A constant force maintaining method and device for polishing the inner wall of a hydraulic cylinder barrel

Abstract

This application discloses a constant force maintenance method and apparatus for polishing the inner wall of a hydraulic cylinder, relating to the field of hydraulic cylinder technology. The method includes: acquiring pressure and flow data sequences from the pump station, real-time flow rate of the hydraulic hose, and real-time rotational speed of the polishing head during the polishing operation; calculating instantaneous flow resistance characteristic values ​​based on the pressure and flow data sequences; determining a viscosity correction coefficient based on the ratio between the instantaneous flow resistance characteristic value and a preset pipeline impedance reference; calculating the pipeline friction loss value based on the real-time flow rate, the preset pipeline impedance reference, and the viscosity correction coefficient, and calculating a centrifugal pressure compensation value based on the real-time rotational speed and a preset structural constant; and combining the preset process target pressure value, the pipeline friction loss value, and the centrifugal pressure compensation value to generate a pump station output pressure command to drive the pump station to maintain constant force output. This application can stably maintain the contact pressure of the polishing head.

Description

Technical Field

[0001] This application relates to the field of hydraulic cylinder technology, specifically to a constant force maintenance method and apparatus for polishing the inner wall of a hydraulic cylinder barrel. Background Technology

[0002] In the polishing process of the inner wall of a deep-hole hydraulic cylinder, a long hydraulic hose is typically used to drive a hydraulically expandable polishing head deep into the hole. To ensure consistent processing, the polishing head must apply a constant contact pressure to the cylinder wall. Existing control methods often use constant pressure oil supply at the pump station, which makes it difficult to detect and compensate for changes in end pressure. The main technical problems are as follows: First, as the polishing head penetrates deeper, the flow resistance along the long hose changes with its length, leading to pressure attenuation; second, the increase in hydraulic oil temperature causes a decrease in viscosity, resulting in thermal drift of the flow resistance characteristics; finally, the centrifugal force generated by the high-speed rotation of the polishing head generates additional radial pressure at the end. Due to the limited space inside the deep hole, it is difficult to install sensors to directly measure the end pressure, making it impossible to stably maintain the contact pressure of the polishing head. Summary of the Invention

[0003] In order to solve the technical problem in related technologies that use constant pressure oil supply at the pump station end, it is difficult to sense and compensate for changes in end pressure, and thus cannot stably maintain the contact pressure of the polishing head, this application provides a constant force maintenance method and device for polishing the inner wall of a hydraulic cylinder.

[0004] The specific technical solution adopted is as follows: Acquire pressure and flow data sequences at the pump station end, real-time flow of hydraulic hoses, and real-time rotational speed of the polishing head during the polishing operation; Calculate the current instantaneous flow resistance characteristic value based on the pressure data sequence and the flow rate data sequence; The viscosity correction factor is determined based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance reference. Based on real-time flow rate, preset pipeline impedance reference and viscosity correction coefficient, the pressure loss along the pipeline is calculated, and based on real-time rotation speed and preset structural constant, the centrifugal pressure compensation value caused by rotation is calculated. The preset process target pressure value, pipeline friction loss value, and centrifugal pressure compensation value are combined to generate the pump station output pressure command to drive the pump station to maintain constant force output.

[0005] In one possible implementation of this application, the instantaneous flow resistance characteristic value is calculated based on the pressure data sequence and the flow rate data sequence, including: Based on the similarity between the pressure data sequence and the flow data sequence, time-series alignment processing is performed on the pressure data sequence and the flow data sequence; Based on the aligned pressure and flow data sequences, the current instantaneous flow resistance characteristic value is calculated.

[0006] In one possible implementation of this application, time-series alignment processing is performed on the pressure data sequence and the flow data sequence based on the similarity between them, including: The transmission lag time is determined based on the maximum value of the cross-correlation function between the pressure data sequence and the flow data sequence. The calculation result of the cross-correlation function is used to characterize the similarity between the pressure data sequence and the flow data sequence at different time shifts. Based on the transmission lag time, time-series compensation is performed on the traffic data sequence to obtain the time-series compensated first data sequence. The first data sequence is paired with the pressure data sequence to align the timing of the pressure data sequence with that of the flow data sequence.

[0007] In one possible implementation of this application, the current instantaneous flow resistance characteristic value is calculated based on the aligned pressure data sequence and flow data sequence, including: Determine the first data pair consisting of the aligned pressure data sequence and the flow data sequence; Linear regression calculations are performed on each first data pair to obtain instantaneous flow resistance characteristic values, which are used to characterize the pressure change caused by a unit flow rate change.

[0008] In one possible embodiment of this application, before determining the viscosity correction factor based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance reference, the method further includes: The pipeline extension depth and the real-time pressure value at the pump station outlet are obtained during the process of the polishing head moving from the starting point to the bottom of the cylinder bore. Based on the ratio between the real-time pressure value and the preset calibrated flow rate, the preset pipeline impedance reference is calculated for different pipeline extension depths.

[0009] In one possible embodiment of this application, after determining the viscosity correction coefficient based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance reference, the method further includes: Determine the degree of linear correlation between the aligned pressure data sequence and the flow data sequence; Based on the degree of linear correlation, the viscosity correction coefficient is recursively updated.

[0010] In one possible implementation of this application, the pressure loss along the pipeline is calculated based on real-time flow rate, a preset pipeline impedance reference, and a viscosity correction factor, including: The actual transmission impedance value is calculated based on the preset pipeline impedance reference and viscosity correction coefficient. The pressure loss along the pipeline is calculated based on the product of the actual transmission impedance value and the real-time flow rate.

[0011] In one possible implementation of this application, the centrifugal pressure compensation value generated by rotation is calculated based on the real-time rotational speed and a preset structural constant, including: The centrifugal pressure compensation value generated by rotation is calculated based on the product of real-time rotation speed, preset structural constant, and preset hydraulic oil density.

[0012] In one possible implementation of this application, a pump station output pressure command is generated by combining a preset process target pressure value, a pipeline friction loss value, and a centrifugal pressure compensation value, including: The preset process target pressure value is superimposed with the pipeline friction loss value to obtain the superimposed pressure value; The superimposed pressure value is subtracted from the centrifugal pressure compensation value to obtain the pump station output pressure value, and the corresponding pump station output pressure command is generated.

[0013] This application also provides a constant force maintaining device for polishing the inner wall of a hydraulic cylinder barrel. The device includes: a memory, a processor, and a constant force maintaining program for polishing the inner wall of a hydraulic cylinder barrel stored in the memory and executable on the processor. The constant force maintaining program for polishing the inner wall of a hydraulic cylinder barrel is configured to implement the steps of the constant force maintaining method for polishing the inner wall of a hydraulic cylinder barrel as described above.

[0014] This application has, but is not limited to, the following technical effects: In this application, by acquiring the pressure and flow data sequences of the pump station, the real-time flow rate of the hydraulic hose, and the real-time rotation speed of the polishing head during the polishing operation, and then calculating the current instantaneous flow resistance characteristic value based on the pressure and flow data sequences, the viscosity correction coefficient is determined based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance benchmark. By establishing a spatial static benchmark and combining it with online viscosity correction, the system can not only compensate for the pressure drop caused by the change in pipe length, but also correct the viscosity drift caused by the increase in oil temperature in real time, ensuring the consistency of processing pressure throughout the entire stroke. Based on real-time flow rate, preset pipeline impedance reference, and viscosity correction coefficient, the pipeline friction loss value is calculated. Based on real-time rotation speed and preset structural constant, the centrifugal pressure compensation value generated by rotation is calculated. The preset process target pressure value, pipeline friction loss value, and centrifugal pressure compensation value are combined to generate the pump station output pressure command. Through an independent centrifugal pressure compensation mechanism, the centrifugal pressure component caused by rotation speed is actively deducted when generating the oil supply command, which effectively prevents over-cutting of the workpiece inner wall caused by the surge of end contact force during high-speed operation. Thus, the contact pressure of the polishing head is stably maintained without installing sensors to directly measure the end pressure. Attached Figure Description

[0015] Figure 1 This is a schematic flowchart of the first embodiment of the constant force maintenance method for polishing the inner wall of a hydraulic cylinder barrel according to this application; Figure 2 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application. Detailed Implementation

[0016] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0017] This application provides a constant force maintenance method for polishing the inner wall of a hydraulic cylinder. In the first embodiment of this application's constant force maintenance method for polishing the inner wall of a hydraulic cylinder, refer to... Figure 1 The methods include: Step S10: Obtain the pressure data sequence and flow data sequence at the pump station end, the real-time flow of the hydraulic hose, and the real-time rotation speed of the polishing head during the polishing operation.

[0018] As an example, the constant force maintaining method for polishing the inner wall of a hydraulic cylinder can be applied to a constant force maintaining device for polishing the inner wall of a hydraulic cylinder. The constant force maintaining device for polishing the inner wall of a hydraulic cylinder belongs to a constant force maintaining system for polishing the inner wall of a hydraulic cylinder, and the constant force maintaining system for polishing the inner wall of a hydraulic cylinder belongs to a constant force maintaining equipment for polishing the inner wall of a hydraulic cylinder.

[0019] As an example, the constant force maintenance method for polishing the inner wall of a hydraulic cylinder can also be applied to a constant force maintenance device for polishing the inner wall of a hydraulic cylinder. By establishing a static reference for the geometric impedance of the pipeline and combining real-time pulsation feature extraction and centrifugal pressure compensation, constant control of the end pressure of deep hole machining can be achieved.

[0020] As an example, the pressure and flow data sequences at the pumping station are obtained as follows: in each control cycle The system collects real-time pressure data from the pumping station. Real-time flow data of loop The data are stored in pressure data sequences and flow data sequences respectively, and the oldest data in each sequence is removed to maintain a constant sequence length. In this embodiment, a preset monitoring window length is used. Set as Control cycle ,correspond The time span.

[0021] As an example, the real-time flow rate of the hydraulic hose can be obtained through a flow sensor, and the real-time rotational speed of the polishing head can be obtained by collecting the rotational speed data of the polishing head spindle motor.

[0022] Step S20: Calculate the current instantaneous flow resistance characteristic value based on the pressure data sequence and the flow data sequence.

[0023] As an example, during the actual processing, it is necessary to sense changes in pipeline impedance in real time in order to separate the influence of oil viscosity drift. Since it is impossible to install sensors at the bottom of the hole, this stage uses the inherent flow pulse of the hydraulic pump as the excitation signal. By analyzing the pressure and flow data at the pump station end, the real-time flow resistance characteristics of the pipeline are extracted online, and then the current instantaneous flow resistance characteristic value is obtained.

[0024] The step S20, which involves maintaining a constant force for polishing the inner wall of the hydraulic cylinder, further includes steps S21 to S22, including: Step S21: Based on the similarity between the pressure data sequence and the flow data sequence, perform time-series alignment processing on the pressure data sequence and the flow data sequence.

[0025] As an example, due to the long-distance transmission characteristics and elastic volume effect of hydraulic hoses, the propagation speed of pressure waves in the pipeline is limited, resulting in a time lag (phase difference) when the flow pulsation at the pump station outlet is transmitted to the pressure sensor. If regression analysis is directly performed on the pressure and flow data at the same moment, the data points will exhibit a hysteretic circular distribution rather than a nonlinear distribution on the plane, leading to a severely distorted calculated slope. Therefore, this step performs time-series alignment processing on the pressure data sequence and the flow data sequence.

[0026] Step S21 includes: The transmission lag time is determined by the maximum value of the cross-correlation function between the pressure data sequence and the flow data sequence. The calculation result of the cross-correlation function is used to characterize the similarity between the pressure data sequence and the flow data sequence at different time displacements.

[0027] As an example, calculate the cross-correlation function between pressure data series and flow data series. The cross-correlation function measures the similarity between two sequences at different time shifts, and the calculation formula is as follows: in, Indicates at time The collected pressure signal value of the pump station. Indicates at time The acquired flow signal value (i.e., the flow signal shifted forward relative to the pressure signal) (Time units). Searching within the preset lag range makes... The displacement that reaches the maximum value is denoted as the optimal time lag frame number. .Should The value represents the time delay required for traffic fluctuations to cause pressure fluctuations, which is the transmission lag time, and limits the search range of the number of time lag frames to within the preset maximum lag window.

[0028] Based on the transmission lag time, time-series compensation is performed on the traffic data sequence to obtain the time-compensated first data sequence.

[0029] As an example, time-shift compensation is applied to the traffic data sequence based on the transmission lag time, resulting in the first data sequence after time-shift compensation.

[0030] The first data sequence is paired with the pressure data sequence to align the timing of the pressure data sequence with that of the flow data sequence.

[0031] As an example, constructing aligned data pairs: taking time... Real-time pressure data With time Real-time traffic data Pairing is performed, and multiple time points are traversed to align the time sequence of the pressure data sequence with that of the flow data sequence.

[0032] Step S22: Based on the aligned pressure data sequence and flow data sequence, calculate the current instantaneous flow resistance characteristic value.

[0033] Step S22 includes: Determine the first data pair consisting of the aligned pressure data sequence and the flow data sequence.

[0034] As an example, the real-time pressure data and real-time flow data at each moment in the pressure data sequence and flow data sequence can each form a first data pair, and thus, multiple first data pairs can be obtained.

[0035] Linear regression calculations are performed on each first data pair to obtain instantaneous flow resistance characteristic values, which are used to characterize the pressure change caused by a unit flow rate change.

[0036] As an example, after phase alignment, the system uses the least squares method to perform linear regression on the data within a preset monitoring window to extract the current impedance characteristics. Before calculation, the variance of the flow sequence is compared with a preset minimum threshold. If the variance is less than the preset minimum threshold (which can be a minimum constant greater than zero), the system is determined to be in a state of extreme steady state, and the flow resistance slope of the previous cycle is directly used. The system... Grouped data Perform univariate linear regression calculations to solve for the instantaneous flow resistance characteristic values. The calculation formula is as follows: in, and These are the arithmetic mean of real-time flow data and real-time pressure data within the preset monitoring window, respectively. The physical meaning of is: the pressure change caused by a unit change in flow rate at the current moment. The larger the value, the greater the actual flow resistance of the pipeline at present. When the system startup time is less than the preset monitoring window length, or the flow variance is less than the minimum threshold, the instantaneous flow resistance characteristic value directly calls the preset pipeline impedance reference at the current depth.

[0037] Step S30: Determine the viscosity correction coefficient based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance reference.

[0038] As an example, this step compares the measured dynamic characteristics (instantaneous flow resistance characteristic value) with the static reference (preset pipeline impedance reference) to separate the environmental influence factors, and then obtain the viscosity correction coefficient.

[0039] As an example, read the current pipe extension depth. And obtain the preset pipeline impedance reference at that location under calibrated conditions. Then, the current viscosity correction factor is calculated. : This ratio reflects the degree of deviation of the current actual impedance from the reference impedance. For example, when the oil temperature increases and causes the viscosity to decrease, the actual instantaneous flow resistance characteristic value... It will be less than the preset pipeline impedance reference, resulting in When the system is initially started, the initial value of the viscosity correction factor is set to 1.0.

[0040] Before step S30, the following are included: The pipeline extension depth and real-time pressure value at the pump station outlet are obtained during the process of the polishing head moving from the starting point to the bottom of the cylinder bore.

[0041] Based on the ratio between the real-time pressure value and the preset calibrated flow rate, the preset pipeline impedance reference is calculated for different pipeline extension depths.

[0042] As an example, after establishing a stable flow field, the system collects pressure data from the pipeline at all operating positions. The machine tool feed axis is controlled to drive the polishing head from the cylinder bore position (depth of...) Start at a constant speed (e.g., Move at a constant speed to the bottom of the cylinder bore (depth is...) During this movement, the controller operates at a fixed sampling period. (This embodiment is set as) The following data will be collected simultaneously: Pipeline extension depth The current position of the polishing head is fed back in real time by the machine tool's linear encoder or encoder.

[0043] Real-time pressure value of pump station : Real-time pressure value collected by a pressure sensor installed at the pump station outlet.

[0044] After data collection is complete, the system will use time as the data source. Convert the sequence data into spatial location This is a mapping table indexed by [index]. For each sampling time... The system calculates the pipeline impedance reference corresponding to this location. The calculation formula is as follows: in, , This indicates a preset calibration flow rate. Considering that subsequent actual processing conditions may be under high pressure and high flow rate, in order to ensure the applicability of the reference, The selection of the flow path should ensure that the flow pattern in the pipeline and the actual processing flow are in similar impedance characteristic regions (e.g., both laminar flow or early transition flow). For example, for a slender hose with an inner diameter of 10 mm, when using high-viscosity hydraulic oil, the flow pattern tends to remain in the quasi-linear region even at higher pressures. This embodiment sets... And adjust the back pressure valve in the circuit to ensure that the oil fills the pipeline and there is no cavitation. This formula calculates the pressure loss per unit flow rate at the current pipeline length, i.e., the flow resistance coefficient. Because It usually increases with the increase of pipeline length, therefore the calculated It also shows the effect of depth The trend of increasing.

[0045] After step S30, the following is included: Determine the degree of linear correlation between the aligned pressure data sequence and the flow data sequence.

[0046] Based on the degree of linear correlation, the viscosity correction coefficient is recursively updated.

[0047] As an example, calculate the goodness of fit (coefficient of determination) of this regression analysis. For univariate linear regression, the coefficient of determination is equal to the square of the Pearson correlation coefficient between the pressure data series and the flow data series (details omitted here), denoted as the degree of linear correlation. This coefficient reflects the degree of linear correlation between pressure and flow rate changes. When When the value is close to 1, it indicates that the current pressure fluctuation is mainly caused by flow pulsation, and the calculated instantaneous flow resistance characteristic value has high reliability; when When the value is low, it indicates the presence of other nonlinear disturbances in the system (such as directional valve operation or cavitation vibration), and the calculated instantaneous flow resistance characteristic value has low reliability.

[0048] As an example, to improve the system's anti-interference capability, the system utilizes the degree of linear correlation. As a weight, the viscosity correction coefficient Perform recursive updates: Specifically, when the flow is stable ( At high viscosity, the system primarily relies on current observations and responds quickly to changes in viscosity. When the flow regime is turbulent ( When the value is low, the system mainly maintains the value from the previous moment to achieve numerical filtering and holding, preventing error correction.

[0049] Step S40: Based on real-time flow rate, preset pipeline impedance reference and viscosity correction coefficient, calculate the pipeline friction loss value, and based on real-time rotation speed and preset structural constant, calculate the centrifugal pressure compensation value caused by rotation.

[0050] As an example, the pipeline friction loss value is used to characterize the pressure drop caused by pipeline resistance during the flow of fluid from the pump station to the end, and the centrifugal pressure compensation value is used to characterize the pressure increment caused by the centrifugal effect on the internal oil due to the rotation of the polishing head.

[0051] As an example, during the process of fluid flowing from the pump station to the end of the polishing head, it needs to overcome pipeline resistance, resulting in a pressure drop. In order to ensure that the end receives sufficient pressure, the pump station must output additional pressure to compensate for the loss. This step accurately calculates this loss by combining geometric and environmental factors to obtain the pressure loss value along the pipeline.

[0052] As an example, when the hydraulic oil inside the polishing head rotates at high speed with the spindle, it is thrown against the cylinder wall by centrifugal force, creating additional radial pressure in the contact area between the polishing head and the cylinder wall. This pressure component is independent of the pump station's oil supply pressure. If it is not deducted, the actual contact force will exceed the target value as the rotational speed increases. Based on this, the centrifugal pressure compensation value is calculated.

[0053] In step S40, the pressure loss along the pipeline is calculated based on real-time flow rate, preset pipeline impedance reference, and viscosity correction coefficient, including: The actual transmission impedance value is calculated based on the preset pipeline impedance reference and viscosity correction factor.

[0054] As an example, the actual transmission impedance value The calculation method can be: in, This represents the basic resistance caused by the length and bend of the pipe; This represents the resistance discount or gain resulting from the oil's temperature and thinness; multiplying the two yields the corrected actual flow capacity of the pipeline under the current operating conditions. For example, when the oil temperature rises ( When the actual impedance is less than the geometric reference impedance, the actual impedance will be less than the geometric reference impedance.

[0055] The pressure loss along the pipeline is calculated based on the product of the actual transmission impedance value and the real-time flow rate.

[0056] As an example, calculate the pressure loss along the pipeline based on the current flow conditions. Receives real-time flow detected by flow sensors Perform the following operations: Real-time traffic Impact: Pressure loss is directly proportional to flow rate; the greater the flow rate, the greater the pressure drop caused by friction when the fluid flows through the pipeline, and the greater the required compensation value.

[0057] Meaning of the calculation results: The pressure value that the pump station must prepay in order to deliver the oil to the end of the polishing head is quantified, and this value will be included as an additional factor in the final pressure balance calculation.

[0058] Among them, step S40, which calculates the centrifugal pressure compensation value generated by rotation based on real-time rotational speed and preset structural constants, includes: The centrifugal pressure compensation value generated by rotation is calculated based on the product of real-time rotation speed, preset structural constant, and preset hydraulic oil density.

[0059] As an example, the preset structural constant is the structural constant of the polishing head, which characterizes the sensitivity of the internal geometry of the polishing head to the centrifugal pressurization effect of the fluid. It can be obtained as follows: The estimation is based on the design dimensions of the internal oil cavity of the polishing head. It is assumed that the maximum radius of gyration of the hydraulic oil within the polishing head's internal cavity is... (Usually corresponds to the inner radius of the polishing head), the minimum gyration radius is (Usually corresponding to the oil inlet or shaft radius), then the preset structural constant is... It can be calculated using the following formula: This formula is derived based on the principle of fluid rotational dynamics, showing that the larger the radius of rotation, the more significant the centrifugal pressurization effect.

[0060] As an example, the real-time speed of the spindle motor is collected in real time. (unit: ), and call the preset structure constants. Mechanical transmission conversion coefficient (Determined by the effective working area of ​​the hydraulic cylinder inside the polishing head and the transmission efficiency of the mechanical structure) and the preset hydraulic oil density. (For example, The centrifugal pressure compensation value is calculated using the fluid rotation pressure formula. : In the formula, real-time rotational speed The effect: Centrifugal pressure is proportional to the square of the rotational speed. This means that when the polishing head speed doubles, the additional pressure generated by centrifugation will increase to four times the original. The system must accurately calculate this non-linear increment in order to perform a significant reverse subtraction in subsequent steps.

[0061] Preset structural constants The larger this constant is, the larger the inner cavity size of the polishing head, and the greater the centrifugal pressure generated at the same rotational speed. It will be included as a deduction item in the final pressure balance calculation.

[0062] Step S50: Combine the preset process target pressure value, the pipeline friction loss value, and the centrifugal pressure compensation value to generate a pump station output pressure command to drive the pump station to maintain constant force output.

[0063] As an example, the pump station output pressure command can be the command that the controller finally sends to the hydraulic pump corresponding to the pressure set value. By actively adjusting the oil supply pressure, the transmission loss of pipelines and centrifugal interference are offset, ensuring that the actual force reaching the end of the polishing head is always maintained at the target value set by the process.

[0064] Step S50 includes: The preset process target pressure value is superimposed with the pressure loss value along the pipeline to obtain the superimposed pressure value.

[0065] As an example, according to Pascal's principle and force balance, the actual contact pressure of the polishing head against the cylinder wall is determined by the pump station's oil supply pressure, pipeline friction loss, internal centrifugal pressurization of the polishing head, and the frictional resistance of the seals. To ensure that the actual contact pressure equals the target process pressure... The controller performs the reverse calculation.

[0066] The superimposed pressure value is subtracted from the centrifugal pressure compensation value to obtain the pump station output pressure value, and the corresponding pump station output pressure command is generated.

[0067] As an example, the pump station output pressure value The calculation method can be: In the formula, The preset process target pressure value can be a constant contact pressure value set by the user or specified in the process document. This represents the sealing start-up pressure constant, which can be a preset empirical constant. It characterizes the minimum pressure required to overcome the static friction of the polishing head seal ring. This value is usually provided by the equipment manufacturer, for example, set to... , This indicates the pressure loss along the pipeline. This indicates the centrifugal pressure compensation value.

[0068] and As a basic pressure requirement, the two are directly added together. The pumping station must provide this pressure to establish contact and overcome friction.

[0069] (Positive compensation term): Due to pipeline resistance, this portion of pressure is lost during transmission. Therefore, the system adds this to the command, causing the pump station to output more pressure to compensate for the loss.

[0070] (Negative compensation term): Due to the additional centrifugal pressure generated by high-speed rotation, this pressure will be superimposed on the contact surface. In order to prevent the total pressure from exceeding the limit, the system subtracts it from the command, allowing the pump station to output less and give up the share contributed by centrifugal force.

[0071] Through this combination of addition and subtraction, regardless of how long the pipeline extends (affecting...), How the rotational speed changes (affects) Ultimately, the pressure acting on the cylinder wall remains constant.

[0072] Before sending the calculated command to the actuator, a safety limit check must be performed to prevent damage to the hydraulic lines due to excessive command pressure caused by sensor failure, calculation abnormalities, or extreme operating conditions.

[0073] Specifically, a maximum permissible safety pressure is preset. (For example, set to 80% of the rated pressure resistance of the hydraulic hose, such as...) Furthermore, the controller... Make a judgment: like If the calculated value is less than zero, the calculated value will be output directly. When the value is less than zero, the electrical signal will be output as the preset reference back voltage value (e.g., 0V or 1V).

[0074] like This forces the output value to be clamped to... It also sends an overpressure alarm signal to the operating interface.

[0075] Ultimately, after being limited It is converted into the corresponding electrical signal (e.g.) voltage or The current drives the electro-proportional pressure reducing valve or servo motor of the hydraulic pump station to adjust the actual outlet pressure of the pump station. This control process occurs in each control cycle ( The internal loop execution achieves high-frequency response pressure closed-loop control.

[0076] This application provides a constant force maintenance method for polishing the inner wall of a hydraulic cylinder. In this application, by acquiring the pressure data sequence and flow data sequence of the pump station, the real-time flow rate of the hydraulic hose, and the real-time rotation speed of the polishing head during the polishing operation, and then calculating the current instantaneous flow resistance characteristic value based on the pressure data sequence and flow data sequence, the viscosity correction coefficient is determined based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance benchmark. By establishing a spatial static benchmark and combining it with online viscosity correction, the system can not only compensate for the pressure drop caused by the change in pipe length, but also correct the viscosity drift caused by the increase in oil temperature in real time, ensuring the consistency of the processing pressure throughout the entire stroke. Based on real-time flow rate, preset pipeline impedance reference, and viscosity correction coefficient, the pipeline friction loss value is calculated. Based on real-time rotation speed and preset structural constant, the centrifugal pressure compensation value generated by rotation is calculated. The preset process target pressure value, pipeline friction loss value, and centrifugal pressure compensation value are combined to generate the pump station output pressure command. Through an independent centrifugal pressure compensation mechanism, the centrifugal pressure component caused by rotation speed is actively deducted when generating the oil supply command, which effectively prevents over-cutting of the workpiece inner wall caused by the surge of end contact force during high-speed operation. Thus, the contact pressure of the polishing head is stably maintained without installing sensors to directly measure the end pressure.

[0077] This application embodiment also provides a constant force maintaining device for polishing the inner wall of a hydraulic cylinder barrel. The device includes: a memory, a processor, and a constant force maintaining program for polishing the inner wall of a hydraulic cylinder barrel stored in the memory and executable on the processor. The constant force maintaining program for polishing the inner wall of a hydraulic cylinder barrel is configured to implement the steps of the constant force maintaining method for polishing the inner wall of a hydraulic cylinder barrel as described above.

[0078] Reference Figure 2 , Figure 2 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application.

[0079] like Figure 2 As shown, the constant force maintaining device for polishing the inner wall of a hydraulic cylinder may include: a processor 1001, a memory 1003, and a communication bus 1002. The communication bus 1002 is used to realize the connection and communication between the processor 1001 and the memory 1003.

[0080] Optionally, the constant force maintaining device for polishing the inner wall of the hydraulic cylinder may also include a user interface, a network interface, a camera, RF (Radio Frequency) circuitry, sensors, a WiFi module, etc. The user interface may include a display screen and an input submodule such as a keyboard; optional user interfaces may also include standard wired or wireless interfaces. The network interface may include standard wired or wireless interfaces (such as a Wi-Fi interface).

[0081] Those skilled in the art will understand that Figure 2 The constant force maintaining device structure shown in the figure for polishing the inner wall of a hydraulic cylinder barrel does not constitute a limitation on the constant force maintaining device for polishing the inner wall of a hydraulic cylinder barrel. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0082] like Figure 2 As shown, the memory 1003, serving as a storage medium, may include an operating system, a network communication module, and a constant force maintenance program for polishing the inner wall of the hydraulic cylinder barrel. The operating system is a program that manages and controls the hardware and software resources of the constant force maintenance device for polishing the inner wall of the hydraulic cylinder barrel, supporting the operation of the constant force maintenance program and other software and / or programs. The network communication module is used to enable communication between the various components within the memory 1003, as well as communication with other hardware and software in the constant force maintenance system for polishing the inner wall of the hydraulic cylinder barrel.

[0083] exist Figure 2 In the constant force maintaining device for polishing the inner wall of a hydraulic cylinder shown, the processor 1001 is used to execute the constant force maintaining program for polishing the inner wall of a hydraulic cylinder stored in the memory 1003, and implement the steps of the constant force maintaining method for polishing the inner wall of a hydraulic cylinder as described above.

[0084] The specific implementation method of the constant force maintaining device for polishing the inner wall of hydraulic cylinder barrel in this application is basically the same as the embodiments of the constant force maintaining method for polishing the inner wall of hydraulic cylinder barrel described above, and will not be repeated here.

[0085] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system 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 system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0086] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0087] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0088] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

[0089] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0090] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A constant force maintaining method for polishing an inner wall of a cylinder of a hydraulic cylinder, characterized by, The method includes: Acquire pressure and flow data sequences at the pump station end, real-time flow of hydraulic hoses, and real-time rotational speed of the polishing head during the polishing operation; Based on the pressure data sequence and flow data sequence, calculate the current instantaneous flow resistance characteristic value; The pipeline extension depth and the real-time pressure value at the pump station outlet are obtained during the process of the polishing head moving from the starting point to the bottom of the cylinder bore. Based on the ratio between the real-time pressure value and the preset calibrated flow rate, the preset pipeline impedance reference for different pipeline extension depths is calculated. The viscosity correction coefficient is determined based on the ratio between the instantaneous flow resistance characteristic value and the preset pipeline impedance benchmark. Determine the degree of linear correlation between the aligned pressure data sequence and the flow data sequence; Based on the degree of linear correlation, the viscosity correction coefficient is recursively updated; Based on the real-time flow rate, the preset pipeline impedance reference, and the viscosity correction coefficient, the pipeline friction loss value is calculated, and based on the real-time rotational speed and the preset structural constant, the centrifugal pressure compensation value caused by rotation is calculated. The calculation of the centrifugal pressure compensation value generated by rotation based on the real-time rotational speed and the preset structural constant specifically includes: The centrifugal pressure compensation value generated by rotation is calculated based on the product of the real-time rotation speed, the preset structural constant, and the preset hydraulic oil density. The preset process target pressure value, the pipeline friction loss value, and the centrifugal pressure compensation value are combined to generate the pump station output pressure command, specifically including: The preset process target pressure value is superimposed with the pipeline friction loss value to obtain the superimposed pressure value; The superimposed pressure value is subtracted from the centrifugal pressure compensation value to obtain the pump station output pressure value, and a pump station output pressure command corresponding to the pump station output pressure value is generated to drive the pump station to maintain constant force output.

2. The constant force maintaining method for polishing the inner wall of a hydraulic cylinder barrel according to claim 1, characterized by, The calculation of the current instantaneous flow resistance characteristic value based on the pressure data sequence and flow rate data sequence includes: Based on the similarity between the pressure data sequence and the flow data sequence, time-series alignment processing is performed on the pressure data sequence and the flow data sequence; Based on the aligned pressure and flow data sequences, the current instantaneous flow resistance characteristic value is calculated.

3. The constant force maintenance method for polishing the inner wall of a hydraulic cylinder as described in claim 2, characterized in that, The step of performing time-series alignment processing on the pressure data sequence and the flow data sequence based on the similarity between them includes: Based on the maximum value of the cross-correlation function between the pressure data sequence and the flow data sequence, the transmission lag time is determined. The calculation result of the cross-correlation function is used to characterize the similarity between the pressure data sequence and the flow data sequence at different time shifts. Based on the transmission lag time, the traffic data sequence is time-compensated to obtain the time-compensated first data sequence; The first data sequence is paired with the pressure data sequence to align the timing of the pressure data sequence with that of the flow data sequence.

4. The constant force maintenance method for polishing the inner wall of a hydraulic cylinder as described in claim 2, characterized in that, The calculation of the current instantaneous flow resistance characteristic value based on the aligned pressure data sequence and flow data sequence includes: Determine the first data pair consisting of the aligned pressure data sequence and the flow data sequence; Linear regression calculation is performed on each of the first data pairs to obtain instantaneous flow resistance characteristic values, wherein the instantaneous flow resistance characteristic values ​​are used to characterize the pressure change caused by a unit flow rate change.

5. The constant force maintenance method for polishing the inner wall of a hydraulic cylinder as described in claim 1, characterized in that, The calculation of the pipeline friction loss value based on the real-time flow rate, the preset pipeline impedance reference, and the viscosity correction coefficient includes: The actual transmission impedance value is calculated based on the preset pipeline impedance reference and the viscosity correction coefficient. The pressure loss along the pipeline is calculated based on the product of the actual transmission impedance value and the real-time flow rate.

6. A constant force maintaining device for polishing the inner wall of a hydraulic cylinder barrel, characterized in that, The apparatus includes: a memory, a processor, and a constant force maintenance program for polishing the inner wall of a hydraulic cylinder barrel, stored in the memory and executable on the processor, the constant force maintenance program for polishing the inner wall of a hydraulic cylinder barrel being configured to implement the steps of the constant force maintenance method for polishing the inner wall of a hydraulic cylinder barrel as described in any one of claims 1 to 5.

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