Moisture control method and system for production process of cassava starch balls

Abstract

The invention provides a moisture control method and system for a cassava starch ball production process, and relates to the technical field of food drying. Initial moisture content of cassava starch ball samples is determined, a multi-stage drying method is adopted, and the drying process is divided into three stages of pre-drying, main drying and post-drying; a low-temperature hot air circulation dryer, a high-temperature hot air circulation dryer and a microwave dryer are adopted for treatment. In each stage, the target drying temperature and humidity are set, the temperature and humidity of the sample are monitored in real time, and accurate adjustment is carried out through a PID controller so as to ensure that the moisture content reaches the expected target. And finally, randomly extracting a sample, detecting the moisture content, calculating the qualified rate, and adjusting the proportionality coefficient of each drying stage according to the size relationship between the qualified rate and a qualified threshold value. According to the method, the drying process is finely managed, so that the quality and the consistency of the cassava starch balls are improved.

Description

Technical Field

[0001] The invention relates to the technical field of food drying, and in particular to a moisture control method and system for a cassava starch dumpling production process. Background Art

[0002] As a popular food, the control of moisture content in the production process of cassava starch dumplings is crucial. Traditional cassava starch dumpling drying methods usually use static drying or single temperature drying, which makes it difficult to achieve uniform and accurate moisture control and cannot meet the refined management and adjustment required at different stages, resulting in uneven quality of the final product, which has a serious impact on subsequent processing and consumption. Therefore, how to ensure that the moisture content of cassava starch dumplings reaches the ideal range through effective moisture control methods has become a technical problem that needs to be solved in the production process.

[0003] In the prior art, publication number CN112034809A discloses a starch moisture control method and system: pre-establishing a moisture prediction control model, obtaining a drying temperature corresponding to a target moisture value, drying the wet starch by the drying temperature, obtaining the moisture of the starch after drying, and judging whether the moisture of the starch after drying meets the target moisture value. If not, adjusting the drying temperature.

[0004] The main problems with the above method are: after the starch is dried, it is judged whether the target moisture value is met, and then the temperature is adjusted, which has a reaction lag, may cause over-drying or under-drying, and make the moisture control not precise enough; it relies on a pre-set moisture prediction model, and does not respond enough to environmental changes, resulting in unstable drying effect, while limiting the scalability and robustness of the system.

[0005] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0006] The object of the present invention is to provide a method and system for controlling moisture in a cassava starch dumpling production process, so as to solve the problems raised in the above-mentioned background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A moisture control method for a cassava starch dumpling production process, comprising the following specific steps:

[0009] Step 1: Select a certain mass of cassava starch ball samples and put them into an oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content;

[0010] Step 2: Based on multi-stage drying, the drying stages of cassava starch balls are divided into pre-drying, main drying and post-drying, and different target drying temperatures and target drying humidity are set in each stage;

[0011] Step 3: In the pre-drying stage, a low-temperature hot air circulation dryer is used, a target pre-drying temperature, a target pre-drying humidity and a pre-drying time are set, and the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage are monitored in real time, and a pre-drying temperature deviation is generated according to the deviation between the real-time temperature and the target pre-drying temperature, and a pre-drying humidity deviation is generated according to the deviation between the real-time humidity and the target pre-drying humidity, and based on the pre-drying temperature deviation and the pre-drying humidity deviation, the pre-drying temperature and the pre-drying humidity are adjusted by a PID controller to generate the moisture content after pre-drying;

[0012] Step 4: In the main drying stage, a high-temperature hot air circulation dryer is used, a target main drying temperature, a target main drying humidity and a main drying time are set, and the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage are monitored in real time. A main drying temperature deviation is generated according to the deviation between the real-time temperature and the target main drying temperature, and a main drying humidity deviation is generated according to the deviation between the real-time humidity and the target main drying humidity. Based on the main drying temperature deviation and the main drying humidity deviation, the main drying temperature and the main drying humidity are adjusted by a PID controller to generate the moisture content after the main drying;

[0013] Step 5: In the post-drying stage, a microwave dryer is used to set a target post-drying temperature, a target post-drying humidity and a post-drying time, and the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage are monitored in real time, and a post-drying temperature deviation is generated according to a deviation between the real-time temperature and the target post-drying temperature, and a post-drying humidity deviation is generated according to a deviation between the real-time humidity and the target post-drying humidity, and based on the post-drying temperature deviation and the post-drying humidity deviation, the post-drying temperature and the post-drying humidity are adjusted by a PID controller to generate the moisture content after post-drying;

[0014] Step 6: After the multi-stage drying is completed, a certain number of samples are randomly selected from the dried cassava starch balls, the moisture content of the selected cassava starch ball samples is detected, the number of cassava starch ball samples within the target moisture content range is calculated, and the qualified rate is generated;

[0015] Step 7: Preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, reduce the proportional coefficient; when the pass rate is less than the pass rate threshold, increase the proportional coefficient.

[0016] Further, the formula for generating the initial moisture content is:

[0017]

[0018] Where W0 represents the initial moisture content, M0 represents the mass of the cassava sample before drying, and M g Indicates the mass of cassava samples after drying.

[0019] Furthermore, the target drying temperature of each drying stage is as follows:

[0020] T b >T c >T a

[0021] Among them, T b represents the target main drying temperature, T c represents the target post-drying temperature, T a Indicates the target pre-drying temperature;

[0022] The target drying humidity in each drying stage is as follows:

[0023] H a >H b >H c

[0024] Among them, H a Indicates the target pre-drying humidity, H b Indicates the target main drying humidity, H c Indicates the target post-drying humidity.

[0025] Furthermore, the formula for adjusting the pre-drying temperature and pre-drying humidity by the PID controller is:

[0026]

[0027] in, represents the pre-drying temperature deviation, t1 represents the pre-drying time variable, T a represents the target pre-drying temperature, T1(t1) represents the real-time temperature during the pre-drying stage, Indicates the pre-drying humidity deviation, H a represents the target pre-drying humidity, H1(t1) represents the real-time humidity during the pre-drying stage, Indicates the pre-drying temperature control output, represents the pre-drying ratio coefficient, represents the pre-drying integral coefficient, represents the pre-drying differential coefficient, Indicates the pre-drying humidity control output;

[0028] The formula for generating the moisture content after pre-drying is:

[0029] WY =W0-△W Y

[0030] Among them, W Y represents the moisture content after pre-drying, W0 represents the initial moisture content, △W Y Indicates the moisture content reduced during the pre-drying stage.

[0031] Furthermore, the formula for adjusting the main drying temperature and the main drying humidity by the PID controller is:

[0032]

[0033] in, represents the main drying temperature deviation, t2 represents the main drying time variable, T b represents the target main drying temperature, T2(t2) represents the real-time temperature during the main drying stage, Indicates the main drying humidity deviation, H b represents the target main drying humidity, H2(t2) represents the real-time humidity in the main drying stage, Indicates the main drying temperature control output, represents the main drying ratio coefficient, represents the main drying integral coefficient, represents the post-drying differential coefficient, Indicates post-drying humidity control output;

[0034] The formula used to generate the moisture content after main drying is:

[0035] W Z =W Y -△W Z

[0036] Among them, W Z Indicates the moisture content after main drying, W Y Indicates the moisture content after pre-drying, △W Z Indicates the moisture content reduced during the main drying phase.

[0037] Furthermore, the formula for adjusting the post-drying temperature and post-drying humidity by the PID controller is:

[0038]

[0039] in, represents the post-drying temperature deviation, t3 represents the post-drying time variable, T c represents the target post-drying temperature, T3(t3) represents the real-time temperature in the post-drying stage, Indicates the post-drying humidity deviation, H crepresents the target post-drying humidity, H3(t3) represents the real-time humidity in the post-drying stage, Indicates the post-drying temperature control output, represents the post-drying ratio coefficient, represents the post-drying integral coefficient, represents the post-drying differential coefficient, Indicates post-drying humidity control output;

[0040] The moisture content after drying after generation is based on the formula:

[0041] W B =W Z -△W B

[0042] Among them, W B Indicates the moisture content after post-drying, W z Indicates the moisture content after main drying, △W B Indicates the reduced moisture content during the post-drying stage.

[0043] Furthermore, the formula for generating the pass rate is:

[0044]

[0045] Among them, R represents the qualified rate, N represents the number of cassava starch ball samples taken, and n represents the number of samples among the cassava starch ball samples taken whose moisture content is within the target moisture content range.

[0046] Furthermore, the formula for adjusting the proportional coefficient of the PID controller in each drying stage is:

[0047] The adjustment formula for the pre-drying stage is:

[0048]

[0049] in, Indicates the pre-drying ratio coefficient after adjustment, represents the pre-drying ratio coefficient, R represents the qualified rate, R0 represents the qualified rate threshold, δ1 represents the pre-drying adjustment index, -1≤δ1≤1, and when R>R0, δ1<0, when R<R0, δ1>0;

[0050] The adjustment formula for the main drying stage is:

[0051]

[0052] in, Indicates the main drying ratio coefficient after adjustment, represents the main drying ratio coefficient, δ2 represents the main drying adjustment index, -1≤δ2≤1, and when R>R0, δ2<0, when R<R0, δ2>0;

[0053] The adjustment formula for the post-drying stage is:

[0054]

[0055] in, Represents the post-drying ratio coefficient after adjustment, represents the post-drying proportional coefficient, δ3 represents the post-drying adjustment index, -1≤δ3≤1, and when R>R0, δ3<0, when R<R0, δ3>0.

[0056] The present invention also provides a moisture control system for a cassava starch dumpling production process, wherein the system is used to implement the moisture control method for the cassava starch dumpling production process, specifically comprising:

[0057] The moisture detection module is used to select a certain mass of cassava starch ball samples and put them into the oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content;

[0058] The drying classification module is used to divide the drying stages of cassava starch balls into pre-drying, main drying and post-drying based on multi-stage drying, and set different target drying temperatures and target drying humidity in each stage;

[0059] A pre-drying module is used to use a low-temperature hot air circulation dryer in the pre-drying stage, set a target pre-drying temperature, a target pre-drying humidity and a pre-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage in real time, generate a pre-drying temperature deviation according to the deviation between the real-time temperature and the target pre-drying temperature, generate a pre-drying humidity deviation according to the deviation between the real-time humidity and the target pre-drying humidity, and adjust the pre-drying temperature and pre-drying humidity through a PID controller based on the pre-drying temperature deviation and the pre-drying humidity deviation to generate the moisture content after pre-drying;

[0060] A main drying module is used to use a high-temperature hot air circulation dryer in the main drying stage, set a target main drying temperature, a target main drying humidity and a main drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage in real time, generate a main drying temperature deviation according to the deviation between the real-time temperature and the target main drying temperature, generate a main drying humidity deviation according to the deviation between the real-time humidity and the target main drying humidity, and adjust the main drying temperature and the main drying humidity through a PID controller based on the main drying temperature deviation and the main drying humidity deviation to generate the moisture content after the main drying;

[0061] A post-drying module is used to use a microwave dryer in the post-drying stage to set a target post-drying temperature, a target post-drying humidity and a post-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage in real time, generate a post-drying temperature deviation according to the deviation between the real-time temperature and the target post-drying temperature, generate a post-drying humidity deviation according to the deviation between the real-time humidity and the target post-drying humidity, and adjust the post-drying temperature and the post-drying humidity through a PID controller based on the post-drying temperature deviation and the post-drying humidity deviation to generate the moisture content after post-drying;

[0062] The effect evaluation module is used to randomly extract a certain number of samples from the dried cassava starch balls after the multi-stage drying is completed, detect the moisture content of the extracted cassava starch ball samples, calculate the number of cassava starch ball samples within the target moisture content range, and generate a qualified rate;

[0063] The adjustment feedback module is used to preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the size relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, the proportional coefficient is reduced, and when the pass rate is less than the pass rate threshold, the proportional coefficient is increased.

[0064] Compared with the prior art, the present invention has the following beneficial effects:

[0065] The present invention is based on a multi-stage drying method, and the drying process of cassava starch balls is divided into three stages: pre-drying, main drying and post-drying, and different target drying temperatures and target drying humidity are set in each stage. According to different moisture states and sample material characteristics, more suitable and efficient drying conditions can be respectively adopted. Through refined hierarchical control, it is ensured that the drying process of each drying stage is carried out under optimal conditions, thereby improving the accuracy and consistency of moisture control.

[0066] The present invention can also detect deviations in time during the multi-stage drying process by real-time monitoring of the temperature and humidity of the sample and comparing them with the target values, and dynamically adjust the deviations through the PID controller, and predict the changing trends of the temperature and humidity, so that certain measures can be taken before the deviation occurs, so that the system can respond quickly to dynamic changes, reduce temperature and humidity fluctuations, and ensure a smooth and efficient drying process; finally, the moisture content of the dried cassava starch balls is detected by random sampling, and it is judged whether the moisture control reaches the expected goal based on this, so that the overall drying effect can be effectively evaluated, and direct feedback of the drying process can be obtained, which promotes the continuous optimization and improvement of the drying process parameters and improves the applicability and expansibility of the scheme; and the proportional coefficient of the PID controller of each drying stage is adjusted in real time according to the qualified rate, and the sensitivity of the PID controller to the current temperature and humidity errors can be flexibly adjusted, so as to more accurately control the drying process and make the moisture content of the product more stably close to the target value. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] Figure 1 This is a schematic diagram of a method flow of an embodiment of the present invention;

[0068] Figure 2 Schematic diagram of system modules according to an embodiment of the present invention. DETAILED DESCRIPTION

[0069] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0070] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0071] Example:

[0072] See also Figure 1 , the present invention provides a technical solution:

[0073] A moisture control method for a cassava starch dumpling production process, comprising the following specific steps:

[0074] Step 1: Select a certain mass of cassava starch ball samples and put them into an oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content;

[0075] In this embodiment, the formula for generating the initial moisture content is:

[0076]

[0077] Where W0 represents the initial moisture content, M0 represents the mass of the cassava sample before drying, and M g Indicates the mass of cassava samples after drying.

[0078] Step 2: Based on multi-stage drying, the drying stages of cassava starch balls are divided into pre-drying, main drying and post-drying, and different target drying temperatures and target drying humidity are set in each stage;

[0079] In this embodiment, the target drying temperature in each drying stage is as follows:

[0080] T b >T c >T a

[0081] Among them, T b represents the target main drying temperature, T c represents the target post-drying temperature, T a Indicates the target pre-drying temperature;

[0082] The target drying humidity in each drying stage is as follows:

[0083] H a >H b >H c

[0084] Among them, H a Indicates the target pre-drying humidity, H b Indicates the target main drying humidity, H c Indicates the target post-drying humidity.

[0085] In the pre-drying stage, the goal is to remove surface moisture. Lower temperature and higher humidity can ensure that moisture evaporates from the surface of the tapioca starch dumplings without heating too quickly, avoiding the outer layer from drying too quickly and making it difficult to remove moisture from the inner layer. At the same time, a higher humidity environment helps to reduce the evaporation rate of moisture, relieve the drying stress inside the dumplings, and protect the structure. Therefore, the target pre-drying temperature is set at 35°C, and the target pre-drying humidity is set at 75%.

[0086] In the main drying stage, the goal is to quickly remove the moisture inside the dumplings. On the one hand, it is necessary to effectively accelerate the evaporation of moisture and ensure that the moisture in the dumplings can be quickly taken away to avoid moisture retention or re-absorption inside the dumplings. Therefore, the target main drying temperature is set at 65°C and the target main drying humidity is set at 30%.

[0087] In the post-drying stage, the goal is to fine-tune the moisture content to achieve the final required level. On the one hand, a stable drying environment should be provided to avoid over-drying or quality loss, and the moisture removal rate should be moderate. Therefore, the target post-drying temperature is set at 50°C and the target post-drying humidity is set at 20%.

[0088] Step 3: In the pre-drying stage, a low-temperature hot air circulation dryer is used to set a target pre-drying temperature, a target pre-drying humidity and a pre-drying time, and the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage are monitored in real time, and a pre-drying temperature deviation and a pre-drying humidity deviation are generated according to the deviation between the real-time temperature and the real-time humidity and the target pre-drying temperature and the target pre-drying humidity. Based on the pre-drying temperature deviation and the pre-drying humidity deviation, the pre-drying temperature and the pre-drying humidity are adjusted by a PID controller to generate the moisture content after pre-drying;

[0089] In this embodiment, the formula for adjusting the pre-drying temperature and pre-drying humidity by the PID controller is:

[0090]

[0091]

[0092] in, represents the pre-drying temperature deviation, t1 represents the pre-drying time variable, T a represents the target pre-drying temperature, T1(t1) represents the real-time temperature during the pre-drying stage, Indicates the pre-drying humidity deviation, H a represents the target pre-drying humidity, H1(t1) represents the real-time humidity during the pre-drying stage, Indicates the pre-drying temperature control output, represents the pre-drying ratio coefficient, represents the pre-drying integral coefficient, represents the pre-drying differential coefficient, Indicates the pre-drying humidity control output;

[0093] The PID controller consists of three parts: proportional control, integral control and differential control, which process the current value, cumulative value and change rate of the error respectively, and make control adjustments based on this information. Proportional control is used to generate a control signal based on the current error size; integral control is used to generate a control signal based on the cumulative value of the error to eliminate long-term steady-state errors; differential control is used to generate a control signal based on the rate of change of the error, suppress rapid changes in the error, and improve the response speed and stability of the system.

[0094] The proportional coefficient, integral coefficient and differential coefficient of the PID controller can be adjusted through the empirical adjustment method. Turn off the integral control and differential control, start from a smaller set value, gradually increase the proportional coefficient, and observe the system response until the system reaches a stable but not excessively oscillating state, that is, the system has neither continuous large-scale oscillations nor excessive steady-state errors during the response process. On the basis of determining the proportional coefficient, gradually increase the integral coefficient to avoid excessive oscillation caused by integral saturation. When the system responds too slowly or the integral is saturated, appropriately reduce the integral coefficient until the slow response and integral saturation disappear, and record the integral coefficient at this time; on the basis of the adjusted proportional coefficient and integral coefficient, gradually increase the differential coefficient until the high-frequency noise is not significantly amplified.

[0095] The formula for generating the moisture content after pre-drying is:

[0096] W Y =W0-△W Y

[0097] Among them, W Y represents the moisture content after pre-drying, W0 represents the initial moisture content, △W Y Indicates the moisture content reduced during the pre-drying stage.

[0098] The moisture content after pre-drying reflects the changes in moisture inside the cassava starch balls after the pre-drying stage. The moisture sensor is used to monitor the changes in the humidity of the cassava starch balls during the pre-drying stage, thereby obtaining the reduced moisture content during the pre-drying stage. If the moisture content after pre-drying is still high, it may be necessary to delay the drying time or adjust the pre-drying temperature and humidity, otherwise it will affect the subsequent main drying stage and post-drying stage. The moisture after pre-drying is proportional to the initial moisture content and inversely proportional to the moisture content reduced during the pre-drying stage.

[0099] Step 4: In the main drying stage, a high-temperature hot air circulation dryer is used, a target main drying temperature, a target main drying humidity and a main drying time are set, and the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage are monitored in real time, and a main drying temperature deviation and a main drying humidity deviation are generated according to the deviation between the real-time temperature and the real-time humidity and the target main drying temperature and the target main drying humidity. Based on the main drying temperature deviation and the main drying humidity deviation, the main drying temperature and the main drying humidity are adjusted by a PID controller to generate the moisture content after the main drying;

[0100] In this embodiment, the formula used by the PID controller to adjust the main drying temperature and the main drying humidity is:

[0101]

[0102]

[0103] in, represents the main drying temperature deviation, t2 represents the main drying time variable, T b represents the target main drying temperature, T2(t2) represents the real-time temperature during the main drying stage, Indicates the main drying humidity deviation, H b represents the target main drying humidity, H2(t2) represents the real-time humidity in the main drying stage, Indicates the main drying temperature control output, represents the main drying ratio coefficient, represents the main drying integral coefficient, represents the post-drying differential coefficient, Indicates post-drying humidity control output;

[0104] According to the method of adjusting the proportional coefficient, integral coefficient and differential coefficient in the PID controller in step 3, the PID parameters in the main drying stage are adjusted, and the output temperature control and humidity control are used to adjust the main drying temperature and the main drying humidity;

[0105] The formula used to generate the moisture content after main drying is:

[0106] W Z =W Y -△W Z

[0107] Among them, W Z Indicates the moisture content after main drying, W Y Indicates the moisture content after pre-drying, △W Z Indicates the moisture content reduced during the main drying phase.

[0108] The moisture content after main drying reflects the change of moisture inside the cassava starch balls after the main drying stage. The goal is to significantly reduce the moisture content. By evaluating W Z To judge the effect of the main drying stage, if the moisture removal is insufficient, it is necessary to increase the drying time or increase the temperature, otherwise it will affect the drying effect of the post-drying stage. The moisture content after the main drying is proportional to the moisture content after the pre-drying, and inversely proportional to the moisture content reduced in the main drying stage.

[0109] Step 5: In the post-drying stage, a microwave dryer is used to set a target post-drying temperature, a target post-drying humidity and a post-drying time, and the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage are monitored in real time, and a post-drying temperature deviation and a post-drying humidity deviation are generated according to the deviation between the real-time humidity and the real-time humidity and the target post-drying temperature and the target post-drying humidity. Based on the post-drying temperature deviation and the post-drying humidity deviation, the post-drying temperature and the post-drying humidity are adjusted by a PID controller to generate the moisture content after post-drying;

[0110] In this embodiment, the formula used by the PID controller to adjust the post-drying temperature and post-drying humidity is:

[0111]

[0112]

[0113] in, represents the post-drying temperature deviation, t3 represents the post-drying time variable, T c represents the target post-drying temperature, T3(t3) represents the real-time temperature in the post-drying stage, Indicates the post-drying humidity deviation, H c represents the target post-drying humidity, H3(t3) represents the real-time humidity in the post-drying stage, Indicates the post-drying temperature control output, represents the post-drying ratio coefficient, represents the post-drying integral coefficient, represents the post-drying differential coefficient, Indicates post-drying humidity control output;

[0114] According to the method of adjusting the proportional coefficient, integral coefficient and differential coefficient in the PID controller in step 3, the PID parameters in the main drying stage are adjusted, and the output temperature control and humidity control adjust the post-drying temperature and post-drying humidity;

[0115] The moisture content after drying after generation is based on the formula:

[0116] W B =W Z -△W B

[0117] Among them, W B Indicates the moisture content after post-drying, W z Indicates the moisture content after main drying, △W B Indicates the reduced moisture content during the post-drying stage.

[0118] The moisture content after post-drying reflects the final moisture content after the entire drying process. The goal is to fine-tune the moisture content until the final standard. The moisture content after post-drying is proportional to the moisture content after main drying and inversely proportional to the moisture content reduced in the post-drying stage.

[0119] Step 6: After the multi-stage drying is completed, a certain number of samples are randomly selected from the dried cassava starch balls, the moisture content of the selected cassava starch ball samples is detected, the number of cassava starch ball samples within the target moisture content range is calculated, and the qualified rate is generated;

[0120] In this embodiment, the formula for generating the qualified rate is:

[0121]

[0122] Among them, R represents the qualified rate, N represents the number of cassava starch ball samples taken, and n represents the number of samples among the cassava starch ball samples taken whose moisture content is within the target moisture content range.

[0123] Step 7: Preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, reduce the proportional coefficient; when the pass rate is less than the pass rate threshold, increase the proportional coefficient.

[0124] In this embodiment, the formula for adjusting the proportional coefficient of the PID controller in each drying stage is:

[0125] The adjustment formula for the pre-drying stage is:

[0126]

[0127] in, Indicates the pre-drying ratio coefficient after adjustment, represents the pre-drying ratio coefficient, R represents the qualified rate, R0 represents the qualified rate threshold, δ1 represents the pre-drying adjustment index, -1≤δ1≤1, and when R>R0, δ1<0, when R<R0, δ1>0;

[0128] The adjustment formula for the main drying stage is:

[0129]

[0130] in, Indicates the main drying ratio coefficient after adjustment, represents the main drying ratio coefficient, δ2 represents the main drying adjustment index, -1≤δ2≤1, and when R>R0, δ2<0, when R<R0, δ2>0;

[0131] The adjustment formula for the post-drying stage is:

[0132]

[0133] in, Represents the post-drying ratio coefficient after adjustment, represents the post-drying proportional coefficient, δ3 represents the post-drying adjustment index, -1≤δ3≤1, and when R>R0, δ3<0, when R<R0, δ3>0.

[0134] The proportional coefficient adjusts the control output according to the current deviation value, reflecting the system's sensitivity to the current deviation. The larger the proportional coefficient, the faster the system responds to the error. A higher proportional coefficient can reduce the steady-state error, but may cause the system to oscillate around the set value. Therefore, the system's sensitivity to the deviation is adjusted according to the pass rate.

[0135] When the qualified rate is higher than the qualified rate threshold, it means that the drying process is relatively stable, and the proportional coefficient can be appropriately reduced to avoid overreaction. At this time, the corresponding adjustment index is a negative number, indicating that the proportional coefficient of the drying process is reduced; when the qualified rate is lower than the qualified rate threshold, it means that the drying effect is not ideal, and the proportional coefficient needs to be increased to enhance the response sensitivity of the temperature deviation and humidity deviation. At this time, the corresponding adjustment index is a positive number, indicating that the proportional coefficient of the drying process is increased;

[0136] When determining the initial value of the adjustment index, select a number close to 0 from -1 to 1 as the initial test value and start trying. Record the impact of different adjustment indexes on the pass rate and use a step-by-step test method to determine the optimal value.

[0137] See also Figure 2 The present invention also provides a moisture control system for the production process of cassava starch dumplings, and the system is used to implement the moisture control method for the production process of cassava starch dumplings, which specifically includes:

[0138] The moisture detection module is used to select a certain mass of cassava starch ball samples and put them into the oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content;

[0139] The drying classification module is used to divide the drying stages of cassava starch balls into pre-drying, main drying and post-drying based on multi-stage drying, and set different target drying temperatures and target drying humidity in each stage;

[0140] A pre-drying module is used to use a low-temperature hot air circulation dryer in the pre-drying stage, set a target pre-drying temperature, a target pre-drying humidity and a pre-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage in real time, generate a pre-drying temperature deviation according to the deviation between the real-time temperature and the target pre-drying temperature, generate a pre-drying humidity deviation according to the deviation between the real-time humidity and the target pre-drying humidity, and adjust the pre-drying temperature and pre-drying humidity through a PID controller based on the pre-drying temperature deviation and the pre-drying humidity deviation to generate the moisture content after pre-drying;

[0141] A main drying module is used to use a high-temperature hot air circulation dryer in the main drying stage, set a target main drying temperature, a target main drying humidity and a main drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage in real time, generate a main drying temperature deviation according to the deviation between the real-time temperature and the target main drying temperature, generate a main drying humidity deviation according to the deviation between the real-time humidity and the target main drying humidity, and adjust the main drying temperature and the main drying humidity through a PID controller based on the main drying temperature deviation and the main drying humidity deviation to generate the moisture content after the main drying;

[0142] A post-drying module is used to use a microwave dryer in the post-drying stage to set a target post-drying temperature, a target post-drying humidity and a post-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage in real time, generate a post-drying temperature deviation according to the deviation between the real-time temperature and the target post-drying temperature, generate a post-drying humidity deviation according to the deviation between the real-time humidity and the target post-drying humidity, and adjust the post-drying temperature and the post-drying humidity through a PID controller based on the post-drying temperature deviation and the post-drying humidity deviation to generate the moisture content after post-drying;

[0143] The effect evaluation module is used to randomly extract a certain number of samples from the dried cassava starch balls after the multi-stage drying is completed, detect the moisture content of the extracted cassava starch ball samples, calculate the number of cassava starch ball samples within the target moisture content range, and generate a qualified rate;

[0144] The feedback adjustment module is used to preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the size relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, the proportional coefficient is reduced, and when the pass rate is less than the pass rate threshold, the proportional coefficient is increased. The above formulas are all dimensionless and numerical calculations. The formula is a formula obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0145] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0146] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0147] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A moisture control method for the production process of cassava starch dumplings, characterized in that: The specific steps include: Step 1: Select a certain mass of cassava starch ball samples and put them into an oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content; Step 2: Based on multi-stage drying, the drying stages of cassava starch balls are divided into pre-drying, main drying and post-drying, and different target drying temperatures and target drying humidity are set in each stage; Step 3: In the pre-drying stage, a low-temperature hot air circulation dryer is used, a target pre-drying temperature, a target pre-drying humidity and a pre-drying time are set, and the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage are monitored in real time, and a pre-drying temperature deviation is generated according to the deviation between the real-time temperature and the target pre-drying temperature, and a pre-drying humidity deviation is generated according to the deviation between the real-time humidity and the target pre-drying humidity, and based on the pre-drying temperature deviation and the pre-drying humidity deviation, the pre-drying temperature and the pre-drying humidity are adjusted by a PID controller to generate the moisture content after pre-drying; Step 4: In the main drying stage, a high-temperature hot air circulation dryer is used, a target main drying temperature, a target main drying humidity and a main drying time are set, and the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage are monitored in real time. A main drying temperature deviation is generated according to the deviation between the real-time temperature and the target main drying temperature, and a main drying humidity deviation is generated according to the deviation between the real-time humidity and the target main drying humidity. Based on the main drying temperature deviation and the main drying humidity deviation, the main drying temperature and the main drying humidity are adjusted by a PID controller to generate the moisture content after the main drying; Step 5: In the post-drying stage, a microwave dryer is used to set a target post-drying temperature, a target post-drying humidity and a post-drying time, and the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage are monitored in real time, and a post-drying temperature deviation is generated according to a deviation between the real-time temperature and the target post-drying temperature, and a post-drying humidity deviation is generated according to a deviation between the real-time humidity and the target post-drying humidity, and based on the post-drying temperature deviation and the post-drying humidity deviation, the post-drying temperature and the post-drying humidity are adjusted by a PID controller to generate the moisture content after post-drying; Step 6: After the multi-stage drying is completed, a certain number of samples are randomly selected from the dried cassava starch balls, the moisture content of the selected cassava starch ball samples is detected, the number of cassava starch ball samples within the target moisture content range is calculated, and the qualified rate is generated; Step 7: Preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, reduce the proportional coefficient; when the pass rate is less than the pass rate threshold, increase the proportional coefficient.

2. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula for generating the initial moisture content in step 1 is: Where W0 represents the initial moisture content, M0 represents the mass of the cassava sample before drying, and M g Indicates the mass of cassava samples after drying.

3. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The target drying temperature in each drying stage is as follows: T b >T c >T a Among them, T b represents the target main drying temperature, T c represents the target post-drying temperature, T a Indicates the target pre-drying temperature; The target drying humidity in each drying stage is as follows: H a >H b >H c Among them, H a Indicates the target pre-drying humidity, H b Indicates the target main drying humidity, H c Indicates the target post-drying humidity.

4. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula used by the PID controller to adjust the pre-drying temperature and pre-drying humidity in step 3 is: in, represents the pre-drying temperature deviation, t1 represents the pre-drying time variable, T a represents the target pre-drying temperature, T1(t1) represents the real-time temperature during the pre-drying stage, Indicates the pre-drying humidity deviation, H a represents the target pre-drying humidity, H1(t1) represents the real-time humidity during the pre-drying stage, Indicates the pre-drying temperature control output, represents the pre-drying ratio coefficient, represents the pre-drying integral coefficient, represents the pre-drying differential coefficient, Indicates the pre-drying humidity control output; The formula for generating the moisture content after pre-drying is: IN Y =W0-△W Y Among them, W Y represents the moisture content after pre-drying, W0 represents the initial moisture content, △W Y Indicates the moisture content reduced during the pre-drying stage.

5. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula used by the PID controller to adjust the main drying temperature and the main drying humidity in step 4 is: in, represents the main drying temperature deviation, t2 represents the main drying time variable, T b represents the target main drying temperature, T2(t2) represents the real-time temperature during the main drying stage, Indicates the main drying humidity deviation, H b represents the target main drying humidity, H2(t2) represents the real-time humidity in the main drying stage, Indicates the main drying temperature control output, represents the main drying ratio coefficient, represents the main drying integral coefficient, represents the main drying differential coefficient, Indicates the main drying humidity control output; The formula used to generate the moisture content after main drying is: IN Z =In Y -△W Z Among them, W Z Indicates the moisture content after main drying, W Y Indicates the moisture content after pre-drying, △W Z Indicates the moisture content reduced during the main drying phase.

6. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula used by the PID controller to adjust the post-drying temperature and post-drying humidity in step 5 is: in, represents the post-drying temperature deviation, t3 represents the post-drying time variable, T c represents the target post-drying temperature, T3(t3) represents the real-time temperature in the post-drying stage, Indicates the post-drying humidity deviation, H c represents the target post-drying humidity, H3(t3) represents the real-time humidity in the post-drying stage, Indicates the post-drying temperature control output, represents the post-drying ratio coefficient, represents the post-drying integral coefficient, represents the post-drying differential coefficient, Indicates post-drying humidity control output; The moisture content after drying after generation is based on the formula: IN B =In Z -△W B Among them, W B Indicates the moisture content after post-drying, W Z Indicates the moisture content after main drying, △W B Indicates the reduced moisture content during the post-drying stage.

7. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula for generating the pass rate in step 6 is: Among them, R represents the qualified rate, N represents the number of cassava starch ball samples taken, and n represents the number of samples among the cassava starch ball samples taken whose moisture content is within the target moisture content range.

8. A method for controlling moisture in a tapioca starch dumpling production process according to claim 1, characterized in that: The formula for adjusting the proportional coefficient of the PID controller in each drying stage in step 7 is: The adjustment formula for the pre-drying stage is: in, Indicates the pre-drying ratio coefficient after adjustment, represents the pre-drying ratio coefficient, R represents the qualified rate, R0 represents the qualified rate threshold, δ1 represents the pre-drying adjustment index, -1≤δ1≤1, and when R>R0, δ1<0, when R<R0, δ1>0; The adjustment formula for the main drying stage is: in, Indicates the main drying ratio coefficient after adjustment, represents the main drying ratio coefficient, δ2 represents the main drying adjustment index, -1≤δ2≤1, and when R>R0, δ2<0, when R<R0, δ2>0; The adjustment formula for the post-drying stage is: in, Represents the post-drying ratio coefficient after adjustment, represents the post-drying proportional coefficient, δ3 represents the post-drying adjustment index, -1≤δ3≤1, and when R>R0, δ3<0, when R<R0, δ3>0.

9. A moisture control system for the production process of cassava starch dumplings, characterized in that: The system is used to implement the moisture control method for the cassava starch dumpling production process according to any one of claims 1 to 8, specifically comprising: The moisture detection module is used to select a certain mass of cassava starch ball samples and put them into the oven, dry them at 105°C to constant weight, record the mass before and after drying, and generate the initial moisture content; The drying classification module is used to divide the drying stages of cassava starch balls into pre-drying, main drying and post-drying based on multi-stage drying, and set different target drying temperatures and target drying humidity in each stage; A pre-drying module is used to use a low-temperature hot air circulation dryer in the pre-drying stage, set a target pre-drying temperature, a target pre-drying humidity and a pre-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the pre-drying stage in real time, generate a pre-drying temperature deviation according to the deviation between the real-time temperature and the target pre-drying temperature, generate a pre-drying humidity deviation according to the deviation between the real-time humidity and the target pre-drying humidity, and adjust the pre-drying temperature and pre-drying humidity through a PID controller based on the pre-drying temperature deviation and the pre-drying humidity deviation to generate the moisture content after pre-drying; A main drying module is used to use a high-temperature hot air circulation dryer in the main drying stage, set a target main drying temperature, a target main drying humidity and a main drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the main drying stage in real time, generate a main drying temperature deviation according to the deviation between the real-time temperature and the target main drying temperature, generate a main drying humidity deviation according to the deviation between the real-time humidity and the target main drying humidity, and adjust the main drying temperature and the main drying humidity through a PID controller based on the main drying temperature deviation and the main drying humidity deviation to generate the moisture content after the main drying; A post-drying module is used to use a microwave dryer in the post-drying stage to set a target post-drying temperature, a target post-drying humidity and a post-drying time, monitor the real-time temperature and real-time humidity of the cassava starch ball sample in the post-drying stage in real time, generate a post-drying temperature deviation according to the deviation between the real-time temperature and the target post-drying temperature, generate a post-drying humidity deviation according to the deviation between the real-time humidity and the target post-drying humidity, and adjust the post-drying temperature and the post-drying humidity through a PID controller based on the post-drying temperature deviation and the post-drying humidity deviation to generate the moisture content after post-drying; The effect evaluation module is used to randomly extract a certain number of samples from the dried cassava starch balls after the multi-stage drying is completed, detect the moisture content of the extracted cassava starch ball samples, calculate the number of cassava starch ball samples within the target moisture content range, and generate a qualified rate; The adjustment feedback module is used to preset the pass rate threshold, and adjust the proportional coefficient of the PID controller in each drying stage according to the size relationship between the pass rate and the pass rate threshold. When the pass rate is greater than the pass rate threshold, the proportional coefficient is reduced, and when the pass rate is less than the pass rate threshold, the proportional coefficient is increased.

Images