Method for automatically correcting the position deviation between camera and nozzle

Abstract

The invention discloses a method for automatically correcting the position deviation between a camera and a nozzle, comprising the following steps: the first step, parameter configuration; the second step, starting correction; the third step, calculating the mechanical coordinates of the nozzle when discharging glue on an axis perpendicular to a working plane; the fourth step, discharging glue by the nozzle; the fifth step, taking pictures with a camera; the sixth step, calculating the pixel deviation between the pixel center of a glue point and the pixel center of a camera; the seventh step, calculating the mechanical coordinates at which the mechanical center of the camera coincides with the mechanical center of the glue point; the eighth step, calculating the mechanical deviation between the mechanical center of the nozzle and the mechanical center of the camera, and completing calibration; the method identifies the center of the glue point through a visual image algorithm, thereby reducing errors caused by human factors and improving the final process accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of automatic correction of glue dispensing machines, in particular to a method for automatically correcting position deviations between a camera and a nozzle. Background Art

[0002] In the glue dispenser software system, you need to use the camera center to view the product and set the glue spraying route. When you actually use the nozzle to spray glue, although the nozzle and the camera center are in the XY plane of the machine, they are not in the same position. The camera is fixed in position when it is not disassembled. After each installation of the nozzle in the glue dispenser, the nozzle position will change slightly. Therefore, after each installation of the nozzle, the camera center / nozzle center must be calibrated to confirm its deviation in the XY plane.

[0003] The usual practice in the industry is to move the nozzle to a certain position in the pre-set process area, spray a drop of glue, and then use the camera center to visually align the camera center with the glue center, record the camera position at this time, calculate the xy coordinate deviation between the glue spraying position and the camera position, and keep a record for subsequent use. However, in the traditional method, manual visual observation is required to align the camera center with the glue dot center. However, everyone has different standards for perceiving the glue dot center, and there is a large subjective error in visually observing the glue dot center, which will also lead to a large error in the calibration result. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art.

[0005] To this end, the present invention proposes a method for automatically correcting the position deviation between the camera and the nozzle, identifying the center of the glue dot through a visual image algorithm, thereby reducing the error caused by human factors and improving the final process accuracy.

[0006] The method for automatically correcting the position deviation between a camera and a nozzle according to an embodiment of the present invention comprises the following steps:

[0007] Step 1: Parameter configuration: Configure parameters in the job control flow module of the software system.

[0008] On the work plane, set a glue spraying position;

[0009] Set the nozzle spray height to mm, the glue spraying height is the height difference between the nozzle end and the glue spraying surface;

[0010] Set the number of nozzle glue points to Drops, among them, is greater than or equal to A positive integer of ;

[0011] Set the mechanical deviation between the tool setting surface and the glue spraying surface on the axis perpendicular to the working plane;

[0012] Set the pixel equivalent of the dispensing machine to mm / pixel;

[0013] During initial use, manually calibrate the mechanical measurement deviation between the camera mechanical center and the nozzle mechanical center on the working plane;

[0014] Step 2, start calibration: After starting calibration, the dispensing machine obtains the set initial tool setting position and performs the normal tool setting process. On the axis perpendicular to the working plane, the mechanical coordinates of the nozzle when the nozzle is in contact with the surface of the tool setting instrument are obtained;

[0015] Step 3: Calculate the mechanical coordinates of the nozzle when discharging glue on the axis perpendicular to the working plane;

[0016] Step 4: Glue discharge from nozzle: The nozzle is moved to the top of the glue discharge position set in step 1, and the nozzle height is moved to the mechanical coordinate position calculated in step 3, and the glue discharge points are set. Glue out;

[0017] Step 5, taking a picture with a camera: after the glue spraying is completed, the camera is moved to the top of the glue spraying position set in the first step to take a picture, obtain a photographic image, and record the photographic position of the camera at this time. The photographic position of the camera is the mechanical center position of the camera, wherein the photographic position of the camera is obtained by subtracting the mechanical measurement deviation between the mechanical center of the camera and the mechanical center of the nozzle from the glue spraying position set in the first step;

[0018] Step 6: Calculate the pixel deviation between the glue point pixel center and the camera pixel center: The visual algorithm performs circle fitting on the glue point based on the photographed image, calculates the center of the fitted circle, and the center of the fitted circle is the glue point pixel center. The glue point pixel center in the photographed image and the pixel center of the photographed image are identified. , the pixel center of the photographed image That is the camera pixel center, and then the pixel deviation between the glue point pixel center and the camera pixel center is calculated;

[0019] Step 7: Calculate the mechanical coordinates where the mechanical center of the camera coincides with the mechanical center of the glue point:

[0020] First, calculate the mechanical deviation between the mechanical center of the glue point and the mechanical center of the camera, where the mechanical deviation is obtained by multiplying the pixel deviation between the pixel center of the glue point and the pixel center of the camera calculated in step 6 by the pixel equivalent. Then, the mechanical center of the glue point is calculated, and the mechanical center of the glue point is obtained by subtracting the mechanical deviation between the mechanical center of the glue point and the mechanical center of the camera from the camera shooting position in the fifth step;

[0021] Step 8: Calculate the mechanical deviation between the nozzle mechanical center and the camera mechanical center. The mechanical deviation is obtained by subtracting the camera position in step 5 from the glue point mechanical center obtained in step 7. Finally, the calibration is completed.

[0022] The beneficial effect of the present invention is that after the glue dot is generated, a camera is used to capture the glue dot image, and a visual algorithm is used to perform circle fitting on the glue dot, and the center of the fitting circle is calculated, thereby calculating the XY deviation between the glue dot center and the camera center. The glue dot center identified by the visual image algorithm is more accurate and stable than visual identification, thereby reducing errors caused by human factors and improving the final process accuracy.

[0023] According to one embodiment of the present invention, when the camera and the nozzle are both installed vertically, the deviation between the camera and the nozzle in the XY plane is automatically corrected.

[0024] According to one embodiment of the present invention, in the first step, the mechanical coordinates of a glue spraying position are set to ; Set the mechanical deviation between the tool setting surface and the glue spraying surface in the Z-axis direction to mm; Manually calibrate the mechanical measurement deviation between the camera mechanical center and the nozzle mechanical center in the XY plane ;

[0025] In the second step, the Z-axis coordinate of the nozzle when the nozzle is attached to the surface of the tool setting instrument is obtained. ;

[0026] In the third step, the Z-axis coordinate of the nozzle when discharging glue is calculated :according to , and calculate ;

[0027] In the fourth step, the nozzle is moved to position, and the height is moved to The position of the glue point is set according to the number of glue points Glue out;

[0028] In step 5, the camera moves to Take a photo above the position, obtain the photo image, and record the photo position of the camera at this time ,in, , ;

[0029] In step 6, the center of the fitted circle is calculated , that is, identify the center of the glue point pixel in the photographed image and the pixel center of the photographed image , and then calculate the glue point pixel center Centered with camera pixel Pixel deviation ,in, , ;

[0030] In step 7, the mechanical coordinates of the camera mechanical center and the glue point mechanical center are calculated. :First calculate the mechanical center of the glue point With camera mechanical center Mechanical deviation ,in, , ; Then calculate the mechanical center of the glue point ,in, , ;

[0031] In step 8, the mechanical deviation between the nozzle mechanical center and the camera mechanical center is calculated. : , .

[0032] According to one embodiment of the present invention, in the third step, when the tool setting instrument surface and the glue spraying surface are at the same height, that is, When .

[0033] According to one embodiment of the present invention, in the third step, when the tool setting instrument surface is higher than the glue spraying surface, .

[0034] According to one embodiment of the present invention, in the third step, when the tool setting instrument surface is lower than the glue spraying surface, .

[0035] According to one embodiment of the present invention, when the camera and the nozzle are both installed horizontally, and the axis of the camera and the axis of the nozzle are parallel to the Y axis, the deviation of the camera and the nozzle in the XZ plane is automatically corrected.

[0036] According to one embodiment of the present invention, when the camera and the nozzle are both installed horizontally, and the axis of the camera and the axis of the nozzle are parallel to the X-axis, the deviation of the camera and the nozzle in the YZ plane is automatically corrected.

[0037] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0040] Figure 1 is a flow chart of the present invention;

[0041] Figure 2 It is a schematic diagram of the structure in which the camera and the nozzle are installed vertically.

[0042] The symbols in the figure are: 1. Nozzle; 2. Camera; 3. Tool setting instrument; 4. Calibration plate. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] In the description of the present invention, it is necessary to understand that the orientations or positional relationships indicated by the terms “one side”, “the other side”, “both sides”, “between”, “middle”, “upper end”, “lower end”, etc. are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0045] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be directly connected or indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The method for automatically correcting the position deviation between the camera and the nozzle according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] See Figure 1 The method for automatically correcting the position deviation between the camera and the nozzle of the present invention comprises the following steps:

[0048] Step 1: Parameter configuration: Configure parameters in the job control flow module of the software system.

[0049] On the work plane, set a glue spraying position;

[0050] Set the spray height of nozzle 1 to mm, the glue spraying height is the height difference between the end of nozzle 1 and the glue spraying surface; is a process parameter, and the glue spraying surface can be the surface of the calibration plate 4 or the surface of the product to be glue sprayed.

[0051] Set the number of glue points of nozzle 1 to Drops, among them, is greater than or equal to A positive integer; the number of glue points Freely set according to user needs: when the glue is thicker, The circle formed by a drop of glue may be very small, so you need to spray a few more drops. These drops of glue are sprayed on the same position. After these drops of glue flow, they can form a circle that meets the requirements; when the glue is relatively thin, it may The circle formed by the flowing glue can meet the requirements.

[0052] On an axis perpendicular to the working plane, set the mechanical deviation between the tool setting probe 3 surface and the glue spraying surface;

[0053] Set the pixel equivalent of the dispensing machine to mm / pixel;

[0054] During initial use, manually calibrate the mechanical measurement deviation between the mechanical center of camera 2 and the mechanical center of nozzle 1 on the working plane with an accuracy of millimeters;

[0055] Step 2, start calibration: After starting calibration, the dispensing machine obtains the set initial tool setting position and performs the normal tool setting process. On the axis perpendicular to the working plane, the mechanical coordinates of the nozzle 1 when the nozzle 1 is attached to the surface of the tool setting instrument 3 are obtained;

[0056] Step 3: Calculate the mechanical coordinates of nozzle 1 when discharging glue on an axis perpendicular to the working plane;

[0057] Step 4: Nozzle 1 dispensing glue: Nozzle 1 moves to the top of the dispensing position set in step 1, and the height of nozzle 1 moves to the mechanical coordinate position calculated in step 3, and the number of dispensing points is set. Glue out;

[0058] Step 5, taking a picture with camera 2: after the glue spraying is completed, camera 2 is moved to the top of the glue spraying position set in step 1 to take a picture, obtain a photographic image, and record the photographic position of camera 2 at this time. The photographic position of camera 2 is the mechanical center position of camera 2, wherein the photographic position of camera 2 is obtained by subtracting the mechanical measurement deviation between the mechanical center of camera 2 and the mechanical center of nozzle 1 from the glue spraying position set in step 1;

[0059] Step 6: Calculate the pixel deviation between the glue point pixel center and the camera 2 pixel center: The visual algorithm performs circle fitting on the glue point based on the photographed image, calculates the center of the fitted circle, and the center of the fitted circle is the glue point pixel center. The glue point pixel center in the photographed image and the pixel center of the photographed image are identified. , the pixel center of the photographed image That is the pixel center of camera 2, and then the pixel deviation between the pixel center of the glue point and the pixel center of camera 2 is calculated;

[0060] Step 7: Calculate the mechanical coordinates where the mechanical center of camera 2 coincides with the mechanical center of the glue point:

[0061] First, calculate the mechanical deviation between the mechanical center of the glue point and the mechanical center of camera 2. The mechanical deviation is calculated by multiplying the pixel deviation between the pixel center of the glue point and the pixel center of camera 2 calculated in step 6 by the pixel equivalent. Then calculate the mechanical center of the glue point, which is obtained by subtracting the mechanical deviation between the mechanical center of the glue point and the mechanical center of the camera 2 from the camera 2 shooting position in step 5;

[0062] Step 8: Calculate the mechanical deviation between the mechanical center of nozzle 1 and the mechanical center of camera 2. The mechanical deviation is obtained by subtracting the shooting position of camera 2 in step 5 from the mechanical center of the glue point obtained in step 7. Finally, the calibration is completed.

[0063] The method for automatically correcting the position deviation between the camera and the nozzle is applicable to the case where the camera 2 and the nozzle 1 are both installed vertically, and is also applicable to the case where the camera 2 and the nozzle 1 are both installed horizontally.

[0064] 1. If Figure 2 As shown, when the camera 2 and the nozzle 1 are both installed vertically, the deviation between the camera 2 and the nozzle 1 in the XY plane is automatically corrected, which specifically includes the following steps:

[0065] Step 11: Parameter configuration: Configure parameters in the job control flow module of the software system.

[0066] On the work plane, set a glue spraying position. The mechanical coordinates of the glue spraying position are ;

[0067] Set the spray height of nozzle 1 to mm, the glue spraying height is the height difference between the end of nozzle 1 and the glue spraying surface;

[0068] Set the number of glue points of nozzle 1 to Drops, among them, is greater than or equal to A positive integer of ;

[0069] On the axis perpendicular to the working plane, set the mechanical deviation between the tool setting probe 3 surface and the glue spraying surface in the Z-axis direction to mm; among which, is the process standard deviation.

[0070] Set the pixel equivalent of the dispensing machine to mm / pixel; for example: mm / pixel, i.e. Pixels = Mm.

[0071] On the work plane, manually calibrate the mechanical measurement deviation between the mechanical center of camera 2 and the mechanical center of nozzle 1 in the XY plane ;

[0072] Step 21, start calibration: After starting calibration, the dispensing machine obtains the set initial tool setting position and performs the normal tool setting process. On the axis perpendicular to the working plane, the Z-axis coordinate of nozzle 1 when nozzle 1 is attached to the surface of tool setting instrument 3 is obtained. ;

[0073] Step 31: Calculate the Z-axis coordinate of nozzle 1 when discharging glue on the axis perpendicular to the working plane :according to , and calculate ;

[0074] Case 1: When the surface of the tool setting instrument 3 is at the same height as the glue spraying surface, that is, When For example: when mm, mm, then Mm.

[0075] Case 2: When the surface of the tool setting instrument 3 is higher than the glue spraying surface, For example: when mm, mm, mm, then Mm.

[0076] Case 3: When the surface of the tool setting instrument 3 is lower than the glue spraying surface, For example: when mm, mm, mm, then Mm.

[0077] Step 41, nozzle 1 discharging glue: nozzle 1 moves to position, and the height is moved to The position of the glue point is set according to the number of glue points Glue out;

[0078] Step 51, camera 2 takes pictures: After the glue spraying is completed, camera 2 moves to Take a picture above the position to obtain a picture image and record the picture taking position of camera 2 at this time , where the camera 2's photo position is The calculation of is shown in formula (1):

[0079] (1)

[0080] Step 61: Calculate the pixel deviation between the glue point pixel center and the camera 2 pixel center: The visual algorithm performs circle fitting on the glue point based on the photographed image and calculates the center of the fitted circle. , that is, identify the center of the glue point pixel in the photographed image and the pixel center of the photographed image , and then calculate the glue point pixel center Centered with camera 2 pixels Pixel deviation , where pixel deviation The calculation of is shown in formula (2):

[0081] (2)

[0082] Step 71: Calculate the mechanical coordinates of the camera 2 mechanical center and the glue point mechanical center. :

[0083] Calculate the mechanical center of the glue point first Mechanical center with camera 2 Mechanical deviation , where mechanical deviation The calculation of is shown in formula (3):

[0084] (3)

[0085] Recalculate the glue point mechanical center , among which, glue point mechanical center The calculation of is shown in formula (4):

[0086] (4)

[0087] Step 81: Calculate the mechanical deviation between the mechanical center of nozzle 1 and the mechanical center of camera 2 , mechanical deviation The calculation of is shown in formula (5):

[0088] (5)

[0089] Final calibration completed.

[0090] 2. When the camera 2 and the nozzle 1 are both installed horizontally, and the axis of the camera 2 and the axis of the nozzle 1 are parallel to the Y axis, the deviation of the camera 2 and the nozzle 1 in the XZ plane is automatically corrected.

[0091] 3. When the camera 2 and the nozzle 1 are both installed horizontally, and the axis of the camera 2 and the axis of the nozzle 1 are parallel to the X-axis, the deviation of the camera 2 and the nozzle 1 in the YZ plane is automatically corrected.

[0092] The method for automatically correcting the position deviation between the camera and the nozzle uses camera 2 to capture the glue dot image after the glue dot is generated, and adopts a visual algorithm to perform circle fitting on the glue dot and calculate the center of the fitting circle, thereby calculating the XY deviation between the glue dot center and the center of camera 2. The glue dot center identified by the visual image algorithm is more accurate and stable than visual identification, thereby reducing errors caused by human intervention and improving the final process accuracy.

[0093] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for automatically correcting the position deviation between a camera and a nozzle, characterized in that: The following steps are involved: Step 1: Parameter configuration: Configure parameters in the job control flow module of the software system. On the work plane, set a glue spraying position; Set the nozzle spray height to mm, the glue spraying height is the height difference between the nozzle end and the glue spraying surface; Set the mechanical deviation between the tool setting surface and the glue spraying surface in the Z-axis direction to mm; Set the number of nozzle glue points to Drops, among them, is greater than or equal to A positive integer of ; Set the mechanical deviation between the tool setting surface and the glue spraying surface on the axis perpendicular to the working plane; Set the pixel equivalent of the dispensing machine to mm / pixel; During initial use, manually calibrate the mechanical measurement deviation between the camera mechanical center and the nozzle mechanical center on the working plane; Step 2, start calibration: After starting calibration, the dispensing machine obtains the set initial tool setting position and performs the normal tool setting process. On the axis perpendicular to the working plane, the mechanical coordinates of the nozzle when the nozzle fits the tool setting instrument surface are obtained; the Z-axis coordinates of the nozzle when the nozzle fits the tool setting instrument surface are obtained. ; Step 3: Calculate the mechanical coordinates of the nozzle when discharging glue on the axis perpendicular to the working plane; calculate the Z-axis coordinates of the nozzle when discharging glue :according to , and calculate ; Step 4: Glue discharge from nozzle: The nozzle is moved to the top of the glue discharge position set in step 1, and the nozzle height is moved to the mechanical coordinate position calculated in step 3, and the glue discharge points are set. Glue out; Step 5, taking a picture with a camera: after the glue spraying is completed, the camera is moved to the top of the glue spraying position set in the first step to take a picture, obtain a photographic image, and record the photographic position of the camera at this time. The photographic position of the camera is the mechanical center position of the camera, wherein the photographic position of the camera is obtained by subtracting the mechanical measurement deviation between the mechanical center of the camera and the mechanical center of the nozzle from the glue spraying position set in the first step; Step 6: Calculate the pixel deviation between the glue point pixel center and the camera pixel center: The visual algorithm performs circle fitting on the glue point based on the photographed image, calculates the center of the fitted circle, and the center of the fitted circle is the glue point pixel center. The glue point pixel center in the photographed image and the pixel center of the photographed image are identified. , the pixel center of the photographed image That is the camera pixel center, and then the pixel deviation between the glue point pixel center and the camera pixel center is calculated; Step 7: Calculate the mechanical coordinates where the mechanical center of the camera coincides with the mechanical center of the glue point: First, calculate the mechanical deviation between the mechanical center of the glue point and the mechanical center of the camera, where the mechanical deviation is obtained by multiplying the pixel deviation between the pixel center of the glue point and the pixel center of the camera calculated in step 6 by the pixel equivalent. Then, the mechanical center of the glue point is calculated, and the mechanical center of the glue point is obtained by subtracting the mechanical deviation between the mechanical center of the glue point and the mechanical center of the camera from the camera shooting position in the fifth step; Step 8: Calculate the mechanical deviation between the nozzle mechanical center and the camera mechanical center. The mechanical deviation is obtained by subtracting the camera position in step 5 from the glue point mechanical center obtained in step 7. Finally, the calibration is completed.

2. The method for automatically correcting the position deviation between the camera and the nozzle according to claim 1, characterized in that: When the camera and nozzle are installed vertically, the deviation between the camera and nozzle in the XY plane is automatically corrected.

3. The method for automatically correcting the position deviation between the camera and the nozzle according to claim 2, characterized in that: In the first step, the mechanical coordinates of a spraying position are set as ; Manually calibrate the mechanical measurement deviation between the camera mechanical center and the nozzle mechanical center in the XY plane ; In the fourth step, the nozzle is moved to position, and the height is moved to The position of the glue point is set according to the number of glue points Glue out; In step 5, the camera moves to Take a photo above the position, obtain the photo image, and record the photo position of the camera at this time ,in, , ; In step 6, the center of the fitted circle is calculated , that is, identify the center of the glue point pixel in the photographed image and the pixel center of the photographed image , and then calculate the glue point pixel center Centered with camera pixel Pixel deviation ,in, , ; In step 7, the mechanical coordinates of the camera mechanical center and the glue point mechanical center are calculated. :First calculate the mechanical center of the glue point With camera mechanical center Mechanical deviation ,in, , ; Then calculate the mechanical center of the glue point ,in, , ; In step 8, the mechanical deviation between the nozzle mechanical center and the camera mechanical center is calculated. : , .

4. The method for automatically correcting the position deviation between the camera and the nozzle as claimed in claim 3, characterized in that: In the third step, when the tool setting instrument surface is at the same height as the glue spraying surface, that is, When .

5. The method for automatically correcting the position deviation between the camera and the nozzle as claimed in claim 3, characterized in that: In the third step, when the tool setting surface is higher than the glue spraying surface, .

6. The method for automatically correcting the position deviation between the camera and the nozzle as claimed in claim 3, characterized in that: In the third step, when the tool setting surface is lower than the glue spraying surface, .

7. The method for automatically correcting the position deviation between the camera and the nozzle as claimed in claim 1, characterized in that: When the camera and the nozzle are installed horizontally, and the axis of the camera and the axis of the nozzle are parallel to the Y axis, the deviation of the camera and the nozzle in the XZ plane is automatically corrected.

8. The method for automatically correcting the position deviation between a camera and a nozzle as claimed in claim 1, characterized in that: When the camera and the nozzle are installed horizontally, and the axis of the camera and the axis of the nozzle are parallel to the X-axis, the deviation of the camera and the nozzle in the YZ plane is automatically corrected.

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