Dynamics of Active Magnetic Bearings with Magnet Cores in Shape of a Cone

An approximately decoupling control system is designed for an active magnetic bearing system whose electromagnet cores are in the shape of a cone to have both functions of radial and thrust bearings. The bearing system is symmetric in structure: the rotor is symmetric and supported by two bearings composed of similar electromagnets at symmetrical positions with respect to the center of gravity. The magnet cores are made of solid steel. Experimental results are given for frequency responses of the rotor motion to a disturbance input and for transient responses to impact given to the rotor. The former is compared with the numerical results. The results show the usefulness of the design method of the control system.