Hybrid Control for High-Accuracy Inclination-Azimuth Regulation of Directional Drilling Attitude

Precise orientation control of drilling tools is fundamental to directional drilling trajectory management. This study establishes a hybrid control framework for the high-accuracy regulation of inclination and azimuth. First, we derived a kinematic model characterizing the dynamic evolution of inclination and azimuth, explicitly addressing their coupled dynamics and azimuthal time-delay effects. A comprehensive downhole motion model was developed to capture system behavior. Distinct control strategies were formulated for the inclination and azimuth subsystems and integrated into a unified hybrid architecture. Stability analysis decomposes the system into individual control loops, with inclination stability ensured through conventional criteria, while azimuth stability is transformed into a solvable linear matrix inequality problem. Experimental validation demonstrates the superior robustness and engineering applicability of the method, achieving minimal attitude deviation under perturbed conditions. This control design provides a theoretically rigorous solution that bridges advanced control theory with practical well construction requirements.