Design of Nonlinear Controller for Magnetic Levitation System

Abstract

Magnetic Levitation Systems are used to levitate a ferromagnetic object in the air without any support. It has a wide area of applications because it eradicates energy losses that occur due to friction of the surface. In this thesis, nonlinear controllers have been designed by using backstepping, integral backstepping and synergetic control techniques that will help to obtain certain control objectives. Nonlinear controllers have been designed because of nonlinear dynamics present in the system model. The control objectives are used to generate a certain amount of magnetic flux by applying control input to the system. The magnetic flux is then used to levitate the body in air at a certain distance from the coil so that the movement of the body within that magnetic flux is negligible. The magnetic force provides an acceleration against the earth gravitational force to lift the body towards the coil. For each nonlinear controller, Lyapnouv based theory has been used to check the global asymptotic stability of the system. MATLAB/Simulink environment is then used to analyze the system performance for the proposed controllers. Moreover, a comparative analysis of proposed nonlinear controllers has been given with PI controller to study which controller is more efficient.