Decentralized Output-Feedback Controller for Uncertain Large-Scale Nonlinear Systems Using Higher-Order Switching Differentiator

A novel approximation-free differentiator-based output-feedback controller for uncertain large-scale systems (LSSs) is proposed. The considered LSS has nonautonomous and nonaffine-in-the-control subsystems which is yet to be tackled for decentralized output-feedback controller in the previous researches. The controller adopts a higher-order switching differentiator that can track the time-derivatives of a time-varying signal asymptotically. Through the differentiators, time-derivatives of output tracking errors are estimated and unstructured uncertainties in the controlled subsystems are compensated. The proposed decentralized output-feedback control formulae and the stability analysis are relatively simple in comparison to the previously proposed decentralized controllers. In this case, approximators such as fuzzy systems or neural networks are not required. The proposed controller guarantees that the tracking errors of the subsystems are asymptotically convergent to zeros and all the signals involved in the closed-loop systems are bounded.