Attitude-Vibration Composite Control of the Large Membrane Sail Satellite During Deorbiting

The membrane drag sail, as an active deorbit device, can alleviate the space debris problems. The increasing size of spacecraft leads to a requirement of larger sail, so as to improve deorbit efficiency. This requirement amplifies the flexible properties of the membrane sail and the influence of attitude on the windward area. Furthermore, the physical environment changes continuously as the orbit altitude decreases. This leads to the variation of attitude and the flexible vibration. Therefore, the deorbit phase is a complex dynamic process in which the orbit, attitude, and vibration are coupled with each other. In the existing research, most attitude control and vibration suppression are conducted separately, neglecting their mutual coupling effects and the orbit dynamics coupling effect, thereby compromising control accuracy. To address the challenge, this paper first establishes an orbit–attitude–vibration coupled dynamics model for a large-scale membrane sail deorbit system within the dual quaternion framework using the Kane equation. Subsequently, a nonlinear model predictive control (NMPC) strategy for integrated attitude-vibration control is developed. Based on the coupled dynamics model, the predictive model is constructed that treats attitude and vibration parameters as unified state variables. Optimal control sequences are formulated by solving a nonlinear optimization problem with a tracking-error-based objective function. Then at each subsequent timestep, the updated desired values and system states are fed into the optimizer to resolve the problem, achieving receding horizon optimization (RHO). Finally, a deorbit control simulation is conducted. The results show that the established dynamics model could describe the coupling between the orbit, attitude and vibration dynamics. In addition, with the control method implemented, the system can continuously track the attitude with the largest windward area, maintaining single-axis attitude angle error within, while sustaining flexible deformation below 1% of the characteristic dimension. In summary, this paper offers an integrated attitude-vibration control strategy considering orbital dynamics coupling, which improves the deorbit efficiency and stability of the large membrane sail system in the deorbit phase.