Light intensity control device for duckweed multi-layer culture shelf

Abstract

The utility model discloses a kind of Lemna multilayer culture frame light intensity regulation and control devices, it includes: including frame body, multiple layer culture container being set on the frame body, light environment perception module, intelligent control module and plant lamp execution module;The light environment perception module is used to perceive the illumination information of each layer culture container, the intelligent control module is used to handle the data of light environment perception module and output control signal, the plant lamp execution module is used to adjust the illumination of each layer culture container according to control signal.The utility model realizes the accurate regulation and control of each layer illumination of multilayer frame body as needed, structure is clear, response is sensitive, not only effectively overcome the problem of uneven illumination in three-dimensional cultivation, but also substantially reduce the light supplement energy consumption while guaranteeing the photosynthetic demand of Lemna, provide practical and reliable equipment support for the intelligent management of Lemna greenhouse and multilayer production.

Description

Technical Field

[0001] This utility model belongs to the field of duckweed cultivation and relates to a light intensity control device for a multi-layer duckweed cultivation rack, and more particularly to a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light sensing. Background Technology

[0002] Duckweed is a rapidly growing aquatic plant with high protein content and broad application prospects. To increase its yield per unit area, multi-layered three-dimensional cultivation racks are often used in controlled-environment agriculture for intensive production in glass greenhouses. However, the multi-layered structure leads to severe shading in the middle and lower cultivation areas, resulting in extremely uneven distribution of natural light, which significantly affects the photosynthetic efficiency and biomass accumulation of duckweed. Currently used timed or fixed-intensity supplemental lighting strategies are inflexible and difficult to dynamically adjust according to actual light conditions. This not only results in low light energy utilization efficiency and serious energy waste, but also fails to maintain stable and optimal light conditions for each cultivation layer. Existing technologies lack intelligent supplemental lighting devices that can sense the light intensity of different layers in real time and achieve precise on-demand light adjustment based on multi-node sensor data. Especially when there is strong natural light in the middle and upper layers, traditional methods cannot automatically reduce the supplemental lighting intensity in the corresponding areas, resulting in ineffective energy loss and severely restricting the photosynthetic efficiency and energy economy of duckweed production. Therefore, there is an urgent need for a highly efficient and energy-saving supplementary lighting solution that can automatically adjust the supplementary lighting intensity of each layer based on real-time data collection and set thresholds through a dynamic light-sensing control mechanism, reduce or turn off artificial lighting when there is sufficient sunlight, thereby achieving precise layered light control, stabilizing the lighting environment and significantly reducing total energy consumption. Utility Model Content

[0003] To overcome the aforementioned shortcomings of existing multi-layer duckweed cultivation racks, the inventor conceived and fabricated a light intensity control device for multi-layer duckweed cultivation racks based on the synergy of vision and light sensing. This device solves the problem of severe shading in the middle and lower cultivation areas of multi-layer duckweed cultivation racks, resulting in extremely uneven distribution of natural light and significantly affecting the photosynthetic efficiency and biomass volume of duckweed. Specifically, this utility model includes the following technical solutions.

[0004] A light intensity control device for a multi-layer duckweed cultivation rack is a light intensity control device based on the synergy of vision and light sensing. It includes: a frame, a multi-layer cultivation container set on the frame, a light environment sensing module, an intelligent control module (preferably an industrial computer), and a plant light execution module.

[0005] The light environment sensing module is used to sense the light information of each layer of aquaculture containers, the intelligent control module is used to process the data from the light environment sensing module and output control signals, and the plant light execution module is used to adjust the light of each layer of aquaculture containers according to the control signals.

[0006] In one embodiment, the light environment sensing module includes a camera and a PAR sensor disposed on each layer of the aquaculture container. The camera is used to capture the light spot distribution image of each layer of the aquaculture container, and the PAR sensor is used to measure the photosynthetically active radiation at each location of each layer of the aquaculture container.

[0007] Preferably, an RGB camera is used. An RGB camera can capture color images, including detailed information on the three channels of red (R), green (G), and blue (B), which is suitable for processing light spot distribution images under natural lighting.

[0008] Preferably, the aforementioned PAR sensors are multiple and arrayed above the culture water surface of each layer of the aquaculture container to measure the photosynthetically active radiation at each location in the aquaculture container.

[0009] Preferably, the PAR sensor is 3-6 cm away from the culture water surface of the culture container. In this embodiment, the PAR sensor is selected to be 5 cm away from the culture water surface of the culture container.

[0010] In one embodiment, the above-mentioned plant light execution module includes a cylindrical full-spectrum plant light disposed above each layer of the cultivation container and a PWM dimming controller. The PWM dimming controller is connected to the intelligent control module for data transmission and is used to adjust the light intensity output of the cylindrical full-spectrum plant light.

[0011] Preferably, a light reflecting mechanism installed on the frame is provided above the above-mentioned breeding container, which is used to reflect the light emitted by the cylindrical full-spectrum plant lamp to the corresponding position;

[0012] The light reflecting mechanism includes two first mirror plates hinged to the frame. The two first mirror plates are symmetrically arranged around the cylindrical full-spectrum plant lamp. A tension spring and a stop bar are provided between the upper side of the two first mirror plates and the frame. The tension spring is used to provide an upward flipping force, and the stop bar is used to restrict the first mirror plate to a horizontal state when it contacts the first mirror plate. The light reflecting mechanism also includes a drive assembly for driving the first mirror plates to flip downward.

[0013] Preferably, a buffer pad is provided at the contact point between the abutment and the first mirror plate to prevent the first mirror plate from breaking when impacted.

[0014] In one embodiment, the two first mirror plates are hinged to the frame via the same round rod. This method allows for more significant adjustment of the size of the reflected light.

[0015] In another embodiment, a second mirror plate is fixed at the middle position of the frame, and the two hinge points between the first mirror plate and the frame are located at the two side edges of the second mirror plate.

[0016] The aforementioned drive assembly includes two vertical mounting plates mounted on the frame, with a rotating shaft rotatably mounted between the two vertical mounting plates. A motor for driving the rotating shaft is fixed on one of the vertical mounting plates, and at least one pair of push blocks are fixed on the rotating shaft. When the motor operates at a set angle, the push blocks push the first mirror plate to flip, thereby adjusting the light reflection angle.

[0017] The motor can be a stepper motor or a servo motor. The motor speed can be controlled within a set slow speed range to avoid the first mirror plate flipping too fast. The downward flip angle of the first mirror plate is 5°-15°, which can be set according to actual needs.

[0018] Preferably, the drive assembly further includes two linear drive components mounted on the frame, and the two vertical mounting plates are respectively fixed to the telescopic ends of the two linear drive components. The linear drive components can be cylinders, rod motors, etc.

[0019] When the telescopic end of the linear drive component extends, two push blocks can be used to push and flip the two first mirror plates downwards simultaneously, so as to synchronously adjust the angle of the two first mirror plates, so that the two mirror plates reflect the light from the cylindrical full-spectrum plant lamp to the middle area of ​​the cultivation container.

[0020] This utility model presents a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light sensing. It realizes precise control of light intensity for each layer of the multi-layer rack as needed. The device has a clear structure and a sensitive response. It not only effectively overcomes the problem of uneven light intensity in three-dimensional cultivation, but also significantly reduces the energy consumption of supplemental lighting while ensuring the photosynthetic needs of duckweed. It provides practical and reliable equipment support for the intelligent management of greenhouse and multi-layer duckweed production.

[0021] The light reflection mechanism dynamically reflects light from cylindrical full-spectrum plant lights to shaded or low-light areas in the duckweed cultivation zone, significantly improving the uniformity of lighting in multi-layered structures. It can rotate the mirror panel unilaterally or simultaneously, precisely projecting light onto the side or central dark areas, avoiding hotspot and dark area differences caused by natural light obstruction, ensuring balanced light intensity distribution across all cultivation containers, thereby improving the photosynthetic efficiency and biomass accumulation of duckweed. Simultaneously, it allows the use of low-power plant lights combined with direct and reflected light to achieve the target light intensity, reducing supplemental lighting energy consumption in the middle and lower layers by more than 30%, optimizing energy utilization and reducing electricity waste. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of a structural embodiment of the light intensity control device for a multi-layer duckweed culture rack based on the synergy of vision and light perception according to the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of a culture container in an embodiment of a light intensity control device for a multi-layer duckweed culture rack based on the synergy of vision and light perception.

[0024] Figure 3 This is a three-dimensional structural diagram of the light reflection mechanism in an embodiment of a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light perception.

[0025] Figure 4 This is a semi-sectional three-dimensional structural diagram of the light reflection mechanism in the first embodiment of a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light perception.

[0026] Figure 5 This is a schematic diagram of a half-section planar structure of the light reflection mechanism in a first embodiment of a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light perception.

[0027] Figure 6 This is a schematic diagram of the unadjusted planar structure of the light reflection mechanism in a first embodiment of a light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light perception.

[0028] Figure 7 This is a schematic diagram of the first embodiment of the light reflection mechanism in a multi-layer duckweed cultivation rack light intensity control device based on the synergy of vision and light perception, showing the first mirror plate on the adjustment side tilting to a planar structure.

[0029] Figure 8 This is a schematic diagram of the light reflection mechanism in a first embodiment of a light intensity control device for a multi-layer duckweed culture rack based on the synergy of vision and light perception, showing the planar structure of adjusting the first mirror plates on both sides to be tilted equally.

[0030] Figure 9 This is a schematic diagram of the unadjusted planar structure of a second embodiment of a light reflection mechanism in a multi-layer duckweed cultivation rack light intensity control device based on the synergy of vision and light perception. Detailed Implementation

[0031] The light intensity control device for the multi-layer duckweed cultivation rack based on vision and light sensing of this utility model consists of three parts: a light environment sensing module, an intelligent control module, and a plant light execution module. The modules are coupled to form a closed-loop and feedforward composite control.

[0032] The light environment sensing module includes high-precision PAR (photosynthetically active radiation) sensors 4 distributed across the culture water surfaces of each layer of aquaculture containers 2, and cameras 3 facing the culture water surfaces of each layer of aquaculture containers 2. The PAR sensors 4 are used to directly and in real-time measure the photosynthetically active radiation of each water surface, providing quantitative light intensity data; the cameras 3 are preferably RGB cameras, which are used to continuously capture images of the light spot distribution on the water surface. The cameras 3 are connected to the intelligent control module to provide the light spot distribution image signal.

[0033] The intelligent control module, with a high-performance embedded controller industrial computer 7 as its core, is responsible for receiving and fusing real-time sensor data from multiple sources. It combines the photosynthetically active radiation measured by the real-time PAR sensors 4 of each layer of aquaculture containers 2 with the image recognition results from the camera 3 to calculate the required artificial lighting intensity for the corresponding location of each layer of aquaculture containers 2.

[0034] For example, the intelligent control module can use the OpenCV algorithm library in the field of computer vision to extract the mask of an RGB image. Because the brightness of the sunlit and shadowed areas differs, and therefore corresponds to different color channels, the module can identify the area proportions of each part. Based on the different effective light radiation received by these two parts, the module can detect this difference using sensors. According to a custom light intensity setting, the required light intensity for different areas can be adjusted.

[0035] Extracting a mask from an RGB image using OpenCV is a classic image processing technique. It primarily utilizes color space transformation (e.g., converting RGB to HSV for better separation of hue, saturation, and brightness), thresholding (e.g., using the `inRange` function to set a color range and generate a binary image), and morphological operations (e.g., erosion and dilation to smooth edges). The specific steps include reading the image, defining a threshold range for the target color, applying a mask to generate a binary image, and optionally using contour detection to refine boundaries. This efficiently isolates regions of interest (such as specific objects or color patches), forming an accurate mask for subsequent image segmentation, object tracking, or enhancement applications. This method is computationally efficient and easy to implement, making it a standard tool for introductory computer vision projects.

[0036] In addition, the industrial control computer 7 has data storage and learning functions. It continuously records and stores historical light and light spot distribution image data of different fixed positions of each layer of aquaculture container 2, and associates them with the timestamps of daily time and seasonal months. It analyzes and extracts the periodic light change patterns of specific positions on different dates and months under normal weather conditions, forming a "light time series pattern library".

[0037] The plant light execution module consists of cylindrical full-spectrum plant lights 6 independently arranged in each layer of the cultivation container 2, a high-precision PWM dimming controller (not shown, which can be integrated into the industrial control computer 7), and a light reflection mechanism 5. The PWM dimming controller receives adjustment signals from the industrial control computer 7 and adjusts the light intensity output of each layer of cylindrical full-spectrum plant lights 6 and the operation of the light reflection mechanism 5. The light reflection mechanism 5 can adjust the angle of light reflection based on the PAR measurement value measured by the PAR sensor 4 and the image recognition result of the camera 3, thereby adjusting the light intensity at the corresponding position.

[0038] Furthermore, during system initialization or under special weather conditions, this device primarily relies on real-time data from the light environment sensing module for closed-loop feedback control. After long-term operation and learning, the system can automatically retrieve predicted light intensity and spot distribution data for each layer from the "Light Illumination Timing Pattern Library" based on the current date and time, and pre-set supplementary lighting strategies for each layer accordingly. Real-time sensors are only activated for correction and compensation when there is a significant deviation between the real-time detection data and the predicted pattern, thereby reducing reliance on real-time sensing in most normal weather conditions and lowering system power consumption and computational load.

[0039] For the sake of simplicity, the term "the light intensity control device for multi-layer duckweed culture rack based on the synergy of vision and light perception" is sometimes referred to as "this device" in this article. They have the same meaning and can be used interchangeably.

[0040] The technical solution of this utility model will now be described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the implementation methods of this application, and not all of them; and the structures shown in the accompanying drawings are merely illustrative and do not represent a physical object. It should be noted that all other embodiments obtained by those skilled in the art based on these embodiments of this utility model are within the scope of protection of this application.

[0041] The terms “comprising,” “including,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. This is something that those skilled in the art will understand.

[0042] See Figure 1 and Figure 2 The present invention relates to a multi-layer duckweed cultivation rack light intensity control device based on the synergy of vision and light sensing, comprising: a frame 1, a cultivation container 2, a light reflection mechanism 5, a camera 3, a PAR sensor 4, an industrial control computer 7, and a cylindrical full-spectrum plant lamp 6. The frame 1 is the main structure of the device. The cultivation container 2, the light reflection mechanism 5, the camera 3, the PAR sensor 4, the industrial control computer 7, and the cylindrical full-spectrum plant lamp 6 are all integrated on the frame 1. The cultivation container 2 can be configured in multiple layers as needed. In this embodiment, the cultivation container 2 is configured in three layers and is fixed to the frame 1. Each layer of the cultivation container 2 contains a duckweed cultivation area, forming a three-dimensional production unit.

[0043] See Figure 4 and Figure 5The cylindrical full-spectrum plant light 6 is a full-spectrum plant light, and is a tube light that emits light from all directions at 360°. One is independently installed above each layer of cultivation containers 2, mounted on the frame 1. Each cylindrical full-spectrum plant light 6 is connected to the industrial control computer 7 via a PWM dimming controller. For the sake of the overall neat appearance of the device, the PWM dimming controller is integrated into the industrial control computer 7, enabling independent and precise control of the light intensity of each layer. The PWM dimming controller has multi-channel independent output capability, with each channel corresponding to one layer of cylindrical full-spectrum plant light 6. It receives dimming commands from the industrial control computer 7 to achieve stepless dimming from 0% to 100%.

[0044] See Figure 2 The PAR sensor 4 is a high-precision photosynthetically active radiation probe, which is installed 3-6 cm above the water surface of each layer of culture container 2 via a crossbar, preferably 5 cm. Specifically, the crossbar is fixed to the upper side of the culture container 2, and the PAR sensor 4 is fixed on the crossbar. The crossbar is relatively narrow to avoid casting shadows on the cylindrical full-spectrum plant lamp 6 that shines into the duckweed culture area. The PAR sensor 4 is used to monitor the actual photosynthetically active radiation at each position of each layer of culture container 2 in real time. There are multiple PAR sensors 4 in each layer, which are distributed in an array.

[0045] See Figure 1 The camera 3 is installed on the frame 1 above the corresponding layer of aquaculture container 2, and its field of view covers the duckweed cultivation area of ​​aquaculture container 2. It is used to continuously collect images of the distribution of light spots on the water surface of each layer, identify the distribution of natural light, and transmit the collected image information to the industrial control computer 7.

[0046] See Figure 1 The industrial control computer 7 can be installed on one side of the frame 1. The industrial control computer 7 acquires the PPFD data of the PAR sensor 4 and the image information collected by the camera 3 in real time, and uses it to control the operation of the cylindrical full-spectrum plant lamp 6 and the light reflection mechanism 5 to adjust the light intensity of each area of ​​the duckweed cultivation area in the cultivation container 2.

[0047] See Figure 1 The light reflection mechanism 5 is located on the upper side of the culture container 2. If the light intensity of the uppermost culture container 2 reaches the expected intensity, the light reflection mechanism 5 may not be installed on it. The light reflection mechanism 5 is used to reflect the light emitted by the cylindrical full-spectrum plant lamp 6 onto the duckweed cultivation area of ​​the culture container 2 to increase the light intensity of a local area of ​​the culture container 2. If the light intensity of a certain area of ​​the culture container 2 (referring to the side area or middle area parallel to the length direction of the cylindrical full-spectrum plant lamp 6) is weak, the light reflection angle can also be adjusted to enhance the light intensity of the corresponding side area or middle area.

[0048] In a preferred embodiment, see Figures 3 to 5The light reflecting mechanism 5 includes two first mirror plates 51 hinged to the frame 1. The two first mirror plates 51 are hinged together to a round rod, and are symmetrically arranged in the plane of the cylindrical full-spectrum plant light 6. A tension spring 52 and a stop rod 53 are installed between the upper side of each first mirror plate 51 and the frame 1. The tension spring 52 applies an upward force to the first mirror plate 51, while the stop rod 53 limits the upward rotation angle of the first mirror plate 51, further restricting the maximum upward rotation angle of the first mirror plate 51. This maximum angle is such that the first mirror plate 51 is in a horizontal state. (See [reference]). Figure 6 In this state, the two first mirror plates 51 can uniformly reflect the light emitted by the cylindrical full-spectrum plant lamp 6 into the duckweed cultivation area of ​​the cultivation container 2, thereby increasing its overall light intensity.

[0049] In another preferred embodiment, see Figure 9 The difference from the above embodiment is that a fixed second mirror plate 58 is added between the two first mirror plates 51. The hinge points of the two first mirror plates 51 and the frame 1 are respectively located at the two side edges of the second mirror plate 58, so that the first mirror plate 51 and the second mirror plate 58 are as close as possible.

[0050] See Figures 3 to 5 A drive assembly for adjusting the angle of two first mirror plates 51 is installed on the frame 1. It includes two linear drive components 57 fixed to the frame 1. The two linear drive components 57 are located on the frame 1 near its side edge. The linear drive components 57 can be cylinders, rod motors, etc. The telescopic ends of the two linear drive components 57 are equipped with vertical mounting plates. A rotating shaft 55 is rotatably mounted between the two vertical mounting plates. A motor 54 that drives the rotating shaft 55 to rotate is fixed on one of the vertical mounting plates. The motor 54 and the linear drive components 57 are controlled by an industrial control computer 7. At least one pair of push blocks 56 are fixed on the rotating shaft 55. Preferably, there are two pairs of push blocks 56. The outer end of the push block 56 corresponds to the first mirror plate 51 on its corresponding side and contacts the mirror plate 51.

[0051] During operation, the user sets the target light intensity range for duckweed growth in each layer of the aquaculture container 2 via the industrial control computer 7. The PAR sensor 4 provides real-time feedback on the light intensity in each layer of the aquaculture container 2, and the camera 3 simultaneously identifies the distribution area and location of natural light spots. The industrial control computer 7 integrates the light intensity data and image analysis results to adjust the output of the PWM dimming controller: when certain parts of a layer are not exposed to natural light and the light intensity is lower than the target, the power of the cylindrical full-spectrum plant lamp 6 corresponding to the unexposed area is increased; when a certain area of ​​a layer is directly exposed to natural light, the light intensity of the plant lamp in the corresponding area should be reduced to ensure that the overall light intensity distribution is uniform and does not exceed the target upper limit.

[0052] If the light intensity in the side or middle areas is insufficient due to the inability of natural light to directly illuminate them, resulting in shadows, the cylindrical full-spectrum plant light 6 can be turned on. Under the illumination of the cylindrical full-spectrum plant light 6, the angle of the corresponding first mirror plate 51 can be adjusted by the drive component so that the first mirror plate 51 reflects the light from the cylindrical full-spectrum plant light 6 to the corresponding shadow area. The shadow area will be affected by both the light directly illuminating the cylindrical full-spectrum plant light 6 and the light reflected by the first mirror plate 51. Therefore, a low-power cylindrical full-spectrum plant light 6 can be used to evenly distribute the overall light intensity of the cultivation container 2.

[0053] If the light intensity is weak on one side of the cultivation container 2, the first mirror plate 51 on the other side can be flipped and tilted downwards to reflect the light from the cylindrical full-spectrum plant lamp 6 onto that side, thereby enhancing the light intensity. Specifically, the motor 54 drives the pusher block 56 on the corresponding side to push and flip the first mirror plate 51 downwards (it should be noted that the flipping of the first mirror plate 51 will not affect the original light intensity of the cultivation container 2), so that the first mirror plate 51 reflects the light from the cylindrical full-spectrum plant lamp 6 onto the side area that was previously shaded, and the tension spring 52 is stretched. See [link to relevant documentation]. Figure 7 When the motor 54 runs to the initial position, the first mirror plate 51 will flip upward due to the force of the tension spring 52 and eventually return to its original state (horizontal).

[0054] If the light intensity in the middle area of ​​the cultivation container 2 is weak, with the push blocks 56 on both sides of the rotating shaft 55 horizontally symmetrical, the telescopic end of the linear drive component 57 is extended. The push blocks 56 on both sides push and flip the two first mirror plates 51 downwards simultaneously, causing the two first mirror plates 51 to reflect the light from the cylindrical full-spectrum plant lamp 6 to the middle area, and stretching the tension springs 52 on both sides. See [link to relevant documentation]. Figure 8 When the linear drive component 57 retracts its telescopic end, the first mirror plates 51 on both sides will flip upward due to the force of the tension spring 52 and eventually return to their original state (horizontal).

[0055] This device enables precise control of light intensity across multiple layers of the multi-layered frame. With a clear structure and sensitive response, it not only effectively overcomes the problem of uneven lighting in vertical cultivation but also significantly reduces supplemental lighting energy consumption while ensuring the photosynthetic needs of duckweed. It provides practical and reliable equipment support for the intelligent management of greenhouse and multi-layered production of duckweed.

[0056] The above provides a detailed description of the light intensity control device for a multi-layer duckweed cultivation rack based on the synergy of vision and light sensing of this utility model. The description of the above embodiments is only for the purpose of helping to understand the inventive concept of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are only the principles of this utility model. Various changes and modifications can be made to this utility model without departing from the spirit and scope of this utility model, and all such changes and modifications fall within the scope of protection of this utility model as claimed. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A light intensity control device for a multi-layer duckweed culture rack, characterized in that, It includes a frame, a multi-layered aquaculture container mounted on the frame, a light environment sensing module, an intelligent control module, and a plant light execution module; The light environment sensing module is used to sense the light information of each layer of aquaculture containers, the intelligent control module is used to process the data from the light environment sensing module and output control signals, and the plant light execution module is used to adjust the light of each layer of aquaculture containers according to the control signals.

2. The light intensity control device for the multi-layer duckweed culture rack as described in claim 1, characterized in that, The light environment sensing module includes a camera and a PAR sensor installed on each layer of the aquaculture container. The camera is used to capture the light spot distribution image of each layer of the aquaculture container, and the PAR sensor is used to measure the photosynthetically active radiation at each location of each layer of the aquaculture container.

3. The light intensity control device for the multi-layer duckweed culture rack as described in claim 2, characterized in that, The PAR sensors are multiple and arranged in an array above the water surface of each layer of aquaculture containers.

4. The light intensity control device for the multi-layer duckweed culture rack as described in claim 3, characterized in that, The PAR sensor is located 3-6 cm above the water surface in the culture container.

5. The light intensity control device for a multi-layer duckweed culture rack as described in claim 1, characterized in that, The plant light execution module includes a cylindrical full-spectrum plant light installed above each layer of the cultivation container and a PWM dimming controller. The PWM dimming controller is connected to the intelligent control module for data transmission and is used to adjust the light intensity output of the cylindrical full-spectrum plant light.

6. The light intensity control device for a multi-layer duckweed culture rack as described in claim 5, characterized in that, Above the aquaculture container is a light reflection mechanism installed on the frame, which is used to reflect the light emitted by the cylindrical full-spectrum plant lamp to the corresponding position; The light reflection mechanism includes two first mirror plates hinged to the frame. The two first mirror plates are symmetrically arranged around the cylindrical full-spectrum plant lamp. A tension spring and a stop bar are provided between the upper side of the two first mirror plates and the frame. The tension spring is used to provide an upward flipping force, and the stop bar is used to restrict the first mirror plate to a horizontal state when it contacts the first mirror plate. The light reflection mechanism also includes a drive component for driving the first mirror plate to flip downwards.

7. The light intensity control device for a multi-layer duckweed culture rack as described in claim 6, characterized in that, The two first mirror plates are hinged to the frame via the same round rod.

8. The light intensity control device for a multi-layer duckweed culture rack as described in claim 6, characterized in that, A second mirror plate is fixed at the middle of the frame, and the two hinge points between the first mirror plate and the frame are located at the two side edges of the second mirror plate.

9. The light intensity control device for a multi-layer duckweed culture rack as described in any one of claims 6-8, characterized in that, The drive assembly includes two vertical mounting plates mounted on the frame, with a rotating shaft rotatably mounted between the two vertical mounting plates. A motor that drives the rotating shaft to rotate is fixed on one of the vertical mounting plates, and at least one pair of push blocks are fixed on the rotating shaft. When the motor runs at a set angle, the push blocks push the first mirror plate to flip to adjust the light reflection angle.

10. The light intensity control device for a multi-layer duckweed culture rack as described in claim 9, characterized in that, The drive assembly also includes two linear drive components mounted on the frame, and the two vertical mounting plates are respectively fixed to the telescopic ends of the two linear drive components.

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