、作業性の大幅な改善が図れる。
【００２４】
また、測定点指示具の先端に３個以上の測定子を相互に離隔させて設置して、測定対象物のコーナー部の形状寸法、方向性に最も適合した２個の測定子を選択して使用することで、測定対象物のコーナー部を挟む両曲面に２個の測定子を手動でより移動させ易いように操作することができて、仮想稜線測定の手動で行なわれる作業行程の作業性が尚一層に改善される。
【図面の簡単な説明】
【図１】本発明方法の実施形態を示す測定対象物と測定点指示具の斜視図。
【図２】図１における２個の測定子とＣＡＤデータ曲面の関係を示す斜視図。
【図３】図１における２個の測定子とＣＡＤデータ曲面と測定対象物曲面の関係を示す断面図。
【図４】仮想稜線測定に使用する測定点指示具の一例を示す斜視図。
【図５】測定対象物のコーナー部の斜視図。
【図６】図５の測定対象物の従来方法による仮想稜線測定方法を説明するための斜視図。
【図７】図５の測定対象物の他の従来方法による仮想稜線測定方法を説明するための斜視図。
【符号の説明】
１測定対象物
２コーナー部
３ａ第１曲面
３ｂ第２曲面
４仮想稜線
３０測定点指示具
３３測定子
３３ａ、３３ｂ（使用する２個の）測定子
５０コンピュータ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a three-dimensional measurement method of a virtual ridge line when detecting a three-dimensional coordinate of a virtual ridge line at a corner portion of a measurement object such as a mold and comparing / evaluating it with CAD data or the like.
[0002]
[Prior art]
In the manufacturing process of measurement objects such as automobile bodies and molds, the measurement data obtained by measuring the external dimensions of this measurement object with a three-dimensional measuring device such as a CCD camera is numerically calculated by a computer, and CAD data of the measurement object is obtained. There is a step of evaluating the dimensional accuracy and the like of the measurement object by comparing and evaluating. For example, the measurement data obtained by measuring the virtual ridgeline at the corner of the measurement object with a three-dimensional measuring device and the ridgeline data of the CAD data are compared and evaluated, and the dimensional accuracy of the corner of the measurement object is based on the CAD data. There is a process to evaluate.
[0003]
When the corner part 2 of the measuring object 1 is shown in FIG. 5, the first curved surface 3a and the second curved surface 3b are adjacent to each other with the corner part 2 interposed therebetween, and the extended surfaces indicated by broken lines in FIG. The intersecting intersecting line (chain line in FIG. 5) is the virtual ridgeline 4, and the three-dimensional coordinate data of the virtual ridgeline 4 is calculated to evaluate the dimensional accuracy and the like of the corner portion 2. The first curved surface 3a and the second curved surface 3b are curved surfaces including a plane. The calculation of the three-dimensional coordinate data of the virtual ridgeline 4 is performed as shown in FIG. 6 or FIG.
[0004]
In FIG. 6, the virtual ridgeline 4 is made to appear with the clay 10. The clay 10 is piled up in a cross-sectional mountain shape on the corner 2 of the measurement object 1, and both the curved surfaces of the clay 10 are extended surfaces of the first curved surface 3a and the second curved surface 3b, and the ridge line 11 of the clay 10 is a virtual ridge line. 4 is matched. For example, the probe 21 at the tip of the measurement tool 20 which is a portable measurement point indicating tool is brought into contact with the ridge line 11 of the clay 10, and the three-dimensional coordinates of a plurality of fixed points (light emission points) provided on the upper part of the measurement tool 20 are optically measured. The three-dimensional coordinate data of one arbitrary point of the ridge line 11 is obtained by measuring with an equation type three-dimensional measuring apparatus and numerically calculating with a computer of the measuring apparatus. Similarly, three-dimensional coordinate data of a plurality of points of the ridge line 11 is obtained, and the three-dimensional coordinate data of the virtual ridge line 4 of the measurement object 1 is calculated by numerically calculating these coordinate data. By comparing and evaluating the calculated coordinate data and the edge data of CAD data stored in advance in the computer, the dimensional accuracy and the like of the corner portion 2 of the measurement object 1 and its curved surfaces 3a and 3b are evaluated. Is done.
[0005]
In FIG. 7, when the first curved surface 3a and the second curved surface 3b are substantially flat, two points A ₁ , A ₂ , B ₁ , B ₂ separated from each other on the curved surfaces 3a, 3b are set as sampling points. , seeking three-dimensional coordinate data of each point _{_{_{a 1, a 2, B 1}}} , B 2 in the same manner as described above for each point a ₁ in order shed that the probe 21 of the measuring _{_{tool, a 2, B 1, B}} 2, The straight line of the first curved surface 3a is defined from the coordinate data of the two points A ₁ and A ₂ of the first curved surface 3a, and the straight line of the second curved surface 3b is defined from the coordinate data of the two points B ₁ and B ₂ of the second curved surface 3b. Then, the intersection coordinates of these two defined straight lines are set as the coordinate data of one point on the virtual ridgeline 4. In this way, the coordinate data of a plurality of points of the virtual ridgeline 4 is obtained, the three-dimensional coordinate data of the virtual ridgeline 4 of the measurement object 1 is calculated, and this is compared with the ridgeline part data of CAD data stored in advance in the computer. Then, the dimensional accuracy and the like of the measurement object 1 are evaluated.
[0006]
In the case where the first curved surface 3a and the second curved surface 3b are convex surfaces, the sampling points of both curved surfaces 3a and 3b are set to a large number of three or more points, and both are obtained from the position coordinate data of the sampling points of the multiple points. The curved surfaces 3a and 3b are defined, and the three-dimensional coordinate data of the virtual ridge line 4 is calculated from the position coordinates of the intersection of the two defined curves.
[0007]
[Problems to be solved by the invention]
In the three-dimensional measuring method of the virtual ridgeline using the clay of FIG. 6, the work of accurately placing the clay on the measurement object and the work of removing the clay have many man-hours and the workability is poor. In addition, the measurement accuracy of the virtual ridge line depends on the skill level of the worker placing clay, and the measurement accuracy is not stable. Furthermore, depending on the size and shape of the object to be measured, it is often difficult to place clay on the corner portion, which is a portion for measuring the virtual ridgeline, and lacks flexibility and versatility. Moreover, if a probe is applied to the viscosity, the viscosity portion is deformed, and there is a possibility that accurate measurement cannot be performed.
[0008]
The virtual ridge line three-dimensional measurement method shown in FIG. 7 is capable of high-precision three-dimensional measurement if two or more sampling points can be set on both curved surfaces sandwiching the corner portion of the measurement object. Can be applied to measurement objects of various dimensions and shapes. However, in order to measure each sampling point in order by setting two or more of the two curved surfaces sandwiching the corner portion of the measurement object as sampling points, manually moving the measurement tool etc. to each sampled location, The work man-hour for the three-dimensional measurement of one virtual ridgeline increases, and it is difficult to improve workability.
[0009]
An object of the present invention is to provide a three-dimensional measurement method for calculating three-dimensional coordinate data of virtual ridge lines of both curved surfaces sandwiching a corner portion of an object to be measured with reduced man-hours and good workability.
[0010]
[Means for Solving the Problems]
Three-dimensional measuring method of virtual ridge of the invention, the measuring stator that is installed by spaced distal end of the measurement points the pointing device in each of the first curved surface and second curved surface adjacent to each other across the corner portion of the measurement object At the same time, the three-dimensional coordinate data of each probe is calculated and sampled by a computer, and based on the obtained three-dimensional coordinate data of the probe and the CAD data of the measurement object stored in advance in the computer, Coordinate data of a point on a virtual ridge line that is a virtual intersection line of an extended surface obtained by extending the first curved surface and the second curved surface to the corner portion side, and includes the following steps: To do.
The distance between the sphere center (Pa, Pb) of the probe (33a, 33b) of the measuring point indicator (30) and the light emitting point (34) in the main body (31) of the measuring point indicator (30) is known. When measuring the virtual ridgeline (4) of the corner part (2) of the measurement object (1) using the measurement point indicating tool (30) stored in the computer (50) as data,
The first measuring element (33a) and the second measuring element (33b) are simultaneously applied to the first curved surface (3a) and the second curved surface (3b) on both sides of the corner portion (2), and the measuring point indicating tool (30 at this time) ) Of the main body (31) with a plurality of imaging devices (40) to send image data to the computer (50),
The computer (50) calculates three-dimensional coordinate data of a plurality of light emitting points (34) of the main body (31), and based on the coordinate data, the first measuring element (33a) and the second measuring element (33b). Is calculated, and the calculated coordinate data and the three-dimensional coordinate data of the light emitting point (34) are numerically calculated, whereby the three-dimensional coordinate data of the spherical center (Pa, Pb) of the probe (33a, 33b) is calculated. To calculate
On the other hand, the computer (50) stores the surface data of the first CAD curved surface (Ca), the second CAD curved surface (Cb) and the CAD corner surface (Cc) of the CAD data,
When the stylus (33a, 33b) simultaneously contacts both curved surfaces (3a, 3b) of the measurement object (1) and the three-dimensional coordinate data of each sphere center (Pa, Pb) is obtained, this sphere center ( Calculating three-dimensional coordinate data of projection points (Qa, Qb) obtained by projecting Pa, Pb) onto the corresponding CAD curved surface (Ca, Cb) from the orthogonal direction;
A section plane is defined from four points of the sphere center (Pa, Pb) and their projection points (Qa, Qb),
A point (Ma) at a position separated from the sphere center (Pa) by the radius of the measuring element on a straight line connecting the sphere center (Pa) and the projection point (Qa) is obtained, and from both (Ma, Qa) Calculate the error (vector ea) on the curved surface (3a),
A point (Mb) at a position separated from the sphere center (Pb) by the radius of the measuring element on the straight line connecting the sphere center (Pb) and the projection point (Qb) is obtained, and from both (Mb, Qb) Calculate the error (vector eb) on the curved surface (3b),
The vector ea and the vector eb are added, and the position coordinate data of one point (4) is obtained as an error (vector e) from the CAD data of the virtual ridge line on the section plane.
[0011]
The virtual ridge line three-dimensional measuring method according to claim 2 of the present invention is the virtual ridge line three-dimensional measuring method according to claim 1, wherein the sampling point measurement tool is relatively moved in the direction of the corner portion. The first curved surface and the second curved surface are obtained based on the three-dimensional coordinate data of the probe obtained from the plurality of sampling locations and the CAD data of the measuring object stored in advance in the computer. Coordinate data of a virtual ridge line that is a virtual intersection line of the extended surface extended to the corner portion side is calculated.
[0012]
The virtual ridge line three-dimensional measuring method according to claim 3 of the present invention is the virtual ridge line measuring method according to claim 1 or 2, wherein the three-dimensional coordinate data of the two measuring elements is CAD of the measurement object. A deviation amount of the virtual ridge line with respect to the CAD data is calculated by comparing and evaluating the data.
[0013]
Here, the CAD data is the three-dimensional coordinate data of the corner portion and both curved surfaces at the design stage of the measurement object to be manufactured, and the present invention uses this CAD data to determine the virtual ridgeline of the measurement object. Coordinate data can be obtained accurately and easily. Further, by calculating the amount of deviation of the coordinate data of the two measuring elements from the CAD data, the dimensional accuracy of the measurement object in the manufacturing stage is evaluated with high reliability.
[0014]
The virtual ridge line three-dimensional measuring method according to claim 4 of the present invention is the virtual ridge line three-dimensional measuring method according to claim 1 or 2, wherein three or more measuring elements are provided at the tip of the measuring point indicating tool. It is characterized in that two measuring elements that are installed to be separated from each other and conform to the shape of the corner portion of the measuring object are selected and used.
[0015]
Here, as the measuring point indicating tool, a portable measuring tool having two or more measuring elements at the tip may be used. Such a measuring point indicating tool includes an optical measuring tool that can be read by a computer of an optical three-dimensional measuring device (CCD camera or the like) that has three or more light emitting points installed on the top, an articulated arm, etc. The attached measurement tool is applied to a mechanical three-dimensional measuring apparatus having The two or more measuring elements are preferably spheres having the same radius, but the shape and size are not limited.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
A measurement embodiment example of the virtual ridgeline 4 of the measurement object 1 in FIG. 5 according to the method of the present invention will be described with reference to FIGS. 1 to 4.
[0017]
A measurement point indicating tool 30 shown in FIG. 1 is a portable optical measurement tool operated with one hand, and has two or more measuring elements 33a at the tip. The measurement point indicating tool 30 has a main body part 31 held by one hand and a probe part 32 protruding from the lower end of the main body part 31. Light emitting points 34,... Such as light emitting diodes are installed at a plurality of fixed locations. The tip portion of the probe portion 32 is branched into a plurality of pieces, and one measuring element 33a,... Is connected to each branched tip portion. FIG. 4 shows a specific example of the measurement point indicating tool 30. The measuring point indicating tool 30 in FIG. 4 has five measuring elements 33a to 33e at the tip, and the measuring elements 33a to 33e are spaced apart from each other. For example, a sphere (stylus sphere) having the same radius. When measuring the virtual ridgeline 4 of the measuring object 1 with the measuring point indicating tool 30, any two of the five measuring elements 33a to 33e are selected and used as shown in FIG. In FIG. 1, only two measuring elements to be used are shown, and these two elements are, for example, a first measuring element 33a and a second measuring element 33b.
[0018]
When measuring the virtual ridge line 4 of the corner portion 2 of the measurement object 1, two of the five measuring elements 33a to 33e of the measurement point indicating tool 30 that best match the size and shape of the corner portion 2 are selected and selected. Two first measuring elements 33a and second measuring elements 33b are simultaneously applied to one sampling point on each of the first curved surface 3a and the second curved surface 3b on both sides of the corner portion 2, and the measuring point indicating tool at this time The 30 main body portions 31 are imaged by an imaging device 40 such as a plurality of CCD cameras, and the captured image data is sent to the computer 50.
[0019]
The computer 50 calculates three-dimensional coordinate data of a plurality of light emitting points 34,... Of the main body 31, and based on the coordinate data, the center point coordinates of the two first measuring elements 33a and second measuring elements 33b are calculated. calculate. That is, as shown in FIG. 2, the light emission at the fixed points of the measuring point indicating tool 30 and the spherical centers Pa and Pb of the two measuring elements 33 a and 33 b simultaneously brought into contact with both the curved surfaces 3 a and 3 b of the measuring object 1. The distance between the points 34,... Is stored in the computer 50 as known data, and the three-dimensional coordinate data of the known data and the light emitting points 34,. Pb three-dimensional coordinate data is calculated.
[0020]
On the other hand, the computer 50 stores the surface data of the first CAD curved surface Ca, the second CAD curved surface Cb, and the CAD corner surface Cc of the CAD data indicated by chain lines in FIG. When the two measuring elements 33a and 33b are simultaneously brought into contact with one sampling point of each of the curved surfaces 3a and 3b of the measuring object 1, and the three-dimensional coordinate data of the respective spherical centers Pa and Pb are obtained, The three-dimensional coordinate data of the projection points Qa and Qb obtained by projecting the centers Pa and Pb onto the corresponding CAD curved surfaces Ca and Cb from the orthogonal direction is calculated. Then, as shown in FIG. 3, a section plane is defined from the four points of the two spherical centers Pa and Pb and the two projected points Qa and Qb. On the straight line connecting the center Pa of the probe 33a and the projection point Qa, a point Ma at a position separated from the point Pa by the radius of the probe is obtained, and an error (vector ea) on the curved surface 3a is calculated from Ma and Qa. . Similarly, an error (vector eb) is calculated for the curved surface 3b. Therefore, the error (vector e) from the CAD data of the virtual ridgeline on the cut plane is calculated as vector ea + vector eb, and the position coordinate data of one point is obtained.
[0021]
The sampling operation of both the curved surfaces 3a and 3b is performed in order at a plurality of spaced sampling points S ₁ , S ₂ ,... By following the measurement point indicating tool 30 of FIG. Three-dimensional coordinate data of the ridgeline 4 is calculated. A deviation amount between the curved surfaces is calculated from the coordinate data of the two curved surfaces 3a and 3b of the measurement object 1 and the CAD data of the CAD curved surfaces Ca and Cb, and measurement is performed with the CAD virtual ridge line Cd where the extended surfaces of the CAD curved surfaces Ca and Cb intersect. A deviation amount Dx between the virtual ridge lines Cd and 4 is calculated from the coordinate data of the virtual ridge line 4 of the object 1. By evaluating the presence / absence and size of such a deviation amount, the dimensional accuracy and the like of the corner portion 2 and both curved surfaces 3a and 3b of the measurement object 1 are evaluated with high accuracy.
[0022]
The two measuring elements 33a and 33b of the measuring point indicating tool 30 used in the above virtual ridge line measuring method may be spheres having different radii. In addition, five measuring elements 33a to 33e are installed on the measuring point indicating tool 30 with different intervals and directivity, and the most suitable 2 according to the size of the corner portion 2 and the virtual ridge line direction of the measuring object 1. If a single probe is used, the manual scanning operation of the measurement point indicating tool 30 can always be performed under favorable conditions, and the workability of the three-dimensional measurement operation of the virtual ridge line is further improved. In the above embodiment, the optical measurement point indicator 30 is used. However, this type of measurement point indicator can also use a measurement point indicator attached to a mechanical three-dimensional measuring apparatus. is there.
[0023]
【The invention's effect】
According to the present invention, the two measuring elements of the measuring point indicating tool are simultaneously brought into contact with both curved surfaces sandwiching the corner portion of the measurement object to obtain the coordinate data of the sampling points of one point on both curved surfaces, and the corner portion. Since the three-dimensional coordinate data of the virtual ridge line in the computer is calculated by the computer, the measurement work of one virtual ridge line can be carried out with a simple work with few man-hours to imitate one measurement point indicating tool, Workability can be greatly improved.
[0024]
Also, install three or more measuring elements at the tip of the measuring point indicator and select the two measuring elements that best fit the shape and direction of the corner of the measurement object. By using it, it is possible to operate the two measuring elements on both curved surfaces sandwiching the corner portion of the measurement object so that it can be easily moved manually, and the workability of the work process performed manually for the virtual ridge line measurement is improved. Is further improved.
[Brief description of the drawings]
FIG. 1 is a perspective view of a measurement object and a measurement point indicating tool showing an embodiment of the method of the present invention.
FIG. 2 is a perspective view showing a relationship between two measuring elements and a CAD data curved surface in FIG. 1;
FIG. 3 is a cross-sectional view showing the relationship between two measuring elements, a CAD data curved surface, and a measuring object curved surface in FIG. 1;
FIG. 4 is a perspective view showing an example of a measurement point indicating tool used for virtual ridge line measurement.
FIG. 5 is a perspective view of a corner portion of a measurement object.
6 is a perspective view for explaining a virtual ridge line measuring method according to the conventional method of the measuring object of FIG. 5;
7 is a perspective view for explaining a virtual ridge line measuring method according to another conventional method of the measuring object of FIG. 5. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Measuring object 2 Corner part 3a 1st curved surface 3b 2nd curved surface 4 Virtual ridgeline 30 Measuring point indicator 33 Measuring element 33a, 33b Measuring element 50 (two used) Measuring element 50 Computer

Claims

First curved surface and second curved surface each three-dimensional coordinate data of each measuring element by spaced distal end of the measurement points the pointing device is simultaneously abut installed was measured stator and with the adjacent sides of the corner portion of the measurement object Is calculated and sampled by a computer, and the first curved surface and the second curved surface are arranged on the corner side based on the obtained three-dimensional coordinate data of the probe and CAD data of the measurement object stored in the computer in advance. A three-dimensional measuring method of a virtual ridge line which calculates coordinate data of a point on a virtual ridge line which is a virtual intersection line of an extended surface, and includes the following steps .
The distance between the sphere center (Pa, Pb) of the probe (33a, 33b) of the measuring point indicator (30) and the light emitting point (34) in the main body (31) of the measuring point indicator (30) is known. When measuring the virtual ridgeline (4) of the corner part (2) of the measurement object (1) using the measurement point indicating tool (30) stored in the computer (50) as data,
The first measuring element (33a) and the second measuring element (33b) are simultaneously applied to the first curved surface (3a) and the second curved surface (3b) on both sides of the corner portion (2), and the measuring point indicating tool (30 at this time) ) Of the main body (31) with a plurality of imaging devices (40) to send image data to the computer (50),
The computer (50) calculates three-dimensional coordinate data of a plurality of light emitting points (34) of the main body (31), and based on the coordinate data, the first measuring element (33a) and the second measuring element (33b). Is calculated, and the calculated coordinate data and the three-dimensional coordinate data of the light emitting point (34) are numerically calculated, whereby the three-dimensional coordinate data of the spherical center (Pa, Pb) of the probe (33a, 33b) is calculated. To calculate
On the other hand, the computer (50) stores the surface data of the first CAD curved surface (Ca), the second CAD curved surface (Cb) and the CAD corner surface (Cc) of the CAD data,
When the stylus (33a, 33b) simultaneously contacts both curved surfaces (3a, 3b) of the measurement object (1) and the three-dimensional coordinate data of each sphere center (Pa, Pb) is obtained, this sphere center ( Calculating three-dimensional coordinate data of projection points (Qa, Qb) obtained by projecting Pa, Pb) onto the corresponding CAD curved surface (Ca, Cb) from the orthogonal direction;
A section plane is defined from four points of the sphere center (Pa, Pb) and their projection points (Qa, Qb),
A point (Ma) at a position separated from the sphere center (Pa) by the radius of the measuring element on a straight line connecting the sphere center (Pa) and the projection point (Qa) is obtained, and from both (Ma, Qa) Calculate the error (vector ea) on the curved surface (3a),
A point (Mb) at a position separated from the sphere center (Pb) by the radius of the measuring element on the straight line connecting the sphere center (Pb) and the projection point (Qb) is obtained, and from both (Mb, Qb) Calculate the error (vector eb) on the curved surface (3b),
The vector ea and the vector eb are added, and the position coordinate data of one point (4) is obtained as an error (vector e) from the CAD data of the virtual ridge line on the section plane.

The sampling measurement operation is performed at a plurality of sampling locations by relatively moving the measurement point indicating tool in the direction of the corner portion, and the three-dimensional coordinate data of the probe obtained from the plurality of sampling locations and the measurement stored in advance in the computer 2. The coordinate data of a virtual ridge line, which is a virtual intersection line of an extended surface obtained by extending the first curved surface and the second curved surface toward a corner portion, is calculated based on CAD data of an object. 3D measurement method of virtual ridgeline.

The virtual ridgeline according to claim 1 or 2, wherein a displacement amount of the virtual ridgeline with respect to the CAD data is calculated by comparing and evaluating the three-dimensional coordinate data of the two measuring elements with the CAD data of the measurement object. 3D measurement method.

Three or more measuring elements are set apart from each other at the tip of the measuring point indicating tool, and two measuring elements that match the shape of the corner of the measuring object are selected and used. The three-dimensional measuring method of the virtual ridgeline according to claim 1 or 2.