多臂空间机器人的视觉伺服与协调控制

针对多臂空间机器人自主目标抓捕任务，首先建立多臂空间机器人的运动模型和其与目标的相对运动模型，采用Kane方法建立多臂空间机器人的动力学模型；其次，研究基于视觉伺服的机械臂在线轨迹规划算法，并引入零反作用机动，消除机械臂运动对平台姿态的扰动；再次，在不使用零反作用机动功能时，分别使用基于角动量前馈补偿的协调控制算法和逆动力学方法设计了协调控制器，在机械臂运动时保持平台姿态和相对目标的位置。最后，开发了基于Matlab的仿真软件MASS（多臂空间机器人仿真），仿真结果校验了上述方法的有效性。     

Multi-mode optimal fuzzy active vibration control of composite beams laminated with photostrictive actuators

Firstly, a multi-field coupling finite element formulation of composited beam laminated with the photostrictive actuators is developed in this paper. Moreover, an optimal fuzzy active control algorithm is also proposed on the basis of the combination of optimal control and fuzzy one.This method opens a new avenue to resolve the contradiction between the linear system control method and nonlinear actuating characteristics of photostrictive actuators. The desired control for suppressing multi-modal vibration of photoelectric laminated beam is firstly obtained through optimal control and then the fuzzy control is used to approach the desired mechanical strain induced by photostrictive actuators. Thus, the multi-mode vibration control of beam is realized.In the design process of optimal fuzzy controller, the design of fuzzy control is independent of optimal control. The simulation results demonstrate that the proposed control method can effectively realize multi-modal vibration control of photoelectric laminated beams, and the control effect of optimal fuzzy control is better than that of optimal state feedback control.     

A concept mission for the Stellar Population and Evolution with Cubesats (SPEC)

Binary or multiple stellar systems, constituting almost a third of the content of the Milky Way, represent a high priority astronomical target due to their repercussions on the stellar dynamical and evolutionary parameters. Moreover the spectral study of such class of stars allows to better constrain the evolutionary theories of the Galactic stellar populations. By resolving the members of stellar systems through photometric observations we are able to perform more detailed measurements to infer their mass. In this paper we investigate the feasibility of a cubesat based mission including an optical payload to directly optically discriminate the members of a selected sample of binary systems. The scientific targets, consisting 11?M class dwarf stars binary systems, have been extracted from the already studied Riaz catalogue. These subset has been selected considering the star distance, the members angular separation, and the distance from the Galactic plane (due to limit the background and foreground contamination). The satellite concept is based on a 6 unit Cubesat embedding some commercial off the shelf components and an ad hoc designed optical payload occupying almost 4 units. The optical configuration has been chosen in order to fit the angular resolution requirements, as derived from the target characteristics. Moreover, according to the optical analysis and the computed field of view some requirements on the attitude control system have been inferred and fulfilled by the component selection. The paper is organized as in the following: a brief scientific introduction is made; consequently the project is described with particular attention to the optical design and the standard sub-systems; finally the conclusions are drawn and the future perspectives are investigated.     

基于位移和力值组合的静重式力标准机砝码加卸载控制方法研究

介绍了一种基于位移和力值组合的静重式力标准机砝码加卸载的控制方法，通过监测砝码的移动量和参考力传感器叠加系统的力值量，实时调整加卸载机构的加卸载速度，以实现对被检力传感器的平滑加卸载的目的。该方法有效解决了吊挂在加载过程中产生较大摆动，影响力标准机复现力值准确度的问题，同时也消除了力值过冲现象，避免了因逆程效应而导致的力传感器输出偏差。     

高温铝合金电磁超声检测回波特性及因素分析

针对高温铝合金在线检测条件下，温度对铝合金电磁超声检测回波特性的影响规律尚不明确、高温检测时缺陷定量/定位补偿困难这一难题，以螺旋线圈电磁超声换能器（EMAT）为例，建立了高温铝合金EMAT检测过程的场路耦合有限元模型；研究了温度对EMAT激励/接收换能效率、EMAT激励/接收电路的功率分配特性、超声传播过程中的扩散/介质衰减特性、回波幅值和超声声速等因素的影响规律；研制了耐高温EMAT探头，对20~500℃高温铝合金试样进行了检测实验，并测定了高温铝合金的超声介质衰减系数和超声声速。在仿真和实验相结合的基础上，分析了高温检测时超声回波幅值变化特性及其影响因素。结果表明：对于铝合金这类非铁磁性金属材料，导致高温时超声回波幅值下降的主要原因是超声介质衰减系数随着温度的升高而增大，其次为高温时EMAT激励/接收电路的功率分配特性的改变。在激励EMAT在试样表面形成的洛伦兹力不变的条件下，其所激励的超声波回波幅值具有随着温度的增加而增加的特点，可以有效减缓超声回波幅值下降的趋势。     

基于有限Fourier级数的航天器转移轨迹设计

针对航天器小推力转移轨迹的初始设计问题，利用基于三阶Fourier级数的设计方法实现了航天器小推力的多圈转移。同时，基于有限Fourier级数的形状法，对具有多个约束条件的小推力多圈转移轨迹进行了优化设计。选取了共面同轴同偏心率的初始和末端轨道位置，对所提出的方法进行了仿真验证。结果表明：与改进逆五阶多项式形状法相比，所提出的方法虽然增加了转移时间，但当转移圈数为5圈、有限Fourier级数的项数为10时，可减少将近75%的转移速度增量，同时大大减小了所需的最大推力加速度的值。     

直线模拟加载系统的研究进展与发展趋势

直线模拟加载系统是一种用于在实验室条件下模拟承载对象工作时所受直线负载力的半实物仿真系统，可用于模拟各类飞行器关键部件在工作过程中所受的气体阻力载荷。针对目前常用的机械式、电液式和电动式直线模拟加载系统，分析其基本加载原理和研究进展，结合自行研制的电动式直线模拟加载系统进行了深入探讨。针对多余力抑制方法的关键问题，详细论述了直线负载模拟器的结构补偿方法和控制策略。最后，展望了直线模拟加载系统的发展趋势，归纳了电动式直线模拟加载系统的高精度、大载荷发展方向。     

基于梯度提升决策树的量子科学实验卫星光学实验预测

量子科学实验卫星在轨运行期间完成4种光学实验，地面监测人员通过遥测参数阈值判断卫星是否进行光学实验、实验类型及实验结果.这种方法需要预先设定大量阈值，并且这些阈值需要根据在轨卫星重新设定，可扩展性较差.针对以上问题，提出一种基于机器学习的光学实验判别方法，将量子科学实验卫星的光学实验监测任务抽象为机器学习中的多元分类问题，构建分类模型，利用量子科学实验卫星的真实历史遥测数据对模型进行训练，并通过真实实验计划对训练得到的模型进行验证.实验结果表明，本文提出的方法在没有专家先验知识的前提下，判别准确率达到99%，可用于量子科学实验卫星光学实验的实时监测任务.提出的基于机器学习的判别方法具有较强的可扩展性，可应用于卫星在轨运行的其他监测任务.      

基于变马赫数的五孔探针三维插值方法

探讨了五孔探针气动数据的插值方法,为提高插值精度,开发了基于传统线性插值法的三维线性插值法。该方法把同一探针在不同马赫数下的校准图形成三维数据库,将实验数据通过三维图进行插值。并使用改进前后的两种插值方法分别对校准风洞测得的数据进行整理,对比结果证明:在实验工况连续变化的情况下,三维线性插值法在插值精度上要优于传统线性插值法。特别是在来流马赫数变化较大时,该方法可以改善单一校准文件处理造成的数据精度问题,可用于自动化流场采集系统,为流场高速高精度采集奠定基础。     

A progressive approach to predict shot peening process parameters for forming integral panel of Al7050-T7451

In this paper, a progressive approach to predict the multiple shot peening process parameters for complex integral panel is proposed. Firstly, the invariable parameters in the forming process including shot size, mass flow, peening distance and peening angle are determined according to the empirical and machine type. Then, the optimal value of air pressure for the whole shot peening is selected by the experimental data. Finally, the feeding speed for every shot peening path is predicted by regression equation. The integral panel part with thickness from 2 mm to 5 mm and curvature radius from 3200 mm to 16000 mm is taken as a research object, and four experiments are conducted. In order to design specimens for acquiring the forming data, one experiment is conducted to compare the curvature radius of the plate and stringer-structural specimens, which were peened along the middle of the two stringers. The most striking finding of this experiment is that the outer shape error range is below 3.9%, so the plate specimens can be used in predicting feeding speed of the integral panel. The second experiment is performed and results show that when the coverage reaches the limit of 80%, the minimum feeding speed is 50 mm/s. By this feeding speed, the forming curvature radius of the specimens with different thickness from the third experiment is measured and compared with the research object, and the optimal air pressure is 0.15 MPa. Then, the plate specimens with thickness from 2 mm to 5 mm are peened in the fourth experiment, and the measured curvature radius data are used to calculate the feeding speed of different shot peening path by regressive analysis method. The algorithm is validated by forming a test part and the average deviation is 0.496 mm. It is shown that the approach can realize the forming of the integral panel precisely.