Communications in Nonlinear Science and Numerical Simulation ( IF 3.9 ) Pub Date : 2020-12-13 , DOI: 10.1016/j.cnsns.2020.105663 Chonggang Du , Zheng H. Zhu , Gangqiang Li
This paper investigates the modelling of rigid-flexible coupling effect on the attitude dynamics and spin control of an electric solar wind sail (E-sail) by developing a rigid-flexible coupling dynamic model. The model considers the attitude dynamics of the central spacecraft, the elastic deformation of the tethers and the rigid-flexible coupling between the spacecraft and the tether. The attitude and translation dynamics of the central spacecraft is described by the natural coordinate formulation, while the tether deformation is described by the high-fidelity nodal position finite element method. The latter enables a natural coupling between the motion of the flexible tethers and the rigid-body dynamics of the central spacecraft at the anchor points where the tethers connected to the spacecraft by Lagrange multipliers. Based on the model, the influence of the rigid-flexible coupling, E-sail orientation and geometrical configuration on the dynamic characteristics of the E-sail is investigated by a parametric analysis. It is found that the deformation motion of flexible tethers will cause the offset of centres of mass and thrust of E-sail, which generates disturbance torques on the central spacecraft. Through the nonlinear rigid-flexible coupling, the disturbance causes the tension fluctuations and the undesired fluctuations of the E-sail's attitude and spin rate. The parametric analysis indicates that the E-sail is more stable if the spin plane passes the centre of mass of the central spacecraft. Finally, the controllability of E-sail spin rate is investigated by applying simple feedback torque controls at the central spacecraft or at the central spacecraft and the remote units simultaneously. The analysis demonstrates the spin rate cannot be controlled by the central spacecraft along due to the rigid-flexible coupling and must be controlled at the remote units with finite control input.
中文翻译:
刚柔耦合对电动太阳风帆姿态动力学的影响
通过建立刚柔耦合动力学模型,研究了刚柔耦合作用对电动太阳风帆(E-sail)姿态动力学和旋转控制的建模。该模型考虑了中央航天器的姿态动力学,系绳的弹性变形以及航天器与系绳之间的刚柔耦合。中心航天器的姿态和平移动力学由自然坐标公式描述,而系链变形则由高保真节点位置有限元方法描述。后者使得柔性系绳的运动与中央航天器在锚点的自然耦合成为可能,在锚点处系绳通过拉格朗日乘数连接到航天器。根据该模型,通过参数分析研究了刚柔耦合,电子风帆取向和几何构型对电子风帆动力特性的影响。发现挠性系绳的变形运动将引起重心和电子帆的推力偏移,从而在中央航天器上产生干扰扭矩。通过非线性的刚柔耦合,扰动会引起拉力波动以及电子帆的姿态和旋转速度的意外波动。参数分析表明,如果旋转平面经过中央航天器的质心,则电子风帆会更稳定。最后,通过在中央航天器上或同时在中央航天器和远程单元上应用简单的反馈转矩控制来研究电子帆旋转速度的可控性。分析表明,旋转速度由于刚性-挠性耦合而不能由中央航天器控制,而必须在具有有限控制输入的远程装置上进行控制。