CN206713617U - A kind of control system for acting on hothouse plants growth - Google Patents

Abstract

The utility model relates to a control system acting on the growth of greenhouse plants, comprising a PLC controller, an environment sensing system respectively connected to the PLC controller, an environment regulation system, a data storage unit and a system for man-machine interaction and real-time observation of system information HMI user interface; the utility model has the following advantages: 1) According to different plant attributes and different requirements for light, the distribution ratio of the relative spectrum of red and blue light can be reasonably adjusted; 2) Temperature, humidity, light, carbon dioxide content levels and other intelligence The integration of collection, sensing and control realizes intelligent management; 3) The drip irrigation system and the adjustability of the relative spectral distribution of LED light sources are both energy-saving and environmentally friendly; The ambient light outside the greenhouse and the ambient light outside the greenhouse are monitored to make the management of the ambient light in the greenhouse more refined.

Description

A control system acting on the growth of greenhouse plants

technical field

The utility model relates to the application field of LED lamps in agriculture, in particular to a control system acting on the growth of greenhouse plants.

Background technique

Light, temperature, water, fertilizer, and air are the main environmental factors required for plant growth and development, and each factor is necessary for plant growth and development. Among the five factors, light ranks first, and it mainly affects plant growth through three aspects, namely light distribution, light intensity and photoperiod. Light quality is the wavelength of light radiation, which has regulatory effects on many aspects of plant growth, photosynthesis, morphogenesis, and substance metabolism. In recent years, with the increasing pollution of the atmospheric environment and the increase of hazy weather in the north, the solar radiation received by the earth's surface is decreasing day by day, which seriously affects the growth of crops.

Greenhouse plant cultivation technology provides a scientific, stable and reliable planting technology for modern plant cultivation, and provides a suitable way for people's increasing energy demand. Relevant studies have shown that when the sunlight in the greenhouse is less than 100W/m ² , or the sunshine time is less than 4.5h/day, artificial supplementary light is required. The development of artificial light source instead of sunlight for plant growth lighting supplementary light technology makes greenhouse planting have a broader development prospect. While using artificial light source to supplement light, it can make full use of sunlight, and the combination of the two to achieve a stable and effective lighting state will be an energy-saving and efficient plant supplement light solution.

Plant growth depends on the synthesis of organic matter through photosynthesis in chloroplasts. Studies have shown that the absorption spectrum of chlorophyll a and chlorophyll b, which are crucial to photosynthesis in chloroplasts, is a monochromatic spectrum, and the peak wavelengths of the absorption spectrum are 660nm and 450nm respectively, which is consistent with the fact that LED light sources are monochromatic light sources. And together. Among them, red-orange light is absorbed by plants for photosynthesis in the largest proportion, and the assimilation efficiency of blue-violet light is only about 1/8 of that of red-orange light. Red-orange light plays an important role in the formation of chlorophyll and the synthesis of carbohydrates, accelerates the growth and development of long-day plants, delays the development of short-day plants, and promotes seed germination; blue-violet plays an important role in protein synthesis and accelerates the development of short-day plants , Delaying the development of long-day plants plays an important role, while ultraviolet rays are beneficial to the synthesis of vitamin C. Therefore, it is an energy-saving and efficient feasible method to consider using LED light sources that match the absorption spectrum of chlorophyll a and chlorophyll b as supplementary light for greenhouse plants.

According to the research of M.Johkan.etal, for leaf plants or vegetables, the demand ratio of red and blue light should be satisfied, red: blue <6.8:1, to promote the growth of leaves; The demand ratio of red and blue light should be satisfied, red: blue > 6.8:1, so as to promote the breeding of flowers and fruits. The ratio of red and blue light that does not match the needs of plant growth cannot achieve the best state of promoting plant growth, and may even inhibit plant growth. Therefore, if the ratio of red and blue light of the plant supplementary light source can be adjusted, it can cope with plants with different light requirements, and broaden the scope of application of greenhouse lighting supplementary light.

The modern information society provides a new way of thinking for greenhouse lighting technology: intelligent sensing and intelligent regulation to realize the fine management of plant growth is the trend of the development direction of greenhouse planting.

Contents of the invention

The purpose of this utility model is to overcome the deficiencies of the prior art, to provide an energy-saving and high-efficiency intelligent collection, sensing, regulation, and guarantee of plant lighting with LEDs, supplemented by light quality, temperature and humidity, carbon dioxide content, nutrients, etc. A control system for growing plants in a greenhouse in an optimal growth environment.

In order to achieve the above object, the technical solution provided by the utility model is: including PLC controller, environment sensing system respectively connected with PLC controller, environment control system, data storage unit and real-time observation for human-computer interaction and system information HMI user interface.

Further, the environmental sensing system includes a temperature sensor for testing the outside temperature of the greenhouse, a first temperature and humidity sensor for testing soil temperature and humidity, a second temperature and humidity sensor for testing the temperature and humidity in the greenhouse environment, and a second temperature and humidity sensor for testing the light intensity of the outside world entering the greenhouse environment. The first photosensitive diode, the second photosensitive diode used to test the sum of the light intensity of the outside entering the greenhouse environment and the supplementary light intensity of the LED for plant lighting, and the carbon dioxide sensor to test the carbon dioxide content level in the greenhouse environment.

Further, the environment control system includes LED lighting supplementary light unit, ventilation equipment unit, plant growth nutrition unit, drip irrigation system, atomization system and heat exchange system.

Further, the LED lighting supplementary light unit includes a PWM current drive unit and an LED lighting array unit, and the two are connected through a photocoupler; wherein, the LED lighting array unit includes a red light source module, a blue light source module, a green light source module, and a green light source module. The light source modules are connected in parallel.

Further, the wavelengths of the red light source module, the blue light source module, and the green light source module are 650nm-670nm, 440nm-460nm, and 510nm-530nm, respectively.

Further, the LED lighting array unit is installed 1m to 2m above the plants, and its maximum irradiance is 160W/m ² , and the irradiance of the green light source module should be 20% of the sum of the irradiance of the red and blue light source modules; the relative spectrum of red and blue The distribution ratio is 4:1～9:1.

Further, the LED lighting unit LED lighting array unit is driven by PWM, the frequency of the red, blue and green light source modules are all set to 1kHz-5kHz, the phase difference of the three is 0°, and the duty cycle is 20%-50%.

Further, the ventilation equipment unit is placed above one side of the greenhouse; the drip irrigation system includes a water tank and a water pipe, and the atomization system is connected to the water tank to atomize the liquid water in the water tank to adjust the humidity in the greenhouse environment; the heat exchange system Including a heater and a heat exchanger, the heater heats the water in the water tank according to the demand command, the heated water enters the heat exchanger, and transfers heat to the greenhouse.

Compared with the prior art, this solution has the following advantages and beneficial effects:

1) According to different plant attributes and different requirements for light, the distribution ratio of the relative spectrum of red and blue light can be reasonably adjusted.

2) Intelligent collection, sensing and control of temperature, humidity, light, and carbon dioxide levels are integrated to achieve intelligent management.

3) The drip irrigation system and the adjustability of the relative spectral distribution of each LED light source are energy-saving and environmentally friendly.

4) The ambient light sensor is used to monitor the environment inside and outside the greenhouse in a unified manner, which not only uses the ambient light outside the greenhouse, but also monitors the ambient light outside the greenhouse, so that the management of the ambient light in the greenhouse is more refined.

Description of drawings

Fig. 1 is the functional module schematic diagram of the utility model control system;

Fig. 2 is a schematic diagram of driving regulation of the LED lighting supplementary light unit of the present invention;

Fig. 3 is a schematic diagram of a PWM pulse width dimming used in the LED lighting supplementary light unit of the present invention;

Fig. 4 is a schematic diagram of the functional structure of the light control system of the present invention;

Fig. 5 is a schematic diagram of the system response based on the control algorithm of the utility model;

Fig. 6 is a schematic diagram of the electro-optical conversion efficiency based on the control system of the present invention;

Fig. 7 is a comparison chart of the energy consumption of the utility model adopting the intelligent light control system and the control group.

detailed description

Below in conjunction with specific embodiment the utility model is further described:

Referring to accompanying drawings 1 to 4, a control system for greenhouse plant growth described in this embodiment includes a PLC controller 3, an environmental sensing system 1, an environmental regulation system 2, a data storage unit 4, and an HMI user interface5.

Among them, the PLC controller 3, as the core of the system, connects the other four components to realize information processing and signal regulation. The data storage unit 4 is used to store various data information during system operation. The HMI user interface 5 is used for human-computer interaction to realize real-time information observation and manual intervention.

Environmental sensing system 1 is used for information collection and sensing of environmental state factors, including a temperature sensor 1-1 for testing the outside temperature of the greenhouse, a first temperature and humidity sensor 1-2 for testing soil temperature and humidity, and a temperature and humidity sensor for testing the temperature and humidity in the greenhouse environment. The second temperature and humidity sensor 1-3, the carbon dioxide sensor 1-6 for testing the carbon dioxide content level in the greenhouse environment, the first photosensitive diode 1-4 for testing the light intensity A of the outside world entering the greenhouse environment, and the light intensity for testing the outside world entering the greenhouse environment And the second photodiode 1-5 used for the sum L(t) of LED supplementary light intensity for plant lighting; according to the real-time monitoring of the value L(t), determine whether the LED supplementary light condition is reached and the supplementary light intensity when supplementary light is required The size of L(t)-A, the reference basis for lighting supplementary light adjustment is that the average light quantum flux density received by plants is not less than 20μmolm ^-2 s ^-1 .

The environmental control system 2 includes an LED lighting supplementary light unit 2-1, a ventilation unit 2-2, a plant growth nutrition unit 2-3, a drip irrigation system 2-4, an atomization system 2-5 and a heat exchange system 2-6.

The LED lighting supplementary light unit 2-1 includes a PWM current drive unit 2-1-1 and an LED lighting array unit 2-1-2, which are connected through a photocoupler.

The LED lighting array unit 2-1-2 includes a red light source module 2-1-3 with a wavelength between 650nm and 670nm, a blue light source module 2-1-4 with a wavelength between 440nm and 460nm, and a blue light source module 2-1-4 with a wavelength between 510nm and 530nm. Green light source modules 2-1-5, each module is connected in parallel.

The LED lighting array unit 2-1-2 is installed 1m-2m above the plants, and its maximum irradiance is 160W/m ² . For the red and blue light source modules, the radiation intensity of the two light sources is set to be the same. Through the switch and power regulation mode, the relative spectral distribution ratio of red and blue can be set between 4:1 and 9:1, so as to meet the lighting needs of different plants. The irradiance of the green light source module should meet 20% of the sum of the irradiance of the red and blue light source modules.

The LED lighting supplementary light unit 2-1 is driven by PWM current, and the PWM current driving unit 2-1-1 is controlled by the PLC controller 3 . The pulse width modulation wave realized by the driving unit satisfies the requirements. The frequencies of the red, blue and green light sources are all set to 1KHz-5kHz, the phase difference between the three is 0°, and the duty cycle is adjustable between 20%-50%.

In this way, the control of the indoor LED lighting source part changes according to the change of the external light environment, so that the light quantum flux density received by the plants is a stable value. Furthermore, the ambient light outside the greenhouse can be used as part of the light utilization for plant growth, and the indoor LED lighting supplementary light can be used as a supplementary adjustment. The combination of the two makes full use of energy and is more energy-saving and efficient. In addition, from the system program setting, the required irradiation time is 16h/day, and the day's sunshine time cannot meet this setting, so LED lighting supplementary light is very important.

Ventilation equipment unit 2-2 is placed above the side of the greenhouse to complete the necessary indoor and outdoor gas exchange according to the indoor air content index; plant growth nutrition unit 2-3 can supply the fertilizer needed for plant growth, and the fertilizer is liquefied state, so the amount of fertilizer usage can be fluidized; the drip irrigation system 2-4 includes a water tank and a water pipe, the water tank is a water storage device, and the water pipe is used for conventional plant drip irrigation; the plant growth nutrient unit 2-3 and the drip irrigation system 2-4 pass through The metering unit is connected; in the process of plant growth, when topdressing is needed, the amount of fertilizer can be controlled, and drip irrigation and topdressing can be realized through the water pipes of the drip irrigation system 2-4, and the metering ratio of the two can also be controlled. The water ratio is used for drip irrigation of plants; the atomization system 2-5 is connected to the water tank to atomize the liquid water in the water tank to adjust the humidity in the greenhouse environment; the heat exchange system 2-6 includes heaters and heat exchangers to heat The heater heats the water in the water tank according to the demand command, and the heated water enters the heat exchanger to transfer the heat to the greenhouse.

For the collection of various data of plants in the growth stage, we start with measuring parameters in the biological field. The number of stomata and epidermal cells per unit area, the size of the stomata: length and width, the number of chloroplasts, the growth height of the plant, and the number of flowering and fruiting can be used as the basis for judging whether the plant growth is good, and then periodically regulate the greenhouse. Environmental control factors that contribute to the state of the environment that is most favorable for plant growth.

The implementation examples of system light control are mainly described below.

The part input by the user includes: the target light intensity I, which is stored in the data storage unit 4; the gain K, whose value is a positive integer; the allowable range E of the light intensity error; and the sampling period T. Compared with the clock frequency CLK of the PLC controller 3, the sampling period should be set large enough to meet the data acquisition. What does not require user input is: the user state M(t) of the occupancy sensor, whether it belongs to a logic high level or a logic low level state; the ambient light sensor, that is, the first photodiode to test the light intensity and size of the outside world entering the greenhouse environment It is A; the sum of the light intensity of the outside world entering the greenhouse environment tested by the second photodiode and the supplementary light intensity of the LED used for plant lighting, the size is L(t); according to the relationship between L(t) and the target light intensity, adjust B=L(t)-A size, that is, the intensity of LED plant lighting supplementary light.

Regarding the control algorithm: it is stipulated that the actual light intensity error e(t)=target light intensity I-measured light intensity L(t). From this, compare the actual light intensity error e(t) with the set light intensity error allowable range E, and judge whether the overall light intensity received by the plants in the greenhouse is within a reasonable range, and use this as a basis to regulate the PWM pulse width. Size, to achieve the purpose of dimming. The specific control algorithm is:

If e(t)≥E, the duty cycle D(t)=M(t)[D(t)+K];

If e(t)≤-E, then the duty cycle D(t)=M(t)[D(t)-K];

Therefore, the user state M(t) of the occupancy sensor has a large impact on the system signal. The response of the system to the algorithm is shown in Figure 5.

Regarding control optimization: the method used is to explore the best results of system optimization by debugging parameters that require user input. It mainly involves the modulation of gain K, light intensity error allowable range E, sampling period T, and three variable parameter settings. Through the control variable method, the conditions for the stability of the system are explored.

For gain K, set K=1, K=2, K=5, K=10 four groups of comparative experiments. As the gain value setting increases, the system reaches a more stable state faster. But at the same time, if the gain value is too large, it is easy to cause an overshoot signal. Especially when the allowable range of light intensity error is set small and the gain is large, the system will reduce the duty cycle to achieve a stable state, which is prone to flicker visible to the human eye.

For the allowable range E of light intensity error, let E=target light intensity I/a, where a is set to four groups of 2, 5, 10, and 20. If the allowable range E of the light intensity error is set too small, flickering is likely to occur in low-frequency conditions; if the allowable range E of the light intensity error is set too large, the error will be large, which will easily lead to inaccuracy of the steady state results of the controller.

For the sampling period T, set T=200μs, T=500μs, T=1ms, T=100ms four comparative experiments. As the sampling period increases, the response time of the system can be shortened accordingly, and the response speed of the system can be improved. With a smaller sampling period, the system is more likely to be disturbed by fluctuations in the environmental state and cause flickering, and the processing load of the controller will also increase.

Based on the above comprehensive analysis, set the gain K=2, the allowable range of light intensity error E=target light intensity I/20, and set the sampling period to T=500μs, which can ensure a relatively stable system performance and accurate output level.

As shown in Figure 6, in order to use PWM pulse width modulation technology, the size of the duty cycle has an impact on the electro-optical conversion efficiency. It can be seen from the figure that the average electro-optical conversion efficiency is close to a constant change, which is about 90.58%.

As shown in Figure 7, it is a comparison chart of power consumption between ordinary LED continuous light supplement lighting and LED plant lighting supplement light control system within a week. The comparison chart shows that by monitoring the ambient light intensity and adjusting the intensity of LED supplementary light in real time to achieve a stable state of light received by plants, energy consumption can be effectively controlled and considerable energy-saving effects can be achieved.

The implementation examples described above are only preferred embodiments of the present utility model, and are not intended to limit the scope of implementation of the present utility model, so all changes made according to the shape and principle of the present utility model should be covered by the scope of the present utility model. within the scope of protection.

Claims (8)

1. A kind of 1. control system for acting on hothouse plants growth, it is characterised in that：Including PLC (3), respectively with PLC The environmentally sensitive system (1) of controller (3) connection, environment conditioning system (2), data storage cell (4) and for man-machine friendship Mutual and system information real-time monitored HMI user interfaces (5).
2. A kind of 2. control system for acting on hothouse plants growth according to claim 1, it is characterised in that：The environment Sensor-based system (1) includes the temperature sensor (1-1), the first of testing soil temperature and humidity warm and humid of test greenhouse ambient temperature Spend the second Temperature Humidity Sensor (1-3) of temperature and humidity, the test external world in sensor (1-2), test greenhouse and enter temperature The first photodiode (1-4) of light intensity, test are extraneous into light intensity in greenhouse and for planting in room environmental Carbon dioxide content is horizontal in the second photodiode (1-5) and test greenhouse of thing illumination LED light filling intensity summation Carbon dioxide sensor (1-6).
3. A kind of 3. control system for acting on hothouse plants growth according to claim 1, it is characterised in that：The environment Regulator control system (2) include LED illumination light filling unit (2-1), ventilation equipment unit (2-2), plant growth nutritional modules (2-3), Drip irrigation system (2-4), atomization system (2-5) and heat-exchange system (2-6).
4. A kind of 4. control system for acting on hothouse plants growth according to claim 3, it is characterised in that：The LED Illumination light filling unit (2-1) includes PWM current driver units (2-1-1) and LED illumination array element (2-1-2), between the two It is attached by photoelectrical coupler；Wherein, the LED illumination array element (2-1-2) includes red-light source module (2-1- 3), blue light source module (2-1-4), green-light source module (2-1-5), it is in parallel between each module.
5. A kind of 5. control system for acting on hothouse plants growth according to claim 4, it is characterised in that：The feux rouges Light source module (2-1-3), blue light source module (2-1-4), green-light source module (2-1-5) wavelength be respectively 650nm~ 670nm, 440nm~460nm, 510nm~530nm.
6. A kind of 6. control system for acting on hothouse plants growth according to claim 4, it is characterised in that：The LED Illumination array unit (2-1-2) is arranged on 1m~2m above plant, and its greatest irradiation illumination is 160W/m², green-light source module (2-1-5) radiant illumination should be it is red, blue light source module (2-1-3,2-1-4) radiant illumination summation 20%；Red, blue phase is to light Spectral structure ratio is 4:1~9:1.
7. A kind of 7. control system for acting on hothouse plants growth according to claim 4, it is characterised in that：The LED Lighting unit LED illumination array element (2-1-2) is driven by PWM, and red, blue, green light source module frequency is disposed as 1kHz- 5kHz, three's phase difference are 0 °, and dutycycle is 20%-50%.
8. A kind of 8. control system for acting on hothouse plants growth according to claim 3, it is characterised in that：The ventilation Unit (2-2) is placed in the top of greenhouse side；Drip irrigation system (2-4) includes water tank and water pipe, and atomization system (2-5) is with being somebody's turn to do Water tank is connected, and the aqueous water in water tank is atomized, and then adjusts the humidity in greenhouse；Heat-exchange system (2-6) is wrapped Heater and heat exchanger are included, heater instructs the water in heating water tank according to demand, and heated water enters heat exchanger, will Heat transfer is to greenhouse.