Dynamic Characteristics Analysis Of Hollow Be Rotor For Electrostatic Suspended Gyroscope

Electrostatic suspended gyroscope(ESG) has high navigation accuracy and strong anti-interference capacity. It has been widely used in aerospace and navigation. As the kernel component of ESG, the rotor suspended in a vacuum spherical cavity can free motion. For guarantee rotor’s machining precision, it grinded by the four-shaft-ball lapping machine which is one of the best methods for machining high precision ball.By the limit of equipment machining precision and operator’s skill levels, the hollow Be rotor exists eccentric distance and sphericity error. Eccentric distance can be divided into axial direction which will cause rotor’s drift and radial direction which will cause vibration and attenuation of rotary speed. Sphericity error will cause rotor’s drift and attenuation of rotary speed. Therefore, the value of sphericity error and eccentric distance should be controlled in a permissive range.To facilitate analysis, uses the harmonic coefficients characterize the sphericity error. It has established the kinematic balance equations of gas floating and electrostatic suspension respectively. The equations are solved by Matlab software, and draw the movement curves of the rotor with time. Analyze the affect of the initial position, eccentric distance and harmonic coefficients to the kinematic characteristics of rotor.Analysis shows that the motion is attenuated when the rotor supported by gas. During the rough finish and semi finishing stage, eccentric distance is large and the initial conditions have less impact on balance cycle. When the eccentric distance e≤0.082μm, the initial conditions have great affect on balance cycle which change irregularly. Under the conditions of electrostatic suspension, the larger the eccentric distance, the faster the rotor attenuate. But with the improvement of the machining accuracy, the eccentric distance is smaller. The influence on the damped motion of the rotor can be negligible when the eccentric distance e≤0.051μm. The larger the harmonic coefficient, the bigger the disturbing torque and the affect on motion curve of the rotor will become greater.