Underwater hydraulic system compensation mechanism integrating filtering and pressure self-adaptive adjustment and control method

Abstract

The invention discloses an underwater hydraulic system compensation mechanism integrating filtering and pressure self-adaptive adjustment and a control method, and belongs to the field of hydraulic control of deep sea equipment. The problems that an existing compensation mechanism is lagged in pressure response, weak in anti-pollution capacity and high in maintenance cost are solved. The mechanism comprises a data acquisition unit, a filtering unit, a processing unit, an execution unit and a two-stage filtering module, wherein the two-stage filtering module adopts a rough filtering and fine filtering composite structure; the data acquisition unit acquires relevant parameters, the filtering unit purifies pressure difference data through moving average and Kalman filtering, the processing unit optimizes dynamic response of a valve element through a transfer function based on a depth self-adaptive adjustment threshold value and PI control parameters, and the execution unit corrects displacement in a closed loop mode. The hydraulic servo valve is adaptive to the full-sea-depth working condition, the pressure balance response time is shortened to be within 0.1 s, the impurity interception efficiency exceeds 98%, the operation and maintenance cost is reduced by 40%, and the operation stability and precision of the hydraulic servo valve are improved.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control for deep-sea equipment, specifically to pressure compensation and anti-pollution design for underwater hydraulic servos. Background Technology

[0002] As the "hydraulic brain" of deep-sea equipment (such as underwater robots, deep-sea mining equipment, and seabed observation systems), the core function of underwater hydraulic systems is to drive the actuators by controlling the volume and pressure of hydraulic fluid. The pressure balance inside and outside the equipment directly determines its control accuracy and reliability. Existing technologies for deep-sea pressure compensation mainly have the following limitations: 1. Delayed pressure compensation Traditional compensation structures often rely on fixed orifice compensation to achieve pressure balance (such as patent 201210435791.1). When the pressure in the deep-sea environment rises or falls suddenly, the fixed compensation orifice cannot dynamically adjust the flow area, which can easily cause the pressure difference between the inside and outside of the valve body to exceed the safety threshold instantaneously, leading to the overall failure of the servo valve.

[0003] 2. Insufficient pollution resistance Traditional compensation mechanisms use only a single-layer filter (with a pore size of 100-200μm). Tiny impurities can easily penetrate the filter and enter the control element, resulting in decreased control accuracy and shortened equipment lifespan.

[0004] 3. High maintenance costs The existing compensation structure's filter components and seals are mostly designed as a single unit, requiring the entire equipment to be disassembled for replacement. This is not only time-consuming (each maintenance takes 6 to 10 hours), but also prone to introducing new impurities during disassembly, increasing the risk of secondary failures of the original equipment. In addition, the combined effects of high pressure in the deep sea and seawater corrosion shorten the original service life, requiring frequent replacements, which significantly increases the operation and maintenance costs of deep-sea equipment and the probability of operational interruptions.

[0005] In summary, existing deep-sea pressure compensation solutions are no longer able to meet the requirements of full-ocean-depth, long-cycle, and high-precision deep-sea equipment operations in terms of pressure response speed, pollution resistance, and ease of maintenance. There is an urgent need for a pressure compensation technology solution that can adapt to the deep-sea environment and balance performance and reliability. Summary of the Invention

[0006] This invention addresses the technical shortcomings of existing underwater hydraulic servo valve compensation mechanisms in extreme deep-sea environments (high pressure, high pollution), such as delayed pressure compensation response, weak anti-pollution capability, and high maintenance costs. It provides an integrated filtration and pressure adaptive regulation underwater hydraulic system compensation mechanism and control method, aiming to improve the pressure compensation accuracy, anti-pollution performance, and operational stability of hydraulic servo valves under full ocean depth (0–11000 meters) conditions, while reducing maintenance costs. This invention is suitable for the long-term stable operation requirements of deep-sea robots, seabed mining equipment, and deep-sea observation system equipment.

[0007] To achieve the above objectives, this invention designs a pressure-adaptive underwater hydraulic system compensation mechanism, including a data acquisition unit, a data filtering unit, a data processing unit, an execution unit, and a two-stage filtration module. The data acquisition unit, data filtering unit, data processing unit, and execution unit are sequentially connected to form a closed loop. The two-stage filtration module is positioned along the path of the hydraulic oil entering the underwater working equipment. The data acquisition unit collects data on the equipment's diving depth, external seawater pressure, internal hydraulic oil pressure, and valve core displacement, and sends this data to the data filtering unit. The data filtering unit filters and selects the collected data to obtain the pressure difference data between the inside and outside of the equipment and sends it to the data processing unit. The data processing unit determines the depth range of the equipment based on the pressure difference data and provides a corresponding displacement and execution speed control strategy for the execution unit. The execution unit receives the control strategy and executes the control commands, while simultaneously feeding back the actual valve core displacement to the data processing unit.

[0008] Furthermore, the dual-stage filtration module includes a coarse filtration unit and a fine filtration unit arranged sequentially along the fluid flow direction; the coarse filtration unit is in the form of a sintered metal mesh with a pore size of 50-100μm; the surface of the fine filtration unit is coated with a nano-ceramic filter screen; the outer side of the coarse filtration unit is detachable for cleaning or replacement.

[0009] Furthermore, the data filtering unit processes the data using a combination of moving average filtering and Kalman filtering; the moving average filtering applies the raw pressure difference ΔP over n consecutive sampling periods. i Perform an arithmetic mean to obtain the smoothed average pressure difference. Based on the filtering results of the previous time step (k-1) and combined with default noise Through formula Predict the current pressure differential state; then calculate the Kalman gain. In establishing ,in The prediction error covariance is given by R, where R represents the measurement noise, and the actual measured values ​​are also considered. Establish formula Correcting the predicted values ​​yields the final filtered pressure difference. .

[0010] Furthermore, the data processing unit establishes a pressure differential based on the principles of flow continuity and force balance of the hydraulic servo valve. The relationship equation between the valve core displacement S and the flow rate formula in fluid mechanics; ;in For flow coefficient, The flow area corresponding to the valve core displacement is linearly related to the displacement, approximately... , The density of the hydraulic oil, The pressure difference between the inside and outside of the valve body is used as the input quantity. Simplify the flow formula ,in The flow gain is a constant. Establish the mechanical equations of the execution unit based on Newton's second law. Where m is the total mass of the valve core and push rod, B is the viscous damping coefficient, and K is the spring stiffness. Let be the first derivative of the valve core displacement with respect to time. Let F be the second derivative of the valve core displacement with respect to time, and F be the driving force, which is balanced by the hydrodynamic force generated by the pressure difference and the motor driving force. Flow equation Substituting the equations of motion of the execution unit and linearizing them, we get... ,in Consider it as the rated pressure difference, and consider it as a constant; let Using the pressure difference to force conversion coefficient, the linearized time-domain equations of pressure difference and valve core displacement are obtained. ; Performing a Plas transform on the time-domain equation, the input... and Transforming from the time domain to the complex frequency domain, the transfer function of pressure difference-valve spool displacement is obtained as follows: This transfer function describes the dynamic influence characteristics of valve core displacement on differential pressure in the complex frequency domain. The dynamic response speed and accuracy of valve core displacement can be optimized by adjusting the controller parameters of the actuator unit.

[0011] Furthermore, the data processing unit incorporates a PI controller, which outputs... At the same time, a threshold adaptively corrected based on depth H is introduced. and The data processing unit dynamically adjusts according to depth H, increasing sensitivity in shallow waters and maintaining stability in deep waters. When H < 3000m, the shallow sea area is:

[0012] When H > 3000m, the deep-sea range is: Keep the default values ​​and avoid over-adjustment; When H < 3000m, the shallow sea area is: Maintain default values ​​and respond quickly; When H > 3000m, the deep-sea range is: In the formula, 8000 represents the depth span of "3000m to 11000m".

[0013] Furthermore, the valve core displacement control logic of the execution unit is as follows: when the external seawater pressure Pext > Pint, the external pressure is high and the compensation orifice area needs to be increased, thus controlling the valve core displacement. ; When Pext < Pint, the internal pressure is high, and the area of ​​the compensation orifice needs to be reduced to control the valve core displacement. The negative sign indicates that the displacement direction is opposite. S is the displacement of the valve core relative to the initial position. Positive means "increasing area direction" and negative means "decreasing area direction".

[0014] Furthermore, after the execution unit executes the command, if there is a deviation between the actual displacement of the valve core and the commanded displacement, or if the differential pressure exceeds the limit after adjustment, compensation control is required. Establish a formula for correcting valve core displacement deviation. ; For command signals, This is the actual displacement. For deviation, Correction factor, if Then the corrected instruction shift, , =0.3, proportional correction, quickly reducing displacement deviation.

[0015] Furthermore, if the differential pressure still exceeds the limit after adjustment, increase the opening of the backup channel. , This is the initial opening of the backup channel. To limit overpressure, the maximum opening cannot exceed 1.5 times the area of ​​the main channel.

[0016] Furthermore, the compensation mechanism is adapted to working conditions at depths of 0 to 11,000 meters and is suitable for the hydraulic control systems of deep-sea robots, seabed mining equipment, or deep-sea observation systems.

[0017] The beneficial technical effects of the present invention are as follows: Compared with the prior art, the significant advantages of the present invention are as follows: 1. More precise pressure compensation: Through the dynamic flow area control of the adaptive adjustment module and the closed-loop feedback, the pressure balance response time is shortened from the traditional 0.5s to within 0.1s, which can be adapted to the full ocean depth 110MPa high pressure working condition, and the differential pressure control accuracy is improved to ±0.1MPa, effectively avoiding leakage of seals; 2. Longer lifespan and resistance to contamination: The dual-stage filtration structure increases the impurity interception efficiency to over 98%, extends the maintenance cycle by 60%, and the oil filter design eliminates the need for disassembly, reducing operation and maintenance costs by 40%. 3. Wider range of applications: In addition to traditional deep-sea hydraulic servo valves, it can be extended to underwater robot propulsion systems, hydraulic valve groups for seabed mining equipment, and other scenarios with higher requirements for pressure compensation and anti-interference, and has good versatility and industrialization value. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a block diagram of the control process of the underwater hydraulic compensation mechanism; Figure 2 For control logic diagram. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] The features and illustrative embodiments of various aspects of the present invention will now be described in detail. Numerous specific details are set forth in the following detailed description to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without requiring some of these specific details. The following description of embodiments is merely intended to provide a better understanding of the invention by illustrating examples of the invention. The invention is by no means limited to any specific setups and methods set forth below, but covers any improvements, substitutions, and modifications to structures, methods, and devices without departing from the spirit of the invention. Well-known structures and techniques are not shown in the drawings and the following description to avoid unnecessarily obscuring the invention.

[0022] It should be noted that, unless otherwise specified, the embodiments of the present invention and the features thereof can be combined with each other, and the various embodiments can be referenced and cited in each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.

[0024] This invention designs a pressure-adaptive underwater hydraulic system compensation mechanism, which includes a data acquisition unit, a data filtering unit, a data processing unit, and an execution unit. The data acquisition unit collects data on the equipment's diving depth, ambient pressure, and valve core displacement, and sends this data to the data filtering unit. The filtered data is then used to obtain the pressure difference data between the inside and outside of the equipment, which is sent to the data processing unit. Based on this pressure difference data, the depth range of the equipment is determined, and control strategies for the displacement and execution speed of the corresponding execution unit are provided according to different depth ranges. The specific control method includes the following steps: Step 1: The data acquisition unit first collects the external seawater pressure. Through formula Calculate the original pressure difference inside and outside the device.

[0025] Step 2: The data filtering unit uses moving average filtering and Kalman wave filtering to analyze the acquired pressure difference. Purification and interference elimination are carried out.

[0026] First, a moving average filter is used: the raw pressure difference within n consecutive sampling periods is... Perform an arithmetic mean to obtain the smoothed average pressure difference. ,in This represents the original pressure difference.

[0027] Using Kalman waves: as a complement to moving average filtering, to further reduce random noise and provide more accurate state estimation. Based on the filtering results of the previous time step (k-1). and combined with default noise Through formula + Predict the current pressure differential state; then calculate the Kalman gain. ,in For the prediction error covariance, R is the measurement noise, in establishing Combined with actual measured values Establish formula Correcting the predicted values ​​yields the final filtered pressure difference. .

[0028] Step 3: The data processing unit provides control strategies for the displacement and execution speed of the corresponding execution unit based on different depth ranges.

[0029] Based on the principles of flow continuity and force balance in hydraulic servo valves, a pressure differential is established. The relationship equation between the valve core displacement S and the flow rate formula in fluid mechanics. .in For flow coefficient, This represents the flow area corresponding to the valve core displacement, and it has a linear relationship with the displacement. = , The density of the hydraulic oil, : Pressure difference between the inside and outside of the valve body (input quantity), carried over Simplify the flow formula = ,in This represents the flow gain (constant).

[0030] Furthermore, the mechanical equations of the execution unit are established based on Newton's second law. F, where m is the total mass of the valve core and push rod, B is the viscous damping coefficient, K is the spring stiffness, and F is the driving force (balanced between the hydrodynamic force generated by the pressure difference and the motor driving force).

[0031] Furthermore, the flow equation = Substituting the equations of motion of the execution unit and linearizing them, we get... = ,in Consider it as the rated differential pressure, and consider it as a constant. Let... (Pressure difference to force conversion coefficient), and by rearranging, we obtain the linearized time-domain equations for pressure difference and valve core displacement. = (t). (1) Furthermore, by performing a Plas transform on the time-domain equation (1), the input... (t) and Transforming from the time domain to the complex frequency domain, the transfer function of pressure difference-valve spool displacement is obtained as follows: = This transfer function describes the dynamic influence characteristics of valve core displacement on differential pressure in the complex frequency domain. The dynamic response speed and accuracy of valve core displacement can be optimized by adjusting the controller parameters of the actuator.

[0032] Furthermore, substituting the obtained transfer function into... ,get At the same time, a threshold adaptively corrected based on depth H is introduced. The data processing unit dynamically adjusts based on depth H, increasing sensitivity in shallow waters and maintaining stability in deep waters.

[0033] When H < 3000m (shallow sea):

[0034] When H > 3000m (deep sea): (Keep the default values ​​to avoid over-adjustment) When H < 3000m (shallow sea): ( ) When H > 3000m (deep sea): (8000 represents a depth range of 3000m to 11000m) Furthermore, the data processing unit processes the filtered differential pressure data. The calculation is performed to obtain the specific equation for the valve core displacement control quantity S, and to clarify the displacement direction and magnitude of the valve core under different depths and pressure differentials.

[0035] Furthermore, when Pext > Pint (external pressure is high, requiring an increase in the area of ​​the compensation orifice): When Pext < Pint (high internal pressure, need to reduce compensation orifice area): The negative sign indicates that the displacement direction is opposite. S is the displacement of the valve core relative to the initial position. Positive means "increasing area direction" and negative means "decreasing area direction".

[0036] Step 4: After the execution unit executes the corresponding command, if there is a deviation between the valve core displacement and the commanded displacement, or if the differential pressure exceeds the limit after adjustment, compensation is required.

[0037] Furthermore, a formula for correcting valve core displacement deviation is established. . Correction factor, if Then the corrected instruction shift, ( =0.3, proportional correction, quickly reducing displacement deviation).

[0038] Furthermore, if after adjustment Still exceeding limits, increase the opening of the backup channel. , This is the initial opening of the backup channel. To limit overpressure, the maximum opening cannot exceed 1.5 times the area of ​​the main channel.

[0039] By cyclically executing the above four steps, this invention achieves end-to-end adaptive pressure control from "data acquisition - data filtering - data processing - data execution", ensuring the pressure compensation accuracy, dynamic response speed and long-term operational stability of deep-sea equipment under complex working conditions at depths of 0 to 11,000 m.

[0040] Furthermore, the compensation mechanism also includes a two-stage filtration module. This module, along the path of the hydraulic oil entering the underwater working equipment, sequentially sets up a "coarse filter unit + fine filter unit" composite structure. The coarse filter unit is in the form of a sintered metal mesh with a pore size of 50-100μm, which can intercept large particles such as metal impurities and silt. Moreover, the coarse filter can be cleaned or replaced without disassembling the main body of the equipment. The fine filter unit uses a nano-coated filter with a coating thickness of 5-10μm. Utilizing the adsorption properties of nano-ceramics, it filters metal powder, improving the filtration accuracy by 3-5 times compared to traditional single-layer filters, thereby extending the service life of the original equipment.

[0041] Example 1: A compensation mechanism and control method for an underwater hydraulic system integrating filtration and adaptive pressure regulation, specifically implemented including the following steps: Step 1: The data acquisition unit first collects the external seawater pressure. Through formula Calculate the original pressure difference inside and outside the device.

[0042] Diving depth: H = 1000m (shallower than 3000m) External seawater pressure: ≈10MPa (Approximate calculation: 10m water depth ≈ 0.1MPa) Internal hydraulic oil pressure: = 9.95 MPa (Initial state has a slight negative pressure difference) Initial pressure difference: ΔP = |10 - 9.95| = ​​0.05 MPa Step 2: The data filtering unit uses moving average filtering and Kalman wave filtering to analyze the acquired pressure difference. Purification and interference elimination are performed. Pressure difference calculation and filtering assume the original pressure differences from five consecutive samples are: [0.05, 0.052, 0.048, 0.053, 0.049] MPa. Furthermore, we first employ a moving average filter:

[0043] =(0.05+0.052+0.048+0.053+0.049) / 5=0.0504MPa Furthermore, Kalman waves are used as a supplement to the moving average filter to further reduce random noise and provide more accurate state estimation. Assume the filtering result at the previous time step... =0.049MPa, combined with default noise Through formula + Predict the current pressure differential state and finally obtain the filtered pressure differential.

[0044] Step 3: The data processing unit provides control strategies for the displacement and execution speed of the corresponding execution unit based on different depth ranges. Pressure direction determination: (10 MPa)> (9.95 MPa) → The area of ​​the compensation hole needs to be increased, and the valve core displacement is positive.

[0045] Furthermore, the threshold is adaptively corrected based on depth H. The data processing unit dynamically adjusts according to depth H, increasing sensitivity in shallow waters and maintaining stability in deep waters. Controller output: Proportional portion: 0.2 mm / MPa·0.051MPa = 0.0102 mm, Integral part: Assuming this is the first control cycle, the integral term accumulates from zero. = 0.1 mm / (MPa s)·0.051 MPa·0.01s ≈0.000051mm, control quantity Since H = 1000m < 3000m, the threshold ΔP1 is corrected as follows: =ΔP1=0.1-0.02·(3000-1000) / 3000=0.1-0.02·(2 / 3)≈0.0867 MPa, threshold ΔP2 correction: ΔP2 =0.5MPa (keep the default value).

[0046] Step 4: After the execution unit executes the corresponding command, if there is a deviation between the valve core displacement and the commanded displacement, or if the differential pressure exceeds the limit after adjustment, compensation is required.

[0047] Furthermore, displacement deviation correction assumes the actual displacement of the valve core. = 0.01 mm, displacement deviation No deviation correction is needed. The next instruction will still be 0.0103mm.

[0048] Furthermore, the current filtered pressure difference (0.051MPa) < ΔP2(0.5MPa), the backup channel maintains its initial opening. , without taking any action.

[0049] At the end of one cycle: the system issues a positive displacement command of 0.0103 mm, causing the valve core to move towards the direction of increasing the compensation orifice, allowing hydraulic oil to flow in to balance the internal and external pressures. Since the current pressure difference (0.051 MPa) is less than the shallow sea sensitivity threshold ΔP1 (0.0867 MPa), the next cycle... The controller's integral term will continue to accumulate slowly, fine-tuning the valve spool position until the pressure differential approaches zero.

[0050] Example (2): Step 1: The data acquisition unit first collects the external seawater pressure. Through formula Calculate the original pressure difference inside and outside the device.

[0051] Diving depth: H = 8000 m (deeper than 3000 m) External seawater pressure: ≈80MPa (Approximate calculation: 10m water depth ≈ 0.1MPa) Internal hydraulic oil pressure: =79.5MPa (a slight negative pressure difference exists in the initial state) Initial pressure difference: ΔP =|80–79.5| = 0.5 MPa Step 2: The data filtering unit uses moving average filtering and Kalman wave filtering to analyze the acquired pressure difference. Purification and interference elimination are performed. Pressure difference calculation and filtering assume the original pressure differences from five consecutive samples are: [0.5, 0.51, 0.49, 0.52, 0.48] MPa. Furthermore, we first employ a moving average filter:

[0052] =(0.5+0.51+0.49+0.52+0.48) / 5=0.5MPa Furthermore, Kalman waves are used as a supplement to the moving average filter to further reduce random noise and provide more accurate state estimation. Assume the filtering result at the previous time step... =0.49MPa, combined with default noise Through formula + Predict the current pressure differential state and finally obtain the filtered pressure differential.

[0053] Step 3: The data processing unit provides control strategies for the displacement and execution speed of the corresponding execution unit based on different depth ranges. Pressure direction determination: (80MPa) > (79.5MPa) → The area of ​​the compensation hole needs to be increased, and the valve core displacement is positive.

[0054] Furthermore, the threshold is adaptively corrected based on depth H. The data processing unit dynamically adjusts according to depth H, increasing sensitivity in shallow waters and maintaining stability in deep waters. Controller output: Proportional portion: 0.2 mm / MPa·0.498MPa = 0.0996 mm, Integral part: Assuming this is the first control cycle, the integral term accumulates from zero. = 0.1 mm / (MPa s)·0.498 MPa·0.01s ≈0.000498mm, control quantity Since H = 1000m < 3000m, the threshold ΔP1 is corrected as follows: Threshold ΔP2 correction: =0.5+0.1·(8000-3000) / 8000= 0.5+0.1·(5000 / 8000)=0.5+0.0625= 0.5625 MPa.

[0055] Step 4: After the execution unit executes the corresponding command, if there is a deviation between the valve core displacement and the commanded displacement, or if the differential pressure exceeds the limit after adjustment, compensation is required.

[0056] Furthermore, displacement deviation correction assumes the actual displacement of the valve core. =0.095mm (there is a certain deviation), displacement deviation No deviation correction is needed. The next instruction will still be 0.1001mm.

[0057] Furthermore, the current filtered pressure difference (0.498MPa) < ΔP2 (0.5625MPa), the backup channel maintains its initial opening. , without taking any action.

[0058] One cycle ends: the system issues a positive displacement command of 0.1001 mm. This displacement is much larger than in shallow sea conditions because the pressure difference is greater and Kp is constant. In deep sea conditions, ΔP1 remains at 0.1 MPa, meaning that stronger displacement will only occur when the pressure difference exceeds 0.1 MPa. This adjustment avoids frequent adjustments due to minor fluctuations under high pressure. The current pressure difference of 0.498 MPa is much greater than ΔP1. The controller will rapidly actuate the valve spool with a large output to quickly reduce the pressure differential. Subsequent cycle projection: Assuming that after several cycles of adjustment, the internal pressure rises and the pressure differential decreases to... =0.15MPa. The output u(t) = 0.2·0.15 + (accumulated integral term). The proportional component contributes 0.03 mm, slowing down the adjustment speed. At this point... =0.15MPa is still greater than ΔP1 (0.1 MPa). The system continues to work, with the integral term working to eliminate the steady-state error. Eventually, the system will stabilize the differential pressure at a level close to zero.

[0059] Through these two specific embodiments, it can be clearly seen that: The data processing unit is responsible for converting the differential pressure signal into a specific valve core displacement. The actuator lowers the adjustment threshold (ΔP1 decreases) and improves sensitivity in shallow waters; in deep waters, it raises the adjustment threshold (ΔP1 remains unchanged, ΔP2 increases), ensuring system stability. The data filtering unit is an important auxiliary means to improve control accuracy and system stability.

[0060] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A compensation mechanism for an underwater hydraulic system integrating filtration and adaptive pressure regulation, characterized in that, The system includes a data acquisition unit, a data filtering unit, a data processing unit, an execution unit, and a two-stage filtering module. These units are sequentially connected to form a closed loop. The two-stage filtering module is positioned along the path of the hydraulic oil entering the underwater working equipment. The data acquisition unit collects data on the equipment's diving depth, external seawater pressure, internal hydraulic oil pressure, and valve core displacement, and sends this data to the data filtering unit. The data filtering unit filters and selects the collected data to obtain the pressure difference data between the inside and outside of the equipment, and sends this data to the data processing unit. The data processing unit determines the depth range of the equipment based on the pressure difference data and provides corresponding displacement and execution speed control strategies for the execution unit. The execution unit receives the control strategy, executes the control commands, and simultaneously feeds back the actual valve core displacement to the data processing unit.

2. The compensation mechanism according to claim 1, characterized in that, The dual-stage filtration module includes a coarse filtration unit and a fine filtration unit arranged sequentially along the fluid flow direction; the coarse filtration unit is in the form of a sintered metal mesh with a pore size of 50-100μm; the surface of the fine filtration unit is coated with a nano-ceramic filter screen; the outer side of the coarse filtration unit is detachable for cleaning or replacement.

3. The compensation mechanism according to claim 1, characterized in that, The data filtering unit processes data using a combination of moving average filtering and Kalman filtering; the moving average filtering applies the raw pressure difference ΔP over n consecutive sampling periods. i Perform an arithmetic mean to obtain the smoothed average pressure difference. Based on the filtering results of the previous time step (k-1) and combined with default noise Through formula Predict the current pressure differential state; then calculate the Kalman gain. In establishing ,in The prediction error covariance is given by R, where R represents the measurement noise, and the actual measured values ​​are also considered. Establish formula Correcting the predicted values ​​yields the final filtered pressure difference. .

4. The compensation mechanism according to claim 1, characterized in that, The data processing unit establishes a pressure differential based on the principles of flow continuity and force balance of the hydraulic servo valve. The equation relating the valve core displacement S to the valve core displacement is shown in the following equation. Combining the flow rate formula in fluid mechanics ;in For flow coefficient, The flow area corresponding to the valve core displacement is linearly related to the displacement, approximately... , The density of the hydraulic oil, The pressure difference between the inside and outside of the valve body is used as the input quantity. Simplify the flow formula ,in The flow gain is a constant. Establish the mechanical equations of the execution unit based on Newton's second law. Where m is the total mass of the valve core and push rod, B is the viscous damping coefficient, and K is the spring stiffness. Let be the first derivative of the valve core displacement with respect to time. Let F be the second derivative of the valve core displacement with respect to time, and F be the driving force, which is balanced by the hydrodynamic force generated by the pressure difference and the motor driving force. Flow equation Substituting the equations of motion of the execution unit and linearizing them, we get... ,in Consider it as the rated pressure difference, and consider it as a constant; let Using the pressure difference to force conversion coefficient, the linearized time-domain equations of pressure difference and valve core displacement are obtained. ； Performing a Plas transform on the time-domain equation, the input... and Transforming from the time domain to the complex frequency domain, the transfer function of pressure difference-valve spool displacement is obtained as follows: This transfer function describes the dynamic influence characteristics of valve core displacement on differential pressure in the complex frequency domain. The dynamic response speed and accuracy of valve core displacement can be optimized by adjusting the controller parameters of the actuator unit.

5. The compensation mechanism according to claim 1, characterized in that, The data processing unit incorporates a PI controller and outputs... At the same time, a threshold adaptively corrected based on depth H is introduced. and The data processing unit dynamically adjusts according to depth H, increasing sensitivity in shallow waters and maintaining stability in deep waters. When H < 3000m, the shallow sea area is: When H > 3000m, the deep-sea range is: Keep the default values ​​and avoid over-adjustment; When H < 3000m, the shallow sea area is: Maintain default values ​​and respond quickly; When H > 3000m, the deep-sea range is: In the formula, 8000 represents the depth span of "3000m to 11000m".

6. The compensation mechanism according to claim 1, characterized in that, The valve core displacement control logic of the execution unit is as follows: when the external seawater pressure Pext > Pint, the external pressure is high and the area of ​​the compensation orifice needs to be increased, thus controlling the valve core displacement. ; When Pext < Pint, the internal pressure is high, and the area of ​​the compensation orifice needs to be reduced to control the valve core displacement. The negative sign indicates that the displacement direction is opposite. S is the displacement of the valve core relative to the initial position. Positive means "increasing area direction" and negative means "decreasing area direction".

7. The compensation mechanism according to claim 1, characterized in that, If the actual displacement of the valve core deviates from the commanded displacement after the execution unit executes the command, or if the differential pressure exceeds the limit after adjustment, compensation control is required. Establish a formula for correcting valve core displacement deviation. ; For command signals, This is the actual displacement. For deviation, Correction factor, if Then the corrected instruction shift, , =0.3, proportional correction, quickly reducing displacement deviation.

8. The compensation mechanism according to claim 1, characterized in that, If the differential pressure still exceeds the limit after adjustment, increase the opening of the backup channel. , This is the initial opening of the backup channel. To limit overpressure, the maximum opening cannot exceed 1.5 times the area of ​​the main channel.

9. The compensation mechanism according to any one of claims 1-8, characterized in that, The compensation mechanism is adapted to working conditions at depths of 0 to 11,000 meters and is suitable for the hydraulic control systems of deep-sea robots, seabed mining equipment, or deep-sea observation systems.

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