面向增材制造的飞行器结构优化设计关键问题

围绕飞行器复杂结构整体构型研制的高性能、轻量化苛刻需求,着重介绍了面向增材制造的结构优化设计面临的系列关键问题以及相关研究成果。分别从面向增材制造的结构多承载环节整体优化建模与性能分析、整体结构多学科性能与功能综合设计方法、跨尺度结构-微结构性能表征与尺度效应的影响机理,以及增材制造工艺对整体结构件性能的影响机理和制造工艺约束4个方面,阐述如何从结构力学与工艺力学角度科学实现最优性能设计与先进增材制造技术的完美匹配与融合。     

基于距离信息的行人协同导航研究

针对行人在室内导航中GPS信息无法获取以及纯惯导解算结果发散严重的问题,提出了通过协同导航的方式提高行人室内导航精度的方法.利用行人间的相对距离约束关系,抑制纯惯导解算结果的发散.详细推导了行人协同导航的模型,采用信息滤波的方法解算导航结果,并在理论推导中发现信息滤波更加适合行人协同导航的工程实践.设计了一种使用微型惯性测量器和超宽带测距设备的行人协同导航系统,进行实际效果验证.通过数据采集与处理,将行人导航轨迹图输出,分析协同导航以及单独导航的误差,验证协同导航的有效性.实验结果表明,协同导航与单独导航相比,对导航轨迹和导航误差有更好的修正效果.     

基于NHDO的机动目标拦截攻击角度约束导引律

为了精确控制导弹在有限时间内以期望攻击角度拦截机动目标,采用将导弹自动驾驶仪简化为惯性环节的方法,结合终端滑模控制理论设计了一种带攻击角度约束的有限时间收敛制导律。为了滤除视线角速率噪声,提出一种非线性跟踪微分滤波器对噪声进行滤波,建立了考虑滤波的制导系统状态方程,基于此方程设计非齐次干扰观测器,用于目标机动不确定项的估计补偿。仿真结果表明,所设计的制导律能达到对视线角速率有效滤波,对目标机动状态精确估计的目的,克服系统动态延迟对制导精度的不利影响,满足攻击角度和制导精度的双重要求。     

卫星能源约束检查模型改进及仿真

卫星能源约束检查模型对卫星任务规划有重要参考作用,可防止因能源不足而导致卫星故障或任务不能顺利完成。现有的能源约束检查模型存在部分问题:人为设定计算初始值,导致计算不准确;能源约束检查不通过时未给出符合能源约束的任务调整建议,导致任务不能快速调整;未对计算误差进行校正,导致误差积累。对此,提出了一种改进的能源约束检查模型,在原有模型中加入能源数据库对卫星运行的能源数据进行记录,从而准确获取初始值,并在模型中加入任务调整和遥测校正功能。该模型可实现能源约束计算自动管理及任务自动调整功能,缩短任务规划周期,提升紧急任务的执行效率。对改进的模型进行仿真,结果表明:模型预测结果与预期值相符,任务调整和能源校正功能实现良好,能实际应用到运控系统中进行规划任务能源约束检查和能源管理。     

应用约束条件快速解算整周模糊度

ＧＰＳ载波相位测量用于解算载体的航向和姿态时必需解决的问题之一就是整周模糊度的确定。近年来提出了多种模糊度的解算法方法,但对ＧＰＳ航姿系统来说,若能利用固有的约束条件则会使模糊度问题变得简单且快速有效。在详细分析了几种约束条件的基础上,文中探讨了如何合理 这些约束条件来减小模糊度的搜索范围,以加快模糊度的解算速度,并对检验方法作了改进。通过仿真结果对文中方法进行了检验。     

Finite-time composite guidance law with input constraint and dynamics compensation

Guidance laws are proposed for a near space interceptor with on–off type thrust as output. The target-interceptor engagement kinematics is integrated with the first-order dynamics of thruster to design guidance laws. The bang-bang type guidance law with linear sliding mode is proposed to deal with thruster dynamics, and the sufficient condition for finite time convergence is rigorously proved based on the finite-time convergence theory. According to the sufficient condition, a sliding mode guidance law with hysteresis-band switching is introduced to reduce the switching frequency of thruster. Then two guidance laws are combined into a composite guidance law to improve the guidance performance. Simulation results show that the line-of-sight angular rate can converge to a neighborhood of the equilibrium point before the final time of the guidance process, and the composite guidance law has better performance than typical guidance laws.     

关于约束分类问题的研究

约束条件的分类对于简化数学规划问题的求解具有重要意义，对于凸函数ｇｉ（ｘ）（ｉ＝１，２，…，ｎ）给出了约束ｇｉ（ｘ）≤０是必要约束或多余约束的充要条件，对于一般约束，定义了约束相关矩阵，给出了约束是必要的或多余的充要条件，对相对多余约束给出了分类。     

FUSELAGE STRUCTURAL OPTIMIZATION WITH MSC／MOD PRE－PROCESSING AND MSC／PAL2 POST－PROCESSING

ＦＵＳＥＬＡＧＥＳＴＲＵＣＴＵＲＡＬＯＰＴＩＭＩＺＡＴＩＯＮＷＩＴＨＭＳＣ／ＭＯＤＰＲＥ－ＰＲＯＣＥＳＳＩＮＧＡＮＤＭＳＣ／ＰＡＬ２ＰＯＳＴ－ＰＲＯＣＥＳＳＩＮＧ￥ＣｈｅｎＭｕｌａｎ（ＲｅｓｅａｒｈＩｎｓｔｉｔｕｔｅｏｆＰｉｌｏｔｌｅｓｓＡｉｒｃｒａ...     

Plastic wrinkling model and characteristics of shear enforced Ti-alloy thin-walled tubes under combination die constraints and differential temperature fields

Plastic wrinkling predictions and shear enforced wrinkling characteristics of Ti-alloy thin-walled tubes under combination die constraints have become key problems urgently in need of solutions in order to improve forming quality in their shear bending processes under differential temperature fields. To address this, a wrinkling wave function was developed by considering their shear bend deformation characteristics. Based on this wave function and the thin shell theory, an energy prediction model for this type of wrinkling was established. This model enables considera-tion of the effects of shear deformation zone ranges, material parameters, loading modes, and fric-tion coefficients between tube and dies on the minimum wrinkling energy. Tube wrinkling sensitive zones (WSZs) can be revealed by combining this wrinkling prediction model with a thermal-mechanical coupled finite element model for simulating these bending processes. The reliability of this wrinkling prediction model was verified, and an investigation into the tube wrinkling char-acteristics was carried out based on the experimental conditions. This found that the WSZs are located on either a single side or both sides of the maximum shear stress zone. When the friction coefficients between the tube and the various dies coincide, the WSZs are located on both sides. The larger the value of the tube inner corner radius and/or the smaller the value of the outer corner radius, the smaller the wrinkling probability. With an increase in the value of the moving die dis-placement, the wrinkling probability increases at first, and then decreases.     

基于最临界约束准则法的机翼主承力结构优化

利用最临界约束准则法对某型飞机机翼主承力结构在强度，位移，扭转角，稳定性和尺寸约束下，以最小重量为目标函数进行了优化，并在实际操作过程中依据机翼结构的复杂性对最临界约束准则法做了相应的修改。结果表明，应用最临界约束准则法进行机翼结构优化时，效率较高，机翼结构重量稳定下降，优化效果明显。