## 3 Dynamic Prediction of Servo Valve Performance Degradation
### Preliminary Analysis of Data  
Pressure gain is an important concept that is often used to describe the responsiveness of a particular system under different operating conditions. In some cases, pressure gain can vary with time and therefore needs to be monitored and analyzed. This article provides details on the variation of pressure gain with time under different operating conditions. Firstly, we needed to understand the definition and meaning of pressure gain. Pressure gain is the rate of change of pressure at the output of a system for a given input signal. In some cases, the pressure gain of a system may change over time due to different operating conditions. This means that the system may have different response capabilities at different points in time. It is therefore important to understand the pattern of pressure gain over time under different operating conditions to optimize the performance and stability of the system. In practical applications, it is important to monitor the trend of pressure gain under different operating conditions. By monitoring and analyzing the pressure gain, we can better understand the performance and stability of the system and make adjustments and optimizations accordingly. For example, in some cases, we may need to increase the responsiveness of the system to accommodate changes in external loads. In this case, we can increase the pressure gain by adjusting the system parameters to increase system responsiveness. In summary, the pattern of pressure gain over time under different operating conditions has an important impact on the performance and stability of the system. Understanding these patterns and monitoring and analyzing them accordingly can help us optimize the system's performance and stability and thus better suit the application's requirements. The variation of pressure gain with time for different operating conditions is shown in Figure 4 below:  
As shown in Figure 4, we can see the trend of pressure gain over time for different operating conditions. As can be seen from the graph, the trend of pressure gain changed differently under other operating conditions. For example, the pressure gain for condition 1 showed a clear upward trend in the entire cycle, while the pressure gain for condition 10 did not show a clear upward trend. This indicates that the servo valve aged faster in condition 1 and slower in condition 2 during this period. The reasons for these trends may have been due to dynamic changes within the system caused by different operating conditions, such as oil contamination, differential pressure, or openness; changes in external loads; or changes in other factors. In addition, because servo valves are a commonly used control element, they are widely used in hydraulic systems. During use, leaks may occur inside the servo valve, resulting in reduced performance and increased system energy consumption. Therefore, it is important to monitor and analyze the variation pattern of the internal leakage of servo valves under different operating conditions over time. In this paper, we introduced in detail the internal leakage of servo valves under different working conditions with time. The internal leakage of a servo valve is the amount of leakage between the spool and the valve seat, which is usually used to describe the sealing performance of a servo valve. The internal servo valve leakage amount may change over time under different operating conditions. This may be due to factors such as wear of the servo valve's internal oil seal, the material's aging, etc. Therefore, it is important to understand how the internal leakage of servo valves varies with time under different working conditions to ensure the performance and stability of the system. As shown in the figure below, we can see the trend of the internal leakage of the servo valve under different working conditions with time. From the graph, we can see that the trend of the internal leakage of the servo valve was different under different working conditions.