CN112862903A - Offset calibration method for chip mounter camera and suction rod - Google Patents
Offset calibration method for chip mounter camera and suction rod Download PDFInfo
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Abstract
The invention discloses a calibration method for offset between a chip mounter camera and a suction rod, which comprises the steps of arranging an external camera; recording the first mechanical coordinate; calculating the transformation relation between the second mechanical coordinate and the first image coordinate and the transformation relation between the third mechanical coordinate and the second image coordinate; setting a calibration plate; calculating to obtain a first reference mechanical coordinate and a second reference mechanical coordinate; calculating the offset of the original camera, the external camera and the suction rod according to the transformation relation between the original camera and the external camera at any mechanical coordinate and the coordinates of the first calibration plate and the second calibration plate which are aligned to the calibration plate; calculating the offset of the external camera, the original camera and the suction rod on the whole surface mounting platform; and calculating to obtain the offset of the original camera, the external camera and all the suction rods of the chip mounter on the whole mounting platform. Compared with the prior art, the influence of the guide rail precision on the mounting precision is reduced, and the mounting precision and the stability of the chip mounter are effectively improved.
Description
Technical Field
The invention relates to a chip mounter, in particular to a calibration method for offset between a chip mounter camera and a suction rod.
Background
When the multi-suction-rod chip mounter carries out high-precision mounting production, in order to ensure sufficiently high mounting precision, each mounting position needs to be photographed one by one and then mounted. The accuracy of the offset between the photographing camera and each suction rod is an important factor influencing the mounting accuracy.
At present, the commonly used calibration method of the offset of the camera and the suction rod assumes that the offset is a constant value and is independent of the mounting position. In the calibration process, the calibration seal is firstly installed at the head of the suction rod, the suction rod is moved to seal the calibration seal on the working plane, then the camera is moved to photograph the seal position, and the offset between the camera and the suction rod can be calculated. However, in the actual chip mounter equipment, due to certain errors in the machining precision and the mounting precision of the guide rail parts, the assumption that the offset between the camera and the suction rod is a constant value cannot be strictly met. This results in actual patch accuracy being lower than design requirements and failure to achieve stable processing accuracy during mass production of the device.
Disclosure of Invention
The invention aims to provide a calibration method for offset of a camera and a suction rod of a chip mounter, which aims to solve the technical problems that offset change values of the camera and the suction rod at different mounting positions can be accurately obtained, the problem that the offset of the camera and the suction rod is influenced by the precision of a guide rail is solved, and the precision and the stability of mounting production of the chip mounter are effectively improved.
In order to solve the problems, the invention adopts the following technical scheme: a calibration method for offset between a chip mounter camera and a suction rod comprises the following steps:
step S1, arranging an external camera moving together with the suction rod on the suction rod rack of the chip mounter;
step S2, mounting a calibration stamp on the head of one suction rod to be calibrated, driving the suction rod to move to the center of the mounting platform and move downwards, covering a calibration mark at the center of the mounting platform, and recording a first mechanical coordinate (Xmnr, Ymnr) when the suction rod covers the calibration mark;
step S3, moving the external camera and the original camera on a 3 x 3 array position point respectively, photographing the calibration mark in the step S2, recording second mechanical coordinates (Xmb, Ymb) of the original camera, first image coordinates (Xib, Yib) corresponding to the second mechanical coordinates (Xmb, Ymb) of the original camera, third mechanical coordinates (Xma, Yma) of the external camera and second image coordinates (Xia, Yia) corresponding to the third mechanical coordinates respectively, and calculating a transformation relation between the second mechanical coordinates of the original camera and the first image coordinates and a transformation relation between the third mechanical coordinates of the external camera and the second image coordinates;
step S4, arranging a calibration plate on the mounting platform;
step S5, respectively photographing all the dots on the calibration plate through the original camera and the external camera, and recording the sixth mechanical coordinate (Xmact) of the original camera during each photographingij,Ymactij) And corresponding third image coordinates (Xiact)ij,Yiactij) And a seventh mechanical coordinate (Xmbct) of the add-on cameraij,Ymbctij) And corresponding fourth image coordinates (Xidct)ij,Yibctij) Wherein subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate; and calculating a first reference mechanical coordinate (Xmac) when the original camera is aligned with the dot by the following formula (3)ij,Ymacij) Second reference mechanical coordinates (Xmbc) when aligning with the dots of the add-on cameraij,Ymbcij)；
Step S6,Obtaining a first reference mechanical coordinate (Xmac)ij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) Then, the first reference mechanical coordinate (Xmac) is usedij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) Calculating eighth mechanical coordinates (Xmac, Ymac) and ninth mechanical coordinates (Xmbc, Ymbc) when the original camera and the add-on camera are aligned with any calibration plate coordinates (Xc, Yc) except for the dots in the calibration plate as a reference, wherein subscript i in the first and second reference mechanical coordinates represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate; when the original camera and the external camera are positioned at any mechanical coordinate (Xm, Ym) except the first reference mechanical coordinate and the second reference mechanical coordinate, the coordinate (Xcam, Ycam) of a first calibration plate aligned with the original camera and the coordinate (Xcbm, Ycbm) of a second calibration plate aligned with the external camera are calculated to obtain the transformation relation between the any mechanical coordinate of the original camera and the coordinate of the first calibration plate aligned with the calibration plate, and the external camera is positioned at the transformation relation between the any mechanical coordinate and the coordinate of the second calibration plate aligned with the calibration plate;
step S7, calculating the offset of the original camera, the external camera and the suction rod according to the transformation relation between the original camera and the external camera in any mechanical coordinate and the first and second calibration plate coordinates of the alignment calibration plate;
step S8, calculating the offset of the external camera, the original camera and the suction rod on the whole mounting platform according to the offset of the original camera, the external camera and the suction rod obtained in the step S7 and the conversion relation calculated in the step S6;
and S9, repeating the step S2, the step S3 and the steps S5 to S8 to obtain the offset of the original camera and the plug-in camera of the chip mounter and all the suction rods on the whole mounting platform through calculation.
Further, step S3 includes:
step S31, the original camera and the external camera move to each array position point respectively, take pictures and record of the calibration marks, traverse 9 array position points, obtain a second mechanical coordinate of the original camera and a corresponding first image coordinate, a third mechanical coordinate of the external camera and a corresponding second image coordinate, and the transformation relation of the two is expressed by the following formula (1);
substituting the second mechanical coordinates (Xma, Yma), the first image coordinates (Xia, Yia), the third mechanical coordinates (Xmb, Ymb), and the second image coordinates (Xib, Yib) into equation (1) can calculate values of parameters m00, m01, m02, m10, m11, m12, m20, m21, m22, m30, m31, and m32 to obtain transformation parameters in a transformation relation;
step S32, substituting the image center coordinates (Xiar, Yiar) of the original camera and the image center coordinates (Xibr, Yibr) of the external camera into the following formula (2), calculating to obtain the fourth mechanical coordinates (Xmar, Ymar) of the original camera when aligning the calibration mark and the fifth mechanical coordinates (Xmbr, Ymbr) of the external camera when aligning the calibration mark,
further, the eighth mechanical coordinates (Xmac, Ymac) and the ninth mechanical coordinates (Xmbc, Ymbc) when the original camera and the add-on camera are aligned with the coordinates (Xc, Yc) of any calibration plate other than the dots in the calibration plate in step S6 are specifically: obtaining the calibration plate coordinates (Xc) of four dots near the arbitrary calibration plate coordinates (Xc, Yc)ij,Ycij)、(Xcij+1,Ycij+1)、(Xci+1j,Yci+1j)、(Xci+1j+1,Yci+1j+1) (ii) a The original camera is aligned to the calibration plate coordinates (Xc) of the first dotij,Ycij) The first reference machine coordinate of time is (Xmac)ij,Ymacij) Alignment of calibration plate coordinates (Xc) of the second dotij+1,Ycij+1) The first reference machine coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of calibration plate coordinates (Xc) of third doti+1j,Yci+1j) The first reference machine coordinate of time is (Xmac)i+1j,Ymaci+1j) Aligning the calibration plate with the fourth dotLabel (Xc)i+1j+1,Yci+1j+1) The first reference machine coordinate of time is (Xmac)i+1j+1,Ymaci+1j+1) Calculating and obtaining eighth mechanical coordinates (Xmac, Ymac) of the original camera when the coordinates (Xc, Yc) of any calibration plate except the circular points in the calibration plate are aligned through the following formula (4);
wherein, subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate;
obtaining calibration plate coordinates (Xc) of the external camera aiming at the first round pointij,Ycij) The second reference mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of calibration plate coordinates (Xc) of the second dotij+1,Ycij+1) The second reference mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1) Alignment of calibration plate coordinates (Xc) of third doti+1j,Yci+1j) The second reference mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth doti+1j+1,Yci+1j+1) The second reference mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Calculating a ninth mechanical coordinate (Xmbc, Ymbc) of the external camera when aiming at any calibration plate coordinate (Xc, Yc) except the dot in the calibration plate through the following formula (5);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Further, when the original camera and the add-on camera are calculated to be located at any mechanical coordinate (Xm, Ym) other than the first and second reference mechanical coordinates in step S6, the first calibration plate coordinate (Xcam, Ycam) aligned by the original camera and the second calibration plate coordinate (Xcbm, Ycbm) aligned by the add-on camera are specifically:
when the original camera is positioned at any mechanical coordinate (Xm, Ym), a first reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the aligned calibration plate is obtained, and the original camera is aligned with the calibration plate coordinate (Xc) of the first dot of the ith row and the jth columnij,Ycij) The first mechanical coordinate of time is (Xmac)ij,Ymacij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The first mechanical coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The first mechanical coordinate of time is (Xmac)i+1j,Ymaci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The first mechanical coordinate is (Xmac)i+1j+1,Ymaci+1j+1) When the original camera is located at any mechanical coordinate (Xm, Ym) except the first reference mechanical coordinate point, the first calibration plate coordinate (Xcam, Ym) of the calibration plate aimed at by the original camera is obtained through calculation according to the following formula (6);
wherein, subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate;
acquiring a second reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the calibration plate aligned with the external camera when the external camera is positioned at the any mechanical coordinate (Xm, Ym), and aligning the external camera to the calibration plate coordinate (Xc) of the first dot of the ith row and the jth columnij,Ycij) The second mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The second mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1)，Align the calibration plate coordinates (Xc) of the third dot of row (i + 1) and column (j)i+1j,Yci+1j) The second mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The second mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Second calibration plate coordinates (Xcbm, Ycbm) of a calibration plate at which the external camera is aligned when the external camera is at any mechanical coordinates (Xm, Ym) other than the second reference mechanical coordinates are calculated by the following formula (7);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Further, step S7 specifically includes:
step S71, according to the first mechanical coordinate (Xmnr, Ymnr) when the calibration mark is marked under the sucker cover in step S2, the calibration plate coordinate of four dots near the calibration plate coordinate of the calibration plate respectively aligned by the original camera and the external camera when the calibration plate coordinate is in the first mechanical coordinate, and the first reference mechanical coordinate (Xmac) corresponding to the dotsij,Ymacij)、(Xmacij+1,Ymacij+1)、(Xmaci+1j,Ymaci+1j)、(Xmaci+1j+1,Ymaci+1j+1) Second reference mechanical coordinate (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) Wherein, subscript i represents the row number of the dots near the calibration plate coordinate of the calibration plate aligned by the original camera, subscript j represents the column number of the dots near the calibration plate coordinate of the calibration plate aligned by the original camera, subscript p represents the row number of the dots near the calibration plate coordinate of the external camera aligned to the calibration plate, subscript q represents the column number of the dots near the calibration plate coordinate of the external camera aligned to the calibration plate, and the calibration plate coordinate (Xcar, Ycar) aligned by the original camera when the calibration mark is covered is calculated by the following formula (8)) -calibration plate coordinates (Xcbr, Ycbr) to which the add-on camera is aimed;
step S72, according to the fourth mechanical coordinate (Xmar, Ymar) when the original camera aligns the calibration mark and the first reference mechanical coordinate (Xmac) corresponding to the four dots near the calibration mark in the calibration boarduv,Ymacuv)、(Xmacuv+1,Ymacuv+1)、(Xmacu+1v,Ymacu+1v)、(Xmacu+1v+1,Ymacu+1v+1) Calculating calibration plate coordinates (Xcnr, Ycnr) of the calibration marks in the calibration plate by the following formula (9), wherein a subscript u denotes a row number of a dot near the calibration mark in the calibration plate, and a subscript v denotes a column number of a dot near the calibration mark in the calibration plate;
step S73, calculating the offset of the original camera, the external camera and the suction rod according to the following formula (10), wherein the calculated calibration mark time is the coordinate (Xcar, Ycar) of the calibration plate aligned by the original camera, the coordinate (Xcbr, Ycbr) of the calibration plate aligned by the external camera and the coordinate (Xcnr, Ycnr) of the calibration plate aligned by the calibration mark;
further, step S8 includes:
step S81, original cameraThe mechanical coordinate when aligning to the dots of the ith row and the jth column is (Xmac)ij,Ymacij) The calibration plate coordinate of the dot is (Xc)ij,Ycij) The second reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the external camera alignment calibration plate is (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) The coordinates of the dot calibration plate are (Xc)pq,Ycpq)、(Xcpq+1,Ycpq+1)、(Xcp+1q,Ycp+1q)、(Xcp+1q+1,Ycp+1q+1) Wherein, subscript i represents the row number of the dots of the calibration plate, and subscript j represents the column number of the dots of the calibration plate; subscript p represents the row number of dots near the calibration plate coordinates of the external camera alignment calibration plate, and subscript q represents the column number of dots near the calibration plate coordinates of the external camera alignment calibration plate; substituting the first reference mechanical coordinate, the second reference mechanical coordinate and the corresponding calibration plate coordinate which are obtained by calculation in the step S5 into the following formula (11) to calculate to obtain the calibration plate coordinate (Xcba) of the external camera aligning calibration plateij,Ycbaij) Calibration plate coordinates (Xcna) for aligning the calibration plate with the suction rodij,Ycnbij)；
Step S82, aligning the calibration board coordinate (Xcna) of the calibration board with the suction rodij,Ycnbij) As the suction rod reference coordinates, four suction rod reference coordinates near the arbitrary calibration plate coordinates are acquired, which are (Xcna)ij,Ycnaij)，(Xcnaij+1,Ycnaij+1)，(Xcnai+1j,Ycnai+1j)，(Xcnai+1j+1,Ycnai+1j+1) The corresponding machine coordinate is (Xmac)ij,Ymacij)，(Xmacij+1,Ymacij+1)，(Xmaci+1j,Ymaci+1j)，(Xmaci+1j+1,Ymaci+1j+1) The suction rod is aligned with any one of the calibration plates except the reference coordinates of the suction rodThe mechanical coordinates (Xmnc, Ymnc) at the time of designating the coordinates of the board are calculated by the following formula (12):
further, in step S4, the effective area of the calibration board covers the working range of the mounting platform, the diameter of the dots in the calibration board is 5mm, and the interval between the centers of two adjacent dots is 10 mm.
Further, in step S31, the original camera and the external camera move along the 'already' shaped path
Compared with the prior art, the external camera and the original camera of the chip mounter are arranged to take pictures of the calibration marks and take pictures of the dots on the calibration plate, and the relation between the offset and the mounting position of the original camera, the external camera and the suction rod on the whole mounting platform is calculated through the coordinate conversion relation among the mechanical coordinate, the image coordinate and the calibration plate coordinate, so that the influence of the guide rail precision on the mounting precision is reduced under the condition of not increasing the hardware cost, and the mounting precision and the stability of the chip mounter are effectively improved.
Drawings
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a schematic diagram of a calibration stamp according to the present invention.
Fig. 3 is a schematic view of a calibration plate of the present invention.
Fig. 4 is a schematic diagram of the position of a dual camera of the present invention.
Fig. 5 is a detailed flowchart of step S7 according to the present invention.
Fig. 6 is a detailed flowchart of step S8 according to the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples.
As shown in fig. 1, the invention discloses a calibration method for offset between a chip mounter camera and a suction rod, comprising the following steps:
step S1, arranging an external camera moving together with the suction rod on the suction rod frame of the chip mounter, wherein the lens of the external camera faces to the mounting platform of the chip mounter and shoots together with the original camera on the suction rod frame; as shown in fig. 4, the external cameras are symmetrically arranged at two opposite ends of the sucker rod frame;
step S2, installing a calibration stamp (figure 1) on the head of one suction rod to be calibrated, driving the suction rod to move to the center of the mounting platform and move downwards, covering a calibration mark at the center of the mounting platform, and recording a first mechanical coordinate (Xmnr, Ymnr) of the suction rod when the calibration mark is covered;
step S3, moving the external camera and the original camera on a 3 x 3 array position point respectively, photographing the calibration mark in the step S2, recording second mechanical coordinates (Xmb, Ymb) of the original camera, first image coordinates (Xib, Yib) corresponding to the second mechanical coordinates (Xmb, Ymb) of the original camera, third mechanical coordinates (Xma, Yma) of the external camera and second image coordinates (Xia, Yia) corresponding to the third mechanical coordinates respectively, and calculating to obtain a transformation relation between the second mechanical coordinates of the original camera and the first image coordinates and a transformation relation between the third mechanical coordinates of the external camera and the second image coordinates;
specifically, the method comprises the following steps:
step S31, the original camera and the external camera move to each array position point respectively, take pictures and record the calibration marks, move along a 'Chinese' character-shaped path, so that 9 array position points are traversed, a second mechanical coordinate of the original camera and a corresponding first image coordinate, a third mechanical coordinate of the external camera and a corresponding second image coordinate are obtained, and the transformation relation of the first mechanical coordinate and the second mechanical coordinate is expressed by the following formula (1);
the values of the parameters m00, m01, m02, m10, m11, m12, m20, m21, m22, m30, m31, m32 can be calculated by substituting the second machine coordinates (Xma, Yma), the first image coordinates (Xia, Yia), the third machine coordinates (Xmb, Ymb), and the second image coordinates (Xib, Yib) into equation (1), so as to obtain the transformation parameters in the transformation relationship.
Step S32, the image center coordinates (Xiar, Yiar) of the original camera and the image center coordinates (Xibr, Yibr) of the external camera are substituted into the following formula (2), so that the fourth mechanical coordinates (Xmar, Ymar) of the original camera when the external camera is aligned with the calibration mark and the fifth mechanical coordinates (Xmbr, Ymbr) of the external camera when the external camera is aligned with the calibration mark can be calculated,
Xmar＝m00×Xiar+m01×Yiar+m02；
the image center coordinates are obtained by dividing the length and width of the external camera and the original camera by 2.
In the present invention, the spacing between the array position points may be equal or unequal.
Step S4, arranging a calibration plate on the mounting platform, enabling each edge of the calibration plate to be parallel to an X axis and a Y axis of the mounting platform respectively, enabling the effective area of the calibration plate to cover the working range of the mounting platform, enabling the diameter of dots in the calibration plate to be 5mm, enabling the interval between the centers of two adjacent dots to be 10mm, and enabling the dot arrays to be distributed on the whole calibration plate; the distance between the dots is larger than the diameter of the dots, so that the two dots are not overlapped, and the number of reference points is too small when the distance is too large, which is not beneficial to improving the calibration precision. And establishing a coordinate system by using a calibration plate, and recording the coordinates of the calibration plate as (Xc, Yc).
Step S5, respectively photographing all the dots on the calibration plate through the original camera and the external camera, and recording the sixth mechanical coordinate (Xmact) of the original camera during each photographingij,Ymactij) And corresponding third image coordinates (Xiact)ij,Yiactij) And a seventh mechanical coordinate (Xmbct) of the add-on cameraij,Ymbctij) And corresponding fourth image coordinates (Xidct)ij,Yibctij) Where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Due to the time phase of taking a pictureWhen the machine has the condition of not completely aligning the dots, a first reference mechanical coordinate (Xmac) when the original camera aligns the dots is obtained by calculation according to the following formula (3)ij,Ymacij) Second reference mechanical coordinates (Xmbc) when aligning with the dots of the add-on cameraij,Ymbcij)；
Where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Step S6, obtaining the first reference mechanical coordinate (Xmac) of the original camera and the external camera alignment dot in step S5ij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) Then, the first reference mechanical coordinate (Xmac) corresponding to the dots is usedij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) Calculating eighth mechanical coordinates (Xmac, Ymac) and ninth mechanical coordinates (Xmbc, Ymbc) when the original camera and the add-on camera are aligned with any calibration plate coordinates (Xc, Yc) except for the dots in the calibration plate as a reference, wherein subscript i in the first and second reference mechanical coordinates represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate; the method comprises the steps of respectively aligning an original camera and an external camera to coordinates (Xc, Yc) of an arbitrary calibration plate except for dots in the calibration plate, and first reference mechanical coordinates and second reference mechanical coordinates corresponding to four dots near the coordinates of the arbitrary calibration plate, and calculating to obtain eighth mechanical coordinates (Xmac, Ymac) and ninth mechanical coordinates (Xmbc, Ymbc), specifically:
setting the coordinate (Xc, Yc) of the arbitrary calibration plate among the dots of the ith row, the ith +1 th row, the jth column and the jth +1 th column, then the calibration plate coordinates of four dots near the calibration plate coordinate are respectively expressed as (Xc) of the calibration plate coordinate of the dot of the ith row and the jth columnij,Ycij) The calibration plate coordinate of the ith row and the j +1 th column of dots is (Xc)ij+1,Ycij+1) The coordinate of the calibration plate of the (i + 1) th row and the (j) th column of dots is (Xc)i+1j,Yci+1j)，The coordinates of the calibration plate of the dots of the (i + 1) th row and the (j + 1) th column are (Xc)i+1j+1,Yci+1j+1). The original camera is aligned with the calibration plate coordinate (Xc) of the first dot of the ith row and jth columnij,Ycij) The first reference machine coordinate of time is (Xmac)ij,Ymacij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The first reference machine coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The first reference machine coordinate of time is (Xmac)i+1j,Ymaci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The first reference machine coordinate of time is (Xmac)i+1j+1,Ymaci+1j+1) (ii) a And (4) calculating an eighth mechanical coordinate (Xmac, Ymac) of the original camera when the coordinate (Xc, Yc) of any calibration plate except the circular point in the calibration plate is aligned with the original camera.
Where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Setting an external hanging camera to align with the coordinates (Xc) of the calibration plate of the first dots of the ith row and the jth columnij,Ycij) The second reference mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The second reference mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The second reference mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The second reference mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Calculating to obtain the mean square of the alignment calibration plate of the external camera according to the following formula (5)A ninth mechanical coordinate (Xmbc, Ymbc) at which the arbitrary calibration plate coordinate (Xc, Yc) other than the dot is located;
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Assuming that the arbitrary calibration plate coordinates (Xc, Yc) are between the dots on the 1 st, 2 nd, 1 st and 2 nd rows, columns of the calibration plate, the calibration plate coordinates of the four dots near the calibration plate coordinates are expressed as (Xc) for the dots on the 1 st, 1 st and 1 st rows11,Yc11) The dots in row 1 and column 2 are (Xc)12,Yc12) The dots in row 2 and column 1 are (Xc)21,Yc21) The dots in row 2 and column 2 are (Xc)22,Yc22). The original camera is aligned with the dots (Xc) of the 1 st row and the 1 st column11,Yc11) The first reference machine coordinate of time is (Xmac)11,Ymac11) Aligned with the dots of row 1 and column 2 (Xc)12,Yc12) The first reference machine coordinate of time is (Xmac)12,Ymac12) Aligned with the dots (Xc) of row 2 and column 121,Yc21) The first reference machine coordinate of time is (Xmac)21,Ymac21) Aligned with the 2 nd row and column dots (Xc)22,Yc22) The first reference machine coordinate of time is (Xmac)22,Ymac22). Then the eighth mechanical coordinate (Xmac, Ymac) when the original camera is aligned with the calibration plate coordinate (Xc, Yc) other than the dots in the calibration plate can be calculated by substituting equation (4):
assume that the add-on camera is aimed at the row 1, column 1 dots (Xc)11,Yc11) Second of (1)The reference machine coordinate is (Xmbc)11,Ymbc11) Aligned with the dots of row 1 and column 2 (Xc)12,Yc12) The second reference mechanical coordinate of time is (Xmbc)12,Ymbc12) Aligned with the dots (Xc) of row 2 and column 121,Yc21) The second reference mechanical coordinate of time is (Xmbc)21,Ymbc21) Aligned with the 2 nd row and column dots (Xc)22,Yc22) The second reference mechanical coordinate of time is (Xmbc)22,Ymbc22). The ninth mechanical coordinate (Xmbc, Ymbc) at which the external camera is directed to the arbitrary calibration plate coordinate (Xc, Yc) in addition to the dots in the calibration plate can be calculated by the following formula:
step S6 further includes calculating the first reference machine coordinate (Xmac)ij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) When the original camera and the external camera are positioned at any mechanical coordinate (Xm, Ym) except the first and second reference mechanical coordinates, calculating a first calibration plate coordinate (Xcam, Ycam) aligned by the original camera and a second calibration plate coordinate (Xcbm, Ycbm) aligned by the external camera to obtain a transformation relation between the any mechanical coordinate of the original camera and the first calibration plate coordinate of the alignment calibration plate, and the external camera is positioned at the transformation relation between the any mechanical coordinate and the second calibration plate coordinate of the alignment calibration plate;
specifically, when the original camera is at the arbitrary mechanical coordinate (Xm, Ym), the first reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the aligned calibration plate is obtained, and when the original camera is at the arbitrary mechanical coordinate (Xm, Ym), the calibration plate coordinate (Xcam, Ycam) of the aligned calibration plate is between the ith row, the ith +1 th row, the jth column and the jth +1 th column, the calibration plate coordinates of the four dots are respectively represented as (Xc) in the ith row and the jth columnij,Ycij) The ith row and the j +1 th column have dots of (Xc)ij+1,Ycij+1) The dots in the (i + 1) th row and the (j) th column are (Xc)i+1j,Yci+1j) The dots in the (i + 1) th row and the (j + 1) th column are(Xci+1j+1,Yci+1j+1). The original camera is aligned with the calibration plate coordinate (Xc) of the first dot of the ith row and jth columnij,Ycij) The first mechanical coordinate of time is (Xmac)ij,Ymacij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The first mechanical coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The first mechanical coordinate of time is (Xmac)i+1j,Ymaci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The first mechanical coordinate is (Xmac)i+1j+1,Ymaci+1j+1) When the original camera is located at any mechanical coordinate (Xm, Ym) except the first reference mechanical coordinate point, the first calibration plate coordinate (Xcam, Ym) of the calibration plate aimed at by the original camera is obtained through calculation according to the following formula (6);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Acquiring a second reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the calibration plate aligned with the external camera when the external camera is positioned at the any mechanical coordinate (Xm, Ym), and setting the calibration plate coordinate (Xc) of the first dot aligned with the ith row and the jth column of the external cameraij,Ycij) The second mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The second mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The second mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The second mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Second calibration plate coordinates (Xcbm, Ycbm) of a calibration plate at which the external camera is aligned when the external camera is at any mechanical coordinates (Xm, Ym) other than the second reference mechanical coordinates are calculated by the following formula (7);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
Assuming that the original camera is at the arbitrary mechanical coordinates (Xm, Ym), the calibration plate coordinates (Xcam, Ycam) of the original camera alignment calibration plate are between the dots of the 3 rd row, the 4 th row, the 3 rd column and the 4 th column, the calibration plate coordinates of the four dots are respectively expressed as (Xc) for the dots of the 3 rd row and the 3 rd column in the 3 rd row33,Yc33) The dots in row 3 and column 4 are (Xc)34,Yc34) The dots in row 4 and column 3 are (Xc)43,Yc43) The dots in row 4 and column 4 are (Xc)44,Yc44). The original camera is aligned with the 3 rd row and 3 rd column dots (Xc)33,Yc33) The first mechanical coordinate of time is (Xmac)33,Ymac33) Aligned with the dots (Xc) in row 3 and column 434,Yc34) The first mechanical coordinate of time is (Xmac)34,Ymac34) Aligned with the 4 th row and 3 rd column dots (Xc)43,Yc43) The first mechanical coordinate of time is (Xmac)43,Ymac43) Align with the 4 th row and 4 th column dots (Xc)44,Yc44) The first mechanical coordinate of time is (Xmac)44,Ymac44). Then the first calibration plate coordinates (Xcam, Ycam) of the original camera aligned to the calibration plate when the original camera is at the arbitrary mechanical coordinates (Xm, Ym) can be calculated by the following formula;
similarly, assuming that the add-on camera is at any mechanical coordinate (Xm, Ym), the second calibration plate coordinate (Xcbm, Ycbm) of the add-on camera alignment calibration plate is in line 3,The calibration plate coordinates of four nearby dots among the dots in the 4 th row, the 8 th column and the 9 th column are respectively expressed as (Xc) for the dots in the 3 rd row and the 8 th column38,Yc38) The calibration plate coordinates of the dots of row 3 and column 9 are (Xc)39,Yc39) The calibration plate coordinates of the dots of row 4 and column 8 are (Xc)48,Yc48) The calibration plate coordinates of the dots of row 4 and column 9 are (Xc)49,Yc49). The coordinate of the calibration plate of the external camera aiming at the dots of the 3 rd row and the 8 th column is (Xc)38,Yc38) The second reference mechanical coordinate of time is (Xmbc)38,Ymbc38) Alignment of calibration plate coordinates (Xc) for row 3 and column 9 dots39,Yc39) Second reference mechanical coordinates (Xmbc)39,Ymbc39) Alignment of calibration plate coordinates (Xc) for the dots of row 4 and column 848,Yc48) The second reference mechanical coordinate of time is (Xmbc)48,Ymbc48) Alignment of calibration plate coordinates (Xc) for the dots of row 4 and column 949,Yc49) The second reference mechanical coordinate of time is (Xmbc)49,Ymbc49). Then the second calibration plate coordinates (Xcbm, Ycbm) of the external camera directed to the calibration plate when the external camera is at the mechanical coordinates (Xm, Ym) can be calculated by the following formula;
and respectively obtaining the transformation relation between the original camera at any mechanical coordinate and the first calibration plate coordinate of the alignment calibration plate through the calculation, and the transformation relation between the external camera at any mechanical coordinate and the second calibration plate coordinate of the alignment calibration plate.
S7, calculating the offset of the original camera, the plug-in camera and the suction rod according to the transformation relation between the original camera and the plug-in camera in any mechanical coordinate and the first and second calibration plate coordinates of the alignment calibration plate obtained in the step S6;
in particular, as shown in figure 5,
step S71, according to the first mechanical coordinate (Xmnr) when the index is marked under the sucker cover in step S2Ymnr) and calibration plate coordinates of four dots near the calibration plate coordinates of the calibration plate respectively aligned by the original camera and the external camera when the original camera and the external camera are located at the first mechanical coordinates, and first reference mechanical coordinates (Xmac) corresponding to the dotsij,Ymacij)、(Xmacij+1,Ymacij+1)、(Xmaci+1j,Ymaci+1j)、(Xmaci+1j+1,Ymaci+1j+1) Second reference mechanical coordinate (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) The subscript i represents the row number of dots near the calibration plate coordinate of the calibration plate aligned by the original camera, the subscript j represents the column number of dots near the calibration plate coordinate of the calibration plate aligned by the original camera, the subscript p represents the row number of dots near the calibration plate coordinate of the external camera aligned by the calibration plate, the subscript q represents the column number of dots near the calibration plate coordinate of the external camera aligned by the calibration plate, and the calibration plate coordinate (Xcar, Ycar) aligned by the original camera and the calibration plate coordinate (Xcbr, Ycbr) aligned by the external camera when the subscript calibration mark is covered are obtained through calculation according to the following formula (8);
the subscript i represents the row number of dots near the calibration plate coordinate of the calibration plate aligned with the original camera, the subscript j represents the column number of dots near the calibration plate coordinate of the calibration plate aligned with the original camera, the subscript p represents the row number of dots near the calibration plate coordinate of the external camera aligned with the calibration plate, and the subscript q represents the column number of dots near the calibration plate coordinate of the external camera aligned with the calibration plate.
Assuming that the calibration plate coordinates of the original camera alignment calibration plate are among the dots in the 3 rd row, the 4 th row, the 3 rd column and the 4 th column, and the calibration plate coordinates of the external camera alignment calibration plate are among the dots in the 3 rd row, the 4 th row, the 8 th column and the 9 th column, the first mechanical coordinate (Xmnr, Ymnr) is substituted into the following formula:
step S72, according to the fourth mechanical coordinate (Xmar, Ymar) when the original camera aligns the calibration mark and the first reference mechanical coordinate (Xmac) corresponding to the four dots near the calibration mark in the calibration boarduv,Ymacuv)、(Xmacuv+1,Ymacuv+1)、(Xmacu+1v,Ymacu+1v)、(Xmacu+1v+1,Ymacu+1v+1) Calculating calibration plate coordinates (Xcnr, Ycnr) of the calibration marks in the calibration plate by the following formula (9), wherein a subscript u denotes a row number of a dot near the calibration mark in the calibration plate, and a subscript v denotes a column number of a dot near the calibration mark in the calibration plate;
where subscript u represents the row number of the nearby dots of the calibration mark in the calibration plate and subscript v represents the column number of the nearby dots of the calibration mark in the calibration plate.
Assuming that the calibration mark is located between the dots in the calibration board in the 3 rd row, the 4 th row, the 5 th column and the 6 th column, the first reference mechanical coordinates corresponding to the four dots are respectively expressed as (Xmac)35,Ymac35)、(Xmac36,Ymac36)、(Xmac45,Ymac45)、(Xmac46,Ymac46) The calculation is performed according to the above equation (9):
step S73, calculating the offset of the original camera, the external camera and the suction rod according to the following formula (10), wherein the calculated calibration mark time is the coordinate (Xcar, Ycar) of the calibration plate aligned by the original camera, the coordinate (Xcbr, Ycbr) of the calibration plate aligned by the external camera and the coordinate (Xcnr, Ycnr) of the calibration plate aligned by the calibration mark;
the coordinates (Xcar, Ycar) of a calibration board aligned with the original camera, the coordinates (Xcbr, Ycbr) of a calibration board aligned with the add-on camera and the coordinates (Xcnr, Ycnr) of the calibration board marked in the calibration board are substituted into a formula (10) to calculate parameters Dn and An, Dn is a distance, and An is An angle.
Step S8, calculating the offset of the external camera, the original camera and the suction rod on the whole mounting platform according to the offset of the original camera, the external camera and the suction rod obtained in the step S7 and the conversion relation calculated in the step S6; comprising (as shown in figure 6):
step S81, let the original camera align with the ith row and jth column of dots with the mechanical coordinate (Xmac)ij,Ymacij) The calibration plate coordinate of the dot is (Xc)ij,Ycij) At this time, the coordinate of the calibration board aligned by the external camera is between the p-th, p + 1-th row, the q-th and q + 1-th columns of dots, and the second reference mechanical coordinate corresponding to four dots near the coordinate of the calibration board aligned by the external camera is (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) The coordinates of the dot calibration plate are (Xc)pq,Ycpq)、(Xcpq+1,Ycpq+1)、(Xcp+1q,Ycp+1q)、(Xcp+1q+1,Ycp+1q+1) Wherein, subscript i represents the row number of the dots of the calibration plate, and subscript j represents the column number of the dots of the calibration plate; subscript p represents the row number of dots near the calibration plate coordinates of the external camera alignment calibration plate, and subscript q represents the column number of dots near the calibration plate coordinates of the external camera alignment calibration plate; calculated in step S5The first reference mechanical coordinate, the second reference mechanical coordinate and the corresponding calibration plate coordinate are substituted into the following formula (11) for calculation to obtain the calibration plate coordinate (Xcba) of the external camera aligned to the calibration plate at the momentij,Ycbaij) Calibration plate coordinates (Xcna) for aligning the calibration plate with the suction rodij,Ycnbij)；
Wherein, subscript i represents the row number of the dots of the calibration plate, and subscript j represents the column number of the dots of the calibration plate; subscript p denotes a row number of dots near the calibration plate coordinates of the exterior camera alignment calibration plate, and subscript q denotes a column number of dots near the calibration plate coordinates of the exterior camera alignment calibration plate.
Step S82, align and divide the calibration plate coordinate (Xcna) for the suction rodij,Ycnbij) Any calibration plate coordinate (Xc, Yc) of the other calibration plates, and calibration plate coordinate (Xcna) of the calibration plate aligned with the suction rodij,Ycnbij) As the suction bar reference coordinates, four suction bar reference coordinates near the arbitrary calibration plate coordinates are set between the i-th row, the i + 1-th row, the j-th column and the j + 1-th column, and the four suction bar reference coordinates are respectively expressed as (Xcna)ij,Ycnaij)，(Xcnaij+1,Ycnaij+1)，(Xcnai+1j,Ycnai+1j)，(Xcnai+1j+1,Ycnai+1j+1) The corresponding machine coordinate is (Xmac)ij,Ymacij)，(Xmacij+1,Ymacij+1)，(Xmaci+1j,Ymaci+1j)，(Xmaci+1j+1,Ymaci+1j+1) Then, the mechanical coordinates (Xmnc, Ymnc) at which the suction stick is aligned with the coordinates of any calibration plate other than the suction stick reference coordinates in the calibration plate are calculated by the following equation (12):
and S9, repeating the step S2, the step S3 and the steps S5 to S8 to obtain the offset of the original camera and the plug-in camera of the chip mounter and all the suction rods on the whole mounting platform through calculation.
After the offset of the suction rod and the original camera on the whole mounting platform is obtained, when mounting is carried out, the workpiece is photographed through the original camera, and the current suction rod is moved to the position of the workpiece to be mounted according to the offset of the current suction rod and the original camera.
When mounting, the original camera shoots the position of the workpiece to obtain the mechanical coordinates (Xmaw, Ymaw) of the workpiece when the original camera is aligned with the workpiece, the calibration plate coordinates (Xcwm, Ycwm) of the workpiece under the calibration plate coordinate system are calculated according to the formula (6) (Xm, Ym in the formula (6) is replaced), and the mechanical coordinates (Xmnw, Ymnw) (namely Xmnc, Ymnc) of the sucker when mounting is obtained from the calibration plate coordinates (Xcwm, Ycwm) of the sucker under the calibration plate coordinate system according to the formula (12) in the step S8 (XC, YC in the formula (12) is replaced).
Compared with the prior art, the invention reduces the influence of the guide rail precision on the mounting precision and effectively improves the mounting precision and stability of the chip mounter under the condition of not increasing the hardware cost by adopting the technology of calibrating the offset between the camera and the suction rod by the double cameras. The processing precision is improved, the general method assumes that the position relation between the camera and the suction rod is a fixed value, which is not consistent with the working condition of an actual machine, the method of the invention refines the calculation method of the position relation between the camera and the suction rod, and uses different camera suction rod position relations to calculate at different mounting positions, thus avoiding the influence of the precision error and the installation error of mechanical devices on the mounting precision.
Claims (8)
1. A calibration method for offset between a chip mounter camera and a suction rod is characterized by comprising the following steps: the method comprises the following steps:
step S1, arranging an external camera moving together with the suction rod on the suction rod rack of the chip mounter;
step S2, mounting a calibration stamp on the head of one suction rod to be calibrated, driving the suction rod to move to the center of the mounting platform and move downwards, covering a calibration mark at the center of the mounting platform, and recording a first mechanical coordinate (Xmnr, Ymnr) when the suction rod covers the calibration mark;
step S3, moving the external camera and the original camera on a 3 x 3 array position point respectively, photographing the calibration mark in the step S2, recording second mechanical coordinates (Xmb, Ymb) of the original camera, first image coordinates (Xib, Yib) corresponding to the second mechanical coordinates (Xmb, Ymb) of the original camera, third mechanical coordinates (Xma, Yma) of the external camera and second image coordinates (Xia, Yia) corresponding to the third mechanical coordinates respectively, and calculating a transformation relation between the second mechanical coordinates of the original camera and the first image coordinates and a transformation relation between the third mechanical coordinates of the external camera and the second image coordinates;
step S4, arranging a calibration plate on the mounting platform;
step S5, respectively photographing all the dots on the calibration plate through the original camera and the external camera, and recording the sixth mechanical coordinate (Xmact) of the original camera during each photographingij,Ymactij) And corresponding third image coordinates (Xiact)ij,Yiactij) And a seventh mechanical coordinate (Xmbct) of the add-on cameraij,Ymbctij) And corresponding fourth image coordinates (Xidct)ij,Yibctij) Wherein subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate; and calculating a first reference mechanical coordinate (Xmac) when the original camera is aligned with the dot by the following formula (3)ij,Ymacij) Second reference mechanical coordinates (Xmbc) when aligning with the dots of the add-on cameraij,Ymbcij)；
In step S6, the first reference machine coordinate (Xmac) is obtainedij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) Then, the first reference mechanical coordinate (Xmac) is usedij,Ymacij) And a second reference mechanical coordinate (Xmbc)ij,Ymbcij) MakingCalculating eighth mechanical coordinates (Xmac, Ymac) and ninth mechanical coordinates (Xmbc, Ymbc) when the original camera and the add-on camera are aligned with any calibration plate coordinates (Xc, Yc) except for the dots in the calibration plate for reference, wherein subscript i in the first and second reference mechanical coordinates represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate; when the original camera and the external camera are positioned at any mechanical coordinate (Xm, Ym) except the first reference mechanical coordinate and the second reference mechanical coordinate, the coordinate (Xcam, Ycam) of a first calibration plate aligned with the original camera and the coordinate (Xcbm, Ycbm) of a second calibration plate aligned with the external camera are calculated to obtain the transformation relation between the any mechanical coordinate of the original camera and the coordinate of the first calibration plate aligned with the calibration plate, and the external camera is positioned at the transformation relation between the any mechanical coordinate and the coordinate of the second calibration plate aligned with the calibration plate;
step S7, calculating the offset of the original camera, the external camera and the suction rod according to the transformation relation between the original camera and the external camera in any mechanical coordinate and the first and second calibration plate coordinates of the alignment calibration plate;
step S8, calculating the offset of the external camera, the original camera and the suction rod on the whole mounting platform according to the offset of the original camera, the external camera and the suction rod obtained in the step S7 and the conversion relation calculated in the step S6;
and S9, repeating the step S2, the step S3 and the steps S5 to S8 to obtain the offset of the original camera and the plug-in camera of the chip mounter and all the suction rods on the whole mounting platform through calculation.
2. The method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: step S3 includes:
step S31, the original camera and the external camera move to each array position point respectively, take pictures and record of the calibration marks, traverse 9 array position points, obtain a second mechanical coordinate of the original camera and a corresponding first image coordinate, a third mechanical coordinate of the external camera and a corresponding second image coordinate, and the transformation relation of the two is expressed by the following formula (1);
substituting the second mechanical coordinates (Xma, Yma), the first image coordinates (Xia, Yia), the third mechanical coordinates (Xmb, Ymb), and the second image coordinates (Xib, Yib) into equation (1) can calculate values of parameters m00, m01, m02, m10, m11, m12, m20, m21, m22, m30, m31, and m32 to obtain transformation parameters in a transformation relation;
step S32, substituting the image center coordinates (Xiar, Yiar) of the original camera and the image center coordinates (Xibr, Yibr) of the external camera into the following formula (2), calculating to obtain the fourth mechanical coordinates (Xmar, Ymar) of the original camera when aligning the calibration mark and the fifth mechanical coordinates (Xmbr, Ymbr) of the external camera when aligning the calibration mark,
3. the method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: in step S6, the eighth mechanical coordinate (Xmac, Ymac) and the ninth mechanical coordinate (Xmbc, Ymbc) when the original camera and the add-on camera are aligned with any calibration plate coordinate (Xc, Yc) other than the circular dots in the calibration plate are specifically calculated as follows: obtaining the calibration plate coordinates (Xc) of four dots near the arbitrary calibration plate coordinates (Xc, Yc)ij,Ycij)、(Xcij+1,Ycij+1)、(Xci+1j,Yci+1j)、(Xci+1j+1,Yci+1j+1) (ii) a The original camera is aligned to the calibration plate coordinates (Xc) of the first dotij,Ycij) The first reference machine coordinate of time is (Xmac)ij,Ymacij) Alignment of calibration plate coordinates (Xc) of the second dotij+1,Ycij+1) The first reference machine coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of calibration plate coordinates (Xc) of third doti+1j,Yci+1j) The first reference machine coordinate of time is (Xmac)i+1j,Ymaci+1j) Aligned with the fourth dotCalibration plate coordinates (Xc)i+1j+1,Yci+1j+1) The first reference machine coordinate of time is (Xmac)i+1j+1,Ymaci+1j+1) Calculating and obtaining eighth mechanical coordinates (Xmac, Ymac) of the original camera when the coordinates (Xc, Yc) of any calibration plate except the circular points in the calibration plate are aligned through the following formula (4);
wherein, subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate;
obtaining calibration plate coordinates (Xc) of the external camera aiming at the first round pointij,Ycij) The second reference mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of calibration plate coordinates (Xc) of the second dotij+1,Ycij+1) The second reference mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1) Alignment of calibration plate coordinates (Xc) of third doti+1j,Yci+1j) The second reference mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth doti+1j+1,Yci+1j+1) The second reference mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Calculating a ninth mechanical coordinate (Xmbc, Ymbc) of the external camera when aiming at any calibration plate coordinate (Xc, Yc) except the dot in the calibration plate through the following formula (5);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
4. The method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: when the original camera and the add-on camera are in any mechanical coordinates (Xm, Ym) except the first and second reference mechanical coordinates in step S6, the first calibration plate coordinates (Xcam, Ycam) aligned by the original camera and the second calibration plate coordinates (Xcbm, Ycbm) aligned by the add-on camera are specifically:
when the original camera is positioned at any mechanical coordinate (Xm, Ym), a first reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the aligned calibration plate is obtained, and the original camera is aligned with the calibration plate coordinate (Xc) of the first dot of the ith row and the jth columnij,Ycij) The first mechanical coordinate of time is (Xmac)ij,Ymacij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The first mechanical coordinate of time is (Xmac)ij+1,Ymacij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The first mechanical coordinate of time is (Xmac)i+1j,Ymaci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The first mechanical coordinate is (Xmac)i+1j+1,Ymaci+1j+1) When the original camera is located at any mechanical coordinate (Xm, Ym) except the first reference mechanical coordinate point, the first calibration plate coordinate (Xcam, Ym) of the calibration plate aimed at by the original camera is obtained through calculation according to the following formula (6);
wherein, subscript i represents the row number of the dots in the calibration plate, and subscript j represents the column number of the dots in the calibration plate;
acquiring a second reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the calibration plate aligned with the external camera when the external camera is positioned at the any mechanical coordinate (Xm, Ym), and aligning the external camera to the calibration plate coordinate (Xc) of the first dot of the ith row and the jth columnij,Ycij) The second mechanical coordinate of time is (Xmbc)ij,Ymbcij) Alignment of the calibration coordinates (Xc) of the second dot in the ith row and the j +1 th columnij+1,Ycij+1) The second mechanical coordinate of time is (Xmbc)ij+1,Ymbcij+1) Alignment of the calibration plate coordinates (Xc) of the third dot in row (i + 1) and column (j)i+1j,Yci+1j) The second mechanical coordinate of time is (Xmbc)i+1j,Ymbci+1j) Alignment of calibration plate coordinates (Xc) of the fourth dot of row (i + 1) and column (j + 1)i+1j+1,Yci+1j+1) The second mechanical coordinate of time is (Xmbc)i+1j+1,Ymbci+1j+1) Second calibration plate coordinates (Xcbm, Ycbm) of a calibration plate at which the external camera is aligned when the external camera is at any mechanical coordinates (Xm, Ym) other than the second reference mechanical coordinates are calculated by the following formula (7);
where subscript i represents the row number of the dots in the calibration plate and subscript j represents the column number of the dots in the calibration plate.
5. The method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: step S7 specifically includes:
step S71, according to the first mechanical coordinate (Xmnr, Ymnr) when the calibration mark is marked under the sucker cover in step S2, the calibration plate coordinate of four dots near the calibration plate coordinate of the calibration plate respectively aligned by the original camera and the external camera when the calibration plate coordinate is in the first mechanical coordinate, and the first reference mechanical coordinate (Xmac) corresponding to the dotsij,Ymacij)、(Xmacij+1,Ymacij+1)、(Xmaci+1j,Ymaci+1j)、(Xmaci+1j+1,Ymaci+1j+1) Second reference mechanical coordinate (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) Wherein, the subscript i represents the row number of dots near the calibration plate coordinates of the calibration plate to which the original camera is directed, hereinafterThe mark j represents the column number of dots near the coordinate of the calibration plate aligned with the original camera, the mark p represents the row number of dots near the coordinate of the calibration plate aligned with the external camera, the mark q represents the column number of dots near the coordinate of the calibration plate aligned with the external camera, and the coordinate (Xcar, Ycar) of the calibration plate aligned with the original camera and the coordinate (Xcbr, Ycbr) of the calibration plate aligned with the external camera when the mark is covered are obtained through calculation according to the following formula (8);
step S72, according to the fourth mechanical coordinate (Xmar, Ymar) when the original camera aligns the calibration mark and the first reference mechanical coordinate (Xmac) corresponding to the four dots near the calibration mark in the calibration boarduv,Ymacuv)、(Xmacuv+1,Ymacuv+1)、(Xmacu+1v,Ymacu+1v)、(Xmacu+1v+1,Ymacu+1v+1) Calculating calibration plate coordinates (Xcnr, Ycnr) of the calibration marks in the calibration plate by the following formula (9), wherein a subscript u denotes a row number of a dot near the calibration mark in the calibration plate, and a subscript v denotes a column number of a dot near the calibration mark in the calibration plate;
step S73, calculating the offset of the original camera, the external camera and the suction rod according to the following formula (10), wherein the calculated calibration mark time is the coordinate (Xcar, Ycar) of the calibration plate aligned by the original camera, the coordinate (Xcbr, Ycbr) of the calibration plate aligned by the external camera and the coordinate (Xcnr, Ycnr) of the calibration plate aligned by the calibration mark;
6. the method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: step S8 includes:
step S81, the mechanical coordinate when the original camera is aligned with the dot on the ith row and the jth column is (Xmac)ij,Ymacij) The calibration plate coordinate of the dot is (Xc)ij,Ycij) The second reference mechanical coordinate corresponding to four dots near the calibration plate coordinate of the external camera alignment calibration plate is (Xmbc)pq,Ymbcpq)、(Xmbcpq+1,Ymbcpq+1)、(Xmbcp+1q,Ymbcp+1q)、(Xmbcp+1q+1,Ymbcp+1q+1) The coordinates of the dot calibration plate are (Xc)pq,Ycpq)、(Xcpq+1,Ycpq+1)、(Xcp+1q,Ycp+1q)、(Xcp+1q+1,Ycp+1q+1) Wherein, subscript i represents the row number of the dots of the calibration plate, and subscript j represents the column number of the dots of the calibration plate; subscript p represents the row number of dots near the calibration plate coordinates of the external camera alignment calibration plate, and subscript q represents the column number of dots near the calibration plate coordinates of the external camera alignment calibration plate; substituting the first reference mechanical coordinate, the second reference mechanical coordinate and the corresponding calibration plate coordinate which are obtained by calculation in the step S5 into the following formula (11) to calculate to obtain the calibration plate coordinate (Xcba) of the external camera aligning calibration plateij,Ycbaij) Calibration plate coordinates (Xcna) for aligning the calibration plate with the suction rodij,Ycnbij)；
Step S82, aligning the calibration board coordinate (Xcna) of the calibration board with the suction rodij,Ycnbij) As the suction rod reference coordinates, four suction rod reference coordinates near the arbitrary calibration plate coordinates are acquired, which are (Xcna)ij,Ycnaij)，(Xcnaij+1,Ycnaij+1)，(Xcnai+1j,Ycnai+1j)，(Xcnai+1j+1,Ycnai+1j+1) The corresponding machine coordinate is (Xmac)ij,Ymacij)，(Xmacij+1,Ymacij+1)，(Xmaci+1j,Ymaci+1j)，(Xmaci+1j+1,Ymaci+1j+1) The mechanical coordinates (Xmnc, Ymnc) at which the suction rod is aligned with the coordinates of any calibration plate other than the suction rod reference coordinates in the calibration plate are calculated by the following formula (12):
7. the method of calibrating offset between a pick-up machine camera and a suction rod of claim 1, wherein: in step S4, the effective area of the calibration board covers the working range of the mounting platform, the diameter of the dots in the calibration board is 5mm, and the distance between the centers of two adjacent dots is 10 mm.
8. The method of calibrating offset between a pick-up machine camera and a suction rod of claim 2, wherein: in step S31, the original camera and the add-on camera move along the ziji path.
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