Prototype Engineering Test Platform of ITER Magnet Gravity Support

ITER magnet gravity support （GS） has been redesigned as a structure of pre- assembled nmlti-flexible plates instead of the original welded structure. In the past several years, engineering tests of the new structure have been proposed. A prototype engineering test plat- form is being developed. In order to apply the loads/load combinations onto the test mock-up, seven hydraulic bolt tensioners in three directions have been applied to simulate various loads （forces and moments）, through which the deformation of bolts, flexible plates and clamp blocks, the stress distribution in the flexible plates, the friction between the contact surface, etc. can be monitored/tested. The measurement and control system includes seven sets of synchronization controller, a 16-channel strain gauge, 25 sets of displacement sensors, etc. Principles of EDC220 digital controller and development of multi-channel control software are also demonstrated.

蓟县地震台gPhone、DZW和GS-15重力仪重力噪声水平对比

选取蓟县地震台同址观测的3台不同型号重力仪(gPhone、DZW和GS-15)2022年全年的连续观测数据,研究不同类型仪器对环境噪声的响应,计算3种重力仪的重力噪声水平,同时计算地震频段(200~600 s)的地震噪声等级,并与全国gPhone重力仪的地震噪声等级进行对比。结果表明:1)在频率低于10-3 Hz时,扣除固体潮和气压改正可以明显改进重力噪声水平;2)相同台站不同仪器重力噪声水平不同,gPhone型重力仪的背景噪声水平低于DZW型重力仪和GS-15型重力仪,其SNM值为3.355;3)2022年全国gPhone重力仪的地震频段噪声水平均值为5.418,蓟县台的噪声水平平均值为3.465,低于全国的噪声水平。研究结果可为3类重力仪观测数据的研究应用提供参考。

入侵检测中基于IBQGSA的特征选择及SVM参数优化

针对支持向量机(SVM)应用于网络入侵检测时特征选择及分类器参数优化问题,利用改进的二进制量子引力搜索算法(IBQGSA)对入侵特征集及SVM参数进行组合寻优。将入侵特征集及SVM参数看作是二进制量子引力搜索算法中的量子个体并进行组合编码,在使用量子旋转门更新个体位移时,引入动态的位移更新策略,确保算法收敛到全局极值,设计与进化程度及个体适应度值相关的自适应变异概率,提升量子非门变异操作时算法的自适应变异能力。利用KDD CUP 99数据集进行仿真实验,实验结果表明,所提算法能有效地获取最佳特征子集及分类器参数组合,检测效果更好。

基于核主成分分析的GSA-SVM木材单板缺陷识别研究

为支持向量机能够准确识别木材单板表面缺陷,以提高木材单板质量,提出高效准确的单板缺陷核主成分分析(KPCA)的引力搜索算法(GSA)-支持向量机(SVM)识别模型。考虑到图像特征数据间的冗余影响,采用KPCA方法对原始特征数据降维,并通过GSA优化SVM的惩罚因子C和核参数g,建立KPCA-GSA-SVM木材单板缺陷识别模型。基于颜色、纹理、形状3方面的特征以活节、死节、裂纹为研究对象的样本原始数据集,选取8个主要特征(1个颜色特征、1个纹理特征和6个形状特征)作为木材单板识别依据,对木材单板识别模型进行学习训练及预测分析,并与传统粒子群参数优化算法(PSO)构成的KPCA-PSO-SVM识别模型进行识别效果对比。结果表明,基于KPCA-GSA-SVM木材单板识别模型对于活节、死节、裂纹的识别率达到100%、96.78%、100%,较KPCA-PSO-SVM识别模型分别高出21.62%、0.63%、7.41%,且整体耗费时间缩短7.26 s,由此看出预测识别率、识别速度、稳定性高于前者。研究结论从新的角度对单板缺陷进行识别,有助于木材单板缺陷的识别发展。

煤层底板突水危险性GSPCA-LSSVM评价模型

为快速、准确地评价煤层底板突水危险性,选取水压等作为影响因素,以其灰色关联度作为灰色主成分分析（GSPCA）的协方差矩阵,提取信息不重叠的灰色主成分,并将该成分作为最小二乘支持向量机（LSSVM）的输入向量,底板突水危险性作为LSSVM输出向量,建立煤层底板突水危险性GSPCA-LSSVM评价模型;将20组实测数据作为训练样本训练模型,采用回代估计法进行回检;利用训练好的模型对5组检验样本进行评价。结果表明：利用GSPCA提取的主成分考虑原影响因素不完备性,包含其超过91.97%的信息,减少信息冗余;经GSPCA处理后LSSVM计算复杂度降低;用GSPCA-LSSVM模型评价煤层底板突水危险性,结果与实际情况基本吻合。

Measurement of lumber moisture content based on PCA and GSSVM

Lumber moisture content(LMC) is the important parameter to judge the dryness of lumber and the quality of wooden products.Nevertheless the data acquired are mostly redundant and incomplete because of the complexity of the course of drying,by interference factors that exist in the dryness environment and by the physical characteristics of the lumber itself.To improve the measuring accuracy and reliability of LMC,the optimal support vector machine(SVM) algorithm was put forward for regression analysis LMC.Environmental factors such as air temperature and relative humidity were considered,the data of which were extracted with the principle component analysis method.The regression and prediction of SVM was optimized based on the grid search(GS) technique.Groups of data were sampled and analyzed,and simulation comparison of forecasting performance shows that the main component data were extracted to speed up the convergence rate of the optimum algorithm.The GS-SVM shows a better performance in solving the LMC measuring and forecasting problem.

Detection of a half-microgal coseismic gravity change after the Ms7. 0 Lushan earthquake

Because only a small near-field coseismie gravity change signal remains after removal of noise from the accuracy of observations and the time and spatial resolution of the earth＇s surface gravity observation system, it is difficult to verify simulations of dislocation theory. In this study, it is shown that the GS15 gravimeter, located 99.5 km from the epicenter of the Ms7.0 Lushan earthquake on April 20, 2013 at 08 ： 04 UTC ＋ 8, showed the influence of the earthquake from 2013-04-16 to 2013-04-26 after a time calibration, tide correc- tions, drift correction, period correction and relaxation correction were applied to its data. The post-seismic relaxation process of the spring in the gravimeter took approximately 430 minutes and showed a 2. 5 ×10^-8 ms^-2 gravity change. After correcting for the relaxation process, it is shown that a coseismic gravity change of approximately ＋0.59 ＋-0. 4 ~ 10-Sms-2 was observed by the GS15 gravimeter; this agrees with the simulated gravity change of approximately 0.31 ~ 10 -8 ms-2. The rate of the coseismie gravity change and the coseismic vertical displacement, as measured by one-second and one-day sampling interval GPS units, is also consistent with the theoretical rate of change. Therefore, the GS15 gravimeter at the Pixian Station observed a coseismic gravity change after the Ms7.0 Lushan earthquake. This and similar measurements could be applied to test and confirm the theory used for these simulations.

Coordinated control strategy for robotic-assisted gait training with partial body weight support

Walking is the most basic and essential part of the activities of daily living. To enable the elderly and non-ambulatory gait-impaired patients, the repetitive practice of this task, a novel gait training robot(GTR) was designed followed the end-effector principle, and an active partial body weight support(PBWS) system was introduced to facilitate successful gait training. For successful establishment of a walking gait on the GTR with PBWS, the motion laws of the GTR were planned to enable the phase distribution relationships of the cycle step, and the center of gravity(COG) trajectory of the human body during gait training on the GTR was measured. A coordinated control strategy was proposed based on the impedance control principle. A robotic prototype was developed as a platform for evaluating the design concepts and control strategies. Preliminary gait training with a healthy subject was implemented by the robotic-assisted gait training system and the experimental results are encouraging.

Novel Design Method of COG Measurement System Via Supporting Reaction Method

Center of gravity(COG)is an important parameter of projectiles and rockets,for which supporting reaction method(or support reaction method)is an important COG measurement method.Based on this supporting reaction method a novel design method is proposed to determine the key design parameters of the COG measurement system.The method can quantitatively analyze the influence of the design parameters on the COG accuracy,in the measurement system designed with supporting reaction method.Using the principle of static balance,the error propagation theory,and the system accuracy analysis method,the equal-range required sensor precision(RSP)surface and non-equal-range required sensor pair precision(RSPP)adapted surface are adopted.The influence of random errors(like sensor accuracy and distance calibration accuracy)is analyzed.The selection strategy of equal-range and non-equal-range sensors is chosen,and then the recommended calibration accuracy values are obtained.For the quality detection accuracy of±0.6 kg and the axial COG detection accuracy of±1.5 mm,the RSP surface is drawn by the proposed method,and the force sensor with±0.23 kg detection accuracy is selected.The experimental verification meets the accuracy requirements and verifies the effectiveness of the proposed design method for the system parameters of the COG measurement equipment.

Design and Research of Active Gravity Unloading Device for Large Aperture Optical Mirror

The large aperture optical mirror for space is processed and tested in the gravity environment on the ground. After entering space, gravity disappears due to the change of environment, and the mirror surface that has met the engineering requirements on the ground will change, seriously affecting the imaging quality. In order to eliminate the influence of gravity and to ensure the consistency of space and ground, gravity unloading must be performed. In order to meet the requirements of processing and testing for the large aperture space mirror in the state of vertical optical axis, a universal gravity unloading device was proposed. It was an active support and used air cylinders to provide accurate unloading force. First, the design flow of gravity unloading was introduced;then the detailed design of the mechanical structure and control system was given;then the performance parameters of the two types of cylinders were tested and compared, including the force-pressure relationship curve and the force-position relationship curve;finally, the experimental verification of the gravity unloading device was carried out;for a mirror with an aperture of ?2100 mm, the gravity unloading device was designed and a vertical detection optical path was built. The test results showed that by using this gravity unloading device, the actual processing surface accuracy of the mirror was better than 1/50λ-RMS, which met the application requirement of the optical system. Thus, it can be seen that using this gravity unloading device can effectively unload the gravity of the mirror and realize the accurate processing and measurement of the mirror surface. .

大口径激光发射窗口镜多点支撑下结构研究

大口径激光发射窗口窗口镜由于径厚比高,刚度低,在自身重力下会发生变形,即镜面峰谷值(PV值)与均方根值(RMS)值过大,窗口镜会形成透镜,改变了激光发射输出端的发散角,不能满足激光发射系统的精准命中和能量集中的需求。建立了硒化锌材料的光学窗口的有限元仿真模型,计算分析在窗口镜径向支撑与底部安装支撑点结合轴向支撑作用时窗口镜的变形情况,并优化支撑体的材料、数量、位置分布。进行有限元仿真分析后,窗口镜面形精度满足PV值λ≤632.8nm与RMS低于λ/5≤126.56nm,支撑结构设计满足激光发射窗口需求。

适应人体重心起伏的悬吊减重康复系统设计

减重系统对下肢疾病患者的行走康复训练有重要影响。现有的下肢康复外骨骼减重装置大多只考虑如何减去患者体重的百分比,而忽略了患者身体重心的起伏。由于外骨骼的骨盆支架在竖直方向运动轨迹固定,患者步态的微小变化就会导致重心高度与骨盆支架运动轨迹不符,这一差异会作用到患者的骨盆位置,影响下肢关节的活动,并产生额外的风险。针对这一问题,提出通过采集足底压力来预测重心位置变化,并利用获得的重心轨迹解算出应施加的减重力方法,为患者训练提供安全有效的减重系统。所提方法的可行性已获仿真证实,并在研发的外骨骼减重系统上获得实际验证,模糊控制器跟踪重心轨迹的误差相比PID控制减少了21.2%,稳态误差维持在±1 mm范围内,髋膝关节的活动范围相比常规减重分别增加了14.36%和13.77%。

基于结合先验信息的最小支撑稳定器的三维重力正则化反演

如何将先验信息融入地球物理反演,进而改善反演的不适定性,一直是地球物理反演领域的研究热点。将先验信息直接融入目标函数的方法通常会增加目标函数的复杂性。为了不在目标函数上增加约束项,更加简单、方便地实现先验信息的融入,本文以三维重力正则化反演为例,将先验信息融入最小支撑稳定器,实现了对最小支撑稳定器的重构,并设计了单块体和双块体模型,进行对比试验。试验结果表明:相较于基于最小支撑稳定器的三维重力反演结果,基于结合先验信息的最小支撑稳定器的三维重力正则化反演更好地还原了异常体的几何形态和物性分布;此外,基于新方法反演的误差迭代曲线收敛更快,拟合精度更高。故此,通过最小支撑稳定器的重构实现先验信息的融入是可行的,该方法适用于三维重力反演,具有实现方便且不额外增加约束项的优点。

复杂环境下“城中村”改造项目基坑工程实践

随着新型城镇化建设的发展,国家积极推进城市中心城区城市更新。作为城市更新进程中重要的一环,“城中村”改造项目越来越多,基坑工程的环境条件也变得越来越复杂。为了更好地探究改造项目中周边环境的变化对基坑的影响,以上海某“城中村”改造项目为例,研究了复杂环境下“城中村”改造项目基坑工程实践。结果表明,在考虑基坑周边大超载条件下,结合工期及造价要求,选用重力坝的围护形式,并在局部靠边深坑区域采取加角撑或双排桩围护形式进行围护加强,同时采取基坑分区开挖方法,取得了良好的工程效果,可为今后类似工程提供借鉴。

重力式挡土墙在大学城南停车场边坡支护工程中的应用

围绕重力式挡土墙施工技术进行研究,首先阐述了其概念,然后以大学城南停车场边坡支护工程为例,探讨了重力式挡土墙的稳定性及相关施工技术要点,并进行位移监测,经分析监测结果发现工程边坡整体保持在稳定状态,重力式挡土墙施工效果良好,工程采用的施工技术具有可行性。

基于ProCAST铝合金压板铸造工艺优化设计

利用铸造模拟软件ProCAST对承力索座压板凝固过程进行模拟,通过对铸件成形过程当中的速度场与温度场的变化规律进行分析,得出铸件内部缺陷所在位置及产生的原因,对铸造工艺进行优化设计。通过公式计算,将内浇口的横截面积增大到135 mm^(2),直浇道的高度增加到120 mm。对优化后的方案进行模拟验证,结果表明:优化浇注系统的结构和横截面积,确保了铝液在充型凝固时,有良好的补缩通道使高温铝液对缺陷部位能够及时进行补缩,从而消除铸件内部缺陷,使产品合格率得到大幅提高;通过使用ProCAST软件,不仅大大缩短了试验周期,降低了生产成本,也为产品后续的改进提供了理论依据,实现了良好的经济效益。

地铁车辆段上盖的全框支剪力墙结构设计探讨

根据地铁车辆段上盖全框支剪力墙结构设计实践,提出该结构按现行规范设计存在的问题,包括重力二阶效应验算,周期折减系数影响,框支柱剪力调整和厚板设计验算等问题。针对上述问题,建议重力二阶效应验算采用屈曲因子不小于20作为不考虑条件;少砌体墙的(框支)框架层考虑周期折减系数的影响,对(框支)框架层楼层剪力作折减;对于特一级或一级的框支柱的弯矩或剪力调整系数下调,避免调整后剪力远大于中震剪力的不合理情况;盖上剪力墙对厚板的冲切验算用作图法验算。

基于网格搜索的PCA-SVM道路交通标志识别

针对现有识别方法对交通标志的识别精度和算法效率不高的问题,提出了一种基于网格搜索的主成分分析-支持向量机(PCA-SVM)道路交通标志识别方法。该方法首先采用主成分分析(PCA)法对交通标志进行降维处理,提取出交通标志的主元特征,然后利用网格搜索法(GS)对支持向量机(SVM)进行参数优化,最后利用参数优化好的支持向量机分类器实现对交通标志的识别。通过实验仿真,并与现有的其他交通标志识别算法进行分析对比,实验结果表明,本文方法在保证较高识别精度的同时,算法效率得到显著提高。

静载荷与地震载荷作用下ITER重力支撑系统有限元静力分析

针对ITER重力支撑系统的特点,提出了ITER重力支撑系统的有限元静力分析方法。应用AN-SYS软件,建立了ITER重力支撑系统三维实体模型。采用精度比较高,且计算规模又可以接受的单元网格划分方法,进行网格划分。在Volume之间的界面上定义接触单元。得到了支撑系统有限元模型。对同时受静载荷与地震载荷作用的ITER重力支撑系统进行了有限元静力分析。获得了支撑系统各零件的应力分布及最大应力,分析了这些零件的强度。结果表明:TF腿、韧性板、环形支撑和支撑圆柱的最大应力分别出现在TF腿与等效环向壳连接处、韧性板与其下法兰焊接的拐角处、环形支撑上端面与其内部加强筋的交接处、支撑圆柱的上端面,这些最大应力都小于其相应的许用应力,按照ASME压力容器评定标准,支撑系统各零件均满足强度要求。静力分析的结果为ITER重力支撑系统的设计或改进提供了可靠的理论依据。

HL-2M真空室截面形式及重力支撑的初步分析

利用有限元分析软件ANSYS对不同截面的真空室做静力分析,结果表明圆弧形结构比多边形结构强度好。分别对8、16个重力支撑的真空室做静力分析,得到真空室与重力支撑连接位置的应力变化,优选了真空室重力支撑数量。优化设计了真空室与重力支撑连接位置,使其在烘烤时热应力减小。