Influence of Magnetic Unbalance Pull Force on Rotor Trajectory Control in Oscillatory Motion Mechanism Using a Bearingless Motor

In machines with oscillatory motion mechanism, it is concerned that mechanical bearings and cams are subjected to heavy loads, and lead to their wear and tear. To solve these problems, the authors have proposed a built-in motor with oscillating movement function by applying bearingless drive technique. By moving the levitated rotor to any radial direction in the airgap and controlling the rotor position, the oscillatory motion is successfully performed. The range of application of the proposed oscillatory motion mechanism with the bearingless motor (BelM) will be considerably expanded if the region of the rotor trajectory will be more expanded. However, it is concerned whether the oscillatory motion will be able to be performed due to larger magnetic unbalance pull force. In this paper, the influence of magnetic unbalance pull force on the rotor trajectory control is discussed based on the simulation results using MATLAB/Simulink. It is proved that the trajectory control is correctly performed.