Robust control design for nonlinear Magnetic Levitation System using Quantitative Feedback Theory (QFT)

There is a growing demand for magnetic suspension systems, especially in the field of high accuracy multi-dimensional positioning. Magnetic levitation (Maglev) systems offer many advantages such as frictionless, low noise, the ability to operate in high vacuum environments and so on. Reliable and robust controller synthesis of this system is of great practical interest. Robustness is a key issue in designing a control system for a magnetic levitation as the models are never 100 percent accurate and the uncertainties in the model must be accounted. In the present work, a new approach using quantitative feedback theory (QFT) is presented for design of a robust two degree of freedom controller for magnetic levitation. Experimental tests are conducted to check the reliability and robustness of the designed control system by subjecting it to disturbances. The experimental test results show the control system design to be reliable and robust.