Strength Quantification Composite Control for Flexible Satellites With Prescribed Performance

Attitude control performance under multiple disturbances is essential for flexible satellites to accomplish various missions, while the magnitude and rate of control signals (control strength) are also crucial for ensuring a long-term operation. In this article, a strength quantification composite control (SQCC) scheme, consisting of an extended refined disturbance observer (ERDO) and a prescribed performance controller (PPC), is proposed to meet the requirements of control performance and strength. First, a deep-coupled system model is constructed for satellites encompassing flexible dynamics and external disturbances. Then, based on an introduced exogenous disturbance system, the ERDO is proposed, utilizing partially known dynamics (e.g., vibration and polynomial) and parameters (e.g., damping ratios and frequencies), enabling accurate estimation of both flexible vibrations and external disturbances. Combining the ERDO and PPC, the SQCC scheme can achieve prescribed control performance and prequantified control strength simultaneously. Finally, numerical simulations and experimental studies demonstrate the efficacy of the proposed method.