四旋翼飞行器建模与PID控制器设计

为了实现对四旋翼飞行器的稳定飞行控制,对四旋翼飞行器建立了动力学数学模型,并采用准LPV法将非线性模型线性化,在建立的动力学模型基础上,对飞行器垂直速率、俯仰速率、横滚速率、偏航速率四个独立通道上分别设计了PID控制器.并通过Matlab/Simulink软件进行控制系统仿真,并对仿真结果进行分析,仿真结果验证了PID算法的有效性.     

基于动态调节的小型四旋翼飞行器的控制系统

通过对四旋翼飞行器进行动力学建模,设计了简单PID控制器和动态调节PID控制器,并对动态调节PID进行了模糊规则的建立,成功地实现了对四旋翼姿态的控制;通过系统仿真比较了两种PID控制器的控制效果,结果表明,动态调节PID控制器相比于简单PID控制器具有更好的控制效果。     

量化因子自整定的四旋翼飞行器模糊PID控制

针对四旋翼飞行器的非线性飞行控制模型,提出了一种新改进的量化因子自整定二维直接控制量型模糊PID控制器。通过分析量化因子与模糊控制器输入输出的模糊逻辑关系,对量化因子分别设计模糊整定器并确定了相应的模糊输入量以及模糊规则表,然后利用自整定算法实现量化因子在线实时调整。通过对四旋翼飞行器进行动力学建模以及控制通道分析,进行了姿态飞行控制仿真实验。与传统PID型模糊控制器相比,本文设计的控制器在动态响应速度及抗外界干扰性能方面效果更优。     

基于串级PID的多旋翼精确定点悬停控制研究

针对多旋翼飞行器的精准定点及稳定悬停控制问题,采用串级PID控制算法设计位姿控制器对多旋翼的位置和姿态进行控制.对多旋翼进行运动学及动力学分析,建立数学模型,并对所建模型进行分析再建立控制分配模型.为了简化控制器设计,将控制器分为位姿控制器和控制分配器两部分进行设计,改变控制分配器可以实现对不同旋翼的飞行控制,具有更广的适用性.仿真结果表明,多旋翼无人机具有较快的响应速度,垂直起飞和平飞两个阶段衔接紧密,能够准确到达给定目标位置并进行稳定悬停.     

三旋翼构型倾转旋翼无人机建模与悬停控制研究

针对一种三旋翼构型倾转旋翼无人机的建模和悬停控制问题进行研究,采用牛顿欧拉法建立了这种三旋翼构型倾转旋翼无人机的六自由度非线性动力学模型,并对模型进行简化。在此基础上,分别设计了悬停模式下的高度控制器和姿态控制器。高度控制器是在反馈线性化的基础上采用PID控制设计而成,姿态控制器由基于Backstepping的PID控制器构成。最后,对所设计的控制器进行仿真实验,实验结果表明:所设计的控制器能满足系统的控制性能要求。     

四旋翼无人机建模及其PID控制律设计

文中对四旋翼无人机进行建模与控制。在建模时采用机理建模和实验测试相结合的方法,尤其是对电机和螺旋桨进行了详细的建模。首先对所建的模型应用PID进行了姿态角的控制。在此基础上又对各个方向上的速度进行了PID控制。然后在四旋翼飞机重心进行偏移的情况下进行PID控制,仿真结果表明PID控制律能有效的控制四旋翼无人机在重心偏移情况下的姿态角和速度。最后为了方便控制加入了控制逻辑     

四旋翼无人机轨迹跟踪控制系统设计

针对四旋翼无人机参数不确定性和对外部干扰敏感的问题,提出一种基于线性自抗扰的轨迹跟踪控制系统设计方案。线性自抗扰能够很好地克服无人机的强耦合性、模型不确定性以及外部干扰问题。将四旋翼无人机的轨迹跟踪控制系统分为内外两个环路,内环采用线性自抗扰控制器,外环采用简单的PD控制器。在仿真平台上对线性自抗扰控制系统进行轨迹跟踪实验,并与传统的PID控制系统进行对比分析。通过仿真实验证明,所设计的线性自抗扰控制器不仅能够很好地估计并补偿系统所受内外部干扰,而且对四旋翼无人机参数的不确定性具有较强的鲁棒性,能够满足无人机姿态调节快速和高稳定度的控制要求,性能指标明显优于PID控制器。     

四旋翼飞行器姿态与位置的DIC-PID控制

针对四旋翼飞行器姿态与位置的解耦控制,提出了一种动态逆控制与PID结合的混合控制策略。首先,将四旋翼当作单刚体,通过牛顿-欧拉方程获得其非线性动力学模型。其次,用动态逆控制设计内回路控制器,用PID控制设计外回路控制器,实现姿态与位置通道的解耦控制。最后,在仿真环境下,通过阶跃响应和跟踪上升螺旋线检验了所提控制算法的稳定性与有效性。同时,将控制算法写入飞行控制器,通过飞行实验验证了所提控制算法的实用性。结果表明,所提控制算法对外界扰动与未建模动态有较好的抑制能力,能够满足四旋翼飞行器姿态控制与位置控制的需求。     

三旋翼飞行器建模及自抗扰控制

根据国内外旋翼飞行器研究现状,研究了一种尾桨可倾斜的三旋翼飞行器.首先介绍其机械结构,对机体受力情况和整体力矩进行分析,使用牛顿-欧拉法建立了飞行器的数学模型;然后针对系统高度非线性、强耦合、易受干扰的特点,采用自抗扰控制器对系统进行控制;最后在Matlab/Simulink平台上对系统进行飞行控制仿真以及抗扰性测试,并与PID控制器进行对比分析.仿真结果表明,相较于PID控制器,自抗扰控制器能更加快速、稳定地实现姿态及高度调节,同时还具有更强的抗干扰能力.     

Integral Backstepping法在四旋翼飞行器抗干扰研究中的应用

针对四旋翼飞行器多输入多输出、强耦合、非线性且欠驱动等特点带来的对外部干扰敏感问题,提出了基于积分型反步法的控制系统。首先建立了四旋翼飞行器的动力学模型,然后设计了位置控制回路外环及姿态控制回路内环的双闭环控制结构PID控制器,和由李雅普诺夫稳定性理论证明的Integral Backstepping法的控制器,最后在Matlab/Simulink中对这两种控制器进行仿真实验分析。结果表明,使用Integral Backstepping算法的控制器模型在控制精度、调节时间和抗干扰性上都明显优于经典PID算法。     

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.     

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.     

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