Active vibration control of a rotor-bearing system based on dynamic stiffness

Abstract

This paper presents an active vibration control scheme to reduce unbalance-induced synchronous vibration in rotor-bearing systems supported on two ball bearings, one of which can be automatically moved to control the effective rotor length and, as an immediate consequence, the rotor stiffness. This dynamic stiffness control scheme, based on frequency analysis, speed control and acceleration scheduling, is used to avoid resonant vibration of a rotor system when it passes (run-up or coast down) through its first critical speed. Algebraic identification is used for on-line unbalance estimation at the same time that the rotor is taken to the desired operating speed. Some numerical simulations and experiments are included to show the unbalance compensation properties and robustness of the proposed active vibration control scheme when the rotor is started and operated over the first critical speed.