A test system and method for dynamic characteristics of high-speed on-off valve

Abstract

The application relates to a high-speed switch valve dynamic characteristic test system, which comprises a high-speed switch valve, a driving control module, a hydraulic control module, a data acquisition module and an upper computer; the high-speed switch valve is connected with the driving control module, the hydraulic control module and the data acquisition module respectively; the upper computer is connected with the driving control module and the data acquisition module respectively; the driving control module comprises a controller, a logic module and a driver which are connected in sequence; the controller is further connected with the upper computer; the hydraulic control module comprises a pressure source and a test valve block; the data acquisition module comprises a data collector, a current sensor, a flow sensor and a pressure sensor; the current sensor acquires the current between the driver and the high-speed switch valve; the oil inlet is provided with the flow sensor and the pressure sensor; the data collector is connected with the current sensor, the flow sensor, the pressure sensor and the upper computer respectively. The application effectively improves the test efficiency and precision of the high-speed switch valve dynamic characteristics.

Description

Technical Field

[0001] This invention relates to the field of hydraulic component testing technology, and specifically to a testing system and method for the dynamic characteristics of a high-speed switching valve. Background Technology

[0002] Digital hydraulic technology has become a pioneer in "Hydraulic Industry 4.0" and "Intelligent Digital Hydraulics," while intelligent manufacturing requires the development of integrated, cross-functional, miniaturized, lightweight, high-performance hydraulic control components adapted to electro-hydraulic integration. High-speed switching valves are compact in structure, have short switching times, fast reversing frequencies, low cost, and are insensitive to oil contamination. They can directly achieve digital quantity control, facilitating hydraulic digitization and high reliability. Furthermore, high-speed switching valves have very broad application prospects in many fields, especially in aerospace and oil extraction operations where the complex and variable environments place extremely demanding requirements on hydraulic components. High-speed switching valves can meet the needs of launch vehicle thrust vector control and intelligent drilling and completion systems for oil and gas extraction.

[0003] High-speed switching valves are key to the development of digital hydraulic technology. One of their most important characteristics is high-frequency response, meaning high-frequency switching and high-speed response. Ideally, a high-speed switching valve opened by an electromagnet attracting the valve core will, when the electromagnet is excited by a high-frequency PWM signal, cause the valve core to switch synchronously at high frequency, controlling the high-frequency pulse flow output at the valve port. Therefore, adjusting the frequency and duty cycle of the PWM signal can control the average flow output at the valve port, further achieving precise control of the electro-hydraulic system. However, due to the inductive characteristics of the electromagnet coil, there is a delay in the electromagnetic force reaching the critical opening point, resulting in an electromagnetic response to the valve core switching; and due to the inertia of the valve core movement, the switching action has a mechanical response.

[0004] The response time of the valve core switch leads to: (1) When the PWM signal frequency is constant, the valve core cannot open normally under low duty cycle, and the average output flow is almost 0; under high duty cycle, the valve port is almost continuously fully open, and the average output flow quickly approaches the maximum value; in the flow-duty cycle curve, there are dead zones and saturation zones where the flow is uncontrollable; (2) When the PWM signal duty cycle is constant: at high frequency, there is a situation where the electromagnetic force cannot reach the critical opening electromagnetic force, or the electromagnetic force reaches the critical opening value, but the valve core cannot be fully opened, and the high-speed switching valve cannot work normally; at low frequency, the flow pulse is too large, and the output flow cannot be controlled.

[0005] To achieve precise control of the electro-hydraulic system, it is necessary to test the dynamic characteristics of the high-speed switching valve, that is, to change the control parameters in the electro-hydraulic system and test the response changes of the high-speed switching valve. Theoretically, the electromagnetic response time of the high-speed switching valve is the time it takes for the electromagnetic force to reach the critical electromagnetic force from 0; the mechanical response time is the time it takes for the valve core to move from one extreme position to another extreme position. The existing testing methods for the dynamic characteristics of high-speed switching valves mainly include: (1) using force sensors and displacement sensors to measure the electromagnetic force and valve core displacement in actual working conditions to directly obtain the response time; (2) using the measurement of valve port pressure changes to indirectly obtain the response time.

[0006] Existing technologies are helpful for testing the dynamic characteristics of high-speed switching valves, but they still have some shortcomings and other limitations:

[0007] (1) The method of directly testing the response time by using force sensors and displacement sensors to measure the electromagnetic force and valve core displacement of high-speed switching valves is relatively accurate, but it still has shortcomings. Sensors are divided into contact and non-contact types. Contact sensors, such as resistive and piezoelectric sensors, require auxiliary measuring devices to be installed on the valve core when measuring force or displacement. For example, resistive sensors require the addition of a sliding plate, and piezoelectric sensors require the addition of a piezoelectric crystal. This means that contact sensors can only be used in the testing of non-compact high-speed switching valves and require certain tooling conditions. Non-contact sensors, such as inductive and laser sensors, can be used in compact structures, but those with higher measurement accuracy are generally more sensitive to changes in the external environment, have poor anti-interference ability, require higher tooling conditions, and are expensive, which increases the testing cost.

[0008] (2) The method of indirectly obtaining the response time of a high-speed switching valve by measuring the pressure change at the valve port involves installing a pressure test chamber at the valve port. When the high-speed switching valve opens and closes, the pressure changes significantly in a very short time. By detecting the instantaneous change in the pressure test chamber, the change in valve core position is indirectly tested. This method has low requirements for tooling conditions, but since the pressure only changes after the valve port opens, the pressure change inevitably lags behind the change in valve core displacement, resulting in low test accuracy. Moreover, this method can only obtain the mechanical response time of the high-speed switching valve by testing the change in valve core position, and cannot obtain its electromagnetic response time. In addition, under more complex or extreme operating conditions, the problem of pressure signal lag is more prominent, and there are even cases where the response time cannot be tested. Summary of the Invention

[0009] In view of this, the purpose of the present invention is to provide a testing system and method for the dynamic characteristics of high-speed switching valves, in order to solve the above-mentioned problems.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] A testing system for the dynamic characteristics of a high-speed switching valve includes a high-speed switching valve, a drive control module, a hydraulic control module, a data acquisition module, and a host computer. The high-speed switching valve is connected to the drive control module, the hydraulic control module, and the data acquisition module respectively. The host computer is connected to the drive control module and the data acquisition module respectively. The drive control module includes a controller, a logic module, and a driver connected in sequence. The controller is also connected to the host computer. The hydraulic control module includes a pressure source and a test valve block. The data acquisition module includes a data acquisition unit, a current sensor, a flow sensor, and a pressure sensor. The current sensor acquires the current between the driver and the high-speed switching valve. A flow sensor and a pressure sensor are installed at the oil inlet. The data acquisition unit is connected to the current sensor, the flow sensor, the pressure sensor, and the host computer respectively.

[0012] Furthermore, the driver has multiple backup signal output channels for use in high-speed switching valves driven by single, dual, and multiple electromagnets. The driver is powered by an adjustable voltage source and outputs analog control signals of different amplitudes.

[0013] Furthermore, the pressure source is provided by a variable pump with adjustable oil supply pressure, which has two modes: static adjustment and dynamic adjustment, that is, pressure adjustment is performed when the high-speed switching valve is not working and when it is working.

[0014] Furthermore, the test valve block has multiple sets of inlets and outlets to test a single high-speed switching valve as needed, or to test multiple high-speed switching valves simultaneously.

[0015] A method for testing the dynamic characteristics of a high-speed switching valve includes the following steps:

[0016] Step S1: In the host computer, configure each signal channel that needs to be collected, and set the timing mode, i.e., sampling mode, sampling rate and number of samples to be read;

[0017] Step S2: On the host computer, write the conversion rates of each signal and perform signal zeroing;

[0018] Step S3: Set the control parameters for each system, including: pressure source size, external load size, frequency of excitation signal, duty cycle, amplitude, positive, negative, and zero amplitude, and output sequence;

[0019] Step S4: First, start data acquisition, then run the drive control program in the host computer;

[0020] Step S5: Once the system has stabilized, first stop the drive control program, then end the data acquisition.

[0021] Step S6: If the data is saved normally, analyze the data to obtain the response times of the high-speed switching valve and further analyze its dynamic characteristics.

[0022] Furthermore, the response times of the high-speed switching valve include electromagnetic response time, mechanical response time, pressure response time, and flow response time:

[0023] (1) The electromagnetic response time and mechanical response time of the high-speed switching valve are obtained by analyzing the current of the electromagnet coil; during the current rise process, the time for the current to rise from 0 to the first inflection point is the electromagnetic response time; the time for the current to fall from the first inflection point to the second inflection point is the mechanical response time.

[0024] (2) The pressure response time of the high-speed switching valve is obtained by comparing and analyzing the pressure before or after the valve with the current of the electromagnet coil; the pressure response time is the time from the second inflection point during the rise of the current to the time when the pressure begins to change in a second-order oscillating manner.

[0025] (3) The flow response time of the high-speed switching valve is obtained by comparing and analyzing the flow rate and the current of the electromagnet coil; the flow response time is the time from the second inflection point during the current rise to the time when the flow rate begins to change in a sinusoidal manner.

[0026] Furthermore, the current inflection point is generated by the change in inductance of the electromagnet coil. In order to obtain a clear current signal inflection point under high-frequency excitation signal, a high-power resistor is directly connected in series with the electromagnet, and the voltage signal at both ends of the resistor is collected to replace the current sensor.

[0027] Furthermore, the resistance value of the high-power resistor and its maximum power By excitation signal amplitude and the internal resistance of the electromagnet coil It can be concluded that; , .

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] 1. This invention indirectly obtains the response time by utilizing the current signal of an electromagnet coil, avoiding the direct measurement of the electromagnetic force and valve core displacement of a high-speed switching valve. It eliminates the need to provide additional tooling conditions for force or displacement sensors in the system, and is applicable to most high-speed switching valves with compact structures. While ensuring the reliability of the test results, it simplifies the test system and reduces the test cost.

[0030] 2. This invention utilizes the principle that the inflection point of the current in a high-speed switching valve corresponds to the response of the electromagnet coil. The measured response time has almost no lag problem, greatly improving the testing accuracy. At the same time, it can obtain not only the mechanical response of the high-speed switching valve, but also its electromagnetic response time. In addition, to avoid the problem of difficulty in identifying the current inflection point under complex or extreme operating conditions, this invention directly uses a resistor connected in series with the electromagnet to measure the voltage across its two ends and convert it into current, replacing the method of measuring current with a sensor, further improving testing accuracy and reducing testing costs.

[0031] 3. This invention effectively improves testing efficiency and accuracy. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the test system composition according to an embodiment of the present invention.

[0033] In the diagram: 1-1, Host computer drive control program; 1-2, Controller; 1-3, Logic module; 1-4, Driver; 1-5, Adjustable DC switching power supply; 2-1, Pump station; 2-2, Test valve block; 2-3, Throttling valve; 2-4, Oil tank; 3-1, High-power resistor R1; 3-2, High-power resistor R2; 3-3, Voltage sensor 1; 3-4, Voltage sensor 2; 3-5, Pressure sensor 1; 3-6, Pressure sensor 2; 3-7, Pressure gauge 1; 3-8, Pressure gauge 2; 3-9, Flow meter; 3-10, Data acquisition unit; 3-11, A / D signal conversion module; 3-12, Host computer data display and acquisition program; 4, Dual electromagnet high-speed switching valve.

[0034] Figure 2 This is a schematic diagram of the operation method of the test system according to an embodiment of the present invention.

[0035] Figure 3 This is a diagram showing the effect of measuring the current of an electromagnet coil using a high-power resistor in an embodiment of the present invention.

[0036] Figures 4-6 This is a schematic diagram of the measured response times of the high-speed switching valve in an embodiment of the present invention. Detailed Implementation

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0038] Please refer to Figure 1This invention provides a testing system for the dynamic characteristics of a high-speed switching valve, comprising a high-speed switching valve, a drive control module, a hydraulic control module, a data acquisition module, and a host computer; the high-speed switching valve is connected to the drive control module, the hydraulic control module, and the data acquisition module respectively; the host computer is connected to the drive control module and the data acquisition module respectively; the drive control module includes a controller, a logic module, and a driver connected in sequence; the controller is also connected to the host computer; the hydraulic control module includes a pressure source and a test valve block; the data acquisition module includes a data acquisition unit, a current sensor, a flow sensor, and a pressure sensor; the current sensor acquires the current between the driver and the high-speed switching valve; a flow sensor and a pressure sensor are installed at the oil inlet; the data acquisition unit is connected to the current sensor, the flow sensor, the pressure sensor, and the host computer respectively.

[0039] In this embodiment, the high-speed switching valve adopts a two-position, two-way dual-electromagnetic high-speed switching valve with a valve core stroke of 0.25mm. Its working mode is as follows: when electromagnets A and B are energized, they attract the valve core to the corresponding iron core. When electromagnet A is working, the valve is opened, and when electromagnet B is working, the valve is closed. The drive control module includes a host computer drive control program, a controller, a logic module, a driver, and an adjustable DC power supply. The hydraulic control module includes a pump station, a test valve block, a throttle valve, and an oil tank. The data acquisition module includes high-power resistors R1 and R2, voltage sensors 1 and 2, pressure sensors 1 and 2, pressure gauges 1 and 2, a flow meter, a data acquisition unit, an A / D signal conversion module, and a host computer data display and acquisition program.

[0040] In this example, the host computer drive control program is connected to the controller input and sends digital control signals to the controller according to the edited instructions; the controller output is connected to the logic module input, and the logic module converts the input digital control signals into analog control signals and outputs them to the driver signal input; the adjustable switching power supply can output excitation voltages of different amplitudes to the driver power input; the driver uses dual-channel output to amplify the input analog control signals to an amplitude of The excitation signals U1 and U2 are output from the output terminals MA and MB to the electromagnets A and B of the high-speed switching valve, respectively. By editing the instructions and adjusting the output amplitude, the frequency, duty cycle, amplitude, positive, negative, zero amplitude and output sequence of the excitation signals U1 and U2 can be adjusted and combined to simulate various actual working modes of the high-speed switching valve.

[0041] In this example, the pump station is connected to the oil inlet P1 of the test valve block, and the pressure source is adjusted and output to the hydraulic circuit. The pressure source has two adjustment methods: static adjustment and dynamic adjustment. That is, the pressure is adjusted when the high-speed switching valve is not working and when it is working. The adjustment range is 0-50MPa. The oil return port T1 of the test valve block is connected to the oil tank after passing through the throttle valve. Adjusting the opening of the throttle valve simulates the size of the external load, so that the pressure difference before and after the high-speed switching valve changes. By adjusting the pressure source and the opening of the throttle valve, various different working conditions can be provided for the high-speed switching valve.

[0042] In this example, high-power resistors R1 and R2 are connected in series with electromagnets A and B of the high-speed switching valve, respectively, converting the coil current of electromagnets A and B into voltage signals across resistors R1 and R2; voltage sensors 1 and 2 are connected to the output terminals MA and MB of the driver, respectively, converting the large-range input voltage into a small-range voltage signal; pressure sensors 1 and 2 are connected in parallel with pressure gauges 1 and 2 to the control ports K1 and K2 of the test valve block, respectively, converting the input pressure signals before and after the valve into voltage signals; the flow meter includes a flow acquisition and digital display module, with the flow acquisition module connected in series between the pump station and the oil inlet P1 of the test valve block, displaying the hydraulic circuit flow... The signal is converted into a pulse signal and output to the flow display module; the flow display module can read the flow value in real time and convert the input pulse signal into a voltage signal; the data acquisition unit receives the above voltage signals to the signal input terminals ai1~ai7 respectively, and outputs them to the A / D signal conversion module to convert them into digital signals, and finally outputs them to the host computer data display and acquisition program; the host computer data display and acquisition program reads each data and converts it into dynamic values ​​and waveforms, which are displayed as current 1, 2, voltage 1, 2, inlet pressure, outlet pressure and flow rate respectively. The data can be further saved as graph and table files for analysis of the dynamic characteristics of high-speed switching valves.

[0043] Figure 2 It schematically represents Figure 1 The operation method flow of the test system shown in a specific embodiment.

[0044] In this embodiment, the operation process of a high-speed switch dynamic characteristic testing system specifically includes the following steps:

[0045] Step 1: In the host computer data display and acquisition program, configure the signal channels for current 1 and 2, voltage 1 and 2, pre-valve and post-valve pressure, and flow rate respectively, set the sampling mode, and the system provides the default sampling rate and the number of samples to be read; From the second test onwards, it is necessary to determine whether the sampling rate needs to be changed and selected based on the frequency of the excitation signals U1 and U2, and further determine whether the buffer needs to be increased. If the buffer is increased, then set a new number of samples to be read according to the formula: buffer = number of samples to be read * number of acquisition channels.

[0046] Step 2: Run the host computer data display and acquisition program, and write the filename of the data to be saved in this test; after clicking "Start", the host computer data display and acquisition program will save the newly named empty tdms file in the program's path; since it cannot overwrite the old file, starting from the second test, repeat the test with the same name. Before clicking "Start", you must remove the old file with the same name in the file saving path.

[0047] Step 3: Turn on the power to supply power to each signal acquisition element and driver: After powering on, the host computer data display and acquisition program display signals that may have noise interference, but since there is no signal input, zeroing is required; after the first test or replacement of the signal acquisition element causing a change in the conversion ratio, the current signal conversion ratio must be written first, and then the approximate value of the signal noise interference must be written to the corresponding "offset" position; from the second test onwards, if interference still exists, the "offset" can be reset.

[0048] Step 4: Start the pump station and set the pressure source size; adjust the throttle valve opening and set the external load size; edit the instructions in the host computer drive control program to define the frequency, duty cycle, amplitude (positive, negative, zero) and output sequence of the excitation signal; set the output amplitude of the adjustable switching power supply.

[0049] Step 5: First, click "Data Acquisition" in the host computer data display and acquisition program. The program will automatically write dynamic data to the newly named empty tdms file according to the channel order. Then, upload the drive control program to the controller to control the high-speed switching valve to work according to the edited instructions. The signals will change rapidly accordingly.

[0050] Step 6: Once the flow rate display module readings have stabilized, first press the controller reset button to stop the current drive control program; then click "Data Acquisition" again to stop writing dynamic data of each channel to the tdms file and end the data acquisition.

[0051] Step 7: Click "View Data" in the data acquisition program. In the pop-up "Open File" window, find the TDMS file you just saved and open it. In the TDMS file viewer, check whether the table and graphic data saved for each channel have not been saved correctly. If so, return to step 2 and re-perform the acquisition.

[0052] Step 8: If the file is saved normally, the response time of each stage of the high-speed switching valve opening and closing can be obtained by analyzing the data; if it is necessary to continue the next round of testing, return to step 1 and adjust the control parameters of step 4 as needed; if the test is not to continue, turn off the power and the pump station.

[0053] Figure 3 This schematically illustrates the effect of using a high-power resistor to measure the current in an electromagnet coil.

[0054] In this embodiment, Figure 3 The figure shows a comparison of the single-sided electromagnet coil current and the time domain of the excitation signal under the following conditions: a pressure source of 20 MPa, a valve port pressure difference of 5 MPa, a PWM excitation signal amplitude ranging from positive 24V to negative 24V and then to 0, a positive duty cycle of 0.5, a negative duty cycle of 0.1, and a frequency accumulating from 0 to 500 Hz. Even under high-frequency and complex operating conditions, a high-precision current curve can still be measured, and the inflection points during its changes are clearly defined.

[0055] Figure 4 The diagram illustrates the measured response times of the high-speed switching valve.

[0056] In this embodiment, Figure 4 The high-speed switching valve shown operates under the following conditions: pressure source 7MPa, valve port differential pressure 1MPa, PWM excitation signal duty cycle 0.5, frequency 100Hz. Wherein:

[0057] Figure 4 The diagram schematically illustrates the electromagnetic and mechanical response times during the opening and closing phases of a high-speed switching valve.

[0058] In this embodiment, Figure 4 The figure shows the time-domain current curves of coils A and B of electromagnets. During the current rise process, the time it takes for the current to rise from 0 to the first inflection point is the electromagnetic response time during the on and off phases, respectively; the time it takes for the current to fall from the first inflection point to the second inflection point is the mechanical response time during the on and off phases, respectively.

[0059] Figure 5 The diagram illustrates the measured pressure response time during the opening and closing phases of the high-speed switching valve.

[0060] In this embodiment, Figure 5 The figure shows the time-domain curves of the current in the coils of electromagnets A and B and the pressure before the valve. The time from the second inflection point during the rise of currents 1 and 2 to the time when the pressure begins to change in a positive and negative second-order oscillatory pattern, respectively, represents the pressure response time during the opening and closing phases.

[0061] Figure 6 The diagram illustrates the flow response time during the opening and closing phases of the measured high-speed switching valve.

[0062] In this embodiment, Figure 6 The figure shows the time-domain curves of current and flow rate in coils A and B of electromagnets. The time from the second inflection point during the rise of currents 1 and 2 to the time when the flow rate begins to change in a sinusoidal pattern of first rising and then falling, and first falling and then rising, respectively, represents the flow rate response time during the on-off and off-off phases.

[0063] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method of testing the dynamic characteristics of a high speed on-off valve, characterized by, The testing system employed includes a high-speed switching valve, a drive control module, a hydraulic control module, a data acquisition module, and a host computer. The high-speed switching valve is connected to the drive control module, the hydraulic control module, and the data acquisition module, respectively. The host computer is connected to the drive control module and the data acquisition module, respectively. The drive control module includes a controller, a logic module, and a driver connected in sequence. The controller is also connected to the host computer. The hydraulic control module includes a pressure source and a test valve block. The data acquisition module includes a data acquisition unit, a current sensor, a flow sensor, and a pressure sensor. The current sensor acquires the current between the driver and the high-speed switching valve. The oil inlet of the test valve block is equipped with a flow sensor and a pressure sensor. The data acquisition unit is connected to the current sensor, flow sensor, pressure sensor and host computer respectively; The testing method of the testing system includes the following steps: Step S1: In the host computer, configure each signal channel that needs to be collected, and set the timing mode, i.e., sampling mode, sampling rate and number of samples to be read; Step S2: On the host computer, write the conversion rates of each signal and perform signal zeroing; Step S3: Set the control parameters for each system, including: pressure source size, external load size, frequency of excitation signal, duty cycle, amplitude, positive, negative, and zero amplitude, and output sequence; Step S4: First, start data acquisition, then run the drive control program in the host computer; Step S5: Once the system has stabilized, first stop the drive control program, then end the data acquisition. Step S6: If the data is saved normally, analyze the data to obtain the response times of the high-speed switching valve, and further analyze its dynamic characteristics; The response times of the high-speed switching valve include electromagnetic response time, mechanical response time, pressure response time, and flow response time: (1) The electromagnetic response time and mechanical response time of the high-speed switching valve are obtained by analyzing the current of the electromagnet coil; during the current rise process, the time for the current to rise from 0 to the first inflection point is the electromagnetic response time; the time for the current to fall from the first inflection point to the second inflection point is the mechanical response time. (2) The pressure response time of the high-speed switching valve is obtained by comparing and analyzing the pressure before or after the valve with the current of the electromagnet coil; the pressure response time is the time from the second inflection point during the rise of the current to the time when the pressure begins to change in a second-order oscillating manner. (3) The flow response time of the high-speed switching valve is obtained by comparing and analyzing the flow rate and the current of the electromagnet coil; the flow response time is the time from the second inflection point during the current rise to the time when the flow rate begins to change in a sinusoidal manner.

2. The method of claim 1, wherein The driver has multiple backup signal output channels for use in high-speed switching valves driven by single, dual, and multiple electromagnets. The driver is powered by an adjustable voltage source and outputs analog control signals of different amplitudes.

3. The method of claim 1, wherein the high-speed on-off valve is a solenoid valve. The pressure source is provided by a variable pump with adjustable oil supply pressure, and there are two modes: static regulation and dynamic regulation, that is, pressure regulation is performed when the high-speed switching valve is not working and when it is working.

4. The method of claim 1, wherein the high-speed on-off valve is a solenoid valve. The test valve block has multiple sets of inlets and outlets to test a single high-speed switching valve as needed, or to test multiple high-speed switching valves simultaneously.

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