压电微动平台的改进PID控制

为使压电微动平台具有良好的静动态特性,即响应快,超调量小,无振荡及稳态误差小,采用比例、积分、微分(PID)控制法来对其进行定位控制。将常规PID控制中积分环节的矩形积分改进为梯形积分,以提高压电微动平台的控制精度;采用微分分离法对常规PID控制中的微分环节进行改进,以使压电微动平台在具有良好稳定性的情况下,具有很快的响应速度。实验验证了压电微动平台改进PID控制的有效性,结果表明,压电微动平台对4μm阶跃参考位移的响应时间为0.05s,输出略有超调,但无振荡,且稳态误差几乎为0;在变幅值三角波及任意波形参考输入作用下,压电微动平台的输出可很好地跟踪输入。     

采用变间隔阈值PI模型的压电平台前馈控制

为提高压电微动平台在运动过程中的定位精度,设计前馈控制器来控制平台输出位移。首先,根据压电微动平台迟滞曲线的特点,在不降低模型精度要求的前提下,对迟滞曲线非线性较大区域进行细密划分,对线性较好区域进行稀疏划分,进而建立了变间隔阈值的平台Prandtl-Ishilinskii(PI)迟滞模型;接着,通过对所建平台迟滞模型求逆,给出了平台的前馈控制算法;最后,将所设计的前馈控制器作用于平台,对其进行了实际控制。结果表明,在4μm的目标阶跃激励下,平台的响应时间为0.01s,无超调,稳态误差中线从无控制时的0.4~0.5μm减小为0~0.2μm;在最大值为20.7μm的幅值衰减三角波输入作用下,平台定位误差中线的最大正负差值从无控制时的3.82μm减小到1.15μm。所设计的控制器可有效减小压电微动平台的迟滞误差。     

基于液压放大的压电微动平台设计与试验

针对传统微动平台难以满足微/纳米定位的要求,该文结合液压放大原理,提出一种基于液压放大的两自由度压电微动平台,并对其进行了结构设计。采用正交设计方法对其进行有限元双向流固耦合分析,优化了其结构参数。研制了实物样机并进行试验研究。开环控制试验结果表明,当压电驱动器输入为90 μm时,压电微动平台最大输出位移为603.0 μm,放大倍数约为6.7;闭环控制试验结果表明,采用分段微分、积分、比例(PID)算法能降低超调量,且响应时间、稳态时间均减小,稳态误差降低（为±0.2 μm）,实现了微动平台的大范围输出精密定位。     

小型红外成像制导稳定平台控制算法研究

针对小型稳定平台转动惯量小易受冲击力矩扰动影响制导精度的问题,先对稳定平台的力矩刚度进行分析,根据分析结果对传感器与执行机构进行选型。然后利用经典控制理论为速率闭环设计了普通PID控制器。通过分析普通PID控制的不足,对其进行抗饱和积分、适时不完全微分与非线性优化,在此基础上引入对误差变化率的观测量,针对大冲击力矩扰动设计了专家PID控制器。最后利用dSPACE搭建的半实物仿真平台对算法进行仿真测试,测试结果表明专家PID控制减小了冲击扰动造成的角速率误差与角位置误差,使稳定平台具有更好的动态力矩刚度。     

压电微动平台的极点配置PID控制

为提高压电微动平台的位移输出精度,设计极点配置比例、积分、微分(PID)控制器对其进行控制。首先,在对压电执行器进行电学特性、机电特性分析的基础上,建立了压电执行器的数学模型;其次,在对平台进行受力分析、运动分析的基础上,建立了平台的动力学模型;然后,在保持平台极点虚部不变,且将系统闭环阻尼比取为1的情况下,将平台极点沿着平行于实轴的方向平移,设计出平台的PID反馈控制器;最后,实验验证了所设计控制器的有效性。实验结果表明,所设计的控制器可使平台具有较快的响应,在不考虑传感器噪声水平的情况下,平台在控制系统作用下的定位误差基本为0。     

多层压电执行器输出位移的模糊神经元PID控制

为了提升压电执行器输出位移的性能,该文采用模糊神经元比例、积分、微分(PID)控制器对其输出位移进行控制。首先,分析了压电悬臂梁执行器机电特性,搭建其动力学模型;其次,将模糊算法、神经元、PID三者相结合,设计出一种能快速、精确、抗干扰能力强的控制器;最后,对压电悬臂梁执行器控制系统进行了仿真,并通过实验验证了该控制器的性能。结果表明,压电执行器对5 μm阶跃目标位移的响应时间为0.3 s,且无超调,稳态误差中线由无控制时的0.57~0.66 μm减小为几乎为0;在跟踪由正弦信号、常值信号、斜坡信号所组成的目标位移时,跟踪误差几乎为0。该文所设计控制器可消除压电执行器的定位误差,并使其具有抗干扰能力强,响应迅速,无超调量等优点。     

空间组网光通信粗跟踪系统的模型预测控制

针对一对多组网光通信粗跟踪伺服控制系统,通过解析法和正弦扫频辨识建立了粗跟踪系统的模型,然后依据数学模型设计了模型预测控制器(MPC),进行了与比例-积分-微分(PID)控制器的对照实验。实验结果表明MPC控制器能以10μrad的误差跟踪0.1 Hz的正弦信号,跟踪精度是PID控制器的两倍。在叠加了50 Hz,幅值1.8 m随机噪声的情况下,MPC控制器的最大稳态跟踪误差为55μrad,只有PID控制器最大稳态跟踪误差的一半。并且在运动平台的粗跟踪实验中,MPC控制器的稳态误差最大为15μrad,PID控制器的稳态误差最大为25μrad。表明MPC控制器可以有效提高一对多光通信粗跟踪控制效果。     

基于PI迟滞模型的压电陶瓷复合控制算法研究

为减小压电陶瓷的迟滞非线性对系统跟踪精度的影响,该文采用经典的存在逆解析的PI迟滞模型对压电陶瓷的迟滞特性进行建模,将PI模型的逆模型用于压电陶瓷的前馈控制算法中,然后设计了神经元比例、积分、微分(PID)反馈控制算法,将前馈控制算法与神经元PID反馈控制算法结合得到了压电陶瓷的复合控制算法。将仅含前馈的控制算法和复合控制算法在压电陶瓷的控制器上执行,实验结果表明,仅含前馈的控制算法的跟踪误差为1.256μm,而复合控制算法的跟踪误差仅为0.092μm,该复合控制算法使跟踪精度提高了1.164μm。     

SECM微纳米定位建模及控制器设计

为适应扫描电化学显微镜（SECM）常规应用中100nm左右的微定位精度需求,同时降低其微定位控制器的成本,在分析SECM压电工作台运动定位数学模型的基础上,结合SECM实际应用中的特点,将压电工作台数学模型进行了合理的简化,并在此基础上设计了算法简单且易于实现的开环微定位控制器。以CHI900B型扫描电化学显微镜的三维压电工作台为实验对象进行建模和控制器设计,实验结果表明,压电工作台运动定位平均跟踪误差和最大跟踪误差分别为0.093、0.115μm,误差约0.1μm,可满足SECM常规应用中的微定位精度需求。建模过程和控制器设计简单易行且无须额外的微定位传感器,适于SECM的常规应用。     

SECM微纳米定位建模及控制器设计

为适应扫描电化学显微镜(SECM)常规应用中100nm左右的微定位精度需求,同时降低其微定位控制器的成本,在分析SECM压电工作台运动定位数学模型的基础上,结合SECM实际应用中的特点,将压电工作台数学模型进行了合理的简化,并在此基础上设计了算法简单且易于实现的开环微定位控制器。以CHI900B型扫描电化学显微镜的三维压电工作台为实验对象进行建模和控制器设计,实验结果表明,压电工作台运动定位平均跟踪误差和最大跟踪误差分别为0.093、0.115μm,误差约0.1μm,可满足SECM常规应用中的微定位精度需求。建模过程和控制器设计简单易行且无须额外的微定位传感器,适于SECM的常规应用。     

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.     

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.     

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.     

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.     

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.     

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