PID parameter tuning method, system, device and medium based on phase analysis

Abstract

The application relates to a PID parameter setting method, system, device and medium based on phase analysis, which comprises the following steps: acquiring historical trend values and PID initial parameters of PV parameters, SV parameters and MV parameters in a control loop; performing phase analysis processing on each parameter according to a trend graph constructed by the historical trend values, so as to obtain phase feature points corresponding to each parameter and step change information of the SV parameters; when the SV parameters have step changes, adjusting the proportionality and integral time of the PID initial parameters according to the overshoot and the rise time obtained from the phase feature points of the PV parameters and the SV parameters; and when the SV parameters do not have step changes, adjusting the proportionality and integral time of the PID initial parameters according to the integral judgment index and the proportional judgment index obtained from the phase feature points of the PV parameters and the MV parameters. The application improves the setting speed and accuracy of the PID parameters and improves the application range of the PID setting software.

Description

Technical Field

[0001] This invention relates to the field of industrial control technology, and in particular to a PID parameter tuning method, system, device and medium based on phase analysis. Background Technology

[0002] In today's industrial production, PID control remains the most widely used regulator control law. Since its invention, the PID controller has become one of the main technologies in industrial control due to its advantages such as simple structure, high stability, reliable operation, and convenient adjustment. Statistics show that over 90% of controllers in industrial production use PID controllers. However, despite the different adjustment requirements exhibited under different controlled objects and processes, accurate tuning of the PID parameters remains crucial to ensure the controller achieves optimal performance.

[0003] Existing PID parameter tuning methods include model-based tuning and empirical methods. Model-based tuning methods often rely on a large amount of control loop operating data and step test calculations. However, in the actual engineering application of PID tuning software, problems such as insufficient loop excitation and insufficient data source length frequently occur, making it impossible for model-based tuning methods to accurately tune the results. If model-based tuning methods are still used, it will inevitably consume more time and effort. Therefore, the accuracy of PID parameter tuning is also limited by the accuracy of the model, and it is often unsuitable for large-scale PID parameter tuning. Empirical tuning is suitable for process industries, but it requires too much technical skill from operators. Many companies lack experienced technicians, and inexperienced operators cannot guarantee the predicted effect of control parameters or the stable state of process industry production. Its operation is not suitable for most users.

[0004] Therefore, how to achieve high-precision PID parameter tuning in control loops with insufficient data sources is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a PID parameter tuning method, system, device and medium based on phase analysis, which solves the technical problem of low accuracy of PID parameter tuning in control loops with insufficient data sources.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] In a first aspect, embodiments of the present invention provide a PID parameter tuning method based on phase analysis, comprising:

[0010] The operating data of the control loop is preprocessed to obtain the historical trend value and PID initial parameters within a set time period. The historical trend value includes PV parameters, SV parameters and MV parameters.

[0011] A trend graph of the historical trend values ​​is constructed according to the time sequence, and phase analysis is performed on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter.

[0012] When the SV parameter has a step change, the proportional gain and integral time in the PID initial parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters to obtain the PID parameters.

[0013] When the SV parameter does not have a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral and proportional gain obtained from the phase characteristic points of the PV and MV parameters to obtain the PID parameters.

[0014] Optionally, the phase feature points include:

[0015] The starting point of the SV parameter change is the point where the SV parameter undergoes a step change in the trend graph.

[0016] PV parameter peaks are the peak points of each fluctuation in the PV parameter curve in the trend chart.

[0017] The PV parameter zero point is the first point in the trend chart where the PV parameter curve and the SV parameter curve are equal in value when the SV parameter does not change abruptly, or the PV parameter zero point is the first point in the trend chart where the PV parameter and the SV parameter are equal after the SV parameter undergoes abrupt change.

[0018] MV parameter troughs are the trough points of each fluctuation in the MV parameter curve in the trend chart.

[0019] Optionally, when the SV parameter exhibits a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters, resulting in PID parameters including:

[0020] When the SV parameter has a step change, the overshoot and rise time are obtained based on the phase characteristic points of the PV and SV parameters.

[0021] Determine whether the rise time meets the set first threshold range;

[0022] If the rise time is greater than 0.9 times the target rise time and less than 1.1 times the target rise time, then maintain the proportionality in the initial PID parameters.

[0023] If the rise time is less than 0.9 times the target rise time or greater than 1.1 times the target rise time, the proportional gain in the PID initial parameters is adjusted according to the rise time, and it is determined whether the overshoot meets the set second threshold range.

[0024] If the overshoot is greater than 0.8 and less than 1.1, then the integral time in the PID initial parameters is maintained.

[0025] If the overshoot is greater than 1.1 and the rise time is less than 0.9 times the target rise time, or if the overshoot is in the range of 0 to 0.8 and the rise time is greater than 1.1 times the target rise time, then the integral time in the PID initial parameters will be adjusted according to the overshoot.

[0026] Optionally, the formula for obtaining the overshoot is:

[0027] Overshoot = |PV max -SV new | / ΔSV*100% (1)

[0028] In equation (1), Overshoot represents the overshoot, PV max SV represents the peak value of the first PV parameter after a step change in the SV parameter. new ΔSV represents the parameter value after a step change in the SV parameter, and ΔSV represents the magnitude of the step change in the SV parameter.

[0029] The formula for obtaining the rise time is:

[0030] RiseTime = |T1 - T2| (2)

[0031] In equation (2), RiseTime represents the rise time, T1 represents the first moment when the PV parameter reaches its peak after the SV parameter undergoes a step change, and T2 represents the starting moment when the SV parameter undergoes a step change.

[0032] The adjustment formula for adjusting the proportional gain in the PID initial parameters based on the rise time is as follows:

[0033]

[0034] In equation (3), PB′ represents the adjusted proportional gain, Ks represents the iteration coefficient, Tss represents the steady-state time, which is equal to the time interval between two adjacent peaks in the PV parameters, and PB represents the proportional gain in the initial parameters of the PID.

[0035] The adjustment formula for adjusting the integral time in the PID initial parameters based on the overshoot is as follows:

[0036]

[0037] In equation (4), Ti′ represents the adjusted integral time, and Ti represents the integral time in the initial parameters of the PID.

[0038] Optionally, when the SV parameter does not exhibit a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral and proportional gain indicators obtained from the phase characteristic points of the PV and MV parameters, resulting in PID parameters including:

[0039] When the SV parameter does not have a step change, the integral judgment index and the proportional judgment index are obtained based on the phase characteristic points of the PV parameter and the MV parameter.

[0040] Determine whether the integral judgment index meets the set third threshold range;

[0041] If the integral judgment index is less than 0.4 and greater than 0.1, then the integral time in the PID initial parameters is maintained.

[0042] If the integral judgment index is greater than 0.4 or less than 0.1, the integral time in the PID initial parameters will be adjusted according to the integral judgment index, and it will be determined whether the proportional judgment index meets the set fourth threshold range.

[0043] If the proportional judgment index is greater than 0.225 times the steady-state time and less than 0.275 times the steady-state time, then the proportionality in the initial PID parameters is maintained.

[0044] If the proportional judgment index is less than 0.225 times the steady-state time and the integral judgment index is less than 0.1, or if the proportional judgment index is greater than 0.275 times the steady-state time and the integral judgment index is greater than 0.4, then the proportionality in the initial parameters of the PID controller will be adjusted according to the proportional judgment index.

[0045] Optionally, the formula for obtaining the integral judgment index is:

[0046]

[0047] In equation (5), Ki represents the integral judgment index, T1′ represents the first moment when the PV parameter reaches its peak within the set time period, T2′ represents the first moment when the PV parameter curve and the SV parameter curve are equal within the set time period, and T3′ represents the first moment when the MV parameter reaches its trough within the set time period.

[0048] The formula for obtaining the ratio judgment index is:

[0049] Kp=|T2′-T1′| (6)

[0050] In equation (6), Kp represents the integral judgment index;

[0051] The adjustment formula for adjusting the integral time in the PID initial parameters based on the integral judgment index is as follows:

[0052]

[0053] In equation (7), Ti′ represents the adjusted integral time, Ti represents the integral time in the initial parameters of the PID, Tss represents the steady-state time, the steady-state time is equal to the time interval between two adjacent peaks in the PV parameters, and e represents the natural constant.

[0054] The adjustment formula for adjusting the proportional gain in the initial parameters of the PID based on the proportionality judgment index is as follows:

[0055]

[0056] In equation (8), PB′ represents the adjusted proportional gain, and PB represents the proportional gain in the initial parameters of the PID controller.

[0057] Optionally, it also includes:

[0058] The PID parameters are written into the control loop, and it is determined whether the deviation between the PV parameters and SV parameters of the control loop is greater than the set deviation threshold.

[0059] If the deviation between the PV parameter and the SV parameter of the control loop is greater than the set deviation threshold, then it is determined that the PID parameter needs to be tuned a second time.

[0060] If the deviation between the PV parameter and the SV parameter of the control loop is not greater than the set deviation threshold, then the PID parameter tuning is considered complete.

[0061] Secondly, embodiments of the present invention also provide a PID parameter tuning system based on phase analysis, comprising:

[0062] The preprocessing module is used to preprocess the operating data of the control loop to obtain historical trend values ​​and PID initial parameters within a set time period. The historical trend values ​​include PV parameters, SV parameters and MV parameters.

[0063] The phase analysis module is used to construct a trend graph of the historical trend values ​​according to the time sequence, and to perform phase analysis processing on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter.

[0064] The first PID parameter tuning module is used to adjust the proportional gain and integral time in the initial PID parameters based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters when there is a step change in the SV parameter, so as to obtain the PID parameters.

[0065] The second PID parameter tuning module is used to adjust the proportional gain and integral time in the initial PID parameters based on the integral judgment index and proportional judgment index obtained from the phase characteristic points of the PV and MV parameters when there is no step change in the SV parameter, so as to obtain the PID parameters.

[0066] Thirdly, embodiments of the present invention also provide an electronic device, comprising:

[0067] processor;

[0068] The memory stores the steps of the PID parameter tuning method based on phase analysis described above for controlling the processor.

[0069] Fourthly, embodiments of the present invention also provide a computer-readable medium having computer-executable instructions stored thereon, wherein the executable instructions, when executed by a processor, implement the steps of the PID parameter tuning method based on phase analysis described above.

[0070] (III) Beneficial Effects

[0071] The beneficial effects of this invention are as follows: The PID parameter tuning method based on phase analysis proposed in this invention first analyzes and judges the operating data such as PV, SV, and MV parameters in the control loop, constructs historical trend graphs for each parameter, and then uses the phase characteristic points in the historical trend graphs to analyze the loop characteristics of the overshoot and rise time of the PID control system's step response, thereby providing a suitable PID parameter adjustment strategy. Compared with existing technologies, this method accelerates the PID parameter tuning speed and improves the applicability and tuning accuracy of PID tuning software.

[0072] Meanwhile, this invention uses the phase characteristic points of each operating parameter in the control loop to determine the phase difference caused by the integral time and proportional time of the control loop, thereby determining the adjustment direction of the control loop. Compared with the prior art, it improves the applicability of the PID parameter tuning method in the process industry and enhances the flexibility of using the PID parameter tuning method. Attached Figure Description

[0073] Figure 1 This is a flowchart illustrating a PID parameter tuning method based on phase analysis, provided in an embodiment of the present invention.

[0074] Figure 2This is a trend diagram of phase characteristic points in a PID control loop provided by an embodiment of the present invention when the SV parameter undergoes a step change;

[0075] Figure 3 This is a trend diagram of phase characteristic points in a PID control loop provided by an embodiment of the present invention when the SV parameter does not change abruptly.

[0076] Figure 4 This is a flowchart illustrating step S3 in a PID parameter tuning method based on phase analysis provided in an embodiment of the present invention.

[0077] Figure 5 A flowchart illustrating step S4 in a PID parameter tuning method based on phase analysis provided in an embodiment of the present invention.

[0078] Figure 6 A schematic diagram of a PID parameter tuning system based on phase analysis provided in an embodiment of the present invention;

[0079] Figure 7 This is a schematic diagram of the structure of a computer system for an electronic device according to an embodiment of the present invention;

[0080] Figure 8 The present invention provides an algorithm flowchart for a PID parameter tuning method based on phase analysis in one embodiment.

[0081] [Explanation of Labels in the Attached Image]

[0082] 300: PID parameter tuning system; 301: Preprocessing module; 302: Phase analysis module; 303: First PID parameter adjustment module; 304: Second PID parameter adjustment module;

[0083] 400: Computer system; 401: CPU; 402: ROM; 403: RAM; 404: Bus; 405: I / O interface; 406: Input section; 407: Output section; 408: Storage section; 409: Communication section; 410: Driver; 411: Removable media. Detailed Implementation

[0084] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0085] refer to Figure 1-8As shown in the embodiments of the present invention, a PID parameter tuning method, system, device, and medium based on phase analysis are proposed. The PID parameter tuning method includes: preprocessing the operating data of the control loop to obtain historical trend values ​​and initial PID parameters within a set time period. The historical trend values ​​include PV parameters, SV parameters, and MV parameters. A trend graph of the historical trend values ​​is constructed according to the time sequence, and phase analysis processing is performed on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points corresponding to each parameter and the step change information of the SV parameter. When there is a step change in the SV parameter, the proportional gain and integral time in the initial PID parameters are adjusted based on the overshoot and rise time obtained from the phase feature points of the PV and SV parameters to obtain the PID parameters. When there is no step change in the SV parameter, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral judgment index and proportional judgment index obtained from the phase feature points of the PV and MV parameters to obtain the PID parameters.

[0086] This embodiment proposes a PID parameter tuning method based on phase analysis. First, it analyzes and judges the operating data such as PV, SV, and MV parameters in the control loop, constructing historical trend graphs for each parameter. Then, it uses phase characteristic points in the historical trend graphs to analyze the loop characteristics of the PID control system's step response, including overshoot and rise time, thereby providing a suitable PID parameter adjustment strategy. Compared to existing technologies, this method accelerates PID parameter tuning speed and improves the applicability and accuracy of PID tuning software.

[0087] Meanwhile, this embodiment uses the phase characteristic points of each operating parameter in the control loop to determine the phase difference caused by the integral time and proportional time of the control loop, thereby determining the adjustment direction of the control loop. Compared with the prior art, it improves the applicability of the PID parameter tuning method in the process industry and increases the flexibility of using the PID parameter tuning method.

[0088] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0089] Specifically, refer to Figure 1 As shown, one embodiment of the present invention proposes a PID parameter tuning method based on phase analysis, which includes:

[0090] S1. Preprocess the operating data of the control loop to obtain the historical trend value and PID initial parameters within a set time period. The historical trend value includes PV parameters, SV parameters and MV parameters.

[0091] In this embodiment, the type of control loop to be tuned is obtained by preprocessing the operating data of the control loop to be tuned. The control loops include: temperature control loop (TIC), pressure control loop (PIC), level control loop (LIC), flow control loop (FIC), and other analyzer control loops (AIC). Then, based on the type of control loop to be tuned and combined with the preprocessed operating data, the historical trend value and PID initial parameters of the control loop to be tuned within a set time period are obtained. The historical trend values ​​include: PV parameter (measured value), SV parameter (set value), and MV parameter (output value).

[0092] S2. Construct a trend chart of historical trend values ​​according to the time sequence, and perform phase analysis on each parameter of the historical trend values ​​in the trend chart to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter.

[0093] To further explain, the phase characteristic points include: the starting point of SV parameter change, the peak of PV parameter, the zero point of PV parameter, and the trough of MV parameter. The starting point of SV parameter change is the point where the SV parameter undergoes a step change in the trend chart; the peak of PV parameter is the peak point of each fluctuation of the PV parameter curve in the trend chart; the zero point of PV parameter is the first point where the PV parameter curve and the SV parameter curve are equal in value when there is no step change in the SV parameter in the trend chart, or the zero point of PV parameter is the first point where the PV parameter and the SV parameter are equal after a step change in the SV parameter in the trend chart; the trough of MV parameter is the trough point of each fluctuation of the MV parameter curve in the trend chart.

[0094] In one specific embodiment, the operating data of a certain flow control loop is preprocessed to obtain the PV, SV, and MV parameters over a period of time. Then, based on the time sequence, trend graphs of the PV, SV, and MV parameters are constructed. When the SV parameter in the flow control loop undergoes a step change, the trend graph of its phase characteristic points is as follows. Figure 2 As shown; when the SV parameter in this flow control loop does not change abruptly, the trend diagram of its phase characteristic points is as follows. Figure 3 As shown. Based on Figure 2 or Figure 3 The trend chart shown allows users to set corresponding phase characteristic points, or automatically determine and display the phase characteristic points of each parameter according to the rules for finding phase characteristic points. This helps users clearly understand the phase characteristic points of each parameter and accumulate experience in PID parameter tuning. The specific process of automatically finding the phase characteristic points of each parameter is as follows:

[0095] (1) Filter the curves of each parameter in the constructed trend chart to remove useless noise.

[0096] (2) Fit the trend data using a fitting algorithm to fit the curve of the trend graph into a smooth curve.

[0097] (3) Identify whether the SV parameter in the control loop has undergone a step change. If a step change in the SV parameter is detected, the location where the step change occurs is determined as the starting point of the SV parameter change. If no step change in the SV parameter is detected, the control program executes the next step.

[0098] (4) Determine the first point where the PV parameter curve and the SV parameter curve are equal after the SV parameter undergoes a step change as the PV parameter zero point; or, determine the first point where the PV parameter curve and the SV parameter curve are equal when the SV parameter does not undergo a step change as the PV parameter zero point.

[0099] (5) In the PV parameter curve after the zero point of the PV parameter, the point where the SV parameter is equal to the PV parameter is used as the dividing point to divide the PV parameter curve into several segments. The point with the maximum difference between the PV parameter curve and the SV parameter in each segment is used as the peak or trough. The PV parameter value at the peak is greater than the SV parameter value, and the PV parameter value at the trough is less than the SV parameter value.

[0100] (6) In the MV parameter curve, set a reference value line that runs through each fluctuation curve of the MV parameter. The reference value line is a straight line with the same value. Then, take the point where the MV parameter and the reference value line are equal as the dividing point to divide the MV parameter curve into several segments. The point with the largest difference between the MV parameter curve and the reference value line in each segment is taken as the peak or trough. The MV parameter value at the peak is greater than the value of the reference value line, and the MV parameter value at the trough is less than the value of the reference value line.

[0101] S3. When the SV parameter has a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters to obtain the PID parameters.

[0102] For example, refer to Figure 4 As shown, step S3 in this embodiment may include the following sub-steps S31 to S34:

[0103] S31. When the SV parameter has a step change, obtain the overshoot and rise time based on the phase characteristic points of the PV parameter and the SV parameter.

[0104] The formula for obtaining the overshoot is:

[0105] Overshoot = |PV max -SV new | / ΔSV*100% (1)

[0106] In equation (1), Overshoot represents the overshoot, PV max SV represents the peak value of the first PV parameter after a step change in the SV parameter. new ΔSV represents the parameter value after a step change in the SV parameter, and ΔSV represents the magnitude of the step change in the SV parameter.

[0107] The formula for obtaining the rise time is:

[0108] RiseTime = |T1 - T2| (2)

[0109] In equation (2), RiseTime represents the rise time, T1 represents the first moment when the PV parameter reaches its peak after the SV parameter undergoes a step change, and T2 represents the starting moment when the SV parameter undergoes a step change.

[0110] S32. Determine whether the rise time meets the set first threshold range.

[0111] S33a. If the rise time is greater than 0.9 times the target rise time and less than 1.1 times the target rise time, then maintain the proportionality in the initial PID parameters.

[0112] S33b If the rise time is less than 0.9 times the target rise time or greater than 1.1 times the target rise time, the proportional gain in the PID initial parameters is adjusted according to the rise time, and it is determined whether the overshoot meets the set second threshold range.

[0113] In this embodiment, since the proportional gain and proportional coefficient exhibit a negative correlation in the PID control system, and the proportional coefficient and the rise time of the system's step response also exhibit a negative correlation, increasing the proportional coefficient can usually effectively shorten the rise time. Due to the direct amplification effect of proportional control on the system's instantaneous deviation: an increased proportional coefficient generates a stronger control output, thereby accelerating the dynamic response process of the measured value (PV) approaching the setpoint (SV). Conversely, decreasing the proportional coefficient leads to system lag and a correspondingly longer rise time. Therefore, this embodiment employs interval monitoring of the rise time and adaptively adjusts the proportional gain based on rise times exceeding the range, thereby obtaining a suitable proportional coefficient to achieve optimal proportional control. The adjustment formula for adjusting the proportional gain in the initial PID parameters based on the rise time is as follows:

[0114]

[0115] In equation (3), PB′ represents the adjusted proportional gain, Ks represents the iteration coefficient, Tss represents the steady-state time, which is equal to the time interval between two adjacent peaks in the PV parameters, and PB represents the proportional gain in the initial parameters of the PID.

[0116] S34a. If the overshoot is greater than 0.8 and less than 1.1, then maintain the integral time in the initial PID parameters.

[0117] S34b. If the overshoot is greater than 1.1 and the rise time is less than 0.9 times the target rise time, or if the overshoot is in the range of 0 to 0.8 and the rise time is greater than 1.1 times the target rise time, then the integral time in the PID initial parameters shall be adjusted according to the overshoot.

[0118] To further explain, when the overshoot is greater than 1.1 and the rise time is less than 0.9 times the target rise time, the integral time in the PID initial parameters is adjusted by adjusting the overshoot to reduce the integral action. When the overshoot is in the range of 0 to 0.8 and the rise time is greater than 1.1 times the target rise time, the integral time in the PID initial parameters is adjusted by adjusting the overshoot to increase the integral action.

[0119] The adjustment formula for adjusting the integral time in the PID initial parameters based on the overshoot is as follows:

[0120]

[0121] In equation (4), Ti′ represents the adjusted integral time, and Ti represents the integral time in the initial parameters of the PID.

[0122] S4. When there is no step change in the SV parameter, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral judgment index and proportional judgment index obtained from the phase characteristic points of the PV and MV parameters to obtain the PID parameters.

[0123] For example, refer to Figure 5 As shown, step S4 in this embodiment may include the following sub-steps S41 to S44:

[0124] S41. When there is no step change in the SV parameter, obtain the integral judgment index and the proportional judgment index based on the phase characteristic points of the PV parameter and the MV parameter.

[0125] The formula for obtaining the integral judgment index is:

[0126]

[0127] In equation (5), Ki represents the integral judgment index, T1′ represents the first moment when the PV parameter reaches its peak within the set time period, T2′ represents the first moment when the PV parameter curve and the SV parameter curve are equal within the set time period, and T3′ represents the first moment when the MV parameter reaches its trough within the set time period. Figure 3 In the diagram, the starting point of the selected time period is "zero point".

[0128] The formula for obtaining the ratio judgment index is:

[0129] Kp=|T2′-T1′| (6)

[0130] In equation (6), Kp represents the integral judgment index.

[0131] S42. Determine whether the integral judgment index meets the set third threshold range.

[0132] S43a. If the integral judgment index is less than 0.4 and the integral judgment index is greater than 0.1, then the integral time in the initial parameters of the PID is maintained.

[0133] S43b. If the integral judgment index is greater than 0.4 or less than 0.1, the integral time in the PID initial parameters is adjusted according to the integral judgment index, and it is determined whether the proportional judgment index meets the set fourth threshold range.

[0134] To further explain, when the integral criterion is greater than 0.4, the integral time in the PID initial parameters is adjusted using the integral criterion to reduce the integral action. When the integral criterion is less than 0.1, the integral time in the PID initial parameters is adjusted using the integral criterion to increase the integral action.

[0135] The adjustment formula for adjusting the integral time in the PID initial parameters based on the integral performance index is as follows:

[0136]

[0137] In equation (7), Ti′ represents the adjusted integral time, Ti represents the integral time in the initial parameters of the PID, Tss represents the steady-state time, the steady-state time is equal to the time interval between two adjacent peaks in the PV parameters, and e represents the natural constant.

[0138] S44a. If the proportional judgment index is greater than 0.225 times the steady-state time and less than 0.275 times the steady-state time, then maintain the proportionality in the initial parameters of the PID controller.

[0139] S44b. If the proportional judgment index is less than 0.225 times the steady-state time and the integral judgment index is less than 0.1, or the proportional judgment index is greater than 0.275 times the steady-state time and the integral judgment index is greater than 0.4, then the proportionality in the initial parameters of the PID shall be adjusted according to the proportional judgment index.

[0140] To further explain, when the proportional gain is less than 0.225 times the steady-state time and the integral gain is less than 0.1, the proportional gain in the initial PID parameters is adjusted using the proportional gain to reduce the proportional effect. When the proportional gain is greater than 0.275 times the steady-state time and the integral gain is greater than 0.4, the proportional gain in the initial PID parameters is adjusted using the proportional gain to increase the proportional effect.

[0141] The adjustment formula for adjusting the proportional gain in the initial parameters of a PID controller based on the proportionality index is as follows:

[0142]

[0143] In equation (8), PB′ represents the adjusted proportional gain, and PB represents the proportional gain in the initial parameters of the PID controller.

[0144] Furthermore, the PID parameter tuning method based on phase analysis proposed in this embodiment also includes: S5, writing the PID parameters into the control loop and verifying the tuning results of the PID parameters. Step S5 is as follows:

[0145] S51. Write the PID parameters into the control loop and determine whether the deviation between the PV parameters and SV parameters of the control loop is greater than the set deviation threshold.

[0146] S52a. If the deviation between the PV parameter and the SV parameter of the control loop is greater than the set deviation threshold, then it is determined that the PID parameter needs to be tuned again.

[0147] S52b. If the deviation between the PV parameter and the SV parameter of the control loop is not greater than the set deviation threshold, then the PID parameter tuning is considered complete.

[0148] In this embodiment, after the adjusted PID parameters are written into the control loop, when the control loop is in automatic mode, the deviation between the PV parameters and the SV parameters is obtained using the following formula (9). When the deviation value is less than the set deviation threshold, the fluctuation range of the PV parameters is small, and it is determined that the PID parameters have been tuned. When the deviation value is greater than the set deviation threshold, the fluctuation range of the PV parameters is large, and it is determined that the PID parameters need to be tuned a second time. The deviation threshold is 1% of the range value of the PV parameters.

[0149]

[0150] In equation (9), △MVn represents the change value of the MV parameter, En represents the deviation value between the PV parameter and the SV parameter, △En represents the change value of the deviation value, PB represents the proportionality, Ti represents the integral time, and △Un represents the differential term.

[0151] also, Figure 6 A schematic diagram of a PID parameter tuning system based on phase analysis provided by the present invention is shown below. Figure 6 As shown, the present invention also provides a PID parameter tuning system 300 based on phase analysis, which includes:

[0152] The preprocessing module 301 is used to preprocess the operating data of the control loop to obtain historical trend values ​​and PID initial parameters within a set time period. The historical trend values ​​include PV parameters, SV parameters and MV parameters.

[0153] The phase analysis module 302 is used to construct a trend graph of historical trend values ​​according to the time sequence, and to perform phase analysis processing on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter.

[0154] The first PID parameter adjustment module 303 is used to adjust the proportional gain and integral time in the initial PID parameters based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters when there is a step change in the SV parameter, so as to obtain the PID parameters.

[0155] The second PID parameter adjustment module 304 is used to adjust the proportional gain and integral time in the initial PID parameters based on the integral judgment index and proportional judgment index obtained from the phase characteristic points of the PV and MV parameters when there is no step change in the SV parameter, so as to obtain the PID parameters.

[0156] The functions of each module in this system are described in the relevant descriptions in the above method embodiments, and will not be repeated here.

[0157] On the other hand, the present invention also provides an electronic device, including a processor and a memory, wherein the memory stores steps for controlling the aforementioned PID parameter tuning method based on phase analysis.

[0158] The following is for reference. Figure 7 It shows a schematic diagram of the structure of a computer system 400 suitable for implementing electronic devices according to embodiments of the present application. Figure 7 The electronic device shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of this application.

[0159] like Figure 7As shown, the computer system 400 includes a central processing unit (CPU) 401, which can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) 402 or programs loaded from storage section 408 into random access memory (RAM) 403. The RAM 403 also stores various programs and data required for the operation of the computer system 400. The CPU 401, ROM 402, and RAM 403 are interconnected via a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0160] The following components are connected to I / O interface 405: an input section 406 including a keyboard, mouse, etc.; an output section 407 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; a storage section 408 including a hard disk, etc.; and a communication section 409 including a network interface card such as a LAN card, modem, etc. The communication section 409 performs communication processing via a network such as the Internet. A drive 410 is also connected to I / O interface 405 as needed. A removable medium 411, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on drive 410 as needed so that computer programs read from it can be installed into storage section 408 as needed.

[0161] In particular, according to embodiments of the present invention, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via communication section 409, and / or installed from removable medium 411. When the computer program is executed by central processing unit (CPU) 401, it performs the functions defined above in the system of this application.

[0162] It should be noted that the computer-readable medium shown in this application can be a computer-readable signal medium, a computer-readable medium, or any combination of the two. A computer-readable medium can be, for example,—but not limited to—an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of a computer-readable medium may include, but are not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this application, a computer-readable medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than a computer-readable medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wire, optical fiber, RF, etc., or any suitable combination thereof.

[0163] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0164] The units described in the embodiments of this application can be implemented in software or hardware. The described units can also be located in a processor, and the names of these units do not necessarily limit the unit itself.

[0165] On the other hand, the present invention also provides a computer-readable medium, which may be included in the device described in the above embodiments; or it may exist alone and not assembled into the device. The computer-readable medium carries one or more programs, which, when executed by the device, cause the device to include the following method steps:

[0166] S1. Preprocess the operating data of the control loop to obtain the historical trend value and PID initial parameters within a set time period. The historical trend value includes PV parameters, SV parameters and MV parameters.

[0167] S2. Construct a trend chart of historical trend values ​​according to the time sequence, and perform phase analysis on each parameter of the historical trend values ​​in the trend chart to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter.

[0168] S3. When the SV parameter has a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters to obtain the PID parameters.

[0169] S4. When there is no step change in the SV parameter, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral judgment index and proportional judgment index obtained from the phase characteristic points of the PV and MV parameters to obtain the PID parameters.

[0170] S5. Write the PID parameters into the control loop and verify the tuning results of the PID parameters.

[0171] In summary, the present invention provides a PID parameter tuning method, system, device, and medium based on phase analysis. The method simulates experienced engineers analyzing control loop characteristics for tuning, assesses the current control loop characteristics, and then uses phase characteristic points such as peaks, troughs, and zeros of the control loop parameter curves to analyze the overshoot and rise time of the PID control system's step response. Based on the overshoot and rise time, an adjustment strategy for the PID parameters is obtained. In this invention, users can obtain reasonable PID parameters after several short adjustment processes, accelerating the PID parameter tuning speed. This PID parameter tuning process is also suitable for control loops with insufficient data sources, and because it simulates experienced engineers analyzing control loop characteristics for tuning, it is more suitable for PID parameter tuning in process industries.

[0172] Since the systems / devices described in the above embodiments of the present invention are systems / devices used to implement the methods of the above embodiments of the present invention, those skilled in the art can understand the specific structure and modifications of the systems / devices based on the methods described in the above embodiments of the present invention, and therefore will not be repeated here. All systems / devices used in the methods of the above embodiments of the present invention fall within the scope of protection of the present invention.

[0173] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0174] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, as well as combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions.

[0175] It should be noted that in the description of this invention, the word "a" or "an" preceding a component does not exclude the existence of multiple such components. This invention can be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. The use of terms such as first, second, third, etc., is merely for convenience and does not indicate any order. These terms can be understood as part of the component names.

[0176] Furthermore, it should be noted that in the description of this specification, the terms "one embodiment," "some embodiments," "embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0177] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning of the basic inventive concept, can make other changes and modifications to these embodiments.

[0178] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from the spirit and scope of the invention.

Claims

1. A PID parameter tuning method based on phase analysis, characterized in that, include: The operating data of the control loop is preprocessed to obtain the historical trend value and PID initial parameters within a set time period. The historical trend value includes PV parameters, SV parameters and MV parameters. A trend graph of the historical trend values ​​is constructed according to the time sequence, and phase analysis is performed on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter. When the SV parameter has a step change, the proportional gain and integral time in the PID initial parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters to obtain the PID parameters. When the SV parameter does not have a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral and proportional gain obtained from the phase characteristic points of the PV and MV parameters to obtain the PID parameters.

2. The method as described in claim 1, characterized in that, The phase feature points include: The starting point of the SV parameter change is the point where the SV parameter undergoes a step change in the trend graph. PV parameter peaks are the peak points of each fluctuation in the PV parameter curve in the trend chart. The PV parameter zero point is the first point in the trend chart where the PV parameter curve and the SV parameter curve are equal in value when the SV parameter does not change abruptly, or the PV parameter zero point is the first point in the trend chart where the PV parameter and the SV parameter are equal after the SV parameter undergoes abrupt change. MV parameter troughs are the trough points of each fluctuation in the MV parameter curve in the trend chart.

3. The method as described in claim 1, characterized in that, When the SV parameter exhibits a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters, resulting in the following PID parameters: When the SV parameter has a step change, the overshoot and rise time are obtained based on the phase characteristic points of the PV and SV parameters. Determine whether the rise time meets the set first threshold range; If the rise time is greater than 0.9 times the target rise time and less than 1.1 times the target rise time, then maintain the proportionality in the initial PID parameters. If the rise time is less than 0.9 times the target rise time or greater than 1.1 times the target rise time, the proportional gain in the PID initial parameters is adjusted according to the rise time, and it is determined whether the overshoot meets the set second threshold range. If the overshoot is greater than 0.8 and less than 1.1, then the integral time in the PID initial parameters is maintained. If the overshoot is greater than 1.1 and the rise time is less than 0.9 times the target rise time, or if the overshoot is in the range of 0 to 0.8 and the rise time is greater than 1.1 times the target rise time, then the integral time in the PID initial parameters will be adjusted according to the overshoot.

4. The method as described in claim 3, characterized in that, The formula for obtaining the overshoot is: Overshoot=|PV max -SV new | / △SV*100% (1) In equation (1), Overshoot represents the overshoot, PV max SV represents the peak value of the first PV parameter after a step change in the SV parameter. new ΔSV represents the parameter value after a step change in the SV parameter, and ΔSV represents the magnitude of the step change in the SV parameter. The formula for obtaining the rise time is: RiseTime = |T1 - T2| (2) In equation (2), RiseTime represents the rise time, T1 represents the first moment when the PV parameter reaches its peak after the SV parameter undergoes a step change, and T2 represents the starting moment when the SV parameter undergoes a step change. The adjustment formula for adjusting the proportional gain in the PID initial parameters based on the rise time is as follows: In equation (3), PB′ represents the adjusted proportional gain, Ks represents the iteration coefficient, Tss represents the steady-state time, which is equal to the time interval between two adjacent peaks in the PV parameters, and PB represents the proportional gain in the initial parameters of the PID. The adjustment formula for adjusting the integral time in the PID initial parameters based on the overshoot is as follows: In equation (4), Ti′ represents the adjusted integral time, and Ti represents the integral time in the initial parameters of the PID.

5. The method as described in claim 1, characterized in that, When the SV parameter does not exhibit a step change, the proportional gain and integral time in the initial PID parameters are adjusted based on the integral and proportional gain indicators obtained from the phase characteristic points of the PV and MV parameters, resulting in the following PID parameters: When the SV parameter does not have a step change, the integral judgment index and the proportional judgment index are obtained based on the phase characteristic points of the PV parameter and the MV parameter. Determine whether the integral judgment index meets the set third threshold range; If the integral judgment index is less than 0.4 and greater than 0.1, then the integral time in the PID initial parameters is maintained. If the integral judgment index is greater than 0.4 or less than 0.1, the integral time in the PID initial parameters will be adjusted according to the integral judgment index, and it will be determined whether the proportional judgment index meets the set fourth threshold range. If the proportional judgment index is greater than 0.225 times the steady-state time and less than 0.275 times the steady-state time, then the proportionality in the initial PID parameters is maintained. If the proportional judgment index is less than 0.225 times the steady-state time and the integral judgment index is less than 0.1, or if the proportional judgment index is greater than 0.275 times the steady-state time and the integral judgment index is greater than 0.4, then the proportionality in the initial parameters of the PID controller will be adjusted according to the proportional judgment index.

6. The method as described in claim 5, characterized in that, The formula for obtaining the integral judgment index is as follows: In equation (5), Ki represents the integral judgment index, T1′ represents the first moment when the PV parameter reaches its peak within the set time period, T2′ represents the first moment when the PV parameter curve and the SV parameter curve are equal within the set time period, and T3′ represents the first moment when the MV parameter reaches its trough within the set time period. The formula for obtaining the ratio judgment index is: Kp=|T2'-T1'| (6) In equation (6), Kp represents the integral judgment index; The adjustment formula for adjusting the integral time in the initial parameters of the PID based on the integral judgment index is as follows: In equation (7), Ti′ represents the adjusted integral time, Ti represents the integral time in the initial parameters of the PID, Tss represents the steady-state time, the steady-state time is equal to the time interval between two adjacent peaks in the PV parameters, and e represents the natural constant. The adjustment formula for adjusting the proportional gain in the initial parameters of the PID based on the proportionality judgment index is as follows: In equation (8), PB′ represents the adjusted proportional gain, and PB represents the proportional gain in the initial parameters of the PID controller.

7. The method as described in claim 1, characterized in that, Also includes: The PID parameters are written into the control loop, and it is determined whether the deviation between the PV parameters and SV parameters of the control loop is greater than the set deviation threshold. If the deviation between the PV parameter and the SV parameter of the control loop is greater than the set deviation threshold, then it is determined that the PID parameter needs to be tuned a second time. If the deviation between the PV parameter and the SV parameter of the control loop is not greater than the set deviation threshold, then the PID parameter tuning is considered complete.

8. A PID parameter tuning system based on phase analysis, characterized in that, include: The preprocessing module is used to preprocess the operating data of the control loop to obtain historical trend values ​​and PID initial parameters within a set time period. The historical trend values ​​include PV parameters, SV parameters and MV parameters. The phase analysis module is used to construct a trend graph of the historical trend values ​​according to the time sequence, and to perform phase analysis processing on each parameter of the historical trend values ​​in the trend graph to obtain the phase feature points and step change information of the SV parameter corresponding to each parameter. The first PID parameter tuning module is used to adjust the proportional gain and integral time in the initial PID parameters based on the overshoot and rise time obtained from the phase characteristic points of the PV and SV parameters when there is a step change in the SV parameter, so as to obtain the PID parameters. The second PID parameter tuning module is used to adjust the proportional gain and integral time in the initial PID parameters based on the integral judgment index and proportional judgment index obtained from the phase characteristic points of the PV and MV parameters when there is no step change in the SV parameter, so as to obtain the PID parameters.

9. An electronic device, characterized in that, include: processor; The memory stores the steps of the PID parameter tuning method based on phase analysis as described in any one of claims 1-7 for controlling the processor.

10. A computer-readable medium having computer-executable instructions stored thereon, characterized in that, When the executable instructions are executed by the processor, they implement the steps of a PID parameter tuning method based on phase analysis as described in any one of claims 1-7.

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