江阴市"十四五"水利高质量发展规划的思考

总结江阴市"十三五"水利发展规划在水安全、水资源、水生态、农村水利、水管理服务及水利发展保障等方面的完成情况.分析江阴市水利发展存在的主要短板、问题.围绕建设高质量的水安全保障体系、水资源配置体系、水生态治理体系、水利管理体系、水利服务体系,系统提出江阴市"十四五"水利高质量发展规划思路.     

北京安河泄洪闸金属结构安全检测与评价

水闸安全运行,会受到水工金属结构安全性状影响.京密引水渠安河泄洪闸已投入运行54年.为保障水闸运行安全,需对其金属结构进行全面的安全检测.文章采用多种检测手段对安河泄洪闸金属结构开展现场检测,对结构病害进行梳理,对金属结构的安全状态进行综合评价,为水闸安全运行提供技术支撑.     

Study of the hinge thickness deviation for a 316L parallelogram flexure mechanism fabricated via selective laser melting

3D printing offers great potential for developing complex flexure mechanisms. Recently, thickness-correction factors (TCFs) were introduced to correct the thickness and stiffness deviations of powder-based metal 3D printed flexure hinges during design and analysis. However, the reasons for the different TCFs obtained in each study are not clear, resulting in a limited value of these TCFs for future design and fabrication. Herein, the influence of the porous layer of 3D printed flexure hinges on the hinge thickness is investigated. Samples of parallelogram flexure mechanisms (PFMs) were 3D printed using selective laser melting (SLM) and 316L stainless steel powder. A 3D manufacturing error analysis was completed for each PFM sample via 3D scanning, surface roughness measurement and morphological observation. The thickness of the porous layer of the flexure hinge was independent of the designed hinge thickness and remained close to the average powder particle diameter. The effective hinge thickness could be estimated by subtracting twice the value of the porous layer thickness from the designed value. Guidelines based on finite element analysis and stiffness experiments are proposed. The limitations of the presented method for evaluating the effective hinge thickness of flexure hinges 3D printed via SLM are also discussed.

     

一种外骨骼机器人的光纤转角传感器设计

设计了一种新型的强度调制型光纤传感器,该传感器被应用于外骨骼机器人的智能感知系统,可以测量人体肢体的转动角度;采用双接收光纤光强比值法,并通过对光纤单元的并列排布设计,该传感器具备普通强度调制型光纤传感器的结构简单,性能稳定等优点的同时,能够实现对光源功率波动的自补偿,量程也扩大至0～180°。仿真结果显示,此种光纤传感器具有较好的静态特性。     

一种测量工业环境感应传导干扰的方法

针对采用干扰测量仪或频谱分析仪只能测量工业环境中干扰源的辐射干扰强度的问题,提出了一种测量工业环境感应传导干扰的方法。该方法采用HBYV非双绞2芯线作为干扰接收体,采用数字示波器记录干扰波形的最大幅值和单个脉冲的最大强度,通过与标准干扰发生器感应到HBYV非双绞2芯线上的干扰信号大小进行比较,确定干扰强度。以瞬变脉冲群干扰强度和浪涌干扰强度的测量为例,详细介绍了该方法的具体实现。     

飞机振动特性激光测量与分析

飞机振动特性测量与分析,对于飞机识别和探测系统的设计与评估是至关重要的;在简要介绍了振动特性测量理论之后,针对外场环境条件,设计了飞机振动特性激光测量装置和测量方法,并经过实验室验证;在全尺寸飞机试验与测量过程中,获得了有效的原始测量数据,计算出飞机振动特征量:平均中心频率和二阶中心矩;同时指出了在飞机振动测量中应注意的问题;试验表明,飞机振动特性测量与分析方法正确、有效。     

The research of adaptive sliding mode controller for motor servo system using fuzzy upper bound on disturbances

Considering sliding mode control (SMC) method using the estimation of upper bound on disturbances in motor servo system, if the upper bound is underestimated, the position tracking precision is poor. Contrarily, the control input is overlarge and even chatters violently. To solve the above problems, an adaptive sliding mode controller (ASMC) is proposed. It utilizes a fuzzy decision maker (FDM), which exports the estimation of upper bound on disturbances according to the information of position tracking error and control input. The computer simulations on a dc motor present that the proposed method guarantees satisfactory position tracking accuracy and the chattering at control input is evidently suppressed. Moreover, the output of FDM is sensitive to the changes of disturbances realtimely and precisely. Subsequently, the proposed scheme possesses strong robust performance against disturbances in motor servo system.     

The calcium-phosphorus and the simultaneous calcium-oxygen and calcium-sulfur equilibria in liquid iron

The equilibrium Ca₃P_2(s) = 3[Ca] + 2[P] was studied at 1600 ° by equilibrating liquid iron, saturated with Ca₃P₂, and contained in a TiN crucible, with Ca vapor. The source of Ca was liquid Ca contained in an Mo crucible, and the vapor pressure of Ca was varied by varying the position of the Mo crucible in the temperature gradient of a vertical tube furnace. A least-squares analysis of the data gave and. The simultaneous equilibria CaO_(s) = [Ca] + [O] and CaS_(s) = [Ca] + [S] were studied at 1600 ° by equilibrating liquid iron, contained in a pressed and sintered CaO-CaS crucible with Ca vapor. The advantage of this technique is that two equilibrium constants,K _cas andK _cao, and two interaction coefficients, and can be determined from one set of experiments. It was determined that, at 1600 °,K _cas = 5.9 × 10⁻⁸ K _cao = 5.5 × 10⁻⁹,, and. Formerly Graduate Students     

基于协同观测器的永磁同步电机无传感控制

针对传统滑模观测器使用符号函数引起的抖振问题,提出了一种基于连续函数的协同观测器方法,实现永磁同步电机(PMSM)的无传感控制。首先,研究PMSM的离散数学模型。其次,建立k+1时刻的电流偏差和k时刻的电流偏差之间的函数关系。最后,利用反正切函数计算转子位置并加入角度补偿,提高观测精度。仿真结果表明,所设计的协同观测器不仅无抖振现象,还具有更高的估算精度及良好的抗干扰性能,比传统滑模观测器可以更好地实现PMSM的无传感控制。     

整数值时间序列的拟似然推断

基于推广的负二项稀疏算子利用预设新息过程分布法构造一个一元 INAR(1) 模型,给出了模型的概率性质并利用拟似然估计方法对模型进行了参数估计,同时也考虑了最小二乘法、极大似然估计方法。通过数值模拟评估了这些估计方法的有效性,并应用实际数据给出模型的应用,通过比较得出基于推广的负二项稀疏算子带有几何新息过程的INAR(1)是更适合数据的模型。