The electro-optical tracking system with speedability and maneuverability based on stationary platform is confronted with some problems such as external physical disturbance and detector delay. To obtain better stability, which is the key to achieving high tracking precision, a modified Smith predictor method for inertia stabilization loop control is introduced. This method proposes the Smith predictor control scheme based to compensate delay time caused by the signal filtering of fiber gyroscope sensor in the velocity feedback control, and it utilizes disturbance feedforward control to improve the stability of stabilization platform simultaneously. The design of control structure and analysis of the theory are reported. The experiment results indicate convincingly that the proposed method can effectively improve the bandwidth of velocity closed-loop. Moreover, it can drastically enhance the disturbance suppression performance of tracking platform.

In the mobile optoelectronic tracking system (MOTS) based on charge-coupled device (CCD) and fiber-optic gyroscope (FOG), the tracking performance (TP) and anti-disturbance ability (ADA) characterized by boresight error are of equal importance. Generally, the position tracking loop, limited by the image integration time of CCD, would be subject to a non-negligible delay and low-sampling rate, which could not minimize the boresight error. Although the FOG-based velocity loop could enhance the ADA of the system, it is still insufficient in the case of some uncertain disturbances. In this paper, a feedforward control method based on the results of error and disturbance observation was proposed. The error observer (EOB) based on the CCD data and model output essentially combined the low-frequency tracking feedforward and closed-loop disturbance observer (DOB), which could simultaneously enhance the low-frequency TP and ADA. In addition, in view of the poor low-frequency performance of the FOG due to drift and noise that may result in the inaccuracy of the observed low-frequency disturbance, the FOG-based DOB was used to improve the relatively high-frequency ADA. The proposed method could make EOB and DOB complementary and help to obtain a high-precision MOTS, for in practical engineering, we give more attention to the low-frequency TP and full-band ADA. Simulations and experiments demonstrated that the proposed method was valid and had a much better performance than the traditional velocity and position double-loop control (VPDC).

In the charge-coupled device (CCD) and micro-electro-mechanical system (MEMS) accelerometer based low-cost multi-loop optoelectronic control system (OCS), due to accelerometers’ drift and noise in low frequency, the disturbance suppression (DS) is insufficient. Previously, based on the acceleration and position dual-loop control (ADLC), researchers combined a disturbance observer (DOB) with a virtual velocity loop to make some medium-frequency DS exchange for low-frequency performance. However, it is not optimal because the classic DOB based on accelerometers’ inaccurate signals cannot observe accurate disturbance in low frequency and the velocity based on a CCD and accelerometer time-domain fusion carried the CCD’s delay, resulting in the drop of medium-frequency DS. In this paper, considering the CCD’s advantage in low frequency and the accelerometer’s strength in high frequency, we propose to fuse their signals twice with a modified complementary filter method to respectively acquire an acceleration and velocity. The new acceleration with no drift and less noise but lower bandwidth creates a new acceleration model and is only used in fusion DOB (FDOB), while the velocity with little delay is to build an additional velocity loop. Compared with the traditional DOB enhanced by the time-domain fusion velocity loop, experiments verify that the proposed multiple fusion would apparently enhance the system’s DS, especially in low and medium frequency.

For the high precise tracking control task in quantum communications, this paper introduces a fractional-order control scheme to resolve the confliction between error rejection capacity and stability margin. In the system and controller design, a system preprocessing, including phase margin compensation and controller structure amelioration, is introduced to make the controller realizable. And in order to obtain the global optimum in controller parameter tuning, a visual version method is also imported. This innovative control scheme could effectively equilibrate the system's demands for high error suppression capacity and enough phase margin, and makes it possible for a class of systems’ high precision control. The innovative control method is experimented in an electro-optical system, which could help to obtain a better beam tracking performance in quantum communications.