Rapid and accurate prediction method for duty ratio-equivalent output flow characteristics of high-speed switch valve

Abstract

The invention discloses a rapid and accurate prediction method for duty ratio-equivalent output flow characteristics of a high-speed switch valve, and belongs to the field of high-speed switch valves. The method comprises the following steps: firstly, acquiring dynamic characteristic parameters of a high-speed switch valve to be tested, wherein the dynamic characteristic parameters comprise opening lag time, opening motion time, closing lag time, closing motion time and current adjusting time; then, based on the dynamic characteristic parameters, a mathematical model of the equivalent output flow and the switch duty ratio of the high-speed switch valve is established, and duty ratio boundaries of a dead zone, a linear zone and a saturation zone in the duty ratio-equivalent output flow characteristic are obtained through derivation; actual measurement equivalent output flow data of the upper limit and the lower limit of a linear area are obtained through a small number of experiments and substituted into the mathematical model, and a duty ratio-equivalent output flow characteristic curve is generated by combining the duty ratio boundary. According to the method, rapid and accurate prediction of the duty ratio-equivalent output flow characteristic of the high-speed switch valve can be realized only through one-time dynamic behavior and current characteristic measurement and a small number of experiments.

Description

Technical Field

[0001] This invention belongs to the field of high-speed switching valves, and more specifically, relates to a rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of high-speed switching valves. Background Technology

[0002] High-speed switching valves (HSVs), as the core control element of digital hydraulic systems (DHS), have significant advantages such as compact structure, fast response, low cost and strong anti-contamination capability. By adjusting the switching duty cycle (SDR) to regulate the equivalent output flow (EOF) through two discrete working states of "fully open" and "fully closed", they can achieve flow and pressure control of DHS. They have been widely used in various industrial hydraulic control scenarios and are key basic components to ensure the accurate operation of DHS.

[0003] During DHS operation, the duty cycle-equivalent output flow (SDR-EOF) characteristic curve of the HSV is the core indicator for measuring its control performance. Due to the inherent switching hysteresis of the HSV, this curve naturally has dead zone, linear zone, and saturation zone: the dead zone corresponds to the region where the valve core is not open when the duty cycle is too small and EOF is always 0; the saturation zone corresponds to the region where the valve core is fully open when the duty cycle is too large and EOF reaches its maximum value and remains stable; the linear zone is the core region where the equivalent output flow changes uniformly with the duty cycle and is most suitable for stable DHS control. Accurately obtaining the SDR-EOF characteristic curve not only provides a basis for selecting the linear operating range of the HSV for DHS, but also effectively avoids problems such as system unresponsiveness caused by the dead zone and excessive flow caused by the saturation zone, which is crucial for improving the overall control accuracy and stability of the DHS.

[0004] In existing technologies, the SDR-EOF characteristic detection of HSVs mainly relies on two types of methods: direct testing and indirect testing. Direct testing methods use flow meters, measuring cups, and weighing tanks as core tools. The principle is to experimentally measure the EOF at a specific duty cycle: for example, using a flow meter to test the equivalent output flow rate in the saturation zone of the HSV under different pressures, or using a measuring cup to collect the output oil volume over a fixed time period and a weighing tank to monitor the change in oil mass, and indirectly converting it to obtain the equivalent output flow rate, thereby gradually obtaining the flow rate data corresponding to different duty cycles. Indirect testing methods monitor the motion state (displacement, velocity) of the controlled object of the HSV (such as a proportional valve core or hydraulic cylinder), and combine the correlation between the performance of the controlled object and the equivalent output flow rate to deduce the EOF of the HSV in reverse. For example, by detecting the change in valve core motion after being affected by liquid damping, or analyzing the resistance and pressure difference during cylinder motion, the flow characteristics can be indirectly estimated.

[0005] However, existing detection methods have significant limitations and are difficult to meet practical application needs: First, the testing efficiency is extremely low. Whether through direct testing, which requires traversing the full range of duty cycle points from 0 to 100% (usually requiring 30-50 experimental points) and repeating the experiment at each point to ensure data stability, or through indirect testing, which requires adjusting the duty cycle multiple times to construct a complete curve, both methods consume a lot of time. Traditional methods can take up to 40 minutes for a single test, making it difficult to adapt to efficient R&D and on-site debugging scenarios. Second, the testing accuracy is affected by multiple factors. In direct testing, the flow dispersion caused by the high-frequency switching of the HSV will cause errors in the flowmeter measurement, and the residual pressure inside the HSV will further affect the accuracy of the results. Indirect testing, because the resistance and pressure difference of the controlled object change when it is monitored, the original equivalent output flow rate will shift, making it difficult to guarantee accuracy. Third, long-term testing is prone to additional errors. Continuous experiments will cause the temperature of the HSV coil to rise, thereby changing its dynamic performance and causing the duty cycle-equivalent output flow rate curve to shift, further reducing the reliability and consistency of the test results.

[0006] Therefore, existing methods for detecting duty cycle-equivalent output flow characteristics are insufficient in terms of efficiency, accuracy, and stability, making it difficult to meet the actual needs of DHS design optimization, production debugging, and field applications. There is an urgent need for a predictive method based on the dynamic behavior of the HSV itself, which does not require extensive experimental traversal. This method should be able to quickly and quantitatively obtain complete duty cycle-equivalent output flow characteristic curves under limited experimental conditions, significantly improving testing efficiency, reducing experimental costs, and enhancing the reliability and versatility of the results. This would provide technical support for the efficient development and precise control of DHS. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a rapid and accurate prediction method for the duty cycle-equivalent output flow (SDR-EOF) characteristics of high-speed switching valves. This method theoretically analyzes the correlation between the duty cycle-EOF characteristics of high-speed switching valves and their dynamic time parameters (including opening / closing lag time, opening / closing motion time, current adjustment time, and current holding time). Then, through experiments, the dynamic time parameters are directly detected using a laser displacement sensor or indirectly obtained through coil current characteristics. Based on these key parameters, the duty cycle boundary of the characteristic region is calculated. Combined with measured equivalent output flow values ​​at a few key points, a complete duty cycle-EOF characteristic curve can be quickly constructed.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A rapid and accurate method for predicting the duty cycle-equivalent output flow characteristics of a high-speed switching valve includes the following steps: 1) Under the selected drive mode, perform periodic opening and closing tests on the high-speed switching valve under test, record the start and end times of each movement state of the valve core and the time of coil current change, and obtain the dynamic time parameters of the high-speed switching valve; the dynamic time parameters include opening lag time, opening movement time, opening current adjustment time, closing lag time, closing movement time, and closing current adjustment time. 2) Based on the obtained dynamic time parameters and opening / closing cycle, calculate the duty cycle boundaries of different intervals in the duty cycle-equivalent output flow characteristic of the high-speed switching valve under test. The duty cycle boundaries include the upper limit of the dead zone. α 1 lower limit of the linear region α 1 + α 2 Upper limit of linear region 1- α 3 - α 4 and the lower limit of the saturation region 1- α 4 The areas between the upper limit of the dead zone and the lower limit of the linear zone, and between the upper limit of the linear zone and the lower limit of the saturation zone, are all nonlinear regions. 3) Establish the duty cycle-flow characteristic relationship based on the measured equivalent output flow rate: when the duty cycle is in the dead zone, determine the relationship that the equivalent output flow rate is always 0; when the duty cycle is in the linear zone, establish the linear fitting relationship based on the measured equivalent output flow rate values ​​of the upper and lower limits of the linear zone; when the duty cycle is in the saturation zone, determine the relationship that the equivalent output flow rate is always 100%. 4) Combine the equivalent output flow rate and duty cycle relationship for different duty cycle intervals, and establish a coordinate system with duty cycle as the horizontal axis and equivalent output flow rate as the vertical axis. The dead zone is represented by a horizontal line where the equivalent output flow rate is always 0, the linear zone is represented by a linear fitting line, and the saturation zone is represented by a horizontal line where the equivalent output flow rate is always 100%. This yields the duty cycle-equivalent output flow rate characteristic curve of the high-speed switching valve that does not include the nonlinear zone. The duty cycle-equivalent output flow rate characteristic curve is the relationship curve between the duty cycle and the equivalent output flow rate at that duty cycle.

[0009] Preferably, the dynamic time parameter in step 1) is calculated as follows: Enable lag time t don The difference between the moment the valve core begins to open and the initial moment of the opening phase; Start your workout time t mon The difference between the moment the valve core is fully open and the moment it begins to open; Turn-on current adjustment time t aonThe difference between the moment when the coil current reaches a stable and constant value during the opening phase of a high-speed switching valve and the moment when the valve core is fully open. Closure time t doff The difference between the moment the valve core begins to close and the initial moment of the closing phase; Turn off exercise time t moff The difference between the moment the valve core is fully closed and the moment it begins to close; Current adjustment time off t aoff The difference between the moment when the coil current decays to zero during the closing phase of a high-speed switching valve and the moment when the valve core is completely closed.

[0010] Preferably, the measured equivalent output flow rate values ​​of the upper and lower limits of the linear region in step 3) are obtained by controlling the high-speed switching valve to operate stably under the condition that the duty cycle is equal to the lower limit α1+α2 of the linear region and the upper limit α1-α3-α4 of the linear region, respectively, and collecting data at fixed intervals using a measuring cup. t Internal output oil volume v Based on the actual measured equivalent output flow rate Calculated.

[0011] Preferably, the linear fitting relationship of the linear region in step 3) is specifically as follows: ,in q For any duty cycle within the linear region, the predicted equivalent output flow rate is... q low This represents the measured equivalent output flow rate corresponding to the lower limit of the linear region. q high This represents the measured equivalent output flow rate corresponding to the upper limit of the linear region. α This represents any duty cycle value within the linear region.

[0012] A rapid and accurate prediction system for the duty cycle-equivalent output flow characteristics of a high-speed switching valve, applicable to the aforementioned rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of a high-speed switching valve, comprising: Opening and closing test system: used to perform periodic opening and closing tests on the high-speed switching valve under test in single-voltage drive mode, including a data acquisition device and a measuring cup; the data acquisition device is used to acquire valve core displacement data and output dynamic time parameters. t don , t mon , t aon , t doff , t moff , t aoffThe measuring cup is used to calculate the measured equivalent output flow rate; Duty cycle boundary calculation unit: used to calculate the duty cycle boundary based on the dynamic time parameters output by the start-up / shutdown test system and the set switching frequency. f Calculate the duty cycle boundary of the duty cycle-equivalent output flow characteristic region. α 1 , α 1 + α 2 1- α 3 - α 4 and 1- α 4 ; Duty cycle-equivalent output flow curve generation module: Based on the duty cycle boundary and the measured equivalent output flow value obtained from the measuring cup, it establishes the relationship between duty cycle and equivalent output flow, including dead zone, linear zone and saturation zone, and generates a duty cycle-equivalent output flow characteristic curve including dead zone, linear zone and saturation zone.

[0013] Compared with the prior art, the present invention has the following effects and advantages: (1) This invention deeply binds the dynamic time parameters such as the opening and closing lag time, opening and closing motion time, and current adjustment time of the high-speed switching valve with the duty cycle-equivalent output flow characteristics. The dynamic time parameters can be obtained directly by collecting the valve core displacement, or indirectly derived from the coil current characteristics when the displacement sensor cannot be installed. There is no need to traverse the full range of duty cycle points from 0 to 100%. The characteristic curve can be quickly generated by only one dynamic characteristic measurement and a small number of key point flow tests, which greatly shortens the test time and solves the problem of low efficiency of traditional methods. (2) The present invention distinguishes the characteristic constraint mechanism of different duty cycle intervals, and accurately defines the boundaries of dead zone, nonlinear zone, linear zone and saturation zone through dynamic parameters. The dead zone is determined by the start-up lag time. t don The dominant and linear regions need to cover the complete dynamic time; the saturation region is determined by the shutdown lag time. t doff This approach, which prioritizes the identification of characteristic regions, avoids the problem of ambiguity in traditional testing and significantly improves prediction accuracy. (3) This invention establishes a mathematical relationship between dynamic time parameters and duty cycle boundaries of characteristic areas. By calculating the duty cycle value of key points through a clear formula, a curve can be constructed by combining a small amount of measured flow data. It does not rely on complex experimental equipment and a large amount of discrete data fitting, which not only reduces experimental costs but also enhances the repeatability and universality of the results, effectively avoiding the fluctuations in results caused by factors such as oil temperature and installation errors in traditional testing. Attached Figure Description

[0014] Figure 1 The dynamic characteristic curve of the high-speed switching valve is shown. Figure 2 This is a schematic diagram of a system for indirectly detecting valve core displacement using current characteristics. Figure 3 The switching duty cycle-equivalent output flow characteristic curve of a high-speed switching valve; Figure 4 This is a graph showing the prediction effect under single-voltage drive mode; Figure 5 This is a graph showing the prediction effect under the three-voltage drive mode.

[0015] Figure 2 In the middle, 1-voltage source, 2-computer, 3-current acquisition card, 4-high-speed switching valve driver, 5-high-speed switching valve. Detailed Implementation

[0016] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0017] The duty cycle-equivalent output flow (SDR-EOF) characteristic of a high-speed switching valve is closely related to its dynamic characteristics. In this field, the duty cycle-equivalent output flow characteristic curve is usually plotted using the valve core movement state (starting to open, fully open, starting to close, fully closed) as the criterion. This curve characterizes the variation of the equivalent output flow of the high-speed switching valve under different fixed duty cycles. When a high-speed switching valve operates at a certain fixed duty cycle, its equivalent output flow is affected by the coupling influence of the valve core opening and closing lag time, opening and closing motion time, and current stability characteristics, forming four characteristic regions on its SDR-EOF characteristic curve: dead zone, linear region, nonlinear region, and saturation region. The ability to accurately determine the boundary positions of these four characteristic regions directly determines the control accuracy and stability of the digital hydraulic system. Among them, the dead zone corresponds to the region where the valve core is not open when the duty cycle is too small and the EOF is always 0. The nonlinear zone is divided into the opening nonlinear zone and the closing nonlinear zone. The opening nonlinear zone corresponds to the region where the valve core fails to stably reach the fully open state and the output flow is lower than the expected flow value of the linear zone. The closing nonlinear zone corresponds to the region where the valve core fails to stably reach the fully closed state and the output flow is higher than the expected flow value of the linear zone. The saturation zone corresponds to the region where the valve core is continuously fully open when the duty cycle is too large and the EOF reaches the maximum value and is stable. The linear zone is the core region where the equivalent output flow changes uniformly with the duty cycle and is most suitable for stable DHS control.

[0018] This invention provides a rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of a high-speed switching valve. Due to the complex physical mechanisms of the nonlinear region, it is difficult to establish an accurate and generalizable prediction model; therefore, this invention does not predict the duty cycle-equivalent output flow characteristics within this region. The prediction method of this invention includes the following steps: Step 1) Under the selected drive mode, perform periodic opening and closing tests on the high-speed switching valve under test, record the start and end times of each movement state of the valve core and the time of coil current change, and obtain the dynamic time parameters of the high-speed switching valve; the start and end times of each movement state of the valve core include the start opening time, the full opening time, the start closing time, and the full closing time; the dynamic time parameters include the opening lag time. t don Start your exercise time t mon Turn-on current adjustment time t aon Closure time t doff Turn off exercise time t moff , current adjustment time t aoff .

[0019] The selected driving mode can be a single-voltage driving mode, a three-voltage driving mode, or a pre-loaded voltage driving mode. Under different driving modes, only the corresponding dynamic time parameters need to be obtained according to step 1), and the duty cycle boundary can be calculated and characteristic curves generated using the same mathematical model, without adjusting the modeling logic. The single-voltage driving mode divides one opening and closing cycle of the high-speed switching valve into an opening phase and a closing phase: a fixed high voltage (e.g., 24V) is applied during the opening phase to provide sufficient electromagnetic force for the valve core to open; zero voltage is applied during the closing phase, and the valve core is reset by spring force. This invention adopts a single-voltage driving mode, such as... Figure 1 As shown, the opening phase refers to the entire process from the triggering of the "open signal" to the full opening of the valve core, and the closing phase refers to the entire process from the triggering of the "close signal" to the full closing of the valve core; the opening and closing cycle time of a high-speed switching valve. ,in t on , t off These are the total opening time and total closing time of the high-speed switching valve, and the opening / closing cycle frequency. Duty cycle of one start-stop cycle The three-voltage drive mode divides a high-speed switching valve's opening and closing cycle into a high-voltage opening phase, a low-voltage sustaining phase, and a reverse high-voltage closing phase, representing an optimization and upgrade of the single-voltage drive. During the high-voltage opening phase, a fixed high voltage (e.g., 24V) is applied to rapidly increase the coil current and shorten the opening hysteresis time. During the low-voltage sustaining phase, a low voltage (e.g., equivalent to 5-8V) is applied to maintain the coil current at a stable value 5%-10% above the critical closing current. During the reverse high-voltage closing phase, a reverse high voltage (e.g., -24V) is applied to accelerate the decay of the coil current and shorten the closing hysteresis time.

[0020] The preloaded multi-voltage drive mode is an optimized drive mode that adds a preload phase to the three-voltage drive mode. This means that one turn-on / off cycle is divided into a preload phase, a high-voltage turn-on phase, a low-voltage sustaining phase, and a reverse high-voltage turn-off phase. During the preload phase, a preload voltage (equivalent to 7-8V) is applied, causing the coil current to rise to the critical turn-on current in the single-voltage drive mode ahead of time. The following 5%-10% stable value shortens the start-up lag time; the voltage control logic for the remaining stages is consistent with the three-voltage drive mode.

[0021] The total startup time varies depending on the driving method. t on All of these can be further divided into start-up lag time. t don Start your exercise time t mon Turn-on current adjustment time t aon and turn-on current sustaining time t hon Among them, the start-up lag time t don This is the time from the initial moment of the opening phase to the moment the valve core begins to open; at the moment the valve core begins to open, the electromagnetic force just overcomes the resistance such as spring compression force and friction, and at this time the corresponding coil current rises to the critical opening current. I on Start your workout time t mon The time from the start of valve core opening to full opening; opening current adjustment time. t aon This refers to the period from when the valve core is fully open to when the high-speed switching valve HSV opens, during which the coil current reaches a stable and constant value. I son Time; On-current sustaining time t hon This refers to the HSV turn-on phase where the coil current reaches a stable and constant value. I sonThe time during which this stable value is maintained until the "off signal" is triggered; Correspondingly, total shutdown time t off It can also be further divided into closing lag time t doff Turn off exercise time t moff , current adjustment time t aoff and the duration of the off current t hoff Among them, the closing lag time t doff This is the time from the initial moment of the closing phase to the moment the valve core begins to close; at the moment the valve core begins to close, the spring return force exactly counteracts the resistance of electromagnetic force and friction, and the corresponding coil current drops to the critical closing current. I off Turn off exercise time t moff The time from when the valve core begins to close to when it is fully closed; the closing current adjustment time. t aoff The time from when the valve core is fully closed to when the HSV closing phase coil current drops to a stable constant value of 0; closing current sustaining time. t hoff This refers to the time from when the coil current reaches a stable and constant value of 0 during the HSV off-phase until the "on signal" is triggered, during which the stable value is maintained.

[0022] Among them, the valve core begins to open when it is in a critical opening state; the valve core is fully open when it is fully open; the valve core begins to close when it is in a critical closing state; and the valve core is fully closed when it is fully closed.

[0023] It should be noted that in the three-voltage drive mode or the preloaded voltage drive mode, the preset voltage applied during the start-up phase is a segmented voltage.

[0024] Therefore, by simply performing an opening and closing test on the high-speed switching valve under the selected drive mode, recording the movement state of the valve core and the start and end times of each movement state, the opening time, full opening time, closing time, and full closing time of the valve core can be obtained. The opening lag time of the high-speed switching valve can then be calculated. t don Start your exercise time t mon Closure time t doff and the time to turn off exercise t moff .

[0025] It should be noted that the periodic opening and closing test should last for at least 5 consecutive opening and closing cycles. When obtaining the dynamic time parameters of the high-speed switching valve, the average value of the parameter values ​​for the 5 consecutive opening and closing cycles should be taken to offset the impact of oil pressure fluctuations on the dynamic performance of the high-speed switching valve.

[0026] The valve core's motion state and its corresponding timing can be obtained through either direct or indirect detection, as detailed below: Direct detection: For high-speed switching valves equipped with valve core displacement sensors or capable of being fitted with displacement sensors, the valve core displacement curve is acquired in real time using a laser displacement sensor. Key moments are determined based on abrupt changes in the slope of the displacement curve. When the slope of the displacement curve changes from 0 to a significantly positive value at a certain point, that point corresponds to the moment the valve core begins to open; when the slope of the displacement curve changes from a significantly positive value to 0 at a certain point, that point corresponds to the moment the valve core is fully open; when the slope of the displacement curve changes from 0 to a significantly negative value at a certain point, that point corresponds to the moment the valve core begins to close; and when the slope of the displacement curve changes from a significantly negative value to 0 at a certain point, that point corresponds to the moment the valve core is fully closed.

[0027] Indirect detection: For high-speed switching valves that lack a valve core displacement sensor or cannot be equipped with one, the valve core motion state is indirectly deduced through the characteristics of its coil current. When the coil current increases and its second derivative shows a sudden change point (convex point), the valve core begins to open; when the first derivative of the coil current curve shows an upward sudden change point (concave point), the corresponding valve core is fully open; when the coil current curve decreases and its second derivative shows a sudden change point (convex point), the valve core begins to close; when the first derivative of the coil current curve shows an upward sudden change point (concave point), the valve core is fully closed.

[0028] Step 2) Based on the obtained dynamic time parameters and opening / closing cycle, calculate the duty cycle boundaries of different intervals in the duty cycle-equivalent output flow characteristic of the high-speed switching valve under test. The duty cycle boundaries include the upper limit of the dead zone. α 1 lower limit of the linear region α 1 + α 2 Upper limit of linear region 1- α 3 - α 4 and the lower limit of the saturation region 1- α 4 The areas between the upper limit of the dead zone and the lower limit of the linear zone, as well as between the upper limit of the linear zone and the lower limit of the saturation zone, are all nonlinear regions.

[0029] Step 3) Within different duty cycle ranges, establish the duty cycle-flow characteristic relationship based on the measured equivalent output flow rate: when the duty cycle is in the dead zone, determine the relationship that the equivalent output flow rate is always 0; when the duty cycle is in the linear zone, establish the linear fitting relationship based on the measured equivalent output flow rate values ​​of the upper and lower limits of the linear zone; when the duty cycle is in the saturation zone, determine the relationship that the equivalent output flow rate is always 100%.

[0030] In the duty cycle-equivalent output flow characteristic curve of a high-speed switching valve (HSV), there are four characteristic regions: dead zone, nonlinear zone, linear zone, and saturation zone. Figure 3 As shown, the duty cycle length corresponding to the dead zone is The duty cycle length corresponding to opening the nonlinear region is The duty cycle length corresponding to closing the nonlinear region is The duty cycle length corresponding to the saturation region is The formation of each region is directly related to the dynamic time parameters of the HSV (start-stop lag time, start-stop motion time, current adjustment time), and each corresponds to a different duty cycle range and equivalent output flow rate variation pattern: Dead zone refers to a duty cycle that is less than the upper limit of the dead zone. α 1 The region, within which the total HSV on time t on less than or equal to the normal opening / closing delay time t don Therefore, the duty cycle in this range cannot meet the minimum time required for the valve core to open, the valve core is always closed, and the equivalent output flow is always 0. Accurate identification of the dead zone can avoid the problem of no response in the digital hydraulic system (DHS) due to the duty cycle being too small. The nonlinear region includes an enabled nonlinear region and a disabled nonlinear region, with the enabled nonlinear region located at the upper limit of the dead zone. α 1 With the lower limit of the linear region α 1 + α 2 In this interval, although the duty cycle is slightly higher than that of the dead zone, it is still insufficient to allow the coil current to reach a stable and constant value. I hold Or, to allow the valve core to complete its full opening motion, the equivalent output flow rate within this range increases non-linearly with the increase of the duty cycle; the non-linear closing region is located at the upper limit of the linear region, 1- α 3 - α 4 With the lower limit of the saturation region 1- α 4Between these intervals, if the duty cycle is too large, the valve core will not close in time, and the valve core will not be able to close in time. The equivalent output flow rate will increase non-linearly with the increase of the duty cycle and approach the maximum value. The linear region refers to the region where the duty cycle is between the lower limit of the linear region. α 1 + α 2 With the upper limit of the linear region 1- α 3 - α 4 The region between these two ranges, within which the dynamic characteristics corresponding to the duty cycle can fully cover the lag time, motion time, and current adjustment time required for HSV opening and closing, the valve core can stably complete the entire process of "opening-holding-closing", and the equivalent output flow rate has a strict linear relationship with the duty cycle. This region is the core working range for DHS to achieve precise flow control. The saturation region refers to a region where the duty cycle is greater than the lower limit of the saturation region by 1- α 4 The region, within which the HSV is turned off. t off Less than or equal to the normal opening and closing lag time t doff The duty cycle cannot meet the minimum time required for the valve core to close, so the valve core is always in a fully open state, and the equivalent output flow reaches the maximum output flow of the HSV. Q max Furthermore, maintaining stability and avoiding saturation zones can prevent DHS performance fluctuations due to excess flow.

[0031] In the prediction method of this invention, only four key duty cycle boundaries need to be selected to construct the duty cycle-equivalent output flow characteristic curve of the high-speed switching valve. These four key duty cycle boundaries are the upper limit of the dead zone, etc. α 1 lower limit of the linear region α 1 + α 2 Upper limit of linear region 1- α 3 - α 4 and the lower limit of the saturation region 1- α 4 Furthermore, the duty cycle values ​​at each point are calculated using a formula based on the dynamic time parameters of the HSV, eliminating the need for traversing and testing all duty cycle points. Based on the inherent characteristics of the HSV duty cycle-equivalent output flow rate, the equivalent output flow rate remains constant at 0 within the dead zone, regardless of duty cycle changes, eliminating the need for additional flow rate testing at other points within the dead zone; within the saturation zone, the HSV remains fully open, and the equivalent output flow rate remains stable at the valve's maximum output flow rate. Qmax Only the maximum flow rate needs to be determined, without needing to traverse all duty cycle points within the saturation region. Therefore, the actual testing process can be significantly simplified: only the equivalent output flow rate corresponding to the lower limit of the linear region, the equivalent output flow rate corresponding to the upper limit of the linear region, and the maximum flow rate Qmax of the HSV need to be measured. The measured equivalent output flow rate values ​​of the upper and lower limits of the linear region are obtained as follows: the high-speed switching valve is controlled to operate stably under the condition that the duty cycle is equal to the lower limit of the linear region α1+α2 and the upper limit of the linear region 1-α3-α4, respectively, and data is collected at fixed intervals using a measuring cup. t Internal output oil volume v Based on the actual measured equivalent output flow rate The calculated maximum output flow rate Q of the high-speed switching valve is... max The method of obtaining the data is as follows: control the high-speed switching valve to operate stably under the condition of being fully open, collect the output oil volume within a fixed time period by measuring the cup, and calculate it according to the above formula.

[0032] 4) By combining the equivalent output flow rate of different duty cycle ranges with the duty cycle relationship, the duty cycle-equivalent output flow rate characteristic curve of the high-speed switching valve without nonlinear region is obtained.

[0033] When constructing the duty cycle-equivalent output flow characteristic curve, a coordinate system is established with SDR as the horizontal axis and EOF as the vertical axis. Dead zone corresponds to a duty cycle < α 1 The interval is represented by a horizontal line where the flow percentage is always 0%; the lower limit of the linear region is... α 1 + α 2 With the upper limit of the linear region 1- α 3 - α 4 The (SDR, EOF) data within the two point intervals are fitted to a straight line, specifically: ,in q For any duty cycle within the linear region, the predicted equivalent output flow rate is... q low This represents the measured equivalent output flow rate corresponding to the lower limit of the linear region. q high This represents the measured equivalent output flow rate corresponding to the upper limit of the linear region. α For any duty cycle value within the linear region, this straight line represents the duty cycle-equivalent output flow characteristic curve for the linear region; the saturation region corresponds to a duty cycle > (1- α 4 The range of HSV duty cycle is represented by a horizontal line with a constant flow percentage of 100%; ultimately, a complete and accurate HSV duty cycle-equivalent output flow characteristic curve can be quickly formed.

[0034] This invention also provides a rapid and accurate prediction system for the duty cycle-equivalent output flow characteristics of high-speed switching valves, applicable to the aforementioned rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of high-speed switching valves, comprising: Opening and closing test system: used to perform periodic opening and closing tests on the high-speed switching valve under test in single-voltage drive mode, including a data acquisition device and a measuring cup; the data acquisition device is used to acquire valve core displacement data and output dynamic time parameters. t don , t mon , t aon , t doff , t moff , t aoff The measuring cup is used to calculate the measured equivalent output flow rate; Duty cycle boundary calculation unit: used to calculate the duty cycle boundary based on the dynamic time parameters output by the start-up / shutdown test system and the set switching frequency. f Calculate the duty cycle boundary of the duty cycle-equivalent output flow characteristic region. α 1 , α 1 + α 2 1- α 3 - α 4 and 1- α 4 ; Duty cycle-equivalent output flow curve generation module: Based on the duty cycle boundary and the measured equivalent output flow value obtained from the measuring cup, it establishes the relationship between duty cycle and equivalent output flow, including dead zone, linear zone and saturation zone, and generates a duty cycle-equivalent output flow characteristic curve including dead zone, linear zone and saturation zone.

[0035] like Figure 2 The diagram illustrates an opening and closing test system that indirectly detects valve core displacement by detecting current characteristics. The system includes: The system comprises a voltage source 1, a computer 2, a current acquisition card 3, a high-speed switching valve driver 4, and a high-speed switching valve 5. The high-speed switching valve driver 4 is configured with the pulse width modulation (PWM) signal period, duty cycle (0-100%), and drive mode for driving the high-speed switching valve 5. When the valve core of the high-speed switching valve 5 moves, its coil current characteristics and valve core displacement have corresponding characteristic points. The current acquisition card 3 is used to acquire the coil current of the high-speed switching valve to indirectly detect the valve core displacement. Specific detection methods are detailed in existing technologies. For example, CN202410266937.7 discloses a solenoid valve dynamic performance detection system and method based on current characteristics, which can accurately and reliably detect the valve core's movement process, precisely identify the dynamic characteristics of the solenoid valve, and obtain the movement state of the high-speed switching valve core and the start and end times of each movement state.

[0036] This invention is applicable to multiple driving modes, its core stemming from its decoupling design from the driving modes and its capture of the essential working principle of HSV: the difference between different driving modes lies only in the voltage amplitude and application timing during the turn-on / turn-off phases. This difference only affects the rise / fall rate of the coil current, thus leading to specific numerical changes in the dynamic time parameters, but it does not change the physical essence that "dynamic time parameters determine the duty cycle region boundary"—the dead zone is always determined by the turn-on lag time (t). don The linear region must always cover the complete time of "start-up lag + start-up motion + current adjustment," while the saturation region is always dominated by the shutdown lag time (t). doff This principle, which is dominant, does not change with the driving mode. Meanwhile, the core mathematical model of the method (duty cycle boundary calculation formula) remains unchanged. , (etc.) and flow relationship (dead zone EOF=0, linear region linear fitting, saturation region EOF=Q) max All of these are based on the inherent logic of HSV valve core movement and flow output, and are independent of voltage application strategy. Under different driving modes, only the corresponding dynamic time parameters need to be obtained through periodic opening and closing tests, and the subsequent modeling and curve generation steps can be directly reused without adjusting the model structure or fitting algorithm. Therefore, it can stably adapt to various pulse width modulation (PWM) based driving modes and maintain consistent prediction accuracy and efficiency.

[0037] To verify the applicability of this method under different driving modes, the experiment used a single-voltage driving mode and a three-voltage driving mode.

[0038] This invention conducted five sets of experiments on a high-speed switching valve at a frequency of 20Hz under both single-voltage and three-voltage drive modes to verify the accuracy of the prediction method. Since oil pressure fluctuations can cause slight changes in the dynamic performance of the high-speed solenoid valve (HSV), data was sampled from five randomly selected switching cycles and averaged as the basis for prediction. The results are as follows: Table 1. Multi-cycle dynamic characteristic data under single-voltage drive method Table 2. Multi-cycle dynamic characteristic data under the three-voltage driving method Based on the average data in the table, combined with , , and The upper limit of the dead zone α1, the lower limit of the linear region α1+α2, the upper limit of the linear region 1-α3-α4, and the upper limit of the saturation region 1-α4 are shown in the table below: Table 3 Predicted Boundary Locations of Feature Regions First, verify the accuracy of the rapid prediction results for the duty cycle in the dead zone and saturation zone. Since the predicted and actual values ​​for the lower limit of the dead zone are both 0%, and the predicted and actual values ​​for the upper limit of the saturation zone are both 100%, no comparison is needed. Therefore, only compare the predicted and actual values ​​of the upper limit duty cycle of the dead zone and the lower limit duty cycle of the saturation zone, as shown in the table below (the error value is the absolute value of the difference between the predicted and actual values): Table 4. Predicted and experimental ranges of flow dead zone and saturation zone (single voltage) Table 5. Predicted and experimental ranges of flow dead zone and saturation zone (three voltages) These results demonstrate that the proposed prediction method performs exceptionally well in predicting the dead zone and saturation zone of the duty cycle-equivalent output flow curve.

[0039] To further verify the accuracy of the rapid prediction results for the linear zone, flow detection experiments were conducted under corresponding operating conditions based on the upper and lower limits of the duty cycle of the obtained linear zone control signal. This yielded the duty cycle-equivalent flow values ​​at the predicted upper and lower limits of the linear zone duty cycle, and these two points were marked on the flow curve. A straight line can then be fitted connecting these two points, serving as the prediction result for the linear flow line based on dynamic characteristics. Residual analysis of the predicted straight line value and the observed actual flow data is as follows: Figure 4 , 5 As shown.

[0040] Figure 4 and Figure 5 The upper subplot shows a comparison of experimental and fitted data for duty cycle versus equivalent output flow rate in the linear region under single-voltage drive mode and three-voltage drive mode. The horizontal axis represents the control signal duty cycle, and the vertical axis represents the percentage of equivalent output flow rate. It can be seen from the figure that the two curves almost completely overlap within the linear region. Figure 4 and Figure 5 The subplot below shows the distribution of the fitting residuals under single-voltage drive mode and three-voltage drive mode as a function of duty cycle, which more clearly shows the difference between the fitting data and the experimental data. As can be seen from the figure, the maximum flow prediction error under single-voltage mode is 0.8%, and the maximum flow prediction error under three-voltage mode is 1.3%.

[0041] Therefore, the proposed prediction method has a very small error in predicting the flow rate in the linear region of the duty cycle-equivalent output flow rate curve under both driving modes, proving that the prediction method proposed in this invention has high accuracy and engineering applicability.

[0042] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of a high-speed switching valve, characterized in that, Includes the following steps: 1) Under the selected drive mode, perform periodic opening and closing tests on the high-speed switching valve under test, record the start and end times of each movement state of the valve core and the time of coil current change, and obtain the dynamic time parameters of the high-speed switching valve; the dynamic time parameters include opening lag time, opening movement time, opening current adjustment time, closing lag time, closing movement time, and closing current adjustment time. 2) Based on the obtained dynamic time parameters and opening / closing cycle, calculate the duty cycle boundaries of different intervals in the duty cycle-equivalent output flow characteristic of the high-speed switching valve under test. The duty cycle boundaries include the upper limit of the dead zone. α 1 lower limit of the linear region α 1 + α 2 Upper limit of linear region 1- α 3 - α 4 and the lower limit of the saturation region 1- α 4 The areas between the upper limit of the dead zone and the lower limit of the linear zone, and between the upper limit of the linear zone and the lower limit of the saturation zone, are all nonlinear regions. 3) Establish the duty cycle-flow characteristic relationship based on the measured equivalent output flow rate: when the duty cycle is in the dead zone, determine the relationship that the equivalent output flow rate is always 0; when the duty cycle is in the linear zone, establish the linear fitting relationship based on the measured equivalent output flow rate values ​​of the upper and lower limits of the linear zone; when the duty cycle is in the saturation zone, determine the relationship that the equivalent output flow rate is always 100%. 4) Combine the equivalent output flow rate and duty cycle relationship for different duty cycle intervals, and establish a coordinate system with duty cycle as the horizontal axis and equivalent output flow rate as the vertical axis. The dead zone is represented by a horizontal line where the equivalent output flow rate is always 0, the linear zone is represented by a linear fitting line, and the saturation zone is represented by a horizontal line where the equivalent output flow rate is always 100%. This yields the duty cycle-equivalent output flow rate characteristic curve of the high-speed switching valve that does not include the nonlinear zone. The duty cycle-equivalent output flow rate characteristic curve is the relationship curve between the duty cycle and the equivalent output flow rate at that duty cycle.

2. The method according to claim 1, characterized in that, Step 1) The selected drive mode divides one opening and closing cycle of the high-speed switching valve into an opening phase and a closing phase: during the opening phase, a preset voltage is applied to provide sufficient electromagnetic force for the valve core to open; During the shutdown phase, the voltage source applies zero voltage or reverse voltage to the high-speed switching valve coil, causing the valve core to be driven to reset and close by spring force.

3. The method according to claim 2, characterized in that, Step 1) The dynamic time parameters are obtained through direct detection, specifically: a laser displacement sensor is installed on the high-speed switching valve, and the valve core displacement curve is collected in real time by the laser displacement sensor. The valve core start-up time, full opening time, start-closing time and full closing time are determined according to the abrupt change point of the slope of the displacement curve.

4. The method according to claim 2, characterized in that, Step 1) The dynamic time parameters are obtained through indirect detection. Specifically, the current curve of the high-speed switching valve coil is acquired by a current acquisition card. The corresponding feature points of the coil current characteristics and valve core displacement are used to obtain the valve core start-opening time, full-opening time, start-closing time, and full-closing time.

5. The method according to claim 2, characterized in that, The dynamic time parameter in step 1) is calculated as follows: Enable lag time t don The difference between the moment the valve core begins to open and the initial moment of the opening phase; Start your workout time t mon The difference between the moment the valve core is fully open and the moment it begins to open; Turn-on current adjustment time t aon The difference between the moment when the coil current reaches a stable and constant value during the opening phase of a high-speed switching valve and the moment when the valve core is fully open. Closure time t doff The difference between the moment the valve core begins to close and the initial moment of the closing phase; Turn off exercise time t moff The difference between the moment the valve core is fully closed and the moment it begins to close; Current adjustment time off t aoff The difference between the moment when the coil current decays to zero during the closing phase of a high-speed switching valve and the moment when the valve core is completely closed.

6. The method according to claim 1, characterized in that, Step 1) The periodic opening and closing test shall last for at least 5 consecutive opening and closing cycles. When obtaining the dynamic time parameters of the high-speed switching valve, the average value of the parameter values ​​of the 5 consecutive opening and closing cycles shall be taken to offset the influence of oil pressure fluctuations on the dynamic performance of the high-speed switching valve.

7. The method according to claim 1, characterized in that, Step 3) The measured equivalent output flow rate values ​​of the upper and lower limits of the linear region are obtained as follows: the high-speed switching valve is controlled to operate stably under the condition that the duty cycle is equal to the lower limit of the linear region α1+α2 and the upper limit of the linear region 1-α3-α4 respectively, and the flow rate is collected at fixed time by measuring cup. t Internal output oil volume v Based on the actual measured equivalent output flow rate Calculated.

8. The method according to claim 1, characterized in that, The linear fitting relationship in step 3) is specifically as follows: ,in q For any duty cycle within the linear region, the predicted equivalent output flow rate is... q low This represents the measured equivalent output flow rate corresponding to the lower limit of the linear region. q high This represents the measured equivalent output flow rate corresponding to the upper limit of the linear region. α This represents any duty cycle value within the linear region.

9. The method according to claim 1, characterized in that, The selected driving modes include single-voltage driving mode, three-voltage driving mode, and preloaded voltage driving mode.

10. A rapid and accurate prediction system for the duty cycle-equivalent output flow characteristics of a high-speed switching valve, applicable to the rapid and accurate prediction method for the duty cycle-equivalent output flow characteristics of a high-speed switching valve as described in any one of claims 1-9, characterized in that... include: Opening and closing test system: used to perform periodic opening and closing tests on the high-speed switching valve under test in single voltage drive mode, including a data acquisition device and a measuring cup; The data acquisition device is used to acquire valve core displacement data and output dynamic time parameters. t don , t mon , t aon , t doff , t moff , t aoff The measuring cup is used to calculate the measured equivalent output flow rate; Duty cycle boundary calculation unit: used to calculate the duty cycle boundary based on the dynamic time parameters output by the start-up / shutdown test system and the set switching frequency. f Calculate the duty cycle boundary of the duty cycle-equivalent output flow characteristic region. α 1 , α 1 + α 2 1- α 3 - α 4 and 1- α 4 ; Duty cycle-equivalent output flow curve generation module: Based on the duty cycle boundary and the measured equivalent output flow value obtained from the measuring cup, it establishes the relationship between duty cycle and equivalent output flow, including dead zone, linear zone and saturation zone, and generates a duty cycle-equivalent output flow characteristic curve including dead zone, linear zone and saturation zone.

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