Hydraulic station based on fuzzy PID control and control method

Abstract

The invention discloses a hydraulic station based on fuzzy PID control and a control method, and relates to the technical field of oil drilling and workover, the hydraulic station comprises an oil tank, an oil pump, a Siemens PLC, a touch screen, a fuzzy controller and a proportional valve group, and further comprises a backflow filtering structure arranged on the oil tank; the backflow filtering structure comprises a backflow pipe, the backflow pipe is installed at the top of the oil tank, one side of the backflow pipe communicates with an oil inlet pipe, the inner wall of the backflow pipe is rotationally connected with a rotating disc, the top of the rotating disc is hinged to a plurality of sets of rotating frames through torsional springs, and the tops of the rotating frames are connected with first connecting frames. The control system has the advantage of high precision of a PID controller and also has the characteristics of high speed and high adaptability of a fuzzy controller, it is guaranteed that an adjusting system has good dynamic and steady state characteristics, good anti-interference performance and high robustness, stable operation of driving equipment is guaranteed, and production efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil well drilling and repairing, in particular to a hydraulic station and a control method based on fuzzy PID control. Background Art

[0002] The hydraulic station is a hydraulic source device consisting of a hydraulic pump, a driving motor, an oil tank, a directional valve, a throttle valve, a relief valve, etc., or a hydraulic device including a control valve. It supplies oil according to the flow direction, pressure and flow required by the driving device. It is suitable for various machines in which the driving device is separated from the hydraulic station. By connecting the hydraulic station and the driving device with an oil pipe, the hydraulic system can achieve various specified actions.

[0003] The hydraulic station is one of the important supporting equipment of the oil drilling and repair machine. During the oil drilling operation, when the hydraulic station storage tank circulates the hydraulic oil, it is necessary to circulate the high-temperature hydraulic oil into the tank again. The hydraulic oil that flows back to the tank again will inevitably carry some impurities. The hydraulic station in the prior art usually uses the filter in the reflux filter to filter the hydraulic oil. When the reflux filter is used for a long time, the impurities on its surface tend to accumulate and become clogged, affecting the reflux of the hydraulic oil. Therefore, the filter needs to be replaced repeatedly, which is time-consuming and laborious. At the same time, when the hydraulic station drives each hydraulic machine to complete the corresponding action, in order to ensure the reliability of the operation of the hydraulic machine, it is necessary to keep the pressure output of each valve of the hydraulic station stable. The controlled object of the hydraulic station control system is a nonlinear and time-varying link. It is difficult to achieve good control effect within the entire speed control range by only using conventional PID control. Summary of the invention

[0004] The purpose of the present invention is to make up for the deficiencies of the prior art and to provide a hydraulic station and a control method based on fuzzy PID control.

[0005] To achieve the above object, the present invention provides the following technical solution: a hydraulic station based on fuzzy PID control, including an oil tank, an oil pump, a Siemens PLC, a touch screen, a fuzzy controller and a proportional valve group, and also includes:

[0006] A reflux filter structure is provided on the oil tank and is used to clean impurities in the refluxed hydraulic oil;

[0007] The reflux filtering structure comprises a reflux pipe, the reflux pipe is installed on the top of the oil tank, one side of the reflux pipe is connected with an oil inlet pipe, the inner wall of the reflux pipe is rotatably connected with a turntable, the top of the turntable is hinged with several groups of rotating frames by a torsion spring, the top of the rotating frame is connected with a first connecting frame, the top of the first connecting frame is bonded with a rubber pad, the top of the reflux pipe is installed with a first hydraulic cylinder, the bottom end of the first hydraulic cylinder is installed with a micro motor, the output shaft of the micro motor is connected with a rotating shaft, the bottom end of the rotating shaft is installed with a second connecting frame, the bottom end of the first connecting frame is connected with a pull rod through a wire rope, an elastic filter screen is connected between two adjacent groups of first connecting frames, second hydraulic cylinders are fixed on both sides of the reflux pipe, the top of the second hydraulic cylinder is connected with a movable shaft through a fixed frame, a groove is provided at the bottom of the inner cavity of the reflux pipe, and the two sides of the reflux pipe are respectively connected with an air inlet pipe and a slag discharge pipe.

[0008] As a preferred solution of the present invention, the bottom end of the pull rod passes through the turntable and is connected to the second connecting frame. When the pull rod moves downward along the inner side of the turntable, the first connecting frame will continue to rotate until the bottom surface is in contact with the top surface of the turntable.

[0009] As a preferred solution of the present invention, the rubber pad is in squeeze contact with the surface of the rotating shaft. When the rubber pad is in contact with the surface of the rotating shaft, the first connecting frame and the elastic filter form a cone. When the bottom surface of the first connecting frame is in contact with the top of the turntable, the first connecting frame and the elastic filter form a column.

[0010] As a preferred solution of the present invention, the outer wall of the baffle is slidably connected to the return pipe, and the outer wall of the baffle is bonded with rubber, and the top of the groove is sealed when the baffle moves downward.

[0011] As a preferred solution of the present invention, the bottom end of the movable shaft passes through the return pipe and is slidably connected to the return pipe, and the air intake pipe is connected to an external air pump.

[0012] As a preferred solution of the present invention, the following steps are included:

[0013] S1. The touch screen sets the pressure value required by each proportional valve corresponding to the equipment and transmits it to the PLC through the network cable;

[0014] S2. After the PLC receives the pressure value set by the touch screen, it converts it into a current value output after calculation;

[0015] S3. The proportional amplifier receives the current signal sent by the PLC, controls the opening of the proportional valve core, and the pressure transmitter feeds back the proportional valve output pressure to the PLC;

[0016] S4.PLC compares the collected proportional valve output pressure with the touch screen set pressure, converts it into a current value through fuzzy control calculation, and adjusts the proportional valve opening.

[0017] As a preferred solution of the present invention, in step S4, on the basis of the conventional PID controller, the pressure deviation and the deviation rate are fuzzy processed, and the control rules in the knowledge base are used to perform online self-tuning on the PID parameters through fuzzy reasoning and clear interface output. Then the PID controller gives a current signal, which is sent to the proportional amplifier to effectively control the proportional valve, so as to achieve the purpose of stabilizing the pressure output;

[0018]

[0019] Among them, K p is the proportional coefficient of the controller, T i is the integration coefficient, T d is the differential coefficient, e(t) is the pressure deviation, and the pressure deviation is the difference between the pressure setting value and the pressure feedback.

[0020] As a preferred solution of the present invention, in step S4, the fuzzy control operation, when the output pressure value is greater than the preset value, adjusts the corresponding parameters within the PID parameter setting range, including increasing K p , reduce T d and adjust T i value.

[0021] As a preferred solution of the present invention, in step S4, the fuzzy control operation, when the output pressure value is within the preset value range, adjusts the corresponding parameters within the PID parameter setting range, including reducing K p , adjust T d and T i , so that T d and T i falls within the preset range.

[0022] As a preferred solution of the present invention, in step S4, when the output pressure value is less than the preset value, the corresponding parameters are adjusted within the PID parameter setting range, including increasing T i and K p , adjust T according to actual conditions d .

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention detects the current actual pressure value and compares it with the desired pressure value according to the pressure value of the equipment driven by the hydraulically driven equipment output as required, and adjusts the opening of the proportional valve through the fuzzy PID controller according to the comparison result, so that the actual pressure value is equal to or close to the desired pressure value, and better handles the uncertainty and nonlinear characteristics of the output pressure of the hydraulic station, so that the output pressure of the hydraulic station remains stable. The present invention has the advantages of high precision of the PID controller and the characteristics of fast speed and strong adaptability of the fuzzy controller, ensuring that the adjustment system has good dynamic and steady-state characteristics, good anti-interference performance and strong robustness, which is conducive to ensuring the stable operation of the driving equipment and improving production efficiency.

[0025] 2. The present invention converts the Siemens PLC into analog output according to the pressure setting value to control the opening of the proportional valve spool. This method uses pressure deviation and deviation rate for fuzzy processing to improve the PID control accuracy. By adjusting the spool opening of the control valve group, the real-time optimization of the hydraulic station output pressure is achieved, and the uncertainty and nonlinear characteristics of the hydraulic station output pressure are better handled, so that the hydraulic station output pressure remains stable.

[0026] 3. The present invention controls the downward movement of the rotating shaft through the operation of the first hydraulic cylinder, so that the wire rope can be driven by pulling the pull rod through the second connecting frame, so that the wire rope drives the first connecting frame to rotate and pull the elastic filter. At this time, the mesh of the elastic filter will expand. At the same time, through the operation of the micro motor, the second connecting frame can be driven to rotate through the rotating shaft, so that the turntable can be driven to rotate along the inner side of the return pipe through the second connecting frame and the pull rod, and the impurities stuck and blocked in the elastic filter are thrown out by centrifugal force. At the same time, through the operation of the second hydraulic cylinder, the movable shaft drives the baffle to push the impurities attached to the inner wall of the return pipe into the inner side of the groove, so that the impurities located inside the groove can be discharged from the slag discharge pipe by inputting air flow into the air intake pipe, thereby facilitating the automatic cleaning of impurities on the surface of the elastic filter.

[0027] Other advantages, objectives and features of the present invention will be set forth in part in the following description and, in part, will be apparent to those skilled in the art based on an examination of the following or may be taught from the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0029] Figure 2 It is a schematic structural diagram of a partial cross-section of the side surface of the present invention;

[0030] Figure 3 For the present invention Figure 2 A schematic diagram of a local enlarged structure;

[0031] Figure 4 is a schematic cross-sectional structural diagram of the first connecting frame of the present invention;

[0032] Figure 5 It is a schematic diagram of the disassembly structure of the first connecting frame and the elastic filter screen of the present invention;

[0033] Figure 6 It is a schematic diagram of the unfolded structure of the first connecting frame and the elastic filter screen of the present invention;

[0034] Figure 7 This is a schematic diagram of a hydraulic station control circuit based on fuzzy PID control according to the present invention;

[0035] Figure 8 It is a schematic diagram of the control principle structure of the hydraulic station based on fuzzy PID control of the present invention.

[0036] In the figure: 1. oil tank; 2. oil pump; 3. return pipe; 4. oil inlet pipe; 5. turntable; 6. rotating frame; 7. first connecting frame; 8. rubber pad; 9. first hydraulic cylinder; 10. micro motor; 11. rotating shaft; 12. second connecting frame; 13. wire rope; 14. pull rod; 15. elastic filter; 16. second hydraulic cylinder; 17. fixed frame; 18. movable shaft; 19. baffle; 20. groove; 21. air inlet pipe; 22. slag discharge pipe. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] like Figure 1-8 As shown, the present invention provides a hydraulic station based on fuzzy PID control, including an oil tank 1, an oil pump 2, a Siemens PLC, a touch screen, a fuzzy controller and a proportional valve group, and also includes:

[0039] A reflux filtering structure, which is arranged on the oil tank 1 and is used to clean impurities in the refluxed hydraulic oil;

[0040] The reflux filtering structure includes a reflux pipe 3, which is installed on the top of the oil tank 1. One side of the reflux pipe 3 is connected to an oil inlet pipe 4. The inner wall of the reflux pipe 3 is rotatably connected to a turntable 5. The top of the turntable 5 is hinged with a plurality of rotating frames 6 through a torsion spring. The top of the rotating frame 6 is connected to a first connecting frame 7. A rubber pad 8 is bonded to the top of the first connecting frame 7. A first hydraulic cylinder 9 is installed on the top of the reflux pipe 3. A micro motor 10 is installed at the bottom of the first hydraulic cylinder 9. The output of the micro motor 10 The shaft is connected to a rotating shaft 11, a second connecting frame 12 is installed at the bottom end of the rotating shaft 11, the bottom end of the first connecting frame 7 is connected to a pull rod 14 through a wire rope 13, an elastic filter screen 15 is connected between two adjacent groups of first connecting frames 7, second hydraulic cylinders 16 are fixed on both sides of the return pipe 3, the top of the second hydraulic cylinder 16 is connected to a movable shaft 18 through a fixed frame 17, a groove 20 is provided at the bottom of the inner cavity of the return pipe 3, and the two sides of the return pipe 3 are respectively connected to an air intake pipe 21 and a slag discharge pipe 22.

[0041] Through the cooperation between the rubber pad 8 and the rotating shaft 11, when the rubber pad 8 and the rotating shaft 11 are fitted, the elastic filter 15 will present a cone shape, so the hydraulic oil returning to the inside of the return pipe 3 will be filtered through the elastic filter 15. At this time, some impurities will adhere to the outer surface of the elastic filter 15. When the elastic filter 15 needs to be dredged, the second hydraulic cylinder 16 can be started when the equipment is shut down to drive the movable shaft 18 and the baffle 19 to move to the top through the fixed frame 17, and then the first hydraulic cylinder 9 is started to control the rotating shaft 11 to move downward, so that the pull rod 14 can be pulled through the second connecting frame 12 to drive the wire rope 13, so that it can drive the first connecting frame 7 to rotate to a vertical state, and when the first connecting frame 7 rotates, it will pull the elastic filter 15, and the mesh of the elastic filter 15 will expand, and at the same time, the micro motor 10 The operation of the second connecting frame 12 can drive the second connecting frame 12 to rotate through the rotating shaft 11, so that the turntable 5 can be driven to rotate along the inner side of the return pipe 3 through the second connecting frame 12 and the pull rod 14. Due to the viscosity of the hydraulic oil, impurities will stick to the surface of the elastic filter screen 15. The centrifugal force generated when the elastic filter screen 15 rotates can throw out the impurities stuck and blocked in the elastic filter screen 15. At this time, the impurities will adhere to the inner wall of the return pipe 3 or fall into the inner side of the groove 20. Therefore, the second hydraulic cylinder 16 can be operated to drive the baffle 19 with the movable shaft 18 to push the impurities attached to the inner wall of the return pipe 3 into the inner side of the groove 20 and close the groove 20. Therefore, the impurities located inside the groove 20 can be discharged from the slag discharge pipe 22 by inputting air flow into the air inlet pipe 21, so as to facilitate the automatic cleaning of impurities on the surface of the elastic filter screen 15.

[0042] like Figure 3 , 4As shown, the bottom end of the pull rod 14 passes through the turntable 5 and is connected to the second connecting frame 12. When the pull rod 14 moves downward along the inner side of the turntable 5, the first connecting frame 7 will continue to rotate until the bottom surface is in contact with the top surface of the turntable 5.

[0043] Through the design of the pull rod 14, when the pull rod 14 moves, the first connecting frame 7 can be pulled by the wire rope 13, so that it drives the rotating frame 6 to rotate along the inner side of the turntable 5. At the same time, since the pull rod 14 is located on the inner side of the turntable 5, when the second connecting frame 12 drives the pull rod 14 to rotate, it can drive the turntable 5 to rotate synchronously along the inner side of the reflux pipe 3.

[0044] like Figure 5 , 6 As shown, the rubber pad 8 is in squeeze contact with the surface of the rotating shaft 11. When the rubber pad 8 is in contact with the surface of the rotating shaft 11, the first connecting frame 7 and the elastic filter 15 form a cone. When the bottom surface of the first connecting frame 7 is in contact with the top of the turntable 5, the first connecting frame 7 and the elastic filter 15 form a column.

[0045] The rubber pad 8 cooperates with the rotating shaft 11, and since the first connecting frame 7 is made of elastic material, the rotating shaft 11 can be covered, so as to avoid a gap between the first connecting frame 7 and the elastic filter 15 and the rotating shaft 11, so that the hydraulic oil flows along the surface of the elastic filter 15 and is filtered out.

[0046] like Figure 3 As shown, the outer wall of the baffle 19 is slidably connected to the return pipe 3, and the outer wall of the baffle 19 is bonded with rubber, and the top of the groove 20 is sealed when the baffle 19 moves downward.

[0047] Through the cooperation between the baffle 19 and the reflux pipe 3, when the baffle 19 slides up and down, the impurities on the inner wall of the reflux pipe 3 will be scraped off. At the same time, through the cooperation between the baffle 19 and the groove 20, the groove 20 can be sealed. Therefore, when gas is input into the intake pipe 21, the gas can be prevented from entering the interior of the reflux pipe 3, thereby facilitating the cleaning of impurities inside the groove 20.

[0048] like Figure 3 As shown, the bottom end of the movable shaft 18 passes through the return pipe 3 and is slidably connected to the return pipe 3, and the air intake pipe 21 is connected to an external air pump.

[0049] Through the design of the air inlet pipe 21, an air pump can be connected, so that air flow can be input into the interior of the groove 20. At this time, the air flow will flow along the inner side of the groove 20 and finally be discharged from the slag discharge pipe 22, thereby facilitating the cleaning of impurities inside the turntable 5.

[0050] like Figure 7-8 As shown, the following steps are included:

[0051] S1. The touch screen sets the pressure value required by each proportional valve corresponding to the equipment and transmits it to the PLC through the network cable;

[0052] S2. After the PLC receives the pressure value set by the touch screen, it converts it into a current value output after calculation;

[0053] S3. The proportional amplifier receives the current signal sent by the PLC, controls the opening of the proportional valve core, and the pressure transmitter feeds back the proportional valve output pressure to the PLC;

[0054] S4.PLC compares the collected proportional valve output pressure with the touch screen set pressure, converts it into a current value through fuzzy control calculation, and adjusts the proportional valve opening.

[0055] By setting the pressure value required by each proportional valve corresponding to the equipment on the touch screen, after the PLC receives the pressure setting value, it is converted into current output through the fuzzy controller and PID operation, and the opening of the proportional valve is controlled to achieve the purpose of adjusting the pressure output. This application aims at the control characteristics of the opening of the proportional valve of the hydraulic station, reduces the impact of pressure fluctuations on the controlled equipment, introduces a fuzzy control algorithm to adjust the PID parameters, and achieves the purpose of optimizing the configuration of the PID control system parameters. The device is equipped with a pressure transmitter at the output end of the proportional valve. By collecting the pressure value at the output end of the proportional valve, the measured data is transmitted to the PLC, and the deviation between the pressure setting value and the actual output value is fuzzy processed, thereby further improving the accuracy of fuzzy PID control.

[0056] like Figure 7-8 As shown, in step S4, on the basis of the conventional PID controller, the pressure deviation and the deviation rate are fuzzy processed, and the control rules in the knowledge base are used to perform online self-tuning on the PID parameters through fuzzy reasoning and clear interface output. Then the PID controller gives a current signal, which is sent to the proportional amplifier to effectively control the proportional valve, so as to achieve the purpose of stabilizing the pressure output;

[0057]

[0058] Among them, K p is the proportional coefficient of the controller, T i is the integration coefficient, T d is the differential coefficient, e(t) is the pressure deviation, and the pressure deviation is the difference between the pressure setting value and the pressure feedback.

[0059] The pressure setting value of Siemens PLC is converted into analog output to control the opening of the proportional valve core. This method uses fuzzy processing of pressure deviation and deviation rate to improve the PID control accuracy. By adjusting the valve core opening of the control valve group, the real-time optimization of the hydraulic station output pressure is achieved, and the uncertainty and nonlinear characteristics of the hydraulic station output pressure are better handled, so that the hydraulic station output pressure remains stable.

[0060] like Figure 7-8 As shown, in step S4, the fuzzy control operation, when the output pressure value is greater than the preset value, adjusts the corresponding parameters within the PID parameter setting range, including increasing K p , reduce T d and adjust T i value.

[0061] like Figure 7-8 As shown, in step S4, the fuzzy control operation, when the output pressure value is within the preset value range, adjusts the corresponding parameters within the PID parameter setting range, including reducing K p , adjust T d and T i , so that T d and T i falls within the preset range.

[0062] like Figure 7-8 As shown, in step S4, when the output pressure value is less than the preset value, the corresponding parameters are adjusted within the PID parameter setting range, including increasing T i and K p , adjust T according to actual conditions d .

[0063] Working principle:

[0064] First, the touch screen is used to set the pressure value required by each proportional valve corresponding to the device, and it is transmitted to the PLC through the network cable. After the PLC receives the pressure value set by the touch screen, it is converted into a current value output after calculation. Then the proportional amplifier receives the current signal sent by the PLC to control the opening of the proportional valve spool. The pressure transmitter feeds back the proportional valve output pressure to the PLC. Finally, the PLC compares the collected proportional valve output pressure with the touch screen set pressure, converts it into a current value through fuzzy control operation, and adjusts the proportional valve opening, thereby achieving the purpose of optimizing the configuration of the PID control system parameters. The device is equipped with a pressure transmitter at the output end of the proportional valve. By collecting the pressure value at the output end of the proportional valve, the measured data is transmitted to the PLC, and the deviation between the pressure setting value and the actual output value is fuzzy processed, thereby further improving the accuracy of fuzzy PID control.

[0065] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hydraulic station based on fuzzy PID control, comprising an oil tank (1), an oil pump (2), a Siemens PLC, a touch screen, a fuzzy controller and a proportional valve group, characterized in that: Also includes: A reflux filtering structure, which is arranged on the oil tank (1) and is used to clean impurities in the refluxed hydraulic oil; The reflux filtering structure comprises a reflux pipe (3), the reflux pipe (3) is installed at the top of the oil tank (1), one side of the reflux pipe (3) is connected to an oil inlet pipe (4), the inner wall of the reflux pipe (3) is rotatably connected to a turntable (5), the top of the turntable (5) is hinged with a plurality of rotating frames (6) through a torsion spring, the top of the rotating frame (6) is connected to a first connecting frame (7), the top of the first connecting frame (7) is bonded with a rubber pad (8), the top of the reflux pipe (3) is installed with a first hydraulic cylinder (9), the bottom of the first hydraulic cylinder (9) is installed with a micro motor (10), the micro motor (10) The output shaft is connected to a rotating shaft (11), a second connecting frame (12) is installed at the bottom end of the rotating shaft (11), the bottom end of the first connecting frame (7) is connected to a pull rod (14) via a steel wire rope (13), an elastic filter screen (15) is connected between two adjacent groups of first connecting frames (7), second hydraulic cylinders (16) are fixed on both sides of the return pipe (3), the top of the second hydraulic cylinder (16) is connected to a movable shaft (18) via a fixed frame (17), a groove (20) is provided at the bottom of the inner cavity of the return pipe (3), and an air intake pipe (21) and a slag discharge pipe (22) are respectively connected to the two sides of the return pipe (3).

2. The hydraulic station based on fuzzy PID control according to claim 1 is characterized in that: The bottom end of the pull rod (14) passes through the turntable (5) and is connected to the second connecting frame (12). When the pull rod (14) moves downward along the inner side of the turntable (5), the first connecting frame (7) will continue to rotate until the bottom surface is in contact with the top surface of the turntable (5).

3. The hydraulic station based on fuzzy PID control according to claim 1 is characterized in that: The rubber pad (8) is in compression contact with the surface of the rotating shaft (11). When the rubber pad (8) is in contact with the surface of the rotating shaft (11), the first connecting frame (7) and the elastic filter screen (15) form a cone. When the bottom surface of the first connecting frame (7) is in contact with the top of the rotating disk (5), the first connecting frame (7) and the elastic filter screen (15) form a column.

4. The hydraulic station based on fuzzy PID control according to claim 1 is characterized in that: The outer wall of the baffle (19) is slidably connected to the return pipe (3), and the outer wall of the baffle (19) is bonded with rubber, and the top of the groove (20) is sealed when the baffle (19) moves downward.

5. The hydraulic station based on fuzzy PID control according to claim 1 is characterized in that: The bottom end of the movable shaft (18) passes through the return pipe (3) and is slidably connected to the return pipe (3), and the air intake pipe (21) is connected to an external air pump.

6. A control method for a hydraulic station based on fuzzy PID control applicable to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The touch screen sets the pressure value required by each proportional valve corresponding to the equipment and transmits it to the PLC through the network cable; S2. After the PLC receives the pressure value set by the touch screen, it converts it into a current value output after calculation; S3. The proportional amplifier receives the current signal sent by the PLC, controls the opening of the proportional valve core, and the pressure transmitter feeds back the proportional valve output pressure to the PLC; S4.PLC compares the collected proportional valve output pressure with the touch screen set pressure, converts it into a current value through fuzzy control calculation, and adjusts the proportional valve opening.

7. The hydraulic station control method based on fuzzy PID control according to claim 6 is characterized in that: In step S4, on the basis of the conventional PID controller, the pressure deviation and the deviation rate are fuzzy processed, and the control rules in the knowledge base are used to perform online self-tuning on the PID parameters through fuzzy reasoning and clear interface output. Then the PID controller gives a current signal, which is sent to the proportional amplifier to effectively control the proportional valve, so as to achieve the purpose of stabilizing the pressure output; Among them, K p is the proportional coefficient of the controller, T i is the integration coefficient, T d is the differential coefficient, e(t) is the pressure deviation, and the pressure deviation is the difference between the pressure setting value and the pressure feedback.

8. The hydraulic station control method based on fuzzy PID control according to claim 7 is characterized in that: In step S4, the fuzzy control operation, when the output pressure value is greater than the preset value, adjusts the corresponding parameters within the PID parameter setting range, including increasing K p , reduce T d and adjust T i value.

9. The hydraulic station control method based on fuzzy PID control according to claim 7 is characterized in that: In step S4, the fuzzy control operation, when the output pressure value is within the preset value range, adjusts the corresponding parameters within the PID parameter setting range, including reducing K p , adjust T d and T i , so that T d and T i falls within the preset range.

10. The hydraulic station control method based on fuzzy PID control according to claim 7, characterized in that: In step S4, when the output pressure value is less than the preset value, the corresponding parameters are adjusted within the PID parameter setting range, including increasing T i and K p , adjust T according to actual conditions d .

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