Precision control of miniature SCARA robots for multi-object spectrographs

Advances in astronomy led to the demand for measuring the spectra of multiple night sky objects simultaneously. Some of these Multi-Object Spectrographs use robotic systems that position optical fibers in the focal plane of the observing telescope. These systems rely on precise fiber placement in order to collect the light spectra of faint stars and galaxies. Here, we present how to design, control, and operate micro SCARA-like robots to position optical fibers to micrometer precision. As an illustrative example, we show the design and performance results of the SDSS-V fiber positioner, which has been build for the Apache Point Observatory and the Las Campanas Observatory with 500 units for each telescope.