Constrained discrete-time nonlinear controller for a fluid tank system

This paper basically follows [1], where the transfer function formalism in nonlinear control systems, both continuous and discrete-time, is discussed. Here, we demonstrate how such a formalism can be adopted to design constrained nonlinear discrete-time controller for a fluid tank system. The first step consists in finding appropriate nonlinear discrete-time description for a fluid tank system, which is, in general, a difficult task, as it involves solving nonlinear differential equations. Second, we design nonlinear discrete-time controllers which linearize closed loop, eliminate input disturbance and deal with the controller output constraint. Finally, all results are verified on a real fluid tank system.