Predictive control based on fuzzy model: a case study

LEPETIC, MARCO; SKRJANK, IGOR; CHIACCHIARINI, H.G.; MATKO, DRAGO

Melbourne

Conferencia; Fuzzy Systems, 2001. The 10th IEEE International Conference on; 2001

IEEE

The implementation of the fuzzy predictive functional control (FPFC) on the magnetic suspension system is presented in the paper. The magnetic suspension system was in our case the pilot plant for magnetic bearing and is an open - loop unstable process, therefore a lead compensator was used to stabilize it. The high quality control requirements were a-periodical step response and zero steady-state error. Adding the integrator to a feedback causes overshoot. The solution to the problem was cascade control with fuzzy predictive functional controller in the outer loop. To cope with the unknown model parameters and the nonlinear nature of the magnetic system, a fuzzy identification based on FNARX model was used. After successful validation the obtained fuzzy model was used for controller design. The FPFC is compared with a cascade PID control. The results we obtained with the FPFC are very promising and hardly comparable with conventional control techniques.