A post-ripening fruit ripening environment ethylene online detection system, method and computer readable storage medium

Abstract

The present application belongs to the technical field of environmental gas detection, and particularly relates to a post-ripening fruit ripening environment ethylene online detection system, method and computer readable storage medium. The system comprises a multi-point sampling loop, a controlled disturbance excitation unit and a controller. The system collects gas through main flow, near wall and near fruit pile gas inlets at different times, applies forward and reverse disturbance excitation, extracts peak overshoot and recovery time constant, and realizes ethylene source decoupling determination based on the constructed intensity index model to distinguish wall memory release, fruit endogenous gas release and uniform residue. The present application can accurately identify different sources of ethylene, eliminate boundary layer interference, improve the accuracy of concentration detection in the ripening environment, guarantee the quality of fruit ripening, and adapt to various ripening spaces and working conditions.

Description

Technical Field

[0001] This invention belongs to the field of environmental gas detection technology, specifically relating to an online detection system, method, and computer-readable storage medium for ethylene in the ripening environment of post-ripening fruits. Background Technology

[0002] Post-ripening fruits (such as bananas, mangoes, kiwis, avocados, papayas, and persimmons) require a controlled ripening process after harvest to achieve uniform and optimal edible quality. The ethylene concentration within the ripening space is the core criterion for initiating the ripening process, adjusting parameters, switching processes, and terminating operations. The accuracy and interpretability of its detection directly determine the consistency of ripening operations, the rate of high-quality fruit, and the post-harvest loss rate.

[0003] Currently, ethylene detection solutions for ripening environments mainly fall into two categories: the first is a single-point static detection solution, which uses a single detection point or a single-path sampling port within the ripening space, combined with an electrochemical or infrared ethylene sensor, to detect the overall ethylene concentration within the ripening space; the second is a multi-channel sampling detection solution, which uses multiple sampling points, combined with multi-channel valve groups and multiple sensors, to detect ethylene concentration at multiple points within the ripening space, thus solving the problem of insufficient representativeness of the overall ethylene concentration output from single-point static detection. Both of these ethylene detection solutions, combined with zero-point calibration and background compensation, can further address zero-point drift within the sensor itself and between multiple sensors, as well as cross-interference from other volatile gases, by adding a zero-calibration branch and a cross-interference compensation algorithm.

[0004] However, in the actual ripening process, the ethylene in the ripening space does not originate from a single source, but rather from three sources simultaneously: first, residual ethylene that was not completely discharged after previous batches and forms a uniformly dispersed distribution within the ripening space; second, memory ethylene, which is reversibly adsorbed onto the walls of the ripening space, the inner walls of the air ducts, the lining, the packaging materials, and the surface of the turnover baskets, and is released again under external stimuli such as airflow disturbances; and third, endogenous ethylene, which is continuously produced and released during the fruit's own ripening physiological metabolism. These three sources of ethylene correspond to completely different control directions and operational strategies in the ripening process. Among them, endogenous ethylene is the core indicator for detecting whether the fruit has entered the ripening process.

[0005] However, existing ethylene detection methods can only output the total ethylene concentration and cannot distinguish the specific source of ethylene. This leads to distortion of the endogenous ethylene concentration due to interference from residual ethylene and memory ethylene. If ripening decisions are made based on the distorted endogenous ethylene concentration, it will cause malfunctions in the ripening process. Specifically: (1) The reversible adsorption layer of ethylene will undergo transient desorption under external disturbance. The released ethylene will only cause the detected ethylene concentration to rise sharply for a short time. This short-term rise in ethylene concentration is not the start signal of the fruit's own ripening process. If the short-term rise in ethylene concentration in the ripening space is mistakenly regarded as caused by the fruit having started to continuously release endogenous ethylene, it will be mistakenly judged as the ripening process has started, and thus the injection of exogenous ethylene will be reduced or even stopped in advance, the ripening cycle will be shortened, and the fruit will be not ripened enough. (2) When the fruit has entered the ripening process, the amount of exogenous ethylene gas injection and the ripening process parameters need to be adjusted in combination with the intensity of the endogenous ethylene released by the fruit. If the concentration rise caused by endogenous ethylene is mistakenly identified as caused by the residual ethylene of the previous batch not dissipating or the desorption of memory ethylene by the reversible adsorption layer of ethylene, the best ripening control time will be delayed, resulting in excessive accumulation of endogenous gas release in the fruit, causing problems such as ripening too fast, soft and rotten flesh, and spoilage. (3) Residual ethylene is the background ethylene that has not been dissipated in the previous operation. It will be superimposed with the newly injected exogenous ethylene, making the actual ethylene concentration in the ripening space higher than the process setting value. This will cause the fruit to be stimulated by excessive ethylene, resulting in uneven ripening, fruit damage, and a significant shortening of shelf life.

[0006] In summary, existing ethylene detection methods fail to identify the true source of ethylene within the ripening space, leading to distortion of the endogenous ethylene concentration, which is the core basis for controlling the ripening process, and ultimately causing malfunctions in the ripening process. Summary of the Invention

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: Firstly, an online ethylene detection system for the ripening environment of post-ripening fruits is proposed, including: The sampling circuit includes: a main air intake, located in the return air main area in the middle of the ripening space; a near-wall air intake, located in the near-wall area of ​​the laminar flow boundary layer near the box wall, the inner wall of the air duct, the liner, and the inner wall of the packaging within the ripening space; a near-fruit pile air intake, located in the near-fruit pile area near the surface of the fruit pile; a sampling assembly, used to sequentially deliver the gas from the main air intake, the near-wall air intake, and the near-fruit pile air intake to the ethylene sensor; and an ethylene sensor, used to collect the ethylene concentration in the gas. The controlled disturbance excitation unit is used to apply positive and negative disturbances to the ripening space. The positive disturbance is used to reduce the thickness of the laminar boundary layer, increase the airflow velocity in the near-wall region, and increase the gas exchange rate between the laminar boundary layer and the return air mainstream region. The negative disturbance is used to restore the gas conditions of the ripening space from the unsteady conditions after the positive disturbance to the baseline conditions. The controller, connected to the sampling component, ethylene sensor, and controlled perturbation excitation unit, includes the following components connected in series: a baseline acquisition module for acquiring the near-wall baseline gradient and near-fruit pile baseline gradient based on the vinyl line concentration at each gas inlet; a first feature extraction module for extracting the peak overshoot and gradient evolution characteristics at each gas inlet based on the ethylene concentration sequence at each gas inlet during forward perturbation; a second feature extraction module for calculating the recovery time constant and hysteresis area at each gas inlet based on the ethylene concentration sequence at each gas inlet during reverse perturbation and recovery; a silent observation and analysis module for obtaining the accumulation slope at each gas inlet based on the ethylene concentration sequence acquired under conditions of no external ethylene injection and unchanged ventilation; and a source decoupling determination module for determining the ethylene source in the ripening space based on the peak overshoot, gradient evolution characteristics, recovery time constant, hysteresis area, and accumulation slope, and outputting the determination result.

[0008] Secondly, a method for online detection of ethylene in the ripening environment of post-ripening fruits is proposed, including the following steps: Gas and ethylene concentration were collected sequentially from the return air mainstream area, near-wall area, and near-fruit pile area of ​​the ripening space to obtain the vinyl line concentration of each area. The near-wall baseline gradient and near-fruit pile baseline gradient were obtained based on the vinyl line concentration of each area. The return air mainstream area is located in the middle of the ripening space, the near-wall area is located in the laminar boundary layer of the ripening space near the box wall, the inner wall of the air duct, the liner, and the inner wall of the packaging, and the near-fruit pile area is near the top of the fruit pile surface. A positive perturbation is applied to the ripening space, and the ethylene concentration sequence of each region is collected during the perturbation process. The peak overshoot and gradient evolution characteristics of each region are extracted. The positive perturbation is used to reduce the thickness of the laminar boundary layer, increase the airflow velocity in the near-wall region, and increase the gas exchange rate between the laminar boundary layer and the return air mainstream region. A reverse perturbation is applied to the ripening space. During the reverse perturbation and recovery process, the ethylene concentration sequence of each region is collected, and the recovery time constant and hysteresis area of ​​each region are calculated. The reverse perturbation is used to restore the gas conditions of the ripening space from the unsteady conditions after the forward perturbation to the baseline conditions. The accumulation slope of each region was obtained based on the ethylene concentration sequence collected under the condition of no external ethylene injection and constant ventilation. Based on the peak overshoot, gradient evolution characteristics, recovery time constant, hysteresis area, and accumulation slope, the source of ethylene in the ripening space is determined, and the determination result is output.

[0009] Thirdly, a computer-readable storage medium is proposed, on which a computer program is stored, which, when executed by a processor, implements an online detection method for ethylene in the ripening environment of post-ripening fruits as described in the second aspect.

[0010] Compared with existing technologies, this invention has the following advantages and beneficial effects: By setting up mainstream gas sampling positions, near-wall gas sampling positions, and near-fruit pile gas sampling positions in the ripening space, multi-location ethylene concentration time series are obtained. A non-steady-state detection process is constructed by combining positive and negative perturbations, actively amplifying the ethylene distribution characteristics that were originally in a steady-state or weakly differentiated state. Based on this, by extracting multiple dynamic response characteristic parameters such as peak overshoot, hysteresis area, recovery time, concentration change slope, and spatial gradient from the concentration time series, and combining these with background quantities such as mainstream average concentration, the differences in ethylene from different sources in the three dimensions of "perturbation response, recovery process, and spatial distribution" are quantitatively characterized. Furthermore, by comparing the characteristic parameters with a threshold system obtained based on single-source calibration, statistical analysis, and historical data correction, the differences between different ethylene sources, such as wall memory release, endogenous fruit gas release, and uniform residue, can be distinguished. Therefore, compared with existing methods that rely solely on single-point concentration or steady-state measurement, this invention can effectively overcome the identification difficulties caused by the uniformity of ethylene distribution in the ripening space, improve the ability to distinguish and judge ethylene from different sources, and through multi-parameter collaborative judgment and threshold normalization processing, the detection results have better stability and applicability in ripening equipment with different volumes, different ventilation conditions and different loading states, thereby improving the controllability of the ripening process and the reliability of data. Attached Figure Description

[0011] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of an online ethylene detection system for ripening post-ripening fruits provided in Embodiment 1 of the present invention.

[0012] The attached diagram shows the markings and corresponding component names: 1-Temperature sensor; 2-Humidity sensor; 3-Wind speed sensor; 4-Differential pressure sensor; 5-Main air intake; 6-Near-wall air intake; 7-Near-fruit pile air intake; 8-Ventilation assembly; 9-T-way; 10-Condensate trap; 11-Particulate filter; 12-Flow stabilizer; 13-Auxiliary calibration branch; 14-Ethylene sensor; 15-Pulse suction assembly; 16-Sampling pump; 17-Multi-way switching valve; 18-Ethylene removal module; 19-Circulating fan speed control assembly; 20-Local boundary layer disturbance jet assembly. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The illustrative embodiments and descriptions of this invention are for illustrative purposes only and are not intended to limit the invention. The embodiments described below are some, but not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0014] In the following description, numerous specific details are set forth to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, materials, or methods are not specifically described to avoid obscuring the invention. Unless otherwise specified, the materials, instruments, and reagents used in the following embodiments are commercially available. Unless otherwise specified, the techniques used in the embodiments are conventional methods well known to those skilled in the art.

[0015] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0016] Example 1: To identify the true source of ethylene in the ripening space and avoid misoperation of the ripening process due to the distortion of the detected endogenous ethylene concentration, this example provides an online ethylene detection system for the ripening environment of post-ripening fruits. By analyzing the differentiated characteristics of residual ethylene, memory ethylene and endogenous ethylene in three dimensions—spatial distribution, dynamic response and steady-state release—online decoupling and quantitative characterization of different sources of ethylene in the ripening environment can be achieved. Specifically, firstly, based on the differences in physical sensitivity among the mainstream region, near-wall region, and near-fruit pile region, gas sampling points are simultaneously set in these regions to spatially distinguish ethylene sources. Then, through forward perturbation and its corresponding reverse perturbation, the differences in peak overshoot, recovery rate, hysteresis behavior, and gradient evolution among different ethylene sources are actively amplified. Next, a silent observation window is used to verify whether each ethylene source has a continuous release trend. Finally, based on the baseline gradient, peak overshoot, recovery time constant, hysteresis area, and accumulation slope of each sampling point, the ethylene source is decoupled and determined, thus forming a complete technical route of "multi-location baseline acquisition - forward perturbation - reverse perturbation and recovery - silent observation - source decoupling determination - environmental monitoring fingerprint recording".

[0017] The mainstream area refers to the region within the ripening space where gas exchange is sufficient and which can represent the overall mixed atmosphere. It is located in the middle of the ripening space and close to the return air circulation mainstream line.

[0018] The near-wall region refers to the boundary layer region close to the box wall, liner, inner wall of the packaging, inner wall of the air duct, and inner wall of the sampling pipeline. This region is sensitive to the adsorption-desorption process of ethylene.

[0019] The area near the fruit pile refers to the region above the surface of the fruit pile, which is sensitive to the endogenous ethylene release process of the fruit population.

[0020] Positive disturbance refers to a disturbance process that, according to a pre-set disturbance type, amplitude, duration, and execution sequence, reduces the thickness of the local boundary layer, increases the local flow velocity, and improves the degree of ventilation in the ripening space.

[0021] Reverse disturbance refers to the process of restoring the working condition for the same disturbance object in the opposite direction or the direction of retreat.

[0022] Peak overshoot refers to the dynamic response phenomenon in which, after a positive disturbance is applied, the ethylene concentration at a certain gas intake port rises rapidly relative to the corresponding vinyl line concentration, and a local maximum value appears.

[0023] Recovery rate refers to how quickly the ethylene concentration at a certain gas intake point falls back from the peak of the disturbance to near the steady-state baseline after the start of the reverse disturbance. It can be characterized by the recovery time constant or the amount of concentration decrease per unit time.

[0024] Hysteresis behavior refers to the phenomenon that the ethylene concentration at the same gas intake does not completely overlap with the rising and falling paths during positive and negative disturbances, resulting in a delayed response.

[0025] Gradient evolution refers to the process by which the difference in ethylene concentration between the near-wall region or near-fruit pile region and the mainstream region changes over time during positive disturbance and recovery.

[0026] The baseline gradient refers to the difference between the vinyl line concentration in the near-wall region or near-fruit pile region and the vinyl line concentration in the mainstream region under undisturbed steady state, and is used to characterize the initial spatial distribution differences.

[0027] Peak overshoot refers to the maximum increment of the peak ethylene concentration at any point during the disturbance phase relative to the corresponding vinyl line concentration.

[0028] The recovery time constant refers to the time difference between the peak ethylene concentration and the corresponding vinyl line concentration at a given gas sampling point after a reverse disturbance is applied, following the return of the ethylene concentration from its peak. e -1 The time required.

[0029] Hysteresis area refers to the integral area of ​​the relative vinyl line concentration increment curve at the same location within a specified calculation window during the positive disturbance and recovery phases.

[0030] The cumulative slope refers to the slope obtained by performing a univariate linear regression with time as the independent variable and ethylene concentration as the dependent variable within a silent observation window.

[0031] Based on the above technical approach, this embodiment describes an online ethylene detection system for the ripening environment of post-ripening fruits, including as follows: Figure 1 The sampling loop, controlled disturbance excitation unit, controller, and environmental parameter acquisition unit are shown.

[0032] 1. Sampling circuit Since single-point sampling alone cannot capture the spatial distribution differences of different ethylene source terms, and multi-sensor multi-channel sampling has systematic errors such as zero-point drift, this embodiment sets up a sampling loop including a main gas intake 5, a near-wall gas intake 6, a near-fruit pile gas intake 7, a sampling component, and an ethylene sensor 14. This enables multi-location differentiated gas intake and single-sensor polling measurement in the ripening space. It establishes a sensitive correspondence between different ethylene source terms and sampling locations through differentiated gas intakes, and eliminates the systematic errors of multiple sensors through polling measurement with the same sensor. This ensures the comparability of detection data at different locations and provides a data foundation for subsequent source term decoupling.

[0033] (1) Mainstream air intake port 5 To obtain a baseline concentration of the mixed gas representative of the entire ripening space and provide a unified reference for subsequent ethylene concentration gradient calculation and characteristic comparison, the mainstream air intake 5 described in this embodiment is located in the return air mainstream area in the middle of the ripening space. This return air mainstream area has sufficient gas exchange and a stable flow field, and the distance from this area to the top or bottom of the chamber is 0.4 to 0.6 times the total height of the chamber. The return air mainstream area is the region with the most uniform gas mixing and minimal interference from the air supply jet, return air suction, and door leakage. Simultaneously, the straight-line distance between the mainstream air intake 5 and the air supply port and external ethylene injection port should be greater than or equal to 500 mm to avoid interference from localized gas injection or exchange on the collected ethylene linear concentration. In a preferred embodiment, the mainstream air intake 5 can be made of 304 stainless steel, with an aperture of 8 mm; a 1 mm aperture stainless steel mesh can be installed at the front end of the mainstream air intake 5 to intercept fruit debris and dust.

[0034] (2) Near-wall air intake 6 Unlike residual ethylene that is not completely discharged after previous batches of processing and forms a uniformly dispersed distribution within the ripening space, ethylene released from the box walls, duct inner walls, liners, packaging materials, and turnover basket surfaces first accumulates in the laminar boundary layer near the wall surface, forming a reversible ethylene adsorption layer. Under external disturbances, this reversible ethylene adsorption layer rapidly desorbs and releases ethylene, and after the disturbance ends, the reversible ethylene adsorption layer quickly recovers. In this embodiment, the ethylene released from the box walls, duct inner walls, liners, packaging materials, and turnover basket surfaces is referred to as adsorption-desorption type ethylene. To capture the adsorption-desorption characteristics and maximize the detection sensitivity for adsorption-desorption type ethylene, the near-wall air intake 6 described in this embodiment is located in the area where the laminar boundary layer is located near the box walls, duct inner walls, liners, and packaging inner walls of the ripening space. Flow field simulation and field measurements have verified that the typical thickness range of the laminar boundary layer near the wall surface within the ripening space is 20mm to 80mm. In areas greater than 80mm from the wall, adsorbed-desorbed ethylene is diluted by the mainstream. If the distance between the near-wall air intake 6 and the wall is greater than 80mm, the transient peak value of adsorbed-desorbed ethylene released by the reversible adsorption layer under external disturbance cannot be captured. If the distance between the near-wall air intake 6 and the wall is less than 20mm, it is easily blocked by debris on the wall, and the airflow stability is poor. Therefore, in this embodiment, the near-wall air intake 6 is preferably set in an area of ​​20mm to 80mm from the wall. In a preferred embodiment, the near-wall air intake 6 can be made of 304 stainless steel, and the aperture can be selected as 6mm. Two 1mm aperture stainless steel mesh covers can be installed at the front end of the near-wall air intake 6. One stainless steel mesh cover is arranged near the inner wall of the return air duct, and the other stainless steel mesh cover is arranged near the liner of the box wall. In addition, the distance between the near-wall air intake 6 and the wall can be set to 50mm.

[0035] (3) Gas intake port 7 near the fruit pile Unlike ethylene released from the walls of the container, the inner walls of the air duct, the lining, the packaging materials, and the surface of the turnover basket, which accumulates in the laminar boundary layer near the wall surface, ethylene released from the fruit first accumulates in the stagnant layer above the fruit pile surface. To capture changes in the concentration of ethylene released from the fruit as quickly as possible and maximize the detection sensitivity, the near-pile air intake 7 described in this embodiment is located in the near-pile area, close to the stagnant layer above the fruit pile surface. To prevent the ethylene released from the fruit from losing its source specificity due to dilution by the mainstream gas, the near-pile air intake 7 is preferably located 20mm to 120mm above the fruit pile surface. In a preferred embodiment, the near-pile air intake 7 can be made of 304 stainless steel, with a 6mm aperture; a 1mm aperture stainless steel mesh cover can be installed at the front end of the near-pile air intake 7.

[0036] (4) Sampling component To achieve polling sampling of the main gas intake 5, near-wall gas intake 6, and near-fruit pile gas intake 7, and to ensure the comparability of the detection data, this embodiment uses a sampling component to sequentially introduce the gas from the main gas intake 5, near-wall gas intake 6, and near-fruit pile gas intake 7 into the same ethylene sensor 14 for measurement according to a preset time sequence. The sampling component consists of a multi-way switching valve 17, a sampling pump 16, and sampling pipelines. The multi-way switching valve 17 is preferably a 3-position 3-way PTFE sealed solenoid valve with a switching dead volume of less than 50 μL and a response time of less than 100 ms, enabling rapid switching between the main gas intake 5, near-wall gas intake 6, and near-fruit pile gas intake 7 under the control of a controller. By polling and monitoring the gas at the three intakes using the same ethylene sensor 14, systematic errors caused by zero-point drift, sensitivity differences, and inconsistent temperature drift characteristics during parallel detection by multiple sensors can be eliminated, ensuring the comparability of the gas detection data at the three intakes and providing a data basis for source term decoupling. Sampling pump 16 is a miniature diaphragm pump with an output flow rate of 0.2L / min to 1.0L / min. It features stable flow, low noise, and resistance to high humidity. The flow rate can be adjusted in stages via a controller, providing stable gas driving power for the sampling circuit. The main gas intake 5, near-wall gas intake 6, and near-fruit pile gas intake 7 are all connected to the multi-way switching valve 17 via high-purity polytetrafluoroethylene (PTFE) tubing with an inner diameter of 4mm to 6mm, after being combined via a tee 9. The inner wall of the tubing is polished to minimize the physical adsorption of ethylene molecules, avoiding adsorption lag and data distortion during low-concentration detection. The tubing connectors use stainless steel double-ferrule fittings to ensure airtightness and prevent concentration detection deviations caused by leaks.

[0037] (5) Ethylene sensor 14 In order to accurately quantify the ethylene concentration in the sampled gas, this embodiment is equipped with an ethylene sensor 14, which can be a ppm-level non-dispersive infrared (NDIR) ethylene sensor 14 or a high-performance electrochemical ethylene sensor 14. The preferred measurement range is 0ppm to 50ppm, the resolution is no greater than 0.01ppm, and the response time is no greater than 30s.

[0038] 2. Controlled disturbance excitation unit In existing technologies, static multi-point gradient sampling can identify differences in ethylene concentration within the ripening space under steady-state conditions. However, for dynamically released ethylene, such as ethylene released through wall adsorption-desorption and ethylene continuously released from the fruit, the sensitivity of static multi-point gradient sampling is insufficient, failing to effectively amplify the essential differences between different ethylene source terms. Therefore, this embodiment employs a controlled perturbation excitation unit that actively disrupts the steady-state flow field through paired positive and negative perturbations, stimulating dynamic response differences among different ethylene source terms. This transforms source term characteristics, which were previously difficult to identify under static conditions, into quantifiable, extractable, and decoupling-compatible inspection parameters.

[0039] The controlled disturbance excitation unit is used to apply repeatable and standardized positive disturbances and completely corresponding negative disturbances to the ripening space according to a preset disturbance program. Through paired excitation-recovery processes, it actively amplifies the response differences of different ethylene source terms in the time and spatial domains. Preferably, the preset disturbance program includes at least five parameters: disturbance type, disturbance amplitude, disturbance duration, execution order, and recovery judgment condition. In the same batch of testing, it is preferable to keep the five parameters consistent to ensure comparability between different testing rounds. The controlled disturbance excitation unit includes a circulating fan speed change assembly 19, a pulse suction assembly 15, a local boundary layer disturbance jet assembly 20, and a ventilation assembly 8, which can be configured according to the type and volume of the ripening space.

[0040] (1) Circulating fan speed change assembly 19 The circulating fan speed control assembly 19 is used to controllably disturb the flow field of the laminar boundary layer by step changes in fan speed. Its core working logic is as follows: Forward disturbance stage - the fan is stepped up from the first operating condition v1 to the second operating condition v2, causing the laminar boundary layer near the wall to rapidly thin or collapse. Specifically, through the step change in fan speed, the laminar boundary layer with low flow velocity and poor gas exchange near the wall is broken by the high-speed airflow, which promotes the desorption of ethylene adsorbed on the wall and its entry into the gas phase; Reverse disturbance stage - the fan is stepped back from the second operating condition v2 to the first operating condition v1, so that the flow field of the ripening space gradually returns to a steady state, while the change characteristics of ethylene concentration during the reconstruction of the laminar boundary layer are obtained.

[0041] In a preferred embodiment, the fan speed increase in the second operating condition v2 relative to the first operating condition v1 is preferably 10% to 60%. If the fan speed increase is less than 10%, it is difficult to achieve effective collapse of the laminar boundary layer, and the disturbance effect cannot be achieved. If the fan speed increase is greater than 60%, it will cause violent disturbance of the airflow in the entire ripening space, thereby eliminating the spatial distribution differences of different source terms and making it impossible to distinguish source terms. At the same time, the step change time of the fan speed can be set within 1s to 5s to avoid the slow increase of the fan speed failing to cause transient desorption of the laminar boundary layer, thus failing to obtain the peak characteristics of ethylene concentration. For example, the original variable frequency circulating fan in the ripening chamber can be set to 40% of its rated speed under steady-state operating condition v1 and 60% of its rated speed under positive disturbance condition v2, with a speed increase of 50%. The fan speed increase time can be set to within 2 seconds, and the positive disturbance duration is 8 seconds. Under reverse disturbance, the fan speed is reduced back to 40% of its rated speed within 2 seconds, thus entering the recovery phase of the laminar boundary layer. By controlling the fan speed to undergo sequential positive and reverse step changes, rapid collapse and reconstruction of the laminar boundary layer can be achieved, thereby effectively stimulating the desorption and re-adsorption of ethylene adsorbed on the wall and amplifying the corresponding response characteristics.

[0042] (2) Pulse suction assembly 15 The pulse suction assembly 15 is installed on the sampling pipeline. It is used to apply additional strong suction to the laminar boundary layer while the circulating fan speed-changing assembly 19 provides controllable disturbance to the laminar boundary layer, thereby amplifying the local ethylene concentration characteristics in the near-wall and near-pile regions. The pulse suction assembly 15 can be a pulse negative pressure assembly consisting of a high-speed solenoid valve, a buffer chamber, a throttling device, and a suction pump, or an adjustable pulse suction assembly 15 consisting of a proportional valve and a vacuum generator. Its pulse duration is preferably 2s to 15s, and the instantaneous suction flow rate is preferably 1.5 to 4 times the steady-state sampling flow rate.

[0043] (3) Local boundary layer disturbance jet assembly 20 The local boundary layer disturbance jet assembly 20 is positioned near the wall surface. While the circulating fan speed-changing assembly 19 provides controllable disturbance to the laminar boundary layer, it simultaneously applies an additional short-duration directional jet to scour the laminar boundary layer, thereby actively stimulating ethylene desorption. The jet direction is preferably at an angle of 10° to 45° to the wall surface. If the angle is less than 10°, the jet can only scour the surface layer of the wall and cannot disrupt the original state of the laminar boundary layer; if the angle is greater than 45°, the jet will directly impact the wall surface, forming vortices, causing the desorbed ethylene to diffuse throughout the entire ripening space, losing its local characteristics. Furthermore, the jet medium can be the circulating gas within the ripening space, avoiding concentration dilution interference caused by the introduction of fresh air. The local boundary layer disturbance jet assembly 20 can be a directional jet assembly consisting of a nozzle, an air supply branch, a solenoid valve, a pressure stabilizing chamber, and a flow regulating valve, or a jet assembly that forms a local parallel jet by a micro fan in conjunction with a slit nozzle; the jet duration is preferably 1s to 8s, and the jet outlet linear velocity is preferably 0.5m / s to 5m / s.

[0044] (4) Ventilation assembly 8 The ventilation component 8 is used to introduce a small amount of fresh air by briefly opening the ventilation valve, so as to generate repeatable small-amplitude ventilation events in the ripening space. By instantaneously changing the ethylene concentration field in the ripening space, the response differences of different ethylene source items are amplified.

[0045] 3. Controller The sampling loop provides ethylene concentration data in the spatial dimension, while the controlled perturbation excitation unit amplifies the dynamic response differences of different ethylene source terms in the temporal dimension. Based on this, this embodiment uses a controller to transform the ethylene concentration data and the dynamic responses of different ethylene source terms into actionable ethylene source term determination results.

[0046] The controller is electrically connected to the sampling loop, the controlled disturbance excitation unit, and the environmental parameter acquisition unit, respectively, and controls the sampling loop, the controlled disturbance excitation unit, and the environmental parameter acquisition unit to collaboratively complete the entire process scheduling, including the "static baseline acquisition stage, forward disturbance stage, reverse disturbance and recovery stage, silent observation stage, and source decoupling determination stage." Correspondingly, the controller includes: a baseline acquisition module, a forward disturbance feature extraction module, a recovery feature extraction module, a silent observation analysis module, and a source decoupling determination module, used to execute the above five stages respectively.

[0047] (1) Baseline acquisition module During the static baseline acquisition phase, the baseline acquisition module controls the multi-way switching valve 17 to sequentially switch the main gas intake 5, the near-wall gas intake 6, and the near-fruit pile gas intake 7 to obtain the main vinyl line concentration under undisturbed steady state. Near-wall vinyl line concentration and near-fruit pile vinyl line concentration The initial spatial gradient is calculated to provide a unified benchmark for all subsequent dynamic feature calculations. In this stage, the baseline acquisition module controls the multi-way switching valve 17 to sequentially connect the main gas intake 5, the near-wall gas intake 6, and the near-fruit pile gas intake 7. After each switch, a purging operation is performed to completely empty the residual gas in the pipeline, preventing interference from residual gas collected at the previous intake. The purging operation time can be controlled between 5s and 12s. After the ethylene concentration enters the stable range, the median of the continuous sampling data in the stable range is taken as the vinyl line concentration value of ethylene at the current intake. In this embodiment, the ethylene concentration entering the stable range means that the relative standard deviation (RSD) of the ethylene concentration is less than 3% for 10 consecutive seconds, and the absolute value of the first-order difference between adjacent sampling points is continuously lower than 0.02ppm / s. Finally, based on the main vinyl line concentration... Near-wall vinyl line concentration and near-fruit pile vinyl line concentration The near-wall baseline gradient was calculated. and near-baseline gradient Baseline acquisition was completed. , .

[0048] (2) First feature extraction module After baseline acquisition is completed, the forward perturbation phase begins. During this phase, the forward perturbation feature extraction module controls the controlled perturbation excitation unit to perform forward perturbation, continuously acquiring the ethylene concentration sequence at the main gas intake 5 at a sampling frequency of no less than 1 Hz during the perturbation process. Ethylene concentration sequence at near-wall gas intake 6 Ethylene concentration sequence at near-fruit pile gas outlet 7 ;based on , and Extract peak overshoot and gradient evolution features. Peak overshoot includes: mainstream peak overshoot. Near-wall peak overshoot and peak overshoot of near-fruit pile These values ​​represent the sensitivity of the corresponding gas intake location to positive disturbances. A larger value indicates a stronger response of the ethylene source term at that location to the positive disturbance. Furthermore, , , t1 represents the start time of the positive perturbation, and t2 represents the end time of the positive perturbation. The gradient evolution characteristics are illustrated by the near-wall gradient evolution curve. Its peak value, mean, zero-crossing time, and monotonicity, as well as the near-heap gradient evolution curve. It is represented by its peak value, mean, zero-crossing time, and monotonicity; furthermore, , .

[0049] (3) Second feature extraction module After the forward perturbation phase ends, the reverse perturbation and recovery phase begins. The purpose is to perform a rollback based on the forward perturbation, obtaining the recovery characteristics of different ethylene source terms during the laminar boundary layer reconstruction process. This further distinguishes between ethylene released by transient desorption in the laminar boundary layer and ethylene continuously released from the fruit, providing a basis for ethylene source term determination. In the reverse perturbation and recovery phase, the recovery feature extraction module controls the controlled perturbation excitation unit to execute the reverse perturbation corresponding to the forward perturbation, continuously acquiring the ethylene concentration sequence at the main gas intake 5. Ethylene concentration sequence at near-wall gas intake 6 Ethylene concentration sequence at near-fruit pile gas outlet 7 And a first-order exponential decay model was used to analyze the ethylene concentration sequence. ethylene concentration sequence and ethylene concentration sequence The recovery time constant at the main air intake 5 was obtained by fitting the data. Recovery time constant at 6 near-wall gas intake points The recovery time constant at point 7 of the near-fruit pile gas intake. Simultaneously, within a preset time window, trapezoidal integrals were performed on the relative vinyl line concentration increments at the main intake 5, the near-wall intake 6, and the near-pile intake 7, respectively, to obtain the main hysteresis area. Near-wall hysteresis area and the area of ​​near-fruit pile lag .

[0050] The recovery time constant refers to the difference between the peak ethylene concentration and the vinyl line concentration at each gas intake after the reverse disturbance is applied, as the ethylene concentration drops from its peak value. e -1 The required recovery time constant is used to characterize the sustained characteristics of the ethylene release source. A smaller recovery time constant indicates that the ethylene release at each intake point is closer to the transient, perturbed desorption characteristic; a larger recovery time constant indicates that the ethylene release at each intake point is closer to the sustained, endogenous release characteristic. The recovery time constant is obtained by fitting a first-order exponential decay model, the fitting model being: ; i Indicates the air intake point. , m This indicates there are 5 main air intakes. w This indicates 6 air intake points near the wall. This indicates 7 gas intake points near the fruit pile; t Indicates time; This indicates that after the reverse disturbance is applied, the air intake... i exist t Ethylene concentration at any given time, in ppm; Indicates air intake port i Vinyl concentration, in ppm; When the positive disturbance ends, the gas intake port i The peak ethylene concentration, in ppm; The time of initiation of the reverse disturbance is expressed in seconds. For air intake i The recovery time constant.

[0051] The hysteresis area is used to characterize the total amount of ethylene released at each gas intake during the disturbance. To avoid calculation ambiguity caused by the incomplete overlap of the peak ethylene concentration times at different gas intakes, in this embodiment, the hysteresis area is defined as the area obtained by performing a trapezoidal integral on the relative vinyl line concentration increment from the start time t1 of the positive disturbance to the end time te of the recovery. The formula for calculating the relative vinyl line concentration increment is: ;in, Indicates air intake port i exist t The relative baseline increment at each time point. Based on the relative vinyl line concentration increment at each gas intake, the cumulative value Hi of the relative vinyl line concentration increment at each gas intake from the start time t1 of the positive disturbance to the end time te of the recovery is calculated. This value reflects the total cumulative increase in ethylene concentration relative to the baseline over a period of time, and can quantify the overall intensity of ethylene release. (Cumulative value of relative vinyl line concentration increment) H i The calculation formula is: .

[0052] In this embodiment, the preferred end condition for the recovery phase is that the absolute values ​​of the fluctuation amplitudes of the ethylene concentrations at the main gas inlet 5, the near-wall gas inlet 6, and the near-fruit pile gas inlet 7 within 10 consecutive seconds are all less than 0.03 ppm, and the differences between these concentrations and the ethylene concentration line are all less than 0.05 ppm.

[0053] (4) Silent Observation and Analysis Module After the recovery phase, the silent observation phase begins. During this phase, the silent observation analysis module continuously collects ethylene concentration data for a preset duration under steady-state conditions with no external ethylene injection, constant ventilation, and no disturbance. It calculates the accumulation slope at each gas intake point. The purpose is to verify the continuous release characteristics of different ethylene sources after completely eliminating external interference, distinguishing between transient releases caused by external disturbances and continuous releases caused by fruit physiological activities, thus avoiding misjudgments. The optimal silent observation window duration for this phase is 3 to 20 minutes, which can be flexibly adjusted according to the ethylene release characteristics of different fruit varieties. To improve the stability of the slope calculation, the silent observation window can be divided into multiple sub-windows. A univariate linear regression is used to calculate the corresponding slope for the ethylene concentration sequence within each sub-window, and the median value of the corresponding slope for each sub-window is taken as the accumulation slope. The accumulation slope at the main gas intake point 5 is shown below. S m Accumulated slope at 6 near-wall air intake points S w and the cumulative slope at point 7 near the gas intake of the fruit pile S f They can be represented as: , , ,in, t j For the first silent observation window j Each sampling time, N The total number of sampling points. This is the average value at each sampling time. This represents the average value of the ethylene concentration sequence corresponding to the main gas intake. This represents the average value of the ethylene concentration sequence corresponding to the near-wall gas intake. This represents the average ethylene concentration sequence corresponding to the gas extraction port near the fruit pile, and , , , .

[0054] (5) Source decoupling determination module After completing the feature acquisition in the previous four stages, the process proceeds to the ethylene source decoupling determination stage. The source decoupling determination module integrates the feature parameters extracted from each of the preceding stages (including the mainstream vinyl line concentration). Near-wall vinyl line concentration Near-fruit pile vinyl line concentration Near-wall baseline gradient Near-field baseline gradient Mainstream peak overshoot Near-wall peak overshoot Near-peak overshoot Near-wall gradient evolution curve Gradient evolution curve of near-fruit pile Recovery time constant , , Hysteresis area , , Silent observation accumulated slope , , Near-wall gradient average within the silent observation window Near-heap gradient average and mainstream average concentration By combining the essential differences in the three types of ethylene source terms, the decoupling determination of ethylene sources is completed. Furthermore, , , The specific judgment logic is as follows: Determination of memory ethylene release from the reversible ethylene adsorption layer under external stimuli such as airflow disturbance: when the near-wall peak overshoot... Compared with mainstream peak overshoot The difference between them (i.e.) The hysteresis area at the near-wall air intake 6 reaches the first near-wall judgment threshold T1. The second near-wall determination threshold T2 is reached, and the recovery time constant at the near-fruit pile gas inlet 7 is... Recovery time constant at near-wall gas intake 6 The difference between them (i.e.) When the recovery time difference threshold T3 is reached, it is determined that memory ethylene exists in the ripening space. The physical basis of this judgment logic is: ethylene adsorbed on the wall desorbs rapidly under positive perturbation, and a significant peak overshoot appears in the near-wall region; after the perturbation is removed, there is no continuous ethylene replenishment, and the near-wall position recovers faster.

[0055] Determination of endogenous ethylene release from fruit: The accumulation slope at 7 gas intake points near the fruit pile during the silent observation phase. S f The accumulated slope at the main gas intake point 5 during the silent observation phase S m The difference between them (i.e.) The release slope threshold T4 is reached, as well as the recovery time constant at the near-pile gas inlet. Subtract the recovery time constant at the main air intake point 5 Recovery time constant at near-wall gas intake port 6 The larger of the two values ​​(i.e.) When the recovery hysteresis threshold T5 is reached, it is determined that there is endogenous ethylene continuously released from the fruit. The physical basis for this judgment logic is that the endogenous gas release from the fruit is a continuous physiological process that is not significantly affected by disturbances. Therefore, the concentration drops slowly after the disturbance is removed, and the recovery time constant is large. In the undisturbed quiescent phase, the concentration in the area near the fruit pile continues to rise, and the accumulation slope is significantly higher than that in the mainstream area.

[0056] Determination of uniformly diffuse residual ethylene: when the absolute value of the mean near-wall baseline gradient within the silent observation window... The absolute value of the mean gradient of the near-row base plate At the same time, it is below the spatial gradient threshold T6, and the average ethylene concentration in the mainstream region When the concentration exceeds the background threshold T7, residual ethylene is determined to be present. The physical basis for this determination logic is that residual ethylene is uniformly dispersed throughout the space with no obvious local concentration differences, so the baseline gradient values ​​at each gas intake location are extremely low; at the same time, the overall background concentration in the space is high, with no obvious local release characteristics.

[0057] When at least two types of ethylene source items simultaneously meet the corresponding judgment conditions, the source decoupling judgment module outputs the mixed ethylene source judgment result.

[0058] Furthermore, in order to quantitatively characterize the intensity of ethylene source terms and determine the contribution ranking of each ethylene source term under mixed ethylene sources, the source decoupling determination module can construct wall memory release intensity indices based on the extracted feature parameters and a normalized weighted algorithm. Fruit endogenous gas release intensity index Uniform residual strength index Furthermore, the wall memory release intensity index The calculation formula is: Fruit endogenous gas release intensity index The formula for calculation is: Uniform residual strength index The calculation formula is: .in, ε It is a very small positive number, and can take the following values: This is used to avoid the denominator being 0; The reference hysteresis area can be calibrated through a pure wall release test under standard operating conditions; This is the reference background concentration under uniform residual conditions; This represents the average near-wall gradient within the silent observation window; The average gradient of the near-fruit pile; The mainstream average concentration within the silent observation window; All are weighted coefficients, which can be calibrated offline through orthogonal experiments on a standard prototype under known single ethylene source conditions, or obtained through regression of historical valid operating data, and the coefficients of each group preferably satisfy the condition that the sum of the coefficients in the same group is 1.

[0059] Preferably, the thresholds T1 to T7 can be determined according to the process of "single source calibration, statistical analysis, historical correction, and normalization conversion". Specifically, for the same fruit variety, the same packaging form, and the same type of ripening space, single wall memory release condition, single fruit endogenous gas release condition, and single uniform residue condition are established respectively. Calibration experiments are repeated under each condition to extract key characteristic parameters such as the difference between the near-wall peak overshoot and the mainstream peak overshoot, the near-wall hysteresis area, the difference between the near-fruit pile and the near-wall recovery time constant, the difference between the near-fruit pile and the mainstream accumulation slope, the recovery hysteresis of the near-fruit pile relative to the mainstream or near-wall, the average absolute gradient between the near-wall and the near-fruit pile, and the average concentration of the mainstream. When determining each threshold, the calibration condition consistent with the ethylene source corresponding to that threshold is defined as the target calibration condition, and the calibration conditions of other ethylene sources are defined as comparison conditions. The mean, standard deviation, and 95th percentile of each key characteristic parameter are statistically analyzed. For judgment thresholds such as T1 to T5, which increase with the enhancement of the corresponding ethylene source characteristics, the judgment threshold can be selected between the distribution ranges of the two types of parameters by combining the mean value of the characteristic parameters under the target calibration condition and the 95th percentile value of the characteristic parameters under the comparison condition. This ensures that when the measured value of the characteristic parameter reaches or exceeds the threshold, the corresponding ethylene source characteristic is considered to have reached a level of identifiability. The initial threshold can be set as the median value of the 95th percentile values ​​of the two types of conditions. For example, the peak overshoot difference threshold T1 corresponding to wall memory release can be set to 0.20 ppm, the near-wall hysteresis area threshold T2 can be set to 0.50 ppm, the recovery time difference threshold T3 can be set to 5 s, the cumulative slope difference threshold T4 corresponding to fruit endogenous gas release can be set to 0.02 ppm / min, and the recovery hysteresis threshold T5 can be set to 4 s. For threshold types like T6, which are used to determine the uniformity of spatial concentration, the 95th percentile of the average absolute values ​​of the near-wall concentration gradient and the near-fruit pile concentration gradient under a single uniform residue condition can be used. For example, 0.05 ppm can be used as the spatial gradient threshold. When both the near-wall gradient and the near-fruit pile gradient are not higher than this threshold, the concentration distribution at each location within the ripening space is considered to be relatively uniform. For threshold types like T7, which are used to limit the background residue concentration, the threshold can be determined by combining the mean and standard deviation of the mainstream average concentration under a single uniform residue condition. For example, the mean of the mainstream average concentration minus twice the standard deviation can be used as the background concentration threshold, preferably 0.50 ppm. When the mainstream average concentration reaches or exceeds this threshold, identifiable background residual ethylene is considered to exist within the ripening space. Based on this, the above thresholds can be further revised using historical valid operating data to improve the consistency of judgments across batches and multiple operating conditions. For ripening spaces with large volume differences, the threshold can be normalized by combining the volume of the ripening space, the rated air volume of the fan, and the fruit pile loading rate, so that the same set of judgment rules can be adapted to ripening equipment of different scales and different flow field conditions.

[0060] (6) Environmental monitoring fingerprint and historical update module To ensure the reliability of the ethylene source term decoupling results and avoid misjudgments caused by hardware anomalies and environmental fluctuations, while also achieving cross-batch operating condition adaptation and self-optimization, the controller also includes an environmental detection fingerprint and historical update module, which is used to perform environmental detection fingerprint recording and adaptive updating of historical parameters.

[0061] Environmental monitoring fingerprint recording refers to the structured recording of all data from the entire monitoring process into standardized environmental monitoring fingerprints, stored locally or uploaded to a host computer, enabling full traceability of monitoring results. The environmental monitoring fingerprints adopt a standardized JSON format or structured database record format, and include at least nine categories of fields: basic monitoring information, baseline acquisition data, disturbance response characteristic data, silent observation data, environmental parameter data, judgment result data, operational suggestion data, and anomaly information. The basic monitoring information includes at least the monitoring date, batch number, fruit variety number, packaging form, ripening space number, and disturbance program number.

[0062] Based on environmental detection fingerprints, an exponentially weighted moving average algorithm is used to analyze the historical wall memory release level. Historical levels of gas release from fruits and historical uniform residual level Cross-batch updates are performed to adaptively adjust the detection threshold and perturbation program for the next batch, improving consistency across batch operations. The historical parameter update formula is as follows: ; ; ; in, k This is the current batch number; k -1 represents the previous batch number; α The value of the smoothing coefficient is preferably between 0.1 and 0.3, and can be adjusted according to the fruit variety and working conditions. This refers to the wall memory release intensity index for the current batch. This is an indicator of the endogenous gas release intensity of the current batch of fruit. The uniform residual strength index for the current batch; the initial value of the historical wall memory release level at the time of the first test. Initial values ​​of historical fruit gas release levels and the initial value of historical uniform residual level It was obtained through standard operating condition calibration in similar ripening spaces.

[0063] 4. Environmental parameter acquisition unit and auxiliary ligand components To ensure the stable operation of the system and reduce the interference of environmental changes and hardware fluctuations on the determination results of ethylene source items, this system is also equipped with an environmental parameter acquisition unit, as well as auxiliary components such as a particulate filter 11, a sampling pump 16, a flow stabilizer 12, a condensate collector 10, and an auxiliary calibration branch 13.

[0064] (1) Environmental parameter acquisition unit The environmental parameter acquisition unit includes a temperature sensor 1, a humidity sensor 2, a wind speed sensor 3, and a differential pressure sensor 4, used to record temperature, humidity, wind speed, and differential pressure information in real time throughout the entire detection process. Temperature sensor 1 and humidity sensor 2 are both located in the main flow area, near the wall, and near the fruit pile within the ripening space; wind speed sensor 3 is located in the main airflow area downstream of the fan outlet within the ripening space; the high-pressure end of differential pressure sensor 4 is located inside the ripening space, and the low-pressure end is located in the external atmospheric environment.

[0065] Correspondingly, the controller also includes an environmental adaptive adjustment module, which dynamically adjusts the disturbance amplitude, sampling frequency, venting time, and observation window duration according to environmental parameters to reduce the interference of environmental changes on the determination of ethylene source terms. For example, when the relative humidity is detected to be continuously higher than 95%RH, the venting time is automatically extended from 5s-20s to 20s-40s, and the sampling frequency is appropriately reduced to reduce transient noise caused by condensation; when the wind speed in the near-wall area is detected to be more than 20% lower than the calibrated wind speed, the duration of positive disturbance is appropriately extended by 2s-5s; when the pressure difference is detected to be higher than the preset upper limit, the duty cycle of the ventilation component 8 is reduced to avoid excessive ventilation to eliminate spatial gradient characteristics.

[0066] (2) Particulate filter 11 The particulate filter 11 is located at the front end of the sampling pump 16 to intercept dust, fruit debris and condensation mist in the sampling gas, protect the valve assembly and sensor, and avoid performance degradation caused by contamination.

[0067] (3) Current stabilizer 12 The flow stabilizer 12 is located between the outlet of the sampling pump 16 and the multi-way switching valve 17. It uses a stainless steel throttling orifice with a diameter of 0.5mm to 1mm and a pressure compensation structure to suppress transient flow fluctuations during multi-way switching and disturbance stages, ensure stable gas flow into the ethylene sensor 14, and improve the repeatability of detection data.

[0068] (4) Condensate trap 10 The condensate collector 10 is located between the gas intake port and the multi-way switching valve 17, and is installed below all gas intake ports. It adopts a transparent cup structure or hydrophobic membrane assembly, and is equipped with a manual drain valve or automatic drain mechanism at the bottom to collect condensate in the sampled gas, so as to prevent liquid water from entering the valve group and sensor, which could cause hardware damage or detection distortion.

[0069] (5) Auxiliary calibration branch 13 The auxiliary calibration branch 13 is connected in series with the ethylene removal module 18. Its input is connected to a fresh air source, and its output is connected to the calibration port of the multi-way switching valve 17. The ethylene removal module 18 uses a potassium permanganate impregnation medium or a room-temperature catalytic oxidation medium, which can completely remove ethylene from the air and output a stable zero-ethylene reference gas.

[0070] Correspondingly, the controller also includes an auxiliary calibration control module. When the system does not execute the complete ethylene source determination process, the auxiliary calibration control module periodically controls the auxiliary calibration branch 13 to introduce zero ethylene reference gas, completes the zero-point calibration and cross-response background evaluation of each sensor, and ensures the long-term stability of the detection data.

[0071] In summary, the online ethylene detection system for ripening post-ripening fruits provided in this embodiment achieves online identification, decoupling characterization, and decision support for ripening operations by using multi-location differentiated gas sampling, single-sensor polling measurement, paired controlled disturbance excitation, silent observation verification, and decoupling determination of ethylene sources.

[0072] Example 2: Based on the online ethylene detection system for ripening post-ripening fruits provided in Example 1 above, this example also provides an online ethylene detection method for ripening post-ripening fruits. This method is completely consistent with the system scheme. Based on the essential differences in the characteristics of different ethylene sources, it achieves online decoupling determination of ethylene sources through a multi-stage progressive detection process.

[0073] It should be noted that, in order to ensure comparability between different test batches, it is preferable to keep the gas intake location, perturbation procedure, sampling frequency, silent observation window duration, and threshold calling strategy consistent within the same batch.

[0074] This method specifically includes the following steps. Step S100, Multi-location baseline acquisition step: Gas and ethylene concentration are sequentially collected from the mainstream region representing the overall mixed atmosphere within the ripening space, the boundary layer region near the wall, and the region above the surface of the fruit pile, respectively, to obtain the mainstream ethylene baseline concentration. Near-wall vinyl line concentration Near-fruit pile vinyl line concentration And calculate the near-wall baseline gradient. Near-field baseline gradient To establish a spatial concentration benchmark under undisturbed steady state, a unified reference is provided for all subsequent dynamic characteristic calculations. Preferably, after each switch, a purging process is performed first, and then the median concentration within the stable segment is taken as the vinyl line concentration.

[0075] Step S200, Forward Perturbation Step: Apply a standardized and repeatable forward perturbation to the ripening space. During the perturbation process, continuously collect concentration time series data for three regions at a sampling frequency of not less than 1 Hz. , , Extract the peak overshoot at each location. , , and gradient evolution curve , The changing characteristics actively stimulate the differences in sensitivity of different source terms to disturbances, providing the first layer of core evidence for source term determination.

[0076] Step S300, Reverse Perturbation and Recovery Step: Apply a reverse perturbation that corresponds exactly to the forward perturbation, remove the external excitation, and continuously acquire the concentration time series during the recovery phase. , , The recovery time constant at each location was obtained by first-order exponential fitting. , , The hysteresis area at each position was calculated by performing a trapezoidal integral on the relative vinyl line concentration increment curve. , , The recovery characteristics that distinguish between transient desorption and release and sustained endogenous release provide a second layer of core evidence for source term determination.

[0077] Step S400, Silent Observation Step: Under low-disturbance steady-state conditions with no external ethylene injection, constant ventilation, and no disturbances, concentration data are continuously collected for a preset duration. The accumulation slope at the mainstream position is calculated using a univariate linear regression method. S m Accumulated slope near the wall S w Accumulated slope near the fruit pile S f And calculate the average near-wall gradient within the silent observation window. Near-heap gradient average and mainstream average concentration This verifies the continuous release characteristics of different source terms, eliminates transient interference caused by disturbances, and provides a third layer of core evidence for source term determination.

[0078] Step S500, Source Decoupling Determination Step: Based on the differences in peak overshoot obtained at each location during the forward perturbation step, the differences in recovery time constant and hysteresis area obtained during the reverse perturbation and recovery steps, the differences in accumulation slope obtained during the silent observation step, and the gradient evolution characteristics, the ethylene source in the ripening space is decoupled and determined to be at least one of the following: uniform residue, wall / packaging memory release, and endogenous gas release from the fruit. When the determination condition for only one type of source term is met, a single source determination result is output; when the determination conditions for two or more types of source terms are met simultaneously, a mixed source determination result is output, and the contribution ranking of each source term is determined by the intensity index. The thresholds T1 to T7 are preferably determined jointly based on single source term calibration experiments and historical valid operating data.

[0079] Step S600, Result Output and Update Steps: The entire detection process data is structured and recorded as a standardized environmental detection fingerprint to achieve full traceability; based on the environmental detection fingerprint, the historical feature parameters across batches are updated using an exponentially weighted moving average algorithm to achieve adaptive optimization for the next batch of detection; based on the source decoupling judgment results and combined with the fruit ripening process requirements, targeted on-site operation suggestions are generated to achieve a closed loop of detection and decision-making.

[0080] In a specific embodiment of the present invention, ventilation has been performed after the previous batch operation, and a small amount of adsorbed residue remains on the inner wall of the cabinet. The loaded avocados are close to the initial stage of endogenous gas release. The detection process and results using this method are as follows: First, execute step S100 to obtain the baseline acquisition results: =0.85ppm =1.02ppm =0.98ppm, =0.17ppm =0.13ppm; Then, step S200 is executed, a positive perturbation is applied, and the peak overshoot is extracted: =0.52ppm =0.28ppm =0.22ppm; Then, execute step S300, apply the reverse perturbation and collect the recovered data, and fit the data to obtain the recovery time constant: =10s =25s =20s, calculate the hysteresis area: =3.5ppm·s =1.2ppm·s; Then, step S400 is executed, entering a 5-minute silent observation phase, and the accumulated slope is obtained through fitting: =0.003ppm / min =0.035ppm / min, =0.032ppm / min; Finally, step S500 is executed to complete the source decoupling determination: on the one hand, =0.30ppm ≥ preset threshold 0.2ppm, =3.5ppm·s ≥ preset threshold 0.5ppm·s, and =10s< =25s, meeting the criteria for wall / packaging memory release; on the other hand, =0.032ppm / min ≥ preset threshold 0.02ppm / min, =25s> =10s, meeting the criteria for endogenous gas release from the fruit; the absolute value of the initial gradient is greater than the preset spatial gradient threshold of 0.05ppm, failing to meet the criteria for uniform residue. Final output result: mixed sources (wall / packaging memory release + endogenous gas release from the fruit), intensity index =2.6、 =1.8, and the contribution from the sources is ranked as follows: wall / packaging memory release > fruit endogenous gas release.

[0081] Execute step S600 synchronously and output priority-based operation suggestions: First priority, perform 10 minutes of ventilation and air exchange, clean the inner wall and air duct of the ripening cabinet, check the adsorption residue of the packaging liner, and eliminate the memory release source on the wall; Second priority, after the ventilation is completed, there is no need to perform high-concentration external ethylene injection, adopt low-concentration ethylene maintenance process, shorten the ripening cycle, monitor the internal gas release intensity daily, and avoid over-ripening.

[0082] Example 3: Based on the system provided in Example 1 and the method provided in Example 2, this example provides a computer device that executes the method described in Example 2 or any other method that may involve the method described in Example 2. The device includes a memory, a processor, and a transceiver connected in sequence. The memory stores a computer program, the transceiver sends and receives messages, and the processor reads the computer program and executes the method described in Example 2 or any other method that may involve the method described in Example 2. Specifically, the memory may include, but is not limited to, random-access memory (RAM), read-only memory (ROM), flash memory, first-in-first-out (FIFO) memory, and / or last-in-first-out (FILO) memory, etc.; the processor may include, but is not limited to, a microprocessor of the STM32F105 series. Furthermore, the computer device may also include, but is not limited to, a power module, a display screen, and other necessary components.

[0083] The working process, working details and technical effects of the aforementioned computer device provided in this embodiment can be found in the method described in Embodiment 2 or any method that may involve the method described in Embodiment 2, and will not be repeated here.

[0084] Example 4: This example provides a computer-readable storage medium that stores instructions that include the method described in Example 2 or any other method that may involve the method described in Example 2. Specifically, the computer-readable storage medium stores instructions that, when executed on a computer, perform the method described in Example 2 or any other method that may involve the method described in Example 2. The computer-readable storage medium refers to a data storage medium, which may include, but is not limited to, floppy disks, optical disks, hard disks, flash memory, USB flash drives, and / or Memory Sticks. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices.

[0085] The working process, working details and technical effects of the aforementioned computer-readable storage medium provided in this embodiment can be found in the method described in Embodiment 2 or any method that may be related to Embodiment 2, and will not be repeated here.

[0086] Example 5: This example provides a computer program product containing instructions that, when executed on a computer, cause the computer to perform the method described in Example 2 or any method that may involve the method described in Example 2. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device.

[0087] It should be understood that the terms "system," "device," "unit," and / or "module" as used in this specification are a method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0088] As indicated in this specification and claims, unless the context clearly indicates otherwise, the words "a," "an," "an," and / or "the" do not specifically refer to the singular and may also include the plural. Generally speaking, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements.

[0089] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0090] It should be noted that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the disclosed technical content. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

Claims

1. An online detection system for ethylene in the ripening environment of post-ripening fruits, characterized in that, include: The sampling circuit includes: a main air intake (5), located in the return air main area in the middle of the ripening space; a near-wall air intake (6), located in the near-wall area of ​​the laminar flow boundary layer near the box wall, the inner wall of the air duct, the liner and the inner wall of the packaging in the ripening space; a near-fruit pile air intake (7), located in the near-fruit pile area near the surface of the fruit pile; a sampling component, used to sequentially transport the gas from the main air intake (5), the near-wall air intake (6) and the near-fruit pile air intake (7) to the ethylene sensor (14); and an ethylene sensor (14), used to collect the ethylene concentration in the gas. The controlled disturbance excitation unit is used to apply positive and negative disturbances to the ripening space. The positive disturbance is used to reduce the thickness of the laminar boundary layer, increase the airflow velocity in the near-wall region, and increase the gas exchange rate between the laminar boundary layer and the return air mainstream region. The negative disturbance is used to restore the gas conditions of the ripening space from the unsteady conditions after the positive disturbance to the baseline conditions. The controller, connected to the sampling component, ethylene sensor (14), and controlled disturbance excitation unit, includes the following components connected in series: a baseline acquisition module for acquiring the near-wall baseline gradient and near-fruit pile baseline gradient based on the vinyl line concentration at each gas inlet; a first feature extraction module for extracting the peak overshoot and gradient evolution characteristics at each gas inlet based on the ethylene concentration sequence at each gas inlet during the forward disturbance process; a second feature extraction module for calculating the recovery time constant and hysteresis area at each gas inlet based on the ethylene concentration sequence at each gas inlet during the reverse disturbance and recovery process; a silent observation and analysis module for acquiring the accumulation slope at each gas inlet based on the ethylene concentration sequence acquired under the condition of no external ethylene injection and unchanged gas exchange state; and a source decoupling determination module for determining the ethylene source in the ripening space based on the peak overshoot, gradient evolution characteristics, recovery time constant, hysteresis area, and accumulation slope, and outputting the determination result.

2. The online ethylene detection system for ripening post-ripening fruits according to claim 1, characterized in that, The distance from the main return air area to the top or bottom of the ripening space is 0.4 to 0.6 times the total height of the ripening space; the distance from the near-wall area to the box wall, the inner wall of the air duct, the liner and the inner wall of the packaging is 20mm to 80mm. The distance from the area near the fruit pile to the surface of the fruit pile is 20mm to 120mm; The sampling components include: a multi-way switching valve (17), a sampling pump (16), and sampling tubing; The controlled disturbance excitation unit includes: The circulating fan speed change assembly (19) is used to reduce the thickness of the laminar troposphere or restore the flow field of the laminar troposphere to a steady state by step change of the fan speed. The pulsed suction assembly (15) is used to apply local disturbances to the laminar boundary layer by suction. Local boundary layer disturbance jet assembly (20) is used to apply directional jets to the laminar boundary layer; The ventilation assembly (8) is used to introduce outside air into the ripening space by opening the ventilation valve.

3. The online ethylene detection system for ripening post-ripening fruits according to claim 2, characterized in that, The circulating fan speed control assembly (19) includes: a condition switching unit, used to increase the fan speed from the first condition v1 to the second condition v2 during the positive disturbance phase, and to return the fan speed from the second condition v2 to the first condition v1 during the reverse disturbance phase; the fan speed under the second condition v2 is 10% to 60% higher than the fan speed under the first condition v1; The pulse suction component (15) is installed on the sampling pipeline; the duration of strong suction is 2s to 15s; The local boundary layer disturbance jet assembly (20) is set in the near-wall region; the duration of the directional jet is 1s to 8s; the direction of the directional jet is parallel to the wall or at an angle of 10° to 45°.

4. The online ethylene detection system for ripening post-ripening fruits according to claim 1, characterized in that, The formula for calculating the near-wall baseline gradient is: ;in, For near-wall baseline gradient, The near-wall vinyl line concentration at the near-wall gas intake (6) is the concentration of vinyl line near the wall. The concentration of the mainstream vinyl line at the mainstream gas intake (5); The formula for calculating the near-row baseline gradient is: ;in, The gradient is the near-baseline gradient of the fruit pile. The concentration of vinyl line near the fruit pile gas inlet (7); Peak overshoot includes: mainstream peak overshoot, near-wall peak overshoot, and near-cluster peak overshoot; among which, the formula for calculating mainstream peak overshoot is: , The mainstream peak overshoot, The ethylene concentration sequence at the main gas intake (5) during the positive disturbance is given, where t1 is the start time of the positive disturbance and t2 is the end time of the positive disturbance. The formula for calculating the near-wall peak overshoot is: , This refers to the near-wall peak overshoot. The ethylene concentration sequence at the near-wall gas intake (6) during positive perturbation; the formula for calculating the peak overshoot near the fruit pile is: , This is the near-peak overshoot of the fruit pile. The ethylene concentration sequence at the near-fruit pile gas inlet (7) during positive perturbation; Gradient evolution characteristics include: near-wall gradient evolution curve, near-cushion gradient evolution curve, peak value, mean, zero-crossing time, and monotonicity of the near-wall gradient evolution curve, and the peak value, mean, zero-crossing time, and monotonicity of the near-cushion gradient evolution curve; the near-wall gradient evolution curve is represented as: The near-gravity gradient evolution curve is represented as follows: , This represents the near-wall gradient evolution curve. This represents the gradient evolution curve of the near-fruit pile; The recovery time constants include: the recovery time constant at the main gas intake (5), the recovery time constant at the near-wall gas intake (6), and the recovery time constant at the near-fruit pile gas intake (7); the recovery time constants at the main gas intake (5), the near-wall gas intake (6), and the near-fruit pile gas intake (7) are obtained by fitting the ethylene concentration sequence at the corresponding gas intake after reverse perturbation according to the first-order exponential decay model; the fitting model is: ; i Indicates the air intake point. , m This indicates the location of the main air intake (5). w This indicates the location of the near-wall air intake (6). This indicates the location of the air intake (7) near the fruit pile; t Indicates time; This indicates that after the reverse disturbance is applied, the air intake... i exist t Ethylene concentration at any given time, in ppm; Indicates air intake port i Vinyl concentration, in ppm; When the positive disturbance ends, the gas intake port i The peak ethylene concentration, in ppm; The time of initiation of the reverse disturbance is expressed in seconds. Let i be the recovery time constant of the air intake port; The hysteresis area includes: the hysteresis area at the main gas intake (5), the hysteresis area at the near-wall gas intake (6), and the hysteresis area at the near-fruit pile gas intake (7); the hysteresis areas at the main gas intake (5), the near-wall gas intake (6), and the near-fruit pile gas intake (7) are obtained by performing trapezoidal integration on the relative vinyl line concentration increment at the corresponding gas intake over the time period from the start time t1 of the positive disturbance to the end time te of the recovery; the formula for calculating the relative vinyl line concentration increment is: ;in, Indicates air intake port i exist t The relative baseline increment at any given time.

5. The online ethylene detection system for ripening post-ripening fruits according to claim 4, characterized in that, The source decoupling determination module includes: The memory ethylene determination unit is used when... ≥ First near-wall judgment threshold T1, cumulative value of relative vinyl line concentration increment at near-wall gas intake (6) ≥ the second near-wall determination threshold T2, and When the recovery time difference threshold T3 is greater than or equal to the threshold value, memory ethylene is determined to exist in the ripening space; where, The first near-wall detection threshold T1 = 0.20 ppm, the second near-wall detection threshold T2 = 0.50 ppm·s, and the recovery time difference threshold T3 = 5 s. Endogenous ethylene determination unit, used when ≥ the gas release slope threshold T4, and When the recovery hysteresis threshold T5 is reached, it is determined that there is endogenous ethylene continuously released from the fruit. Let be the accumulation slope at the gas intake (7) near the fruit pile. The accumulation slope at the main gas intake (5); the gas release slope threshold T4 = 0.02 ppm / min, and the recovery hysteresis threshold T5 = 4 s; The residual ethylene determination unit is used when the absolute value of the near-wall baseline gradient mean is... < Spatial gradient threshold T6, and the average ethylene concentration in the mainstream region >When the background threshold T7 is reached, residual ethylene is determined to be present; This represents the average near-wall gradient within the silent observation window. The average concentration of the mainstream within the silent observation window; spatial gradient threshold T6 = 0.05 ppm, background threshold T7 = 0.50 ppm; The judgment result output unit is used to output the judgment result of a single ethylene source when only one type of ethylene source meets the corresponding judgment condition; when at least two types of ethylene source items meet the corresponding judgment condition at the same time, the source decoupling judgment module outputs the judgment result of mixed ethylene source.

6. The online ethylene detection system for ripening post-ripening fruits according to claim 5, characterized in that, The source decoupling determination module also includes: The intensity index calculation unit is used to quantitatively characterize the intensity of ethylene source items and output the intensity index of each ethylene source item, including: wall memory release intensity index, fruit endogenous gas release intensity index, and uniform residual intensity index. The formula for calculating the wall surface memory release strength index is: ; The formula for calculating the endogenous gas release intensity index of fruits is: ; The formula for calculating the uniform residual strength index is: ; The wall memory release intensity index, This is an indicator of the endogenous gas release intensity of fruits. For uniform residual strength index, , The reference hysteresis area can be calibrated through a pure wall release test under standard operating conditions; This is the reference background concentration under uniform residual conditions; The average gradient of the near-fruit pile; The cumulative slope at the near-wall gas intake (6); All are weighted coefficients.

7. The online ethylene detection system for ripening post-ripening fruits according to claim 1, characterized in that, The controller also includes: The environmental monitoring fingerprint acquisition module is used to structurally record the entire monitoring process data into standardized environmental monitoring fingerprints, and store the environmental monitoring fingerprints locally or upload them to a host computer. The environmental monitoring fingerprints adopt a standardized JSON format or a structured database record format, and include at least: basic monitoring information, baseline acquisition data, disturbance response characteristic data, silent observation data, environmental parameter data, judgment result data, operation suggestion data, and anomaly information. The basic monitoring information includes at least: monitoring date, batch number, fruit variety number, packaging form, ripening space number, and disturbance program number. The historical data update module is used to update historical parameters using an exponentially weighted moving average algorithm. Historical parameters include: historical wall memory release level, historical fruit gas release level, and historical uniform residue level. The formula for updating the level of historical wall memory release is: ; The updated formula for historical fruit gas release levels is: ; The formula for updating the historical uniform residual level is: ; in, k This is the current batch number. k -1 represents the previous batch number. This represents the wall memory release level for the current batch. This represents the gas release level of the current batch of fruit. This represents the uniform residue level for the current batch. The wall memory release level is the same as the previous batch. The gas release level is based on the previous batch of fruit. The uniform residue level of the previous batch, α For smoothing coefficients, α Take a value of 0.1 to 0.

3. This refers to the wall memory release intensity index for the current batch. This is an indicator of the endogenous gas release intensity of the current batch of fruit. This represents the uniform residual strength index for the current batch.

8. The online ethylene detection system for ripening post-ripening fruits according to claim 2, characterized in that, Also includes: The environmental parameter acquisition unit is used to record temperature, humidity, wind speed, and pressure difference information in real time throughout the entire detection process; The environmental parameter acquisition unit includes: a temperature sensor (1), a humidity sensor (2), a wind speed sensor (3), and a differential pressure sensor (4); A particulate filter (11) is installed at the front end of the sampling pump (16); A flow stabilizer (12) is installed between the outlet of the sampling pump (16) and the multi-way switching valve (17); A condensate trap (10) is installed between the air intake and the multi-way switching valve (17) and its installation position is lower than the air intake. Ethylene removal module (18) for removing ethylene from the air; The auxiliary calibration branch (13) is connected in series with the ethylene removal module (18); the input end of the auxiliary calibration branch (13) is connected to the fresh air source, and the output end of the auxiliary calibration branch (13) is connected to the calibration port of the multi-way switching valve (17). The controller also includes: The environment adaptive adjustment module is used to dynamically adjust the disturbance amplitude, sampling frequency, emptying time, and observation window duration according to environmental parameters.

9. A method for online detection of ethylene in the ripening environment of post-ripening fruits, characterized in that, Includes the following steps: Gas and ethylene concentration were collected sequentially from the return air mainstream area, near-wall area, and near-fruit pile area of ​​the ripening space to obtain the vinyl line concentration of each area. The near-wall baseline gradient and near-fruit pile baseline gradient were obtained based on the vinyl line concentration of each area. The return air mainstream area is located in the middle of the ripening space, the near-wall area is located in the laminar boundary layer of the ripening space near the box wall, the inner wall of the air duct, the liner, and the inner wall of the packaging, and the near-fruit pile area is near the top of the fruit pile surface. A positive perturbation is applied to the ripening space, and the ethylene concentration sequence of each region is collected during the perturbation process. The peak overshoot and gradient evolution characteristics of each region are extracted. The positive perturbation is used to reduce the thickness of the laminar boundary layer, increase the airflow velocity in the near-wall region, and increase the gas exchange rate between the laminar boundary layer and the return air mainstream region. A reverse perturbation is applied to the ripening space. During the reverse perturbation and recovery process, the ethylene concentration sequence of each region is collected, and the recovery time constant and hysteresis area of ​​each region are calculated. The reverse perturbation is used to restore the gas conditions of the ripening space from the unsteady conditions after the forward perturbation to the baseline conditions. The accumulation slope of each region was obtained based on the ethylene concentration sequence collected under the condition of no external ethylene injection and constant ventilation. Based on the peak overshoot, gradient evolution characteristics, recovery time constant, hysteresis area, and accumulation slope, the source of ethylene in the ripening space is determined, and the determination result is output.

10. The method for online detection of ethylene in the ripening environment of post-ripening fruits according to claim 9, characterized in that, The formula for calculating the near-wall baseline gradient is: ;in, For near-wall baseline gradient, The near-wall vinyl line concentration at the near-wall gas intake (6) is the concentration of vinyl line near the wall. The concentration of the mainstream vinyl line at the mainstream gas intake (5); The formula for calculating the near-row baseline gradient is: ;in, For the near-fruit pile baseline gradient, The concentration of vinyl line near the fruit pile gas inlet (7) is the concentration of vinyl line near the fruit pile. Main air intake (5) is located in the return air mainstream area in the middle of the ripening space; near wall air intake (6) is located in the near wall area of ​​the laminar flow boundary layer near the box wall, the inner wall of the air duct, the liner and the inner wall of the packaging in the ripening space; near fruit pile air intake (7) is located in the near fruit pile area near the surface of the fruit pile. Peak overshoot includes: mainstream peak overshoot, near-wall peak overshoot, and near-cluster peak overshoot; among which, the formula for calculating mainstream peak overshoot is: , The mainstream peak overshoot, The ethylene concentration sequence at the main gas intake (5) during the positive disturbance is given, where t1 is the start time of the positive disturbance and t2 is the end time of the positive disturbance. The formula for calculating the near-wall peak overshoot is: , This refers to the near-wall peak overshoot. The ethylene concentration sequence at the near-wall gas intake (6) during positive perturbation; the formula for calculating the peak overshoot near the fruit pile is: , This is the near-peak overshoot of the fruit pile. The ethylene concentration sequence at the near-fruit pile gas inlet (7) during positive perturbation; Gradient evolution characteristics include: near-wall gradient evolution curve, near-cushion gradient evolution curve, peak value, mean, zero-crossing time, and monotonicity of the near-wall gradient evolution curve, and the peak value, mean, zero-crossing time, and monotonicity of the near-cushion gradient evolution curve; the near-wall gradient evolution curve is represented as: The near-gravity gradient evolution curve is represented as follows: , This represents the near-wall gradient evolution curve. This represents the gradient evolution curve of the near-fruit pile; The recovery time constants include: the recovery time constant at the main gas intake (5), the recovery time constant at the near-wall gas intake (6), and the recovery time constant at the near-fruit pile gas intake (7); the recovery time constants at the main gas intake (5), the near-wall gas intake (6), and the near-fruit pile gas intake (7) are obtained by fitting the ethylene concentration sequence at the corresponding gas intake after reverse perturbation according to the first-order exponential decay model; the fitting model is: ; i Indicates the air intake point. , m This indicates the location of the main air intake (5). w This indicates the location of the near-wall air intake (6). This indicates the location of the air intake (7) near the fruit pile; t Indicates time; This indicates that after the reverse disturbance is applied, the air intake... i exist t Ethylene concentration at any given time, in ppm; Indicates air intake port i Vinyl concentration, in ppm; When the positive disturbance ends, the gas intake port i The peak ethylene concentration, in ppm; The time of initiation of the reverse disturbance is expressed in seconds. Let i be the recovery time constant of the air intake port; The hysteresis area includes: the hysteresis area at the main gas intake (5), the hysteresis area at the near-wall gas intake (6), and the hysteresis area at the near-fruit pile gas intake (7); the hysteresis areas at the main gas intake (5), the near-wall gas intake (6), and the near-fruit pile gas intake (7) are obtained by performing trapezoidal integration on the relative vinyl line concentration increment at the corresponding gas intake over the time period from the start time t1 of the positive disturbance to the end time te of the recovery; the formula for calculating the relative vinyl line concentration increment is: ;in, Indicates air intake port i exist t The relative baseline increment at any given time.

11. The method for online detection of ethylene in the ripening environment of post-ripening fruits according to claim 10, characterized in that, Determining the source of ethylene within the ripening space includes: when ≥ First near-wall judgment threshold T1, cumulative value of relative vinyl line concentration increment at near-wall gas intake (6) ≥ the second near-wall determination threshold T2, and When the recovery time difference threshold T3 is greater than or equal to the threshold value, memory ethylene is determined to exist in the ripening space; where, The first near-wall detection threshold T1 = 0.20 ppm, the second near-wall detection threshold T2 = 0.50 ppm·s, and the recovery time difference threshold T3 = 5 s. when ≥ the gas release slope threshold T4, and When the recovery hysteresis threshold T5 is reached, it is determined that there is endogenous ethylene continuously released from the fruit. Let be the accumulation slope at the gas intake (7) near the fruit pile. The accumulation slope at the main gas intake (5); the gas release slope threshold T4 = 0.02 ppm / min, and the recovery hysteresis threshold T5 = 4 s; When the absolute value of the near-wall baseline gradient mean < Spatial gradient threshold T6, and the average ethylene concentration in the mainstream region >When the background threshold T7 is reached, residual ethylene is determined to be present; This represents the average near-wall gradient within the silent observation window. The average concentration of the mainstream within the silent observation window; spatial gradient threshold T6 = 0.05 ppm, background threshold T7 = 0.50 ppm; When only one type of ethylene source meets the corresponding judgment condition, the single source judgment result is output; when at least two types of ethylene source items meet the corresponding judgment condition at the same time, the source decoupling judgment module outputs the mixed ethylene source judgment result.

12. The method for online detection of ethylene in the ripening environment of post-ripening fruits according to claim 11, characterized in that, It also includes the following steps: The intensity of ethylene source terms is quantitatively characterized, and the intensity index of each ethylene source term is output, including: wall memory release intensity index, fruit endogenous gas release intensity index, and uniform residual intensity index. The formula for calculating the wall surface memory release strength index is: ; The formula for calculating the endogenous gas release intensity index of fruits is: ; The formula for calculating the uniform residual strength index is: ; The wall memory release intensity index, This is an indicator of the endogenous gas release intensity of fruits. For uniform residual strength index, , The reference hysteresis area can be calibrated through a pure wall release test under standard operating conditions; This is the reference background concentration under uniform residual conditions; The average gradient of the near-fruit pile; The cumulative slope at the near-wall gas intake (6); All are weighted coefficients.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements an online detection method for ethylene in the ripening environment of post-ripening fruits as described in any one of claims 9 to 12.

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