Vibration Control of a Rotor-Magnetic Bearing System on the Moving Base Through H_∞ Control

Rotor-Active magnetic bearing (AMB) systems installed in an aircraft are supported by a moving base. An optimal controller is required to ensure the stability and ideal vibration response of the rotor-AMB system. In this paper, a rigid rotor-AMB system on an aircraft is modeled by the Lagrange principle. The moving base generates additional stiffness, damping and external forcing terms. H_∞ control method is applied to design a controller and compare it with a decentralized PID controller. The flight maneuvers of the dive-pull up and horizontal turn are mainly studied. The results show that when the aircraft is in different flight maneuvers, the H_∞ controller has a strong ability to resist base movement disturbance, and the rotor displacement of the H_∞ controller is smaller than that of the PID controller. As the flight speed V_a and maximum roll angle γ_m increase, the maximum rotor displacement of the H_∞ controller remains almost unchanged, but the peak control current of the AMB also increases and may even exceed the maximum allowable value. Therefore, the effect of base movement disturbance should be fully considered during the design process of the AMB.