Vibration Compensation and Precision Tracking of a Rotating Shaft by Nonlinear State Feedback

In this paper, a nonlinear observer-based state feedback is derived to achieve precision tracking of a rotating shaft supported by active magnetic bearings (AMBs). Velocity and disturbance observers are constructed which operate in a hierarchical manner. This approach reduces the order of the design and modularizes compensation for synchronous vibration. Experimental results on a commercially available five degree-of-freedom system demonstrate accurate position tracking over the bearing air gap.