Identification-compensation approach for unknown disturbances via the estimate model of numerical differentiation

Researching the characteristic of macroscopical motion, numerical differentiation is introduced to describe the dynamics of an unknown kinematic process, then the estimation model of numerical differentiation (NDEM) is constructed. Robust and simple models can be created by this approach for various applications, and it is easy to select suitable estimation algorithms to satisfy estimate quality. In the paper, NDEM is established for the guidance process of spacecraft rendezvous and docking (RVD) disturbed by unknown inputs, the kinematic parameters of RVD are captured for guiding outputs, and the unknown disturbances are estimated for active compensation. Simulation results show that NDEM is a robust model for obtaining accurate state estimation, and the precision of RVD guidance is immune from the unknown disturbances by the compensated control law.