Implementation of tactical maneuvers with maneuver libraries

This study creates and combines the general maneuver libraries for fixed-wing aircraft to implement tactical maneuvers. First, the generalized maneuver libraries are established by analyzing the characteristics of tactical maneuvers required in battlefields. The 7th order polynomial is applied to both the creation of the maneuver libraries and the generation of the trajectories or flight paths for modal inputs. To track the desired trajectory, we design the Attitude Command Attitude Hold (ACAH) system and the Rate Command Rate Hold (RCRH) system using Model Following Controller (MFC). Moreover, the Line-of-Sight (LOS) guidance law is designed. In particular, the CONDUIT® is employed to optimize the gains so that the control systems meet the aircraft Handling Qualities (HQ) criteria. Finally, flight simulations are performed for the longitudinal loop, immelmann-turn, and climb-slalom-descent maneuvers to verify that tactical aggressive maneuvers are realizable via the combination of maneuver libraries. This study can contribute to the development of flight techniques for aircraft tactical maneuvers and to the revision of air force operational manuals.     

Topology optimization in lightweight design of a 3D-printed flapping-wing micro aerial vehicle

Topology optimization is an effective method to obtain a lightweight structure that meets the requirements of structural strength. Whether the optimization results meet the actual needs mainly depends on the accuracy of the material properties and the boundary conditions, especially for a tiny Flapping-wing Micro Aerial Vehicle (FMAV) transmission system manufactured by 3D printing. In this paper, experimental and numerical computation efforts were undertaken to gain a reliable topology optimization method for the bottom of the transmission system. First, the constitutive behavior of the ultraviolet (UV) curable resin used in fabrication was evaluated. Second, a numerical computation model describing further verified via experiments. Topology optimization modeling considering nonlinear factors, e.g. contact, friction and collision, was presented, and the optimization results were verified by both dynamic simulation and experiments. Finally, detailed discussions on different load cases and constraints were presented to clarify their effect on the optimization. Our methods and results presented in this paper may shed light on the lightweight design of a FMAV.     

部署retro-GEO巡视器的月球借力飞行轨道分析

retro-GEO是指逆行（retrograde）地球静止轨道（geostationary Earth orbit, GEO），该轨道与GEO轨道高度相同或相近，但倾角为180°，安装在retro-GEO卫星上的巡视器可每12h对GEO带空间资产附近碎片环境安全预警。直接西向发射retro-GEO卫星存在地面测控和发射能耗较大的困难。基于平面四体模型，为降低设计变量敏感性，以近月点参数为设计变量，建立了部署retro-GEO巡视器的月球借力飞行轨道设计模型，利用轨道动力学模型延拓策略，得到该类轨道绕月后返回地球飞行时长只能约为114.79h，该结论可用于求解该类轨道高精度轨道动力学模型解。     

An improved numerical method for constructing Halo/Lissajous orbits in a full solar system model

An improved numerical method that can construct Halo/Lissajous orbits in the vicinity of collinear libration points in a full solar system model is investigated. A full solar system gravitational model in the geocentric rotating coordinate system with a clear presentation of the angular velocity relative to the inertial coordinate system is proposed. An alternative way to determine patch points in the multiple shooting method is provided based on a dynamical analysis with Poincare′sections. By employing the new patch points and sequential quadratic programming, Halo orbits for L_1, L_2, and L_3 points as well as Lissajous orbits for L_1 and L_2 points in the EarthMoon system are generated with the proposed full solar system gravitational model to verify the effectiveness of the proposed method.     

不同密度弹丸对水冰的超高速撞击成坑实验

为了研究冰冻天体表面撞击坑的形成与演化，开展了水冰的超高速撞击成坑实验。使用二级轻气炮发射1.0 mm直径的球形弹丸，以3 km/s、5 km/s和7 km/s速度对圆柱状冰块进行撞击。弹丸材料包括聚碳酸酯和不锈钢两种，冰块温度为253 K。实验观察到了不同弹丸和不同速度条件下，冰块中撞击坑的形貌特征。对撞击坑直径、深度和剖面形状进行了测量，并与文献中铝弹丸对水冰的撞击坑进行了比较分析。获得了水冰撞击坑特征随撞击参数的变化规律，结果表明：撞击坑直径和深度的主导机制不同，坑深主要由弹丸侵彻作用形成，而坑径主要由冰块的剥落所致；坑深比坑径具有更强的对于弹丸密度的依赖性，高密度弹丸撞击坑直径具有比低密度弹丸更强的对于撞击速度的依赖性；撞击坑体积与撞击能量成正比，高密度弹丸形成的撞击坑直径表现出“能量缩比”行为，而低密度弹丸形成的撞击坑直径表现出“动量缩比”行为。     

双模块下颌式内转进气道/圆锥前体一体化布局研究

为实现三维内转进气道的内收缩流场与圆锥前体的外压缩流场的良好匹配，提出了一种双模块下颌式内转进气道/圆锥前体(Double-modules Chin Inward-turning Inlet and Conical Forebody，DCII/CF)一体化设计方法，获得一种新颖的双发并置、侧向安装的DCII/CF一体化布局。针对该布局形式，开展了DCII/CF一体化构型与传统的单模块内转进气道/圆锥前体(Single-module Inward-turning Inlet and Conical Forebody，SII/CF)一体化构型的数值对比研究。结果表明：DCII/CF一体化布局不仅为内转进气道提供了优秀的前体附面层排移效果，还有效避免了传统SII/CF布局中前体附面层与进气道内部流场之间的相互干扰。在Ma∞=6.0设计状态，DCII/CF一体化布局的进气道总压恢复系数相较传统的SII/CF布局有了显著提高，从0.403提高至0.482；但由于前体附面层的排移，该布局的捕获流量略有降低， SII/CF的流量系数为0.956，该布局则为0.917。而在非设计状态，该布局形式同样具备较好的总压恢复性能，在Ma∞=5.0与Ma∞=4.0的总压恢复系数分别达到了0.586和0.682，明显高于SII/CF的总压恢复系数0.507和0.619。     

电铸镍Wolter I型光学系统制造技术发展综述

摘要： 为满足未来脉冲星导航和空间天文观测任务对X射线望远镜的载荷需求，Wolter I光学系统的研制正逐渐成为新的研究热点，电铸镍方案是当前国内外X射线光学系统镜筒制造的主要技术方案.文章对电铸镍X射线光学系统制造工艺、国内外研制现状、未来应用需求进行了介绍和整理，梳理了电铸镍X射线光学系统研制遇到的关键技术和难点，提出了后续研究发展建议，以促进中国在 X射线脉冲星自主导航、空间探测领域的快速发展.     

反推装置对翼身融合分布式推进系统气动性能影响数值模拟

为了研究新型反推装置对翼身融合分布式推进系统气动性能的影响,将机身简化为二维模型,利用数值模拟的手段来研究攻角、反推开度,以及风扇打开或关闭对飞行参数的影响,为翼身融合分布式推进系统的反推装置设计提供初步的意见和建议。结果显示:反推闭合和风扇打开之后该机型的升力系数和俯仰力矩系数都会有较大增加;随着反推开度的增加,升力系数和俯仰力矩系数也随之增加;来流攻角对翼身融合分布式推进系统的气动性能也有较大影响。      

异构无人系统协同作战关键技术综述

针对异构无人系统的规模、异构性强弱，对异构无人系统进行了分类，引入了异构无人系统协同作战班组的概念以及应用设想，并通过城市环境中异构无人系统协同作战问题为牵引，提出了异构无人系统协同作战面临的挑战与解决思路，在此基础之上，从异构无人系统协同控制架构、协同任务规划、智能交互、目标感知、环境感知等主要方面对异构无人系统协同作战的关键技术进行了分析，最后对异构无人系统协同作战目前的研究进展与挑战进行了总结。     

某机载探测系统自主回收技术的实现

针对某机载探测系统探头回收自动化程度低的问题，提出了在无需操作员干预情况下实现探头自主回收的技术方法。采用了先进的控制算法，将缆位角与探头、缆长进行结合并引入了绞车控制系统，使绞车对探头的回收速度及缆长可进行实时调整，并给出了3种不同缆位角摆动条件下缆长与探头回收速度的控制曲线关系。研发了自主回收装置，设计了能够实现自主回收功能的探头回收机构。实验验证表明：在无需人为干预的条件下，在缆位控制系统及自主回收机构的配合下，系统实现了对探头快速、安全的回收。