Disturbance Decoupling of Coupled Tanks: From Theory to Practice *

Mathematical technicalities, which are involved in the modern theory of non-linear control systems, many times prevents a wider use of the impressive theoretical results in practice. Attempts to overlap this gap between theory and practice are usually more than welcome and form the main scope of our interest in this work. An important control problem given by the disturbance decoupling is studied for a real laboratory model of coupled tanks. It is shown that the theoretical solution to the disturbance decoupling problem does not satisfy practical control requirememts. Accordingly, the solution is modified and yields a nonlinear controller with the distrubance decoupling. Experiments on the real plant, verifying and comparing the results with and without the disturbance decoupling, are included as well. It is shown that the disturbances practically do not affect the system output.