航材保障者与保障对象的辩证关系分析

本文深入分析了航材保障工作中保障者与保障对象的辨证关系,为科学的航材保障工作的顺利开展扫除障碍,促进装备全寿命周期效能费用比的全面提升。     

核心机技术在发动机研制中的作用和地位

在核心机及基本发动机基础上进行不同推力或功率和用途的系列发动机发展,在国外已经得到了普遍推广,在发动机全寿命期内其发展的技术途径具有巨大的优越性.因此,进行核心机及其发动机派生发展的方法研究是十分必要的     

四季沐歌，太阳能的大光热时代

自上世纪701年代末，我国引进全玻璃真空集热管的样管，并诞生了第一台太阳能热水器，到1987年制造出第一支全玻璃真空集热管，中国的太阳能热水器行业经过了30多年的发展，迅速崛起。目前，我国是世界上最大的太阳能热水器生产国和使用国。在世界能源危机不断加剧，环保问题日益突出的大背景下，太阳能行业正受到越来越多的关注，发展前景十分广阔。     

单片微机在控制模型姿态角中的应用

用廉价单片微机８０９８装置，控制多台大功率步进电机，实现模型姿态角的控制，并对如何利用软件来提高步进电机的运行频率，模型姿态角β、α和下转盘进行跟踪显示等有关技术进行了探讨。     

来自火星的闹剧

火星是太阳的第四颗行星，它的公转和自转姿态与地球差不多，它的公转轨道周期为687天，1年约合地球上的2年。它在天空中时而顺行，时而逆行。这颗被我们的祖先称为“萤惑”的红色星球确实给我们带来了许多疑惑。     

全空域数字多波束天线技术研究

针对航天领域全空域多目标管理使用需求,设计了一种基于富勒烯结构的赋型数字多波阵列天线,介绍了数字多波束信号收发处理工作原理及赋形阵列结构设计方案,研究了基于赋型阵列天线的波束滑动行走模式、多波束工作模式、波束增强模式,建立了赋形阵列天线数学仿真模型,对阵列天线波束增益一致性、波束宽度一致性、多波束方向图、波束增强性能进...     

超声速飞行器油箱全方程控制模拟气动加热试验研究

超声速飞行器油箱受气动加热影响,其外表面不断与来流进行热交换,油箱内部的燃油也会受到气动加热影响而使燃油温度及供油温度不断升高,应用全方程控制加热试验技术,在地面进行超声速气动加热模拟条件下飞行器油箱传热试验,在试验中经参数测量获得了油箱供油特性,结果表明全方程控制加热试验技术准确模拟真实油箱气动加热状态,为油箱供油系统设计及性能分析提供试验验证方法,测量得到的油箱内燃油温度为277℃,供油温度为126℃,满足冲压发动机不能高于150°C的要求。     

Multi-sensor control for precise assembly of optical components

In order to perform an optical assembly accurately, a multi-sensor control strategy is developed which includes an attitude measurement system, a vision system, a loss measurement system and a force sensor. A 3-DOF attitude measuring method using linear variable differential transformers （LVDT） is designed to adjust the relation of position and attitude between the spher- ical mirror and the resonator. A micro vision feedback system is set up to extract the light beam and the diaphragm, which can achieve the coarse positioning of the spherical mirror in the optical assembly process. A rapid self-correlation method is presented to analyze the spectrum signal for the fine positioning. In order to prevent the damage of the optical components and realize sealing of the resonator, a hybrid force-position control is constructed to control the contact force of the optical components. The experimental results show that the proposed multi-sensor control strategy succeeds in accomplishing the precise assembly of the optical components, which consists of parallel adjustment, macro coarse adjustment, macro approach, micro fine adjustment, micro approach and optical contact. Therefore, the results validate the multi-sensor control strategy.     

Finite-time sliding mode attitude control for a reentry vehicle with blended aerodynamic surfaces and a reaction control system

This paper proposes a finite-time robust flight controller, targeting for a reentry vehicle with blended aerodynamic surfaces and a reaction control system(RCS). Firstly, a novel finite-time attitude controller is pointed out with the introduction of a nonsingular finite-time sliding mode manifold. The attitude tracking errors are mathematically proved to converge to zero within finite time which can be estimated. In order to improve the performance, a second-order finite-time sliding mode controller is further developed to effectively alleviate chattering without any deterioration of robustness and accuracy. Moreover, an optimization control allocation algorithm, using linear programming and a pulse-width pulse-frequency(PWPF) modulator, is designed to allocate torque commands for all the aerodynamic surface deflections and on–off switching-states of RCS thrusters.Simulations are provided for the reentry vehicle considering uncertain parameters and external disturbances for practical purposes, and the results demonstrate the effectiveness and robustness of the attitude control system.