Stabilization of centrifuges with instabilities due to fluid-structure interactions: various control approaches

摘要

Partially filled centrifuges exhibit unstable behavior over particular rotational speed ranges. To remove this unstable behavior, three different control approaches are presented which are experimentally implemented using a magnetic bearing. First, by means of a PD-controller the system stiffness is changed leading to a shift of the instability region. Second, the instability region is removed by a cross coupled feed back of the rotor vibration velocities. This cross coupling directly counteracts the fluid excitation mechanism. Third, a disturbance observer is presented which allows to estimate and compensate the not exactly known fluid force.