Simulation Control of Three-Tank-System Using 2DOF Controller

The paper proposes an implementation of a 2DOF controller based on polynomial methods for control of a system of three serially connected tanks. A state-space model of the three-tank-system was figured out according to physical laws. Then an appropriate linear input-output model was computed from the state-space model. This model is related to the prime model, although it has a different structure. It can therefore be assumed that it describes the main properties of the controlled system in the same way as the prime model. The input-output model was then applied for design of the 2DOF controller. The system of three interconnected tanks has a nonlinear character and uncertain parameters. A description of its dynamical properties with the use of a linear model is appropriate just in a vicinity of a certain working point. The controller was then realized in an adaptive version with a recursive identification of an input-output model appropriate to the state-space model which was realized in Simulink environment and used for verification of the controller by simulation. Simulation results are also included in the paper.