Study on the SCG Rotor's Drift Measurement Based on Differential Capacitance and Transformer Bridge and Analysis of Its Effecting Factors

The levitated superconducting gyroscope (SCG) rotor based on the Meissner effect of superconductive materials may deviate from the center of spherical cavity for various reasons. To measure rotor's drift correctly and then to keep rotor in cavity center are the key to realize rotor's magnetic levitation. The SCG rotor's drift measurement scheme based on the spherical differential capacitance sensors and the transformer bridge, and the relationship of parameters are presented in the paper. This scheme can simultaneously measure the magnitude and the direction of rotor's drift. The factors that affect the SCG rotor's drift measurement precision are analyzed and the simulation results of the effects of these factors on actual system is given as well. It is proved that the distributed capacities of these differential capacitance sensors, the zero potential of rotor and the model error are the major negative factors. The methods to eliminate these negative factors or the adaptation range of the model to ensure linearity relationship between output voltage and rotor's drift are presented.