JPH08272451A - Calibration method in robot with visual sensor - Google Patents
Calibration method in robot with visual sensorInfo
- Publication number
- JPH08272451A JPH08272451A JP7010895A JP7010895A JPH08272451A JP H08272451 A JPH08272451 A JP H08272451A JP 7010895 A JP7010895 A JP 7010895A JP 7010895 A JP7010895 A JP 7010895A JP H08272451 A JPH08272451 A JP H08272451A
- Authority
- JP
- Japan
- Prior art keywords
- position information
- calibration
- points
- visual sensor
- robot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、視覚センサを有する産
業用ロボットのキャリブレーション方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for calibrating an industrial robot having a visual sensor.
【０００２】[0002]
【従来の技術】視覚センサを有する産業用ロボットにお
いてキャリブレーションを行う場合、画像座標系上およ
び作業空間上の位置情報が３点分以上必要となる。従来
は、視覚センサを用いて３点の画像座標系上の位置情報
を認識させ、その３点にロボットの制御点を移動させて
作業空間上の位置情報を得て画像座標系と作業空間との
キャリブレーションを行っていた。ところが、多関節ロ
ボットは、剛性が低く、たわみ等をおこしやすく、ロボ
ットの設計上の寸法と実際のロボットが動いた場合の寸
法の食い違いが生じやすいため、従来の方法では、ロボ
ット各々の作業位置や姿勢により、計算上で到達する点
と、実際に到達する点との違いが生じ、キャリブレーシ
ョンに必要な作業空間上の位置情報に誤差が生じやすく
なるという問題があった。このような問題に対して、特
開昭６３−６１９０３号公報には、被位置検出物におけ
る３か所の所定位置に設けられ、同心状の中空部を有す
る大円の周囲に所定の規則にしたがって少なくとも４個
以上の小円を配設したキャリブレーションパターンをそ
れぞれ個々のカメラによって撮像し、自動的に前記カメ
ラのレンズ中心位置を算出し、また、射影変換によって
座標系の変換を行う三次元座標変換装置が記載されてい
る。2. Description of the Related Art When an industrial robot having a visual sensor is calibrated, position information on an image coordinate system and a work space is required for three points or more. Conventionally, a visual sensor is used to recognize position information of three points on an image coordinate system, and a control point of a robot is moved to the three points to obtain position information on a work space to obtain an image coordinate system and a work space. Was being calibrated. However, since the articulated robot has low rigidity and is liable to bend, it is easy to cause a discrepancy between the design dimensions of the robot and the dimensions when the actual robot moves. There is a problem that a point that is reached in calculation and a point that is actually reached are different depending on the posture and the posture, and an error is likely to occur in the position information on the work space required for calibration. In order to solve such a problem, Japanese Patent Laid-Open No. 63-61903 sets forth a predetermined rule around a great circle having concentric hollow portions which are provided at three predetermined positions in an object to be detected. Therefore, a calibration pattern in which at least four small circles are arranged is taken by each camera, the lens center position of the camera is automatically calculated, and the coordinate system is transformed by projective transformation. A coordinate transformation device is described.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、この従
来の技術では、４点以上の点から、キャリブレーション
平面を算出するものである。このため、算出結果が、比
較的大きな誤差を含むデータに影響され、精度が低くな
るという問題があった。そこで、本発明が解決すべき課
題は、より高い精度のキャリブレーションデータを得
て、これを基に、より高い精度でキャリブレーションを
行うことにある。However, in this conventional technique, the calibration plane is calculated from four or more points. Therefore, there is a problem that the calculation result is affected by the data including a relatively large error and the accuracy is lowered. Therefore, the problem to be solved by the present invention is to obtain calibration data with higher accuracy and perform calibration with higher accuracy based on this.
【０００４】[0004]
【課題を解決するための手段】前記課題を解決するた
め、本発明は、視覚センサ付き多関節ロボットシステム
におけるキャリブレーション方法において、４点以上の
作業空間上および画像座標系上の位置情報を得た後、作
業空間上の位置情報を元に作業空間上にこれらの点の回
帰平面を算出し、この平面に対する各点の作業空間上の
位置情報の残差を基準として４点以上の位置情報からキ
ャリブレーションに必要な数の点の位置情報を選択し、
選択したデータを基にキャリブレーションを行おうとす
るものである。In order to solve the above-mentioned problems, the present invention provides a calibration method in a multi-joint robot system with a visual sensor to obtain position information on a work space of four points or more and on an image coordinate system. After that, the regression plane of these points is calculated on the work space based on the position information on the work space, and the position information of four or more points is set based on the residual of the position information on the work space of each point with respect to this plane. Select the position information of the number of points required for calibration from
It is intended to perform calibration based on the selected data.
【０００５】[0005]
【作用】上記手段により、４点以上のキャリブレーショ
ンデータから、キャリブレーション平面に対して比較的
残差の小さい１つの直線上にない３点のデータを得る。By the above means, the data of three points which are not on one straight line with a relatively small residual with respect to the calibration plane are obtained from the calibration data of four points or more.
【０００６】[0006]
【実施例】以下、本発明の実施例を図に基づいて説明す
る。図１は本発明に係る方法の手順を示すフローチャー
ト、図２はロボットに視覚センサ１を取り付け、視覚セ
ンサ１で画像認識のパターン図２を捉えた場合の斜視
図、図３は視覚センサ１で画像認識のパターン図２を捉
えて得られる画像パターン図５である。また図４は、本
発明の方法を実行するための装置の構成を示すブロック
図である。図４において、１は視覚センサ、１０は視覚
センサ１で撮像された画像信号を画像処理する画像処理
部、１１はロボット、１２は画像処理部１０からの信号
とロボット１１からの位置情報に基づいて演算処理を行
う処理部、１３は処理部からの処理結果をロボット１１
の制御装置（図示せず）に出力する出力部である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart showing the procedure of the method according to the present invention, FIG. 2 is a perspective view when a visual sensor 1 is attached to a robot, and the visual sensor 1 captures an image recognition pattern FIG. 2. FIG. FIG. 6 is an image pattern diagram 5 obtained by capturing the image recognition pattern diagram 2. Further, FIG. 4 is a block diagram showing the configuration of an apparatus for executing the method of the present invention. In FIG. 4, reference numeral 1 is a visual sensor, 10 is an image processing unit that performs image processing of an image signal captured by the visual sensor 1, 11 is a robot, 12 is based on a signal from the image processing unit 10 and position information from the robot 11. And a processing unit 13 for performing arithmetic processing by using the processing result from the processing unit by the robot 11
This is an output unit for outputting to the control device (not shown).
【０００７】ここでは５点を使用する例を示す。まず、
ロボットの制御点２を５個の円形パターン４の重心に移
動させ、移動した点の作業空間上の位置情報 Ｐｒ［ｉ］＝（ｒｘ［ｉ］，ｒｙ［ｉ］，ｒｚ［ｉ］）
（ｉ＝１〜５） を記憶させる（ステップ１０）。次に、画像５内の５個
のパターンについて画像処理を行い、画像内の各パター
ンの重心の画像座標系の位置情報 Ｐｖ［ｉ］＝（ｖｘ［ｉ］，ｖｙ［ｉ］，ｖｚ［ｉ］）
（ｉ＝１〜５） を得る（ステップ２０）。ステップ１０で得た作業空間
上の位置情報より、回帰平面を算出する（ステップ３
０）。回帰平面を、 ｚ＝ａ＊ｘ＋ｂ＊ｙ＋ｃ としたとき、係数ａ，ｂ，ｃは、作業空間上の位置情報
ｒｘ［ｉ］，ｒｙ［ｉ］，ｒｚ［ｉ］より、 ａ＝（Ｓｙｙ＊Ｓｘｚ−Ｓｘｙ＊Ｓｙｚ）／｜Ｓ｜ ｂ＝（Ｓｘｘ＊Ｓｙｚ−Ｓｘｙ＊Ｓｘｚ）／｜Ｓ｜ ｃ＝Ａｚ−ａ＊Ａｘ−ｂ＊Ａｙ ただし、Here, an example using 5 points is shown. First,
The control point 2 of the robot is moved to the center of gravity of the five circular patterns 4, and the positional information of the moved point in the working space Pr [i] = (rx [i], ry [i], rz [i])
(I = 1 to 5) is stored (step 10). Next, image processing is performed on five patterns in the image 5, and position information Pv [i] = (vx [i], vy [i], vz [i] of the image center of gravity of each pattern in the image. ]))
(I = 1 to 5) is obtained (step 20). A regression plane is calculated from the position information on the work space obtained in step 10 (step 3
0). When the regression plane is z = a * x + b * y + c, the coefficients a, b, and c are a = (Syy *) from the position information rx [i], ry [i], and rz [i] on the work space. Sxx-Sxy * Syz) / | S | b = (Sxx * Syz-Sxy * Sxz) / | S | c = Az-a * Ax-b * Ay where
【数１】 と定まり回帰平面が求められる（ステップ３０）。[Equation 1] Then, a regression plane is obtained (step 30).
【０００８】ここで、作業空間上の位置情報と回帰平面
との残差ｅ［ｉ］は、 ｅ［ｉ］＝ｒｚ［ｉ］−（ａ＊ｒｘ［ｉ］＋ｂ＊ｒｙ
［ｉ］＋ｃ）（ｉ＝１〜５） で求められる（ステップ４０）。ステップ１０で得た作
業空間上の位置情報のうち、ステップ４０で得た残差の
比較的小さな３点を選択し、これをキャリブレーション
用のデータとして選択する（ステップ５０）。ステップ
５０で得た３点の作業空間上の位置情報と、ステップ２
０で得たこれに対応する３点の画像座標系の位置情報よ
り、画素のＸ方向のサイズＸsizeとＹ方向のサイズＹ
sizeを求める（ステップ６０）。画素サイズと作業空間
上及び画像座標系の位置情報より、画像座標系の位置情
報を作業空間上の位置情報に変換するマトリックスを求
める（ステップ７０）。このように、３点より多い数の
点の位置情報のうち回帰平面からの残差の小さい３点を
選択してキャリブレーションに用いるようにしたことに
より、データの精度を向上させることができる。Here, the residual e [i] between the position information on the working space and the regression plane is e [i] = rz [i]-(a * rx [i] + b * ry
[I] + c) (i = 1 to 5) (step 40). Of the positional information on the working space obtained in step 10, three points with relatively small residuals obtained in step 40 are selected and selected as calibration data (step 50). Position information on the three work spaces obtained in step 50 and step 2
From the position information of the image coordinate system of three points corresponding to this obtained by 0, the size X size of the pixel in the X direction and the size Y of the pixel in the Y direction.
Size is calculated (step 60). A matrix for converting the position information of the image coordinate system into the position information of the working space is obtained from the pixel size and the position information of the working space and the image coordinate system (step 70). As described above, the accuracy of data can be improved by selecting three points having a small residual difference from the regression plane from the positional information of the points greater than three and using them for the calibration.
【０００９】[0009]
【発明の効果】以上述べたように、本発明によれば、４
点以上のキャリブレーションデータから、キャリブレー
ション平面に対して比較的残差の小さいデータが得ら
れ、これに基づいてキャリブレーションを行うので、よ
り高い精度のキャリブレーションが可能となる。As described above, according to the present invention, 4
From the calibration data of the points or more, data with a relatively small residual error is obtained with respect to the calibration plane, and the calibration is performed based on this, so that it is possible to perform the calibration with higher accuracy.
【図１】 本発明実施例の概略フローチャートである。FIG. 1 is a schematic flowchart of an embodiment of the present invention.
【図２】 本発明実施例の説明図である。FIG. 2 is an explanatory diagram of an example of the present invention.
【図３】 本発明実施例を示す斜視図である。FIG. 3 is a perspective view showing an embodiment of the present invention.
【図４】 本発明の方法を実行するための装置の構成を
示すブロック図である。FIG. 4 is a block diagram showing the configuration of an apparatus for executing the method of the present invention.
１ 視覚センサ、２ ロボットの制御点、３ 画像認識
のパターン図、４ 円形パターン、５ 視覚センサで捉
えた画像認識のパターン図、１０ 画像処理部、１１
ロボット、１２ 処理部、１３ 出力部1 visual sensor, 2 robot control points, 3 image recognition pattern diagram, 4 circular pattern, 5 image recognition pattern diagram captured by the visual sensor, 10 image processing unit, 11
Robot, 12 processing unit, 13 output unit
フロントページの続き (72)発明者 中村 正夫 福岡県北九州市八幡西区黒崎城石２番１号 株式会社安川電機内Front page continued (72) Inventor Masao Nakamura 2-1, Kurosaki Shiroishi, Hachimansai-ku, Kitakyushu, Fukuoka Prefecture Yasukawa Electric Co., Ltd.
Claims (1)
におけるキャリブレーション方法において、 ４点以上の作業空間上および画像座標系上の位置情報を
得た後、作業空間上の位置情報を元に作業空間上にこれ
らの点の回帰平面を算出し、この平面に対する各点の作
業空間上の位置情報の残差を基準として４点以上の位置
情報からキャリブレーションに必要な数の点の位置情報
を選択し、選択したデータを基にキャリブレーションを
行うことを特徴とする視覚センサ付きロボットにおける
キャリブレーション方法。1. A calibration method in an articulated robot system with a visual sensor, wherein position information on a work space of four points or more and an image coordinate system is obtained, and then on the work space based on the position information on the work space. Then, calculate the regression plane of these points, and select the positional information of the number of points necessary for calibration from the positional information of four or more points with reference to the residual of the positional information of each point with respect to this plane. , A calibration method for a robot with a visual sensor, characterized in that calibration is performed based on selected data.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07010895A JP3541980B2 (en) | 1995-03-28 | 1995-03-28 | Calibration method for robot with visual sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP07010895A JP3541980B2 (en) | 1995-03-28 | 1995-03-28 | Calibration method for robot with visual sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH08272451A true JPH08272451A (en) | 1996-10-18 |
| JP3541980B2 JP3541980B2 (en) | 2004-07-14 |
Family
ID=13422025
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP07010895A Expired - Lifetime JP3541980B2 (en) | 1995-03-28 | 1995-03-28 | Calibration method for robot with visual sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3541980B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010108085A (en) * | 2008-10-28 | 2010-05-13 | Makino Milling Mach Co Ltd | Error correction method |
| JP2013215866A (en) * | 2012-04-12 | 2013-10-24 | Seiko Epson Corp | Robot system, robot system calibration method, calibration device, and digital camera |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5371927B2 (en) * | 2010-10-27 | 2013-12-18 | 三菱電機株式会社 | Coordinate system calibration method and robot system |
-
1995
- 1995-03-28 JP JP07010895A patent/JP3541980B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010108085A (en) * | 2008-10-28 | 2010-05-13 | Makino Milling Mach Co Ltd | Error correction method |
| JP2013215866A (en) * | 2012-04-12 | 2013-10-24 | Seiko Epson Corp | Robot system, robot system calibration method, calibration device, and digital camera |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3541980B2 (en) | 2004-07-14 |
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