Stable control of magnetically suspended motor with heavy self-weight and great moment of inertia

In this article, for the translation and radial rotation of the magnetically suspended motor (MSM) with heavy self-weight and great moment of inertia, robust control functions are designed to improve the disturbance attenuation by minimizing model uncertainties introduced by variations of current stiffness and displacement stiffness. On the one hand, the H_∞ control function with the mixed sensitivity is designed to the translational control of the MSM. On the other hand, for the rotation control of the MSM around radial axes, μ-synthesis is utilized to attenuate disturbances caused by the gyroscopic coupling with variable rotational speed. Simulation is developed to testify the disturbance attenuation of control functions when pulse-type, sinusoidal-type and random-type disturbances are imposed on the MSM respectively. Furthermore, experiments about axial translation and radial rotation are conducted to validate the robust stability of designed control functions. Both simulation and experimental results indicate that the robust control scheme has better ability on disturbance attenuation of the MSM with great inertia of moment and heavy self-weight.