A unified approach for identification and control of electro-magnetic levitation system in delta domain

Abstract

This paper proposes a unified approach for identification and control of delta operator parameterized Electro-magnetic Levitation System (EMLS). Dynamic systems modelling with delta operator provide a unified framework in rapprochement between discrete-time dynamic models and its analog counterpart at fast sampling. Capitalizing this unique feature, the concept of time moment is recasted in delta operator formulation as delta time moment (DTM). These DTMs are then estimated from the input-output measurements taken from unknown plant to develop control law in an approximate model matching framework so that the compensated plant output follow a reference model output under an input excitation. The reference model is so parameterized in the complex delta domain that it embodies classical time, frequency and complex domain specifications and guarantee both stability and performance. Four different adaptive control law, i) Inverse control using DTM (ICDTM), ii) Pade Adapted Inverse control using DTM with error feedback (PICDTMEF), iii) Plant Delta Time Moment control scheme (PDTMC) and iv) Pade adapted Delta Time Moment control with error feedback (PDTMCEF) have been proposed to design control schemes for the EMLS. Simulation results show the effectiveness of the proposed methods.