一种改进的非线性积分器及应用

本文针对非线性积分器工程设计中的几个问题，提出了一种可以不要求系统开环频率特性具有良好低通特性的改进非线性积分器，并对该非线性积分器进行了详细的分析，仿真结果证明该非线性积分的有效性。     

海杂波的非线性测试

时间序列的非线性检测对于非线性时间序列分析、混沌特性研究有着重要意义。讨论了时间序列的几种非线性检测方法,将代理数据产生方法中的IAAFT方法与冗余方法结合起来,对实测海杂波数据进行非线性检测。对测试结果进行分析,表明海杂波是由非线性系统产生的,应该采用非线性处理方法研究海杂波。     

一类非线性系统的自组织模糊CMAC神经网络自适应重构跟踪控制

提出了一种非线性系统的自组织模糊CMAC(SOFCMAC)神经网络自适应重构跟踪控制方法,首先通过构造增广系统,设计出线性渐近跟踪控制器,然后采用SOFCMAC神经网络在线重构系统的非线性特性,以消除非线性特性引起的系统误差,可保证非线性系统闭环稳定并使系统输出跟踪期望输出.仿真算例证明了SOFCMAC神经网络自适应重构跟踪控制系统的稳定性.     

一类不确定非线性系统具有扇形非线性输入的鲁棒几乎干扰解 …

研究了一类具有不确定非线性输入,结构亦不确定的非线性系统的鲁棒几干扰解耦问题。在非线性输入的扇形界及不确定性特性已知的条件下,所设计的控制器能保证闭环系统从干扰到输出的Ｌ２－增益保持在给定水平上。     

具有任意非线性输入的鲁棒模型参考自适应控制

提出了一种分析具有任意非线性输入的模型参考自适应(MRAC)的新方法,它不要 求对象是稳定的,允许系统存在未建模动态和有界扰动.同时给出了一种提高非线性输入自 适应系统特性的补偿方案,它通过在控制律中引入跟踪误差,可以提高系统的暂态及稳态精 度,而又不破坏MRAC系统的收敛特性.     

导弹交流电动舵机的非线性解耦控制与仿真

针对交流电动舵机系统非线性,多变量和强耦合的特性,提出了一种基于微分几何方法和变结构控制理论的非线性解耦控制方法。建立了交流电动舵机的非线性模型,利用微分几何理论,通过对系统进行微分同胚变换和反馈变换,实现了非线性系统的精确线性化和输入/输出解耦,并针对电动舵机系统参数摄动和负载扰动的特点,利用指数趋近律设计了电动舵机的变结构控制器。仿真结果表明不仅可以有效地实现交流电动舵机系统的非线性解耦,具有良好的静、动态特性。     

基于Preisach模型的迟滞系统建模与控制

针对一种复杂的非线性系统一迟滞系统,研究了基于KP算子Preisach模型对迟滞系统进行建模的方法。利用Preisach模型与其边界线之间的映射关系,建立了容易在线更新的迟滞模型。基于Preisach模型进行迟滞非线性系统的控制,采用PID方法来控制一类带有未知非线性特性迟滞的单输入单输出非线性系统。对迟滞非线性系统的建模与控制进行的数值仿真研究结果表明,该迟滞非线性系统的建模和控制方法具有理论意义和应用价值。     

含有齿隙非线性的动态系统的辨识

本文提出了带有齿隙非线性输入的离散时间线性动态系统的参数估计算法,对含有齿隙非线性的动态系统中齿隙非线性特性参数的辨识问题给出了一种简单的解决方法,并通过仿真验证了该方法的有效性和实用性.     

前言

<正>在自然界中,由于扰动、误差及各种人为、环境因素的存在,任何实际生产生活中的系统都在不同程度上具有某种非线性特性,比如飞行器系统、工业生产和电力系统等.然而,大多数关于非线性系统的分析或设计问题很难在线性系统理论的框架下得到圆满解决.因此,近几十年来,非线性系统的分析与设计问题成为控制领域的研究重点.随着科技的高速发展,控制系统变得越来越复杂,其非线性特性越来越强,对控制器的性能要求也越来越高,非线性系统理论受到相当大的挑战.同时,机器人的发展,宇宙飞行器、直升飞机、大型柔性结构的控制,都是非常复杂的非线性系统问题,这就促使非线性系统的分析与设计理论需要得到进一步研究和发展.     

高精确度非线性数字面板表

一、概述在自动测量和自动控制系统中,由于传感器本身固有的非线性,常常影响到整个系统的测量精确度和控制精确度。因而,对传感器的非线性输出进行线性化处理,是保证整个系统测量精确度所必须采取的措施。目前,对于传感器的线性化处理,一般采用模拟分段折线化、模拟器件特性化、计算法、插值法、查表法等几种方法。前两种方法成本低,精确度也低,后三种方法精确度高,但需计算机,对于无计算机的用户有一定的困难。下面介绍的高精度非线性数字面板表,就是一种既不使用计算机,又有较高精确度,造价也不高的线性化方法。二、非线性面板表原理简介非线性面板表采用了查表法,利用"单板机"将表格内容事先写入EPROM,从而实现传感器的线性化处     

On asymptotic stabilisation of a chain of integrators with nonlinearity and an uncertain input delay by output feedback

In this paper, we provide an output feedback solution over one given by Choi and Lim [Systems & Control Letters, 59(6), 374–379 (2010)] under more generalised system set-up. More specifically, we consider a stabilisation problem of a chain of integrators that has nonlinearity and an uncertain delay in the input by output feedback. The nonlinearity is classified into four types. Then, we propose a memoryless output feedback controller which contains a gain-scaling factor to adjust controller gains depending on the given nonlinearity type. Our stability analysis shows that the controlled system has unique stabilisation result associated with each type of nonlinearity. Our result provides a new aspect to the stabilisation problem of nonlinear time-delay systems and broadens the existing control results of time-delay systems. Two examples are given for illustration.     

Performance evaluation of nonlinear weighted T-system

This article deals with the analysis of discrete event systems which can be modelled by timed event graphs with multipliers (TEGMs). These graphs are an extension of weighted T-systems studied in the Petri net literature. These models do not admit a linear representation in (min,?+) algebra. This nonlinearity is due to the presence of weights on arcs. To mitigate this problem of nonlinearity and to apply some basic results used to analyse the performances of linear systems in dioid algebra, we propose a linearisation method of mathematical model reflecting the behaviour of a TEGM in order to obtain a (min,?+) linear model.     

Consensus of multi-agent systems with dead-zone nonlinearity

In this paper, we investigate the consensus problem of multi-agent systems with dead-zone nonlinearity over undirected networks. Firstly, a control protocol is designed based on the local information of agents. Then by LaSalle??s invariance principle for non-smooth systems, we prove that if the undirected graph is connected then the consensus is achieved by the proposed control protocol. Secondly, sufficient conditions are given to guarantee the consensus of multi-agent systems with deadzone nonlinearity and switching topologies by Lyapunov method. Finally, numerical simulations show the effectiveness of our theoretical results.     

An improved treatment of saturation nonlinearity with its application to control of systems subject to nested saturation

This paper is concerned with the treatment of saturation nonlinearity existing commonly in practical control systems. An improved treatment of such nonlinearity is proposed, which includes the well-known linear differential inclusion method for handling saturation nonlinearity as a special case. To show the effectiveness of this new treatment, the problem of analysis and design of linear systems subject to nested saturation function is revisited. The proposed results not only complement the existing work on this problem, but also are less conservative than the existing methods. Four numerical examples are worked out to illustrate the applicability of the established approaches.     

Nonlinear control of Hammerstein systems with passive nonlineardynamics

A nonlinear dynamic compensator framework for Hammerstein systems with passive nonlinear dynamics is proposed. For this class of systems controlled by passive nonlinear dynamic compensators we prove the global closed-loop stability by modifying the dynamic compensator to include a suitable input nonlinearity. The proof of this result is based on the dissipativity theory and shows that the nonlinear controller modification counteracts the effects of the input nonlinearity by recovering the passivity of the plant and the compensator     

时变滞后Lurie型系统的改进稳定性准则

In this technical note, we present a new stability analysis procedure for ascertaining the delay-dependent stability of a class of Lurie systems with time-varying delay and sector-bounded nonlinearity using Lyapunov-Krasovskii (LK) functional approach. The proposed analysis, owing to the candidate LK functional and tighter bounding of its time-derivative, yields less conservative absolute and robust stability criteria for nominal and uncertain systems respectively. The effectiveness of the proposed criteria over some of the recently reported results is demonstrated using a numerical example.     

On Robust Approximate Feedback Linearization: Control with Two Gain-scaling Factors

In this paper, we consider a problem of global stabilization for a class of approximately feedback linearized nonlinear systems. In order to handle more nonlinearity over the existing results, we provide a new feedback controller with two gain-scaling factors and we show that more nonlinearity can be treated by our control scheme. Moreover, we analytically show that the considered nonlinear systems can be stabilized by the proposed controller. Through comparison practical examples, we illustrate the improved features of our proposed control method.

     

Proof of the circle criterion for state space systems via quadratic Lyapunov functions — Part 2

In Part 1 of this paper a detailed analysis of the stability of a closed-loop system containing a single nonlinearity was made. The analysis is repeated here, but with stronger assumptions on the nonlinearity. The class of Total Derivative matrices is introduced and the role played by this class in generating quadratic Lyapunov functions for certain dynamical systems is considered. A new approach for deriving stability criteria is presented which is equivalent to the path integral method of Brockett.     

互联非线性系统反馈主导控制设计方法及汽门开度控制应用

分析了电力系统非线性的数学性质,指出电力系统非线性是一种有界非线性.在此基础上,将反馈主导方法(feedback domination method,FDM)引入多机电力系统非线性控制.该方法与反馈线性化方法不同;反馈线性化方法是通过反馈将原非线性系统转化为线性系统,反馈主导方法则是通过反馈将原非线性系统转换为特定形式的非线性系统,该特定形式的非线性系统的动态由反馈引入的非线性部分主导.以多机系统非线性汽门控制问题为例,设计了反馈主导非线性汽门控制器,该控制器仅包含本地量测量,易于实现.数值仿真表明,多机系统反馈主导非线性汽门控制器可显著提高电力系统暂态稳定性.