A method for experimentally obtaining a material temperature control model of a silk reeling and leaf conditioning machine

Abstract

The present invention discloses a method for experimentally obtaining a material temperature control model of a leaf conditioning machine in cigarette cut tobacco production, belonging to the technical field of cigarette cut tobacco production. The method includes entering the production stage when the leaf conditioning machine meets the production conditions; performing temperature control on the leaf conditioning machine during the production stage, and defining the stable stage of the temperature control of the leaf conditioning machine in a formulaic form; when the temperature control of the leaf conditioning machine enters the stable stage, approximating the non-linear time-varying system as a linearized constant system, and obtaining the material temperature control model of the leaf conditioning machine in cigarette cut tobacco production. The present invention solves the problems in the prior art that the temperature control during the leaf conditioning process is relatively complex, and the control strategy adopted for the purpose of improving the control model lacks an accurate mathematical model. This method has good feasibility and high accuracy. At the same time, since the model is simple and has fewer parameters, it is easy to modify the parameters later to correct the model again, effectively improving the stability, accuracy and rapidity of the material temperature control under specific production conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of cigarette leaf processing, and particularly to a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette leaf processing. Background Art

[0002] Due to the strong non-linearity, uncertainty, and large time lag in the leaf conditioning and humidifying process, combined with the special properties of the tobacco leaves themselves, the temperature control in the leaf conditioning process becomes very complex. Essentially, the material temperature control of a leaf conditioning machine for cigarette leaf processing belongs to a non-linear time-varying system, and can be approximately regarded as a linear time-invariant system in some relatively stable production stages. However, control strategies such as time-delay Smith control, fuzzy control, neural network, adaptive control, and predictive control, which are aimed at improving the control model, often require an accurate mathematical model. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies in the prior art, and provide a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette leaf processing, to solve the problem that the temperature control in the leaf conditioning process in the prior art is relatively complex, and the control strategies aimed at improving the control model lack an accurate mathematical model, and to approximately obtain the properties and parameters of an accurate mathematical model in relatively stable production stages, thereby obtaining the stability, stability margin, accuracy, and time-domain fast response characteristics of the material temperature control model of the leaf conditioning machine for cigarette leaf processing, so as to further improve and correct the accurate mathematical model.

[0004] To achieve the above purpose, the present invention is implemented by adopting the following technical solutions:

[0005] The present invention provides a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette leaf processing, including:

[0006] Enter the production stage when the leaf conditioning machine meets the production conditions;

[0007] Conduct temperature control on the leaf conditioning machine during the production stage, and define the stable stage of the temperature control of the leaf conditioning machine in a formulaic form;

[0008] When the temperature control of the leaf conditioning machine enters the stable stage, approximate the non-linear time-varying system as a linearized time-invariant system, and obtain the material temperature control model of the leaf conditioning machine for cigarette leaf processing.

[0009] [[ID=3l]]Further, the conducting temperature control on the leaf conditioning machine during the production stage includes:

[0010] Use a PID control module to control the hot air temperature, process direct injection steam, water addition loop, and exhaust negative pressure in the heat source control loop of the leaf conditioning machine;

[0011] The set value SP in the PID control module is defined as a preset set value of the heat source control loop in the production stage, and the preset set value includes equipment parameters and / or recipe parameters.

[0012] Furthermore, the temperature control of the leaf moistening machine during the production stage also includes:

[0013] When the outlet temperature sensor detects the outlet material temperature value, the hot air temperature is used as the main heat source control loop; the hot air temperature is used to control the outlet material temperature;

[0014] Cancel the preset setting value of the hot air control loop, and feed back the outlet material temperature value to the setting value SP of the hot air temperature PID control loop through conversion through a specific formula to perform closed-loop control.

[0015] Furthermore, the definition of the stable phase of the temperature control of the leaf moistening machine includes:

[0016] The hot air temperature in the heat source control circuit of the leaf moistening machine is 1 # PID loop and process direct steam injection 2 # The PID loop enters the temperature control stable state;

[0017] Among them, the hot air temperature 1 during the time period lasting longer than time1 # The absolute value of the difference between the set value SP1 of the PID loop and the actual value PV1 is lower than the threshold TV1;

[0018] Process direct steam injection 2 for a duration exceeding time2 # The absolute value of the difference between the set value SP2 of the PID loop and the actual value PV2 is lower than the threshold TV2; the process direct steam injection 2 lasts for more than time2 # The output value CV2 of the PID loop is lower than the threshold value TV4.

[0019] Furthermore, the definition formula of the stable stage of the temperature control of the leaf moistening machine includes:

[0020] For hot air temperature 1 # PID loop, and the duration exceeds time1:

[0021] |SP1-PV1|<TV1;

[0022] Where PV1 is the actual value of the hot air temperature during the stable temperature control phase of the leaf moistening machine, SP1 is the set value of the hot air temperature during the stable temperature control phase of the leaf moistening machine, and TV1 is the hot air temperature 1 during the stable temperature control phase of the leaf moistening machine. # Threshold value of PID loop;

[0023] For process direct injection steam 2 # PID loop, and the duration exceeds time1:

[0024] |SP2 - PV2| < TV2;

[0025] In the formula, PV2 is the actual value of the process direct injection steam in the stable stage of the leaf moistening machine temperature control, SP2 is the set value of the process direct injection steam in the stable stage of the leaf moistening machine temperature control, and TV2 is the threshold value of the process direct injection steam 2 in the stable stage of the leaf moistening machine temperature control # Threshold of the PID loop.

[0026] Furthermore, the definition of the stable stage of the leaf moistening machine moisture control also includes:

[0027] Keep the opening of the hot air temperature control diaphragm valve and the opening of the direct injection steam control diaphragm valve relatively stable; keep the water addition amount and the exhaust negative pressure relatively stable;

[0028] The relatively stable opening of the hot air temperature control diaphragm valve includes that the output value CV1 of the hot air temperature 1 # PID loop remains lower than the threshold value TV3, and the relatively stable opening of the direct injection steam control diaphragm valve includes that the output value CV2 of the process direct injection steam 2 # PID loop remains lower than the threshold value TV4;

[0029] The relatively stable water addition amount and exhaust negative pressure include the water addition control 3 # PID loop and the exhaust negative pressure 4 # PID loop enters the temperature stable state;

[0030] Among them, within the time when the duration exceeds time3, the absolute value of the difference between the set value SP3 and the actual value PV3 of the water addition control 3 # PID loop remains lower than the threshold value TV5; within the time when the duration exceeds time3, the absolute value of the difference between the set value SP4 and the actual value PV4 of the exhaust negative pressure 4 # PID loop remains lower than the threshold value TV6;

[0031] The relatively stable water addition amount and exhaust negative pressure also include that the water addition control loop controls the pump body speed relatively stable and the exhaust negative pressure valve opening relatively stable;

[0032] Among them, within the time when the duration exceeds time4, the output value CV3 of the water addition control 3 # PID loop remains lower than the threshold value TV7; within the time when the duration exceeds time4, the output value CV4 of the exhaust negative pressure 4 # PID loop remains lower than the threshold value TV8.

[0033] Furthermore, the definition formula for the stable stage of the moisture control of the leaf conditioning machine further includes:

[0034] For the hot air temperature 1 # PID loop, and the duration exceeds time2,

[0035] CV1 < TV3;

[0036] Wherein, CV1 is the output value of the PID loop of the hot air temperature 1# in the stable stage of the temperature control of the leaf conditioning machine, and TV3 is the hot air temperature 1 in the stable stage of the temperature control of the leaf conditioning machine # Threshold of the PID loop;

[0037] For the process direct injection steam 2 # PID loop, and the duration exceeds time2,

[0038] CV2 < TV4;

[0039] Wherein, CV2 is the output value of the PID loop of the process direct injection steam 2# in the stable stage of the temperature control of the leaf conditioning machine, and TV4 is the process direct injection steam 2 in the stable stage of the temperature control of the leaf conditioning machine # Threshold of the PID loop;

[0040] For the water addition control 3 # PID loop, and the duration exceeds time3,

[0041] |SP3 - PV3| < TV5;

[0042] Wherein, SP3 is the set value of the PID loop of the water addition control 3# in the stable stage of the temperature control of the leaf conditioning machine, PV3 is the actual value of the PID loop of the water addition control 3# in the stable stage of the temperature control of the leaf conditioning machine, and TV5 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # Threshold of the PID loop;

[0043] For the exhaust moisture negative pressure 4 # PID loop, and the duration exceeds time3,

[0044] |SP4 - PV4| < TV6;

[0045] Wherein, SP4 is the set value of the PID loop of the exhaust moisture negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # PID loop, PV4 is the actual value of the PID loop of the exhaust moisture negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # PID loop, TV6 is the exhaust moisture negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # Threshold of the PID loop;

[0046] For the water addition control 3 #PID loop, and the duration exceeds time4,

[0047] CV3 < TV7;

[0048] Wherein, CV3 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # The output value of the PID loop, TV7 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop;

[0049] For the exhaust negative pressure 4 # PID loop, and the duration exceeds time4,

[0050] CV4 < TV8;

[0051] Wherein, CV4 is the exhaust negative pressure 4 in the stable stage of the moisture control of the leaf conditioning machine # The output value of the PID, TV8 is the exhaust negative pressure 4 in the stable stage of the moisture control of the leaf conditioning machine # The threshold value of the PID.

[0052] Furthermore, the definition of the stable stage of the temperature control of the leaf conditioning machine further includes:

[0053] Keep the temperature of the material at the outlet of the leaf conditioning machine and the moisture of the material at the outlet of the leaf conditioning machine in a stable controlled state; keeping the temperature of the material at the outlet of the leaf conditioning machine and the moisture of the material at the outlet of the leaf conditioning machine in a stable controlled state includes the actual value Vtemp of the outlet material temperature real And the controlled required value Vtemp set The absolute value of the difference is kept lower than the threshold TV9, and the duration exceeds time5; the actual value Vmos of the outlet material moisture real And the controlled required value Vmos set The absolute value of the difference is kept lower than the threshold TV 10 , and the duration exceeds time5.

[0054] Furthermore, the definition formula of the stable stage of the temperature control of the leaf conditioning machine further includes:

[0055] |Vtemp real -Vtemp set | < TV9, and the duration exceeds time5;

[0056] |Vmos real -Vmos set | < TV 10 , and the duration exceeds time5;

[0057] Wherein, Vtemp real Is the actual value of the outlet material temperature, Vtempset is the controlled required value of the outlet material temperature, Vmos real is the actual value of the outlet material moisture, Vmos set is the controlled required value of the outlet material moisture.

[0058] Furthermore, the method for obtaining the material moisture control model of the silk reeling and leaf conditioning machine includes:

[0059] Give a fixed increment value to the output film valve opening value of the hot air temperature control PID loop and simulate it into a stable step signal;

[0060] Record the data of the actual value of the outlet material temperature changing with time t and fit it into a curve using a computer algorithm;

[0061] Calculate the parameter values in the transfer function of the first-order plus lag control model by back-calculating through the curve, and obtain an approximate first-order lag model. The approximate first-order lag model is the material temperature control model of the silk reeling and leaf conditioning machine;

[0062] The material temperature control model of the silk reeling and leaf conditioning machine is:

[0063]

[0064] In the formula, K is the static amplification coefficient, Ts is the time constant, τ is the model lag time, s is the Laplace transform factor, and Φ(s) is the transfer function of the material temperature control model of the silk reeling and leaf conditioning machine;

[0065] Among them,

[0066]

[0067]

[0068] In the formula, y(∞) is the steady-state value of the step response curve, f(t) is the ratio of the time characteristic function y(t) to the steady-state value y(∞) of the step response curve, A is the step disturbance increment value, t1 and t2 are two different time variables selected on the curve of the function f(t), and T is the time constant.

[0069] Compared with the prior art, the beneficial effects achieved by the present invention:

[0070] The present invention discloses a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making, defines the stable stage of the temperature control of the leaf conditioning machine in a formulaic form, effectively identifies the stage and application scenarios of a constant system that can be approximated as a linearized system, obtains an accurate mathematical model for the material temperature control of the leaf conditioning machine in the stable production stage, has good feasibility, can be carried out simultaneously with physical commissioning in the industry, does not waste tobacco material resources additionally, and has high accuracy. At the same time, due to the simplicity of the model and the small number of parameters, it is easy to modify the parameters later to correct the model again, effectively improving the stability, accuracy and rapidity of the material temperature control under specific production conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 is a flowchart of a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention;

[0072] Figure 2 is a schematic diagram of the conventional stage of the temperature control of the leaf conditioning machine in a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention;

[0073] Figure 3 is a schematic diagram of the stable stage of the temperature control of the leaf conditioning machine in a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention;

[0074] Figure 4 is a schematic diagram of an approximate single-loop process control in a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention;

[0075] Figure 5 is a schematic diagram of a step signal in a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention;

[0076] Figure 6 is a schematic diagram of the step response curve of constructing the function f(t) in a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making provided in Embodiment 1 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0077] The technical solution of the present invention will be described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific features in the embodiments of the present application and the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0078] In this text, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this text, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0079] As Figures 1 to 6 shown, this embodiment provides a method for experimentally obtaining a material temperature control model of a leaf conditioning machine for cigarette making, including the following steps:

[0080] Step 1: Enter the production stage when the leaf conditioning machine meets the production conditions;

[0081] First, determine whether the loose leaf conditioning machine starts production. If so, proceed to the next step; otherwise, continue to wait until the production conditions are met. Enter the production stage when the loose leaf conditioning machine meets the production conditions.

[0082] Step 2: Conduct temperature control on the leaf conditioning machine during the production stage, and define the stable stage of the leaf conditioning machine temperature control in a formulaic form;

[0083] Control the hot air temperature and process direct injection steam in the corresponding heat source control loop of the leaf conditioning machine using a single closed-loop negative feedback PID (Proportional Integral Derivative Controller). Also, control the water addition loop and exhaust negative pressure that have an indirect impact on the outlet material temperature in the leaf conditioning machine using a single closed-loop negative feedback PID. Define the set value SP in each PID control module as the preset set value (equipment parameter or recipe parameter) of each control loop during the production stage, as Figure 2 shown. The entire production process is carried out in a relatively stable feedback manner. When the outlet temperature sensor detects the material temperature value at the outlet, lock the hot air temperature that affects the outlet material temperature as the main heat source control loop, cancel the preset set value of the hot air control PID loop, and feed back the outlet material temperature value after conversion through a specific formula to the SP value of the hot air temperature PID control loop for closed-loop control, as Figure 3 shown.

[0084] Then, wait for the leaf conditioning machine temperature control to enter the stable stage. In this method, the definition of the stable stage of the leaf conditioning machine temperature control is: the hot air temperature 1 # in the PID loop and the process direct injection steam 2 # in the PID loop enter the temperature control stable state.

[0085] It should be noted that in this stage, define the thresholds TV1 to TV 10 , the thresholds TV1 to TV 10They are value range comparison type parameters respectively used to determine whether the device has entered the stable stage of temperature control of the conditioning machine, and are set by the user according to debugging experience. Among them, the threshold values TV1 and TV3 correspond to 1 # PID loop, and the threshold values TV2 and TV4 correspond to 2 # PID loop, and the threshold values TV5 and TV7 correspond to 3 # PID loop, and the threshold values TV6 and TV8 correspond to 4 # PID loop, and the threshold values TV9 and TV 10 correspond to the value related to the outlet moisture content.

[0086] Define the duration parameters time1 to time5. The duration parameters time1 to time5 are time length comparison type parameters respectively used to determine whether the device has entered the stable stage of temperature control of the conditioning machine, and are set by the user according to debugging experience. Among them, time1 corresponds to 1 # PID loop and 2 # the duration of the deviation value of the PID loop, and time2 corresponds to 1 # PID loop and 2 # the CV value of the PID loop, and time3 corresponds to 3 # PID loop and 4 # the duration of the deviation value of the PID loop, and time4 corresponds to 3 # PID loop and 4 # the CV value of the PID loop, and time5 corresponds to the value related to the outlet moisture content.

[0087] Among them, the hot air temperature within the time when the duration exceeds time1 # the absolute value of the difference between the set value SP1 and the actual value PV1 of the PID loop of 1 is kept lower than the threshold value TV1, and lasts for a corresponding period of time, and the process direct injection steam within the time when the duration exceeds time1 # the absolute value of the difference between the set value SP2 and the actual value PV2 of the PID loop of 2 is kept lower than the threshold value TV2, and lasts for a corresponding period of time.

[0088] The description based on the mathematical formula is:

[0089] For the hot air temperature 1 # PID loop, and the duration exceeds time1:

[0090] |SP1 - PV1| < TV1;

[0091] In the formula, PV1 is the actual value of the hot air temperature in the stable stage of temperature control of the conditioning machine, SP1 is the set value of the hot air temperature in the stable stage of temperature control of the conditioning machine, and TV1 is the threshold value of the hot air temperature 1 # PID loop.

[0092] For process direct injection steam 2 # PID loop and the duration exceeds time1:

[0093] |SP2 - PV2| < TV2;

[0094] Wherein, PV2 is the actual value of the process direct injection steam in the stable stage of the leaf moistening machine temperature control, SP2 is the set value of the process direct injection steam in the stable stage of the leaf moistening machine temperature control, and TV2 is the process direct injection steam 2 in the stable stage of the leaf moistening machine temperature control # Threshold value of the PID loop.

[0095] Meanwhile, the stable stage also needs to meet: keep the opening of the hot air temperature control diaphragm valve and the opening of the direct injection steam control diaphragm valve relatively stable; keep the water addition amount and the exhaust moisture negative pressure relatively stable.

[0096] The relatively stable opening of the hot air temperature control diaphragm valve includes hot air temperature 1 # The output value CV1 of the PID loop of hot air temperature 1 keeps lower than the threshold value TV3, and the relatively stable opening of the direct injection steam control diaphragm valve includes process direct injection steam 2 # The output value CV2 of the PID loop keeps lower than the threshold value TV4;

[0097] The relatively stable water addition amount and exhaust moisture negative pressure include water addition control 3 # PID loop and exhaust moisture negative pressure 4 # PID loop enters the temperature stable state;

[0098] The description based on mathematical formula is:

[0099] For hot air temperature 1 # PID loop and the duration exceeds time2,

[0100] CV1 < TV3;

[0101] Wherein, CV1 is the output value of the PID loop of hot air temperature 1 in the stable stage of the leaf moistening machine temperature control; TV3 is the hot air temperature 1 in the stable stage of the leaf moistening machine temperature control # Threshold value of the PID loop;

[0102] For process direct injection steam 2 # PID loop and the duration exceeds time2,

[0103] CV2 < TV4;

[0104] Wherein, CV2 is the process direct injection steam 2 in the stable stage of the leaf moistening machine temperature control #The output value of the PID loop; TV4 is the process direct injection steam 2 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop;

[0105] In addition, the water addition amount and the exhaust negative pressure that have an indirect impact on the temperature of the outlet material in the leaf conditioning machine also need to meet the stable conditions, that is: the water addition control loop 3 # The PID loop and the exhaust negative pressure 4 # The PID loop enters the temperature stable control state. Among them, the water addition control loop 3 within the time duration exceeding time3 # The absolute value of the difference between the set value SP3 and the actual value PV3 of the PID loop remains lower than the threshold value TV5 and lasts for a corresponding period of time. Similarly, the exhaust negative pressure 4 within the time duration exceeding time3 # The absolute value of the difference between the set value SP4 and the actual value PV4 of the PID loop remains lower than the threshold value TV6 and lasts for a corresponding period of time.

[0106] The description based on the mathematical formula is:

[0107] For the water addition control 3 # The PID loop, and the duration exceeds time3,

[0108] |SP3 - PV3| < TV5;

[0109] In the formula, SP3 is the set value of the water addition control 3#PID loop in the stable stage of the temperature control of the leaf conditioning machine; PV3 is the actual value of the water addition control 3#PID loop in the stable stage of the temperature control of the leaf conditioning machine; TV5 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop.

[0110] For the exhaust negative pressure 4 # The PID loop, and the duration exceeds time3,

[0111] |SP4 - PV4| < TV6;

[0112] In the formula, SP4 is the set value of the exhaust negative pressure 4#PID loop in the stable stage of the temperature control of the leaf conditioning machine # PV4 is the actual value of the exhaust negative pressure 4#PID loop in the stable stage of the temperature control of the leaf conditioning machine # TV6 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop.

[0113] The stable stage also needs to meet: the water addition control 3 within the time duration exceeding time4 #The output value CV3 of the PID loop remains below the threshold TV7 and lasts for a corresponding period of time, indicating that the water addition control loop controls the pump speed relatively stably; the exhaust negative pressure within the duration exceeding time4 # The output value CV4 of the PID loop remains below the threshold TV8 and lasts for a corresponding period of time, indicating that the opening of the exhaust negative pressure valve is relatively stable.

[0114] The description based on mathematical formula is:

[0115] For the water addition control 3 # For the PID loop, and the duration exceeds time4,

[0116] CV3 < TV7;

[0117] In the formula, CV3 is the output value of the water addition control 3 PID loop in the stable stage of the leaf moistening machine temperature control; TV7 is the threshold of the water addition control 3 PID loop in the stable stage of the leaf moistening machine temperature control # TV7 is the threshold of the water addition control 3 PID loop in the stable stage of the leaf moistening machine temperature control # TV7 is the threshold of the PID loop for water addition control 3

[0118] For the exhaust negative pressure 4 # For the PID loop, and the duration exceeds time4,

[0119] CV4 < TV8;

[0120] In the formula, CV4 is the output value of the PID for the exhaust negative pressure 4 in the stable stage of the leaf moistening machine moisture control; TV8 is the threshold of the PID for the exhaust negative pressure 4 in the stable stage of the leaf moistening machine moisture control # TV8 is the threshold of the PID for the exhaust negative pressure 4 in the stable stage of the leaf moistening machine moisture control # TV8 is the threshold of the PID for the exhaust negative pressure 4

[0121] In addition, the stable stage also needs to meet: the temperature and moisture of the material at the outlet of the leaf moistening machine are both in a stable controlled and small fluctuation state. It is required that the absolute value of the difference between the actual value Vtemp of the outlet material temperature real and the controlled required value Vtemp set remains below the threshold TV9 and lasts for a duration exceeding time5; the absolute value of the difference between the actual value Vmos of the outlet material moisture real and the controlled required value Vmos set remains below the threshold TV 10 and lasts for a duration exceeding time5.

[0122] The description based on mathematical formula is:

[0123] |VtemP real -Vtemp set | < TV9 and lasts for a duration exceeding time5;

[0124] |Vmosreal -Vmos set |<TV 10 and the duration exceeds time5;

[0125] In the formula, Vtemp real is the actual value of the outlet material temperature, Vtemp set is the controlled required value of the outlet material temperature, Vmos real is the actual value of the outlet material moisture, Vmos set is the controlled required value of the outlet material moisture.

[0126] Only when all the above conditions and mathematical formulas are satisfied simultaneously can it be defined as the stable stage of the temperature control of the leaf conditioning machine.

[0127] Step 3: When the temperature control of the leaf conditioning machine enters the stable stage, approximate the non-linear time-varying system as a linearized constant system to obtain the material temperature control model of the cigarette making leaf conditioning machine.

[0128] Only when entering the stable stage of the temperature control of the leaf conditioning machine can the non-linear time-varying system be approximated as a linearized constant system, and can the accurate control model linearized in the stable stage of temperature control be obtained through complex methods, that is, the material temperature control model of the cigarette making leaf conditioning machine.

[0129] Since in the previous steps, the hot air temperature 1#PID loop has been used as the only feedback control path for the outlet material temperature control, and the outlet material temperature value is directly fed back to the set value SP of the hot air temperature PID control loop. The diaphragm valve controlled by the output of the hot air temperature PID will directly control the height of the outlet material temperature. At this time, the entire outlet material temperature control of the leaf conditioning machine is simplified to a single process control, as shown in the box Figure 4 shown. Since the change of the outlet material temperature controlled by the output of the hot air temperature 1#PID loop is non-oscillatory, monotonic, has hysteresis (time delay) and inertia, and has self-balancing ability, it belongs to a self-regulating process. At the same time, based on considering the shape and characteristics of the step response curve of the outlet material temperature for the step response characteristic curve of the output of the hot air temperature diaphragm valve, this control process can be approximately obtained and accurately verified as a first-order lag model.

[0130] In the principle of automatic control, the transfer function of the first-order plus lag control model is:

[0131]

[0132] In the formula, K is the static amplification coefficient, Ts is the time constant, τ is the model lag time, s is the Laplace transform factor, and Φ(s) is the transfer function of the material temperature control model of the cigarette making leaf conditioning machine.

[0133] After performing the inverse Laplace transform, under the action of the step disturbance quantity A, its time characteristic function is as follows:

[0134]

[0135] In the formula, y(t) is the time characteristic function, and t is the time.

[0136] The general shape of its function curve is as shown in Figure 5 shown.

[0137] The method of the present invention simulates a stable step signal by giving a fixed increment value to the output film valve opening value of the hot air temperature control PID loop, records the data of the outlet material temperature Vtemp real changing with time t, and fits it into a curve using a computer algorithm. Through this curve, the three parameter values of K, T, and τ in the transfer function of the first-order plus lag control model are calculated in reverse, so as to obtain an approximate first-order lag model.

[0138] The specific method is as follows:

[0139] First, calculate the average value of the output film valve opening value of the hot air temperature control PID loop in the stable stage of the leaf conditioning machine temperature control Its calculation formula is:

[0140]

[0141] where n1 is the number of actual value data of the film valve opening value in the stable stage of the leaf conditioning machine temperature control, is the sum of the actual values of the film valve opening value, is the average value of the output film valve opening value of the hot air temperature control PID loop in the stable stage of the leaf conditioning machine temperature control.

[0142] Next, calculate the average value of the outlet material temperature in the stable stage of the leaf conditioning machine temperature control Its calculation formula is:

[0143]

[0144] In the formula, is the average value of the outlet material temperature in the stable stage of the leaf conditioning machine temperature control, n2 is the number of actual value data of the outlet material temperature in the stable stage of the leaf conditioning machine temperature control, is the sum of the actual values of the outlet material temperature.

[0145] If then a given increment P is given and accumulated to the value, and the hot air temperature 1 # PID loop is in the manual state, and the output CV1 value is always Simulate a step signal with a step quantity of P, and continuously and stably apply it to the output end of the system, as Figure 5 shown. Record the temperature of the outlet material Vtemp real ' data changing with time t, and calculate Vtemp real ' and the average value of the outlet material temperature at the stable stage of the temperature control of the leaf conditioning machine The difference is defined as the data y, and the definition formula of y is:

[0146]

[0147] In the formula, y is the difference between the outlet material temperature Vtemp real ' and the average value of the outlet material temperature at the stable stage of the temperature control of the leaf conditioning machine , Vtemp real ' is the outlet material temperature, is the average value of the outlet material temperature at the stable stage of the temperature control of the leaf conditioning machine.

[0148] According to the continuous action of the step signal, record the above y values, mark them on the coordinate with time t as the abscissa, and fit the curve. The general shape of the curve should be as shown in the figure. The method for calculating the three parameter values of K, T, and τ in the transfer function of the first-order plus lag control model is as follows:

[0149] Define the static amplification coefficient K as the ratio of the steady-state value y(∞) of the step response curve to the step disturbance increment value A, that is:

[0150]

[0151] In the formula, K is the static amplification coefficient, y(∞) is the steady-state value of the step response curve, and A is the step disturbance increment value.

[0152] Then define a function f(t), and let

[0153] Since the first-order lag model has self-balancing ability and belongs to a self-constant process. The step response must converge to a fixed value, which is defined as y(∞). Define the ratio of y(t) to y(∞) as the function f(t), then the formula of the function f(t) is:

[0154] Then

[0155] In the formula, f(t) is the ratio of the time characteristic function y(t) to the steady-state value y(∞) of the step response curve.

[0156] Such as Figure 6As shown in the figure, two different time variables t1 and t2 are selected on the curve, and their corresponding f(t) function values are f(t1) and f(t2). Among them, τ < t1 < t2.

[0157] From this, it can be obtained that:

[0158]

[0159] In the formula, f(t1) is the f(t) function value corresponding to the time variable t1, f(t2) is the f(t) function value corresponding to the time variable t2, and T is the time constant.

[0160] Taking the natural logarithm of both sides of the above equation, we get:

[0161]

[0162] By solving simultaneously, we obtain:

[0163]

[0164] Taking f(t1) = 0.3 and f(t2) = 0.7, we get:

[0165]

[0166] In order to verify the accuracy of the model and for the convenience of calculation, appropriate values of t3, t4, and t5 are selected for verification.

[0167] When t3 < τ, f(t3) = 0;

[0168] When t4 = 0.5T + τ, f(t4) = 0.39;

[0169] When t5 = T + τ, f(t5) = 0.63.

[0170] If the values of the standard curve at t3, t4, and t5 differ significantly from the above values, it indicates that the model error is too large, and the conditions and parameters for the stable stage of the temperature control of the leaf conditioning machine need to be re - determined until an accurate first - order lag transfer function can be obtained and pass the above verification.

[0171] Therefore, the transfer function of the material temperature control model of the leaf conditioning machine in silk reeling is:

[0172]

[0173] The values of the parameter K, the parameter T, and the parameter τ have all been obtained.

[0174] So far, the material temperature control model of the leaf conditioning machine in the special production stable mode has been obtained.

[0175] It should be noted that when using this method in the on-site test of Hangzhou Cigarette Factory, the effective parameter combinations are: TV1 = 2.0; TV2 = 3.0; TV3 = 7.0%; TV4 = 7.0%; TV5 = 2.0; TV6 = 0.15; TV7 = 7.0%; TV8 = 7.0%; TV9 = 0.5; TV10 = 0.5; time1 = 300s; time2 = 300s; time3 = 180s; time4 = 180s; time5 = 300s; A = 20%.

[0176] When verifying the accuracy of the above first-order lag model, if there are large errors, in addition to the need to re-determine the conditions in the stable stage of the temperature control of the leaf conditioning machine, the above parameters can also be re-adjusted, and then the test can be carried out again to obtain a new first-order lag model in the stable stage of the temperature control of the leaf conditioning machine after adjustment, and verify it again until the verification accuracy meets the requirements.

[0177] In summary, this embodiment provides a method for experimentally obtaining the material temperature control model of the cut tobacco leaf conditioning machine, defines the stable stage of the temperature control of the leaf conditioning machine in a formulaic form, effectively identifies the stage and application scenarios of a constant system that can be approximated as linearization, and obtains an accurate mathematical model for the material temperature control of the cut tobacco leaf conditioning machine in the stable production stage. It has good feasibility, can be carried out simultaneously with the physical commissioning in the industry, does not waste tobacco material resources additionally, and has high accuracy. At the same time, because the model is simple and has few parameters, it is easy to modify the parameters later to correct the model again. Based on the characteristics of this accurate mathematical model, control strategies such as time-delay Smith control, fuzzy control, neural network, adaptive control, and predictive control can be adopted to replace the original PID control of the equipment, so as to additionally obtain the stability, stability margin, accuracy, and time-domain fast response characteristics of the material temperature control model of the cut tobacco leaf conditioning machine, so as to further improve and correct the accurate mathematical model, and effectively improve the stability, accuracy, and rapidity of the material temperature control under specific production conditions.

[0178] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A method for experimentally obtaining a material temperature control model of a silk reeling and leaf conditioning machine, characterized in that, Including: Enter the production stage when the leaf conditioning machine meets the production conditions; During the production stage, conduct temperature control on the leaf conditioning machine, and define the stable stage of the temperature control of the leaf conditioning machine in a formulaic form; When the temperature control of the leaf conditioning machine enters the stable stage, approximate the non-linear time-varying system as a linearized constant system, and obtain the material temperature control model of the cigarette making leaf conditioning machine; The definition formula of the stable stage of the temperature control of the leaf conditioning machine includes: For hot air temperature 1 # PID loop, and the duration exceeds time1: ； Wherein, PV1 is the actual value of the hot air temperature in the stable stage of the temperature control of the leaf conditioning machine, SP1 is the set value of the hot air temperature in the stable stage of the temperature control of the leaf conditioning machine, and TV1 is the hot air temperature 1 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop; For process direct injection steam 2 # PID loop, and the duration exceeds time1: ； Wherein, PV2 is the actual value of the process direct injection steam in the stable stage of the temperature control of the leaf conditioning machine, SP2 is the set value of the process direct injection steam in the stable stage of the temperature control of the leaf conditioning machine, and TV2 is the process direct injection steam 2 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop.

2. The method for obtaining the material temperature control model of the silk reeling and leaf moistening machine according to claim 1, characterized in that, The temperature control of the leaf conditioning machine during the production stage includes: Use a PID control module to control the hot air temperature, process direct injection steam, water addition circuit, and moisture exhaust negative pressure in the heat source control circuit of the leaf conditioning machine; Define the set value SP in the PID control module as the preset set value of the heat source control circuit during the production stage, and the preset set value includes equipment parameters and / or recipe parameters.

3. The method for obtaining the material temperature control model of the leaf conditioning machine in the test according to claim 2, characterized in that, The temperature control of the leaf conditioning machine during the production stage further includes: When the outlet temperature sensor detects the material temperature value at the outlet, use the hot air temperature as the main heat source control circuit; the hot air temperature is used to control the outlet material temperature; Cancel the preset set value of the hot air control circuit, and feedback the material temperature value at the outlet to the set value SP of the hot air temperature PID control circuit through conversion by a specific formula for closed-loop control.

4. The method for obtaining the material temperature control model of the leaf conditioning machine in the test according to claim 3, characterized in that, The definition of the stable stage of the temperature control of the leaf conditioning machine includes: The hot air temperature 1 in the corresponding heat source control circuit of the leaf conditioning machine # The PID circuit and the process direct injection steam 2 # The PID circuit enters the temperature control stable state; Among them, the hot air temperature 1 within the time duration exceeding time1 # The absolute value of the difference between the set value SP1 and the actual value PV1 of the PID loop is lower than the threshold value TV1; Process direct injection steam 2 within a duration exceeding time1 # The absolute value of the difference between the setpoint SP2 and the actual value PV2 of the PID loop is lower than the threshold TV2; Process direct injection steam 2 within a duration exceeding time2 # The output value CV2 of the PID loop is lower than the threshold TV4.

5. The method for obtaining the material temperature control model of the silk-making leaf-conditioning machine according to claim 4, characterized in that The definition of the stable stage of the temperature control of the leaf conditioning machine further includes: Keep the opening degree of the hot air temperature control thin film valve and the opening degree of the direct injection steam control thin film valve relatively stable; keep the water addition amount and the moisture exhaust negative pressure relatively stable; The opening degree of the hot air temperature control thin film valve is relatively stable, including hot air temperature 1 # The output value CV1 of the PID loop remains lower than the threshold value TV3. The opening degree of the direct injection steam control thin film valve is relatively stable, including process direct injection steam 2 # The output value CV2 of the PID loop remains lower than the threshold value TV4; The relative stability of the maintained water addition amount and the moisture exhaust negative pressure includes water addition control 3 # PID loop and moisture exhaust negative pressure 4 # The PID loop enters a temperature stable state; Among them, the water addition control 3 within the time period with a duration exceeding time3 # The absolute value of the difference between the set value SP3 and the actual value PV3 of the PID loop remains lower than the threshold TV5; the exhaust negative pressure 4 within the time period with a duration exceeding time3 # The absolute value of the difference between the set value SP4 and the actual value PV4 of the PID loop remains lower than the threshold TV6; The keeping the water addition amount and the moisture exhaust negative pressure relatively stable further includes that the water addition control circuit controls the pump body speed relatively stable and the opening degree of the moisture exhaust negative pressure valve relatively stable; Among them, the water addition control 3 within the time period with a duration exceeding time4 # The output value CV3 of the PID loop remains lower than the threshold value TV7; the exhaust negative pressure 4 within the time period with a duration exceeding time4 # The output value CV4 of the PID loop remains lower than the threshold value TV8.

6. The method for obtaining the material temperature control model of the silk reeling and leaf conditioning machine according to claim 5, characterized in that The definition formula of the stable stage of the temperature control of the leaf conditioning machine further includes: For the hot air temperature 1 # PID loop, and the duration exceeds time2 ； Wherein, CV1 is the output value of the 1# PID loop of the hot air temperature during the stable stage of the temperature control of the leaf conditioning machine, and TV3 is the hot air temperature during the stable stage of the temperature control of the leaf conditioning machine # Threshold value of the PID loop; For process direct injection steam 2 # a PID loop and the duration exceeds time2 ； Wherein, CV2 is the output value of the process direct injection steam 2# PID loop in the stable stage of the temperature control of the leaf conditioning machine, and TV4 is the threshold value of the process direct injection steam 2 # PID loop; For water addition control 3 # a PID loop, and the duration exceeds time3 ； Wherein, SP3 is the set value of the 3# PID loop for water addition control in the stable stage of the temperature control of the leaf conditioning machine, PV3 is the actual value of the 3# PID loop for water addition control in the stable stage of the temperature control of the leaf conditioning machine, and TV5 is the water addition control 3 # threshold value of the PID loop; For the exhaust negative pressure 4 # PID loop, and the duration exceeds time3 ； In the formula, SP4 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # The set value of the PID loop, PV4 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # The actual value of the PID loop, TV6 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop; For water addition control 3 # a PID loop, and the duration exceeds time4 ； In the formula, CV3 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # The output value of the PID loop, and TV7 is the water addition control 3 in the stable stage of the temperature control of the leaf conditioning machine # The threshold value of the PID loop; For the exhaust negative pressure 4 # PID loop, and the duration exceeds time4 ； Wherein, CV4 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # the output value of PID, and TV8 is the exhaust negative pressure 4 in the stable stage of the temperature control of the leaf conditioning machine # the threshold value of PID.

7. The method for obtaining the material temperature control model of the silk-making leaf-conditioning machine according to claim 6, characterized in that, The definition of the stable stage of the temperature control of the leaf conditioning machine further includes: Keep the temperature of the material at the outlet of the leaf conditioning machine and the moisture content of the material at the outlet of the leaf conditioning machine in a stable and controlled state; the step of keeping the temperature of the material at the outlet of the leaf conditioning machine and the moisture content of the material at the outlet of the leaf conditioning machine in a stable and controlled state includes the actual value of the temperature of the outlet material and the controlled required value whose absolute value of the difference is kept lower than the threshold value TV9 and the duration exceeds time5; the actual value of the moisture content of the outlet material and the controlled required value whose absolute value of the difference is kept lower than the threshold value TV 10 and the duration exceeds time5.

8. The method for obtaining the material temperature control model of the silk reeling and leaf conditioning machine according to claim 7, characterized in that The definition formula of the stable stage of the temperature control of the leaf conditioning machine further includes: and the duration exceeds time5; and the duration exceeds time5; In the formula, is the actual value of the temperature of the outlet material, is the controlled required value of the temperature of the outlet material, is the actual value of the moisture content of the outlet material, is the controlled required value of the moisture content of the outlet material.

9. The method for obtaining the material temperature control model of the silk-making leaf-conditioning machine according to claim 8, wherein, The method for obtaining the material temperature control model of the cigarette making leaf conditioning machine includes: Give a fixed increment value to the output thin film valve opening value of the hot air temperature control PID circuit, and simulate it into a stable step signal; Record the data of the actual value of the outlet material temperature changing with time t, and fit it into a curve using a computer algorithm; Reverse calculate the parameter values in the transfer function of the first-order plus lag control model through the curve to obtain an approximate first-order lag model, and the approximate first-order lag model is the material temperature control model of the cigarette making leaf conditioning machine; The material temperature control model of the cigarette making leaf conditioning machine is: ； where K is the static amplification factor, Ts is the time constant, is the model lag time, s is the Laplace transform factor, is the transfer function of the material temperature control model of the silk reeling and leaf conditioning machine; Wherein, ； ； ； In the formula, is the steady-state value of the step response curve, f(t) is the ratio of the time characteristic function y(t) to the steady-state value of the step response curve , A is the step disturbance increment value, t1 and t2 are two different time variables selected on the curve of the function f(t), and T is the time constant.

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