连续时间T-S模糊系统的一种二次镇定方法

模糊隶属函数是模糊系统的重要组成部分,在系统镇定中考虑其结构和参数信息可以减少结果的保守性.为此,针对连续时间T-S模糊系统的二次镇定问题,提出一种新的放松二次镇定条件.运用一种有效的附加变量引入方式将隶属函数乘积界这一信息更好地纳入系统的镇定条件中,得到了比以往文献保守性更小的结果.所有结果均以线性矩阵不等式形式给出.仿真结果验证了所提出方法的有效性.     

基于观测器的不确定T-S模糊系统鲁棒镇定

为带有参数不确定性的T-S模糊控制系统提出了新的基于观测器的鲁棒输出镇定条件. 该条件用来设计模糊控制器和模糊观测器. 为了设计模糊控制器和模糊观测器, 用T-S模糊模型来表示非线性系统, 并运用平行分布补偿观念. 充分条件基于二次Lyapunov函数, 通过将模糊系统的鲁棒镇定条件表述为一系列矩阵不等式, 比以往文献中列出的条件具有更小的保守性. 该不等式为双线性矩阵不等式, 可分两步骤先后解得使T-S模糊系统镇定的控制器增益和观测器增益. 最后, 通过对一个具有不确定性的连续时间非线性系统控制的例子证明了提出方法比以往方法更宽松.     

改进的T-S 模糊模型鲁棒稳定条件及其在转台控制中的应用

提出了参数不确定T-S 模糊系统的新型鲁棒镇定条件．该条件表示为线性矩阵不等式（LMI）的形式, 将模糊子系统的相互关系收集到一系列矩阵而不是单个矩阵中,因此比近期刊出文献中的宽松二次镇定条件具有更 小的保守性．以该LMI 条件为基础,容易得到不确定T-S 模糊控制系统的状态反馈鲁棒镇定控制器．由于只涉及一 组LMI,控制器设计简单并易于数值求解．在转台这一具有参数不确定性的连续时间非线性系统的控制中,所提方 法的有效性得到成功验证．     

一种改进的T-S模糊系统稳定性分析方法

提出一种改进的方法以降低T-S模糊系统稳定性判定方法的保守性.通过定义有效最大交叠规则组(EMORG),提出一个改进的充分条件以保证模糊模型全局二次渐近稳定.此条件仅需在每个有效最大交叠规则组内分别寻找一个局部公共正定矩阵.以往的稳定性判定方法作为特例被包含在所提出方法中.仿真结果验证了该方法的有效性.     

二维多项式非线性系统的镇定控制研究

针对二维多项式非线性系统,提出了基于特征根负定配置的镇定控制方法.引入自由多项式,克服系统状态矩阵描述的不惟一性,进而降低控制综合问题求解的保守性.将特征根负定配置问题转化成多项式正定性验证问题,控制器设计问题通过多项式分解最终可由半定规划工具数值求解.在所提出的处理方法的基础上,讨论了4类二维多项式非线性系统的镇定控制问题.仿真结果验证了所提出方法的有效性.     

T-S模糊时滞系统的时滞相关镇定

基于T-S模糊模型方法,研究一类非线性区间时滞系统的稳定性分析与镇定问题,基于一组线性矩阵不等式的可解性,给出了非线性时滞系统时滞相关稳定和镇定的充分条件,并通过构造新的模糊权依赖型Lyapunov泛函,降低了稳定性准则的保守性,最后通过仿真例子表明了所提方法的有效性.     

T-S模糊系统的有限时间控制

面向具有强非线性的复杂工业过程,利用T-S模糊模型逼近原非线性系统,把T-S模糊模型逼近非线性系统存在的误差描述成有界时变的扰动,进而提出带扰动的T-S模糊系统的有限时间控制方法.首先,给出线性系统有限时间有界性的一个充分条件,与现有结果相比,该条件具有较小的保守性,并可以处理扰动是时变的情况;然后,提出T-S模糊系统有限时间镇定控制器的设计方法;最后,给出基于线性矩阵不等式(LMI)的控制器设计算法,并通过数值算倒演示所给方法的有效性.     

一种有效的不确定分数阶T-S模糊系统的控制器设计方法

考虑分数阶非线性系统的稳定和镇定问题,基于线性矩阵不等式(LMI)方法,对分数阶T-S模糊系统进行研究.利用并行分布补偿法,设计分数阶T-S模糊系统的控制器.考虑阶次满足$0<\alpha<1$的分数阶系统,给出可以利用Matlab求解的LMI形式的T-S模糊控制器设计镇定判据.该判据的优点是可以处理具有正实部特征根的分数阶T-S模糊系统的稳定性和镇定问题,能够保持与Matignon分数阶系统稳定性结论的一致性,并克服其他方法只能处理特征根在负实部的方法的局限性和保守性.数值仿真结果验证了所提控制器设计方法的有效性.     

Takagi-Sugeno模糊连续系统的模糊采样控制

研究了T-S模糊连续系统的模糊采样控制问题．利用广义系统的描述方法、Lyapunov-Krasovikii泛函以及线性矩阵不等式(LMI)方法,建立了LMIs形式的依赖于采样时间间隔的模糊采样镇定条件,同时给出了模糊采样控制律的设计方法．所设计的模糊采样控制律可以镇定T-S模糊系统．而且,当连续时间模糊控制律可以镇定T-S模糊系统时,对于足够小的采样时间间隔,带有同样增益矩阵的模糊采样控制律也可以镇定T-S模糊系统．最后,通过两个仿真实例说明了所给方法的有效性．     

一般齐次T-S模糊系统的逼近性能

为剖析一般齐次T-S模糊系统的逼近性能,通过广泛总结常用模糊集的特点,明确定义了一种具有普遍意义的输入空间的一般模糊划分(GFP).基于输入采用GFP的一般齐次T-S模糊系统的解析结构,证明了该类一般齐次T-S模糊系统能够以任意精度逼近任意非线性函数,并得到了一个其作为通用逼近器的充分条件.作为GFP的一种退化,进一步研究了输入采用线性模糊划分(LFP)的一般齐次T-S模糊系统的一阶逼近性能.仿真实例验证了所得理论结果的有效性,并考察了充分条件的保守性.这为基于齐次T S模糊模型的复杂系统建模与控制提供了理论指导.     

基于新的松弛条件的离散时间2-D T-S模糊系统的镇定

研究了在实际中有广泛应用的罗斯勒型离散时间非线性2-D系统的镇定问题. 首先, 运用离散时间2-DT-S模糊模型来对所研究的非线性2-D系统进行建模. 其次, 通过利用放松二次镇定技术得到新的关于2-D系统的二次镇定条件. 然后, 为了继续减少结果的保守性, 通过利用一个新的参数依赖李亚普诺夫函数、矩阵转换技术和松弛技术, 得到了新的非二次镇定条件. 最后, 用一个仿真例子来验证了结果的有效性.     

Relaxed delay-dependent stabilization criteria for discrete-time fuzzy systems based on a switching fuzzy model and piecewise Lyapunov functions

This paper presents delay-dependent stability analysis and controller synthesis methods for discrete-time Takagi-Sugeno （T-S） fuzzy systems with time delays. The T-S fuzzy system is transformed to an equivalent switching fuzzy system. Consequently, the delay-dependent stabilization criteria are derived for the switching fuzzy system based on the piecewise Lyapunov function. The proposed conditions are given in terms of linear matrix inequalities （LMIs）. The interactions among the fuzzy subsystems are considered in each subregion, and accordingly the proposed conditions are less conservative than the previous results. Since only a set of LMIs is involved, the controller design is quite simple and numerically tractable. Finally, a design example is given to show the validity of the proposed method.     

基于切换模糊模型和分段Lyapunov函数的T-S模糊系统时滞依赖H∞控制

研究了离散时滞T-S模糊系统的H无穷控制问题. 首先, T-S模糊系统被转换成等价的切换模糊系统, 基于分段Lyapunov函数, 给出了该系统带有H无穷性能的时滞依赖稳定化控制方法. 所得结论可以用一组线性矩阵不等式表示. 由于考虑了子系统间的相互关系, 因此所得结论较以往结果具有更小的保守性. 最后, 仿真例子说明了所提方法的有效性.     

离散模糊大系统的分散化PDC 控制器设计: LM I 方法

考虑了由N个相互关联的T—S子模糊系统组成的离散模糊大系统的分散镇定问题，给出了保证该模糊大系统闭环渐近稳定的分散化并行分布补偿(DPDC)控制器的设计方法，这些DPDC控制器的存在条件均以LMI的形式出现，LMI可通过MATLAB的LMI工具箱求解，因此提供了一条综合离散模糊大系统分散化PDC控制器的有效途径，仿真例子说明了所提出方法的有效性。     

Polynomial Fuzzy Observer Designs: A Sum-of-Squares Approach

This paper presents a sum-of-squares (SOS) approach to polynomial fuzzy observer designs for three classes of polynomial fuzzy systems. The proposed SOS-based framework provides a number of innovations and improvements over the existing linear matrix inequality (LMI)-based approaches to Takagi-Sugeno (T-S) fuzzy controller and observer designs. First, we briefly summarize previous results with respect to a polynomial fuzzy system that is a more general representation of the well-known T-S fuzzy system. Next, we propose polynomial fuzzy observers to estimate states in three classes of polynomial fuzzy systems and derive SOS conditions to design polynomial fuzzy controllers and observers. A remarkable feature of the SOS design conditions for the first two classes (Classes I and II) is that they realize the so-called separation principle, i.e., the polynomial fuzzy controller and observer for each class can be separately designed without lack of guaranteeing the stability of the overall control system in addition to converging state-estimation error (via the observer) to zero. Although, for the last class (Class III), the separation principle does not hold, we propose an algorithm to design polynomial fuzzy controller and observer satisfying the stability of the overall control system in addition to converging state-estimation error (via the observer) to zero. All the design conditions in the proposed approach can be represented in terms of SOS and are symbolically and numerically solved via the recently developed SOSTOOLS and a semidefinite-program solver, respectively. To illustrate the validity and applicability of the proposed approach, three design examples are provided. The examples demonstrate the advantages of the SOS-based approaches for the existing LMI approaches to T-S fuzzy observer designs.     

An observer-based approach to controlling time-delay chaotic systems via Takagi-Sugeno fuzzy model

This study presents a fuzzy model-based control criterion for time-delay chaotic systems with uncertainty. The Takagi-Sugeno (T-S) fuzzy model is adopted for representing a chaotic system possessing a time delay. A unified approach for designing a fuzzy observer, which integrates parallel distributed compensation with an adaptive updating method, is first discussed. An observer-based fuzzy control scheme is then developed to deal with stabilization and tracking problems. Based on Lyapunov stability analysis, sufficient conditions that ensure robust control performance of time-delay chaotic systems are derived. These conditions are represented in terms of linear matrix inequalities and adaptive updating laws. Finally, the proposed approach is validated through numerical synchronization, stabilization, and model tracking control simulations.     

New approaches to relaxed stabilization conditions and H-infinity control designs for T-S fuzzy systems

This paper focuses on the problem of fuzzy control for a class of continuous-time T-S fuzzy systems.New methods of stabilization design and H infinity control are derived based on a relaxed approach in...     

Relaxed stabilization conditions for continuous-time Takagi-Sugeno fuzzy control systems

This paper deals with the stabilization of continuous-time Takagi-Sugeno (T-S) fuzzy control systems. Based on fuzzy Lyapunov functions and nonparallel distributed compensation (non-PDC) control laws, new stabilization conditions are represented in the form of linear matrix inequalities (LMIs). The theoretical proof shows that the proposed conditions can provide less conservatism than the existing results in the literature. Moreover, in order to demonstrate the effectiveness of the non-PDC control laws, the problem of H_∞ controller design for T-S fuzzy systems is also studied. Simulation examples are given to illustrate the merits of the proposed methods.