Nowadays, most spacecraft use solar array continuously facing the sun by solar array drive assembly (SADA) to increase the energy efficiency. However, in spacecraft with rotating flexible appendages, system dynamics and control are very difficult.
There has been an extensive study on suppressing the vibration caused by flexible appendages in such spacecraft across the world. What is attracting a great deal of attention is a method by the robust controller design. However, almost all robust control systems considered only fixed flexible appendages and neglected their rotation dynamics.
Sonu Kwang, a post-graduate student at the Faculty of Aerospace Engineering, proposed an attitude control method to suppress the vibration of flexible spacecraft with rotating solar array.
First, he simplified the singular dynamic model of spacecraft with rotation of flexible appendages by introducing extended state and modal identities into a non-singular state space-formed dynamic model. Based on this simplified dynamic model, he developed a PD-type static output feedback controller that essentially guarantees asymptotic stability and disturbance rejection. Then, he designed a compensator for the extended system including a static output feedback controller in order to ensure the stability of the control system under the influence of rotations of solar array, variation of natural frequency and damping coefficients, high-order flexible modes and measurement noises.
Through computer simulations, he found that the proposed attitude control system with and without compensators stabilized the attitude within 60s and suppressed flexible vibration.
You can find the details in his paper “Vibration Suppression for Flexible Spacecraft with Rotating Solar Array” in “Proceedings of KUTIC-2025”.