View article

This paper treats aspects concerning the design of two-degree-of-freedom (2-DOF) PI-fuzzy controllers dedicated to the position control of magnetic levitation system. 2-DOF Mamdani and Takagi-Sugeno PI-fuzzy controller structures based on the fuzzification of some linear blocks in the 2-DOF linear controller structures are discussed. A design approach of three new cascade control system structures is offered. The design approach carries out first the pole placement design of the inner state feedback control system. The 2-DOF PI-fuzzy controllers in the outer loops are next designed to merge separately designed linear PI controllers accounting for the linearization of the process model at certain operating points. Samples of real-time experimental results related to a laboratory equipment are given to validate the new fuzzy control system structures and the design approach.