Recent testing of a micro autonomous positioning system for multi-object instrumentation

W. A. Cochrane*, D. C. Atkinson, T. E. C. Bailie, C. Dickson, T. Lim, X. Luo, D. M. Montgomery, H. Schnetler, W. D. Taylor, B. Wilson

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)


A multiple pick off mirror positioning sub-system has been developed as a solution for the deployment of mirrors within multi-object instrumentation such as the EAGLE instrument in the European Extremely Large Telescope (E-ELT). The positioning sub-system is a two wheeled differential steered friction drive robot with a footprint of approximately 20 x 20 mm. Controlled by RF communications there are two versions of the robot that exist. One is powered by a single cell lithium ion battery and the other utilises a power floor system. The robots use two brushless DC motors with 125:1 planetary gear heads for positioning in the coarse drive stages. A unique power floor allows the robots to be positioned at any location in any orientation on the focal plane. The design, linear repeatability tests, metrology and power continuity of the robot will be evaluated and presented in this paper. To gather photons from the objects of interest it is important to position POMs within a sphere of confusion of less than 10 μm, with an angular alignment better than 1 mrad. The robots potential of meeting these requirements will be described through the open-loop repeatability tests conducted with a Faro laser beam tracker. Tests have involved sending the robot step commands and automatically taking continuous measurements every three seconds. Currently the robot is capable of repeatedly travelling 233 mm within 0.307 mm at 5 mm/s. An analysis of the power floors reliability through the continuous monitoring of the voltage across the tracks with a Pico logger will also be presented.

Original languageEnglish
Title of host publicationModern Technologies in Space- and Ground-Based Telescopes and Instrumentation II
ISBN (Print)9780819491510
Publication statusPublished - 13 Sept 2012
EventSPIE Astronomical Telescopes + Instrumentation 2012 - Amsterdam, Netherlands
Duration: 1 Jul 20126 Jul 2012

Publication series

NameProceedings of SPIE
ISSN (Print)0277-786X


ConferenceSPIE Astronomical Telescopes + Instrumentation 2012


  • MAPS
  • Micro autonomous robots
  • Multi object spectrometers
  • Robot positioning system

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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