Vibration Control using Fractional Derivative Feedback

(10th Report: Fractional-Order Servo LQR Control Experiments for a Magnetic Levitation System)

Abstract

Voltage-controlled suspension-type magnetic levitation systems are unstable systems in which, under uncontrolled conditions, the levitated object is either attracted to the electromagnet or falls. In addition, the electromagnetic force and the electrical characteristics of the circuit have strong nonlinearities. In this study, a magnetic levitation system is stabilized and controlled by fractional-order LQR control, which is a combination of LQR control and fractional calculus, in an actual experiment. In addition, for the case where a levitated object is controlled to a target position that deviates from the equilibrium point, a fractional-order servo LQR control method is developed. It is experimentally confirmed that the fractional-order LQR control has higher control performance than the conventional integer-order LQR control.