带挠性帆板的太阳同步轨道卫星的姿态动力学模型

本文研究一颗带固定的对称挠性帆板的太阳同步极轨道三轴稳定卫星的姿态动力学问题。首先给出考虑太阳帆板挠性影响时,卫星姿态动力学方程的一般形式。然后,在计入太阳帆板弯曲振动和扭转振动的情况下,导出了经线性化处理后的姿态动力学模型,并给出了所忽略的非线性项的计算公式。最后得到便于分析和设计卫星姿态控制系统的解耦形式的无量纲姿态动力学方程。     

空间停靠动力学和控制

本文研究空间停靠是广义的，它包括停留和靠近两个内容。本文首先研究空间靠近动力学方程；其次讨论保持点的动力学特性和保持点轨迹稳定的必要条件；最后介绍靠近段安全可靠的控制策略，其中包括主动稳定保持点轨迹的控制方案。     

挠性航天器伸展动力学分析

本文导出了带挠性伸展附件航天器姿态动力学方程，研究了附件伸展和振动对姿态动力学的影响。对于附件按指数规律伸展情况，以及附件长度的次方随时间线性变化情况，给出了姿态角速率的渐近公式。     

旋转充液系统全飞行过程非线性动力学仿真

本文考虑一类刚认耦合的旋转充液系统的飞行动力学问题，在依据力学变分原理给出基本方程，导出全飞行过程运动状态方程的基础上，建立了相应的仿真模型。可能通过对Navier-Stokes方程求解和液体流动的惯性波振动特性，给出液体的反作用力矩。经过仿真实验，分析角运动的时间序列，给出了比较详尽的飞行不稳定机制分析结果。     

一类椭圆轨道交会中的动力学方程研究

研究了一类追踪器和目标器轨道半长轴相差不大、轨道面外的距离相差不大的小偏心率椭圆交会的动力学问题.首先选择合适的圆轨道上的点建立参考系,推导出针对圆轨道参考系的无量纲化线性定常方程,并获得相应的相对状态;接着讨论该方程在小偏心椭圆轨道两冲量交会中的应用;最后进行数值仿真,验证动力学方程和制导策略,并与CW方程及制导策略的相关仿真进行比较.仿真结果表明本文给出的动力学方程的精度优于CW方程,能有效解决这类椭圆交会问题.     

某卫星挠性附件姿态动力学研究

根据导出的某有大型太阳帆板的挠性卫星数学模型,分析了模型中挠性振动对质心和姿态运动的影响,给出了卫星系统的动力学方程,并对帆板展开、卫星稳态运行的模型作工程化处理。分析和仿真结果表明：该方法能降低模型的复杂度,满足大型卫星的姿态指向精度和稳定度要求。     

大型空间运动体的建模

本文建立了大型空间运动体的模态方程,并利用模态方程导出传递函数矩阵,给出离散传递函数矩阵的分解形式。利用这种方法对控制系统进行设计和频域分析。     

非质心特征点相对位置和姿态估计方法研究

卫星编队飞行中,从星星体上偏离质心的任意特征点,其相对位置和相对姿态运动耦合。本文针对任意点的相对状态估计问题,推导了耦合相对轨道动力学方程和无陀螺相对姿态动力学方程,并且基于PSD敏感器对主星上点光源的视线测量值,提出了基于特征点耦合动力学和质心传统动力学的两种相对状态估计策略。针对每种策略分别设计了EKF和UKF两种滤波算法对相对状态进行估计。最后通过数学仿真对算法的有效性进行了验证,并对其计算量进行了分析。结果表明,四种算法均能对特征点的相对状态进行较高精度的估计。     

基于自适应控制方法的自主编队构型保持

对受未知干扰的低轨卫星编队构型保持进行了研究.由完整的非线性星间相对运动动力学方程给出用于控制器设计和稳定性分析的跟踪期望编队构型的误差方程,基于Lyapunov稳定性分析推导了干扰估计律,综合干扰估计律、反馈线性化和最优线性二次型控制器设计了自适应控制器,并证明了该自适应控制方法可保证对期望构型跟踪误差的全局渐近收敛.仿真结果表明:该自适应控制器可实现精确的构型保持,同时完成对未知干扰的估计.     

航天器内部液体晃动对交会对接动力学与控制的影响

本文从力学变分原理出发,建立了交会对接过程中追踪飞行器与目标飞行器的动力学方程,导出了两个飞行器之间的相对运动方程。以此为基础,讨论了最后逼近阶段的平移过程中,追踪飞行器内部液体的晃动规律,并进一步对飞行器之间的相对运动做了定性分析,论述了液体的晃动对交会对接相对运动中的动力学与控制的影响。     

三角平动点附近高阶解在轨道位置保持中的应用

首先给出三角平动点附近的高阶解析解,并计算了三种特殊的运动类型。以日–地+月系三角平动点附近无长周期运动分量的拟周期轨道作为目标轨道,探讨轨道保持问题。针对三角平动点任务的轨道保持问题,我们研究了两种轨道保持策略,分别为多点打靶轨道保持与重构目标轨道的策略。计算中,将轨道控制问题转化为非线性规划问题,并以优化方法求解。仿真表明优化方法在轨道保持问题求解方面非常有效。     

Development status and application of the electric propulsion system RIT-10 used for station-keeping

The German 10 mN high frequency ion thruster system RIT-10 designed at Giessen University, constructed at MBB, and tested essentially at DFVLR, has attained an engineering model status and stands shortly before qualification for space flight. First application is planned for RIT-10 as a north-south stationkeeping system in TV-Sat preoperational version where it is flown as an experiment in order to acquire experience for subsequent operational communication satellite missions. The paper first describes the existing hardware, then shortly discusses application aspects, the respective test program, and preflight and flight procedures considered to guarantee safe and efficient operation in space.     

Earth–Moon libration point orbit stationkeeping: Theory,modeling, and operations

Collinear Earth–Moon libration points have emerged as locations with immediate applications. These libration point orbits are inherently unstable and must be maintained regularly which constrains operations and maneuver locations. Stationkeeping is challenging due to relatively short time scales for divergence, effects of large orbital eccentricity of the secondary body, and third-body perturbations. Using the Acceleration Reconnection and Turbulence and Electrodynamics of the Moon's Interaction with the Sun (ARTEMIS) mission orbit as a platform, the fundamental behavior of the trajectories is explored using Poincaré maps in the circular restricted three-body problem. Operational stationkeeping results obtained using the Optimal Continuation Strategy are presented and compared to orbit stability information generated from mode analysis based in dynamical systems theory.     

Analysis and implementation of in-plane stationkeeping of continuously perturbed Walker constellations

The stationkeeping of symmetric Walker constellations is analyzed by considering the perturbations arising from a high order and degree Earth gravity field and the solar radiation pressure. These perturbations act differently on each group of spacecraft flying in a given orbital plane, causing a differential drift effect that would disrupt the initial symmetry of the constellation. The analysis is based on the consideration of a fictitious set of rotating reference frames that move with the spacecraft in the mean sense, but drift at a rate equal to the average drift rate experienced by all the vehicles over an extended period. The frames are also allowed to experience the J₂-precession such that each vehicle is allowed to drift in 3D relative to its frame. A two-impulse rendezvous maneuver is then constructed to bring each vehicle to the center of its frame as soon as a given tolerance deadband is about to be violated. This paper illustrates the computations associated with the stationkeeping of a generic Walker constellation by maneuvering each leading spacecraft within an orbit plane and calculating the associated velocity changes required for controlling the in-plane motions in an exacting sense, at least for the first series of maneuvers. The analysis can be easily extended to lower flying constellations, which experience additional perturbations due to drag.     

Thermodynamics and dynamics of pure interfaces

The paper derives, on a coherent postulatory basis, the basic set of equations needed to completely describe the thermodynamics and dynamics of pure interfaces. This set comprises: the equilibrium constitutive equation giving the surface tension as a function of the absolute temperature; the interface balance equations for momentum and internal energy; the non-equilibrium constitutive equations giving the surface transport coefficients (two viscosity coefficients and a thermal conductivity coefficient) as function of the absolute temperature. A discussion of the interface balance equations considered as boundary conditions for the field equations pertaining to the adjoining bulk phases is given and the inadequacies of previous ad hoc formulations pointed out.     

翼伞系统两体相对运动分析

为提高翼伞系统的测量和控制精度 ,分析物体和伞体之间的相对运动关系是十分必要的。在物 -伞之间两点吊挂及相应约束的条件下 ,分析了两刚体间的力学关系 ,建立了八自由度的两体相对运动模型。对运动的非线性偏微分方程组进行了数值求解 ,分析了单侧、双侧控制输入 ,及侧向突风干扰下的系统响应情况。算例分析的结果表明 ,此模型可用于分析和解释翼伞系统两体相对运动中的问题和现象     

Analysis and implementation of in-plane stationkeeping of continuously perturbed Walker constellations

The stationkeeping of symmetric Walker constellations is analyzed by considering the perturbations arising from a high order and degree Earth gravity field and the solar radiation pressure. These perturbations act differently on each group of spacecraft flying in a given orbital plane, causing a differential drift effect that would disrupt the initial symmetry of the constellation. The analysis is based on the consideration of a fictitious set of rotating reference frames that move with the spacecraft in the mean sense, but drift at a rate equal to the average drift rate experienced by all the vehicles over an extended period. The frames are also allowed to experience the $J_2$-precession such that each vehicle is allowed to drift in 3D relative to its frame. A two-impulse rendezvous maneuver is then constructed to bring each vehicle to the center of its frame as soon as a given tolerance deadband is about to be violated. This paper illustrates the computations associated with the stationkeeping of a generic Walker constellation by maneuvering each leading spacecraft within an orbit plane and calculating the associated velocity changes required for controlling the in-plane motions in an exacting sense, at least for the first series of maneuvers. The analysis can be easily extended to lower flying constellations, which experience additional perturbations due to drag.