Robust Nonlinear Control of a Three-Tank System in the Presence of Mismatched Uncertainties

In this paper, we propose a finite-time disturbance observer-based robust control method for output tracking of the Inteco three-tank system in the presence of mismatched uncertainties. The controller is designed in a backstepping manner. At each step of the virtual controller design, a robust feedback controller with some effective nonlinear damping terms is designed so that the system states remain in the feasible domain. The virtual controller is enhanced by a finite-time disturbance observer, and the dynamic surface control technique is adopted for the virtual controller to avoid the shortcoming of "explosion of terms". Theoretical analysis is performed and simulation studies on the Inteco three-tank system model are included. (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.