A high-frequency-response electro-hydraulic servo valve based on double closed-loop feedback

Abstract

The application discloses a high-frequency-response electro-hydraulic servo valve based on double closed-loop feedback, relates to the technical field of oil exploitation automation, and solves the problem of the decline of positioning accuracy of the sucker rod at the end of stroke caused by load change and running friction. The high-frequency-response electro-hydraulic servo valve based on double closed-loop feedback comprises a displacement sensor, a controller and a servo driver. The displacement sensor is used for collecting the running parameters of a hydraulic cylinder piston, and the running parameters are sent to the controller. The controller is used for calculating the running deviation of the hydraulic cylinder piston running to a target position according to the running parameters. The controller is also used for calculating the target thrust corresponding to the compensation of the running deviation, and after the target thrust is converted into a target current value, the target current value is fed back to the servo valve driver of the current loop as a target instruction. The servo valve driver drives the valve core of the electro-hydraulic servo valve to generate a target displacement with the target current value.

Description

Technical Field

[0001] This application relates to the field of oil extraction automation technology, and in particular to a high-frequency electro-hydraulic servo valve based on dual closed-loop feedback. Background Technology

[0002] Automated oil extraction refers to the deep integration of automatic control technology, sensor technology, computer technology, communication technology, and hydraulic and mechanical execution technology, applied to all aspects of oil extraction (such as drilling, oil production, gathering and transportation) to achieve less or no human intervention, precise control, and intelligent decision-making in the extraction process.

[0003] In the field of automated oil extraction, hydraulic pumping units are used to continuously lift crude oil from underground reservoirs to the surface wellhead via tubing. A hydraulic pumping unit includes a controller, sucker rod, and downhole pump. The controller receives operator-issued commands, including stroke length and number of cycles per unit time. Based on these commands, it generates a motion curve for the sucker rod. This motion curve defines the target position, velocity, and acceleration of the sucker rod at each moment of movement. By controlling the sucker rod to follow the motion curve, rigid impacts such as piston-cylinder collisions are avoided, ensuring the safe operation of the sucker rod string and downhole pump within their designed geometric stroke, while simultaneously guaranteeing the continuous and efficient lifting of crude oil.

[0004] During equipment operation, the load on the sucker rod string exhibits dynamic nonlinearity due to various time-varying factors, including changes in the dynamic fluid level of the oil well, alterations in crude oil properties, fluctuations in downhole frictional resistance, and system leakage. Under the continuous influence of such complex disturbances, even if the controller initially presets an ideal motion curve, the actual operating trajectory of the system will gradually deviate from the target value, leading to a decrease in the positioning accuracy of the sucker rod at the end of its stroke. Summary of the Invention

[0005] In view of this, this application provides a high-frequency electro-hydraulic servo valve based on dual closed-loop feedback to solve the problem of decreased positioning accuracy of the sucker rod at the end of its stroke caused by load changes and operating friction.

[0006] This application provides a high-frequency electro-hydraulic servo valve based on dual closed-loop feedback, the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback includes: a displacement sensor, a controller, and a servo driver;

[0007] The displacement sensor is used to collect the operating parameters of the hydraulic cylinder piston and send the operating parameters to the controller;

[0008] The controller is used to calculate the operating deviation of the hydraulic cylinder piston from the target position based on the operating parameters;

[0009] The controller is also used to calculate the target thrust corresponding to compensate for the operating deviation, and after converting the target thrust into a target current value, feeds the target current value back to the servo valve driver of the current loop as a target command;

[0010] The servo valve driver drives the valve core of the electro-hydraulic servo valve to generate the target displacement with the target current value.

[0011] In one implementation, the controller is further configured to calculate a feedforward compensation force based on the ideal acceleration, and update the target thrust based on the feedforward compensation force.

[0012] In one possible implementation, the servo valve driver incorporates a built-in current sampling circuit;

[0013] The servo valve driver collects the actual current of the torque motor coil through a current sampling circuit, compares the actual current with the target current value, and adjusts the parameters of the servo valve driver while driving the electro-hydraulic servo valve with the target current value based on the comparison result.

[0014] In one possible implementation, the process of the servo valve driver dynamically adjusting the power output to the torque motor coil based on a comparison result to drive valve spool displacement includes:

[0015] When the actual current is less than the target current value, the servo valve driver increases the duty cycle of the PWM control signal;

[0016] When the actual current is greater than the target current value, the servo valve driver reduces the duty cycle of the PWM control signal.

[0017] In one implementation, a current comparison unit is set in the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback. The current comparison unit includes an error amplifier and a PWM comparator.

[0018] The inverting input of the error amplifier is connected to the current sampling circuit, and the inverting input of the error amplifier is connected to the controller.

[0019] The error amplifier is used to compare the actual current output by the current sampling circuit with the target current value input by the controller, and outputs a voltage signal representing the deviation between the actual current and the target current value.

[0020] The COMP pin of the error amplifier is connected to the non-inverting input of the PWM comparator, and the inverting input of the PWM comparator is connected to the oscillator to receive the high-frequency sawtooth wave signal input from the oscillator. Based on the comparison result between the high-frequency sawtooth wave signal and the voltage signal, the corresponding level signal is output.

[0021] In one implementation, the current comparison unit further includes a feedback network; the feedback network is connected across the inverting input of the error amplifier and the COMP pin; the feedback network includes a feedback resistor and a feedback capacitor;

[0022] The feedback resistor is used to adjust the amplification factor of the error amplifier for voltage deviation;

[0023] Feedback capacitors are used to filter out high-frequency noise.

[0024] In one possible implementation, the displacement sensor is further configured to acquire a reference measurement value of the hydraulic cylinder piston when the hydraulic cylinder piston is at a preset reference position, and send the reference measurement value to the controller;

[0025] The controller is also used to perform zero-point correction on the operating parameters based on the reference measurement value to obtain the corrected operating parameters;

[0026] The controller is specifically used to calculate the operating deviation based on the corrected operating parameters.

[0027] In one possible implementation, a temperature sensor is provided at an adjacent position of the displacement sensor to collect the temperature value of the environment in which the displacement sensor is located and send the temperature value to the controller.

[0028] The controller is also used to query a pre-stored temperature drift compensation curve based on the temperature value and obtain the temperature drift compensation amount corresponding to the temperature value;

[0029] The controller is specifically used to correct the operating parameters based on the zero-point offset error and the temperature drift compensation.

[0030] In one possible implementation, a signal conditioning circuit is provided between the displacement sensor and the controller;

[0031] The signal conditioning circuit includes a filtering unit, which is used to filter the original signal output by the displacement sensor to remove high-frequency noise components in the original signal, and send the filtered signal to the controller as the operating parameter.

[0032] In one possible implementation, the controller further includes a built-in digital filtering module;

[0033] The digital filtering module is used to execute a pre-set digital filtering algorithm on the received operating parameters. The digital filtering algorithm includes at least one of the following: amplitude limiting filtering algorithm, moving average filtering algorithm, median filtering algorithm, and Kalman filtering algorithm.

[0034] The controller is specifically used to calculate the operating deviation based on the operating parameters processed by the digital filtering module.

[0035] Compared to existing technologies, this application proposes a high-frequency response electro-hydraulic servo valve based on dual closed-loop feedback. The outer ring of this electro-hydraulic servo valve uses a displacement sensor to monitor the position and speed parameters of the hydraulic pumping unit in real time during operation. This data is compared with a preset motion target curve to calculate the position and speed deviations of the hydraulic cylinder piston from the target position. Based on these deviations, a control algorithm calculates the target thrust required to compensate for the deviations and converts this target thrust into a corresponding current command value, which is then sent to the servo valve driver in the inner ring. The servo valve driver in the inner ring, based on the current command value, drives the valve core of the electro-hydraulic servo valve to displace, adjusting the flow rate and direction of the oil entering the hydraulic cylinder, and outputting the thrust required to compensate for the deviations. This ensures that the sucker rod can accurately reach the target position even under actual load disturbances, guaranteeing the efficient and safe operation of the pumping unit. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1 This is a schematic diagram showing the component position relationship of the high-frequency response electro-hydraulic servo valve based on dual closed-loop feedback proposed in the embodiments of this application;

[0038] Figure 2 This is a schematic diagram of a current comparison unit provided in one example of this application;

[0039] Figure 3 This is a schematic diagram of a current comparison unit as given in another example of this application. Detailed Implementation

[0040] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0041] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0042] In view of the problems raised in the background technology, this application proposes a high-frequency response electro-hydraulic servo valve based on dual closed-loop feedback. The outer ring of this electro-hydraulic servo valve uses a displacement sensor to monitor the position and speed parameters of the hydraulic pumping unit in real time during operation. This data is compared with a preset motion target curve to calculate the position and speed deviations of the hydraulic cylinder piston from the target position. Based on these deviations, a control algorithm calculates the target thrust required to compensate for the deviations and converts this target thrust into a corresponding current command value, which is then sent to the servo valve driver in the inner ring. The servo valve driver in the inner ring, based on the current command value, drives the valve core of the electro-hydraulic servo valve to generate displacement, adjusting the flow rate and direction of the oil entering the hydraulic cylinder, and outputting the thrust required to compensate for the deviations. This ensures that the sucker rod can still accurately move to the target position under actual load disturbances, guaranteeing the efficient and safe operation of the pumping unit.

[0043] The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in this application includes: a displacement sensor, a controller, and a servo driver.

[0044] Figure 1 This is a schematic diagram showing the component positional relationship of the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in the embodiments of this application, as shown below. Figure 1 As shown, displacement sensor 1 and controller 2 form an outer loop feedback device. Displacement sensor 1 is installed on hydraulic cylinder piston 5 to collect the operating parameters of hydraulic cylinder piston 5 and send the operating parameters to controller 3. Controller 3 and servo driver 4 form an inner loop feedback device. Controller 3 generates instructions based on the operating parameters and sends them to servo driver 4. Servo driver 4 responds to the instructions and drives electro-hydraulic servo valve 5 to move according to the parameters corresponding to the instructions. Servo driver 4 is electrically connected to electro-hydraulic servo valve 5. The movement of the valve core of electro-hydraulic servo valve 5 drives high-pressure oil to rush into the hydraulic cylinder along the oil pipe, thereby driving hydraulic cylinder piston 6 to move.

[0045] The displacement sensor is used to collect the operating parameters of the hydraulic cylinder piston and send the operating parameters to the controller; the controller is used to calculate the operating deviation of the hydraulic cylinder piston when it reaches the target position based on the operating parameters.

[0046] The controller is also used to calculate the target thrust corresponding to compensate for the operating deviation, and after converting the target thrust into a target current value, feeds the target current value back to the servo valve driver of the current loop as a target command;

[0047] The servo valve driver drives the valve core of the electro-hydraulic servo valve to generate the target displacement with the target current value.

[0048] The hydraulic cylinder piston is rigidly connected to the top of the sucker rod, driving the sucker rod to move. When the hydraulic cylinder piston moves upward, it drives the sucker rod upward, lifting the crude oil in the underground pump barrel to the surface gathering and transportation system. After being processed by equipment such as metering stations and combined stations, it finally enters the oil storage tank for storage and external transportation. When the hydraulic cylinder piston moves downward, it drives the sucker rod downward, collecting the crude oil in the well into the pump barrel of the oil pump, preparing for the next lift.

[0049] Operating parameters include the position and speed of the hydraulic cylinder piston.

[0050] Operational deviations include positional deviations and speed deviations.

[0051] For example, assuming that based on the ideal motion curve S, the ideal velocity of the hydraulic cylinder piston at time t is... The ideal location is The hydraulic cylinder piston moves After a certain time, the actual location is collected in real time. and speed Calculate the running deviation Δ of the hydraulic cylinder piston when it reaches the target position. - (3), Δ = (2).

[0052] Continuing with the example above, using speed loop PID control, the feedback correction thrust is calculated using the following formula (3). = + (3), where, Indicates the deviation Δ of the current speed The instantaneous response coefficient, The response coefficient represents the cumulative amount of velocity deviation at historical moments. The coefficient representing the response to changes in speed deviation. , , It can be obtained through prior experimental calibration.

[0053] Target thrust (4), The real-time load force is measured by a pressure sensor.

[0054] The controller retrieves the characteristic curve of the servo valve from its local storage. This characteristic curve is a flow-current curve obtained through pre-experimental calibration. The target current value corresponding to the target thrust is then retrieved from the characteristic curve. , (5); among which, For valve core zero-point offset compensation current, This refers to the gain coefficient of the servo valve, which is obtained from the factory calibration of the servo valve. = , This indicates the effective area on which the pressurized oil acts on the piston.

[0055] The target displacement is the displacement of the hydraulic cylinder piston driven by the target thrust after the oil is output.

[0056] Since the target current value is calculated from the target thrust that can compensate for the deviation of the operating position of the pumping mechanism, the pumping mechanism includes a hydraulic cylinder and a sucker rod. The servo valve driver drives the valve core of the electro-hydraulic servo valve to generate displacement and adjust the oil flow accordingly according to the target current value, so that the sucker rod can be driven to run accurately to the target position.

[0057] To counteract the feedback delay caused by inertia, load losses and friction losses persist during the movement of the sucker rod and hydraulic cylinder piston. Therefore, in this embodiment, the feedforward compensation force for time t+1 is calculated in advance at time t using feedforward calculation before the operational deviation occurs. The main thrust is output in advance before the acceleration or deceleration caused by load changes at time t+1, avoiding the lag in the feedback loop of "reacting only after the deviation occurs."

[0058] In the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in this application embodiment, the controller is also used to calculate the feedforward compensation force according to the ideal acceleration, and update the target thrust according to the feedforward compensation force.

[0059] In another example of this application, the feedforward compensation force is calculated. (6); To find the ideal motion curve S The acceleration corresponding to each moment, It represents the total equivalent kinematic mass converted to the piston rod of the hydraulic cylinder, that is, the total inertial mass of all moving parts required to push the piston of the hydraulic cylinder.

[0060] The target thrust is updated based on the feedforward compensation force.

[0061] The working principle of the servo valve driver can be represented as follows: the torque motor coil drives the armature baffle to produce a slight deflection, which establishes a pressure difference at both ends of the valve core, and this pressure difference drives the main valve core to move; after the main valve core moves, the high-pressure oil circuit is opened, driving the hydraulic cylinder piston to move.

[0062] Further investigation revealed that components within the servo valve driver heat up during outdoor high temperatures or continuous operation, increasing coil resistance. The increase in voltage causes fluctuations in the actual current. If the voltage is directly adjusted to drive the electro-hydraulic servo valve according to the target current value, the coil may not actually reach the target current value, resulting in a current deviation. This causes a decrease in electromagnetic force, and the thrust is insufficient to drive the valve core to produce the target displacement. In view of this, the embodiments of this application also propose a specific process for the servo valve driver to perform "driving the valve core of the electro-hydraulic servo valve to produce the target displacement with the target current value".

[0063] In view of this, in the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in the embodiments of this application, the servo valve driver has a built-in current sampling circuit;

[0064] The servo valve driver collects the actual current of the torque motor coil through a current sampling circuit, compares the actual current with the target current value, and adjusts the parameters of the servo valve driver while driving the electro-hydraulic servo valve with the target current value based on the comparison result.

[0065] The process by which the servo valve driver dynamically adjusts the power output to the torque motor coil based on the comparison result to drive the valve spool displacement includes:

[0066] When the actual current is less than the target current value, the servo valve driver increases the duty cycle of the PWM control signal;

[0067] When the actual current is greater than the target current value, the servo valve driver reduces the duty cycle of the PWM control signal.

[0068] The servo valve driver increases the duty cycle of the PWM control signal to increase the actual effective voltage applied across the torque motor coil; conversely, the servo valve driver increases the duty cycle of the PWM control signal to decrease the actual effective voltage applied across the torque motor coil.

[0069] The duty cycle of a PWM control signal refers to the proportion of the high-level conduction time within a fixed switching cycle to the total duration of the switching cycle.

[0070] This application's embodiments are based on the objective fact that increased resistance due to heat leads to decreased current. According to the relationship between the actual current and the target current value, when the resistance increases, the duty cycle of the PWM control signal is adjusted to raise the voltage, thereby increasing the real-time current of the torque motor coil to reach the target current value. When the resistance decreases, the duty cycle of the PWM control signal is adjusted to lower the voltage, thereby reducing the real-time current of the torque motor coil to the target current value. This solves the problem of component overheating and coil resistance issues within the servo valve driver. The increase in current causes fluctuations in the actual current, resulting in a decrease in electromagnetic force and insufficient thrust to drive the valve core to produce the target displacement.

[0071] To further simplify and efficiently implement the above process, this application proposes a current comparison unit that compares the actual current with the target current value, and performs the following steps: when the actual current is less than the target current value, the servo valve driver increases the duty cycle of the PWM control signal; when the actual current is greater than the target current value, the servo valve driver decreases the duty cycle of the PWM control signal.

[0072] A current comparison unit is set in a high-frequency electro-hydraulic servo valve based on dual closed-loop feedback. The current comparison unit includes an error amplifier and a PWM comparator.

[0073] The inverting input of the error amplifier is connected to the current sampling circuit, and the inverting input of the error amplifier is connected to the controller.

[0074] The error amplifier is used to compare the actual current output by the current sampling circuit with the target current value input by the controller, and outputs a voltage signal representing the deviation between the actual current and the target current value.

[0075] The COMP pin of the error amplifier is connected to the non-inverting input of the PWM comparator, and the inverting input of the PWM comparator is connected to the oscillator to receive the high-frequency sawtooth wave signal input from the oscillator. Based on the comparison result between the high-frequency sawtooth wave signal and the voltage signal, the corresponding level signal is output.

[0076] The current sampling circuit can be composed of a sampling resistor and an isolation amplifier to collect the actual current of the torque motor coil.

[0077] Figure 2 This is a schematic diagram of a current comparison unit provided in one example of this application, such as... Figure 2 As shown, the inverting input of the error amplifier is connected to the current sampling circuit, receiving the actual current output by the current sampling circuit. Yes, by connecting a sampling resistor in series in the current loop, the actual current is... Converted to first equivalent voltage The inverting input of the error amplifier is connected to the controller to receive the target current value input from the controller. Similarly, it is converted into a second equivalent voltage through a series sampling resistor circuit. .

[0078] Isolation amplifier comparison and Operational amplifiers achieve this through the physical connections of the components themselves. and The voltage deviation ΔV is obtained by differential calculation, ΔV= - When ΔV > 0, the output voltage of the COMP pin of the error amplifier increases based on the characteristics of the transistor; when ΔV < 0, the output voltage of the COMP pin of the error amplifier decreases.

[0079] The non-inverting input of the PWM comparator receives the output voltage of the error amplifier, while the inverting input receives the sawtooth wave signal from the oscillator. The sawtooth wave signal rises from a low level to its peak and then falls back, constituting one cycle. During each cycle, the PWM comparator compares the output voltage with the sawtooth wave voltage in real time. If the output voltage > the sawtooth wave voltage, the PWM comparator outputs a high level at its OUT terminal; if the output voltage < the sawtooth wave voltage, the PWM comparator outputs a low level at its OUT terminal. A longer high-level duration results in a larger PWM duty cycle, thus increasing the duty cycle of the PWM control signal. Increasing the duty cycle of the PWM control signal, in turn, decreases the duty cycle of the PWM control signal.

[0080] Furthermore, the current comparison unit also includes a feedback network; the feedback network is connected across the inverting input of the error amplifier and the COMP pin; the feedback network includes a feedback resistor and a feedback capacitor;

[0081] The feedback resistor is used to adjust the amplification factor of the error amplifier for voltage deviation;

[0082] Feedback capacitors are used to filter out high-frequency noise.

[0083] Figure 3 This is a schematic diagram of another example of a current comparison unit provided in this application, such as... Figure 3 As shown, the feedback resistor With feedback capacitor in parallel, Used to determine the amplification factor of the error amplifier for the deviation. Filter out high-frequency noise to prevent the current loop from oscillating or self-exciting, and ensure the stable operation of the current loop.

[0084] In the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in this application embodiment, the displacement sensor is also used to collect the reference measurement value of the hydraulic cylinder piston when the hydraulic cylinder piston is at a preset reference position, and send the reference measurement value to the controller;

[0085] The controller is also used to perform zero-point correction on the operating parameters based on the reference measurement value to obtain the corrected operating parameters;

[0086] The controller is specifically used to calculate the operating deviation based on the corrected operating parameters.

[0087] Continuing with the example above, let's assume that the actual location is collected in real time. The baseline measurement value is For actual location Perform zero-point calibration to obtain the corrected actual position. = - .

[0088] This application embodiment introduces a zero-point self-calibration function, which can effectively eliminate zero-point drift of the displacement sensor caused by long-term use, mechanical vibration or temperature changes, and ensure the accuracy of the collected piston position data, thereby improving the control accuracy of the entire dual closed-loop feedback system.

[0089] Furthermore, in the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in this application embodiment, a temperature sensor is provided at the adjacent position of the displacement sensor to collect the temperature value of the environment where the displacement sensor is located and send the temperature value to the controller.

[0090] The controller is also used to query a pre-stored temperature drift compensation curve based on the temperature value and obtain the temperature drift compensation amount corresponding to the temperature value;

[0091] The controller is specifically used to correct the operating parameters based on the zero-point offset error and the temperature drift compensation.

[0092] This application embodiment includes a temperature sensor to monitor the ambient temperature. To address the issue of measurement errors caused by temperature variations in the sound velocity of the waveguide wire in magnetostrictive displacement sensors, a built-in temperature compensation mechanism can significantly suppress the impact of outdoor temperature differences on measurement accuracy, ensuring the stability and reliability of the system under all-weather operating conditions.

[0093] In one example, the temperature drift compensation curve of the displacement sensor is calibrated experimentally. For instance, by consulting the temperature drift compensation curve, it is found that at a reference point of 25℃, for every 1℃ change in temperature, the displacement sensor reading shifts by 0.002mm. Therefore, when the temperature sensor detects an ambient temperature of T℃, the temperature drift compensation is confirmed to be (T-25)×0.002mm, representing the actual position measured by the displacement sensor. Correct the actual position .

[0094] Furthermore, in the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in this application embodiment, a signal conditioning circuit is provided between the displacement sensor and the controller; the signal conditioning circuit includes a filtering unit, which is used to filter the original signal output by the displacement sensor to remove high-frequency noise components in the original signal, and send the filtered signal to the controller as the operating parameter.

[0095] By adding a hardware filtering circuit at the signal input end, high-frequency noise coupled to the sensor signal during transmission can be effectively filtered out, preventing noise signals from entering the controller and causing distortion in differential terms, such as speed deviation calculations, thus improving the system's anti-interference capability and operational stability in harsh electromagnetic environments.

[0096] Furthermore, in the high-frequency electro-hydraulic servo valve based on dual closed-loop feedback proposed in the embodiments of this application,

[0097] The controller also has a built-in digital filtering module;

[0098] The digital filtering module is used to execute a pre-set digital filtering algorithm on the received operating parameters. The digital filtering algorithm includes at least one of the following: amplitude limiting filtering algorithm, moving average filtering algorithm, median filtering algorithm, and Kalman filtering algorithm.

[0099] The controller is specifically used to calculate the operating deviation based on the operating parameters processed by the digital filtering module.

[0100] Building upon hardware filtering, further smoothing of the signal through digital filtering can more effectively suppress periodic interference and impulse noise. In particular, algorithms such as Kalman filtering can maintain the dynamic response characteristics of the signal while filtering out noise, providing higher quality position and velocity feedback signals for dual closed-loop feedback systems.

[0101] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computing software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0102] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0103] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A high-frequency electro-hydraulic servo valve based on dual closed-loop feedback, characterized in that, The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback includes: a displacement sensor, a controller, and a servo driver; The displacement sensor is used to collect the operating parameters of the hydraulic cylinder piston and send the operating parameters to the controller; The controller is used to calculate the operating deviation of the hydraulic cylinder piston from the target position based on the operating parameters; The controller is also used to calculate the target thrust corresponding to compensate for the operating deviation, and after converting the target thrust into a target current value, feeds the target current value back to the servo valve driver of the current loop as a target command; The servo valve driver drives the valve core of the electro-hydraulic servo valve to generate the target displacement with the target current value.

2. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, The controller is also used to calculate the feedforward compensation force based on the ideal acceleration, and update the target thrust based on the feedforward compensation force.

3. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, The servo valve driver has a built-in current sampling circuit. The servo valve driver collects the actual current of the torque motor coil through a current sampling circuit, compares the actual current with the target current value, and adjusts the parameters of the servo valve driver while driving the electro-hydraulic servo valve with the target current value based on the comparison result.

4. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 3, characterized in that, The process by which the servo valve driver dynamically adjusts the power output to the torque motor coil based on the comparison result to drive the valve spool displacement includes: When the actual current is less than the target current value, the servo valve driver increases the duty cycle of the PWM control signal; When the actual current is greater than the target current value, the servo valve driver reduces the duty cycle of the PWM control signal.

5. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 4, characterized in that, A current comparison unit is set in a high-frequency electro-hydraulic servo valve based on dual closed-loop feedback. The current comparison unit includes an error amplifier and a PWM comparator. The inverting input of the error amplifier is connected to the current sampling circuit, and the inverting input of the error amplifier is connected to the controller. The error amplifier is used to compare the actual current output by the current sampling circuit with the target current value input by the controller, and outputs a voltage signal representing the deviation between the actual current and the target current value. The COMP pin of the error amplifier is connected to the non-inverting input of the PWM comparator, and the inverting input of the PWM comparator is connected to the oscillator to receive the high-frequency sawtooth wave signal input from the oscillator. Based on the comparison result between the high-frequency sawtooth wave signal and the voltage signal, the corresponding level signal is output.

6. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 5, characterized in that, The current comparison unit also includes a feedback network; the feedback network is connected across the inverting input of the error amplifier and the COMP pin; the feedback network includes a feedback resistor and a feedback capacitor; The feedback resistor is used to adjust the amplification factor of the error amplifier for voltage deviation; Feedback capacitors are used to filter out high-frequency noise.

7. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, The displacement sensor is also used to collect a reference measurement value of the hydraulic cylinder piston when the hydraulic cylinder piston is at a preset reference position, and send the reference measurement value to the controller; The controller is also used to perform zero-point correction on the operating parameters based on the reference measurement value to obtain the corrected operating parameters; The controller is specifically used to calculate the operating deviation based on the corrected operating parameters.

8. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, A temperature sensor is installed at an adjacent position of the displacement sensor to collect the temperature value of the environment in which the displacement sensor is located and send the temperature value to the controller. The controller is also used to query a pre-stored temperature drift compensation curve based on the temperature value and obtain the temperature drift compensation amount corresponding to the temperature value; The controller is specifically used to correct the operating parameters based on the zero-point offset error and the temperature drift compensation.

9. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, A signal conditioning circuit is provided between the displacement sensor and the controller; The signal conditioning circuit includes a filtering unit, which is used to filter the original signal output by the displacement sensor to remove high-frequency noise components in the original signal, and send the filtered signal to the controller as the operating parameter.

10. The high-frequency electro-hydraulic servo valve based on dual closed-loop feedback according to claim 1, characterized in that, The controller also has a built-in digital filtering module; The digital filtering module is used to execute a pre-set digital filtering algorithm on the received operating parameters. The digital filtering algorithm includes at least one of the following: amplitude limiting filtering algorithm, moving average filtering algorithm, median filtering algorithm, and Kalman filtering algorithm. The controller is specifically used to calculate the operating deviation based on the operating parameters processed by the digital filtering module.

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