Decoupling Control and Omnidirectional Stabilization of Line-of-Sight for a 3-DOF Optoelectronics System with Mirror

This paper proposes a Line-of-Sight (LOS) inertial stabilization and pointing control strategy for a 3-DOF Optoelectronics system with mirror. The inertia angular rates of azimuth, elevation and roll of LOS cannot be measured by gyro directly due to the coordinate of LOS is not physically existed. According to the geometric relationship of three gimbals and the law of light reflection, the kinematic equation of LOS is deduced, and an improved installation solution of 4 gyros is proposed to measure the motion of LOS. Then, the LOS system multi-input multi-output (MIMO) model can be established by decoupling 3 orthogonal inertia angular rates of LOS, the angular motions of 3 axis motors, and the measured angular rates of 4 gyros. In addition, by adopting the fully decoupled 3 axis joint control method, the influence of angular disturbances to LOS inertia motion can be mitigated, then 3-DOF inertial stability and precise pointing control of the LOS can be achieved. Furthermore, a dimension reduction control method is proposed to avoid motor over-speed near the gimbal lock orientation, achieve the omnidirectional stabilization of LOS. Simulation and experimental results verify the advantages of the proposed method.