无陀螺磁控小卫星的大角度姿态捕获研究

为了解决无陀螺磁控小卫星的姿态稳定和捕获问题,本文针对偏置稳定的主动磁控小卫星姿态控制平台,基于磁控力矩的时间累积作用效果等效卫星角动量增量的规律,设计了一种仅利用角度反馈的卫星大角度磁捕获控制律。通过仿真和卫星在轨实测的验证,证明该方法具有良好的收敛效果和鲁棒性,工程实现简单,可靠性高,适用于中低轨道的通信小卫星。     

失效航天器姿态接管的SDRE微分博弈控制

针对燃料耗尽的失效航天器姿态接管控制问题,提出多颗微卫星协同实现姿态稳定的状态相关黎卡提方程(SDRE)微分博弈控制方法。首先,将姿态接管问题转化为多颗微卫星的微分博弈问题,基于组合航天器的姿态模型和微卫星的性能指标函数建立多颗微卫星的非线性微分博弈模型,微卫星通过独立优化各自的性能指标函数得到控制策略。其次,引入状态相关系数矩阵,将非线性博弈转化为状态相关线性二次型博弈,采用SDRE方法更方便地逼近微卫星的博弈均衡策略。最终通过李雅普诺夫迭代法求解耦合状态相关黎卡提方程组得到微卫星的状态反馈控制器,实现微卫星的自主决策。数值仿真验证了多颗微卫星采用微分博弈控制方法实现姿态接管的有效性和容错性。     

Three-axis active control system for gravity gradient stabilised microsatellite

In this paper, the control system of the first Algerian microsatellite in orbit Alsat-1 is presented. Alsat-1 is a 3-axis stabilised microsatellite, using a pitch momentum wheel and yaw reaction wheel, with dual redundant 3-axis magnetorquers. A gravity gradient boom is employed to provide a high degree of platform stability. Two vector magnetometers and four dual sun sensors are carried in order to determine the attitude. This paper examines the low Earth orbit (LEO) control system requirements and design in the context of a real system, the Surrey Satellite Technology Limited (SSTL) advanced microsatellite platform and puts forward designs for the control system to match the advanced capability of the enhanced microsatellite platform. Numerical results show the effectiveness of the implementation. Comparison with in orbit results is presented to evaluate the performance of the control system during accurate Nadir pointing control.     

微小卫星多约束姿态机动规划方法

针对微小卫星姿态控制中存在的多重指向约束和角速率约束问题,提出一种基于对数型势函数的多约束姿态机动规划方法。首先针对微小卫星携带的光学传感器需躲避强光天体而天线需指向地面保证对地通信这一约束特性,采用对数型势函数方法保证约束姿态指向满足任务要求;其次,针对姿态角速率限制的问题,引入障碍Lyapunov函数确保姿态角速率始终处于约束范围内。与在线优化方法相比,该方法具有计算量小的显著优势,非常适合星上处理能力有限的微小卫星。此外,考虑外界干扰力矩的影响,引入自适应干扰估计律,增强了控制系统的鲁棒性。最后,通过数学仿真对本文方法进行了校验,仿真结果表明,该方法能够快速实现卫星姿态机动到期望指向,与此同时,在整个姿态机动过程中,均满足多重指向约束和姿态角速率约束 要求 。     

New one-axis one-sensor magnetic attitude control theoretical and in-flight performance

New one-axis magnetic attitude control is proposed. Only one attitude sensor providing any inertial direction measurements is necessary, magnetometer is not used. The control may be used as a backup capability in case main actuators or some attitude sensors fail. Sun pointing is achievable using only three-axis Sun sensor, so the control may be used to lower the power consumption during battery charging. Asymptotic stability of different equilibria depending on the satellite inertia tensor is summarized. In-flight results from “Chibis-M” microsatellite are provided proving general control performance.     

The results of flight tests of an attitude control system for the Chibis-M microsatellite

The attitude control system of the Chibis-M microsatellite is described. Results of flight experiments on damping the initial angular velocity (made using magnetorquers) are considered, as well as stabilization in the orbital referece frame, and orientation of solar arrays toward the Sun using reaction wheels. The operation of algorithms of satellite attitude determination on sunlit and shadow segments of the orbit is also under study. The general logic of operation of the attitude control system in automatic mode is presented and discussed.     

基于切变流形函数和模糊控制的微小卫星姿态磁控制

研究了一种用李亚普诺夫方法和模糊控制理论实现微小卫星姿态磁控制的方法。通过构造李亚普诺夫函数给出切变流形函数,获得了一开关控制,并从理论上证明了系统的收敛性。用模糊控制法消除常规开关控制固有的抖振,给出了模糊控制律。理论分析和仿真结果表明,该姿态磁控制方法简单、姿态精度高、鲁棒性强,可用于微小卫星的姿态磁控制。     

Three-axial fiber optic gyroscope

We consider a new design of a high-precision three-axial sensor of angular velocities whose sensitive elements are fiber optic gyroscopes using the Sagnac effect. The instrument is designed for measuring the rotation velocity of an orbiting spacecraft (microsatellite) and for performing its attitude control.     

Development,integrated investigation,laboratory and in-flight testing of Chibis-M microsatellite ADCS

Design, analytical investigation, laboratory and in-flight testing of the attitude determination and control system (ADCS) of a microsatellites are considered. The system consists of three pairs of reaction wheels, three magnetorquers, a set of Sun sensors, a three-axis magnetometer and a control unit. The ADCS is designed for a small 10–50 kg LEO satellite. System development is accomplished in several steps: satellite dynamics preliminary study using asymptotical and numerical techniques, hardware and software design, laboratory testing of each actuator and sensor and the whole ADCS. Laboratory verification is carried out on the specially designed test-bench.In-flight ADCS exploitation results onboard the Russian microsatellite “Chibis-M” are presented. The satellite was developed, designed and manufactured by the Institute of Space Research of RAS. “Chibis-M” was launched by the “Progress-13M” cargo vehicle on January 25, 2012 after undocking from the International Space Station (ISS). This paper assess both the satellite and the ADCS mock-up dynamics. Analytical, numerical and laboratory study results are in good correspondence with in-flight data.     

A residual based adaptive unscented Kalman filter for fault recovery in attitude determination system of microsatellites

This paper presents an adaptive unscented Kalman filter (AUKF) to recover the satellite attitude in a fault detection and diagnosis (FDD) subsystem of microsatellites. The FDD subsystem includes a filter and an estimator with residual generators, hypothesis tests for fault detections and a reference logic table for fault isolations and fault recovery. The recovery process is based on the monitoring of mean and variance values of each attitude sensor behaviors from residual vectors. In the case of normal work, the residual vectors should be in the form of Gaussian white noise with zero mean and fixed variance. When the hypothesis tests for the residual vectors detect something unusual by comparing the mean and variance values with dynamic thresholds, the AUKF with real-time updated measurement noise covariance matrix will be used to recover the sensor faults. The scheme developed in this paper resolves the problem of the heavy and complex calculations during residual generations and therefore the delay in the isolation process is reduced. The numerical simulations for TSUBAME, a demonstration microsatellite of Tokyo Institute of Technology, are conducted and analyzed to demonstrate the working of the AUKF and FDD subsystem.     

A study of angular motion of the Chibis-M microsatellite with three-axis flywheel control

We study the controlled angular motion of the Chibis-M microsatellite. Executive elements are three pairs of flywheels, whose axes are mutually perpendicular. The task of the control system is realization of a required program motion and support of its asymptotic stability. In this paper, we synthesize a control algorithm and study the evolution of the angular momentum of flywheels on long time intervals. The attitude accuracy is estimated for the case when disturbances act upon the spacecraft.     

采用观测器的偏置动量小卫星姿态容错控制

针对偏置动量小卫星的自主飞行问题,提出一种基于不确定项观测器的滑模容错控制方法。应用欧拉-拉格朗日系统的干扰观测方法设计不确定项观测器,对动量轮输出力矩变小、磁力矩器线圈电阻漂移等执行器故障以及小卫星外部环境力矩等不确定项进行估计,理论推导证明该观测器的观测误差一致最终有界(UUB)。基于不确定项观测器的估计值,设计补偿控制项,并与滑模控制器的控制力矩合成实现姿态容错控制。从理论上证明该容错控制方法能够使小卫星姿态快速收敛至滑模面。该容错方法无需做小角度假设,对执行器运行状态信息依赖性低。仿真结果表明,本文建议的容错控制方法具备可行性,实现了对小卫星姿控系统中不确定项的观测估计和容错控制。     

Multi-objective output-feedback control for microsatellite attitude control: An LMI approach

Mixed H₂/H_∞ output-feedback controller with pole placement constraints against the internal uncertainty of moment-of-inertia variation and space environmental disturbances is proposed for mircosatellite attitude control. The multi-objective controller is designed based on linear model of attitude dynamics. The H_∞ performance takes into account both robustness stability against moments-of-inertia uncertainty and the disturbance rejection aspect. H₂ performance takes into account the LQG aspect which avoids the undesirable wheels’ saturation effect. In addition, the closed-loop poles can be forced into some sector of the stable half-plane to obtain well-damped transient responses. The problem is then reduced to a convex optimization involving linear matrix inequalities (LMIs), so it can be efficiently solved. The simulation results demonstrate that the presented mixed H₂/H_∞ control system is robust stable and optimal in the sense of H₂ norm, and has good steady-state and dynamic performances against the parameter uncertainties and various disturbances for the microsatellite attitude control system.     

电分离连接器对小卫星星箭分离干扰分析

电分离连接器是否成功分离是卫星与火箭分离过程中一个重要的环节。文章以某小卫星为工程背景,根据电分离连接器具有电分离（正常）和机械分离（非正常）两种工作模式,给出了小卫星在正常分离模式和非正常分离模式下的分离时序,建立了两种分离模式下的分离力学模型,开展了电分离连接器分离的仿真分析。结果表明:正常分离模式下,分离不存在干扰;非正常分离模式下存在少许分离干扰,但卫星可以实现安全分离。     

The dive and ascent satellite program for lower ionosphere research

Lower ionosphere is a transition region from outer-space to low atmosphere and had been unexplored on a continuous basis before Atmosphere Explorer satellites flew in the region. Purpose of a new aeronomy satellite, DAS (Dive and Ascent Satellite) having a capability to control orbits and flying at the very low perigee altitude less than 130 km is to explore the bottomside of ionosphere spreading over between 100 and 300 km altitudes. Preliminary study on the new aeronomy satellite is conducted at National Aerospace Laboratory in cooperation with Radio Research Laboratories and Meteorological Research Institute.This paper reviews the mission design, orbit decay and transfer analysis, typical orbit profile, aerodynamic characteristics and satellite configuration study, aerodynamic heating and thermal control analysis, attitude control analysis, on-board propulsion and power subsystems, and operation analysis with emphasis on their technical feasibility.     

一种GPS双频多天线姿态测量方法

北京遥测技术研究所自主研制的双频GPS-OEM板可以提供精度很高的双频载波相位原始观测数据,利用其对载体进行姿态测量,将是一种即经济又方便的工作方式,而且还能获得很高的精度和稳定性。基于此展开对双频GPS载波相位测姿的研究工作,结合双频GPS载波相位可以组合出86 cm波长宽巷载波相位观测值的特性,基于伪距和载波相位组合获取模糊度搜索空间,再使用最小二乘降相关平差法(LAMBDA方法)搜索整周模糊度。大量的试验数据证明,利用双频GPS载波相位进行测姿切实可行,姿态初始化速度快,测姿结果精度高。     

微小型双组元姿控发动机技术研究

高性能微小型液体双组元姿控发动机具有冲量小、响应快、质量轻、尺寸小等特点,可为微小卫星等航天器实现在轨精确姿态控制,延长在轨工作寿命以及轻小型化等方面的应用提供技术基础.本文以5N微小型双组元液体火箭发动机为例,从微小型喷注器设计、微小型阀门设计、微小尺寸构件成型技术、热相容设计等方面,详细介绍了上海空间推进研究所在微小型双组元发动机设计及制备方面取得的进展和成果,提出了该项目的后续研制计划.     

采用单目视觉的非合作目标星状态估计

针对微小卫星逼近观测未知的空间翻滚非合作目标星任务，提出一种基于单目视觉的目标星相对状态估计方法。在建立追踪星/目标星相对运动模型的基础上，以单目相机识别并测量获得的目标星固有特征的像素位置为观测输入，通过扩展卡尔曼滤波算法实现对目标星相对位置、相对速度、相对姿态、角速度、惯量比和特征位置等状态的估计。仿真结果表明,该方法能够很好地实现对未知非合作目标星的相对状态估计，姿态估计误差小于2°，位置估计误差小于0.1 m，特征点位置平均估计误差小于0.04 m。     

空间拦截器姿态控制系统变结构控制规律研究

结合空间拦截器的姿态控制问题,本文介绍了一种对系统参数摄动和外在不确定性干扰具有鲁棒性的变结构控制律。在此基础上,研究了当控制信号幅值受限的情况下,非线性系统的变结构控制律的设计问题。此方法考虑了空间拦截器姿控发动机推力幅值受限这一实际情况,提出了基于姿态角双包络线概念的实用姿控方法。因此,更符合系统实际的运行情况。仿真结果证明了此方法的有效性。     

试验运载器姿控总体优化设计技术

试验运载器在姿控动力系统空间布置紧张、控制力臂有限的情况下，要实现初始起控阶段大初始姿态偏差及气动干扰条件下的稳定控制，以及有效载荷释放阶段的多通道多次连续大角度调姿控制，给姿控系统的设计造成了困难。为此，通过鸭式直接力控制方案设计、多通道连续大角度调姿方案设计等技术，设计出了满足任务要求且性能良好的姿控总体方案。