Malfunctioning satellites that behave as uncontrolled debris present significant hazards. Traditional servicing spacecraft using flexible rods face major obstacles, particularly vibration and control instability during detumbling and capture. Addressing this, the research team led by Xiaokui Yue proposed a new system that not only damps vibrations swiftly but also maintains precise control under space disturbances.
"The key challenge lies in the dual problem of suppressing flexible rod vibration and maintaining control accuracy," said aerospace dynamics professor Honghua Dai. "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."
This NES-AVS mechanism employs a cubic stiffness element and a buckling steel plate to generate adjustable negative stiffness. It enables rapid vibration attenuation, reducing flexible rod tip displacement by 84% within 15 seconds-an improvement of 35% over traditional NES devices. Meanwhile, their composite controller leverages fast non-singular terminal sliding mode control to manage tracking errors and reject disturbances.
For satellites with high initial angular velocity (12 /s), the system reduced spin to under 3 /s in 450 seconds. Prof. Dai noted, "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."
Simulation results also confirmed that the NES-AVS device dissipates energy 1.8 times faster than conventional NES systems. The control strategy demonstrated robust performance across different detumbling scenarios, aided by adaptive disturbance estimation.
Looking ahead, Dai emphasized the need to further refine the system for long-term missions in harsh space environments. "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.
The research team also includes Hongwei Wang of the School of Astronautics at Northwestern Polytechnical University in Xi'an, China.
Research Report:Vibration suppression and composite prescribed performance detumbling control for a tumbling satellite
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Northwestern Polytechnical University
Space Technology News - Applications and Research
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