Segmented throttle valve pressure control method and system based on logistic equation
By adopting a segmented throttle pressure control method based on the logic Stie equation in the automatic pressure control control system of oil drilling, the lack of parameter adjustment and control accuracy of PID controller is solved, and more efficient pressure control is achieved.
Patent Information
- Application Number
- CN202411875656.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-03-28
AI Technical Summary
In the existing automatic oil drilling pressure control control system, the PID controller has problems such as parameter adjustment, oscillation, and overshoot, resulting in low control accuracy.
A segmented throttle valve pressure control method based on the logic Stie equation is adopted. By collecting the target pressure, actual pressure and logic Stie parameters, segmented processing and logic Stie function calculation are performed, and output instructions are generated to control the throttle valve.
It effectively reduces overshoot and overshoot, improves control accuracy, can stabilize pressure faster, and has the advantages of small overshoot and fewer oscillation periods.
Smart Images
Figure CN119717922A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of oil pressure controlled drilling, and in particular to a segmented throttle valve pressure control method and system based on a logistic equation. Background Art
[0002] Automatic control technology has penetrated almost into every application field of the national economy and every aspect of social life, and has been increasingly widely used in many fields such as industrial and agricultural production, transportation, aerospace, and household appliances. In order to achieve various complex control tasks, the controlled object and the control device must first be connected in a certain way to form an organic whole, which is the automatic control system. In the automatic control system, the output of the controlled object, that is, the controlled quantity, is a physical quantity that requires strict control. It can be required to maintain a certain constant value, such as temperature, flow, liquid level, or pressure; and the control device is the overall mechanism that exerts control on the controlled object. It can use different principles and methods to control the controlled object, but the most basic one is the automatic control technology based on closed-loop control.
[0003] like Figure 1 The figure shows a classic closed-loop control system. The system that directly or indirectly feeds back the output to the input end to form a closed loop and realizes automatic control is called a closed-loop control system. It refers to an automatic control system that consists of a signal forward path and a feedback path to form a closed loop, also known as a feedback control system. Traditional closed-loop control systems generally include comparators, controllers, actuators, controlled objects, and feedback links. Generally, PID controllers (proportional-integral-differential controllers) are selected in automatic control of oil drilling pressure control. However, PID controllers have problems such as troublesome parameter adjustment, oscillation, overshoot, etc., and system performance analysis and design are troublesome, and their universality is not high. Summary of the invention
[0004] In view of this, the present application provides a segmented throttle valve pressure control method and system based on the logistic equation to effectively reduce overshoot and excessive overshoot and greatly improve control accuracy.
[0005] To achieve the above objectives, in a first aspect, the present application provides a segmented throttle valve pressure control method based on a logistic equation, comprising:
[0006] Step 1: Collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β;
[0007] Step 2: assigning output command OC, parameter C, parameter β, and initializing target pressure TP;
[0008] Step 3: Calculate the difference DP between the target pressure TP and the actual pressure AP before the throttle valve;
[0009] Step 4: Perform segmented processing on the difference DP, assign values to the logistic parameter C and parameter β according to the difference DP at different segments, and use the logistic function Calculate the intermediate variable N;
[0010] Step 5: According to the different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction OC;
[0011] Step 6: The output command is sent to the actuator after passing through the proportional amplifier. The actuator pushes the valve core of the throttle valve to move forward and backward under the control of the output command to control the pressure before the throttle valve.
[0012] Step 7: Determine whether the difference DP between the actual pressure AP before the current throttle valve and the target pressure TP is less than the set value. If so, end the process; otherwise, return to step 4.
[0013] Furthermore, in step 4, the assignment of logistic parameter C and parameter β according to the difference DP of different stages is specifically as follows:
[0014]
[0015] In the formula, a, b, c and d are all set as constants;
[0016]
[0017] Where m, n, j and k are all set to constants.
[0018] Furthermore, in step 5, according to different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction OC as follows:
[0019] Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function:
[0020]
[0021] Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows:
[0022]
[0023] Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.
[0024] Furthermore, the value of the actual pressure AP is measured by an RS485 bus pressure gauge.
[0025] Furthermore, the model of the proportional amplifier is US-DAS1.
[0026] Furthermore, the set value is 0.5Mpa.
[0027] In a second aspect, the present application provides a segmented throttle valve pressure control system based on a logistic equation, comprising:
[0028] The data acquisition module is used to collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β;
[0029] Initialization module, used for parameter initialization, assigning values to output instruction OC, parameter C and parameter β, and assigning values to target pressure TP;
[0030] A calculation module, used for calculating a difference DP between a target pressure TP before the throttle valve and an actual pressure AP;
[0031] The segment processing module is used to perform segment processing on the difference, assign values to the logistic parameters C and β according to the difference DP at different segments, and Calculate the intermediate variable N;
[0032] The command output module is used to substitute the intermediate variable N into the final output command function of the logic controller PLC according to different pressure characteristics of the control throttle valve to obtain the output command OC;
[0033] An execution module, used for sending the output instruction to the execution mechanism after passing through the proportional amplifier, and the execution mechanism pushes the valve core of the throttle valve to move forward and backward under the control of the output instruction, so as to realize the control of the pressure before the throttle valve;
[0034] The judgment module is used to judge whether the difference DP between the actual pressure AP before the current throttle valve and the target pressure TP is less than the set value. If so, the process is terminated, otherwise the segment processing module is started.
[0035] Furthermore, the segment processing module is specifically used to assign values to the logistic parameter C and the parameter β according to the following formula:
[0036]
[0037] In the formula, a, b, c and d are all set as constants;
[0038]
[0039] Where m, n, j and k are all set to constants.
[0040] Furthermore, the step instruction output module is specifically used to perform the following steps:
[0041] Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function:
[0042]
[0043] Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows:
[0044]
[0045] Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.
[0046] The beneficial effects of this application are:
[0047] Compared with the prior art, the beneficial effects of this application are:
[0048] 1. The segmented throttle valve pressure control method based on the logistic equation of the present application can stabilize the pressure quickly, and has the advantages of small overshoot and fewer oscillation cycles;
[0049] 2. The segmented throttle valve pressure control method based on the logistic equation in this application can be applied to industrial control to effectively prevent excessive control overshoot, which is of great significance for the research in the field of fine control;
[0050] 3. This application can be applied not only to the petrochemical field, but also to other industrial scenarios that require automatic control, and has good universality. BRIEF DESCRIPTION OF THE DRAWINGS
[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0052] Figure 1 It is a classic closed-loop control system;
[0053] Figure 2 This is a flow chart of a segmented throttle valve pressure control method based on the logistic equation of this application;
[0054] Figure 3 It is a standard logistic curve diagram;
[0055] Figure 4 This is a structural block diagram of a segmented throttle valve pressure control system based on the logistic equation of this application;
[0056] Figure 5 This is a CV curve diagram of a 3-inch throttle valve in an embodiment of the present application;
[0057] Figure 6 Graph showing input command VS output current of the proportional amplifier in the embodiment of the present application;
[0058] Figure 7 This is a test effect diagram of the pressure difference of 0-5Mpa in the embodiment of this application. DETAILED DESCRIPTION
[0059] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.
[0060] This application proposes a segmented throttle valve pressure control method and system based on the logistic equation. The use of the logistic equation in the control system can better approximate the target value. For ease of understanding, the logistic equation is Derived, normalized to the molecule:
[0061]
[0062] Substituting Z=α+βt into the equation:
[0063]
[0064] Expand to:
[0065]
[0066] Let C = e -α ,have to
[0067]
[0068] When C=1,β=1,
[0069]
[0070] Formula (5) is the standard logistic distribution. Figure 3 As shown:
[0071] For the function graph Figure 3 It can be found from the observation that when t=0, the derivative is the largest, when t<0, as t increases, its derivative increases, and when t>0, as t increases, its derivative decreases. It can be seen that applying the standard logistic mathematical curve to industrial control can effectively prevent excessive control overshoot, which is of great significance for the study of fine control.
[0072] Based on the above analysis, if Figure 2 As shown, the present application provides a segmented throttle valve pressure control method based on the logistic equation, comprising:
[0073] Step 1: Collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β;
[0074] Step 2: Parameter initialization, assigning values to the output command OC, parameter C and parameter β, and assigning values to the target pressure TP;
[0075] Step 3: Calculate the difference DP between the target pressure TP and the actual pressure AP before the throttle valve;
[0076] Step 4: Process the difference in sections, assign values to the logistic parameters C and β according to the differences in different sections, and use the logistic function Calculate the intermediate variable N;
[0077] Step 5: According to the different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction OC;
[0078] Step 6: The output command is sent to the actuator after passing through the proportional amplifier. The actuator pushes the valve core of the throttle valve to move forward and backward under the control of the output command OC to control the pressure before the throttle valve.
[0079] Step 7: Determine whether the difference DP between the actual pressure AP before the current throttle valve and the target pressure TP is less than the set value. If so, end the process; otherwise, return to step 4.
[0080] Furthermore, in step 4, the assignment of logistic parameter C and parameter β according to the difference DP of different stages is specifically as follows:
[0081]
[0082] Wherein, a, b, c and d are all constants greater than or equal to zero, for example, a=1, b=0.7, c=0.5, d=0.1;
[0083]
[0084] Wherein, m, n, j and k are all constants greater than or equal to zero, for example, m=0.2, n=0.6, j=1.2, k=2.
[0085] Furthermore, in step 5, according to different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction OC as follows:
[0086] Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function:
[0087]
[0088] Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows:
[0089]
[0090] Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.
[0091] Furthermore, the value of the actual pressure AP is measured by an RS485 bus pressure gauge.
[0092] Furthermore, the model of the proportional amplifier is US-DAS1.
[0093] Furthermore, the set value is 0.5Mpa.
[0094] Second, as Figure 4 As shown, the present application provides a segmented throttle valve pressure control system based on the logistic equation, comprising:
[0095] The data acquisition module 410 is used to collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β;
[0096] Initialization module 420, used for parameter initialization, assigning values to output command OC, parameter C and parameter β, and assigning values to target pressure TP;
[0097] A calculation module 430, for calculating the difference between the target pressure TP before the throttle valve and the actual pressure AP;
[0098] The segment processing module 440 is used to perform segment processing on the difference, assign values to the logistic parameter C and parameter β according to the difference of different segments, and Calculate the intermediate variable N;
[0099] The instruction output module 450 is used to substitute the intermediate variable N into the final output instruction function of the logic controller PLC according to different pressure characteristics of the control throttle valve to obtain an output instruction;
[0100] An execution module 460, used for sending the output instruction to the execution mechanism after passing through the proportional amplifier, and the execution mechanism pushes the valve core of the throttle valve to move forward and backward under the control of the output instruction to realize the control of the pressure before the throttle valve;
[0101] The judgment module 470 is used to judge whether the difference between the current actual pressure AP before the throttle valve and the target pressure is less than a set value. If so, the process is terminated; otherwise, the segment processing module 440 is started.
[0102] Furthermore, the segment processing module 440 is specifically used to assign values to the logistic parameter C and the parameter β according to the following formula:
[0103]
[0104] Where a, b, c and d are all constants greater than or equal to zero;
[0105]
[0106] Wherein, m, n, j and k are all constants greater than or equal to zero.
[0107] Furthermore, the step instruction output module 450 is specifically used to perform the following steps:
[0108] Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function:
[0109]
[0110] Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows:
[0111]
[0112] Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.
[0113] Example:
[0114] In order to verify the feasibility and control effect of this application scheme, the following experiments are set up:
[0115] Assume that the difference e between the actual pressure AP before the throttle valve and the target pressure TP is 0-5 MPa, and the set value is 0.5 MPa; the difference is segmented into 0-1 MPa, 1-3 MPa, 3-4 MPa and 4-5 MPa.
[0116] Select a 3-inch throttle valve to control the pressure before the valve. Its CV curve is as follows: Figure 5 As shown, the liquid inlet pipeline is installed with a RS485 bus pressure sensor with an accuracy of ±0.1%. The RS485 bus channel has a good communication effect and a high communication rate, and is suitable for control systems with high real-time requirements. The flow is formed in the pipeline by a horizontal injection pump, the test medium is clean water, and the test flow is 12L / S. The logic controller is the NA200H wide temperature CPU201-1101 of Nanda Aotuo, the analog output module is the 12-bit AOM201, and the US-DAS1 of Zhuoke Electro-hydraulic is used as the proportional amplifier. The input-output relationship is as follows Figure 6 As shown. The logic controller collects RS485 bus pressure data as feedback signal, and the command current is output by the PLC program. The command is transmitted to the electro-hydraulic proportional valve through the amplifier US-DAS1. The electro-hydraulic proportional valve changes the working position of the valve core according to the input current signal, adjusts the opening size of the electro-hydraulic proportional valve, and thus changes the amount of hydraulic oil in the channel, thereby completing the flow output proportional to the input current. The output hydraulic oil drives the hydraulic motor to rotate. Through the judgment of the PLC program, the reversing valve signal is given to change the rotation direction of the hydraulic motor. The hydraulic motor drives the valve core of the throttle valve forward or backward through the piston rod, adjusts the throttle valve opening, and realizes the control of the pressure before the throttle valve.
[0117] The pressure of 0-5Mpa is controlled in a step-by-step manner, and the pressure is increased and decreased step by step. Figure 7 Test results shown.
[0118] Pass the test Figure 7 It can be seen that the segmented pressure control system based on the logistic equation can stabilize the pressure quickly, and has the advantages of small overshoot and few oscillation cycles. At present, the pressure control system has been used to carry out pressure control experiments in many wells, and the experimental results are good.
[0119] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A segmented throttle valve pressure control method based on the logistic equation, characterized in that: include: Step 1: Collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β; Step 2: Parameter initialization, assigning values to the output command OC, parameter C and parameter β, and assigning values to the target pressure TP; Step 3: Calculate the difference between the target pressure TP and the actual pressure AP before the throttle valve; Step 4: Process the difference in sections, assign values to the logistic parameters C and β according to the differences in different sections, and use the logistic function Calculate the intermediate variable N; Step 5: According to the different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction; Step 6: The output command is sent to the actuator after passing through the proportional amplifier. The actuator pushes the valve core of the throttle valve to move forward and backward under the control of the output command to control the pressure before the throttle valve. Step 7: Determine whether the difference between the actual pressure AP before the current throttle valve and the target pressure is less than the set value. If so, end the process; otherwise, return to step 4.
2. The segmented throttle valve pressure control method based on the logistic equation according to claim 1, characterized in that: In step 4, the assignment of logistic parameter C and parameter β according to the difference DP of different segments is specifically as follows: In the formula, a, b, c and d are all set as constants; Where m, n, j and k are all set to constants.
3. The segmented throttle valve pressure control method based on the logistic equation as claimed in claim 2, characterized in that: In step 5, according to the different pressure characteristics of the throttle valve, the intermediate variable N is substituted into the final output instruction function of the logic controller PLC to obtain the output instruction OC as follows: Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function: Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows: Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.
4. The segmented throttle valve pressure control method based on the logistic equation according to any one of claims 1 to 3, characterized in that: The value of the actual pressure AP is measured by a RS485 bus pressure gauge.
5. The segmented throttle valve pressure control method based on the logistic equation according to any one of claims 1 to 3, characterized in that: The model of the proportional amplifier is US-DAS1.
6. The segmented throttle valve pressure control method based on the logistic equation according to any one of claims 1 to 3, characterized in that: The set value is 0.5Mpa.
7. A segmented throttle valve pressure control system based on the logistic equation, characterized in that: include: The data acquisition module is used to collect variable data, including target pressure (TP), actual pressure (AP), output commands (OC), logistic parameter C and logistic parameter β; Initialization module, used for parameter initialization, assigning values to output instruction OC, parameter C and parameter β, and assigning values to target pressure TP; A calculation module, used for calculating the difference between the target pressure TP and the actual pressure AP before the throttle valve; The segment processing module is used to perform segment processing on the difference, assign values to the logistic parameter C and parameter β according to the difference of different segments, and Calculate the intermediate variable N; The instruction output module is used to substitute the intermediate variable N into the final output instruction function of the logic controller PLC according to different pressure characteristics of the control throttle valve to obtain the output instruction; An execution module, used for sending the output instruction to the execution mechanism after passing through the proportional amplifier, and the execution mechanism pushes the valve core of the throttle valve to move forward and backward under the control of the output instruction, so as to realize the control of the pressure before the throttle valve; The judgment module is used to judge whether the difference between the actual pressure AP before the current throttle valve and the target pressure is less than the set value. If so, the process is terminated, otherwise the segment processing module is started.
8. The segmented throttle valve pressure control system based on the logistic equation as claimed in claim 7, characterized in that: The segment processing module is specifically used to assign values to the logistic parameter C and the parameter β according to the following formula: In the formula, a, b, c and d are all set as constants; Where m, n, j and k are all set to constants.
9. The segmented throttle valve pressure control system based on the logistic equation as claimed in claim 8, characterized in that: The step instruction output module is specifically used to perform the following steps: Step 5.1: Determine the base current BC according to the value of the pressure difference DP. The base current BC is determined by the piecewise rounding function: Step 5.2: Continuously adjust the output OC rate SR value according to the target pressure TP and the pressure difference DP. The adjustment formula is as follows: Step 5.3: Obtain the output instruction OC according to the formula OC=BC+N*DP*SR.