Control device, control method, and program

Abstract

The present technology relates to a control device, a control method, and a program that make it possible to easily perform appropriate irrigation. As a control signal for controlling the irrigation, a control signal having a variable pulse width and / or pulse interval is generated. The present technology can be applied, for example, to control of irrigation by an irrigation device in a field or the like.

Description

Control device, control method, and program

[0001] The present technology relates to a control device, a control method, and a program, and in particular to a control device, a control method, and a program that enable, for example, appropriate irrigation to be easily performed.

[0002] For example, Patent Document 1 proposes an irrigation device that accumulates the amount of solar radiation, and when the accumulated value of the amount of solar radiation reaches a set accumulated value, temporarily opens an electromagnetic valve to irrigate a fixed amount of water.

[0003] Patent No. 6612503

[0004] When the integrated value of the amount of solar radiation reaches a set integrated value, it may be difficult to perform appropriate irrigation by irrigating at a constant amount of water.

[0005] The present technology has been developed in light of such circumstances, and makes it possible to easily perform appropriate irrigation.

[0006] The control device or program of the present technology is a control device that has a generation unit that generates a control signal with a variable pulse width and / or pulse interval as a control signal for controlling irrigation, or a program for causing a computer to function as such a control device.

[0007] The control method of the present technology is a control method that includes generating a control signal having a variable pulse width and / or a variable pulse interval as a control signal for controlling irrigation.

[0008] In the present technology, a control signal with a variable pulse width and / or pulse interval is generated as a control signal for controlling irrigation.

[0009] The control device may be an independent device or an internal block constituting one device.

[0010] The program can be provided by transmitting it via a transmission medium or by recording it on a recording medium.

[0011] 1 is a block diagram showing an example of the configuration of an embodiment of an environmental control system to which the present technology is applied. FIG. 2 is a diagram showing an example of the configuration of an irrigation control system to which the environmental control system 10 is applied. FIG. 3 is a diagram showing an example of a control signal for controlling irrigation generated by the control device 12. FIG. 4 is a diagram showing another example of a control signal for controlling irrigation generated by the control device 12. FIG. 5 is a diagram explaining an overview of generation of a control signal by the control device 12. FIG. 6 is a diagram showing a first example of a target soil moisture profile. FIG. 7 is a diagram showing a second example of a target soil moisture profile. FIG. 8 is a diagram showing a third example of a target soil moisture profile. FIG. 9 is a diagram showing an example of a target soil moisture profile that defines a soil moisture curve according to the condition of a target field. FIG. 10 is a diagram showing a fourth example of a target soil moisture profile. FIG. 11 is a diagram showing a schematic example of a target soil moisture profile for one location of soil. FIG. 12 is a diagram showing a schematic example of a target soil moisture profile for each of a plurality of locations of soil. FIG. 13 is a diagram showing another example of a target soil moisture profile for each of a plurality of locations of soil. FIG. 14 is a diagram explaining an example of generation of a target soil moisture profile by the input device 11. FIG. 15 is a block diagram showing an example of the configuration of the control device 12. FIG. 16 is a diagram explaining an example of a mathematical model used for simulating soil moisture content by the simulator 112. FIG. 17 is a diagram explaining an overview of an example of irrigation control by the control device 12. 1 is a diagram illustrating the updating of physical parameters of the simulator 112 that is performed after irrigation is performed in accordance with one pulse as a control signal. FIG. 2 is a flowchart illustrating an example of processing for controlling irrigation by the control device 12. FIG. 3 is a flowchart illustrating an example of processing for initializing physical parameters, in which values ​​that match the conditions of a target field are set as initial values ​​of the physical parameters. FIG. 4 is a diagram illustrating an example of generating a control signal based on a weather forecast. FIG. 5 is a flowchart illustrating another example of processing for controlling irrigation by the control device 12. FIG. 6 is a diagram illustrating examples of time series of observed soil moisture content when a target soil moisture profile and a target water stress profile are adopted as the target profile. FIG. 7 is a block diagram illustrating an example of the configuration of an embodiment of a computer to which the present technology is applied.

[0012] <One embodiment of an environmental control system to which the present technology is applied>

[0013] FIG. 1 is a block diagram showing an example of the configuration of an embodiment of an environmental control system to which the present technology is applied.

[0014] In FIG. 1, an environmental control system 10 includes an input device 11, a control device 12, a group of sensors 13, and a group of environmental control devices 14.

[0015] The input device 11 is configured by, for example, a smartphone or a PC (personal computer), and acquires a target profile in response to a user's operation and transmits it to the control device 12 .

[0016] The target profile is a profile of target environmental information (also referred to as target environmental information). Environmental information is information about the environment, and includes not only physical quantities that can be directly sensed, such as temperature, humidity, soil moisture content, saturation deficit, and carbon dioxide content, but also information on which the physical quantities are factors or indicators, such as information (stress values) that indicate the degree of environmental stress, such as water stress, that a plant is subjected to. For example, a physical quantity that serves as an indicator of water stress is tree water tension (water potential value within the tree body).

[0017] The control device 12 generates a control signal for controlling the group of environmental control devices 14 and supplies (transmits) the control signal to the group of environmental control devices 14, thereby controlling the environment of a target location, such as a farm field. A farm field as a target location for environmental control is also referred to as a target farm field. The target farm field may be an indoor farm field such as a greenhouse, or may be an outdoor farm field.

[0018] For example, the control device 12 generates a control signal for controlling irrigation as a control signal for controlling the soil moisture content, etc. of the target field, and supplies the generated control signal to the environmental control device group 14. In addition, the control device 12 generates other control signals for controlling various environmental items (temperature, humidity, amount of solar radiation, wind speed, wind direction, environmental stress value, etc.) of the target field other than the soil moisture content, and supplies the generated control signals to the environmental control device group 14.

[0019] For example, the control device 12 generates a control signal based on the target profile from the input device 11. Various types of sensor data are supplied to the control device 12 from the sensor group 13. The control device 12 generates a control signal to control the environmental control device group 14 in order to control (adjust) the environment of the target field so that the observed values ​​of each environmental item obtained from the sensor data from the sensor group 13 match the target profile (target environment information defined in the target profile).

[0020] The sensor group 13 includes one or more sensors that sense various physical quantities in the target field and is installed at appropriate locations in the target field. For example, the sensor group 13 includes a stress sensor 31, a weather sensor 32, a soil sensor 33, etc.

[0021] The stress sensor 31 senses physical quantities that are factors or indicators of various environmental stresses, such as water stress, that plants in the target field are subjected to, and supplies sensor data representing these physical quantities to the control device 12. As the stress sensor 31, for example, a dendrometer, a sap flow sensor, a camera, etc. can be used. The growth rate sensed by the dendrometer, the sap flow rate sensed by the sap flow sensor, and the degree of withering of the plant recognized from an image of the plant obtained by sensing light with a camera can be said to be factors or indicators of the environmental stress that the plant is subjected to, and can be used as an environmental stress value or an element for estimating the environmental stress value.

[0022] The weather sensor 32 senses physical quantities related to the weather and supplies sensor data representing the physical quantities to the control device 12. As the weather sensor 32, for example, a sensor that senses temperature, humidity, solar radiation, wind speed, wind direction, etc. can be used.

[0023] The soil sensor 33 senses physical quantities related to the soil and supplies sensor data representing the physical quantities to the control device 12. As the soil sensor 33, a moisture sensor that senses soil moisture, an EC sensor that senses EC (electric conductivity), a soil temperature sensor that senses soil temperature, etc. can be used.

[0024] It is possible to install not only one but multiple sensors of the various types employed as the stress sensor 31, weather sensor 32, and soil sensor 33. For example, a moisture sensor that senses soil moisture can be installed not only at one location in the soil of the field, but also at multiple locations, for example, at multiple locations at different depths.

[0025] The environmental control device group 14 includes one or more environmental control devices that control (adjust) various aspects of the environment of the target field, and is installed at appropriate locations in the target field. Each environmental control device included in the environmental control device group 14 operates (is controlled) in accordance with a control signal from the control device 12.

[0026] In FIG. 1, the environmental control device group 14 includes, as environmental control devices, an irrigation device 41, an electric curtain 42, an air conditioner 43, a humidifier 44, and a blower 45, etc.

[0027] The irrigation device 41 irrigates in accordance with a control signal from the control device 12, and controls (adjusts) the soil moisture content, humidity, etc. of the target field. The electric curtain 42 opens and closes in accordance with a control signal from the control device 12, and controls the amount of solar radiation, etc. of the target field. The air conditioner 43 controls the temperature of the target field in accordance with a control signal from the control device 12. The humidifier 44 humidifies in accordance with a control signal from the control device 12, and controls the humidity, etc. of the target field. The fan 45 controls the wind in the target field in accordance with a control signal from the control device 12.

[0028] In the environmental control system 10 configured as described above, the control device 12 generates a control signal for controlling the group of environmental control devices 14 to control (adjust) the environment of the target field so that the observed values ​​of each environmental item obtained from the sensor data from the group of sensors 13 match the target profile from the input device 11. The control device 12 then supplies the control signal to the group of environmental control devices 14.

[0029] Each environmental control device in the group of environmental control devices 14 operates in accordance with a control signal from the control device 12, thereby controlling the environment of the target farm field.

[0030] The sensor group 13 senses various physical quantities of the target field after the environment has been controlled, and supplies the sensor data to the control device 12 .

[0031] The control device 12 again generates a control signal to control the environment of the target field so that the observed values ​​of each environmental item obtained from the sensor data from the sensor group 13 match the target profile from the input device 11, and the same process is repeated thereafter.

[0032] The control device 12 can access a weather database 22, which stores weather forecasts including forecasts of wind speed, wind direction, humidity, air temperature, and the probability of precipitation, via a network 21 such as the Internet, to obtain the weather forecast for the target field. The control device 12 can then generate a control signal based on the weather forecast (taking the weather forecast into consideration). For example, if the weather forecast predicts rain, the control device 12 can generate a control signal for controlling irrigation that reduces the amount of irrigation water compared to when the weather forecast predicts sunny weather.

[0033] Hereinafter, the present technology will be described using as an example a case where the environmental control system 10 in FIG. 1 is used as an irrigation control system that controls irrigation by an irrigation device 41.

[0034] <Irrigation control system>

[0035] FIG. 2 is a diagram showing an example of the configuration of an irrigation control system to which the environmental control system 10 is applied.

[0036] In the figure, parts corresponding to those in FIG. 1 are given the same reference numerals, and the description thereof will be omitted below as appropriate.

[0037] In FIG. 2 , the irrigation control system 60 includes an input device 11 through a sensor group 13 and an irrigation device 41 .

[0038] The irrigation device 41 includes a support 71, a pipe 72, a communication cable 73, a water pipe (tube) 74, an emitter unit 75, a water pump 78, and a water tank 79, and is installed in the target field.

[0039] Two posts 71 are fixed vertically to the soil at a predetermined distance apart on one short side of the target field, which is approximately rectangular in plan view, and two posts 71 are fixed vertically to the soil on the other short side so as to face the posts 71 on one short side.

[0040] The pipe 72 is fixed in a U-shape from one support 71 on one short side to the opposing support 71 on the other short side, to another support 71 on the other short side, and to the other support 71 on the other short side, at a predetermined height on the support 71. A plurality of emitter units 75 are fixed to the pipe 72.

[0041] The communication cable 73 is a cable that transmits an electrical signal as a control signal output (supplied) by the control device 12, and is connected to the control device 12. Furthermore, the communication cable 73 passes through the inside of the pipe 72 and is connected to an emitter unit 75 fixed to the pipe 72.

[0042] The control signal output by the control device 12 is transmitted (supplied) to the emitter unit 75 via a communication cable 73 passing through the pipe 72, thereby controlling the emitter unit 75 and, ultimately, irrigation.

[0043] The water pipe 74 is connected to a water pump 78 , and further passes through the inside of the pipe 72 and is connected to an emitter unit 75 fixed to the pipe 72 .

[0044] The water discharged by the water pump 78 is sent to the emitter unit 75 via the water pipe 74 that runs through the pipe 72, and thereby the water is emitted (sprinkled) from the emitter unit 75.

[0045] The emitter unit 75 includes an electric valve 76 and an irrigation emitter 77 .

[0046] A communication cable 73 and a water pipe 74 that pass through the pipe 72 are connected to the motorized valve 76. The motorized valve 76 opens and closes in accordance with a control signal from the control device 12 that is transmitted via the communication cable 73. When the motorized valve 76 is in the open position, it supplies water from a water supply pump 78 that is sent via the water pipe 74 to the irrigation emitter 77.

[0047] The irrigation emitter 77 outputs water from the electric valve 76 .

[0048] The control device 12 transmits a control signal for controlling (opening and closing) the electric valve 76 to the electric valve 76 via the communication cable 73, thereby controlling irrigation, i.e., the output of water from the irrigation emitter 77.

[0049] The water pump 78 sends water stored in a water tank 79 through the water pipe 74 to the electric valve 76 .

[0050] The water tank 79 stores water.

[0051] The configuration of the irrigation device 41 is not limited to the configuration shown in FIG. 2 . For example, the irrigation device 41 may be configured such that a cylindrical, elongated tube through which water flows is laid over the soil, suspended in midair by being supported on a pole, or buried in the soil. The irrigation device 41 may also be configured such that irrigation emitters (drippers) are provided at regular or irregular intervals on the side of the cylindrical tube. In this case, a valve is provided at one end of the tube on the upstream side (the water source side), and the opening and closing of the valve can be controlled by a control signal. When the valve is opened, water is sent into the tube, and water drips from each irrigation emitter provided on the side of the tube. Furthermore, although the emitter unit 75 having an electric valve 76 is shown in this example, other types, such as a sprinkler type or a mist nozzle type, may also be used.

[0052] <Control signal>

[0053] FIG. 3 is a diagram showing an example of a control signal for controlling irrigation, which is generated by the control device 12.

[0054] In FIG. 3, the horizontal axis represents time, and the vertical axis represents the level of the control signal.

[0055] The control device 12 generates, for example, a pulse signal as a control signal for controlling irrigation. For example, when the pulse signal as the control signal is at H (high) level, the motor-operated valve 76 is in an open (ON) state (opens), and when the pulse signal as the control signal is at L (low) level, the motor-operated valve 76 is in a closed (OFF) state (closes).

[0056] Fig. 3A shows an example of a control signal with a fixed (constant) pulse width and pulse interval, and Fig. 3B shows an example of a control signal with a variable pulse width and / or pulse interval.

[0057] Generally, the irrigation speed is a predetermined fixed value, and it is difficult to variably control the irrigation speed of the irrigation emitter 77. When the irrigation speed is a fixed value, the amount of irrigation is determined by the time the electric valve 76 is open, i.e., the time the irrigation emitter 77 is outputting water.

[0058] When a control signal with a fixed pulse width and pulse interval, such as that shown in FIG. 3A, is used as the control signal, it is difficult to precisely control the amount of irrigation water, and therefore the amount of soil moisture.

[0059] On the other hand, when a control signal with a variable pulse width and / or pulse interval, such as that shown in B of Fig. 3, is used as the control signal, the irrigation amount, and therefore the soil moisture content, can be finely controlled. Therefore, by using a control signal with a variable pulse width and / or pulse interval, it is possible to easily perform appropriate irrigation, such as irrigation according to a target profile of a target soil moisture content (also called a target soil moisture profile).

[0060] Therefore, the control signal generated by the control device 12 can be a control signal (pulse signal) with a variable pulse width and / or pulse interval. A control signal with a variable pulse width or pulse interval allows for more precise control of the irrigation amount than a control signal with a fixed pulse width and pulse interval. Furthermore, a control signal with a variable pulse width and pulse interval allows for even more precise control of the irrigation amount.

[0061] FIG. 4 is a diagram showing another example of a control signal for controlling irrigation, which is generated by the control device 12. In FIG.

[0062] In FIG. 4, the horizontal axis represents time, and the vertical axis represents the level of the control signal.

[0063] The control device 12 can generate a plurality of control signals for controlling irrigation of a plurality of systems. For example, the control device 12 can generate a plurality of control signals for controlling irrigation by a plurality of irrigation devices each having a different irrigation speed.

[0064] Figure 4 shows two examples of control signals for controlling two systems of irrigation. That is, Figure 4 shows a control signal with a variable pulse width and / or pulse interval as a control signal for a first system that controls irrigation of a first system (irrigation of a certain irrigation device). Figure 4 also shows a control signal with a variable pulse width and / or pulse interval as a control signal for a second system that controls irrigation of a second system (irrigation of another irrigation device).

[0065] FIG. 5 is a diagram for explaining an outline of generation of a control signal by the control device 12. In FIG.

[0066] The input device 11 acquires a target profile in response to a user's operation and transmits it to the control device 12. The target profile may be a target profile of an environmental item that is affected by irrigation. For example, the target profile may be a target profile of a target soil moisture content (target soil moisture profile) or a target profile of a target water stress value for a plant (also referred to as a target water stress profile). Hereinafter, unless otherwise specified, the target soil moisture profile will be used as the target profile.

[0067] The control device 12 generates a control signal whose pulse width and / or pulse interval is adjusted based on the target soil moisture profile from the input device 11 .

[0068] That is, the control device 12 generates a control signal with adjusted pulse width and / or pulse interval so that the observed soil moisture value (also called observed soil moisture value) obtained from sensor data from the moisture sensor of the sensor group 13 matches the target soil moisture profile from the input device 11.

[0069] The control device 12 supplies a control signal to the irrigation device 41 .

[0070] The irrigation device 41 opens and closes an electric valve 76 (FIG. 2) in accordance with a control signal from the control device 12, thereby performing irrigation in accordance with the control signal.

[0071] The moisture sensors of the sensor group 13 are installed in the soil of the target field. The moisture sensors sense the amount of soil moisture, and sensor data representing the soil moisture amount is supplied to the control device 12.

[0072] The control device 12 obtains the observed soil moisture content after irrigation according to the control signal from the sensor data from the moisture sensor. The control device 12 generates a control signal with an adjusted pulse width and / or pulse interval so that the observed soil moisture content matches the target soil moisture profile, and similar processes are repeated thereafter.

[0073] For example, a plurality of target soil moisture profiles each defining a default curve can be prepared as a time-series curve (data sequence) of the target soil moisture content in the input device 11. In this case, the input device 11 allows the user to select a target soil moisture profile to be used in the control device 12 from the plurality of target soil moisture profiles each defining a default curve in response to an operation by the user.

[0074] Furthermore, the input device 11 can generate a soil moisture curve in response to user operations, and generate a target soil moisture profile that defines the soil moisture curve.

[0075] Furthermore, the target soil moisture profile can be sold on the network 21. For example, a server (not shown) on the network 21 can sell a target soil moisture profile that defines a soil moisture curve sensed in a field owned by an experienced farmer or a soil moisture curve sensed in a field where crops exceeding a predetermined standard in quality and / or yield have been harvested. In this case, the input device 11, in response to a user's operation, can perform a process for purchasing the target soil moisture profile sold by the server and download the target soil moisture profile.

[0076] <Target soil moisture profile>

[0077] FIG. 6 is a diagram showing a first example of a target soil moisture profile.

[0078] 6, the vertical axis represents soil moisture content and the horizontal axis represents time, as well as the figures showing target soil moisture profiles to be described later.

[0079] The target soil moisture profile is a description that defines the target soil moisture content, and as the description, for example, a curve of the target soil moisture content can be adopted.

[0080] In the target soil moisture profile of FIG. 6, a soil moisture curve having a substantially triangular wave shape that fluctuates between a lower reference value RL and an upper reference value RH (>RL) is defined.

[0081] The upper reference value RH and the lower reference value RL are values ​​that serve as a guideline (level) for soil moisture content. For example, the upper and lower limits of the range of values ​​appropriate for the growth of the plant species to be irrigated can be adopted as the soil moisture content during the day (daytime).

[0082] According to the control signal generated based on the target soil moisture profile of Figure 6, irrigation is performed during (or shortly before) the period when the soil moisture content curve rises, and irrigation is stopped during (or shortly before) the period when the soil moisture content curve falls.

[0083] FIG. 7 is a diagram showing a second example of a target soil moisture profile.

[0084] In the target soil moisture profile of FIG. 7, roughly speaking, a curve of soil moisture amount having a substantially triangular wave shape is defined, similarly to the case of FIG.

[0085] However, the soil moisture curve in Fig. 7 is a gentle curve during a predetermined period D1 when the soil moisture rises from the lower reference value RL. Furthermore, the soil moisture curve in Fig. 7 is a gentle curve during a predetermined period D2 when the soil moisture reaches its peak. Furthermore, the soil moisture curve in Fig. 7 is a curve during the nighttime D3 when the soil moisture falls below the lower reference value RL and the soil becomes dry.

[0086] According to the control signal generated based on the target soil moisture profile in Fig. 7, the amount of irrigation performed just before night falls is reduced compared to the amount of other irrigation performed during the day so that the soil moisture content is equal to or less than the lower reference value RL during the night D3. As a result, the peak of the soil moisture content just before night falls is lower than the other peaks of the daytime soil moisture content.

[0087] FIG. 8 is a diagram showing a third example of a target soil moisture profile.

[0088] The target soil moisture profile can define a curve of the soil moisture amount that is targeted in a given situation depending on the conditions of the target field, such as the growth condition and growth stage of the crops, and the condition of the soil.

[0089] Fig. 8A shows a target soil moisture profile that defines a target soil moisture curve in a certain situation s1. Fig. 8B shows a target soil moisture profile that defines a target soil moisture curve in a situation s2 that is different from situation s1. Fig. 8C shows a target soil moisture profile that defines a target soil moisture curve in a situation s3 that is different from situations s1 and s2.

[0090] For example, the target soil moisture profile of Figure 8A is similar to the target soil moisture profile of Figure 7. In the target soil moisture profile of Figure 8B, the soil moisture content is slightly higher overall compared to the target soil moisture profile of Figure 8A. In the target soil moisture profile of Figure 8C, the soil moisture content is slightly lower overall compared to the target soil moisture profiles of Figures 8A and 8B, and further, the change in soil moisture content is much more gradual.

[0091] By specifying an appropriate soil moisture curve for the target soil moisture profile according to the conditions of the target field, it is expected that quality and yield can be controlled, such as to improve quality and yield.

[0092] FIG. 9 is a diagram showing an example of a target soil moisture profile that defines a soil moisture curve according to the condition of a target field.

[0093] FIG. 9 shows an example of a target soil moisture profile that defines a soil moisture curve according to the growth stage of the crop as the condition of the target field.

[0094] In the target soil moisture profile of Figure 9, for example, for grapes, soil moisture curves are defined for each of the growth stages from budding to flowering and fruit set, the growth stage from flowering and fruit set to veraison, the growth stage from veraison to harvest, and the growth stage after harvest.

[0095] FIG. 10 is a diagram showing a fourth example of a target soil moisture profile.

[0096] The target soil moisture profiles of Figures 6 to 9 specify the curve of the target soil moisture content, but the target soil moisture profile can also specify an upper limit value TH and / or a lower limit value TL of the target soil moisture content.

[0097] 10A shows a target soil moisture profile in which both an upper limit value TH and a lower limit value TL are specified. FIG. 10B shows a target soil moisture profile in which only an upper limit value TH is specified. FIG. 10C shows a target soil moisture profile in which only a lower limit value TL is specified. In FIG. 10, the upper limit value TH and the lower limit value TL are constant, but the upper limit value TH and the lower limit value TL can be set according to the conditions of the target field. For example, the upper limit value TH and the lower limit value TL can be set to different values ​​for each growth stage, such as the upper reference value RH and the lower reference value RL in FIG. 9, depending on the crop growth stage described in FIG. 9.

[0098] It should be noted that a target soil moisture profile that specifies an upper limit TH and a lower limit TL can be considered to specify a time series of soil moisture content that is greater than or equal to the lower limit TL and less than or equal to TH. When a target soil moisture profile that specifies an upper limit TH and a lower limit TL of soil moisture content is used, generating a control signal so that the soil moisture content obtained from the sensor data of the moisture sensor (observed soil moisture content) matches the target soil moisture profile means generating a control signal so that the soil moisture content obtained from the sensor data of the moisture sensor is greater than or equal to the lower limit TL and less than or equal to TH. The same applies to a target soil moisture profile that specifies only the upper limit TH or the lower limit TL.

[0099] The target soil moisture profile can specify a target soil moisture content for one location in the soil, or can specify a target soil moisture content for each of multiple locations in the soil.

[0100] FIG. 11 is a diagram showing a schematic example of a target soil moisture profile for one location in the soil.

[0101] The target soil moisture profile for a soil location defines a target soil moisture content v for a soil location.

[0102] In Figure 11, the soil moisture content (observed soil moisture content) obtained from the sensor data of a specific moisture sensor installed in the soil and the target soil moisture content (target soil moisture content value obtained from the sensor data of a specific moisture sensor) v are arranged in chronological order horizontally in the figure.

[0103] In the target soil moisture profile shown in Fig. 11, the time series of the target soil moisture content v obtained from the sensor data of a specific moisture sensor is arranged one-dimensionally (in a straight line). Therefore, the target soil moisture profile shown in Fig. 11 can be said to be a one-dimensional profile.

[0104] When the target soil moisture profile is a one-dimensional profile, the control device 12 generates a control signal based on the one-dimensional target soil moisture profile so that the soil moisture amount obtained from the sensor data of a specific moisture sensor matches the target soil moisture profile.

[0105] That is, the control device 12 generates a control signal so that the soil moisture content obtained from the sensor data of a specific moisture sensor matches the time series of the target soil moisture content v specified in the target soil moisture profile, which is a one-dimensional profile.

[0106] FIG. 12 is a diagram schematically illustrating an example of a target soil moisture profile for each of a plurality of locations in the soil.

[0107] In the target soil moisture profile for each of the multiple soil locations, the target soil moisture content v n is stipulated.

[0108] 12 is based on the premise that multiple N moisture sensors are installed in a specific (linear) direction in the soil, for example, in the depth direction. In FIG. 12, the N soil moisture amounts obtained from the sensor data of each of the N moisture sensors are expressed as target soil moisture amounts (target values ​​for each of the N soil moisture amounts obtained from the sensor data of each of the N moisture sensors) v n The time series are arranged in a specific direction vertically and time horizontally.

[0109] The nth soil moisture content from the top in the vertical direction is v n The time series (arranged horizontally) is a time series of soil moisture content that is the target soil moisture content obtained from the sensor data of the nth moisture sensor among N moisture sensors arranged in a specific direction.

[0110] In the target soil moisture profile shown in Figure 12, the soil moisture amount obtained from the sensor data of N moisture sensors arranged in a specific direction is the target soil moisture amount v nThe time series of the above is arranged two-dimensionally (on a plane). Therefore, the target soil moisture profile in Fig. 12 can be said to be a two-dimensional profile.

[0111] When the target soil moisture profile is a two-dimensional profile, the control device 12 generates a control signal based on the two-dimensional target soil moisture profile so that each of the N soil moisture amounts obtained from the sensor data of each of the N moisture sensors lined up in a specific direction matches the target soil moisture profile.

[0112] That is, in the control device 12, for each of the N moisture sensors arranged in a specific direction, the soil moisture content obtained from the sensor data of the n-th moisture sensor is calculated based on the n-th target soil moisture content v from the top defined in the target soil moisture profile, which is a two-dimensional profile. n The control signal is generated to match the time series of

[0113] FIG. 13 is a diagram schematically showing another example of a target soil moisture profile for each of a plurality of locations in the soil.

[0114] 13 is based on the premise that a plurality of Nx*Ny moisture sensors, for example, Nx sensors in the x direction and Ny sensors in the y direction, are installed on a specific xy plane of the soil, for example, an xy plane in which the depth direction is the x axis and a specific direction parallel to the earth's surface is the y direction. In FIG. 13, the Nx*Ny soil moisture amounts obtained from the sensor data of each of the Nx*Ny moisture sensors are used as target soil moisture amounts (target values ​​for each of the Nx*Ny soil moisture amounts obtained from the sensor data of each of the Nx*Ny moisture sensors) v nx,ny The time series of the above images are arranged in a row with the vertical and depth directions being the x and y directions, respectively, and the horizontal direction being time.

[0115] The nxth vertical axis from the top and the nyth vertical axis from the front are the soil moisture content v nx,nyThe time series (horizontal arrangement) of is the time series of the target soil moisture content obtained from the sensor data of the nxth moisture sensor in the x direction and the nyth moisture sensor in the y direction out of the Nx*Ny moisture sensors arranged on a specific xy plane.

[0116] In the target soil moisture profile shown in Figure 13, the soil moisture amount obtained from the sensor data of Nx*Ny moisture sensors arranged on a specific xy plane is the target soil moisture amount v nx,ny The time series of the above are arranged three-dimensionally (stereoscopically). Therefore, the target soil moisture profile in Fig. 13 can be said to be a three-dimensional profile.

[0117] If the target soil moisture profile is a three-dimensional profile, the control device 12 generates a control signal based on the three-dimensional target soil moisture profile so that each of the Nx*Ny soil moisture amounts obtained from the sensor data of each of the Nx*Ny moisture sensors arranged on a specific xy plane matches the target soil moisture profile.

[0118] That is, in the control device 12, for each of the Nx*Ny moisture sensors arranged on a specific xy plane, the soil moisture content obtained from the sensor data of the nx-th moisture sensor in the x direction and the ny-th moisture sensor in the y direction is calculated as the target soil moisture content v nx,ny The control signal is generated to match the time series of

[0119] Alternatively, the target soil moisture profile for each of multiple locations in the soil may be a four-dimensional profile in which time series of target soil moisture content v for moisture sensors installed at any three-dimensional position (x, y, z) in the soil are arranged.Furthermore, the target soil moisture profile for each of multiple locations in the soil may be a profile in which identification information for identifying each moisture sensor is assigned to each of multiple moisture sensors installed in the soil, and a time series of target soil moisture content v for each moisture sensor identified by the identification information is arranged.

[0120] FIG. 14 is a diagram illustrating an example of generating a target soil moisture profile using the input device 11.

[0121] The input device 11 can display, for example, a curve of the soil moisture amount defined in the default target soil moisture profile.

[0122] The user can modify the soil moisture curve displayed on the input device 11 to a desired soil moisture curve by performing an operation such as dragging on the soil moisture curve displayed on the input device 11. The input device 11 generates a target soil moisture profile that defines the modified soil moisture curve.

[0123] <Configuration example of control device 12>

[0124] FIG. 15 is a block diagram showing an example of the configuration of the control device 12.

[0125] In FIG. 15 , the control device 12 includes a storage unit 91 and a generation unit 92 .

[0126] The storage unit 91 receives (acquires) and stores a target profile, for example, a target soil moisture profile, supplied from the input device 11 .

[0127] The generating unit 92 generates a control signal with a variable pulse width and / or pulse interval as a control signal for controlling irrigation, and supplies the control signal to the irrigation device 41 .

[0128] The generation unit 92 acquires sensor data from the sensor group 13 and also acquires a target profile, for example, a target soil moisture profile, stored in the memory unit 91. Based on the target soil moisture profile, the generation unit 92 generates a control signal whose pulse width and / or pulse interval are adjusted so that the observed soil moisture amount acquired from the sensor data of the moisture sensor among the sensor data of the sensor group 13 matches the target soil moisture profile, and supplies the control signal to the irrigation device 41.

[0129] The generation unit 92 includes a parameter setting unit 111 and a simulator 112 .

[0130] The parameter setting unit 111 calculates the error of the observed soil moisture content, which is acquired from the sensor data of the moisture sensor among the sensor data acquired by the generation unit 92, relative to (the soil moisture content defined in) the target soil moisture profile acquired by the generation unit 92. Based on the error of the observed soil moisture content, the parameter setting unit 111 calculates physical parameters related to soil, plants, weather, etc. of the mathematical model (physical model) used by the simulator 112, and sets them in (the mathematical model used by) the simulator 112. In other words, the parameter setting unit 111 updates the physical parameters of the simulator 112 so as to reduce the error of the observed soil moisture content.

[0131] The simulator 112 simulates the soil moisture content, i.e., calculates the time evolution of the soil moisture content, in accordance with a predetermined mathematical model (physical model) that represents the soil moisture content, thereby predicting the soil moisture content at one or more locations in the soil where the moisture sensors are installed when irrigation is performed. The soil moisture content predicted by the simulator 112 is also referred to as the predicted moisture content.

[0132] The generation unit 92 generates a control signal to control irrigation so as to obtain a predicted moisture amount that matches the target soil moisture profile for each of one or more locations in the soil where the moisture sensor is installed, and supplies the control signal to the irrigation device 41.

[0133] The simulator 112 can supply a prediction profile that defines a time series of predicted moisture content to the parameter setting unit 111. The parameter setting unit 111 can perform initial setting of physical parameters of a mathematical model used by the simulator 112 based on the prediction profile from the simulator 112.

[0134] The generating unit 92 can also obtain a weather forecast for the target field from the weather database 22 via the network 21 and generate a control signal based on the weather forecast.

[0135] <Simulation of soil moisture content by simulator 112>

[0136] FIG. 16 is a diagram illustrating an example of a mathematical model used in the simulation of soil moisture content by the simulator 112.

[0137] In FIG. 16, the three-dimensional unsteady Richards equation is adopted as the mathematical model used for simulating soil moisture content (calculating predicted moisture content).

[0138] For example, if the van Genuchten model is used as a mathematical model to represent soil properties, the simulation uses the soil water pressure h calculated according to the three-dimensional unsteady Richards equation, and calculates the volumetric water content θ as the soil moisture content according to the equation Se = (θ - θr) / (θs - θr) = (1 + |αh|^n)^(-m).

[0139] The parameter setting unit 111 sets the variables that define the specific water capacity Cw(h) of the three-dimensional unsteady Richards equation, the variables that define the unsaturated hydraulic conductivity K(h), and the variables that define the absorption term S(h) (excluding the soil water pressure h) as physical parameters.

[0140] When the van Genuchten model is used, the variables that determine the specific water capacity Cw(h) are α, n, θs, and θr of the van Genuchten model, and the variables that determine the unsaturated hydraulic conductivity K(h) are k, Se, m, and l of the van Genuchten model. The variable θs represents the saturated volumetric water content, and the variable θr represents the residual volumetric water content. The variable k represents the saturated hydraulic conductivity, and the variable Se represents the effective degree of saturation. The variables α, n, m, and l are predetermined coefficients.

[0141] When using the Feddes equation to predict plant root absorption, the variables that determine the absorption term S(h) are the variable that determines the water absorption function a(h) of the Feddes equation, the variable B which is a predetermined coefficient, and the transpiration rate Tp.

[0142] When Campbell's formula is used to express transpiration, the transpiration rate Tp is determined by the evapotranspiration rate ET and leaf area index LAI of Campbell's formula.

[0143] When the Blaney Criddle equation is used to express evapotranspiration, the amount of evapotranspiration ET is determined by the crop coefficient Kc of the Blaney Criddle equation, information dl about the number of hours of sunlight, and information T about the air temperature.

[0144] In addition, in the simulation of soil moisture content, variables other than those mentioned above can be introduced as physical parameters.

[0145] Furthermore, the mathematical model used for simulating soil moisture content is not limited to the three-dimensional unsteady Richards equation, and any mathematical model that can predict soil moisture content can be used.

[0146] Furthermore, a machine learning model using a neural network or the like can be used to simulate soil moisture content, i.e., predict soil moisture content.

[0147] <Example of irrigation control by the control device 12>

[0148] FIG. 17 is a diagram illustrating an example of irrigation control by the control device 12.

[0149] The generating unit 92 generates a pulse signal as a control signal for irrigating so that the soil moisture amount predicted by the simulation of the simulator 112 (predicted moisture amount) coincides with the target soil moisture profile.

[0150] The generating unit 92 supplies the control signal to the irrigation device 41. The irrigation device 41 performs irrigation in accordance with the control signal from the generating unit 92.

[0151] Thereafter, the generating unit 92 generates the next control signal based on the error between the observed soil moisture amount after irrigation performed in accordance with the control signal and the target soil moisture profile.

[0152] That is, the generator 92 compares the observed soil moisture obtained from the sensor data after irrigation in accordance with the control signal with the target soil moisture profile, calculates the error of the observed soil moisture from the target soil moisture profile, and updates the physical parameters of the simulator 112 so as to reduce the error of the observed soil moisture.

[0153] The generating unit 92 generates a pulse signal as a next control signal for irrigating so that the amount of soil moisture predicted by the simulation after updating the physical parameters matches the target soil moisture profile.

[0154] Similar processing is repeated to identify the physical parameters of the simulator 112 that will cause the soil moisture amount predicted by the simulation to match the target soil moisture profile. As the physical parameters are identified, a control signal for irrigating the soil so that the soil moisture amount predicted by the simulation matches the target soil moisture profile is also identified.

[0155] When target soil moisture profiles are used for multiple soil locations, the error of the observed soil moisture at each of the multiple locations from the target soil moisture profile is calculated. In this case, the physical parameters of the simulator 112 are updated so as to reduce the combined value of the errors of the observed soil moisture at each of the multiple locations from the target soil moisture profile, such as the sum or product of the errors.

[0156] The physical parameters of the simulator 112 can be updated after irrigation is performed in accordance with a plurality of pulses (H-level portions of the pulse signal) as a control signal, for example, a plurality of pulses corresponding to a period during which the soil moisture curve defined in the target soil moisture profile increases. Furthermore, the physical parameters can be updated after irrigation is performed in accordance with a single pulse as a control signal.

[0157] FIG. 18 is a diagram illustrating updating of the physical parameters of the simulator 112 after irrigation is performed in accordance with one pulse as a control signal.

[0158] 18 , one pulse is generated as a control signal for irrigating so that the soil moisture amount predicted by the simulation of the simulator 112 coincides with the target soil moisture profile. Then, after irrigation is performed in accordance with this one pulse as a control signal, the physical parameters of the simulator 112 are updated so as to reduce the error between the observed soil moisture amount obtained from the sensor data after irrigation and the target soil moisture profile. Furthermore, one pulse is generated as a next control signal for irrigating so that the soil moisture amount predicted by the simulation of the simulator 112 after the physical parameters have been updated coincides with the target soil moisture profile, and similar processing is repeated thereafter.

[0159] FIG. 19 is a flowchart illustrating an example of the process of controlling irrigation by the control device 12.

[0160] In step S21, the generation unit 92 acquires (reads) a target profile stored in the storage unit 91, for example, a target soil moisture profile, and supplies it to the parameter setting unit 111 and the simulator 112, and the process proceeds to step S22.

[0161] In step S22, the parameter setting unit 111 performs initial setting of the physical parameters of the simulator 112, and the process proceeds to step S23.

[0162] In step S23, the simulator 112 generates a pulse signal as a control signal for irrigating so that the soil moisture amount predicted by the simulation (predicted moisture amount) matches the target soil moisture profile, and the process proceeds to step S24.

[0163] In step S24, the generation unit 92 outputs a control signal, and the process proceeds to step S25. The control signal output by the generation unit 92 is supplied to the irrigation device 41, and as a result, the irrigation device 41 performs irrigation in accordance with the control signal.

[0164] In step S25, the parameter setting unit 111 acquires sensor data from the sensor group 13, for example, sensor data from a moisture sensor, and acquires the observed soil moisture content from the sensor data, after which the process proceeds to step S26. For example, the sensor data from the moisture sensor can be used as the observed soil moisture content as is.

[0165] In step S26, the parameter setting unit 111 generates an error of the observed soil moisture amount relative to the target soil moisture profile, and the process proceeds to step S27.

[0166] In step S27, the parameter setting unit 111 updates the physical parameters of the simulator 112 so as to reduce the error in the observed soil moisture content. Then, the process returns from step S27 to step S23, and the processes of steps S23 to S27 are repeated.

[0167] By repeating the processes of steps S23 to S27, the physical parameters of the simulator 112 become values ​​that match the conditions of the target field, and the error between the observed soil moisture content and the target soil moisture profile becomes small. As a result, the physical parameters are hardly updated (converged), and a highly accurate control signal, i.e., a control signal for irrigation that observes soil moisture content that (almost) matches the target soil moisture profile, is generated.

[0168] In the initial setting of the physical parameters in step S22, for example, typical values ​​of the physical parameters can be prepared as default values ​​and set as the initial values ​​of the physical parameters. Alternatively, for example, in the initial setting of the physical parameters, values ​​that match the conditions of the target field can be set as the initial values ​​of the physical parameters.

[0169] FIG. 20 is a flowchart illustrating an example of processing for initial setting of physical parameters, in which values ​​that match the conditions of the target field are set as the initial values ​​of the physical parameters.

[0170] In step S31, the parameter setting unit 111 sets the default values ​​of the physical parameters prepared in advance as the initial values ​​of the physical parameters, and the process proceeds to step S32.

[0171] In step S32, the simulator 112 simulates the soil moisture content (predicted moisture content) when irrigation is performed in accordance with a predetermined control signal. The simulator 112 supplies the predicted moisture content (predicted profile) to the parameter setting unit 111, and the process proceeds from step S32 to step S33. Any pulse signal can be used as the predetermined control signal. For example, a single pulse or multiple pulses can be used as the predetermined control signal. Furthermore, for example, a pulse signal with a variable pulse width and / or pulse interval that irrigates the soil so that the soil moisture content predicted by the simulation matches the target soil moisture profile, i.e., a pulse signal as the control signal generated in step S23 of FIG. 19, can be used as the predetermined control signal.

[0172] In step S33, the generation unit 92 outputs a predetermined control signal, and the process proceeds to step S34. The control signal output by the generation unit 92 is supplied to the irrigation device 41, which then performs irrigation in accordance with the control signal.

[0173] In step S34, the parameter setting unit 111 acquires sensor data from the moisture sensor, and acquires the observed soil moisture content from the sensor data, and the process proceeds to step S35.

[0174] In step S35, an error between the predicted moisture content and the observed soil moisture content is generated, and the process proceeds to step S36.

[0175] In step S36, the parameter setting unit 111 updates the physical parameters of the simulator 112 so as to reduce the error in the predicted moisture content. Note that if the error in the predicted moisture content is small, the updating of the physical parameters in step S36 can be skipped.

[0176] Thereafter, the process returns from step S36 to step S32, and the processes of steps S32 to S36 are repeated.

[0177] By repeating the processes of steps S32 to S36, the physical parameters of the simulator 112 become values ​​that match the conditions of the target field, and the error between the predicted moisture content and the observed soil moisture content becomes smaller.

[0178] When the error in the predicted moisture content becomes small, for example, when the magnitude of the error in the predicted moisture content becomes less than a threshold value, the processing from step S23 onward in FIG. 19 can be started.

[0179] As described above, by setting the initial values ​​of the physical parameters to values ​​that match the conditions of the target field in the initial setting of the physical parameters, the accuracy of the simulation by the simulator 112, i.e., the accuracy of the prediction of the predicted water content, can be improved. As a result, the identification of the physical parameters, which is performed by the repeated processing of steps S23 to S27 in FIG. 19 , can be completed in a short period of time. Furthermore, by continuously repeating the processing of steps S32 to S36, if the error in the predicted water content becomes small after time has passed and the error in the predicted water content increases due to changes in the conditions of the target field, such as weather changes due to the change of seasons or plant growth, the physical parameters are updated to reduce the error in the predicted water content.

[0180] <Generating control signals based on weather forecasts>

[0181] FIG. 21 is a diagram illustrating an example of generation of a control signal based on a weather forecast.

[0182] As described with reference to FIG. 15 and other figures, the generation unit 92 can generate a control signal based on a weather forecast as well.

[0183] For example, the target soil moisture profile specifies that the soil moisture content fluctuates between a lower reference value RL and an upper reference value RH during the day, and falls below the lower reference value RL at night.

[0184] FIG. 21A shows an example of a time series of observed soil moisture content when irrigation is performed in accordance with a control signal generated without taking into account the weather forecast.

[0185] In Figure 21A, irrigation is performed at time t1 during the day until the soil moisture content increases from the lower reference value RL to the upper reference value RH, and then, at time t3 just before night, irrigation is performed until the soil moisture content increases from the lower reference value RL to a value that does not reach the upper reference value RH, i.e., irrigation with a smaller amount of water than the irrigation at time t1 during the day.

[0186] The amount of irrigation water at time t3, just before night, is less than the amount of irrigation water at time t1 during the day, so that the soil moisture content at night falls below the lower reference value RL, as specified in the target soil moisture profile.

[0187] In Fig. 21A, the control signal is generated without considering the weather forecast, for example, assuming only sunny weather. Therefore, when the weather is not sunny and irrigation is performed according to the control signal generated assuming sunny weather, the soil moisture content may deviate significantly from the target soil moisture profile.

[0188] For example, in Figure 21A, after daytime t1, the weather changes from sunny to cloudy at time t2, just before nighttime t3. Therefore, the amount of evaporation from the soil decreases from time t2 onwards compared to before. Because the amount of evaporation from the soil decreases from time t2 onwards, if irrigation is performed at time t3 just before nightfall, the soil moisture content will not fall below the lower reference value RL even at nightfall, and will deviate significantly from the target soil moisture profile.

[0189] FIG. 21B shows an example of a time series of observed soil moisture content when irrigation is performed in accordance with a control signal generated based on a weather forecast.

[0190] If the weather forecast predicts that the weather will change from sunny to cloudy midday, the generation unit 92 generates a control signal based on the weather forecast that irrigates less water than a control signal generated by a simulation performed without considering the weather forecast (e.g., assuming sunny skies). For example, as shown in B of FIG. 21 , the generation unit 92 generates a control signal that irrigates less water at time t1 in the daytime than in A of FIG. 21 , and does not irrigate at time t3 just before nightfall. By irrigating in accordance with this control signal, the soil moisture content at night falls below the lower reference value RL, allowing the soil moisture content to match the target soil moisture profile.

[0191] In generating a control signal based on a weather forecast, for example, if the weather forecast predicts rain or the probability of precipitation is equal to or greater than a threshold, a control signal can be generated that irrigates less water than a control signal generated by a simulation performed without considering the weather forecast, depending on the duration of the rain and the probability of precipitation. Also, if the weather forecast predicts a temperature that is higher than the average temperature by more than a threshold, a control signal can be generated that irrigates more water than a control signal generated by a simulation performed without considering the weather forecast, depending on the difference from the average temperature.

[0192] <Another example of irrigation control by the control device 12>

[0193] FIG. 22 is a flowchart illustrating another example of the process of controlling irrigation by the control device 12.

[0194] In Figure 19, a target soil moisture profile that specifies the target soil moisture content is adopted as the target profile, but in Figure 22, a target water stress profile that specifies the target water stress value is adopted as the target profile.

[0195] For plants, environmental stresses such as water stress that plants experience affect their yield and quality. Therefore, for example, by applying appropriate water stress to plants, yield and quality can be controlled.

[0196] When a target water stress profile is adopted as the target profile, the input device 11 acquires the target water stress profile in response to a user operation and supplies (transmits) it to the control device 12. In the control device 12 (FIG. 15), the target water stress profile from the input device 11 is supplied to and stored in the memory unit 91.

[0197] In step S51, the generation unit 92 acquires (reads) the target water stress profile stored in the storage unit 91, supplies it to the parameter setting unit 111 and the simulator 112, and the processing proceeds to step S52.

[0198] In step S52, the parameter setting unit 111 performs initial setting of the physical parameters of the simulator 112, similar to step S22 in FIG. 19, and the process proceeds to step S53.

[0199] In step S53, the simulator 112 generates a pulse signal as a control signal for irrigating so that the water stress value estimated using the soil moisture content predicted by the simulation (predicted moisture content) coincides with the target water stress profile, and the process proceeds to step S54. The water stress value estimated using the soil moisture content can be, for example, a value that serves as an indicator of water stress, such as tree water tension. Estimation of the water stress value using the soil moisture content can be performed using, for example, a regression model or a machine learning model. The water stress value can be estimated using not only the soil moisture content (predicted moisture content) but also meteorological information such as temperature, humidity, solar radiation, and wind speed. Using meteorological information together with the soil moisture content to estimate the water stress value can improve the accuracy of the water stress value estimation.

[0200] In step S54, the generation unit 92 outputs a control signal, and the process proceeds to step S55. The control signal output by the generation unit 92 is supplied to the irrigation device 41, and as a result, the irrigation device 41 performs irrigation in accordance with the control signal.

[0201] In step S55, the parameter setting unit 111 acquires sensor data from the sensor group 13 and acquires an observed value of water stress (also referred to as an observed water stress value) from the sensor data, and the process proceeds to step S56. For example, the observed water stress value can be acquired from sensor data from the stress sensor 31. Also, for example, the observed water stress value can be estimated in the same manner as in step S53, using the observed soil moisture content acquired from sensor data from the moisture sensor.

[0202] In step S56, the parameter setting unit 111 generates an error of the observed water stress value with respect to the target water stress profile, and the process proceeds to step S57.

[0203] In step S57, the parameter setting unit 111 updates the physical parameters of the simulator 112 so as to reduce the error in the observed water stress value. Then, the process returns from step S57 to step S53, and the processes of steps S53 to S57 are repeated.

[0204] By repeating the processes of steps S53 to S57, the physical parameters of the simulator 112 become values ​​that match the conditions of the target field, and the error between the observed water stress value and the target water stress profile becomes small. As a result, the physical parameters are hardly updated, and a highly accurate control signal is generated, i.e., a control signal for irrigating to provide a soil moisture content that will result in an observed water stress value that matches the target water stress profile.

[0205] As described above, the generator 92 generates a pulse signal as a control signal for irrigating soil so that the water stress value estimated from the soil moisture content (predicted moisture content) predicted by the simulation of the simulator 112 coincides with the target water stress profile. The irrigation device 41 then irrigates soil in accordance with the control signal. The generator 92 then generates a next control signal based on the error between the observed water stress value after irrigation in accordance with the control signal and the target water stress profile. That is, the generator 92 compares the observed water stress value after irrigation in accordance with the control signal with the target water stress profile and calculates the error between the observed water stress value and the target water stress profile. The generator 92 updates the physical parameters of the simulator 112 to reduce the error between the observed water stress value and the target water stress profile. The generator 92 generates a pulse signal as a next control signal for irrigating soil so that the water stress value estimated from the soil moisture content predicted by the simulation after the physical parameters are updated coincides with the target water stress profile. The same process is repeated. This identifies the physical parameters of the simulator 112 that allow the water stress value estimated from the soil moisture content predicted by the simulation to coincide with the target soil moisture profile. As these physical parameters are identified, control signals for irrigation are also identified so that the water stress value estimated from the soil moisture content predicted by the simulation matches the target water stress profile.

[0206] FIG. 23 is a diagram showing an example of a time series of observed soil moisture content when a target soil moisture profile is adopted as the target profile and when a target water stress profile is adopted.

[0207] 23, the upper reference value RH and the lower reference value RL represent the upper and lower limits, respectively, of a range of values, for example, as daytime soil moisture, that are appropriate for the growth of the plant to be irrigated. The upper reference value rH and the lower reference value rL represent the upper and lower limits, respectively, of a range of values, for example, as daytime soil moisture, that are appropriate for providing the plant with appropriate water stress for controlling the quality and yield of the plant to be irrigated.

[0208] Fig. 23A shows an example of a time series of observed soil moisture content when a target soil moisture profile is adopted as the target profile, and Fig. 23B shows an example of a time series of observed soil moisture content when a target water stress profile is adopted as the target profile.

[0209] When the target soil moisture profile is adopted, the observed daytime soil moisture (A in FIG. 23) fluctuates between the upper reference value RH and the lower reference value RL. When the target water stress profile is adopted, the observed daytime soil moisture (B in FIG. 23) fluctuates between the upper reference value rH and the lower reference value rL.

[0210] Managing plant water stress improves control over plant quality and yield.

[0211] The upper reference value rH and the lower reference value rL when the target water stress profile is adopted are smaller than the upper reference value RH and the lower reference value RL when the target soil moisture profile is adopted. That is, in the example of Figure 23, in order to apply an appropriate amount of water stress to the plant, the observed soil moisture content when the target water stress profile is adopted is, overall, smaller than the observed soil moisture content when the target soil moisture profile is adopted.

[0212] The above describes the application of this technology to a farm field as the location for irrigation, but this technology can also be applied to irrigating any other soil, such as the soil where grass grows in sports stadiums, racetracks, parks, etc.

[0213] <Description of a computer to which this technology is applied>

[0214] Next, the above-described series of processes can be performed by hardware or software. When the series of processes is performed by software, the programs that make up the software are installed on a general-purpose computer or the like.

[0215] FIG. 24 is a block diagram showing an example of the configuration of an embodiment of a computer in which a program for executing the above-described series of processes is installed.

[0216] The program can be recorded in advance on the hard disk 905 or ROM 903 as a recording medium built into the computer.

[0217] Alternatively, the program can be stored (recorded) on a removable recording medium 911 driven by the drive 909. Such a removable recording medium 911 can be provided as a so-called package software. Here, examples of the removable recording medium 911 include a flexible disk, a CD-ROM (Compact Disc Read Only Memory), an MO (Magneto Optical) disk, a DVD (Digital Versatile Disc), a magnetic disk, and a semiconductor memory.

[0218] The program can be installed into the computer from the removable recording medium 911 as described above, or can be downloaded to the computer via a communication network or a broadcasting network and installed on the built-in hard disk 905. That is, the program can be transferred to the computer wirelessly from a download site via an artificial satellite for digital satellite broadcasting, or transferred to the computer via a wired network such as a LAN (Local Area Network) or the Internet.

[0219] The computer includes a CPU (Central Processing Unit) 902 , to which an input / output interface 910 is connected via a bus 901 .

[0220] When a user inputs a command via an input / output interface 910 by operating an input unit 907, the CPU 902 executes a program stored in a read-only memory (ROM) 903 in accordance with the command. Alternatively, the CPU 902 loads a program stored on a hard disk 905 into a random access memory (RAM) 904 and executes the program.

[0221] As a result, the CPU 902 performs processing according to the flowchart described above or processing performed by the configuration of the block diagram described above. Then, the CPU 902 outputs the processing results from the output unit 906 via the input / output interface 910, or transmits them from the communication unit 908, or further records them on the hard disk 905, as necessary.

[0222] The input unit 907 is made up of a keyboard, a mouse, a microphone, etc. The output unit 906 is made up of an LCD (Liquid Crystal Display), a speaker, etc.

[0223] In this specification, the processing performed by a computer according to a program does not necessarily have to be performed in chronological order according to the order described in the flowchart. In other words, the processing performed by a computer according to a program also includes processing that is executed in parallel or individually (for example, parallel processing or object-based processing).

[0224] The program may be processed by a single computer (processor), or may be distributed among multiple computers. Furthermore, the program may be transferred to and executed on a remote computer.

[0225] Furthermore, in this specification, a system refers to a collection of multiple components (devices, modules (components), etc.), regardless of whether all of the components are contained in the same housing. Therefore, multiple devices housed in separate housings and connected via a network, and a single device housed in a single housing with multiple modules, are both systems.

[0226] It should be noted that the embodiments of the present technology are not limited to the above-described embodiments, and various modifications are possible within the scope of the present technology.

[0227] For example, the present technology can be configured as a cloud computing system in which a single function is shared and processed collaboratively by a plurality of devices via a network.

[0228] Furthermore, each step described in the above flowchart can be executed by one device, or can be shared and executed by a plurality of devices.

[0229] Furthermore, when one step includes multiple processes, the multiple processes included in that one step can be executed by one device or can be shared and executed by multiple devices.

[0230] Furthermore, the effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0231] The present technology can have the following configurations.

[0232] <1> A control device including a generation unit that generates a control signal having a variable pulse width and / or pulse interval as a control signal for controlling irrigation. <2> The control device described in <1>, in which the generation unit generates the control signal with the pulse width and / or pulse interval adjusted based on target environment information related to a target environment. <3> The control device described in <2>, in which the generation unit generates the control signal with the pulse width and / or pulse interval adjusted based on a target soil moisture profile of a target soil moisture content. <4> The control device described in <3>, in which the generation unit generates the control signal based on the target soil moisture profile for one location or for each of multiple locations in the soil. <5> The control device described in <3> or <4>, in which the target soil moisture profile is acquired in response to a user operation. <6> The control device described in any of <3> to <5>, in which the generation unit generates the control signal for irrigating so that a soil moisture amount predicted by a simulator that predicts soil moisture content matches the target soil moisture profile. <7> The control device according to <6>, wherein the generation unit generates the next control signal based on an error between an observed soil moisture content, which is an observed value of soil moisture content after irrigation performed in accordance with the control signal, and the target soil moisture profile. <8> The control device according to <7>, wherein the generation unit updates physical parameters of the simulator so as to reduce the error between the observed soil moisture content. <9> The control device according to <8>, wherein the generation unit sets the physical parameters in an initial setting of the physical parameters so as to reduce an error between the soil moisture content predicted by the simulator and the observed soil moisture content. <10> The control device according to any of <3> to <9>, wherein the target soil moisture profile specifies an upper limit and / or a lower limit of a target soil moisture content range. <11> The control device according to <2>, wherein the generation unit generates the control signal in which a pulse width and / or a pulse interval is adjusted based on a target water stress profile of a target water stress value for a plant. <12> The control device according to <11>, wherein the target water stress profile is acquired in response to a user operation.<13> The control device according to <11> or <12>, wherein the generation unit generates the control signal for irrigating so that a water stress value estimated using soil moisture content predicted by a simulator that predicts soil moisture content matches the target water stress profile. <14> The control device according to <13>, wherein the generation unit generates the next control signal based on an error, from the target water stress profile, of an observed water stress value, which is an observation value of water stress after irrigation performed in accordance with the control signal. <15> The control device according to <14>, wherein the generation unit updates physical parameters of the simulator so as to reduce the error in the observed water stress value. <16> The control device according to any of <1> to <15>, wherein the generation unit generates the control signal based on a weather forecast. <17> The control device according to any of <1> to <16>, wherein the generation unit generates a plurality of the control signals for controlling a plurality of irrigation systems. <18> The control device according to any of <1> to <16>, wherein the generation unit generates another control signal for controlling the environment. <19> A control method including generating a control signal having a variable pulse width and / or a variable pulse interval as a control signal for controlling irrigation. <20> A program causing a computer to function as a generating unit that generates a control signal having a variable pulse width and / or a variable pulse interval as a control signal for controlling irrigation.

[0233] 10 Environmental control system, 11 Input device, 12 Control device, 13 Sensor group, 14 Environmental control equipment group, 21 Network, 22 Weather database, 31 Stress sensor, 32 Weather sensor, 33 Soil sensor, 41 Irrigation device, 42 Electric curtain, 43 Heater, 44 Humidifier, 45 Fan, 60 Irrigation control system, 71 Support, 72 Pipe, 73 Communication cable, 74 Water pipe, 75 Emitter unit, 76 Electric valve, 77 Irrigation emitter, 78 Water pump, 79 Water tank, 91 Memory unit, 92 Generation unit, 111 Parameter setting unit, 112 Simulator, 901 Bus, 902 CPU, 903 ROM, 904 RAM, 905 Hard disk, 906 Output unit, 907 Input unit, 908 Communication unit, 909 Drive, 910 Input / output interface, 911 Removable recording medium

Claims

1. A control device having a generating unit that generates a control signal with a variable pulse width and / or pulse interval as a control signal for controlling irrigation.

2. The control device according to claim 1, wherein the generation unit generates the control signal in which the pulse width and / or pulse interval is adjusted based on target environment information relating to a target environment.

3. The control device according to claim 2, wherein the generation unit generates the control signal in which the pulse width and / or pulse interval is adjusted based on a target soil moisture profile of a target soil moisture content.

4. The control device according to claim 3, wherein the generation unit generates the control signal based on the target soil moisture profile for one or each of a plurality of locations in the soil.

5. The control device according to claim 3, wherein the target soil moisture profile is obtained in response to a user operation.

6. The control device according to claim 3, wherein the generation unit generates the control signal for irrigating so that the soil moisture amount predicted by a simulator that predicts soil moisture amount matches the target soil moisture profile.

7. The control device according to claim 6, wherein the generation unit generates the next control signal based on an error between the observed soil moisture content, which is an observed value of the soil moisture content after irrigation performed in accordance with the control signal, and the target soil moisture profile.

8. The control device according to claim 7, wherein the generating unit updates physical parameters of the simulator so as to reduce the error in the observed soil moisture content.

9. The control device according to claim 8, wherein the generating unit sets the physical parameters in an initial setting such that the error between the soil moisture content predicted by the simulator and the observed soil moisture content is reduced.

10. The control system of claim 3, wherein the target soil moisture profile defines upper and / or lower limits of a range of target soil moisture contents.

11. The control device according to claim 2, wherein the generation unit generates the control signal in which the pulse width and / or pulse interval is adjusted based on a target water stress profile of a target water stress value for a plant.

12. The control device according to claim 11, wherein the target water stress profile is obtained in response to a user operation.

13. The control device according to claim 11, wherein the generation unit generates the control signal for irrigating so that a water stress value estimated using soil moisture content predicted by a simulator that predicts soil moisture content matches the target water stress profile.

14. The control device according to claim 13, wherein the generation unit generates the next control signal based on an error between an observed water stress value, which is an observed value of water stress after irrigation performed in accordance with the control signal, and the target water stress profile.

15. The control device according to claim 14, wherein the generation unit updates physical parameters of the simulator so as to reduce the error in the observed water stress value.

16. The control device according to claim 1, wherein the generation unit generates the control signal based on a weather forecast.

17. The control device according to claim 1, wherein the generation unit generates a plurality of the control signals for controlling a plurality of irrigation systems.

18. The control device according to claim 1, wherein the generating unit generates other control signals for controlling the environment.

19. A control method comprising generating a control signal having a variable pulse width and / or a variable pulse interval as a control signal for controlling irrigation.

20. A program that causes a computer to function as a generating unit that generates a control signal having a variable pulse width and / or pulse interval as a control signal for controlling irrigation.

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