大工作阻力放顶煤液压支架结构改进设计

为解决某矿使用的放顶煤液压支架出现支架压死、后立柱爆缸、结构件开裂等问题,通过地质条件分析,探究适应此类地质条件的液压支架改进方法,在此基础上,将现用液压支架架型由ZF15000/26/42改进为ZF21000/25/45D,并对支架整体结构进行针对性优化,以矿压监测数据为边界条件,对整架进行有限元分析。经样机研制及批量工业性试验,结果表明该支架架型布局及局部结构适应此类地质条件的综放开采,丰富了具备此类地质条件的综放开采液压支架应用案例。     

Structural parameter design method for a fast-steering mirror based on a closed-loop bandwidth

When a fast-steering mirror (FSM) system is designed, satisfying the performance requirements before fabrication and assembly is vital. This study proposes a structural parameter design approach for an FSM system based on the quantitative analysis of the required closed-loop bandwidth. First, the open-loop transfer function of the FSM system is derived. In accordance with the transfer function, the notch filter and proportional-integral (PI) feedback controller are designed as a closed-loop controller. The gains of the PI controller are determined by maximizing the closed-loop bandwidth while ensuring the robustness of the system. Then, the two unknown variables of rotational radius and stiffness in the open-loop transfer function are optimized, considering the bandwidth as a constraint condition. Finally, the structural parameters of the stage are determined on the basis of the optimized results of rotational radius and stiffness. Simulations are conducted to verify the theoretical analysis. A prototype of the FSM system is fabricated, and corresponding experimental tests are conducted. Experimental results indicate that the bandwidth of the proposed FSM system is 117.6 Hz, which satisfies the minimum bandwidth requirement of 100 Hz.     

宽频带梯形叉指式换能器优化设计及应用

由声表面波（Surface Acoustic Wave）器件发展而来的叉指换能器（Interdigital Transducer，IDT）由于其工作频率可以设计、频带宽可调、损耗低等特点逐步应用于结构健康监测（Structural Health Monitoring，SHM）系统中，因此在智能材料与结构中有着广泛的应用前景。本文针对现有矩形IDT带宽窄的不足，研究宽频带梯形叉指换能器（Trapezoidal Interdigital Transducer，TIDT）。采用有限元分析方法对TIDT的尺寸进行结构优化设计，并对设计的TIDT进行性能测试，通过实验研究了TIDT用于结构损伤检测的初步应用。实验结果表明，TIDT在实际应用中进一步提高了损伤识别精度，具有广泛的应用前景。     

以物理气相传输法自支撑生长氮化铝单晶的表征

本文提出了以物理气相传输法自支撑生长氮化铝单晶的新方法，此方法可以在氮化铝烧结体表面一次性获得大量生长的氮化铝单晶。本研究中，在2373–2523 K的温度条件下经过100 h生长的氮化铝单晶，其最大尺寸为7 × 8 × 12 mm3，典型直径为5–7 mm。这些原生晶体的表面形貌及结晶质量分别通过扫描电子显微镜、拉曼光谱和高分辨X射线衍射进行表征分析。其中，拉曼光谱E2峰位的半高全宽为5.7 cm-1，高分辨X射线衍射得到的对称摇摆曲线的半高全宽为93.6角秒。经过选择性化学腐蚀后的晶体，其表面的平均腐蚀坑密度为7.5 × 104 cm-2。逸出气体分析和辉光放电质谱分析结果表明，碳和氧为晶体内部的主要杂质元素，含量分别为28 ppmw和120 ppmw。此方法为高质量氮化铝单晶的获取提供了一个新的途径，这些单晶可以被切成晶片作为后续氮化铝同质外延生长的优良籽晶。使用这些小的籽晶，我们首次成功制备出了直径高达60 mm的氮化铝单晶体/晶圆，并具有良好的深紫外光透过性。     

通用型液压马达实验台的分析与设计

通用型液压马达实验台的检测实验装置能够模拟实际工况对不同类型、多种规格的液压马达进行性能测试。设计一种通用型液压马达,包括实验台的连接支架设计、转速扭矩仪选型、负载系统设计、油箱设计及油路优化,并对设计参数进行了计算与有限元验证。该实验台可按照国家标准和检测方法,对多种类型不同型号液压马达做性能测试。     

基于PMAC的航空结构件柔性工装分布式控制系统设计

航空结构件是航空飞行器中的重要组成部分，航空结构件的自动化柔性工装质量直接影响航空飞行器的飞行安全水平。为降低系统位置和姿态控制误差，减小航空结构件的磨损面积，设计了基于PMAC的航空结构件柔性工装分布式控制系统。采用PMAC运动控制器，接收电子部件的反馈信号，控制步进电机、直流电机和交流电机。结合工控机、定位器、伺服电机和分布式通信网络，完成硬件系统的设计。根据航空结构件柔性工装操作设备的组成结构和工作原理，构建相应模型。确定航空结构件在目标曲面上的柔性工装位置，从移动位置和装配力两个方面，计算柔性工装控制量。在PMAC控制器的作用下，通过位姿的调整实现系统的航空结构件柔性工装分布式控制功能。系统测试结果表明，设计分布式控制系统的位置和姿态控制误差分别降低了13cm和0.32°，且设计系统控制下航空结构件的磨损面积较小。     

缺水传感器改进设计

针对一种煤矿用本安型缺水传感器在现场安装及维护难度大,以及抽采泵供水状态下管道内有水但传感器检测显示为无水,或抽采泵停止工作时传感器检测显示有水问题,分析原产品中磁体及探头感应装置结构。改进其结构形式,并优化安装,使检测稳定可靠。实现抽采泵管道用缺水传感器的可靠性设计和轻量化设计。     

A coupled and interactive influence of operational parameters for optimizing power output of cleaner energy production systems under uncertain conditions

The mechanisms in proton‐exchange membrane fuel cells (PEMFCs) cannot be explicitly represented by a mathematical function because the PEMFC system is multi‐dimensional and complex and represents uncertainty in operation variables, which cannot be modeled by experiments or by trial‐and‐error approach. Therefore, this work proposes to study the coupled and interactive influence of stack current (SC), stack temperature (ST), oxygen excess ratio (OER), hydrogen excess ratio (HER), and inlet air humidity (IAH) for optimizing the power output of PEMFC. The data obtained from the experiments have been inserted into architecture of automated neural‐network search, which automates the selection of error function, activation function, uncertainties in inputs and number of hidden neurons in formulation of a robust and accurate model for power density as a function of five operational variables. Among the operational variables, the correlation coefficient between the SC and the output power is the highest, followed by OER, and the ST. However, for HER and IAH, the power output follows negative nonlinear relation. The optimization converged at 130^th iteration results in maximum power output of 3410 W for an optimum value of SC (51A), ST (59°C), OER (3:2), HER (1:10), and IAH (0.8).