Proportional valve dynamic characteristic detection system

Abstract

The invention discloses a proportional valve dynamic characteristic detection system, relates to detection of variable mechanism testing devices, and belongs to the field of testing, the proportional valve dynamic characteristic detection system comprises an upper computer, a to-be-tested proportional valve and a metal containing cavity, the metal containing cavity is internally provided with a through flow channel, the inlet of the flow channel is connected with the to-be-tested proportional valve, the outlet of the flow channel is connected with a throttling orifice, and the throttling orifice is connected with the upper computer. A pressure sensor matched with the flow channel is arranged in the metal containing cavity, the pressure sensor is in electric signal connection with an oscilloscope, and the upper computer is in electric signal connection with the proportional valve to be tested. Compared with the prior art, the dynamic response of the proportional valve can be accurately detected in real time through the cooperation of the pressure sensor and the oscilloscope in the system. Meanwhile, simulation analysis helps to determine the size of the rear-end cavity and the size of the throttling orifice, and it is ensured that the system is compact and has high measurement precision and adaptability. The whole testing device is convenient to install, simple in structure and capable of meeting testing requirements of proportional valves of different specifications.

Description

Technical Field

[0001] The invention relates to the detection of a variable mechanism testing device, belongs to the testing field, and particularly relates to the dynamic characteristic detection of a proportional valve. Background Art

[0002] A proportional valve is a hydraulic valve that converts an input electrical signal into force or displacement in proportion, thereby continuously controlling parameters such as pressure and flow. When an electrical signal is input into its electromagnetic system, an electromagnetic thrust proportional to the current is generated, which controls the corresponding components and valve core, so that the valve core balances the pressure set by the system, and then makes the system pressure proportional to the electrical signal. If the input electrical signal changes proportionally or in a certain program, the parameters of the system will also change accordingly. The proportional valve consists of a DC proportional solenoid and a hydraulic valve. Among them, the DC proportional solenoid is different from the solenoid used in general solenoid valves. The use of a proportional solenoid can obtain a displacement output and suction output proportional to the given current. The hydraulic valve part is not much different from a general hydraulic valve.

[0003] In fluid control systems, proportional valves are widely used as a key component for precise control of pressure, flow and liquid level. The performance of proportional valves directly affects the stability and response speed of the entire system, so the test of the dynamic characteristics of proportional valves is particularly important.

[0004] The main contents of the proportional valve dynamic characteristics test include the proportional valve's response time under different input signals (such as step signals or sine wave signals), valve core displacement speed, and system stability. Specifically, the dynamic characteristics test evaluates the delay time between the proportional valve receiving the input signal and executing the valve core switch action, the system's response speed and accuracy. These data play a key role in optimizing the fluid system's response speed, reducing the system's overshoot and oscillation, and improving control accuracy.

[0005] The importance of dynamic characteristics testing lies in: ① Ensuring the stability of system performance: The response speed of the proportional valve directly affects the control accuracy and stability of the entire system. In the field of automation and high-precision control, slow or too fast response time of the proportional valve will lead to error accumulation in the control system, and even cause system oscillation or failure. ② Adapt to high-frequency response requirements: With the increase in the complexity of industrial automation systems, more and more scenarios require proportional valves to have a higher natural frequency (usually above 100Hz) in order to cope with rapid changes in complex environments. Traditional proportional valve dynamic characteristics test systems often cannot effectively cope with such high-frequency response requirements, so more efficient testing methods are urgently needed. ③ Optimize product development processes: Through dynamic characteristics testing, R&D personnel can accurately understand the core parameters of the proportional valve, such as the mechanical response time and electromagnetic response time, thereby improving the design of the proportional valve and improving the performance and reliability of the product.

[0006] The difficulty of dynamic characteristics testing is mainly reflected in the following aspects: ① Accurate detection of high-frequency signals: At high frequencies (such as natural frequencies greater than 100Hz), the response speed of the proportional valve is extremely high. Traditional testing methods (such as orifice flowmeters) have slow response speeds and are difficult to capture instantaneous valve core movements, making detection difficult and inaccurate. ② Influence of environmental factors: Signal detection during the proportional valve test is susceptible to interference from the external environment (such as temperature, pressure fluctuations, etc.), especially during dynamic testing. Slight changes in pressure in the chamber will also affect the accuracy of the test results. Therefore, the test system must have good anti-interference capabilities. ③ Coupling of multivariable parameters: The dynamic characteristics test of the proportional valve involves multiple coupling variables, including the displacement speed of the valve core, pressure fluctuations, physical properties of the medium, etc. The mutual influence between these parameters complicates the test and increases the difficulty of test system design and parameter adjustment.

[0007] In the prior art, the methods for measuring the dynamic characteristics of proportional valves can be mainly divided into the following categories: 1. Direct measurement of valve core displacement: Directly measure the displacement change of the proportional valve core during operation through a displacement sensor (such as a laser displacement sensor, etc.), thereby reflecting its dynamic characteristics. The displacement data of the valve core can be used to infer the valve opening, response time, etc. Disadvantages: Destructive; in most cases, the valve core of the proportional valve is located inside and closed, so in order to measure its displacement, it is often necessary to physically modify the valve, such as opening a hole or adding a sensor device. This modification usually affects the inherent dynamic characteristics of the proportional valve, making the measurement result inconsistent with the actual working state.

[0008] External devices affect the dynamic characteristics of the valve; adding external sensors or performing displacement detection by modifying the valve core structure will increase the mass of the valve core or change its stress conditions, affecting the dynamic response and true characteristics of the valve, resulting in distorted measurement results.

[0009] 2. Connect a fixed cavity to measure the pressure change of the fixed cavity: This method installs a fixed cavity at the outlet of the proportional valve to monitor the change of the pressure in the cavity in real time as the proportional valve moves, so as to infer the displacement and opening of the valve core. This method mainly uses a pressure sensor to capture the pressure fluctuation when the valve is opened or closed.

[0010] Disadvantages: Unable to test complex dynamic processes; the design of the fixed chamber means that this method can only measure the response time and cannot fully evaluate the dynamic characteristics of the proportional valve. Measuring hysteresis: Since the change of the chamber pressure lags behind the actual movement of the valve core, the measurement result cannot accurately reflect the dynamic process of the proportional valve, especially for proportional valves with higher frequencies, the pressure change lag will be more obvious, affecting the accuracy of the test.

[0011] 3. Direct flow measurement: Use a flowmeter to measure the change in the flow rate at the outlet of the proportional valve, thereby inferring the displacement of the valve core and the dynamic characteristics of the proportional valve. The flow rate change is usually directly related to the opening of the valve core, so the flowmeter can reflect the dynamic response of the proportional valve. Disadvantages: The flowmeter has a slow response speed; most flowmeters (such as orifice flowmeters or turbine flowmeters) have a slow response speed in dynamic testing, especially when testing proportional valves with higher frequencies. The sampling frequency of the flowmeter is not enough to capture the rapidly changing flow signal, resulting in inaccurate measurement results. Unable to test high-frequency dynamic characteristics; due to the low frequency response of the flowmeter, it cannot accurately reflect the dynamic characteristics of the proportional valve under high-frequency working conditions. Therefore, this method is suitable for proportional valves with low-frequency response, but it has limitations for measuring the performance of high-frequency proportional valves.

[0012] In summary, although the existing proportional valve dynamic characteristics detection methods have their own applications, they all have obvious limitations. Directly measuring the displacement of the valve core requires destroying the valve structure, which affects the measurement accuracy; the pressure measurement method of the fixed cavity cannot fully evaluate the dynamic process opening of the proportional valve; the method of directly measuring the flow rate has a slow response speed and cannot meet the requirements of high-frequency measurement. Therefore, the existing detection methods need to be improved in terms of accuracy, practicality and adaptability. Summary of the invention

[0013] In view of the deficiencies in the prior art, the present invention provides a proportional valve dynamic characteristics detection system. In the system of the present application, the cooperation between the pressure sensor and the oscilloscope enables the dynamic response of the proportional valve to be detected in real time and accurately. At the same time, simulation analysis helps determine the size of the rear-end chamber and the throttling orifice plate, ensuring that the system is compact and has high measurement accuracy and adaptability. The entire test device is easy to install and has a simple structure, which can meet the testing requirements of proportional valves of different specifications.

[0014] In order to solve the above technical problems, the present invention is solved through the following technical solutions: a proportional valve dynamic characteristics detection system, including a host computer, a proportional valve to be tested, and a metal cavity, the metal cavity has a penetrating flow channel, the flow channel inlet is connected to the proportional valve to be tested, the flow channel outlet is connected to a throttling orifice plate, the metal cavity has a pressure sensor matched with the flow channel, the pressure sensor electrical signal is connected to an oscilloscope, and the host computer electrical signal is connected to the proportional valve to be tested.

[0015] In the above technical solution, preferably, the metal cavity is a rectangular parallelepiped, and the flow channel is a cylindrical through hole penetrating the front and rear surfaces of the metal cavity.

[0016] In the above technical solution, preferably, a power amplifier is also electrically connected between the host computer and the proportional valve to be tested.

[0017] In the above technical solution, preferably, the throttling orifice plate is detachable on the flow channel outlet.

[0018] In the above technical solution, preferably, the flow channel diameter, flow channel length and flow area of ​​the throttling orifice are designed through the AMESim simulation model according to the natural frequency, cut-off frequency and flow area of ​​the proportional valve to be tested.

[0019] In the above technical solution, preferably, the maximum pressure to which the pressure sensor is subjected is changed by replacing a throttling orifice plate with a different flow area.

[0020] In the above technical solution, preferably, it also includes a power supply for supplying power to the host computer, the proportional valve to be tested, the pressure sensor and the oscilloscope.

[0021] Since the valve core opening of the proportional valve is directly related to the flow rate, the present invention designs a system to measure the dynamic characteristics of the proportional valve by measuring the pressure change of the rear end flow channel through a high-frequency response pressure sensor to indirectly respond to the flow rate. The entire system includes a host computer, a proportional valve to be tested, a metal chamber, a pressure sensor, an oscilloscope and a power supply.

[0022] Host computer: The host computer is connected to the proportional valve through a power amplifier, and is used to provide a step electrical signal or a sinusoidal electrical signal of a specific frequency to the proportional valve to drive the proportional valve to work.

[0023] Proportional valve to be tested: The proportional valve to be tested is connected to the test device of the system. By controlling the opening or closing of the proportional valve to be tested, dynamic detection of the valve core displacement during the test is achieved.

[0024] Metal chamber: The rear metal chamber is a rectangular parallelepiped. There is a cylindrical through hole on the front and back sides as a flow channel. The inlet of the flow channel is connected to the proportional valve to be tested, and the outlet is connected to the throttling orifice plate; the orifice plate is removable and replaceable, and connected by screws. There is a threaded hole on one side of the chamber for installing the pressure sensor. If necessary, there is a threaded hole on the other side for connecting the gas source.

[0025] Pressure sensor: Installed on the side of the metal cavity, used to detect the pressure changes in the cavity in real time. The measurement range of the sensor is determined through simulation analysis to ensure that its accuracy matches the system.

[0026] Oscilloscope: The oscilloscope is used to read the electrical signal output by the pressure sensor and convert it into the actual pressure value in the chamber. The oscilloscope can accurately monitor the time from the moment the electrical signal is turned on and off to the time when the pressure reaches 90% of the maximum value for the first time.

[0027] Power supply: Provide stable power supply for the host computer, pressure sensor and other system equipment to ensure the normal operation of the entire system.

[0028] In the dynamic characteristics test of proportional valves, the design of the rear end flow channel is crucial to the test results. Parameters such as the length, diameter and flow area of ​​the flow channel directly affect the pressure response characteristics of the system, thereby affecting the accuracy and upper limit of the dynamic characteristics test. Specifically: Influence of pipe length: Too short pipe length will cause rapid pressure fluctuation in the chamber, which may cause unstable measurement, especially in high-frequency testing, where the peak value of pressure change is difficult to capture, affecting the test accuracy of the system. Too long pipe length may cause delay in pressure fluctuation, increase test response time, and even cover up the real dynamic characteristics of the valve core, affecting the timeliness and accuracy of the test.

[0029] Influence of pipe diameter: Too small a pipe diameter will increase fluid resistance, reduce the flow rate of the system, and cause the pressure response in the chamber to be too slow, making it difficult to reflect the rapid action characteristics of the proportional valve. Too large a pipe diameter may make the pressure fluctuation in the chamber unclear, the system response becomes sluggish, and affect the test accuracy.

[0030] Orifice flow area: The orifice flow area directly affects the speed and amplitude of pressure change in the chamber. The larger the flow area, the faster the pressure changes, which is suitable for proportional valves with higher test frequency; the smaller the flow area, the more suitable for proportional valves with lower test frequency but higher stability. The difficulty in determining the orifice flow area lies in the need to comprehensively consider the dynamic characteristics of the system and the precise control of the throttling effect, which usually requires optimization through a combination of simulation and actual testing.

[0031] In the dynamic characteristics test of the proportional valve, the design of the rear-end flow channel is crucial to the test results. Parameters such as the length, diameter and flow area of ​​the flow channel directly affect the pressure response characteristics of the system, thereby affecting the accuracy and upper limit of the dynamic characteristics test. The determination of these parameters requires balancing the response speed and stability, which is a key challenge in the design of the dynamic characteristics test system. The difficulty in determining these key parameters lies in the need to ensure that the system structure is compact, stable and easy to install while meeting the dynamic test requirements. Traditional methods may face the problems of requiring multiple experimental adjustments, high costs and complex process requirements. The present invention effectively reduces the difficulty of parameter determination and improves the accuracy and efficiency of system design by using the AMESim simulation model to predict the parameter effects and combining it with actual measurement verification.

[0032] This application is a non-destructive test, which is suitable for various specifications. The dynamic characteristics of the proportional valve are detected by a pressure sensor and an oscilloscope. There is no need to directly measure the displacement of the valve core, which avoids damage to the proportional valve structure. The system has a compact structure and is easy to install. The test parameters are adjusted using a detachable throttling orifice plate, which can adapt to the test requirements of proportional valves of various specifications, thereby expanding the application range of the system. This application improves the measurement accuracy and response speed. The diameter and length of the rear metal cavity and the aperture of the throttling orifice plate are determined by simulation analysis, so that the system has excellent dynamic response characteristics, ensuring a rapid response to the dynamic changes of the proportional valve, and significantly improving the measurement accuracy and real-time performance of the system. Especially when measuring proportional valves with higher natural frequencies, their dynamic characteristics can be better captured. By optimizing the flow channel design of the rear cavity, the system can detect higher frequency response characteristics, which is significantly better than traditional measurement systems and expands the system's ability to capture high-speed dynamic changes. This application is low-cost and easy to operate. It takes into account the feasibility of cost and processing in design and manufacturing, and the overall test equipment cost is relatively low. Due to its compact structure and flexible adjustment mechanism, it is simple to operate and suitable for rapid deployment and testing.

[0033] Compared with the prior art, the combination of the pressure sensor and the oscilloscope in the system of the present application enables real-time and accurate detection of the dynamic response of the proportional valve. At the same time, simulation analysis helps determine the size of the rear-end chamber and the throttling orifice plate, ensuring that the system is compact and has high measurement accuracy and adaptability. The entire test device is easy to install and has a simple structure, which can meet the testing needs of proportional valves of different specifications. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the system of the present invention.

[0035] Figure 2 This is the AMESim model diagram of Example 1 of the present invention.

[0036] Figure 3 This is a diagram of the first simulation result of Example 1 of the present invention.

[0037] Figure 4 This is a diagram of the second simulation result of Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The following is a clear and complete description of the technical solutions of the various embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments described in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1: Figures 1 to 4As shown, a proportional valve dynamic characteristic detection system includes a host computer, a proportional valve to be tested, and a metal cavity, wherein the metal cavity has a flow channel running through it, the flow channel inlet is connected to the proportional valve to be tested, the flow channel outlet is connected to a throttling orifice plate, the metal cavity has a pressure sensor matched with the flow channel, the pressure sensor is electrically connected to an oscilloscope, and the host computer is electrically connected to the proportional valve to be tested. A power amplifier is also electrically connected between the host computer and the proportional valve to be tested. The metal cavity is a rectangular parallelepiped, and the flow channel is a cylindrical through hole running through the front and back surfaces of the metal cavity. The throttling orifice plate is detachable at the flow channel outlet. It also includes a power supply for the host computer, the proportional valve to be tested, the pressure sensor, and the oscilloscope.

[0040] When AMESim simulation model is used to design the flow channel diameter, flow channel length and orifice plate flow area, the simulation model is first established. Figure 2 :Build a proportional valve test system model in the simulation software AMESim according to the test system, including gas source, proportional valve, signal source, gas flow channel, pressure sensor, orifice plate. Set the initial conditions such as fluid type (such as dry air) and gas source pressure. Set the basic parameters of the proportional valve to be tested, such as flow area and natural frequency.

[0041] In this embodiment, the fluid is dry air, the air source pressure is 7 bar, the flow area of ​​the proportional valve to be tested is 5 square millimeters, and the natural frequency is 200 Hz.

[0042] Secondly, determine the key parameters to be optimized: clarify the key design parameters that need to be optimized, the diameter of the rear end flow channel, the length of the rear end flow channel, and the flow area of ​​the throttling orifice plate. Set an initial value for each parameter.

[0043] Set the test signal and design requirements again: Set the design goal of the system. Under a 101Hz sine wave signal, the air pressure detected by the pressure sensor should not be less than 70.7% of the 1Hz signal. Apply drive signals of different frequencies to the proportional valve, such as 1Hz, 51Hz, and 101Hz sine wave signals. The proportional valve to be tested is driven by sine wave signals of 1Hz, 51Hz, and 101Hz, respectively. Since the sine wave signal is much higher than the natural frequency of the proportional valve, the ideal system design should make the air pressure detected by the pressure sensor when the sine wave signal is 101Hz greater than 70.7% when the sine wave signal is 1Hz, that is, 101Hz is the cutoff frequency. In electronics, the cutoff frequency is the frequency at which the output signal power of a circuit (such as a wire, amplifier, or electronic filter) exceeds or falls below the conduction frequency. Usually, the output power at the cutoff frequency is half of the conduction frequency, which is equivalent to the power represented by the position of 3 dB lower on the Bode plot, because at this time the power ratio V1 / 2 ≈0.707 is the output power transmitted to the frequency band.

[0044] Then the initial parameter setting and simulation verification: run the simulation to obtain the system response results; evaluate the results to check whether the simulation results meet the design requirements. If not, record and analyze the reasons. When the pressure response in the cavity is slower than the signal driving the proportional valve, you should consider increasing the pipe diameter and shortening the pipe length; if the pressure peak measured by the pressure sensor is significantly attenuated when the signal frequency driving the proportional valve is significantly lower than the natural frequency of the proportional valve, you should consider reducing the pipe diameter and shortening the pipe length.

[0045] Then adjust the design parameters: Consider the feasibility of processing and manufacturing (leave enough space for the installation of proportional valves, pressure sensors, and orifice plates), and redesign and adjust the key parameters based on the previous simulation results. Run the simulation again for the modified and optimized parameters to obtain the results and verify whether they meet the expected design requirements. Repeat the above steps until the expected design requirements are met.

[0046] Finally, physical processing and testing are carried out: the actual test fixture and orifice plate are processed according to the final optimized parameters. The test system is built, and the proportional valve to be tested is experimentally verified. The experimental results are compared with the simulation results to verify the rationality of the simulation design results.

[0047] When the simulation design is that the flow channel diameter is 25mm, the flow channel length is 30mm, and the orifice plate flow area is 10 square millimeters, the simulation results are as follows Figure 3 As shown. Figure 3 As far as we know, the first simulation design does not meet the above design requirements. In order to take into account the feasibility of processing and manufacturing, the system parameters are redesigned: the flow channel diameter is 10mm, the flow channel length is 10mm, and the orifice plate flow area is 10 square millimeters. The simulation results are as follows: Figure 4 As shown. Figure 4 As far as we know, the theoretical upper limit of the proportional valve frequency response characteristic of the second simulation design of this system can reach about 150Hz. The test system is built according to this parameter, and the experimental results are basically consistent with the simulation results. When the diameter or model of the proportional valve to be tested changes, the maximum pressure at the pressure sensor can be changed by changing the flow area of ​​the orifice plate, so that a set of test systems can adapt to multiple types of proportional valves without changing the pressure sensor used.

Claims

1. A proportional valve dynamic characteristics detection system, characterized in that: It includes a host computer, a proportional valve to be tested, and a metal cavity. The metal cavity has a flow channel running through it. The inlet of the flow channel is connected to the proportional valve to be tested, and the outlet of the flow channel is connected to a throttling orifice plate. The metal cavity has a pressure sensor that matches the flow channel. The electrical signal of the pressure sensor is connected to an oscilloscope, and the electrical signal of the host computer is connected to the proportional valve to be tested.

2. A proportional valve dynamic characteristics detection system according to claim 1, characterized in that: The metal cavity is a rectangular parallelepiped, and the flow channel is a cylindrical through hole that passes through the front and rear surfaces of the metal cavity.

3. A proportional valve dynamic characteristic detection system according to claim 1, characterized in that: A power amplifier is also connected between the host computer and the proportional valve to be tested via electrical signals.

4. A proportional valve dynamic characteristics detection system according to claim 1, characterized in that: The throttling orifice plate is detachable on the flow channel outlet.

5. A proportional valve dynamic characteristic detection system according to claim 1, characterized in that: According to the natural frequency, cut-off frequency and flow area of ​​the proportional valve to be tested, the flow channel diameter, flow channel length and flow area of ​​the throttling orifice plate are designed through the AMESim simulation model.

6. A proportional valve dynamic characteristic detection system according to claim 4, characterized in that: The maximum pressure to which the pressure sensor is subjected can be changed by replacing throttling orifice plates with different flow areas.

7. A proportional valve dynamic characteristic detection system according to claim 1, characterized in that: It also includes a power supply for the host computer, the proportional valve to be tested, the pressure sensor and the oscilloscope.

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