电机智能制造信息化平台

通过对电机制造工艺的分析,以及实地调研电机生产企业运行现状的基础上,针对电机制造工艺复杂、人工依赖大等特点提出了一种电机智能制造信息化平台建设方案。就整体信息系统提出了基于电机行业的工厂模型建立以及系统集成的建议,为电机行业建设智能制造工厂、优化生产管理提供参考。     

Deterministic pion and muon transport in Earth’s atmosphere

An accurate understanding of the physical interactions and transport of space radiation is important for safe and efficient space operations. Secondary particles produced by primary particle interactions with intervening materials are an important contribution to radiation risk. Pions are copiously produced in the nuclear interactions typical of space radiations and can therefore be an important contribution to radiation exposure. Charged pions decay almost exclusively to muons. As a consequence, muons must also be considered in space radiation exposure studies. In this work, the NASA space radiation transport code HZETRN has been extended to include the transport of charged pions and muons. The relevant transport equation, solution method, and implemented cross sections are reviewed. Muon production in the Earth’s upper atmosphere is then investigated, and comparisons with recent balloon flight measurements of differential muon flux are presented. Muon production from the updated version of HZETRN is found to match the experimental data well.     

空间细胞机器人面向桁架在轨攀爬步态分析

面向空间在轨装配维修过程中的攀爬移动问题,基于空间细胞机器人(CSR)理念,提出连接细胞、转动细胞、末端执行细胞三种基本细胞单元。利用图论和拓扑学原理,在关联矩阵的基础上进行改进得到一种细胞迁移矩阵,直观准确地表达细胞机器人任意构型,以及不同节点之间的组织迁移过程。考虑桁架应用环境和细胞机器人自身的特点,划分出三种广义双杆攀爬工况,能够覆盖所有桁架攀爬任务需求。利用基于旋量理论的指数积公式进行不失一般性运动学分析。基于一致性、重复性以及无干涉原则,针对每种攀爬工况提出相应的攀爬步态,进行数值仿真分析,对比不同步态细胞机器人的关节力矩、能耗以及末端轨迹所占据工作空间等参数。仿真结果对空间机器人在轨攀爬路径规划以及控制方式的研究具有重要理论意义和工程价值。     

飞机装配型架接头定位器的自动设计

接头定位器是现代飞机装配型架上最为常用的定位元件。为了简化接头定位器的设计过程,提高设计质量和效率,在FixCAD系统研制的基础上提出并开展了接头定位器自动设计技术的研究和开发。内容包括:(1)在分析接头定位器结构及其设计特点的基础上,提出并建立接头定位器的结构模型和设计模型;(2)研究接头定位器设计的知识和经验细节,建立可计算的推理原则和参数关系式;(3)基于接头定位器的结构模型、设计模型和设计知识,构建接头定位器的自动设计算法,以及应用该算法开发"典型接头定位器自动设计"模块。     

翼面结构/颤振主动控制律一体化设计

在气动弹性领域内对结构 /控制一体化设计作了初步的探索与研究。针对采用加速度传感器的气动伺服弹性模型 ,建立了在拉普拉斯域中颤振速度对结构设计变量及控制设计变量的解析导数表达式。同时也建立了奇异值对结构设计变量的解析导数表达式。对一矩形机翼以输出反馈的形式进行了结构 /控制一体化设计。目标函数为结构重量最轻 ,满足闭环系统颤振速度和以奇异值为基础的鲁棒稳定性指标约束 ,取得了较好的计算结果     

Who is who in Algol-land ? - Part II -

In part I (De Greve and Packet) we have investigated the occurrence of reversed phases of mass-transfer during Case A evolution in close binaries. If the initial period of a system is shorter than 1–2 days (Early Case A) the reversed phase starts before core hydrogen exhaustion of the gainer (part I). This type of evolution is characterized by at least two phases of slow mass-transfer. We have computed the evolution of four Early Case A systems with initial masses of the loser equal to 3 Mo and 5 Mo. These four systems start mass-exchange when Xc of the primary has decreased to 0.525 (75% of its initial value). They all experience two phases of slow mass-transfer. We find that both phases have about the same duration for all systems. The mass ratios are clearly distinct, being closer to unity during the first phase. In the Hertzsprung-Russell, mass-radius and mass-luminosity diagrams both components remain close to the main-sequence band during slow mass-transfer. Evolution as an Algol is ended when both components overflow their outer critical surface after a second reversal of the mass-transfer. Observed Algol systems evolving in Early Case A are scarce. A search thruogh the catalogue by Giuricin et al. gives us the following candidates: X Tri, SX Aur and V Pup. Based on their mass ratios, SX Aur can tentatively be assigned to the first phase of slow mass transfer and X Tri to the second phase. For V Pup (which is more massive) this choice can not be made with certainty.     

气动弹性研究的新进展

 本文概述近年来国内气动弹性研究的若干新进展。主要包括,跨音速非定常空气动力计算,航空结构动力分析系统H AJIF-Ⅱ及其应用,飞机结构多约束优化设计系统YIDOYU-Ⅰ,外挂物颤振的试验研究,以及颤振主动抑制。     

Solar flares as sources of energetic particles

In this paper a review is presented of the present status of our knowledge of solar flare phenomena with special emphasis on the production of suprathermal particles and their solar effects. Of these energetic particles electrons play an important role since they produce the X-ray and radiobursts observed during many flares. Also, during their slowing down to thermal energies they contribute to the heating of localized regions in the solar atmosphere, through energy exchange with the ambient electrons. Observable radiations of energetic protons, and other nuclei, are produced through nuclear interactions leading to the emissions of gamma-ray lines. Detectable fluxes of these gamma-ray lines are produced only in the most powerful flares. Also the nuclei that enter into deeper layers of the solar atmosphere transfer most of their kinetic energy to the ambient plasma.     

Intelligent UUVs: Some issues on ROV dynamic positioning

Intelligent unmanned underwater vehicles (UUVs) fall under two main group categories: the remotely operated vehicles (ROVs), which are characterized by remote operation and presence of a tether cable; and the autonomous underwater vehicles (AUVs), which are characterized by their autonomous behavior and absence of a tether cable. One fundamental issue of the UUV design is the dynamic position control system. This system plays a crucial role together with the sensor architecture in the degree of system autonomy that can be achieved. This paper is concerned with a few issues when dynamically positioning remotely operated underwater vehicles (ROVs). By restricting the operating regime of ROVs to slow velocity requirements the paper investigates the implementation of a few decentralized control strategies and compare their performance measures, which are assessed by simulating a nonlinear ROV system model for each control strategy. Issues concerning input tracking, disturbance rejection, and plant variations are discussed. The evaluations consider the use of linear PID feedback and feedforward variants, and a robust nonlinear control strategies applied to a full order, fully coupled, and nonlinear vehicle model. These evaluations consider a vehicle undertaking standard mission activities where the tether cable dynamics, with load estimates obtained from a lumped mass cable model, and the vehicle actuator system are present. The paper shows that much of the performance deterioration may be attributed mainly due to cable inertia. The authors also verify that the nonlinear robust control strategy does not necessarily allow for better performance over the linear feedback control strategies implemented when vehicle motions are confined to slow velocity profiles. These and other partial results will aid the design of the control system for an underwater vehicle currently under construction     

基于非线性试验气动力的飞机静气动弹性响应分析

分别使用线性和非线性静气动弹性分析方法,对某飞机纵向静气动弹性响应特性随飞行动压、攻角、平尾偏度和纵向过载变化的趋势进行了分析,并将分析结果和飞行试验进行了比较。线性方法的气动力计算使用亚音速偶极子格网法。非线性方法由风洞试验提供刚体气动力,并使用线性气动力影响系数矩阵对其进行弹性化处理。通过对两种方法的计算结果进行对比分析可以看出:①使用刚体试验气动力的非线性分析方法能够获得和飞行试验比较一致的结果;②在线性方法所提供的结果中,翼面的弯曲变形及剪力、弯矩和扭矩等部分参数能为初步设计提供大致参考,但气动力系数的弹性增量、翼面的扭转变形、翼面的剪力、弯矩和扭矩的弹性部分可能不能为型号设计提供正确的指导;③不论刚体气动力为线性还是非线性,气动力系数随动压变化的趋势均呈线性。