国外巡航导弹用材料及工艺

简要介绍了巡航导弹的结构和技术数据,美国战斧巡航导弹用材料及工艺,以及目前巡航导弹所用材料及工艺的改进。     

硝酸酯增塑聚醚推进剂中PB类助剂的作用机理

为了解PB类功能助剂的作用机理，进行了接触角测试，XPS，SEM和MDA试验，结果认为：通过降低功能助剂自身极性，使之与HMX的表面性能相匹配，改善了HMX在粘合剂中的润湿性，从而改善药浆工艺性能，同时，保持对HMX有强的亲合力，吸附在HMX表面形成界面层，使推进剂保持良好的力学性能，最后提出了PB类助剂的作用机理。     

电波折射误差实时修正方法研究

目前的实时弹道处理过程中,由于获得探空气象数据比较困难,电波折射误差均采用各种简化方法进行计算,因而大气折射误差计算的精度不高,修正效果不佳。针对这种现状,本文提出了基于双指数模型的射线瞄迹法计算大气折射误差。试算结果表明,该方法的计算精度与事后数据处理所采用的电波折射误差修正方法相当,且能够满足实时处理的时间要求。     

空间站伴随卫星的相对运动控制

研究了空间站伴随卫星在绕飞和回收阶段的相对位置与速度控制。基于C-W方程提出了伴随卫星的脉冲控制和滑模-开关控制两种绕飞控制方法,给出了控制模型并进行了比较。另设计了用于伴随卫星回收控制的模糊控制器,给出了模糊控制规则。仿真结果表明:两种绕飞控制法简便易行,适于工程应用。与一般模糊控制方法相比,此控制器利用了航天器自身的动力学特性,可使燃料更省。     

Automatic orbital docking with tumbling target using sliding mode control

The present study aimed to propose translational and rotational control of a chaser spacecraft in the close vicinity docking phase with a target subjected to external disturbances. For this purpose, two sliding mode controls (SMC) are developed to coordinate the relative position and attitude of two spacecraft. The chaser is guided to the tumbling target by the relative position control, approaching in the direction of the target docking port. At the same moment, the relative attitude control coordinates the chaser attitude so that it can be aligned with the target orientation. These control systems regulate the relative translational and rotational velocities to be zero when two spacecraft are docking. The robustness of the closed-loop system in the presence of external disturbances, measurement noises and uncertainties is guaranteed by analyzing and calculating the control gains via the Lyapunov function. The simulations in different scenarios indicated the effectiveness of the controller scheme and precise maneuver regarding the accuracy of docking conditions.     

浅谈城市会议中心水处理系统的改造方案

通过对某城市会议中心用水系统的实际考察，找出了存在的问题，提出了采用“射频式水处理器”对用水系统进行水处理的改造方案，达到既防止系统结垢，又能减少管网腐蚀，达到维持系统安全稳定运行的目的。     

Resistance welding of glass fiber reinforced thermoplastic composite: Experimental investigation and process parameter optimization

The utilization of fiber reinforced thermoplastics (FRTP) is expected to fulfill lightweight demand in mass-produced aerospace products. Facing the unavoidable assembly of FRTP parts, fusion bonding methods such as resistance welding are promising compared with mechanical joint and adhesive bonding. In this paper, a procedure has been brought out to understand the relationship between processing conditions and performance of the FRTP welding joints. The adherends were continuous glass fiber reinforced polypropylene (GF/PP) laminates fabricated by hot-pressing method. The influences of time, current and pressure on the bending strength of the resistance welding joints were investigated. A processing window was drawn based on the optical observation of welded surfaces. The quantitative relationship between process parameters and mechanical property of GF/PP welding joint was established by Response Surface Method (RSM) with high accuracy. It was found that bending strength of GF/PP welding joint was improved by 31% compared with hot-pressing benchmark.     

临近空间高速飞行器抛罩过程的动网格方法对比

飞行器抛罩是一个复杂的动力学、流体力学耦合问题,涉及六自由度运动方程与N-S方程的耦合求解,其中动网格非定常计算是关键技术。针对二维临近空间高速飞行器,将耦合过程简化为匀速旋转抛罩,对比分析了光顺重构法、重叠网格法、域动分层法三种工程易行的动网格方法的仿真结果,并得到如下结论:三种方法在整流罩关闭状态下的定常流场结果一致,均能捕捉到非定常开罩过程的典型特征,得到正确的起动结果;在非定常过程中光顺重构法的分离区吞入速度慢于重叠网格法和域动分层法;重叠网格法的计算通用性最好,域动分层法的计算速度最快,光顺重构法的理论精度最高;由于光顺重构法的网格更新对于复杂模型容易失败,域动分层法只能处理运动轨迹已知的问题,三维动力学耦合计算建议采用重叠网格法;在进行整流罩的三维设计时,应考虑溢流效应以缩小整流罩前方的大分离区,降低飞行器的控制及热防护上的困难。     

临近空间飞行器的滑模变结构解耦控制

建立了临近空间滑翔飞行器六自由度运动模型,针对模型具有的快时变、强耦合、强非线性和不确定性特点,应用动态逆方法和滑模变结构控制方法分别设计了内环解耦控制器和外环鲁棒控制器,实现了解耦性与鲁棒性的有机结合,显著提高了控制系统性能.内环采用反馈线性化方法实现了姿态运动模型的伪线性化;外环滑模变结构控制器采用等速趋近律,采用饱和函数法抑制抖振现象,有效抑制外界干扰和参数偏差.仿真结果表明:基于动态逆的滑模变结构控制系统可以准确跟踪攻角、侧滑角和倾侧角指令,对外界干扰和参数偏差具有较强的鲁棒性.     

基于故障观测器的无人机直接自修复控制

提出一种基于故障观测器的无人机直接自修复控制。首先,根据系统本身存在的故障,设计了一个非线性故障观测器对其进行观测。其次,设计了一个快速终端滑模面和直接自修复控制器,将指数函数和符号函数引入到新型滑模面里。同时引入了自适应技术,对不确定的故障估计其上界。最后,通过对无人机进行了相应的仿真数值验证得出所提方法的有效性。