抄録
A design method of a dynamic compensator for magnetic bearings levitating a spinning rigid rotor is proposed. The control strategy is to move the angular momentum vector to the spinning axis for nutation (short period mode) suppression and to move the vector to the central position of the stator for precession (long period mode) suppression. It is necessary to estimate the angular momentum vector. A simple estimation method is proposed here without using observer system or rate signals of attitude angles. Low pass filters are used to obtain low frequency compoments, which nearly equal the angular momentum vector, from the observed attitude signals. It is shown that phase lag effects of the filter can be compensated by cross-feedback, whose physical meaning is clarified by a block diagram of the total system including the dynamic compensator. Stability is discussed using root locus method. Several numerical simulation examples are given, showing effectiveness of the method.
