UAV inkjet printing system and method based on projection positioning

Abstract

The present invention discloses a drone-based spray painting system and method based on projection positioning. The system includes a projection device, a drone-based spraying device, and a controller. The projection device projects onto the surface to be sprayed, and a camera captures the projected calibration grid. After control processing, the distance between the drone and the calibration grid is determined, and further, whether the spraying is complete is determined, thereby completing the entire spraying of the surface to be sprayed. This method has a simple system structure and does not require a precision positioning device.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicle (UAV) control, and in particular to a UAV printing system and method based on projection positioning. Background Art

[0002] The current mainstream approach for using drones for spray painting operations is to mount the spraying device on the drone platform, increasing its size and functionality based on the required spraying capacity and payload. However, the drone system and the spraying system it carries are inherently independent. In practice, the integrated use of drone flight control and spraying operations leads to certain coordination issues between the two independent systems during operation, thus limiting the functionality and performance of the aerial spraying system based on the drone platform. Specifically, it manifests itself in the following aspects: 1: The flight positioning requirements and spraying requirements of the UAV are difficult to coordinate and unify, which results in the UAV being unable to adjust its position and attitude according to the requirements of the spraying, thus affecting the spraying effect; 2: Different working conditions of the spraying operation have a great influence on the attitude stability of the UAV. For example, when the UAV starts to spray, its huge reaction force will directly affect the attitude and position of the UAV, destroying the accuracy of the UAV positioning and the spraying angle, etc.; 3: The UAV is close to the wall, its air flow is turbulent and the aerodynamic conditions acting on the UAV platform are complex, which also increases the difficulty of stable control and safe use of general UAVs; 4. If the UAV is to be positioned during the spraying process and the spraying content is determined based on the positioning, another positioning method and corresponding positioning device are required (such as a high-precision gyroscope, or centimeter-level or even millimeter-level high-precision satellite positioning, or a wireless positioning receiver, etc.), which will lead to increased cost and weight.

[0003] Existing inkjet printing technologies and systems are not yet available for directly printing on large surfaces (such as building walls, floors, and the exterior of metal houses). Current methods for painting on walls involve either printing on a large canvas and then affixing the canvas to the surface. Direct painting on large surfaces is not feasible. Summary of the Invention

[0004] In order to overcome the shortcomings and deficiencies of the prior art, the present invention provides a UAV inkjet printing system and method based on projection positioning.

[0005] The present invention adopts the following technical solutions:

[0006] A UAV inkjet printing system based on projection positioning, comprising:

[0007] Projection equipment: used to project positioning markings onto the surface to be sprayed, wherein the positioning markings are grid lines;

[0008] UAV spraying equipment: including a UAV equipped with a camera and spraying equipment, with the surface to be sprayed and the positioning mark within the field of view of the camera;

[0009] Controller: Connected to the camera, drone and spraying equipment respectively, the camera captures the positioning mark of the surface to be sprayed to determine whether the spraying is completed. If the spraying is completed, the distance between the drone and the surface to be sprayed is determined and the drone is adjusted to the next position to be sprayed. Otherwise, the positioning mark image captured by the camera is compared with the target image to control the spraying equipment path to complete the spraying.

[0010] Furthermore, the spraying equipment is connected to the drone via a connecting rod.

[0011] Furthermore, the grid lines are specifically a grid of N rows and M columns, adjacent grids are separated by grid lines, and the intersections of the grid lines are marked with a combination of letters and numbers, specifically:

[0012] Use different letters to indicate horizontal or vertical directions, and use numbers to indicate the number of grids;

[0013] The grid lines are divided into a plurality of grid blocks, and each grid block is marked with a number from 0 to 9.

[0014] Furthermore, the grid lines include a grid of N rows and M columns, requiring a total of N+1 horizontal network lines and M+1 vertical network lines. N+1 horizontal network lines and M+1 vertical grid lines, using a straight line with multiple small patterns of the same interval as network identifiers requires a total of (N+1)+(M+1) different patterns.

[0015] A spraying method for an unmanned aerial vehicle (UAV) spray painting system based on projection positioning, comprising the following steps:

[0016] The projection equipment projects the positioning markings onto the surface to be sprayed;

[0017] The drone rotates, and the camera captures and photographs the positioning mark;

[0018] Determine the distance between the drone and the surface to be sprayed. If the positioning line is incomplete, adjust the drone's position and re-photograph the positioning line. If it is complete, determine whether the current position has been sprayed. If not, obtain the position information based on the current positioning line.

[0019] According to the position information, it is compared with the target image, and the spraying equipment is controlled to spray at that position.

[0020] Furthermore, if the current position has been sprayed, the drone is adjusted to the next position.

[0021] Further, it is determined whether the current position has been sprayed, specifically:

[0022] The controller stores the positioning mark grid image of the sprayed target image. The drone takes a combined image of the entire current sprayed surface and the positioning mark grid. The controller compares the two images to obtain the spraying effect and whether the spraying is completed.

[0023] Furthermore, the controller compares the image captured by the camera with the stored positioning mark grid image, and obtains the distance based on the comparison between the captured image and the positioning mark grid.

[0024] A storage medium having a computer program stored thereon, characterized in that the computer program implements the spraying method when executed by a processing device.

[0025] Beneficial effects of the present invention:

[0026] (1) The present invention adopts a UAV spraying system based on projection positioning. Compared with the system in the prior art that requires a fixed bracket to spray on the facade, the present system can spray in places where support is difficult to implement (such as the exterior walls of buildings, cliffs, etc.).

[0027] (2) The present invention does not require a satellite positioning device or a gyroscope positioning device or other devices with precise positioning, but only requires a camera for positioning (and the camera is often provided by the drone), which is low in cost and simple and convenient to calculate.

[0028] (3) The present invention is highly feasible, the entire system is simple, and each component has a mature product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a workflow diagram of the present invention;

[0030] Figure 2 1 is a schematic diagram of a positioning marking line according to embodiment 1 of the present invention;

[0031] Figure 3 This is a schematic diagram of the positioning marking line of Example 2 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to the embodiments and the accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0033] Example 1

[0034] like Figure 1-Figure 3 As shown, a UAV spray painting system based on projection positioning includes: a projection device, a UAV spraying device and a controller.

[0035] The projection device is used to optically project positioning markings onto the surface to be sprayed, wherein the positioning markings are grid lines.

[0036] UAV spraying equipment: includes a UAV, on which a camera and a spraying equipment are provided, the spraying equipment is connected to the UAV via a connecting rod, and the surface to be sprayed and the positioning mark are within the field of view of the camera.

[0037] Furthermore, the number of cameras can be one or more, and using multiple cameras can achieve more accurate positioning, and the specific position is set according to the situation of the spraying surface.

[0038] Furthermore, the connecting rod is slender and extends out of the drone to prevent the drone and the connecting rod from blocking the positioning mark projected by the projection equipment, which may cause work errors.

[0039] The controller is connected to the camera, drone and spraying equipment respectively. The camera captures the positioning mark of the surface to be sprayed to determine whether the spraying is completed. If the spraying is completed, the distance between the drone and the surface to be sprayed is determined and the drone is adjusted to the next position to be sprayed. Otherwise, the positioning mark image captured by the camera is compared with the target image to control the spraying equipment path to complete the spraying.

[0040] Specifically, the controller can be set in the drone or set separately.

[0041] The grid lines used in this embodiment are specifically a grid of N rows and M columns. Adjacent grids are separated by grid lines, and the intersections of the grid lines are marked with a combination of letters and numbers, specifically:

[0042] Use different letters to indicate horizontal or vertical directions, and use numbers to indicate the number of grids;

[0043] The grid lines are divided into a plurality of grid blocks, and each grid block is marked with a number from 0 to 9.

[0044] like Figure 2 As shown:

[0045] The entire spraying screen is divided into a grid of N rows and M columns, and the grids are separated by grid lines (a total of N+1 horizontal grid lines and M+1 vertical grid lines are required.

[0046] At the intersection of the grid lines, use a set of red letters / numbers like "A1"\"B5" to indicate the horizontal and vertical grid coordinates.

[0047] On the grid lines between the intersections, small numbers from 0 to 9 are marked in sequence at certain intervals to indicate more detailed position divisions within the grid blocks.

[0048] For the alphanumeric marking scheme, the controller uses the letters and numbers on the four corners of each grid in the N*M grid to determine which grid it is in the entire format (and which side is top and which side is bottom), and then uses "1, 2, 3, 4, 5, 6, 7, 8, 9" on the grid lines to perform more detailed positioning within the grid.

[0049] The spraying method based on the above-mentioned spraying system includes the following steps:

[0050] The S1 projection device projects positioning markings onto the surface to be sprayed. The positioning markings are alphanumeric mixed grid lines.

[0051] The camera takes a target image of the entire surface to be sprayed + the positioning mark grid as the initial state image. When the spraying is completed and the spraying effect is evaluated, the camera on the drone takes an image of a certain grid that has been sprayed. By comparing this current image with the initial state image taken before (using image pixel subtraction, etc.), the spraying effect can be judged and further it can be determined which positions need to be supplemented.

[0052] The S2 drone rotates, and the camera captures the positioning mark and takes a photo of the positioning mark.

[0053] S3 uses the positioning lines captured in S2 to determine the distance between the drone and the surface to be sprayed. The positioning lines must be captured completely. The judgment is made based on whether the captured photo captures the four intersection positions of the grid lines. If there are less than four intersection grid lines, the positioning lines are not captured completely and the distance needs to be adjusted and re-photographed.

[0054] If the positioning mark has been completely photographed, it is determined whether the current position has been sprayed. Specifically, the controller compares the combined image of the sprayed surface and the positioning mark grid with the initial state image. If the current position has been sprayed, the drone is adjusted to enter the next position.

[0055] S4 compares the position information with the target image, controls the spraying equipment, and sprays the position.

[0056] Furthermore, the present invention can also be used to determine whether the surface to be sprayed is flat or uneven by photographing the positioning markings through drones. If the surface to be sprayed has large unevenness (exceeding the size of a grid), the positioning marking grid projected onto the surface will be deformed.

[0057] Specifically, because the image projected by the drone is radially divergent, the farther away from the drone's projection system, the larger the projected image (and positioning mark) will be. Based on this property, the drone can determine the distance to the surface to be sprayed.

[0058] Example 2

[0059] The difference between Example 2 and Example 1 is that the positioning grid used in this example is a special pattern of marking lines, specifically:

[0060] The grid lines include a grid of N rows and M columns, requiring a total of N+1 horizontal network lines and M+1 vertical network lines. N+1 horizontal network lines and M+1 vertical grid lines, with multiple small patterns with the same intervals added on a straight line as network identifiers, require a total of (N+1)+(M+1) different patterns.

[0061] like Figure 3 As shown,

[0062] Divide the entire spray painting screen into a grid of N rows and M columns, with grid lines separating the grids (a total of N+1 horizontal grid lines and M+1 vertical grid lines are required)

[0063] N+1 horizontal grid lines and M+1 vertical grid lines are used. Multiple small patterns with equal spacing are added to the straight lines as network markers to facilitate machine recognition by the drone system through the camera. This requires a total of (N+1)+(M+1) different patterns.

[0064] At the intersection of network lines, directional symbols or graphics (such as arrow graphics, etc.) are used to indicate the upward direction, so that the drone system can recognize the machine through the camera.

[0065] The positioning process of the special pattern markings mentioned above is as follows:

[0066] The directional patterns at the intersection of the grid lines are used to determine which side is up and which is down. The boundaries of the grid are determined by identifying the grid lines. The patterns on the four grid lines around the grid are used to determine whether the grid is another grid in the entire format. The position of small patterns on the grid lines is used for more detailed positioning within the grid.

[0067] Example 3

[0068] A storage medium stores a computer program, which, when executed by a processor, implements any one of the above-mentioned spraying method steps.

[0069] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A spraying method for an unmanned aerial vehicle spray painting system, characterized in that: The UAV printing system includes: Projection equipment: used to project positioning markings onto the surface to be sprayed, wherein the positioning markings are grid lines; UAV spraying equipment: including a UAV equipped with a camera and spraying equipment, with the surface to be sprayed and the positioning mark within the field of view of the camera; Controller: Connected to the camera, drone, and spray equipment respectively. The camera captures the positioning mark on the surface to be sprayed to determine whether spraying is complete. If spraying is complete, the distance between the drone and the surface to be sprayed is determined and the drone is adjusted to the next spraying position. Otherwise, the positioning mark image captured by the camera is compared with the target image to control the spray equipment path to complete the spraying. The spraying method includes the following steps: The projection equipment projects the positioning markings onto the surface to be sprayed; The drone rotates, and the camera captures and photographs the positioning mark; Determine the distance between the drone and the surface to be sprayed. If the positioning line is incomplete, adjust the drone's position and re-photograph the positioning line. If it is complete, determine whether the current position has been sprayed. If not, obtain the position information based on the current positioning line. The positioning mark is incomplete, which means that the photo is judged based on whether the four intersections of the grid lines are captured. If there are less than four intersections of the grid lines, the positioning mark is not completely captured and the distance needs to be adjusted and re-photographed. According to the position information, it is compared with the target image, and the spraying equipment is controlled to spray at that position.

2. The spraying method according to claim 1, characterized in that It also includes adjusting the drone to the next position if the current position has been sprayed.

3. The spraying method according to claim 1, wherein Determine whether the current position has been sprayed, specifically: The controller stores the positioning mark grid image of the sprayed target image. The drone takes a combined image of the entire current sprayed surface and the positioning mark grid. The controller compares the two images to obtain the spraying effect and whether the spraying is completed.

4. The spraying method according to claim 1, wherein: The controller compares the image captured by the camera with the stored positioning mark grid image, and obtains the distance based on the comparison between the captured image and the positioning mark grid.

5. The spraying method according to claim 1, characterized in that The spraying equipment is connected to the drone via a connecting rod.

6. The spraying method according to claim 1, characterized in that The grid lines are specifically a grid of N rows and M columns. Adjacent grids are separated by grid lines, and the intersections of the grid lines are marked with a combination of letters and numbers, specifically: Use different letters to indicate horizontal or vertical directions, and use numbers to indicate the number of grids; The grid lines are divided into a plurality of grid blocks, and each grid block is marked with a number from 0 to 9.

7. The spraying method according to claim 1, characterized in that The grid lines constitute N*M grids, requiring a total of N+1 horizontal grid lines and M+1 vertical grid lines. Patterns are set at the intersections of the horizontal grid lines and the vertical grid lines for marking. The patterns specifically use directional symbols or graphics, and the graphics are arrows. Multiple identical patterns are set at equal intervals on each grid line.

8. A storage medium, characterized in that: A computer program is stored thereon, characterized in that when the computer program is executed by a processing device, the spraying method according to any one of claims 1 to 7 is implemented.

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