高超声速飞行器超螺旋滑模自适应控制

针对具有强耦合性、严重非线性等特性的高超声速飞行器控制问题,提出了一种改进的自适应二阶滑模控制方法。首先,在高超声速飞行器纵向模型中加入不确定因素,建立了具有参数不确定性、模型不确定性以及干扰的控制模型;其次,在所建立模型的基础上,利用类二次型Lyapunov函数设计了基于super-twisting算法的二阶滑模自适应控制器;最后,仿真结果表明,对具有未知上界不确定性的系统,该方法设计的控制器较普通二阶滑模控制器,有更好的跟踪效果以及鲁棒性。     

基于反步法的四旋翼飞行器自适应滑动模态控制

针对四旋翼飞行器非线性模型系统参数不确定性和外界干扰随机性的控制问题,提出一种基于反步法的自适应滑模控制器设计方法。将四旋翼飞行器动力学模型进行简化分解为欠驱动和全驱动两个部分;对相应的不确定性进行估计,选取适当的Lyapunov函数,采用反步的方法回馈递推得到自适应滑模控制律,从而提高飞行器对外界环境变化自适应能力。依据该方法在Matlab/Simulink环境下进行控制器设计并完成仿真验证。结果表明,基于反步法的四旋翼飞行器自适应滑动模态控制方法比非自适应控制方法具有更好的适应性和鲁棒性。     

一种基于神经网络的自适应非线性自动舵

针对仅航向角可测量的船舶航向控制系统,提出一种基于神经网络的自适应非线性航向控制器.首先采用神经网络在线逼近系统中的未知项,并设计滑模观测器在线估计艏摇角速度;然后基于动态面控制思想设计非线性观测器-控制器.利用Lyapunov方法证明了误差变量是一致最终有界的.以某自航船模为例仿真,结果表明所提方法鲁棒性好,且操舵合理.     

共轴八旋翼无人机神经自适应滑模控制设计

针对共轴八旋翼无人机位置与姿态的跟踪控制问题,在充分考虑模型不确定性及外部干扰的情况下,提出一种神经自适应滑模控制方法.首先,将共轴八旋翼无人机动力学系统分为两个子系统,即全驱动子系统和欠驱动子系统.然后,运用神经网络对模型参数不确定部分和外界干扰项进行估计,设计一种合适的滑模控制器,根据所设计的控制器和Lyapuno...     

改进型BP神经网络的非线性多模型自适应控制

针对一类参数未知的非线性离散系统,提出一种基于改进型BP神经网络的多模型控制方法.首先将非线性系统表示为线性部分和非线性部分.当非线性部分对系统影响较小时,则直接采用基于固定模型和自适应模型而设计的鲁棒控制器对系统进行控制;而当非线性部分对系统影响较大时,则采用基于改进的BP神经网络的自适应控制.其次,利用切换准则对控制输入进行平滑切换并给出了稳定性证明.最后,仿真结果表明所提方法能提高系统控制品质、减少控制信号的振荡.     

基于滑模扩张干扰观测器的固定翼无人机动态逆控制

为解决存在模型不确定性与外部干扰时的固定翼无人机控制问题,设计了一种非线性滑模扩张干扰观测器与快速响应动态逆相结合的控制律。在扩张干扰观测器设计的基础上,引入滑模原理设计了一种非线性滑模扩张干扰观测器,对干扰及其变化率进行实时估计;将无人机姿态运动方程分为姿态角慢回路与姿态角速率快回路,依此分别设计动态逆控制律,并基于干扰估计量对未知扰动进行补偿,同时在快回路控制器中加入由快速跟踪微分器(TD)估计的指令值微分量,以提高控制器的响应速度,最后证明了复合控制器的稳定性。仿真实验表明,设计的复合控制器能够对无人机姿态运动进行高效控制。     

航空发动机模糊滑模变结构控制研究

针对航空发动机是一个具有时变不确定性的非线性系统,结合模糊控制和滑模变结构控制的特点,提出了一种基于模糊滑模变结构控制的航空发动机控制方法.采用线性滑模面和指数趋近律设计变结构控制器,应用模糊逻辑系统自适应调节切换增益,避免了传统滑模变结构控制系统在到达阶段对不确定性的敏感性,消除了滑模控制中的抖振.通过数字仿真,结果表明所设计的模糊滑模变结构控制器对系统的参数摄动和外部干扰具有不变性,使被控系统在整个控制阶段都具有较强的鲁棒性.     

具有外部扰动的非线性多智能体系统的自适应控制分析

阐述在未知扰动下含有未知量的非线性多智能体系统控制问题。提出了一种分布式设计,可实现在加权有向图拓扑下的多智能体系统一致性跟踪控制。每个智能体由有未知量的严格反馈非线性系统建模,并包含外部干扰。通过backstepping技术和神经网络的方法,在只需要自己和相邻智能体之间的相对状态信息的情况下,为每个从智能体构造自适应分布式控制器。设计的控制器和自适应控制率可保证领航者与所有跟随器之间的跟踪误差收敛到原点的一个小邻域。运用Radial Basis Function(RBF)神经网络用于逼近未知的非线性函数,并设计了一个非线性扰动观测器用于估计未知的外部扰动。采用Nussbaum函数来处理模型中未知符号的参数,仿真结果验证了所提方法的有效性。     

四旋翼飞行器双环条件积分滑模控制

针对存在阵风干扰及未建模特性下的四旋翼飞行器轨迹跟踪控制,基于非线性滑模控制技术,结合条件积分思想及Lyapunov稳定性理论设计了一种位姿双环条件积分滑模控制器.在获得四旋翼非线性动力学模型后对其进行线性化,简化被控对象数学模型,提高控制器设计效率.利用条件积分滑模控制律设计了位置环和姿态环的轨迹跟踪控制器,实现了控...     

小扰动机器人纵向非线性控制电路系统设计

传统的小扰动机器人纵向非线性控制方法采用传感器通过敏感元件实现驱动器和执行系统联动控制,但控制系统容易出现非线性随机干扰失真。提出基于自校正模型参考自适应的小扰动机器人纵向非线性控制方法,利用改进后的控制算法进行电路系统设计。当小扰动机器人纵向非线性控制系统受到随机干扰作用时,根据自适应多通道加权控制律,机器人非线性控制系统的测量误差按指标随时调整控制器参数权重,给出合适的控制信号,在机器人的执行控制系统中设置一个初始权值,参考模型并联于被控系统,在伺服控制中采用最小方差法确定控制规律,实现机器人的纵向非线性控制,最后进行PCB电路板的设计。实验和调试结果表明,采用该系统能有效实现对机器人的非线性控制,控制品质和精度较高,收敛性和稳定性较好。     

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