Proportional servo valve is an important executive component in modern hydraulic control system, which has the characteristics of fast response, high control accuracy and good adjustment continuity, and is widely used in industrial automation, aerospace, construction machinery and other fields. Correctly adjusting the proportional servo valve is very important for the stability, accuracy and overall performance of the system. This paper will introduce the basic structure, working principle and adjustment method of proportional servo valve in detail.
First, the basic structure and working principle of proportional servo valve
The proportional servo valve is mainly composed of electromagnetic coil, slide valve, feedback mechanism and valve body. Its core principle is to control the magnetic force of the electromagnetic coil through the input electrical signal (usually voltage or current), and then push the slide valve to move and change the opening of the valve port, so as to control the flow and pressure of hydraulic oil and realize the accurate control of the actuator (such as hydraulic cylinder or hydraulic motor).
Compared with the traditional on-off valve, the proportional servo valve can realize continuous control, fast response and high control accuracy, and is suitable for closed-loop control system.
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Second, the main adjustment parameters of proportional servo valve
When adjusting the proportional servo valve, you usually need to pay attention to the following key parameters:
1. Gain Adjustment: determines the amplification ratio between the input signal and the output flow, and affects the response speed of the system.
2. Deadband Compensation: It is used to eliminate the insensitive area near the zero position of the valve core caused by friction or manufacturing error.
3. Dynamic response adjustment (such as damping adjustment): it affects the stability and dynamic characteristics of the system and prevents overshoot or vibration.
4. Pressure gain adjustment: used to adjust the sensitivity of the pressure control loop.
5. Null Adjustment of current: ensure that the valve is in the neutral position when the input signal is zero, so as to prevent drift.
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III. Adjustment Steps of Proportional Servo Valve
1. Preparation:
-Ensure that the hydraulic system is clean and the oil meets the requirements.
-Check the electrical connection and confirm that the control signal is stable.
-Turn off the system load or set it to the minimum load state.
2. Zero adjustment:
-When the input signal is 0V or 4mA, adjust the zero potentiometer to stop the actuator (such as hydraulic cylinder).
-This step is to eliminate the mechanical offset of the spool.
3. Dead zone adjustment:
-When the input signal is close to zero, observe whether the actuator has any action.
-Eliminate the unresponsive area by adjusting the dead-time compensation potentiometer to ensure the smooth start of the system.
4. Gain adjustment:
-Gradually increase the input signal and observe the speed and response of the actuator.
-Increasing the gain can improve the response speed, but too much will lead to oscillation or instability, which needs to be optimized according to the system characteristics.
5. Dynamic performance optimization:
-Introduce step signal to test system response.
-Adjust the damping or filtering parameters to make the system stable while responding quickly, and avoid overshoot or delay.
6. Closed-loop control parameter setting (PID adjustment):
-If the system is closed-loop, PID parameters should be adjusted according to the feedback signal to achieve higher control accuracy.
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Fourth, matters needing attention
-During the adjustment process, the parameters should be adjusted step by step to avoid one-time change.
-The change of system temperature may affect the performance of the valve, so it is recommended to adjust it under stable working conditions.
-After debugging, multiple tests should be conducted to ensure the system can run stably under different loads and working conditions.
-Using professional test equipment (such as oscilloscope, pressure sensor, etc.) can improve the adjustment efficiency and accuracy.
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V. Conclusion
As the core component of hydraulic control system, the regulating quality of proportional servo valve directly affects the performance of the whole system. By setting the parameters such as gain, dead zone and dynamic response reasonably, the actuator can be controlled with high precision. Mastering the correct adjustment method not only helps to improve work efficiency, but also prolongs the service life of equipment and improves the overall reliability of the system. For engineers and technicians, a deep understanding of the working principle and adjustment skills of proportional servo valve is an important foundation to ensure the stable and efficient operation of hydraulic system.