Advanced target tracking in spacecraft attitude control systems using disturbance observer-based intelligent terminal sliding mode controllers

Spacecraft control is critical for mission success, especially when facing both unpredictable external disturbances, including gravity torques, solar radiation, and aerodynamic drag, and internal challenges such as uncertain inertia and actuator faults. In this study, a dynamic spacecraft attitude control is presented that incorporates both kinematic and dynamic aspects. To handle real-world complexities, a fast terminal sliding mode backstepping integral adaptive controller with fuzzy logic and super-twisting disturbance observer is proposed. Additionally, the proposed adaptive mechanism estimates and compensates for disturbances and variations in the control loop. The system employs a quaternion-based error formulation to effectively respond to angular deviations while avoiding singularities. The finite-time sliding mode controller guarantees rapid attitude error correction, even under bounded external disturbances. Furthermore, an adaptive compensation mechanism continuously estimates and mitigates system variations. Simulation results demonstrate the proposed method performs with high precision and reliability, which leads to a significant advancement in attitude control techniques for complex and demanding space missions.