一种偏置动量轮在轨维护的变带宽控制方法

针对长寿命运行卫星在轨维护中出现的备份偏置动量轮离散性差异较大,导致俯仰角收敛缓慢的问题,在姿态现象分析的基础上,根据卫星姿态动力学原理,建立偏置动量轮工作模式下的俯仰姿态的PID(Proportion Integration Differentiation,比例积分微分)控制模型,并进行系统开环与闭环传递函数公式推导。然后在伯德图(Bode Diagram)基础上,重点分析相位裕量的敏感参数,给出俯仰姿态控制回路的带宽调整方法,实现变带宽控制。卫星偏置动量轮在轨切换维护的结果表明,通过及时调整PID参数,减小回路带宽,可以有效改善相位裕量,保持卫星控制性能,实现俯仰姿态快速收敛,且俯仰角控制精度优于0.03°,取得较好的应用效果。     

利用能量/动量飞轮的偏置动量姿态控制系统

研究偏置动量姿态控制系统中的集成能量与姿态控制问题。利用一对正 反转飞轮提供偏置角动量并同时储 /放能以满足星载设备的能源需求。滚动 /偏航运动由俯仰轴磁矩控制。设计了力矩形式的飞轮的控制律 ,使之提供期望的俯仰控制力矩 ,并以给定的功率储 /放能。保持两只飞轮正 反转可以完全避免飞轮控制律中的系统奇异。提出了利用动能反馈的飞轮储能功率规划方案 ,以使系统维持能量平衡 ,避免由于能量过剩引起的飞轮饱和。飞轮的最小转动惯量受最大偏置角动量和最小能量的限制 ,结合几何方法对这种限制条件进行了分析。数值仿真结果证明了控制方案的有效性。     

跟踪弹道导弹时预警卫星姿态前馈协同控制

基于角动量守恒定理,推导了跟踪弹道导弹时,具有活动部件的预警卫星姿态前馈协同控制。该控制算法基于角动量守恒方程估计红外相机运动产生的角动量扰动以及为抑制该扰动所需的期望飞轮转速,将期望飞轮转速与实际转速的偏差作为前馈信号加入到传统控制系统中,推导出预警卫星姿态前馈控制模型。最后通过数值仿真验证了控制方法,仿真结果与理论分析具有很好的一致性。并且该控制方法简单、可靠,能够适应卫星在轨实时控制。     

Attitude control of a bias momentum satellite using moment ofinertia

Analysis on the attitude controller based upon moment of inertia distribution for a bias momentum satellite is discussed. Spacecraft moment of inertia distribution is represented in the form of product of inertia terms in the system inertia matrix. The product of inertia between orthogonal body axes of the satellite is used to build a controller which controls the nutational motion caused by the angular momentum of the wheel. The attitude controller in the pitch axis controlling the pitch motion as well as nutational dynamics in the roll/yaw planes is analyzed in detail. Analytic expressions using linearized equations are derived providing further insight into the dynamic coupling effect among orthogonal body axes     

Attitude control system design and on-orbit performance analysis of nano-satellite––‘‘Tian Tuo 1’’

‘‘Tian Tuo 1'(TT-1) nano-satellite is the first single-board nano-satellite that was successfully launched in China. The main objective of TT-1 is technology demonstration and scientific measurements. The satellite carries out the significant exploration of single-board architecture feasibility validation, and it is tailored to the low-cost philosophy by adopting numerous commercialoff-the-shelf(COTS) components. The satellite is featured with three-axis stabilization control capability. A pitch bias momentum wheel and three magnetic coils are adopted as control actuators.The sun sensors, magnetometers and a three-axis gyro are employed as the measurement sensors.The quaternion estimator(QUEST) and unscented Kalman filter(UKF) method are adopted for the nano-satellite attitude determination. On-orbit data received by ground station is conducted to analysis the performance of attitude determination and control system(ADCS). The results show that the design of ADCS for TT-1 is suitable, robust and feasible.     

基于扩展卡尔曼滤波的动量轮故障检测方法

 动量轮作为卫星姿态控制系统的关键执行部件,对其故障检测对维持卫星的正常运行具有重要意义。首先对动量轮系统的故障进行分析,在建立动量轮线性离散状态空间模型的基础上,把动量轮的故障检测作为时变参数系统的跟踪来处理,将动量轮的模型参数作为扩展的状态空间中的状态量,使得动量轮物理模型参数与状态空间中的状态量有对应关系,通过在扩展了的状态空间上采用扩展的卡尔曼滤波,完成时变参数的跟踪。然后,将离散空间的状态量变换回连续空间中,利用物理参数与状态量的对应关系,实现对动量轮物理参数的跟踪。此方法物理意义明确,为系统的物理参数提供了定量的估计值,为进一步诊断故障原因提供了良好的基础。数值仿真表明,此方法能够通过同时检测多个故障参量,实现故障的检测并满足卫星实时性要求。     

Large angle pitch attitude maneuver of a satellite using solarradiation pressure

The force exerted by the solar radiation, though very small in magnitude, produces significant effects, especially in the case of high altitude satellites. The solar radiation pressure represents one freely available environmental force that may be put to use for various purposes. This may lead to enhancement of the life of the satellite since it consumes a very nominal amount of on-board energy. The advantages offered by the solar radiation pressure have drawn the attention of several researchers. Various controllers were proposed for many space missions, particularly for attitude control and stabilization of satellites. A controller for achieving large angle pitch attitude maneuver is described. The proposed control law is very simple in its form and requires a minimum number of on-board computations. Varieties of cases are tried and the effect of various parameters is studied     

卫星动量轮灵敏性变异分析

基于模糊理论提出一种非线性卫星动量轮灵敏性变异分析的数值方法,以工程实际中的模糊相似关系转化为空间向量的模糊等价关系,来评估稳定系统的总体变异本质特征.并通过仿真均匀分布、线性分布以及周期分布的时间数据序列验证了该模型的可行性;以3套卫星动量轮实际稳态运转实验见证了该方法的实用性和有效性.其中动量轮A的最小灵敏系数为0.678,大于0.5阈值,表明其运转期间灵敏性十分良好;动量轮B的最小灵敏系数为0.439,小于0.5阈值,其运转期间灵敏性有所变异;动量轮C的最小灵敏系数等于0.5阈值,其关系最为模糊并介于稳定与变异之间.该模型实时预测并描述了动量轮灵敏性变异过程,且适用于诸多航天领域的非线性乏信息问题.      

基于动量轮转速标定的轨道控制方法研究

某地球同步三轴卫星因故障导致推力器工作效率不稳定,使得采用原有方案进行向西轨道控制时姿态变化大,控制准确度降低.针对上述问题,通过分析卫星用于姿态控制的偏置动量轮的控制规律,利用星体角动量守恒条件,建立了偏置动量轮转速变化与轨道半长轴变化之间的相关性数学模型,提出了一种改进的基于偏置动量轮转速标定的轨道控制方法,同时结合姿态的稳定变化制定了轨道控制实施方案,并将其应用于实际卫星轨道控制中,取得了良好的控制效果.改进的控制方法提高了轨道控制的准确率,使得半长轴误差幅度由最大60％提高到0.2％左右,增加了姿态的稳定性,使得俯仰姿态变化幅度由最大0.7°减小到0.2°左右,降低了控制风险,减轻了地面控制人员的负担.     

利用飞轮的航天器姿态跟踪与能量存储

研究航天器集成能量与姿态控制系统中飞轮的控制律。系统中飞轮是姿态控制的执行机构,同时也是储能装置。首先利用Lyapunov方法设计了航天器姿态跟踪的反馈控制律,然后研究一种力矩形式的飞轮控制律。利用奇异值分解方法把飞轮组的控制力矩向量分解为3部分相互正交的力矩向量,一部分用来提供姿态控制力矩,一部分用来以给定的功率储能,另一部分完成轮速平衡以避免由于各飞轮轮速差异过大引起的飞轮饱和。提出了一种基于动能反馈的储能功率规划方案来保证系统的能量平衡,可以避免由于过剩能量引起的飞轮饱和。数值仿真结果验证了控制方案的有效性。     

Tethered dual spacecraft configuration: a solution to attitude control problems

A new dual spacecraft configuration comprising of two spacecraft halves judiciously connected through extremely short tethers is proposed. The simple tethered configuration induces stabilizing torques when subjected to attitude disturbances, thus ensuring 3-d pointing stability of both the satellite platforms. The enhanced system performance obtained using tethers enables a much greater flexibility in the choice of satellite mass distribution. Three particular TSS models involving parallel tethers, a `parachute-like' conical tether layout as well as a single tether connection have been considered. A detailed numerical response simulation shows that these modes of tether attachments bring about a radical change in the satellite attitude behavior from the nominal one involving relatively large librational amplitudes or instability to a virtually fixed desired orientation. Of these, the parachute configuration appears to be superior. The passive nature of the proposed mechanisms using tether lengths on the order of merely a couple of meters needed for small and medium size systems makes the concept particularly attractive for future space missions. Finally, it is felt that the proposed tethered dual satellite systems may offer a simple answer to three-axis attitude control problems.     

基于新型音轮的涡桨发动机桨距-相角-转速一体化测量研究

为了有效解决多传感器安装的困难和音轮转子不平衡问题,研究了一种基于新型音轮的涡桨发动机桨距-相角-转速一体化测量方法,提出带有多个常规齿和一组对称标志斜齿的新型音轮结构,经过信号处理模块把传感器波形调理成方波,分析方波边沿时刻就能获取螺旋桨的桨距、相角和转速。通过COMSOL数值仿真研究了不同音轮结构对电压波形及测量精度的影响,设计了涡桨发动机桨距-相角-转速一体化测量试验台。试验结果表明,在非极端齿位差角范围内,桨距和相角的误差曲线呈现很好的线性特性,经过线性补偿修正后,桨距、相角和转速测量精度可以分别控制在±0.7%,±0.05%和±0.027%,可以满足涡桨发动机控制精度需求。     

精确轨道航天器的姿态机动策略选择

航天器姿态控制一直是地面飞控的核心,尤其对于有精确轨道控制要求的航天器,姿态控制的策略选择直接关系任务成败。探月三期月地高速再入返回任务对再入角有着严格要求,为了实现返回器高精度再入,在系统介绍服务舱的姿态控制模式、控制方法和控制流程的基础上,提出了利用修改相平面参数和轮控调姿,以建立轨控姿态,从而减少姿控喷气,并提高轨控精度的方法。飞行结果表明,中途修正的控制精度从最初的分米量级提高至0.009m/s。高精度轨道控制使得提前32h再入角控制精度达到0.024°,较设计指标提高1个数量级。文中提及的轮控调姿方法可作为未来深空探测任务姿态控制的设计参考。     

轻型高精度卫星的变结构姿态控制器

针对某些小卫星高指向精度和高稳定精度的姿态控制要求,设计了能克服反作用轮转速过零扰动的变结构姿态控制器,并对反作用轮转速过零时低速摩擦对卫星姿态产生扰动的机理进行了分析,建立了仿真用反作用轮低速摩擦动力学模型。同 PID控制器相比,该变结构姿态控制器能有效抑制反作用轮的低速摩擦影响,并具有良好的鲁棒性。数学仿真进一步证明了该变结构姿态控制器的有效性,其指向精度和稳定精度分别可达 0.3°和 0.0 0 1°/     

Adaptive controller design for satellite attached by non-cooperative object

When non-cooperative body attachment occurs in space, the inertia of the new combination and the change of the system’s momentum are unknown. This uncertainty may lead to the instability of the spacecraft’s attitude control. In order to solve this problem, we propose an adaptive control scheme based on the inertia estimation of the new, combined system of non-cooperative body and satellite. This method can allow the new combination of different situations to reach a stable state with a high level of precision and speed. In this paper, the stability of the adaptive control scheme is proven by constructing a Lyapunov function. A simulation environment in which a non-cooperative body attaches to a satellite attaches to is constructed. The simulation shows that the attitude error converges to a small field when using the control scheme, regardless of unfavorable cases, including unknown inertia parameters, added momentum. In addition, the simulation results show the strong robustness of the control scheme for the new combination.     

过驱动轮控卫星的动态控制分配方法

反作用飞轮在卫星姿态控制中具有重要作用,配置3个以上飞轮的卫星构成一类过驱动系统,能够提高姿态控制系统的可靠性.针对期望控制力矩到冗余飞轮的指令分配问题,提出了一种基于伪逆法的动态控制分配方法,并针对传统伪逆法难以考虑飞轮最大力矩等物理约束问题,采用零空间方法对传统伪逆法给出的分配结果进行了修正.基于稳定控制模式下姿态...     

小卫星主动磁控制地球捕获姿态控制系统设计

分析了小卫星捕获阶段的客观条件要求,重力梯度杆的指向要求,捕获阶段视为大角度机动问题,采用欧拉动力学和四元数方法描述,建立小卫星捕获阶段的动力学模型。控制器采用大角度机动拟 PD控制,拟PD控制器参数采用了简化分析和经验调试设计,同时分析设计了磁力矩器的磁偶极子,最后给出某小卫星姿态捕获仿真结果,经过几个轨道周期后可以实现一定精度的对地捕获,验证了本文的设计方法的可行性。     

考虑输入饱和的两飞轮驱动航天器视线轴控制

 研究了非零初始整星角动量下两飞轮驱动航天器姿态机动控制问题,针对在两飞轮旋转轴平面外某一视线轴的指向控制,给出了目标姿态生成算法和一种抗输入饱和的视线轴指向滑模控制算法。首先,通过对两飞轮驱动航天器静止时的可行姿态进行分析,给出了视线轴指向目标方向的必要条件。然后,基于该条件得到了使视线轴与目标方向偏差最小的目标姿态。最后,对状态方程进行降维和线性化处理,设计了一种抗输入饱和的视线轴指向滑模控制算法。仿真结果展示了本文算法的可行性和有效性。     

A view finder control system for an earth observation satellite

A real time TV view finder is used on-board a low earth orbiting (LEO) satellite to manually select targets for imaging from a ground station within the communication footprint of the satellite. The attitude control system on the satellite is used to steer the satellite using commands from the groundstation and a television camera onboard the satellite will then downlink a television signal in real time to a monitor screen in the ground station. The operator in the feedback loop will be able to manually steer the boresight of the satellite's main imager towards interested target areas e.g. to avoid clouds or correct for any attitude pointing errors. Due to a substantial delay (in the order of a second) in the view finding feedback loop and the narrow field of view of the main imager, the operator has to be assisted by the onboard attitude control system to stabilise and track the target area visible on the monitor screen.This paper will present an extended Kalman filter used to estimate the satellite's attitude angles using quaternions and the bias vector component of the 3-axis inertial rate sensors (gyros). Absolute attitude sensors (i.e. sun, horizon and magnetic) are used to supply the measurement vectors to correct the filter states during the view finder manoeuvres. The target tracking and rate steering reaction wheel controllers to accurately point and with high agility stabilise the satellite, will be presented. The controller reference generator for the satellite-to-target attitude and rate vectors, as used by the reaction wheel controllers, will be derived.     

纳卫星变轨段质量矩姿态控制系统设计

提出应用质量矩控制技术实现纳卫星轨道机动过程中的姿态稳定控制。在设计出质量矩滑块构型后,利用动量和动量矩定理推导了八自由度(DOF)动力学模型,并根据动力学分析结果建立了简化控制模型。以此为基础,基于全局滑模控制理论设计了俯仰偏航通道姿态稳定和滑块位置跟踪的鲁棒控制器,并在参数不确定性条件下对控制系统进行了仿真,结果表明:所设计的二维质量矩控制系统能快速控制卫星姿态,并对系统扰动具有较强的鲁棒性,可以应用于纳卫星变轨段的姿态控制。