资源三号卫星控制系统概述及在轨验证

资源三号(ZY-3)卫星是一颗民用高分辨率立体测绘卫星.针对ZY-3卫星特点,对控制系统方案进行概述.通过星敏感器相对基准的标定以及星敏感器和陀螺联合滤波实现高精度姿态确定;通过设计结构滤波器和磁卸载力矩的前馈补偿实现三轴高稳定度控制;通过轨迹规划实现大角度侧摆机动.根据卫星在轨运行数据,给出相应指标实现情况,对姿态控制系统的方案和指标满足情况进行在轨验证.     

An improved procedure for manufacture of 3D tubes with springback concerned in flexible bending process

Three dimensional (3D) tubes, which possess the characteristics of space saving, lightweight and high strength, are widely used in many high-end industries such as aviation, aerospace, automobile and shipbuilding. However, when manufacturing a 3D tube in flexible bending process, springback is a big obstacle for improving the forming quality. In this paper, a new comprehensive strategy for springback control of 3D tubes is proposed. The strategy can be described as follows: (1) define the desired shape and manufacture shape; (2) optimize the manufacture shape using two tooling design methods (e.g. DA (displacement adjustment) method and B&T (bending and twisting) method presented in this paper); (3) make a discretization of the manufacture shape to acquire the optimized forming parameters. Additionally, experiment is implemented to validate the effectiveness of the new strategy. Results show that forming parameters acquired by the new strategy are partially effective. The new strategy also demonstrates that, during 3D tubes forming, the deviation caused by over-bent elements can be counteracted by the deficient-bent elements. This principle is helpful to reduce the difficulty of parameter determination in future.     

Improving seeking precision by utilizing ghost imaging in a semi-active quadrant detection seeker

Conventional semi-active laser guidance takes advantage of the laser designator to illuminate the stable and uniform laser spot on target precisely. The seeker collects the reflected light by a quadrant detector and outputs the relative position information to guide the missile to the illuminating laser spot. However, the designation and guidance accuracy could be jeopardized by the randomly drifting of laser spot caused by the instability of designation platform and air turbulence. In this work, ghost imaging technique is adapted to a quadrant detector semi-active seeker by utilizing structured illumination on the target. With a series of structured illumination masks, the signals from the quadrant detector are multiplexed to perform calculation of the target relative position as well as image reconstruction of the illuminated area simultaneously. Automatic target recognition methods could be further applied to the reconstructed image to calculate the designating error and correct the guidance. The results of simulation and experiment demonstrate that the proposed method could improve the guidance accuracy in many circumstances which would lead to attacking deviation if conventional semi-active laser guidance is used.     

3D multiphysic simulations of energy field and material process in radial ultrasonic rolling electrochemical micromachining

The radial ultrasonic rolling electrochemical micromachining(RUR-EMM) combined rolling electrochemical micromachining(R-EMM) and ultrasonic vibration was studied in this paper. The fundamental understanding of the machining process especially the interaction between multiphysics in the interelectrode gap(IEG) was investigated and discussed by the finite element method. The multiphysics coupling model including flow field model, Joule heating model, material dissolution model and vibration model ...     

近地小行星2016HO3表面温度建模研究

2019年4月18日,中国国家航天局(CNSA)公布了小行星探测计划,将近地小行星2016HO3作为探测任务目标之一。主要梳理了2016HO3热环境分析的要素,通过调研国际上目前观测数据,得到2016HO3的初步环境参数,使用近地小行星热模型(NEATM)与小行星热物理模型(TPM)开展了小行星2016HO3表面温度场建模与分析,综合得出小行星温度上限为412 K;同时结合其可能的自转条件,仿真分析了不同位置的昼夜温差变化特性,发现2016HO3最大温差大约为30 K。由于两个模型均不能直接处理极夜情况,在TPM模型基础上采用对自转周期光照进行平均思路,给出了极夜条件下的温度分析方法,并获得小行星2016HO3的温度下限。     

基于同波束干涉的空间三维相对位置测量研究

针对深空探测器相对位置精确测量需求,建立了空间三维相对位置测量模型,研究了基于单基线同波束干涉测量(Same-beam VLBI,SBI)的空间三维位置最小二乘解算方法。利用"嫦娥3号"着陆器的测控天线与定向天线的SBI实测数据,验证了测量模型与解算方法的有效性。结果显示:SBI干涉时延随机误差约0.225 ps(0.07 mm);测控天线与定向天线之间距离误差约0.216 m,方向误差约30.4°。该研究结果有望应用于后续深空探测任务譬如"嫦娥5号"器间高精度相对测量中。     

微小卫星三轴稳定磁控算法工程应用

为降低微小卫星的成本和提高卫星可靠性,研究采用磁力矩器作为唯一执行机构对卫星进行三轴姿态稳定的问题。利用线性二次型调节器（LinearQuadraticRegulator,LQR）最优控制理论分别设计无限时间状态调节器和定常增益状态调节器,实现纯磁控下的微小卫星对地三轴稳定控制。同时结合卫星实际工程应用,以在轨飞行的“开拓一号”卫星为研究对象,分析卫星惯量积、轨道倾角、剩磁干扰、气动干扰等因素对控制精度的影响。仿真结果表明LQR控制器具有稳定性和实用性,在小干扰情况下,控制精度较高。     

S型管内超临界航空煤油的裂解与结焦研究

再生主动冷却是超燃冲压发动机热防护的关键技术之一。为了探究冷却通道中弯管结构产生的二次流对碳氢燃料裂解与结焦特性的影响,使用S型圆管实验段进行了RP-3航空煤油超临界裂解结焦实验。重点考察了沿程壁温、产气率、气相产物分布以及S型管结焦沿程分布特征。实验结果表明：由于S型管的结构特点,沿程壁温和结焦分布均呈现出与直管相迥异的特征。在两个弯道区域,离心力产生的二次流加剧湍流混合,强化了局部换热,导致壁温下降。结焦率在弯道结构处出现小幅度局部峰值,在出口温度为700℃时,第二个弯道处平均结焦率比中间直管段提高了101%~170%。这可能与弯道处对应的局部高温、输运作用增强和局部摩擦阻力的增大三者综合作用有关。此外,还发现S型管产气率比直管更高,在出口温度为700℃时提高了10.2%~14.9%。可能是弯管处内侧壁面附近的燃料受局部高温影响,裂解反应加剧,产气率增加。而S型管的特殊结构对裂解的反应路径无明显影响,因此气相产物分布与直管并无明显差异。