Control Design for Trajectory Tracking and Stabilization of Sensor LOS in an Inertially Stabilized Platform

Optical sensors are often mounted on moving platforms to aid in a variety of tasks like data collection, surveillance and navigation. This necessitates the precise control of the inertial orientation of the optical sensor line-of-sight (LOS) towards a desired stationary or mobile target. A two-axes gimbal assembly is considered to achieve this control objective which can be decomposed into two parts - stabilization and tracking. A novel state space model is proposed based on the dynamics of a two-axes gimbal system. Using a suitable change of variables, this state space model is transformed into an LTI system. Feedback linearization based control laws are proposed that achieve the desired objectives of stabilization and tracking. The effectiveness of these control laws are demonstrated via simulation in MATLAB based on a typical model of a two-axes gimbal system.