Structural optimization and performance analysis of the cable-driven fine adjustment mechanism for the new FAST feed cabin.

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the world's largest and most sensitive single-dish radio telescope. To meet the growing demands of astronomical observations, the FAST team has proposed a new feed cabin configuration based on a cable-driven fine-tuning mechanism. This design replaces the traditional rigid A-B rotator and Stewart platform with a lightweight steel cable structure, significantly reducing the overall structural weight. To satisfy receiver installation requirements, enhance the payload capacity of the receiver platform, and maximize zenith angle coverage, this paper proposes a modeling approach tailored to the new configuration and conducts structural optimization under cable tension constraints. Simulation results demonstrate that the new configuration achieves a substantial improvement in payload capacity and extends the zenith angle to at least [Formula: see text], enabling FAST to accommodate a wider range of receivers and enhance sky coverage near the Galactic center. The proposed feed cabin design not only meets current scientific needs but also provides a robust technical foundation and feasible upgrade path for future expansion and array development of FAST.