A novel three‐dimensional guidance law implementation using only line‐of‐sight azimuths

A novel three‐dimensional guidance law using only line‐of‐sight azimuths based on input‐to‐state stability and robust nonlinear observer is proposed for interception of maneuvering targets. The proposed guidance law does not need any prior information of unknown bounded target maneuvers and uncertainties. Since in practice the line‐of‐sight rate is difficult for a pursuer to measure accurately, a nonlinear robust observer is introduced to estimate it. A three‐dimensional guidance law with bearing only measurement is obtained for interception of maneuvering targets. The presented algorithm is tested using computer simulations against a maneuvering target. Copyright © 2014 John Wiley & Sons, Ltd.     

Synchronization of Instantaneous Coupled Harmonic Oscillators With Communication and Input Delays

This paper investigates the synchronization issue of instantaneous coupled harmonic oscillators with communication and input delays. A distributed synchronization algorithm is proposed for such oscillator systems, and some general algebraic criteria on exponential convergence are established for the algorithm. The main contributions of the present investigations include: (i) the directed network topology is first considered in the case of instantaneous interaction; (ii) both the time‐varying communication and input delays are simultaneously addressed; (iii) the effects of communication and input delays on synchronization performance of coupled harmonic oscillators are discussed. It is shown the communication delays have a more important impact than the input delays on determining synchronization dynamics of coupled harmonic oscillators. Explicitly, in absence of communication delays, coupled harmonic oscillators can achieve synchronization oscillatory motion, whereas, so long as communication delays are nonzero at infinite multiple impulsive times, its synchronization (or consensus) state is zero. Finally, numerical examples demonstrate the obtained theoretical results.     

基于嵌入式Linux系统的键盘驱动设计

摘要：为了适应嵌入式设备外设的多样性,本文以特殊矩阵键盘为例,设计了一套完整的驱动控制模块。硬件电路设计采用外扩3片SN74HCl64芯片的方式,节省了GPIO引脚的使用,大大提高了利用效率。同时,在此基础上引出了Linux内核中input子系统的特性和工作机制,呈现了较为完整的输入事件由内核空间传递到用户空间进程的过程。实验结果表明,设计的驱动模块具有良好的实时性和准确性。     

On input‐to‐state stability‐based design for leader/follower formation control with measurement delays

This paper addresses the design of low‐level controllers for leader–follower formations of nonholonomic vehicles in the presence of bounded measurement delays. The concept of input‐to‐state stability is extended to encompass the effect of bounded delays and restrictions on the input. A method is proposed to integrate a Smith predictor in a backstepping design on the basis of nested saturations and nonlinear small‐gain assignment, which allows for time delays in the feedback loop. Robustness analysis under uncertain bounded time delays is provided, and design tradeoffs resulting from the use of bounded controls are discussed. Illustrative simulations are shown to validate the design and robustness analysis in the context of a simple leader–follower trailing control problem. Copyright © 2012 John Wiley & Sons, Ltd.     

Small‐signal and noise modeling of class of HEMTs using knowledge‐based artificial neural networks

In this article, the neural network approach is exploited for development of bias‐dependent small‐signal and noise models of a class of microwave field effect transistor (FETs) made in the same technology but differing in the gate width. The prior knowledge neural approach is applied. Introducing gate width at the input of proposed neural networks, as well as the S/noise parameters of a device that belongs to the same class as the modeled device representing the prior knowledge, leads to very accurate scattering and noise parameters' modeling, as exemplified by modeling of class of pseudomorphic high electron mobility transistor (pHEMT) devices. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Fault Detection for Nonlinear Systems with Unknown Input

This paper extends the problem of fault detection for linear discrete‐time systems with unknown input to the nonlinear system. A nonlinear recursive filter is developed where the estimation of the state and the input are interconnected. Unknown input which can be any type of signal was obtained by least‐squares unbiased estimation and the state estimation problem is transformed into a standard unscented Kalman filter (UKF) problem. By testing the mean of the innovation process, a real‐time fault detection approach is proposed. Simulations are provided to demonstrate the effectiveness of the theoretical results.     

基于802.11n的WLAN安全解决方案研究

随着无线局域网技术的飞速发展,IEEE 802.11n是无线局域网技术的最新标准,介绍了基于802.11n的MIMO(多入多出)、OFDM(正交频分复用)和双频带等无线通信系统的关键技术,分析了在802.11n标准下WLAN的安全问题,通过数据加密、双向认证、动态WEP密钥和虚拟专用网络等方法,提出了基于802.11n的WLAN安全解决方案。     

基于Matlab的计算机辅助电路分析

结合若干经典电路的分析实例,如二阶欠阻尼电路的零输入响应、频率响应及二端口电路阻抗匹配的计算等,针对烦琐的计算和公式推导,提出了Matlab编程的方法加以解决,并给出了具体的Matlab电路分析程序。将Matlab软件作为电路分析工具,通过计算机仿真实验来分析和解决电路问题,方便直观,运算效率更高,值得推广。     

具有时变输入时滞的不确定T-S模糊系统的鲁棒稳定性

本文主要针对不确定的输入变时滞 T-S 模糊系统设计模糊控制器使系统鲁棒稳定. 首先基于 Lyapunov-Krasovskii 泛函方法, 通过引入更多的松弛变量矩阵, 以 LMI 形式给出使此模糊系统稳定的充分条件. 在设计模糊控制器时并不要求满足时变输入时滞的导数小于1的限制条件. 最后给出数值仿真例证本文提出的结果的有效性且保守性更小.     

On near optimal neural control of multiple-input nonlinear systems

It has been a common consensus that general techniques for stabilization of nonlinear systems are available only for some special classes of nonlinear systems. Control design for nonlinear systems with uncertain components is usually carried out on a per system basis, especially when physical control constraints, and certain control performance measures such as optimum time control are imposed. Elegant adaptive control techniques are difficult to apply to this type of problems. A new neural network based control design is proposed and presented in this paper to deal with a special class of uncertain nonlinear systems with multiple inputs. The desired system dynamics are analyzed and utilized in the process of the proposed intelligent control design. The theoretical results are provided to justify the design procedures. The simulation study is conducted on a second-order bilinear system with two inputs and uncertainties on its parameters. The simulation results indicate that the proposed design approach is effective.