基于数据驱动的航天器三维可视化系统设计

航天器数据庞大繁杂,为了给设计人员提供快速检验设计思想的便捷工具,对基于数据驱动的航天器三维可视化系统进行了研究。在分析航天器可视化系统特点的基础上,提出系统功能要求,继而提出了基于数据驱动的三维可视化系统构建方案,介绍了可视化系统组成、核心模块关系。在基于MFC框架及Vega Prime为主的开发的前提下,对系统模块划分进行了研究,给出模块功能和实现方案。为了提升系统展示效果,对消息缓冲与插值延迟、特效集成与驱动机制、相机管理和场景切换等关键技术提出了优化设计方案,使之更加适应航天器可视化展示需求。设计系统较传统可视化系统展示更为流畅,场景视角切换更为智能。系统已应用于多个航天器研发工作中,应用效果证明系统具有良好的通用性和实用性,具有一定的推广价值。     

基于DSP的航天器压力变化检漏仪的设计

航天器的密封性能是极其重要的指标之一,利用压力变化方法进行舱体密封性检漏是保障其密封性的重要技术手段;设计研制小型压力变化检漏仪对满足航天器检漏设备小型集成化、高精度的迫切需求是十分重要的;以DSP为数据的核心处理器,分析绝压和差压具有温度补偿方法,设计基于485通信接口实现数字绝压传感器的数据采集,采用250Ω的高精度电阻接入电流环的方法实现差压传感器的信号调理,通过ADS1247高精度24位数模转换器实现差压信号的采集;并采用恒流供电和电阻比测量原理实现对两路热敏电阻温度传感器的测量;各信号经DSP中固化的压力变化检漏算法集中处理,得到被测物体的漏率值,检测结果通过LCD显示。所研制集绝压、差压和温度多参量监测于一体的检漏仪,经过温度、压力、检漏试验等测试,验证了其精度和检漏能力满足要求;研究结果表明：所研制的检漏仪小巧,精度高,可靠性高,可实现压力、温度、漏率等多参量的同时监测,漏率检测的最大相对误差为19.3%,相对不确定度小于2%,可有效地解决航天器泄漏检测的问题。     

Ka频段飞行器测控与通信系统设计

传统基于S频段的统一载波测控系统受工作频率低、频带窄的特点限制,无法满足各类飞行器测控与通信系统对高速数传、宽带扩频、克服“黑障”、抗干扰等方面日益增长的需求,给系统设计带来了新的挑战。本文提出一种基于Ka频段直接序列扩频通信体制的实现遥测、外测、遥控等功能的飞行器测控与通信系统,给出了系统架构及主要设备组成,同时对地面测试方案进行了介绍。该系统具备体积小、频带宽、扩展性好等特点,可用于未来空间飞行器特别是小型化、大容量飞行器设计。     

航天器多路射频频谱自动监测系统设计

设计了一种采用太阳能供电模式的无线户外环境监测系统。该系统由终端节点,ZigBee-GSM网关和上位机数据存储中心组成,集成ZigBee和GSM无线通信,根据用户发送的短信指令控制终端节点数据采集的通断,同时用户发送短信指令远程查询户外环境的重要信息。针对户外环境因子的特点,选用工业级、灵敏度高的传感器,对户外不同位置的PM2.5浓度和紫外线指数进行测量,测量结果既可在上位机实时显示和存储,也可以由ZigBee-GSM网关通过SIM900A模块发送至移动终端。户外测试结果表明,该系统运行稳定,数据传输可靠,能快速地实现远程遥测功能,为户外环境远程监测提供了一种技术手段。     

Analytical solutions for dynamics of dual-spin spacecraft and gyrostat-satellites under magnetic attitude control in omega-regimes

The attitude dynamics of a dual-spin spacecraft (a gyrostat with one rotor) with magnetic actuators attitude control is considered in the constant external magnetic field at the presence of the spacecraft’s own magnetic dipole moment, which is created proportionally to the angular velocity components (this motion regime can be called as “the omega-regime” or “the omega-maneuver”). The research of the dual-spin spacecraft angular motion under the action of the magnetic restoring torque is fulfilled in the generalized formulation close to the classical mechanics’ task of the heavy body/gyrostat motion in the Lagrange top. Analytical exact solutions of differential equations of the motion are obtained for all parameters in terms of elliptic integrals and the Jacobi functions. New obtained analytical solutions can be classified as results developing the classical fundamental problem of the rigid body and gyrostat motion around the fixed point. The technical application of the omega-regime to the angular reorientation of the spacecraft longitudinal axis along the angular momentum vector is considered.     

基于无迹粒子滤波的飞行器再入段传递对准方法

针对再入式飞行器再入返回前需要精确和快速的传递对准需求以及空间环境特殊性,提出了一种适用于再入式飞行器空间平台对准方法,建立J2000坐标系下光纤陀螺惯组的系统状态方程,利用星敏感器输出的姿态和光纤陀螺惯组输出的姿态差值作为观测量,实现飞行器的"姿态"匹配传递对准算法。针对系统状态方程和量测方程的非线性特性以及单独使用无迹卡尔曼滤波(UKF)方法存在滤波不稳定性和单独使用粒子滤波(PF)方法存在粒子退化导致估计误差变大的问题,提出了无迹粒子滤波(UPF)算法,采用卫星工具包(STK)软件模拟飞行器在轨运行进行仿真验证。仿真结果表明:该方法可以在3s内使得失准角的估计误差小于0.6',估计精度提高了30%,收敛时间缩短了70%,相比传统方法提高了对准的精确性和快速性。     

杆式射流对充液防护结构的毁伤机理及影响因素的数值模拟

运用ANSYS/LS_DYNA软件分析了聚能射流对充液结构的毁伤,初步获得了药型罩壁厚和材料等参数对聚能战斗部水下作用的影响特性。药型罩壁厚在0.04D_k~0.06D_k(D_k为装药直径)之间形成的射流对充液防护结构具有较优的侵彻性能;当δ<0.04D_k时,杆流成型结构较差,在水中的动能抗衰减性能较低;δ>0.06D_k时,射流的初始动能低,靶后效果差。药型罩可采用纯铁、紫铜和钽3种材料,其中纯铁射流的侵彻能力最高,钽射流在水中的动能抗衰减性能最好,紫铜射流具有较好的综合性能。     

X射线脉冲轮廓稳定性对导航精度的影响

X射线脉冲星具有广阔的导航应用前景,稳定的脉冲轮廓是自主导航的基础,然而在X射线脉冲轮廓的稳定性及其对导航精度的影响方面一直缺乏系统的研究.采用Pearson相关系数、标准偏差及功率谱熵三组指标量化脉冲轮廓的稳定性.利用罗西X射线计时探测器卫星X射线段(2—16 keV)11年的观测资料,统计了包括周期跃变在内的Crab脉冲轮廓稳定性.在此基础上,引入Cramer-Rao理论建立了脉冲轮廓稳定性对距离测量误差影响的数学模型,并通过分析各误差因素确定脉冲轮廓稳定性对距离测量误差的影响范围.实测数据处理表明,Crab脉冲星的X射线脉冲轮廓具有极高的稳定性,跃变期间脉冲轮廓无明显变化,脉冲轮廓的稳定性导致沿脉冲星方向上产生34 m±25 m的距离测量误差.     

Robust attitude control for rapid multi-target tracking in spacecraft formation flying

A robust attitude tracking control scheme for spacecraft formation flying is presented. The leader spacecraft with a rapid mobile antenna and a camera is modeled. While the camera is tracking the ground target, the antenna is tracking the follower spacecraft. By an angular velocity constraint and an angular constraint, two methods are proposed to compute the reference attitude profiles of the camera and antenna, respectively. To simplify the control design problem, this paper first derives the desired inverse system （DIS）, which can convert the attitude tracking problem of 3D space into the regulator problem. Based on DIS and sliding mode control （SMC）, a robust attitude tracking controller is developed in the presence of mass parameter uncertainties and external disturbance. By Lyapunov stability theory, the closed loop system stability can be achieved. The numerical simulations show that the proposed robust control scheme exhibits significant advantages for the multi-target attitude tracking of a two-spacecraft formation.     

Heteroclinic bifurcations in completely liquid-filled spacecraft with flexible appendage

In this paper, the chaotic dynamics in an attitude transition maneuver of a rigid body with a completely liquid-filled cavity in going from minor axis to major axis spin under the influence of viscous damping and a small flexible appendage constrained to undergo only torsional vibration is investigated. The focus in this paper is on the way in which the dynamics of the liquid and flexible appendage vibration are coupled. The equations of motion are derived and then transformed into a form suitable for the application of Melnikov's method. Melnikov's integral is used to predict the transversal intersections of the stable and unstable manifolds for the perturbed system. An analytical criterion for chaotic motion is derived in terms of the system parameters. This criterion is evaluated for its significance to the design of spacecraft. The dependence of the onset of chaos on quantities such as body shape and magnitude of damping values, fuel fraction and frequency of flexible appendage vibration are investigated.