Oil Whip Elimination Using Fuzzy Logic Controller

Abstract

Oil whip is a self-excited subsynchronous vibration which limits the range of operating speed of journal bearings (JBs). JBs have wide range of applications due to their high loading capacity, simple geometry, and lubrication. When the speed of rotation increases, the oil whip instability is excited with a frequency corresponding to the rotor critical speed which causes excessive undesirable vibration. A solution for this instability is implemented through this paper. The control action is implemented through a new integrated bearing device. The bearing consists of JB and electromagnetic actuator (EMA). The oil whip control action is applied through the EMA. A fuzzy logic control algorithm is developed and experimentally applied to a rotor test rig. The controller is suitable to deal with the problems of uncertainties and nonlinearity. The experimental results show the ability of the developed controller to eliminate the oil whip instability when applied to a test rig which simulates industrial rotor through an integrated bearing prototype which was designed and manufactured.