Observer-based practically prescribed-time stabilisation of fully actuated systems with mismatched disturbances

In the paper, we investigate the mismatched disturbances rejection problem and the practically prescribed-time control problem for high-order nonlinear systems. By using filter outputs, a series of observers are designed to compensate for the mismatched non-vanishing disturbances. Inspired by the high-order fully actuated system approach, the practically prescribed-time control scheme is presented based on the disturbances estimations. In contrast to the existing results, a distinctive advantage of the proposed control method is that the observer has a higher estimation accuracy in the case of the smooth control input. Finally, a simulation is conducted to demonstrate the performance of the presented control scheme.