Distributed Nonlinear Disturbance Observer-Based Refined Cooperative Control for Multi-Satellite with Mandatory Pointing Constraint

Achieving consensus control is essential for highprecision satellite formation and the rapid deployment of laser communications within very low earth orbit (VLEO) constellations. However, formation flying missions pose strict pointing constraints on VLEO satellites. Furthermore, the satellite bodies are subjected to multi-source disturbances, such as flexible vibrations and environmental disturbances, degrading the attitude control accuracy, which in turn affects the relative attitude acquisition. To address the anti-disturbance high-precision consensus problem, this paper proposes a cooperative prescribed performance control scheme by integrating a distributed nonlinear disturbance observer (DNDO) and a distributed relative attitude observer (DRAO). Firstly, considering the actual satellite communication topology, a DRAO is designed to enable each satellite to acquire its desired pointing direction. Secondly, a DNDO is developed based on the disturbance dynamics of each satellite to achieve precise estimation of disturbances. Finally, by combining the DNDO and DRAO, a prescribed performance control scheme is designed based on barrier Lyapunov function under pointing angle error constraints. Simulation results based on a multi-satellite system consisting of five satellites demonstrate the effectiveness and superior performance of the proposed method.