空间网状天线展开动力学的多尺度建模及非线性动力学研究

Mesh reflectors have predominated antennas in high-resolution satellites, benefited from their high gains, high package ratios and low areal densities. Besides mesh, a reflector mainly contains a foldable rib or truss. It is in charge of unfolding the mesh from the stowed configuration to the working configuration by preloaded passive springs and/or active motors. The deployment dynamics is of great concern because any failure may result in an immediate fatal error of the valuable satellite. A flexible multibody simulation is supposed to be a promising method for studying the deployment dynamic, especially encouraged by the great progress achieved on modeling individual flexible bodies in the past decades. Nevertheless, fulfilling a full-scale deployment simulation of a large antenna remains an extremely challenging task. In our opinion, the bottleneck problem is the inherent multiscale nature of the deployment dynamics coming from both length-scale and time-scale. These multiscale problems involve fine finite element mesh and small numerical integration time step in simulation, resulting in low calculation efficiency. Moreover, recent research has highlighted that the demanded force of unfolding mesh antenna is nonlinear, exhibiting negative stiffness, while a conventional linear spring owns positive stiffness. To tackle the above conflictions, we plan to conduct the following research: (1) Propose a novel modeling method to deal with the multiscale problems in the unfolding process. (2) Build a full-scale model of mesh antenna, and study the underlining deployment dynamics thoroughly and systematically. (2) Develop a kind of passive actuators with negative stiffness to meet the particular demand of unfolding mesh antenna. These studies can directly guide design of deployable mesh reflectors in China. The achieved nonlinear actuator with negative stiffness can also be applied in other fields, such as vibration reduction. Besides, the developed multiscale modeling method is potential to be applied to other applications, such as arresting gear systems and to remarkably extend the ability of multibody simulation in solving complex engineering problems.

大型网状可展天线是高分辨率对地观测卫星的核心部件，入轨后能否在储能弹簧和/或电机的驱动下成功展开直接关系到卫星任务的成败，故此，借助仿真深入理解展开动力学行为并做出适应其动力学特性的设计至关重要。近年来，虽然多体理论在柔体建模方面已获突破，但仿真全尺寸天线展开仍是一个难以完成的任务，其瓶颈是系统内在的多尺度本质导致的计算效率低下。此外，近期研究指出天线展开动力需求是非线性的，呈负刚度，而普通弹簧刚度为正。为解决以上问题，本课题拟开展如下工作：(1)发展网状天线的多尺度建模方法，大幅提高全尺寸模型的计算效率；(2)建立网状天线全尺寸仿真模型，深入研究展开动力学行为；(3)研发负刚度驱动器以匹配天线展开力需求。项目成果可为天线提供设计指导和实物支撑。研发的负刚度驱动器可应用于其他领域，如减振；发展的多尺度建模方法可推广至其他多体系统中，如舰载机拦阻索，进一步拓展柔性多体解决实际工程问题的能力。

大型网状可展天线是高分辨率对地观测卫星的核心部件，入轨后能否在储能弹簧和/或电.机的驱动下成功展开直接关系到卫星任务的成败，故此，借助仿真深入理解展开动力学行为并做出适应其动力学特性的设计至关重要。近年来，虽然多体理论在柔体建模方面已获突破，但仿真全尺寸天线展开仍是一个难以完成的任务，其瓶颈是系统内在的多尺度本质导致的计算效率低下。此外，近期研究指出天线展开动力需求是非线性的，呈负刚度，而普通弹簧刚度为正。为解决以上问题，本课题主要完成了如下三项研究工作：(1)发展网状天线的多尺度建模方法，大幅提高全尺寸模型的计算效率；(2)建立网状天线全尺寸仿真模型，深入研究展开动力学行为；(3)研发负刚度驱动器以匹配天线展开力需求。仿真方面的工作已用于预测我国可展环型网面天线的在轨展开动力学行为；此外，研发的负刚度驱动器目前已完成两次专利转化，拟用于下一代天线的展开驱动器中。项目成果既为天线设计提供仿真分析工具也为驱动组件提供实物支撑。研发的负刚度驱动器可应用于其他领域，如减振；发展的多尺度建模方法可推广至其他多体系统中，如舰载机拦阻索，进一步拓展柔性多体解决实际工程问题的能力。