High-bandwidth tracking control for visual servo gimbals using phase-compensated Youla parameterization with time delay.

Abstract

This paper proposes a phase-compensated high-order Youla-Kucera (HYK) parameterization method to achieve high-bandwidth tracking control for CCD-based visual servo gimbals under sparse sampling and image time delays. The proposed HYK method develops a novel, to our knowledge, high-order low-pass filter topology that actively reshapes the internal YK branch. By analytically compensating for the phase lag intrinsically introduced by the filtering dynamics, the HYK method permits a substantial extension of the effective Q-filter bandwidth without violating the small-gain stability criterion or amplifying high-frequency measurement noise. A rigorous frequency-domain loop-shaping analysis reveals that the introduced feedforward polynomial injects dynamic complex zeros into the open-loop transfer function, actively shifting the phase trajectory near crossover and thereby preserving adequate stability margins under increased bandwidth conditions. Experimental results on a dual-axis inertial gimbal testbed indicate that the proposed method can be easily implemented and exhibits excellent performance in tracking accuracy and disturbance rejection.