Driving concepts for bundled ultrasonic linear motors

Several positioning tasks demand translatory drive instead of rotary motion. To achieve drives that are capable, e.g., to drive the sunroof of a car or to lift a car’s window, multiple miniaturized motors can be combined. But in this case many other questions arise: The electromechanical behavior of the individual motors differs slightly, the motor characteristics are strongly dependent on the driving parameters and the driven load, many applications need some extra power for special cases like overcoming higher forces periodically. Thus, the bundle of motors has to act well-organized and at last controlled to get an optimized drive that is not oversized and costly.     

Multi-degree-of-freedom ultrasonic motors for mass-consumer devices

New approach to design active kinematic pairs, transforming resonant non-harmonic periodical vibrations into continuous motion is presented. The specifics of a piezoelectric motor utilizing this approach is that it can be made with limited size of arbitrary cross-section. Some examples of this type of piezomotor are presented, allowing creating miniature in-plane positioning systems and angular scanning systems. Examples of multi-degree-of-freedom piezomotors in mass-consumer devices are shown by “smart” toy prototypes made from standard LEGO™ construction blocks and mini figures.     

Fabrication,modelling and use of porous ceramics for ultrasonic transducer applications

Porous ceramics are of interest for ultrasonic transducer applications. Porosity allows to decrease acoustical impedance, thus improving transfer of acoustical energy to water or biological tissues. For underwater applications, the d_hg_h figure of merit can also be improved as compared to dense materials. In the case of high frequency transducers, namely for high resolution medical imaging, thick film technology can be used. The active films are generally porous and this porosity must be controlled. An unpoled porous PZT substrate is also shown to be an interesting solution since it can be used in a screen-printing process and as a backing for the transducer. This paper describes the fabrication process to obtain such materials, presents microstructure analysis as well as functional properties of materials. Modelling is also performed and results are compared to measurements. Finally, transducer issues are addressed through modelling and design of several configurations. The key parameters are identified and their effect on transducer performance is discussed. A comparison with dense materials is performed and results are discussed to highlight in which cases porous piezoceramics can improve transducer performance, and improvements are quantified.     

超声波电机速度特性测试技术研究

电机性能测试的离散数据中包含各种扰，必须对测试数据进行数字处理。文中用计算编程采集光电编码器脉冲值，并采用曲线拟合、数字滤波的方法对所测信号进行处理，得出电机运行特性曲线，为进一步改进超声波电机运行特性和提高控制的性能奠定基础。     

The design and characteristics of ring type linear ultrasonic motor for X-Y stage

In this paper, the linear ultrasonic motor is newly designed to apply for the actuator of X-Y stage, its vibration mode is analyzed by FEM software, and its characteristics are studied as a function of the inner diameter of the elastic body. As a result from FEM analysis, the stator simultaneously vibrates to radial and bending vibration mode. Based on the result, ring-type linear ultrasonic motors are fabricated according to its inner diameter and its resonant frequency is measured by impedance analyzer. As inner diameter increases, its resonant frequency and velocity decreases. When its inner diameter, input voltage and driving frequency are 10 mm, 20 Vpp and 68.6 kHz, the velocity of the moving body is about 100 mm/s.     

一种用于高压电气设备局放超声检测的新型EFPI传感器

本文介绍了一种新型结构的光纤EFPI超声传感器，可内置于变压器、GIS等高压电气设备，并用新型结构的光纤EFPI超声传感器在不同温度和不同压强条件下，进行局部放电超声信号的检测。新型传感器采用全石英焊接工艺，在F-P腔上开孔，使绝缘介质进入F-P腔，平衡了石英膜片两侧由于温度和绝缘介质产生的压强差，并在石英膜片内表面上局部镀铝膜，提高膜片内表面的光反射率，提升了传感器的灵敏度。通过用传感器在不同温度、不同距离下进行测试，验证了传感器的温度、频率等性能，为检测高压电气设备内部局部放电提供了一种新的检测方法。     

Properties of Cu,Ni, and V doped-LaCrO <Subscript>3</Subscript> interconnect materials prepared by pechini,ultrasonic spray pyrolysis and glycine nitrate processes for SOFC

The ceramic interconnect,La_0.8Sr_0.05Ca_0.15(Cr_{1 −x} , B_x)O₃ (B = Cu, Ni, V, x = 0.02, 0.1, 0.5) (LSCCB) powders were prepared by Pechini method, Ultrasonic Spray Pyrolysis (USP) and Glycine Nitrate Process (GNP). Nano sized powders were synthesized by GNP and their chemical compositions were confirmed by ICP analysis. The electrical conductivities of LSCCCu, LSCCNi, and LSCCV samples were 34 S/cm, 48 S/cm, and 22 S/cm at 800^∘C in air, respectively. Among the LSCCB powders, the LSCCNi sample shows highest relative density and electrical conductivity. In a low oxygen partial pressure, however, LSCCV sample was more stable. The perovskite phase of the composition LSCCV sample is of large practical interest for interconnects in SOFC because of the stability in low oxygen partial pressure.     

基于脉冲反射法的耐张线夹压接质量超声检测技术研究

目前,现有输电线路耐张线夹压接质量的检测过程较为复杂,缺乏有效便捷的检测手段。因此,为了消除新型铝合金芯铝导线在金具压接现场制作中的监管盲区,文章提出了一种基于脉冲反射法的铝合金芯铝导线耐张线夹压接质量超声检测方法,通过对不同导线与钢锚间隙长度的耐张线夹进行超声检测、抗拉试验,研究脉冲在导线压接区与未压接区的反射特性,并给出超声现场检测方案。研究结果表明,基于脉冲反射法的超声检测技术对于导线压接质量的检测和导线压接深度的测量具有一定的有效性和准确性,可以及时发现耐张线夹压接质量不合格导致的断线隐患,提高输电线路运行可靠性。     

Neural approach for temperature‐dependent modeling of GaN HEMTs

Gallium nitride high electron‐mobility transistors have gained much interest for high‐power and high‐temperature applications at high frequencies. Therefore, there is a need to have the dependence on the temperature included in their models. To meet this challenge, the present study presents a neural approach for extracting a multi‐bias model of a gallium nitride high electron‐mobility transistors including the dependence on the ambient temperature. Accuracy of the developed model is verified by comparing modeling results with measurements. Copyright © 2014 John Wiley & Sons, Ltd.     

微机主变保护应用中的几个问题

从工程实际出发，分析了微机主变保护在应用中的几个问题，提出了相应的解决办法，保证了主设备的安全运行，提高了电网运行的可靠性。     

Fundamental experiments on an air‐cushion‐based force‐sensing device for soft physical human–robot interaction

Physical human–robot interaction (PHRI) is an essential concept for human‐cooperative robots (HCRs). Because the force control for PHRI is based on the contact force between a human and an HCR, it is very important to collect the force data accurately. Furthermore, soft contact during force sensing is also necessary for PHRI for safety and security. As a challenge in force sensing for PHRI using a soft material, we aim to develop in this study a novel force‐sensing device based on an air cushion. First, the physical model of the air cushion is represented by an air cylinder with a piston, which is subject to constraint by nonlinear elasticity. Second, the elastic properties of the air cushion are examined under the assumption that it can be formulated as a function of pneumatic pressure and the contact area with a human. The force applied to the air cushion is estimated on the basis of the physical model and compared to the actual force data in the fundamental experiments. Force is successfully estimated using the proposed physical model, and the advantages of the air‐cushion‐based force‐sensing device (ACFSD) are verified through these fundamental experiments. © 2013 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

空间飞行器用锂离子蓄电池储能电源的研究进展

锂离子蓄电池由于具有高的比能量、低的热效应、无记忆效应等突出优点,将成为继镉镍蓄电池、氢镍蓄电池之后的第三代卫星用储能电源,国外已经开始在空间飞行器上应用锂离子蓄电池作为储能电源。介绍了新型锂离子蓄电池储能电源的反应机理、电池的研究进展及锂离子蓄电池在空间电源的应用情况。     

调控云平台IaaS层技术架构设计和关键技术

调控云是中国国家电网有限公司"三朵云"规划中的一个重要组成部分,针对调控云统一和分布相结合的分级部署设计特点,结合国家电力调控中心-区域电网调控中心主导节点和各省级协同节点的两级部署体系构架,以云计算理念为基础,面向电网调控业务设计了调控云基础设施即服务(IaaS)层基本构架,实现了调控云平台硬件资源的虚拟化(共享与动态调配)、数据的标准化和应用的服务化.另一方面,服务器和存储资源的虚拟化、域名系统、负载均衡、读写分离等技术已被引入IaaS层构架中,为调控云各节点均采用双站点模式提供基础支撑,实现了调控云各节点在业务层面均可同时对外提供服务和异地应用双活.