2R柔性机械臂压电抑振的模糊控制实验研究

柔性机械臂在运动过程中不可避免产生弹性振动,对柔性机械臂的振动抑制成为重要研究课题.基于压电陶瓷的模糊控制抑振,利用电阻应变传感器检测机械臂振动信息,经动态应变仪采集到计算机系统,根据控制规律进行模糊运算,得到控制电压;再以该电压驱动压电陶瓷片,产生与振动方向相反控制力矩,抑制机械臂柔性变形.实验结果显示,压电抑振效果显著,模糊控制的鲁棒性较高.     

基于压电陶瓷神经网络模型的模型抑振研究

为达到在脉动气流激励下抑制风洞模型振动的目的,该文提出了基于压电陶瓷作动器神经网络模型的风洞模型主动振动控制方法,并进行了实验研究。首先,分析了风洞模型系统振动特性,建立了内嵌式压电陶瓷作动器的主动振动控制系统,通过模型质心加速度推算出压电陶瓷作动器期望输出抑振力。然后,建立了压电陶瓷作动器期望输出抑振力 激励电压的神经网络模型,并根据该模型设计了一种实时解算加速度为激励电压的控制方法。最后,通过地面试验对控制方法的有效性进行验证。实验结果表明,该控制方法具有良好的实时性和鲁棒性,在锤击试验中,振动加速度衰减时间相比于压电方程线性控制时减小了54.46%,系统阻尼比增大了1.58倍,取得了良好的控制效果。     

超精密机床的压电作动器隔振系统研究

压电作动器是振动主动控制中最常用的一种执行机构。文章分析了各种压电作动器的特点及应用范围 ,并用压电陶瓷作动器对超精密机床实施振动主动控制。结果表明 ,该系统应用控制器克服了压电元件的迟滞特性、蠕变特性和非线性后 ,能有效的控制地基振动对超精密机床的影响 ,提高了超精密机床的加工精度     

压电陶瓷驱动器在机器人柔性臂应用中的研究

研究了片状压电陶瓷驱动器在柔性手臂中的应用,推导了基本压电陶瓷驱动器的柔性臂静力学方程,建立了描述驱动器迟滞特性的Ｐｒｅｉｓａｃｈ模型,提出了一种基于Ｐｒｅｉｓａｃｈ前钏环的ＰＩＤ掏方法对柔性夺动主动控制和轨迹控制俞中以有效地克服片状压电陶瓷驱动器的迟滞特性,消除柔性臂运动产生的振动,实现柔性臂的精度轨迹控制。     

一种新型自感知作动器及其应用

利用压电片的正逆压电效应。提出了一种基于分时结构的自感知作动器，将压电片作为传感器和作动器的功能在时间上进行分离，以实现用同一压电片在作动与传感之间的功能切换，并探讨了其用于主动控制的可行性。对一悬臂梁的振动主动控制研究表明该自感知作动器在实际上是可行的。     

超声乳化联合人工晶体植入术治疗外伤性白内障

针对传统压电致动器具有制造困难、易碎、效率低等缺点,该文结合压电智能材料发展的最新趋势,使用由美国航空航天局兰利研究中心(LaRC)研发的新型压电智能材料--条状压电复合纤维(MFC)作为致动器,以柔性悬臂梁为控制对象,研究了振动主动控制问题.结合LaRC-MFC致动器的研究现状,该文以实验测量所设定的驱动电压对应的压电智能梁的位移数据作为基础,通过数值插值算法分析了致动器与悬臂梁的耦合关系;并采用正位反馈控制(PPF)策略对这种新型的控制结构进行了试验研究.实验结果表明,条状压电复合纤维具有良好的致动效能;采用提出的振动主动控制结构,抑振效果明显.     

振动控制中压电元件优化配置研究进展

压电材料以其工作频率宽,响应快,性能稳定和力电耦合效应强等优点已被广泛应用到结构振动主动控制中,该文对压电元件在结构振动主动控制中的优化配置问题进行综述。根据力电耦合关系,给出振动控制中压电元件的传感和作动方程,并推导了压电传感器/作动器的优化配置问题的数学模型;对优化配置问题中基于控制系统性能和系统能量的优化配置准则的研究状况进行总结和评述;同时对优化配置计算中常用方法进行了概括和分析,文中分别对压电传感器/作动器的位置、数目、尺寸和控制增益的优化研究成果进行总结,为工程实际提供方便快捷的布置方案,最后给出需要进一步研究的几个问题。     

结构振动控制中压电阻尼技术研究：（二）压电主动阻尼技术

对压电主动阻尼技术进行了理论和实验研究，结果表明，采用压电陶瓷元件（ＰＺＴ－５１）作为控制系统中的传感器与致动器，通过主动阻尼控制键，能有效抑制结构的振动响应．     

压电陶瓷驱动FSM三自由度柔性支撑设计

为了有效吸收反射镜偏转造成驱动点的横向位置偏差,保护压电陶瓷驱动器,抑制反射镜在非工作方向上的自由度,提高系统谐振频率,设计了基于压电陶瓷驱动的快速反射镜三自由度柔性支撑。首先根据压电陶瓷驱动的快速反射镜对柔性支撑的设计要求确定了由支撑杆与支撑片组成的三自由度四周式柔性支撑方案,再利用压杆稳定性理论与变形能法对支撑杆与支撑片进行参数设计,最后利用workbench对设计结果进行分析。有限元分析结果表明,直径1 mm、长度8 mm的柔性支撑杆的应用可以使压电陶瓷的剪切位移减少86.7%,柔性支撑片的应用使反射镜一阶模态为轴向平移振动,谐振频率为360 Hz,二三阶模态为反射镜两轴偏摆振动,谐振频率为420 Hz,而高阶模态在1 000 Hz以上。三自由度柔性支撑可以有效防止压电陶瓷受到剪切破坏,提高快速反射镜结构谐振频率,有利于提高系统闭环带宽。     

基于压电驱动的纳米级精密定位系统的研究

利用压电陶瓷致动器作为驱动元件设计了X-Y两自由度精密定位工作台,并利用有限元分析法对机构进行了优化设计,采用电阻应变片作为微位移检测传感器,在此基础上设计了闭环控制器,该控制器包括压电陶瓷驱动单元、微位移传感器检测单元和中央处理单元,最后利用PID控制法进行了闭环控制实验研究。实验结果表明,本系统具有较好的控制品质和优异的动态性能,在对10μm×10μm两自由度工作台的控制中,闭环控制精度达10nm,阶跃响应的稳定时间小于8ms。     

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.     

A rigorous proof of MIMO channel capacity’s increase with antenna number

It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output（MIMO） communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.     

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