Enhanced 2-axis Gimbal Stabilization Control via a Hybrid Coordinate System Approach With Disturbance Observer

Abstract

This paper proposes the line of sight (LOS) orientation cascade-type stabilization controller of a twoaxis gimbal with a novel integrated coordinate approach, the hybrid coordinate system (HCS), which combines joint and inertial coordinate frames. A robust controller is designed using this system, employing feed-forward (FF) stabilization and a disturbance observer (DOB) for each joint within the new coordinate system to eliminate external disturbances, internal joint friction, coupling torque, and model uncertainty. Controller parameters and controllable frame designs are determined through HCS model with multi-sensor configuration. Additionally, a filter is designed to address the drift issue that may occur in the given system. To verify the proposed control algorithm, a controller analysis and comparison with other controllers are conducted through actual external environment experiments. The HCS approach showed improved LOS stabilization performance compared with other methods.