In this paper, a systematic procedure to design the robust ∞ H fuzzy controller for a nonlinear active magnetic bearing (AMB) system affected by time-varying parametric uncertainties is presented. First, the continuous-time Takagi-Sugeno (T-S) fuzzy model is employed to represent the nonlinear AMB system. Next, based on the obtained fuzzy model, sufficient conditions are derived in terms of lin...

Harmonic force and torque, which are caused by rotor imbalance and sensor runout, are the dominant disturbances in active magnetic bearing (AMB) systems. To eliminate the harmonic force and torque, a novel control method based on repetitive control and notch filters is proposed. Firstly, the dynamics of a four radial degrees of freedom AMB system is described, and the AMB model can be described...

For the demand of high speed and high accuracy, the use of active magnetic bearing (AMB) plays a key role in various industries such as clean rooms, compressors and satellites due to their contactless nature. In this research, two other control options for high speed machine were designed based on the optimal output feedback and H∞ output feedback control methods to improve the radical and axia...

This paper explores the experimental issues associated with the implementation of the recently developed generalized complementary flux constraint (GCFC) flux-biasing scheme on a spacecraft reaction wheel that is magnetically suspended by a low-loss active magnetic bearing (AMB). Implementation of the GCFC depends fundamentally on the ability to estimate the electromagnet flux. Once addressed, ...

In the present study, we developed a self-assembled biodegradable polyglutamic acid (PGA)-based formulation of amphotericin B (AmB) and evaluated its in vitro antifungal potential against Candida albicans. The AmB-loaded PGA nanoparticles were prepared in-house and had a mean size dimension of around 98±2 nm with a zeta potential of -35.2±7.3 mV. Spectroscopic studies revealed that the drug pre...

The literature of active magnetic bearing (AMB) technology dates back to at least 1937 when the earliest work that clearly describes an active magnetic bearing system was published by Jesse Beams [1]. Progress on the technology was modest until the late 1970s, when commercial development began to emerge as, for instance, described by Haberman and Liard in 1977 [2]. The state of the art in 1988 ...

The working principle of the motor can cause unbalanced magnetic pull (UMP) between stator and rotor unavoidably. Previous research about nonlinear vibration excited by UMP was focused on supported traditional mechanical bearings or gas bearings. However, levitation is particular due to low rigidity provided active bearing (AMB). amplifies in resonant zone further excites electromagnetic force,...

Conventional Active Magnetic Bearings (AMB) are operated using a bias current (or flux) to achieve greater linearity and dynamic capability. Bias, however, results in undesirable rotating losses and consequent rotor heating. In this paper, optimal control of a magnetic bearing without bias is investigated. A single degree-of-freedom system consisting of a mass and two opposing electromagnets is...

A rotor supported on active magnetic bearings (AMBs) is levitated inside an air gap by electromagnets controlled in feedback. In the event of momentary loss of levitation due to an acute exogenous disturbance or external fault, reestablishing levitation may be prevented by unbalanced forces, contact forces, and the rotor’s dynamics. A novel robust control strategy is proposed for ensuring levit...