JP6940642B2 - Lighting control devices, lighting control methods, and lighting control programs for plant factories - Google Patents

Description

The present invention relates to a lighting control device, a lighting control method, and a lighting control program for a plant factory.

In recent years, a plant factory for cultivating plants indoors using artificial light and a solution has been put into practical use. A system using an LED as a light source for plant growth has been developed in a closed-type plant factory that shields sunlight (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2010-178682

The size of plants changes from the state of seedlings to the state at the time of harvest, but the lighting is fixed in the plant factory. Therefore, for example, even if the light receiving amount of each plant is uniform in the state of seedlings, when the plant grows large at the time of harvesting, the light receiving amount may vary among a plurality of plants. Further, even within one plant, the amount of light received may vary depending on the site.

If the amount of light received is insufficient, the rate of photosynthesis will decrease, which will adversely affect the growth of plants. As a result, it may be difficult to homogenize the growth state of plants and stabilize the yield in the entire food factory.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a lighting control device, a lighting control method, and a lighting control program that suppress variations in the amount of light received by plants in a plant factory. be.

In order to achieve the above object, one aspect of the present invention is a lighting control device for a plant factory, in which a receiving unit that receives a carbon dioxide concentration measured by a sensor arranged around the plant and the carbon dioxide concentration. A determination unit for determining the growth stage of the plant, and a control unit for controlling at least one of the irradiation region of the illumination for irradiating the plant with artificial light and the illuminance according to the growth stage. ..

One aspect of the present invention is a lighting control method performed by a lighting control device for a plant factory, which uses a receiving step of receiving a carbon dioxide concentration measured by a sensor arranged around a plant and the carbon dioxide concentration. A determination step for determining the growth stage of the plant and a control step for controlling at least one of the irradiation region and the illuminance of the illumination for irradiating the plant with artificial light are performed according to the growth stage.

One aspect of the present invention is a lighting control program that causes a computer to function as the lighting control device.

According to the present invention, it is possible to provide a lighting control device, a lighting control method, and a lighting control program that suppress variations in the amount of light received by plants in a plant factory.

It is an overall block diagram which shows the structure of the lighting control system of embodiment of this invention. It is a figure which shows an example of a control table. It is explanatory drawing for demonstrating the angle of illumination. It is explanatory drawing for demonstrating the angle of illumination. It is a flowchart which shows the operation of a lighting control device. This is a hardware configuration example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Configuration of lighting control system)
FIG. 1 is a diagram showing an overall configuration of the lighting control system of the present embodiment. First, the cultivation shelf 9 of the plant factory will be described. The plant factory of the present embodiment is a closed type plant factory in which plants are cultivated by using artificial light, and includes a plurality of cultivation shelves 9 as shown in the figure.

A plurality of plants 8 are cultivated on the cultivation shelf 9. The cultivation shelf 9 includes a lighting unit 91. In the lighting unit 91, a plurality of lights (light sources) 92 are installed on the side facing the plant 9. The plant 8 grows by photosynthesis when it is irradiated with light from the illumination 92. In this embodiment, an LED (Light Emitting Diode) is used for the lighting 92, but the lighting is not limited to this. A fluorescent lamp (FL: Fluorescent Lamp) or the like may be used for the illumination 12. The lighting unit 91 of the present embodiment is a movable member whose vertical or orientation can be adjusted by the driving device 2. As a result, the height and angle of the illumination 92 of the illumination unit 91 can be adjusted.

The lighting control system of the present embodiment includes at least one sensor 1, a driving device 2, and a lighting control device 3. The sensor 1 is arranged around the plant 8 in the cultivation shelf 9 and measures the CO2 (carbon dioxide) concentration. In the illustrated example, one sensor 1 is arranged on each of the left and right walls of the cultivation shelf 9. The sensor 1 measures the CO2 concentration at a predetermined timing (for example, every n minutes) and transmits the measurement result to the control device 3. The sensor 1 may transmit the measurement result wirelessly or by wire.

The drive device 2 changes the arrangement (position) such as the height and angle of the lighting 92 and changes the illuminance of the lighting 92 according to the instruction from the lighting control device 3. In the illustrated example, the drive device 2 changes the arrangement of the illumination 92 by changing the arrangement of the illumination unit 91.

The lighting control device 3 controls the lighting 92 of the cultivation shelf 9 by using the driving device 2. The illustrated lighting control device 3 includes a receiving unit 31, a determination unit 32, a control unit 33, and a control table 34. The receiving unit 31 receives the CO2 concentration (measurement result) transmitted from the sensor 1.

The determination unit 32 determines the growth stage (growth state) of the plant 8 based on the CO2 concentration received from the sensor 1. When a plurality of sensors 1 are installed on the cultivation shelf 9 and CO2 concentrations are received from the plurality of sensors 1, the determination unit 32 determines using, for example, the average value of the CO2 concentrations of the plurality of sensors 1.

In the present embodiment, the determination unit 32 determines which of the three growth stages (stages) the plant 8 is in. The first stage is the planting (seedling raising) stage, the second stage is the vegetative growth stage, and the third stage is the reproductive growth stage. The planting stage is a state in which the seedlings are planted on the cultivation shelf 9 and the seedlings are grown. The vegetative growth stage is the time when a plant makes vegetative organs such as stems, leaves and roots. The reproductive growth stage is the time when flower buds are produced, flowers bloom, and fruits are produced. The growth stage is not limited to three stages, and may be two stages or four or more stages.

Plant 8 absorbs CO2 by photosynthesis. The amount of CO2 absorbed depends on the size (volume) of the plant 8 when the conditions of the amount of light are the same. That is, at the planting stage, the plant 8 is small and the amount of CO2 absorbed is small. On the other hand, the fruit-bearing reproductive and growing plant 8 is large and absorbs a large amount of CO2. In the cultivation shelf 9, in order to keep the CO2 concentration constant, when the CO2 concentration falls below a predetermined threshold value, CO2 is supplied from the CO2 supply device (not shown).

For example, the determination unit 32 calculates the supply interval (interval) from the supply of CO2 to the supply of the next CO2 from the time-series data of the CO2 concentration received from the sensor 1, and uses the supply interval to calculate the supply interval (interval) of the plant. The growth stage may be determined. Since the CO2 concentration rises sharply when CO2 is supplied, the CO2 supply timing and supply interval can be specified by referring to the time-series data of the CO2 concentration. Specifically, when the supply period is long, it can be estimated that the absorption rate of CO2 by the plant 8 is slow and the volume of the plant 8 is small. On the other hand, when the supply interval is long, it can be estimated that the absorption rate of CO2 by the plant 8 is high and the volume of the plant 8 is large. The determination unit 32 determines that the planting stage is in the supply interval when the supply interval is equal to or greater than the first threshold value, and determines that the vegetative growth stage is in the case where the supply interval is less than the first threshold value and is greater than or equal to the second threshold value. If it is less than the second threshold value, it is determined to be in the reproductive growth stage. In this case, the first threshold value is a value larger than the second threshold value.

The determination unit 32 may determine the growth stage of the plant 8 by using the absorption rate of CO2 (the slope of the graph showing the relationship between the CO2 concentration and time). In this case, the determination unit 32 determines that the planting stage is in the case where the absorption rate is less than the third threshold value, and determines that the vegetative growth stage is in the case where the absorption rate is equal to or higher than the third threshold value and less than the fourth threshold value. When the supply interval is equal to or greater than the fourth threshold value, it is determined to be in the reproductive growth stage. In this case, the third threshold value is smaller than the fourth threshold value.

Further, the determination unit 32 may determine the growth stage of the plant 8 by using the number of times of CO2 supply in a predetermined period. In this case, the determination unit 32 determines that the planting stage is in the case where the number of times of supply is less than the fifth threshold value, and determines that it is in the vegetative growth stage when the number of times of supply is equal to or more than the fifth threshold value and less than the sixth threshold value. When the number of feeds is equal to or greater than the sixth threshold value, it is determined that the plant is in the reproductive growth stage. In this case, the fifth threshold value is smaller than the sixth threshold value. The first threshold value to the sixth threshold value are stored in a storage unit (not shown).

The control unit 33 controls at least one of the irradiation region and the illuminance of the illumination 92 according to the growth stage determined by the determination unit 32. Specifically, the control unit 32 controls the illumination 92 using the control table 34. In the present embodiment, the control unit 32 controls the irradiation region by controlling at least one of the height and the angle (irradiation angle) of the illumination 92.

FIG. 2 is a diagram showing an example of the control table 34. The control table 34 is a table in which the growth stage is associated with a control pattern including at least one of the height, angle, and illuminance of the illumination. The illustrated control table 34 includes a lighting arrangement (height, angle) and an illuminance as control patterns. The height may be, for example, the height from the cultivation panel on which the plant 8 is planted, or the height from the bottom of the cultivation shelf 9.

Plant 8 grows and grows as the growth stage progresses. Therefore, in the control table 34, the arrangement parameter of the illumination 92 is set so that the irradiation area becomes larger as the growth stage progresses. Specifically, the irradiation area becomes larger by raising the position of the illumination. Further, the irradiation area may be increased by changing the direction (angle) of the illumination.

In the illustrated control table, the arrangement position of the illumination 92 in the vegetative growth stage is set higher than the arrangement position of the illumination 92 in the planting stage in consideration of the fact that the plant grows (spreads) due to growth. Specifically, when the height of the planting stage is N1 and the height of the vegetative growth stage is M1, the values of N1 and M1 are set so that N1 <M1. In the illustrated example, N1 = 20 cm and M1 = 30 cm. As a result, the irradiation area of the vegetative growth stage can be expanded from the irradiation area of the planting stage.

Here, the angle N2 in the planting stage and the angle M2 in the growing stage are both 0 degrees, and the irradiation area is changed using only the height. However, the angle M2 of the vegetative growth stage may be set larger than the angle N2 of the planting stage to make the irradiation area of the vegetative growth stage larger than the irradiation area of the planting stage.

Regarding the illuminance, the illuminance at the vegetative growth stage is set higher than the illuminance at the planting stage. Specifically, the illuminance N3 in the planting stage is set to be larger than the illuminance M3 in the vegetative growth stage. In the illustrated example, N3 = 400 μmol and M3 = 500 μmol.

In the reproductive growth stage, the illumination angle is changed in the illustrated example in order to make the irradiation area larger than the irradiation area in the vegetative growth stage. For example, in the reproductive growth stage, the plant 8 bears fruit, but in fact, it may be located at a position away from the center of the stem of the plant 8. Therefore, the irradiation area is enlarged and the angle (tilt) of the illumination 92 is controlled in order to shift the irradiation area.

3A and 3B are explanatory views for explaining the angle of the illumination 92. FIG. 3A shows the illumination 92 at an angle of 0 degrees. Here, the angle at which the illumination 92 is arranged horizontally and illuminates directly below is set to 0 degree. In this case, the irradiation area 41 becomes larger according to the height of the illumination 92, but the portion of the plant (strawberry fruit in the illustrated example) that has grown so far from the cultivation shelf 9 is out of the irradiation area 41. That is, photosynthesis is not performed because the part of the plant outside the cultivation shelf 9 is not exposed to light. As a result, it is difficult to homogenize the growing state of the plant and stabilize the yield.

FIG. 3B shows illumination at an angle of 15 degrees. This angle is the elevation angle from horizontal to upward. By tilting the illumination 92 from the horizontal at a predetermined angle, the irradiation area 42 expands toward the outside of the cultivation shelf 9. As a result, the portion of the plant (the portion away from the center of the plant) that has grown so far from the cultivation shelf 9 is also included in the irradiation region 42. That is, light also hits the part of the plant outside the cultivation shelf 9, and photosynthesis is promoted. As a result, the growing state of the plant can be homogenized and the yield can be stabilized.

In the illustrated example, the heights of both the vegetative growth stage and the reproductive growth stage are set to 30 cm, and the irradiation area is changed using only the angle, but the height of the reproductive growth stage is set higher than the height of the vegetative growth stage. Therefore, the irradiation area of the reproductive growth stage may be made larger than the irradiation area of the vegetative growth stage.

Regarding the illuminance, the illuminance at the reproductive growth stage is set higher than the illuminance at the vegetative growth stage. Specifically, the illuminance M3 in the vegetative growth stage is set to be larger than the illuminance L3 in the reproductive growth stage. In the illustrated example, M3 = 500 μmol and L3 = 600 μmol.

(Operation of lighting control device)
FIG. 4 is a flowchart showing the operation of the lighting control device 3. The receiving unit 31 receives the CO2 concentration from the sensor 1 at a predetermined timing (S1). The determination unit 32 determines the growth stage of the plant 8 using the received time-series data of the CO2 concentration (S2). Then, the determination unit 32 determines whether or not the determined growth stage is the same as the previously determined growth stage (S3). If it is the same as the previous growth stage (S3: YES), the process returns to S1 and the subsequent processing is repeated.

When it is different from the previous growth stage (S3: NO), the control unit 33 considers that the plant 8 has advanced to the next stage, and acquires the control pattern corresponding to the growth stage determined in S2 from the control table 34 (S4). ). Then, the control unit 33 transmits a control instruction including the height, angle, and illuminance of the illumination 92 of the acquired control pattern to the drive device 2 (S5). The drive device 2 controls the lighting unit 91 to change the irradiation area to the lighting 92 and changes the illuminance of the lighting 92 according to the control instruction from the lighting control device 3.

(Effect of this embodiment)
The lighting control device 3 for a plant factory of the present embodiment described above uses the receiving unit 31 that receives the carbon dioxide concentration measured by the sensor 1 arranged around the plant 8 and the carbon dioxide concentration of the plant 8. A determination unit 32 for determining the growth stage of the plant 8 and a control unit 33 for controlling at least one of the irradiation region and the illuminance of the illumination 92 for irradiating the plant 8 with artificial light according to the growth stage are provided.

Thereby, in the present embodiment, the variation in the light receiving amount of the plant 8 in the plant factory can be suppressed to the minimum, and the growing state of the plant 8 can be made uniform in the entire food factory. In addition, the yield of plant 8 can be stabilized.

(Hardware configuration)
For the lighting control device 3 described above, for example, a general-purpose computer system as shown in FIG. 5 can be used. The computer system shown is a CPU (Central Processing Unit, processor) 901, a memory 902, a storage 903 (HDD: Hard Disk Drive, SSD: Solid State Drive), a communication device 904, an input device 905, and an output device. 906 and. The memory 902 and the storage 903 are storage devices. In this computer system, each function of the lighting control device 3 is realized by executing the program for the lighting control device 3 loaded on the memory 902 by the CPU 901.

Further, the lighting control device 3 may be mounted on one computer or may be mounted on a plurality of computers. Further, the lighting control device 3 may be a virtual machine mounted on a computer.

The program for the lighting control device 3 can be stored in a computer-readable recording medium such as an HDD, SSD, USB (Universal Serial Bus) memory, CD (Compact Disc), or DVD (Digital Versatile Disc), or via a network. It can also be delivered.

The present invention is not limited to the above-described embodiment and modification, and many modifications can be made within the scope of the gist thereof.

1: Sensor 2: Drive device 3: Lighting control device 31: Receiver 32: Judgment unit 33: Control unit 34: Control table 8: Plant 9: Cultivation shelf 91: Lighting unit 92: Lighting

Claims (5)

Lighting control device for plant factories
A receiver that receives the carbon dioxide concentration measured by sensors placed around the plant,
A determination unit that determines the growth stage of the plant using the carbon dioxide concentration,
A control unit that controls the irradiation area and illuminance of the illumination that irradiates the plant with artificial light according to the growth stage.
A drive unit that changes the height and angle of a movable lighting unit including at least one of the lighting units according to the control of the control unit.
The control unit is a lighting control device characterized by controlling at least one of the height and angle of the lighting to control the irradiation region. The lighting control device according to claim 1.
A control table in which the growth stage is associated with at least one of the height, angle, and illuminance of the illumination is provided.
The control unit is a lighting control device characterized in that the lighting is controlled by using the control table. The lighting control device according to claim 1 or 2.
The lighting control device is characterized in that the lighting is an LED. It is a lighting control method performed by a lighting control device for a plant factory.
A receiving step that receives the carbon dioxide concentration measured by a sensor placed around the plant,
A determination step for determining the growth stage of the plant using the carbon dioxide concentration, and
A control step that controls at least one of the irradiation area and the illuminance of the illumination that irradiates the plant with artificial light according to the growth stage.
A drive step that changes the height and angle of the movable lighting unit provided with at least one of the lights according to the control of the control step.
The control step is a lighting control method comprising controlling at least one of the height and angle of the lighting to control the irradiation area. A lighting control program comprising operating a computer as the lighting control device according to any one of claims 1 to 3.

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