Pb(Mg_(1+x)/3Nb_(2-x)/3)O_3铁电材料中有序-无序相变的理论研究

基于Kikuchi自洽迭代方法,利用有序-无序相变理论,并取最近邻相互作用近似,研究了Pb(Mg_((1+x)/2)Nb_((2-x)/2)O_3晶粒中在x=0.5时有序区形成的原因,提出Mg~(2+)∶Nb~(5+)=1∶1(离子数比)时,形成B位有序排列最为有利,并且弱的空间电荷场不影响这种有序排列的形成,同时给出了温度-组份的有序-无序相图。     

Decentralized control: Status and outlook

This paper reviews state of the art in the area of decentralized networked control systems with an emphasis on event-triggered approach. The models or agents with the dynamics of linear continuous-time time-invariant state-space systems are considered. They serve for the framework for network phenomena within two basic structures. The I/O-oriented systems as well as the interaction-oriented systems with disjoint subsystems are distinguished. The focus is laid on the presentation of recent decentralized control design and co-design methods which offer effective tools to overcome specific difficulties caused mainly by network imperfections. Such side-effects include communication constraints, variable sampling, time-varying transmission delays, packet dropouts, and quantizations. Decentralized time-triggered methods are briefly discussed. The review is deals mainly with decentralized event-triggered methods. Particularly, the stabilizing controller–observer event-based controller design as well as the decentralized state controller co-design are presented within the I/O-oriented structures of large scale complex systems. The sampling instants depend in this case only on a local information offered by the local feedback loops. Minimum sampling time conditions are discussed. Special attention is focused on interaction-oriented system architecture. Model-based approach combined with event-based state feedback controller design is presented, where the event thresholds are fully decentralized. Finally, several selected open decentralized control problems are briefly offered as recent research challenges.     

Super-Resolution image Reconstruction Based on Iteration and Wavelet Transform

In this paper, we provide a super-resolution image reconstruction algorithm based on wavelet transform. Wavelet transform can separate high frequency and low frequency information of image. The more high frequency information can be obtained by using wavelet transform and the technique of image fusion. Meanwhile, reconstructed super-resolution image is produced by the iterative method. In iteration process, noise of image can be suppressed by applying method of wavelet threshold de-noising. The experiment results show that the algorithm can overcome the disadvantage of the classical interpolation method and effectively improve the resolution and PSNR of the image.     

基于AJAX技术创建的异步方法应用研究

遵循AJAX技术的基本原理,创建了一个简单的异步引用方法,并给出登录实例来说明如何实现该方法的引用,减少代码冗余。主要阐述了通过创建方法,并引用方法到不同Web应用程序中,实现了代码的优化。     

广角摄像机在机器人视觉定位中的应用

为了保证广角摄像机在现代机器人视觉定位应用中的准确性,以广角摄像机像素坐标的反畸变过程为研究对象,提出一种在畸变对应表的基础上使用中心迭代法以及区域插值法确定物体实际位置的方法。通过实验证明了该方法能够测量物体的位置,其精度能够满足工业使用要求。     

无拖曳卫星的推进器不确定下鲁棒控制器设计

以低轨环境下无拖曳卫星控制器设计为研究对象,对于给定结构的无拖曳卫星,考虑推进器增益存在不确定时的鲁棒控制器设计。首先,简要介绍无拖曳卫星的概念及原理;之后,对带有不确定性的无拖曳卫星控制系统进行分析与建模,并对其进行LFT不确定性建模,最后利用μ分析和D-K迭代设计出满足鲁棒性能的鲁棒控制器。仿真结果说明鲁棒控制器的有效性。     

Asynchronous fault detection filter design approach for discrete‐time switched linear systems

This paper is concerned with the problem of the fault detection filter design for discrete‐time switched linear systems with average dwell‐time. The designed fault detection filters are also switched systems, which are assumed to be asynchronously switched with the original switched systems. Improved results on the weighted l₂ performance and the H _? performance are first given, and the multiple Lyaounov‐like functions during matched period and unmatched period for the running time of one subsystem are used. By the aid of multiple Lyapunov‐like functions combined with Projection Lemma, the FD filters are designed such that the augmented systems under asynchronous switching are exponentially stable, and the residual signal generated by the filters achieves the weighted l₂‐gain for disturbances and guarantees the H _? performance for faults. Sufficient conditions are formulated by linear matrix inequalities, and the filter gains are characterized in terms of the solution of a convex optimization problem. Finally, examples are provided to demonstrate the effectiveness of the proposed design method. Copyright © 2012 John Wiley & Sons, Ltd.     

Fault detection for continuous‐time switched systems under asynchronous switching

In this paper, the problem of fault detection for continuous‐time switched systems under asynchronous switching is investigated. The designed fault detection filter is assumed to be asynchronous with the original systems. Attention is focused on designing a fault detection filter such that the estimation error between the residual and the fault is minimized in the sense of H _∞ norm. By employing piecewise Lyapunov function and average dwell time techniques, a sufficient condition for the existence of such a filter is exploited in terms of certain linear matrix inequalities. Finally, an example of a switched electrical circuit is provided to illustrate the effectiveness of the proposed approach. Copyright © 2013 John Wiley & Sons, Ltd.     

基于Pro/TOOLKIT异步模式特征识别方法

对Pro／Engineer（Pro／E）二次开发工具Pro／TOOLKIT（PTC公司为Pro／E软件提供的二次开发工具包）的异步模式进行了研究，充分利用参数化技术，开发了实体模型的特征识别系统。系统可以控制Pro／E的自动启动及关闭，使其在后台运行。通过模型的调用实现实体特征的快速识别提取，为模具估价系统的智能化设计做好了准备。     

基于MATLAB/SIMULINK的异步电动机软起动控制系统的仿真

针对异步电动机直接起动会产生很大起动电流的特性,提出了一种基于PID控制原理的异步电动机软起动控制方法。利用MATLAB/SIMULINK对此闭环控制系统建立了仿真模型并进行了仿真实验。仿真结果表明采用PID控制的软起动控制方法可以有效地限制异步电动机的起动电流,因此该控制方法是正确有效的。