Intelligent fast calibration water jet cutting method

Abstract

The application discloses a kind of intelligent fast calibration water jet cutting method, the calibration method includes: making a mark point on wash basin according to the position of laser horizontal ray, control water jet head moves to several photographing point positions, record the position coordinates of water jet head in each photographing point position as water jet coordinates, the position coordinates of mark point in the image collected by vision module as mark point image coordinates;Water jet head is aimed at mark point and records the position coordinates of water jet head as alignment point coordinates;Using alignment point coordinates and several groups of water jet coordinates, mark point image coordinates, the mapping relationship of image coordinate system to water jet workpiece coordinate system is calculated using mathematical model, to quickly complete the calibration procedure when wash basin cutting.The method provided by the application can simplify and optimize the calibration method, reduce the error problem introduced by manual operation steps, and simultaneously fix the camera on the water jet head to achieve high degree of integration of the vision module, which brings higher precision and stability to the positioning system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of bathroom processing, and particularly relates to an intelligent rapid calibration water jet cutting method. BACKGROUND

[0002] At present, seamless splicing products in the ceramic bathroom industry develop in a large scale. The seamless splicing products are cut by a water jet cutting machine respectively into an upper rock plate and a basin under a table, and then the two are spliced after processing. However, due to the special splicing process and the contour recognition process, the production efficiency still needs to be improved.

[0003] In a Chinese patent with the publication number CN114603489A, a device and method for visually guiding a water jet to intelligently recognize and cut seamless products are disclosed. A plurality of marking points are manually marked at the position to be cut of a washbasin. An image of the washbasin is collected by a visual detection module for processing. The image of the marking points is obtained and coordinate conversion is performed to obtain the workpiece coordinates. The laser curve image coordinates are obtained. The workpiece coordinates are used as drawing points to draw a CAD file of the washbasin cutting line. The water jet cutting machine reads the CAD file and cuts the washbasin according to the washbasin cutting line. In the technical solution of the application, the problems of complex traditional process operation, strong coupling, inaccurate contour recognition, inaccurate calibration, long time consumption, high labor cost, and large influence of environmental factors of traditional ceramic bathroom seamless splicing products are solved.

[0004] In the water jet cutting process, the image coordinates of the washbasin CAD and the water jet workpiece coordinates are converted based on the calibration coordinates. However, manual calibration is prone to errors, and it is often difficult to determine whether the error is due to calibration operation failure, the water jet machine itself, the coordinate conversion process, or other reasons. In most cases, water jet engineers rely on experience to gradually exclude and adjust to achieve the best precision. Therefore, the calibration step method in the prior art is still relatively cumbersome and needs to be improved and optimized to improve production precision and efficiency. At the same time, the visual detection module needs to be installed with a custom camera bracket, which consumes a lot of materials and has high cost, and is easily affected by the imaging effect of the factory site deployment factor. SUMMARY

[0005] The purpose of the present application is to provide an intelligent rapid calibration water jet cutting method to solve the problems in the background art. To achieve the purpose, the technical solution adopted by the present application is:

[0006] An intelligent rapid calibration water jet cutting method, the steps of which are:

[0007] S101: placing a washbasin to be cut on the water jet cutting machine;

[0008] S102: start the vision module, which can establish an image coordinate system according to the collected image;

[0009] S103: place the laser leveler on the cutting plane of the washbasin, and start the laser leveler to emit a circle of horizontal laser lines on the cutting plane of the washbasin;

[0010] S104: mark a mark point on the upper edge of the horizontal laser line, and remove the laser leveler;

[0011] S105: the water jet head drives the vision module to move to a photographing point where the mark point can be photographed, and records the photographing point: the position coordinate of the water jet head is the water jet coordinate, and the position coordinate of the mark point in the image collected by the vision module is the mark point image coordinate; continue to move to generate a plurality of photographing points and record a plurality of sets of corresponding mark point image coordinates and water jet coordinates, align the water jet head with the image center of the mark point and record the position coordinate of the water jet head as the alignment point coordinate, and calculate the mapping relationship from the image coordinate system to the water jet workpiece coordinate system through the alignment point coordinate and a plurality of sets of mark point image coordinates and water jet coordinates, to complete the calibration operation;

[0012] S106: identify the laser trajectory of the washbasin to be cut as an image coordinate in the image coordinate system, and obtain the water jet workpiece coordinate in the water jet workpiece coordinate system according to the mapping relationship, to automatically generate the water jet cutting trajectory with the water jet workpiece coordinate as the drawing point.

[0013] As preferred, the water jet head drives the vision module to move to a photographing point where the mark point can be photographed, and records the photographing point: the position coordinate of the water jet head is the water jet coordinate, and the position coordinate of the mark point in the image collected by the vision module is the mark point image coordinate; continue to move to generate a plurality of photographing points and record a plurality of sets of corresponding mark point image coordinates and water jet coordinates, align the water jet head with the image center of the mark point and record the position coordinate of the water jet head as the alignment point coordinate, and calculate the mapping relationship from the image coordinate system to the water jet workpiece coordinate system through the alignment point coordinate and a plurality of sets of mark point image coordinates and water jet coordinates, to complete the calibration operation, including:

[0014] S1051: run the water jet head, the water jet cutting machine establishes a water jet workpiece coordinate system according to the moving plane of the water jet head, the water jet head drives the vision module to move along the outer edge of the washbasin, the image area obtained by the vision module changes, and the image area captures the mark point;

[0015] S1052: after the water jet head moves to a position where the mark point is located at the corner or edge of the image area, the water jet head stops moving, and the position is taken as a photographing point;

[0016] S1053: record the position coordinates of the water jet head as water jet coordinates and the position coordinates of the mark point in the image collected by the vision module as mark point image coordinates to obtain a set of corresponding mark point image coordinates and water jet coordinates;

[0017] S1054: determine whether i sets (i≥3) of data of water jet coordinates and mark point image coordinates are not equal to each other,

[0018] if not, return to step S1052, and if yes, perform step S1055;

[0019] S1055: control the movement of the water jet head to the center position of the mark point, i.e., the water jet head is aligned with the mark point, and record the position coordinates of the water jet head as alignment point coordinates;

[0020] S1056: calculate the mapping relationship from the image coordinate system to the water jet workpiece coordinate system by using a mathematical model based on the alignment point coordinates and a plurality of sets of corresponding mark point image coordinates and water jet coordinates.

[0021] Preferably, the control of the movement of the water jet head to the center position of the mark point can be:

[0022] controlling the water jet head to vertically spray water flow downward, and moving the water jet head to allow the water flow to hit the center of the mark point.

[0023] Preferably, the control of the movement of the water jet head to the center position of the mark point can also be:

[0024] moving the water jet head to align with or abut against the mark point by the hardware of the water jet head.

[0025] Preferably, the vision module comprises a vision camera and a fixing frame, the vision camera is fixedly installed on the water jet head through the fixing frame, the vision camera is installed perpendicularly to the cutting plane, the vision camera moves along the XY direction under the driving of the water jet head, and the vision camera is controlled by a vision program.

[0026] Preferably, the height of the vision camera and the cutting plane of the washbasin remains unchanged.

[0027] Preferably, the mark point is an obvious pattern, and the graphic center of the mark point is located at the upper edge of the horizontal laser line.

[0028] The present application has the following advantages:

[0029] 1. The rapid calibration method provided by the patent reduces redundant manual operation steps, brings higher precision and stability to the positioning system, eliminates the causes of errors, and simplifies and optimizes the step method. Even if the hardware changes, the calibration can still be quickly completed, and the influence of manual operation error on system precision is reduced to a minimum;

[0030] 2. The rapid calibration method can optimize the hardware structure of the equipment and the hardware setting of the visual module. The camera is fixed on the water jet head, and the environment of the system deployment site does not need to be considered, which improves the integration level of the equipment. At the same time, the position of the camera is low, the imaging effect is good, and the camera and the original structure of the water jet will not collide. The working position of the visual camera can be freely set, and the working range is the reachable range of the water jet head. The visual camera moves with the water jet head, which can offset the coordinate offset of the water jet head. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A flowchart of an intelligent rapid calibration water jet cutting method is provided for the embodiments of the present application.

[0032] Figure 2 A water jet cutting machine structure diagram of an intelligent rapid calibration water jet cutting method is provided for the embodiments of the present application.

[0033] Figure 3 A structure diagram of a water jet head and a visual module in an intelligent rapid calibration water jet cutting method is provided for the embodiments of the present application.

[0034] Figure 4 A rapid calibration step flowchart of an intelligent rapid calibration water jet cutting method is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0035] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the related drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be realized in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0036] It should be noted that when an element is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In addition, it should be noted that when an element is referred to as being "connected", "coupled", or "linked" to another element, it can be directly connected, coupled, or linked to the other element or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. The terms "vertical", "horizontal", "left", "right", and similar expressions as used herein are for illustrative purposes only and are not intended to be limiting. The terms "top", "bottom", "left", "right", "front", "back", and similar expressions as used herein are for illustrative purposes only and are not intended to be limiting.

[0037] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0038] The technical solutions of the patent will be further described in detail in combination with the specific embodiments.

[0039] Referring to Figure 1 , Figure 1 is a flowchart of an intelligent and fast calibration water jet cutting method, and the steps are as follows:

[0040] S101: Place the sink 2 to be cut on the water jet cutting machine 1.

[0041] Referring to Figure 2 , Figure 2 is a structural schematic diagram of the water jet cutting machine 1, the water jet cutting machine 1 is provided with a workbench 3, the sink support 4 is installed on the workbench 3, and the sink 2 is placed on the sink support 4.

[0042] S102: Start the vision module, and the vision module can establish an image coordinate system according to the collected image.

[0043] Referring to Figure 3 , Figure 3 is a structural schematic diagram of the water jet cutting machine 1 and the vision module, the vision module includes a vision camera 6 and a fixing frame 7, the vision camera 6 is fixedly installed on the water jet head 5 through the fixing frame 7, the vision camera 6 is installed perpendicular to the cutting plane, the vision camera 6 moves along the XY direction under the driving of the water jet head 5, the vision camera 6 is controlled through a vision program, and the vision program establishes an image coordinate system;

[0044] S103: Place the laser level 8 on the pre-cutting plane, and start the laser level 8 to emit a circle of horizontal laser lines on the cutting plane of the washbasin 2.

[0045] Wherein, the laser level 8 is placed above the washbasin 2, and emits a circle of horizontal laser lines on the inner side wall of the washbasin 2.

[0046] S104: Mark a mark point on the upper edge of the horizontal laser line, and remove the laser level 8.

[0047] Wherein, the mark point is a clear pattern, and the center of the mark point pattern is located at the upper edge of the horizontal laser line. Specifically, the mark point is a clear dot or cross image or target pattern.

[0048] S105: The water jet head 5 drives the visual module to move to a shooting point where the mark point can be shot, and records the shooting point: the position coordinates of the water jet head 5 are water jet coordinates, and the position coordinates of the mark point in the image collected by the visual module are mark point image coordinates; continue to move to generate three shooting points and record three sets of corresponding mark point image coordinates and water jet coordinates, align the water jet head to the center of the mark point and record the position coordinates of the water jet head as the alignment point coordinates, and calculate the mapping relationship from the image coordinate system to the water jet workpiece coordinate system through the alignment point coordinates and the three sets of mark point image coordinates and water jet coordinates, to complete the calibration operation.

[0049] Wherein, the water jet cutting machine 1 is provided with a driving module, the driving module controls the movement of the water jet head 5, and the water jet cutting machine 1 establishes a water jet workpiece coordinate system according to the movement plane of the water jet head 5; the water jet head 5 and the visual module automatically realize rapid calibration and calibration, which can map the position coordinates in the image coordinate system to the water jet workpiece coordinate system, so that the water jet head 5 can accurately position and move to the actual position of the position coordinates in the water jet workpiece coordinate system.

[0050] S106: Identify the laser trajectory of the washbasin to be cut as image coordinates in the image coordinate system, and obtain water jet workpiece coordinates in the water jet workpiece coordinate system according to the mapping relationship, to automatically generate a water jet cutting trajectory with the water jet workpiece coordinates as the drawing points.

[0051] Wherein, the method of identifying the laser trajectory of the washbasin to be cut as image coordinates can be but is not limited to: using the laser level to emit a trajectory laser to be cut on the washbasin, and identifying and marking the trajectory laser as dense image coordinates through the visual module.

[0052] S107: The water jet cutting machine 1 reads the CAD file and performs cutting when cutting.

[0053] In the embodiment, the water jet head 5 drives the visual module to move to a shooting point position at which the mark point can be shot, and records the shooting point position: the position coordinates of the water jet head 5 are water jet coordinates, and the position coordinates of the mark point in the image collected by the visual module are mark point image coordinates; three shooting point positions are continuously generated to record three sets of corresponding mark point image coordinates and water jet coordinates, the water jet head is aligned to the center of the mark point, and the position coordinates of the water jet head are recorded as alignment point coordinates; the mapping relationship from the image coordinate system to the water jet workpiece coordinate system is calculated through the alignment point coordinates and the three sets of mark point image coordinates and water jet coordinates, and the calibration operation is completed, including:

[0054] Referring to Figure 4 , Figure 4 The flowchart of the quick calibration of the water jet head 5 and the visual module through the mark point.

[0055] S1051: The water jet head 5 is operated, the water jet cutting machine 1 establishes a water jet workpiece coordinate system according to the moving plane of the water jet head 5, the water jet head 5 drives the visual module to move along the outer edge of the hand basin, the image area obtained by the visual module changes, and the mark point is captured in the image area.

[0056] The moving plane of the water jet head 5 and the visual camera 6 is parallel to the cutting plane

[0057] S1052: After the water jet head 5 moves to the position at which the mark point is located at the corner or the edge of the image area, the water jet head 5 stops moving, and the position is taken as a shooting point position.

[0058] S1053: At the shooting point position, the position coordinates of the water jet head 5 are water jet coordinates, the position coordinates of the mark point in the image collected by the visual module are mark point image coordinates, and one set of corresponding mark point image coordinates and water jet coordinates is obtained.

[0059] The water jet coordinates refer to the position coordinates of the water jet head 5 in the water jet workpiece coordinate system when the water jet head 5 moves to the shooting point position; and the mark point image coordinates refer to the position coordinates of the mark point in the image coordinate system at the shooting point position.

[0060] S1054: Whether i sets (i≥3) of data of the water jet coordinates and the mark point image coordinates are different from each other is judged.

[0061] If not, the step S1052 is returned to execute; and if yes, the step S1055 is executed.

[0062] S1055: The water jet head 5 is controlled to move to the center position of the mark point, that is, the water jet head 5 is aligned to the mark point, and the position coordinates of the water jet head 5 are recorded as alignment point coordinates.

[0063] Wherein, the alignment point coordinate refers to the position coordinate of the mark point in the water jet workpiece coordinate system obtained by aligning the mark point through the water jet head 5.

[0064] S1056: The mapping relationship from the image coordinate system to the water jet workpiece coordinate system is calculated by using a mathematical model through the alignment point coordinate and a plurality of sets of corresponding mark point image coordinates and water jet coordinates.

[0065] Wherein, when rapid calibration is performed, one mark point is needed to obtain the water jet coordinates of a plurality of photographing points, the mark point image coordinates of a plurality of photographing point images, and the workpiece coordinates when the water jet head aligns the mark point (alignment point coordinates), so that the coordinate transformation formula of the image coordinates and the water jet coordinates can be obtained. The following is to explain the coordinate transformation mathematical model of the calibration process:

[0066] Let the water jet coordinates of the i-th photographing point (collectively referred to as water jet coordinates) be p r,i =[x r,i ,y r,i ] T ,i≤N, wherein N is the number of photographing points; let the mark point image coordinates of the i-th photographing point image (collectively referred to as mark point image coordinates) be p v,i =[x v,i ,y v,i ] T ,i≤N; the water jet coordinates when the water jet head aligns the mark point (referred to as alignment point coordinates) are p r,0 =[x r,0 ,y r,0 ] T . The water jet coordinates of the image obtained by photographing during visual positioning are denoted as p g =[x g ,y g ] T .

[0067] Wherein, the water jet coordinates p g are the water jet coordinates obtained when the laser image of the trajectory to be cut is acquired after calibration is completed.

[0068] After the above data is obtained, the mapping relationship between the image coordinate system and the water jet workpiece coordinate system can be obtained. For the image coordinates p v =[x v ,y v ] T , the corresponding water jet workpiece coordinates p r =[x r ,y r ] T can be obtained through the following transformation relationship:

[0069] 1. When N<3, the corresponding water jet workpiece coordinates pr i.e.

[0070]

[0071] 2. When N≥3, if the calibration data does not satisfy the formula (*), the corresponding water jet workpiece coordinate p r ,

[0072]

[0073] 3. When N=3, and the formula (*) is satisfied, the corresponding water jet workpiece coordinate p r is obtained by affine transformation approximation, p r = [p r,1 -p r,2 , p r,1 -p r,3 ] [p v,2 -p v,1 , p v,3 -p v,1 ] -1 (p v -p v,1 ) + p r,0 + p g -p r,1

[0074] 4. When N>3, and the formula (*) is satisfied, the image coordinate p v and the corresponding water jet workpiece coordinate p r have homography, that is, the following relationship exists:

[0075]

[0076] where H is a homography matrix:

[0077]

[0078] The homography matrix is vectorized into a homography parameter vector:

[0079]

[0080] The mark point water jet offset coordinates are defined using the alignment point coordinates as follows:

[0081]

[0082] Therefore, the calibration data can be used to construct the following homogeneous linear equations:

[0083] Ah=b

[0084] where:

[0085]

[0086]

[0087] The homographic parameter vector h is calculated by least square method:

[0088] h = (A T A) -1 A T b

[0089] The calculation formula of the corresponding water jet workpiece coordinate p r is:

[0090]

[0091] In the embodiment, the control of the mobile water jet head 5 to the center position of the mark point is as follows: the water jet head 5 is controlled to vertically downwardly spray water flow, and the mobile water jet head 5 is controlled to make the water flow hit the center of the mark point.

[0092] The control of the water jet head 5 to the center position of the mark point can also be as follows: the water jet head 5 is moved to align with or abut against the mark point through the hardware of the water jet head 5.

[0093] The above embodiments are only used for illustrating the present application, but not for limiting the present application. The ordinary skilled in the related art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all the equivalent technical solutions belong to the scope of the present application, and the patent protection scope of the present application should be defined by the claims.

Claims

1. A smart and rapid calibration method for waterjet cutting, characterized in that, The steps are as follows: S101: Place the washbasin to be cut on the waterjet cutter; S102: Start the vision module, which establishes an image coordinate system based on the acquired images; S103: Place the laser level on the plane to be cut, and turn on the laser level to irradiate a horizontal laser line around the cutting plane of the washbasin; S104: Mark a point at the upper edge of the horizontal laser line, then remove the laser level. S105: The waterjet head moves the vision module to a shooting point where the marked point can be captured, and records the shooting point: the position coordinates of the waterjet head are the waterjet coordinates, and the position coordinates of the marked point in the image captured by the vision module are the marked point image coordinates; continue moving to generate several shooting points and record several sets of corresponding marked point image coordinates and waterjet coordinates, align the waterjet head with the center of the marked point and record the position coordinates of the waterjet head as the alignment point coordinates, and calculate the mapping relationship from the image coordinate system to the waterjet workpiece coordinate system through the alignment point coordinates and several sets of marked point image coordinates and waterjet coordinates, thus completing the calibration operation; S106: The laser trajectory of the washbasin to be cut is identified as the image coordinates in the image coordinate system. The image coordinates are used to obtain the water jet workpiece coordinates in the water jet workpiece coordinate system according to the mapping relationship. The water jet cutting trajectory is automatically generated with the water jet workpiece coordinates as the drawing point. The waterjet head moves the vision module to a photographing point where the marked point can be captured, and records this photographing point: the position coordinates of the waterjet head are the waterjet coordinates, and the position coordinates of the marked point in the image captured by the vision module are the marked point image coordinates; the movement continues to generate several photographing points and records several sets of corresponding marked point image coordinates and waterjet coordinates; the waterjet head is aligned with the center of the marked point and the position coordinates of the waterjet head are recorded as the alignment point coordinates; through the alignment point coordinates and several sets of marked point image coordinates and waterjet coordinates, the mapping relationship from the image coordinate system to the waterjet workpiece coordinate system is calculated, completing the calibration operation, including: S1051: The waterjet head is operated, and the waterjet cutting machine establishes a waterjet workpiece coordinate system according to the moving plane of the waterjet head. The waterjet head drives the vision module to move along the outer edge of the washbasin. The image area acquired by the vision module changes accordingly, and the image area captures the marker point. S1052: After the water jet head moves to the corner or edge of the image area where the marked point is located, the water jet head stops moving and the position is taken as the photo taking point; S1053: When the photo is taken at the point of view, the position coordinates of the water jet head are water jet coordinates, and the position coordinates of the marker point in the image acquired by the vision module are marker point image coordinates, thus obtaining a set of mutually corresponding marker point image coordinates and water jet coordinates. S1054: Determine whether i sets (i≥3) of data have different water jet coordinates and marker point image coordinates. If not, return to step S1052; if yes, execute step S1055. S1055: Control the movement of the water jet head to the center position of the marker point, that is, the water jet head is aligned with the marker point, and record the position coordinates of the water jet head as the alignment point coordinates. S1056: Using the alignment point coordinates and several sets of corresponding marker point image coordinates and water jet coordinates, a mathematical model is used to calculate the mapping relationship from the image coordinate system to the water jet workpiece coordinate system. Controlling the water jet head to the center position of the marked point involves: controlling the water jet head to spray water vertically downwards, and moving the water jet head so that the water jet hits the center of the marked point.

2. The intelligent rapid calibration waterjet cutting method according to claim 1, characterized in that, Controlling the movement of the water jet head to the center position of the marker point involves moving the water jet head to align with or press against the marker point using the hardware of the water jet head.

3. The intelligent rapid calibration waterjet cutting method according to claim 1, characterized in that, The vision module includes a vision camera and a mounting bracket. The vision camera is fixedly mounted on the waterjet head via the mounting bracket. The vision camera is installed perpendicular to the plane to be cut. The vision camera moves along the XY direction under the drive of the waterjet head. The vision camera is controlled by a vision program.

4. The intelligent rapid calibration waterjet cutting method according to claim 1, characterized in that, The marker point is a distinct pattern, and the center of the pattern of the marker point is located at the upper edge of the horizontal laser line.

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