Rice drying process dynamic control method and system giving consideration to energy efficiency and quality

Abstract

The invention discloses a rice drying process dynamic control method and system giving consideration to energy efficiency and quality. The method comprises the steps that the target water content X0 and the drying time end point t0 are set; discretizing a time interval [0, t0] into N nodes; setting an initial value of a node parameter for each node; performing interpolation processing based on the nodes to obtain a continuous control track; solving the water content corresponding to the t moment based on a preset differential equation; adjusting node parameters corresponding to each node on the basis of an optimization algorithm to minimize an objective function of the optimization algorithm to obtain optimized node parameters, generating a control curve through interpolation, and changing microwave power and hot air temperature in real time on the basis of the control curve to dry the rice. According to the method, the dynamic control track is generated through discretization of the time interval and piecewise linear interpolation, the microwave power and the hot air temperature are adjusted in combination with the drying rate differential equation and the multi-objective optimization algorithm, and the optimal balance between energy efficiency and quality in the rice drying process is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of rice drying control, and in particular to a method and system for dynamically controlling a rice drying process that takes both energy efficiency and quality into consideration. Background Art

[0002] After rice is harvested, it needs to be dried before being stored. Currently, the equipment used for drying rice is generally microwave hot air equipment, which has the following disadvantages:

[0003] 1) Microwave and hot air combined drying has high energy consumption, and microwaves consume a lot of energy;

[0004] 2) Production control methods often rely on experience and fixed process parameters, without a better control strategy;

[0005] 3) The optimization problem mainly stays in the response surface analysis and the solution of solving the maximum value, which has a single idea and does not achieve the best effect;

[0006] In the prior art, patent CN 116499205 A provides a method and device for intelligent grain drying based on a microwave heat pump. The core solution of this patent is to determine the type of grain by detecting its initial moisture content and bulk density. Based on the preset optimal drying model corresponding to different types and moisture contents (combined with microwave power and hot air temperature), microwave heat pump combined drying is used to ensure the lowest cracking rate and the highest polished rice rate. At the same time, the heat pump is used to recover the waste heat of the exhaust gas, thereby achieving intelligent drying with high efficiency, energy saving and controllable quality. This patent requires pre-storage of multiple target drying models, and the optimal drying model is rotated based on the material type and moisture content. The target drying model is obtained by screening according to the cracking rate and polished rice rate from multiple candidate drying models with different microwave powers and different hot air temperatures. That is, the applicability of the drying model in this patent is poor. For some crops and moisture contents, it may not be possible to screen out a suitable target drying model. Moreover, the patent does not disclose the specific content of the target drying model. Summary of the Invention

[0007] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method and system for dynamic control of the rice drying process that takes into account both energy efficiency and quality. The method aims to obtain the change trajectory equation of the factors affecting drying through program calculation, and can dry rice under continuously changing conditions to achieve the optimal effect of quality and energy efficiency. The control method and system of the present invention are universal.

[0008] Technical Solution: To achieve the above objectives, the present invention provides a method for dynamically controlling a rice drying process that takes into account both energy efficiency and quality. The method is implemented by a controller and includes:

[0009] Set the target moisture content X0 and the drying time end t0; the target moisture content X0 and the drying time end t0 can be set according to the user's input data;

[0010] Discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P i With hot air temperature T i , i=1,2,…,N; here P i With T i It is an empirical value or a predicted value of uniform distribution;

[0011] Interpolation processing is performed based on the nodes to obtain a continuous control trajectory, which can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time. Through the above discretization and interpolation processing, P(t) and T(t) can be made continuous at the nodes;

[0012] Based on the following differential equation, solve the water content X(t) corresponding to time t:

[0013]

[0014] Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k=aP(t)+bT(t)+c, a, b, c are constants;

[0015] Adjust each node t based on the optimization algorithm i Corresponding node parameter P i With T i , so that the objective function of the optimization algorithm is minimized and the optimized node parameters are obtained; the objective function is:

[0016] J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ;

[0017] Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency;

[0018] The optimized node parameters are interpolated to generate a control curve, and the microwave power and hot air temperature are changed in real time based on the control curve to dry the rice.

[0019] Furthermore, the quality parameter q includes a cracking index SCI, which is expressed as follows:

[0020] SCI=0.0943T 2-7.5856T+148.99+14.861lnP-0.938+3.611;

[0021] Wherein, P and T represent the specific values ​​of microwave power and hot air temperature respectively.

[0022] Furthermore, the functional relationship between drying parameters and energy efficiency is expressed as:

[0023]

[0024] Furthermore, interpolation processing is performed based on the nodes to obtain a continuous control trajectory, specifically:

[0025] Use linear interpolation rule to interpolate adjacent nodes t i and t i+1 The node parameters of the interval between are interpolated, and the interpolation formula is as follows:

[0026]

[0027] Furthermore, in the optimization algorithm, a parameter for the microwave power P of the node is set. i With hot air temperature T i constraints, as well as constraints on quality parameter q and energy efficiency η.

[0028] Furthermore, the control curve is generated by interpolation based on the optimized node parameters, specifically:

[0029] Use linear interpolation rule to interpolate adjacent nodes t i and t i+1 The node parameters in the interval between are interpolated.

[0030] A dynamic control system for rice drying process that takes into account both energy efficiency and quality, the system includes:

[0031] The setting module is used to set the target moisture content X0 and the drying time end t0;

[0032] Discretization and parameter setting module, which is used to discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P i With hot air temperature T i , i=1,2,…,N;

[0033] An interpolation module, which is used to perform interpolation processing based on the nodes to obtain a continuous control trajectory, wherein the control trajectory can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time;

[0034] A solution module is used to solve the water content X(t) corresponding to time t based on the following differential equation:

[0035]

[0036] Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k=aP(t)+bT(t)+c, a, b, c are constants;

[0037] Optimization module, adjusts each node t based on the optimization algorithm i Corresponding node parameter P i With T i , so that the objective function of the optimization algorithm is minimized and the optimized node parameters are obtained; the objective function is:

[0038] J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ;

[0039] Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency;

[0040] The control module interpolates and generates a control curve based on the optimized node parameters, and changes the microwave power and hot air temperature in real time based on the control curve to dry the rice.

[0041] Beneficial effects: The method and system for dynamically controlling the rice drying process while taking into account both energy efficiency and quality of the present invention have the following beneficial effects:

[0042] The present invention generates dynamic control trajectories through discretized time intervals and piecewise linear interpolation, and combines the drying rate differential equation with a multi-objective optimization algorithm to adjust the microwave power and hot air temperature, so that the rice drying process achieves an optimal balance between energy efficiency and quality. At the same time, the final moisture content is accurately controlled to the target value. The algorithm is highly adaptable and can be quickly transplanted to different drying systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 Schematic diagram of the process of dynamic control of rice drying process to balance energy efficiency and quality;

[0044] Figure 2 The trajectory diagram of the optimized microwave power and hot air temperature changing with time;

[0045] Figure 3 Schematic diagram of the dynamic control system for rice drying process that takes into account both energy efficiency and quality. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the accompanying drawings.

[0047] like Figure 1 The dynamic control method for rice drying process that takes into account both energy efficiency and quality is shown. The method is implemented by a controller and includes steps S1-S4:

[0048] Step S1, setting the target moisture content X0 and the drying time end t0; the target moisture content X0 and the drying time end t0 can be set according to the user's input data;

[0049] In this embodiment, the target moisture content X0 = 13.5%, and the drying time end point t0 = 3600s;

[0050] Step S2: discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P i With hot air temperature T i , i=1,2,…,N; here P i With T i It is an empirical value or a predicted value of uniform distribution;

[0051] In this embodiment, the time interval [0,3600] is divided into 18 segments, that is, discretized into 19 nodes;

[0052] Step S3: performing interpolation processing based on the nodes to obtain a continuous control trajectory, which can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time. Through the above discretization and interpolation processing, P(t) and T(t) can be made continuous at the nodes;

[0053] Step S4: Solve the water content X(t) corresponding to time t based on the following differential equation:

[0054]

[0055] Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k = aP(t) + bT(t), a, b, c are constants;

[0056] In this embodiment, the drying coefficient corresponding to rice is k=0.0036P(t)+0.00005T(t)+0.00115;

[0057] Step S5: Adjust each node t based on the optimization algorithm i Corresponding node parameter P i With T i, so that the objective function of the optimization algorithm is minimized and the optimized node parameters are obtained; the objective function is:

[0058] J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ;

[0059] Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency;

[0060] In this embodiment, X(t0) or X(3600) is the calculated value of the final moisture content obtained after the continuous action of P(t) and T(t) that change with time. The goal of the above optimization algorithm is to minimize J.

[0061] Step S6: interpolating the optimized node parameters to generate a control curve, and changing the microwave power and hot air temperature in real time based on the control curve to dry the rice.

[0062] The present invention generates dynamic control trajectories through discretized time intervals and piecewise linear interpolation, and combines the drying rate differential equation with a multi-objective optimization algorithm to adjust the microwave power and hot air temperature, so that the rice drying process achieves an optimal balance between energy efficiency and quality. At the same time, the final moisture content is accurately controlled to the target value. The algorithm is highly adaptable and can be quickly transplanted to different drying systems.

[0063] Preferably, the quality parameter q includes a cracking waist index SCI, which is expressed as follows:

[0064] SCI=0.0943T 2 -7.5856T+148.99+14.861lnP-0.938+3.611;

[0065] Wherein, P and T represent the specific values ​​of microwave power and hot air temperature respectively; the above specific constant values ​​are obtained through experiments.

[0066] Preferably, the functional relationship between drying parameters and energy efficiency is expressed as:

[0067]

[0068] The above specific constant values ​​are obtained through experiments.

[0069] Preferably, the interpolation processing based on the nodes in the above step S3 is performed to obtain a continuous control trajectory, specifically:

[0070] Use linear interpolation rule to interpolate adjacent nodes t i and t i+1The node parameters of the interval between are interpolated, and the interpolation formula is as follows:

[0071]

[0072] Using linear interpolation, the overall control trajectory is in the form of a piecewise function, which can make both P(t) and T(t) continuous in the interval [0, t0], but the derivative is discontinuous. This function form can be solved piecewise when solving X(t0) or X(3600), which has high solution efficiency and can reduce the dimension of optimization variables in optimization calculations.

[0073] Preferably, in the optimization algorithm described in step S5 above, a parameter for the microwave power P of the node is set. i With hot air temperature T i Constraints for the quality parameter q and energy efficiency η. For example, you can set: P i ∈[300,800]W;T i ∈[40,70]℃; SCI≤15; η≥65%, etc.

[0074] Preferably, the interpolation based on the optimized node parameters in step S6 to generate the control curve is specifically as follows:

[0075] Use linear interpolation rule to interpolate adjacent nodes t i and t i+1 The node parameters of the interval between are interpolated. The specific interpolation formula is shown in the interpolation formula of step S3 above, which will not be described here.

[0076] The present invention also provides a dynamic control system for a rice drying process that balances energy efficiency and quality. The dynamic control system for a rice drying process may include or be divided into one or more program modules. One or more program modules are stored in a storage medium and executed by one or more processors to complete the present invention and implement the above-mentioned dynamic control method for a rice drying process that balances energy efficiency and quality. The program module referred to in the embodiment of the present invention refers to a series of computer program instruction segments that can perform specific functions. It is more suitable for describing the execution process of the dynamic control method for a rice drying process in a storage medium than the program itself. The following description will specifically introduce the functions of each program module of this embodiment. The system includes:

[0077] Setting module 701, which is used to set the target moisture content X0 and the drying time end t0;

[0078] Discretization and parameter setting module 702 is used to discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P iWith hot air temperature T i , i=1,2,…,N;

[0079] An interpolation module 703 is configured to perform interpolation processing based on the nodes to obtain a continuous control trajectory, wherein the control trajectory can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time;

[0080] The solution module 704 is used to solve the water content X(t) corresponding to time t based on the following differential equation:

[0081]

[0082] Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k=aP(t)+bT(t)+c, a, b, c are constants;

[0083] Optimization module 705, adjusts each node t based on the optimization algorithm i Corresponding node parameter P i With T i , so that the objective function of the optimization algorithm is minimized and the optimized node parameters are obtained; the objective function is:

[0084] J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ;

[0085] Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency;

[0086] The control module 706 generates a control curve by interpolation based on the optimized node parameters, and changes the microwave power and hot air temperature in real time based on the control curve to dry the rice.

[0087] Other contents of realizing the above-mentioned rice drying process dynamic control method based on the rice drying process dynamic control system have been described in detail in the previous embodiments. Please refer to the corresponding contents in the previous embodiments and will not be repeated here.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for dynamically controlling the rice drying process while taking into account both energy efficiency and quality, characterized in that: include: Set the target moisture content X0 and the drying time end point t0; Discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P i With hot air temperature T i , i=1,2,…,N; Interpolation processing is performed based on the nodes to obtain a continuous control trajectory, which can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time; Based on the following differential equation, solve the water content X(t) corresponding to time t: Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k=aP(t)+bT(t)+c, a, b, c are constants; Adjust each node t based on the optimization algorithm i The corresponding node parameters are used to minimize the objective function of the optimization algorithm and obtain the optimized node parameters; the objective function is: J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ; Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency; The optimized node parameters are interpolated to generate a control curve, and the microwave power and hot air temperature are changed in real time based on the control curve to dry the rice.

2. The method for dynamic control of rice drying process taking into account both energy efficiency and quality according to claim 1, characterized in that: The quality parameter q includes the cracking index SCI, which is expressed as follows: SCI=0.0943T 2 -7.5856T+148.99+14.861lnP-0.938+3.611; Wherein, P and T represent the specific values ​​of microwave power and hot air temperature respectively.

3. The method for dynamic control of rice drying process taking into account both energy efficiency and quality according to claim 1, characterized in that: The functional relationship between drying parameters and energy efficiency is expressed as:

4. The method for dynamic control of rice drying process taking into account both energy efficiency and quality according to claim 1, characterized in that: Interpolation processing is performed based on the nodes to obtain a continuous control trajectory, specifically: Use linear interpolation rule to interpolate adjacent nodes t i and t i+1 The node parameters of the interval between are interpolated, and the interpolation formula is as follows:

5. The method for dynamic control of rice drying process taking into account both energy efficiency and quality according to claim 1, characterized in that: In the optimization algorithm, the microwave power P of the node parameter is set. i With hot air temperature T i constraints, as well as constraints on quality parameter q and energy efficiency η.

6. The method for dynamic control of rice drying process taking into account both energy efficiency and quality according to claim 1, characterized in that: The interpolation based on the optimized node parameters is performed to generate the control curve, specifically: Use linear interpolation rule to interpolate adjacent nodes t i and t i+1 The node parameters in the interval between are interpolated.

7. A dynamic control system for rice drying process that takes into account both energy efficiency and quality, characterized in that the system include: The setting module is used to set the target moisture content X0 and the drying time end t0; Discretization and parameter setting module, which is used to discretize the time interval [0, t0] into N nodes, N ≥ 10; for each node t i Set the initial value of the node parameters, including the microwave power P i With hot air temperature T i , i=1,2,…,N; An interpolation module, which is used to perform interpolation processing based on the nodes to obtain a continuous control trajectory, wherein the control trajectory can reflect the microwave power P(t) and hot air temperature T(t) corresponding to any time; A solution module is used to solve the water content X(t) corresponding to time t based on the following differential equation: Among them, X e is the moisture content at the final equilibrium; k is the drying rate coefficient, and k=aP(t)+bT(t)+c, a, b, c are constants; Optimization module, adjusts each node t based on the optimization algorithm i The corresponding node parameters are used to minimize the objective function of the optimization algorithm and obtain the optimized node parameters; the objective function is: J=w1(X(t0)-X0) 2 +w2·q+w3(η-1) 2 ; Where, (X(t0)-X0) 2 represents the final moisture content deviation; q represents the quality parameter; η is the energy efficiency; The control module interpolates and generates a control curve based on the optimized node parameters, and changes the microwave power and hot air temperature in real time based on the control curve to dry the rice.

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