Fixed time three-axis synchronous attitude controller design for agile satellite

Aiming at the problem of high-precision fixed-time three-axis synchronous attitude control of agile satellite with disturbance and uncertainty, a robust attitude control method based on fixed-time-synchronized theory is proposed. This method can ensure that the three-axis desired attitude of agile satellite converges uniformly and synchronously in fixed time, and the linear character of the attitude convergence trajectory can avoid attitude jitter and reduce unnecessary control consumption. At the same time, the maximum stabilization time is unaffected by the initial value, so it has stronger adaptability. In addition, a finite-time disturbance observer is designed to compensate the disturbance and uncertainty existing in the attitude control system. The mathematical simulation is conducted on the proposed method. It can be proved that the proposed method improves the robustness of the system, and the stability of the closed-loop system is proved based on Lyapunov stability theory.