Variants of Secondary Control with Power Recovery for Loading Hydraulic Driving Device

Current high power load simulators are generally incapable of obtaining both high loading performance and high energy efficiency. Simulators with high energy efficiency are used to simulate static-state load, and those with high dynamic performance typically have low energy efficiency. In this paper, the variants of secondary control（VSC） with power recovery are developed to solve this problem for loading hydraulic driving devices that operate under variable pressure, unlike classical secondary control（CSC） that operates in constant pressure network. Hydrostatic secondary control units are used as the loading components, by which the absorbed mechanical power from the tested device is converted into hydraulic power and then fed back into the tested system through 4 types of feedback passages（FPs）. The loading subsystem can operate in constant pressure network, controlled variable pressure network, or the same variable pressure network as that of the tested device by using different FPs. The 4 types of systems are defined, and their key techniques are analyzed, including work principle, simulating the work state of original tested device, static operation points, loading performance, energy efficiency, and control strategy, etc. The important technical merits of the 4 schemes are compared, and 3 of the schemes are selected, designed, simulated using AMESim and evaluated. The researching results show that the investigated systems can simulate the given loads effectively, realize the work conditions of the tested device, and furthermore attain a high power recovery efficiency that ranges from 0.54 to 0.85, even though the 3 schemes have different loading performances and energy efficiencies. This paper proposes several loading schemes that can achieve both high dynamic performance and high power recovery efficiency.

Discuss about the Driving Device Suspension Mode of Locomotive

分析了机车驱动装置悬挂方式对轮轨在垂向动作用力的影响，介绍机车驱动装置悬挂方式主要结构和技术特点，说明了不同驱动装置悬挂方式在机车的运用。

Performance Improvement of the LM Device and Its Application to Precise Measurement of Motion Trajectories within a Small Range with a Machining Centre

In order to apply the LM device previously developed to precisely measuring small motion trajectories located on the different motion planes, three major improvements are successfully performed under the condition of completely maintaining the advantages of the device. These improvements include 1) development of a novel connection mechanism to smoothly attach the device to the spindle of a machining centre;2) employment of a new data sampling method to achieve a high sampling frequency independent of the operating system of the control computer;and 3) proposal of a set-up method to conveniently install the device on the test machining centre with respect to different motion planes. Practical measurement experiment results with the improved device on a machining centre sufficiently demonstrate the effectiveness of the improvements and confirm several features including a very good response to small displacement close to the resolution of the device, high precision, repeatability and reliance. Moreover, based on the measurement results for a number of trajectories for a wide range of motion conditions, the error characteristics of small size motions are systematically discussed and the effect of the movement size and feed rate on the motion accuracy is verified for the machining centre tested.

Direct Yaw Moment Control for Distributed Drive Electric Vehicle Handling Performance Improvement

For a distributed drive electric vehicle（DDEV） driven by four in-wheel motors, advanced vehicle dynamic control methods can be realized easily because motors can be controlled independently, quickly and precisely. And direct yaw-moment control（DYC） has been widely studied and applied to vehicle stability control. Good vehicle handling performance： quick yaw rate transient response, small overshoot, high steady yaw rate gain, etc, is required by drivers under normal conditions, which is less concerned, however. Based on the hierarchical control methodology, a novel control system using direct yaw moment control for improving handling performance of a distributed drive electric vehicle especially under normal driving conditions has been proposed. The upper-loop control system consists of two parts： a state feedback controller, which aims to realize the ideal transient response of yaw rate, with a vehicle sideslip angle observer; and a steering wheel angle feedforward controller designed to achieve a desired yaw rate steady gain. Under the restriction of the effect of poles and zeros in the closed-loop transfer function on the system response and the capacity of in-wheel motors, the integrated time and absolute error（ITAE） function is utilized as the cost function in the optimal control to calculate the ideal eigen frequency and damper coefficient of the system and obtain optimal feedback matrix and feedforward matrix. Simulations and experiments with a DDEV under multiple maneuvers are carried out and show the effectiveness of the proposed method： yaw rate rising time is reduced, steady yaw rate gain is increased, vehicle steering characteristic is close to neutral steer and drivers burdens are also reduced. The control system improves vehicle handling performance under normal conditions in both transient and steady response. State feedback control instead of model following control is introduced in the control system so that the sense of control intervention to drivers is relieved.

Integrated System of Solar Cells with Hierarchical NiCo2O4 Battery-Supercapacitor Hybrid Devices for Self-Driving Light-Emitting Diodes

An integrated system has been provided with a-Si/H solar cells as energy conversion device,NiCo2O4 battery-supercapacitor hybrid(BSH)as energy storage device,and light emitting diodes(LEDs)as energy utilization device.By designing three-dimensional hierarchical NiCo2O4 arrays as faradic electrode,with capacitive electrode of active carbon(AC),BSHs were assembled with energy density of 16.6 Wh kg-1,power density of 7285 W kg-1,long-term stability with 100% retention after 15,000 cycles,and rather low self-discharge.The NiCo2O4//AC BSH was charged to 1.6 V in 1 s by solar cells and acted as reliable sources for powering LEDs.The integrated system is rational for operation,having an overall efficiency of 8.1% with storage efficiency of 74.24%.The integrated system demonstrates a stable solar power conversion,outstanding energy storage behavior,and reliable light emitting.Our study offers a precious strategy to design a self-driven integrated system for highly efficient energy utilization.

Improvement of Metal-Graphene Ohmic Contact Resistance in Bilayer Epitaxial Graphene Devices

We report on an improved metal-graphene ohmic contact in bilayer epitaxial graphene on a SiC substrate with contact resistance below 0.1 Ω.mm. Monolayer and bilayer epitaxial graphenes are prepared on a 4HoSiC substrate in this work. Their contact resistances are measured by a transfer length method. An improved photoresist-free device fabrication method is used and is compared with the conventional device fabrication method. Compared with the monolayer graphene, the contact resistance Rc of bilayer graphene improves from an average of 0.24Ω·mm to 0. 1 Ωmm. Ohmic contact formation mechanism analysis by Landauer＇s approach reveals that the obtained low ohmic contact resistance in bilayer epitaxial graphene is due to their high carrier density high carrier transmission probability, and p-type doping introduced by contact metal Au.

高压断路器操动机构驱动电机及其控制技术研究

高压断路器操动机构用电机驱动提高了断路器运行的可靠性与可控性,因此设计了一套适用于126 kV真空断路器的电机操动机构。基于操动机构动力学分析结果确定驱动电机转矩、转速要求,提出一种有限转角永磁无刷电机设计方案,研制样机进行联机试验完成动作要求检验。在此基础上,设计分段转矩控制策略,结合驱动电机输出转矩需求将操动机构的运动过程分为4个阶段,从降低触头碰撞、避免预击穿现象发生、提高断路器工作可靠性角度对各阶段电机输出转矩进行动态调节。结果表明:所研制的驱动电机配合分段转矩控制策略,在保证灭弧室对操动机构动作时间、动作速度要求的前提下,实现了操动机构的运动过程优化和工作可靠性提高,促进了断路器智能化操作进程。

有限理性决策理论下驾驶信息过载研究及应用

随着汽车网联化和智能化的发展,汽车驾驶过程面临着车内外多源信息过载的影响,这可能会产生交通安全问题.驾驶信息过载包含感知、认知和决策等复杂神经机制.在知识、时间和精力有限的情况下,当驾驶员处于庞大、繁杂、多变环境中排查信息对象并进行决策时,决策都是在有限度的理性条件下进行,且常带有主观因素,这是有限理性决策理论的基本原理.汽车工业界基于有限理性决策理论,根据人的特性研究了AR-HUD控制驾驶信息过载的汽车驾驶辅助技术以及OLED车载显示的应用,驾驶员在面临信息过载时可快速筛选关键信息,做出正确驾驶决策,以此来提升驾驶的安全性.本文通过综述国内外学者在驾驶信息过载原因、生理心理机制以及控制驾驶信息过载的技术和装备等方面的研究成果,为安全驾驶、汽车智能化发展的产学研结合提供参考.

基于激光加工的微安保机构设计与性能

复杂场景下火工品微安保机构需具有可恢复与抗过载特性,为此,研究设计了基于激光加工的金属材质电热驱动微安保机构,采用有限元模拟分析了镍基微电热执行器动作特性,通过调整双热臂U型电热执行器热臂和冷臂的长度、宽度以及各臂之间的间隙,探究它们对输出位移的影响;通过正交实验得到优化的超快激光加工工艺参数分别为频率100 kHz、能量113μJ、切割速度100 mm·s^(-1),实现了镍基电热微安保机构的超快脉冲激光精确制造;最后,搭建了安保机构性能验证平台,验证了该机构在不同电流激励下的驱动位移与隔爆性能。结果表明,在8 A激励电流下,加工的镍基微安保机构驱动位移可达1084μm,所组装的火工品微安保机构在传爆序列中能够有效隔爆。

纤维包自动除带及拆袋机抱夹装置静力学仿真分析

为降低工人劳动强度,实现面向直行往复式自动抓棉机的纤维包自动化搬运与排放,在所设计的基于自动导向车(AGV)的抱夹车结构基础上,使用ANSYS Workbench对抱夹车的抱夹装置、抱夹支撑装置及其整体进行了静力学仿真分析,得到了各主要机构的最大应力所在位置和最大应力的数值,以及装置在约束下的最大变形量。经分析,抱夹爪最大应力发生在夹爪根部,为57.26 MPa,结构优化后的抱夹爪驱动机构最大应力为217.26 MPa,抱夹车最大变形量为3.0269 mm,最大应力发生在下支撑架上与上部滚轮接触的位置,为108.28 MPa,均满足材料强度要求。该研究验证了抱夹装置结构的强度与刚度,对不符合工作要求的薄弱构件进行了改进设计,确保了装置在实际工况下工作的可靠性与稳定性。

透雕滤棒成型喷嘴装置仿真分析及改进设计

为解决传统拉丝成型滤棒截面成型受限问题,对透雕滤棒成型喷嘴装置进行仿真分析及改进设计研究。基于计算流体力学(Computational Fluid Dynamics,CFD)仿真软件,对3类典型的透雕滤棒成型喷嘴结构的蒸汽流速和温度进行模拟分析,得到透雕滤棒喷嘴成型过程的流体力学变化规律,试验结果表明:倾斜环状分布式喷嘴的综合性能最佳,改进透雕滤棒成型喷嘴装置的结构设计,使其成型效率得到有效提高,为工业成型装备领域的分析与改进提供参考。

基于便携式粗糙度仪的表面轮廓测量实验平台设计

该文基于便携式粗糙度仪设计了一种用于采集工件表面轮廓数据的测量实验平台,并同步开发轮廓分析软件。该测量实验平台由三轴移动装置、夹具、轮廓数据采集装置(粗糙度仪)及计算机组成,可采集水平方向上0.3~16.0 mm、垂直方向上–200~200μm复杂表面的轮廓数据,用于微结构或非球面等面型的测量实验。基于MATLAB软件设计模块开发了轮廓数据处理及分析软件,与金相显微镜及泰勒霍普森轮廓仪所测量的轮廓数据结果对比,该测量实验平台的测量误差低于5%,证明该平台及测量方法的可靠性和准确性。

自动扶梯选型故障分析

自动扶梯的运行质量至关重要,该文通过介绍自动扶梯的选型、土建的勘测处理、安装与维护过程中的故障实例,从技术角度对案例进行分析,保障扶梯的安全可靠运行,提供舒适的乘坐体验。

间隔装药的殉爆起爆技术在露天矿山爆破中的应用

为了降低西沟露天石料厂的采石爆破成本,提高经济效益;应用空气袋间隔装药装置技术进行了150 mm炮孔和100 mm炮孔的爆破实验对比,同时进行了露天炮孔孔内反向和正向起爆殉爆试验对比。结果表明:采用炮孔中部空气袋间隔装置的露天矿台阶爆破,电子雷管起爆一端装药之后再利用其爆轰波殉爆起爆另一端装药,孔径大的炮孔比孔径小的炮孔殉爆起爆的爆破效果好;采用殉爆起爆技术后,做到了节能减排和提效;反向起爆爆破法与正向起爆爆破法相比,爆破效果更好。

农田沙化土壤改良机设计及其搅拌效果数值模拟

土壤沙化问题是目前我国制约农业发展的因素之一。设计一款农田沙化土壤改良机,利用SolidWorks建立其整机模型,针对其关键部件搅拌筒建立离散元模型,并使用EDEM软件进行离散元分析,以搅拌轴旋转速度、旋转方向和搅拌时长为试验因素,以土壤和改良液混合均匀程度为优化指标,分析改良装置搅拌筒工作情况。通过正交仿真试验结果得出:最优参数为搅拌架旋转速度40 r/min、搅拌时间15 s、两搅拌架转动方向相反时,其搅拌均匀度为92.61%,变异系数为0.0749。

基于遥感生态指数改进模型的沱江流域生态环境质量时空变化及驱动力研究

[目的]沱江流域面临严重的水土流失、水环境污染和土壤侵蚀等生态环境问题,开展流域生态环境质量评价对推动长江上游生态环境保护和流域社会经济高质量可持续发展具有重要意义。[方法]基于谷歌地球引擎平台,选取2000-2020年的Landsat遥感影像,以绿度、湿度、热度、干度、生物丰度指数构建生态环境质量评价模型,采用变异系数、一元线性回归和空间自相关分析方法对流域内生态环境质量的时空演变格局进行分析,并运用最优参数地理探测器模型(optimal parameter geographic detector model,OPGD)对其驱动力进行探测。[结果](1)2000-2020年,沱江流域生态环境质量多年平均值为0.66,等级以良为主,占比为63.01%。成都周边区县、内江、自贡、泸州等城镇地区生态环境质量较差,呈现南北低中间高的空间分布格局。(2)沱江流域生态环境质量总体呈下降趋势,生态环境质量变差的趋势显著,轻微退化和显著退化面积占比分别为19.75%和5.88%。人口密度大,社会经济发展水平高的城镇化地区,生态环境质量以较高波动为主,占比为18.15%。(3)2000-2020年沱江流域全局自相关莫兰指数范围为0.769~0.870,主要分布在第1象限和第3象限,局部自相关的高-高集聚区和低-低集聚区范围随时间呈显著变化,景观斑块破碎化明显。(4)OPGD结果表明,土地利用类型、坡度、高程、夜间灯光为流域生态环境质量变化的主要驱动因子,人口密度、气温和GDP为次要驱动因子,降水量和坡向因子影响较小。土地利用类型与其他因子交互作用增强对流域内生态环境质量变化的影响。[结论]改进的遥感生态指数模型对开展区域生态环境质量评价提供新方法,研究结果为生态环境保护提供参考。

持续质量改进预防手术室医疗器械相关性压力性损伤的效果

目的探讨持续质量改进在手术室医疗器械相关性压力性损伤中的预防效果。方法选择2022年3月—2023年2月南方医科大学第七附属医院接收的200例手术患者为研究对象,按照入院时间先后顺序分组,各100例,2022年3—8月收治的患者为对照组,2022年9月—2023年2月收治的患者为观察组。对照组采用常规方式进行管理,观察组采用持续质量改进的方式进行管理。对比2组手术室医疗器械相关性压力性损伤的发生率,分析2组患者的住院时间以及手术时间差异。结果观察组手术室医疗器械相关性压力性损伤的发生率为2.00%,低于对照组的17.00%,差异有统计学意义(P<0.05)。观察组患者的住院时间以及手术时间短于对照组,差异有统计学意义(P<0.05)。结论采用持续质量改进在手术室医疗器械相关性压力性损伤预防的过程中,能降低患者出现手术室医疗器械相关性压力性损伤的发生率,缩短患者的手术时间以及住院时间。

改良血浆置换装置在血浆置换术中的应用研究

分析改良血浆置换装置在血浆置换术中的应用效果.选取梧州市红十字会医院2021年2月-2023年10月收治的90例行血浆置换术的患者为研究对象,采用随机数字表法将患者分为3组,分别为对照1组、对照2组、研究组.对照1组应用透析机进行血浆置换,对照2组应用连续肾脏替代治疗机进行血浆置换,研究组应用改良血浆置换装置在灌流机上进行血浆置换.对比3组患者相关指标.结果显示,研究组患者的低血压发生率低于对照1组、对照2组,医疗费用少于对照1组和对照2组(P<0.05);研究组患者的焦虑总发生率低于对照1组和对照2组(P<0.05);研究组患者躯体功能评分、社会功能评分、心理功能评分、物质生活状态评分均高于对照1组、对照2组(P<0.05).研究发现,应用改良血浆置换装置在灌流机上进行血浆置换可显著降低患者低血压的发生率,减少治疗费用,可减轻患者焦虑程度,提高患者生活质量,辅助治疗效果显著.

多工况下的液驱多维力加载装置主轴速度控制

不同工况引起加载力之间的耦合效应降低了速度控制效果,为了更加精准控制不同工况下的主轴速度,提出一种多工况下的液驱多维力加载装置主轴速度控制方法。计算多工况下的液驱多维力加载装置主轴速度,以此作为控制器设计输入。在多种工况下,将液驱多维力加载装置主轴输入和输出速度之间的差值作为输入信号,通过模糊推理算法改进经典PID控制器,通过模糊检测调整改进后的控制器组建模糊自适应PID控制器,实现速度自适应控制。通过实验测试证明,所提方法可以精准地完成液驱多维力加载装置主轴速度控制,受工况影响较小。

热驱动煤矸石碳氧化过程及产物土壤性能研究

针对煤矸石本身所含的碳基矿物,本研究对煤矸石进行中低温微氧化,研究温度、时间对碳基矿物转化效率的影响,阐明煤矸石所含碳基组分向腐殖质转化的过程机理.研究表明,中低温(150~180℃)氧化1~3h后,煤矸石热氧化产物中溶解性有机碳含量提升20倍以上,由8.76mg/L提升至176.72mg/L,有机碳比例可提升5倍,由1.2%提升至6%以上,有机质养分水平类似土壤普查养分分级中的1级土.有机碳提升的原因是热氧化过程使碳基矿物的C-C、C=C键向C=O键转变形成羧基、羟基等官能团,碳基矿物发生氧解向富里酸等腐殖类物质转化.腐殖酸含量的提升可有效改良煤矸石风化产物的保墒及团聚性能,使产物持水率超过砂质土壤标准,从而显著提升冬牧70的生物量.