Mr. Junji Takaki Profile

Junji Takaki

at Mitsubishi Electric Corp

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Author

Publications (6)

Proceedings Article | 29 August 2022 Presentation + Paper

Seismic isolation system design and performance of TMT telescope structure

Masahiro Sugimoto, Atsushi Kato, Junji Takaki, Masaki Tabata, Tomoya Hattori, Amir Sadjadpour, Brady Espeland, Hugh Thompson, Satoru Sofuku, Yutaka Ezaki, Noboru Kawaguchi, Tomonori Usuda, Hiroshi Kusumoto, Masao Saito, Hiroshi Terada, Seiichi Tazawa, Kyle Kinoshita

Proceedings Volume 12182, 1218216 (2022) https://doi.org/10.1117/12.2631409

KEYWORDS: Telescopes, Earthquakes, Finite element methods, Observatories, Prototyping, Thirty Meter Telescope, Astronomy

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Proceedings Article | 13 December 2020 Presentation + Paper

High precision machining in TMT (Thirty Meter Telescope) structure manufacturing

Kenji Kamikawa, Akihiro Nagai, Takuya Ashida, Kazuhiko Tani, Tatsuya Nariyama, Takayuki Ishida, Junji Takaki, Noboru Kawaguchi, Makoto Endo, Yutaka Ezaki, Tomonori Usuda, Masao Saito

Proceedings Volume 11445, 114451R (2020) https://doi.org/10.1117/12.2560614

KEYWORDS: Thirty Meter Telescope, Manufacturing, Temperature metrology, Surface finishing, Large telescopes, Surface roughness, Abrasives

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Proceedings Article | 27 July 2016 Paper

Overview of key technologies for TMT telescope structure

Yutaka Ezaki, Atsushi Kato, Tomoya Hattori, Yusuke Saruta, Satoru Sofuku, Toshitaka Nakaoji, Noboru Kawaguchi, Junji Takaki, Yasushi Horiuchi, Masaki Haruna, Masaki Tabata, Yoshihiro Hosokawa, Hiroshi Kusumoto, Tomonori Usuda

Proceedings Volume 9906, 99060Y (2016) https://doi.org/10.1117/12.2233847

KEYWORDS: Telescopes, Optical instrument design, Control systems, Mirrors, Optical instrument design, Earthquakes, Control systems, Thirty Meter Telescope, Computer aided design, Bridges, Astronomy, Observatories

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Proceedings Article | 27 July 2016 Paper

Segment handling system prototype progress for Thirty Meter Telescope

Satoru Sofuku, Yutaka Ezaki, Noboru Kawaguchi, Toshitaka Nakaoji, Junji Takaki, Yasushi Horiuchi, Yusuke Saruta, Masaki Haruna, Ieyoung Kim, Kazuhiko Fukushima, Yukiyasu Domae, Toshiyuki Hatta, Shinya Yoshitake, Hayato Hoshino

Proceedings Volume 9906, 99062Y (2016) https://doi.org/10.1117/12.2233856

KEYWORDS: Thirty Meter Telescope, Control systems, Telescopes, Machine vision, Mirrors, Prototyping, Bridges, Cameras, Computer aided design, Observatories

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Proceedings Article | 27 July 2016 Paper

Force control technology of segment mirror exchange robot for Thirty Meter Telescope (TMT)

Masaki Haruna, Ieyoung Kim, Kazuhiko Fukushima, Satoru Sofuku, Toshitaka Nakaoji, Junji Takaki, Yusuke Saruta, Noboru Kawaguchi, Yasushi Horiuchi, Yutaka Ezaki

Proceedings Volume 9906, 99062Z (2016) https://doi.org/10.1117/12.2235091

KEYWORDS: Thirty Meter Telescope, Mirrors, Control systems, Prototyping, Control systems, Sensors, Video, Interfaces, Motion measurement, Computer programming, Calibration

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Proceedings Article | 22 July 2014 Paper

Preliminary design study of the TMT Telescope structure system: overview

Tomonori Usuda, Yutaka Ezaki, Noboru Kawaguchi, Kazuhiro Nagae, Atsushi Kato, Junji Takaki, Masaki Hirano, Tomoya Hattori, Masaki Tabata, Yasushi Horiuchi, Yusuke Saruta, Satoru Sofuku, Noboru Itoh, Takeharu Oshima, Takashi Takanezawa, Makoto Endo, Junji Inatani, Masanori Iye, Amir Sadjadpour, Mark Sirota, Scott Roberts, Larry Stepp

Proceedings Volume 9145, 91452F (2014) https://doi.org/10.1117/12.2055767

KEYWORDS: Telescopes, Optical instrument design, Computer aided design, Mirrors, Electroluminescence, Control systems design, Control systems, Earthquakes, Safety, Thirty Meter Telescope

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We present an overview of the preliminary design of the Telescope Structure System (STR) of Thirty Meter Telescope (TMT). NAOJ was given responsibility for the TMT STR in early 2012 and engaged Mitsubishi Electric Corporation (MELCO) to take over the preliminary design work. MELCO performed a comprehensive preliminary design study in 2012 and 2013 and the design successfully passed its Preliminary Design Review (PDR) in November 2013 and April 2014. Design optimizations were pursued to better meet the design requirements and improvements were made in the designs of many of the telescope subsystems as follows: 1. 6-legged Top End configuration to support secondary mirror (M2) in order to reduce deformation of the Top End and to keep the same 4% blockage of the full aperture as the previous STR design. 2. “Double Lower Tube” of the elevation (EL) structure to reduce the required stroke of the primary mirror (M1) actuators to compensate the primary mirror cell (M1 Cell) deformation caused during the EL angle change in accordance with the requirements. 3. M1 Segment Handling System (SHS) to be able to make removing and installing 10 Mirror Segment Assemblies per day safely and with ease over M1 area where access of personnel is extremely difficult. This requires semi-automatic sequence operation and a robotic Segment Lifting Fixture (SLF) designed based on the Compliance Control System, developed for controlling industrial robots, with a mechanism to enable precise control within the six degrees of freedom of position control. 4. CO₂ snow cleaning system to clean M1 every few weeks that is similar to the mechanical system that has been used at Subaru Telescope. 5. Seismic isolation and restraint systems with respect to safety; the maximum acceleration allowed for M1, M2, tertiary mirror (M3), LGSF, and science instruments in 1,000 year return period earthquakes are defined in the requirements. The Seismic requirements apply to any EL angle, regardless of the operational status of Hydro Static Bearing (HSB) system and stow lock pins. In order to find a practical solution, design optimization study for seismic risk mitigation was carried out extensively, including the performing of dynamic response analyses of the STR system under the time dependent acceleration profile of seven major earthquakes. The work is now moving to the final design phase from April 2014 for two years.

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