Servo valve is an important control element in hydraulic system, which is widely used in industrial automation, aerospace, construction machinery and other fields. Its performance directly affects the control accuracy and response speed of the system. Among them, the sensitivity of servo valve is a key parameter, which reflects the response ability of servo valve to the change of input signal. This paper will introduce the definition, testing principle and testing method of servo valve sensitivity in detail.
First, the definition of servo valve sensitivity
The sensitivity of servo valve usually refers to its response to the change of output flow or pressure caused by the change of input electrical signal or mechanical signal. Specifically, it is the ratio of the output variation to the minimum input signal increment that causes the variation. High sensitivity means that the servo valve can respond quickly when the input signal changes slightly, thus achieving more accurate control.
Second, the significance of testing the sensitivity of servo valve
The low sensitivity of servo valve will lead to the slow response of the system, the decrease of control accuracy, and even affect the stability of the whole hydraulic system. Therefore, by testing the sensitivity of the servo valve, its working performance can be evaluated to ensure that it meets the requirements of system control in practical application. In addition, the sensitivity test is also
one of the important items for the ex-factory inspection and regular maintenance of servo valves.
Third, the basic method of servo valve sensitivity test
The sensitivity test of servo valve is usually carried out on the standard test bench, which mainly includes the following steps:
1. Prepare test equipment
The test equipment includes servo valve test bench, precision pressure sensor, flowmeter, signal generator and data acquisition system. The test bench should have a constant pressure oil supply system and a load adjustment function.
2. Set the test conditions
Before the test, it is necessary to set standard working conditions, including oil supply pressure, oil temperature, ambient temperature and load pressure, to ensure the accuracy and repeatability of the test results.
3. Apply the
input signal
Use a signal generator to input a gradually changing electrical signal (such as current or voltage) to the servo valve, and record the corresponding output flow or pressure change.
4. Measure the output response
The output change of servo valve is measured by high-precision flowmeter and pressure sensor. Record the minimum recognizable change value of output when the input signal changes slightly.
5. Calculation sensitivity
Sensitivity is usually expressed by the ratio of output variation to input signal variation. For example, if the output flow changes ΔQ when the input signal changes ΔI, the sensitivity s =Δq/Δ i..
Four, factors affecting the sensitivity of servo valve
-Clearance and sealing of valve core: Excessive clearance or poor sealing between valve core and valve sleeve will slow down the response speed.
-Stability of oil
supply pressure: fluctuating oil supply pressure will affect the accuracy of output flow.
-Control signal accuracy: The noise or drift of weak signal will affect the measurement result of sensitivity.
-Cleanliness of oil: Contaminants may cause the spool to stick and affect the response sensitivity.
V. Conclusion
To sum up, the sensitivity test of servo valve is an important means to ensure its performance stability and system control accuracy. Through scientific test flow and accurate measuring equipment, the sensitive characteristics of servo valve can be accurately evaluated, which provides a basis for subsequent maintenance adjustment and system optimization. With the continuous development of hydraulic control technology, the sensitivity testing technology of servo valve will also be improved, which provides strong support for realizing high-precision and high-speed automatic control system.