Discussion on Adaptive Estimation Approach for Bounded Disturbances with Simple Structure*

This paper discusses a novel adaptive disturbance observer (ADO) for systems subjected to bounded disturbances. The gains with adaptation are given, and the estimate error of the disturbance is guaranteed to be ultimately stable. The proposed ADO is capable of achieving a better dynamic per-formance compared with the standard linear DO. As a trade-off, it outperforms other DOs and reduces the control burden simultaneously. Moreover, the ADO has a simpler structure than the nonlinear DO because of its linear representation. Simulation results verifies the effectiveness and superiority of the proposed approach, and application to the attitude tracking for the hypersonic reentry vehicle (HRV) is also presented.