A review on control methodologies of disturbance rejections in optical telescope

Tang, Tao; Niu, Shuaixu; Ma, Jian; Qi, Bo; Ren, Guanghui; Huang, Yongmei

doi:10.29026/oea.2019.190011

Cited by 20 publications

(6 citation statements)

References 43 publications

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“…It has been taken in a lot of fields into use, such as target tracking, laser communication, adaptive optics [1]- [4]. The main task of the optoelectronic tracking system is line-of-sight (LOS) tracking, and line-of-sight tracking uses the image sensor to capture dynamic target information to close the loop in real-time [5]. To attain better disturbance overcome and tracking performance of the optoelectronic tracking system, people have proposed a great diversity of LOS tracking methods, such as PID [6], speed delay compensation [7], and disturbance observer based on multi-loop feedback control [8].…”

Section: Introductionmentioning

confidence: 99%

Line of Sight Tracking Method Based on Feedback Linearization and Command Planning

Guo

Xie²,

Chen³

2023

J. Phys.: Conf. Ser.

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When the target just enters the field of view of the optoelectronic tracking system, there is a big pointing deviation. If the closed-loop control is directly performed at this time, overshoot or even oscillation will occur, which will easily cause the target to leave the field of view again. At present, most control algorithms are concerned about enhancing the steady-state tracking precision of the system, but seldom consider the transient performance of the system. In this paper, a new definition of pointing deviation is given, in addition, the model of the line-of-sight (LOS) tracking system is realized. On this basis, a method based on feedback linearization is raised, which can compensate measurable disturbance. For both transient response and steady-state performance, a new LOS planning method is presented, which accomplishes the planning and design of the target motion trajectory on the imaging plane. It can be able to avoid the target departing from the field of view and speed up the system response based on fixed control parameters. Through the analysis of experimental results, it can be indicated that the LOS tracking method proposed in this paper can availably promote the transient performance of the system and is existent of real value.

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Section: Introductionmentioning

confidence: 99%

Line of Sight Tracking Method Based on Feedback Linearization and Command Planning

Guo

Xie²,

Chen³

2023

J. Phys.: Conf. Ser.

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“…Tip-tilt vibrations induced by platform moving, equipment vibration, wind shaking which exhibited complexity in terms of frequency and amplification, and beam jitter in optical link affect the imaging quality and even damage the closed-loop stability [4]- [6]. Furthermore, the long exposure time required for a better signal-to-noise ratio (SNR) images brings amounts of time delay [7], [8], which extremely restricts the closed-loop bandwidth, which makes the highfrequency disturbance suppression beyond control bandwidth become a technical barrier [9], [10]. Developing new control algorithms to suppress disturbance, especially high-frequency disturbance, is necessary.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, these control methods achieve good results in low-frequency disturbance suppression. Nevertheless, the inaccurate identification of the system model and the disturbance model could reduce the effectiveness of disturbance suppressions and even damage the system stability in the high-frequency domain [10]. The repetitive digital controller, which can update the control parameters quickly in real-time, is widely used in various high-precision systems, including hard disk drivers, periodic trajectories, and harmonics compensation of power inverters [22]- [24].…”

Section: Introductionmentioning

confidence: 99%

Enhanced Observer-Based Repetitive Control for Tip-Tilt Disturbance Rejections Beyond Control Bandwidth in Optical-Stabilized Systems

Feng

Ruan

et al. 2023

IEEE Photonics J.

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The stabilization and tracking performance of an image-based tip-tilt system is usually deteriorated by tip-tilt vibrations and beam jitter in optical links due to a limited tip-tilt correction bandwidth. This paper proposes an enhanced observer-based repetitive control (OBRC) method to break the bandwidth limitation of the time delay tip-tilt stabilized loop, which achieves high-frequency disturbance rejections beyond control bandwidth even up to Nyquist frequency. The enhanced repetitive controller is fused with the optimized observer based on Youla parameterization, which improves the stability of the closed-loop and reduces the waterbed effect in non-repetitive frequency. Furthermore, the time delay of the closed-loop system could be compensated by the OBRC. Therefore, disturbance suppressions can be transformed into the design of a repetitive controller, which is effective and easy to be used for tip-tilt vibrations and beam jitter suppression. Finally, simulation and experimental results show that the OBRC effectively suppresses the high-frequency disturbance beyond the control bandwidth of the optical-stabilized system.

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“…Zaher M. Kassas derived the optimal control rate of the control system of Extremely large telescopes ELT, and found that H 2 and H ∞ had the best imaging performance in the case of wind disturbance (Zaher & Rober 2012). Tao Tang analyzed and compared the suppression effects of PI, LQG, DFF (disturbance feedforward control) and DOBC (disturbance observer control) on disturbance of different frequencies (Tang et al 2019). Among them, DOBC has a great suppression ability on disturbance.…”

Section: Introductionmentioning

confidence: 99%

Large Telescope Wind Load Estimation with Gradient Segments Superposition and its Servo Control

Xue

Luan

et al. 2023

Res. Astron. Astrophys.

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The wind load influence on the large aperture radio telescope performance has become one of the key factors to further improve its performance in complex environment. Obtaining the wind load distribution on the telescope aperture is very important to estimate its influence and reduce the wind disturbance on the telescope system. The aperture of the radio telescope structure can be as large as 100 m and whilst, the wind load value in the vertical direction normally varied with the height, therefore, the uniform wind load on the aperture assumption is not suitable for the radio telescope with large aperture. In this paper, a gradient segments superposition method for calculating the wind load on the reflecting surface of the large aperture radio telescope has been proposed to improve the calculation accuracy of wind load. The proposed method has been constructed by combining two regional divisions. For the first division, since the wind speed increases with the altitudinal height, reflecting surface has been evenly divided in the altitudinal direction. For the second division, it is assumed that the wind load coefficient of the reflecting surface in different rings are different and then, the reflecting surface has been divided into several uniform rings. This method improves the estimation accuracy significantly for the telescope with larger aperture. For the 110m aperture radio telescope, the wind load estimation results differ by 28%. After that, a structural dynamics model of telescope has been established and a fuzzy PID controller has been designed to reduce wind disturbance. The Root Mean Square Error (RMSE) of telescope pointing under wind disturbance has been reduced by 67.8%. It is suggested that the proposed wind load estimation method has lay a solid foundation for the design of the large telescope system under wind disturbance.

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A review on control methodologies of disturbance rejections in optical telescope

Cited by 20 publications

References 43 publications

Line of Sight Tracking Method Based on Feedback Linearization and Command Planning

Line of Sight Tracking Method Based on Feedback Linearization and Command Planning

Enhanced Observer-Based Repetitive Control for Tip-Tilt Disturbance Rejections Beyond Control Bandwidth in Optical-Stabilized Systems

Large Telescope Wind Load Estimation with Gradient Segments Superposition and its Servo Control

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