Testing of a 15-positioner module based on the MPS design for stage-5 telescopes

Assessing the performance metrics of theta-phi micro-robotic positioners is a key step toward understanding their operational behavior and ensuring that they meet the specifications of Stage-5 astronomical facilities, including the Chinese MUST, the American Spec-S5, and the European WST. A detailed examination of these metrics enables a clear evaluation of the system’s current capabilities while also revealing aspects that require further refinement, which in turn guides improvements in design and manufacturing. In this work, carried out in collaboration with Micro Precision Systems (MPS) in Switzerland, we present the results of positioning performance and angular tilt characterization conducted on a 6.2-mm-pitch robotic positioner module developed for high-density fiber placement in next-generation spectroscopic instruments. The prototype unit evaluated in this study was produced by MPS. The measured metrics, including positioning repeatability, datum repeatability, backlash, non-linearity, and angular tilt, are compared directly with the nominal performance targets defined for Stage-5 telescope systems.