Aerial dispersal device

Abstract

This specification provides an aerial spraying device capable of spraying chemicals while accurately maintaining the nozzle's altitude relative to the ground surface at a predetermined set altitude. [Solution] The aerial spraying device disclosed herein comprises a main body, a rotor attached to the main body that generates lift, a nozzle for spraying chemicals located below the main body, a retractable support column connecting the main body and the nozzle, an altitude sensor that measures the altitude from the ground to the main body, and a controller that controls the support column based on the measurement value of the altitude sensor so that the altitude of the nozzle from the ground is a predetermined set altitude. By controlling the support column according to the measurement value of the altitude sensor, the aerial spraying device disclosed herein is able to spray chemicals while accurately maintaining the altitude of the nozzle relative to the ground at a predetermined set altitude.

Description

Technical Field

[0001] The technology disclosed in this specification relates to an aerial spraying device for spraying medicine into the air.

Background Art

[0002] Devices for spraying medicines such as agricultural chemicals are disclosed in Patent Documents 1 and 2. Patent Document 1 discloses a drone helicopter equipped with a nozzle for spraying. The drone helicopter has a lifting device, and a nozzle is attached to the tip of the lifting device. The nozzle moves up and down relative to the main body of the drone helicopter by the lifting device. When spraying medicine, the nozzle is lowered. By lowering the nozzle, the influence of the downward airflow generated by the rotation of the rotor of the drone helicopter on the spraying of the medicine can be reduced.

[0003] Patent Document 2 discloses a multicopter with a medicine spraying device suspended. By suspending the medicine spraying device, it is possible to spray the medicine at a position lower than the height of the obstacle while holding the multicopter at a position higher than the obstacle placed on the ground.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the devices disclosed in Patent Documents 1 and 2, the height of the nozzle relative to the ground surface cannot be accurately maintained at a predetermined set height. This specification provides an aerial spraying device capable of accurately maintaining the height of the nozzle relative to the ground surface at a predetermined set height while spraying medicine.

Means for Solving the Problems

[0006] The aerial spraying device disclosed herein comprises a main body, a rotor attached to the main body that generates lift, a nozzle for spraying chemicals located below the main body, a retractable support column connecting the main body and the nozzle, an altitude sensor that measures the altitude from the ground to the main body, and a controller that controls the support column based on the measurement value of the altitude sensor so that the altitude of the nozzle from the ground is a predetermined set altitude. By controlling the support column according to the measurement value of the altitude sensor, the aerial spraying device disclosed herein can spray chemicals while accurately maintaining the altitude of the nozzle relative to the ground at a predetermined set altitude. If there is an obstacle on the ground, "ground" means the upper edge of the obstacle.

[0007] In the aerial spraying device disclosed herein, the altitude sensor can measure the altitude of the device relative to the ground surface in the direction of the device's movement, and it is preferable that the altitude of the device relative to the ground surface further away from the device can be measured as the device's speed increases. This reduces the impact of the time lag between altitude measurement and changing the length of the support column.

[0008] Details of the technology disclosed herein and further improvements are described in the following "Modes for Carrying Out the Invention". [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view of the aerial spraying device of the embodiment. [Figure 2] This is a side view of an aerial spraying device. [Figure 3] This is a diagram illustrating advanced measurement processing. [Figure 4] This is a flowchart for controlling the length of support columns while taking time lag into consideration. [Modes for carrying out the invention]

[0010] The aerial spraying device of the embodiment will be described with reference to the drawings. The aerial spraying device of the embodiment is a drone 10 that flies using a rotor. Figure 1 is a plan view of the drone 10, and Figure 2 is a side view of the drone 10. The X and Y axes of the coordinate system in the figures represent the front-to-back and lateral directions of the drone 10, respectively. The +Z direction represents the vertically upward direction.

[0011] Drone 10 is a device for spraying pesticides from the air. Drone 10 consists of a main body 11, four rotors 12, a nozzle 17, a support column 16, an altitude sensor 18, and a controller 19. Although not shown in the diagram, the main body 11 is also equipped with a tank for storing pesticides.

[0012] The drone 10 flies by generating lift with four rotors 12. Each of the four rotors 12 is positioned at one of the four corners of the main body 11. The rotors 12 are driven by motors 13. The main body 11 is equipped with a battery (not shown), and the motors 13 are powered by the battery.

[0013] A nozzle 17 for spraying pesticides is attached to the bottom of the main body 11 via a support column 16. The nozzle 17 and a tank (not shown) built into the main body 11 are connected by a tube (not shown) that passes through the inside of the support column 16. Upon command from the controller 19, pesticides from the pesticide tank are sprayed from the nozzle 17.

[0014] The support column 16 can be electrically extended downwards. Figure 2 shows the support column 16 in its shortest state. When the support column 16 is at its shortest, the nozzle 17 is positioned above the lower end of the drone's legs 14. Note that the legs 14 are not shown in the plan view of Figure 1. In Figure 2, the dotted line indicated by reference numeral 16a represents the support column when extended, and the dotted line indicated by reference numeral 17a represents the nozzle at the tip of the extended support column 16a. When the support column 16 is fully extended (support column 16a), the nozzle 17 (nozzle 17a) is positioned below the lower end of the legs 14.

[0015] The controller 19 adjusts the length of the support column 16. If pesticide is sprayed from the nozzle 17 with the support column short, the downward airflow from the rotor 12 will scatter the pesticide over a wide area. By extending the support column 16, the distance between the nozzle 17 and the rotor 12 is increased, reducing the effect of the rotor 12's airflow on pesticide spraying. Alternatively, by extending the support column 16, it becomes possible to spray pesticide from a low position while keeping the drone body 11 at a high position.

[0016] On the other hand, when spraying pesticides, it is desirable for the nozzle 17 to be close to the ground surface. The controller 19 controls the height of the nozzle 17 (height from the ground surface) by adjusting the length of the support column 16.

[0017] An altitude sensor 18 is provided on the underside of the main body 11 of the drone 10. The altitude sensor 18 measures the altitude of the drone 10 relative to the ground. The controller 19 adjusts the length of the support column 16 based on the measurement results of the altitude sensor 18 so that the altitude of the nozzle 17 maintains a predetermined set altitude.

[0018] The altitude sensor 18 emits a laser beam onto the ground and receives the reflected light. The altitude sensor 18 determines the distance to the ground from the time between the laser beam being emitted and the light being received. The altitude sensor 18 can also change the direction of the laser beam from directly below the drone 10 to the front and downward. In Figure 2, the altitude sensor indicated by reference numeral 18 has its laser beam directed directly below the main body 11. The dotted line indicated by reference numeral 18a in Figure 2 represents the altitude sensor when the laser beam direction is changed to the front and downward.

[0019] The altitude measurement process will be explained with reference to Figure 3. Note that if an obstacle Ob exists on the ground surface G, "altitude from the ground surface G" refers to the altitude from the top of the obstacle Ob.

[0020] In FIG. 3, the altitude sensor 18 tilts the irradiation direction of the laser downward from the horizontal by an angle Th in the front lower direction. As will be described in detail later, the controller 19 adjusts the irradiation angle Th of the laser according to the speed of the drone 10. Specifically, the faster the speed of the drone 10 is, the more the irradiation direction of the laser is directed downward in the front far from the drone 10.

[0021] In the example of FIG. 3, the laser of the altitude sensor 18 is directed at the upper end of the obstacle Ob. The obstacle Ob is located at a point P2 on the ground surface. The altitude sensor 18 receives the reflected light of the laser and measures the distance Ls to the obstacle Ob from the time from the irradiation of the laser to the reception of the reflected light. Further, the altitude sensor 18 calculates the altitude of the drone 10 at the point P2 (the altitude H2 from the upper end of the obstacle Ob to the drone 10) from the irradiation angle Th of the laser with respect to the horizontal and the distance Ls. Specifically, the altitude sensor 18 calculates the altitude H2 by the calculation formula of the altitude H2: H2 = Ls×sin(Th). When the irradiation direction of the laser is directly below the main body 11, the altitude H1 of the drone 10 is equal to the distance measured by the altitude sensor 18 with the laser.

[0022] The controller 19 stores the desired altitude (set altitude Hr) of the nozzle 17. The controller 19 subtracts the set altitude Hr from the altitude measured by the altitude sensor 18 (the altitude of the drone 10) to determine the target length of the support column 16. The controller 19 controls the support column 16 so that the length of the support column 16 becomes the target length.

[0023] When the laser irradiation angle Th of the altitude sensor 18 is 90 degrees, the laser is irradiated directly below the drone 10. In FIG. 3, the altitude of the drone 10 at this time is H1. The controller 19 subtracts the set altitude Hr of the nozzle 17 from the altitude H1 of the drone 10 to obtain the target length L1 of the support column 16. Then, the controller 19 adjusts the length of the support column 16 to the target length L1. By repeating this process, the drone 10 can spray the pesticide while maintaining the altitude of the nozzle 17 at the set altitude Hr.

[0024] There is a time lag between when the altitude sensor 18 measures the altitude and when the length of the support pole 16 is changed to the target length. The drone 10 can control the length of the support pole 16 taking this time lag into account. In Figure 3, the current position of the drone 10 is point P1, and it is flying in the direction of obstacle Ob at a speed V. Directly above obstacle Ob, the target length of the support pole 16 is L2. The controller 19 controls the support pole 16 so that it becomes the target length L2 when the drone 10 reaches directly above obstacle Ob. Figure 4 shows a flowchart of the support pole 16 length control taking the time lag into account. The control of the support pole 16 length will be explained with reference to Figures 3 and 4. Note that the drone 10 continues to spray pesticide until the branching decision in step S7 of Figure 4 becomes YES.

[0025] The controller 19 first obtains speed information of the drone 10 (step S2). Speed ​​information is obtained from a speed sensor (not shown) provided on the main unit 11. The controller 19 obtains the speed V of the drone 10 at point P1. In Figure 3, the drone 10 is flying from right to left.

[0026] Next, the controller 19 adjusts the tilt angle of the altitude sensor 18 (the laser irradiation angle Th relative to the horizontal) according to the speed V of the drone 10 (step S3). The faster the speed of the drone 10, the smaller the irradiation angle Th becomes, and the more the controller 19 irradiates the ground farther away in the direction of the drone 10's movement. More specifically, the controller 19 calculates the distance Loff (Loff = speed V × time lag TL) that the drone 10 travels during the time lag TL, and adjusts the irradiation angle Th so that the laser is irradiated onto the ground a distance Loff ahead of the drone 10. In the example in Figure 3, the controller 19 adjusts the laser irradiation direction of the altitude sensor 18 so that the laser is irradiated onto point P2, which is a distance Loff ahead of the drone 10's current position P1. The irradiation angle Th can be approximately calculated as Th = arcTan(L1 / Loff), where L1 is the altitude of the drone 10 at its current position (point P1).

[0027] Next, the controller 19 calculates the altitude of the drone 10 relative to point P2 from the altitude sensor 18, which is tilted forward and downward by an illumination angle Th (step S4). As mentioned earlier, the altitude of the drone 10 relative to point P2 is H2. Next, the controller 19 calculates the target length L2 of the support column 16 at point P2 by subtracting the set altitude Hr from the altitude H2 (step S5). Then the controller 19 adjusts the length of the support column 16 to the target length L2 (step S6).

[0028] As mentioned earlier, there is a time lag TL between altitude measurement and changing the length of the support column 16 to the target length H2. From the time the altitude H2 is measured at point P1 until the length of the support column 16 is changed to the target length H2, the drone 10 has advanced by Loff (=V × TL). In other words, the support column 16 is changed to the target length H2 when the drone 10 reaches directly above the obstacle Ob. In this way, the drone 10 can adjust the length of the support column 16, taking into account the time lag between altitude measurement and the change in the length of the support column 16. In other words, the drone 10 can maintain the nozzle 17 at the set altitude Hr during flight, regardless of the time lag.

[0029] The controller 19 repeats the above process until the application of pesticides is complete (steps S7: NO, S2). Once the application of pesticides is complete, the controller 19 shortens the support column 16 and terminates the process (steps S7: YES, S8). By shortening the support column 16 to its shortest length, the lower end of the nozzle 17 is higher than the lower end of the leg 14. The drone 10 can land without the nozzle 17 touching the ground.

[0030] The following points concern the technology described in the examples. The aerial spraying device in the examples was an unmanned drone 10. The technology disclosed herein can also be applied to manned aircraft (including fixed-wing and rotary-wing aircraft).

[0031] The features of the drone 10 (aerial spraying device) in this embodiment are listed below. The drone 10 comprises a main body 11, a rotor 12, a nozzle 17 for spraying chemicals, an extendable support column 16, an altitude sensor 18, and a controller 19. The rotor 12 is attached to the main body 11 and generates lift. The nozzle 17 is located below the main body 11. The support column 16 connects the main body 11 and the nozzle 17 and can extend downward from the main body 11. The support column 16 extends and retracts electrically, and the length of the support column 16 is adjusted by the controller 19.

[0032] The altitude sensor 18 measures the altitude from the ground to the main unit 11. The controller 19 controls the length of the support column 16 so that the altitude of the nozzle 17 from the ground reaches a predetermined set altitude based on the measurement value from the altitude sensor 18.

[0033] The altitude sensor 18 can measure the altitude of the main body 11 relative to the ground surface in the direction of travel of the main body 11. The altitude sensor 18 measures the altitude of the main body 11 relative to the ground surface further away from the main body 11 as the speed of the main body 11 increases. More specifically, the altitude sensor 18 is equipped with a laser irradiator that emits a laser for distance measurement, and calculates the altitude based on the distance to the ground surface measured by the laser irradiator and the laser irradiation angle (irradiation angle relative to the horizontal). The controller 19 controls the angle of the laser irradiator so that the laser is irradiated to the ground further away as the speed of the main body 11 increases. The controller 19 adjusts the laser irradiation direction of the altitude sensor 18 so that the altitude of the drone 10 relative to the ground surface in front of it is measured by multiplying the time lag TL from altitude measurement to changing the length of the support column 16 by the speed V of the drone 10.

[0034] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives itself constitutes technical usefulness. [Explanation of symbols]

[0035] 10: Drone (aerial spraying device) 11: Main body 12: Rotor 13: Motor 14: Legs 16, 16a: Support column 17, 17a: Nozzle 18, 18a: Altitude sensor 19: Controller

Claims

1. The main unit and A rotor attached to the aforementioned main body, which generates lift, A nozzle for spraying chemicals is located below the main body, The main body and the nozzle are connected by an extendable support column, An altitude sensor that measures the altitude from the ground surface to the main body, A controller that controls the support column so that the altitude of the nozzle from the ground surface becomes a predetermined set altitude based on the measurement value of the altitude sensor, An aerial spraying device equipped with [a specific feature].

2. The aerial spraying device according to claim 1, wherein the altitude sensor can measure the altitude of the main body relative to the ground surface in the direction of the main body's movement, and the altitude of the main body relative to the ground surface further away from the main body is measured as the speed of the main body increases.

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