A cold storage regulating system and method based on gradient temperature control

Abstract

This invention relates to the field of cold storage collaborative control technology, and discloses a cold storage control system and method based on gradient temperature control. The system includes a data acquisition module, a state extraction module, a decision-making and early warning module, and an execution control module. The data acquisition module collects cold storage environmental parameters and fruit physiological parameters. The state extraction module performs feature extraction and state quantification to obtain a cold storage state vector composed of chilling injury cumulative integral, respiration quotient, deastringency electrical index, near-infrared verification results, ethylene change rate, and acceleration. The decision-making and early warning module performs collaborative decision-making and early warning, generating a control instruction set including stage switching instructions, chilling injury intervention instructions, and ethylene intervention instructions. The execution control module executes the control instruction set. This invention realizes dynamic intervention of chilling injury risk during cold storage, real-time feedback of deastringency progress, and graded interception of ethylene autocatalytic bursts, improving the deastringency completion rate, the stability of out-of-storage quality, and the ability to coordinate control multiple parameters.

Description

Technical Field

[0001] This invention relates to the field of cold storage collaborative control technology, specifically to a cold storage control system and method based on gradient temperature control. Background Technology

[0002] Fruits with climacteric respiration exhibit vigorous postharvest physiological metabolism and require a complete de-astringency process to meet edible quality standards. Their de-astringency process is highly coupled with the fruit's post-ripening and senescence process, resulting in significant dynamic changes in their physiological state and extreme sensitivity to storage environment parameters. Consequently, the postharvest preservation and cold storage control of this type of fruit are far more challenging than those of conventional fruits and vegetables.

[0003] During cold storage, fluctuations in storage environment parameters such as temperature, gas composition, and ethylene concentration can easily lead to irreversible quality deterioration. Low-temperature stress can cause chilling injury to fruit, inducing quality defects such as browning of the flesh, hardening of tissues, and reduced juice yield. At the same time, improper environmental control can also lead to incomplete astringency removal, residual astringency, or continued ripening after astringency removal, resulting in excessive softening, rotting, and spoilage. This significantly reduces the marketable fruit rate, causes serious post-harvest losses, and greatly restricts the off-peak storage, long-distance cold chain distribution, and year-round market supply of fruit.

[0004] Currently, gradient temperature control coupled with controlled atmosphere storage is the mainstream technology in the field of fruit and vegetable preservation to improve storage quality and extend storage period. By constructing a multi-stage temperature gradient and matching the corresponding controlled atmosphere parameter range, it can avoid acute chilling injury to a certain extent and steadily promote the fruit de-astringency process, effectively improving the shortcomings of traditional constant temperature storage mode in which it is difficult to balance preservation and ripening inhibition with de-astringency and quality improvement.

[0005] However, the gradient controlled atmosphere technology currently used in cold storage for such fruits is still relatively rudimentary. It employs a fixed-duration, segmented, open-loop control logic, which fails to adapt to the complex and variable post-harvest physiological characteristics of fruits. Existing technologies generally switch temperature and gas parameters at each stage based on a preset storage duration, without considering the individual fluctuations in physiological processes caused by differences in maturity, cultivation conditions, and field microenvironment among different harvest batches of fruit. This results in significant differences in the peak respiration rate and the astringency removal cycle between different batches. Uniform, fixed staged control parameters easily lead to insufficient astringency removal in some fruits, leaving residual astringency, or failure to promptly switch to a stable storage mode after astringency removal, resulting in excessive ripening and softening of the fruit. Overall, storage adaptability and quality stability are poor.

[0006] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this application and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a cold storage control system and method based on gradient temperature control, which to some extent solves the problems raised in the background technology, realizes dynamic intervention of cold damage risk during cold storage, real-time feedback of deacidification progress and graded interception of ethylene autocatalytic burst, and improves the deacidification completion rate, the stability of outgoing quality and the ability of multi-parameter coordinated control.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a cold storage control system based on gradient temperature control, including a data acquisition module, a status extraction module, a decision warning module and an execution control module;

[0010] The data acquisition module is used to collect cold storage environmental parameters and fruit physiological parameters, and to preprocess the cold storage environmental parameters and fruit physiological parameters;

[0011] The state extraction module performs feature extraction and state quantification on the cold storage environmental parameters and fruit physiological parameters to obtain a cold storage state vector; the cold storage state vector consists of the cumulative integral of chilling injury, respiration quotient, deacidification electrical index, near-infrared verification results, ethylene change rate and acceleration.

[0012] The decision-making and early warning module makes collaborative decisions and issues early warnings based on the cold storage state vector and preset priority conditions, generating a control instruction set that includes stage switching instructions, cold damage intervention instructions, and ethylene intervention instructions.

[0013] The execution control module is used to drive the actuator to execute the control instructions in the control instruction set.

[0014] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the state extraction module is configured with a cold damage cumulative integral calculation strategy, specifically including:

[0015] After storing the same batch of fruit for the same period of time in different constant temperature ranges, the decrease in pulp browning rate and juice yield was detected. The decrease in pulp browning rate and juice yield was normalized and then summed to obtain the chilling injury effect of the corresponding temperature range.

[0016] Using the chilling injury effect of the temperature range with the most severe chilling injury as the benchmark value, the ratio of the chilling injury effect of each temperature range to the benchmark value is calculated to obtain the chilling injury weighting coefficient of the corresponding temperature range.

[0017] The cumulative integral of the cold damage is obtained by weighting and integrating the time series of the cold storage temperature based on the aforementioned cold damage weighting coefficient.

[0018] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the state extraction module is further configured with a de-clamping electrical index calculation strategy, specifically including:

[0019] The impedance modulus and capacitance values ​​of the fruit when it is completely de-astringent were obtained through experimental calibration, and were used as the final values ​​of impedance modulus and capacitance. The impedance modulus and capacitance values ​​measured when the fruit was put into storage were used as the reference values.

[0020] Calculate the difference between the reference value of the impedance magnitude and the current impedance magnitude to obtain the first difference of the impedance magnitude, and calculate the difference between the reference value of the impedance magnitude and the final value of the impedance magnitude to obtain the second difference of the impedance magnitude.

[0021] Calculate the ratio of the first difference in impedance magnitude to the second difference in impedance magnitude to obtain the first ratio;

[0022] Calculate the difference between the reference value and the current capacitance value to obtain the first difference in capacitance value, and calculate the difference between the reference value and the final value of capacitance value to obtain the second difference in capacitance value;

[0023] Calculate the ratio of the first difference in capacitance value to the second difference in capacitance value to obtain the second ratio; perform a weighted summation of the first ratio and the second ratio to obtain the decoupling electrical index.

[0024] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the state extraction module is further configured with a near-infrared verification result acquisition strategy for verifying the de-abrasion completion rate, specifically including:

[0025] The original absorbance array was processed by first-order derivative, and a partial least squares model was established.

[0026] The original absorbance array after processing the first derivative is input into the partial least squares model to obtain the predicted value of soluble tannin content.

[0027] If the predicted soluble tannin content is less than or equal to the preset content threshold, the near-infrared verification result indicates that deacidification is complete; otherwise, the near-infrared verification result indicates that deacidification is incomplete.

[0028] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the decision-making and early warning module is configured with a collaborative decision-making and early warning strategy, specifically including:

[0029] If the cold storage state vector satisfies any priority condition, then the corresponding control command is generated;

[0030] Otherwise, a corresponding stage switching instruction is generated based on the interval of the respiratory quotient value, and a corresponding ethylene intervention instruction is generated based on the ethylene change rate and acceleration.

[0031] The preset priority conditions, from high to low, are: forced outbound condition, ethylene level 3 early warning condition, cold damage intervention condition, and deacidification completion switching condition;

[0032] The ethylene intervention command is executed together with the phase switching command during the same period.

[0033] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the method for determining the forced exit condition is as follows: if the cumulative cold damage integral is greater than or equal to a preset cold damage danger threshold, then the forced exit condition is determined to be met, and a forced exit cold damage intervention command is generated.

[0034] The determination method for the ethylene level 3 warning condition is as follows: if the ethylene change rate is greater than or equal to the preset ethylene level 3 warning change rate threshold, or the ethylene concentration is greater than or equal to the preset ethylene level 3 warning concentration threshold, then the ethylene level 3 warning condition is determined to be met, and an ethylene emergency intervention command is generated.

[0035] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the method for determining the cold damage intervention condition is as follows: if the cumulative cold damage integral is greater than or equal to the preset cold damage intervention threshold, and the ethylene level 3 early warning condition is not met, then the cold damage intervention condition is determined to be met, and a cold damage intervention command for temperature recovery is generated.

[0036] The method for determining the desiccation completion switching condition is as follows: if the respiratory quotient value is less than the preset desiccation completion respiratory quotient threshold, and the duration is greater than or equal to the preset stable duration threshold, and the desiccation electrical index is greater than or equal to the preset desiccation completion electrical threshold, and the near-infrared verification result is desiccation completion, then it is determined that the desiccation completion switching condition is met, and a stage switching instruction to switch to the stable storage stage is generated.

[0037] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the method for generating corresponding stage switching instructions based on the respiratory quotient value interval is as follows:

[0038] When the respiratory quotient value is less than the preset deastringency initiation threshold, the fruit is determined to be in the deastringency initiation period, and a stage switching instruction to switch to the deastringency initiation period is generated.

[0039] When the respiratory quotient is greater than or equal to the de-astringency initiation threshold and less than the preset de-astringency acceleration threshold, the fruit is determined to be in the de-astringency acceleration period, and a stage switching instruction to switch to the de-astringency acceleration period is generated.

[0040] When the respiratory quotient is greater than or equal to the de-astringency acceleration threshold and less than the preset de-astringency peak threshold, the fruit is determined to be in the de-astringency peak period, and a stage switching instruction to switch to the de-astringency peak period is generated.

[0041] The stage switching command includes the temperature setting value and tolerance, oxygen concentration setting value, carbon dioxide concentration range and humidity range corresponding to the deacidification stage.

[0042] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the specific method for generating corresponding ethylene intervention commands based on the ethylene change rate and acceleration is as follows:

[0043] When the ethylene change rate is greater than or equal to the preset ethylene level 1 warning change rate threshold and less than the ethylene level 3 warning change rate threshold, the ethylene level 1 warning condition is met, and an ethylene level 1 intervention command is generated.

[0044] When the ethylene change rate is greater than or equal to the preset ethylene level 2 warning change rate threshold, or the ethylene acceleration is greater than or equal to the preset ethylene acceleration warning threshold, the ethylene level 2 warning condition is determined to be met, and an ethylene level 2 intervention command is generated.

[0045] If both the Level II and Level I warning conditions for ethylene are met simultaneously, then the Level II warning condition shall apply.

[0046] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the execution control module is configured with a control command execution strategy to drive the actuator to execute control commands in a control command set; the control command execution strategy specifically includes:

[0047] The actuators include a refrigeration unit, a humidifier, a dehumidifier, a controlled atmosphere valve, a ventilation fan, an ozone generator, a 1-methylcyclopropene slow-release device, and a temperature recovery heater; each actuator is electrically connected to the execution control module.

[0048] If the control command is a forced release from the cold storage to intervene in cold damage, an audible and visual alarm will be issued, all control command execution will be stopped, and a release notification will be sent to the cold storage management system.

[0049] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the control command execution strategy further includes:

[0050] If the control command is an ethylene emergency intervention command, then the 1-methylcyclopropene slow-release device is activated to release 1-methylcyclopropene at a preset dose, and a cooling command is sent to the refrigeration unit. At the same time, the ventilation fan is activated to perform forced ventilation for a preset ventilation duration.

[0051] If the control command is a cold damage intervention command for temperature recovery, then the temperature recovery heater is activated to raise the temperature of the cold storage to the preset temperature recovery target temperature, and after maintaining the temperature rise for a preset duration, the refrigeration unit is controlled to return to the target temperature set value of the current stage at a preset rate of temperature reduction.

[0052] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the control command execution strategy further includes:

[0053] If the control command is a stage switching command, the opening of the refrigerant valve of the refrigeration unit is adjusted by the PID controller to keep the temperature of the cold storage within the tolerance range of the temperature set value.

[0054] By adjusting the gas control valve, the oxygen concentration is made to reach the set oxygen concentration value, and the carbon dioxide concentration is kept within the carbon dioxide concentration range.

[0055] By adjusting the humidifier or dehumidifier, the humidity of the cold storage can be brought to the set humidity value.

[0056] As a preferred embodiment of the gradient temperature control-based cold storage control system described in this application, the control command execution strategy further includes:

[0057] If the control command is an ethylene level 1 intervention command, the ventilation fan's air exchange frequency will be increased to a preset level 1 air exchange frequency, and the ozone generator will be started to release a preset level 1 ozone concentration for a preset level 1 ozone treatment duration.

[0058] If the control command is an ethylene secondary intervention command, the oxygen concentration will be reduced by a preset secondary oxygen reduction rate through the atmosphere control valve, and the carbon dioxide concentration will be increased by a preset secondary carbon dioxide increase rate. At the same time, the ventilation frequency of the ventilation fan will be increased to a preset secondary ventilation frequency.

[0059] Secondly, the present invention provides a cold storage control method based on gradient temperature control, comprising the following steps:

[0060] Collect cold storage environmental parameters and fruit physiological parameters, and preprocess the cold storage environmental parameters and fruit physiological parameters;

[0061] Feature extraction and state quantization are performed on the cold storage environmental parameters and fruit physiological parameters to obtain the cold storage state vector;

[0062] The cold storage state vector consists of the cumulative integral of cold damage, the respiration quotient, the de-astringency electrical index, the near-infrared verification results, the ethylene change rate and acceleration.

[0063] Based on the cold storage state vector and preset priority conditions, collaborative decision-making and early warning are performed to generate a control instruction set that includes stage switching instructions, cold damage intervention instructions and ethylene intervention instructions, and drive the actuator to execute the control instructions in the control instruction set.

[0064] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0065] By collecting and preprocessing cold storage environmental parameters and fruit physiological parameters, a reliable data source is provided for cold damage intervention, astringency removal progress feedback, and ethylene graded interception. Feature extraction and state quantification of these parameters yield a cold storage state vector composed of cold damage cumulative integral, respiration quotient, astringency removal electrical index, near-infrared verification results, ethylene change rate, and acceleration. This vector comprehensively covers the dynamic characteristics of cold damage, astringency removal, and ethylene, ensuring the completeness of input for multi-parameter collaborative control. Based on this cold storage state vector and preset priority conditions, collaborative decision-making and early warning are performed, generating a control instruction set containing stage switching instructions, cold damage intervention instructions, and ethylene intervention instructions. This drives the actuators to execute the control instructions in the control instruction set, achieving dynamic intervention of cold damage risk, real-time closed-loop feedback of astringency removal progress, and graded interception of ethylene autocatalytic bursts. This improves the astringency removal completion rate, the stability of outgoing quality, and the multi-parameter collaborative control capability. Attached Figure Description

[0066] Figure 1 A framework diagram of a cold storage control system based on gradient temperature control provided for this application;

[0067] Figure 2 The flowchart for collaborative decision-making and early warning provided in this application;

[0068] Figure 3 A flowchart of a cold storage control method based on gradient temperature control provided in this application. Detailed Implementation

[0069] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof.

[0070] Example 1

[0071] like Figure 1 As shown, this embodiment introduces a cold storage control system based on gradient temperature control, including a data acquisition module, a status extraction module, a decision-making and early warning module, and an execution control module; this embodiment takes the cold storage control of persimmon, a typical climacteric fruit, as an example for detailed explanation;

[0072] The data acquisition module is used to collect cold storage environmental parameters and fruit physiological parameters, and to preprocess the cold storage environmental parameters and fruit physiological parameters; the cold storage environmental parameters include wind speed, temperature, humidity, oxygen concentration, carbon dioxide concentration and ethylene concentration of the persimmon cold storage; the fruit physiological parameters include respiratory quotient, electrical parameters and near-infrared spectrum.

[0073] The environmental parameters of the cold storage are collected as follows: a hot-film anemometer is installed between the air inlet and the shelf layer of the persimmon cold storage, and the air speed of the persimmon cold storage is collected through the hot-film anemometer; PT100 platinum resistance temperature sensors are installed in the center of the shelf, the return air inlet, and the corner of the persimmon cold storage, and the temperature of the persimmon cold storage is collected through the PT100 platinum resistance temperature sensors; a capacitive humidity sensor is installed at the same location as the PT100 platinum resistance temperature sensor, and the humidity of the persimmon cold storage is collected through the capacitive humidity sensor; an electrochemical oxygen sensor and a non-dispersive infrared carbon dioxide sensor are installed in the return air duct and the middle of the shelf of the persimmon cold storage, and the oxygen concentration and carbon dioxide concentration of the persimmon cold storage are collected through the electrochemical oxygen sensor and the non-dispersive infrared carbon dioxide sensor, respectively; a photoionization ethylene sensor is installed in the return air inlet and the center of the shelf of the persimmon cold storage, and the ethylene concentration of the persimmon cold storage is collected through the photoionization ethylene sensor.

[0074] In this embodiment, the temperature and humidity of the persimmon cold storage are collected every minute, the oxygen concentration, carbon dioxide concentration and ethylene concentration are collected every ten minutes, and the wind speed of the persimmon cold storage is collected every half hour.

[0075] The physiological parameters of the fruit were collected as follows: a miniature sealed breathing chamber was configured for every 1000 kg of persimmons in the persimmon cold storage space; an electrochemical oxygen sensor and a non-dispersive infrared carbon dioxide sensor were installed in the miniature sealed breathing chamber to collect and calculate the oxygen consumption rate and carbon dioxide production rate required for the respiratory quotient; interdigitated electrode arrays were embedded on the surface of the persimmon cold storage shelves, with each electrode array corresponding to approximately 50 persimmons, and the impedance modulus and capacitance values ​​of the persimmons were collected through the interdigitated electrode arrays as electrical parameters; a portable near-infrared spectrometer was deployed in the persimmon cold storage space, and the portable near-infrared spectrometer was aimed at the persimmons corresponding to the interdigitated electrode arrays for non-contact scanning to collect the raw absorbance array of the near-infrared spectrum of the persimmons; the detection wavelength range of the portable near-infrared spectrometer was 900 to 1700 nm.

[0076] In this embodiment, the electrical parameters are measured once a day; the absorbance array of the infrared spectrum is collected once a week; the miniature sealed breathing chamber is automatically closed for 15 minutes every 2 hours, and the oxygen consumption rate and carbon dioxide production rate are obtained by measuring the rate of change of oxygen concentration and the rate of change of carbon dioxide concentration during the closure period.

[0077] The specific method for preprocessing the cold storage environmental parameters and fruit physiological parameters is as follows: The raw data collected by each sensor is filtered for noise reduction and unit conversion is performed; specifically, the raw wind speed signal collected by the hot-film anemometer is subjected to a first-order low-pass filter to eliminate high-frequency noise caused by airflow turbulence; the arithmetic mean of all wind speeds after the first-order low-pass filter is calculated to obtain the wind speed in the persimmon cold storage at the corresponding sampling time; the raw resistance value collected by each PT100 platinum resistance temperature sensor is converted to a Celsius temperature value after eliminating lead resistance using a four-wire system; the temperatures of all PT100 platinum resistance sensors at the same sampling time are calculated. The arithmetic mean of the Celsius temperature values ​​corresponding to the sensors is used to obtain the temperature of the persimmon cold storage at the corresponding sampling time; the raw capacitance value collected by the capacitive humidity sensor is converted into a relative humidity value, and the median of the corresponding relative humidity values ​​collected by all capacitive humidity sensors at the same sampling time is taken as the humidity of the persimmon cold storage at the corresponding sampling time; the raw current signal collected by the electrochemical oxygen sensor is converted into a volume percentage; the raw absorbance collected by the nondispersive infrared carbon dioxide sensor is converted into ppm units; and the raw ion current collected by the photoionization ethylene sensor is converted into ppb or ppm units.

[0078] For each miniature sealed breathing chamber, during a 15-minute measurement cycle, the oxygen and carbon dioxide concentrations at the start and end of the closure were recorded. Based on the oxygen concentrations at the start and end of the closure, the oxygen consumption rate was calculated, and based on the carbon dioxide concentrations at the start and end of the closure, the carbon dioxide production rate was calculated. After unifying the oxygen consumption and carbon dioxide production rates to the same molar reference, the ratio of the carbon dioxide production rate to the oxygen consumption rate was calculated to obtain the respiratory quotient. For the impedance modulus and capacitance values ​​acquired by the interdigital electrode array, values ​​affected by electrode contact were discarded. Data on open and short circuits caused by defects, i.e., data with infinite impedance magnitude or impedance magnitude approaching 0; the impedance magnitude and capacitance values ​​measured at the time of storage for each batch of persimmons are used as reference values, and the impedance magnitude and capacitance values ​​obtained after each subsequent measurement are normalized based on these reference values, i.e., the ratio of each measured impedance magnitude and capacitance value to the corresponding reference value is calculated to obtain the normalized impedance magnitude and capacitance values; the raw absorbance array collected by the portable near-infrared spectrometer is subjected to standard normal variable transformation, Savitzky-Golay smoothing filtering, and first derivative processing in sequence to eliminate scattering effects caused by optical path differences, reduce high-frequency noise, and eliminate baseline drift.

[0079] The state extraction module performs feature extraction and state quantification on the cold storage environmental parameters and fruit physiological parameters to obtain a cold storage state vector. The cold storage state vector is composed of the cumulative chilling injury integral, respiration quotient, deastringency electrical index, near-infrared verification results, ethylene change rate, and acceleration. The cumulative chilling injury integral is used to quantify the degree of chilling injury risk caused by the cumulative exposure to low temperatures since the persimmons entered the storage. Its calculation method is as follows: set chilling injury weight coefficients corresponding to different temperature ranges, and perform weighted integration on the time series of cold storage temperatures based on the chilling injury weight coefficients to obtain the cumulative chilling injury integral.

[0080] Specifically, the chilling injury weighting coefficient is the equivalent value of chilling injury per unit time corresponding to different temperature ranges. Its physical meaning is the conversion factor of the accumulated chilling injury risk of persimmons for each hour of exposure within a given temperature range relative to the standard temperature range. The chilling injury weighting coefficient is dimensionless. The larger the chilling injury weighting coefficient, the higher the contribution of the corresponding temperature range to the chilling injury of persimmons.

[0081] In this embodiment, the chilling injury weighting coefficient is obtained through experimental calibration of Yangfeng persimmons: the same batch of persimmons is stored for the same amount of time in different constant temperature ranges. After being taken out of storage, the decrease in the browning rate of the pulp and the juice yield are detected. The decrease in the browning rate of the pulp and the juice yield are normalized to the maximum value and then added together to obtain the chilling injury effect of the corresponding temperature range. Taking the chilling injury effect of the temperature range with the most severe chilling injury, i.e., 2 to 5℃, as the benchmark value, the ratio of the chilling injury effect of the corresponding temperature range to the benchmark value is calculated to obtain the chilling injury weighting coefficient of the corresponding temperature range.

[0082] The respiratory quotient is used to characterize the current stage of the astringency removal process of the persimmon population. It is calculated by extracting the respiratory quotients of all micro-closed breathing chambers at the same time and calculating the arithmetic mean to obtain the respiratory quotient value at the corresponding time.

[0083] The de-astringency electrical index is used to quantify the progress of persimmon de-astringency completion. Its calculation method is as follows: The impedance modulus and capacitance values ​​of the persimmon at the point of complete de-astringency are obtained through experimental calibration, serving as the final impedance modulus and capacitance values; the difference between the baseline impedance modulus and the current impedance modulus is calculated, i.e., the baseline impedance modulus minus the current impedance modulus, yielding the first impedance modulus difference; the difference between the baseline impedance modulus and the final impedance modulus is also calculated, i.e., the baseline impedance modulus minus the final impedance modulus, yielding the second impedance modulus difference; the ratio of the first impedance modulus difference to the second impedance modulus difference is calculated, yielding the first ratio; the difference between the baseline capacitance and the current capacitance is then calculated. The process involves subtracting the current capacitance value from the baseline capacitance value to obtain the first capacitance difference, and then calculating the difference between the baseline capacitance value and the final capacitance value (i.e., subtracting the final capacitance value from the baseline capacitance value) to obtain the second capacitance difference. The ratio of the first capacitance difference to the second capacitance difference is then calculated to obtain the second ratio. Finally, a weighted sum of the first and second ratios is performed to obtain the de-astringency electrical index. The de-astringency electrical index ranges from 0 to 1, with a higher index indicating a higher degree of de-astringency completion. The weighting coefficients for the first and second ratios are set based on the sensitivity test calibration results of impedance modulus and capacitance value on changes in soluble tannin content during persimmon de-astringency.

[0084] Optionally, impedance modulus, capacitance, and soluble tannin content are collected periodically and synchronously from the same batch of persimmons; Pearson correlation coefficients of impedance modulus, capacitance, and soluble tannin content are calculated respectively, and the Pearson correlation coefficients are used as the basis for allocating weight coefficients. The larger the Pearson correlation coefficient, the larger the weight coefficient. Generally, impedance modulus and capacitance contribute equally to the astringency removal progress. Therefore, in this embodiment, the weight coefficients of the first ratio and the second ratio are both set to 0.5.

[0085] The near-infrared verification result is used to assist in verifying the completion of deastringency. It is obtained by: establishing a partial least squares model and inputting the original absorbance array after processing the first derivative into the partial least squares model to obtain the predicted value of soluble tannin content; if the predicted value of soluble tannin content is less than or equal to the preset content threshold, the near-infrared verification result is that deastringency is completed; otherwise, the near-infrared verification result is that deastringency is not completed.

[0086] In this embodiment, the partial least squares model is established as follows: At least 100 Yangfeng persimmons of the same variety and from the same origin are used as persimmon samples; these samples cover different maturity gradients from unripe to fully ripe; the raw absorbance array and soluble tannin content of each persimmon sample are simultaneously collected; the preprocessed raw absorbance array is used as the independent variable matrix X, and the measured soluble tannin content is used as the dependent variable vector Y; based on the principle of minimizing the sum of squared predicted residuals, leave-one-out cross-validation is used to determine the partial least squares model. The number of latent variable factors k; using the number of latent variable factors k as a parameter, a partial least squares regression algorithm is performed on the independent variable matrix X and the dependent variable vector Y. By iteratively extracting k pairs of latent variables, namely the score vector and the loading vector, the covariance of the latent variables is maximized; after extraction, the linear combination relationship between the original absorbance values ​​and the latent variables is reversed to obtain the regression coefficient vector and intercept term that directly map the original absorbance array to the predicted value of soluble tannin content, and the final partial least squares model is constructed based on the regression coefficient vector and intercept term.

[0087] The content threshold is set based on the correspondence between the sensory evaluation of imperceptible astringency in persimmons and the content of soluble tannins. In this embodiment, persimmon samples with different soluble tannin contents are selected and blindly tested by a trained professional sensory evaluation team to evaluate whether the astringency is perceptible or imperceptible. The sensory evaluation results and the chemically measured soluble tannin content are analyzed using receiver operating characteristic curves, and the soluble tannin content corresponding to the maximum Youden index is taken as the content threshold.

[0088] The ethylene change rate and acceleration are used to characterize the dynamic change trend of ethylene concentration in order to predict the risk of ethylene autocatalytic burst; the ethylene change rate is the first derivative of ethylene concentration with time, representing the speed of ethylene release; the acceleration is the first derivative of ethylene change rate with time, representing the degree of acceleration or deceleration of ethylene release.

[0089] The decision-making and early warning module performs collaborative decision-making and early warning based on the cold storage state vector and preset priority conditions, generating a control instruction set including stage switching instructions, cold damage intervention instructions, and ethylene intervention instructions; such as Figure 2 As shown, the collaborative decision-making and early warning method is as follows: if the cold storage state vector satisfies any priority condition, a corresponding control command is generated; otherwise, a corresponding stage switching command is generated according to the interval where the breathing quotient value is located, and a corresponding ethylene intervention command is generated according to the ethylene change rate and acceleration; the preset priority conditions from high to low are: forced out-of-warehouse condition, ethylene level 3 early warning condition, cold damage intervention condition, and de-astringency completion switching condition.

[0090] If the cumulative chilling injury score is greater than or equal to the preset chilling injury danger threshold, it is determined that the forced release condition is met, and a forced release chilling injury intervention instruction is directly generated. The chilling injury danger threshold is determined experimentally based on the maximum chilling injury accumulation that persimmon varieties can tolerate. That is, when the cumulative chilling injury score exceeds the chilling injury danger threshold, the marketability of persimmons after release is lower than the acceptable lower limit.

[0091] In this embodiment, several Yangfeng persimmons of the same variety, from the same origin, and at the same harvest maturity were randomly divided into multiple groups, with no fewer than 50 per group. Each group of persimmons was stored in a constant low-temperature environment, with the storage temperature covering the possible temperature range that persimmons might experience, such as -2℃ to 10℃. The storage time for each group was set at multiple levels, including 7 days, 14 days, 21 days, 28 days, and 35 days, to form a cross-experimental combination of different storage temperatures and storage times. After each group's experiment, the persimmons were transferred to a room-temperature environment for 3 days of post-ripening to simulate the shelf life after being taken out of storage. After post-ripening, relevant indicators of marketability were measured, including the rate of browning of the pulp and the decrease in juice yield. The acceptable taste score was used, and a commercialization rate standard was defined based on actual needs. The proportion of persimmons that met the commercialization rate standard in each experimental group was counted as a quantitative indicator of the degree of chilling injury tolerance of persimmons under the corresponding experimental conditions. The cumulative chilling injury integral was calculated simultaneously for each experimental group, and a scatter plot was drawn with the cumulative chilling injury integral as the horizontal axis and the proportion of persimmons that met the commercialization rate standard as the vertical axis. Logistic regression was performed on the scatter plot to obtain an S-shaped curve in which the proportion of persimmons that met the commercialization rate standard decreased as the cumulative chilling injury integral increased. The cumulative chilling injury integral corresponding to the point where the proportion of persimmons that met the commercialization rate standard dropped to the lower limit of actual acceptance was extracted from the S-shaped curve as the chilling injury danger threshold.

[0092] If the ethylene change rate is greater than or equal to the preset ethylene level 3 warning change rate threshold, or the ethylene concentration is greater than or equal to the preset ethylene level 3 warning concentration threshold, then the ethylene level 3 warning condition is met, and an ethylene emergency intervention command is generated. The ethylene level 3 warning change rate threshold is determined based on the critical change rate experiment of ethylene autocatalytic burst in persimmons, that is, after exceeding the ethylene level 3 warning change rate threshold, the autocatalytic effect will be irreversibly started. The ethylene level 3 warning concentration threshold is determined based on the upper limit of the sensitivity concentration of ethylene in persimmons, that is, after exceeding the ethylene level 3 warning concentration threshold, the aging rate of the persimmon population is significantly accelerated.

[0093] In this embodiment, the calibration method for the ethylene level-three warning change rate threshold is as follows: A number of Yangfeng persimmons of the same variety, from the same origin, and at the same harvest maturity are selected and stored under standard cold storage conditions. The standard cold storage conditions are: temperature 6±1℃, humidity 85%RH to 90%RH, oxygen concentration 3% to 4%, and carbon dioxide concentration 10000ppm to 20000ppm. Multiple experimental groups are set up, and ethylene gas is artificially injected into the cold storage environment during the peak period of persimmon astringency removal, causing the ethylene concentration to increase at different rate gradients. For each experimental group, after the artificial injection of ethylene gas, the ethylene concentration and persimmon quality indicators, including pulp firmness, soluble tannin content, and respiration rate, are monitored. The trend of ethylene release rate was studied, and the irreversible start-up of the autocatalytic effect was used as the criterion to determine whether irreversible start-up occurred in each experimental group. The irreversible start-up of the autocatalytic effect was defined as follows: after the artificial injection of ethylene gas was stopped, the ethylene concentration continued to rise and the ethylene change rate was always greater than 0.3 ppb / h in the following 4 hours, while the respiration rate and ethylene release rate showed a second peak. Logistic regression fitting was performed with the ethylene change rate on the horizontal axis and the occurrence rate of irreversible start-up on the vertical axis, and the ethylene change rate corresponding to the irreversible start-up occurrence rate reaching 50% was taken as the critical change rate. In order to leave a safety margin, the threshold of the ethylene three-level warning change rate was set to 70% to 80% of the critical change rate.

[0094] In this embodiment, the calibration method for the ethylene level-three warning concentration threshold is as follows: several Yangfeng persimmons of the same variety, from the same origin, and at the same harvest maturity are randomly divided into multiple groups, with no less than 50 persimmons in each group; each group of persimmons is stored in a sealed environment with a different constant ethylene concentration, while keeping other environmental parameters consistent; after being stored in the sealed environment for 72 hours, the persimmons are taken out and transferred to a normal environment with an ethylene concentration of less than 0.05 ppm, and the changes in the persimmon pulp softening rate, pedicel abscission rate, peak respiration rate, and soluble solids content are observed and detected. The criteria for significantly accelerated aging rate were defined, and the proportion of significantly accelerated aging rate in each experimental group was statistically analyzed. The criteria for significantly accelerated aging rate were: compared with the control group with ethylene concentration less than 0.05 ppm, the softening rate increased by more than 50%, or the peak respiration rate increased by more than 100%, or the fruit stalk abscission rate increased by more than 20%. A logistic regression curve was fitted with ethylene concentration as the horizontal axis and the proportion of significantly accelerated aging rate as the vertical axis, and the ethylene concentration corresponding to the proportion of significantly accelerated aging rate reaching 50% was taken as the ethylene level three warning concentration threshold.

[0095] If the cumulative chilling injury integral is greater than or equal to the preset chilling injury intervention threshold, and the ethylene level 3 early warning conditions are not met, then the chilling injury intervention conditions are determined to be met, and a chilling injury intervention command for temperature recovery is generated; the chilling injury intervention threshold is determined according to experimental calibration, and this threshold is the maximum cumulative chilling injury integral value that can effectively reverse the chilling injury process through temperature recovery treatment.

[0096] In this embodiment, several Yangfeng persimmons of the same variety, from the same origin, and at the same harvest maturity were randomly divided into multiple groups, with no fewer than 100 persimmons in each group. Each group of persimmons was stored in a constant low-temperature environment for different durations, so that the cumulative chilling injury integral of each group reached different target values, such as 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, and 4.5. Experimental and control groups were set up, and each experimental group underwent a temperature recovery treatment: the storage temperature was raised to 10±0.5℃ and maintained for 6 hours, then lowered back to the original storage temperature at a rate of 0.5℃ / h. All experimental groups... After storage, the persimmons in both the experimental and control groups were transferred to room temperature for 3 days of post-ripening. After the post-ripening period, the decrease in the browning rate of the persimmon pulp and the juice yield were measured. The sum of the decrease in the browning rate of the pulp and the juice yield was calculated to obtain the chilling injury comprehensive index of the persimmon. For each target value of the chilling injury cumulative score, the ratio of the chilling injury comprehensive index of the experimental group to that of the control group was calculated, and a relationship curve between the target value of the chilling injury cumulative score and the ratio was plotted. The target value of the chilling injury cumulative score corresponding to when the chilling injury comprehensive index of the experimental group does not exceed 60% of that of the control group was extracted from the relationship curve as the chilling injury intervention threshold.

[0097] If the respiratory quotient value is less than the preset respiratory quotient threshold for astringency completion, and the duration is greater than or equal to the preset stabilization time threshold, and the astringency electrical index is greater than or equal to the preset astringency completion electrical threshold, and the near-infrared verification result indicates astringency completion, then the astringency completion switching condition is met, and a stage switching command to switch to the stable storage stage is generated. The stable storage stage refers to the long-term storage stage set after the persimmon has completed astringency removal, in order to inhibit further ripening and senescence of the fruit and extend the shelf life of the product. The astringency completion respiratory quotient threshold is determined based on the characteristic value of the respiratory quotient of the persimmon returning to a state dominated by aerobic respiration after astringency removal. The stabilization time threshold is determined based on the physiological response inertia of the persimmon and the sensor measurement cycle to ensure the reliability of the judgment. The astringency completion electrical threshold is set based on the degree of change of the impedance modulus and capacitance value of the persimmon relative to the reference value when astringency is completely removed.

[0098] The specific method for generating corresponding stage switching instructions based on the respiratory quotient interval is as follows: when the respiratory quotient value is less than the preset deastringency initiation threshold, the persimmon is determined to be in the deastringency initiation period, and a stage switching instruction to switch to the deastringency initiation period is generated; when the respiratory quotient value is greater than or equal to the deastringency initiation threshold and less than the preset deastringency acceleration threshold, the persimmon is determined to be in the deastringency acceleration period, and a stage switching instruction to switch to the deastringency acceleration period is generated; when the respiratory quotient value is greater than or equal to the deastringency acceleration threshold and less than the preset deastringency peak threshold, the persimmon is determined to be in the deastringency peak period, and a stage switching instruction to switch to the deastringency peak period is generated; the stage switching instruction includes the temperature setting value and tolerance, oxygen concentration setting value, carbon dioxide concentration range, and humidity range corresponding to the deastringency stage.

[0099] Optionally, if the respiratory quotient is greater than or equal to the deastringency peak threshold and the deastringency completion switching condition is not met, the system maintains the current deastringency peak period stage switching instruction unchanged, triggers a deastringency process abnormality warning, and notifies the management personnel to check.

[0100] In this embodiment, the de-astringency initiation threshold, de-astringency acceleration threshold, and de-astringency peak threshold are set as follows: Yangfeng persimmon samples of the same variety and origin are selected, and the respiratory quotient is measured periodically under standard cold storage conditions, while the soluble tannin content is detected simultaneously to determine the actual progress of de-astringency; a respiratory quotient evolution curve is plotted with time as the horizontal axis and respiratory quotient as the vertical axis, and characteristic inflection points on the respiratory quotient evolution curve are identified; the respiratory quotient corresponding to the starting point where the respiratory quotient starts to rise significantly from close to 1.0 is taken as the de-astringency initiation threshold; the respiratory quotient corresponding to the turning point after the respiratory quotient enters the rapid rise stage is taken as the de-astringency acceleration threshold; and the respiratory quotient corresponding to the upper boundary before the respiratory quotient reaches its peak and tends to stabilize or begins to fall is taken as the de-astringency peak threshold.

[0101] The temperature setpoints and tolerances, oxygen concentration setpoints, and carbon dioxide concentration ranges are set based on the physiological needs of persimmons for temperature, humidity, and gas environment at different stages of astringency removal, the requirements for avoiding chilling injury, and the experimental calibration results for balancing astringency removal efficiency and quality maintenance. Specifically, during the de-astringency initiation period, a lower temperature is needed to suppress respiration intensity while inducing de-astringency initiation. The temperature setpoint must balance the dual requirements of avoiding chilling injury and inducing de-astringency. Although 2 to 5°C is the temperature range with the most severe chilling injury accumulation in long-term storage experiments, the exposure time to this temperature range during the de-astringency initiation period is relatively short. Moreover, low temperatures of around 4°C have been experimentally verified to effectively suppress respiration intensity and induce de-astringency initiation without causing chilling injury symptoms under short-term exposure. Therefore, the temperature setpoint during the de-astringency initiation period can be set for a short period in the low-temperature range of the chilling injury sensitive zone. During the de-astringency acceleration period, the temperature needs to be moderately increased to promote respiratory metabolism and soluble tannin polymerization. The temperature setpoint must ensure that it does not trigger chilling injury or accelerate aging. During the peak de-astringency period, the oxygen and carbon dioxide ratio needs to be further optimized to accelerate de-astringency and suppress excessive respiration, while avoiding excessive carbon dioxide leading to anaerobic damage. The tolerance of each de-astringency stage is determined jointly based on the persimmon's tolerance to parameter fluctuations and the control precision of the actual refrigeration and controlled atmosphere equipment to ensure that the cold storage environment can still meet the de-astringency requirements within a reasonable fluctuation range.

[0102] In this embodiment, the temperature setting for the deastringency start-up period is 4±1℃, the oxygen concentration setting is 2±1%, the carbon dioxide concentration range is 3000ppm to 10000ppm, and the humidity range is 85%RH to 90%RH; the temperature setting for the deastringency acceleration period is 5.5±1.5℃, the oxygen concentration setting is 3±1%, the carbon dioxide concentration range is 5000ppm to 15000ppm, and the humidity range is 85% to 90%RH; the temperature setting for the deastringency peak period is 6.5±1.5℃, the oxygen concentration setting is 3.5±1%, the carbon dioxide concentration range is 10000ppm to 20000ppm, and the humidity range is 85%RH to 90%RH.

[0103] When the ethylene change rate is greater than or equal to the preset ethylene level 1 warning change rate threshold and less than the ethylene level 3 warning change rate threshold, it is determined that the ethylene level 1 warning condition is met, and an ethylene level 1 intervention command is generated; the ethylene level 1 intervention command includes increasing the ventilation frequency to once every 2 hours and starting the ozone generator to release 0.2 ppm ozone for 30 minutes.

[0104] When the ethylene change rate is greater than or equal to the preset ethylene secondary warning change rate threshold, or the ethylene acceleration is greater than or equal to the preset ethylene acceleration warning threshold, the ethylene secondary warning condition is determined to be met, and an ethylene secondary intervention command is generated.

[0105] Optionally, if both the ethylene level II warning condition and the ethylene level I warning condition are met simultaneously, then the ethylene level II warning condition shall be followed; the ethylene level I intervention command and the ethylene level II intervention command shall be executed together with the phase switching command of the same period.

[0106] The threshold values ​​for the first-level and second-level ethylene warning rate changes were determined experimentally based on the correlation between the ethylene change rate and the degree of accelerated aging of persimmons; the threshold value for the ethylene acceleration warning was determined statistically based on the significance of the accelerated trend of ethylene release. In this embodiment, the threshold values ​​for the first-level and second-level ethylene warning change rates are determined as follows: Several Yangfeng persimmons of the same variety, from the same origin, and at the same harvest maturity are selected and stored in a standard cold storage until the peak astringency removal period. Ethylene gas is artificially injected into the cold storage environment, and multiple experimental groups are set up. The ethylene concentration in each group is increased at a different constant rate of change, and this constant rate of change is maintained for 4 hours. Within 24 hours after the artificial injection of ethylene gas, the aging acceleration-related indicators of the persimmons are detected every 2 hours, including the rate of pulp softening, the rate of pedicel abscission, and the peak change in respiration rate. The arithmetic mean of the aging acceleration-related indicators is calculated as the aging acceleration score. A scatter plot is drawn with the ethylene change rate on the horizontal axis and the aging acceleration score on the vertical axis, and logistic regression is performed. The ethylene change rate corresponding to an aging acceleration score of 0.3 is taken as the threshold value for the first-level ethylene warning change rate. The ethylene change rate corresponding to an aging acceleration score of 0.6 is taken as the threshold value for the second-level ethylene warning change rate. The method for determining the ethylene acceleration warning threshold is as follows: Select several Yangfeng persimmons of the same variety, origin, and harvest maturity, and store them under standard cold storage conditions until the peak period of astringency removal; artificially inject ethylene gas into the cold storage environment to increase the ethylene concentration at different constant acceleration rates until the ethylene concentration reaches 0.5 ppm and then stop the injection; after stopping the injection, monitor the proportion of ethylene change rate still greater than 0.2 ppb / h within 2 hours, and use it as the acceleration trend significance index; plot a scatter plot with ethylene acceleration as the horizontal axis and acceleration trend significance index as the vertical axis, perform logistic regression fitting, and take the ethylene acceleration corresponding to the acceleration trend significance index of 50% as the ethylene acceleration warning threshold.

[0107] The execution control module is used to drive the actuators to execute the control commands in the control command set; the actuators include a refrigeration unit, a humidifier, a dehumidifier, a controlled atmosphere valve, a ventilation fan, an ozone generator, a 1-methylcyclopropene slow-release device, and a temperature recovery heater; each actuator is electrically connected to the execution control module.

[0108] If the control command is a forced release from the cold storage to intervene in cold damage, an audible and visual alarm will be issued, all control command execution will be stopped, and a release notification will be sent to the cold storage management system.

[0109] If the control command is an ethylene emergency intervention command, the 1-methylcyclopropene slow-release device is activated to release 1-methylcyclopropene at a preset dose, and a cooling command is sent to the refrigeration unit to reduce the current temperature of the persimmon cold storage by a preset cooling range, while ensuring that the temperature of the persimmon cold storage after the reduction is not lower than the preset minimum temperature limit. At the same time, the ventilation fan is activated to perform forced ventilation for a preset ventilation duration.

[0110] In this embodiment, the preset dosage is calibrated based on the response concentration experiment of persimmon to 1-methylcyclopropene. Specifically, different dosages of 1-methylcyclopropene are used to treat persimmons of the same variety and maturity level. The decrease in ethylene release rate and the effect on maintaining fruit quality after treatment are measured, and the minimum effective dosage that inhibits ethylene without causing phytotoxicity is taken as the preset dosage. The preset cooling range is calibrated based on experiments on the rate of temperature decrease that persimmons can tolerate in the short term and the effect of temperature abrupt changes on respiration intensity. Specifically, the maximum allowable cooling step size that can effectively reduce ethylene synthase activity is taken as the preset cooling range, provided that chilling injury or respiratory stress is not triggered. The preset minimum temperature limit is calibrated based on experiments on the critical chilling injury temperature of persimmon varieties. Specifically, the minimum temperature limit is the lowest safe temperature at which persimmons will not suffer chilling injury during long-term storage, ensuring that cooling intervention will not cause the temperature in the cold storage to fall into the chilling injury sensitive range of 2°C to 15°C or below the freezing point, resulting in frost damage. The preset ventilation time is determined experimentally based on the space volume of the persimmon cold storage, the air exchange efficiency of the ventilation fan, and the time required to dilute the ethylene concentration to a safe level. In other words, the preset ventilation time is a reasonable duration that can ensure rapid replacement of the high-ethylene air in the storage while avoiding drastic fluctuations in temperature and humidity due to prolonged ventilation.

[0111] If the control command is a cold damage intervention command for temperature recovery, then the temperature recovery heater is activated to raise the temperature of the persimmon cold storage to the preset temperature recovery target temperature, and after maintaining the temperature rise for a preset duration, the refrigeration unit is controlled to return to the target temperature set value of the current stage at a preset rate of temperature reduction.

[0112] In this embodiment, the preset target temperature for warming recovery is determined experimentally based on the optimal temperature range for heat treatment to reverse chilling injury in persimmons: persimmons that have experienced accumulated chilling injury are subjected to short-term heat treatment at different temperatures, and the recovery rate of pulp browning, juice yield, and respiration rate after heat treatment is detected. The temperature at which the chilling injury reversal effect is optimal without triggering secondary heat stress is taken as the preset target temperature for warming recovery. The preset duration of warming maintenance is determined experimentally based on the heat accumulation time required for persimmons to achieve chilling injury reversal and to avoid excessive warming leading to quality deterioration: different maintenance durations are set for warming treatment, and the reduction in the comprehensive chilling injury index and the retention of pulp firmness and soluble solids are detected after warming treatment. The shortest duration at which extending the maintenance time no longer significantly improves chilling injury is taken as the preset duration of warming maintenance. The preset cooling rate is determined based on the persimmon's tolerance to temperature changes and experimental calibration to avoid respiratory rebound or secondary chilling injury caused by sudden temperature changes: different cooling rates are set to restore the target temperature from heating to the original storage temperature, and the changes in ethylene release rate, respiration intensity and chilling injury comprehensive index are monitored during the cooling process. The maximum safe cooling rate that does not trigger a respiration jump and ethylene autocatalytic release is taken as the preset cooling rate.

[0113] If the control command is a stage switching command, then the temperature setpoint and tolerance, oxygen concentration setpoint, carbon dioxide concentration range, and humidity setpoint are parsed from the stage switching command; the opening of the refrigerant valve of the refrigeration unit is adjusted by the PID controller to bring the temperature of the persimmon cold storage to within the tolerance range of the temperature setpoint; the oxygen concentration is brought closer to the oxygen concentration setpoint and the carbon dioxide concentration is kept within the carbon dioxide concentration range by adjusting the atmosphere valve; the humidity of the persimmon cold storage is brought closer to the humidity setpoint by adjusting the humidifier or dehumidifier.

[0114] If the control command is an ethylene level 1 intervention command, the ventilation fan's air exchange frequency will be increased to a preset level 1 air exchange frequency, and the ozone generator will be started to release a preset level 1 ozone concentration for a preset level 1 ozone treatment duration.

[0115] In this embodiment, the preset primary ventilation frequency is calibrated through experiments on the spatial volume of the persimmon cold storage and the dilution kinetics of ethylene: tracer gas, such as sulfur hexafluoride, is injected into the persimmon cold storage, and the gas concentration decay curves at different ventilation frequencies are tested. The minimum number of ventilations required to reduce the ethylene concentration by 30% within 30 minutes is calculated, and the ventilation frequency corresponding to the minimum number of ventilations is taken as the primary ventilation frequency. The preset primary ozone concentration is calibrated based on experiments on the decomposition efficiency of ozone on ethylene and the safety threshold of no damage to the persimmon peel: ozone treatment groups with different concentrations of 0.1ppm, 0.2ppm, 0.3ppm, and 0.5ppm are set. After 30 minutes of treatment, the ethylene degradation rate is measured, and the damage to oil cells, color changes, and respiration rate of the peel are observed within 24 hours after ozone treatment. The highest concentration with an ethylene degradation rate of not less than 60% and no visible damage is taken as the primary ozone concentration. The preset first-level ozone treatment duration is determined as follows: the time it takes for the ozone concentration in the persimmon cold storage to reach the first-level ozone concentration after the ozone generator is started, and the time required for the ozone to naturally decay to 0.05 ppm after the ozone generator is stopped; the curve of ethylene concentration changing with treatment time is measured, and the shortest time required for the ethylene concentration to drop to 70% of the pre-treatment level is taken; the first-level ozone treatment duration is set as the shortest time, and the first-level ozone treatment duration shall not exceed the time required for the ozone to naturally decay to 0.05 ppm after the ozone generator is stopped.

[0116] If the control command is an ethylene secondary intervention command, the oxygen concentration will be reduced by a preset secondary oxygen reduction rate and the carbon dioxide concentration will be increased by a preset secondary carbon dioxide increase rate through the atmosphere control valve. At the same time, the ventilation frequency of the ventilation fan will be increased to a preset secondary ventilation frequency. If both an ethylene primary intervention command and an ethylene secondary intervention command are received at the same time, the ethylene secondary intervention command will be executed.

[0117] In this embodiment, the preset secondary oxygen reduction rate is determined as follows: experimental groups with oxygen concentrations reduced by 0.3%, 0.5%, 0.7%, and 1.0% respectively are set up, and after maintaining this for 4 hours, the decrease in ethylene release rate and the respiration quotient are measured; the maximum decrease in ethylene release rate of not less than 40% and the respiration quotient of less than 1.5 is taken as the preset secondary oxygen reduction rate. The preset secondary carbon dioxide increase rate is determined as follows: carbon dioxide concentrations are increased by 1000ppm, 2000ppm, 3000ppm, and 4000ppm respectively, and after maintaining this for 4 hours, the decrease in ethylene change rate, fruit pulp browning rate, and off-odor generation are measured; the minimum increase in ethylene change rate of greater than or equal to 30% and without browning or off-odor is taken as the preset secondary carbon dioxide increase rate. The calibration method for the preset secondary ventilation frequency is as follows: different ventilation frequencies are used in the persimmon cold storage, and the rate of decrease of ethylene concentration and the fluctuation range of temperature and humidity are measured at each ventilation frequency; the minimum ventilation frequency that can reduce the ethylene concentration to a safe level within the emergency response time and whose temperature and humidity fluctuations do not exceed the minimum allowable ventilation frequency of the cold storage is selected as the preset secondary ventilation frequency.

[0118] Example 2

[0119] This embodiment is the second embodiment of this application; it is based on the same inventive concept as Embodiment 1, and refers to... Figure 3 This embodiment introduces a cold storage control method based on gradient temperature control, including the following steps:

[0120] The cold storage environmental parameters and fruit physiological parameters were collected and preprocessed. The cold storage environmental parameters included wind speed, temperature, humidity, oxygen concentration, carbon dioxide concentration and ethylene concentration in the persimmon cold storage. The fruit physiological parameters included respiratory quotient, electrical parameters and near-infrared spectrum.

[0121] Feature extraction and state quantification are performed on the cold storage environmental parameters and fruit physiological parameters to obtain a cold storage state vector; the cold storage state vector consists of the cumulative integral of chilling injury, respiration quotient, deacidification electrical index, near-infrared verification results, ethylene change rate and acceleration.

[0122] Based on the cold storage state vector and preset priority conditions, collaborative decision-making and early warning are performed to generate a control instruction set that includes stage switching instructions, cold damage intervention instructions and ethylene intervention instructions, and drive the actuator to execute the control instructions in the control instruction set.

[0123] The collaborative decision-making and early warning method is as follows: if the cold storage state vector satisfies any priority condition, a corresponding control command is generated; otherwise, a corresponding stage switching command is generated according to the interval where the breathing quotient value is located, and a corresponding ethylene intervention command is generated according to the ethylene change rate and acceleration; the preset priority conditions are in the following order from high to low: forced out-of-warehouse condition, ethylene level 3 early warning condition, cold damage intervention condition, and de-astringency completion switching condition.

[0124] The specific functions of each step described above are explained in the relevant content of the gradient temperature control system for cold storage described in Example 1, and will not be repeated here.

[0125] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0126] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of protection of this application, and these forms are all within the protection scope of this application.

Claims

1. A cold storage control system based on gradient temperature control, characterized in that, It includes a data acquisition module, a status extraction module, a decision-making and early warning module, and an execution and control module; The data acquisition module is used to collect cold storage environmental parameters and fruit physiological parameters, and to preprocess the cold storage environmental parameters and fruit physiological parameters; The state extraction module performs feature extraction and state quantification on the cold storage environmental parameters and fruit physiological parameters to obtain a cold storage state vector; the cold storage state vector consists of the cumulative integral of chilling injury, respiration quotient, deacidification electrical index, near-infrared verification results, ethylene change rate and acceleration. The decision-making and early warning module makes collaborative decisions and issues early warnings based on the cold storage state vector and preset priority conditions, generating a control instruction set that includes stage switching instructions, cold damage intervention instructions, and ethylene intervention instructions. The execution control module is used to drive the actuator to execute the control instructions in the control instruction set.

2. The cold storage control system based on gradient temperature control as described in claim 1, characterized in that, The state extraction module is configured with a cold damage cumulative integral calculation strategy, specifically including: After storing the same batch of fruit for the same period of time in different constant temperature ranges, the decrease in pulp browning rate and juice yield was detected. The decrease in pulp browning rate and juice yield was normalized and then summed to obtain the chilling injury effect of the corresponding temperature range. Using the chilling injury effect of the temperature range with the most severe chilling injury as the benchmark value, the ratio of the chilling injury effect of each temperature range to the benchmark value is calculated to obtain the chilling injury weighting coefficient of the corresponding temperature range. The cumulative integral of the cold damage is obtained by weighting and integrating the time series of the cold storage temperature based on the aforementioned cold damage weighting coefficient.

3. The cold storage control system based on gradient temperature control as described in claim 2, characterized in that, The state extraction module is also configured with a de-abrasion electrical index calculation strategy, specifically including: The impedance modulus and capacitance values ​​of the fruit when it is completely de-astringent were obtained through experimental calibration, and were used as the final values ​​of impedance modulus and capacitance. The impedance modulus and capacitance values ​​measured when the fruit was put into storage were used as the reference values. Calculate the difference between the reference value of the impedance magnitude and the current impedance magnitude to obtain the first difference of the impedance magnitude, and calculate the difference between the reference value of the impedance magnitude and the final value of the impedance magnitude to obtain the second difference of the impedance magnitude. Calculate the ratio of the first difference in impedance magnitude to the second difference in impedance magnitude to obtain the first ratio; Calculate the difference between the reference value and the current capacitance value to obtain the first difference in capacitance value, and calculate the difference between the reference value and the final value of capacitance value to obtain the second difference in capacitance value; Calculate the ratio of the first difference in capacitance value to the second difference in capacitance value to obtain the second ratio; perform a weighted summation of the first ratio and the second ratio to obtain the decoupling electrical index.

4. The cold storage control system based on gradient temperature control as described in claim 3, characterized in that, The state extraction module is also configured with a near-infrared verification result acquisition strategy, specifically including: The original absorbance array was processed by first-order derivative, and a partial least squares model was established. The original absorbance array after processing the first derivative is input into the partial least squares model to obtain the predicted value of soluble tannin content. If the predicted soluble tannin content is less than or equal to the preset content threshold, the near-infrared verification result indicates that deacidification is complete; otherwise, the near-infrared verification result indicates that deacidification is incomplete.

5. A cold storage control system based on gradient temperature control as described in claim 1, characterized in that, The decision-making and early warning module is configured with collaborative decision-making and early warning strategies, specifically including: If the cold storage state vector satisfies any priority condition, then the corresponding control command is generated; Otherwise, a corresponding stage switching instruction is generated based on the interval of the respiratory quotient value, and a corresponding ethylene intervention instruction is generated based on the ethylene change rate and acceleration. The preset priority conditions, from high to low, are: forced warehouse exit condition, ethylene level 3 early warning condition, cold damage intervention condition, and de-abrasion completion switching condition; The ethylene intervention command is executed together with the phase switching command during the same period.

6. A cold storage control system based on gradient temperature control as described in claim 5, characterized in that, The method for determining the forced release condition is as follows: if the cumulative cold damage score is greater than or equal to the preset cold damage danger threshold, then the forced release condition is determined to be met, and a forced release cold damage intervention command is generated. The determination method for the ethylene level 3 warning condition is as follows: if the ethylene change rate is greater than or equal to the preset ethylene level 3 warning change rate threshold, or the ethylene concentration is greater than or equal to the preset ethylene level 3 warning concentration threshold, then the ethylene level 3 warning condition is determined to be met, and an ethylene emergency intervention command is generated.

7. A cold storage control system based on gradient temperature control as described in claim 5, characterized in that, The method for determining the cold damage intervention conditions is as follows: if the cumulative cold damage integral is greater than or equal to the preset cold damage intervention threshold, and the ethylene level 3 early warning conditions are not met, then the cold damage intervention conditions are determined to be met, and a cold damage intervention command for warming recovery is generated. The method for determining the desiccation completion switching condition is as follows: if the respiratory quotient value is less than the preset desiccation completion respiratory quotient threshold, and the duration is greater than or equal to the preset stable duration threshold, and the desiccation electrical index is greater than or equal to the preset desiccation completion electrical threshold, and the near-infrared verification result is desiccation completion, then it is determined that the desiccation completion switching condition is met, and a stage switching instruction to switch to the stable storage stage is generated.

8. A cold storage control system based on gradient temperature control as described in claim 5, characterized in that, The specific method for generating corresponding stage switching instructions based on the respiratory quotient value range is as follows: When the respiratory quotient value is less than the preset deastringency initiation threshold, the fruit is determined to be in the deastringency initiation period, and a stage switching instruction to switch to the deastringency initiation period is generated. When the respiratory quotient is greater than or equal to the de-astringency initiation threshold and less than the preset de-astringency acceleration threshold, the fruit is determined to be in the de-astringency acceleration period, and a stage switching instruction to switch to the de-astringency acceleration period is generated. When the respiratory quotient is greater than or equal to the de-astringency acceleration threshold and less than the preset de-astringency peak threshold, the fruit is determined to be in the de-astringency peak period, and a stage switching instruction to switch to the de-astringency peak period is generated. The stage switching command includes the temperature setting value and tolerance, oxygen concentration setting value, carbon dioxide concentration range and humidity range corresponding to the deacidification stage.

9. A cold storage control system based on gradient temperature control as described in claim 5, characterized in that, The specific method for generating corresponding ethylene intervention commands based on the ethylene change rate and acceleration is as follows: When the ethylene change rate is greater than or equal to the preset ethylene level 1 warning change rate threshold and less than the ethylene level 3 warning change rate threshold, the ethylene level 1 warning condition is met, and an ethylene level 1 intervention command is generated. When the ethylene change rate is greater than or equal to the preset ethylene level 2 warning change rate threshold, or the ethylene acceleration is greater than or equal to the preset ethylene acceleration warning threshold, the ethylene level 2 warning condition is determined to be met, and an ethylene level 2 intervention command is generated. If both the Level II and Level I warning conditions for ethylene are met simultaneously, then the Level II warning condition shall apply.

10. A cold storage control system based on gradient temperature control as described in claim 1, characterized in that, The execution control module is configured with a control instruction execution strategy to drive the actuator to execute control instructions from the control instruction set; the control instruction execution strategy specifically includes: The actuators include a refrigeration unit, a humidifier, a dehumidifier, a controlled atmosphere valve, a ventilation fan, an ozone generator, a 1-methylcyclopropene slow-release device, and a temperature recovery heater; each actuator is electrically connected to the execution control module. If the control command is a forced release from the cold storage to intervene in cold damage, an audible and visual alarm will be issued, all control command execution will be stopped, and a release notification will be sent to the cold storage management system.

11. A cold storage control system based on gradient temperature control as described in claim 10, characterized in that, The control command execution strategy also includes: If the control command is an ethylene emergency intervention command, then the 1-methylcyclopropene slow-release device is activated to release 1-methylcyclopropene at a preset dose, and a cooling command is sent to the refrigeration unit. At the same time, the ventilation fan is activated to perform forced ventilation for a preset ventilation duration. If the control command is a cold damage intervention command for temperature recovery, then the temperature recovery heater is activated to raise the temperature of the cold storage to the preset temperature recovery target temperature, and after maintaining the temperature rise for a preset duration, the refrigeration unit is controlled to return to the target temperature set value of the current stage at a preset rate of temperature reduction.

12. A cold storage control system based on gradient temperature control as described in claim 11, characterized in that, The control command execution strategy also includes: If the control command is a stage switching command, the opening of the refrigerant valve of the refrigeration unit is adjusted by the PID controller to keep the temperature of the cold storage within the tolerance range of the temperature set value. By adjusting the gas control valve, the oxygen concentration is made to reach the set oxygen concentration value, and the carbon dioxide concentration is kept within the carbon dioxide concentration range. By adjusting the humidifier or dehumidifier, the humidity of the cold storage can be brought to the set humidity value.

13. A cold storage control system based on gradient temperature control as described in claim 12, characterized in that, The control command execution strategy also includes: If the control command is an ethylene level 1 intervention command, the ventilation fan's air exchange frequency will be increased to a preset level 1 air exchange frequency, and the ozone generator will be started to release a preset level 1 ozone concentration for a preset level 1 ozone treatment duration. If the control command is an ethylene secondary intervention command, the oxygen concentration will be reduced by a preset secondary oxygen reduction rate through the atmosphere control valve, and the carbon dioxide concentration will be increased by a preset secondary carbon dioxide increase rate. At the same time, the ventilation frequency of the ventilation fan will be increased to a preset secondary ventilation frequency.

14. A cold storage control method based on gradient temperature control, implemented based on the cold storage control system based on gradient temperature control according to any one of claims 1-13, characterized in that, Includes the following steps: Collect cold storage environmental parameters and fruit physiological parameters, and preprocess the cold storage environmental parameters and fruit physiological parameters; Feature extraction and state quantization are performed on the cold storage environmental parameters and fruit physiological parameters to obtain the cold storage state vector; The cold storage state vector consists of the cumulative integral of cold damage, the respiration quotient, the de-astringency electrical index, the near-infrared verification results, the ethylene change rate and acceleration. Based on the cold storage state vector and preset priority conditions, collaborative decision-making and early warning are performed to generate a control instruction set that includes stage switching instructions, cold damage intervention instructions and ethylene intervention instructions, and drive the actuator to execute the control instructions in the control instruction set.

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