Coupling Theory Analysis And Experimental Research On A Magnetic Suspended Spindle System

The force coupling, moment coupling and magnetic coupling etc are natural characteristics in a magnetic suspended rotor system. In the former study on a magnetic suspended rotor system, few studied on diversified couplings at the same time, neither performed an experimental test and verify. In the most practical applications of a magnetic suspended rotor the affect of coupling is neglected. The neglecting is satisfied while the geometrical dimensions of a magnetic suspended rotor are relatively large. But as the decreasing of the geometrical dimensions of a magnetic suspended rotor the affect of coupling is getting prominent. In the application of tiny magnetic suspended rotor, such as magnetic suspended hard disk drive, tiny magnetic suspended gyroscope etc, the neglecting of the affect of coupling is no longer appropriate. From the view of this studying on diversified couplings in a magnetic suspended rotor system and performing an experimental text and verify have double significance in both theoretically and practically.The paper studied on diversified couplings in a magnetic suspended rotor system. Such as the magnetic coupling between the poles of a radial magnetic bearing, the force coupling between horizontal coordinate x and vertical coordinate y within a radial magnetic bearing, the moment coupling between the front and the rear radial magnetic bearings, the signal coupling caused by offset arrangement of the displacement sensors, and the influence on the signal coupling caused by thermo-drift of the sensor. The formulas for coupling calculation are derived. At the same time the relationship between the coupling and the structure parameters of a magnetic suspended rotor is also studied. In order to evaluate the influence of the couplings the coupling coefficients are brought in. A dynamics formula for magnetic suspended rotor taking coupling influence in consideration is established on the bases of research mentioned above.The principle of no-superposition characteristics for the magnetic force within a radial magnetic bearing is brought forward. I.e. a magnetic force is not equal to the superposition of the force in horizontal coordinate x and the force in vertical coordinate y within a radial magnetic bearing. The principle of no-superposition characteristics makes the ornerstone for verifying characteristics of coupling in a magnetic suspended rotor system. From the principle an experimental device is designed to test and verify the characteristics of coupling for a magnetic suspended rotor system. The experiment result matched the theory well. The experimental data provide foundation for structure design, coupling characteristic demarcate, system modeling and controlling.The paper studied coupling characteristics of a tiny magnetic suspended rotor. The supporting principle for a disk-like magnetic suspended rotor is also studied and it's criterion and the way of state information acquiring is brought forward at same time.