Multi-angle chlorophyll fluorescence measurement system and method based on unmanned aerial vehicle remote sensing

Abstract

The invention relates to the technical field of plant measurement, and provides a multi-angle chlorophyll fluorescence measurement system and method based on unmanned aerial vehicle remote sensing, the system comprises an unmanned aerial vehicle, an undercarriage and an acquisition probe, the undercarriage comprises a plurality of strip-shaped frames which are uniformly distributed in the circumferential direction, each strip-shaped frame is provided with an extension piece in a clamping manner, and the extension pieces are connected with the unmanned aerial vehicle; each extension piece is provided with a ground supporting rod with adjustable length; a protective cylinder is arranged on the unmanned aerial vehicle body, one end of the protective cylinder is open and is provided with an adaptive cover plate, and the acquisition probe is arranged on the cover plate through a probe bracket in an angle adjustable manner; when the unmanned aerial vehicle lands, the whole undercarriage is unfolded, meanwhile, the cover plate is switched to the protection station so that the collection probe can move into the protection barrel, the dust blocking effect is achieved through the protection barrel, then the unmanned aerial vehicle is controlled to gradually land till the unmanned aerial vehicle keeps a certain height from the ground, and then each ground supporting rod extends to the end to make contact with the ground falling point. And finally controlling and stopping propellers of the unmanned aerial vehicle to realize stable landing.

Description

Technical Field

[0001] The present invention relates to the field of plant measurement technology, and in particular to a multi-angle chlorophyll fluorescence measurement system and method based on unmanned aerial vehicle remote sensing. Background Art

[0002] In the field of plant measurement, chlorophyll fluorescence, as an important indicator reflecting the efficiency of plant photosynthesis, is of great significance for monitoring plant health, evaluating ecosystem functions and studying plant response mechanisms under environmental stress. In recent years, with the rapid development of drone technology, chlorophyll fluorescence measurement systems based on drone remote sensing technology have gradually become a research hotspot.

[0003] In actual measurement applications, since most outdoor ground is uneven, drones can easily fall over due to uneven ground when landing (such as changing batteries, inspecting the body, etc.), causing damage to the drone, which in turn affects the subsequent measurement tasks. Although there are drone take-off and landing platforms, these platforms are usually large in size and heavy in weight, and need to be carried all the time during outdoor measurement work, which brings great inconvenience to researchers and operators; in addition, chlorophyll fluorescence data acquisition probes are usually directly installed on the drone body. When the drone lands close to the ground, the airflow generated by the rotation of its propellers will raise dust and tiny particles, which can easily adhere to the collection probe to form a shielding layer, interfering with the accurate capture of the fluorescence signal, thereby affecting the accuracy of chlorophyll fluorescence measurement.

[0004] Therefore, the present invention proposes a multi-angle chlorophyll fluorescence measurement system and method based on UAV remote sensing to solve the above problems. Summary of the invention

[0005] The embodiment of the present invention aims to provide a multi-angle chlorophyll fluorescence measurement system and method based on UAV remote sensing to solve the above problems.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing, comprising a UAV, a landing gear arranged on the UAV body, and a collection probe for collecting chlorophyll fluorescence data, and also comprising a processing terminal located on the ground for receiving fluorescence data and analyzing and processing, wherein the landing gear can be expanded / retracted, and the landing gear comprises a plurality of strip frames evenly distributed in the circumferential direction, each of the strip frames is provided with an extension piece that can slide toward / away from the center of the plurality of strip frames, and each of the extension pieces is provided with a ground support rod with adjustable length;

[0008] A protective tube is provided on the drone body, and one end of the protective tube away from the drone body is open and provided with an adaptive cover. The collection probe is arranged on the cover in an angle-adjustable manner through a probe bracket. The cover is provided with two positions: collection and protection. When the cover is in the collection position, the collection probe is outside the protective tube. When the cover is in the protection position, the cover closes the open end of the protective tube and the collection probe is inside the protective tube.

[0009] In an optional solution: the processing terminal includes a receiving module for receiving fluorescence data in real time, a processing module for analyzing and processing the received fluorescence data, and a user interface.

[0010] In an optional solution, the chlorophyll fluorescence data is transmitted in real time between the collection probe and the receiving module via radio communication.

[0011] In an optional solution: the landing gear also includes an annular electromagnet arranged at the center of the multi-track strip frame, and each of the extension members is provided with a magnetic block at one end close to the annular electromagnet.

[0012] In an optional solution: each of the strip frames is provided with a knob for positioning the corresponding extension member.

[0013] In an optional scheme: the ground support rod includes a cylinder and a sealing piston arranged in the cylinder, the lower end of the cylinder is closed and the upper end is open, the sealing piston is provided with a support column, the lower end of the support column seals and passes through the closed end of the cylinder and is provided with a ground contact block, the landing gear also includes a diverter and a two-way air pump, the two-way air pump filling / exhaust port is connected to the diverter, an air pipe is provided between the diverter and each cylinder, and a sealing valve is provided on each air pipe, a pressure sensor is provided between the support column and the ground contact block, when the pressure sensor senses that the pressure value reaches a set value, the sealing valve on the corresponding air pipe is closed.

[0014] In an optional solution, the air guide tube is formed by sealingly sleeved at least two matching hard pipes.

[0015] In an optional scheme: the measurement system also includes a switching component for realizing the switching of the cover plate position, the switching component includes an iron slider arranged in the protective tube, a magnetic ring arranged at the open end of the protective tube and a pull rope arranged on the iron slider, the end of the pull rope away from the iron slider passes through the wall of the protective tube and is fixed on any extending member, a connecting rod is provided between the iron slider and the cover plate, when the landing gear is in a retracted state, the cover plate is in the collection position, and when the landing gear is in an extended state, the cover plate is in the protection position.

[0016] A chlorophyll fluorescence measurement method, using a multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing as described in any one of the above technical solutions, comprises the following steps:

[0017] S1: The drone is equipped with a collection probe and flies over the collection area according to the set trajectory to collect chlorophyll fluorescence data of plants in the area. During the collection operation, according to the actual measurement needs, the collection angle is adjusted by controlling the drone and the probe bracket to drive the collection probe to deflect and coordinate with each other to achieve multi-angle chlorophyll fluorescence measurement; when the drone lands, first, each extension piece slides into place toward the center of the multi-channel strip frame, and the landing gear is unfolded as a whole. At the same time, the cover is switched to the protection position so that the collection probe moves to the inside of the protective tube, and the dust is blocked by the protective tube. Then the drone is controlled to gradually descend to maintain a certain height from the ground, and then each supporting rod is extended until the end contacts the ground landing point. Finally, the drone propeller is controlled to shut down to achieve a smooth landing;

[0018] S2: The collected fluorescence data is transmitted to the processing terminal in real time for analysis and processing.

[0019] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows:

[0020] 1. When the drone is landing, first, each extension piece slides toward the center of the multi-channel strip frame and the landing gear is unfolded as a whole. At the same time, the cover piece is switched to the protection position so that the collection probe is moved into the protective tube. Then the drone is controlled to gradually descend to maintain a certain height from the ground. Then each ground support rod is extended until the end touches the ground landing point. Finally, the drone propeller is controlled to shut down to achieve a smooth landing.

[0021] 2. The protective tube can block dust and prevent the dust raised by the propeller from adhering to the collection probe during landing, ensuring that the collection probe can accurately capture the fluorescence signal.

[0022] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into and constitute a part of the specification to illustrate embodiments consistent with the present application and are used together with the specification to explain the principles of the present application. At the same time, these drawings and text descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application for those skilled in the art by referring to specific embodiments.

[0024] Figure 1 It is a front view of an embodiment of the present invention.

[0025] Figure 2 It is a top view of an embodiment of the present invention.

[0026] Figure 3 It is a schematic diagram of the arrangement among the landing gear, the protective tube and the collection probe in an embodiment of the present invention.

[0027] Figure 4 This is a schematic diagram of another angle arrangement between the landing gear, the protective tube and the collection probe in an embodiment of the present invention.

[0028] Figure 5 Schematic diagram of the structure of the ground support rod in an embodiment of the present invention.

[0029] Figure 6 It is a schematic diagram of the arrangement among the transposition component, the protective tube, the cover plate and the collection probe in an embodiment of the present invention.

[0030] Notes on figure numbers: 1-UAV, 2-landing gear, 201-bar frame, 202-extension piece, 203-cylinder, 204-touchdown block, 205-ring electromagnet, 206-magnetic block, 207-diverter, 208-air guide tube, 209-knob, 210-sealing piston, 211-support column, 212-bidirectional air pump, 3-collection probe, 4-protective tube, 5-probe bracket, 6-cover plate, 7-transposition assembly, 701-iron slider, 702-magnetic ring, 703-connecting rod, 704-pulling rope. DETAILED DESCRIPTION

[0031] The present application is further described in detail below in conjunction with the accompanying drawings. It is necessary to point out here that the following specific implementation methods are only used to further illustrate the present application and cannot be understood as limiting the scope of protection of the present application. Technical personnel in this field can make some non-essential improvements and adjustments to the present application based on the above application content.

[0032] See also Figure 1 to Figure 3 A multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing, comprising a UAV 1, a landing gear 2 arranged on the body of the UAV 1, and a collection probe 3 for collecting chlorophyll fluorescence data, and also comprising a processing terminal located on the ground for receiving fluorescence data and analyzing and processing, wherein the landing gear 2 can be expanded / retracted, and the landing gear 2 comprises a plurality of circumferentially evenly distributed strip frames 201, each of which is provided with an extension piece 202 that can slide away from / towards the center of the plurality of strip frames 201, and each of which is provided with a ground support rod with adjustable length;

[0033] A protective tube 4 is provided on the body of the drone 1. The end of the protective tube 4 away from the body of the drone 1 is open and provided with an adaptive cover 6. The collection probe 3 is arranged on the cover 6 in an angle-adjustable manner through a probe bracket 5. The cover 6 is provided with two positions: collection and protection. When the cover 6 is in the collection position, the collection probe 3 is outside the protective tube 4. When the cover 6 is in the protection position, the cover 6 closes the open end of the protective tube 4 and the collection probe 3 is inside the protective tube 4.

[0034] It should be noted that the probe bracket 5 is an electric bracket, which can drive the collection probe 3 to deflect to adjust the angle. This is a prior art and will not be described in detail here.

[0035] The drone 1 is equipped with a collection probe 3 and flies over the collection area according to a set trajectory to collect chlorophyll fluorescence data of plants in the area. The collected fluorescence data is transmitted to the processing terminal in real time for analysis and processing. During the collection operation, according to the actual measurement needs, the drone 1 and the probe bracket 5 are controlled to drive the collection probe 3 to deflect and coordinate with each other to adjust the collection angle, thereby realizing multi-angle chlorophyll fluorescence measurement; when the drone 1 lands, first, each extension member 202 slides into place toward the center of the multi-channel strip frame 201, and the landing gear 2 is unfolded as a whole. At the same time, the cover plate 6 is switched to the protection position to move the collection probe 3 to the inside of the protection tube 4, and then the drone 1 is controlled to gradually Land to a certain height from the ground (such as 15 cm, 20 cm, etc., as long as the end of the ground support rod can touch the ground when the length of the ground support rod is adjusted), then extend each ground support rod (when flying, each ground support rod is in a retracted initial state) until the end touches the ground landing point (when the ground landing point is more convex, the corresponding ground support rod is adjusted to have a shorter overall length; when the ground landing point is more concave, the corresponding ground support rod is adjusted to have a longer overall length), finally control and shut down the propeller of the drone 1 to achieve a smooth landing, and use the protective tube 4 to block dust, so as to prevent the dust raised by the propeller during landing from adhering to the collection probe 3, thereby ensuring that the collection probe 3 accurately captures the fluorescence signal.

[0036] Furthermore, the processing terminal includes a receiving module for receiving fluorescence data in real time, a processing module for analyzing and processing the received fluorescence data, and a user interface. The chlorophyll fluorescence data is transmitted in real time between the acquisition probe 3 and the receiving module via radio communication. After receiving the fluorescence data, the processing module calculates relevant fluorescence parameters based on the fluorescence signal, and uses the known chlorophyll content or other physiological parameters and the relationship between the fluorescence parameters to establish an inversion model, and estimates the chlorophyll content and other physiological parameters of the vegetation through the model. The above are all existing technologies and will not be elaborated here.

[0037] See also Figure 3In one embodiment of the present invention, the landing gear 2 also includes an annular electromagnet 205 arranged at the center of the multi-track strip frame 201, and each of the extension members 202 is provided with a magnetic block 206 at one end close to the annular electromagnet 205, and the magnetic pole of the magnetic block 206 is divided into half sides close to / far away from the annular electromagnet 205.

[0038] In this embodiment, the magnetic pole of the annular electromagnet 205 facing the magnetic block 206 is changed by controlling the direction of the current. Under the principle of like poles repel and unlike poles attract, when the UAV 1 is flying, the magnetic pole of the annular electromagnet 205 facing the half side of the magnetic block 206 is opposite to the magnetic pole of the half side of the magnetic block 206 facing the annular electromagnet 205. The annular electromagnet 205 generates an adsorption force on the magnetic block 206, so that all the extending parts 202 slide into place close to the center of the multi-track strip frame 201, that is, the landing gear 2 shrinks as a whole, thereby reducing the flight resistance. When the UAV 1 lands, the direction of the current is changed so that the magnetic pole of the annular electromagnet 205 facing the half side of the magnetic block 206 is the same as the magnetic pole of the half side of the magnetic block 206 facing the annular electromagnet 205. The annular electromagnet 205 generates a repulsive force on the magnetic block 206, so that all the extending parts 202 slide into place away from the center of the multi-track strip frame 201, that is, the landing gear 2 is unfolded as a whole to prepare for landing.

[0039] Furthermore, in this embodiment, each of the strip frames 201 is provided with a knob 209 for positioning the corresponding extension member 202. When the annular electromagnet 205 is powered off (no collection operation is performed), all the extension members 202 slide into place close to the strip frame 201 and are positioned by tightening the knob 209, thereby preventing the extension members 202 from sliding and bumping during carrying.

[0040] See also Figure 1 , Figure 2 to Figure 5 In one embodiment of the present invention, the ground support rod includes a cylinder 203 and a sealing piston 210 arranged in the cylinder 203, the cylinder 203 is closed at the lower end and open at the upper end, a support column 211 is arranged on the sealing piston 210, the lower end of the support column 211 seals and passes through the closed end of the cylinder 203 and is provided with a ground contact block 204, the landing gear 2 also includes a diverter 207 and a two-way air pump 212, the filling / exhaust port of the two-way air pump 212 is connected to the diverter 207, an air guide tube 208 is arranged between the diverter 207 and each cylinder 203, and a sealing valve is arranged on each air guide tube 208, preferably, the sealing valve is a solenoid valve, a pressure sensor is arranged between the support column 211 and the ground contact block 204 (not shown in the figure), when the pressure sensor senses that the pressure value reaches the set value, the sealing valve on the corresponding air guide tube 208 is closed.

[0041] In this embodiment, when the UAV 1 is in flight, the support column 211 is retracted in the cylinder 203, that is, the initial position. When landing, the two-way air pump 212 is used to extract the gas in the cylinder 203 to make the sealing piston 210 move downward, thereby driving the support column 211 and the touchdown block 204 to move downward. When the touchdown block 204 touches the ground, the corresponding pressure sensor will sense the pressure. When the sensed pressure value reaches the set value, it means that the length of the corresponding support rod is adjusted in place, thereby controlling the sealing valve on the corresponding air guide tube 208 to close and no longer pump air (this is achieved by the existing control technology, there is no technical obstacle, and it will not be repeated here). When all the touchdown blocks 204 touch the ground, the propeller of the UAV 1 is controlled to be shut down to achieve a smooth landing. During flight, the two-way air pump 212 is used to inject air into the cylinder 203 to make the sealing piston 210 move up and reset, that is, drive the support column 211 to retract into the cylinder 203 and reset.

[0042] Furthermore, in this embodiment, the air guide tube 208 is formed by sealingly sleeved at least two matching hard pipes, and can be adaptively extended and retracted as the extension member 202 slides.

[0043] Furthermore, in this embodiment, the pressure sensor model is: CYT-206.

[0044] See also Figure 3 and Figure 6 In one embodiment of the present invention, the measuring system further includes a position switching component 7 for realizing the position switching of the cover piece 6, the position switching component 7 includes an iron slider 701 arranged in the protective tube 4, a magnetic ring 702 arranged at the open end of the protective tube 4 and a drag rope 704 arranged on the iron slider 701, the end of the drag rope 704 away from the iron slider 701 passes through the wall of the protective tube 4 and is fixed on any extending member 202, a connecting rod 703 is provided between the iron slider 701 and the cover piece 6, when the landing gear 2 is in a retracted state, the cover piece 6 is in a collection position, and when the landing gear 2 is in an extended state, the cover piece 6 is in a protection position.

[0045] In this embodiment, during measurement, the landing gear 2 is in a retracted state, and the magnetic ring 702 magnetically attracts the iron slider 701 to position it, and the collection probe 3 is located outside the protective tube 4. During landing, the landing gear 2 is unfolded, that is, all the extension members 202 slide toward the center of the multi-track strip frame 201, thereby pulling the pull rope 704 to move the iron slider 701 away from the open end of the protective tube 4. When the extension members 202 slide into place away from the center of the multi-track strip frame 201, the cover plate 6 is just moved to the protection position, so that the collection probe 3 is moved into the protective tube 4 to prevent dust.

[0046] The present invention also provides a chlorophyll fluorescence measurement method, which adopts a multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to any one of the above technical solutions, comprising the following steps:

[0047] S1: The drone 1 is equipped with a collection probe 3 and flies over the collection area according to the set trajectory to collect chlorophyll fluorescence data of plants in the area. During the collection operation, according to the actual measurement needs, the drone 1 and the probe bracket 5 are controlled to drive the collection probe 3 to deflect and coordinate with each other to adjust the collection angle, so as to achieve multi-angle chlorophyll fluorescence measurement; when the drone 1 lands, first, each extension member 202 slides into place away from the center of the multi-channel strip frame 201, and the landing gear 2 is unfolded as a whole. At the same time, the cover plate 6 is switched to the protection position so that the collection probe 3 moves to the inside of the protective tube 4, and the dust is blocked by the protective tube 4, and then the drone 1 is controlled to gradually descend to maintain a certain height from the ground, and then each supporting rod is extended until the end contacts the ground landing point, and finally the propeller of the drone 1 is controlled to be shut down to achieve a smooth landing;

[0048] S2: The collected fluorescence data is transmitted to the processing terminal in real time for analysis and processing.

[0049] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A multi-angle chlorophyll fluorescence measurement system based on unmanned aerial vehicle remote sensing, comprising an unmanned aerial vehicle (1), a landing gear (2) arranged on the body of the unmanned aerial vehicle (1), and a collection probe (3) for collecting chlorophyll fluorescence data, and also comprising a processing terminal located on the ground for receiving fluorescence data and analyzing and processing, characterized in that: The landing gear (2) can be expanded / retracted, and the landing gear (2) comprises a plurality of strip frames (201) uniformly distributed in the circumferential direction, each of the strip frames (201) is provided with an extension piece (202) that can slide toward / away from the center of the plurality of strip frames (201), and each of the extension pieces (202) is provided with a ground support rod with adjustable length; The drone (1) is provided with a protective tube (4), one end of the protective tube (4) away from the drone (1) is open and provided with a matching cover sheet (6), the acquisition probe (3) is arranged on the cover sheet (6) in an angle-adjustable manner via a probe bracket (5), the cover sheet (6) is provided with two workstations: acquisition and protection. When the cover sheet (6) is in the acquisition workstation, the acquisition probe (3) is located outside the protective tube (4), and when the cover sheet (6) is in the protection workstation, the cover sheet (6) closes the open end of the protective tube (4) and the acquisition probe (3) is located inside the protective tube (4).

2. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 1 is characterized in that: The processing terminal includes a receiving module for receiving fluorescence data in real time, a processing module for analyzing and processing the received fluorescence data, and a user interface.

3. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 2 is characterized in that: The chlorophyll fluorescence data is transmitted in real time between the collection probe (3) and the receiving module via radio communication.

4. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 1 is characterized in that: The landing gear (2) further comprises an annular electromagnet (205) arranged at the center of the multi-lane strip frame (201), and a magnetic block (206) is arranged at one end of each extension member (202) close to the annular electromagnet (205).

5. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 4 is characterized in that: Each of the strip frames (201) is provided with a knob (209) for positioning the corresponding extension member (202).

6. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 1 is characterized in that: The ground support rod comprises a cylinder (203) and a sealing piston (210) arranged in the cylinder (203); the cylinder (203) is closed at the lower end and open at the upper end; a support column (211) is arranged on the sealing piston (210); the lower end of the support column (211) seals and penetrates the closed end of the cylinder (203) and is provided with a ground contact block (204); the landing gear (2) also comprises a flow divider (207) and a two-way air pump (212); the filling / exhausting port of the two-way air pump (212) is connected to the flow divider (207); an air guide tube (208) is arranged between the flow divider (207) and each cylinder (203); and a sealing valve is arranged on each air guide tube (208); a pressure sensor is arranged between the support column (211) and the ground contact block (204); when the pressure sensor senses that the pressure value reaches a set value, the sealing valve on the corresponding air guide tube (208) is closed.

7. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 6 is characterized in that: The air guide tube (208) is formed by sealingly sleeved at least two matching hard pipes.

8. The multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing according to claim 1 is characterized in that: The measurement system further comprises a position switching component (7) for realizing the position switching of the cover plate (6), the position switching component (7) comprising an iron slider (701) arranged in the protective tube (4), a magnetic ring (702) arranged at the open end of the protective tube (4), and a drag rope (704) arranged on the iron slider (701), the end of the drag rope (704) away from the iron slider (701) passes through the wall of the protective tube (4) and is fixed on any extension member (202), a connecting rod (703) is arranged between the iron slider (701) and the cover plate (6), when the landing gear (2) is in a retracted state, the cover plate (6) is in a collection position, and when the landing gear (2) is in an extended state, the cover plate (6) is in a protection position.

9. A chlorophyll fluorescence measurement method, using the multi-angle chlorophyll fluorescence measurement system based on UAV remote sensing as described in any one of claims 1 to 8, characterized in that: The following steps are involved: S1: The drone (1) is equipped with a collection probe (3) and flies over the collection area according to a set trajectory to collect chlorophyll fluorescence data of plants in the area. During the collection operation, according to the actual measurement requirements, the drone (1) and the probe bracket (5) are controlled to drive the collection probe (3) to deflect and coordinate with each other to adjust the collection angle, so as to achieve multi-angle chlorophyll fluorescence measurement; when the drone (1) lands, first, each extension member (202) slides into place away from the center of the multi-channel strip frame (201), and the landing gear (2) is fully unfolded. At the same time, the cover plate (6) is switched to the protection position so that the collection probe (3) moves to the inside of the protection tube (4), and the dust is blocked by the protection tube (4). Then, the drone (1) is controlled to gradually descend to maintain a certain height from the ground, and then each ground support rod is extended until the end contacts the ground landing point. Finally, the propeller of the drone (1) is controlled to be shut down to achieve a smooth landing; S2: The collected fluorescence data is transmitted to the processing terminal in real time for analysis and processing.

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