Under the growing threat of space debris proliferation, researchers have long been seeking effective solutions to address the increasingly severe challenges posed by defunct satellites. Servicing spacecraft equipped with flexible rods have emerged as a promising approach for on-orbit detumbling malfunctioning satellites that act as debris, before their capture by a robotic arm in order to remove it from the working orbits. Yet the contact-induced vibrations and severe disturbances bring critical challenges to safe and efficient operations. While numerous studies have explored vibration suppression and control methods for detumbling systems, the integration of active variable stiffness (AVS) with nonlinear energy sink (NES) technologies to simultaneously mitigate vibrations and ensure robust detumbling control remains underexplored, despite its potential to revolutionize on-orbit servicing capabilities.
Recently, a team led by Xiaokui Yue from Northwestern Polytechnical University, China, unveiled a novel solution combining an NES-AVS device with a composite prescribed performance controller. The research, published in the Chinese Journal of Aeronautics, not only addresses the vibration challenges in flexible rod operations but also demonstrates enhanced efficiency during the detumbling processes.
The team published their work in Chinese Journal of Aeronautics on May 9, 2025.
"The key challenge lies in the dual problem of suppressing flexible rod vibration and maintaining control accuracy,"said Honghua Dai, a professor specializing in aerospace dynamics and control."We designed an NES-AVS device that adapts its stiffness in real-time using a piezoelectric actuator, while the composite controller ensures both transient and steady-state performance constraints."
The NES-AVS device integrates a cubic stiffness element with an AVS mechanism, where a small steel plate's buckling effect generates negative stiffness adjusted by the actuator. This design enables rapid vibration attenuation: simulations show the NES-AVS reduces flexible rod tip displacement by 84% within 15 seconds, outperforming conventional NES systems by 35%. Meanwhile, the composite controller, based on fast non-singular terminal sliding mode control (NSTSMC), incorporates a performance function to constraint tracking errors and an adaptive law to reject disturbance. For high velocity satellite with initial angular velocity of 12°/s, the controller achieves detumbling to below 3°/s within 450 seconds.
"Our approach integrates vibration suppression techniques with advanced control theory,"explained by Prof. Dai. "The NES-AVS dynamically adapts to vibration frequencies, while the controller ensures finite-time convergence even under actuator saturation that is a critical factor for real space operations."
The study also highlights the devices energy dissipation efficiency: the NES-AVS absorbs mechanical energy 1.8 times faster than traditional NES, as validated through comparisons of kinetic and potential energy decay rates. Additionally, the controller demonstrates superior robustness against contact-induced disturbance, with adaptive estimation of disturbance bounds enabling stable operation in both low-velocity and high-velocity detumbling scenarios.
However, Prof. Dai highlighted that further research is needed to optimize the NES-AVS for long-term space missions. "Future work will focus on enhancing resistance to space environmental factors like radiations and debris, as well as improving suppression efficiency for extended operations,"he said.
Other contributors include Hongwei Wang from the School of Astronautics at Northwestern Polytechnical University in Xi'an, China.
Original Source
Hongwei Wang, Honghua Dai, Xiaokui Yue. Vibration suppression and composite prescribed performance detumbling control for a tumbling satellite [J]. Chinese Journal of Aeronautics, 2025, https://doi.org/10.1016/j.cja.2025.103570.
About Chinese Journal of Aeronautics
Chinese Journal of Aeronautics (CJA) is an open access, peer-reviewed international journal covering all aspects of aerospace engineering, monthly published by Elsevier. The Journal reports the scientific and technological achievements and frontiers in aeronautic engineering and astronautic engineering, in both theory and practice. CJA is indexed in SCI (IF = 5.7, Q1), EI, IAA, AJ, CSA, Scopus.
