A 2005 TRC report presents imbalance response measurements of a hollow test rotor supported on bump-type gas foil bearings. The top speed of the tests is 25 krpm, the limit of the drive router motor. The 2005 measurements show the gas foil bearings are prone to subsynchronous whirl with amplitudes of motion exacerbated by the imbalance condition of the rotor, i.e. a forced nonlinearity. Present...

We address the problem of H 1 gain-scheduling of a magnetic bearing/rotor system with the speed of the rotor being the scheduling parameter. The rotor exhibits signiicant gyroscopics. As a result, the plant dynamics change with the rotor speed. Recent results in the theory of LPV systems can be used to design robust, gain-scheduled controllers for such a system. As opposed to traditional gain-s...

A vector control of an induction motor by an estimated speed using an extended Kalman filter is proposed. With this method, the states are composed of stator current and rotor flux. The rotor speed is regarded as a parameter, and the composite states consist of the original states and the rotor speed. The extended Kalman filter is employed to identify the speed of an induction motor and rotor f...

This paper presents an active vibration control scheme to reduce unbalanceinduced 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 sche...

We address the problem of H gain scheduling of a magnetic bearing rotor system with the speed of the rotor being the scheduling parameter The rotor exhibits signi cant gyroscopics As a result the plant dynamics change with the rotor speed Recent results in the theory of LPV systems can be used to design robust gain scheduled controllers for such a system As opposed to traditional gain schedulin...

In this paper, the effectiveness of stiffness and damping of bearing is investigated on the natural frequencies of the rotor-bearing system. The rotor-bearing system consists of a shaft, two bearings and a disk between two bearings. Parallel spring-damper in horizental and vertical directions is considered for modeling the stiffness and damping of bearings. The gyroscopic effect is also conside...

This paper presents a speed sensorless rotor flux estimation algorithm in a vector controlled induction motor drive. The proposed method is based on observing a newly defined state which replaces the unknown terms containing rotor flux and speed on right hand side of the state equation of the motor. A new mathematical model of the motor is derived after introducing the above mentioned sate. Rot...

The paper proposes a mechanical model of SFD-sliding bearing flexible rotor system, employing RungeKutta method to tackle nonlinear differential equation, thus acquiring the dynamic response and the unbalanced response curve. Results obtained show the route of flexible rotor system from stable periodic motion to chaos state is: periodic motion—quasi-periodic motion—chaos —period doubling bifurc...

In this paper, one presents a transient state performance optimization of vectorcontrolled induction motor (IM) drives operating in the field-weakening region. The vector control scheme, based on the rotor flux field-orientation (RFOC), is considered to ensure maximum torque motor operation regime. Although in the high speed region, the measure of rotor speed and the sensitivity to parameters e...

This paper presents the modeling of a four rotor vertical take-off and landing (VTOL) unmanned air vehicle known as the quad rotor aircraft. The paper presents a new model design method for the flight control of an autonomous quad rotor. The paper describes the controller architecture for the quad rotor as well. The dynamic model of the quad-rotor, which is an under actuated aircraft with fixed...