Active electromagnetic levitation control of a flexible beam by using disturbance observer

This paper describes an active electromagnetic levitation control of a flexible beam using current and magnetic flux instead of a position sensor. An observer is used to estimate the position based on current, magnetic flux, fundamental, 1st and 3rd modes of vibration of the beam, and input voltage to the electromagnet. The controller combines state-feedback with the observer output to arrive at a new input voltage. Results obtained with a conventional observer and disturbance observer are discussed. Simulation and experimental results demonstrate the feasibility of the approaches.