Comparison of communication architectures for a fiber-positioning spectrograph

Martínez-García, Maria Sofia; Lopez-Colino, Fernando; Garrido, Javier; Glez-de-Rivera, Guillermo; Sánchez, J.; Prada, Francisco

doi:10.1117/1.jatis.5.1.014007

Cited by 2 publications

(1 citation statement)

References 25 publications

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“…The reconfiguration timescales with the number of fibers are thus inefficient for next-generation massive spectroscopy surveys (Cui et al 2012). The most efficient devices are the robotic fiber positioner (RFP) arrays because thousands of fibers can be positioned simultaneously (Martinez-Garcia et al 2019) at the cost of numerous actuators (Smith et al 2004).…”

Section: Introductionmentioning

confidence: 99%

The Calibration of theta-phi Fiber Positioners Based on the Differential Evolution Algorithm

Zhang,

Huang,

Chen

et al. 2024

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Robotic fiber positioner (RFP) arrays are commonly adopted in multiobject spectroscopic instruments. The positioning accuracy is a common but vital issue for RFP as inaccurate fiber placement may heavily affect the observation performance. The calibration of RFP can effectively improve the positioning accuracy. Least-square is a widely used calibration method. However, it has disadvantages, such as sensitivity to the initial values and calculation complexity. To improve the positioning accuracy and reduce the iteration moves, we propose a new calibration method based on the differential evolution algorithm and verify it by calibrating the RFP of the Large Sky Area Multi-Object Fiber Spectroscopy Telescope. We first build the kinematic models of the RFP based on the Denavit–Hartenberg matrix and geometry relationship. Then, we analyze the error components and present the proposed calibration algorithms. The experiments are done with the digital universal tool microscope 19JC and the errors are calculated using the distance between the positions of achieved and target. Results show that the proposed algorithm can achieve higher accuracy than the least-square method and the average positioning accuracy is improved by 78.94% after calibration. Combined with the “pulse reduction” strategy and close-loop compensation, after two moves, the positioners can place the fiber ends within 40 μm of the intended location. The proposed calibration method is also suitable for other similar theta-phi positioners.

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Section: Introductionmentioning

confidence: 99%

The Calibration of theta-phi Fiber Positioners Based on the Differential Evolution Algorithm

Zhang,

Huang,

Chen

et al. 2024

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Collision possibility analysis and collision avoidance for multi-object fibre-fed spectrographs with theta–phi positioners

Zhang

Wang

Liu

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Multi-object spectroscopy has become a valuable technique in numerous modern astronomical facilities. Most spectrographs have thousands of fibre positioners packed at a focal plane with shared working space. Therefore, positioners might collide with each other, which can lead to them being damaged. In this study, we first analysed the types of collisions between hexagonal patterned theta–phi positioners and the possibility of these collisions. Based on this, we proposed a motion planning method by deploying a proposed ‘safety zone’ within the positioner patrol area. Simulated experiments validated that our method could completely solve collisions between positioners with equal arms, such as the Large-sky-Area Multi-Object fibre Spectroscopic Telescope (LAMOST) and the Dark Energy Spectroscopic Instrument (DESI), or between positioners with unequal arms, such as the Multi-Object Optical and Near-infrared Spectrograph (MOONS).

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Comparison of communication architectures for a fiber-positioning spectrograph

Cited by 2 publications

References 25 publications

The Calibration of theta-phi Fiber Positioners Based on the Differential Evolution Algorithm

The Calibration of theta-phi Fiber Positioners Based on the Differential Evolution Algorithm

Collision possibility analysis and collision avoidance for multi-object fibre-fed spectrographs with theta–phi positioners

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