Real time implementation of robust QFT controller and prefilter for magnetic levitation system

Controller design for magnetic levitation systems is considered to be difficult due to uncertainties and nonlinearities which existed in the system. The plant has inherently strong nonlinearities due to the natural properties of magnetic fields. Also the external disturbances will deteriorate the dynamic performance of the magnetic levitation system, and may give rise to system instability. These problem triggers enormous interests in designing various controllers for the non-linear dynamic system. Designing and implementing controllers for such systems is a meticulous work. In this paper, the robust QFT controllers and prefilters are designed using Interval Constraint Satisfaction Problem based method. The robust controller is designed by solving quadratic inequalities of robust stability and performance specifications. In QFT, the prefilter is designed to achieve the desired tracking specifications. The prefilter is designed by solving the quadratic inequalities of upper and lower tracking specifications. In this paper, the designed QFT controllers and prefilters are tested on the experimental setup designed by Educational Control Product Magnetic Levitation Setup ECP 730.