MIMO Fuzzy Logic Control of a Liquid Level Process

A large number of design strategies exist for multivariable control situations. Many of the methods require a linear time-invariant process characterisation in the form of a state space model or transfer function matrix description. Quite often this is not available and could be expensive to realise. If this latter route is pursued there needs to be considerable benefits in the quality of the resulting closed-loop performance. One alternative is to use the ‘expert’ approach of fuzzy logic where the plant is not modelled but the expert operator is. Application of such a controller is not so straightforward as many parameters need to be ‘tuned’ in order to provide precise control of a non-linear system.