月面克里普岩成分特征及REE等资源开发利用前景

克里普岩(KREEP)最早发现于Apollo-12样品，后来在所有返月样品中都发现3克里普岩碎片，尤其以Apolio-12和Apolio-14着陆点样品中最多，因其富含元素K1REE和P而被称之为KREEP．克里普岩在月面上的分布极为重要，不但因其对月壳形成期间及形成以后的月球的演化具有重要的意义，而且由于克里普岩中富含REE等重要资源性元素，被认为可能是除钛铁矿外最重要的月球矿产资源储存库．本文在综合已有探测资料和研究成果的基础上，通过克里普岩的化学成分与矿物组成特征，Th在风暴洋区丰度的异常特征，以及克里普岩中Th与REE相关关系的分析，探讨了KREEP岩石在月面上的分布区域，进而对月球REE资源的开发利用前景进行了初步评估．     

基于改进蚁群算法的飞行仿真转台的控制优化

提出了一种用改进蚁群算法优化飞行仿真转台非线性PID控制参数的新策略,借助相遇搜索策略和信息素残留系数的自适应控制思想对基本蚁群算法进行了改进,设计了一种基于改进蚁群算法优化飞行仿真转台非线性PID(NLPID)控制参数的飞行仿真转台系统结构,在对非线性PID控制参数进行优化时采用了时间乘以误差绝对值积分最小性能指标,最后将用改进蚁群算法优化后的控制参数应用于某型高性能飞行仿真转台。实验表明,采用改进蚁群算法优化非线性PID控制参数的飞行仿真转台系统可从带噪声的输入信号中合理地提取出微分信号,并且对噪声具有很强的滤波作用,整个系统响应速度快,并具有较强的鲁棒性。     

基于改进蚁群算法的月面机器人的路径规划及虚拟仿真

针对月面机器人在复杂地形下的路径规划问题,提出了一种改进的蚁群算法。算法构建了栅格化地形图,基于人工势场法改进了蚁群算法的启发函数,加快了算法收敛速度;引入空间信息素划分方法,提高了蚁群在最短路径附近区域的搜索能力;实验证明,改进后的蚁群算法,路径规划成功率显著提高,收敛速度加快。在算法规划出月面机器人的最短路径后,采用虚拟仿真技术,基于unity3D构建虚拟月面环境和月球车,直观地展示了月面机器人在月面环境下的路径规划效果。     

应用于传感器网络覆盖问题的能量有效性启发式机制

提出了一种解决无线传感器网络覆盖问题的分布式启发式机制。该机制在节能前提下,得到优化的目标覆盖集合,以实现对目标监控区域的完全覆盖,并通过对其中重点目标集合的冗余覆盖来满足对重点目标集的可靠监控。同时,该目标覆盖集合与数据汇集点在通信结构上保持连通性。本文采用了改进的蚁群优化算法（最大最小蚁群混合算法）来实现上述启发式机制。通过构造新颖的启发式因子,人工蚂蚁能够由局域信息感知传感器网络的能量状况和覆盖能力,从而自适应地建立具备通信连通性的数据汇集路径。此外,将信息素浓度调节因子和评价函数引入了信息素更新规则的设计,使得蚁群在扩大搜索范围的基础上,提高了解的质量,且避免了求解过程陷入局部最优。算法的输出为能量有效的优化解集,具备较长生命周期,能够在保证与数据汇集点可靠连通的同时实现对目标区域的有效覆盖。     

Depth dependency of neutron density produced by cosmic rays in the lunar subsurface

Depth dependency of neutrons produced by cosmic rays (CRs) in the lunar subsurface was estimated using the three-dimensional Monte Carlo particle and heavy ion transport simulation code, PHITS, incorporating the latest high energy nuclear data, JENDL/HE-2007. The PHITS simulations of equilibrium neutron density profiles in the lunar subsurface were compared with the measurement by Apollo 17 Lunar Neutron Probe Experiment (LNPE). Our calculations reproduced the LNPE data except for the 350–400 mg/cm² region under the improved condition using the CR spectra model based on the latest observations, well-tested nuclear interaction models with systematic cross section data, and JENDL/HE-2007.     

数字化城市交通向导仿真的蚁群优化算法

以求解旅行商问题的蚁群算法为基础,充分考虑交通向导最佳路径的具体要求,对算法的选择机制、更新机制以及协调机制作进一步改进,引入自适应的转移策略,并融入节约法,以克服基本蚁群算法计算时间长、易出现停滞等缺陷。以湖北荆门地区车辆选择路径为研究对象,采用蚁群优化算法建立了车辆最佳路径的模型,并对其进行了仿真分析。仿真实验结果表明,优化算法比基本蚁群算法的路径更优,寻路时间更短。     

Coupling of earth’s magnetosphere,solar wind and lunar plasma environment

The Moon does not have significant atmosphere and magnetic field. So it was considered like a passive absorber of incoming plasma. The latest observation revealed that the significant deflected proton fluxes exist over magnetic anomalies at lunar surface. Such deflection implies that the magnetic anomalies may act as magnetosphere-like obstacles (mini-magnetospheres), modifying the upstream plasma.     

SNR periodical variation of Chang'E-3 spacecraft orbiting the Moon

Chang'E-3 spacecraft was orbiting the Moon from December 6–14, 2013, and very long baseline interferometry(VLBI) observations were performed to improve the accuracy of its orbit determination. In the process of recording VLBI raw data, 2 bits quantization was implemented.Interesting phenomenon was that signal-to-noise ratio(SNR) of each VLBI station experienced periodical change and had large variation on amplitude while in the Moon's orbit, whereas SNR kept in a stable level after Chang'E-3 landed on the Moon. Influence of varying elevation angle on SNR was analyzed and compensation of 2 bits quantization harmonics to SNR calculation was investigated. Most importantly, telescope system noise temperature increase caused by the Moon was computed along the time of Chang'E-3 orbiting the Moon, and well matched SNR changing trend in terms of correlation coefficients.     

Libration point orbit rendezvous using PWPF modulated terminal sliding mode control

The near-range rendezvous problem of two libration point orbit spacecraft in the Earth–Moon system is studied using the terminal sliding mode control which enables a time-fixed process with the flight time prescribed a priori. The underlying dynamics are the full nonlinear equations of motion for a complete Solar System model. For practical purposes, two means of pulse-width pulse-frequency (PWPF) modulation are employed to realize the theoretical continuous control with a series of thrust pulses. Extensive simulations with major errors taken into account show that the sliding mode controller can successfully guide the chaser to a given staging node with the final position and velocity errors, on average, lower than 20 m and 1 mm/s, respectively. Compared with the glideslope guidance previously studied, the proposed approach outperforms the former by saving approximately 50–60% of total delta-v.     

基于改进蚁群算法的改航路径规划研究

当航班遇到恶劣天气或者飞行冲突时,可以采取航班改航策略为需要改航的航班规划出合适的飞行路径。采用栅格法对环境进行建模并且对传统蚁群算法进行改进。首先,在转移概率的计算上加入危险天气的影响等级;其次,在节点选择上采用贝叶斯思想,通过后验概率对候选节点进行评估;最后,通过在短时间内信息素的增量上的差别来增大较优路径和其他路径之间的信息素量的差距,引导算法收敛到最优路径,同时加快算法的收敛速度。经算例分析证明了方法的有效性和可行性。