A spraying method for the inner wall of a small hole with a large length-diameter ratio

Abstract

The application discloses a spraying method for the inner wall of a small hole with a large length-diameter ratio, which comprises the following steps: step 1, positioning the small hole by calibrating multiple angles of a spray gun according to preset parameters; and step 2, spraying. According to a conventional visual camera calibration method, the calibration of the small hole is completed. The x-axis and y-axis of a camera coordinate system should coincide with the x-axis and y-axis of a robot, respectively. When the relative position of the spray gun and the camera changes, the quick correction can be completed by the following method, and the camera needs to be calibrated again.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automatic spraying, and more particularly to a spraying method for the inner wall of a small hole with a large length-diameter ratio. BACKGROUND

[0002] Although automatic spraying has been widely used in industry, there is currently no technical means for spraying a small hole with a diameter less than 5 mm and a depth exceeding 30 mm. Conventional spraying methods are difficult to explore into a small hole with a large length-diameter ratio for spraying the inner wall thereof due to the size of the spray gun and the atomization method.

[0003] In addition, positioning during small hole spraying is also difficult. 2D vision camera positioning technology has been widely used in automatic production. Before use, the camera must be calibrated, which involves hand-eye calibration, matching of the camera coordinate system and the robot coordinate system, feature learning, origin establishment and other work. In most application scenarios, the positional relationship between the positioning camera and the assembly and gripping tools is relatively fixed. After camera calibration, automatic recognition, positioning, assembly and gripping can be achieved once and for all. However, in some special industries, such as spraying, the spray gun needs to be frequently disassembled and cleaned, and the relative positional relationship between the spray gun and the camera will change frequently. In order to ensure positioning accuracy, the camera position needs to be recalibrated after each change in relative position. The calibration work is tedious and inefficient.

[0004] Therefore, the present application provides a spraying method for the inner wall of a small hole, which solves the problems of rapid positioning of a small hole and spraying the inner wall of a small hole. SUMMARY

[0005] The present application aims to provide a spraying method for the inner wall of a small hole with a large length-diameter ratio, in order to solve the technical problems in the background art.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A spraying method for the inner wall of a small hole with a large length-diameter ratio, comprising the following steps:

[0008] Step 1: calibrate the multiple angles of the spray gun according to preset parameters to achieve positioning of the small hole;

[0009] Step 2: spraying.

[0010] In some embodiments, the calibration of the multiple angles of the spray gun according to preset parameters to achieve positioning of the small hole comprises:

[0011] (1) compile a robot program in the following manner:

[0012] a. establish n points P1, P2, P3,..., Pn for storing spray gun coordinate data;

[0013] b. Establish n points A1, A2, A3…An for storing the spray gun angle data;

[0014] c. Establish n variable points PA10, PA20, PA30…PAn0 for storing the coordinate data of the small hole center;

[0015] d. Establish 2 variables mod_x0, mod_y0;

[0016] (2) Take a picture of the small hole by using the camera, and modify the variables mod_x0, mod_y0 in the robot program to the coordinate values recognized by the camera respectively;

[0017] (3) Adjust the robot posture, so that the spray gun rotates to the required angle around the atomizer axis in the same posture as the small hole center line, modify A1 to the current point posture, and use the same method to obtain A2, A3, …, An multiple spray gun angle points;

[0018] (4) Move the robot, so that the spray gun reaches the small hole center in the A1 posture, and modify P1 to the current point coordinate; use the same method to obtain the coordinates of P2, P3…Pn;

[0019] (5) In the spraying program, assign values to PA10, PA20, PA30…PAn0; the coordinates of PA10 are equal to the coordinates of P1 plus the current small hole coordinate recognized by the camera minus (mod_x0, mod_y0), and the posture is equal to the posture of A1.

[0020] (6) When the spray gun is disassembled and reassembled, only (2), (3), (4) need to be executed to complete the quick calibration of multiple angles of the spray gun.

[0021] In some embodiments, the spraying includes using a preset inclined atomizer matched with the spray gun and installed on the robot to realize the spraying of the inner wall of the small hole; wherein the atomizer is matched with the needle through an atomizing sleeve to realize the inclined atomization of the coating.

[0022] In some embodiments, the atomizing sleeve is a metal tube with an inner diameter of (0.8-2) mm and an outer diameter of (1.5-3) mm; the outlet of the atomizer is in the middle of the needle and the needle outlet, one side of the atomizer outlet is the outlet of the atomizing air; the needle and the atomizing sleeve are coaxially installed, and the head of the needle is exposed from the atomizing sleeve by (0.1-1) mm.

[0023] In some embodiments, the spraying includes:

[0024] After the coating flows out of the needle, it is atomized at the same time and deviated to the other side of the atomizing air outlet;

[0025] The small hole is positioned by a visual system, and the robot inserts the spray gun into the small hole to spray according to the positioning coordinates;

[0026] After the spray gun is inserted into the small hole, the spray gun moves up and down at a certain speed to complete the spraying of the inner wall at different depths of the small hole;

[0027] After spraying in one direction, the spray gun is rotated by a certain angle and re-inserted into the small hole to spray from another angle.

[0028] In some embodiments, after the inner wall of the small hole is sprayed, the spray gun is moved above the small hole opening and kept a certain distance from the small hole opening to spray the opening of the small hole.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] The present application solves the problems of rapid positioning of small holes and spraying of the inner wall of the small hole. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a schematic view of the end structure of the inclined atomizer; DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme of the embodiments of the present application will be described in more detail below in combination with the drawings of the preferred embodiments of the present application. In the drawings, the same or similar reference numerals represent the same or similar components or components having the same or similar functions throughout. The described embodiments are part of the embodiments of the present application, not all of the embodiments. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0033] The embodiments of the present application will be described in detail below in combination with the drawings.

[0034] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0035] In the description of the present application, it needs to be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship of the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0036] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or display that includes a series of steps or units includes not necessarily limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or displays.

[0037] The following will be combined with Figure 1 A spraying method for the inner wall of a large-length-diameter small hole will be described in detail. It is worth noting that the following embodiments are only used to explain the present application and do not constitute a limitation on the present application.

[0038] Embodiment 1:

[0039] Referring to Figure 1 A spraying method for the inner wall of a large-length-diameter small hole, comprising:

[0040] Step 1: According to the preset parameters, the multiple angles of the spray gun are calibrated to realize the positioning of the small hole;

[0041] According to the conventional visual camera calibration method, the calibration of the small hole is completed. The x-axis and y-axis of the camera coordinate system should coincide with the x-axis and y-axis of the robot, respectively. When the relative position of the spray gun and the camera changes, the quick correction can be completed by the following method, and there is no need to read a camera for re-calibration.

[0042] (1) The robot program is compiled in the following way:

[0043] a. Establish n points P1, P2, P3……Pn for storing spray gun coordinate data;

[0044] b. Establish n points A1, A2, A3……An for storing spray gun angle data;

[0045] c. Establish n variable points PA10, PA20, PA30……PAn0 for storing the coordinate data of the center of the small hole opening.

[0046] d. Establish 2 variables mod_x0, mod_y0;

[0047] (2) Use the camera to take a picture of the small hole, and modify the variables mod_x0 and mod_y0 in the robot program to the coordinate values recognized by the camera.

[0048] (3) Adjust the robot pose so that the spray gun is coaxial with the centerline of the small hole and rotates around the atomizer axis to the desired angle. Modify A1 to the current point pose. In order to meet the needs of spraying at multiple angles on the inner wall of the small hole, the spray gun can be rotated through a series of angles to obtain A2, A3, …, An.

[0049] (4) Move the robot so that the spray gun is at A1 pose and reaches the center of the small hole opening, and modify P1 to the current point coordinates. Using the same method, the coordinates of P2, P3, …, Pn can be obtained.

[0050] (5) In the spraying program, assign values to PA10, PA20, PA30, …, PAn0. The coordinates of PA10 are equal to the coordinates of P1, plus the current recognized coordinates of the small hole by the camera, minus (mod_x0, mod_y0), and the pose is equal to the pose of A1.

[0051] (6) When the spray gun is disassembled and reassembled, only steps (2), (3), and (4) need to be performed to complete the rapid calibration of multiple angles of the spray gun. There is no need to recalibrate the camera.

[0052] Step 2: Spraying.

[0053] The present application designs an inclined atomizer which is used with a spray gun (model: HB-02ZW) and installed on a robot, and realizes the spraying of the inner wall of a small hole by combining a syringe pump feeding system and a visual positioning system.

[0054] An inclined atomizer is designed, which realizes the inclined atomization of paint by cooperating with a gun needle 11 through an atomization sleeve 12. The atomization sleeve 12 is a metal pipe with an inner diameter of (0.8-2) mm and an outer diameter of (1.5-3) mm. The outlet of the atomizer 12 is in the middle of the gun needle 11 and the gun needle outlet 18, and one side of the atomizer outlet 12 is the outlet 17 of the atomizing air. The gun needle 11 and the atomization sleeve 12 are coaxially installed, and the head of the gun needle 11 is exposed from the atomization sleeve 12 by about 0.5 mm.

[0055] After the paint flows out of the gun needle, it is atomized at the same time and deviates to the other side of the atomizing air outlet 17.

[0056] A visual system is used to position the small hole, and the robot inserts the spray gun into the small hole for spraying according to the positioning coordinates.

[0057] The flow rate of the paint for small hole spraying is within 0.5 mL / min.

[0058] After the lance is inserted into the hole, it is moved up and down at a certain speed to complete the spraying of the inner wall of the hole at different depths.

[0059] After the spraying of the inner wall of the hole is completed, the lance is moved to above the hole opening and kept at a certain distance from the hole opening to spray the hole opening to make up for the insufficient spraying of the opening caused by the atomizing gas flow.

[0060] After spraying in one direction is completed, the lance is rotated by a certain angle and re-inserted into the hole from another angle to spray. Multiple angles can be sprayed to ensure that the inner wall of the hole is sprayed and the coating film thickness is uniform.

[0061] By controlling the coating flow rate and the moving speed of the lance inside the hole, the thickness of the coating can be controlled.

[0062] At different depths in the hole, the speed of the lance can be flexibly set according to the diameter of the hole at the place and the required coating thickness. That is, different speeds can be set at different depths to make the coating thickness meet the requirements, without being affected by the size change of the hole at different depths.

[0063] The above only describes the preferred embodiments of the present application and is used to limit the present application. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A spraying method for the inner wall of a small orifice with a large aspect ratio, characterized in that, Includes the following steps: Step 1: Calibrate the spray gun at multiple angles according to preset parameters to achieve orifice positioning; Step 2: Spraying; The process of calibrating the spray gun at multiple angles according to preset parameters to achieve pinhole positioning includes: (1) Program the robot as follows: a. Establish n points P1, P2, P3...Pn to store the spray gun coordinate data; b. Establish n points A1, A2, A3...An to store the spray gun angle data; c. Establish n variable points PA10, PA20, PA30...PAn0 to store the coordinate data of the center of the small hole opening; d. Create two variables, mod_x0 and mod_y0; (2) Take pictures of the small hole with a camera, and modify the variables mod_x0 and mod_y0 in the robot program to the coordinate values ​​recognized by the camera; (3) Adjust the robot's posture so that the spray gun rotates around the atomizer axis to the required angle with the center line of the small hole as the axis; modify A1 to the current point posture; use the same method to obtain multiple spray gun angle points A2, A3, ..., An; (4) Move the robot so that the spray gun reaches the center of the small hole in posture A1, and modify P1 to the current point coordinates; use the same method to obtain the coordinates of P2, P3...Pn; (5) In the spraying program, PA10, PA20, PA30...PAn0 are assigned values; the coordinates of PA10 are equal to the coordinates of P1 plus the current aperture coordinates recognized by the camera minus (mod_x0, mod_y0), and the attitude is equal to the attitude of A1. (6) When the spray gun is disassembled and reassembled, you only need to execute (2), (3), and (4) to quickly calibrate multiple angles of the spray gun.

2. The spraying method for the inner wall of a small orifice with a large aspect ratio according to claim 1, characterized in that, The spraying process includes using a pre-set tilting atomizer in conjunction with a spray gun and mounted on a robot to spray the inner wall of a small hole; wherein, the atomizer works with the gun needle through an atomizing sleeve to achieve tilted atomization of the paint.

3. The spraying method for the inner wall of a small orifice with a large aspect ratio according to claim 2, characterized in that, The atomizing sleeve is made of a metal tube with an inner diameter of 0.8-2mm and an outer diameter of 1.5-3mm; the outlet of the atomizer has a needle and a needle outlet in the middle, and the outlet of atomized air is on one side of the atomizer outlet; the needle and the atomizing sleeve are coaxially installed, and the tip of the needle protrudes 0.1-1mm from the atomizing sleeve.

4. The spraying method for the inner wall of a small orifice with a large aspect ratio according to claim 3, characterized in that, The spraying includes: After the paint flows out of the needle, it is atomized and deflected to the other side of the atomizing air outlet. A vision system is used to locate the small holes, and the robot inserts the spray gun into the small holes to spray paint according to the positioning coordinates; After the spray gun is inserted into the small hole, it moves up and down at a certain speed to complete the spraying of the inner wall of the small hole at different depths. After spraying in one direction, rotate the spray gun at a certain angle and re-enter the hole from another angle to spray from multiple angles, ensuring that the inner wall of the hole is sprayed around the perimeter and that the coating thickness is uniform.

5. The spraying method for the inner wall of a small orifice with a large aspect ratio according to claim 3, characterized in that, After the inner wall of the orifice is coated, the spray gun is moved above the orifice opening and kept at a certain distance from the orifice opening to spray the orifice opening.

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