Performance characterization and control scheme derivation for "R-FLEX", flexure-based fiber positioner robot for Spec-S5 and future large-scale spectroscopic instruments
POSTER
Abstract
The ”R-FLEX” positioner robot is a miniature high-precision fiber robot design for Spec-S5, intended
to improve upon the already massively successful DESI two-stage rotation robots. In this paper, we
take diagnostics of the robot through some preliminary testing, gathering precision and accuracy data.
We find root-mean-squared error (RMSE) at around 5 microns in both random-move ’cruise speed’
tests and small-step ’creep speed’ tests in the posive φ direction, but higher RMSE in the negative
φ. We use this information to set up correction-move scripts, which work exceptionally well with
over 95% of robots within 5 microns error after one correction. Through this, we derive the optimal
control scheme to be used during a future ’lifetime test’, the test to investigate how the robot performs
through many times its realistic lifetime. This will replicate the likely move pattern of Spec-S5 robots
in operation, and will be informative on whether this design can be pursued further in the R&D process.
to improve upon the already massively successful DESI two-stage rotation robots. In this paper, we
take diagnostics of the robot through some preliminary testing, gathering precision and accuracy data.
We find root-mean-squared error (RMSE) at around 5 microns in both random-move ’cruise speed’
tests and small-step ’creep speed’ tests in the posive φ direction, but higher RMSE in the negative
φ. We use this information to set up correction-move scripts, which work exceptionally well with
over 95% of robots within 5 microns error after one correction. Through this, we derive the optimal
control scheme to be used during a future ’lifetime test’, the test to investigate how the robot performs
through many times its realistic lifetime. This will replicate the likely move pattern of Spec-S5 robots
in operation, and will be informative on whether this design can be pursued further in the R&D process.
*This work was supported in part by the US Department of Energy, Office of Science, Office of Workforce Developmentfor Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internship (SULI) program at Lawrence Berkeley National Lab.
Publication: Hope, A., Wenner, N., Silber, J., Schlegel, D. "R-FLEX: flexure-based
positioner robots for future massively parallel spectroscopic instruments" , In preparation
Presenters
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Andrew P Hope
- University of Michigan