A novel active vibration suppression approach based on a flywheel actuator for flexible spacecraft during attitude maneuvering is proposed in this paper. The flywheel is regarded as the only actuator. The rotation of the flywheel, the motion of the rigid body, and the vibration of the modes are coupled in this paper. The system model is obtained using the Euler-Lagrange methodology and the Assumedmode Method, in which the dynamics of the flywheel is considered. The stability of the flywheel transfer function from input voltage to output torque is analyzed using the Lyapunov method. Effects on system caused by flywheel are analyzed. Based on component synthesis vibration suppression theory, a typical vibration suppress law during attitude maneuver is derived. The input voltage of the flywheel actuator is designed according to this law. The presented novel approach is easily applied and practical without changing the spacecraft's structure properties. The simulation results and experiments on an air bearing spacecraft simulator are presented to verify the efficacy of the proposed approach.

The maintenance of the nominal multirevolution elliptic halo orbit, whose special features can benefit mercurial explorations, is first investigated through Monte-Carlo simulations in the elliptic Sun-Mercury model, and then validated in the high-fidelity ephemeris model. The receding horizon control strategy solved by the indirect Radau pseudospectral method demonstrates that the orbit can be maintained robustly with respect to very large initial deviations. Moreover, the result proves that the elliptic Sun-Mercury model is an accurate approximation.

针对柔性航天器挠性附件振动与姿态机动耦合降低控制精度的问题，给出了一种混合分力合成主动振动控制方法，给出了若干定理并进行了理论证明。其次，系统参数波动及随机干扰因素不可忽略，对经典滑模控制器进行优化，形成一种新型自适应-滑模变结构控制器。为应对控制力矩抖振和系统参数鲁棒性差等缺点，引入新型滑模边界层和力矩更新率。最后，提出了将混合分力合成方法与姿态控制相结合的策略。借助压电智能材料实现两者的联合应用。仿真结果表明，改进的滑模变结构控制器可有效降低参数变动及外干扰影响，结合混合分力合成方法后，柔性附件残余振动得到了明显的控制，进一步提高了姿态精度

Periodic disturbance may cause serious effects on the attitude of meteorological satellites, and the attenuation of periodic disturbance is required. In this paper, a fundamental study on the optimal design of constant compensations against known-law periodic disturbance for meteorological satellites is investigated. An analytical solution for the relationship between the frequency and amplitude ratios and the response of a typical second-order vibration system is firstly derived. The compensation and disturbance torques are determined according to practical engineering. The criteria for designing the optimal compensations are based on the analytical and simulation results. Then, the criteria are applied to a flexible spacecraft actuated by constant control torque in the presence of sustained periodic disturbance. The optimal compensation torque parameters for spacecraft are acquired based on former criteria. The compensate effectiveness of the optimal compensation torque is provided and compared with results of other selections in the frequency and amplitude ratio domain. Numerical simulation results and experimental results clearly demonstrate the good performance of proposed criteria. This work provides a significant reference for the vibration attenuation of meteorological satellites in the present of periodic disturbance.