Fractional-Order Power Function Sliding Mode Control for Multi-Spacecraft Attitude under Switching Topology

To address the cooperative attitude tracking problem of multi-spacecraft under switching topology considering communication link failures, external disturbances, and model uncertainties, this paper proposes a fractional-order power function sliding mode control method. Firstly, a non-linear observer is designed to estimate disturbances in the formation attitude error model. Secondly, an absolute-value fractional-order power function is introduced to optimize the sliding surface, reducing chattering during topological switches while designing a fractional-order power function sliding mode controller, with global stability verified via the common Lyapunov method. Finally, switching topology scenario simulations demonstrate that compared with existing approaches, the proposed controller achieves a 40% reduction in chattering peak amplitude, a 50% improvement in global convergence speed, and a 50% reduction in stabilization energy consumption, validating its effectiveness.