Stabilization and tracking precision improved based on disturbance observer

Based on the kinematics of semi-strapdown seeker, the framework coordinate of the semi-strapdown seeker is established and the optical axis stabilization equation of semi-strapdown seeker is deduced based on product of exponential (POE) formula. The stabilization control principle block diagram of semi-strapdown seeker is shown based on the stabilization equation. The main influence factors of the stability precision are pointed out, such as friction disturbance, velocity measurement noise and missile disturbance. For the sake of improving the stabilization precision and tracking precision, disturbance observer was proposed in the inner loop of semi-strapdown seeker servo-control system. The low frequency external disturbance and high frequency velocity measurement noise are effectively restrained by the disturbance observer as shown in hardware-in-loop simulation, and optical axis stabilization precision and tracking precision are greatly improved.