A Suppression Method of Conical Motion of an Axi-Symmetrical Spinning Rigid Rotor Suspended by Magnetic Bearings

New definitions of nutation and precession are proposed. which are usuful not only for physical understanding but also for intuitive interpretation of the optimal control of axi-symmetrical spinning rigid bodies. At first it is shown that the spin axis does coning motion about the instantaneous angular momentum vector with constant rotational speed (nutation angular velocity) regardless of its coning angle. Next, steady state coning mot ions, which have been called as steady state precessional motion, are discussed based on angular momentum vector and it is shown that they have two modes; precessional mode and nutational one. Last [y. based on angular momentum vector, a method of control for conical motion of a spinning rigid rotor supported by a magnetic bearing system is derived and it has the same control structure as the optimal control which has been derived as a regulator problem by referenced paper.