基于奖励引导的六足机器人自主步态学习

为提高机器人自主学习能力,提出一种基于奖励引导的机器人自主步态学习算法.首先给出自主设计的机械式步态同步六足机器人的机械结构,其独特的多层钢堆叠腿部设计方案和特有的机械同步传动方案为机器人后续步态学习研究奠定良好基础;接下来提出一种基于奖励引导的机器人步态学习算法,该算法可以让机器人在未知环境中进行技能学习;最后,在MATLAB和ADAMS联合仿真平台上进行算法验证实验,实验结果显示以速度和高度分别为主评价指标会呈现出2种合理的收敛结果,且在该算法下六足机器人可以自主学习到翻越木块的高难度技能.     

一起110 kV变压器故障原因分析

针对一起110 kV主变调压线圈匝间短路引起的跳闸故障进行原因分析,通过电气试验及解体检查,确认故障原因为调压前故障部位匝间绝缘已有破损,7挡调到6挡后匝间电压差增大,在140 h内加速了匝间绝缘的电气性损伤,最终导致B相调压线圈故障,最后提出了相关解决措施.     

SiO2改性聚丙烯纤维棉对油水乳状液的高效分离

近年来,基于特殊润湿性理论制备表面具有微纳米粗糙结构的多孔材料成为油水分离领域研究的重点。为了满足不同环境下对不同形式油-水乳状液高效高通量分离的需求,该研究利用纳米SiO2颗粒对聚丙烯（PP）纤维棉有针对性地亲（疏）水改性,构建了系列不同润湿性和粗糙度的PP纤维棉,探究了不同孔隙度和表面能的PP纤维棉对W/O及O/W型乳状液的分离性能,结果表明,经过亲（疏）水改性后的PP纤维棉对水/正己烷和水/甲苯乳状液的分离效率都高于99.5%,通量高于700 L/(m2·h),并针对不同形式油-水乳状液阐释其相应的分离机制,为后续油-水乳状液分离材料的科学设计和可控制备提供了理论依据。     

计及风电高频保护的送端电网多直流协同频率控制

为解决中国能源与负荷逆向分布问题,大量高压直流输电工程正在建设或已经投运。针对送端电网中可能发生的直流闭锁导致的高频事件,计及风电机组的高频保护约束,研究了进行多回直流协同控制从而抑制电网频率偏移的方法,提出了以各健全直流总功率调制量最小为目标的多直流协同频率控制模型,通过一阶差分近似求解系统最大频率偏移相对于各受控直流功率的灵敏度,优化求解多直流协同频率控制策略。并进一步以某含高比例风电的送端电网为例,验证该方法在送端电网频率控制策略整定中的有效性。     

Ultra-Stretchable Monofilament Flexible Sensor with Low Hysteresis and Linearity based on MWCNTs/Ecoflex Composite Materials

Wearable human–computer interaction equipment is a common technology, which can improve the comfort, convenience, and safety of the human body, and also can monitor human health. The flexible and wearable tensile sensor can be conveniently installed on clothes or directly connected to the body. This provides a convenient, timely, and portable solution for the detection of human motion. Therefore, wearable electronic equipment is gaining more attention. In this paper, a highly stretchable, flexible, and sensitive strain sensor which is based on multi-walled carbon nanotubes/Ecoflex nanocomposites is reported. A monofilament tensile sensor obtains good linearity (10.77%), low hysteresis (1.63%), good stability (6000 cycles under 100% strain), and ultra-high strain range (ε = 1300%). This ultra-stretchable sensor has potential applications in human motion monitoring, medical rehabilitation, health monitoring, human–computer interaction, and soft robots.     

Low Dielectric Polyimide/Fluorinated Ethylene Propylene (PI/FEP) Nanocomposite Film for High-Frequency Flexible Circuit Board Application

The low dielectric polymer films have drawn great attention to the application as the dielectric insulating materials in high-frequency circuit boards, while the weak adhesion to the copper foils and the poor processability resulted from the fluorinated or rigid structures limited their high-frequency application. In this work, the low dielectric and high adhesive polyimide/fluorinated ethylene propylene (PI/FEP) nanocomposite film for high-frequency flexible circuit board application is developed. It is indicated that the fluorocarbon surfactants can significantly improve the dispersion of FEP in PI substrate, and thus, the PI/FEP nanocomposite film exhibits excellent mechanical properties, including the tensile strength increases to 46.6 MPa and the elongation at the break increases to 13.7%. Importantly, at the high-frequency of 10 GHz, the 60 wt% FEP filled PI nanocomposite film displays an ultralow dielectric loss (0.006) and a reduced dielectric constant (2.69). In addition, the high-frequency flexible circuit board with the PI/FEP film as the dielectric insulating layer has a high peel strength of 0.75 N mm⁻¹, indicating this PI/FEP nanocomposite film can meet the requirements of the high-frequency flexible circuit board application.     

LY12铝合金中温钎焊技术

采用改进的KF—CsF—A1F3中温无腐蚀钎剂与Ag—A1—Cu—Zn中温钎料实现了对LYl2铝合金的中温钎焊，钎焊接头的抗剪强度可达到母材强度的80％，对接接头钎缝的抗拉强度可达到母材强度的70％，突破了”热处理强化铝合金通常不能钎焊”的传统论断。     

高强度钢腐蚀疲劳裂纹扩展的温度效应和过载迟滞效应

通过在18,35和55℃蒸馏水中疲劳裂纹扩展试验,证明了超高强度钢30CrMnSiNi2A腐蚀疲劳具有强烈的温度效应,得到了ΔK值和温度对裂纹扩展速率影响的复合表达式。由于扩展速率数据拟合得到的表观激活能值(36.7kJ/mol)十分接近于氢在γ-Fe中的扩散激活能值,支持了氢助裂纹扩展的观点。对大气中疲劳裂纹扩展具有重要价值的过载迟滞效应,在腐蚀疲劳时显著地减小,在0.1Hz的低频率下尤其明显。     

EFFECTS OF DYNAMIC STRAIN-AGING AND DEFORMATION TWINNING ON THE MECHANICAL PROPERTIES OF BRASS H68

研究了动态应变时效和形变孪晶对具有低堆垛层错能的面心立方合金H68黄铜(Cu-32wt-%Zn)拉伸时机械性能的影响.试验是在196—623K温度范围内进行的,应变速率为4.9 x 10~(-4)s~(-1),平均晶粒尺寸为0.05mm.结果表明,该合金在不同温度下静拉伸,其最大均匀应变量,面缩率及形变孪晶体积分数,均以相似的规律,随温度的降低而升高,且在某一定的温度区间,出现一个加工硬化的平台.本试验的另一重要结果是,形变李晶对机械性能的影响,可延续到400K以上,和动态应变时效的作用有一定的重迭.因此,在某一温度区间(如从333—400K),材料机械性能的改变,应是这两种因素综合作用的结果.