Asymptotic study of a complete magnetic attitude control cycle providing a single-axis orientation

The angular motion of an axisymmetrical satellite equipped with the active magnetic attitude control system is examined. Attitude control system has to ensure necessary orientation of the axis of symmetry in the inertial space. It implements the following strategy: coarse reorientation of the axis of symmetry with nutation damping or “-Bdot” without initial detumbling; spinning-up about the axis of symmetry to achieve the property of a gyro; fine reorientation of the axis in the inertial space. Dynamics of the satellite is analytically studied using averaging technique on the complete control loop consisting of five algorithms. Solutions of the equations of motion are obtained in terms of quadratures for most cases or even in closed-form. The latter allowed to study the dependence of motion parameters including time-response with respect to the orbit inclination and other parameters for all algorithms.     

Study of a bunch of three algorithms for magnetic control of attitude and spin rate of a spin-stabilized satellite

We consider the angular motion of an axi-symmetrical satellite equipped with an active magnetic attitude control system. Dynamics of the satellite is studied on the entire control loop, consisting of a bunch of three successively used algorithms. The control cycle includes the stages of nutation damping, spinning up the satellite about its symmetry axis, and reorienting the symmetry axis into a preset direction in the inertial space. The results are confirmed by numerical simulations.     

Investigation of the effectiveness of an algorithm of active magnetic damping

We consider the rapid rotation of a satellite equipped with an active magnetic attitude control system with the -Bdot algorithm designed to damp the initial angular velocity. The time-response of the algorithm is analytically studied as a function of orbit inclination.     

A hybrid attitude controller consisting of electromagnetic torque rods and an active fluid ring

In this paper, a novel hybrid actuation system for satellite attitude stabilization is proposed along with its feasibility analysis. The system considered consists of two magnetic torque rods and one fluid ring to produce the control torque required in the direction in which magnetic torque rods cannot produce torque. A mathematical model of the system dynamics is derived first. Then a controller is developed to stabilize the attitude angles of a satellite equipped with the abovementioned set of actuators. The effect of failure of the fluid ring or a magnetic torque rod is examined as well. It is noted that the case of failure of the magnetic torque rod whose torque is along the pitch axis is the most critical, since the coupling between the roll or yaw motion and the pitch motion is quite weak. The simulation results show that the control system proposed is quite fault tolerant.     

Elimination of relative secular drift of orbits of two satellites caused by polar oblateness of the Earth

A method of elimination of relative secular drifts in satellite formations is suggested for the case of influence of a perturbation due to polar oblateness of the Earth. The method is applied to eliminate relative secular drifts in the case when a satellite is controlled using an engine mounted along its orientation axis (the satellite is supplied with a passive magnetic attitude control system) and with the help of a solar sail installed on one of the satellites. Analytical results are confirmed by numerical simulation.     

基于机器学习的卫星姿态控制律设计

传统的优化算法只能针对给定控制律的指定参数进行优化.机器学习的方法,不仅进化参数,而且可以按给定准则进化出卫星姿态控制律表达式.建立卫星姿态动力学模型及敏感器和执行机构的原理与误差模型,构成含噪声的单自由度的闭环数字仿真系统.统计一段时间内仿真结果的姿态精度和稳定度作为该控制律的适应度函数.针对姿态控制律选定合适的函数...     

多体卫星复合控制物理仿真试验系统

对于具有星间链路天线的多体卫星而言 ,进行星体姿态和天线指向复合控制的地面物理仿真试验研究是一个重要课题。本文主要叙述利用单轴气浮台模拟卫星姿态运动 ,由天线框架驱动机构 (GDA)实物连接组成的多体卫星平面运动动力学环境下的物理仿真试验系统。     

基于IGRF地磁场模型的航天器地磁干扰力矩数值仿真

航天器长期在轨运行期间,空间磁场与其自身磁矩相互作用的累积,会对航天器的姿态造成较大影响,加重姿态控制系统负担,降低航天器的可靠性。文章分别针对航天器轨道计算及地磁场模型的使用,对航天器地磁干扰力矩数值的仿真进行了系统的研究,最终得到航天器在轨运行时地磁干扰力矩计算仿真方法。     

高精度飞轮控制系统方案分析研究

卫星姿态控制是卫星控制领域里的最重要的一个方面 ,用于保证卫星的正常工作。一般的卫星姿态控制都采用飞轮控制方案 ,所采用的飞轮有磁悬浮飞轮和普通飞轮两种。虽然磁悬浮飞轮能克服飞轮自身摩擦力对卫星姿态的影响 ,但是磁悬浮飞轮在制造、工艺等方面要求高 ,而且成本昂贵。本文讨论了采用直流无刷电机控制普通飞轮的方案中关于转速和电流这两个关键参数的高精度控制问题 ,并给出了实际可行的解决方法。这些方法已在某型卫星上得到了部分应用。     

Motion of a satellite equipped with a pitch flywheel and magnetic coils in gravitational field

A satellite equipped with a magnetic attitude control system and a pitch flywheel has been considered. The system performance in the transient mode has been investigated. The characteristic exponent of the system have been approximated for a satellite on a circumpolar orbit. In the steady-state mode of gravitational attitude, small motions are considered in the vicinity of equilibrium. The attitude accuracy has been analyzed. The algorithm of an arbitrary but given attitude of the satellite in the orbital plane has been investigated. A numerical simulation has been performed.     

三轴稳定遥感卫星姿控系统故障情况下的系统重构

论述三轴对地稳定遥感卫星姿控系统中部分轮子或部分陀螺故障情况下的姿控系统重构。文中论述了只在俯仰通道有一偏置动量轮正常工作，而滚动和偏航通道轮子故障条件下的系统重构。另外还论述了偏航陀螺故障，姿控系统其它部件正常情况下，控制系统采用Whecon原理与PIM控制相结合的设计。以上两种系统重构拟用于实际系统中，经过数学仿真验证，姿控系统在故障情况下能够完成基本任务。     

基于OMNeT++的卫星姿态控制系统仿真

针对三轴稳定卫星的姿态控制系统,在离散事件仿真平台OMNeT 的基础上,建立了一个以星敏感器和陀螺为敏感器,反作用飞轮为执行机构的闭环控制仿真系统。采用双矢量定姿算法和PID控制算法,对该卫星在对地定向模式下的控制精度进行了仿真。仿真结果清晰地反映了星敏感器和反作用飞轮输出延时对控制精度的影响。整个仿真系统符合面向对象和模块化的程序设计理念,并实现了仿真程序的重用。     

卫星控制系统多转台多模拟器半物理仿真方法

卫星控制系统半物理仿真是在实验室中模拟卫星在轨道上运动特性的一种试验方法 ,它通常用于验证卫星控制系统方案和性能指标。卫星控制系统半物理仿真包括将硬件接入路的卫星动力学仿真和运动学仿真。仿真计算机计算卫星的动力学和运动学方程 ;转台模拟卫星在空间的运动 ;目标模拟器用来模拟作为卫星姿态敏感器的参考目标 (太阳、地球和恒星等 )的环境特性。为了将控制系统硬件接入试验路 ,必须适当地处理一系列的关键技术。卫星控制系统多转台多模拟器半物理仿真方法适用于带有多种敏感器的复杂卫星仿真。     

隔振平台对姿态控制系统影响分析及参数选择

为实现卫星的高精度高稳定度姿态控制,在控制力矩陀螺群(CMGs)和星体之间加装了隔振平台。首先依据整星动力学简化模型推得了隔振系统传递函数矩阵;然后分析了隔振平台的使用给姿态控制系统带来的影响,并提出了一种既能使CMGs隔振平台满足隔振要求,又能保证姿态控制系统充分稳定性的参数选择方案;最后通过数值仿真的方式验证了所提出的参数选择方案的合理性。     

Attitude control system of the first Russian nanosatellite <Emphasis Type="Italic">TNS-0 no. 1</Emphasis>

The results of designing the attitude control system of the first Russian nanosatellite TNS-0 no. 1 providing orientation of its longitudinal axis along the local geomagnetic field induction vector are presented. The system consists of a permanent magnet and two sets of hysteresis rods. The magnetic and geometric parameters of the magnet and rods are calculated. The influence of the permanent magnet field on the hysteresis rods and mutual influence of the rods in the case of compact satellite packaging are analyzed. Examples of calculations of transient processes and steady-state angular satellite motion are presented.     

连续力矩作用下的柔性航天器再定向与振动抑制

研究带两帆板航天器的三维再定向与振动抑制问题，执行机构为反作用轮。建立了柔性空间飞行器三轴耦合姿态动力学模型和四元数姿态运动学模型，建模时考虑了帆板的弯曲变形和扭转变形。采用拟欧拉角及角速度作为反馈信号，设计了一种ＰＤ控制律。该控制律可以用于对任意目标姿态的再定向而形式保持不变。用Ｌｙａｐｕｎｏｖ方法证明了姿态的渐进稳定性和模态振动和衰减性。非线性闭环系统的仿真结果验证了所设计控制律不仅能够使航天     

基于控制有效性因子的卫星姿态控制系统在轨重构容错控制

研究了在轨卫星姿态控制系统发生可修复性故障状况下的重构容错控制。首先在星敏感器对陀螺的标定模型中引入控制有效性因子，并利用二级卡尔曼滤波算法求解其值，以说明系统的控制有效程度。然后采用统计假设检验通过其幅值变化判断系统是否存在故障，当故障发生时，引入重构容错控制器对原控制器进行补偿控制。最后，建立卫星闭环姿态控制系统对算法进行了仿真验证，仿真结果表明该算法快速可靠，能够满足在轨卫星姿态控制系统故障状况下的性能要求。     

Periodic motions of a satellite-gyrostat relative to its center of mass under the action of gravitational torque

We investigated periodic motions of the axis of symmetry of a model satellite of the Earth, which are similar to the motions of the longitudinal axes of the Mir orbital station in 1999–2001 and the Foton-M3 satellite in 2007. The motions of these spacecraft represented weakly disturbed regular Euler precession with the angular momentum vector of motion relative to the center of mass close to the orbital plane. The direction of this vector during the motion was not practically changed. The model satellite represents an axisymmetric gyrostat with gyrostatic moment directed along the axis of symmetry. The satellite moves in a circular orbit and undergoes the action of the gravitational torque. The motion of the axis of symmetry of this satellite relative to the absolute space is described by fourth-order differential equations with periodic coefficients. The periodic solutions to this system with special symmetry properties are constructed using analytical and numerical methods.     

基于磁力矩定向阻尼特性的卫星姿态磁控制

根据磁力矩在地磁场中的定向阻尼特性，提出了磁控重力梯度和有阻尼器的非重力梯度卫星姿态控制律。给出了卫星姿态运动方程，并证明采用两种方法控制卫星姿态的稳定性。根据地磁场强度变化规律选择控制系数。理论分析和仿真结果表明，基于磁力矩定向阻尼特性的卫星姿态磁控制方法简单、精度较高。     

星敏感器测量模型及其在卫星姿态确定系统中的应用

星敏感器是卫星高精度姿态测量的重要部件，如何正确建立其测量误差模型是影响姿态确定精度的关键因素。本文推导出星敏感器三轴姿态测量误差的方差计算公式，对测量误差的性质进行研究，揭示了在星敏感器三轴测量中，光轴测量精度劣于根据另两轴测量所确定的光轴指向精度。在此基础上提出了新的星敏感器测量模型，给出改进的姿态滤波器观测方程，减小了观测误差，由此可以进一步提高姿态确定的精度。本文方法不仅适用于通常使用的双星敏感器姿态确定系统，也可独立地应用于只带单个星敏感器的姿态确定系统。