一类带柔性附件充液航天器姿态机动控制

ATTITUDE REORIENTATION CONTROL FOR LIQUID-FILLED SPACECRAFT WITH ONE KIND OF APPENDAGE

基于Lyapunov稳定性理论研究了用动量轮控制一类带轻质悬臂梁附件的充液航天器的姿态机动控制问题,其中晃动液体用黏性力矩球摆模型代替,悬臂梁附件用若干集中质量代替.用动量矩定理和Lagrange方程分别推导得到航天器主刚体、等效球摆、等效集中质量的动力学方程,所用反馈控制律包含了与动量轮角加速度密切相关的权重因子,利用系统初、终状态和到达最终姿态所需时间解析确定此权重因子.同时利用Lyapunov稳定性理论得到了实现最终姿态机动的稳定性判据.数值仿真表明所用控制律的有效性,分析附件的相对主刚体平面的转角、相对系统质心的高度、长度、刚度、质量、阻尼系数和到达最终姿态所需时间等因素对控制过程中航天器剩余章动角的影响大小.

Attitude reorientation control by momentum transfer via Lyapunov stability theory for liquid- filled spacecraft with lightweight cantilever appendage is studied. The sloshing liquid is substituted by a viscous pendulum ball, and the cantilever appendage is substituted by several concentrated particMs. Dynamics equations of the major rigid body, the pendulum ball, and the concentrated 15articles are derived through the theorem of moment of momentum and Lagrange equation. The feedback control law used a weighting coefficient related nearly with the angular acceleration of the wheel, which can be determined by the initiM and final states of the system and the steady state time of attitude maneuver. A criterion guarantying to achieve attitude reorientation is attained by Lyapunov stability theorem. Numerical simulations indicate the validity of the control law. Sensitivity of residual nutation angle of the spacecraft is analyzed to the rotation angle of the appendage to the plaae of the major rigid body, the relative height of the appendage to the center of mass of the system, the length of the appendage, the rigidity of the appendage, the mass of the appendage, the vibration damping of the appendage and the steady state time of the attitude maneuver.