Robust Vibration Control Using Superconductor as Levitation Device and Velocity Sensor

A new method of using a high Tc superconductor as two functions of levitation device and velocity sensor is introduced. The levitated object is controlled with an electromagnet using the measured velocity signal, that is the system involves a hybrid magnetic levitation of superconductor pinning effect and active magnetic bearing. The experimental setup of a single degree-oj-freedom system is made using a cantilever beam. A coil is wound around a permanent magnet which is used as a velocity sensor. This coil produces electromotive voltage in proportion to relative velocity. A simple velocity fee dback measured by the proposed technique well improves the damping property of the levitated object. However, the vibration isolation property from the base is decreased. In order to insulate against vibration from the base and to reduce vibration from external force an R:x> optimum controller is designed. The accerelation of the levitated object is also measured and used as well as the relative velocity. The Hoo co ntroller with two input signals is applied to the experimental setup. The 'results obtained are showing good vibration reduction and isolation property and indicating good robust stability.