Time-optimal control of n-tank system

In this study a generalised model of n-tank system was developes taking into account nonlinearities introduced by shapes of the tanks. Time-optimal level control problem was formulated and basic properties of the solution were analysed. It was found that under specified assumption the control is of "bang-bang" type and the number of switches is limited. Although the theoretical framework exists for deriving optimal controllers, it is virtually impossible to obtain the equations of switching subspaces in a closed form. In order to implement the controller, two different suboptimal control strategies were proposed and evaluated using a laboratory installation.