Analysis and Suppression of Limit Cycle Oscillation Induced by CMG Gimbal Friction

Abstract

In recent years, medium-sized satellites that require a large torque are equipped with CMGs. In this study, we deal with limit cycle oscillation induced by CMG gimbal friction. Using a novel describing function that represents the strong nonlinearity of gimbal friction, we analytically predict the amplitude and frequency of the limit cycle. A novel controller, PID+Sign, based on PID control is proposed. The controller estimates the magnitude of the friction force by using an integrator for the gimbal angle error and reduces the limit cycle oscillation by friction compensation. Simulation and experimental results show that the proposed controller can be used to reduce the limit cycle oscillation and achieve accurate attitude control.