分布式仿真鲁棒性改进方法

分布式计算方式可以有效地利用各级调度中心的计算资源和数据资源,实现大规模互联电网一体化仿真分析.在调度中心之间的广域网络中实施的分布式仿真,会受到各种不确定因素的干扰,从而导致计算中断或结果不正确.因此,提高分布式仿真系统的抗干扰能力,即鲁棒性,是使其实用的必要条件.为了在数据交换出现随机无规则类错误的情况下仍能得到精度可知的分布式仿真结果,提出了一种分布式仿真系统鲁棒性改进方法.该方法包含受扰信号辨识、拟边界条件替代以及仿真结果精度评估3个环节,适用于基于边界协调方程迭代求解的各类分布式仿真应用.针对IEEE标准系统的测试算例表明,所提出的方法对随机无规则类数据交换错误情况有效,可帮助分布式仿真系统得到更具工程应用价值的仿真结果,从而使其具有更高的鲁棒性和实用性.     

一种层级化的人眼检测方法

为了提高人眼检测算法的鲁棒性和实时性,提出了一种层级化的人眼检测方法.首先,该方法通过融合人脸检测器和肤色模型在图像大范围内进行快速人脸检测.然后,根据人脸面部拓扑结构几何关系的先验知识粗定位人眼得到人眼的粗定位区域.最后通过融合人眼检测器和人眼模板在人眼粗定位区域实现人眼的精确定位.大规模比较实验表明所提出方法能够准确定位人眼,并能够适用于人脸大小和旋转的变化,具有更强的鲁棒性.     

表面式永磁同步电机无源非奇异快速终端滑模控制

考虑逆变器非线性因素对调速系统的影响,从能量和鲁棒性的角度研究了表面式永磁同步电机(SPMSM)调速系统.首先推导了包含逆变器的SPMSM系统统一端口受控耗散哈密顿系统(PCHD)数学模型,基于能量成形方法和PCHD原理,设计了SPMSM调速系统的无源控制器,简化了控制算法,保证了系统全局稳定,逆变器非线性扰动由扩张状态观测器进行补偿.针对速度外环响应速度慢、鲁棒性差的问题设计了非奇异快速终端滑模速度控制器并得到q轴期望的电流.仿真和实验结果表明,所提控制方法使转速跟踪速度快、鲁棒性强,提高了整个系统的动静态性能.     

基于自抗扰控制器的无刷直流电动机速度控制

无刷直流电动机作为一个多变量强耦合非线性系统,采用经典PID控制难以得到满意的控制效果.采用自抗扰控制器来提高无刷直流电动机控制系统的动态性能和鲁棒性,自抗扰控制器设计过程中不需要对象模型结构和参数的精确信息.实验比较了PI控制器和自抗扰控制器的控制效果,结果表明自抗扰控制器(ADRC)对外部扰动和电动机参数的变化具有较强的鲁棒性.     

一种基于模型参数自适应理论的异步电动机转子电阻辨识实验研究

矢量控制系统的性能很大程度上依赖于电动机参数的准确测量,而异步电动机的转子电阻在运行中由于温升、集肤效应等原因,往往是电机控制系统中变化最为明显的参数之一.怎样快速、准确地辨识异步电动机的转子电阻,以提高整个控制系统的鲁棒性一直是国内外研究的重点.提出了一种基于模型参考自适应的转子电阻辨识方法.以瞬时无功功率作为模型,通过自适应调节得到所需的转子电阻参数.仿真和实验结果表明,这种方法可以准确、快速辨识转子电阻,并且提高了系统的鲁棒性.     

改进型PSO在过热汽温PID控制系统中的应用

通过采用改进的粒子群优化(PSO)算法对锅炉过热汽温中的PID参数进行优化,分析了传统过热汽温控制方案的不足,提高了整个系统的鲁棒性.该方法的应用使得过热汽温得到了良好的控制,提高了经济运行效益,同时也说明了改进的粒子群算法寻优简单,能够使控制系统获得较好的动态特性和很强的鲁棒性,易于并行化.仿真结果表明,该算法是一种...     

BLDCM调速系统滑模控制技术研究

滑模控制是一种性能优良的控制算法,用于BLDCM调速系统,并在MATLAB环境下进行仿真研究.仿真结果表明,系统速度响应快速平稳,在控制器参数和负载变化较大的情况下,均能保持较高的稳态精度,具有较强的鲁棒性.采用的连续开关函数有效抑制了系统的高频抖振,并得到了实验验证.     

基于零序电压注入的三电平中点电位平衡控制

中点电位不平衡是三电平逆变器的固有问题.针对此问题,基于零序电压注入原理,提出了一种中点电位平衡控制方法,给出了零序电压的选择原则.仿真及实验结果表明,该方法可以保证逆变器在多种状态时,中点电位都能得到有效控制,具有控制方法简单,鲁棒性强的特点.     

基于新型磁链观测模型的矢量控制系统研究

在异步电动机数学模型的基础上,介绍了一种改进的定子磁链观测方法,并在此基础上设计了转速估算器.磁链观测器和速度估算器结合起来应用于无速度传感器的矢量控制系统.通过Matlab仿真试验,得到转速、转矩、定子电流及其磁链等的仿真波形.仿真结果验证了该控制方法具有较好的动态响应和较强的鲁棒性.     

异步电机矢量控制中扩展卡尔曼滤波器的优化研究

利用扩展卡尔曼滤波器,将转速看成一个状态量,根据定子的电流和电压值估算转速.通过仿真对滤波器初值的选取进行了研究,得到优化的卡尔曼滤波器.试验结果表明,速度估算的准确性高,系统对于电机参数的变化不敏感,具有较强的鲁棒性.     

Evolution of intelligent control in adaptive systems

The evolution of adaptive control systems is considered from the viewpoint of the use of informatics and artificial intelligence (AI) tools. Some general principles of intellectronics (AI tools) are discussed taking into consideration adaptive control systems with non-linear dynamics operating under conditions of uncertainty. The principles are illustrated by an analytical review of adaptive-intelligent robot control and logical-probabilistic decision rules as applied to expert systems of adaptive control. Example of the use of intellectronics in adaptive systems are given.     

Adaptive identification and control of linear periodic systems using second‐level adaptation

At the present time, there is a great deal of interest in the adaptive control of systems with rapidly varying parameters. Such problems arise in different forms and in many disciplines including finance, sociology, biology, and engineering. In general, these problems are intractable mathematically and the time variations have to be classified in some form to obtain rigorous results. In this paper, we consider the adaptive identification and control of linear systems with periodically varying parameters (referred to as linear time‐varying periodic (LTP) systems). The class of systems with known periodic parameters has been investigated widely since the pioneering work of Floquet and lends itself to rigorous mathematical analysis. However, very little was known until the early years of the last decade concerning the adaptive control of such systems. The problem was introduced by Xu and explored in detail by Narendra and Zhiling in 2006 and 2009, respectively. In 2012, a new method was introduced in adaptive control by Han and Narendra and is referred to as second‐level adaptation. In this paper, the adaptive identification and control of LTP systems using second‐level adaptation is discussed.     

Simple adaptive control of uncertain systems

This paper considers adaptive control of various systems with unknown time-varying or non-linear dynamics in an attempt to show that practical adaptive control can be simple and robust. The simplified adaptive control methodology used is based on the observation that most real-world systems, even non-stationary or non-linear, can be stabilized by simple controller configurations. More complex controllers may be needed only in order to improve the performance of the control systems. In the adaptive scheme, the stabilizability properties of the plants are used only to satisfy the necessary conditions that guarantee robustness of simple adaptive controllers. The desired performance is then imposed upon the plant by these adaptive controllers, which force the plant to follow the input-output behaviour of low-order reference models. Examples from the recent literature of control with uncertainty are used to illustrate the power of these adaptive techniques.     

电弧炉电极调节系统自适应控制的仿真研究

研究了电弧炉电极调节系统的自适应控制问题。首先得出了电极调节系统的模型,然后将系统非线性的传递算子用线性的传递函数序列等效表示,在此基础上得到了模型参考自适应控制的方案。仿真结果表明自适应控制比ＰＩＤ控制有更好的动态性能,对弧长扰动的抑制能力大大增强。     

一类不确定非线性系统的自适应模糊滑模控制

针对一类不确定非线性系统自适应模糊控制中,为了保证系统稳定性而附加监督控制问题,根据滑模控制原理并利用模糊系统的逼近能力,提出了一种Ⅰ型间接自适应模糊滑模控制方法。该方法取消了监督控制,用滑模控制器增加了逼近误差的自适应补偿,李雅普诺夫稳定性理论分析证明,控制系统全局稳定且跟踪误差收敛到零。将这种控制器应用到过程控制的典型对象液位控制中,仿真结果表明了该控制器的有效性和可行性。     

Observer‐based adaptive control for stochastic nonstrict‐feedback systems with unknown backlash‐like hysteresis

This paper studies an observer‐based adaptive fuzzy control problem for stochastic nonlinear systems in nonstrict‐feedback form. The unknown backlash‐like hysteresis is considered in the systems. In the design process, the unknown nonlinearities and unavailable state variables are tackled by introducing the fuzzy logic systems and constructing a fuzzy observer, respectively. By using adaptive backstepping technique with dynamic surface control technique, an adaptive fuzzy control algorithm is developed. For the closed‐loop system, the proposed controller can guarantee all the signals are 4‐moment semiglobally uniformly ultimately bounded. Finally, simulation results further show the effectiveness of the presented control scheme.     

Adaptive actuator failure compensation design for unknown chaotic multi‐input systems

In this paper, an adaptive control approach is designed for compensating the faults in the actuators of chaotic systems and maintaining the acceptable system stability. We propose a state‐feedback model reference adaptive control scheme for unknown chaotic multi‐input systems. Only the dimensions of the chaotic systems are required to be known. Based on Lyapunov stability theory, new adaptive control laws are synthesized to accommodate actuator failures and system nonlinearities. An illustrative example is studied. The simulation results show the effectiveness of the design method. Copyright © 2014 John Wiley & Sons, Ltd.     

多机系统的非线性自适应分散稳定控制

针对含有未知参数的励磁系统,提出了一种非线性自适应控制设计方法,通过递推方法得到了自适应控制策略,而且在控制策略中包含了对未知参数的动态估计,最后获得了多机系统的非线性自适应分散励磁控制策略的一般表达式,在控制策略中所有的变量都是可量测的,而且控制量只与本机组的状态量有关,与其他机组的状态量和输电网络的参数无关,因此控制策略具有分散性和适应性,在一个６机系统上的仿真结果表明了非线性自适应控制器的有     

静态无功补偿器鲁棒控制的一种新自适应逆推方法

针对一般的参数反馈型非线性系统提出了一种扩展自适应逆推方法。该方法不仅保留系统的非线性特性和对未知参数的实时在线估计,而且突破了经典的确定性等价性原理。将该方法应用到含有未知参数带有静态无功补偿器 (SVC)的单机无穷大系统。将这种新自适应机制引入电力系统,得到了带有SVC单机无穷大系统的自适应控制律。仿真结果表明,该方法在提高系统稳定性和参数估计方面优于传统的逆推方法,为工程应用提供了一种有效的选择。另外, 该文中的算法可以应用到其他控制系统。     

Analysis of sticking regions in adaptive systems

We examine convergence properties of errors in a class of adaptive systems that correspond to adaptive control of linear time‐invariant plants with state variables accessible. We demonstrate the existence of a sticking region in the error space where the state errors move with a finite velocity independent of their magnitude. We show that these properties are exhibited by adaptive systems with closed‐loop reference models, which have been demonstrated to exhibit improved transient performance. A simulation study is included to illustrate the size of this sticking region and its dependence on various system parameters. With the existence of sticking regions shown for inner‐loop adaptive controllers, its impact on outer‐loop control is demonstrated for systems that implement inner‐loop adaptation. A flight control example is presented to illustrate this impact of sticking in a practical application.