Intelligent multi-sensor closed-loop associated control fruit ripening control system and control method

Abstract

The application discloses a kind of intelligent multi-sensor closed-loop association control's fruit and vegetable ripening control system and method.The system includes six-way sensor of perception layer, control layer's capacitive screen industrial computer and PLC, and execution layer's refrigerating unit, differential pressure circulating fan and other equipment.Its core innovation is to establish the weighted average of three pulp temperature sensors as main control signal, realize multivariate coupling control through PLC, linkage adjustment refrigeration / heat, ethylene release and gas circulation.At the same time, the system integrates TCP / IP communication protocol, supports touch screen, mobile phone, computer three place association control and instruction interlock.Compared with prior art, the application significantly improves the pulp temperature control precision (up to ±0.3℃), solves the ripening uneven problem caused by traditional single-point temperature measurement lag, and through multiple safety interlocking mechanism, eliminates the risk of misoperation in high ethylene environment, realizes the unattended and precise control of ripening process.

Description

Technical Field

[0001] This invention relates to the field of post-harvest processing and intelligent control technology for agricultural products, specifically to an intelligent multi-sensor closed-loop control system and method for ripening fruits and vegetables. Background Technology

[0002] Fruit and vegetable ripening is a crucial step in regulating market supply and enhancing the commercial value of fruits. Traditional ripening methods are mainly divided into two categories: one is the chemical fumigation method, which relies on natural ambient temperature. This method is greatly limited by season and region, and chemical residues such as ethephon pose food safety risks. The other is the physical method using simple ripening chambers, which involves manually opening and closing valves or manually adjusting instruments to control temperature and ethylene concentration.

[0003] However, existing technologies have significant drawbacks: Extremely low control precision: Traditional systems typically only monitor the air temperature inside the storage room, ignoring the lag in temperature changes of the fruits and vegetables themselves, leading to frequent occurrences of "scorched skin and raw interior" or frost damage. There is a significant thermal resistance delay between air temperature and fruit / vegetable temperature; its transfer function can be simplified as:

[0004] in, It is a time constant, typically lasting several hours. Existing systems lack [a specific mechanism / mechanism]. Effective compensation.

[0005] The sensors are singular and isolated: parameters such as temperature, humidity, and gas concentration operate independently, lacking a unified and coordinated control logic. For example, frequent start-ups and shutdowns of the refrigeration unit can drastically disrupt the ethylene concentration, leading to uneven ripening.

[0006] Insufficient automation: Most existing ripening warehouses require manual on-site supervision, making remote monitoring and fault diagnosis impossible, resulting in low management efficiency.

[0007] The lack of a multi-dimensional safety interlock mechanism means that if ozone is accidentally introduced in a high-concentration ethylene environment, it may cause an explosion risk; or if personnel accidentally enter the warehouse in an oxygen-deficient environment, there is a safety hazard.

[0008] Therefore, there is an urgent need for an intelligent system that can achieve precise control of fruit pulp temperature, coordinated regulation of multiple gas components, and remote control function in three locations. Summary of the Invention

[0009] The present invention aims to solve the above-mentioned technical problems by providing an intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening.

[0010] To solve the above-mentioned technical problems, the present invention provides an intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening, comprising: The sensing layer module includes six heterogeneous sensors installed in the ripening chamber, specifically including: a temperature and humidity sensor, three independently arranged fruit pulp temperature sensors, an ethylene concentration sensor, a carbon dioxide sensor, an oxygen concentration sensor, and an ozone concentration sensor. The control layer module includes a capacitive touch screen industrial control all-in-one machine and a programmable logic controller (PLC). The capacitive touch screen industrial control all-in-one machine is communicatively connected to the sensing layer module and is used to receive sensor data and issue control commands. The PLC is electrically connected to the capacitive touch screen industrial control all-in-one machine. The execution layer module includes a refrigeration unit, a differential pressure circulating fan, a fan unit, an ethylene generator, a humidifier, and an ozone generator. The PLC is electrically connected to the above-mentioned execution layer devices to form a multi-loop closed-loop control. The system is configured to use the fruit temperature data collected by the three fruit temperature sensors as the main control signal, and to control the refrigeration unit to perform refrigeration or heating actions through the PLC. The PLC is configured to execute a three-location joint control protocol to realize synchronous data interaction and control command interlocking between the local touch screen, remote mobile phone and computer.

[0011] Furthermore, the three fruit flesh temperature sensors in the sensing layer module are respectively implanted in the central area, middle area, and near-skin area of ​​the fruits and vegetables to be ripened, to construct a three-dimensional temperature field model inside the fruits and vegetables; the capacitive touch screen industrial control all-in-one computer is configured to calculate the weighted average value of the three fruit flesh temperature sensors, the weighting coefficient of which is preset according to the fruit and vegetable variety, and the value is used as a feedback signal to input to the PID control algorithm to dynamically adjust the compressor frequency and electronic expansion valve opening of the refrigeration unit.

[0012] Furthermore, the control layer module also integrates a three-location joint control communication unit, which supports network communication based on the TCP / IP protocol to realize data synchronization and control command interlocking between the local touch screen of the capacitive touch screen industrial control all-in-one machine, the remote authorized mobile terminal (phone), and the remote monitoring terminal (computer); when any end issues a control command, the interfaces of the other two ends refresh the status in real time, and only the highest priority command source responds at the same time.

[0013] Furthermore, the PLC operates based on multivariable coupled control logic, specifically as follows: When the temperature of the fruit pulp is higher than the upper limit of the set threshold, the refrigeration unit is started and the differential pressure circulation fan is turned on simultaneously to enhance the heat exchange efficiency. When the ethylene concentration is lower than the set value, the ethylene generator is started, and according to the feedback data of the carbon dioxide concentration sensor, the fan unit consists of two parts: an intake fan and an exhaust fan. The fan unit performs a small amount of gas replenishment or exhaust to maintain the gas composition balance in the storage. When the ozone concentration sensor detects that the concentration has reached the preset sterilization threshold and remains there for a set time, the ozone generator is automatically turned off and the fan unit is started for ventilation.

[0014] Furthermore, the temperature and humidity sensor forms a closed-loop control with the humidifier. The system is configured to automatically adjust the atomization amount of the humidifier according to the relative humidity deviation during the heating or cooling stage, so as to prevent condensation caused by temperature difference from damaging the skin of fruits and vegetables.

[0015] Furthermore, the system also includes an alarm and safety interlock mechanism. When the oxygen concentration sensor detects that the oxygen concentration in the storage is lower than the safety lower limit, or the ozone concentration exceeds the human tolerance limit threshold, the PLC forcibly cuts off the power supply to the ethylene generator and the ozone generator, and starts the fan unit and differential pressure circulating fan at full speed for emergency ventilation.

[0016] Furthermore, the following steps are included: S1. Initialization steps: The system performs a power-on self-test and loads a preset ripening process curve through the capacitive touchscreen industrial control all-in-one computer. The process curve includes the set values ​​of pulp temperature, ethylene concentration, and gas composition that change over time. S2. Data acquisition steps: Collect ambient temperature and humidity, fruit pulp temperature, ethylene, carbon dioxide, oxygen and ozone concentration data through six sensors at a preset sampling frequency, and transmit the data to the capacitive touch screen industrial control all-in-one machine; S3. Core control steps: With fruit pulp temperature as the primary control target, a cascade control strategy is adopted. The outer loop is for PID control of fruit pulp temperature, and the output is used as the setpoint for refrigerant flow or heating amount in the inner loop. At the same time, ethylene concentration and gas composition are introduced into the control system as feedforward compensation signals. S4. Actuator linkage step: Based on the calculation results of step S3, the PLC outputs PWM or analog signals to drive the refrigeration unit, differential pressure circulating fan, ethylene generator, humidifier, ozone generator and fan unit to perform coordinated actions. S5. Remote Interaction Steps: Through the three-location joint control system, the data collected in step S2 is uploaded to the cloud server and visualized and remotely intervened on the mobile APP and computer host computer software.

[0017] Furthermore, the processing method for the three fruit pulp temperature data in step S3 is as follows: Kalman filtering is applied to the data collected by the three fruit pulp temperature sensors to eliminate noise interference, and then the average value is calculated. ,when When, start full-power cooling / heating; when When, activate the variable frequency speed control mode; when At that time, maintain the current state, where .

[0018] Furthermore, the actuator linkage described in step S4 has timing constraints: the start-up of the ethylene generator must lag behind the start-up of the differential pressure circulating fan by at least 30 seconds, and the start-up and shutdown of the ozone generator are mutually exclusive with the ethylene generator, and the two must not operate in the same time period to avoid the decomposition and destruction of ethylene molecules by strong oxidants.

[0019] Furthermore, the method also includes a self-learning optimization step: the system records the actual ripening time and quality data of different batches of fruits and vegetables under the same process curve, and continuously corrects the parameter weights in the process curve through machine learning algorithms to achieve adaptive ripening control for fruits and vegetables of different origins and varieties.

[0020] The advantages of this invention compared to the prior art are: High temperature control accuracy: Through multi-point monitoring by three fruit flesh temperature sensors, the random errors of single-point temperature measurement are eliminated, resulting in high precision in fruit flesh temperature control. This effectively avoids uneven heating and cooling.

[0021] Good ripening uniformity: The linkage control of differential pressure circulating fan with refrigeration / heating and ethylene release ensures uniform distribution of gas and temperature in the storage, and the color difference of fruit is significantly reduced after ripening.

[0022] High level of intelligence: The fusion of data from six sensors enables fully automatic unattended operation. Combined with the three-location joint control function, managers can intervene anytime and anywhere, improving management efficiency by more than 80%.

[0023] High safety and reliability: The built-in oxygen and ozone interlocking mechanism fundamentally eliminates chemical and physical safety risks, ensuring the safety of personnel and equipment.

[0024] Wide range of applications: This equipment is highly adaptable and can be flexibly applied to both fixed and mobile ripening warehouses. It is also compatible with two common power supply voltages, 380V and 220V, and can adapt to ripening operation needs in different locations and with different power supply conditions. It has a wide range of applications and strong practicality, forming a complete technical advantage system of high precision, high uniformity, intelligence, high safety, and multi-scenario adaptability, with excellent comprehensive application effect. Attached Figure Description

[0025] Figure 1 This is a flowchart of the system architecture of the present invention; Figure 2 This is the main flowchart of the control method of the present invention; Figure 3 This is a flowchart of the fruit pulp temperature control process of the present invention; Figure 4 This is a flowchart of the safety interlocking mechanism of the present invention; Figure 5 This is a flowchart illustrating the actuator linkage timing constraint of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] This invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of this invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not adhering to the usual scale. Furthermore, the schematic diagrams are merely examples and should not be construed as limiting the scope of protection of this invention. In actual fabrication, the three-dimensional spatial dimensions of length, width, and depth should be included.

[0030] Furthermore, in the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used solely for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first," "second," or "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0031] Unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" in this invention should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; similarly, they can refer to mechanical connections, electrical connections, or direct connections, or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Example 1: Batch ripening control of bananas (standard process)

[0033] This embodiment is applied to the ripening workshop of a large banana importer, with a processing capacity of 1,000 boxes (approximately 20 tons).

[0034] Parameter settings: The "Banana Standard Ripening Curve" is accessed via the capacitive touchscreen industrial control all-in-one computer. The target pulp temperature is set to... The relative humidity is 90%-95%, and the ethylene concentration is 100ppm.

[0035] System operation: Initially, the three fruit pulp temperature sensors showed an average temperature of The PLC immediately starts the refrigeration unit and activates the differential pressure circulation fan at full speed.

[0036] When the fruit flesh temperature drops At this time, the PLC switches to PID control mode to control the compressor to run at a reduced frequency.

[0037] The temperature of the fruit pulp stabilizes at After a 30-second delay, the system starts the ethylene generator and releases ethylene through ultrasonic atomization.

[0038] When the carbon dioxide concentration rises to 3%, the fan unit starts intermittently to replace the air with fresh air.

[0039] Data recording: The entire process lasted 72 hours. During this time, management personnel viewed real-time data via a mobile app but did not intervene.

[0040] Results: After ripening, 30 bananas were randomly selected for color difference analysis. The standard deviation of the L value (brightness) was only 1.2, indicating that the ripeness was highly consistent.

[0041] Example 2: Abnormal handling during mango ripening process (safety interlock)

[0042] This embodiment demonstrates the system's response mechanism under abnormal operating conditions.

[0043] Operating conditions: The ripening chamber is currently ripening mangoes; set the fruit flesh temperature. .

[0044] Abnormal trigger: In the 36th hour, the aging of the door seal caused a slight leak, and the oxygen concentration sensor detected that the oxygen concentration inside the warehouse dropped sharply from 21% to 16%.

[0045] System response: The PLC logic determines that the oxygen concentration is below the safe threshold (set to 18%).

[0046] The system immediately executes the first-level interlock: forcibly shutting down the ethylene generator and ozone generator (at this time, the ozone generator is not turned on), cutting off the gas supply.

[0047] Simultaneously, the secondary interlock is activated: the fan unit and differential pressure circulating fan are started at full speed to perform forced ventilation.

[0048] The capacitive touchscreen industrial control all-in-one computer popped up a red alarm and simultaneously sent a text message alarm to the administrator's mobile phone via the 4G network: "The oxygen concentration in ripening warehouse A-02 is low, and emergency ventilation has been activated."

[0049] Recovery: After 5 minutes, the oxygen concentration rose back to 20.5%, the system automatically deactivated the alarm, and resumed the original ripening process after confirming safety.

[0050] Results: Successfully avoided the risk of anaerobic respiration of the fruit (producing an alcoholic smell) and potential suffocation of personnel caused by lack of oxygen.

[0051] Example 3: Precise temperature control and ozone sterilization during the post-ripening period of kiwifruit (three-site joint control)

[0052] This embodiment demonstrates the precision of control and remote management for kiwifruit, a temperature-sensitive berry.

[0053] Initial state: Kiwifruit are stored at a relatively low temperature (approximately...) ).

[0054] Three-location operation: At 9:00 AM, the operator started the "kiwi ripening" program in the workshop using a capacitive touchscreen industrial control computer, setting the target fruit flesh temperature. .

[0055] At 12:00 noon, the manager checked the progress via a mobile app while on a business trip and found that the temperature was rising too slowly. He then remotely adjusted the PID parameters and increased the heating compensation coefficient.

[0056] At 3:00 PM, the quality control officer retrieved historical data from the computer in the office to check for temperature fluctuations and issued an order to start the ozone generator for disinfection inside the storage room (at which point the fruit had already been removed).

[0057] Control details: The system strictly adheres to "fruit pulp temperature control," even though the ambient temperature has reached... However, because the three fruit pulp temperature sensors showed that the center temperature was still... The system determined that the standard was not met and continued heating and circulation.

[0058] Effect: The final fruit firmness improved from when it was stored. Evenly descend to And it did not become soft, rotten or moldy.

[0059] Table 1: Comparison of key process parameters and performance indicators of the three embodiments.

[0060]

[0061] Table 2: Performance data comparison between the system of the present invention and existing technology systems

[0062] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A fruit and vegetable ripening control system and method with intelligent multi-sensor closed-loop joint control, characterized in that, include: The sensing layer module includes six heterogeneous sensors installed in the ripening chamber, specifically including: a temperature and humidity sensor, three independently arranged fruit pulp temperature sensors, an ethylene concentration sensor, a carbon dioxide sensor, an oxygen concentration sensor, and an ozone concentration sensor. The control layer module includes a capacitive touch screen industrial control all-in-one machine and a programmable logic controller (PLC). The capacitive touch screen industrial control all-in-one machine is communicatively connected to the sensing layer module and is used to receive sensor data and issue control commands. The PLC is electrically connected to the capacitive touch screen industrial control all-in-one machine. The execution layer module includes a refrigeration unit, a differential pressure circulating fan, a fan unit, an ethylene generator, a humidifier, and an ozone generator. The PLC is electrically connected to the above-mentioned execution layer devices to form a multi-loop closed-loop control. The system is configured to use the fruit temperature data collected by the three fruit temperature sensors as the main control signal, and to control the refrigeration unit to perform refrigeration or heating actions through the PLC. The PLC is configured to execute a three-location joint control protocol to realize synchronous data interaction and control command interlocking between the local touch screen, remote mobile phone and computer.

2. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 1, characterized in that: The three fruit flesh temperature sensors in the sensing layer module are respectively implanted in the central area, middle area and near-skin area of ​​the fruit and vegetables to be ripened, to construct a three-dimensional temperature field model inside the fruit and vegetables; the capacitive touch screen industrial control integrated computer is configured to calculate the weighted average value of the three fruit flesh temperature sensors, the weighting coefficient of which is preset according to the fruit and vegetable variety, and input the value as a feedback signal to the PID control algorithm to dynamically adjust the compressor frequency and electronic expansion valve opening of the refrigeration unit.

3. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 1, characterized in that... The control layer module also integrates a three-location joint control communication unit, which supports network communication based on the TCP / IP protocol to realize data synchronization and control command interlocking between the local touch screen of the capacitive touch screen industrial control all-in-one machine, the remote authorized mobile terminal (phone), and the remote monitoring terminal (computer); when any end issues a control command, the interfaces of the other two ends refresh the status in real time, and only the highest priority command source responds at the same time.

4. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 1, characterized in that: The PLC operates based on multivariable coupled control logic, specifically: When the temperature of the fruit pulp is higher than the upper limit of the set threshold, the refrigeration unit is started and the differential pressure circulation fan is turned on simultaneously to enhance the heat exchange efficiency. When the ethylene concentration is lower than the set value, the ethylene generator is started, and according to the feedback data of the carbon dioxide concentration sensor, the fan unit consists of two parts: an intake fan and an exhaust fan. The fan unit performs a small amount of gas replenishment or exhaust to maintain the gas composition balance in the storage. When the ozone concentration sensor detects that the concentration has reached the preset sterilization threshold and remains there for a set time, the ozone generator is automatically turned off and the fan unit is started for ventilation.

5. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 1, characterized in that: The temperature and humidity sensor forms a closed-loop control with the humidifier. The system is configured to automatically adjust the atomization amount of the humidifier according to the relative humidity deviation during the heating or cooling stage to prevent condensation caused by temperature difference from damaging the skin of fruits and vegetables.

6. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 1, characterized in that: The system also includes an alarm and safety interlock mechanism. When the oxygen concentration sensor detects that the oxygen concentration in the storage is lower than the safety lower limit, or the ozone concentration exceeds the human tolerance limit threshold, the PLC forcibly cuts off the power supply to the ethylene generator and the ozone generator, and starts the fan unit and differential pressure circulating fan at full speed for emergency ventilation.

7. A smart multi-sensor closed-loop control system and method for fruit and vegetable ripening according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1. Initialization steps: The system performs a power-on self-test and loads a preset ripening process curve through the capacitive touchscreen industrial control all-in-one computer. The process curve includes the set values ​​of pulp temperature, ethylene concentration, and gas composition that change over time. S2. Data acquisition steps: Collect ambient temperature and humidity, fruit pulp temperature, ethylene, carbon dioxide, oxygen and ozone concentration data through six sensors at a preset sampling frequency, and transmit the data to the capacitive touch screen industrial control all-in-one machine; S3. Core control steps: With fruit pulp temperature as the primary control target, a cascade control strategy is adopted. The outer loop is for PID control of fruit pulp temperature, and the output is used as the setpoint for refrigerant flow or heating amount in the inner loop. At the same time, ethylene concentration and gas composition are introduced into the control system as feedforward compensation signals. S4. Actuator linkage step: Based on the calculation results of step S3, the PLC outputs PWM or analog signals to drive the refrigeration unit, differential pressure circulating fan, ethylene generator, humidifier, ozone generator and fan unit to perform coordinated actions. S5. Remote Interaction Steps: Through the three-location joint control system, the data collected in step S2 is uploaded to the cloud server and visualized and remotely intervened on the mobile APP and computer host computer software.

8. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 7, characterized in that: The processing method for the three fruit pulp temperature data points mentioned in step S3 is as follows: Kalman filtering is applied to the data collected by the three fruit pulp temperature sensors to eliminate noise interference, and then the average value is calculated. ,when When, start full-power cooling / heating; when When, activate the variable frequency speed control mode; when At that time, maintain the current state, where .

9. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 7, characterized in that: The actuator linkage described in step S4 has timing constraints: the start-up of the ethylene generator must lag behind the start-up of the differential pressure circulating fan by at least 30 seconds, and the start-up and shutdown of the ozone generator are mutually exclusive with the ethylene generator. The two must not operate in the same time period to avoid the decomposition and destruction of ethylene molecules by strong oxidants.

10. The intelligent multi-sensor closed-loop control system and method for fruit and vegetable ripening according to claim 7, characterized in that: The method also includes a self-learning optimization step: the system records the actual ripening time and quality data of different batches of fruits and vegetables under the same process curve, and continuously corrects the parameter weights in the process curve through machine learning algorithms to achieve adaptive ripening control for fruits and vegetables of different origins and varieties.

Images