An inkjet robot system and an inkjet control method

Abstract

The application discloses a code spraying robot system and a code spraying control method, and comprises an industrial robot, a robot controller, a visual detection device, a spraying device and a host computer. The visual detection device is used for acquiring image information of a steel coil end face. The host computer is used for obtaining code spraying font specifications and code spraying track coordinates according to the image information of the steel coil end face. The robot controller is used for sequentially calling corresponding characters to control the industrial robot and the spraying device to perform code spraying work according to code spraying content, the code spraying font specifications and the code spraying track coordinates. The technical scheme can intelligently perform code spraying work on steel coils with different specifications, sizes and uncertain positions.

Description

Technical Field

[0001] This invention belongs to the field of intelligent control technology, specifically relating to a coding robot system and a coding control method. Background Technology

[0002] Due to the special status of the steel industry in my country's manufacturing sector, optimizing and adjusting industrial processes is a key factor in maintaining the competitiveness of steel enterprises. Steel coils, as an indispensable basic product of the steel industry, require specific information such as coil ID, alloy number, coil weight, and production date for online inspection, quality tracking, and permanent quality traceability. Therefore, it is necessary to print relevant information onto the surface of the coils for enterprise management. Traditional manual spraying methods are inaccurate and inefficient, and most steel mills operate in high-temperature environments. Therefore, enterprises have begun to introduce machines to replace manual spraying. After several years of development, robotic automatic inkjet coding systems have been implemented and put into use, but they are mainly based on dot-matrix spraying. Dot-matrix inkjet coding robots solve the problems of high-temperature spraying and low efficiency of traditional spraying methods, but their spraying devices are prone to clogging, have a high failure rate, and the printed character size is not adjustable. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a coding robot system and coding control method that can perform intelligent coding operations on steel coils of different specifications, sizes and uncertain positions.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A coding robot system includes: an industrial robot, a robot controller, a vision inspection device, a spraying device, and a host computer;

[0006] The system includes a vision inspection device for acquiring image information of the steel coil end face; a host computer for obtaining the printing font specifications and coding trajectory coordinates based on the image information of the steel coil end face; and a robot controller for sequentially calling the corresponding characters to control the industrial robot and spraying device to perform the printing operation based on the printing content, printing font specifications, and coding trajectory coordinates.

[0007] As a preferred method, the host computer converts the image of the steel coil end face into point cloud data, uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of the center point of the steel coil end face; uses the steel coil diameter to calculate the character size scaling parameters to determine the printing font specifications; and uses a character angle offset algorithm to obtain the coordinates of the inkjet printing trajectory based on the position of the center point of the steel coil end face.

[0008] As a preferred option, the host computer uses an adjustable character size algorithm to automatically enlarge or reduce the character size proportionally based on the detected diameter of the steel coil in both linear inkjet printing mode and arc inkjet printing mode around the center point of the steel coil end face, thereby determining the printing font specifications.

[0009] As a preferred method, the host computer obtains the coordinates of the inkjet printing trajectory based on the position of the center point of the steel coil end face using a character angle offset algorithm.

[0010] The present invention also provides a coding control method, comprising:

[0011] Step S1: Obtain image information of the end face of the steel coil using a visual inspection device;

[0012] Step S2: The host computer obtains the printing font specifications and inkjet trajectory coordinates based on the image information of the steel coil end face;

[0013] Step S3: The robot controller calls the corresponding characters in sequence according to the printing content, printing font specifications and inkjet trajectory coordinates to control the industrial robot and spraying device to perform the printing operation.

[0014] Preferably, in step S2, the host computer converts the image of the steel coil end face into point cloud data, uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of the center point of the steel coil end face; calculates the character size scaling parameters based on the steel coil diameter to determine the printing font specifications; and obtains the inkjet printing trajectory coordinates based on the position of the center point of the steel coil end face using a character angle offset algorithm.

[0015] Preferably, in step S2, the character size is automatically enlarged or reduced proportionally according to the detected diameter of the steel coil in both linear inkjet printing mode and arc inkjet printing mode around the center point of the steel coil end face, by using an adjustable character size algorithm to determine the inkjet font specifications.

[0016] Preferably, in step S2, the coordinates of the inkjet printing trajectory are obtained by using a character angle offset algorithm based on the position of the center point of the steel coil end face.

[0017] By combining vision technology with robot control technology for inkjet printing on steel coil ends, robots gain environmental awareness and can perform intelligent inkjet printing on steel coils of varying specifications, sizes, and uncertain locations. This improves work efficiency, meets the intelligent needs of modern industrial production, and also reduces the labor intensity of workers and the production costs for enterprises. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the inkjet coding robot system according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of a coding robot.

[0021] Figure 3 This is a schematic diagram of the end effector of a coding robot.

[0022] Figure 4 This is a schematic diagram of a spraying device.

[0023] Figure 5 This is a flowchart of the inkjet coding robot system. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Example 1:

[0027] like Figure 1 , 2 As shown in Figures 3 and 4, this embodiment of the invention provides a coding robot system for marking and coding steel coils on a steel coil production line. The coding robot system includes: an industrial robot 1, a robot controller 6, a vision inspection device 2, a spraying device, and a host computer 8. The industrial robot 1 is installed on the production line.

[0028] The visual inspection device 2 is a depth camera, fixed to the end effector of the industrial robot 1. The visual inspection device 2 is used to acquire image information of the steel coil end face. Through camera calibration and hand-eye calibration (eye on hand), the visual inspection device 2 obtains the transformation relationship between the camera coordinate system and the end effector coordinate system of the industrial robot 1, thus obtaining the relationship between the steel coil coordinate position and the industrial robot coordinate position. Further, using the hand-eye matrix, based on the coordinates of the target object observed by the camera in the camera coordinate system, the coordinates of the steel coil end face in the industrial robot coordinate system are calculated. Assuming the hand-eye matrix is ​​X, and the coordinates of the target object in the camera coordinate system are [X...], the visual inspection device 2 is used to acquire image information of the steel coil end face. c ,Y c Z c ,1] T The target object's coordinates in the industrial robot coordinate system are [X... b ,Y b Z b ,1] T The calculation formula is:

[0029]

[0030] Where R is a 3×3 rotation matrix; T is a 3×1 translation matrix.

[0031] In one embodiment of the present invention, the host computer 8 obtains the printing font specifications and inkjet trajectory coordinates based on the image information of the steel coil end face. Specifically, the host computer 8 converts the steel coil end face image into point cloud data, uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of its center point; it calculates the character size scaling parameters based on the steel coil diameter to determine the printing font specifications; and it obtains the inkjet trajectory coordinates based on the position of the center point of the steel coil end face using a character angle offset algorithm.

[0032] Furthermore, the font scaling parameters multiplex and multipley are determined based on the steel coil diameter, and the calculation method is as follows:

[0033] Depend on

[0034] We can obtain:

[0035] Where D is the preset reference diameter of the steel coil, corresponding to the reference size of the printed font; D1 detects the diameter of the steel coil; multiplex is the font scaling parameter in the x-direction; multipley is the font scaling parameter in the y-direction.

[0036] The character library is built upon the RAPID language. It contains 26 uppercase letters, 26 lowercase letters, ten Arabic numerals (0-9), and a "-" character, totaling 63 characters. This embodiment of the invention employs an adjustable character size algorithm, automatically scaling the character size proportionally based on the detected steel coil diameter. The specific adjustable character size algorithm is as follows:

[0037] Let each character trajectory occupy a matrix, and each point on the character trajectory correspond to a coordinate on the matrix. After determining the baseline size of the character, a scaling parameter is multiplied by the baseline coordinates. Following the principle of similar triangles, adjusting the scaling parameter changes the corner coordinates of the character, thus altering the character size. Let the width of the baseline character be d0, and the height be h0. The actual printed character width d = d0 × multiplex, and the actual printed character height h = h0 × multipley.

[0038] In linear inkjet printing mode, the starting point of character printing is offset only in one coordinate axis direction, that is, the character offset angle angle0 is set to 0. The offset formula between characters in this mode is as follows:

[0039] drift = d0 × multiplex + L

[0040] Where drift is the offset between characters; L is the font spacing.

[0041] In the arc-shaped inkjet printing mode around the center point of the steel coil end face, the character inkjet starting point is offset in both the x and y directions, meaning the character offset angle angle0 is not 0. The formula for the character inkjet starting point offset in this mode is as follows:

[0042] x-direction offset: driftx = (d + L) × cos[-(n-1) × angle0]

[0043] y-direction offset: drifty = (d + L) × sin[-(n-1) × angle0]

[0044] Where angle0 is the initial rotation offset angle of the character, n is the order of the character in the string, driftx is the offset in the x-direction, and drifty is the offset in the y-direction.

[0045] Furthermore, based on the center point position of the steel coil end face, the coordinates of the inkjet printing trajectory can be obtained through a character angle offset algorithm. The principle of the character angle offset algorithm is coordinate rotation. Specifically, after giving the starting point p0 of the first character trajectory, the reference point of subsequent characters can be obtained by coordinate translation and rotation transformation based on the coordinates of p0. Similarly, since the other coordinates on each character are obtained by offsetting the reference point of that character, the other coordinates can also be obtained through translation and rotation transformation. The coordinates of p0 are given by the vision inspection device. The formula is as follows:

[0046] Let p0(x0,y0,z) be defined.

[0047] p n (x n ,y n ,z)

[0048] in,

[0049] x n =[x0×multiplex×cos(angle)]-[y0×multipley×sin(angle)]

[0050] y n =[x0×multiplex×sin(angle)]+[y0×multipley×cos(angle)]

[0051] z is the distance between the end face of the steel coil and the coordinates of the industrial robot; angle is the character rotation angle; the initial value of the character rotation angle is set to angle0, and the rotation angle of the nth character is angle(n) = -n×angle0.

[0052] Furthermore, the spraying device includes an air compressor, a solenoid valve 3, an oil and gas tank 7, and a nozzle 4. The nozzle 4 is installed at the end of the industrial robot 1, and its start and stop are controlled by the solenoid valve 3. The oil and gas tank 7 provides a constant-pressure air source and a constant-pressure oil supply to the spraying device. The robot controller 6 controls the movement trajectory of the industrial robot and the start and stop of the spraying device. Based on the printing content, font specifications, and code trajectory coordinates, the robot controller 6 sequentially calls the corresponding characters to control the industrial robot and the spraying device to perform the printing operation.

[0053] The spraying device prints the specifications of the steel coil onto the end face of the steel coil using a paint spraying method. It can print the parameters of the steel coil 5 for steel coils with a temperature range of 500 degrees Celsius and below. The printed content includes: steel coil model, steel coil weight and production date.

[0054] like Figure 5 As shown, the workflow of the inkjet coding robot system in this embodiment of the invention includes:

[0055] S1: Before starting the inkjet robot system, the vision inspection device must first be calibrated with camera and hand-eye calibration to obtain the transformation relationship between camera coordinates and industrial robot end coordinate system, that is, the transformation relationship between hand-eye matrix and steel coil position coordinates and camera coordinate system, and obtain the transformation relationship between steel coil position coordinates and robot coordinates.

[0056] S2: After the calibration work is completed, the steel coil 5 is transported to the coding robot's work area by the conveyor. When the steel coil is detected to be in place, the conveyor stops running.

[0057] S3: The inkjet coding robot system starts. The industrial robot moves to the image acquisition point, triggering the vision inspection device to acquire signals. The vision inspection device acquires image information of the steel coil end face and generates point cloud data.

[0058] S4: The host computer processes the point cloud data, calculates the diameter of the steel coil, the coordinates of the center point of the steel coil end face in the camera coordinate system, and then calculates the coordinates of the center point of the steel coil end face in the robot coordinate system.

[0059] S5: The host computer 8 retrieves the steel coil specifications, production date, and quality information from the system database and generates the corresponding printing content; it calculates the character scaling parameters and character offset angles based on the steel coil diameter to determine the printing character size; and it calculates the printing start point coordinates based on the center point coordinates of the steel coil end face.

[0060] S6: Robot controller 6 calls the corresponding characters in sequence to start the printing operation according to the printing content, printing character size and starting point coordinates. After printing is completed, the robot returns to the waiting point to wait for the next work signal.

[0061] This invention integrates visual inspection technology with robot control technology to form a vision-guided robotic inkjet printing system, solving the problem that traditional inkjet printing robots have limited working scenarios and cannot adapt to changing work environments. This invention also constructs a character library with adjustable font sizes based on the RAPID language. The font size can be determined by modifying parameters according to actual working conditions, thus requiring only the character library to meet the requirements of all font sizes, expanding the font range while reducing the character library capacity. In summary, this invention improves the intelligence level of inkjet printing robots, increases inkjet printing efficiency, and reduces enterprise production costs and worker labor intensity.

[0062] Example 2:

[0063] This invention also provides a coding control method, including:

[0064] Step S1: Obtain image information of the end face of the steel coil using a visual inspection device;

[0065] Step S2: The host computer 8 obtains the printing font specifications and inkjet trajectory coordinates based on the image information of the steel coil end face;

[0066] Step S3: The robot controller 6 calls the corresponding characters in sequence according to the printing content, printing font specifications and inkjet trajectory coordinates to control the industrial robot and spraying device to perform the printing operation.

[0067] In one embodiment of the present invention, in step S2, the host computer 8 converts the image of the steel coil end face into point cloud data, uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of the center point of the steel coil end face; calculates the character size scaling parameters through the steel coil diameter to determine the inkjet font specifications; and obtains the inkjet trajectory coordinates through a character angle offset algorithm based on the position of the center point of the steel coil end face.

[0068] As one embodiment of the present invention, in step S2, the character size is automatically enlarged or reduced proportionally according to the detected diameter of the steel coil in both linear inkjet printing mode and arc inkjet printing mode around the center point of the steel coil end face, by using an adjustable character size algorithm to determine the inkjet font specifications.

[0069] In one embodiment of the present invention, in step S2, the coordinates of the inkjet printing trajectory are obtained by using a character angle offset algorithm based on the position of the center point of the steel coil end face.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A coding robot system, characterized in that, include: Industrial robots, robot controllers, vision inspection devices, spraying equipment, and host computers; among them, A vision inspection device is used to acquire image information of the end face of the steel coil; a host computer is used to obtain the printing font specifications and inkjet trajectory coordinates based on the image information of the end face of the steel coil; a robot controller is used to sequentially call the corresponding characters to control the industrial robot and spraying device to perform the printing operation according to the printing content, printing font specifications and inkjet trajectory coordinates. The host computer converts the image of the steel coil end face into point cloud data, and uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of the center point of the steel coil end face; the character size scaling parameters are calculated from the steel coil end face diameter to determine the printing font specifications; and the inkjet trajectory coordinates are obtained from the position of the center point of the steel coil end face using a character angle offset algorithm. The host computer uses an adjustable character size algorithm to automatically enlarge or reduce the character size proportionally based on the detected diameter of the steel coil end face in both linear inkjet printing mode and arc inkjet printing mode around the center point of the steel coil end face, thereby determining the inkjet font specifications. In linear inkjet printing mode, the starting point of character printing is offset only in one coordinate axis direction, that is, the character offset angle angle0 is set to 0. The offset formula between characters in this mode is as follows: Where drift is the offset between characters; L is the font spacing; d0 is the width of the base character; and multiplex is the font scaling parameter in the x-direction. ; Where D is the preset reference diameter of the steel coil, corresponding to the reference size of the printed font; D1 is the diameter of the detected steel coil; In the arc-shaped inkjet printing mode around the center point of the steel coil end face, the character inkjet starting point is offset in both the x and y directions, meaning the character offset angle angle0 is not 0. The formula for the character inkjet starting point offset in this mode is as follows: x-direction offset: y-direction offset: Where angle0 is the initial rotation offset angle of the character, n is the character's order in the string, driftx is the offset in the x-direction, drifty is the offset in the y-direction, and d is the actual printed character width. .

2. A coding control method based on the coding robot system of claim 1, characterized in that, include: Step S1: Obtain image information of the end face of the steel coil using a visual inspection device; Step S2: The host computer obtains the printing font specifications and inkjet trajectory coordinates based on the image information of the steel coil end face; Step S3: The robot controller calls the corresponding characters in sequence according to the printing content, printing font specifications and inkjet trajectory coordinates to control the industrial robot and spraying device to perform the printing operation. In step S2, the host computer converts the image of the steel coil end face into point cloud data, uses a circular surface fitting algorithm to calculate the diameter of the steel coil end face and the position of the center point of the steel coil end face; the character size scaling parameter is calculated through the diameter of the steel coil end face to determine the printing font specifications; and the inkjet trajectory coordinates are obtained through a character angle offset algorithm based on the position of the center point of the steel coil end face. In step S2, the character size is automatically enlarged or reduced proportionally according to the detected diameter of the steel coil end face in both linear inkjet printing mode and arc inkjet printing mode around the center point of the steel coil end face, by using an adjustable character size algorithm to determine the inkjet font specifications. In step S2, the coordinates of the inkjet printing trajectory are obtained by using a character angle offset algorithm based on the position of the center point of the steel coil end face.

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