Design of intelligent stabilizing controller and payload estimator for the electromagnetic levitation system: DOBFLC approach

This article presents the design of an intelligent stabilizing controller and payload estimator using the Disturbance Observer Based Fuzzy Logic Controller (DOBFLC) approach in the region of the Electromagnetic Levitation System (EMLS). EMLS is one of the unstable and nonlinear benchmark systems with a wide range of applications. Investigation reveals that the payload is one of the prime sources of the vertical disturbance for the EMLS. Initially, the stabilizing controller has been designed using the Pre-filter based Fuzzy-PID controller based on the ITAE criterion in the absence of payload. Next, the payload estimator has been developed in the presence of the vertical disturbance due to payload for sinusoidal and variable step-change patterns. Finally, the disturbance corrector is hybridized with the primary FLC to achieve the stabilizing control as well as the disturbance rejection control using the proposed methodology. Simulation results are presented to validate the efficacy of the proposed design under the payload variation of 0–20% similar to the medium speed MAGLEV trains. Also to confirm the superiority of the proposed approach, the results obtained by the DOBFLC approach are compared with the DOBC plus LQR approach for the fixed as well as variable step change of set points and payload.