Greenhouse ventilation control system based on Internet of Things

Abstract

The invention belongs to the technical field of greenhouse control, and discloses a greenhouse ventilation control system based on Internet of Things, which comprises a greenhouse, a main electric roll-up window and an auxiliary electric roll-up window, a central processing module positioned on the main electric roll-up window is used for calculating the opening proportion of the main electric roll-up window and the auxiliary electric roll-up window by adopting an enhanced multivariable PID formula according to the ammonia concentration and the gaseous nitrous acid concentration in the greenhouse and the temperature and the humidity inside and outside the greenhouse; the temperature difference and the humidity difference inside and outside the greenhouse can be accurately mastered through the newly-added heat dissipation condition item and the newly-added humidity elimination condition item, invalid ventilation is effectively reduced, steady-state errors caused by the condensation phenomenon and the wet settlement phenomenon are relieved through the newly-added condensation factor correction item and the newly-added wet settlement factor correction item, the overshoot phenomenon of an enhanced multivariable PID formula is reduced, and the stability of the greenhouse is improved. By means of the technical means, multi-factor accurate, punctual and stable control over the environment in the greenhouse is achieved automatically.

Description

Technical Field

[0001] The present invention belongs to the technical field of greenhouse control, and specifically refers to a greenhouse ventilation control system based on the Internet of Things. Background Art

[0002] At present, most greenhouse ventilation control solutions still use remote controls to control motor ventilation. When the number of greenhouses managed reaches a certain number and the daily ventilation time is too long, the problem of not being able to look after them at the same time exists when using remote controls to control greenhouse ventilation, which seriously prolongs the working hours of greenhouse managers. In addition, there is also the problem of not being able to ventilate on time and accurately. Existing greenhouse ventilation control algorithms also mostly use temperature as a single variable for dual-position control or fuzzy logic control, which cannot ensure the stability of the system, nor can they meet the requirements of crops for environmental factors other than temperature, nor can they accurately grasp the temperature and humidity differences inside and outside the greenhouse, resulting in ineffective ventilation, which seriously affects farmers' production and income increases. Summary of the invention

[0003] In view of the above situation, in order to overcome the defects of the prior art, the present invention provides a greenhouse ventilation control system based on the Internet of Things, which uses a pair of electric rolling shutters located on the front and rear walls of the greenhouse to realize gas exchange inside and outside the greenhouse by using through-drafts, and uses an enhanced multi-variable PID formula to calculate the opening ratio of the electric rolling shutters, thereby realizing automatic multi-factor precise, timely and stable control of the greenhouse environment. The newly added heat dissipation condition items and dehumidification condition items can accurately grasp the temperature difference and humidity difference inside and outside the greenhouse, effectively reducing ineffective ventilation. The present invention saves the working time of greenhouse managers and facilitates single-person management of ventilation of multiple greenhouses.

[0004] The technical solution adopted by the present invention is as follows: A greenhouse ventilation control system based on the Internet of Things provided by the present invention includes a greenhouse, the greenhouse includes a front wall, a rear wall and a greenhouse bracket, the greenhouse ventilation control system based on the Internet of Things also includes a main electric rolling shutter and a slave electric rolling shutter, the main electric rolling shutter is arranged on the front wall, and the slave electric rolling shutter is arranged on the rear wall;

[0005] An inner sensor is fixedly arranged on one side of the main electric rolling shutter window close to the inside of the greenhouse, a central processing module is fixedly arranged on the upper wall of the main electric rolling shutter window, and an outer sensor is fixedly arranged on one side of the main electric rolling shutter window close to the outside of the greenhouse;

[0006] The central processing module is electrically connected to the inner sensor, the outer sensor and the main electric rolling shutter window;

[0007] The internal sensor records the temperature, humidity, ammonia concentration and gaseous nitrite concentration in the greenhouse in real time and inputs them to the central processing module, and the external sensor records the temperature and humidity outside the greenhouse in real time and inputs them to the central processing module;

[0008] The central processing module uses an enhanced multivariable PID formula to control the main electric rolling shutter and the slave electric rolling shutter to ventilate.

[0009] Furthermore, the main electric rolling shutter window shaft is equipped with a first rolling shutter, and the slave electric rolling shutter window shaft is equipped with a second rolling shutter.

[0010] Furthermore, a first antenna is fixed on the upper wall of the central processing module, and a second antenna is fixed on the upper wall of the electric rolling shutter window close to the interior of the greenhouse. The central processing module is electrically connected to the first antenna, the first antenna is communicatively connected to the second antenna, and the electric rolling shutter window is electrically connected to the second antenna.

[0011] Furthermore, the front wall is provided with a door and a first window, the rear wall is provided with a second window, the main electric rolling shutter is provided on the first window, and the slave electric rolling shutter is provided on the second window.

[0012] Furthermore, the process in which the central processing module uses the enhanced multivariable PID formula to control the main electric roller shutter window and the secondary electric roller shutter window to release air specifically includes the following steps:

[0013] Step S1: The greenhouse manager sets the type of crops to be planted in the greenhouse;

[0014] Step S2: The central processing module accesses the Internet through the first antenna, queries the optimum temperature, optimum humidity, LOAEL of ammonia and LOAEL of gaseous nitrous acid corresponding to the crop type, queries whether there is an extreme weather warning in the local area on that day, and generates an extreme weather variable. The default value of the extreme weather variable is 1, and if there is an extreme weather warning in the local area on that day, the value is 0;

[0015] Step S3: The central processing module uses the enhanced multivariable PID formula to calculate the opening ratio of the master electric rolling shutter window and the slave electric rolling shutter window every five seconds;

[0016] Step S4: the central processing module transmits the opening ratio to the master electric rolling window, and transmits it to the slave electric rolling window through the communication connection between the first antenna and the second antenna;

[0017] Step S5: The master electric rolling shutter window and the slave electric rolling shutter window synchronously control the lifting and lowering of the first rolling shutter window and the second rolling shutter window according to the opening ratio.

[0018] Furthermore, the opening ratio in step S3 is the ratio of the opening area of ​​the master electric rolling window 1 and the slave electric rolling window 7 to the total area.

[0019] Furthermore, step S3 specifically includes the following steps:

[0020] Step S31: Calculate the temperature control component of the enhanced multivariable PID formula;

[0021] Step S32: Calculate the humidity control component of the enhanced multivariable PID formula;

[0022] Step S33: Calculate the ammonia concentration control component of the enhanced multivariable PID formula;

[0023] Step S34: calculating the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula;

[0024] Step S35: Calculate the opening ratio of the enhanced multivariable PID formula according to the temperature control component, the humidity control component, the ammonia concentration control component, the gaseous nitrous acid concentration control component and the extreme weather variable.

[0025] Furthermore, in step S31, the calculation formula of the temperature control component is as follows:

[0026] ;

[0027] ;

[0028] in, represents the temperature control component of the enhanced multivariable PID formula, represents the heat dissipation condition term, represents the proportional gain of the temperature control component of the enhanced multivariable PID formula, represents the integral gain of the temperature control component of the enhanced multivariable PID formula, represents the derivative gain of the temperature control component of the enhanced multivariable PID formula, Represents the temperature inside the greenhouse. Represents the temperature outside the greenhouse. represents the optimum temperature, Represents the current time point, Represents the time point ten minutes ago.

[0029] Furthermore, in step S32, the calculation formula of the humidity control component is as follows:

[0030] ;

[0031] ;

[0032] ;

[0033] ;

[0034] in, represents the humidity control component of the enhanced multivariable PID formula, represents the dehumidification condition item, Represents the integral term of the humidity control component after correction by the condensation factor, represents the condensation factor correction term, Represents the humidity in the greenhouse. Represents the humidity outside the greenhouse. Represents the optimum humidity. represents the proportional gain of the humidity control component of the enhanced multivariable PID formula, represents the integral gain of the humidity control component of the enhanced multivariable PID formula, represents the derivative gain of the humidity control component of the enhanced multivariable PID formula, Represents the hyperbolic tangent function.

[0035] Furthermore, in step S33, the calculation formula of the ammonia concentration control component is as follows:

[0036] ;

[0037] ;

[0038] ;

[0039] in, represents the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral term of the humidity control component corrected by the wet deposition factor, represents the wet deposition factor correction term, represents the proportional gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the differential gain of the ammonia concentration control component of the enhanced multivariable PID formula, Represents the ammonia concentration in the greenhouse. Represents the LOAEL of ammonia.

[0040] Further, in step S34, the calculation formula of the gaseous nitrous acid concentration control component is as follows:

[0041] ;

[0042] in, represents the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the proportional gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the integral gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the differential gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, Represents the concentration of gaseous nitrite in the greenhouse. Represents the LOAEL of gaseous nitrous acid.

[0043] Furthermore, in step S35, the calculation formula of the opening ratio is as follows:

[0044]

[0045] in, represents extreme weather variables, Represents the opening ratio.

[0046] Furthermore, the LOAEL refers to the “lowest dose level at which an adverse effect can be observed”.

[0047] The beneficial effects achieved by the present invention using the above scheme are as follows:

[0048] (1) The present invention realizes the automatic control of greenhouse ventilation through the Internet of Things technology. A pair of electric roller shutters located on the front and rear walls of the greenhouse are used to realize gas exchange inside and outside the greenhouse by using the through wind. The enhanced multivariable PID formula is used to calculate the opening ratio according to the ammonia concentration, gaseous nitrite concentration and the temperature and humidity inside and outside the greenhouse, thereby realizing automatic multi-factor accurate, timely and stable control of the greenhouse environment, reducing the damage to crops caused by harmful gases and inappropriate temperature and humidity. The newly added heat dissipation condition item and moisture removal condition item can accurately grasp the temperature difference and humidity difference inside and outside the greenhouse, effectively reducing ineffective ventilation. The present invention saves the labor time of greenhouse managers and facilitates single-person management of ventilation of multiple greenhouses.

[0049] (2) The location of the main electric roller shutter and the secondary electric roller shutter utilizes the through wind to achieve gas exchange inside and outside the greenhouse, and also facilitates the side-by-side installation of multiple greenhouses.

[0050] (3) The present invention can automatically query the optimum temperature, optimum humidity, LOAEL of ammonia and LOAEL of gaseous nitrous acid based on the crop type and adjust the enhanced multivariable PID formula, thereby reducing the cognitive burden of the user. At the same time, the present invention can automatically query whether there is extreme weather and use this to decide whether to open or close the main electric roller shutter and the slave electric roller shutter, thereby achieving automated risk avoidance.

[0051] (4) The present invention uses the control variable method to perform PID tuning on the enhanced multivariable PID formula, ensuring that in practical applications the system can accurately and quickly respond to changes in the climate inside and outside the greenhouse, thereby improving the reliability and stability of the system.

[0052] (5) The enhanced multivariable PID formula combines the various components in the form of maximum value to ensure that no environmental factor exceeds the standard.

[0053] (6) The newly added condensation factor correction term and wet deposition factor correction term alleviate the steady-state error caused by condensation and wet deposition phenomena, reduce the overshoot phenomenon of the enhanced multivariable PID formula, and improve its control accuracy and stability. The hyperbolic tangent function is added to scale the correction term to prevent its size from exceeding the size of the integral term it corrects. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 This is a schematic diagram of the structure of a greenhouse ventilation control system based on the Internet of Things proposed by the present invention. Figure 1 ;

[0055] Figure 2 for Figure 1 A partial enlarged view of part A in FIG.

[0056] Figure 3 This is a schematic diagram of the structure of a greenhouse ventilation control system based on the Internet of Things proposed by the present invention. Figure 2 ;

[0057] Figure 4 for Figure 3 A partial enlarged view of part B in FIG.

[0058] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0059] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0060] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the examples given are only used to explain the present invention, and are not used to limit the scope of the present invention.

[0061] Example 1, see Figure 1 , Figure 2 , Figure 3 and Figure 4 The present invention provides a greenhouse ventilation control system based on the Internet of Things, comprising a greenhouse 10, the greenhouse 10 comprising a front wall 103, a rear wall 102 and a greenhouse support 101, the greenhouse ventilation control system based on the Internet of Things further comprising a main electric rolling shutter 1 and a slave electric rolling shutter 7, the main electric rolling shutter 1 being arranged on the front wall 103, and the slave electric rolling shutter 7 being arranged on the rear wall 102;

[0062] An inner sensor 3 is fixedly arranged on one side of the main electric rolling shutter 1 close to the inside of the greenhouse 10, a central processing module 5 is fixedly arranged on the upper wall of the main electric rolling shutter 1, and an outer sensor 2 is fixedly arranged on one side of the main electric rolling shutter 1 close to the outside of the greenhouse 10;

[0063] The central processing module 5 is electrically connected to the inner sensor 3, the outer sensor 2 and the main electric rolling shutter window 1;

[0064] The internal sensor 3 records the temperature, humidity, ammonia concentration and gaseous nitrite concentration in the greenhouse 10 in real time and inputs them to the central processing module 5, and the external sensor 2 records the temperature and humidity outside the greenhouse 10 in real time and inputs them to the central processing module 5;

[0065] The central processing module 5 uses an enhanced multivariable PID formula to control the main electric rolling shutter 1 and the slave electric rolling shutter 7 to release air.

[0066] Example 2, see Figure 2 and Figure 4 This embodiment is based on the above embodiment, wherein the main electric rolling shutter window 1 is provided with a first rolling shutter 8 on its shaft, and the slave electric rolling shutter window 7 is provided with a second rolling shutter 9 on its shaft.

[0067] Example 3, see Figure 2 and Figure 4 This embodiment is based on the second embodiment, and a first antenna 4 is fixedly provided on the upper wall of the central processing module 5, and a second antenna 6 is fixedly provided on the upper wall of the side of the electric rolling shutter 7 close to the inside of the greenhouse 10, and the central processing module 5 is electrically connected to the first antenna 4, and the first antenna 4 is communicatively connected to the second antenna 6, and the electric rolling shutter 7 is electrically connected to the second antenna 6.

[0068] Example 4, see Figure 1 , Figure 2 , Figure 3 and Figure 4This embodiment is based on the first embodiment, the front wall 103 is penetrated by a door 106 and a first window 105, the rear wall 102 is penetrated by a second window 104, the main electric rolling shutter 1 is arranged on the first window 105, and the slave electric rolling shutter 7 is arranged on the second window 104.

[0069] Embodiment 5, based on Embodiment 3, the central processing module 5 uses the enhanced multivariable PID formula to control the main electric roller shutter 1 and the slave electric roller shutter 7 to release air, and the process specifically includes the following steps:

[0070] Step S1: The greenhouse manager sets the type of crops planted in the greenhouse 10. In this embodiment, tomatoes are planted in the greenhouse 10;

[0071] Step S2: The central processing module 5 accesses the Internet through the first antenna 4, queries the optimum temperature, optimum humidity, LOAEL of ammonia and LOAEL of gaseous nitrite corresponding to the crop type, queries whether there is an extreme weather warning on the local day through the AutoNavi weather API, and generates an extreme weather variable. The default value of the extreme weather variable is 1, and the value is 0 if there is an extreme weather warning on the local day. In this embodiment, the optimum temperature is 25° C., the optimum humidity is 0.5, the LOAEL of ammonia is 5 ppm, the LOAEL of harmless gaseous nitrite is 3 ppm, and the extreme weather variable is 1;

[0072] Step S3: the central processing module 5 uses the enhanced multivariable PID formula to calculate the opening ratio of the master electric rolling shutter window 1 and the slave electric rolling shutter window 7 every five seconds;

[0073] Step S4: the central processing module 5 transmits the opening ratio to the master electric rolling shutter 1, and transmits it to the slave electric rolling shutter 7 through the communication connection between the first antenna 4 and the second antenna 6;

[0074] Step S5: the master electric rolling shutter window 1 and the slave electric rolling shutter window 7 synchronously control the lifting and lowering of the first rolling shutter 8 and the second rolling shutter 9 according to the opening ratio.

[0075] Embodiment 6: This embodiment is based on embodiment 5, and step S3 specifically includes the following steps:

[0076] Step S31: Calculate the temperature control component of the enhanced multivariable PID formula;

[0077] Step S32: Calculate the humidity control component of the enhanced multivariable PID formula;

[0078] Step S33: Calculate the ammonia concentration control component of the enhanced multivariable PID formula;

[0079] Step S34: calculating the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula;

[0080] Step S35: Calculate the opening ratio of the enhanced multivariable PID formula according to the temperature control component, the humidity control component, the ammonia concentration control component, the gaseous nitrous acid concentration control component and the extreme weather variable.

[0081] Embodiment 7: This embodiment is based on embodiment 6. In step S31, the calculation formula of the temperature control component is as follows:

[0082] ;

[0083] ;

[0084] in, represents the temperature control component of the enhanced multivariable PID formula, represents the heat dissipation condition term, represents the proportional gain of the temperature control component of the enhanced multivariable PID formula, represents the integral gain of the temperature control component of the enhanced multivariable PID formula, represents the derivative gain of the temperature control component of the enhanced multivariable PID formula, represents the temperature in the greenhouse 10, represents the temperature outside the greenhouse 10, represents the optimum temperature, Represents the current time point, represents the time point ten minutes ago. In this embodiment, It is 13:10, is 32°C, At 20°C, is 40, is 0.5, is 0.01, is 50, is 0.01, so is 12, and finally It is 0.93.

[0085] Embodiment 8: This embodiment is based on embodiment 7. In step S32, the calculation formula of the humidity control component is as follows:

[0086] ;

[0087] ;

[0088] ;

[0089] ;

[0090] in, represents the humidity control component of the enhanced multivariable PID formula, represents the dehumidification condition item, Represents the integral term of the humidity control component after correction by the condensation factor, represents the condensation factor correction term, represents the humidity in the greenhouse 10, Represents the humidity outside the greenhouse 10, Represents the optimum humidity. represents the proportional gain of the humidity control component of the enhanced multivariable PID formula, represents the integral gain of the humidity control component of the enhanced multivariable PID formula, represents the derivative gain of the humidity control component of the enhanced multivariable PID formula, represents the hyperbolic tangent function. In this embodiment, is 0.55, is 0.7, is 35, is 0.4, is 0.02, is 45, is 0.15, so is 0.54, is 34.5, C2 is 0, and finally is 0.

[0091] Embodiment 9: This embodiment is based on embodiment 8. In step S33, the calculation formula of the ammonia concentration control component is as follows:

[0092] ;

[0093] ;

[0094] ;

[0095] in, represents the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral term of the humidity control component corrected by the wet deposition factor, represents the wet deposition factor correction term, represents the proportional gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the differential gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the ammonia concentration in the greenhouse 10, represents the LOAEL of ammonia. In this embodiment, 3ppm, is 5, is 0.1, is 0.1, is 5, is 0.2, so is 3, is 2, and finally we get is 0.1.

[0096] Embodiment 10: This embodiment is based on embodiment 9. In step S34, the calculation formula of the gaseous nitrous acid concentration control component is as follows:

[0097] ;

[0098] in, represents the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the proportional gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the integral gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the differential gain of the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula, represents the concentration of gaseous nitrite in the greenhouse 10, represents the LOAEL of gaseous nitrous acid. In this embodiment, 2.5ppm, is 5, is 0.1, is 0.1, is 5, is 0.2, so is 0.2.

[0099] Embodiment 11: This embodiment is based on embodiment 10. In step S35, the calculation formula of the opening ratio is as follows:

[0100]

[0101] Where X represents extreme weather variables, Represents the opening ratio. In this embodiment, It is 0.93.

[0102] Embodiment 12: This embodiment is based on embodiment 5, and the opening ratio in step S3 is the ratio of the opening area of ​​the master electric rolling shutter 1 and the slave electric rolling shutter 7 to the total area.

[0103] Embodiment 13, based on Embodiment 11, this embodiment uses an environmental simulation laboratory to perform PID tuning on the enhanced multivariable PID formula, specifically comprising the following steps:

[0104] Step T1: deploying a greenhouse 10 in an environmental simulation laboratory, and deploying a main electric rolling shutter 1 and a slave electric rolling shutter 7 on the greenhouse 10;

[0105] Step T2: Select an environmental factor from temperature, humidity, ammonia concentration and gaseous nitrous acid concentration. The environmental simulation laboratory uses a constant method to control the variables of the remaining environmental factors so that the corresponding component output is 0. In this embodiment, the selected environmental factor is humidity. , and is controlled to 0;

[0106] Step T3: The environmental simulation laboratory uses air conditioning and gas mixers to adjust the selected environmental factors. The greenhouse manager regards the output of the component corresponding to the selected environmental factor in the enhanced multivariable PID formula as the opening ratio, and uses the Ziegler-Nichols method to perform parameter adjustment on the component corresponding to the selected environmental factor in the enhanced multivariable PID formula. In this embodiment, the component corresponding to humidity in the enhanced multivariable PID formula is the humidity control component of the enhanced multivariable PID formula. Considered ;

[0107] Step T4: Repeat steps T2 and T3 until all the components corresponding to the environmental factors in the enhanced multivariable PID formula have been adjusted.

[0108] Embodiment 14. This embodiment is based on the above embodiment. The central processing module 5 queries the AutoNavi weather API to find out that there is a hail warning in the local area on that day. The extreme weather variable is 0 in the following 24 hours. The opening ratio output by the enhanced multivariable PID formula is 0, and the main electric rolling shutter 1 and the slave electric rolling shutter 7 are closed.

[0109] Embodiment 15, this embodiment is based on embodiment 11, this embodiment runs in Windows operating system environment, the implementation of enhanced multivariable PID formula relies on Anaconda3 environment, the main electric roller shutter window 1 and the slave electric roller shutter window 7 are implemented by ZNGZDJ11LM, the first roller shutter 8 and the second roller shutter 9 are made of PVC material, the first antenna 4 and the second antenna 6 are implemented by RF1908021, and the central processing module 5 is implemented by Raspberry Pi The internal sensor 3 is implemented by HONO1000 integrated with WX-B4 and WX-QT4, the external and internal sensor 2 is implemented by WX-B4, the front wall 103 and the rear wall 102 are prefabricated cement board structures, and the greenhouse bracket 101 is made of aluminum alloy. The LOAEL refers to the "lowest dose level at which adverse effects can be observed". The humidity and the optimum humidity are both relative humidity, which expresses the percentage of the water vapor pressure in the air to the saturated water vapor pressure at the same temperature in the form of a percentage decimal. The units of the temperature and the optimum temperature are both degrees Celsius, and the units of the LOAEL of gaseous nitrous acid, the LOAEL of ammonia, the concentration of ammonia and the concentration of gaseous nitrous acid are all ppm.

[0110] The present invention and its embodiments are described above, which is not restrictive. What is shown in the accompanying drawings is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in this field are inspired by it and do not deviate from the purpose of the invention, they can creatively design structural methods and embodiments similar to the technical scheme, which should all fall within the scope of protection of the present invention.

Claims

1. A greenhouse ventilation control system based on the Internet of Things, comprising a greenhouse (10), the greenhouse (10) comprising a front wall (103), a rear wall (102) and a greenhouse support (101), characterized in that: The greenhouse ventilation control system based on the Internet of Things further comprises a main electric rolling shutter (1) and a slave electric rolling shutter (7), wherein the main electric rolling shutter (1) is arranged on the front wall (103) and the slave electric rolling shutter (7) is arranged on the rear wall (102); An inner sensor (3) is fixedly provided on a side of the main electric rolling shutter (1) close to the interior of the greenhouse (10), a central processing module (5) is fixedly provided on the upper wall of the main electric rolling shutter (1), and an outer sensor (2) is fixedly provided on a side of the main electric rolling shutter (1) close to the exterior of the greenhouse (10); The central processing module (5) is electrically connected to the inner sensor (3), the outer sensor (2) and the main electric rolling window (1); The internal sensor (3) records the temperature, humidity, ammonia concentration and gaseous nitrite concentration in the greenhouse (10) in real time and inputs the information to the central processing module (5); the external sensor (2) records the temperature and humidity outside the greenhouse (10) in real time and inputs the information to the central processing module (5); The central processing module (5) uses an enhanced multivariable PID formula to control the main electric rolling shutter (1) and the slave electric rolling shutter (7) to release air.

2. The greenhouse ventilation control system based on the Internet of Things according to claim 1 is characterized in that: The process in which the central processing module (5) uses the enhanced multivariable PID formula to control the main electric rolling shutter (1) and the secondary electric rolling shutter (7) to release air specifically comprises the following steps: Step S1: The greenhouse manager sets the type of crops to be planted in the greenhouse (10); Step S2: The central processing module (5) accesses the Internet to query the optimum temperature, optimum humidity, LOAEL of ammonia and LOAEL of gaseous nitrous acid corresponding to the crop type, and queries whether there is an extreme weather warning in the local area on that day, and generates an extreme weather variable. The default value of the extreme weather variable is 1, and the value is 0 if there is an extreme weather warning in the local area on that day; Step S3: the central processing module (5) uses the enhanced multivariable PID formula to calculate the opening ratio of the master electric rolling window (1) and the slave electric rolling window (7) every five seconds; Step S4: the central processing module (5) transmits the opening ratio to the master electric rolling shutter window (1) and the slave electric rolling shutter window (7); Step S5: the master electric rolling shutter window (1) and the slave electric rolling shutter window (7) operate synchronously according to the opening ratio.

3. The greenhouse ventilation control system based on the Internet of Things according to claim 2 is characterized in that: Step S3 specifically includes the following steps: Step S31: Calculate the temperature control component of the enhanced multivariable PID formula; Step S32: Calculate the humidity control component of the enhanced multivariable PID formula; Step S33: Calculate the ammonia concentration control component of the enhanced multivariable PID formula; Step S34: calculating the gaseous nitrous acid concentration control component of the enhanced multivariable PID formula; Step S35: Calculate the opening ratio of the enhanced multivariable PID formula according to the temperature control component, the humidity control component, the ammonia concentration control component, the gaseous nitrous acid concentration control component and the extreme weather variable.

4. The greenhouse ventilation control system based on the Internet of Things according to claim 3 is characterized in that: In step S31, the calculation formula of the temperature control component is as follows: ； ； in, represents the temperature control component of the enhanced multivariable PID formula, represents the heat dissipation condition term, represents the proportional gain of the temperature control component of the enhanced multivariable PID formula, represents the integral gain of the temperature control component of the enhanced multivariable PID formula, represents the derivative gain of the temperature control component of the enhanced multivariable PID formula, represents the temperature inside the greenhouse (10), represents the temperature outside the greenhouse (10), represents the optimum temperature, Represents the current time point, Represents the time point ten minutes ago.

5. The greenhouse ventilation control system based on the Internet of Things according to claim 3 is characterized in that: In step S33, the calculation formula of the ammonia concentration control component is as follows: ； ； ； in, represents the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral term of the humidity control component corrected by the wet deposition factor, represents the wet deposition factor correction term, represents the proportional gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the integral gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the differential gain of the ammonia concentration control component of the enhanced multivariable PID formula, represents the ammonia concentration in the greenhouse (10), Represents the LOAEL of ammonia.

6. The greenhouse ventilation control system based on the Internet of Things according to claim 1 is characterized in that: The front wall (103) is provided with a door (106) and a first window (105), the rear wall (102) is provided with a second window (104), the main electric rolling window (1) is provided on the first window (105), and the secondary electric rolling window (7) is provided on the second window (104).

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