A target for assisting unmanned aerial vehicle landing and a method for landing unmanned aerial vehicle

Abstract

The present invention discloses a target for assisting the landing of a drone and a method for landing a drone, which comprises: a first two-dimensional code, which comprises a first regular quadrilateral positioning frame and at least one marking point; a second two-dimensional code, which is completely located inside the first regular quadrilateral positioning frame; a third two-dimensional code, which is partially / completely located inside the first regular quadrilateral positioning frame; and a fourth two-dimensional code, which is completely located inside the first regular quadrilateral positioning frame. The present invention can avoid the problem of overexposure of the two-dimensional code in high-intensity light during the day and when a fill light is used at low brightness, and at the same time, the drone can detect the corresponding two-dimensional code at different heights to avoid frame drops.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicles, and more specifically, to a target for assisting unmanned aerial vehicle landing and a method for landing an unmanned aerial vehicle. Background Art

[0002] In the UAV autonomous landing mission, there are solutions that use RTK, QR code, etc. to assist the UAV to land accurately.

[0003] Although the RTK-assisted landing solution supports all-weather landing and has high accuracy, its use cost is high and there are problems such as poor signal in the wild environment. Therefore, it cannot meet the needs of diversified application scenarios. In addition, when using QR code to assist drone landing, if it is in a high-intensity light environment such as direct sunlight at noon or a low-light environment such as at night, a fill light is required.

[0004] In addition, China's application CN202110937743.1, UAV autonomous landing method and system based on nested QR codes, proposes a solution for guiding UAV landing based on nested QR codes. However, it simply fills the small QR code in the blank space of the large QR code. The large QR code is also prone to overexposure and frame loss under high-intensity light, and it also cannot meet the requirements for precise landing of UAVs. Summary of the invention

[0005] The purpose of the present invention is to provide a target for assisting drone landing and a drone landing method, which can avoid the problem of overexposure of QR codes under high-intensity light and low-brightness fill lights during the day, and at the same time enable the drone to detect the corresponding QR codes at different heights to avoid frame drops.

[0006] In order to achieve these purposes and other advantages according to the present invention, a target for assisting the landing of a drone is provided, comprising:

[0007] A first two-dimensional code, comprising a first regular quadrilateral positioning frame and at least one marking point; each side of the first regular quadrilateral positioning frame is formed by sequentially connecting n first regular quadrilateral unit frames, and the internal space of the first regular quadrilateral positioning frame is divided into (n-2)*(n-2) internal unit frames; and one side of at least one marking point is connected to the outside of the first regular quadrilateral positioning frame, and / or, or at least one marking point is completely located inside the first regular quadrilateral positioning frame; each internal unit frame is a regular quadrilateral, and the area is the same as that of the first regular quadrilateral unit frame;

[0008] A second two-dimensional code is completely located inside the first regular quadrilateral positioning frame, and the second two-dimensional code includes a second regular quadrilateral positioning frame, and the second regular quadrilateral positioning frame completely covers an internal unit frame, and the midpoint of the second regular quadrilateral positioning frame coincides with the midpoint of the internal unit frame that is completely covered by it.

[0009] Preferably, the area of ​​the marking point is 1.3-1.6 times the area of ​​the first regular quadrilateral unit frame.

[0010] Preferably, the area of ​​the second regular quadrilateral positioning frame is 1.4-1.8 times the area of ​​the first regular quadrilateral unit frame.

[0011] Preferably, the target also includes: a third two-dimensional code, which is partially / completely located inside the first regular quadrilateral positioning frame, and the third two-dimensional code includes a third regular quadrilateral positioning frame, and the midpoint of the third regular quadrilateral positioning frame coincides with a common corner point of two adjacent internal unit frames.

[0012] Preferably, the target further includes: a fourth two-dimensional code, which is completely located inside the first regular quadrilateral positioning frame, and the fourth two-dimensional code includes a fourth regular quadrilateral positioning frame, and the midpoint of the fourth regular quadrilateral positioning frame is located on an edge of a certain internal unit frame.

[0013] Preferably, the area of ​​the first regular quadrilateral unit frame>the area of ​​the second regular quadrilateral positioning frame>the area of ​​the third regular quadrilateral positioning frame>the area of ​​the fourth regular quadrilateral positioning frame.

[0014] Preferably, there is one second two-dimensional code, there are at least four third two-dimensional codes, there are at least two fourth two-dimensional codes, and the lines connecting the midpoints of the third regular quadrilateral positioning frames of all the third two-dimensional codes form a regular quadrilateral, the second two-dimensional code is located in the regular quadrilateral, and the midpoint of the second two-dimensional code coincides with the midpoint of the quadrilateral;

[0015] There is at least one fourth two-dimensional code between two adjacent third two-dimensional codes, and the midpoint of the fourth regular quadrilateral positioning frame 1 of the fourth two-dimensional code is located on the line connecting the midpoints of the third regular quadrilateral positioning frames of the two adjacent third two-dimensional codes.

[0016] Preferably, the second regular quadrilateral positioning frame is located below the midpoint of the first regular quadrilateral positioning frame, and the distance between the center point of the second regular quadrilateral positioning frame and the midpoint of the first regular quadrilateral positioning frame is 0.8-1.2 times the side length of the first regular quadrilateral unit frame.

[0017] Preferably, the target further comprises: a background layer, the first two-dimensional code, the second two-dimensional code, the third two-dimensional code and the fourth two-dimensional code are all arranged on the surface of the background layer, and the reflectivity of the background layer is 0.5-0.65.

[0018] Also included is a UAV landing control method based on the above target, which includes the following steps:

[0019] The UAV starts to land from above the target. When the UAV is in the first height interval, the UAV recognizes the first QR code in real time through an imaging device, obtains corner point information from the first QR code, and solves the corner point information to obtain the current posture information of the UAV.

[0020] The drone continues to land according to the current posture information, and in the landing process, the imaging device sequentially identifies one of the fourth two-dimensional code, the third two-dimensional code and the second two-dimensional code in real time, obtains the corresponding corner point information from the identified two-dimensional code, and solves the corner point information to obtain the current posture information of the drone. The drone adjusts its flight attitude according to the current posture information to ensure that the centers of the imaging device and the second two-dimensional code coincide with each other;

[0021] Until the drone lands on the tarmac.

[0022] The present invention has at least the following beneficial effects:

[0023] The present invention avoids the problem of overexposure of the QR code in high-intensity light during the day and when a fill light is used at low brightness by setting the position and size of the first QR code mark point, thereby improving the recognition rate of the first QR code and enabling the drone to recognize QR codes of different sizes, so that the drone can detect the corresponding QR code at different altitudes, avoid frame drops, and ensure that it lands accurately on the apron. Furthermore, the fourth QR code is located at the center of the area surrounded by the second and third QR codes, so that the drone can land in the middle of the apron. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the structure of a target used to assist the landing of a UAV in the present invention;

[0025] Figure 2 It is a schematic diagram of the structure of the first two-dimensional code in the present invention;

[0026] Figure 3 It is a schematic diagram of the structure of the second two-dimensional code, the third two-dimensional code, and the fourth two-dimensional code in the present invention;

[0027] Figure 4 This is a rendering of the target of the present invention identified by a drone at an altitude of 11 meters;

[0028] Figure 5 It is a schematic structural diagram of the background color layer in the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0030] In the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. to indicate directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0031] Embodiment 1:

[0032] like Figure 1-3 As shown, this embodiment provides a target for assisting the landing of a drone, which includes:

[0033] A first two-dimensional code 100, comprising a first regular quadrilateral positioning frame 101, at least one marking point 102 and an internal unit frame 1012, wherein each side of the first regular quadrilateral positioning frame 101 is formed by sequentially connecting n first regular quadrilateral unit frames 1011 (where n is a positive integer greater than or equal to 5, preferably, in this embodiment, n=7), and at the same time, the marking point 102 is a rectangle or a regular quadrilateral, and one side of at least one marking point 102 is connected to the outside of the first regular quadrilateral positioning frame 101, and / or, or at least one marking point 102 is completely located inside the first regular quadrilateral positioning frame 101; further, the area of ​​the marking point 102 is 1.3-1.6 times (preferably 1.4 times) the area of ​​the first regular quadrilateral unit frame 1011;

[0034] The internal space of the first regular quadrilateral positioning frame 101 is divided into (n-2)*(n-2) internal unit frames 1012, and each internal unit frame 1012 is a regular quadrilateral and has the same area as the first regular quadrilateral unit frame 1011;

[0035] A second two-dimensional code 400 is completely located inside the first regular quadrilateral positioning frame 101, and the second two-dimensional code 400 includes a second regular quadrilateral positioning frame 4011, and at least one of the second regular quadrilateral positioning frames 4011 completely covers an internal unit frame 1012, and the midpoint O1 of the second regular quadrilateral positioning frame 4011 coincides with the midpoint O of the internal unit frame 1012 completely covered by it; further, the area of ​​the second regular quadrilateral positioning frame 4011 is 1.4-1.8 times (preferably 1.5 times) the area of ​​the first regular quadrilateral unit frame 1011;

[0036] A third two-dimensional code 300, which is partially / completely located inside the first regular quadrilateral positioning frame 101, and the third two-dimensional code 300 includes a third regular quadrilateral positioning frame 3011, and a midpoint O2 of the third regular quadrilateral positioning frame 3011 coincides with a common corner point O3 of two adjacent internal unit frames 1012;

[0037] and a fourth two-dimensional code 200, which is completely located inside the first regular quadrilateral positioning frame 101, and the fourth two-dimensional code 200 includes a fourth regular quadrilateral positioning frame 2011, and the midpoint O4 of the fourth regular quadrilateral positioning frame 2011 is located on an edge of a certain internal unit frame 1012, preferably, the midpoint O4 of the fourth regular quadrilateral positioning frame 2011 coincides with the midpoint O5 of an edge of a certain internal unit frame 1012;

[0038] The area of ​​the first regular quadrilateral unit frame 1011>the area of ​​the second regular quadrilateral positioning frame 4011>the area of ​​the third regular quadrilateral positioning frame 3011>the area of ​​the fourth regular quadrilateral positioning frame 2011, the first regular quadrilateral unit frame 1011, the second regular quadrilateral positioning frame 4011, the third regular quadrilateral positioning frame 3011, the fourth regular quadrilateral positioning frame 2011, and the marking point 102 are all black. And the second two-dimensional code 400, the third two-dimensional code 300, and the fourth two-dimensional code 200 can have multiple.

[0039] The drone can obtain the parameter information contained in the first QR code 100 by identifying the marker point 102, and the parameter information includes the QR code number information, etc. In the prior art, the first regular quadrilateral positioning frame 101 and the marker point 102 have the same area. Therefore, in environments such as high-intensity light and low-brightness using a fill light, the first regular quadrilateral positioning frame 101 is clearly visible, while the various scattered marker points 102 are very easy to be overexposed and cannot be identified, which results in the inability to obtain the parameter information contained in the first QR code 100. In this embodiment, the area of ​​the marker point 102 is set to 1.3-1.6 times the area of ​​the first regular quadrilateral unit frame 1011. When overexposed due to high-intensity light, the edge area of ​​the marker point 102 turns white, and the final effect presented in the imaging device is that the marker point 102 is basically the same size as the first regular quadrilateral unit frame 1011 (such as Figure 4 As shown), the landmark point 102 can be successfully identified and further analyzed to obtain parameter information.

[0040] Furthermore, in this embodiment, the second regular quadrilateral positioning frame 4011 is always located inside the first regular quadrilateral unit frame 1011, and the midpoints of the third regular quadrilateral positioning frame 3011 and the fourth regular quadrilateral positioning frame 2011 are always located on the edge of the internal unit frame 1012. Therefore, the second two-dimensional code 400, the third two-dimensional code 300 and the fourth two-dimensional code 200 will not affect the recognition of the landmark point 101 of the first two-dimensional code 100, thereby greatly improving the recognition accuracy and efficiency.

[0041] In addition, the area of ​​the second regular quadrilateral positioning frame 4011 is 1.4-1.8 times the area of ​​the first regular quadrilateral unit frame 1011. Therefore, when identifying the second two-dimensional code 400, it can be quickly distinguished from the surrounding internal unit frame 1012 to quickly identify the second two-dimensional code 400 and avoid recognition errors of the second two-dimensional code 400.

[0042] Embodiment 2:

[0043] The difference between this embodiment and embodiment 1 is that Figure 1 ,3, there is one second two-dimensional code 400, there are at least four third two-dimensional codes 300, there are at least two fourth two-dimensional codes 200, and the line connecting the midpoints of the third regular quadrilateral positioning frames 3011 of all the third two-dimensional codes 300 forms a regular quadrilateral, the second two-dimensional code 400 is located in the regular quadrilateral, and the midpoint of the second two-dimensional code 400 coincides with the midpoint of the quadrilateral;

[0044] At the same time, there is at least one fourth two-dimensional code 200 between two adjacent third two-dimensional codes 300, and the midpoint O4 of the fourth regular quadrilateral positioning frame 2011 of the fourth two-dimensional code 200 is located on the line connecting the midpoints of the third regular quadrilateral positioning frames 3011 of the two adjacent third two-dimensional codes 300; and the second regular quadrilateral positioning frame 4011 is located below the midpoint O6 of the first regular quadrilateral positioning frame 101, and the distance between the center point O1 of the second regular quadrilateral positioning frame 4011 and the midpoint O6 of the first regular quadrilateral positioning frame 101 is 0.8-1.2 times the side length of the first regular quadrilateral unit frame 1011.

[0045] Since the drone needs to land in the middle of the apron, and the drone's imaging device is generally set at a position behind the center of the drone in order not to interfere with the gimbal, and the center of the area enclosed by the third two-dimensional code 300 and the fourth two-dimensional code 200 in this embodiment (that is, the center of the second two-dimensional code 400) is also located below the center of the entire two-dimensional code target. Therefore, when the drone lands, it can land under the guidance of the second two-dimensional code 400 through the imaging device, and keep the centers of the imaging device and the second two-dimensional code 400 as close as possible to each other during the landing process. Therefore, after the drone lands on the apron, the center of the drone's imaging device is basically located at the center of the area enclosed by the third two-dimensional code 300 and the fourth two-dimensional code 200, and at the same time ensures that the center of the drone as a whole coincides with the center of the apron, so that the drone lands in the middle of the apron.

[0046] Embodiment 3:

[0047] The difference between this embodiment and embodiment 1 or 2 is that Figure 5 As shown, the target also includes a base layer 500, and the first two-dimensional code 100, the second two-dimensional code 400, the third two-dimensional code 300, and the fourth two-dimensional code 200 are all arranged on the surface of the base layer 500. Furthermore, the reflectivity of the base layer 500 is 0.5-0.65 to effectively prevent the two-dimensional code from being overexposed.

[0048] Embodiment 4:

[0049] This embodiment provides a method for controlling a drone landing based on the target described in any one of Embodiments 1 to 3, which comprises the following steps:

[0050] The drone starts to land from above the target. When the drone is in the first height interval, the drone recognizes the first two-dimensional code 100 in real time through an imaging device, obtains corner point information from the first two-dimensional code 100, and solves the corner point information to obtain the current posture information of the drone (the method of solving the corner point information to obtain the posture of the drone based on the two-dimensional code information belongs to the prior art and will not be repeated here). The corner point information includes: corner point information of the marker point 102 and / or corner point information of the first regular quadrilateral unit frame 1011;

[0051] The drone continues to land according to the current posture information, and in the landing process, the fourth two-dimensional code 400, the third two-dimensional code 300 and the second two-dimensional code 200 are sequentially identified in real time by the imaging device, and the corresponding corner point information is obtained from the identified two-dimensional code, and the corner point information is solved to obtain the current posture information of the drone. The drone adjusts the flight attitude according to the current posture information to ensure that the centers of the imaging device and the second two-dimensional code 400 coincide with each other;

[0052] Until the drone lands on the apron.

[0053] Therefore, after adopting the target in the present invention, even if the drone is in a high-intensity light environment, it can still detect the first two-dimensional code 100 and will not be affected by overexposure. During the process of landing at a low altitude (for example, landing at a height of 0.5m), the field of view of the imaging device becomes smaller, but the drone can still adjust its flight attitude by detecting the smaller fourth two-dimensional code 400, the third two-dimensional code 300 and the second two-dimensional code 200. Moreover, since multiple third two-dimensional codes 300 and fourth two-dimensional codes 200 surround the fourth two-dimensional code 400, even if the drone is shifted in position under the action of wind, it can still detect the third two-dimensional code 300 and the second two-dimensional code 200 around the fourth two-dimensional code 400 to avoid completely losing the target.

[0054] In summary, the present invention can avoid the problem of overexposure of the QR code in high-intensity light during the day and low-brightness situations when using a fill light by adjusting the position and size of the first QR code mark point, thereby improving the recognition rate of the first QR code, and at the same time making the fourth QR code located at the center of the area enclosed by the second QR code and the third QR code, so that the UAV can land in the middle of the apron; further, the area of ​​the positioning frame of the first to fourth QR codes is gradually reduced, so that the UAV can detect the corresponding QR code at different heights, avoiding frame drops, and adjusting the position according to the corner point information of the QR code to ensure that it lands accurately on the apron.

[0055] It should be noted that the technical features in the above-mentioned embodiments 1-4 can be combined arbitrarily, and the combined technical solutions all belong to the protection scope of this application. Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation mode. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, other modifications can be easily realized. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to the specific details and the drawings shown and described here.

Claims

1. A target for assisting the landing of a drone, characterized in that: include: A first two-dimensional code, comprising a first regular quadrilateral positioning frame and at least one marking point; Each side of the first regular quadrilateral positioning frame is formed by sequentially connecting n first regular quadrilateral unit frames, and the internal space of the first regular quadrilateral positioning frame is divided into (n-2)*(n-2) internal unit frames; and one side of at least one marking point is connected to the outside of the first regular quadrilateral positioning frame, and / or at least one marking point is completely located inside the first regular quadrilateral positioning frame; each internal unit frame is a regular quadrilateral, and the area is the same as that of the first regular quadrilateral unit frame; A second two-dimensional code, which is completely located inside the first regular quadrilateral positioning frame, and the second two-dimensional code includes a second regular quadrilateral positioning frame, and the second regular quadrilateral positioning frame completely covers an internal unit frame, and the midpoint of the second regular quadrilateral positioning frame coincides with the midpoint of the internal unit frame completely covered by the second regular quadrilateral positioning frame; a third two-dimensional code, which is partially / completely located inside the first regular quadrilateral positioning frame, and the third two-dimensional code includes a third regular quadrilateral positioning frame, and a midpoint of the third regular quadrilateral positioning frame coincides with a common corner point of two adjacent internal unit frames; a fourth two-dimensional code, which is completely located inside the first regular quadrilateral positioning frame, and the fourth two-dimensional code includes a fourth regular quadrilateral positioning frame, and the midpoint of the fourth regular quadrilateral positioning frame is located on an edge of a certain internal unit frame; The area of ​​the first regular quadrilateral unit frame>the area of ​​the second regular quadrilateral positioning frame>the area of ​​the third regular quadrilateral positioning frame>the area of ​​the fourth regular quadrilateral positioning frame.

2. The target according to claim 1, characterized in that The area of ​​the marking point is 1.3-1.6 times the area of ​​the first regular quadrilateral unit frame.

3. The target according to claim 1, characterized in that There is one second two-dimensional code, at least four third two-dimensional codes, at least two fourth two-dimensional codes, and a line connecting the midpoints of the third regular quadrilateral positioning frames of all the third two-dimensional codes forms a regular quadrilateral, the second two-dimensional code is located in the regular quadrilateral, and the midpoint of the second two-dimensional code coincides with the midpoint of the quadrilateral; There is at least one fourth two-dimensional code between two adjacent third two-dimensional codes, and the midpoint of the fourth regular quadrilateral positioning frame 1 of the fourth two-dimensional code is located on the line connecting the midpoints of the third regular quadrilateral positioning frames of the two adjacent third two-dimensional codes.

4. The target according to claim 1, characterized in that The second regular quadrilateral positioning frame is located below the midpoint of the first regular quadrilateral positioning frame, and the distance between the center point of the second regular quadrilateral positioning frame and the midpoint of the first regular quadrilateral positioning frame is 0.8-1.2 times the side length of the first regular quadrilateral unit frame.

5. The target according to claim 1, characterized in that The target further includes: a background layer, the first two-dimensional code, the second two-dimensional code, the third two-dimensional code, and the fourth two-dimensional code are all arranged on the surface of the background layer, and the reflectivity of the background layer is 0.5-0.

65.

6. A method for controlling the landing of an unmanned aerial vehicle based on the target according to any one of claims 1 to 5, characterized in that: The steps include: The UAV starts to land from above the target. When the UAV is in the first height interval, the UAV recognizes the first QR code in real time through an imaging device, obtains corner point information from the first QR code, and solves the corner point information to obtain the current posture information of the UAV. The drone continues to land according to the current posture information, and in the landing process, the imaging device sequentially identifies one of the fourth two-dimensional code, the third two-dimensional code and the second two-dimensional code in real time, obtains the corresponding corner point information from the identified two-dimensional code, and solves the corner point information to obtain the current posture information of the drone. The drone adjusts its flight attitude according to the current posture information to ensure that the centers of the imaging device and the second two-dimensional code coincide with each other; Until the drone lands on the apron.

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