Dynamic modeling of a cable-driven parallel robot with a Stewart platform for use in FAST

Five-hundred-meter aperture spherical radio telescope (FAST) uses a cable-driven parallel robot with a Stewart platform for precision positioning at the millimeter level. This paper presents a dynamic modeling method for this type of rigid-flexible mechanism which accurately models the cable and the Stewart platform and eliminates system vibrations by iterating the Newton-Euler equations of the intermediate structure between the two models. The nature of the coupled system vibrations is also analyzed to explain the impact of the Stewart platform's error compensation on the system motion with the error composition modeled numerically. This research will improve the FAST observation accuracy and provides a theoretical basis for control algorithms for this type of rigid-flexible mechanisms. © 2022 Press of Tsinghua University. All rights reserved.