Design, development, and validation of a segment support actuator for the prototype segmented mirror telescope

Prasanna Gajanan Deshmukh, Amaresh Mandal, Padmakar S. Parihar, Dayananda Nayak, Deepta Sundar Mishra

Research output: Contribution to journalArticle

Abstract

Segmented mirror telescopes (SMT) are built using several small hexagonal mirrors positioned and aligned by the three actuators and six edge sensors per segment to maintain the shape of the primary mirror. The actuators are responsible for maintaining and tracking the mirror segments to the desired position, in the presence of external disturbances introduced by wind, vibration, gravity, and temperature. The present paper describes our effort to develop a soft actuator and the actuator controller for prototype SMT at Indian Institute of Astrophysics, Bangalore. The actuator designed, developed, and validated is a soft actuator based on the voice coil motor and flexural elements. It is designed for the range of travel of ±1.5 mm and the force range of 25 N along with an offloading mechanism to reduce the power consumption. A precision controller using a programmable system on chip (PSoC 5Lp) and a customized drive board has also been developed for this actuator. The close loop proportional-integral-derivative (PID) controller implemented in the PSoC gets position feedback from a high-resolution linear optical encoder. The optimum PID gains are derived using relay tuning method. In the laboratory, we have conducted several experiments to test the performance of the prototype soft actuator as well as the controller. We could achieve 5.73- and 10.15-nm RMS position errors in the steady state as well as tracking with a constant speed of 350 nm/s, respectively. We also present the outcome of various performance tests carried out when off-loader is in action as well as the actuator is subjected to dynamic wind loading.

Original languageEnglish
Article number014005
JournalJournal of Astronomical Telescopes, Instruments, and Systems
Volume4
Issue number1
DOIs
Publication statusPublished - 01-01-2018

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segmented mirrors
Telescopes
Mirrors
Actuators
actuators
prototypes
telescopes
astrophysics
vibration
controllers
gravity
sensor
disturbance
Controllers
mirrors
experiment
temperature
Derivatives
test
position errors

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Control and Systems Engineering
  • Instrumentation
  • Astronomy and Astrophysics
  • Mechanical Engineering
  • Space and Planetary Science

Cite this

Deshmukh, Prasanna Gajanan ; Mandal, Amaresh ; Parihar, Padmakar S. ; Nayak, Dayananda ; Mishra, Deepta Sundar. / Design, development, and validation of a segment support actuator for the prototype segmented mirror telescope. In: Journal of Astronomical Telescopes, Instruments, and Systems. 2018 ; Vol. 4, No. 1.
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Design, development, and validation of a segment support actuator for the prototype segmented mirror telescope. / Deshmukh, Prasanna Gajanan; Mandal, Amaresh; Parihar, Padmakar S.; Nayak, Dayananda; Mishra, Deepta Sundar.

In: Journal of Astronomical Telescopes, Instruments, and Systems, Vol. 4, No. 1, 014005, 01.01.2018.

Research output: Contribution to journalArticle

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