双余度飞行显示控制计算机的设计与实现

飞行显示控制计算机是飞行员高效、直观地获取所需信息或发送控制命令的操作平台,其任务可靠性对飞机飞行安全至关重要,一旦失效将会造成系统部分或全部功能丧失,尽管不会直接危及飞行员人机安全,但会严重影响飞行和作战任务的完成。因而本设计采用了双余度设计方法,有效提高了任务可靠性、降低了失效风险,具备一定的工程实用价值。     

反潜直升机武器挂载方案研究与仿真

反潜直升机在任务规划期间,优化武器挂载方案是提高反潜直升机搜攻潜效能的有效途径.通过建立反潜直升机搜攻潜效能数学模型,分析任务执行期间可能的作战模式和它们的效率及代价,给出不同预设搜潜模式下的典型武器挂载方案,辅助任务规划人员进行决策.仿真表明,所提出的武器挂载规划方法具备经验法简单实用的优点,同时还量化了搜索时间、搜索面积、搜索和攻击概率等指标,方便任务规划人员进行决策.     

交会与拦截动力学内涵探讨

交会与拦截是动力学中的两个典型应用场景,都是研究空间中两个运动质点的精确相对运动的问题。传统的课程教学忽视了两者的内在联系,教学内容存在交叉重复、不统一等问题,本文以理论力学中点的复合运动为基础,从动力学模型与制导律两个维度对交会和拦截的内涵关系进行深度挖掘和阐释,打通两类相对运动之间的壁垒,建立起教学内容的有效链接,探索了航天动力学教学的新框架,有助于提升教学效率。

     

面向任务代价差异的移动群智感知激励模型

针对感知任务参与者数量不足和提供数据质量不高的问题,该文提出一种面向任务代价差异的移动群智感知激励模型。首先,利用模糊推理方法分析数据量、环境条件及设备消耗对任务代价的影响,将感知任务按照代价差异划分为不同等级,同时为请求者制定预算并给予参与者合适的报酬。其次,通过信誉度评估和参与者优选将感知任务分配给更合适的参与者完成感知任务并上传感知数据。最后,对参与者上传感知数据评估,更新参与者信誉度,并根据参与者完成感知任务的代价等级支付相应报酬。基于真实数据集的仿真实验结果表明,该模型能够利用各个模块间的相互影响,有效招募更多的用户参与感知任务并促进参与者上传高质量的感知数据。     

载人登月轨道研究综述

21世纪初叶,美国星座计划、欧洲曙光计划以及中国嫦娥工程计划的相继提出,彻底拉开了人类重返外太空的序幕,载人登月也被赋予了全新的涵义和使命.探测内容的多样化,轨道设计的复杂精细化,宇航员安全保障的突出化,进一步加大了载人登月工程任务设计的复杂度与难度.文中分别从载人登月轨道整体、地月转移轨道、空间交会对接以及全月面到达这4个方向介绍载人登月当前研究进展与现状,并列举了各研究领域的相关热点问题.基于对上述研究现状的分析,尝试展望了该研究领域未来的发展趋势.     

Introduction of plastic encapsulated devices in systems operating under severe temperature conditions

In this paper, we describe the evolution of the selection, qualification and implementation methods used to validate the introduction of plastic SMD's into electrical equipment submitted to extreme environmental conditions:The first introduction phase was addressing equipment operating up to 125°C. The selection process was intentionally kept to minimum with emphasis on qualification through mission profile at equipment level. The results in terms of cost, performance, reliability and field feedback experience were extremely positive.The second phase was initiated for operating conditions as high as 175 °C environmental temperature. The selection process of plastic components operating at such extreme conditions, includes a full qualification through mission profile at component level. The experiments using vehicle test boards led to numerous electrical failures originated by a unique failure mechanism: delamination.In consequence, the selection process is being reviewed: a short-test for capability will be run with emphasis on initial behavior versus delamination.Expected benefits are

reduction of overall qualification costs through elimination of complete qualification with mission profile at component level.

faster availability to designers.

     

Linearized impulsive rendezvous problem

The solution of the problem of impulsive minimization of a weighted sum of characteristic velocities of a spacecraft subject to linear equations of motion is presented without the use of calculus of variations or optimal control theory. The geometric structure of the set of boundary points associated with an optimal primer vector is found to be a simplex composed of convex conical sets. Eachk-dimensional open face of the simplex consists of boundary points having nondegeneratek-impulse solutions. This geometric structure leads to a simple proof that at mostn-impulses are required to solve a problem inn-dimensional space. This work is applied to the problem of planar rendezvous of a spacecraft with a satellite in Keplerian orbit using the Tschauner-Hempel equations of motion, with special emphasis on four-impulse solutions. Primer vectors representing four-impulse solutions are sought out and found for elliptical orbits, but none were found for orbits of higher eccentricity. For highly eccentric elliptical orbits, degenerate fiveimpulse solutions were found. In this situation, computer simulations reveal vastly different optimal trajectories having identical boundary conditions and cost.     

Optimal impulsive space trajectories based on linear equations

The problem of minimizing the total characteristic velocity of a spacecraft having linear equations of motion and finitely many instantaneous impulses that result in jump discontinuities in velocity is considered. Fixed time and fixed end conditions are assumed. This formulation is flexible enough to allow some of the impulses to be specifieda priori by the mission planner. Necessary and sufficient conditions for solution of this problem are found without using specialized results from control theory or optimization theory. Solution of the two-point boundary-value problem is reduced to a problem of solving a specific set of equations. If the times of the impulses are specified, these equations are at most quadratic. Although this work is restricted to linear equations, there are situations where it has potential application. Some examples are the computation of the velocity increments of a spacecraft near a real or fictitious satellite or space station in a circular or more general Keplerian orbit. Another example is the computation of maneuvers of a spacecraft near a libration point in the restricted three-body problem.This project was supported by the 1988 NASA/ASEE Faculty Fellowship Program at the California Institute of Technology and the Jet Propulsion Laboratory. The work was performed in the Advanced Projects Group, Section 312, Jet Propulsion Laboratory, Pasadena, California.     

Development of a temperature gradient focusing method for in situ extraterrestrial biomarker analysis

Scanning temperature gradient focusing (TGF) is a recently described technique for the simultaneous concentration and separation of charged analytes. It allows for high analyte peak capacities and low LODs in microcolumn electrophoretic separations. In this paper, we present the application of scanning TGF for chiral separations of amino acids. Using a mixture of seven carboxyfluorescein succinimidyl ester-labeled amino acids (including five chiral amino acids) which constitute the Mars7 standard, we show that scanning TGF is a very simple and efficient method for chiral separations. The modulation of TGF separation parameters (temperature window, pressure scan rate, temperature range, and chiral selector concentration) allows optimization of peak efficiencies and analyte resolutions. The use of hydroxypropyl-beta-CD at low concentration (1-5 mmol/L) as a chiral selector, with an appropriate pressure scan rate ( -0.25 Pa/s) and with a low temperature range (3-25 degrees C over 1 cm) provided high resolution between enantiomers (Rs >1.5 for each pair of enantiomers) using a short, 4 cm long capillary. With these new results, the scanning TGF method appears to be a viable method for in situ trace biomarker analysis for future missions to Mars or other solar system bodies.     

探月飞行器效能评估研究与实践

航天器飞行效能评估是整器级测试验证以及在轨飞行结果评价中不可或缺的重要环节,针对我国探月三期月地高速再入返回飞行试验,提出了一种基于任务剖面的航天器飞行效能评估方案;提取7个任务剖面、17个约束条件,建立面向月地再入返回过程的指标评估体系;通过定量、定性指标量化计算、权重系数层次分析法计算各任务剖面的能力度量值,解决了系统目标完成能力不易定量描述的难题,实现了对月地转移段、大气层外自由飞行段、再入段、跃出段等过程自主飞行能力的科学定量评估,对后续月球无人采样返回、火星探测等探测器系统的效能评估具有一定参考意义;该方法已应用于月地高速再入返回飞行器系统。