反推自适应控制与滑模控制在交流伺服电机中的应用比较

针对AC伺服电机系统,在转矩及转动惯量变化情况下,对比反推自适应控制和滑膜控制两种方法在系统参数变化和阻力扰动的鲁棒性。仿真情况包括理想模型、摩擦力扰动、执行器饱和等。仿真结果表明反推自适应控制对系统变化具有很强鲁棒性,但是更容易受到执行器饱和影响;滑模控制方法更容易实现,但是在摩擦扰动存在情况下,振动式冲击难以消除。     

交流伺服系统的模糊自适应PID控制研究

交流伺服系统是一个非缌陛、多变量、强耦合的系统,采用传统的PID控制和普通模糊控制方法,难以达到理想的控制效果。通过设计一种模糊PID控制器,应用模糊算法在线自动整定PID参数的方法,将其应用于交流伺服系统位置调节器。仿真结果表明：模糊自适应PID控制方法具有较强的自适应能力和抗负载扰动能力,动态响应速度、稳定性等均优于常规PID控制和普通模糊控制,从而满足了交流伺服系统较高的控制要求和控制效果。     

放大电路负载线的研究与理解

从负载线的内涵出发,诠释了负载线的概念,列举了几类负载线,并总结了有载交流负载线的方程,提出了两点法画交流负载的办法。     

Detection of replay attacks in cyber-physical systems using a frequency-based signature

This paper proposes a frequency-based approach for the detection of replay attacks affecting cyber-physical systems (CPS). In particular, the method employs a sinusoidal signal with a time-varying frequency (authentication signal) into the closed-loop system and checks whether the time profile of the frequency components in the output signal are compatible with the authentication signal or not. In order to carry out this target, the couplings between inputs and outputs are eliminated using a dynamic decoupling technique based on vector fitting. In this way, a signature introduced on a specific input channel will affect only the output that is selected to be associated with that input, which is a property that can be exploited to determine which channels are being affected. A bank of band-pass filters is used to generate signals whose energies can be compared to reconstruct an estimation of the time-varying frequency profile. By matching the known frequency profile with its estimation, the detector can provide the information about whether a replay attack is being carried out or not. The design of the signal generator and the detector are thoroughly discussed, and an example based on a quadruple-tank process is used to show the application and effectiveness of the proposed method.     

Analysis and design of quadratic parameter varying (QPV) control systems with polytopic attractive region

This paper proposes a gain-scheduling approach for systems with a quadratic structure. Both the stability analysis and the state-feedback controller design problems are considered for quadratic parameter varying (QPV) systems. The developed approach assesses/enforces the belonging of a polytopic region of the state space to the region of attraction of the origin, and relies on a linear matrix inequality (LMI) feasibility problem. The main characteristics of the proposed approach are illustrated by means of examples, which confirm the validity of the theoretical results.     

电机矢量控制方法研究

介绍了四种异步电机矢量控制方法,分析了各种方法的优缺点,指出各种方法的适用场合。     

一种基于H.264标准的鲁棒性视频水印算法

文章研究了一种基于H.264低比特率视频流的鲁棒性盲水印算法,该算法首先对水印图像进行处理,以此来提高水印的安全性和鲁棒性。然后在I帧内亮度子块DCT系数的AC分量中,根据一定的判定条件嵌入水印,通过自适应地调整局部增益控制因子,使水印嵌入具有一定自适应性。仿真结果表明该算法具较好的不可见性和鲁棒性。     

基于PWM控制的单相SVG装置设计

分析了SVG(Static Var Generator)的工作原理,详细阐述了其控制策略及通过硬件电路的实现方法,最后通过实验验证了所提出的控制方法的有效性,以及将SVG应用于低压动态无功补偿领域的可行性。     

交流负反馈AGC电路设计

本文提出了一种可靠的ＡＧＣ电路——交流负反馈ＡＧＣ电路。文章阐述了其工作原理及电路设计思路，并设计出具体的电路供读者参考。     

基于ControlNet的PowerFlex700变频器实验开发

变频器是工业调速传动领域中应用很广泛的设备之一。PowerFlex700变频器是Rockwell自动化公司最新的产品。在Rockwell现场总线网络控制平台上,采用Rockwell的PLC和组态软件,编写变频调速控制梯形图,并进行对应的远程控制设计,设计并实现了Powerflex700变频器控制电机变频调速的综合实验。