Decentralized nonlinear adaptive output-feedback controller based on high gain state and perturbation observer

his paper proposes a decentralized nonlinear adaptive output-feedback controller (DNAOFC) for a class of interconnected unknown nonlinear systems. The combined effect of unknown system dynamics and interactions between subsystems is defined as system perturbation and represented by a fictitious state. The system states and perturbation are estimated by a high gain state and perturbation observer (HGSPO) and then employed for realization of the DNAOFC. The performance of the proposed controller is demonstrated by controlling two interconnected inverted pendulums on carts using two locally installed DNAOFCs. The simulations results show the effectiveness of the decentralized controllers.