Mobile Weeding Device

Abstract

To provide a mobile weeder capable of efficiently removing an unnecessary plant under an environment in which liquid is adhered to the unnecessary plant.SOLUTION: A aspect of the present disclosure is a mobile weeder including: a laser emitting device configured to emit laser light to a plant from above the plant; a control device configured to increase at least one of emission output and emission time of the laser light in a case where liquid is adhered to the plant to be larger than that in a case where the liquid is not adhered to the plant; and a device body holding the laser emitting device and having a movement mechanism.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a mobile weeding device.

Background Art

[0002] Weeding devices that remove unwanted plants (i.e., weeds) in agricultural fields by laser irradiation are known (see Patent Documents 1-3). In this weeding device, laser light is irradiated from above the unwanted plants to damage and kill the unwanted plants.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] In agricultural fields, for example, a liquid such as water adheres to the surface of unwanted plants. When a liquid adheres to unwanted plants in this way, there is a risk that the removal of the unwanted plants will be insufficient due to the absorption of laser light by the liquid.

[0005] One aspect of the present disclosure aims to provide a mobile weeding device that can efficiently remove unwanted plants in an environment where a liquid adheres to the unwanted plants.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a mobile weeding device including a laser irradiator configured to irradiate laser light toward a plant from above the plant, a control device configured to increase at least one of an irradiation output and an irradiation time of the laser light when a liquid adheres to the plant as compared to when no liquid adheres to the plant, and a device body that holds the laser irradiator and has a moving mechanism.

[0007] According to such a configuration, when a liquid adheres to an unwanted plant, the unwanted plant can be removed by increasing the irradiation output or the irradiation time of the laser light. Also, when no liquid adheres to the unwanted plant, the irradiation output or the irradiation time of the laser light can be suppressed. Therefore, it is possible to efficiently remove unwanted plants while suppressing an increase in battery capacity, an increase in power consumption, and excessive irradiation of laser light.

[0008] One aspect of the present disclosure may further include a camera that is held by the device body and is configured to acquire an image of the plant taken from above. The control device may determine the liquid adhesion state of the plant based on the image. According to such a configuration, the liquid adhesion state can be grasped relatively easily, and the adhesion location of the liquid on the unwanted plant can also be determined.

[0009] One aspect of the present disclosure may further include a sensor that is held by the device body and is configured to perform irradiation of a wave to the plant and detection of the wave reflected from the plant. The control device may determine the liquid adhesion state of the plant based on the detection signal of the sensor. Also according to such a configuration, the liquid adhesion state can be grasped relatively easily, and the adhesion location of the liquid on the unwanted plant can also be determined.

[0010] In one aspect of the present disclosure, the wavelength of the laser light may be 400 nm or more and 550 nm or less. According to such a configuration, it becomes difficult for the laser light to be absorbed by the liquid. Therefore, the removal efficiency of unwanted plants can be increased.

[0011] One aspect of the present disclosure may further include a water injector configured to inject water into the irradiation area of the laser beam. According to such a configuration, generation of smoke due to irradiation of the laser beam can be suppressed. Further, even when the injected water adheres to the unwanted plants before removal, the unwanted plants can be efficiently removed by adjusting the laser beam by the control device.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

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Figure 7

Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments to which the present disclosure is applied will be described with reference to the drawings. [1. First Embodiment] [1-1. Configuration] The mobile weeding device 1 shown in FIG. 1 is a device for removing unwanted plants P2 (that is, weeds) generated around the agricultural crop P1 in the farmland. The mobile weeding device 1 includes a device body 2, a laser irradiator 3, a camera 4, a lighting 5, a water injector 6, a monitoring sensor 7, and a control device 9.

[0014] <Device Body> The apparatus main body 2 is a housing that holds a laser irradiator 3, a camera 4, a lighting device 5, a water injector 6, a monitoring sensor 7, and a control device 9. The apparatus main body 2 also has a moving mechanism.

[0015] The moving mechanism of the present embodiment is constituted by a plurality of wheels 21. The apparatus main body 2 is configured to travel on farmland by the plurality of wheels 21. The moving mechanism may be an electric type that rotates the wheels 21 by a motor, or a manual type that moves by an operator pushing or pulling the apparatus main body 2. Further, the apparatus main body 2 may be provided with one or more electric crawlers instead of the wheels 21 as the moving mechanism.

[0016] As shown in FIG. 2, the mobile weeding device 1 travels along the longitudinal direction of a plurality of ridges F. The mobile weeding device 1 performs laser irradiation and water injection on the unwanted plants P2 for each of the plurality of ridges F.

[0017] <Laser irradiator> The laser irradiator 3 shown in FIG. 1 is configured to irradiate laser light L toward the unwanted plant P2 from above the unwanted plant P2 identified by the control device 9. The laser irradiator 3 may be configured to irradiate the laser light L from above the unwanted plant P2 by changing the direction of the laser light L using an optical element such as a mirror.

[0018] The laser irradiator 3 causes the unwanted plant P2 to wither by damaging (specifically, burning) the unwanted plant P2 with the laser light L. The laser light L is irradiated onto the growth point or the root of the unwanted plant P2. The growth point and the root of the unwanted plant P2 are determined by the control device 9 based on the image acquired by the camera 4.

[0019] As the laser irradiator 3, a known laser irradiation device having a battery, an oscillator, and a reflection control unit (for example, a galvanometer scanner, MEMS, etc.) can be used. The wavelength of the laser light of the laser irradiator 3 is 400 nm or more and 550 nm or less.

[0020] The laser irradiator 3 is configured to be able to change the irradiation direction, irradiation output, and irradiation time of the laser beam L. The irradiation output is changed by a signal (for example, an analog input voltage) output from the control device 9 to the oscillator.

[0021] The laser irradiator 3 may perform laser irradiation while the apparatus main body 2 is moving, or may perform laser irradiation while the apparatus main body 2 is stopped. The laser irradiator 3 sequentially performs laser irradiation on a plurality of unwanted plants P2 identified by the control device 9.

[0022] <Camera> The camera 4 is configured to acquire an image of a farmland in which at least one crop P1 and at least one unwanted plant P2 are mixed, taken from above.

[0023] The image acquired by the camera 4 includes at least one crop P1, at least one unwanted plant P2, and other objects (for example, structures such as fences, obstacles such as stones, etc.). The imaging range of the camera 4 changes as the apparatus main body 2 moves.

[0024] <Illumination> The illumination 5 is configured to illuminate the imaging area of the camera 4. That is, the illumination 5 shines light on at least one unwanted plant P2.

[0025] <Water injector> The water injector 6 is configured to inject fire-extinguishing water into the irradiation area of the laser beam L from above.

[0026] Specifically, the water injector 6 injects water toward the unwanted plant P2 after the laser beam L has been irradiated. The coordinates and range where the water injector 6 injects water are set by the control device 9. Water is supplied to the water injector 6 from, for example, a water tank (not shown) installed in the apparatus main body 2.

[0027] <Monitoring sensor> The monitoring sensor 7 is a known device that detects temperature and the presence or absence of smoke in the irradiation area of the laser beam.

[0028] <Control device> The control device 9 mainly controls the laser irradiator 3 and the water injector 6. The control device 9 is composed of, for example, a computer including a processor, a storage medium such as a RAM and a ROM, a communication unit, and an input / output unit. As shown in FIG. 3, the control device 9 has an image processing unit 91, a laser control unit 92, an injection control unit 93, and a database 94.

[0029] The image processing unit 91 is configured to identify unnecessary plants P2 from the images captured by the camera 4. The image processing unit 91 identifies unnecessary plants P2 using AI (artificial intelligence) constructed by known statistical methods.

[0030] Examples of statistical methods include supervised machine learning, multivariate analysis, etc. In supervised machine learning, a discriminant formula (i.e., a classifier) is constructed by analyzing images of plants with a large number of labels (i.e., teacher data) using a machine learning circuit.

[0031] After identifying the unnecessary plants P2, the image processing unit 91 is further configured to determine the liquid adhesion status of the unnecessary plants P2 based on the images captured by the camera 4. Specifically, the image processing unit 91 determines "the presence or absence of liquid at the irradiation site of the laser light on the unnecessary plants P2".

[0032] As shown in FIG. 4, liquids such as water, pesticides, and liquid fertilizers can adhere to the unnecessary plants P2 as droplets W1. In addition, there are also liquid puddles W2 on the ridges F (i.e., the ground) where the unnecessary plants P2 are present.

[0033] As shown in FIG. 5A, first, in the image S including the unnecessary plants P2 and the droplets W1 captured by the camera 4, the image processing unit 91 refers to a large number of plant image data (i.e., teaching data) stored in the database 94 to recognize the leaf shape, number, position, etc. of the unnecessary plants P2.

[0034] Next, as shown in FIG. 5B, the image processing unit 91 sets a target area R including the growth point or the root of the unwanted plant P2 identified by AI for the unwanted plant P2. The growth point is a site mainly including an active tissue of cell division at the tip of the plant stem and can be specified according to the type of the plant. After setting the target area R, the image processing unit 91 determines whether or not the droplet W1 exists in the target area R.

[0035] Specifically, the image processing unit 91 refers to the image data of a large number of droplets stored in the database 94 to determine whether the droplet W1 exists. For example, when the target area R includes an image area that matches or is similar to the image of the droplet in the database 94, the image processing unit 91 determines that the droplet W1 exists (that is, the target area R is wet). Note that the image processing unit 91 may set the target area R after determining the presence or absence of the droplet W1 for the entire unwanted plant P2.

[0036] The laser control unit 92 shown in FIG. 3 instructs the laser irradiator 3 to irradiate the laser light with respect to the coordinates of the unwanted plant P2 identified by the image processing unit 91. Specifically, the laser control unit 92 instructs the laser irradiator 3 to irradiate the laser light to the target area R set by the image processing unit 91.

[0037] In addition, the laser control unit 92 determines the irradiation amount of the laser light (that is, the irradiation energy to the unwanted plant P2) according to the liquid adhesion situation in the unwanted plant P2. The irradiation amount of the laser light is proportional to the irradiation output and the irradiation time of the laser light.

[0038] The laser control unit 92 makes the irradiation amount of the laser light when it is determined that the liquid exists in the target area R (that is, the liquid adheres to the unwanted plant P2) larger than the irradiation amount of the laser light when it is determined that the liquid does not exist in the target area R (that is, the liquid does not adhere to the unwanted plant P2).

[0039] The irradiation amount of the laser light is adjusted by changing at least one of the irradiation output and the irradiation time of the laser light. In the adjustment to increase the irradiation amount of the laser light, either the irradiation output is increased without changing the irradiation time, the irradiation time is increased without changing the irradiation output, or both the irradiation output and the irradiation time are increased.

[0040] Among these control patterns, by adjusting only the irradiation output of the laser light or only the irradiation time of the laser light, complex control is not required and the irradiation amount of the laser light can be adjusted relatively easily.

[0041] The irradiation output of the laser light is adjusted by the input to the laser irradiator 3 as described above. The irradiation time of the laser light is adjusted, for example, by the number of revolutions and / or the moving speed of the irradiation point of the laser light. The irradiation point of the laser light moves so as to revolve around the growth point or the root of the unwanted plant P2.

[0042] The laser control unit 92 inputs the irradiation coordinates, irradiation output, irradiation time, irradiation locus, etc. adjusted as described above to the laser irradiator 3. The laser irradiator 3 irradiates the unwanted plant P2 with laser light along the irradiation locus at the irradiation output and irradiation time instructed by the laser control unit 92.

[0043] The injection control unit 93 instructs the water injector 6 to inject water into the area where the monitoring sensor 7 detects high temperature or the area where smoke is detected. Further, the injection control unit 93 may instruct the water injector 6 to inject water onto the unwanted plant P2 irradiated with laser light after the laser light irradiation of the laser irradiator 3 onto the unwanted plant P2 regardless of the detection result of the monitoring sensor 7.

[0044] The control device 9 may be configured to output to the monitor installed in the device main body 2 the identification result of the unwanted plant P2 by the image processing unit 91, the detection results of temperature and smoke by the monitoring sensor 7, etc.

[0045] <Processing of the control device> Next, an example of the processes executed by the image processing unit 91 and the laser control unit 92 of the control device 9 will be described with reference to the flowchart of FIG. 6.

[0046] In this process, first, the image processing unit 91 acquires the image captured by the camera 4 (step S110). Next, the image processing unit 91 determines whether the plant included in the acquired image is an unwanted plant (step S120).

[0047] If the plant in the image is not an unwanted plant (S120: NO), the control device 9 ends the process. On the other hand, if the plant in the image is an unwanted plant (S120: YES), the image processing unit 91 sets a target area (step S130).

[0048] After setting the target area, the image processing unit 91 determines whether there is liquid in the target area (step S140). If there is no liquid (S140: NO), the laser control unit 92 irradiates the target area of the unwanted plant with laser light for the first irradiation time T1 (step S150).

[0049] On the other hand, if there is liquid (S140: YES), the laser control unit 92 irradiates the target area of the unwanted plant with laser light for the second irradiation time T2, which is longer than the first irradiation time T1 (step S160).

[0050] Note that the laser control unit 92 may irradiate the laser light with the first irradiation output when there is no liquid (S140: NO), and irradiate the laser light with the second irradiation output, which is larger than the first irradiation output, when there is liquid (S140: YES).

[0051] [1-2. Effects] According to the embodiment described in detail above, the following effects can be obtained. (1a) When liquid adheres to unwanted plants, the unwanted plants can be removed by increasing the irradiation output or irradiation time of the laser beam. Also, when no liquid adheres to the unwanted plants, the irradiation output or irradiation time of the laser beam can be suppressed. Therefore, while suppressing an increase in battery capacity, an increase in power consumption, and excessive irradiation of the laser beam, the unwanted plants can be efficiently removed.

[0052] (1b) Based on the image acquired by the camera 4, the control device 9 determines the liquid adhesion state of the unwanted plant P2, so that the liquid adhesion state can be grasped relatively easily and the adhesion location of the liquid on the unwanted plant can also be determined.

[0053] (1c) When the wavelength of the laser beam is 400 nm or more and 550 nm or less, the laser beam is less likely to be absorbed by the liquid. Therefore, the removal efficiency of the unwanted plants can be increased.

[0054] (1d) The water injector 6 can suppress the generation of smoke due to the irradiation of the laser beam. Also, even when the injected water adheres to the unwanted plants before removal, the control device 9 can efficiently remove these unwanted plants by adjusting the laser beam.

[0055] [2. Second Embodiment] [2-1. Configuration] The mobile weeding device 11 shown in FIG. 7 includes a device main body 2, a laser irradiator 3, a camera 4, a lighting 5, a water injector 6, a monitoring sensor 7, a liquid sensor 8, and a control device 19.

[0056] The device main body 2, the laser irradiator 3, the camera 4, the lighting 5, the water injector 6, and the monitoring sensor 7 of the mobile weeding device 11 are the same as those of the mobile weeding device 1 in FIG. 1. The mobile weeding device 11 of the present embodiment adds a liquid sensor 8 to the mobile weeding device 1 of the first embodiment and partially changes the functions of the control device 9 of the first embodiment.

[0057] <Sensor> The liquid sensor 8 is held in the apparatus main body 2 together with the camera 4 and the like. The liquid sensor 8 is configured to irradiate waves to the unnecessary plant P2 and detect the reflected waves.

[0058] Examples of the waves used by the liquid sensor 8 include sound waves, electromagnetic waves (i.e., light waves and radio waves), and the like. As the liquid sensor 8, for example, a commercially available distance sensor (e.g., LiDAR), a sonar, or the like can be used.

[0059] When the wave irradiated by the liquid sensor 8 collides with a plant and when it collides with a liquid, the reflection changes. Therefore, the presence of the liquid in the irradiation area of the laser light can be confirmed by analyzing the detection signal of the liquid sensor 8.

[0060] <Control device> The control device 19 is obtained by modifying the control device 9 of the first embodiment to determine the liquid adhesion state of the unnecessary plant P2 based on the detection signal of the liquid sensor 8 instead of the image acquired by the camera 4.

[0061] Specifically, when it is determined by analyzing the detection signal that liquid exists in the target area of the unnecessary plant, the control device 19 increases the irradiation amount of the laser light compared to the irradiation amount of the laser light when it is determined that no liquid exists in the target area.

[0062] The irradiation amount of the laser light is adjusted by changing at least one of the irradiation output and the irradiation time of the laser light. In the adjustment to increase the irradiation amount of the laser light, any one of the following adjustments is made: increasing only the irradiation output without changing the irradiation time, increasing only the irradiation time without changing the irradiation output, or increasing both the irradiation output and the irradiation time.

[0063] [2-2. Effects] According to the embodiment described in detail above, the following effects can be obtained. (2a) Based on the detection signal of the liquid sensor 8, the control device 19 determines the liquid adhesion situation, enabling the relatively easy grasp of the liquid adhesion situation and also the determination of the liquid adhesion location on unwanted plants.

[0064] [3. Other Embodiments] As described above, the embodiments of the present disclosure have been explained. Needless to say, the present disclosure is not limited to the above embodiments and can take various forms.

[0065] (3a) In the mobile weeding device of the above embodiment, the control device does not necessarily have to be held by the device main body. For example, the control device may be installed on the farmland or a facility away from the farmland and may be configured to perform wireless communication with a camera, a laser irradiator, etc.

[0066] (3b) The mobile weeding device of the above embodiment does not necessarily have to be equipped with lighting. If an image capable of recognizing unwanted plants can be obtained by taking in external light and adjusting the brightness of the camera, the lighting can be omitted.

[0067] (3c) In the mobile weeding device of the above embodiment, the moving form of the device main body is not limited to traveling. The mobile weeding device may move, for example, by flying.

[0068] (3d) The functions of one component in the above embodiment may be distributed among a plurality of components, or the functions of a plurality of components may be integrated into one component. Also, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added to, replaced with, etc. the configuration of other above embodiments. Note that all aspects included in the technical idea specified from the language described in the claims are embodiments of the present disclosure.

Explanation of Reference Numerals

[0069] 1... Mobile weeding device, 2... Device main body, 3... Laser irradiator, 4... Camera, 5... Lighting, 6... Water injector, 7... Monitoring sensor, 8... Liquid sensor, 9... Control device, 11... Mobile weeding device, 19... Control device, 21... Wheels, 91... Image processing unit, 92... Laser control unit, 93... Injection control unit, 94... Database.

Claims

1. A laser irradiator configured to irradiate a laser beam toward the plant from above the plant; A control device configured to make at least one of the irradiation output and irradiation time of the laser beam greater when liquid is adhering to the plant than when no liquid is adhering to the plant; A device body that holds the laser irradiator and has a moving mechanism; A mobile weeding device comprising the above.

2. The mobile weeding device according to Claim 1, further comprising a camera held by the device body and configured to acquire an image of the plant taken from above, wherein the control device determines the liquid adhesion state of the plant based on the image.

3. The mobile weeding device according to Claim 1, further comprising a sensor held by the device body and configured to perform irradiation of waves on the plant and detection of the reflected waves, wherein the control device determines the liquid adhesion state of the plant based on the detection signal of the sensor.

4. The mobile weeding device according to any one of Claims 1 to 3, wherein the wavelength of the laser beam is 400 nm or more and 550 nm or less.

5. The mobile weeding device according to any one of Claims 1 to 3, further comprising a water injector configured to inject water into the irradiation area of the laser beam. ​ ​ ​ ​

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