A novel measurement technique for the alignment of satellite reflectors and feeds: From subsystem to spacecraft and up to final RF testing

Mathur, Pravesh; Rao, C. Koteshwar; Pathak, Swapnil; Gowda, Rudra; Govinda, K.

doi:10.1109/indianaw.2011.6264915

Cited by 1 publication

(1 citation statement)

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“…So, online photogrammetry systems are advantageous over offline ones in real-time spatial data measurement. They are widely used in installation alignment (Mathur et al , 2011), deformation inspection (Hinz et al , 2009; Alemdar et al , 2011), kinematics and kinetics analysis (Baqersad et al , 2015), structural test (Chang and Ji, 2007; Liu et al , 2015), surgery navigation (Ojdanic et al , 2012) and other applications.…”

Section: Introductionmentioning

confidence: 99%

Vision guided geometric regulation of PTC frame structures

Sun

Lü

Dong

et al. 2019

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Purpose Geometric structure error of parabolic trough concentrator (PTC) frame affects the installation accuracy of mirrors and absorber tubes and thus decreases the solar energy concentrating efficiency. Until now, there is no effective method to instruct the assembly and regulation of PTC frames. This paper aims to propose a vision guided method for fast and accurate regulation of mirror and absorber supports to improve the geometric quality of PTC frames. Design/methodology/approach The PTC frame support regulating system consists of a general-purpose online photogrammetry system, frame support measurement adaptors and data analyzing software. First, the positions and angles of all the supports are measured in real time by the online photogrammetric system. Then, the measured positions and angles are aligned to the design reference frame through the transformation calculated by an absorber position constrained nonlinear optimization so as to get the geometric errors and regulating amounts. Finally, a graduated pseudo-color-based visualization method is proposed to assist the manual or automated regulation of PTC frame supports in site. Findings The proposed method does not need to construct a reference system nor specify the rotation attitude of the PTC frame, and it is capable of conducting efficient and accurate regulation on PTC frame assembly line. The method is applied to manual regulation of a light type PTC frame structure. After regulation, the maximum position and angle errors of supports are reduced to less than 0.15 mm and 0.15° respectively and the intercept factor is increased to 97%, which meets the requirement for a qualified PTC concentrator. Originality/value To the authors’ knowledge, this paper is the first to propose a vision guided assembly or regulation method for PTC frame structures. The research uses online photogrammetry system to provide real-time geometric quality information feedback, elaborates the data analysis algorithm and provides the visualization method for accurate and efficient in site regulation. Furthermore, this paper also provides theories, methods and experiences for other applications that use vision guidance for attitude regulation and digital flexible assembly of large equipment.

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