Design method of high-flow three-stage electro-hydraulic servo valve system

Abstract

The invention relates to a design method of a large-flow three-stage electro-hydraulic servo valve system. The invention relates to the technical field of hydraulic electronic control, the system comprises a pilot valve, an electronic reversing valve and a main valve, the pilot valve adopts a two-stage valve, the pilot valve is driven to output flow through a control instruction adjusted by a controller to control the displacement of a valve element of the main valve, and the displacement of the valve element is transmitted to the controller through a displacement sensor to be controlled and modulated; the electronic reversing valve is electrified, the reversing valve moves to the left position, and the output of the pilot valve normally controls the main valve; when the servo valve breaks down or does not work, the electronic reversing valve is powered off, and the reversing valve moves to the right position, so that the left cavity and the right cavity of the main valve are communicated, an actuator of the servo system does not output external force, and the automatic protection effect of the system is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of hydraulic electronic control, and is a design method for a large-flow three-stage electro-hydraulic servo valve system. Background Art

[0002] The concept of servo valves originally originated from the need for precise control of fluid power systems. In the early 20th century, with the initial development of hydraulic technology, people began to try to use electrical signals to control hydraulic components. Early servo valves had simple structures and limited performance, mainly based on simple electromagnetic principles to achieve preliminary control of hydraulic oil flow and pressure.

[0003] The research focus at that time was on how to establish the basic mechanism of electro-hydraulic signal conversion and how to improve the basic control accuracy of valves. Most of the servo valves at this stage were single-stage structures with low control accuracy and response speed, but they laid the theoretical and practical foundation for the subsequent development of more complex multi-stage servo valves.

[0004] After the middle of the 20th century, researchers began to design three-stage servo valves. Three-stage servo valves add one level of auxiliary control on the basis of two-stage servo valves, and their structural design is more complicated. At this stage, the main challenge is how to reasonably design the coordinated control mechanism between the three levels so that each valve level can cooperate effectively to achieve higher control accuracy and more stable performance.

[0005] The early three-stage servo valve was initially tested in the aerospace field and used in high-performance flight control systems of aircraft to meet the aircraft's demand for precise control of the control surfaces during high-maneuver flight. The performance of the three-stage servo valve has gradually improved through continuous optimization of the structure and control algorithm.

[0006] After years of research and improvement, the technology of three-stage servo valve gradually matured from the end of the 20th century to the beginning of the 21st century. Its performance indicators such as control accuracy, response speed, flow output range, etc. have been greatly improved. Supported by the progress of materials science, the valve body and valve core of the three-stage servo valve can use higher performance alloy materials, which improves the wear resistance, corrosion resistance and working reliability of the valve.

[0007] This makes the three-stage servo valve widely used in many fields, including ships, metallurgy, engineering machinery, industrial automation, etc. In the era of Industry 4.0, with the development of intelligent manufacturing, the three-stage servo valve, as a high-precision hydraulic control element, has become one of the key equipment for realizing precise control of automated production lines, and is constantly developing in the direction of intelligence and integration.

[0008] As the core control element in the hydraulic servo system, the three-stage servo valve has been widely used in many industries such as metallurgy, mining, and shipbuilding, especially the large-flow three-stage servo valve. The existing three-stage servo valve mainly relies on the purchase of finished products from abroad.

[0009] However, currently, large-flow three-stage servo valves are mainly imported, and there are few domestic research and development units. Even if a small number of products are launched, the performance is poor. Therefore, in the hydraulic servo system, the performance of domestic self-developed products cannot meet the required technical indicators, especially the stability is poor, and the procurement cost of foreign three-stage servo valves is high. It is imperative to develop independent high-performance three-stage servo valves. Summary of the invention

[0010] In view of the shortcomings of the prior art, the present invention provides a design method for a large-flow three-stage electro-hydraulic servo valve system. The present invention is mainly intended to meet the application needs in the field of large-flow and high-frequency response servo.

[0011] The present invention provides the following technical solutions:

[0012] A large flow three-stage electro-hydraulic servo valve system, the system comprises: a pilot valve, an electronic reversing valve and a main valve. The pilot valve adopts a two-stage valve. The control instruction adjusted by the controller drives the pilot valve to output flow to control the displacement of the valve core of the main valve. The displacement of the valve core is transmitted to the controller through a displacement sensor for control modulation.

[0013] When the electronic reversing valve is energized, the reversing valve moves to the left position, and the output of the pilot valve controls the main valve normally; when the servo valve itself fails or does not work, the electronic reversing valve is powered off and the reversing valve moves to the right position, thereby connecting the left and right chambers of the main valve, and the servo system actuator does not output external force, thereby playing a role in system autonomous protection.

[0014] A design method for a large-flow three-stage electro-hydraulic servo valve system is disclosed. The method is based on a large-flow three-stage electro-hydraulic servo valve system. The servo valve is controlled by different algorithms to be suitable for different application occasions. The servo valve controller is divided into two parts for design. One part is the algorithm controller part, which is realized by a digital controller; the other part is the power amplifier acquisition part, which is realized by an analog circuit.

[0015] Preferably, the displacement conditioning circuit converts the valve core displacement of the main valve into a voltage or current signal output, including conversion and zeroing; conversion is to calibrate the valve core displacement to a voltage or current signal output of a corresponding range, and zeroing is to configure the valve core at a certain position as an electrical zero point.

[0016] Preferably, the speed conditioning circuit is designed with a speed feedback closed-loop circuit to ensure smooth movement of the main valve core, stable speed and increase the natural frequency of the valve, and also has a filtering function.

[0017] Preferably, the drive conditioning circuit adjusts the regulating signal, the speed feedback signal and the signal for correcting the zero bias of the servo valve input by the control algorithm, and at the same time, the circuit modifies the polarity of the servo valve according to different usage scenarios.

[0018] Preferably, it also includes a digital control part:

[0019] Digital Controller:

[0020] Three-stage servo valve characteristic function:

[0021]

[0022] Among them, K v is the flow gain of the valve, ω m is the natural frequency, ζ m is the damping ratio.

[0023] Preferably, it also includes

[0024] PD controller:

[0025]

[0026] Among them, K p , T d are proportional gain and differential gain, ω c This is to take into account the turning frequency of the inertia link that can be increased by the physical realization of the differential link. This control is mainly used to increase the bandwidth of the valve and determines the stability of the valve control.

[0027] Preferably, it also includes:

[0028] Pole configuration controller, analysis of G1(s), G2(s), the lowest turning frequency of the three-stage valve affecting the system characteristics is ω m , which corresponds to the oscillation link;

[0029] The pole placement method is used to cancel the pole and expand the bandwidth of the system without affecting the stability. The corresponding pole placement controller is:

[0030]

[0031] When ω in G(s) nc =ω m , nc =ζ m When , the controller offsets the pole in the three-stage valve that is farthest from the imaginary axis.

[0032] A computer-readable storage medium stores a computer program, which is executed by a processor to implement a design method for a large-flow three-stage electro-hydraulic servo valve system.

[0033] A computer device comprises a memory and a processor, wherein the memory stores a computer program and the processor implements a method for designing a large-flow three-stage electro-hydraulic servo valve system when executing the computer program.

[0034] The present invention has the following beneficial effects:

[0035] Compared with the prior art, the present invention has the following advantages:

[0036] The system and method of the present invention solve the problem of poor performance of the current domestic three-stage valve, while increasing the autonomous protection function and reducing the purchase cost of the three-stage valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 Shown is a schematic diagram of the modified three-stage servo valve of the present invention;

[0039] Figure 2 Shown is a basic structural diagram of a modified three-stage servo valve of the present invention;

[0040] Figure 3 Shown is a schematic diagram of a modified three-stage servo valve controller of the present invention;

[0041] Figure 4 Shown is the valve core displacement circuit diagram of the present invention;

[0042] Figure 5 Shown is the speed circuit diagram of the present invention;

[0043] Figure 6 Shown is a driving circuit diagram of the present invention;

[0044] Figure 7 Shown is the frequency response diagram of the three-stage servo valve of the present invention.

[0045] In the figure, 1-pilot valve, 2-electronic reversing valve, 3-main valve. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting 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.

[0048] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] The present invention is described in detail below in conjunction with specific embodiments. Specific embodiment one:

[0052] according to Figures 1 to 7 As shown, the specific optimization technical solution adopted by the present invention to solve the above technical problems is: the present invention relates to a design method for a large-flow three-stage electro-hydraulic servo valve system.

[0053] A large flow three-stage electro-hydraulic servo valve system, the system comprising: a pilot valve 1, an electronic reversing valve 2 and a main valve 3, the pilot valve 1 adopts a two-stage valve, and the control instruction adjusted by the controller drives the pilot valve to output flow to control the displacement of the valve core of the main valve 3, and the displacement of the valve core is transmitted to the controller through a displacement sensor for control modulation;

[0054] When the electronic reversing valve 2 is energized, the reversing valve moves to the left position, and the output of the pilot valve controls the main valve normally; when the servo valve itself fails or does not work, the electronic reversing valve 2 is de-energized and the reversing valve moves to the right position, thereby connecting the left and right chambers of the main valve 3, and the servo system actuator does not output external force, thereby playing a role in system autonomous protection. Specific embodiment 2:

[0056] The difference between the second embodiment of the present application and the first embodiment is that:

[0057] The present invention provides a design method for a large-flow three-stage electro-hydraulic servo valve system. The method is based on a large-flow three-stage electro-hydraulic servo valve system. The servo valve is controlled by different algorithms to be suitable for different application occasions. The servo valve controller is divided into two parts for design. One part is the algorithm controller part, which is realized by a digital controller; the other part is the power amplifier acquisition part, which is realized by an analog circuit. Specific embodiment three:

[0059] The difference between the third embodiment of the present application and the second embodiment is that:

[0060] The displacement conditioning circuit converts the valve core displacement of the main valve into a voltage or current signal output, including conversion and zeroing; conversion is to calibrate the valve core displacement into a voltage or current signal output of the corresponding range, and zeroing is to configure the valve core at a certain position as an electrical zero point. Specific embodiment four:

[0062] The difference between the fourth embodiment of the present application and the third embodiment is that:

[0063] Speed ​​conditioning circuit, in order to ensure the smooth movement of the main valve core, stable speed and increase the natural frequency of the valve, a speed feedback closed-loop circuit is designed, which also has a filtering function. Specific embodiment five:

[0065] The difference between the fifth embodiment of the present invention and the fourth embodiment is that:

[0066] The drive conditioning circuit adjusts the adjustment signal, speed feedback signal and signal for correcting the zero bias of the servo valve input by the control algorithm. At the same time, the circuit modifies the polarity of the servo valve according to different usage scenarios. Specific embodiment six:

[0068] The difference between the sixth embodiment of the present invention and the fifth embodiment is that:

[0069] Also includes digital control part:

[0070] Digital Controller:

[0071] Three-stage servo valve characteristic function:

[0072]

[0073] Among them, K v is the flow gain of the valve, ω m is the natural frequency, ζ m is the damping ratio. Specific embodiment seven:

[0075] The difference between the seventh embodiment of the present invention and the sixth embodiment is that:

[0076] PD controller:

[0077]

[0078] Among them, K p , T d are proportional gain and differential gain, ω c This is to take into account the turning frequency of the inertia link that can be increased by the physical realization of the differential link. This control is mainly used to increase the bandwidth of the valve and determines the stability of the valve control. Specific embodiment eight:

[0080] The difference between the eighth embodiment of the present invention and the seventh embodiment is that:

[0081] Pole configuration controller, analysis of G1(s), G2(s), the lowest turning frequency of the three-stage valve affecting the system characteristics is ω m , which corresponds to the oscillation link;

[0082] The pole placement method is used to cancel the pole and expand the bandwidth of the system without affecting the stability. The corresponding pole placement controller is:

[0083]

[0084] When ω in G(s) nc =ω m , nc =ζ m When , the controller offsets the pole in the three-stage valve that is farthest from the imaginary axis. Specific embodiment nine:

[0086] The difference between the ninth embodiment of the present invention and the eighth embodiment is that:

[0087] The present invention provides a computer-readable storage medium on which a computer program is stored. The program is executed by a processor to implement a design method for a large-flow three-stage electro-hydraulic servo valve system. Specific embodiment ten:

[0089] The difference between the tenth embodiment of the present invention and the ninth embodiment is that:

[0090] The present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements a method for designing a large-flow three-stage electro-hydraulic servo valve system when executing the computer program. Specific embodiment eleven:

[0092] The difference between the eleventh embodiment of the present invention and the tenth embodiment is that:

[0093] like Figure 1 As shown in the figure, the valve body itself consists of two parts: the pilot valve and the main valve. The pilot valve is composed of the existing secondary valve. Through the control instructions adjusted by the controller, the pilot valve output flow is driven to control the displacement of the valve core of the third stage-the main valve, and the displacement of the valve core is transmitted to the controller through the displacement sensor for control modulation.

[0094] The detailed schematic diagram of the modified three-stage servo valve is as follows: Figure 2 As shown. In the figure, 1 is the secondary pilot valve, 2 is the newly added electronic reversing valve of this patent, and 3 is the third-stage valve body added by this patent. During normal operation, the electronic reversing valve 2 is energized, the reversing valve moves to the left position, and the output of the pilot valve normally controls the third-stage valve body; if the servo valve itself fails or does not work, the electronic reversing valve 2 is powered off, and the reversing valve moves to the right position, so that the left and right chambers of the third-stage valve body are connected, which will prevent the servo system actuator using the three-stage valve from outputting external force, thereby playing a role in system autonomous protection.

[0095] Controller composition

[0096] In order to control the servo valve through different algorithms to suit different applications, the servo valve controller is divided into two parts. One part is the algorithm controller part, which is realized by a digital controller; the other part is the power amplifier acquisition part, which is realized by an analog circuit. Figure 3 shown.

[0097] Hardware power amplifier acquisition circuit

[0098] 1) Displacement conditioning circuit

[0099] like Figure 4 As shown. The function of this part is to convert the valve core displacement of the third-stage valve into a voltage or current signal output. The specific functions include conversion and zeroing. Conversion is to calibrate the valve core displacement into a voltage or current signal output of the corresponding range. Zeroing is to configure the valve core at a certain position as an electrical zero point.

[0100] 2) Speed ​​conditioning circuit

[0101] like Figure 5 In order to ensure the smooth movement and speed stability of the third-stage valve core and to increase the natural frequency of the valve, a speed feedback closed-loop circuit is designed, which also has a filtering function.

[0102] 3) Drive conditioning circuit

[0103] like Figure 6 This part mainly adjusts the control algorithm input adjustment signal, speed feedback signal and the signal for correcting the servo valve zero bias. At the same time, in order to adapt to different usage occasions, the circuit can also modify the polarity of the servo valve.

[0104] Digital Controller:

[0105] 1) Three-stage servo valve characteristic function:

[0106]

[0107] It can be seen that the overall performance of the modified three-stage valve is an inertia link and an oscillation link. v is the flow gain of the valve; K v is the speed amplification factor of the valve, which is also the turning frequency of the inertia link in the characteristic; ω m is the natural frequency, which is also the turning frequency of the oscillation link in the valve characteristics; ζ m is the damping ratio.

[0108] 2)PD controller:

[0109] Considering the system debugging needs, the PD controller is designed as follows

[0110]

[0111] In the formula, K p , T d are proportional gain and differential gain, ω c This is to take into account the turning frequency of the inertia link that can be increased by the physical realization of the differential link. This control is mainly used to increase the bandwidth of the valve and determines the stability of the valve control.

[0112] 3) Pole placement controller:

[0113] Analyzing G1(s) and G2(s), the lowest turning frequency of the three-stage valve affecting the system characteristics is ω m , which corresponds to the oscillation link.

[0114] The pole placement method is now used to cancel the pole and further expand the bandwidth of the system without affecting the stability. The corresponding pole placement controller is

[0115]

[0116] When ω in G(s) nc =ω m , nc =ζ mWhen , the controller can just offset the pole in the three-stage valve that is closer to the imaginary axis.

[0117] Calculation example:

[0118] Use this servo valve controller to perform frequency sweep performance test on the valve, such as Figure 7 As shown in the figure, it can be seen that after the controller is adjusted, the bandwidth of the three-level valve is widened, and the phase lag within the entire bandwidth is less.

[0119] In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0120] The above is only a preferred implementation of a method for designing a large flow three-stage electro-hydraulic servo valve system. The protection scope of a method for designing a large flow three-stage electro-hydraulic servo valve system is not limited to the above embodiment. All technical solutions under this idea belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, several improvements and changes without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-flow three-stage electro-hydraulic servo valve system, characterized by: The system comprises: a pilot valve, an electronic reversing valve and a main valve. The pilot valve adopts a two-stage valve. The control instruction adjusted by the controller drives the pilot valve to output flow to control the displacement of the valve core of the main valve. The displacement of the valve core is transmitted to the controller through a displacement sensor for control modulation. When the electronic reversing valve is energized, the reversing valve moves to the left position, and the output of the pilot valve controls the main valve normally; when the servo valve itself fails or does not work, the electronic reversing valve is powered off and the reversing valve moves to the right position, thereby connecting the left and right chambers of the main valve, and the servo system actuator does not output external force, thereby playing a role in system autonomous protection.

2. A method for designing a large flow three-stage electro-hydraulic servo valve system, the method being based on the system of claim 1, characterized in that: The servo valve is controlled by different algorithms for different applications. The servo valve controller is divided into two parts for design. One part is the algorithm controller part, which is realized by a digital controller; the other part is the power amplifier acquisition part, which is realized by an analog circuit.

3. The method according to claim 2, characterized in that: The displacement conditioning circuit converts the valve core displacement of the main valve into a voltage or current signal output, including conversion and zeroing; conversion is to calibrate the valve core displacement into a voltage or current signal output of the corresponding range, and zeroing is to configure the valve core at a certain position as an electrical zero point.

4. The method according to claim 1, characterized in that: Speed ​​conditioning circuit, in order to ensure the smooth movement of the main valve core, stable speed and increase the natural frequency of the valve, a speed feedback closed-loop circuit is designed, which also has a filtering function.

5. The method according to claim 4, characterized in that: The drive conditioning circuit adjusts the adjustment signal, speed feedback signal and signal for correcting the zero bias of the servo valve input by the control algorithm. At the same time, the circuit modifies the polarity of the servo valve according to different usage scenarios.

6. The method according to claim 1, characterized in that: Also includes digital control part: Digital Controller: Three-stage servo valve characteristic function: Among them, K v is the flow gain of the valve, ω m is the natural frequency, ζ m is the damping ratio.

7. The method according to claim 6, characterized in that: Also includes PD controller: Among them, K p , T d are proportional gain and differential gain, ω c This is to take into account the turning frequency of the inertia link that can be increased by the physical realization of the differential link.

8. The method according to claim 7, characterized in that: include: Pole configuration controller, analysis of G1(s), G2(s), the lowest turning frequency of the three-stage valve affecting the system characteristics is ω m , which corresponds to the oscillation link; The pole placement method is used to cancel the pole and expand the bandwidth of the system without affecting the stability. The corresponding pole placement controller is: When ω in G(s) nc =ω m , nc =ζ m When , the controller offsets the pole in the three-stage valve that is farthest from the imaginary axis.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the method according to claims 2-8.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the method of claims 2-8 is implemented.

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