In recent years many researchers have been focused on ACTIVE MAGNETIC BEARING (AMB) systems. AMB offers advantages such as, contact less and friction free operation, excellent performance over a wide range of temperature, no need for lubricant and longer life. Technology of MAGNETIC BEARINGs can be considered as a new field of research in Iran. This paper presents design, manufacturing and control of a MAGNETICally levitation system with successful operation. This research concluded with documentation of the AMB technology which is prerequisite for earning the technology of ACTIVE MAGNETIC systems (AMS) and paves the way to develop it.

Choosing the appropriate end supports has been great importance in rotating machinery. The mechanical BEARINGs (ball and journal) are more popular types of supports that used in rotating systems. However, the rub-impact between the rotor and BEARING is main disadvantage of these types of BEARINGs. Whereby, the ACTIVE MAGNETIC BEARINGs have been developed recently that removes the rub-impact, but induces new nonlinear factors that affect the dynamical behavior of system. An unbalanced disk is mounted on the shaft. The rotor is modeled as three masses and 8 D.O.F. The governing equations are extracted in form of nonlinear coupled ordinary differential equations. The influence of MAGNETIC BEARING stiffness on the chaotic behavior of a flexible rotor supported by ACTIVE MAGNETIC BEARINGs is investigated. The bifurcation diagrams, phase planes, power spectra, Poincare map and maximum lyapanov exponents are used to analyze the response under different operational conditions. The numerical results shows a rich variety of nonlinear behavior including periodic, sub-periodic, quasi-periodic and chaotic vibration due to ACTIVE MAGNETIC.

Crack fault of rotor is one of the most prominent problems faced by MAGNETIC BEARING rotor system. In order to improve the safety performance of this kind of machinery, it is necessary to research the vibrat ion characteristics of MAGNETIC BEARING cracked rotor system. In this paper, the st iffness model of the crack shaft element was established by the st rain energy release rate (SERR) theory. The mathematical model of PD controller of AMBs cracked rotor system is based on the finite element method. The vibration characteristics of PD controller of AMBs rotor system were examined in the test rig under crack depth of rotor. The spectrum of vibration characteristics were detected in the AMBs cracked rotor system. The results of experiments showed that the 2× and 3× harmonic components can be used for fault diagnosis of crack fault of AMBs rotor systems under PD controller of AMB.

A typical passive MAGNETIC BEARING has been modeled and analyzed for its performance characteristics.The MAGNETIC BEARING studied in this work comprised of a Shaft, inner magnets sleeved over the shaft, and outer MAGNETIC rings. A detailed analysis has been perform on the force exerted by a permanent magnet on the shaft nurture to restore the shaft to its equilibrium position when an eccentricity is induced between the magnet and the shaft. A relation between the force exerted and the displacement of the shaft from its equilibrium position has been developed hence determining a specific stiffness value.

In this paper, the three-axis MAGNETIC attitude control using PD and LQR control laws have been studied in a lab environment. Evaluation of the MAGNETIC attitude control with this control laws is done by a "three degrees of freedom air-BEARING simulator". Developed dynamic and kinematic equations to be used in actual simulator are evaluated by open loop test. Then control laws evaluated by comparing close loop simulation and laboratory test. Due to the inherent simulator limitations, MAGNETIC attitude control only possible in the yaw axis. Laboratory test results indicate the improved and accurate performance of LQR control law for most satellite missions. Therefore by generalized LQR controller, three-axis simulation was performed for a satellite.

Maxwell 3D of Ansoft software were used for this study. Ansoft's solutions are based on a more general program using Maxwell's equations. A simple analysis has been done for calculating the MAGNETIC force interacted between two magnets of similar poles facing each other. The modeling in Anosoft has been described.