采煤机惯性导航定位动态零速修正技术

基于捷联惯性导航与轴编码器组合的采煤机惯性导航定位是综采工作面可行的采煤机定位技术。惯性导航提供姿态角参数，轴编码器提供速度参数，采煤机惯性导航定位利用航位推算算法解算出东北天坐标系下的位置坐标。为了进一步提高定位精度，在消除确定性偏差的基础上，根据惯性导航姿态误差方程，以东、北、天3个方向的平台失准角为状态量构建状态方程，根据动态零速修正技术的非完整约束条件，以采煤机坐标系横向和垂直方向速度值为观测量构建量测方程，建立卡尔曼滤波模型，并进行移动平台模拟采煤机运行试验验证。在试验条件下，第3刀导航东、北方向最大误差分别由0.639 7，0.856 7 m减小为0.456 4，0.594 2 m。第4刀导航东、北方向最大误差分别由0.644 4，0.910 6 m减小为0.466 5，0.603 0 m。东、北方向定位精度提升了30%。     

带权决策表的属性约简

属性约简是粗糙集理论的重要应用。考虑将决策表中的每行都作为一条决策规则时，若把表中出现相同决策规则的次数作为权，可得到带权决策表。提出了关于带权决策表的正域约简相应的辨识矩阵并给出了证明，从而得到了约简算法。相比于决策表中的正域约简时发现，通过将决策表转化为带权决策表后，再利用算法1进行约简时，其在一定程度上优于前者。提出了近似分类精度约简相应的辨识矩阵并给出了证明。对于2个算法，在选取的UCI数据集上进行了实验验证。通过实验进一步说明了所提出算法的可行性和有效性。     

基于船载卫星通信三轴天线的跟踪搜索技术

针对船载卫星通信三轴天线跟踪系统,介绍了船载三轴天线的系统组成,提出了一种基于捷联惯导的船载三轴天线跟踪搜索技术。天线以目标地理角为中心,通过坐标转换将目标地理角转换为天线的目标甲板角,调整AEC三轴使其及时准确地跟随目标甲板角。目前,该方法已经成功应用于多种船载三轴天线。实践表明,该方法能够快速准确地搜索到目标卫星,并实现对目标卫星的稳定跟踪。     

Meso-structure construction and effective modulus simulation of PBXs

ABSTRACT

The polymer-bonded explosive (PBX) is a kind of multi-phase composite consisting of the polymeric binder and embedded energetic particles, in which the particle volume fraction (PVF) is often higher than 90%. In the present work, by using the Voronoi-polygon generation method along with the concept of gradation to generate Voronoi particles with given gradation, and with further operations including modification, shrinking, smoothing, etc. to the particles, a new meso-structure construction method for PBXs is proposed. The constructed meso-structures possess good gradation relationship and have high PVFs (94.99% in maximum) simultaneously. The strict periodicity on the boundaries of the meso-structure can also be achieved. To verify the constructed PBX meso-structures, the numerical manifold method (NMM) is used to simulate the effective modulus of the constructed meso-structures by considering different influencing factors such as the size of meso-structure, PVF, gradation, and initial defects, etc. The simulation results are analyzed qualitatively, and the causes of differences between the simulation results and available experimental results or other numerical results are discussed. The validity of the proposed method for the construction of PBX meso-structures is verified. This work also provides foundations for the further numerical studies of the mechanical and thermal behaviors of PBXs at the mesoscale.     

深水水下管汇的结构设计概述

以南海某油气田的深水水下管汇为例,结合管汇的功能需求、结构组成、结构计算等,对深水水下管汇的结构设计进行了概述。     

基于流场分析的Y型对接式压裂管汇布局研究

为提高压裂管汇的使用寿命,在传统的直角对接式布局基础上,设计了一种Y型对接式压裂管汇撬。运用Eulerian-Lagrangian方法与流体分析软件,分析获得不同结构参数下Y型对接式压裂管汇的流场压力、流场速度、冲蚀分布规律,并对Y型对接式布局进行优化。研究表明,随着对接角的增大,Y型对接式压裂管汇的流场压力、速度分布越不稳定,最大冲蚀速率随之减少,平均冲蚀速率随之增大; 在对接四通拐角处设置过渡倒圆后,随着倒圆半径的增大,最大冲蚀速率及平均冲蚀速率随之减小; 在对接角45°、倒圆半径20 mm时,最大冲蚀速率减小37.6%,平均冲蚀速率减少49.7%; Y型对接式压裂管汇的冲蚀速率比直角对接式结构有显著减小,提高管汇使用寿命。     

A novel minimum weight formulation of topology optimization implemented with reanalysis approach

In this paper, we develop an efficient diagonal quadratic optimization formulation for minimum weight design problem subject to multiple constraints. A high-efficiency computational approach of topology optimization is implemented within the framework of approximate reanalysis. The key point of the formulation is the introduction of the reciprocal-type variables. The topology optimization seeking for minimum weight can be transformed as a sequence of quadratic program with separable and strictly positive definite Hessian matrix, thus can be solved by a sequential quadratic programming approach. A modified sensitivity filtering scheme is suggested to remove undesirable checkerboard patterns and mesh dependence. Several typical examples are provided to validate the presented approach. It is observed that the optimized structure can achieve lighter weight than those from the established method by the demonstrative numerical test. Considerable computational savings can be achieved without loss of accuracy of the final design for 3D structure. Moreover, the effects of multiple constraints and upper bound of the allowable compliance upon the optimized designs are investigated by numerical examples.     

An engineering method for complex structural optimization involving both size and topology design variables

This work presents an engineering method for optimizing structures made of bars, beams, plates, or a combination of those components. Corresponding problems involve both continuous (size) and discrete (topology) variables. Using a branched multipoint approximate function, which involves such mixed variables, a series of sequential approximate problems are constructed to make the primal problem explicit. To solve the approximate problems, genetic algorithm (GA) is utilized to optimize discrete variables, and when calculating individual fitness values in GA, a second-level approximate problem only involving retained continuous variables is built to optimize continuous variables. The solution to the second-level approximate problem can be easily obtained with dual methods. Structural analyses are only needed before improving the branched approximate functions in the iteration cycles. The method aims at optimal design of discrete structures consisting of bars, beams, plates, or other components. Numerical examples are given to illustrate its effectiveness, including frame topology optimization, layout optimization of stiffeners modeled with beams or shells, concurrent layout optimization of beam and shell components, and an application in a microsatellite structure. Optimization results show that the number of structural analyses is dramatically decreased when compared with pure GA while even comparable to pure sizing optimization.     

球型惯性元件配合间隙差动共焦精密测量方法

配合间隙是决定球型惯性器件精度和可靠性的关键参数之一,针对球型惯性器球面元件表面有缺口且未完全抛光导致曲率半径难以精确测量,进而难以准确控制球碗、球冠配合间隙瓶颈问题,提出了一种球面惯性元件配合间隙激光差动共焦高精度方法。该方法利用抗散射的激光差动共焦曲率半径测量方法分别对球碗、球冠的曲率半径进行测量,然后利用差动共焦曲率半径测量系统测得的球碗和球冠的半径差来控制球型惯性器球面的配合间隙。理论分析与实验验证表明:该方法测量球冠和球碗配合间隙的相对扩展不确定度优于20×10~(-6),其为惯性器件球冠和球碗配合间隙的高精度测量与控制提供了一种全新的技术手段。     

混合式惯导系统自标定技术研究

混合式惯导系统是一种集平台式、捷联式、旋转式惯导系统优点于一体的新型惯导系统。该型惯导可利用自身的旋转机构和高精度、高分辨率角度传感器实现不拆机条件下的误差参数自标定功能,极大简化了标校流程和系统维护工作量,有利于武器平台和作战系统效能的发挥。针对混合式惯导系统的结构特点和典型的旋转方式进行了误差分析,给出了误差参数自标定的设计原则和方法,并用混合式惯导原理样机进行了验证,结果表明,所设计的自标定方案能够在不拆机条件下利用自身旋转机构完成对陀螺漂移、加计零偏、刻度系数误差及安装偏角等参数进行精确估计,因此具有较高的理论意义和工程应用价值。