电动帆航天器姿态动力学与控制研究

项目名称： 电动帆航天器姿态动力学与控制研究

项目编号： No.11502018

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 胡权

作者单位： 北京理工大学

项目金额： 22万元

中文摘要： 电动帆是一种新兴的不消耗工质的推进方式，其通过建立巨大的正电势电场改变太阳风中正电荷粒子的运动方向，从而与太阳风发生动量交换，获得推力。电动帆的主要组件是约100根15~20km长的绕中心体均匀分布的高电势导线，导线端部带有辅助导线用于姿态控制，整个系统通过自旋维持展开，属于典型的大尺度柔性多体系统。电动帆能够实现低成本的航天任务，目前已有众多基于电动帆的轨道设计；但是鲜见系统姿态动力学和控制研究，该问题涉及到多个理论和技术难点：电动帆导线易发生大范围变形、与太阳风通过库仑力耦合，系统释放展开过程复杂，自旋速率与自旋面方向存在耦合，导线数量众多且作用机理复杂。针对以上问题，本项目将分别研究：单根高电势导线在太阳风环境中的动力学建模；电动帆展开过程精细建模与分析；电动帆等效简化模型；分别设计系统自旋控制律，导线电势操纵律。本研究将完善现有电动帆理论，也将丰富多体系统动力学和控制领域的成果。

中文关键词： 电动帆；多体系统动力学；库仑力；自旋稳定；姿态控制

英文摘要： An electric sail is an innovative propulsion concept that uses the ambient solar wind momentum for spacecraft thrust. The momentum exchange between the electric sail and the solar wind is achieved by establishing a huge positive electric filed around the spacecraft, and repelling the particles with positive charge, thus the thrust is extracted from the solar wind. The major component of an electric sail is a number (on the order of 100) of long conducting main tethers. They are connected to a solar-powered election gun for which the aim is to maintain the tethers at a high (up to 20kV) positive potential. On the tips of the main tethers, auxiliary terms are attached for the attitude control. The whole system is spinning around an axis to deploy and stretch the tethers. It can be viewed as a typical multibody system. The electric sail has infinite specific impulse and an ultralow mass. It is rather suitable for interstellar flight. There have been many studies about the orbit design of the electric sail, but few studies focus on its attitude dynamics and control issue, which involves many difficult theoretical and technical problems: the tethers of the electric sail are prone to have large deformation and coupled with the solar wind through Coulomb forces; the deployment of the sail is rather complicated; the spin rate and the spin direction of the electric sail are also coupled; the number of the actuators (the auxiliary tethers) for the attitude control is enormous, which makes the steering law design difficult. To settle the above problems, this study will focus on: dynamic modeling of a single tether with high positive potential in the solar wind; the detailed dynamics of the deployment of the electric sail; the equivalent simplified model of the system; design the control law for the system spin motion; designing the steering law of the controllable potential on the tethers for the attitude control. This study will complete the theory of the electric sail, and provide the foundations for the practical applications of the electric sail, moreover, the developed theories and methods will further enrich the theories of dynamics and control of multibody systems.

英文关键词： Electric sails;Multibody dynamics ;Coulomb force;Spin stabilization;Attitude control