Solar Sailing: Attitude, Orbit, and Shape Control

太阳航行：姿态、轨道和形状控制

• 批准号: RGPIN-2020-04037
• 负责人: Damaren, Christopher
• 金额: $ 2.84万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=743275
• 关键词: Solar; Sailing; Attitude; Orbit; Shape

Spacecraft exhibit three distinct types of motion. The evolution of their position in space is the subject of orbital dynamics. The evolution of their orientation with respect to some reference, such as the Earth, is described by attitude dynamics. Larger spacecraft can be  quite flexible and one is concerned with their structural dynamics which describes vibrational and wrinkling types of behaviour. Controlling these three types of motion typically requires feedback control systems which use sensors to monitor the spacecraft motion and then correct errors using appropriate actuators which produce forces and torques. Forces are required to control orbits whereas torques are needed to control orientation (also called attitude). In some problems, the spacecraft's attitude can have a large effect on its orbit. An interesting example is a solar sail, which is a large, flimsy gossamer structure which acts a mirror to reflect the solar radiation acting upon it. This produces a reaction force on the sail. Controlling solar sails is a challenging application because the orbital dynamics, attitude dynamics, and structural dynamics are highly coupled. The orbital path and the orientation of the sail are coupled because the forces stemming from radiation pressure act in a direction that depends on the sail attitude. This is analogous to the motion of a sailboat moving on the surface of a lake in wind. A useful destination for a solar sail is a point between the Sun and the Earth where the solar sail can be used to detect solar storms and communicate a warning to the Earth before the storm arrives. Another useful point to place a solar sail is in a "pole-sitter" position whereby the sail does not orbit the Earth but rather sits above the North Pole and moves with the Earth as it moves around the Sun. In order to use these special orbits, one needs to develop steering strategies to achieve them. We would like to determine attitude motions to reach these places in the shortest time possible. Given the solution of the previous problem, we would like to determine control approaches to follow a prescribed attitude motion. Two actuation approaches will be studied: the use of tip vanes (little miniature solar sails gimballed to the corners of the main sail) and the use of balance masses. The key problem that needs to be solved initially is the determination of the actuator motion required to provide the control torques required by the control system. Having handled the coupled attitude-orbit control problem, the next problem in the hierarchy to be studied brings shape control into play. There are two subproblems to be considered: vibration suppression and wrinkle prevention. Both are complicated by the lack of distributed actuation and sensing and the fact that the actuation is physically noncollocated with the typical sensing which one assumes would include the attitude and angular rate information measured at the centre of the sail.

航天器表现出三种不同类型的运动。它们在太空中的位置的演变是轨道动力学的主题。它们相对于某些参考（例如地球）的方向的演变是通过态度动力学来描述的。较大的航天器可以非常灵活，并且与它们的结构动力学有关，该动力学描述了振动和包裹的行为类型。控制这三种类型的运动通常需要反馈控制系统，这些反馈控制系统使用传感器来监视航天器运动，然后使用适当的执行器纠正错误，从而纠正误差。需要力才能控制轨道，而需要扭矩来控制方向（也称为尝试）。在某些问题中，航天器的尝试可能会对其轨道产生很大的影响。一个有趣的例子是太阳帆，这是一个庞大的脆弱的散布结构，其作用镜子反映了太阳辐射的作用。这会在帆上产生反作用力。控制太阳帆是一个挑战应用程序，因为轨道动力学，态度动力学和结构动力学高度耦合。轨道路径和帆的方向是耦合的，因为辐射压力源自乘坐式态度的方向。这类似于帆船在风中移动在湖面上的运动。太阳帆的一个有用目的地是太阳与地球之间的一个点，在那里太阳帆可用于检测太阳风暴并在风暴到来之前向地球传达警告。放置太阳能航行的另一个有用的点是“杆子”位置，帆不会绕地球绕，而是坐在北极上方，并随着地球在太阳周围移动而与地球一起移动。为了使用这些特殊的轨道，需要制定转向策略以实现它们。我们想确定在最短的时间到达这些地方的态度动议。考虑到以前问题的解决方案，我们想确定控制方法以遵循规定的态度运动。将研究两种动作方法：使用尖端叶片（小小的太阳帆都戴在主帆的角落）和平衡质量的使用。最初需要解决的关键问题是确定提供控制系统所需的控制扭矩所需的执行器运动。处理了耦合的态度 - 轨控制问题后，要研究的层次结构中的下一个问题将形状控制带入游戏中。有两个子问题要考虑：振动抑制和预防。由于缺乏分布式动作和敏感性以及该动作在典型的敏感性上进行物理收缩的事实，这两者都变得复杂，人们认为这将包括在帆的中心测量的态度和角度率信息。