Real-Time Control of Rotor Vibrations With Active Bump-Type Foil Bearings
Hanqing Guan, Kai Feng, Ke Yu, Dongling Sun, Yuanlong Cao
Abstract
The rotor supported by gas foil bearings (GFBs) suffers severe vibrations at extremely high rotating speed, which weakens the stability of the rotor-GFBs system. Although current solutions including increasing structural damping and mechanical preloads of GFBs suppress the rotor vibrations, they lead into larger wear during the lift-off process and higher friction torque during operation. In this article, active bump-type foil bearings with advantages of actively controlled mechanical preloads are utilized to rotor-GFBs system aiming at suppressing the rotor vibrations in real time. Open-loop control is utilized to obtain the proper U at different rotating speeds. The bifurcation diagrams of the rotordynamic responses under different voltages and rotating speeds are predicted to explain the relationship between U and real-time control of rotor vibrations theoretically. Proportional-integral-differential control method is utilized to control the vibrations of rigid rotor within relatively tight bounds under the conditions of constant rotating speed, coast-down process, and speed up and down process.