Finite-time active disturbance rejection attitude tracking control for rendezvous and docking simulator

For attitude tracking control of the spacecraft rendezvous and docking simulator, this paper designs two finite- time active disturbance rejection controllers by using an improved fast nonsingular terminal sliding mode surface and an improved adaptive law under the condition of external disturbances and inertia uncertainties existing. The proposed controllers of the improved adaptive control architecture are continuous, which can inhibit the disturbance effectively, meanwhile, the second controller can resolve the problem of the boundary layer theory that finite-time stability is lost within the boundary layer. The Lyapunov theory and simulation results show that the two proposed controllers can guarantee the finite-time stability of the system, and the system can converge to the equilibrium point quickly.