A control system for a yoghurt fermentation device

Abstract

The present application relates to the technical field of intelligent fermentation, and particularly relates to a control system of a yogurt fermentation device, which comprises a collection module, a trigger generation module, a determination module, an identification module, a rate adjustment module, a correction module and a threshold adjustment module. The present application collects key parameters in the tank in real time, discovers preliminary risks such as high temperature or abnormal acidity in the tank in time, judges the abnormal type through the change of the lactic acid generation rate and the curd viscosity, calculates an abnormal index to adjust the stirring rate, corrects the adjustment result through the whey precipitation rate, ensures that the lactic acid accumulation and the curd formation maintain a reasonable proportion, automatically adjusts the temperature threshold according to the fluctuation of the corrected stirring rate within a certain time, forms a dynamic balance among the temperature, the pH value, the lactic acid generation rate and the curd viscosity, and effectively solves the problem that the fermentation abnormality is difficult to be identified and adjusted in time due to single parameter monitoring and experience threshold judgment.

Description

Technical Field

[0001] This invention relates to the field of intelligent fermentation technology, and in particular to a control system for a yogurt fermentation device. Background Technology

[0002] As the dairy market continues to demand high-quality yogurt and functional fermented dairy products, higher requirements are being placed on fermentation consistency, taste stability, and microbial activity control during the production process. At the same time, factors such as fluctuations between production batches, changes in ambient temperature, and differences in raw materials pose significant challenges to stable fermentation.

[0003] In existing technologies, yogurt fermentation typically relies on manual experience or preset temperature and stirring methods for control. While some high-end production lines have introduced single-parameter monitoring systems such as online pH monitoring, temperature acquisition, or dissolved oxygen measurement, these systems mostly operate independently and lack comprehensive analysis of the interactions between multiple key indicators. Although some processes employ constant stirring or constant temperature strategies, they are not sensitive enough to dynamic changes during fermentation and cannot promptly capture abnormal fluctuations in parameters such as whey separation rate, curd viscosity, and lactic acid formation rate. Furthermore, existing methods rely heavily on empirical thresholds or simple rules for anomaly identification and adjustment, lacking a comprehensive judgment mechanism for anomaly trends, fluctuation amplitudes, and time series, thus limiting the stability and repeatability of the fermentation process.

[0004] It is evident that existing technologies have the following problems: single-parameter monitoring is prone to misjudgment and cannot promptly identify complex anomalies or potential abnormal trends; consistency between fermentation batches is difficult to guarantee; and the response to key indicators such as temperature, stirring, and lactic acid production is lagging, resulting in large fluctuations in fermentation results and high difficulty in quality control. Summary of the Invention

[0005] To address this, the present invention provides a control system for a yogurt fermentation device, which overcomes the problem in the prior art that fermentation abnormalities are difficult to identify and adjust in a timely manner due to single parameter monitoring and experience threshold judgment by real-time acquisition of key process parameters and joint analysis of multiple indicators.

[0006] To achieve the above objectives, the present invention provides a control system for a yogurt fermentation apparatus, comprising:

[0007] The data acquisition module is used to collect data in real time on the temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey separation rate, curd viscosity, and lactic acid production rate inside the yogurt fermentation tank, which is running at a preset stirring rate.

[0008] A trigger generation module, which is connected to the acquisition module, is used to generate a triggering abnormality result corresponding to the occurrence of suspected fermentation abnormality based on the tank temperature and a preset temperature threshold.

[0009] The determination module is connected to the trigger generation module and the acquisition module respectively, and is used to determine the occurrence of actual abnormalities based on the pH value and the whey precipitation rate of the tank wall within a preset screening time, so as to obtain the abnormality result to be processed.

[0010] An identification module, which is connected to the judgment module and the acquisition module respectively, is used to identify the abnormal elements corresponding to the abnormal result to be processed based on the curd viscosity and the lactic acid generation rate.

[0011] A rate adjustment module, which is connected to the identification module and the acquisition module respectively, is used to determine the corresponding abnormal index based on the abnormal element, and to adjust the preset stirring rate according to the abnormal index to obtain the adjusted stirring rate;

[0012] A correction module, which is connected to the rate adjustment module, is used to correct the adjusted stirring rate based on the whey precipitation rate of the tank wall after the adjusted stirring rate is obtained, so as to obtain a corrected stirring rate.

[0013] A threshold adjustment module, which is connected to the correction module and the trigger generation module respectively, is used to adjust the preset temperature threshold according to the correction stirring rate within the preset threshold adjustment time.

[0014] Furthermore, the trigger generation module includes:

[0015] A comparison unit is used to compare the temperature inside the tank with a preset temperature threshold to obtain a temperature comparison result;

[0016] A generation unit, connected to the comparison unit, is used to determine a suspected fermentation abnormality when the temperature comparison result indicates that the temperature inside the tank is greater than the preset temperature threshold, and to generate the triggering abnormality result corresponding to the suspected fermentation abnormality.

[0017] Furthermore, the determination module includes:

[0018] The analysis unit is used to perform time-series analysis on the pH value and the whey precipitation rate from the tank wall within a preset screening time to obtain continuous abnormal results.

[0019] An index determination unit, connected to the analysis unit, is used to determine a joint anomaly index based on the persistent anomaly results, according to the pH value and the whey precipitation rate from the tank wall.

[0020] The determination unit is used to determine the occurrence of the actual anomaly when the joint anomaly index is greater than the preset standard joint index, so as to obtain the result of the anomaly to be processed.

[0021] Furthermore, the analysis unit includes:

[0022] The rate of change calculation subunit is used to calculate the rate of change of pH value during the continuous decrease period when the pH value continuously decreases within the preset screening time, and to obtain the pH decrease rate; and to calculate the rate of change of whey separation rate of tank wall during the continuous increase period when the whey separation rate of tank wall continuously increases within the preset screening time, and to obtain the whey separation rate change value.

[0023] An analysis subunit, connected to the rate of change calculation subunit, is used to determine the existence of a continuous abnormal fermentation trend within the preset screening time when the pH decrease rate is greater than a preset pH decrease rate threshold and the whey separation rate change value is greater than a preset rate change value threshold, so as to obtain the continuous abnormal result.

[0024] Furthermore, the index determination unit includes:

[0025] The rate calculation subunit is used to calculate the difference between the pH value at each moment during the continuous decreasing time period and the pH value at the initial moment to obtain several pH change rates, and to calculate the difference between the whey precipitation rate of the tank wall at each moment during the continuous increasing time period and the whey precipitation rate of the tank wall at the initial moment to obtain several precipitation change rates.

[0026] The index determination subunit is used to perform a weighted summation calculation on the average value of all pH change rates, a preset first weight, the average value of all precipitation change rates, and a preset second weight to obtain the joint anomaly index.

[0027] Furthermore, the identification module includes:

[0028] The feature extraction unit is used to extract the growth rate of the curd viscosity within the same preset screening time to obtain the viscosity growth rate, and to extract the average value of the lactic acid generation rate within the same preset screening time to obtain the average generation rate.

[0029] An identification unit, connected to the feature extraction unit, is used to identify the abnormal element as a composite abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold; to identify the abnormal element as a solidification abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is greater than a preset average generation threshold; and to identify the abnormal element as an acidification abnormality when the viscosity growth rate is less than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold.

[0030] Furthermore, the rate adjustment module includes:

[0031] The first abnormality index calculation unit is used to calculate the abnormality index based on the tank temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, tank wall whey precipitation rate, curd viscosity and lactic acid generation rate within the same preset screening time when the abnormal element is the composite abnormality.

[0032] The second calculation unit for the abnormality index is used to calculate the abnormality index based on the coagulation viscosity, the stirring power, and the tank wall adhesion rate within the same preset screening time when the abnormal element is the coagulation abnormality or the acidification abnormality.

[0033] A rate adjustment unit is connected to the first abnormality index calculation unit and the second abnormality index calculation unit, respectively, and is used to adjust the preset stirring rate according to the abnormality index and the preset abnormality index threshold when the abnormality index is greater than the preset abnormality index threshold, so as to obtain the adjusted stirring rate.

[0034] Furthermore, the correction module includes:

[0035] The velocity fluctuation value calculation unit is used to calculate the standard deviation of the whey precipitation rate of all the tank walls within a preset correction time to obtain the precipitation velocity fluctuation value.

[0036] The correction unit is used to correct the adjusted stirring rate based on the relative deviation between the speed fluctuation value and the preset speed fluctuation threshold and a preset correction coefficient when the speed fluctuation value is greater than the preset speed fluctuation threshold, so as to obtain the corrected stirring rate.

[0037] Furthermore, the threshold adjustment module includes:

[0038] The number of times acquisition unit is used to acquire the number of times and timestamps of the correction of the abnormal index calculated by the first calculation unit of the abnormal index within the preset threshold adjustment time to obtain the first number and several first moments, and to acquire the number of times and timestamps of the correction of the abnormal index calculated by the second calculation unit of the abnormal index within the preset threshold adjustment time to obtain the second number and several second moments.

[0039] A threshold adjustment unit, connected to the count acquisition unit, is used to adjust the preset temperature threshold based on the first count, the first time, the second count, and the second time.

[0040] Further, the threshold adjustment unit includes:

[0041] The dispersion calculation subunit is used to calculate the standard deviation of the difference between the first time and the second time and the initial time when both the first number and the second number are greater than a preset number threshold, to obtain the total time dispersion; and to calculate the standard deviation of the difference between all the first time and the initial time when the first number is greater than the preset number threshold and the second number is less than or equal to the preset number threshold, to obtain the first time dispersion; and to calculate the standard deviation of the difference between all the second time and the initial time when the second number is greater than the preset number threshold and the first number is less than or equal to the preset number threshold, to obtain the second time dispersion.

[0042] A threshold adjustment subunit, connected to the dispersion calculation subunit, is used to adjust the preset temperature threshold based on the total time-time dispersion and the preset dispersion threshold when the total time-time dispersion is greater than the preset dispersion threshold; and to adjust the preset temperature threshold based on the first time-time dispersion and the preset dispersion threshold when the first time-time dispersion is greater than the preset dispersion threshold; and to adjust the preset temperature threshold based on the second time-time dispersion and the preset dispersion threshold when the second time-time dispersion is greater than the preset dispersion threshold.

[0043] Compared with existing technologies, the advantages of this invention lie in its ability to promptly detect initial risks such as excessively high tank temperature or abnormal acidity by real-time acquisition of key parameters such as tank temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey precipitation rate, curd viscosity, and lactic acid formation rate. Furthermore, the system determines the type of anomaly by analyzing changes in lactic acid formation rate and curd viscosity, thereby calculating an anomaly index to adjust the stirring rate. Simultaneously, the adjustment results are corrected using the whey precipitation rate to ensure a reasonable ratio between lactic acid accumulation and curd formation, maintaining uniform fermentation. The system further automatically adjusts the temperature threshold based on fluctuations in the corrected stirring rate over a certain period, achieving a dynamic balance between temperature, pH value, lactic acid formation rate, and curd viscosity. This ensures stability of the fermentation process and controllable product quality, improves fermentation efficiency, reduces the risk of localized whey precipitation and excessive acidification, and effectively solves the problem of difficulty in timely identification and adjustment of fermentation anomalies due to single-parameter monitoring and empirical threshold judgments.

[0044] Furthermore, by setting up a comparison unit to monitor the tank temperature in real time and compare it with a preset temperature threshold, a suspected fermentation anomaly trigger result is immediately generated when the tank temperature exceeds the threshold, enabling an immediate response to temperature changes during fermentation. This mechanism utilizes the direct correlation between temperature and the metabolic rate of lactic acid bacteria and lactic acid production to ensure timely control measures are taken when the temperature rises abnormally, thereby maintaining the uniformity of the yogurt fermentation process and the stability of product quality. Simultaneously, it avoids pH deviation and increased whey separation caused by temperature fluctuations, ensuring the coordinated operation of the entire system under the influence of multiple parameters.

[0045] Furthermore, by analyzing the time series of pH changes and whey separation rates from the tank walls within a preset screening period, continuous abnormal trends can be identified, and an anomaly index can be calculated based on the combined changes of these two parameters to determine the actual anomaly. This method utilizes the close relationship between pH decreases and lactic acid production and protein coagulation, as well as the characteristic that whey separation rate reflects changes in curd structure, to achieve multidimensional monitoring of the fermentation process. By comprehensively considering the dynamic changes of these two key parameters, it is possible to accurately distinguish between transient fluctuations and genuine fermentation anomalies, providing a scientific basis for subsequent adjustments to stirring rate or temperature, thereby ensuring the texture, flavor, and stability of the yogurt.

[0046] Furthermore, by calculating and analyzing the rate of pH decrease and the rate of whey separation from the tank wall in real time, this system can identify persistent abnormal trends during yogurt fermentation. When the pH decreases rapidly and the whey separation rate increases significantly, it indicates that the yogurt is acidifying too quickly and the curd structure is unstable. The system can promptly capture this change, accurately reflecting the fermentation state of the yogurt, thus providing a reliable basis for subsequent stirring rate adjustments and temperature control, effectively improving fermentation uniformity and the texture stability of the final product.

[0047] Furthermore, by calculating and weighting the rate of pH decrease and the rate of whey separation in real time, this system can quantify the changing trends of these two key fermentation parameters into a joint anomaly index, enabling sensitive detection of fermentation process anomalies. This method reflects the interaction between the acidification rate and whey separation rate within the yogurt, thus providing a scientific basis for subsequent rate adjustments and ensuring the uniformity of the fermentation process and the stability of product quality.

[0048] Furthermore, by jointly analyzing the rate of increase in curd viscosity and the rate of lactic acid formation, this system can distinguish between three fermentation states: complex anomalies, coagulation anomalies, and acidification anomalies, achieving accurate identification of different anomaly types. During fermentation, curd viscosity reflects the degree of protein coagulation, while the rate of lactic acid formation reflects the acidification process; the trends of both reveal the state of fermentation kinetics. By setting reasonable thresholds, this system can promptly capture abnormal fermentation signals and provide targeted adjustment criteria based on different anomaly types, thereby effectively controlling fermentation quality and improving product consistency.

[0049] Furthermore, by simultaneously analyzing multiple parameters such as temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey precipitation rate, curd viscosity, and lactic acid formation rate, the combined impact of different types of anomalies is quantified into an anomaly index. This index can accurately reflect the changing trends during the fermentation process, and the stirring rate can be dynamically adjusted based on the anomaly index. This optimizes the coordination of lactic acid bacteria activity, lactic acid formation, and curd formation, thereby improving fermentation uniformity and product quality stability.

[0050] Furthermore, by calculating the fluctuation value of the whey separation rate on the tank wall, the instability of the whey separation process over a certain period of time can be reflected. When the separation rate fluctuates significantly, the correction module adjusts the stirring rate based on the relative deviation between the fluctuation level and the preset threshold, making the stirring more adaptable to the changes in the physical state inside the fermentation tank. This balances the rate of curd formation and lactic acid production, achieving dynamic and stable control of the fermentation process and improving the homogeneity and consistency of the final yogurt.

[0051] Furthermore, the preset temperature threshold is dynamically optimized through a threshold adjustment module, allowing for the assessment of fermentation process stability based on the number of corrections for different anomaly indices and their temporal distribution. When anomaly adjustments are frequent and concentrated, the system automatically raises the temperature threshold to reduce false alarms; when anomaly adjustments are infrequent or scattered, the threshold is maintained or moderately lowered to ensure sensitivity. This ensures that the temperature threshold remains coordinated with changes in key parameters such as tank temperature, pH value, and whey precipitation rate, achieving precise control and high stability of the fermentation process.

[0052] Furthermore, the temperature threshold can be finely controlled through the threshold adjustment unit, and the dispersion calculation subunit can be used to statistically analyze the time distribution of abnormal adjustment times, thereby determining the degree of concentration or dispersion of abnormal events. When the dispersion of the total time or a single time exceeds the preset threshold, the system automatically adjusts the temperature threshold to balance sensitivity and stability, ensuring that the adjustment of the temperature threshold matches the number of abnormal index corrections, the time of occurrence, and the fluctuations in tank temperature, pH value, and whey precipitation rate, thereby optimizing the overall stability of the fermentation process and product quality. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the control system of the yogurt fermentation device in this embodiment;

[0054] Figure 2 This embodiment generates a logic diagram for determining if a suspected fermentation abnormality has occurred.

[0055] Figure 3 This is a logic diagram for determining whether an actual abnormality has occurred in the determination unit of this embodiment;

[0056] Figure 4This is a logic diagram for determining the presence of an abnormal fermentation trend in the analysis subunit of this embodiment. Detailed Implementation

[0057] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0058] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0059] Please see Figure 1 As shown, this is a schematic diagram of the control system of the yogurt fermentation device in this embodiment. This embodiment provides a control system for a yogurt fermentation device, including:

[0060] The data acquisition module is used to collect data in real time on the temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey separation rate, curd viscosity, and lactic acid production rate inside the yogurt fermentation tank, which is running at a preset stirring rate.

[0061] A trigger generation module, which is connected to the acquisition module, is used to generate a triggering abnormality result corresponding to the occurrence of suspected fermentation abnormality based on the tank temperature and a preset temperature threshold.

[0062] The determination module is connected to the trigger generation module and the acquisition module respectively, and is used to determine the occurrence of actual abnormalities based on the pH value and the whey precipitation rate of the tank wall within a preset screening time, so as to obtain the abnormality result to be processed.

[0063] An identification module, which is connected to the judgment module and the acquisition module respectively, is used to identify the abnormal elements corresponding to the abnormal result to be processed based on the curd viscosity and the lactic acid generation rate.

[0064] A rate adjustment module, which is connected to the identification module and the acquisition module respectively, is used to determine the corresponding abnormal index based on the abnormal element, and to adjust the preset stirring rate according to the abnormal index to obtain the adjusted stirring rate;

[0065] A correction module, which is connected to the rate adjustment module, is used to correct the adjusted stirring rate based on the whey precipitation rate of the tank wall after the adjusted stirring rate is obtained, so as to obtain a corrected stirring rate.

[0066] A threshold adjustment module, which is connected to the correction module and the trigger generation module respectively, is used to adjust the preset temperature threshold according to the correction stirring rate within the preset threshold adjustment time.

[0067] In this embodiment, multiple sensors are deployed inside the yogurt fermentation tank to achieve real-time monitoring of various parameters: temperature is collected at different heights and areas of the tank using distributed thermocouples or PT100 temperature sensors; pH value is collected and calibrated in real time using an online pH electrode; stirring power is obtained using a current sensor or power meter connected to the stirring motor; dissolved oxygen content is measured using a dissolved oxygen electrode or optical DO sensor; tank wall adhesion rate is detected by a laser displacement sensor or ultrasonic ranging device to measure the thickness change of the dairy product on the tank wall; whey separation rate is obtained by a local flow velocity sensor combined with image or optical detection devices; curd viscosity is determined by an online rotary viscometer or vibratory viscosity sensor; and lactic acid formation rate is calculated by real-time collection of pH change rate combined with a lactic acid concentration sensor or optical refractometer. The signals collected by each sensor are filtered, corrected, and time-synchronized by the data processing unit of the acquisition module to achieve high-frequency, continuous, and stable parameter acquisition, providing a reliable data foundation for subsequent anomaly detection and control.

[0068] The preset stirring rate is the initial stirring speed of the fermentation tank under normal operation. It depends on the type of yogurt, the tank capacity, and the structure of the stirring blades, and is usually set between 30 rpm and 120 rpm. In this embodiment, it is set to 60 rpm, which can ensure uniform distribution of the emulsion and promote the activity of lactic acid bacteria. The preset temperature threshold is the upper or lower limit of the temperature used to trigger the judgment of suspected fermentation abnormalities. It depends on the requirements of the yogurt fermentation process and the tolerance of the strains, and is usually set between 37°C and 45°C. In this embodiment, it is set to 42°C, which can detect abnormal temperatures in the tank in time and ensure the stability of the fermentation process. The preset screening time is the time window used to determine actual abnormalities. It depends on the lactic acid production rate and the pH change rate, and is usually set between 10 minutes and 30 minutes. In this embodiment, it is set to 15 minutes, which can effectively filter out short-term fluctuation interference and accurately capture continuous abnormalities. The preset threshold adjustment time is the observation period used to monitor the adjustment effect and correct the threshold. It depends on the overall dynamic characteristics of the fermentation process, and is usually set between 30 minutes and 90 minutes. In this embodiment, it is set to 60 minutes, which can reasonably optimize the temperature threshold based on historical adjustment data and improve the fermentation control accuracy.

[0069] By real-time monitoring of key parameters such as tank temperature, pH, stirring power, dissolved oxygen content, tank wall adhesion rate, whey precipitation rate, curd viscosity, and lactic acid formation rate, the system can promptly detect initial risks such as excessively high tank temperature or abnormal acidity. Changes in lactic acid formation rate and curd viscosity are used to determine the type of anomaly, and an anomaly index is calculated to adjust the stirring rate. Simultaneously, the adjustment results are corrected using the whey precipitation rate to ensure a reasonable ratio between lactic acid accumulation and curd formation, maintaining uniform fermentation. Furthermore, the system automatically adjusts the temperature threshold based on fluctuations in the corrected stirring rate over a certain period, achieving a dynamic balance between temperature, pH, lactic acid formation rate, and curd viscosity. This ensures stability of the fermentation process and controllable product quality, improves fermentation efficiency, reduces the risk of localized whey precipitation and over-acidification, and effectively solves the problem of difficulty in timely identification and adjustment of fermentation anomalies due to single-parameter monitoring and experience-based threshold judgments.

[0070] Please see Figure 2 As shown, this is the logic diagram for determining the presence of suspected fermentation abnormalities by the generation unit in this embodiment. In this embodiment, the trigger generation module includes:

[0071] A comparison unit is used to compare the temperature inside the tank with a preset temperature threshold to obtain a temperature comparison result;

[0072] A generation unit, connected to the comparison unit, is used to determine a suspected fermentation abnormality when the temperature comparison result indicates that the temperature inside the tank is greater than the preset temperature threshold, and to generate the triggering abnormality result corresponding to the suspected fermentation abnormality.

[0073] By setting up a comparison unit to monitor the tank temperature in real time and compare it with a preset temperature threshold, a suspected fermentation anomaly trigger result is immediately generated when the tank temperature exceeds the threshold, enabling an immediate response to temperature changes during fermentation. This mechanism utilizes the direct correlation between temperature and the metabolic rate of lactic acid bacteria and lactic acid production to ensure timely control measures are taken when the temperature rises abnormally, thereby maintaining the uniformity of the yogurt fermentation process and the stability of product quality. It also avoids pH deviation and increased whey separation caused by temperature fluctuations, ensuring the coordinated operation of the entire system under the influence of multiple parameters.

[0074] Please see Figure 3 As shown, this is a determination logic diagram of the determination unit in this embodiment. In this embodiment, the determination module includes:

[0075] The analysis unit is used to perform time-series analysis on the pH value and the whey precipitation rate from the tank wall within a preset screening time to obtain continuous abnormal results.

[0076] An index determination unit, connected to the analysis unit, is used to determine a joint anomaly index based on the persistent anomaly results, according to the pH value and the whey precipitation rate from the tank wall.

[0077] The determination unit is used to determine the occurrence of the actual anomaly when the joint anomaly index is greater than the preset standard joint index, so as to obtain the result of the anomaly to be processed.

[0078] The preset standard combined index is the threshold for judging the combined abnormality of pH value and whey separation rate from tank wall. It depends on the yogurt variety, fermentation tank capacity and strain activity, and is usually set between 0.6 and 0.9. In this embodiment, it is set to 0.75, which can effectively distinguish between short-term fluctuations and continuous abnormalities, and ensure the accuracy of abnormality judgment.

[0079] By analyzing the time series of pH changes and whey separation rates from the tank walls within a preset screening period, a persistent abnormal trend can be identified. An anomaly index is calculated based on the combined changes of these two parameters to determine the actual anomaly. This method utilizes the close relationship between pH decreases and lactic acid production and protein coagulation, as well as the characteristic of whey separation rate reflecting changes in curd structure, to achieve multidimensional monitoring of the fermentation process. By comprehensively analyzing the dynamic changes of these two key parameters, it is possible to accurately distinguish between transient fluctuations and genuine fermentation anomalies, providing a scientific basis for subsequent adjustments to stirring rate or temperature, thereby ensuring the texture, flavor, and stability of the yogurt.

[0080] Please see Figure 4 As shown, this is the logic diagram for determining the presence of an abnormal fermentation trend in the analysis subunit of this embodiment. In this embodiment, the analysis unit includes:

[0081] The rate of change calculation subunit is used to calculate the rate of change of pH value during the continuous decrease period when the pH value continuously decreases within the preset screening time, and to obtain the pH decrease rate; and to calculate the rate of change of whey separation rate of tank wall during the continuous increase period when the whey separation rate of tank wall continuously increases within the preset screening time, and to obtain the whey separation rate change value.

[0082] An analysis subunit, connected to the rate of change calculation subunit, is used to determine the existence of a continuous abnormal fermentation trend within the preset screening time when the pH decrease rate is greater than a preset pH decrease rate threshold and the whey separation rate change value is greater than a preset rate change value threshold, so as to obtain the continuous abnormal result.

[0083] The preset rate change threshold is a critical value used to determine abnormal changes in whey separation rate. It depends on the type of yogurt, fermentation temperature, and tank characteristics, and is usually set between 0.2 g / (L·min) and 1.0 g / (L·min). In this embodiment, it is set to 0.5 g / (L·min), which can accurately distinguish between normal whey separation fluctuations and abnormal rapid separation trends.

[0084] By calculating and analyzing the rate of pH decrease and the rate of whey separation from the tank wall in real time, this system can identify persistent abnormal trends during yogurt fermentation. When the pH decreases rapidly and the whey separation rate increases significantly, it indicates that the yogurt is acidifying too quickly and the curd structure is unstable. The system can promptly capture this change, accurately reflecting the fermentation status of the yogurt, thus providing a reliable basis for subsequent stirring rate adjustments and temperature control, effectively improving fermentation uniformity and the texture stability of the final product.

[0085] Specifically, the index determination unit includes:

[0086] The rate calculation subunit is used to calculate the difference between the pH value at each moment during the continuous decreasing time period and the pH value at the initial moment to obtain several pH change rates, and to calculate the difference between the whey precipitation rate of the tank wall at each moment during the continuous increasing time period and the whey precipitation rate of the tank wall at the initial moment to obtain several precipitation change rates.

[0087] The index determination subunit is used to perform a weighted summation calculation on the average value of all pH change rates, a preset first weight, the average value of all precipitation change rates, and a preset second weight to obtain the joint anomaly index.

[0088] The first preset weight is used to adjust the influence of pH change rate on the joint anomaly index. It depends on acidification sensitivity and product target acidity, and is usually set between 0.3 and 0.7. In this embodiment, it is set to 0.5, which can balance the contribution of pH change to anomaly judgment and ensure that acidification trend is reasonably reflected. The second preset weight is used to adjust the influence of whey separation rate on the joint anomaly index. It depends on whey separation sensitivity and curd structure stability, and is usually set between 0.3 and 0.7. In this embodiment, it is set to 0.5, which can reasonably reflect the impact of whey separation on fermentation anomalies and ensure the comprehensiveness and reliability of the joint index.

[0089] By calculating and weighting the rate of pH decrease and the rate of whey separation in real time, this system can quantify the changing trends of these two key fermentation parameters into a joint anomaly index, enabling sensitive detection of fermentation process anomalies. This method reflects the interaction between the acidification rate and whey separation rate within the yogurt, providing a scientific basis for subsequent rate adjustments and ensuring the uniformity of the fermentation process and the stability of product quality.

[0090] Specifically, the identification module includes:

[0091] The feature extraction unit is used to extract the growth rate of the curd viscosity within the same preset screening time to obtain the viscosity growth rate, and to extract the average value of the lactic acid generation rate within the same preset screening time to obtain the average generation rate.

[0092] An identification unit, connected to the feature extraction unit, is used to identify the abnormal element as a composite abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold; to identify the abnormal element as a solidification abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is greater than a preset average generation threshold; and to identify the abnormal element as an acidification abnormality when the viscosity growth rate is less than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold.

[0093] The preset viscosity growth threshold is a reference value used to determine abnormal curd coagulation rate. It depends on the fermentation strain and dairy product formulation used, and is usually set between 0.5 Pa / s and 2.0 Pa / s. In this embodiment, it is set to 1.2 Pa / s, which can promptly identify abnormal curd formation rates. The preset average generation threshold is a reference value used to determine abnormal lactic acid generation rate. It depends on the fermentation temperature and lactic acid bacteria activity, and is usually set between 0.8 mmol / L·min and 3.0 mmol / L·min. In this embodiment, it is set to 1.5 mmol / L·min, which can effectively monitor the acidification process and prevent acidification that is too fast or too slow.

[0094] By jointly analyzing the rate of increase in curd viscosity and the rate of lactic acid formation, this system can distinguish between three fermentation states: complex anomalies, coagulation anomalies, and acidification anomalies, achieving accurate identification of different anomaly types. During fermentation, curd viscosity reflects the degree of protein coagulation, while the rate of lactic acid formation reflects the acidification process; the trends of both reveal the state of fermentation kinetics. By setting reasonable thresholds, this system can promptly capture abnormal fermentation signals and provide targeted adjustment criteria based on different anomaly types, thereby effectively controlling fermentation quality and improving product consistency.

[0095] Specifically, the rate adjustment module includes:

[0096] The first abnormality index calculation unit is used to calculate the abnormality index based on the tank temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, tank wall whey precipitation rate, curd viscosity and lactic acid generation rate within the same preset screening time when the abnormal element is the composite abnormality.

[0097] The second calculation unit for the abnormality index is used to calculate the abnormality index based on the coagulation viscosity, the stirring power, and the tank wall adhesion rate within the same preset screening time when the abnormal element is the coagulation abnormality or the acidification abnormality.

[0098] A rate adjustment unit, which is connected to the first abnormality index calculation unit and the second abnormality index calculation unit respectively, is used to adjust the preset stirring rate according to the abnormality index and the preset abnormality index threshold when the abnormality index is greater than the preset abnormality index threshold, so as to obtain the adjusted stirring rate, wherein V'=V×[1-k1×(Y-Y0 / Y0)], V' is the adjusted stirring rate, V is the preset stirring rate, k1 is the preset rate adjustment coefficient, Y is the abnormality index, and Y0 is the preset abnormality index threshold.

[0099] The preset rate adjustment coefficient is a proportional coefficient used to control the adjustment range of the stirring rate. It depends on the dynamic response characteristics of the fermenter stirring system and the sensitivity of yogurt fermentation to stirring. It is usually set between 0.1 and 0.5. In this embodiment, it is set to 0.2, which can achieve a rapid and stable response to abnormal index changes and avoid causing excessive disturbance to the fermentation process.

[0100] In this embodiment, the process of the first anomaly index calculation unit calculating the anomaly index includes calculating the average value of each parameter and performing a weighted summation calculation by combining preset first weighted anomaly recombinations to finally obtain the anomaly index; the process of the first anomaly index calculation unit calculating the anomaly index includes calculating the average value of each parameter and performing a weighted summation calculation by combining preset second weighted anomaly recombinations to finally obtain the anomaly index.

[0101] The preset first-weighted anomaly recombination is a set of coefficients used to weight the parameters involved in the composite anomaly. It depends on the sensitivity of each parameter to fermentation equilibrium and lactic acid production rate, and is typically set between 0.1 and 1.0. In this embodiment, the coefficients are set sequentially as {0.3, 0.2, 0.15, 0.1, 0.1, 0.1, 0.05} for the following parameters: tank temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey precipitation rate from the tank wall, curd viscosity, and lactic acid production rate. This arrangement reasonably reflects the values ​​of each parameter. The contribution to the anomaly index improves the accuracy of composite anomaly judgment; the preset second weighted anomaly recombination is a set of coefficients used to weight the parameters involved in coagulation anomalies or acidification anomalies. It depends on the degree of influence of curd viscosity, stirring power and tank wall adhesion rate on the anomaly trend, and is usually set between 0.1 and 1.0. In this embodiment, it is set to {0.5, 0.3, 0.2} in the order of curd viscosity, stirring power and tank wall adhesion rate, which can effectively highlight the influence of key parameters on the anomaly index, thereby accurately guiding the adjustment of stirring rate.

[0102] By simultaneously analyzing multiple parameters such as temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey precipitation rate, curd viscosity, and lactic acid formation rate, the combined impact of different types of anomalies is quantified into an anomaly index. This index can accurately reflect the changing trends during the fermentation process and dynamically adjust the stirring rate based on the anomaly index. This optimizes the coordination of lactic acid bacteria activity, lactic acid formation, and curd formation, thereby improving fermentation uniformity and product quality stability.

[0103] Specifically, the correction module includes:

[0104] The velocity fluctuation value calculation unit is used to calculate the standard deviation of the whey precipitation rate of all the tank walls within a preset correction time to obtain the precipitation velocity fluctuation value.

[0105] The correction unit is used to correct the adjusted stirring rate based on the relative deviation between the speed fluctuation value and the preset speed fluctuation threshold and a preset correction coefficient when the speed fluctuation value is greater than the preset speed fluctuation threshold, so as to obtain the corrected stirring rate, where V”=V'×[1-k2×(P-P0) / P0], V” is the corrected stirring rate, k2 is the preset correction coefficient, P is the speed fluctuation value, and P0 is the preset speed fluctuation threshold.

[0106] The preset correction time is the length of the time window used to calculate the fluctuation of whey separation rate. It depends on the fermenter capacity and stirring uniformity, and is usually set between 5 and 20 minutes. In this embodiment, it is set to 10 minutes to capture rate fluctuations during fermentation in a timely manner. The preset speed fluctuation threshold is a reference value for judging whether the whey separation rate fluctuates abnormally. It depends on the characteristics of the yogurt formula and the requirements of the fermentation process, and is usually set between 0.01 g / (L·min) and 0.05 g / (L·min). In this embodiment, it is set to 0.03 g / (L·min) to distinguish between normal fluctuations and abnormal fluctuations that need adjustment. The preset correction coefficient is a proportional coefficient used to calculate the amplitude of stirring rate correction. It depends on the stirring kinetics characteristics of the fermenter, and is usually set between 0.1 and 0.5. In this embodiment, it is set to 0.2 to achieve smooth and effective stirring rate correction and avoid causing excessive disturbance to the fermentation process.

[0107] By calculating the fluctuation value of the whey separation rate on the tank wall, the instability of the whey separation process over a certain period of time can be reflected. When the separation rate fluctuates significantly, the correction module adjusts the stirring rate based on the relative deviation between the fluctuation level and the preset threshold, making the stirring more adaptable to the changes in the physical state inside the fermentation tank. This balances the rate of curd formation and lactic acid production, achieving dynamic and stable control of the fermentation process and improving the homogeneity and consistency of the final yogurt.

[0108] Specifically, the threshold adjustment module includes:

[0109] The number of times acquisition unit is used to acquire the number of times and timestamps of the correction of the abnormal index calculated by the first calculation unit of the abnormal index within the preset threshold adjustment time to obtain the first number and several first moments, and to acquire the number of times and timestamps of the correction of the abnormal index calculated by the second calculation unit of the abnormal index within the preset threshold adjustment time to obtain the second number and several second moments.

[0110] A threshold adjustment unit, connected to the count acquisition unit, is used to adjust the preset temperature threshold based on the first count, the first time, the second count, and the second time.

[0111] The system dynamically optimizes preset temperature thresholds through a threshold adjustment module, assessing the stability of the fermentation process based on the number of corrections for different anomaly indices and their temporal distribution. When anomaly adjustments are frequent and concentrated, the system automatically raises the temperature threshold to reduce false alarms; when anomaly adjustments are infrequent or scattered, the threshold is maintained or moderately lowered to ensure sensitivity. This ensures that the temperature threshold remains coordinated with changes in key parameters such as tank temperature, pH value, and whey precipitation rate, achieving precise control and high stability of the fermentation process.

[0112] Specifically, the threshold adjustment unit includes:

[0113] The dispersion calculation subunit is used to calculate the standard deviation of the difference between the first time and the second time and the initial time when both the first number and the second number are greater than a preset number threshold, to obtain the total time dispersion; and to calculate the standard deviation of the difference between all the first time and the initial time when the first number is greater than the preset number threshold and the second number is less than or equal to the preset number threshold, to obtain the first time dispersion; and to calculate the standard deviation of the difference between all the second time and the initial time when the second number is greater than the preset number threshold and the first number is less than or equal to the preset number threshold, to obtain the second time dispersion.

[0114] A threshold adjustment subunit, connected to the dispersion calculation subunit, is used to adjust the preset temperature threshold according to the total time dispersion and the preset dispersion threshold when the total time dispersion is greater than the preset dispersion threshold, wherein T'=T×[1-k3×(W-W0) / W0], T' is the adjusted preset temperature threshold, T is the original preset temperature threshold, k3 is the preset threshold adjustment coefficient, W is the total time dispersion, and W0 is the preset dispersion threshold; and, when the first time dispersion is greater than the preset dispersion threshold, the preset temperature threshold is adjusted according to the first time dispersion and the preset dispersion threshold, wherein T'=T×[1-k3×(W1-W0) / W0], W1 is the first time dispersion; and, when the second time dispersion is greater than the preset dispersion threshold, the preset temperature threshold is adjusted according to the second time dispersion and the preset dispersion threshold, wherein T'=T×[1-k3×(W2-W0) / W0], W2 is the first time dispersion.

[0115] The preset frequency threshold is used to determine the frequency of abnormal adjustments. It depends on the fluctuation characteristics and control sensitivity of the yogurt fermentation process and is usually set between 3 and 10 times. In this embodiment, it is set to 5 times, which can effectively distinguish between occasional fluctuations and continuous abnormalities, ensuring the reliability of threshold adjustment. The preset dispersion threshold is used to determine the degree of concentration of the time distribution of abnormal adjustments. It depends on the stability of the temperature fluctuations in the fermenter and whey separation and is usually set between 0.5 and 2 hours. In this embodiment, it is set to 1 hour, which can accurately reflect the dispersion or concentration characteristics of abnormal events, thereby optimizing the temperature threshold adjustment strategy. The preset threshold adjustment coefficient is used to adjust the proportional coefficient of the temperature threshold response dispersion change. It depends on the response sensitivity of the fermenter temperature control system and the characteristics of the dairy product process and is usually set between 0.01 and 0.2. In this embodiment, it is set to 0.05, which can moderately reduce the preset temperature threshold when the temperature fluctuation is large, improving the timeliness of abnormal response and the stability of the fermentation process.

[0116] The temperature threshold can be finely controlled by the threshold adjustment unit, and the dispersion calculation subunit can be used to statistically analyze the time distribution of abnormal adjustment times to determine the concentration or dispersion of abnormal events. When the dispersion of the total time or a single time exceeds the preset threshold, the system automatically adjusts the temperature threshold to balance sensitivity and stability, ensuring that the temperature threshold adjustment matches the number of abnormal index corrections, the time of occurrence, and the fluctuations in tank temperature, pH value, and whey precipitation rate, thereby optimizing the overall stability of the fermentation process and product quality.

[0117] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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.

Claims

1. A control system for a yogurt fermentation device, characterized in that, include: The data acquisition module is used to collect data in real time on the temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, whey separation rate, curd viscosity, and lactic acid production rate inside the yogurt fermentation tank, which is running at a preset stirring rate. A trigger generation module, which is connected to the acquisition module, is used to generate a triggering abnormality result corresponding to the occurrence of suspected fermentation abnormality based on the tank temperature and a preset temperature threshold. The determination module is connected to the trigger generation module and the acquisition module respectively, and is used to determine the occurrence of actual abnormalities based on the pH value and the whey precipitation rate of the tank wall within a preset screening time, so as to obtain the abnormality result to be processed. An identification module, which is connected to the judgment module and the acquisition module respectively, is used to identify the abnormal elements corresponding to the abnormal result to be processed based on the curd viscosity and the lactic acid generation rate. A rate adjustment module, which is connected to the identification module and the acquisition module respectively, is used to determine the corresponding abnormal index based on the abnormal element, and to adjust the preset stirring rate according to the abnormal index to obtain the adjusted stirring rate; A correction module, which is connected to the rate adjustment module, is used to correct the adjusted stirring rate based on the whey precipitation rate of the tank wall after the adjusted stirring rate is obtained, so as to obtain a corrected stirring rate. A threshold adjustment module, which is connected to the correction module and the trigger generation module respectively, is used to adjust the preset temperature threshold according to the correction stirring rate within the preset threshold adjustment time.

2. The control system of the yogurt fermentation device according to claim 1, characterized in that, The trigger generation module includes: A comparison unit is used to compare the temperature inside the tank with a preset temperature threshold to obtain a temperature comparison result; A generation unit, connected to the comparison unit, is used to determine a suspected fermentation abnormality when the temperature comparison result indicates that the temperature inside the tank is greater than the preset temperature threshold, and to generate the triggering abnormality result corresponding to the suspected fermentation abnormality.

3. The control system of the yogurt fermentation device according to claim 2, characterized in that, The determination module includes: The analysis unit is used to perform time-series analysis on the pH value and the whey precipitation rate from the tank wall within a preset screening time to obtain continuous abnormal results. An index determination unit, connected to the analysis unit, is used to determine a joint anomaly index based on the persistent anomaly results, according to the pH value and the whey precipitation rate from the tank wall. The determination unit is used to determine the occurrence of the actual anomaly when the joint anomaly index is greater than the preset standard joint index, so as to obtain the result of the anomaly to be processed.

4. The control system of the yogurt fermentation device according to claim 3, characterized in that, The analysis unit includes: The rate of change calculation subunit is used to calculate the rate of change of pH value during the continuous decrease period when the pH value continuously decreases within the preset screening time, and to obtain the pH decrease rate; and to calculate the rate of change of whey separation rate of tank wall during the continuous increase period when the whey separation rate of tank wall continuously increases within the preset screening time, and to obtain the whey separation rate change value. An analysis subunit, connected to the rate of change calculation subunit, is used to determine the existence of a continuous abnormal fermentation trend within the preset screening time when the pH decrease rate is greater than a preset pH decrease rate threshold and the whey separation rate change value is greater than a preset rate change value threshold, so as to obtain the continuous abnormal result.

5. The control system of the yogurt fermentation device according to claim 4, characterized in that, The index determination unit includes: The rate calculation subunit is used to calculate the difference between the pH value at each moment during the continuous decreasing time period and the pH value at the initial moment to obtain several pH change rates, and to calculate the difference between the whey precipitation rate of the tank wall at each moment during the continuous increasing time period and the whey precipitation rate of the tank wall at the initial moment to obtain several precipitation change rates. The index determination subunit is used to perform a weighted summation calculation on the average value of all pH change rates, a preset first weight, the average value of all precipitation change rates, and a preset second weight to obtain the joint anomaly index.

6. The control system of the yogurt fermentation apparatus according to claim 5, characterized in that, The identification module includes: The feature extraction unit is used to extract the growth rate of the curd viscosity within the same preset screening time to obtain the viscosity growth rate, and to extract the average value of the lactic acid generation rate within the same preset screening time to obtain the average generation rate. An identification unit, connected to the feature extraction unit, is used to identify the abnormal element as a composite abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold; to identify the abnormal element as a solidification abnormality when the viscosity growth rate is greater than a preset viscosity growth threshold and the average generation rate is greater than a preset average generation threshold; and to identify the abnormal element as an acidification abnormality when the viscosity growth rate is less than a preset viscosity growth threshold and the average generation rate is less than a preset average generation threshold.

7. The control system of the yogurt fermentation apparatus according to claim 6, characterized in that, The rate adjustment module includes: The first abnormality index calculation unit is used to calculate the abnormality index based on the tank temperature, pH value, stirring power, dissolved oxygen content, tank wall adhesion rate, tank wall whey precipitation rate, curd viscosity and lactic acid generation rate within the same preset screening time when the abnormal element is the composite abnormality. The second calculation unit for the abnormality index is used to calculate the abnormality index based on the coagulation viscosity, the stirring power, and the tank wall adhesion rate within the same preset screening time when the abnormal element is the coagulation abnormality or the acidification abnormality. A rate adjustment unit is connected to the first abnormality index calculation unit and the second abnormality index calculation unit, respectively, and is used to adjust the preset stirring rate according to the abnormality index and the preset abnormality index threshold when the abnormality index is greater than the preset abnormality index threshold, so as to obtain the adjusted stirring rate.

8. The control system of the yogurt fermentation apparatus according to claim 7, characterized in that, The correction module includes: The velocity fluctuation value calculation unit is used to calculate the standard deviation of the whey precipitation rate of all the tank walls within a preset correction time to obtain the precipitation velocity fluctuation value. The correction unit is used to correct the adjusted stirring rate based on the relative deviation between the speed fluctuation value and the preset speed fluctuation threshold and a preset correction coefficient when the speed fluctuation value is greater than the preset speed fluctuation threshold, so as to obtain the corrected stirring rate.

9. The control system of the yogurt fermentation apparatus according to claim 8, characterized in that, The threshold adjustment module includes: The number of times acquisition unit is used to acquire the number of times and timestamps of the correction of the abnormal index calculated by the first calculation unit of the abnormal index within the preset threshold adjustment time to obtain the first number and several first moments, and to acquire the number of times and timestamps of the correction of the abnormal index calculated by the second calculation unit of the abnormal index within the preset threshold adjustment time to obtain the second number and several second moments. A threshold adjustment unit, connected to the count acquisition unit, is used to adjust the preset temperature threshold based on the first count, the first time, the second count, and the second time.

10. The control system of the yogurt fermentation apparatus according to claim 9, characterized in that, The threshold adjustment unit includes: The dispersion calculation subunit is used to calculate the standard deviation of the difference between the first time and the second time and the initial time when both the first number and the second number are greater than a preset number threshold, to obtain the total time dispersion; and to calculate the standard deviation of the difference between all the first time and the initial time when the first number is greater than the preset number threshold and the second number is less than or equal to the preset number threshold, to obtain the first time dispersion; and to calculate the standard deviation of the difference between all the second time and the initial time when the second number is greater than the preset number threshold and the first number is less than or equal to the preset number threshold, to obtain the second time dispersion. A threshold adjustment subunit, connected to the dispersion calculation subunit, is used to adjust the preset temperature threshold based on the total time-time dispersion and the preset dispersion threshold when the total time-time dispersion is greater than the preset dispersion threshold; and to adjust the preset temperature threshold based on the first time-time dispersion and the preset dispersion threshold when the first time-time dispersion is greater than the preset dispersion threshold; and to adjust the preset temperature threshold based on the second time-time dispersion and the preset dispersion threshold when the second time-time dispersion is greater than the preset dispersion threshold.

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