Enhanced Observer Control of a Cubic Stewart Platform With Image Sensor Measurement

Wu, Yun; Zhang, Liangzong; Xu, Tian; Tang, Tao

doi:10.1109/jphot.2022.3206335

Cited by 3 publications

(2 citation statements)

References 34 publications

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“…2) The error-based observation control: An error-based observation control method is proposed to relax the restraint on the time delay for the tip-tilt mirror control subsystem, the essence of which is a type of repetitive control [29], [30]. The control structure of the proposed error-based observation is shown in Fig.…”

Section: A the Design Of The Ccd-based Stewart Platform Control Subsy...mentioning

confidence: 99%

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Image Stabilization of a Model-Following Dual-Stage System With Charge-Coupled Device Measurement

Wu,

Zhang,

Tang

2024

IEEE Photonics J.

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This article develops a charge couple device (CCD)based dual-stage system consisting of cubic Stewart platform and tip-tilt mirror to stabilize the line-of-sight (LOS) for space optical payloads. Due to the conventional offloading strategy needing the accurate characteristic of the CCD and additional position sensor in terms of precision and bandwidth, a novel model-following offloading strategy is presented to achieve the offloading for the dual-stage system. The essence of the proposed strategy is that the following position signal can be estimated through combining the controller output with the model-based estimation of the tiptilt mirror to be offloaded into the Stewart platform. Besides, an error-based observation control technique is introduced to relax the limitations imposed by the low sampling rate of the CCD on closed-loop performance for the tip-tilt mirror loop. This technique reduces reliance on the precise control model and optimizes the tracking performance by the design of an appropriate Q-filter. The simulations and experiments of the dual-stage image stabilization system demonstrate the validity of the presented approach.

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Section: A the Design Of The Ccd-based Stewart Platform Control Subsy...mentioning

confidence: 99%

“…Based on (30), it can be seen that the cut-off frequency 1/ς of Q(s) decreases with the increasing order m. Compared to the original feedback loop, the enhancement of the closedloop performance with the error-based observation control is expressed below…”

Section: Cttm(s)mentioning

confidence: 99%

Image Stabilization of a Model-Following Dual-Stage System With Charge-Coupled Device Measurement

Wu,

Zhang,

Tang

2024

IEEE Photonics J.

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The six-degrees-of-freedom attitude measurement instrument for the large aperture mirror using the prepressing sensors and flexible supporting

Xu,

Li,

et al. 2023

Review of Scientific Instruments

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To achieve precise measurement of a large aperture mirror, a six-degrees-of-freedom (6-DOF) measurement instrument is designed to monitor and calculate the real-time attitude of the mirror. Magnetoelectric displacement sensors are prepressed, and a flexible sensor supporting is designed to achieve high-accuracy measurement. The relationship between 6-DOF displacements of the mirror and the six sensor values can be obtained using the coordinate system transformation and Jacobian matrix. The Newton’s iteration method is used to decouple the strong coupling measurement system, and 6-DOF displacements are obtained. The displacements directly measured by using laser sensors are compared with the calculated values in the experiments, the minimum average error of the measured displacement is 1.87%, and the mean difference of the displacement is 0.43 µm.

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Dynamics Modeling and Modal Space Control Strategy of Ship-Borne Stewart Platform for Wave Compensation

Chen

Wen

Xiaochuan

et al. 2023

Journal of Mechanisms and Robotics

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The ship-borne Stewart platform can compensate for the six-degree-of-freedom motion generated by the ship, which improves the reliability and safety of offshore operations and increases the executable window period. The heavy and off-center load of the gangway significantly influences the high-precision compensation control of the platform. Besides, the gangway assembled on the platform vibrates easily due to its low natural frequency which requires high dynamic performance of the compensating. To deal with the problem mentioned, the modal space control strategy is introduced to fully consider the inertia characteristics. Firstly, based on Kane's method, the complete dynamic model considering the ship's motion and actuator inertia is established. Then, the modal space PD controller (MSPDC) and the modal space sliding mode controller (MSSMC) are designed based on modal theory. Finally, simulations are carried out to show the advantages of the proposed model and the advantages of proposed controllers in compensation accuracy and anti-interference ability. Furthermore, The Significant Compensation Rate (SCR) is proposed to evaluate the six-DOF compensation accuracy. Compared with the PD controller with gravity compensation (PDCGC), the position SCR of MSSMC is increased from 95.37 % to 99.28 %, and the angle SCR from 85.57 % to 99.65 %.

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Enhanced Observer Control of a Cubic Stewart Platform With Image Sensor Measurement

Cited by 3 publications

References 34 publications

Image Stabilization of a Model-Following Dual-Stage System With Charge-Coupled Device Measurement

Image Stabilization of a Model-Following Dual-Stage System With Charge-Coupled Device Measurement

The six-degrees-of-freedom attitude measurement instrument for the large aperture mirror using the prepressing sensors and flexible supporting

Dynamics Modeling and Modal Space Control Strategy of Ship-Borne Stewart Platform for Wave Compensation

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