# Load Prediction Control Study of a Pitch Control System for Large Offshore Wind Turbines
## 5 Conclusions  
In this paper, to meet the demand for the high-precision control of the pitch control system of offshore wind turbines under complex environmental loads, a nonlinear mapping model comparing hydraulic cylinder displacement and pitch angle is established, and an electromechanical-hydraulic coupled state-space equation containing the electromagnetic characteristics of the servomotor, the continuity of the flow in the hydraulic system, and the dynamics of the load is constructed. A load prediction method is proposed, and a position control strategy based on the compensation of the load disturbance is designed, with higher displacement tracking accuracy and stronger anti-interference ability than the traditional PID control, and its superiority is revealed through simulation and experimental verification.  
The load observation model proposed in the paper, grounded in physics-based equations, is theoretically scalable to turbines of varying sizes. However, under extreme operating conditions, factors such as variations in system leakage coefficients and hydraulic fluid viscosity may necessitate a reevaluation of key parameters within the model. The load disturbance compensation strategy proposed in this study provides an effective solution for high-precision anti-disturbance control of an offshore wind turbine pitch system, which can be applied not only to the offshore wind turbine pitch system, but also to the same type  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Instruction Signal** & **Parameter** & **PID Control** & **LDC Control** \\ \hline Step signal (800 mm) & Settling time & 18.2 s & 17.4 s \\ Continuous step signal (100–800 mm) & Average settling time & 4.97 s & 4.38 s \\ Sinusoidal signal (50 mm, 0.05–0.08 HZ) & Maximum tracking error & 12.66 mm & 2.42 mm \\ Displacement variance & 43.18 & 2.98 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Experimental performance comparison of LDC and PID control strategies.  
Figure 17: Sinusoidal experiment result.  
of strong-disturbance electro-hydraulic control system. However, the practical application still needs to overcome the challenges of the simplicity of the modeling assumptions, the reliability of the sensors, and the adaptability to extreme environments. Future work can explore the adaptability improvement of multiple types of turbines and further enhance the robustness of the system under extreme environments such as typhoons and extreme cold by integrating weather prediction, temperature adaptive algorithms, and digital twin technology. In addition, by combining edge computing and fault tolerance mechanisms, it is expected to realize autonomous and highly reliable operation under complex sea conditions, providing theoretical support for the intelligent development of renewable energy equipment.  
Conceptualization, X.W. and S.L.; methodology, S.L. and G.C.; experiment, J.C. and C.A.; software, X.W. and J.C.; investigation, X.K.; writing--original draft preparation, X.W.; writing--review and editing, J.C.; analysis, S.L.; project administration, C.A.; funding acquisition, C.A. and X.K. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the National Natural Science Foundation of China (U22A20178), the Basic Research Funds for the Universities of Xinjiang (XJEDU2024P087 and XJEDU2023P138), the Natural Science Foundation of the Xinjiang Uygur Autonomous Region (2022D01A244), the Guizhou Provincial Basic Research Program (Natural Science) ([2020]IZ054), and the Hebei Provincial Major Special Science and Technology Project (23281901Z).  
Not applicable.  
The original contributions presented in the study are included in the article; further inquiries can be directed to the corresponding author.  
Author [PERSON] was employed by the company Sichuan Chuanrun Intelligent Fluid Technology Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.