A novel micro-vibration model for control moment gyros to predict nonlinear contact characteristics of high-speed bearings considering a soft mounted configuration

The installation of isolation platforms is essential for mitigating micro-vibrations in control moment gyroscopes (CMGs) and enhancing the manoeuvre performance of agile satellites. High-speed bearings within CMGs are particularly susceptible to failure under varying speeds and dynamic loads. It is crucial to investigate the contact behavior of bearings and the coupling mechanisms of the micro-vibration in a CMG-isolation platform system. This study proposes a micro-vibration model of a single-gimbal CMG-isolation platform with six degrees-of-freedom and analyzes the contact behavior of high-speed bearings. Experimental tests are conducted to validate the accuracy of the dynamical model. The characteristics of the rotor micro-vibration, support forces and moments of high-speed bearings, and contacting behavior of the rolling balls are discussed. The micro-vibrations and support forces and moments can be effectively reduced in the soft mounted configuration. Nonlinear contact forces between the rolling balls and raceways fluctuate significantly leading to a suppression of the high-order harmonic components of rotor micro-vibration when the gimbal rotates at a low speed. This study provides novel insights into the mechanisms of the micro-vibration in CMGs and the model can be applied for reasonable structural optimizations and designs of different kinds of CMG-isolation systems to improve their performance and reliability.