Spatial approaches to moons from resonance relative to invariant manifolds

In this study, the final approach to a moon or other body from resonance is explored and compared to the invariant manifolds of unstable periodic orbits. It is shown that the stable manifolds of planar Lyapunov orbits can act as a guide for the periods or resonances that are required for the final approach in both the planar and spatial problems. Previously developed techniques for the planar problem are expanded for use with resonances and used for comparison with trajectories approaching a moon from these resonances. A similar technique is then used for exploring the relationship of invariant manifolds to approach trajectories in the spatial problem. It is shown that the invariant manifolds of unstable periodic orbits provide insight into the trajectory design, and they can be used as a guide to the more direct approach trajectories.     

增强FMS柔性的关键技术研究

柔性制造技术是现代制造业广泛采用的一种先进的制造技术。实现生产柔性是引进柔性制造技术的根本目的。ＦＭＳ是柔性制造技术应用的典型模式。     

组织管理的系统思维

系统是由相互关联的元素组成的整体。系统思维(Systems Thinking)是一种以整体观点观察事物的方式。基于工程原理和法则的定量化模型方法在管理领域的应用,因为人的动机和行为的复杂性而受到了限制。综合集成是具有系统思维的管理者对现实问题的不同诠释,是认识和解决管理复杂性问题的有效方法。     

复杂可修系统效能中可信度矩阵的构造方法

复杂可修系统可信度建模对保证效能的定量分析至关重要.本文在考虑不同维修状况的基础上,着重对不同任务剖面内相应任务阶段中武器装备可信度进行了深入的定量分析和综合,进而构造出武器装备的可信度矩阵,用于武器装备的效能分析;文中以某地面车辆为例,进一步论证了武器装备可信度矩阵的工程含义,旨在为合理确定一大类武器装备的效能和可信度指标提供理论依据.     

A formal approach using SysML for capturing functional requirements in avionics domain

In this work, a Model-Based Systems Engineering approach based on SysML is proposed. This approach is used for the capture and the definition of functional requirements in avionics domain. The motivation of this work is triple: guide the capture of functional requirements, validate these functional requirements through functional simulation, and verify efficiently the consistency of these functional requirements. The proposed approach is decomposed into several steps that are detailed to go from conceptual model of avionics domain to a formal functional model that can be simulated in its operating context. To achieve this work, a subset of SysML has been used as an intermediate modelling language to ensure progressive transformation that can be understood and agreed by system stakeholders. Formal concepts are introduced to ensure theoretical consistency of the approach. In addition, transformation rules are defined and the mappings between concepts of ARP4754A civil aircraft guidelines and SysML are formalized through meta-model. The resulting formalization enables engineers to perform functional simulation of the top-level functional architecture extracted from operational scenarios. Finally, the approach has been tested on an industrial avionics system called the Onboard Maintenance System.     

基于模型的载人航天器研制方法研究与实践

载人航天器具有系统规模大、技术难度高、单件小批量、无法通过多次飞行持续完善设计、可靠性要求高等特点。当前载人航天器研制中仍存在着参数化和模型化程度不高、基于模型的系统综合仿真验证不足、研制各环节缺乏数字化集成等问题，传统基于文本的系统工程方法已无法满足研制需求，亟需采用基于模型的系统工程方法。本文针对载人航天器的研制现状和应用需求，提出了面向载人航天器全生命周期的模型体系，定义了需求模型、功能模型、产品模型、工程模型、制造模型、实做模型等六类模型，提出了基于模型的研制流程，包含系统设计闭环验证、产品设计闭环验证、实做产品闭环验证3个验证环节，并深入探索了各研制环节中不同模型间的传递与关联关系。以某型号载人航天器为应用基础，系统地验证了提出的方法。     

Dynamics of a spacecraft and normalization around Lagrangian points in the Neptune–Triton system

The problem of a spacecraft orbiting the Neptune–Triton system is presented. The new ingredients in this restricted three body problem are the Neptune oblateness and the high inclined and retrograde motion of Triton. First we present some interesting simulations showing the role played by the oblateness on a Neptune’s satellite, disturbed by Triton. We also give an extensive numerical exploration in the case when the spacecraft orbits Triton, considering Sun, Neptune and its planetary oblateness as disturbers. In the plane a × I (a = semi-major axis, I = inclination), we give a plot of the stable regions where the massless body can survive for thousand of years. Retrograde and direct orbits were considered and as usual, the region of stability is much more significant for the case of direct orbit of the spacecraft (Triton’s orbit is retrograde). Next we explore the dynamics in a vicinity of the Lagrangian points. The Birkhoff normalization is constructed around L₂, followed by its reduction to the center manifold. In this reduced dynamics, a convenient Poincaré section shows the interplay of the Lyapunov and halo periodic orbits, Lissajous and quasi-halo tori as well as the stable and unstable manifolds of the planar Lyapunov orbit. To show the effect of the oblateness, the planar Lyapunov family emanating from the Lagrangian points and three-dimensional halo orbits are obtained by the numerical continuation method.     

Integration of lessons from recent research for “Earth to Mars” life support systems

Development of reliable and robust strategies for long-term life support for planetary exploration must be built from real-time experimentation to verify and improve system components. Also critical is incorporating a range of viable options to handle potential short-term life system imbalances. This paper revisits some of the conceptual framework for a Mars base prototype which has been developed by the authors along with others previously advanced (“Mars on Earth^®”) in the light of three years of experimentation in the Laboratory Biosphere, further investigation of system alternatives and the advent of other innovative engineering and agri-ecosystem approaches. Several experiments with candidate space agriculture crops have demonstrated the higher productivity possible with elevated light levels and improved environmental controls. For example, crops of sweet potatoes exceeded original Mars base prototype projections by an average of 46% (53% for best crop) ultradwarf (Apogee) wheat by 9% (23% for best crop), pinto bean by 13% (31% for best crop). These production levels, although they may be increased with further optimization of lighting regimes, environmental parameters, crop density etc. offer evidence that a soil-based system can be as productive as the hydroponic systems which have dominated space life support scenarios and research. But soil also offers distinct advantages: the capability to be created on the Moon or Mars using in situ space resources, reduces long-term reliance on consumables and imported resources, and more readily recycling and incorporating crew and crop waste products. In addition, a living soil contains a complex microbial ecosystem which helps prevent the buildup of trace gases or compounds, and thus assist with air and water purification. The atmospheric dynamics of these crops were studied in the Laboratory Biosphere adding to the database necessary for managing the mixed stands of crops essential for supplying a nutritionally adequate diet in space. This paper explores some of the challenges of small bioregenerative life support: air-sealing and facility architecture/design, balance of short-term variations of carbon dioxide and oxygen through staggered plantings, options for additional atmospheric buffers and sinks, lighting/energy efficiency engineering, crop and waste product recycling approaches, and human factor considerations in the design and operation of a Mars base. An “Earth to Mars” project, forging the ability to live sustainably in space (as on Earth) requires continued research and testing of these components and integrated subsystems; and developing a step-by-step learning process.     

基于软件工程思想方法的CAI课件开发

介绍了软件工程思想方法，运用软件工程思想方法基于瀑布模型分析了CAI课件开发过程，实践创作开发了基于Web的多媒体《概率论与数理统计》CAI课件。     

CAD技术及其在卫星工程中的应用

CAD 技术作为一种高效率、高质量、高精度的设计技术,正在包括航天技术在内的多个领域中广泛应用,发挥其效益。尤其是在机械(MCAD)与电子(ECAD)两方面的应用,更是令人瞩目。本文就CAD 技术的范畸、功能、组成、主要技术等并结合卫星研制的具体应用前景,作一介绍,目的在于推动CAD技术的开展,并为CAD/CAM 一体化做好思想准备。