Adaptive forced balancing for multivariable systems

Abstract

A problem common to all mechanical systems with rotating shafts, including active magnetic bearing (AMB) systems, is the synchronous vibration caused by mass unbalance. Autobalancing compensation causes AMB actuators to spin a rotor about its inertial axis and thus eliminate the centrifugal forces due to mass unbalance. However, because mass unbalance is modelled as a sinusoidal sensor disturbance occurring below loop bandwidth frequency, no available compensation method reduces vibration yet preserves the desired loop frequency response. Adaptive forced balancing (AFB) solves this problem and has been applied to single-end, AMB suspensions - the SISO case. This paper extends AFB compensation to the MIMO case. Simulations of a double-end, AMB suspension verify the success of our method.