Abstract:

A space flexible manipulator (SFM) is a key development for on-orbit operations, yet even low-speed motions trigger significant structural vibrations in complex space environments. This paper proposes a vibration control method based on stiffness modulation of a flexible manipulator. The SFM is modeled as a hub-beam system with variable stiffness, and two typical modulation forms are considered: single stiffness modulation and periodic stiffness modulation. Single stiffness modulation exhibits excellent vibration suppression performance, for which an approximate analytical solution for the optimal modulation is derived. For the periodic form, resonance-like behaviors are observed, and the relationship between the variable-stiffness parameters and the resonance behaviors is identified. A Floquet-based stability analysis is adopted to theoretically determine the parametric resonance frequencies, revealing the underlying mechanism governing the observed resonance phenomena. Furthermore, the optimal periodic stiffness modulation that suppresses vibrations by avoiding resonance regions is presented. This study offers valuable insights into the design of SFMs with variable stiffness for effective vibration suppression.

Key words: space flexible manipulator (SFM), vibration suppression, stiffness modulation, stability analysis