Observer Based Sliding Mode Control: Equivalence with Classical Frequency Domain Control

In this article, we find an "on the average" equivalence between observer-based Sliding Mode control and classical output feedback compensation networks. The average output feedback control actions are found to be naturally implemented via a one-dimensional Delta-Sigma modulator circuit absorbing the underlying sliding regime defined in the state space. We focus on perturbed pure-integration switched systems, representing a paradigm of the input-output representation of an on-off controlled flat system. The simplified model is assumed to undergo endogenous (state-dependent) and exogenous disturbances in the form of a, lumped, total disturbance input. Experimental results are presented for the output trajectory tracking task on a single link manipulator-DC motor combination.