Optimal control of a rotor partially filled with an inviscid incompressible fluid

Optimal control theory is used to stabilize a rotating cylinder partially filled with an inviscid, incompressible fluid. As an example, the theory is used to control a rotor consisting of two discrete masses connected by a flexible shaft. The fluid is inside one of the masses and the control force is applied to the other. The rotor-fluid system which is unstable without controls is shown to be stable when acted upon by a feedback force designed to minimize a suitable performance index.