Observer Design of Lipschitz Output Nonlinearity with Application to Asymptotic Rejection of General Periodic Disturbances

Abstract

AbstractIn this paper, observer design for systems with nonlinear outputs is investigated, and a sufficient condition is provided for the convergence of the estimates. The proposed observer design is then applied to estimate general periodic disturbances which can be modelled as nonlinear outputs of harmonic oscillators. The proposed observers for general periodic disturbances are then exploited for internal model design for asymptotic rejection of nonlinear systems with ISS zero dynamics. A number of problems on disturbance rejection and output regulation can be formulated in a disturbance rejection form shown in the paper to which the proposed nonlinear Lipschitz internal model can be applied. An example is included to demonstrate the proposed design strategies.