机器人在轨构建空间桁架结构的装配序列规划方法

针对机器人在轨构建空间桁架结构的装配序列规划问题,提出一种可同时求解装配单元装配序列与机器人运动的序列规划方法.首先设计了装配机器人并建立了动力学模型;其次,对机器人在整个装配过程中的运动进行了分类并分别给出了规划与控制方法;然后,建立了装配序列规划的评价指标并采用离散粒子群算法求解.最后,以常用空间桁架结构为例,通过...     

月面巡视探测器太阳帆板热电耦合仿真计算

文章建立了月面巡视探测器太阳帆板热电耦合计算模型,制定了太阳帆板的对日定向方案和输出电能分配方案,通过数值模拟获得了月面白昼期间太阳帆板的温度及电能输出,分析了太阳帆板背面包覆隔热材料前后及帆板是否对日定向等方案的计算结果。计算表明,当帆板不对日定向时其背面包覆隔热材料对其温度场及电能输出无明显影响,对日定向时帆板温度随时间的分布规律发生了明显改变,此时帆板背面包覆隔热材料使其温度明显上升,但帆板顶面与背面的温差减小。     

Fault detection and isolation in GPS receiver autonomous integrity monitoring based on chaos particle swarm optimization-particle filter algorithm

The receiver autonomous integrity monitoring (RAIM) is one of the most important parts in an avionic navigation system. Two problems need to be addressed to improve this system, namely, the degeneracy phenomenon and lack of samples for the standard particle filter (PF). However, the number of samples cannot adequately express the real distribution of the probability density function (i.e., sample impoverishment). This study presents a GPS receiver autonomous integrity monitoring (RAIM) method based on a chaos particle swarm optimization particle filter (CPSO-PF) algorithm with a log likelihood ratio. The chaos sequence generates a set of chaotic variables, which are mapped to the interval of optimization variables to improve particle quality. This chaos perturbation overcomes the potential for the search to become trapped in a local optimum in the particle swarm optimization (PSO) algorithm. Test statistics are configured based on a likelihood ratio, and satellite fault detection is then conducted by checking the consistency between the state estimate of the main PF and those of the auxiliary PFs. Based on GPS data, the experimental results demonstrate that the proposed algorithm can effectively detect and isolate satellite faults under conditions of non-Gaussian measurement noise. Moreover, the performance of the proposed novel method is better than that of RAIM based on the PF or PSO-PF algorithm.     

基于缩放实验的Whipple结构撞击特性

针对航天器空间碎片防护问题,基于缩放实验方法,开展了7 km/s以上超高速碰撞仿真研究.建立了单板和Whipple防护结构的仿真模型,并对铝-铝撞击问题和镉-镉撞击问题进行了多工况仿真.通过实验结果与数值仿真的对比,表明了数值仿真技术的正确性,并从仿真角度验证了缩放实验方法的有效性.对缩放实验方法的适用性进行了仿真验证,结果表明该方法对弹丸形状适用性较好,对3～4 km/s以上撞击速度的适用性较好,但对Whipple防护结构后板存在一定误差.分析了Whipple结构后板的失效模式,提出了失效模式的不连续性导致了缩放实验方法的误差.最后通过数值仿真计算了Whipple结构7 km/s以上弹道极限特性,提出了失效模式的不连续性造成了在该速度段弹道极限曲线的分叉现象.     

多媒体卫星通信系统介绍

本文论述了对多媒体卫星通信系统发展的需求及其关键技术，介绍了多媒体卫星通信系统的基本概念，并对西方特别是美国正在计划和设计中的多媒体卫星系统的基本概况做了较详细的介绍。     

激光载波统一系统方案构想

提出了激光载波统一系统的概念,分析了该体制的优劣势,介绍了国外发展现状,给出了激光载波统一系统的技术方案和应用方案构想。     

变幅单频交流信号幅度的同步采集方法

叙述和介绍了采集交流信号的常用方法，指出了常用方法在采集幅度快速变化的交流小信号时存在的缺陷。在此基础上提出了一种新的交流信号同步采集方法，适合于对采样率和采集精度要求较高的场合。