Water jet machining verticality calibration method and calibration device

Abstract

The present invention discloses a method and device for calibrating verticality in water jet machining, comprising: calibrating the rotation angle between a first camera, a second camera, and a work platform; calibrating a first mapping relationship between the change in the detection angle of the first camera and the change in the first adjustment angle, and calibrating a second mapping relationship between the change in the detection angle of the second camera and the change in the second adjustment angle; calibrating the jet angle μ based on the first rotation angle and the first mapping relationship; calibrating the jet angle γ based on the second rotation angle and the second mapping relationship; and repeating the calibration process until the change in the first adjustment angle and the change in the second adjustment angle are both less than a convergence threshold λ, completing the calibration. This method is not limited by the mounting angles of the two cameras, nor by whether the workpiece surface is perpendicular to the Z-axis, and can improve the accuracy of water jet verticality calibration relative to the workpiece during machining.

Description

Technical Field

[0001] The present invention relates to the technical field of water-guided laser processing, and in particular to a water jet processing verticality calibration method and calibration device. Background Art

[0002] Water-guided laser processing technology is an advanced process that couples lasers into high-pressure water jets through tiny nozzles. The water jet plays a role similar to optical fiber in this process, effectively guiding the laser beam and transmitting it to the workpiece surface with high precision and high energy density, achieving fine cutting.

[0003] In water-guided laser processing systems, the nozzle is a key component of light-water coupling, and its alignment accuracy directly determines whether the laser can be transmitted stably and effectively. Ideally, the laser should enter the water column strictly coaxially, and the water jet should be perpendicular to the working platform to form a stable and straight light-guiding channel. However, in actual operation, the nozzle is very prone to wear and clogging due to long-term use and needs to be replaced regularly. Although nozzle replacement is a routine operation, due to slight eccentricity in manufacturing or installation, it is easy to cause the water jet to deviate from the ideal axis and form an inclination angle with the working surface. If the angle calibration is not performed in time, the following adverse consequences may occur: the cutting seam will be tilted and the cross-section will have a significant taper; the upper and lower openings will be inconsistent in size, affecting the assembly accuracy; the processing trajectory will be difficult to reproduce, affecting the consistency of the workpiece; it will lead to cutting failures, increased rework rate, and product waste.

[0004] At present, the methods for calibrating the verticality of water jet processing in water-guided laser processing systems mainly include the following:

[0005] Method 1: Manual measurement and adjustment,

[0006] The verticality between the water jet and the platform is determined visually or with the aid of auxiliary tools, and the nozzle or processing head posture is manually adjusted. This method is simple to operate and low-cost, but its correction accuracy depends on the operator's experience, has poor repeatability, and low adjustment efficiency, making it difficult to meet high-precision processing requirements.

[0007] Method 2: Triangulation positioning based on touch sensors,

[0008] This method controls the water jet to contact the sensor at multiple height points in the X and Y directions, calculates the water jet offset angle based on trigonometric relationships, and drives a micro-motion mechanism to adjust the machining head's posture. This method demonstrates good theoretical accuracy and correction reliability, but practical applications present the following challenges: The operational process is cumbersome, requiring multiple sampling and calculation comparisons; It places high demands on sensor accuracy and response speed, resulting in high system costs; and a long adjustment cycle makes it difficult to meet production needs.

[0009] In addition, the existing calibration method cannot achieve a good calibration effect when the workpiece surface is not perpendicular to the Z axis. Summary of the Invention

[0010] The technical problem solved by the present invention is that the existing water jet machining verticality calibration method has the problems of cumbersome operation, low calibration efficiency, and inability to cope with the situation where the workpiece surface is not perpendicular to the Z axis.

[0011] To this end, the present invention provides a water jet machining verticality calibration method and calibration device, which can improve the calibration efficiency and calibration accuracy of the water jet machining verticality calibration.

[0012] The water jet machining verticality calibration method according to an embodiment of the present invention includes the following steps:

[0013] S1. Calibrate the first rotation angle between the first camera and the work platform , calibrate the second rotation angle between the second camera and the work platform , the first camera and the second camera are at an angle set up;

[0014] S2. Calibrate a first mapping relationship between a change in the detection angle of the water jet by the first camera and a change in a first adjustment angle of the water jet, and calibrate a second mapping relationship between a change in the detection angle of the water jet by the second camera and a change in a second adjustment angle of the water jet;

[0015] S3. The first camera obtains the jet angle of the water jet , combined with the first rotation angle ,Will Substitute the first mapping relationship to obtain the change in the first adjustment angle, and the angle adjustment mechanism adjusts the jet angle according to the change in the first adjustment angle. Calibrate so that the jet angle In the image captured by the first camera, state;

[0016] S4. The second camera obtains the jet angle of the water jet , combined with the second rotation angle ,Will Substitute the second mapping relationship to obtain the change in the second adjustment angle, and the angle adjustment mechanism adjusts the jet angle according to the change in the second adjustment angle. Calibrate so that the jet angle In the image captured by the second camera state;

[0017] S5, repeat steps S3-S4 until the change in the first adjustment angle and the change in the second adjustment angle are both less than the convergence threshold , calibration is completed.

[0018] The beneficial effect of the present invention is that, by calibrating the rotation angle between the camera and the working platform, calibrating the mapping relationship between the camera detection angle change and the adjustment angle change, and then using the calibration result to adjust the jet angle, on the one hand, it can improve the calibration efficiency and calibration accuracy of the verticality of water jet processing. On the other hand, the calibration result will not be affected by the tilt of the working platform itself (that is, the workpiece surface is not perpendicular to the Z axis), which can further improve the calibration accuracy of the verticality of the water jet relative to the workpiece surface during processing, which is beneficial to improving the cutting accuracy and cutting quality.

[0019] According to one embodiment of the present invention, a first rotation angle between the first camera and the work platform is calibrated. ,include:

[0020] S1.1. Place the calibration block vertically on the work platform and move it into the field of view of the first camera. The first camera captures an image of the calibration block.

[0021] S1.2, performing edge detection on the calibration block in the calibration block image and extracting the left edge line and the right edge line of the calibration block by straight line fitting;

[0022] S1.3, according to the left edge line and the right edge line of the calibration block, obtain the center line L1 of the calibration block, obtain the center line L2 of the calibration block image in the vertical direction, the first rotation angle is the direction vector of the center line L1 The angle between it and the midline L2, .

[0023] According to one embodiment of the present invention, a first rotation angle between the first camera and the work platform is calibrated. , also includes:

[0024] S1.4. Move the calibration block multiple times along the X and Y directions on the work platform, and calculate the first rotation angle each time it moves. , multiple first rotation angles The mean of is taken as the final first rotation angle between the first camera and the work platform.

[0025] According to one embodiment of the present invention, calibrating a first mapping relationship between a change in a detection angle of the water jet by the first camera and a change in a first adjustment angle of the water jet includes:

[0026] S2.1. Changing the first adjustment angle N times, with the angle changed each time being the same, and capturing N images of the water jet after the first adjustment angle is changed;

[0027] S2.2. Calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the first adjustment angle is changed for the i-th time, i=1,2,3,...,N; represents the component of the direction vector of the water jet in the X direction when the first adjustment angle is changed for the i-th time, represents the component of the direction vector of the water jet in the Y direction when the first adjustment angle is changed for the i-th time;

[0028] S2.3. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the first adjustment angle is changed for the i+1th time, represents the water jet direction angle when the first adjustment angle is changed for the i-th time, and the angle change A linear fit is performed with the variation of the first adjustment angle to obtain a first mapping relationship between the variation of the detection angle of the first camera and the variation of the first adjustment angle.

[0029] According to one embodiment of the present invention, calibrating a second mapping relationship between a change in a detection angle of the water jet by the second camera and a change in a second adjustment angle of the water jet includes:

[0030] S2.4. Change the second adjustment angle N times, each change being the same, and capture N images of the water jet after the second adjustment angle is changed.

[0031] S2.5. Calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the second adjustment angle is changed for the jth time, j=1,2,3,...,N; It represents the component of the direction vector of the water jet in the X direction when the second adjustment angle is changed for the jth time, represents the component of the direction vector of the water jet in the Y direction when the second adjustment angle is changed for the jth time;

[0032] S2.6. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the second adjustment angle is changed for the j+1th time, represents the water jet direction angle when the second adjustment angle is changed for the jth time, and the angle change A linear fit is performed with the variation of the second adjustment angle to obtain a second mapping relationship between the variation of the detection angle of the second camera and the variation of the second adjustment angle.

[0033] According to one embodiment of the present invention, step S5 specifically includes:

[0034] Set the change of the first adjustment angle and the change of the second adjustment angle to be continuously less than the convergence threshold The number threshold n is set, and the initial value of the real-time number m is set to 0;

[0035] The jet angle and the first rotation angle Substitute the change of the first adjustment angle calculated in the first mapping relationship and the convergence threshold If the change in the first adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism adjusts the jet angle according to the change of the first adjustment angle Make adjustments;

[0036] The jet angle and the second rotation angle Substitute the change of the second adjustment angle calculated in the second mapping relationship and the convergence threshold If the change in the second adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism adjusts the jet angle according to the change of the second adjustment angle Make adjustments;

[0037] The jet angle 、 Adjust alternately. When the continuous count of real-time times m is equal to n, stop calibration. If the real-time times m do not count, re-adjust the jet angle. 、 Make adjustments.

[0038] According to one embodiment of the present invention, the first adjustment angle is the front and rear pitch angle of the water jet. The second adjustment angle is the left and right rotation angle of the water jet .

[0039] According to one embodiment of the present invention, the first adjustment angle is the left-right rotation angle of the water jet. The second adjustment angle is the front and rear pitch angle of the water jet .

[0040] The present invention provides a water jet machining verticality calibration device, comprising:

[0041] Angle adjustment mechanism, and

[0042] A water-guided laser processing head, the water-guided laser processing head is mounted on the angle adjustment mechanism and is used to eject a water jet to cut a workpiece placed on the work platform;

[0043] The first camera and the second camera are installed at an angle Setting for visually detecting the jet angle of the water jet;

[0044] A host computer, wherein the first camera and the second camera are communicatively connected to the host computer, and the host computer is used to receive image data from the first camera and the second camera and execute a water jet verticality calibration method;

[0045] The angle adjustment mechanism calibrates the jet angle of the water jet according to the calculation result of the host computer.

[0046] According to one embodiment of the present invention, the angle adjustment mechanism is capable of adjusting the front-to-back pitch angle and the left-to-right rotation angle of the water-guided laser machining head.

[0047] Other features and advantages of the present invention will be described in the following description, and in part will become apparent from the description, or understood by practicing the present invention. The purposes and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings.

[0048] 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

[0049] The present invention will be further described below with reference to the accompanying drawings and examples.

[0050] Figure 1 It is a flow chart of the water jet machining verticality calibration method of the present invention.

[0051] Figure 2 1 is a schematic top view of the first camera and the second camera of the present invention.

[0052] Figure 3 It is a schematic diagram of an ideal operation scenario and a non-ideal operation scenario of the present invention.

[0053] Figure 4 is a schematic diagram of a calibration block image captured by the first camera of the present invention.

[0054] Figure 5 is a schematic diagram of a calibration block image captured by the second camera of the present invention.

[0055] Figure 6 Schematic diagram of a water jet image captured by the first camera of the present invention.

[0056] Figure 7 It is a structural schematic diagram of the water jet machining verticality calibration device of the present invention.

[0057] Reference numerals: 1. Angle adjustment mechanism; 2. Water-guided laser processing head; 3. First camera; 4. Second camera. DETAILED DESCRIPTION

[0058] The present invention will now be described in further detail with reference to the accompanying drawings, which are simplified schematic diagrams that illustrate the basic structure of the present invention in a schematic manner.

[0059] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply 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 limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0060] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0061] Example 1

[0062] like Figures 1 to 6 As shown, the water jet machining verticality calibration method of this embodiment includes the following steps: S1, calibrating the first rotation angle between the first camera 3 and the working platform , calibrate the second rotation angle between the second camera 4 and the work platform , the first camera 3 and the second camera 4 are at an angle set up.

[0063] S2. Calibrate the first mapping relationship between the change in the detection angle of the water jet by the first camera 3 and the change in the first adjustment angle of the water jet, and calibrate the second mapping relationship between the change in the detection angle of the water jet by the second camera 4 and the change in the second adjustment angle of the water jet.

[0064] S3. The first camera 3 obtains the jet angle of the water jet , combined with the first rotation angle ,Will Substitute the first mapping relationship to obtain the variation of the first adjustment angle, and the angle adjustment mechanism 1 adjusts the jet angle according to the variation of the first adjustment angle. Calibrate so that the jet angle In the image captured by the first camera 3, state.

[0065] S4. The second camera 4 obtains the jet angle of the water jet , combined with the second rotation angle ,Will Substitute the second mapping relationship to obtain the variation of the second adjustment angle, and the angle adjustment mechanism 1 adjusts the jet angle according to the variation of the second adjustment angle. Calibrate so that the jet angle In the image captured by the second camera 4, state.

[0066] S5, repeat steps S3-S4 until the change in the first adjustment angle and the change in the second adjustment angle are both less than the convergence threshold , calibration is completed.

[0067] It should be noted that the verticality of water jet machining in this embodiment refers to the following: when machining a workpiece, the axis of the water jet (i.e., the machining direction) is perpendicular to the workpiece surface. When the workpiece surface and the work platform remain parallel, the machining direction is also perpendicular to the work platform. The purpose of this calibration method is to ensure that the water jet machining direction is perpendicular to the workpiece surface during machining. This calibration method is not limited to vertical water jet machining scenarios and can also be applied to other scenarios requiring vertical machining.

[0068] In this embodiment, the water jet is ejected by a water-guided laser processing head 2, which is mounted on a crossbeam of the frame. The left end of the crossbeam is mounted on a column, and the right end of the crossbeam is mounted on another column. For example, the first camera 3 is mounted on one column, and the second camera 4 is mounted on another column. The shooting direction of the first camera 3 and the second camera 4 are both toward the water jet. Of course, in other embodiments, the installation positions of the first camera 3 and the second camera 4 can be changed, and this is not limited here. The first camera 3 and the second camera 4 are at an angle. In this embodiment, the angle between the first camera 3 and the second camera 4 is not limited to 90°. For example, the angle is 70° to 110°. That is, in this embodiment, the relative positions of the first camera 3 and the second camera 4 do not have to be installed at 90°, but can be freely adjusted within a certain angle range.

[0069] In the prior art, the two cameras are typically mounted with the first camera 3 behind the water-guided laser processing head 2 (along the X-axis) and the second camera 4 to the side of the water-guided laser processing head 2 (along the Y-axis), with the two cameras arranged at a 90-degree angle. A disadvantage of this prior art mounting method is that the two cameras occupy critical space behind and to the side of the water-guided laser processing head 2, making it difficult to expand the water-guided laser processing equipment with other functions or components within the limited space. Furthermore, with this mounting method, the water jet angle is adjusted relative to the Z-axis, keeping the water jet axis parallel to the Z-axis. This idealizes workpiece processing applications but does not address scenarios where the workpiece surface is non-parallel to the XY plane. For example, if the working plane is non-parallel to the XY plane due to fixture installation or other reasons, the workpiece surface to be processed is non-parallel to the XY plane (i.e., the workpiece surface is non-perpendicular to the Z-axis). Consequently, the jet angle calibrated relative to the Z-axis will not be perpendicular to the workpiece surface, resulting in substandard calibration and poor cutting performance. This embodiment improves the installation position and installation angle of the first camera 3 and the second camera 4, thereby bringing about an innovation in the calibration method for the verticality of the water jet. The calibration method of this embodiment will not be affected by the relative position between the two cameras (the two cameras can be installed on the machine table or on the column, and the installation angle between the two cameras can be adjusted within a certain range). At the same time, it can effectively deal with the situation where the workpiece surface is not perpendicular to the Z axis. In other words, in an ideal working scenario (i.e., the workpiece surface is perpendicular to the Z axis), this method can effectively improve the calibration efficiency and calibration accuracy. In a non-ideal working scenario (i.e., the workpiece surface is not perpendicular to the Z axis), this method will not be affected by the factor that the workpiece surface is not perpendicular to the Z axis, and can ensure the calibration accuracy in non-ideal working scenarios.

[0070] This calibration method consists of three main parts: calibrating the rotation angle relationship between the two cameras and the work platform; calibrating the mapping relationship between the changes in the detection angles of the two cameras and the changes in the first and second adjustment angles; and calibrating the water jet angle based on the calibrated rotation angle relationship and mapping relationship. Each of these three parts is described below.

[0071] Part 1: Calibrate the rotation angle relationship between the two cameras and the work platform. The calibration process between the two cameras and the work platform is similar. Here, the calibration process of the first camera 3 is specifically described.

[0072] Calibrate the first rotation angle between the first camera 3 and the work platform , including: S1.1, placing the calibration block vertically on the work platform and moving it to the field of view of the first camera 3, and the first camera 3 takes the calibration block image. S1.2, performing edge detection on the calibration block in the calibration block image and extracting the left edge line and the right edge line of the calibration block by linear fitting. S1.3, obtaining the center line L1 of the calibration block according to the left edge line and the right edge line of the calibration block, obtaining the center line L2 of the calibration block image in the vertical direction, and the first rotation angle is the direction vector of the center line L1 The angle between it and the midline L2, .

[0073] It should be noted that the calibration block in this embodiment is cylindrical (for simulating a water jet), and the calibration block is placed vertically on the work platform, and then the first camera 3 captures the image of the calibration block. Since the calibration block is relatively long and the camera's shooting range is limited, the calibration block image captured by the first camera 3 only includes a portion of the calibration block (e.g. Figure 4 The left and right edge lines of the calibration block in the calibration block image are extracted using image processing technology, and the center line L2 of the calibration block is obtained based on the left and right edge lines. The center line L2 is the axis of the calibration block and can represent the tilt direction of the calibration block. The direction vector of the calibration block Parallel to the normal line of the work platform. Figure 5 As shown, the second rotation angle , is the direction vector of the center line L1' of the calibration block, and L2 is the center line of the image. The purpose of calibration is to determine the angle of the normal line of the work platform in the camera image for subsequent calibration compensation.

[0074] In order to further improve the accuracy of the rotation angle calibration, the calibration block is moved multiple times along the X and Y directions on the working platform, and the first rotation angle is calculated each time it is moved. , multiple first rotation angles The average of the values ​​is used as the final first rotation angle between the first camera 3 and the work platform. For example, each movement is 1mm in the X direction and 1mm in the Y direction. When each movement is made, it is necessary to ensure that the calibration block is within the field of view of the first camera 3. In this way, the first camera 3 can capture multiple calibration block images and calculate multiple first rotation angles. , take multiple first rotation angles The mean of the values ​​is taken as the final calibrated first rotation angle. In other embodiments, multiple coordinate points can be extracted from the image and fitted into a straight line, and the rotation angle is calculated using the straight line and the direction vector of the calibration block. The benefits of calculating the mean of the rotation angle by multiple moves are: (1) A single measurement may cause deviations in the results due to factors such as image distortion, edge detection errors, and changes in illumination. Multiple measurements can improve the accuracy, stability, and reliability of the calibration results and reduce random errors. (2) Multiple movement measurements can ensure the coordinate system direction of the work platform, avoid contingency, and ensure that the calibrated rotation angle can accurately represent the relative rotation angle between the work platform and the camera.

[0075] Part 2: Calibrate the mapping relationship between the detection angle change of the two cameras and the change of the first adjustment angle and the change of the second adjustment angle. The calibration process of the first camera 3 and the second camera 4 is similar.

[0076] Calibrate the first mapping relationship between the change in the detection angle of the water jet by the first camera 3 and the change in the first adjustment angle of the water jet, including: S2.1, change the first adjustment angle N times, each change angle is the same, and the first camera 3 captures the water jet image after the first adjustment angle is changed N times. S2.2, calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the first adjustment angle is changed for the i-th time, i=1,2,3,...,N; represents the component of the direction vector of the water jet in the X direction when the first adjustment angle is changed for the i-th time, The Y-direction component of the direction vector of the water jet when the first adjustment angle is changed for the i-th time. S2.3. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the first adjustment angle is changed for the i+1th time, Indicates the water jet direction angle when the first adjustment angle is changed for the i-th time, and the angle change A linear fit is performed with the variation of the first adjustment angle to obtain a first mapping relationship between the variation of the detection angle of the first camera 3 and the variation of the first adjustment angle.

[0077] Calibrate the second mapping relationship between the change in the detection angle of the water jet by the second camera 4 and the change in the second adjustment angle of the water jet, including: S2.4, change the second adjustment angle N times, each change angle being the same, and the second camera 4 captures the water jet image after the second adjustment angle is changed N times. S2.5, calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the second adjustment angle is changed for the jth time, j=1,2,3,...,N; It represents the component of the direction vector of the water jet in the X direction when the second adjustment angle is changed for the jth time, The component of the direction vector of the water jet in the Y direction when the second adjustment angle is changed for the jth time. S2.6. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the second adjustment angle is changed for the j+1th time, Indicates the water jet direction angle when the second adjustment angle is changed for the jth time, and the angle change A linear fit is performed with the variation of the second adjustment angle to obtain a second mapping relationship between the variation of the detection angle of the second camera 4 and the variation of the second adjustment angle.

[0078] In this embodiment, the first adjustment angle is the front and rear pitch angle of the water jet. The second adjustment angle is the left and right rotation angle of the water jet Of course, in other embodiments, the first adjustment angle can also be the left and right rotation angle of the water jet. The second adjustment angle is the front and rear pitch angle of the water jet That is to say, the second part of the calibration process is to calibrate the camera's detection angle change of the water jet and the front and rear pitch angles. The change in the amount of rotation, the left and right rotation angle The mapping relationship between the changes in the amount of , one camera corresponds to one mapping relationship.

[0079] Calibrate the detection angle change and front and rear pitch angle of the first camera 3 When the mapping relationship of the change in the amount of the water jet is The angle of the water-guided laser processing head 2 can be changed by controlling the angle adjustment mechanism 1. For example, the front and rear pitch angle Change 0.1° each time, change N times in total, record all the front and rear pitch angles 、 ,..., Each time the pitch angle changes The first camera 3 takes a water jet image and calculates the water jet direction angle in the image, thereby obtaining multiple water jet direction angles. 、 ,..., Calculate the angle change of the water jet direction angle 、 ,..., , the linear fitting form is, for example: , according to this equation, we can solve (i.e., mapping relationship), represents the detection angle change of the first camera 3, Indicates the change in the front and rear pitch angles, 、 are all constants.

[0080] Calibrate the detection angle change and left and right rotation angle of the second camera 4 When the mapping relationship is Each change is 0.1°, and a total of N changes are made, and all left and right rotation angles are recorded. 、 ,..., The second camera 4 takes N water jet images and calculates the water jet direction angle, and then calculates the angle change of the water jet direction angle 、 ,..., , and then perform a linear fit , solve for , represents the detection angle change of the first camera 3, Indicates the change in the front and rear pitch angles, 、 are all constants.

[0081] Through the calibration of the first and second parts, the calibration will not be restricted by the installation angle of the two cameras, nor will it be restricted by whether the workpiece surface is perpendicular to the Z axis. In actual application, this method can be applied to more operating scenarios and is also beneficial to improving the calibration accuracy of the processing verticality, thereby improving the subsequent cutting accuracy of the workpiece.

[0082] Part 3: According to the calibration results of Part 1 and Part 2, the jet angle of the water jet is adjusted. Step S3 specifically includes: Substitute the first mapping relationship to obtain the variation of the first adjustment angle, and the angle adjustment mechanism 1 adjusts the direction of the water jet according to the variation of the first adjustment angle so that the jet angle In the image captured by the first camera 3, State (that is, at this time in the image captured by the first camera 3, the jet direction is perpendicular to the working platform). Step S4 specifically includes: Substitute the second mapping relationship to obtain the variation of the second adjustment angle, and the angle adjustment mechanism 1 adjusts the jet angle according to the variation of the second adjustment angle. Calibrate so that the jet angle In the image captured by the second camera 4, state (that is, in the image taken by the second camera 4 at this time, the jet direction is perpendicular to the working platform).

[0083] Specifically, adjust the front and rear pitch angles When the first camera 3 captures the water jet image and calculates the current jet angle of the water jet (Jet Angle is calculated in the same way as the rotation angle), Substitute the mapping relationship in The current change in the front and rear pitch angle can be obtained by , then the angle adjustment mechanism 1 is adjusted according to the change Adjust the angle of the water-guided laser processing head 2. Then, adjust the left and right rotation angles. The second camera 4 captures the water jet image and calculates the current jet angle of the water jet (Jet Angle is calculated in the same way as the rotation angle), Substitute the mapping relationship of The current left and right rotation angle changes can be obtained by , and then the adjustment mechanism is dispatched according to the change The angle of the water-guided laser processing head 2 is adjusted.

[0084] It should be noted that since the orientations of the first camera 3 and the second camera 4 are not necessarily parallel to the XY direction, when the position of the water jet in the first camera 3 is adjusted, the position of the water jet in the second camera 4 may change. There is a coupling relationship between the two cameras, so the front and rear pitch angles need to be adjusted. , left and right rotation angle Repeated adjustments are made to make the jet angle of the water jet approach the ideal value in the two cameras. Based on this, this embodiment sets the convergence threshold The adjustment process specifically includes: setting the change amount of the first adjustment angle and the change amount of the second adjustment angle to be continuously less than the convergence threshold The number threshold n is set, and the initial value of the real-time number m is set to 0. and the first rotation angle Substitute the change of the first adjustment angle calculated in the first mapping relationship and the convergence threshold If the change in the first adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism 1 adjusts the jet angle according to the change in the first adjustment angle Adjust the jet angle and the second rotation angle Substitute the change of the second adjustment angle calculated in the second mapping relationship and the convergence threshold If the change in the second adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism 1 adjusts the jet angle according to the change in the second adjustment angle Make adjustments. Jet Angle 、 Adjust alternately. When the continuous count of real-time times m is equal to n, stop calibration. If the real-time times m do not count, re-adjust the jet angle. 、 Make adjustments.

[0085] Assume n=2, for example, the calculated and For comparison, assuming that Less than , then m=1; then the calculated and For comparison, assuming that Less than , then m=2, at this time m=n, you can stop calibration. For example, the calculated and For comparison, assuming that Less than , then m=1; then the calculated and For comparison, assuming that Not less than , then m=1, at this time, you need to clear m and start again and In this comparison process, whether the change in the adjustment angle is less than , the jet angle is adjusted according to the calculated change value. 、 and The comparisons are performed alternately, and the angle adjustments are also performed alternately.

[0086] The calibration method of this embodiment calibrates the rotation angle between the two cameras and the work platform, calibrates the mapping relationship between the camera's detection angle change and the front and rear pitch angle and left and right rotation angle, and then uses the calibration results to calibrate the water jet angle. This can achieve the following benefits:

[0087] (1) By calibrating the rotation angle between the camera and the working platform, and the mapping relationship between the camera detection angle change and the adjustment angle change, and then using the calibration results to adjust the jet angle, on the one hand, the calibration efficiency and calibration accuracy of the verticality of the water jet processing can be improved. On the other hand, the calibration result will not be affected by the tilt of the working platform itself (that is, the workpiece surface is not perpendicular to the Z axis), which can further improve the calibration accuracy of the verticality of the water jet relative to the workpiece surface during processing, which is beneficial to improving the cutting accuracy and cutting quality.

[0088] (2) There are relatively few restrictions on the installation position and installation angle of the first camera 3 and the second camera 4, and they will not occupy the key space behind and on the side of the water-guided laser processing head 2. The water jet angle during the processing process can also be detected in real time, abnormalities can be discovered in time, material waste can be reduced, and the defective rate of products can be reduced.

[0089] Example 2

[0090] like Figure 7 As shown, the present invention also provides a water jet processing verticality calibration device, comprising: an angle adjustment mechanism 1, a water-guided laser processing head 2, a first camera 3, a second camera 4 and a host computer, the water-guided laser processing head 2 is installed on the angle adjustment mechanism 1, and the water-guided laser processing head 2 is used to spray water jets to cut the workpiece placed on the working platform; the installation angles of the first camera 3 and the second camera 4 are at an angle Setting, for visual detection of the jet angle of the water jet; the first camera 3 and the second camera 4 are communicatively connected to the host computer, and the host computer is used to receive image data from the first camera 3 and the second camera 4 and execute the water jet verticality calibration method; the angle adjustment mechanism 1 calibrates the jet angle of the water jet according to the calculation results of the host computer.

[0091] The angle adjustment mechanism 1 can adjust the front-to-back pitch angle and the left-to-right rotation angle of the water-guided laser processing head 2. For example, the angle adjustment mechanism 1 is a two-dimensional angular displacement stage.

[0092] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0093] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical spirit of this invention. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for calibrating verticality of water jet machining, characterized in that: The following steps are involved: S1. Calibrate the first rotation angle between the first camera (3) and the working platform , calibrate the second rotation angle between the second camera (4) and the work platform , the first camera (3) and the second camera (4) are at an angle set up; S2, calibrating a first mapping relationship between a change in the detection angle of the water jet by the first camera (3) and a change in a first adjustment angle of the water jet, and calibrating a second mapping relationship between a change in the detection angle of the water jet by the second camera (4) and a change in a second adjustment angle of the water jet; Calibrating a first mapping relationship between a change in the detection angle of the water jet by the first camera (3) and a change in the first adjustment angle of the water jet, comprising: S2.1, changing the first adjustment angle N times, with the angle changed each time being the same, and the first camera (3) capturing images of the water jet after the first adjustment angle is changed N times; S2.

2. Calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the first adjustment angle is changed for the i-th time, i=1,2,3,...,N; represents the component of the direction vector of the water jet in the X direction when the first adjustment angle is changed for the i-th time, represents the component of the direction vector of the water jet in the Y direction when the first adjustment angle is changed for the i-th time; S2.

3. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the first adjustment angle is changed for the i+1th time, represents the water jet direction angle when the first adjustment angle is changed for the i-th time, and the angle change Performing linear fitting with the variation of the first adjustment angle to obtain a first mapping relationship between the variation of the detection angle of the first camera (3) and the variation of the first adjustment angle; Calibrating a second mapping relationship between a change in the detection angle of the water jet by the second camera (4) and a change in the second adjustment angle of the water jet, comprising: S2.4, changing the second adjustment angle N times, with the angle changed each time being the same, and the second camera (4) capturing images of the water jet after the second adjustment angle is changed N times; S2.

5. Calculate the water jet direction angle in the water jet image , represents the direction vector of the water jet when the second adjustment angle is changed for the jth time, j=1,2,3,...,N; It represents the component of the direction vector of the water jet in the X direction when the second adjustment angle is changed for the jth time, represents the component of the direction vector of the water jet in the Y direction when the second adjustment angle is changed for the jth time; S2.

6. Calculate the angle change of the water jet direction angle , represents the water jet direction angle when the second adjustment angle is changed for the j+1th time, represents the water jet direction angle when the second adjustment angle is changed for the jth time, and the angle change Performing linear fitting with the variation of the second adjustment angle to obtain a second mapping relationship between the variation of the detection angle of the second camera (4) and the variation of the second adjustment angle; S3. The first camera (3) obtains the jet angle of the water jet , combined with the first rotation angle ,Will Substituting the first mapping relationship to obtain the variation of the first adjustment angle, the angle adjustment mechanism (1) adjusts the jet angle according to the variation of the first adjustment angle. Calibrate so that the jet angle In the image captured by the first camera (3) state; S4. The second camera (4) obtains the jet angle of the water jet , combined with the second rotation angle ,Will Substitute the second mapping relationship to obtain the variation of the second adjustment angle, and the angle adjustment mechanism (1) adjusts the jet angle according to the variation of the second adjustment angle. Calibrate so that the jet angle In the image captured by the second camera (4) state; S5, repeat steps S3-S4 until the change in the first adjustment angle and the change in the second adjustment angle are both less than the convergence threshold , calibration is completed.

2. The water jet machining verticality calibration method according to claim 1, characterized in that: Calibrate the first rotation angle between the first camera (3) and the working platform ,include: S1.1, placing the calibration block vertically on the working platform and moving it into the field of view of the first camera (3), and the first camera (3) captures an image of the calibration block; S1.2, performing edge detection on the calibration block in the calibration block image and extracting the left edge line and the right edge line of the calibration block by straight line fitting; S1.3, according to the left edge line and the right edge line of the calibration block, obtain the center line L1 of the calibration block, obtain the center line L2 of the calibration block image in the vertical direction, the first rotation angle is the direction vector of the center line L1 The angle between it and the midline L2, .

3. The water jet machining verticality calibration method according to claim 2, characterized in that: Calibrate the first rotation angle between the first camera (3) and the working platform , also includes: S1.

4. Move the calibration block multiple times along the X and Y directions on the work platform, and calculate the first rotation angle each time it moves. , multiple first rotation angles The mean of is taken as the final first rotation angle between the first camera (3) and the working platform.

4. The water jet machining verticality calibration method according to claim 1, characterized in that: Step S5 specifically includes: Set the change of the first adjustment angle and the change of the second adjustment angle to be continuously less than the convergence threshold The number threshold n is set, and the initial value of the real-time number m is set to 0; The jet angle and the first rotation angle Substitute the change of the first adjustment angle calculated in the first mapping relationship and the convergence threshold If the change in the first adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism (1) adjusts the jet angle according to the change of the first adjustment angle Make adjustments; The jet angle and the second rotation angle Substitute the change of the second adjustment angle calculated in the second mapping relationship and the convergence threshold If the change in the second adjustment angle is less than the convergence threshold , then record the real-time number m=m+1, otherwise m is not counted; the angle adjustment mechanism (1) adjusts the jet angle according to the change of the second adjustment angle Make adjustments; The jet angle 、 Adjust alternately. When the continuous count of real-time times m is equal to n, stop calibration. If the real-time times m do not count, re-adjust the jet angle. 、 Make adjustments.

5. The water jet machining verticality calibration method according to claim 1, characterized in that: The first adjustment angle is the front and rear pitch angle of the water jet The second adjustment angle is the left and right rotation angle of the water jet .

6. The water jet machining verticality calibration method according to claim 1, characterized in that: The first adjustment angle is the left and right rotation angle of the water jet The second adjustment angle is the front and rear pitch angle of the water jet .

7. A water jet machining verticality calibration device, characterized in that: include: An angle adjustment mechanism (1), and a water-conducting laser processing head (2), the water-conducting laser processing head (2) being mounted on the angle adjustment mechanism (1), the water-conducting laser processing head (2) being used to eject a water jet to cut a workpiece placed on the working platform; The first camera (3) and the second camera (4) are installed at an angle of Setting for visually detecting the jet angle of the water jet; A host computer, wherein the first camera (3) and the second camera (4) are communicatively connected to the host computer, and the host computer is used to receive image data from the first camera (3) and the second camera (4) and execute the water jet machining verticality calibration method according to any one of claims 1 to 6; The angle adjustment mechanism (1) calibrates the jet angle of the water jet according to the calculation result of the host computer.

8. The water jet machining verticality calibration device according to claim 7, characterized in that: The angle adjustment mechanism (1) is capable of adjusting the front-to-back pitch angle and the left-to-right rotation angle of the water-guided laser processing head (2).

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