High water-based proportional valve, control system and pulseless control method thereof

Abstract

The present application relates to the technical field of valve, especially to a high water-based proportional valve, a control system thereof and a non-pulsation control method. The high water-based 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 port, and the rear end part of the cavity is used for arranging 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 port, a right control port, a working port and a left control port in communication with the rear end part of the cavity are formed in the side surface 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 port, the right control port, the working port and the left control port. The present application is used to realize stepless smooth adjustment of the flow of a hydraulic system, improve the posture control precision of a hydraulic support, and enhance the safety and reliability of a hydraulic system in dangerous occasions such as coal mines.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of valves, in particular to a high water-based proportional valve, a control system thereof and a pulse-free control method. BACKGROUND

[0002] In coal mines and other high-risk environments, the safety and efficiency of hydraulic systems are of great importance. Currently, high water-based proportional valves, as the key to flow regulation in pure water or emulsion medium, play an irreplaceable role in achieving precise control of hydraulic systems and improving explosion-proof performance. However, the limitations of traditional on-off valve control, especially the problem of hydraulic cylinder overextension or over-retraction, seriously affect the fine posture management of hydraulic supports, thereby threatening operational safety.

[0003] In the prior art, high water-based proportional valves are generally divided into three categories according to control methods: high-speed on-off valve pilot type, which is limited by on-off frequency and is prone to cause valve core displacement fluctuations, damaging system stability; motor pilot type, which faces the problem of difficulty in meeting the requirements of intrinsic safety and implies potential risks; and balanced type controlled by pilot pressure reducing valve, which excessively relies on the performance of pressure reducing valves, increases the difficulty of design and debugging, and hinders popular application. SUMMARY

[0004] The present application provides a high water-based proportional valve, a control system thereof and a pulse-free control method to solve the defects of unstable control, large valve core displacement pulsation, difficulty in ensuring intrinsic safety and high design and debugging complexity of high water-based proportional valves in the prior art, and to achieve stepless smooth regulation of hydraulic system flow, improve the posture control accuracy of hydraulic supports, and enhance the safety and reliability of hydraulic systems in dangerous environments such as coal mines.

[0005] The present application provides a high water-based proportional valve, comprising: a valve body, a cavity through the valve body is formed inside the valve body, the cavity is divided into a front end portion and a rear end portion, the front end portion of the cavity serves as a liquid return port, and the rear end portion 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 port, a right control port, a working port and a left control port are formed on the side surface of the valve body and communicate with the rear end portion of the cavity; the main valve sleeve is sleeved on the front end 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 port, 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 respectively applies rightward and leftward forces to the main valve core through the corresponding through holes formed on the main valve sleeve; the liquid entering from the liquid return control port applies a rightward force to the liquid return valve core through the corresponding through holes formed on the main valve sleeve and the through hole 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 divide the valve core displacement error e 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 switching valve; the error signal of the second branch enters the first P controller after being inverted, and the first P controller adjusts the duty cycle of the second high-speed switching 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 inverted, and then the second judgment function module outputs the duty cycle to the third PWM signal device, thereby controlling the third high-speed switching 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 switching 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 this 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 the pulse-free control method, in the step of controlling the pressure of the left control port and the right control port by the control system of the high water-based proportional valve, the valve core displacement error e is calculated; when the valve core displacement error e is greater than 0, the pressure of the left control port is increased and the pressure of the right control port is decreased by the control system of the high water-based proportional valve, so that the main valve core moves to the right; when the valve core displacement error e is less than 0, the pressure of the left control port is decreased and the pressure of the right control port is increased by the control system of the high water-based proportional valve, so that the main valve core moves to the left; and when the valve core displacement error e is equal to 0, the right control port is controlled to form a dead space by the control system of the high water-based proportional valve, so that the main valve core is locked.

[0012] According to the pulse-free control method, in the step of controlling the pressure of the left control port and the right control port by the control system of the high water-based proportional valve, the valve core displacement error e is calculated; when the valve core displacement error e is greater than 0, the pressure of the left control port is increased and the pressure of the right control port is decreased by the control system of the high water-based proportional valve, so that the main valve core moves to the right; when the valve core displacement error e is less than 0, the pressure of the left control port is decreased and the pressure of the right control port is increased by the control system of the high water-based proportional valve, so that the main valve core moves to the left; and when the valve core displacement error e is equal to 0, the right control port is controlled to form a dead space by the control system of the high water-based proportional valve, so that the main valve core is locked.

[0013] According to the pulse-free control method, in the step of controlling the pressure of the left control port and the right control port by the control system of the high water-based proportional valve, the valve core displacement error e is calculated; when the valve core displacement error e is greater than 0, the pressure of the left control port is increased and the pressure of the right control port is decreased by the control system of the high water-based proportional valve, so that the main valve core moves to the right; when the valve core displacement error e is less than 0, the pressure of the left control port is decreased and the pressure of the right control port is increased by the control system of the high water-based proportional valve, so that the main valve core moves to the left; and when the valve core displacement error e is equal to 0, the right control port is controlled to form a dead space by the control system of the high water-based proportional valve, so that the main valve core is locked.

[0014] According to a pulsation-free control method of the present invention, in the step of controlling the right control port through the control system of the high-water-based proportional valve to form a dead space so that the main valve core is locked, the method includes: the PWM signals of the second, third, and fourth outputs are all 0, so that the second high-speed switching valve, the third high-speed switching valve, and the fourth high-speed switching valve are all closed; the right control port forms a dead space, 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 present invention provides a high-water-base proportional valve, its control system, and pulsation-free control method. The high-water-base proportional valve utilizes a three-stage design of the main valve core and precise coordination between the main valve core, the main valve sleeve, and the return valve sleeve. This allows for precise control of valve core displacement, reducing displacement pulsation caused by switching frequency or pressure fluctuations, thereby improving control stability. The left and right control ports apply opposite forces to the main valve core, helping to balance pressure on both sides of the valve core and reduce impact during valve core movement. By directly utilizing fluid pressure to control the valve core, rather than relying on complex electronic or electrical control circuits, the present invention simplifies control system design, reduces commissioning and maintenance costs, and mitigates potential safety hazards associated with electrical components. Liquid entering the return control port exerts pressure through the return valve core, which, combined with the displacement of the main valve core, achieves stepless and smooth flow regulation. The fast-responding return valve core and the main valve core work together to enable the hydraulic system to quickly adapt to changing operating conditions, ensuring the stability and responsiveness of the hydraulic support under various load conditions and improving 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, a brief introduction is given below to 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 any creative work.

[0017] Figure 1 This 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:

[0022] 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 switching valve; 9. Second high-speed switching valve; 10. Third high-speed switching valve; 11. Fourth high-speed switching 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

[0023] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0024] 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 orientations or positional relationships based on the orientations 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, and do not indicate or imply 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 limiting 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.

[0025] The following combination Figure 1 and Figure 2 A specific embodiment of the high water-based proportional valve of the present invention is described.

[0026] The application provides a high water-based proportion valve, which comprises a valve body 1, a cavity is formed in the valve body 1 and penetrates through the valve body 1, 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 1.4, and the rear end part of the cavity is used for arranging 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 port 1.2, a right control port 1.3, a working port 1.6 and a left control port 1.5 are formed in the side surface of the valve body 1 and communicate with the rear end part of the cavity. The front end of the main valve sleeve 2 is sleeved with the front section of the main valve core 4, 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 port 1.2, the right control port 1.3, the working port 1.6 and the left control port 1.5. Liquid entering from the left control port 1.5 and the right control port 1.3 respectively applies rightward and leftward force to the main valve core 4 through the corresponding through holes formed in the main valve sleeve 2. Liquid entering from the liquid return control port 1.1 applies rightward force to the liquid return valve core 5 through the corresponding through hole formed in the main valve sleeve 2 and the through hole in the liquid return valve sleeve 3.

[0027] Specifically, the high water-based proportion valve of the application aims to overcome the problems of unstable control, large valve core displacement pulsation and the like of the high water-based proportion valve in the prior art, realizes stepless smooth adjustment of the flow of a hydraulic system, and improves the posture control precision of a hydraulic support and the safety and reliability of a hydraulic system in dangerous occasions such as coal mines. The cavity in the valve body 1 is divided into two parts of front end and rear end, the front end is used as a liquid return port 1.4 (T port), and the rear end contains the liquid return valve core 5, the main spring 6, the main valve core 4, the liquid return valve sleeve 3 and the main valve sleeve 2, forming an integrated control unit. The valve body 1 is provided with a liquid return 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) on the side surface. These interfaces are communicated with the internal cavity through the through holes in the main valve sleeve 2, so that the liquid can apply pressure or guide backflow at different positions, thereby realizing accurate control of the valve core. The main valve core 4 has a hollow structure and is provided with three sections of front, middle and rear, which not only reduces the weight and volume of the valve core, but also improves the control stability of the proportion 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 accommodation 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 in the main valve sleeve 2 and the liquid return valve sleeve 3, the liquid will apply rightward force to the liquid return valve core 5, affect the opening and closing state of the liquid return valve core 5, and then control the liquid return path.

[0028] 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 provided 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 interior of 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. The working port 1.6 and the liquid inlet 1.2 are respectively connected to the receiving chamber through corresponding through holes provided on the main valve sleeve 2. A through hole for communicating with the receiving chamber is provided 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 return valve core 5, combined with the combined action of the main spring 6, enables the high-water-base proportional valve of the present invention to achieve precise control of liquid flow, reduce valve core displacement pulsation, and improve control smoothness and response speed. Furthermore, the hollow structure design helps reduce the weight of the valve core, reducing energy consumption and improving the overall efficiency and reliability of the proportional valve.

[0029] Specifically, the front section of the main valve core 4 is designed as a cylindrical hollow structure, the hollow portion of which houses the main spring 6. This facilitates efficient spring placement within a limited space while maintaining the structural strength and lightweight nature of the main valve core 4. The middle and rear sections of the main valve core 4 have smaller diameters than the front section, and the middle section is also hollow. The rear section is sheathed with a liquid return valve sleeve 3, which ensures smooth relative movement between the main valve core 4 and the liquid return valve sleeve 3. The hollow design of the middle section facilitates liquid flow. The space formed by the main valve sleeve 2, the middle section of the main valve core 4, and the liquid return valve sleeve 3 is called the accommodating chamber, which serves as the critical path for liquid flow. Through-holes in the sidewalls of the middle section of the main valve core 4 and through-holes in the main valve sleeve 2 connect the working port 1.6 (port A) and the liquid inlet 1.2 (port P) to the accommodating chamber. The liquid return valve core 5 slides over the main valve core 4 and is located within 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.

[0030] According to a high-water-based proportional valve of the present invention, the return valve sleeve 3 has an inner stepped structure and forms a limiting cavity with the rear section of the main valve core 4 near the middle section to achieve positioning of the return valve core 5 on the main valve core 4. The function of the limiting cavity is to limit the lateral and longitudinal movement of the return valve core 5 to ensure that it can accurately move to the predetermined position when subjected to fluid pressure without excessive deviation or vibration. Among them, the inner stepped steps on the inner surface of the return valve sleeve 3 can form a mechanical limit. When the return valve sleeve 3 is installed on the main valve core 4, its inner stepped steps are tightly fitted with the rear section of the main valve core 4 near the middle section, and the space between the two constitutes a limiting cavity to match the size and range of motion of the return valve core 5.

[0031] The following combination 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 refer to each other.

[0032] The present invention also provides a control system for a high-water-base proportional valve based on the above-mentioned embodiment, comprising a pressure source, a liquid return control valve 7, a first high-speed on / off valve 8, a second high-speed on / off valve 9, a third high-speed on / off valve 10, a fourth high-speed on / off valve 11, an electronic control unit, and the high-water-base proportional valve. The electronic control unit is connected to and controls the liquid return control valve 7, the first high-speed on / off valve 8, the second high-speed on / off valve 9, the third high-speed on / off valve 10, and the fourth high-speed on / off valve 11, respectively. The liquid inlet 1.2, left control port 1.5, right control port 1.3, and liquid return control port 1.1 of the high-water-base proportional valve are all connected to the pressure source. The liquid return control valve 7 is disposed between the liquid return control port 1.1 of the high-water-base proportional valve and the pressure source. 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 on / off valve 8 and the second high-speed on / off valve 9. The right control port 1 . 3 of the high-water-based proportional valve is controlled by the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11 .

[0033] The pressure source provides the pressurized liquid required by the system and is typically a pump or other form of liquid pressure supply device. The return liquid control valve 7 is used to control the pressure at the return liquid control port 1.1 (port K3), affecting the opening and closing of the return liquid valve core 5, thereby controlling the return liquid path. The high-speed switching valve is used to quickly switch the pressure between the left control port 1.5 (port K1) and the right control port 1.3 (port K2), thereby precisely controlling the left and right movement of the main valve core 4 and achieving 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 switching valves to achieve dynamic control of the high-water-base proportional valve.

[0034] The inlet 1.2 (P port), the left control port 1.5 (K1 port), the right control port 1.3 (K2 port) and the return control port 1.1 (K3 port) of the high water-based proportional valve are connected with the pressure source, so that sufficient pressure is supplied. Through the return control valve 7, the electronic control unit can accurately adjust the pressure of the return control port 1.1, thereby affecting the movement of the return valve core 5 and controlling the opening and closing of the return path. The left control port 1.5 is controlled through the first high-speed on-off valve 8 and the second high-speed on-off valve 9, and the right control port 1.3 is controlled through the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11. By rapidly switching the states of these high-speed on-off 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 smooth adjustment of the flow.

[0035] According to the control system of the high water-based proportional valve, the electronic control unit preferably comprises a signal inputter 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 signaler 16, a second PWM signaler 18, a third PWM signaler 21 and a fourth PWM signaler 23. The signal inputter 12 is used to send an input signal to the LVDT sensor 13 or the return control valve 7.

[0036] Specifically, the LVDT sensor 13 or the return control valve 7 is started after receiving the signal of the signal inputter 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 on-off valve 8, the second high-speed on-off valve 9, the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11 respectively. Among them, the error signal of the first branch passes through the first PD controller 14 to the first judgment function module 15, and then the first judgment function module 15 outputs the duty ratio to the first PWM signaler 16, so as to control the first high-speed on-off valve 8. The error signal of the second branch enters the first P controller 17 after being inverted, and the first P controller 17 adjusts the duty ratio of the second high-speed on-off valve 9 by controlling the second PWM signaler 18. The error signal of the third branch enters the second PD controller 19 to the second judgment function module 20 after being inverted, and then the second judgment function module 20 outputs the duty ratio to the third PWM signaler 21, so as to control the third high-speed on-off 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 ratio of the fourth high-speed on-off valve 11 by controlling the fourth PWM signaler 23.

[0037] The following will be described in combination with Figure 1 , Figure 2 , Figure 3 and Figure 4The non-pulsation control method provided by the present application is described below, which can be referred to in combination with the high-water-based proportional valve and the control system of the high-water-based proportional valve described above. In the description of the present application, the side where the valve body 1 return port 1.4 is located is the right side, and the side away from the return port 1.4 is the left side.

[0038] The present application also provides a non-pulsation control method for the control system of the high-water-based proportional valve according to the above embodiments. The method uses the real-time feedback of the LVDT sensor 13 to dynamically adjust the control pressure on both sides of the valve through a precise PID control algorithm (PD and P controllers are mentioned in particular), to ensure smooth and continuous flow of fluid inside the valve, and to avoid pulsation or vibration caused by sudden pressure changes.

[0039] The non-pulsation control method specifically includes the following steps: inputting a signal r through the signal inputter 12; when the signal inputter 12 inputs a signal r of 0, the return control valve 7 is energized, the return control port 1.1 is connected to the return flow path, and the return valve core 5 is pushed to the leftmost end under the pressure of the working port 1.6, at which time the return port 1.4 is connected to the working port 1.6, and the high-water-based proportional valve is in an AT working state; when the signal inputter 12 inputs a signal r that is not 0, the return control valve 7 is de-energized, 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 through the control system of the high-water-based proportional valve.

[0040] Specifically, when the signal inputter 12 does not receive any input signal (i.e., the signal r is 0), the system is in a default ready state. At this time, the return control valve 7 is energized. The return flow path is connected to the return control port 1.1, allowing liquid to flow. The return valve core 5 is pushed to the leftmost end under the pressure of the working port 1.6, ensuring that the return port 1.4 is connected to the working port 1.6. The high-water-based proportional valve is in an AT working state, allowing fluid to flow from the working port 1.6 to the return port 1.4, maintaining a preset circulation state.

[0041] When the signal inputter 12 receives a non-zero signal r, the system needs to be controlled. At this time, the return control valve 7 is de-energized. The LVDT sensor 13 is energized and starts to work, 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, and 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 PD controller and P controller mechanisms to achieve the desired fluid control effect.

[0042] According to the pulseless control method of the application, the pressure of the left control port 1.5 (K1 port) and the right control port 1.3 (K2 port) is accurately 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, ensuring the smooth operation of the entire hydraulic system. In the 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, the valve core displacement error e is calculated; when the valve core displacement error e is greater than 0, the pressure of the left control port 1.5 is increased and the pressure of the right control port 1.3 is decreased by the control system of the high water-based proportional valve, thereby realizing the right 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 decreased and the pressure of the right control port 1.3 is increased by the control system of the high water-based proportional valve, thereby realizing the left movement of the main valve core 4; when the valve core displacement error e is equal to 0, the right control port 1.3 forms a dead space by the control system of the high water-based proportional valve, so that the main valve core 4 is locked.

[0043] 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 and the desired position of the main valve core 4.

[0044] When the valve core displacement error e is greater than 0, it indicates that the position of the main valve core 4 is more left than expected and needs to move right to reach the target position. By increasing the pressure of the left control port 1.5 (K1 port) and decreasing the pressure of the right control port 1.3 (K2 port), the main valve core 4 is prompted to move right until the error is reduced to zero.

[0045] When the valve core displacement error e is less than 0, the position of the main valve core 4 is more right than expected and needs to move left. The control system decreases 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 prompt the main valve core 4 to move left to reduce the error to zero.

[0046] 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 move further. The control system controls the right control port 1.3 (K2 port) to form a "dead space" state, i.e. maintaining a certain pressure but no longer having flow changes, effectively locking the position of the main valve core 4 to prevent it from moving due to slight pressure fluctuations in the system, ensuring the stability and control accuracy of the system.

[0047] Through the above accurate pressure adjustment, the control method can effectively eliminate or greatly reduce the pulsation phenomenon of the main valve core 4 during movement, ensuring the smooth operation of the hydraulic system and improving the accuracy and response speed of flow control.

[0048] According to the pulseless control method of the application, the pressure of the left control port 1.5 is increased and the pressure of the right control port 1.3 is decreased by the control system of the high water-based proportional valve, so that the main valve core 4 moves to the right in the following steps: the first error signal is input into the first PD controller 14 and then into the first judgment function module 15, and the duty cycle is output to the first PWM signaler 16 to control the first high-speed on-off valve 8 to increase the duty cycle; the second error signal is inverted and then input into the first P controller 17, and the duty cycle of the second high-speed on-off valve 9 is decreased by the second PWM signaler 18; the third error signal is input into the second judgment function module 20, so that the duty cycle of the third high-speed on-off valve 10 is 0 and the third high-speed on-off valve 10 is kept closed; and the fourth error signal is input into the second P controller 22, so that the duty cycle of the fourth high-speed on-off valve 11 is increased.

[0049] 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 is input into the first PD controller 14 and then into the first judgment function module 15, and the duty cycle is output to the first PWM signaler 16 to control the first high-speed on-off valve 8 to increase the duty cycle. Meanwhile, the second error signal is inverted and then input into the first P controller 17, and the duty cycle of the second high-speed on-off valve 9 is decreased by the second control PWM signaler. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the left control port 1.5 is increased. The third error signal is input into the second judgment function module 20, so that the duty cycle of the third high-speed on-off valve 10 is 0 and the third high-speed on-off valve 10 is kept closed. The fourth error signal is input into the second P controller 22, so that the duty cycle of the fourth high-speed on-off valve 11 is increased. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the right control port 1.3 is decreased to the pressure of the liquid return port 1.4; under the joint action of the pressure increase of the left control port 1.5 and the pressure decrease of the right control port 1.3, the main valve core 4 moves to the right, and the greater the valve core displacement error e is, the faster the moving speed is.

[0050] According to the pulseless control method of the application, the pressure of the left control port 1.5 is increased and the pressure of the right control port 1.3 is decreased by the control system of the high water-based proportional valve, so that the main valve core 4 moves to the right in the following steps: the first error signal is input into the first PD controller 14 and then into the first judgment function module 15, and the duty cycle is output to the first PWM signaler 16 to control the first high-speed on-off valve 8 to increase the duty cycle; the second error signal is inverted and then input into the first P controller 17, and the duty cycle of the second high-speed on-off valve 9 is decreased by the second PWM signaler 18; the third error signal is input into the second judgment function module 20, so that the duty cycle of the third high-speed on-off valve 10 is 0 and the third high-speed on-off valve 10 is kept closed; and the fourth error signal is input into the second P controller 22, so that the duty cycle of the fourth high-speed on-off valve 11 is increased.

[0051] Specifically, when the valve core displacement error e is less than 0, the main valve core 4 needs to move left. The first error signal passes through the first judgment function module 15, so that the duty ratio of the first high-speed on-off valve 8 is 0 and remains closed. The second error signal passes through the inverter and enters the first P controller 17, so that the duty ratio of the second high-speed on-off valve 9 increases. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the left control port 1.5 decreases to the pressure of the back liquid port 1.4. The third error signal passes through the inverter and enters the second PD controller 19, and then the duty ratio is output to the third PWM signaler 21, controlling the duty ratio of the third high-speed on-off valve 10 to increase. The fourth error signal directly enters the second P controller 22, and through the control of the fourth PWM signaler 23, the duty ratio of the fourth high-speed on-off valve 11 decreases. Under the joint action of the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11, the pressure of the right control port 1.3 increases; under the joint action of the pressure decrease of the left control port 1.5 and the pressure increase of the right control port 1.3, the main valve core 4 moves left and the greater the valve core displacement error e, the faster the moving speed.

[0052] According to the non-pulsation control method of the application, in the step of controlling the right control port 1.3 to form a dead space by the high water-based proportional valve control system, so that the main valve core 4 is locked, the second, third and fourth output PWM signals are all 0, so that the second, third and fourth high-speed on-off valves 9, 10 and 11 are all closed; the right control port 1.3 forms a dead space, 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] Specifically, when the valve core displacement error e is equal to 0, the second, third and fourth output PWM signals are all 0, so that the second, third and fourth high-speed on-off valves 9, 10 and 11 are all closed; the right control port 1.3 forms a dead space, 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.

[0054] The high-speed on-off valve pilot control method for locking the valve core by using the volume dead space overcomes the flow pulsation problem existing in the existing high-speed on-off valve pilot control, and realizes the stable flow output of the proportional valve pilot control under the premise of retaining the advantages of simple structure, low power consumption and fast response of the high-speed on-off valve pilot control.

[0055] According to the preferred embodiment of the application, the high water-based proportional valve, its control system and non-pulsation control method are combined, and the operation principle is as follows:

[0056] The main valve core 4 is screwed with the return liquid valve sleeve 3 to form a hydraulic balance type 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 return liquid valve sleeve 3, and the liquid pressure is counteracted due to the same area. 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, and the movement of the combination of the main valve core 4 and the return liquid valve sleeve 3 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.

[0057] When the combination of the main valve core 4 and the return liquid valve sleeve 3 is insufficiently pressed by the left control port 1.5 or is greatly pressed by the right control port 1.3, the liquid inlet port 1.2 is blocked. At this time, the return liquid control valve 7 is powered on, the return liquid control port 1.1 is communicated with the return liquid, and the return liquid valve core 5 is pushed to the leftmost end under the pressure of the working port 1.6. At this time, the return liquid port 1.4 is communicated with the working port 1.6, and the proportional valve is in the AT working state.

[0058] When the combination of the main valve core 4 and the return liquid valve sleeve 3 is greatly pressed by the left control port 1.5 or is insufficiently pressed by the right control port 1.3, the main valve core 4 moves to the right, the liquid inlet port 1.2 is communicated with the working port 1.6, the PA main valve port is opened, different valve port areas correspond to different flow rates, and finally the pressure of the control port can be controlled to control the flow rate of the main valve. At this time, the return liquid control valve 7 is powered off, the return liquid control port 1.1 is communicated with the pressure source, the return liquid valve core 5 is pushed to the rightmost end. At this time, the return liquid port 1.4 is not communicated with the working port 1.6, and the proportional valve is in the PA working state.

[0059] The pressure of the left control port 1.5 is composed of a half-bridge control of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, and the pressure of the right control port 1.3 is composed of a half-bridge control of the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11, and the control method is as shown in Figure 4 When the given valve core displacement signal is given, when the given signal r is 0, the return liquid control valve 7 is powered on, so that the proportional valve is in the AT working state. When the given signal r is not 0, the return liquid control valve 7 is powered off. At the same time, the valve core displacement error e is obtained by negative feedback operation with the LVDT sensor 13. The displacement error e is divided into four signals for operation.

[0060] When the spool displacement error e is greater than 0, it indicates that the main valve spool 4 needs to move right. 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 signaler 16 to control the duty cycle of the first high-speed on-off valve 8 to increase. At the same time, the second error signal enters the first P controller 17 after being inverted, and through the control of the second PWM signaler 18, the duty cycle of the second high-speed on-off valve 9 is reduced. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the left control port 1.5 rises rapidly. The third error signal passes through the second judgment function module 20, so that the duty cycle of the third high-speed on-off valve 10 is 0 and remains closed. The fourth error signal passes through the second P controller 22, so that the duty cycle of the fourth high-speed on-off valve 11 increases. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the right control port 1.3 drops to the pressure of the return port 1.4. Under the joint action of the rapid rise of the pressure of the left control port 1.5 and the drop of the pressure of the right control port 1.3, the main valve spool 4 moves right. And the greater the spool displacement error e, the faster the movement speed.

[0061] When the spool displacement error e is less than 0, it indicates that the main valve spool 4 needs to move left. The first error signal passes through the first judgment function module 15, so that the duty cycle of the first high-speed on-off valve 8 is 0 and remains closed. The second error signal enters the first P controller 17 after being inverted, so that the duty cycle of the second high-speed on-off valve 9 increases. Under the joint action of the first high-speed on-off valve 8 and the second high-speed on-off valve 9, the pressure of the left control port 1.5 drops to the pressure of the return port 1.4. The third error signal passes through the second PD controller 19 and enters the second judgment function module 20, and then outputs the duty cycle to the third PWM signaler 21 to control the duty cycle of the third high-speed on-off valve 10 to increase. The fourth error signal directly enters the second P controller 22, and through the control of the fourth PWM signaler 23, the duty cycle of the fourth high-speed on-off valve 11 is reduced. Under the joint action of the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11, the pressure of the right control port 1.3 rises rapidly. Under the joint action of the rapid drop of the pressure of the left control port 1.5 and the rapid rise of the pressure of the right control port 1.3, the main valve spool 4 moves left. And the greater the spool displacement error e, the faster the movement speed.

[0062] When the spool displacement error e is equal to 0, the PWM signals output by the second, third and fourth paths are all 0, so that the second high-speed on-off valve 9, the third high-speed on-off valve 10 and the fourth high-speed on-off valve 11 are all closed. This makes the right control port 1.3 form a dead space, and the main valve spool 4 is locked and cannot move, so that the main valve spool 4 stops without fluctuation after reaching the target position.

[0063] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "aspects", "specific aspects", or "some aspects" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or aspect are included in at least one embodiment or aspect of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or aspect. Also, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in one or more embodiments or aspects. In addition, those skilled in the art can combine and combine the different embodiments or aspects described in the specification and the features of the different embodiments or aspects without contradiction, and the combination.

[0064] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit it; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

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 serving as a liquid return port (1.4), and the rear end portion of the cavity being used to dispose 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 of the valve body (1) is provided with 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 communicated with the rear end portion of the cavity; 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 return liquid valve sleeve (3); the main valve sleeve (2) is provided with through holes corresponding to the return liquid 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) 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 return liquid control port (1.1) applies rightward force to the return liquid valve core (5) after passing through the corresponding through holes provided on the main valve sleeve (2) and the through holes on the return liquid valve sleeve (3); 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 middle section of the main valve core (4) is hollow inside; the rear section of the main valve core (4) is sleeved with the 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 opening or closing of the through hole on the side wall of the middle section of the main valve core (4) is controlled by sliding the liquid return valve core (5) left and right.

2. The high water-based proportional valve according to claim 1, characterized in that: 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).

3. The high water-based proportional valve according to claim 1, characterized in that: The liquid return valve sleeve (3) has an inner stepped structure and forms a limiting cavity with the rear section of the main valve core (4) near the middle section to achieve 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 on-off valve (8), a second high-speed on-off valve (9), a third high-speed on-off valve (10), a fourth high-speed on-off 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-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); and 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).

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, 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 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 control system of the high water-based proportional valve controls the pressure of the left control port (1.5) to increase and the pressure of the right control port (1.3) to decrease, 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) by 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 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 duty cycle of the first high-speed switching 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 switching valve (10) is 0 and remains in a closed state; The fourth error signal passes through the second P controller (22), causing the duty cycle of the fourth high-speed switching valve (11) to increase.

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 switching valve (8) is 0 and remains in a closed state; The second error signal is inverted and enters the first P controller (17), thereby increasing the duty cycle of the second high-speed switching valve (9); The third error signal is inverted and then enters the second judgment function module (20) through 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 switching valve (10) to increase; The fourth error signal enters the second P controller (22), and controls the fourth PWM signal device (23) so as to reduce the duty cycle of the fourth high-speed switching valve (11).

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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