超声电机温升、结构参数和输出特性的相互关系

通过超声电机温度特性实验,分析超声电机产生热量的途径;研究预压力和摩擦层厚度对超声电机温升、运行转速和堵转力矩的影响规律;提出估计温升、转速和堵转力矩关系的经验公式。研究有助于控制温升,改善电机运行特性。     

新型锥壳形旋转超声电机的研究

该文提出了一种新型锥壳形旋转行波超声电机,该锥壳形超声电机振子的三阶弯曲振动模态可以将面内、外弯曲振动结合起来,实现新型振动模式的行波驱动。利用有限元软件确定了振子结构尺寸、三阶弯曲振型及频率并制作了原理样机,对原理样机振动特性及输出性能进行了测试。测试结果表明,当激励电压峰峰值为240 V,谐振频率为27.53 kHz时,空载时超声电机最高转速为85.8 r/min,堵转力矩为441 mN·mm。     

一种控制力矩陀螺用双频驱动的超声电机

控制力矩陀螺的框架电机要求控制精度高,机械响应快,转速低,质量小,能适应高真空、高温差的工作环境。为满足上述需求,该文为控制力矩陀螺设计了一种异型模态超声电机,用以驱动力矩陀螺框架。并基于有限单元法计算及优化了样机外形尺寸,完成电机速度特性和负载特性的测试及优化。结果表明,该超声电机由超声电机定子、力矩陀螺转轴、基座组成。定子通过铰链固定于基座,弹簧机构对其施加预压力。超声电机质量25 g,最大输出扭矩0.04 N·m,满足控制力矩陀螺的使用要求。     

一种圆筒型转子的中空型超声电机的研制

针对某些飞行器舵机控制系统需要旋转型超声电机具有中空结构、转子与负载结构融合以及具备一定的保持力矩等特定工程技术需求,该文提出了一种圆筒型转子与舵翼结构一体设计(外圈输出)的中空型超声电机,开展了该型电机的结构及预压力施加方案的设计和试验研究。建立了电机定子的有限元模型,分析了不同结构尺寸对定子模态的影响,进行了结构尺寸的灵敏度分析,优化了定子的结构,计算出其共振频率、振动幅值。最后试制出了原理样机。实验表明,在激励电压为450 V,激励频率为40.2 kHz时,样机的空载转速可达208 r/min,堵转力矩可达0.35 N·m。     

旋转行波超声电机最优预压力的研究

为提升旋转行波超声电机输出性能,研究其在不同负载下的最优预压力,针对TRUM-70H超声电机进行了理论计算和实验验证。建立超声电机动力学模型,分析了预压力对超声电机机械特性的影响;以TRUM-70H超声电机为对象,分析其最优预压力与负载力矩间的关系;搭建超声电机多功能测试平台,验证理论推导结果,并指出误差存在的原因;根据研究结论,提出超声电机装配时应根据负载选用预压力。结果表明,预压力和负载力矩对超声电机转速的影响存在耦合关系;在超声电机有效工作范围内,最优预压力值与负载力矩近似呈线性正相关;装配时根据实际负载需求设定超声电机预压力,可提高其输出效率。     

一种基于ARM处理器的电机力矩测试技术研究

电机输出扭矩、转速和输出效率是电机测试中最重要参数,测量精度直接影响到电机整体控制性能和运行效率。本文开发了一套基于ARM处理器的电机力矩测试设备,采用磁滞制动器作为负载电机,通过ARM微处理器使负载电机运行于空载模式、负载跟随模式、扭矩模式和速度模式,测试曲线可编程。本文计的电机测试设备具备测量周期短、精度高、可靠性高、灵活编程、性能稳定的特性,可广泛应用于中小功率电机伺服控制测试系统。     

PPTC在冷却风扇调速电阻上的应用

正在很多电机的设计中,都会使用PPTC来实现电机的过温、过流和堵转保护。但是由于PPTC器件所能承受的持续恒定的工作电流值限制,因此在有些大功率的汽车电机保护中一直无法应用。其中汽车前引擎箱中的冷却风扇的电机保护就是个典型,但是如果设计者能转换一下思路,其实PPTC依然能用于电机的过流和堵转保护中,这里我们就拿汽车冷却风扇的电机堵转保护来做一个解说。     

小容量具有反馈控制的电机速度控制器

无论是什么类型的电动机，其转速和力矩都存在着一定关系。普通电机当转矩增加时转速就减小，而某些生产工艺要求驱动电机在速度变化时，转矩变化不大。这就需要对电机引入适当的控制（例如反馈控制）。为此下面介绍一种实用的电机速度控制器。电路的组成和工作过程电路如...     

盒式收录机电机速度控制电路

盒式收录机驱动电机均采用电子稳速方式.其电路原理可归纳为一个负反馈的自调整系统;在电路构成上有分立元件和集成电路两种形式.用分立元件组成的电子稳速电路如图1所示.图中电机DJ在一定的转速下可以等效为一个内阻R_DJ和一个电动势E_DJ;E_DJ同电机转速成正比.当电机负载力矩增大时,电机转速下降,电机反向电动势减小,相当于电机内阻变小,使图1中的B点电位上     

一种电能表码轮驱动步进电机堵转检测芯片设计

电能表码轮驱动步进电机的堵转将漏掉用电计数。为了检测电能表码轮驱动步进电机堵转的状态,设计了专用检测芯片。芯片基于对步进电机检测线圈的脉冲信号宽度的分析,采用模数混合集成电路检测出堵转脉冲数。其中模拟电路主要是比较器,对检测线圈的信号进行数字化变换。这种检测原理对检测系统的时钟误差有较大的容忍度,可达-23%,＋45%...     

Resolution Enhancement Technology:Integrated Process Solutions using OPC

DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.     

Cost-effective test solutions for smart card and other integrated flash applications

From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.     

Theoretical analysis of the relationship between the Brillouin gain coefficient and the strain in the optical-fiber sensors

The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.     

An improved parallel thinning algorithm with two subiterations

The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.     

Novel fiber-optical interferometer with miniaturized probe for in-hole measurements

Today, micro-system technology and the development of new MEMS （Micro-Electro-Mechanical Systems） are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.     

Study of waveguide coupling efficiency in hybrid silicon lasers

This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel＇s.     

Teleportation of an arbitrary unknown N-qubit entangled state under the controlling of M controllers

A new quantum protocol to teleport an arbitrary unknown N-qubit entangled state from a sender to a fixed receiver under M controllers(M < N) is proposed. The quantum resources required are M non-maximally entangled Greenberger-Home-Zeilinger (GHZ) state and N-M non-maximally entangled Einstein-Podolsky-Rosen (EPR) pairs. The sender performs N generalized Bell-state measurements on the 2N particles. Controllers take M single-particle measurement along x-axis, and the receiver needs to introduce one auxiliary two-level particle to extract quantum information probabilistically with the fidelity unit if controllers cooperate with it.     

Diode-end-pumped Nd:YVO4/LBO lasers with 4.2W continuous-wave output at 457 nm

A continuous-wave (CW) 457 nm blue laser operating at the power of 4.2 W is demonstrated by using a fiber coupled laser diode module pumped Nd: YVO4 and using LBO as the intra-cavity SHG crystal With the optimization of laser cavity and crystal parameters, the laser operates at a very high efficiency. When the pumping power is about 31 W, the output at 457nm reaches 4.2 W, and the optical to optical conversion efficiency is about 13.5% accordingly. The stability of the out putpower is better than 1.2% for 8 h continuously working.     

Call for Papers

正Wireless Body-area Networks The last decade has witnessed the convergence of three giant worlds:electronics,computer science and telecommunications.The next decade should follow this convergence in most of our activities with the generalization of sensor networks.In particular with the progress in medicine,people live longer and the aging of population will push the development of wireless personal networks     

Call for Papers—Feature Topic,Vol.12,No.7,2015

正Information Centric Networking Information-Centric Networking(ICN) is an emerging direction in Future Internet architecture research,gaining significant tractions among academia and industry.Aiming to replace the conventional host-to-host communication model by a data-centric model,ICN treats data content as the first