Ms. Nirmala Kunwar Profile

Nirmala Kunwar

at Australian Astronomical Optics, Macquarie Univ

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Author

Publications (6)

Proceedings Article | 29 August 2022 Poster + Paper

Vacuum adhesion of Starbug fibre optic positioning robots in high-altitude ground-based astronomy instrumentation

Ellie O'Brien, Jon Lawrence, Celestina Lacombe, Michael Thomakos, Michael Goodwin, James Gilbert, Slavko Mali, Rolf Muller, Nirmala Kunwar, Jahanzeb Zahoor, Lew Waller, Tony Farrell

Proceedings Volume 12182, 1218237 (2022) https://doi.org/10.1117/12.2629158

KEYWORDS: Telescopes, Green fluorescent protein, Observatories, Robots, Fiber optics, Ferroelectric materials, Astronomy, Stellar astronomy, Liquid crystal on silicon, Glasses

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Starbugs are self-motile fibre optic positioning robots developed by AAO-MQ. MANIFEST (MANy Instrument FibrE SysTem) is a facility class Instrument which will operate up to 900 Starbugs on the Giant Magellan Telescope (GMT). The FOBOS (Fibre-Optic Broadband Optical Spectrograph) Fibre Positioner is a facility class Instrument which will operate up to 1800 Starbugs on the Keck Telescope. Starbugs deliver an optical payload to the location of an astronomical object on the telescope focal plane. The Starbugs are made from a pair of concentric Piezoceramic Tubes (PZT), and a high-voltage waveform is applied to the PZT to create an actuation. Staging of the waveform creates successive microsteps, on the order of 3-20 μm each, at a driven frequency of 100Hz. The Starbugs are adhered to the Glass Field Plate (GFP) using an ancillary vacuum system, which must provide sufficient adhesion force to maintain the Starbug GFP position in the high-altitude environmental conditions at Mauna Kea (MKO) and Las Campanas Observatory (LCO) sites. The minimum vacuum adhesion requirements to achieve Starbug GFP position were used to specify the vacuum pump flow rate and operational head pressure. The vacuum adhesion requirements were experimentally obtained using the Starbug Test Stand, located in Sydney, Australia. The Starbugs Test Stand vacuum adhesion requirements were parametised for dry air mass flow rate and head pressure, and then corrected for the 95th percentile environmental conditions at MKO and LCO. The vacuum system numerical model was verified by the TAIPAN instrument. When corrected for ambient atmospheric conditions at the UK Schmidt Telescope (Siding Spring Observatory, Australia), the numerical model could predict the steady state vacuum pump speed with 1.29% variation from the measured vacuum pump speed recorded by the TAIPAN Instrument control software. This capability of the numerical model will be used for real-time condition monitoring of the Starbugs Instruments.

Proceedings Article | 29 August 2022 Poster + Paper

Design of the near infrared camera DIRAC for East Anatolia Observatory

Ross Zhelem, Robert Content, Vladimir Churilov, Yevgen Kripak, Lew Waller, Scott Case, Slavko Mali, Rolf Muller, Mario Gonzalez, David Adams, Nick Binos, Timothy Chin, Tony Farrell, Urs Klauser, Yuriy Kondrat, Nirmala Kunwar, Jon. Lawrence, Nuria Lorente, Summer Luo, Erica Mcdonald, Helen McGregor, Vijay Nichani, Naveen Pai, Minh Vuong, Jahanzeb Zahoor, Jessica Zheng, Barnaby Norris, Julia Bryant, Annino Vaccarella, Nick Herrald, James Gilbert, Cahit Yesilyaprak, Bulent Gucsav, Deniz Coker, Onur Keskin, Laurent Jolissaint

Proceedings Volume 12184, 1218440 (2022) https://doi.org/10.1117/12.2629716

KEYWORDS: Sensors, Cameras, Optical filters, Telescopes, Adaptive optics, Lenses, Cryogenics, Mirrors, Image quality, Coronagraphy

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Proceedings Article | 29 August 2022 Poster + Paper

Overall performance of AESOP: the 4MOST fibre positioner

Jurek Brzeski, David Adams, Gabriella Baker, Sufyan Baker, Rebecca Brown, Scott Case, Timothy Chin, Jack Coyne, Tony Farrell, Peter Gillingham, Ellen Houston, Urs Klauser, Yevgen Kripak, Nirmala Kunwar, Jon Lawrence, Slavko Mali, Wojtek Maslak, Helen McGregor, Rolf Muller, Vijay Nichani, Naveen Pai, Ellie O'brien, Will Saunders, Scott Smedley, Sudharshan Venkatesan, Lew Waller, Jahanzeb Zahoor, Jessica Zheng

Proceedings Volume 12184, 121846M (2022) https://doi.org/10.1117/12.2627900

KEYWORDS: Spine, Actuators, Fiber science, Telescopes, Tolerancing, Metrology, Galactic astronomy, Calibration, Assembly tolerances, Spectrographs

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Proceedings Article | 29 August 2022 Poster + Paper

AESOP, the 4MOST fibre positioner: engineering principles

Jurek Brzeski, Dave Adams, Gabriella Baker, Sufyan Baker, Rebecca Brown, Scott Case, Timothy Chin, Jack Coyne, Tony Farrell, James Gibson, Peter Gillingham, Ellen Houston, Urs Klauser, Yevgen Kripak, Nirmala Kunwar, Jon Lawrence, Slavko Mali, Wojtek Maslak, Helen McGregor, Rolf Muller, Vijay Nichani, Naveen Pai, Ellie O'brien, Will Saunders, Scott Smedley, Sudharshan Venkatesan, Lew Waller, Jahanzeb Zahoor, Jessica Zheng

Proceedings Volume 12184, 121846N (2022) https://doi.org/10.1117/12.2627903

KEYWORDS: Spine, Telescopes, Tolerancing, Assembly tolerances, Interfaces, Metrology, Kinematics, Assembly equipment, Sensors, Manufacturing

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Proceedings Article | 29 August 2022 Presentation + Paper

MANIFEST@GMT science overview: a multi-interface, multi-mode instrument science and simulations

Tayyaba Zafar, Jonathan Lawrence, Jessica Zheng, David Adams, Vitor Hartmann, Celestina Lacombe, Michael Goodwin, Nuria Lorente, Ellie O'Brien, Will Saunders, Helen McGregor, Lew Waller, Nirmala Kunwar, Daniel Faes, Jennifer Marshall, Darren DePoy, Alexandar Ji, Dennis Zaritsky, Casey Papovich, Steven Finkelstein, Andrew Szentgyorgyi, Roderik Overzier, Kyler Kuehn, Luca Cortese, Scott Croom, Sarah Martell, Matthew Colless, Anilkumar Mailvaganam, Andrew Hopkins, Magda Arnaboldi, Céline Péroux, Christian Johnson

Proceedings Volume 12184, 1218417 (2022) https://doi.org/10.1117/12.2628142

KEYWORDS: Galactic astronomy, Spectrographs, Stars, Interfaces, Telescopes, Polarimetry, Kinematics, Radio astronomy, Gamma radiation, Device simulation

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Proceedings Article | 26 August 2022 Poster + Paper

A Starbug's life: a material trade study using fatigue life criteria for high-altitude robotic fibre positioning instruments

Ellie O'Brien, Jon Lawrence, Celestina Lacombe, Michael Thomakos, Michael Goodwin, James Gilbert, Slavko Mali, Rolf Muller, Nirmala Kunwar, Jahanzeb Zahoor, Lew Waller, Tony Farrell

Proceedings Volume 12182, 1218236 (2022) https://doi.org/10.1117/12.2629152

KEYWORDS: Ferroelectric materials, Green fluorescent protein, Electrodes, Telescopes, Mechanics, Safety, Roads, Observatories, Robots, Robotics

Read Abstract +

Starbugs are self-motile fibre optic positioning robots developed by AAO-MQ. The MANIFEST (MANy Instrument FibrE SysTem) is a facility class Instrument which will operate up to 900 Starbugs on the Giant Magellan Telescope (GMT). The FOBOS (Fibre-Optic Broadband Optical Spectrograph) Fibre Positioner is a facility class Instrument which will operate up to 1800 Starbugs on the Keck Telescope. The Starbugs deliver an optical payload to the location of an astronomical object on the telescope focal plane. The Starbugs are made from a pair of concentric Piezoceramic Tubes (PZT), and a high-voltage waveform is applied to the PZT to create an actuation. Staging of the waveform creates successive microsteps, on the order of 3-20 μm each, at a driven frequency of 100Hz. The Starbugs are adhered to the Glass Field Plate (GFP) using an ancillary vacuum system. The Starbugs have an airtight vacuum sealing component between the PZT and the GFP, called Slippers, which serve as a traction surface against the polished GFP. The Slippers set the science fibre focus offset, which has functional requirements that trace to Observatory level requirements. The Slipper components are subject to non-zero centred fully reversed fatigue loading due to the combined load case of the vacuum induced compression and the shear load of the PZT actuation as the Starbug completes the step. The contact interface between the Slipper and the GFP is subject to surface fatigue and functions as a sacrificial wear surface to ensure the longevity of both the PZT and the optical payload. The fatigue life behaviour of the Slipper, with particular interest on this interface, was defined using industry standard methods and informed the trade study to select the appropriate material for the Slippers to survive a nominal period on-sky (fatigue life). The trade study terms were vacuum sealing ability as a function of mechanical hardness versus fatigue life (108 cycles). Several suitable materials were identified and will be physically prototyped, with results reported in this manuscript.

Showing 5 of 6 publications

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