双耦合直驱力矩电机自适应RBF网络反演控制策略研究

电机作为机械手臂的核心元器件,已成为现代工业应用研究必不可少的技术,而双电机协同运动一直是该研究领域的一大热点.因此为解决多电机协同运动、精确位置跟踪和抗干扰等问题,以当下热门的直驱力矩电机组成双耦合电机系统作为研究对象;首先,进行了精确模型下的反演控制器设计和稳定性分析,证明所设计控制律稳定;其次,在未知模型下进行RBF网络反演控制器的设计,通过Lyapunov稳定性证明得到所设计系统稳定可靠;最后,以未知模型下的自适应RBF网络反演控制器为例,进行MTALAB/Simulink仿真分析可知:所设计控制器实现能够较好的位置跟踪、响应速度快,具有很好的应用研究价值.     

基于滑模的空中加油受油机会合制导与控制

为实现空中加油过程中受油机与加油机自主会合,建立满足会合要求的滑模控制面,设计相应制导律.根据受油机与加油机相对位置与速度得出受油机前向加速度指令.基于六自由度受油机动力学模型,采用时标分离将受油机的角运动系统分为快慢回路,采用动态逆方法分别进行系统设计和设计满足追踪会合要求的速度控制律,并以无人机自主跟踪加油机实现会合为例进行仿真.结果表明:该系统能引导受油机实现与加油机的会合,具有良好的动态性能.     

Fish-scale-like nano-porous membrane based on zeolite nanosheets for long stable zinc-based flow battery

Zinc-based flow batteries receive widespread attention due to their advantages of low cost and high energy density. However, zinc dendrites are easy to appear during the charge process, pierce the membrane and thus destroy the battery, which seriously restrict its further development. In this article, MFI-type zeolite nanosheets (ns-MFIs) with high mechanical strength and hydrophobicity are in situ introduced to porous polymer membranes, which spontaneously form turnup fish-scale-like structure through the one-step phase inversion/surface segregation process. This special structure well disperses mechanical energy to provide effective protection characteristics to resist the penetration of zinc dendrites, and meanwhile promotes the uniform zinc depositions on the electrode by alleviating the water migration and accelerating zincate ion diffusion, so as to prolong the cycle life of the battery for more than 600 cycles, which is 4 times and 2.5 times longer than the commercial Nafion 212 and pristine porous polymer membrane, respectively. Moreover, the sub-nano size pores and high-aspect-ratio of ns-MFIs afford membranes extra ion sieving ability and transport area for the charging-balancing ions OH⁻ to ensure superior battery performance, delivering an average coulombic efficiency (CE) of ~98.5%, voltage efficiency (VE) of ~83.2%, and energy efficiency (EE) of ~81.9% at 80 mA/cm².     

重力异常变密度界面深度反演方法对比

界面深度反演是重力异常定量地质解释的常用方法,学者们针对界面反演问题提出了多种经典算法。以密度随深度变化的直立长方体为基本单元搭建了合成模型,在此基础之上对比了经典的Bott法与非线性反演方法,分析了它们各自的特点和适用环境。模型试验表明:1)Bott法所需要的迭代次数比非线性反演多;2)界面节点个数较少时,非线性反演与Bott法所需计算时间接近,界面节点较多时,Eott法所需计算时间明显小于非线性反演;3)二者反演效果接近。在实际勘探中,需要根据不同客观条件选择具体的界面深度反演方法。     

基于非线性动态逆的水下运载器控制方法研究

针对水下运载器具有强非线性、强耦合、多输入多输出、水动力作用复杂以及姿态变化剧烈等特点,设计了一种非线性动态逆控制系统,解决了传统控制器设计方法在线性化过程中因忽略非线性因素带来局限性的问题。通过慢回路姿态控制器和快回路姿态控制器的设计解决了水下运载器非线性、强耦合以及多输入多输出的问题,并且运用Lyapunov 稳定性分析证明了控制器的稳定性。控制方法跟踪单位阶跃信号时稳态时间为1 s,超调量为4%,较PID 控制的动态特性有较大提升。非线性控制系统仿真结果表明该控制器对于依30%水动力参数不确定性具有一定的鲁棒性。摇摇     

基于动态逆与QFT 的鲁棒飞行控制器

针对保证无人战斗机控制器的解耦性能和鲁棒性能问题,设计一个某无人战斗机的姿态控制器。将动态逆(DI)和定量反馈理论(QFT)相结合,用动态逆实现无人战斗机控制的动态解耦,用定量反馈理论保证控制器的鲁棒性能,并以实例进行仿真结果分析。仿真结果表明:在气动数据变化±30%的范围内,DI与QFT控制器可以实现对飞机姿态的精确控制,能很好地解决飞机的姿态控制问题,有较好的工程应用价值。     

Ethanol‐responsive characteristics of polyethersulfone composite membranes blended with poly(N‐isopropylacrylamide) nanogels

Ethanol‐responsive smart membranes with different microstructures are prepared from blends of polyethersulfone (PES) and poly(N‐isopropylacrylamide) (PNIPAM) nanogels by immersion precipitation phase inversion method in a convenient and controllable manner. The introduction of PNIPAM nanogels forms the microporous structures on the surface of the top skin layer and on the pore walls of the finger‐like porous sublayer of membranes. The ethanol‐responsive characteristics of the proposed PES composite membranes are systematically investigated. With increasing ethanol concentration in the range from 0 to 15 wt %, the trans‐membrane flux of ethanol solution increases. The microstructures and the resultant ethanol‐responsive characteristics of the composite membranes can be regulated by the content of PNIPAM nanogels blended in the membranes. The more the content of PNIPAM nanogels blended in the membranes, the more the number of the submicron pores is, and thus the better the ethanol‐responsive characteristics of the composite membranes. The proposed ethanol‐responsive smart membranes are expected to be combined with the traditional pervaporation membranes as a smart vavle to achieve continuous and highly efficient ethanol production during the biological fermentation. The preparation technique and results in this study provide valuable guidance for further design and the industrial‐scale fabrication of novel composite membranes for application in ethanol separation systems. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41032.     

Pickering乳液研究进展

Pickering乳化剂是指用固体颗粒代替传统的化学乳化剂,固体颗粒在分散相液滴表面形成一层薄膜阻止了液滴之间的聚集,在造纸、乳液聚合、化妆品、药物缓释和制备功能高分子领域具有应用前景。本文从Pickering乳化剂的作用机理、乳化稳定因素、相转化以及应用几个方面进行总结。     

Dieterici气体对比态形式的转换温度

运用对比态形式的Dieterici状态方程,分析和导出焦-汤效应的对比转换温度与对比压强关系式,并且通过Matlab软件绘制Dieterici方程在不同温度指数的对比转换曲线,将其与Miller方程的对比转换曲线进行比较分析。