Fuzzy PID Supervision for a Nonlinear, System: Design and Implementation

This paper presents an approach to design fuzzy supervisor for PID controllers used in the control of nonlinear systems. In the proposed approach, the design is based on an output performance criterion, namely a response with minimum settling time and without overshoot, whatever the operation conditions may be. The application used for a demonstration is a three-tank-system where the connection between the tanks and the leakage in each tank are simultaneously taken into account (MIMO system). According to the proposed approach, two fuzzy PI supervisors are designed in order to modify on-line the parameters of two PI controllers. The implementation of this type of control in the simulator of the three-tank-system model and in the laboratory installation using rapid protyping, confirms through the results that the output performances are reached whatever the set points, the configuration and the initial water levels in the three tanks may be.