Harmonic Analyses with Measuring Electromagnetic Forces and Torques for Magnetically Levitated Planar Motors

Abstract

This paper focuses on analyzing the harmonics of electromagnetic forces and torques of a magnetically levitated planar motor by measuring these forces and torques. By a multi-dimension force/torque sensor measure system, all electromagnetic forces and torques of a planar motor are measured simultaneously. And then these measured data are processed and analyzed in terms of frequency orders, frequency spectrum amplitudes, and power spectral densities. Data analyses indicate the real electromagnetic forces/torques include different odd order harmonics which result from the Halbach magnetic field. The frequency spectrum amplitudes of harmonics attenuate with the increasing of the harmonic orders and the power spectral densities of harmonics diminish fast with the increasing of the harmonic orders. These harmonic analyses can be used to select control strategy and closed-loop bandwidth for the real-time control of the magnetically levitated planar motor.