A method for stabilizing and regulating the moisture content of the outlet of a tobacco primary feeder

Abstract

The application discloses a tobacco primary processing machine material head stage outlet moisture stable control method, comprising constructing a sigmoid water adding flow characteristic curve model, which is used for describing the water adding flow characteristics of the material head stage and has a duration T1 and a holding time T2; the duration T1 is adjusted according to the operation law of the material adding machine, the water adding flow is matched with the tobacco flow, the outlet moisture content is ensured to be stable, and the optimal T1 value is determined by observing the outlet moisture content change; the water adding flow is controlled through the sigmoid water adding flow characteristic curve model with the optimal T1 value; after the water adding flow reaches a set m value and keeps the flow value for T2 time, the water adding flow is dynamically adjusted by switching to an automatic control mode, so that the outlet moisture of the tobacco is stably controlled; the application can realize the stable control of the outlet moisture of the material head stage of the material adding machine, so that the outlet moisture of the material head stage of the material adding machine can be quickly and stably kept near the outlet moisture target value.

Description

Technical Field

[0001] This invention relates to a method for stabilizing and controlling the outlet moisture content of a tobacco processing feeder at the feed head stage, belonging to the field of cigarette processing technology. Background Technology

[0002] In addition to applying the slurry, the tobacco processing feeder also needs to heat and humidify the tobacco leaves during operation. Based on feedback from the moisture content of the tobacco leaves at the feeder inlet and inside the feed cylinder, the control system injects humidifying water and compensating steam into the feed cylinder to rapidly heat and humidify the leaves, thereby ensuring that the moisture content of the tobacco leaves at the outlet meets the process requirements. At the beginning of production, due to the small amount of tobacco leaves fed and the time lag in the moisture content at the feeder outlet, feedback control methods such as PID cannot intervene and cannot perform real-time feedback water addition control. This situation leads to uneven or large fluctuations in the moisture content at the feeder outlet, making it difficult to achieve the target moisture content. This not only affects the subsequent drying process but also increases the consumption of tobacco materials.

[0003] Current research on moisture control in cigarette manufacturing processes mostly focuses on the drying process, with less research on the stability of moisture content at the feed head stage. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for stable control of the outlet moisture of a tobacco processing feeder at the feed head stage. This method proposes to use a smooth trend function to control the water flow rate at the feed head stage of the feeder, and to analyze and summarize the general control rules of the production law at the feed head stage of the feeder. By using this model and control method to add water to the tobacco leaves at the feed head stage of the feeder, the outlet moisture of the feeder at the feed head stage can be stably controlled, thereby ensuring that the outlet moisture of the feeder at the feed head stage can be stabilized near the target outlet moisture value as soon as possible.

[0005] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0006] In a first aspect, the present invention provides a method for stabilizing and controlling the outlet moisture content of a tobacco processing feeder at the feed head stage, comprising:

[0007] A sigmoid water flow rate characteristic curve model is constructed to describe the water flow rate characteristics in the feed head stage. The sigmoid water flow rate characteristic curve model is based on the sigmoid function and includes the correspondence between water flow rate and time, with duration T1 and holding time T2.

[0008] The duration T1 is adjusted according to the operating pattern of the feeder to match the water flow rate with the tobacco flow rate, ensuring stable outlet moisture content. The optimal T1 value is determined by observing the change in outlet moisture content.

[0009] The water flow rate is controlled by setting the optimal T1 value using a sigmoid water flow rate characteristic curve model.

[0010] After the water flow rate reaches the set value m and is maintained at that value for a time T2, the system switches to automatic control mode. The automatic control mode provides feedback based on real-time tobacco leaf outlet moisture data and dynamically adjusts the water flow rate to achieve stable control of tobacco leaf outlet moisture.

[0011] Furthermore, T1 represents the time it takes for the water flow rate to increase from an approximate minimum to an approximate maximum, and T2 represents the time it takes to maintain the target water flow rate after reaching it.

[0012] Furthermore, determining the optimal T1 value by observing changes in outlet moisture content includes:

[0013] When the T1 value is reduced until the "initial peak overshoot trend" disappears or decreases significantly, the T1 value at this time is determined as the optimal duration of the sigmoid water addition flow characteristic curve model. The "initial peak overshoot trend" indicates that the water addition rate of the sigmoid water addition flow characteristic curve model enters the terminal plateau stage and the outlet moisture content shows a downward trend.

[0014] Furthermore, the construction of the sigmoid water flow characteristic curve model includes using the domain of the sigmoid function as a time variable and mapping its vertical axis range to the target value of the water flow, while ensuring that when the water flow in the range is close to 0, the corresponding domain time is 0.

[0015] Furthermore, the calculation formula for the sigmoid water flow characteristic curve model is as follows:

[0016]

[0017] Where t is the system running time; f is the water flow rate; and e is a natural constant in mathematics.

[0018] Furthermore, the optimal setting for T1 is 60s.

[0019] Furthermore, the adjustment process of the T1 value is divided into three cases: overshoot and long oscillation time, no overshoot and no oscillation, and undershoot and overshoot.

[0020] Furthermore, the adjustment process of the T1 value includes: analyzing historical data adjustment trends; if an "initial peak overshoot trend" occurs, T1 is increased; if there is no overshoot and no oscillation, the current T1 is kept as the optimal value; if an "initial peak undershoot trend" occurs, T1 is decreased. The "initial peak undershoot trend" indicates that the sigmoid water flow characteristic curve model has entered a rapid growth stage, and the outlet moisture content has returned to an increasing trend.

[0021] Secondly, the present invention provides a system for stabilizing and controlling the moisture content at the outlet of a tobacco processing feeder during the feed head stage. When the system is run by a computer, it executes the method for stabilizing and controlling the moisture content at the outlet of the tobacco processing feeder during the feed head stage as described in any of the preceding claims.

[0022] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0023] 1. This invention analyzes and summarizes the general control rules of the production law in the material head stage of the feeding machine, and transforms the basic Sigmod function through mathematical methods to obtain the water flow characteristic curve model of the material head stage of the feeding machine.

[0024] 2. In this invention, when T1 is 60s, the water flow rate at the feed head stage is modeled. Using this model, the water supply to the tobacco leaves at the feed head stage of the feeder is regulated, and the resulting outlet tobacco leaf moisture content is optimal.

[0025] 3. This model and control method are used to add water to the tobacco leaves at the feed head stage of the feeder, so as to achieve stable control of the outlet moisture of the feed head stage and ensure that the outlet moisture of the feeder stabilizes at near the target value as soon as possible. Attached Figure Description

[0026] Figure 1 This is a flowchart of a method for stabilizing the outlet moisture content of a tobacco processing feeder at the feed head stage, provided by an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of the sigmoid basic function curve provided in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram of the characteristic curve function of water flow rate at the feed head stage of the feeder provided in an embodiment of the present invention.

[0029] Figure 4 This is a schematic diagram of the characteristic curve function for water flow regulation in the feed head stage of the feeder provided in an embodiment of the present invention.

[0030] Figures 5 to 11 This is a graph showing the actual moisture content at the feeder outlet under different model durations provided in this embodiment of the invention.

[0031] Figures 12 to 14 This is an analysis diagram of the moisture adjustment process at the outlet of the feeder provided in an embodiment of the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment introduces a method for stabilizing and controlling the outlet moisture content of a tobacco processing feeder at the feed head stage, including:

[0035] A sigmoid water flow rate characteristic curve model is constructed to describe the water flow rate characteristics in the feed head stage. The sigmoid water flow rate characteristic curve model is based on the sigmoid function and includes the correspondence between water flow rate and time, with duration T1 and holding time T2.

[0036] The duration T1 is adjusted according to the operating pattern of the feeder to match the water flow rate with the tobacco flow rate, ensuring stable outlet moisture content. The optimal T1 value is determined by observing the change in outlet moisture content.

[0037] The water flow rate is controlled by setting the optimal T1 value using a sigmoid water flow rate characteristic curve model.

[0038] After the water flow rate reaches the set value m and is maintained at that value for a time T2, the system switches to automatic control mode. The automatic control mode provides feedback based on real-time tobacco leaf outlet moisture data and dynamically adjusts the water flow rate to achieve stable control of tobacco leaf outlet moisture.

[0039] The method for stabilizing and controlling the outlet moisture content of a tobacco shredding feeder at the feed head stage provided in this embodiment involves the following steps in its application:

[0040] The flowchart of the present invention is as follows Figure 1 As shown.

[0041] Step 1: Construct a sigmoid flow rate characteristic curve model for the feed head stage. Equation (1) is the basic sigmoid function expression. Figure 2 This is a graph of the sigmoid function.

[0042]

[0043] Depend on Figure 2 It can be observed that: the function initially grows slowly with a small slope, followed by an exponential growth range; near x=0, the function exhibits quasi-linear growth with a large slope; thereafter, the growth rate gradually slows down until a stable value is reached.

[0044] Because the Sigmoid function exhibits smooth start and end phases within its specified domain, it can further mitigate overshoot. The function's domain is used as the time variable, and the vertical axis range is used as the target water flow rate. Since the basic Sigmoid function is symmetric to 0, the domain time is negative when the water flow rate is close to 0. Therefore, the function needs to be transformed so that its domain time is 0 when the water flow rate is close to 0.

[0045] Furthermore, to facilitate the adjustment of the function's growth trend, a duration variable T1 and a hold-up time variable T2 are proposed for the Sigmoid function. The duration variable T1 represents the time taken for the water flow rate to increase from its approximate minimum to its approximate maximum value within the Sigmoid function's range. The hold-up time variable T2 represents the time it takes for the Sigmoid function to maintain the target water flow rate value after reaching it as time T1 increases.

[0046] This invention patent uses the Sigmod function to describe this law and defines a characteristic function model of water flow rate in the feeder head stage to describe the characteristic function of water flow rate in the feeder head stage. Now, the Sigmod curve function is parametrically transformed into a model starting from 0, resulting in the following expression (2) and characteristic curve function. Figure 3 :

[0047]

[0048] like Figure 4 The figure shows the characteristic curve function of water flow rate regulation in the feed head stage of the feeder. As the duration T1 of the Sigmod function increases, the growth trend of water flow rate gradually slows down. By observing the effect of this variable on water flow rate, the final process indicator, the moisture content at the feeder outlet, can be regulated.

[0049] Step 2: Given a water flow rate of m. The actual control model for the water flow rate using Sigmod is shown in equation (3).

[0050]

[0051] Where t is the system running time; f is the water flow rate; and e is a natural constant in mathematics, an infinite non-repeating decimal and a transcendental number, with a value of approximately 2.718281828459045.

[0052] Step 3: Exploring the operating rules of the feeding machine.

[0053] Figures 5-11The graph shows the actual moisture content at the feeder outlet under different model durations. The shorter the Sigmod model duration, the faster the water flow rate increases in the initial startup phase. Near the startup phase, the water flow rate exceeds the tobacco leaf growth rate, resulting in an imbalance between water and tobacco flow rates and a higher outlet moisture content. Subsequently, the water flow rate of the Sigmod model enters a plateau phase, and the outlet moisture content shows a downward trend, ultimately exhibiting an "initial peak overshoot trend" in the graph. Conversely, the longer the Sigmod model duration, the smaller the water flow rate increases in the initial startup phase. Near the startup phase, the water flow rate is less than the tobacco leaf growth rate, resulting in an imbalance between water and tobacco flow rates and a downward trend in outlet moisture content. Subsequently, the water flow rate of the Sigmod model enters a rapid growth phase, and the outlet moisture content returns to an upward trend, ultimately exhibiting an "initial peak undershoot trend" in the graph.

[0054] By gradually changing the duration of the Sigmod function model from large to small, and observing the change of the "initial peak overshoot trend" through the image, it is found that the "initial peak overshoot trend" disappears or becomes smaller as the duration decreases, indicating that the growth rate of tobacco leaf flow rate and the growth rate of water flow rate are well matched. The duration of the Sigmod function at this moment is taken as the optimal duration of the model.

[0055] Based on the summary of the adjustment trends of the historical data mentioned above, the adjustment process can be divided into the following categories: Figures 12-14 There are three scenarios: overshoot and long oscillation time; no overshoot and no oscillation; and undershoot and overshoot. Analysis shows that if, given a T1 value, the actual moisture content at the feeder outlet shows overshoot, then T1 needs to be increased. If the moisture content at the feeder outlet shows no overshoot, then T1 is the optimal value. In this invention, when T1 is 60s, water is added to the tobacco leaves at the feed head stage, resulting in the optimal moisture content at the feeder outlet. If the moisture content at the feeder outlet shows undershoot, then T1 needs to be decreased.

[0056] Step 4: After maintaining the water flow rate m for time T2, switch to automatic control mode to regulate the moisture content of the tobacco leaves at the outlet during the stable phase.

[0057] Example 2

[0058] This embodiment provides a system for stabilizing and controlling the outlet moisture of a tobacco processing feeder at the feed head stage. When the system is run by a computer, it executes the method for stabilizing and controlling the outlet moisture of the tobacco processing feeder at the feed head stage as described in any of the preceding embodiments.

[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for regulating moisture stability at the exit of the tobacco primary conditioning section of a tobacco primary conditioning machine, characterized in that, include: A sigmoid water flow rate characteristic curve model is constructed to describe the water flow rate characteristics in the feed head stage. The sigmoid water flow rate characteristic curve model is based on the sigmoid function and includes the correspondence between water flow rate and time, with a duration T1 and a holding time T2. T1 represents the time it takes for the water flow rate to increase from an approximate minimum value to an approximate maximum value, and T2 represents the time it takes to maintain the water flow rate after reaching the target value. The duration T1 is adjusted according to the operating pattern of the feeder to match the water flow rate with the tobacco flow rate, ensuring stable outlet moisture content. The optimal T1 value is determined by observing the change in outlet moisture content. include: When the T1 value is reduced until the initial peak overshoot trend disappears or decreases significantly, the T1 value at this time is determined as the optimal setting duration of the sigmoid water addition flow characteristic curve model. The initial peak overshoot trend indicates that the water addition rate of the sigmoid water addition flow characteristic curve model enters the terminal flat stage and the outlet moisture content shows a downward trend. The water flow rate is controlled by setting the optimal T1 value using a sigmoid water flow rate characteristic curve model. After the water flow rate reaches the set value m and is maintained at that value for a time T2, the system switches to automatic control mode. The automatic control mode provides feedback based on real-time tobacco leaf outlet moisture data and dynamically adjusts the water flow rate to achieve stable control of tobacco leaf outlet moisture. The calculation formula for the sigmoid water flow characteristic curve model is as follows: Where t is the system running time; f is the water flow rate; e is a natural constant in mathematics; and m is the set water flow rate. The adjustment process of the T1 value includes: analyzing the adjustment trend of historical data; if an initial peak overshoot trend appears, increase T1; if there is no overshoot and no oscillation, keep the current T1 as the optimal value; if an initial peak undershoot trend appears, decrease T1. The initial peak undershoot trend indicates that the sigmoid water addition flow characteristic curve model has entered a rapid growth stage and the outlet moisture content has returned to an increasing trend.

2. The tobacco primary processing head-end moisture stabilization control method of claim 1, wherein, The construction of the sigmoid water flow characteristic curve model involves taking the domain of the sigmoid function as a time variable and mapping its vertical axis range to the target value of the water flow.

3. The tobacco primary processing head-end moisture stabilization control method of claim 1, wherein, The optimal setting for T1 is 60s.

4. The tobacco primary processing head-end moisture stabilization control method of claim 1, wherein, The adjustment process of the T1 value is divided into three cases: overshoot and long oscillation time, no overshoot and no oscillation, and undershoot and overshoot.

5. A system for stabilizing and controlling the outlet moisture content of a tobacco processing feeder at the feed head stage, characterized in that, include: When the system is run by a computer, it executes the method for stabilizing and controlling the outlet moisture of the tobacco processing feeder at the feed head stage as described in any one of claims 1-4.

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