Active magnetic bearing-based tuned controller to suppress lateral vibrations of a nonlinear Jeffcott rotor system

Active magnetic bearing system is an up-to-date technology that supports rotors without physical contacts and facilitates the vibration control in rotating machinery. Within this research, a tuned positive position feedback controller is proposed to control the lateral vibrations in a Jeffcott rotor system having cubic and quadratic nonlinearities. The controller is integrated into the system via four electromagnetic poles that act as actuators. The nonlinearity due to the electromagnetic coupling is included in the system model. A second-order approximate solution to the system governing equations is sought by utilizing asymptotic analyses. Bifurcation behaviours are investigated for both the system and controller parameters. The influence of the air-gap size, bias current, disc eccentricity, feedback gain, and control gain on the vibration amplitudes has been explored. The analytical results approved that the proposed controller can reduce the vibration amplitudes close to zero at any spinning speed even at large disc eccentricity. Then, numerical confirmations for the acquired analytical results have been performed that illustrated an excellent agreement with the analytical ones. Finally, a comparison with already published articles is included.