Delay-dependent output feedback integral sliding mode control of singularly perturbed systems

This paper presents a descriptor system method for output feedback integral sliding mode control of singularly perturbed systems. The fast state, representing the derivative of output, is approximated with aid of an artificial time-delay estimator. Then, a delay-dependent integral sliding mode controller is designed to ensure the occurrence of sliding phase since the initial time instant. The finite frequency uncertainty is divided into the matched and uncertainty uncertainty. On this basis, the proposed controller contains the nominal part to attain the robustness to the unmatched uncertainty, and the switching part to compensate the matched uncertainty. Finally, the effectiveness of the design method is verified in a mass-damper-spring system subject to finite frequency perturbations.