JP2548721Y2 - Work positioning device with automatic calibration function - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to a work positioning device with an automatic calibration function.

[Conventional technology]

Conventionally, in a work positioning device using an image processing device, camera position data in a robot coordinate system is registered and stored in the image processing device. Therefore, when changing the camera position, it is necessary to manually reset the calibration of the image processing apparatus.

[Problems to be solved by the invention]

The above-described conventional work positioning apparatus has a drawback that the calibration work is performed manually and the required time is long. Further, since it is difficult to manually identify the rotation center position and an error is likely to occur, there is a disadvantage that the correction amount calculation accuracy of the XYθ table is low.

[Means for solving the problem]

The work positioning device with an automatic calibration function of the present invention is an XYθ table, an image processing device mounted on the XYθ table, which captures a position measurement mark of a target work, calculates and outputs the position data by image processing, and the position data. In a work positioning apparatus including a calculation unit that calculates each axis correction amount of the XYθ table based on the table and a table control unit that drives the XYθ table in accordance with each axis correction amount, a mounting position of the XYθ table by a pin or a guide. A jig plate having a reproduction mark whose value is sufficiently smaller than the required positioning precision and which has a reference mark which can be measured by the image processing device in a field of view at a reference setting position of the imaging camera; and a reference plate in the field of view of the imaging camera. First coordinate data (X1, Y1) indicating a measurement value of the mark position (P) by image processing; After the XYθ table is rotated by an arbitrary angle (Δθ), the position of the reference mark in the field of view of the imaging camera is based on second coordinate data (X2, Y2) indicating a measurement value by image processing. And a camera position calculation unit for calculating the camera position and outputting the calculated camera position to the calculation unit.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

 FIG. 1 is a block diagram of an embodiment of the present invention.

The XYθ table 1 mounts a jig plate 2 using a work and a pin or a guide. The imaging camera 3 images the work and the mark provided on the jig plate 2 and outputs image information a.

The control system of the present apparatus includes an image processing device 4, a calculation unit 5, a camera position calculation unit 6, and a table control unit 7. The image processing device 4 processes the image information a output from the imaging camera 3 and calculates and outputs mark position data b. The calculation unit 5 calculates and outputs each axis correction amount c to the XYθ table control unit 7 based on the mark position data b.
The table controller 7 converts each axis correction amount c into position command data d for the XYθ table 1 and drives the XYθ table 1 to correct the work position. The mark position data b and each axis correction amount c are input / output to the camera position calculation unit 6 via the calculation unit 5.

FIG. 2 is an explanatory diagram of symbols used in the automatic calibration calculation performed by the camera position calculation unit 6.

The automatic calibration is performed according to the following procedure.
First, the reference mark P on the jig plate in the initial state
Is measured to obtain position data (X ₁ , Y ₁ ).

Next, the table controller is instructed to rotate by Δθ, and re-position measurement is performed with the reference mark P moved to the position Q to obtain position data (X ₂ , Y ₂ ).

The camera position calculation unit 6 calculates the initial position coordinates (X ₁ , Y ₁ ) of the point P with respect to the rotation center O by the following equation.

_{X 1 = Rcosθ ... (1)} Y 1 = Rsinθ ... (2) where Further, the eccentricity (X _E , Y _E ) between the rotation center O and the table origin O is calculated by the following equation using the coordinate data (X _P , Y _P ) of the already registered point P with respect to the table origin.

In the position measurement of each work, a work position is calculated by using the camera position (X ₁ , Y ₁ ) obtained by the above calculation, and each axis is calculated by using the work position and the rotation center position (X _E , Y _E ). Calculate the correction amount.

[Effect of the invention]

As described above, the present invention has the effect of shortening the setup change operation time when the camera position is changed by automating the calibration that has been conventionally performed by the operator. In particular, since the position of the rotation center is also obtained by calculation, there is an effect that the calculation accuracy is improved as compared with the manual setting.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
FIG. 4 is an explanatory diagram of symbols used in an automatic calibration calculation unit performed by a camera position calculation unit illustrated in FIG. 1 XYθ table, 2… jig plate, 3… imaging camera, 4… image processing device body, 5… arithmetic unit, 6…
... Camera position calculation unit, 7... Table control unit, a... Image information, b... Mark position data, c.
d: Position command data.

Claims (1)

(57) [Scope of request for utility model registration] 1. An XYθ table, an image processing apparatus mounted on the XYθ table, imaging a position measurement mark of a target work, and calculating and outputting the position data by image processing, and each axis of the XYθ table based on the position data. In a work positioning apparatus including a calculation unit that calculates a correction amount and a table control unit that drives the XYθ table in accordance with each of the axis correction amounts, the mounting position reproduction accuracy of the XYθ table by a pin or a guide is more than the required positioning accuracy. An image of a jig plate having a reference mark having a small value and capable of position measurement by the image processing apparatus in a field of view at a reference setting position of the imaging camera, and an image of a position (P) of the reference mark in the field of view of the imaging camera The first coordinate data (X1, Y1) indicating the measured value by the processing and the XYθ table are rotated by an arbitrary angle (Δθ). A camera position calculation for calculating a camera position based on second coordinate data (X2, Y2) indicating a measurement value by image processing of a position of the reference mark in a field of view of the imaging camera and outputting the calculated position to a calculation unit A work positioning device with an automatic calibration function.