Electro-hydraulic servo valve driving force increasing method and electro-hydraulic servo valve

Abstract

The invention relates to the technical field of electro-hydraulic servo valves, and discloses an electro-hydraulic servo valve driving force increasing method and an electro-hydraulic servo valve. The lifting method comprises the following steps: configuring a benchmarking electro-hydraulic servo valve and a to-be-calibrated electro-hydraulic servo valve; respectively obtaining a benchmarking pressure-current characteristic curve of the benchmarking electro-hydraulic servo valve, a benchmarking pressure-displacement characteristic curve of the prestage, a pressure-current characteristic curve of the electro-hydraulic servo valve to be calibrated and a pressure-displacement characteristic curve of the prestage; under the constant value input current, the benchmarking displacement of the benchmarking electro-hydraulic servo valve deflection plate and the actual displacement of the electro-hydraulic servo valve deflection plate to be calibrated are obtained; calculating the theoretical displacement of a deflection plate of the electro-hydraulic servo valve to be calibrated, correcting the pressure-displacement characteristic curve by applying the deviation between the theoretical displacement and the actual displacement, and finding out the benchmarking displacement of the benchmarking electro-hydraulic servo valve under the constant input current; and constructing a constraint condition, and based on the constraint condition, lifting the theoretical displacement to the benchmarking displacement according to a preset driving force lifting scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of electro-hydraulic servo valves, and in particular to a method for improving the driving force of an electro-hydraulic servo valve and an electro-hydraulic servo valve. Background Art

[0002] Electro-hydraulic servo valves are highly sophisticated components that combine mechanical, electronic, and hydraulic technologies. Due to their exceptional control accuracy, rapid dynamic response, flexible electrical signal processing capabilities, powerful power amplification characteristics, and compact design, they have become the "nerve center" of modern high-performance hydraulic systems. In key applications such as large transport aircraft and civil airliners, their performance directly determines the reliability and safety of various steering gears, control systems, and actuators, and is crucial to flight control.

[0003] However, the actual operating conditions of electro-hydraulic servo valves are often extremely demanding, complex, and highly variable. The precise clearance between the valve core and sleeve (typically measured in micrometers) makes them extremely sensitive to contaminants in the operating environment, such as solid particles, colloids, and moisture in the oil. These contaminants easily accumulate, become embedded, or form sludge within the valve core-sleeve gap, causing significant sticking resistance. Furthermore, extreme temperature fluctuations (such as those at high altitudes, high temperatures near the engine compartment, or self-heating during high-power operation) can cause uneven thermal expansion and contraction of dissimilar materials, such as the valve core, sleeve, and supporting structure, further hindering valve core movement and even leading to complete seizure.

[0004] At present, the industry's main ideas for dealing with the problem of valve core sticking are concentrated in the following aspects: first, improving oil cleanliness, such as adopting a more sophisticated filtration system and strictly controlling the oil pollution level; second, improving materials and surface treatment, such as selecting wear-resistant and corrosion-resistant materials, and applying special surface coatings to reduce friction and pollutant adhesion; third, optimizing structural design, such as improving the geometry of the valve core and valve sleeve, and the design of the pressure equalizing groove to balance the radial force and reduce the hydraulic clamping force; fourth, strengthening maintenance, such as stipulating strict regular flushing, inspection and replacement cycles. However, each of these solutions has limitations. First, absolute contamination control is difficult to guarantee because, under complex operating conditions, the risk persists, and fine particles or soft contaminants may still intrude into precise gaps. Second, the inherent characteristics of temperature deformation are difficult to completely eliminate. The difference in thermal expansion coefficients of different materials is an inherent physical phenomenon. Under extreme temperature gradients, the sticking force caused by deformation may far exceed the design expectations. Furthermore, the driving force of traditional electro-hydraulic servo valves (usually provided by torque motors or force motors) is designed primarily to meet the dynamic response requirements under normal operating conditions. Their maximum output force / torque often provides insufficient margin for the sudden and large sticking resistance generated under these extremely adverse conditions. When the sticking resistance momentarily exceeds the peak capacity of the drive mechanism, the valve core will not operate, causing system failure.

[0005] Therefore, it is urgent to propose a method that can significantly improve the output capacity of the core drive unit of the electro-hydraulic servo valve, so that when encountering abnormally large resistance caused by contaminants and temperature deformation, it can still provide sufficient driving torque or thrust, reliably overcome the clamping force caused by contamination, and ensure the normal movement and control function of the valve core. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and propose a method for increasing the driving force of an electro-hydraulic servo valve and an electro-hydraulic servo valve. By adjusting the stiffness of the feedback rod, the electromagnetic torque coefficient of the permanent magnet torque motor and the stiffness of the spring tube, the driving force can be increased from 35N to 65-68N, effectively overcoming the clamping force caused by contamination.

[0007] In order to achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for increasing the driving force of an electro-hydraulic servo valve, comprising the following steps: Equipped with benchmarked electro-hydraulic servo valves and electro-hydraulic servo valves to be calibrated with increased driving force; Obtain a benchmark pressure-current characteristic curve corresponding to the benchmark electro-hydraulic servo valve and a benchmark pressure-displacement characteristic curve of the pre-stage, and obtain a pressure-current characteristic curve corresponding to the electro-hydraulic servo valve to be calibrated and a pressure-displacement characteristic curve of the pre-stage; Based on the benchmark pressure-current characteristic curve and the benchmark pressure-displacement characteristic curve of the pre-stage, the benchmark displacement of the deflection plate of the benchmark electro-hydraulic servo valve under a constant input current is obtained; based on the pressure-current characteristic curve and the pressure-displacement characteristic curve of the pre-stage, the actual displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is obtained; The theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is calculated, and the pressure-displacement characteristic curve is further corrected by applying the deviation between the theoretical displacement and the actual displacement until the deviation between the actual displacement and the theoretical displacement is within a preset deviation range, thereby obtaining a corrected pressure-displacement characteristic curve; Find the target displacement of the target electro-hydraulic servo valve under constant input current on the calibrated pressure-displacement characteristic curve; The constraint conditions are constructed, specifically: the gain of the open-loop transfer function from the input current to the output flow of the electro-hydraulic servo valve to be calibrated remains unchanged; the bandwidth change of the electro-hydraulic servo valve to be calibrated is within a preset range; Based on the constraints and according to the preset driving force improvement scheme, the theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is increased to the reference displacement of the benchmark electro-hydraulic servo valve under a constant input current.

[0008] As a possible implementation method, the preset driving force enhancement scheme includes: reducing the spring tube stiffness, and / or increasing the electromagnetic torque coefficient of the permanent magnet torque motor and the feedback rod stiffness according to a preset ratio.

[0009] As a possible implementation method, the driving force is increased from 35N to 65-68N, the feedback rod stiffness is increased to 1510 N / m, the electromagnetic torque coefficient of the permanent magnet torque motor is increased to 0.6129 Nm / A, and the spring tube stiffness is reduced to 9 Nm / rad.

[0010] As a possible implementation method, a preset driving force improvement plan is formulated in the following way: Construct a positive boost model for the driving force of the electro-hydraulic servo valve to be calibrated: in, as the driving force; is the effective area at both ends of the valve core; is the pre-stage pressure gain; is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the load moment generated by the flow force of the pre-stage jet on the deflector, which is approximately zero; is the moment of inertia of the armature assembly; is a complex domain variable; is the viscous damping coefficient of the armature assembly; is the spring tube stiffness; is the magnetic spring stiffness of the permanent magnet torque motor; is the stiffness of the feedback rod; is the distance from the center of the deflection plate to the center of the ball on the feedback rod; The improvement parameters are determined based on the principle of not changing the overall structure of the armature assembly and the magnetic resistance and magnetic flux of the torque motor stage. The improvement parameters include the electromagnetic torque coefficient of the permanent magnet torque motor. , spring tube stiffness and feedback lever stiffness ; Configuration constraints: in, is the flow gain of the target electro-hydraulic servo valve; is the flow coefficient; is the bandwidth of the target electro-hydraulic servo valve; is the minimum bandwidth of the target electro-hydraulic servo valve; The maximum bandwidth of the target electro-hydraulic servo valve; is the open-loop amplification factor of the force feedback loop.

[0011] As a possible implementation method, the pressure-displacement characteristic curves of the benchmark electro-hydraulic servo valve and the pre-stage of the electro-hydraulic servo valve to be calibrated for increased driving force are obtained by the following method: Different valve core displacements are set to obtain the pressure difference between the two receiving ports corresponding to each displacement, and the pressure-displacement characteristic curve of the pre-stage is obtained by the point plotting method.

[0012] As a possible implementation method, the pressure-current characteristic curves of the benchmark electro-hydraulic servo valve and the electro-hydraulic servo valve to be calibrated whose driving force is to be increased are obtained by the following method: Different input currents were set to obtain the pressure difference between the two receiving ports corresponding to each input current, and the pressure-current characteristic curve was obtained using the plotting method.

[0013] As a possible implementation, the theoretical displacement is denoted as , calculated as follows: is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the armature angle.

[0014] As a possible implementation method, the armature angle It is calculated as follows: is the comprehensive stiffness of the torque motor; is the mechanical damping ratio of the torque motor; is a complex domain variable; is the natural frequency of the armature-baffle assembly; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the distance from the center of the deflection plate to the center of the ball on the feedback rod; is the stiffness of the feedback rod; is the valve core displacement; It is the load torque generated by the flow force of the pre-stage jet on the deflector plate, which is approximately zero.

[0015] In a second aspect, the present invention provides an electro-hydraulic servo valve, which uses the electro-hydraulic servo valve driving force enhancement method provided in the first aspect to enhance the driving force from 35N to 65-68N, so as to overcome the clamping force caused by contamination.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The method for increasing the driving force of an electro-hydraulic servo valve provided by the present invention can increase the driving force from 35N to 65-68N by adjusting the stiffness of the feedback rod, the electromagnetic torque coefficient of the permanent magnet torque motor, and the stiffness of the spring tube, effectively overcoming the clamping force caused by contamination.

[0017] 2. The method for increasing the driving force of an electro-hydraulic servo valve provided by the present invention has formulated an optimal solution for increasing the driving force of the servo valve. It can increase the driving force of the valve core while ensuring that the flow gain of the servo valve remains basically unchanged, and the adjusted parameters are all within a reasonable range.

[0018] 3. The method for improving the driving force of an electro-hydraulic servo valve provided by the present invention constructs a positive improvement model for the driving force of the electro-hydraulic servo valve to be calibrated, and determines the improvement parameters based on the principle of not changing the overall structure of the armature assembly and the magnetic resistance and magnetic flux of the torque motor stage, so that the driving force of the electro-hydraulic servo valve to be calibrated is improved to a level equivalent to that of the benchmark electro-hydraulic servo valve, and the scheme is highly feasible. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings: Figure 1 Schematic diagram of the structure of the electro-hydraulic servo valve in an embodiment of the present invention; Figure 2 Flowchart of a method for increasing the driving force of an electro-hydraulic servo valve according to an embodiment of the present invention; Figure 3 Schematic diagram of the driving force of the electro-hydraulic servo valve under different feedback rod stiffnesses in an embodiment of the present invention; Figure 4 Schematic diagram of the driving force of the electro-hydraulic servo valve under different spring tube stiffnesses when the feedback rod stiffness is 1150 N / mm in an embodiment of the present invention; Figure 5 Schematic diagram of the proportional relationship between the stiffness of the feedback rod and the electromagnetic torque coefficient of the permanent magnet torque motor in an embodiment of the present invention.

[0020] 1-coil, 2-armature assembly, 3-right receiving hole, 4-spring tube, 5-V-groove, 6-feedback lever, 7-right load chamber, 8-valve core, 9-right control chamber, 10-upper magnetic conductor, 11-lower magnetic conductor, 12-left receiving hole, 13-deflector plate, 14-jet disk, 15-filter screen, 16-left load chamber, 17-left control chamber, 18-valve sleeve, 19-base. DETAILED DESCRIPTION

[0021] In order to clearly describe the technical solutions of the embodiments of the present application, in the embodiments of the present application, the terms "first", "second", etc. are used to distinguish the same or similar items with basically the same function and role. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and the order is not limited. Those skilled in the art can understand that the terms "first", "second", etc. do not limit the quantity and execution order, and the terms "first", "second", etc. also do not necessarily mean different.

[0022] It should be noted that in the present application, the words "exemplary" or "for example" are used to mean serving as an example, instance, or illustration. Any embodiment or design presented as "exemplary" or "for example" in the present application should not be interpreted as being more preferred or advantageous than other embodiments or design solutions. Rather, the use of the words "exemplary" or "for example" is intended to present related concepts in a specific way.

[0023] In the present application, "at least one" means one or more, and "multiple" means two or more. The "and / or" describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the following three cases: A exists alone, A and B exist together, and B exists alone, where A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it. The following "at least one" or similar expressions mean any combination of these items, including any combination of single or multiple items. For example, at least one of a, b or c can represent: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b and c can be single or multiple.

[0024] The embodiments of the present application aim to provide an electro-hydraulic servo valve driving force improving method and an electro-hydraulic servo valve. By adjusting the feedback rod stiffness, the permanent magnet torque motor electromagnetic torque coefficient and the spring tube stiffness, the driving force can be improved from 35N to 65-68N, effectively overcoming the clamping force generated by pollution.

[0025] In a first aspect, the embodiments of the present application provide an electro-hydraulic servo valve driving force improving method. Referring to Figure 1The electro-hydraulic servo valve comprises a coil 1, an armature assembly 2, a right receiving hole 3, a spring tube 4, a V-groove 5, a feedback rod 6, a right load chamber 7, a valve core 8, a right control chamber 9, an upper magnetic conductor 10, a lower magnetic conductor 11, a left receiving hole 12, a deflector plate 13, a jet disk 14, a filter 15, a left load chamber 16, a left control chamber 17, a valve sleeve 18, and a base 19. The armature assembly 2 and spring tube 4 form a T-shaped frame. When the torque motor of the electro-hydraulic servo valve operates, it first magnetizes and polarizes the lower magnetic conductor 11. A direct current flowing through the coil 1 causes the magnetic force in the diagonal air gap to change, and the magnitude of the current is proportional to the rotation angle of the armature assembly 2. The armature assembly 2, spring tube 4, and feedback rod 6 are rigidly connected and supported by the thin wall of the spring tube 4. Oil flows through the oil supply port and the oil guide port of the feedback rod 6, then enters the jet disk. The swinging of the armature assembly 2 causes the position of the guide port on the feedback lever 6 to change relative to the receiving port of the jet disk 14, thereby generating a pressure differential between the left control chamber 17 and the right control chamber 9 at the outlet of the jet amplifier receiver at the deflector plate 13. When the feedback mechanism is activated, the current in the coil 1 generates a magnetic force at the end of the armature assembly 2. This magnetic force rotates the armature assembly 2, which, supported by the spring tube 4, drives the feedback lever 6. This changes the position of the guide port relative to the receiving port of the jet disk 14, causing the jet to flow toward one end of the valve core 8, creating a pressure differential across the valve core 8. This pressure differential moves the valve core 8, simultaneously connecting the supply oil Ps to the control chamber and the other chamber to the return oil Pr. The valve core 8 pushes the ball at the end of the feedback lever 6, creating a feedback torque on the armature assembly 2. When the feedback torque balances the torque generated by the current, the valve core 8 stops at a certain position. The displacement of the valve core 8 is proportional to the input current. At a certain pressure, the flow rate to the load is proportional to the displacement of the valve core 8.

[0026] See also Figure 2 The driving force improvement method provided in this embodiment includes the following steps: Equipped with benchmarked electro-hydraulic servo valves and electro-hydraulic servo valves to be calibrated with increased driving force; The driving force increasing method provided in this embodiment is to increase the driving force of the electro-hydraulic servo valve to be calibrated, the driving force of which is to be increased, to a level equivalent to the driving force of the benchmark electro-hydraulic servo valve.

[0027] Obtain a benchmark pressure-current characteristic curve corresponding to the benchmark electro-hydraulic servo valve and a benchmark pressure-displacement characteristic curve of the pre-stage, and obtain a pressure-current characteristic curve corresponding to the electro-hydraulic servo valve to be calibrated and a pressure-displacement characteristic curve of the pre-stage; As a possible implementation method, the pressure-displacement characteristic curves of the benchmark electro-hydraulic servo valve and the pre-stage of the electro-hydraulic servo valve to be calibrated for increased driving force are obtained by the following method: Different valve core displacements are set to obtain the pressure difference between the two receiving ports corresponding to each displacement, and the pressure-displacement characteristic curve of the pre-stage is obtained by the point plotting method.

[0028] As an example, different valve core displacements are set through flow field simulation software to obtain the pressure difference between the two receiving ports corresponding to each displacement, and the pressure-displacement characteristic curve of the pre-stage is obtained by the point plotting method.

[0029] As another possible implementation, the pressure-current characteristic curves of the benchmark electro-hydraulic servo valve and the electro-hydraulic servo valve to be calibrated, whose driving force is to be increased, are obtained by the following method: Set different input currents, obtain the pressure difference between the two receiving ports corresponding to each input current, and use the plotting method to obtain the pressure-current characteristic curve; Based on the benchmark pressure-current characteristic curve and the benchmark pressure-displacement characteristic curve of the pre-stage, the benchmark displacement of the deflection plate of the benchmark electro-hydraulic servo valve under a constant input current is obtained; based on the pressure-current characteristic curve and the pressure-displacement characteristic curve of the pre-stage, the actual displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is obtained; The theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is calculated, and the pressure-displacement characteristic curve is further corrected by applying the deviation between the theoretical displacement and the actual displacement until the deviation between the actual displacement and the theoretical displacement is within a preset deviation range, thereby obtaining a corrected pressure-displacement characteristic curve; As an example, according to the torque balance equation, the constant input current of the benchmark electro-hydraulic servo valve is calculated. Marking displacement of the lower deflection plate , and the electro-hydraulic servo valve to be calibrated at a constant input current Actual displacement of the lower deflector plate , calculate and obtain the constant input current of the electro-hydraulic servo valve to be calibrated Theoretical displacement of the lower deflector plate , compared with the theoretical displacement and the actual displacement of the electro-hydraulic servo valve to be calibrated Based on the deviation between the two, the pressure-displacement characteristic curve is corrected and the constant input current of the benchmark electro-hydraulic servo valve is found on the curve. Correction value under .

[0030] As a possible implementation, the theoretical displacement is denoted as , calculated as follows: is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the armature angle.

[0031] As a possible implementation method, the armature angle is calculated by the following way: is the total stiffness of the torque motor; is the mechanical damping ratio of the torque motor; is a complex domain variable; is the natural frequency of the armature flapper assembly; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the distance from the rotation center of the armature flapper assembly to the center of the deflection plate; is the distance from the center of the deflection plate to the center of the feedback rod ball; is the stiffness of the feedback rod; is the spool displacement; is the load torque of the deflection plate generated by the fluid force of the pre-stage fluidic jet, which is approximately zero.

[0032] finds the reference displacement of the reference electro-hydraulic servo valve under the reference input current on the corrected pressure-displacement characteristic curve; constructs the constraint condition, specifically: the open-loop transfer function gain of the input current to the output flow of the electro-hydraulic servo valve to be calibrated is unchanged; the bandwidth variation of the electro-hydraulic servo valve to be calibrated is within the preset range; based on the constraint condition, the theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated is increased to the reference displacement of the reference electro-hydraulic servo valve under the reference input current according to the preset driving force improvement scheme.

[0033] As a possible implementation manner, the preset driving force improvement scheme includes: reducing the spring tube stiffness, and / or increasing the electromagnetic torque coefficient of the permanent magnet torque motor and the stiffness of the feedback rod by a preset proportion; As a possible implementation manner, the preset driving force improvement scheme is formulated by the following way: constructs a driving force forward improvement model of the electro-hydraulic servo valve to be calibrated: wherein, is the driving force; is the acting area at both ends of the spool; is the pre-stage pressure gain; is the distance from the rotation center of the armature flapper assembly to the center of the deflection plate; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the load torque of the deflection plate generated by the fluid force of the pre-stage fluidic jet, which is approximately zero; is the moment of inertia of the armature assembly; is a complex domain variable; is the viscous damping coefficient of the armature assembly; is the spring tube stiffness; is the magnetic spring stiffness of the permanent magnet torque motor; is the stiffness of the feedback rod; is the distance from the center of the deflection plate to the center of the ball on the feedback rod; Improved parameters include permanent magnet torque motor electromagnetic torque coefficient , spring tube stiffness and feedback lever stiffness ; As an example, a step signal with an amplitude of 33mA is used as input to simulate the driving force of the electro-hydraulic servo valve under different feedback rod stiffness when the spring tube stiffness is 11.60Nm / rad. The simulation results are as follows: Figure 3 As shown. Among them, Figure 3 In (a), the stiffness of the feedback rod is 1120 N / m. Figure 3 The stiffness of the feedback rod in (b) is 1180 N / m. Figure 3 The stiffness of the feedback rod in (c) is 1450 N / m. Figure 3 The stiffness of the feedback rod in (d) is 1510 N / m. Figure 3 The stiffness of the feedback rod in the middle (e) is 1320 N / m. Figure 3 The stiffness of the feedback rod in the middle (f) is 1350 N / m. Figure 3 The stiffness of the feedback rod in the middle (g) is 1380 N / m.

[0034] based on Figure 3 It can be seen that the driving force values ​​corresponding to different feedback lever stiffness are shown in Table 1: Table 1 Driving force values ​​corresponding to different feedback lever stiffness It can be seen that with the increase of the stiffness of the feedback rod, the driving force of the electro-hydraulic servo valve decreases to a certain extent, from 40N to about 35N, but the reduction is not obvious. Moreover, with the increase of the stiffness of the feedback rod, the volatility of the driving force of the electro-hydraulic servo valve increases.

[0035] When the stiffness of the feedback rod is 1150 N / mm, the driving force of the electro-hydraulic servo valve under different spring tube stiffness is as follows: Figure 4 As shown. Among them, Figure 4 The spring tube stiffness in (a) is 10.95 Nm / rad. Figure 4 The spring tube stiffness in (b) is 11.60 Nm / rad. Figure 4 The spring tube stiffness in (c) is 9.60 Nm / rad. Figure 4 The spring tube stiffness in (d) is 9.00 Nm / rad.

[0036] based on Figure 4 It can be seen that the driving force values ​​corresponding to different spring tube stiffness are shown in Table 2: Table 2 Driving force values ​​corresponding to different spring tube stiffness It can be seen that as the stiffness of the spring tube decreases, the driving force of the electro-hydraulic servo valve increases significantly, and as the stiffness of the spring rod changes, the driving force fluctuation of the electro-hydraulic servo valve changes to a certain extent, but they are not completely correlated. It is necessary to comprehensively consider the stiffness of the feedback rod and the stiffness of the spring tube.

[0037] Configuration constraints: in, is the flow gain of the target electro-hydraulic servo valve; is the flow coefficient; is the bandwidth of the target electro-hydraulic servo valve; is the minimum bandwidth of the target electro-hydraulic servo valve; The maximum bandwidth of the target electro-hydraulic servo valve; is the open-loop amplification factor of the force feedback loop.

[0038] By constraints It can be seen that the stiffness of the feedback rod is proportional to the electromagnetic torque coefficient of the permanent magnet torque motor, as shown in Figure 5 shown.

[0039] Based on the positive improvement model and constraint conditions of the electro-hydraulic servo valve driving force to be calibrated, it can be seen that the driving force of the servo valve can be improved by increasing the electromagnetic torque coefficient of the permanent magnet torque motor while keeping the input current unchanged. Magnetic spring stiffness of permanent magnet torque motor Or reduce the spring tube stiffness Feedback lever stiffness At the same time, if you want to ensure the flow gain of the servo valve Basically unchanged, adjust the electromagnetic torque coefficient of the permanent magnet torque motor and feedback lever stiffness When and The proportional relationship remains basically unchanged.

[0040] As a possible implementation method, the driving force is increased from 35N to 65-68N, the feedback rod stiffness is increased to 1510 N / m, the electromagnetic torque coefficient of the permanent magnet torque motor is increased to 0.6129 Nm / A, and the spring tube stiffness is reduced to 9 Nm / rad.

[0041] In a second aspect, an embodiment of the present invention provides an electro-hydraulic servo valve, which applies the electro-hydraulic servo valve driving force enhancement method provided in the first aspect to enhance the driving force from 35N to 65-68N to overcome the clamping force caused by contamination.

[0042] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by reviewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality. A single processor or other unit may implement several functions listed in the claims. The fact that certain measures are recorded in mutually different dependent claims does not mean that these measures cannot be combined to produce good results.

[0043] Although the present invention has been described with reference to specific features and embodiments thereof, it will be apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the invention. It will be apparent that various modifications and variations may be made to the present invention by those skilled in the art without departing from the spirit and scope of the invention. Thus, the present invention is intended to include such modifications and variations as fall within the scope of the claims of the present invention and their equivalents.

Claims

1. A method for increasing the driving force of an electro-hydraulic servo valve, characterized in that: The steps include: Equipped with benchmarked electro-hydraulic servo valves and electro-hydraulic servo valves to be calibrated with increased driving force; Obtain a benchmark pressure-current characteristic curve corresponding to the benchmark electro-hydraulic servo valve and a benchmark pressure-displacement characteristic curve of the pre-stage, and obtain a pressure-current characteristic curve corresponding to the electro-hydraulic servo valve to be calibrated and a pressure-displacement characteristic curve of the pre-stage; Based on the benchmark pressure-current characteristic curve and the benchmark pressure-displacement characteristic curve of the pre-stage, the benchmark displacement of the deflection plate of the benchmark electro-hydraulic servo valve under a constant input current is obtained; Based on the pressure-current characteristic curve and the pressure-displacement characteristic curve of the pre-stage, the actual displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is obtained; The theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is calculated, and the pressure-displacement characteristic curve is further corrected by applying the deviation between the theoretical displacement and the actual displacement until the deviation between the actual displacement and the theoretical displacement is within a preset deviation range, thereby obtaining a corrected pressure-displacement characteristic curve; Find the target displacement of the target electro-hydraulic servo valve under constant input current on the calibrated pressure-displacement characteristic curve; The constraint conditions are constructed, specifically: the gain of the open-loop transfer function from the input current to the output flow of the electro-hydraulic servo valve to be calibrated remains unchanged; the bandwidth change of the electro-hydraulic servo valve to be calibrated is within a preset range; Based on the constraints and according to the preset driving force improvement scheme, the theoretical displacement of the deflection plate of the electro-hydraulic servo valve to be calibrated under a constant input current is increased to the reference displacement of the benchmark electro-hydraulic servo valve under a constant input current.

2. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 1, characterized in that: The preset driving force enhancement scheme includes: reducing the spring tube stiffness, and / or increasing the electromagnetic torque coefficient of the permanent magnet torque motor and the feedback rod stiffness according to a preset ratio.

3. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 2, characterized in that: The driving force is increased from 35N to 65-68N, the feedback rod stiffness is increased to 1510 N / m, the electromagnetic torque coefficient of the permanent magnet torque motor is increased to 0.6129 Nm / A, and the spring tube stiffness is reduced to 9 Nm / rad.

4. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 2, wherein: Develop a preset driving force improvement plan by: Construct a positive boost model for the driving force of the electro-hydraulic servo valve to be calibrated: in, as the driving force; is the effective area at both ends of the valve core; is the pre-stage pressure gain; is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the load moment generated by the flow force of the pre-stage jet on the deflector, which is approximately zero; is the moment of inertia of the armature assembly; is a complex domain variable; is the viscous damping coefficient of the armature assembly; is the spring tube stiffness; is the magnetic spring stiffness of the permanent magnet torque motor; is the stiffness of the feedback rod; is the distance from the center of the deflection plate to the center of the ball on the feedback rod; The improvement parameters are determined based on the principle of not changing the overall structure of the armature assembly and the magnetic resistance and magnetic flux of the torque motor stage. The improvement parameters include the electromagnetic torque coefficient of the permanent magnet torque motor. , spring tube stiffness and feedback lever stiffness ; Configuration constraints: in, is the flow gain of the target electro-hydraulic servo valve; is the flow coefficient; is the bandwidth of the target electro-hydraulic servo valve; is the minimum bandwidth of the target electro-hydraulic servo valve; The maximum bandwidth of the target electro-hydraulic servo valve; is the open-loop amplification factor of the force feedback loop.

5. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 1, characterized in that: The pressure-displacement characteristic curves of the benchmark electro-hydraulic servo valve and the pre-stage of the electro-hydraulic servo valve to be calibrated with increased driving force are obtained by the following method: Different valve core displacements are set to obtain the pressure difference between the two receiving ports corresponding to each displacement, and the pressure-displacement characteristic curve of the pre-stage is obtained by the point plotting method.

6. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 1, characterized in that: The pressure-current characteristic curves of the benchmark electro-hydraulic servo valve and the electro-hydraulic servo valve to be calibrated for increased driving force are obtained by the following method: Different input currents were set to obtain the pressure difference between the two receiving ports corresponding to each input current, and the pressure-current characteristic curve was obtained using the plotting method.

7. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 1, characterized in that: The theoretical displacement is denoted as , calculated as follows: is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the armature angle.

8. The method for increasing the driving force of an electro-hydraulic servo valve according to claim 1, characterized in that: Armature angle It is calculated as follows: is the comprehensive stiffness of the torque motor; is the mechanical damping ratio of the torque motor; is a complex domain variable; is the natural frequency of the armature-baffle assembly; is the electromagnetic torque coefficient of the permanent magnet torque motor; is the control current of the input control coil; is the distance from the center of rotation of the armature-flap assembly to the center of the deflector plate; is the distance from the center of the deflection plate to the center of the ball on the feedback rod; is the stiffness of the feedback rod; is the valve core displacement; It is the load torque generated by the flow force of the pre-stage jet on the deflector plate, which is approximately zero.

9. An electro-hydraulic servo valve, characterized in that: The electro-hydraulic servo valve driving force increasing method according to any one of claims 1 to 8 is applied to increase the driving force from 35N to 65-68N to overcome the clamping force caused by contamination.

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