Rotor vibration with auxiliary bearing contact in magnetic bearing systems Part 2: Robust synchronous control for rotor position recovery

Abstract

A number of conditions or events may produce rotor motion that involves contact with auxiliary bearings. Standard adaptive and closed-loop control strategies based on linear dynamics can cause instability when contact occurs, resulting in increased contact forces and vibration compared with the uncontrolled case. This paper introduces a method for robust control of synchronous vibration components that can maintain dynamic stability during interaction between the rotor and auxiliary bearings. The controllers are designed to minimize the severity and duration of contact and ensure that the rotor vibration returns to optimal levels, provided that sufficient control force capacity is available. Synthesis of controller gain matrices is based on a linear time-varying system model, which can be derived from either on-line identification routines or theoretical modelling and simulation. The controllers are tested experimentally on a flexible rotor system with magnetic bearings and are shown to restore rotor position control to optimal levels without further contact.

An Active Vibration Control Strategy to Prevent Nonlinearly Coupled Rotor–Stator Whirl Responses in Multimode Rotor-Dynamic Systems

“…The following subsections deal with how to obtain a suitable stabilizing gain matrix K for the proposed controller. Section III.B develops mathematical conditions for global stability of a fixed equilibrium point for the controlled system (10). These conditions may be viewed as minimum requirements for stability.…”

“…Unbalance compensation in a single-disk rotor with nonlinear supports was considered in [9]. Adaptive control of synchronous vibration for a rotor supported by magnetic bearings when contacting with touchdown bearings is covered in [10]. The use of actuated clearance bearings has been proposed for alleviating rub interaction [11], and for recovering stable levitation in magnetic bearing systems [12].…”

Active Magnetic Bearing Online Levitation Recovery through μ-Synthesis Robust Control

“…Much of the existing body of literature in the area of control for relevitation addresses the synchronous disturbance due to TD bearing contact, e.g., [7][8][9]. Therefore, algorithms similar to those for synchronous unbalance compensation have been developed.…”

H-infinity controller design for active magnetic bearings considering nonlinear vibrational rotordynamics

“…Unbalance compensation for a single-disk rotor with nonlinear supports was considered by Inoue et al (2009). Control of synchronous vibration for a rotor supported by magnetic bearings when contacting with clearance bearings was investigated by Cole and Keogh (2003) and Chamroon et al, (2014), while active clearance bearings have also been Cole, Chamroon and Keogh, Mechanical Engineering Journal, Vol.4, No.5 (2017) [DOI: 10.1299/mej. proposed for a similar purpose in (Cade et al, 2010).…”