Proposal of Sliding Mode Controller based on Backstepping Technique for Control of Magnetic Levitation System

Magnetic Levitation System (MLS) is a nonlinear system and it is used extensively in many areas. The system's goal is to use the non-contact principle to magnetize the coil and cause the objects to float to a specific height. The magnetic force and the current flowing through the coil have a nonlinear relationship. In this paper first design of the back stepping controller is done to attain the wanted floating in presence of system related uncertainties and system behavior is witnessed. Then a Sliding Mode Controller (SMC) based on back stepping procedure is formulated. The control gains in this controller are designed in such a way that the characteristics polynomial whose coefficients are control gains is strictly Hurwitz and the closed loop system's asymptotic stability is assured. Simulations are performed and the magnetic ball tracking is observed considering step signal as reference in presence of disturbances. More accuracy is observed in terms of following the reference by the magnetic ball when it is used Sliding Mode Controller based on Back stepping technique instead of back stepping controller by considering pulse type disturbance. By simulation and analyzing results it is confirmed that the proposed control strategy is more effective.