Experimental Design and Verification of Extended State Observers for Magnetic Levitation System Based on PSO

This work presents analysis, design and implementation of two schemes of Extended State Observer (ESO) to estimate the position, velocity and unmeasurable states for magnetic levitation systems, Linear ESO (LESO) and Nonlinear ESO (NESO). The multiplicity of design parameters for both LESO and NESO made it difficult to find appropriate setting of these parameters such that to reach satisfactory performance of observation process. Particle Swarm Optimization (PSO) technique is used to improve performance of observation process by finding optimal tuned parameters of observer design parameter subjected to specified performance index. Theoretical results of both observers are firstly implemented in the environment of MATLAB/SIMULINK. Then, experimental state estimation of observers is set up based on feedback instrument (33-942S) to verify the simulated results. Root Mean Square (RMS) of estimation error has been used as an indicator to assess the performance of observers. The simulated and practical results showed that LESO could give better estimation performance than NESO.