Design of PI Approximated 2 Degree of Freedom Control for Electromagnetic Levitation Application

In this paper, a digital controller is applied to distance control of the Magnetic Levitation System (MLS). The characteristics of the magnetic levitation are very nonlinear. This is a prime reason for the difficulty of controlling the magnetic levitation. Conventional control is normally not appropriate for this kind of application. Hence, a robust digital controller of the magnetic levitation using a combination of Proportional-Integral (PI) and Approximated 2 Degree of Freedom (A2DOF) controller method for keeping the level of magnetic ball with sudden change of setpoint is proposed. The simulation using MATLAB/Simulink and experimental results are shown. It demonstrates that the proposed digital controller of which gain parameters are determined by the proposed method satisfies the given specifications.