High-accuracy robust attitude stabilization of satellite with ultra-large flexible payload under rotational imbalance

Large-scale rotating payloads enable remote sensing satellites for wide-area observation missions, but rotational imbalance from the non-uniform mass distribution of the payloads will disturb the stability of satellite platform and observation accuracy. Thus, this paper develops a new robust finite-time composite controller to achieve the high-accuracy attitude stabilization of a satellite with a flexible payload with ultra-large rotational inertia and rotational imbalance. First, the coupling dynamics of the satellite platform and payload with static and dynamic imbalance are described, given parameter perturbations. Then, a finite-time disturbance observer is designed to accurately estimate triaxial imbalance torques, while system robustness to imbalance disturbances and multi-modal structural vibrations is enhanced by a finite-time homogeneous control law with input saturation. Modal responses are further efficiently attenuated through compensation. Finally, comparative simulation results demonstrate the significant superiority of the proposed controller. It notably enhances satellite attitude accuracy and stability with faster global convergence in typical rotating states of the payload. This paper offers an effective and practical solution to high-accuracy attitude stabilization of ultra-large satellites in future remote sensing.