From research to industry: Development of a high-resolution measurement system for mirrored heliostats in series production

A new measurement system able to measure the shape accuracy of complete mirrored heliostat modules in series production was developed. The applied deflectometry measurement method is based on the reflection of regular patterns in the mirror surface and their distortions due to mirror surface deviations. The measurement system’s key features are its high spatial resolution, its low global measurement uncertainty of less than 0.2 mrad and its total measurement and evaluation time of few minutes. The measurement process is contact-free and completely automatic, which allows a 100% optical quality control of the production of the heliostat modules for a typical solar tower power plant. The system is validated by measuring a flat reference surface and by comparison to manual photogrammetry measurements. This makes the new measurement system, called QDec-M-Helio, a valuable tool for final geometric quality control of heliostats in series production, especially for new generation heliostats which obtain its final curvature during a bonding process between mirror and support structure from a precise jig.