Simply structured controllers for vibration suppression in long rotors

Abstract In this paper suppression of the transient flexural vibrational disturbances in long rotors, with fluid film bearings, is investigated. The rotor described by a series distributed shafts connected lumped discs, and system mounted on bearings. Upon determination dynamic stiffness matrix system, best approximate transfer function description rotor, determined. Initially vibration simple diagonal Proportional + Integral (PI) controllers studied via direct search optimisation techniques PI parameters which exhibit fast found. resulted high integration rate, low proportional gain controller, theoretically provided time. However, it shown that due to strong coupling effect rate integration, closed loop relative stability weak, feasibility controller questionable. Therefore, an alternative first order without action, named “attenuation filter “is suggested can produce stronger produces significant (not full) suppression. multivariable control comprising two sensors magnetic actuators using such attenuation filter, then simulated. response step disturbances, has 95% significantly response. It concluded although may not provide 100% suppression, but more reliable since error, results weak avoided.