High-water-base proportional valve and control system and pulseless control method thereof

Abstract

The invention relates to the technical field of valves, in particular to a high-water-base proportional valve and a control system and a pulseless control method thereof. The high-water-base proportional valve comprises a valve body, a cavity penetrating through the valve body is formed in the valve body, the cavity is divided into a front end part and a rear end part, the front end part of the cavity serves as a liquid return opening, and the rear end part of the cavity is used for arranging a liquid return valve element, a main spring, a main valve element, a liquid return valve sleeve and a main valve sleeve; a liquid return control port, a liquid inlet, a right control port, a working port and a left control port which are communicated with the rear end part of the cavity are formed in the side surface of the valve body; the front section of the main valve element is sleeved with the front end of the main valve sleeve, the liquid return valve sleeve is sleeved with the rear end of the main valve sleeve, and through holes corresponding to the liquid return control port, the liquid inlet, the right control port, the working port and the left control port are formed in the main valve sleeve. According to the scheme, stepless smooth flow adjustment of the hydraulic system is achieved, the attitude control precision of the hydraulic support is improved, and the safety and reliability of the hydraulic system in dangerous occasions such as coal mines are enhanced.

Description

Technical Field

[0001] The present invention relates to the field of valve technology, and in particular to a high water-based proportional valve and a control system and a pulsation-free control method thereof. Background Art

[0002] In coal mines and other high-risk environments, the safety and efficiency of hydraulic systems are crucial. At present, high-water-based proportional valves, as the key to flow control under pure water or emulsion media, play an irreplaceable role in achieving precise control of hydraulic systems and improving explosion-proof performance. However, the limitations of traditional switch valve control, especially the problem of over-extension or over-retraction of hydraulic cylinders, seriously affect the fine posture management of hydraulic supports, thereby threatening operational safety.

[0003] In the existing technology, high-water-based proportional valves are roughly divided into three categories according to the control method: high-speed switching valve pilot type, which is limited by the switching frequency and easily causes valve core displacement fluctuations, damaging system stability; motor pilot type, which faces the difficulty of meeting intrinsic safety standards and implies potential risks; balanced type controlled by a pilot pressure reducing valve, which relies too much on the performance of the pressure reducing valve, increases the difficulty of design and debugging, and hinders popularization and application. Summary of the invention

[0004] The present invention provides a high-water-based proportional valve and a control system and a pulsation-free control method thereof, which are used to solve the defects of the high-water-based proportional valve in the prior art, such as unstable control, large valve core displacement pulsation, difficulty in ensuring intrinsic safety and high complexity of design and debugging, so as to realize stepless and smooth adjustment of the flow of the hydraulic system, improve the control accuracy of the hydraulic support posture, and enhance the safety and reliability of the hydraulic system in dangerous places such as coal mines.

[0005] The present invention provides a high-water-based proportional valve, comprising: a valve body, a cavity penetrating the valve body is provided inside the valve body, the cavity is divided into a front end part and a rear end part, the front end part of the cavity is used as a liquid return port, and the rear end part of the cavity is used to set a liquid return valve core, a main spring, a main valve core, a liquid return valve sleeve and a main valve sleeve; a liquid return control port, a liquid inlet, a right control port, a working port and a left control port connected to the rear end part of the cavity are provided on the side of the valve body; the front end of the main valve sleeve is sleeved on the front section of the main valve core and The rear end of the main valve sleeve is sleeved on the liquid return valve sleeve, and the main valve sleeve is provided with through holes corresponding to the liquid return control port, the liquid inlet, the right control port, the working port and the left control port; the liquid entering from the left control port and the right control port applies rightward and leftward forces to the main valve core respectively through the corresponding through holes provided on the main valve sleeve; the liquid entering from the liquid return control port applies rightward force to the liquid return valve core after passing through the corresponding through holes provided on the main valve sleeve and the through holes on the liquid return valve sleeve.

[0006] According to a high-water-based proportional valve of the present invention, the main valve core includes a coaxial front section, a middle section and a rear section, the front section of the main valve core is a cylindrical hollow structure, and the main spring is arranged inside the cylindrical hollow structure; the radius of the middle section and the rear section of the main valve core is smaller than the radius of the front section of the main valve core, and the middle section of the main valve core is hollow inside; the rear section of the main valve core is sleeved with the return valve sleeve; a accommodating chamber is formed between the main valve sleeve, the middle section of the main valve core and the return valve sleeve, and the working port and the liquid inlet are respectively connected to the accommodating chamber through corresponding through holes opened on the main valve sleeve; a through hole for communicating with the accommodating chamber is opened on the side wall of the middle section of the main valve core; the return valve core sliding sleeve is arranged on the main valve core and is located in the accommodating chamber.

[0007] According to a high water-based proportional valve of the present invention, the liquid return valve sleeve has an inner stepped structure and forms a limiting cavity with the rear section of the main valve core close to the middle section to achieve positioning of the liquid return valve core on the main valve core.

[0008] The present invention also provides a control system of a high water-based proportional valve based on the above-mentioned embodiment, comprising a pressure source, a liquid return control valve, a first high-speed switch valve, a second high-speed switch valve, a third high-speed switch valve, a fourth high-speed switch valve, an electronic control unit and the high water-based proportional valve; the electronic control unit is respectively connected to and controls the liquid return control valve, the first high-speed switch valve, the second high-speed switch valve, the third high-speed switch valve and the fourth high-speed switch valve; the pressure of the liquid return control port of the high water-based proportional valve is controlled by the liquid return control valve; the left control port of the high water-based proportional valve is controlled by the first high-speed switch valve and the second high-speed switch valve; the right control port of the high water-based proportional valve is controlled by the third high-speed switch valve and the fourth high-speed switch valve.

[0009] According to a control system of a high water-based proportional valve of the present invention, the electronic control unit includes a signal input device, an LVDT sensor, a first PD controller, a first judgment function module, a first P controller, a second PD controller, a second judgment function module, a second P controller, a first PWM signal device, a second PWM signal device, a third PWM signal device, and a fourth PWM signal device; the signal input device is used to send an input signal to the LVDT sensor or the liquid return control valve; the LVDT sensor or the liquid return control valve is started after receiving the signal from the signal input device; the LVDT sensor is used to calculate the valve core displacement error e, and the valve core displacement error e is divided into four signals to control the first high-speed switch valve, the second high-speed switch valve, the third high-speed switch valve and the fourth high-speed switch valve respectively; wherein The error signal of the first branch passes through the first PD controller to the first judgment function module, and then the first judgment function module outputs the duty cycle to the first PWM signal device, thereby controlling the first high-speed switch valve; the error signal of the second branch enters the first P controller after being reversed, and the first P controller adjusts the duty cycle of the second high-speed switch valve by controlling the second PWM signal device; the error signal of the third branch passes through the second PD controller to the second judgment function module after being reversed, and then the second judgment function module outputs the duty cycle to the third PWM signal device, thereby controlling the third high-speed switch valve; the error signal of the fourth branch directly enters the second P controller, and the second P controller adjusts the duty cycle of the fourth high-speed switch valve by controlling the fourth PWM signal device.

[0010] The present invention also provides a pulsation-free control method for a control system of a high water-based proportional valve based on the above-mentioned embodiment, comprising the following steps: inputting a signal r through the signal input device; when the signal r input by the signal input device is 0, the liquid return control valve is energized, the liquid return control port is connected to the liquid return flow path, and the liquid return valve core is pushed to the leftmost end under the pressure of the working port, at which time the liquid return port is connected to the working port, and the high water-based proportional valve is in the AT working state; when the signal r input by the signal input device is not 0, the liquid return control valve loses power, the LVDT sensor is energized, and the pressures of the left control port and the right control port are controlled by the control system of the high water-based proportional valve.

[0011] According to a pulsation-free control method of the present invention, in the step of controlling the pressures of the left control port and the right control port through the control system of the high water-based proportional valve, the step includes: calculating the valve core displacement error e; when the valve core displacement error e is greater than 0, controlling the pressure increase of the left control port and the pressure decrease of the right control port through the control system of the high water-based proportional valve, thereby realizing the rightward movement of the main valve core; when the valve core displacement error e is less than 0, controlling the pressure decrease of the left control port and the pressure increase of the right control port through the control system of the high water-based proportional valve, thereby realizing the leftward movement of the main valve core; when the valve core displacement error e is equal to 0, controlling the right control port to form a dead cavity through the control system of the high water-based proportional valve, so that the main valve core is locked.

[0012] According to a pulsation-free control method of the present invention, the step of controlling the pressure increase of the left control port and the pressure decrease of the right control port through the control system of the high-water-based proportional valve, thereby realizing the rightward movement of the main valve core, includes: the first error signal passes through the first PD controller to the first judgment function module, outputs the duty cycle to the first PWM signal device, and controls the duty cycle of the first high-speed switch valve to increase; the second error signal enters the first P controller after being inverted, and the duty cycle of the second high-speed switch valve is reduced through the second PWM signal device; the third error signal passes through the second judgment function module, so that the duty cycle of the third high-speed switch valve is 0 and remains in a closed state; the fourth error signal passes through the second P controller, so that the duty cycle of the fourth high-speed switch valve increases.

[0013] According to a pulsation-free control method of the present invention, the control system of the high-water-based proportional valve controls the pressure drop at the left control port and the pressure increase at the right control port, thereby realizing the step of moving the main valve core to the left, including: the first error signal passes through the first judgment function module, so that the duty cycle of the first high-speed switch valve is 0 and remains in a closed state; the second error signal enters the first P controller after being inverted, so that the duty cycle of the second high-speed switch valve increases; the third error signal enters the second judgment function module from the second PD controller after being inverted, outputs the duty cycle to the third PWM signal device, and controls the duty cycle of the third high-speed switch valve to increase; the fourth error signal enters the second P controller, and the duty cycle of the fourth high-speed switch valve is reduced by controlling the fourth PWM signal device.

[0014] According to a pulsation-free control method of the present invention, in the step of controlling the right control port to form a dead cavity through the control system of the high-water-based proportional valve so that the main valve core is locked, the steps include: the PWM signals of the second, third and fourth outputs are all 0, so that the second high-speed switch valve, the third high-speed switch valve and the fourth high-speed switch valve are all closed; the right control port forms a dead cavity, the main valve core is locked and cannot move, so that the main valve core stops without fluctuation after reaching the target position.

[0015] The high water-based proportional valve and its control system and pulsation-free control method provided by the present invention can realize fine control of valve core displacement through the three-stage design of the main valve core and the precise matching between the main valve core and the main valve sleeve and the return valve sleeve, thereby reducing the displacement pulsation caused by the switching frequency or pressure fluctuation, thereby improving the stability of control. The left control port and the right control port respectively apply forces in opposite directions to the main valve core, which helps to balance the pressure on both sides of the valve core and reduce the impact of the valve core during movement. By directly using fluid pressure to control the valve core instead of relying on complex electronic or electrical control circuits, the scheme of the present invention simplifies the design of the control system, reduces the debugging and maintenance costs, and also reduces the potential safety hazards caused by electrical components. The liquid entering the return control port applies pressure through the return valve core, which is combined with the displacement of the main valve core to achieve stepless and smooth flow regulation. The coordinated work of the fast-responding return valve core and the main valve core enables the hydraulic system to quickly adapt to changes in working conditions, ensures the stability and response speed of the hydraulic support under various load conditions, and improves the accuracy of posture control. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is one of the cross-sectional structural schematic diagrams of the high water-based proportional valve provided by the present invention.

[0018] Figure 2 This is the second schematic cross-sectional structure diagram of the high water-based proportional valve provided by the present invention.

[0019] Figure 3 It is a schematic diagram of the connection principle of the control system of the high water-based proportional valve provided by the present invention.

[0020] Figure 4 It is a schematic diagram of the process principle of the pulsation-free control method provided by the present invention.

[0021] Reference numerals: 1. Valve body; 2. Main valve sleeve; 3. Liquid return valve sleeve; 4. Main valve core; 5. Liquid return valve core; 6. Main spring; 1.1. Liquid return control port; 1.2. Liquid inlet; 1.3. Right control port; 1.4. Liquid return port; 1.5. Left control port; 1.6. Working port; 7. Liquid return control valve; 8. First high-speed switch valve; 9. Second high-speed switch valve; 10. Third high-speed switch valve; 11. Fourth high-speed switch valve; 12. Signal input device; 13. LVDT sensor; 14. First PD controller; 15. First judgment function module; 16. First PWM signal device; 17. First P controller; 18. Second PWM signal device; 19. Second PD controller; 20. Second judgment function module; 21. Third PWM signal device; 22. Second P controller; 23. Fourth PWM signal device; 24. Third judgment function module. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "set", "install", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0024] Combine the following Figure 1 and Figure 2 A specific embodiment of the high water-based proportional valve of the present invention is described.

[0025] The present invention provides a high water-based proportional valve, comprising a valve body 1, wherein a cavity penetrating the valve body 1 is provided inside the valve body 1, and the cavity is divided into a front end portion and a rear end portion, wherein the front end portion of the cavity is used as a liquid return port 1.4, and the rear end portion of the cavity is used to arrange a liquid return valve core 5, a main spring 6, a main valve core 4, a liquid return valve sleeve 3, and a main valve sleeve 2. A liquid return control port 1.1, a liquid inlet 1.2, a right control port 1.3, a working port 1.6, and a left control port 1.5, which are connected to the rear end portion of the cavity, are provided on the side of the valve body 1. The front end of the main valve sleeve 2 is sleeved on the front section of the main valve core 4, and the rear end of the main valve sleeve 2 is sleeved on the liquid return valve sleeve 3, and the main valve sleeve 2 is provided with through holes corresponding to the liquid return control port 1.1, the liquid inlet 1.2, the right control port 1.3, the working port 1.6, and the left control port 1.5. The liquid entering from the left control port 1.5 and the right control port 1.3 respectively exerts rightward and leftward forces on the main valve core 4 through the corresponding through holes on the main valve sleeve 2. The liquid entering from the liquid return control port 1.1 exerts rightward force on the liquid return valve core 5 through the corresponding through holes on the main valve sleeve 2 and the through holes on the liquid return valve sleeve 3.

[0026] Specifically, the high water-based proportional valve of the present invention aims to overcome the problems of unstable control and large valve core displacement pulsation of the high water-based proportional valve in the prior art through the above structure, realize stepless and smooth adjustment of the flow of the hydraulic system, improve the control accuracy of the hydraulic support posture and the safety and reliability of the hydraulic system in dangerous places such as coal mines. Among them, the cavity inside the valve body 1 is divided into two parts, the front end is used as the return liquid port 1.4 (T port), and the rear end accommodates the return liquid valve core 5, the main spring 6, the main valve core 4, the return liquid valve sleeve 3 and the main valve sleeve 2, forming an integrated control unit. The side of the valve body 1 is provided with a return liquid control port 1.1 (K3 port), a liquid inlet port 1.2 (P port), a right control port 1.3 (K2 port), a working port 1.6 (A port) and a left control port 1.5 (K1 port). These interfaces are connected to the internal cavity through the through hole on the main valve sleeve 2, so that the liquid can apply pressure or guide the reflux at different positions, thereby realizing the precise control of the valve core. The main valve core 4 has a hollow structure and is divided into three sections: front, middle and rear. This not only reduces the weight and volume of the valve core, but also improves the control stability of the proportional valve. The displacement of the main valve core 4 is controlled by the combined action of the pressure of the left control port 1.5 and the right control port 1.3 and the main spring 6. The liquid return valve core 5 is located in the accommodating cavity formed between the main valve core 4 and the liquid return valve sleeve 3. When the liquid entering from the liquid return control port 1.1 passes through the through holes on the main valve sleeve 2 and the liquid return valve sleeve 3, it will exert a rightward force on the liquid return valve core 5, affecting its opening and closing state, thereby controlling the liquid return path.

[0027] According to a high water-based proportional valve of the present invention, the main valve core 4 includes a coaxial front section, a middle section and a rear section, the front section of the main valve core 4 is a cylindrical hollow structure, and a main spring 6 is arranged inside the cylindrical hollow structure. Among them, the radius of the middle section and the rear section of the main valve core 4 is smaller than the radius of the front section of the main valve core 4, and the middle section of the main valve core 4 is hollow. The rear section of the main valve core 4 is sleeved with a return valve sleeve 3. A receiving chamber is formed between the main valve sleeve 2, the middle section of the main valve core 4 and the return valve sleeve 3, and the working port 1.6 and the liquid inlet 1.2 are respectively connected to the receiving chamber through corresponding through holes opened on the main valve sleeve 2. A through hole for communicating with the receiving chamber is opened on the side wall of the middle section of the main valve core 4. The return valve core 5 is slidably sleeved on the main valve core 4 and is located in the receiving chamber. The layout of the main valve core 4 and the liquid return valve core 5, combined with the composite action of the main spring 6, enables the high water-based proportional valve of the present invention to achieve precise control of liquid flow, reduce valve core displacement pulsation, and improve control stability and response speed. In addition, the design of the hollow structure also helps to reduce the weight of the valve core, reduce energy consumption, and improve the overall efficiency and reliability of the proportional valve.

[0028] Specifically, the front section of the main valve core 4 is set as a cylindrical hollow structure, and the hollow part is used to place the main spring 6, which helps to achieve effective arrangement of the spring in a limited space, while maintaining the structural strength and lightness of the main valve core 4. The diameter of the middle section and the rear section of the main valve core 4 is smaller than that of the front section, and the middle section is also a hollow structure. The rear section is sleeved with a return valve sleeve 3, so that the relative movement between the main valve core 4 and the return valve sleeve 3 is smoother, and the hollow design of the middle section is conducive to the circulation of liquid. The space formed by the main valve sleeve 2, the middle section of the main valve core 4 and the return valve sleeve 3 is called the accommodating chamber, which serves as the key path for liquid flow. The through hole on the side wall of the middle section of the main valve core 4 and the through hole on the main valve sleeve 2 are used to connect the working port 1.6 (port A), the liquid inlet 1.2 (port P) and the accommodating chamber. The return valve core 5 is slidably sleeved on the main valve core 4 and is located inside the accommodating chamber. The movement of the liquid return valve core 5 is controlled by the liquid pressure from the liquid return control port 1.1 (K3 port). Its position can be changed through the through holes on the main valve sleeve 2 and the liquid return valve sleeve 3, thereby controlling the liquid return path and affecting the working state of the entire proportional valve.

[0029] According to a high water-based proportional valve of the present invention, the liquid return valve sleeve 3 has an inner step structure and forms a limit cavity with the rear section of the main valve core 4 near the middle section to realize the positioning of the liquid return valve core 5 on the main valve core 4. The function of the limit cavity is to limit the lateral and longitudinal movement of the liquid return valve core 5 to ensure that it can accurately move to a predetermined position when subjected to fluid pressure without excessive displacement or vibration. Among them, the inner step on the inner surface of the liquid return valve sleeve 3 can form a mechanical limit. When the liquid return valve sleeve 3 is installed on the main valve core 4, its inner step fits tightly with the rear section of the main valve core 4 near the middle section, and the space between the two constitutes a limit cavity to match the size and range of motion of the liquid return valve core 5.

[0030] Combine the following Figure 1 , Figure 2 and Figure 3 The control system of the high water-based proportional valve provided by the present invention is described. The control system of the high water-based proportional valve described below and the high water-based proportional valve described above can correspond to each other.

[0031] The present invention also provides a control system of a high water-based proportional valve based on the above-mentioned embodiment, comprising a pressure source, a liquid return control valve 7, a first high-speed switch valve 8, a second high-speed switch valve 9, a third high-speed switch valve 10, a fourth high-speed switch valve 11, an electronic control unit and a high water-based proportional valve. The electronic control unit is respectively connected to and controls the liquid return control valve 7, the first high-speed switch valve 8, the second high-speed switch valve 9, the third high-speed switch valve 10 and the fourth high-speed switch valve 11. The liquid inlet 1.2, the left control port 1.5, the right control port 1.3 and the liquid return control port 1.1 of the high water-based proportional valve are all connected to the pressure source. A liquid return control valve 7 is provided between the liquid return control port 1.1 of the high water-based proportional valve and the pressure source, and the pressure of the liquid return control port 1.1 of the high water-based proportional valve is controlled by the liquid return control valve 7. The left control port 1.5 of the high water-based proportional valve is controlled by the first high-speed switch valve 8 and the second high-speed switch valve 9. The right control port 1.3 of the high water-based proportional valve is controlled by the third high-speed switch valve 10 and the fourth high-speed switch valve 11.

[0032] Among them, the pressure source provides the pressure liquid required by the system, usually a pump or other form of liquid pressure supply device. The return liquid control valve 7 is used to control the pressure of the return liquid control port 1.1 (K3 port), affecting the opening and closing of the return liquid valve core 5, thereby controlling the return liquid path. The high-speed switch valve is used to quickly switch the pressure of the left control port 1.5 (K1 port) and the right control port 1.3 (K2 port), so as to accurately control the left and right movement of the main valve core 4 and realize the flow regulation of the proportional valve. The electronic control unit is responsible for receiving sensor signals, processing data, and sending instructions to the return liquid control valve 7 and the four high-speed switch valves to realize dynamic control of the high water-based proportional valve.

[0033] The liquid inlet 1.2 (P port), the left control port 1.5 (K1 port), the right control port 1.3 (K2 port) and the liquid return control port 1.1 (K3 port) of the high water-based proportional valve are all connected to the pressure source to ensure sufficient pressure supply. Through the liquid return control valve 7, the electronic control unit can accurately adjust the pressure of the liquid return control port 1.1, thereby affecting the movement of the liquid return valve core 5 and controlling the opening and closing of the liquid return path. The left control port 1.5 is controlled by the first high-speed switch valve 8 and the second high-speed switch valve 9, while the right control port 1.3 is controlled by the third high-speed switch valve 10 and the fourth high-speed switch valve 11. By quickly switching the states of these high-speed switch valves, the electronic control unit can adjust the pressure difference on both sides of the main valve core 4 in real time, control the displacement of the main valve core 4, and realize stepless and smooth regulation of the flow rate.

[0034] According to a control system of a high water-based proportional valve of the present invention, the electronic control unit preferably includes a signal input device 12, an LVDT sensor 13, a first PD controller 14, a first judgment function module 15, a first P controller 17, a second PD controller 19, a second judgment function module 20, a second P controller 22, a first PWM signal device 16, a second PWM signal device 18, a third PWM signal device 21, and a fourth PWM signal device 23; the signal input device 12 is used to send the input signal to the LVDT sensor 13 or the liquid return control valve 7.

[0035] Specifically, the LVDT sensor 13 or the liquid return control valve 7 is started after receiving the signal from the signal input device 12. The LVDT sensor 13 is used to calculate the valve core displacement error e, and divide the valve core displacement error e into four signals to control the first high-speed switch valve 8, the second high-speed switch valve 9, the third high-speed switch valve 10 and the fourth high-speed switch valve 11 respectively. Among them, the error signal of the first branch is sent to the first judgment function module 15 through the first PD controller 14, and then the first judgment function module 15 outputs the duty cycle to the first PWM signal device 16, thereby controlling the first high-speed switch valve 8. The error signal of the second branch is reversed and enters the first P controller 17, and the first P controller 17 adjusts the duty cycle of the second high-speed switch valve 9 by controlling the second PWM signal device 18. The error signal of the third branch is reversed and sent to the second judgment function module 20 through the second PD controller 19, and then the second judgment function module 20 outputs the duty cycle to the third PWM signal device 21, thereby controlling the third high-speed switch valve 10. The error signal of the fourth branch directly enters the second P controller 22 , and the second P controller 22 adjusts the duty cycle of the fourth high-speed switching valve 11 by controlling the fourth PWM signal device 23 .

[0036] Combine the following Figure 1 , Figure 2 , Figure 3 and Figure 4The pulsation-free control method provided by the present invention is described. The pulsation-free control method described below and the high water-based proportional valve and the control system of the high water-based proportional valve described above can be referred to each other. In the description of the present invention, the side where the return liquid port 1.4 of the valve body 1 is located is the right side, and the side away from the return liquid port 1.4 is the left side.

[0037] The present invention also provides a pulsation-free control method for a control system of a high-water-based proportional valve based on the above-mentioned embodiment. The method utilizes the real-time feedback of the LVDT sensor 13 and dynamically adjusts the control pressure on both sides of the valve through a precise PID control algorithm (PD and P controllers are particularly mentioned here) to ensure smooth and continuous flow of the fluid inside the valve and avoid pulsation or vibration caused by sudden pressure changes.

[0038] The pulsation-free control method specifically includes the following steps: inputting a signal r through a signal input device 12; when the signal r input by the signal input device 12 is 0, the liquid return control valve 7 is energized, the liquid return control port 1.1 is connected to the liquid return flow path, and the liquid return valve core 5 is pushed to the leftmost end under the pressure of the working port 1.6. At this time, the liquid return port 1.4 is connected to the working port 1.6, and the high water base proportional valve is in the AT working state; when the signal r input by the signal input device 12 is not 0, the liquid return control valve 7 loses power, the LVDT sensor 13 is energized, and the pressure of the left control port 1.5 and the right control port 1.3 is controlled by the control system of the high water base proportional valve.

[0039] Specifically, when the signal input device 12 does not receive any input signal (i.e., the signal r is 0), the system is in the default standby state. At this time, the liquid return control valve 7 is energized. The liquid return flow path is connected to the liquid return control port 1.1, allowing liquid to flow. Under the pressure of the working port 1.6, the liquid return valve core 5 is pushed to the far left end to ensure that the liquid return port 1.4 is connected to the working port 1.6. The high water base proportional valve is in the AT working state, allowing the fluid to flow from the working port 1.6 to the liquid return port 1.4, maintaining the preset circulation state.

[0040] When the signal input device 12 receives a non-zero signal r, the system needs to be controlled. At this time, the return liquid control valve 7 loses power. The LVDT sensor 13 is powered and starts working, measuring the displacement of the valve core and providing a feedback signal. The left control port 1.5 and the right control port 1.3 adjust the pressure through the control system of the high water-based proportional valve. According to the feedback signal provided by the LVDT sensor 13, the pressure of the left control port 1.5 and the right control port 1.3 is adjusted through mechanisms such as the PD controller and the P controller to achieve the desired fluid control effect.

[0041] According to a pulsation-free control method of the present invention, the pressure of the left control port 1.5 (K1 port) and the right control port 1.3 (K2 port) is precisely controlled by the control system of the high water-based proportional valve to achieve seamless adjustment of the displacement of the main valve core 4 and ensure the smooth operation of the entire hydraulic system. In the above step of controlling the pressure of the left control port 1.5 and the right control port 1.3 by the control system of the high water-based proportional valve, it includes: calculating the valve core displacement error e; when the valve core displacement error e is greater than 0, the pressure of the left control port 1.5 is controlled to rise and the pressure of the right control port 1.3 is controlled to drop by the control system of the high water-based proportional valve, so as to achieve the rightward movement of the main valve core 4; when the valve core displacement error e is less than 0, the pressure of the left control port 1.5 is controlled to drop and the pressure of the right control port 1.3 is controlled to rise, so as to achieve the leftward movement of the main valve core 4; when the valve core displacement error e is equal to 0, the right control port 1.3 is controlled by the control system of the high water-based proportional valve to form a dead cavity, so that the main valve core 4 is locked.

[0042] Specifically, first, the actual displacement of the main valve core 4 is measured by the LVDT sensor 13, and compared with the target displacement to calculate the valve core displacement error e. The error value reflects the deviation between the current position of the main valve core 4 and the expected position.

[0043] When the valve core displacement error e is greater than 0, it means that the position of the main valve core 4 is further to the left than expected and needs to be moved to the right to reach the target position. By increasing the pressure of the left control port 1.5 (K1 port) and reducing the pressure of the right control port 1.3 (K2 port), the main valve core 4 is moved to the right until the error is reduced to zero.

[0044] When the valve core displacement error e is less than 0, the position of the main valve core 4 is more to the right than expected and needs to be moved to the left. The control system reduces the pressure of the left control port 1.5 (K1 port) and increases the pressure of the right control port 1.3 (K2 port) to move the main valve core 4 to the left to reduce the error until it returns to zero.

[0045] When the valve core displacement error e is equal to 0, the main valve core 4 has reached the target position and does not need to be moved further. The control system forms a "dead cavity" state by controlling the right control port 1.3 (K2 port), that is, a certain pressure is maintained, but there is no flow change, which effectively locks the position of the main valve core 4 and prevents it from moving due to slight pressure fluctuations in the system, ensuring the stability and control accuracy of the system.

[0046] Through the above-mentioned precise pressure adjustment, the control method can effectively eliminate or significantly reduce the pulsation phenomenon of the main valve core 4 during the movement process, ensure the smooth operation of the hydraulic system, and improve the accuracy and response speed of flow control.

[0047] According to a pulsation-free control method of the present invention, the control system of the high-water-based proportional valve controls the pressure increase of the left control port 1.5 and the pressure decrease of the right control port 1.3, thereby realizing the step of the main valve core 4 moving to the right, including: the first error signal passes through the first PD controller 14 to the first judgment function module 15, outputs the duty cycle to the first PWM signal device 16, and controls the first high-speed switch valve 8 to increase the duty cycle; the second error signal enters the first P controller 17 after being inverted, and reduces the duty cycle of the second high-speed switch valve 9 through the second PWM signal device 18; the third error signal passes through the second judgment function module 20, so that the duty cycle of the third high-speed switch valve 10 is 0 and remains in a closed state; the fourth error signal passes through the second P controller 22, so that the duty cycle of the fourth high-speed switch valve 11 increases.

[0048] Specifically, when the valve core displacement error e is greater than 0, the main valve core 4 needs to move to the right. At this time, the first error signal passes through the first PD controller 14 to the first judgment function module 15, and then outputs the duty cycle to the first PWM signal device 16 to control the first high-speed switch valve 8 to increase the duty cycle. At the same time, the second error signal enters the first P controller 17 after being inverted, and the duty cycle of the second high-speed switch valve 9 is reduced through the second control PWM signal device. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the left control port 1.5 rises. Under the action of the second judgment function module 20, the third error signal makes the duty cycle of the third high-speed switch valve 10 0 and remain in a closed state. After the fourth error signal is acted on by the second P controller 22, the duty cycle of the fourth high-speed switch valve 11 is increased. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the right control port 1.3 drops to the pressure of the return liquid port 1.4; under the joint action of the pressure increase of the left control port 1.5 and the pressure drop of the right control port 1.3, the main valve core 4 moves to the right and the larger the valve core displacement error e, the faster the movement speed.

[0049] According to a pulsation-free control method of the present invention, the control system of the high-water-based proportional valve controls the pressure drop at the left control port 1.5 and the pressure increase at the right control port 1.3, thereby realizing the step of moving the main valve core 4 to the left, including: the first error signal passes through the first judgment function module 15, so that the duty cycle of the first high-speed switch valve 8 is 0 and remains in a closed state; the second error signal enters the first P controller 17 after being inverted, so that the duty cycle of the second high-speed switch valve 9 increases; the third error signal enters the second judgment function module 20 through the second PD controller 19 after being inverted, and outputs the duty cycle to the third PWM signal device 21, controlling the duty cycle of the third high-speed switch valve 10 to increase; the fourth error signal enters the second P controller 22, and the duty cycle of the fourth high-speed switch valve 11 is reduced by controlling the fourth PWM signal device 23.

[0050] Specifically, when the valve core displacement error e is less than 0, the main valve core 4 needs to move to the left. The first error signal, under the action of the first judgment function module 15, makes the duty cycle of the first high-speed switch valve 8 0 and remains in a closed state. The second error signal enters the first P controller 17 after being inverted, so that the duty cycle of the second high-speed switch valve 9 increases. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the left control port 1.5 drops to the pressure of the return liquid port 1.4. The third error signal enters the second judgment function module 20 from the second PD controller 19 after being inverted, and then outputs the duty cycle to the third PWM signal device 21 to control the duty cycle of the third high-speed switch valve 10 to increase. The fourth error signal directly enters the second P controller 22, and the duty cycle of the fourth high-speed switch valve 11 is reduced by controlling the fourth PWM signal device 23. Under the joint action of the third high-speed switch valve 10 and the fourth high-speed switch valve 11, the pressure of the right control port 1.3 rises; under the joint action of the pressure drop of the left control port 1.5 and the pressure increase of the right control port 1.3, the main valve core 4 moves to the left and the larger the valve core displacement error e, the faster the movement speed.

[0051] According to a pulsation-free control method of the present invention, in the step of controlling the right control port 1.3 to form a dead cavity through the control system of the high-water-based proportional valve so that the main valve core 4 is locked, the steps include: the PWM signals of the second, third and fourth outputs are all 0, so that the second high-speed switch valve 9, the third high-speed switch valve 10 and the fourth high-speed switch valve 11 are all closed; the right control port 1.3 forms a dead cavity, the main valve core 4 is locked and cannot move, so that the main valve core 4 stops without fluctuation after reaching the target position.

[0052] Specifically, when the valve core displacement error e is equal to 0, the PWM signals of the second, third and fourth outputs are all 0, so that the second high-speed switch valve 9, the third high-speed switch valve 10 and the fourth high-speed switch valve 11 are all closed; the right control port 1.3 forms a dead cavity, the main valve core 4 is locked and cannot move, so that the main valve core 4 stops without fluctuation after reaching the target position.

[0053] The present invention overcomes the flow pulsation problem existing in the existing high-speed switching valve pilot control by utilizing the volume dead cavity to lock the valve core. While retaining the advantages of the high-speed switching valve pilot control such as simple structure, low power consumption and fast response, the present invention realizes the stable flow output of the proportional valve pilot control.

[0054] According to a preferred embodiment of the present invention, when the above-mentioned high water-based proportional valve and its control system are combined with the pulsation-free control method, the operating principle is as follows: The main valve core 4 is threadedly connected with the liquid return valve sleeve 3 to form a hydraulically balanced valve core. The liquid pressure of the working port 1.6 acts on the left end of the main valve core 4 and the right end of the liquid return valve sleeve 3 at the same time. Since the areas of the two are the same, the liquid pressure cancels each other out. The liquid of the left control port 1.5 and the right control port 1.3 acts on the stepped surface of the main valve core 4 through the valve body 1 and the valve sleeve. The movement of the main valve core 4 and the liquid return valve sleeve 3 combination is controlled by the combined action of the pressure of the left control port 1.5 and the right control port 1.3 and the main spring 6.

[0055] When the pressure of the left control port 1.5 of the main valve core 4 and the liquid return valve sleeve 3 combination is insufficient or the pressure of the right control port 1.3 is too high, the liquid inlet 1.2 is blocked. At this time, the liquid return control valve 7 is energized, the liquid return control port 1.1 is connected to the liquid return, and the liquid return valve core 5 is pushed to the leftmost end under the pressure of the working port 1.6. At this time, the liquid return port 1.4 is connected to the working port 1.6, and the proportional valve is in the AT working state.

[0056] When the pressure of the left control port 1.5 on the main valve core 4 and the liquid return valve sleeve 3 combination is too high or the pressure of the right control port 1.3 is insufficient, the main valve core 4 moves to the right, the liquid inlet 1.2 is connected to the working port 1.6, so that the PA main valve port is opened. Different valve port areas correspond to different flow rates, and the main valve flow rate can be controlled by the pressure of the control port and finally. At this time, the liquid return control valve 7 loses power, the liquid return control port 1.1 is connected to the pressure source, and the liquid return valve core 5 is pushed to the rightmost end. At this time, the liquid return port 1.4 is not connected to the working port 1.6, and the proportional valve is in the PA working state.

[0057] The pressure of the left control port 1.5 is controlled by the first high-speed switch valve 8 and the second high-speed switch valve 9 to form a half-bridge control, and the pressure of the right control port 1.3 is controlled by the third high-speed switch valve 10 and the fourth high-speed switch valve 11 to form a half-bridge control. The control method is as follows: Figure 4 As shown. After the valve core displacement signal is given, when the given signal r is 0, the liquid return control valve 7 is energized, so that the proportional valve is in the AT working state. When the given signal r is not 0, the liquid return control valve 7 loses power. At the same time, the valve core displacement error e is obtained by negative feedback operation with the LVDT sensor 13, and the displacement error e is divided into four signals for operation.

[0058] When the valve core displacement error e is greater than 0, it means that the main valve core 4 needs to move to the right at this time. At this time, the first error signal passes through the first PD controller 14 to the first judgment function module 15, and then outputs the duty cycle to the first PWM signal device 16 to control the first high-speed switch valve 8 to increase the duty cycle. At the same time, the second error signal enters the first P controller 17 after being inverted, and the duty cycle of the second high-speed switch valve 9 is reduced by controlling the second PWM signal device 18. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the left control port 1.5 rises rapidly. Under the action of the second judgment function module 20, the third error signal makes the duty cycle of the third high-speed switch valve 10 0 and remains in a closed state. After the fourth error signal passes through the second P controller 22, the duty cycle of the fourth high-speed switch valve 11 increases. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the right control port 1.3 drops to the pressure of the return liquid port 1.4. Under the combined effect of the rapid increase in pressure at the left control port 1.5 and the decrease in pressure at the right control port 1.3, the main valve core 4 moves to the right, and the larger the valve core displacement error e, the faster the movement speed.

[0059] When the valve core displacement error e is less than 0, it means that the main valve core 4 needs to move to the left at this time. The first error signal, under the action of the first judgment function module 15, makes the duty cycle of the first high-speed switch valve 8 0 and remains in a closed state. The second error signal enters the first P controller 17 after being inverted, so that the duty cycle of the second high-speed switch valve 9 increases. Under the joint action of the first high-speed switch valve 8 and the second high-speed switch valve 9, the pressure of the left control port 1.5 drops to the pressure of the return liquid port 1.4. The third error signal enters the second judgment function module 20 through the second PD controller 19 after being inverted, and then outputs the duty cycle to the third PWM signal device 21 to control the duty cycle of the third high-speed switch valve 10 to increase. The fourth error signal directly enters the second P controller 22, and the duty cycle of the fourth high-speed switch valve 11 is reduced by controlling the fourth PWM signal device 23. Under the joint action of the third high-speed switch valve 10 and the fourth high-speed switch valve 11, the pressure of the right control port 1.3 rises rapidly. Under the combined effect of the rapid drop in pressure at the left control port 1.5 and the rapid rise in pressure at the right control port 1.3, the main valve core 4 moves to the left, and the larger the valve core displacement error e, the faster the movement speed.

[0060] When the valve core displacement error e is equal to 0, the PWM signals of the second, third and fourth outputs are all 0, so that the second high-speed switch valve 9, the third high-speed switch valve 10 and the fourth high-speed switch valve 11 are all closed. In this way, a dead cavity is formed at the right control port 1.3, the main valve core 4 is locked and cannot move, and the main valve core 4 stops without fluctuation after reaching the target position.

[0061] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high water-based proportional valve, characterized in that: include: A valve body (1), wherein a cavity is provided inside the valve body (1) and passes through the valve body (1), the cavity being divided into a front end portion and a rear end portion, the front end portion of the cavity being used as a liquid return port (1.4), and the rear end portion of the cavity being used to arrange a liquid return valve core (5), a main spring (6), a main valve core (4), a liquid return valve sleeve (3), and a main valve sleeve (2); The side surface of the valve body (1) is provided with a liquid return control port (1.1) which is communicated with the rear end portion of the cavity, a liquid inlet port (1.2), a right control port (1.3), a working port (1.6) and a left control port (1.5); The front end of the main valve sleeve (2) is sleeved on the front section of the main valve core (4), and the rear end of the main valve sleeve (2) is sleeved on the liquid return valve sleeve (3); the main valve sleeve (2) is provided with through holes corresponding to the liquid return control port (1.1), the liquid inlet port (1.2), the right control port (1.3), the working port (1.6) and the left control port (1.5); the liquid entering from the left control port (1.5) and the right control port (1.3) applies rightward and leftward forces to the main valve core (4) respectively through the corresponding through holes provided on the main valve sleeve (2); the liquid entering from the liquid return control port (1.1) passes through the corresponding through holes provided on the main valve sleeve (2) and the through holes on the liquid return valve sleeve (3), and applies a rightward force to the liquid return valve core (5).

2. The high water-based proportional valve according to claim 1, characterized in that: The main valve core (4) comprises a coaxial front section, a middle section and a rear section; the front section of the main valve core (4) is a cylindrical hollow structure, and the main spring (6) is arranged inside the cylindrical hollow structure; the radius of the middle section and the rear section of the main valve core (4) is smaller than the radius of the front section of the main valve core (4), and the middle section of the main valve core (4) is hollow; the rear section of the main valve core (4) is sleeved with the liquid return valve sleeve (3); A receiving chamber is formed between the main valve sleeve (2), the middle section of the main valve core (4) and the liquid return valve sleeve (3); the working port (1.6) and the liquid inlet (1.2) are respectively connected to the receiving chamber via corresponding through holes provided on the main valve sleeve (2); a through hole for connecting to the receiving chamber is provided on the side wall of the middle section of the main valve core (4); the liquid return valve core (5) is slidably sleeved on the main valve core (4) and is located in the receiving chamber.

3. The high water-based proportional valve according to claim 1, characterized in that: The liquid return valve sleeve (3) has an inner step structure and forms a limiting cavity with the rear section of the main valve core (4) close to the middle section, so as to realize the positioning of the liquid return valve core (5) on the main valve core (4).

4. A control system based on the high water-based proportional valve according to any one of claims 1 to 3, characterized in that: It comprises a pressure source, a liquid return control valve (7), a first high-speed switch valve (8), a second high-speed switch valve (9), a third high-speed switch valve (10), a fourth high-speed switch valve (11), an electronic control unit and the high-water-based proportional valve; The electronic control unit is respectively connected to the liquid return control valve (7), the first high-speed switch valve (8), the second high-speed switch valve (9), the third high-speed switch valve (10) and the fourth high-speed switch valve (11) to control them; The pressure of the liquid return control port (1.1) of the high water base proportional valve is controlled by the liquid return control valve (7); the left control port (1.5) of the high water base proportional valve is controlled by the first high-speed switch valve (8) and the second high-speed switch valve (9); and the right control port (1.3) of the high water base proportional valve is controlled by the third high-speed switch valve (10) and the fourth high-speed switch valve (11).

5. The control system of the high water-based proportional valve according to claim 4, characterized in that: The electronic control unit comprises a signal input device (12), an LVDT sensor (13), a first PD controller (14), a first judgment function module (15), a first P controller (17), a second PD controller (19), a second judgment function module (20), a second P controller (22), a first PWM signal device (16), a second PWM signal device (18), a third PWM signal device (21), and a fourth PWM signal device (23); The signal input device (12) is used to send an input signal to the LVDT sensor (13) or the liquid return control valve (7); the LVDT sensor (13) or the liquid return control valve (7) is started after receiving the signal from the signal input device (12); the LVDT sensor (13) is used to calculate the valve core displacement error e, and divide the valve core displacement error e into four signals to respectively control the first high-speed switch valve (8), the second high-speed switch valve (9), the third high-speed switch valve (10) and the fourth high-speed switch valve (11); The error signal of the first branch is transmitted through the first PD controller (14) to the first judgment function module (15), and then the first judgment function module (15) outputs the duty cycle to the first PWM signal device (16), thereby controlling the first high-speed switch valve (8); the error signal of the second branch is inverted and then enters the first P controller (17), and the first P controller (17) adjusts the duty cycle of the second high-speed switch valve (9) by controlling the second PWM signal device (18); the error signal of the third branch is inverted and then passes through the second PD controller (19) to the second judgment function module (20), and then the second judgment function module (20) outputs the duty cycle to the third PWM signal device (21), thereby controlling the third high-speed switch valve (10); the error signal of the fourth branch directly enters the second P controller (22), and the second P controller (22) adjusts the duty cycle of the fourth high-speed switch valve (11) by controlling the fourth PWM signal device (23).

6. A pulsation-free control method for a control system based on the high water-based proportional valve according to claim 5, characterized in that: The following steps are involved: Inputting a signal r through the signal input device (12); When the signal r input by the signal input device (12) is 0, the liquid return control valve (7) is energized, the liquid return control port (1.1) is connected to the liquid return flow path, the liquid return valve core (5) is pushed to the leftmost end under the pressure of the working port (1.6), and the liquid return port (1.4) is connected to the working port (1.6), and the high water base proportional valve is in the AT working state; When the signal r input by the signal input device (12) is not 0, the liquid return control valve (7) loses power, the LVDT sensor (13) gains power, and the pressures of the left control port (1.5) and the right control port (1.3) are controlled through the control system of the high water-based proportional valve.

7. The pulsation-free control method according to claim 6, characterized in that: The step of controlling the pressure of the left control port (1.5) and the right control port (1.3) through the control system of the high water-based proportional valve comprises: Calculate the valve core displacement error e; When the valve core displacement error e is greater than 0, the pressure of the left control port (1.5) is controlled to increase and the pressure of the right control port (1.3) is controlled to decrease through the control system of the high water-based proportional valve, thereby achieving the rightward movement of the main valve core (4); When the valve core displacement error e is less than 0, the control system of the high water-based proportional valve controls the pressure drop at the left control port (1.5) and the pressure increase at the right control port (1.3), thereby achieving the leftward movement of the main valve core (4); When the valve core displacement error e is equal to 0, the control system of the high water-based proportional valve controls the right control port (1.3) to form a dead space, so that the main valve core (4) is locked.

8. The pulsation-free control method according to claim 7, characterized in that: The step of controlling the pressure increase of the left control port (1.5) and the pressure decrease of the right control port (1.3) through the control system of the high water-based proportional valve, thereby achieving the rightward movement of the main valve core (4), comprises: The first error signal is transmitted through the first PD controller (14) to the first judgment function module (15), and the duty cycle is output to the first PWM signal device (16), so as to control the duty cycle of the first high-speed switch valve (8) to increase; The second error signal is inverted and enters the first P controller (17), and the duty cycle of the second high-speed switch valve (9) is reduced through the second PWM signal device (18); The third error signal passes through the second judgment function module (20), so that the duty cycle of the third high-speed switch valve (10) is 0 and remains in a closed state; The fourth error signal passes through the second P controller (22), thereby increasing the duty cycle of the fourth high-speed switching valve (11).

9. The pulsation-free control method according to claim 7, characterized in that: The step of controlling the pressure drop at the left control port (1.5) and the pressure increase at the right control port (1.3) by the control system of the high water-based proportional valve, thereby achieving the leftward movement of the main valve core (4), comprises: The first error signal passes through the first judgment function module (15), so that the duty cycle of the first high-speed switch valve (8) is 0 and remains in a closed state; The second error signal is inverted and enters the first P controller (17), so that the duty cycle of the second high-speed switch valve (9) increases; The third error signal is inverted and then enters the second judgment function module (20) from the second PD controller (19), outputs the duty cycle to the third PWM signal device (21), and controls the duty cycle of the third high-speed switch valve (10) to increase; The fourth error signal enters the second P controller (22), and controls the fourth PWM signal device (23) so that the duty cycle of the fourth high-speed switch valve (11) is reduced.

10. The pulsation-free control method according to claim 7, characterized in that: The step of controlling the right control port (1.3) to form a dead space through the control system of the high water-based proportional valve so that the main valve core (4) is locked includes: The PWM signals of the second, third and fourth outputs are all 0, so that the second high-speed switch valve (9), the third high-speed switch valve (10) and the fourth high-speed switch valve (11) are all closed; The right control port (1.3) forms a dead space, and the main valve core (4) is locked and cannot move, so that the main valve core (4) stops without fluctuation after reaching the target position.

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