基于RBF网络的参数自学习模糊控制的研究

模糊控制以其自适应性、鲁棒性和易于实现等优点得到广泛应用。然而模糊控制规则的获得通常由专家经验给出,这就存在诸如控制规则不够客观、专家经验难以获得等问题。在模糊控制系统中,模糊规则库的构建是至关重要的,因此研究模糊规则的自动生成有着重要的理论和应用价值。本文首先以模糊控制理论和RBF神经网络理论为基础,提出了一种能够有效表达模糊系统可解释性的RBF网络结构;然后详细讨论在此网络结构下提取模糊规则的学习算法;最后依据上述方法进行仿真实验,实验结果表明,这种根据测量数据自动提取模糊规则的方法是有效的。     

Fuzzy observer design using linear matrix inequalities for fuzzy closed-loop control systems

Linear observers play an important role in modern control theory and practice. A systematic design method of fuzzy observers would be important for fuzzy control as well. The fuzzy observer is designed by solving linear matrix inequalities (LMI) that represent control performance such as disturbance rejection and robust stability. Our approach in designing the fuzzy observer is based on the LMI formulation of the stability conditions for closed-loop Takagi-Sugeno (T-S) fuzzy systems, when states are not available for measurement of feedback. We present a new approach, which is to design an observer based on fuzzy implications, with fuzzy sets in the antecedents, and an asymptotic observer in the consequents. Each fuzzy rule is responsible for observing the states of a locally linear subsystem. An example illustrates the design procedure.     

一类非线性离散系统模糊控制器的分析和设计

针对一类非线性离散不确定系统,在系统状态不可测的情况下,以T-S模型描述不同状态空间的局部动态区域,并通过中心平均反模糊化、乘积推理、单点模糊化方法得到全局模糊系统模型.基于李亚普诺夫理论和线性矩阵不等式,设计了一种基于观测器的鲁棒控制器,并对离散状态下的此类系统进行了稳定分析.最后通过M ATLAB仿真,证明了该方法的有效性.     

A new hybrid methodology for cooperative-coevolutionary optimization of radial basis function networks

This paper presents a new multiobjective cooperative–coevolutive hybrid algorithm for the design of a Radial Basis Function Network (RBFN). This approach codifies a population of Radial Basis Functions (RBFs) (hidden neurons), which evolve by means of cooperation and competition to obtain a compact and accurate RBFN. To evaluate the significance of a given RBF in the whole network, three factors have been proposed: the basis function’s contribution to the network’s output, the error produced in the basis function radius, and the overlapping among RBFs. To achieve an RBFN composed of RBFs with proper values for these quality factors our algorithm follows a multiobjective approach in the selection process. In the design process, a Fuzzy Rule Based System (FRBS) is used to determine the possibility of applying operators to a certain RBF. As the time required by our evolutionary algorithm to converge is relatively small, it is possible to get a further improvement of the solution found by using a local minimization algorithm (for example, the Levenberg–Marquardt method). In this paper the results of applying our methodology to function approximation and time series prediction problems are also presented and compared with other alternatives proposed in the bibliography.     

创新设计的模糊综合评价

针对影响机械产品零部件创新设计品质的各种因素,结合目标树和层次分析法,提出产品创新设计的多级模糊综合评判过程的实现方法,并用方根法简化模糊评价的权重集求解过程。通过对设计模型的模糊综合评价验证该评价方法可行,评价结果客观,便于设计模型的评价和比较。     

一种基于改进T-S模糊推理的模糊神经网络学习算法

针对模糊神经网络学习算法计算量过大,在预测模型设计中提出了基于改进T-S模糊推理的模糊神经网络学习算法。主要工作如下:首先,改进T-S模糊推理方法,定义基于偏移率的T-s模糊推理方法;然后,通过将此模糊推理方法与基于合成规则的模糊推理方法及距离型模糊推理方法相比较可以看出,所提方法有较少的计算量,且比较有效;最后,在此基础上改善了模糊神经网络学习算法,并将其应用于天气预测与安全态势预测。测试结果表明,该方法明显改善了学习效率,减少了预测模型设计中的学习次数与时间复杂度,并降低了学习误差。     

径向基函数网络的功能分析与应用的研究

径向基函数网络与BP网络在网络结构上都属于前向网络,但它们对网络权值训练所采用的算法是完全不同的。另外,径向基函数网络的网络结构与模糊系统有很紧密的关联。该文从径向基函数网络的结构入手,分别对其所具有的特点、权值训练、网络设计方法及其应用等方面,通过分析与实例,采用对比的方式,给予实验的验证。     

交通灯的一种智能模糊控制系统

本文设计了一种新型交通灯智能模糊控制系统,突破了传统机械的定时模式,利用模糊控制算法对四相位三车道单交叉口的交通灯进行控制,可以依据实时交通流量灵活运行。通过模糊规则,即对当前等待队列长与通行队列长以模糊推理,得到最佳的绿灯延时时间。仿真结果表明模糊控制方法在车辆延误时间上较之传统定时控制方法大为改善,使公路利用率产生可观的经济效益。     

MATLAB在模糊控制系统仿真中的应用

模糊控制系统的设计是模糊控制系统应用的重要问题之一,而系统的仿真是设计中的重要步骤和必要的保证,本文首先简要介绍了MATLAB语言、模糊逻辑工具箱和SIMULINK工具箱,然后着重介绍如何利用模糊逻辑工具箱、SIMULINK工具箱进行模糊控制系统的仿真,并给出具体实例,这种方法克服了传统用C语言进行仿真的复杂,不方便的缺点,使模糊控制系统的仿真变得容易、直观且迅速。     

交通灯的一种智能模糊控制系统

本文设计了一种新型交通灯智能模糊控制系统，突破了传统机械的定时模式，利用模糊控制算法对四相位三车道单交叉口的交通灯进行控制．可以依据实时交通流量灵活运行。通过模糊规则，即对当前等待队列长与通行队列长以模糊推理，得到最佳的绿灯延时时间。仿真结果表明模糊控制方法在车辆延误时间上较之传统定时控制方法大为改善，使公路利用率产生可观的经济效益。     

Application of practical fuzzy arithmetic to fuzzy internal model control

This paper applies a new fuzzy arithmetic of interval calculus and fuzzy quantities to automatic control. Practical results are obtained which overcome those based on the extension principle or α-cuts. The proposed approach is based on a different representation of fuzzy numbers, though most common arithmetic operators cannot be directly applied for designing a fuzzy controller due to the unjustified overestimation effect. To avoid this phenomenon, a procedure based on an “exact” resolution calculus is proposed, whose solutions allow creating a fuzzy internal model control scheme. The validity of the new method is illustrated by a real-time educational engineering application on classical control design: a coupled tanks system.     

模糊控制在液位控制器中的应用

在模糊控制原理的基础上设计出模糊控制器,利用模糊推理的方法实现了对液位系统的控制,本文详细介绍了模糊控制器设计思路和步骤。并在MATLAB仿真软件上进行仿真研究,结果表明,模糊控制能使液位控制系统的控制效果大大提高,对进一步的研究应用提供了一定的参考价值。     

基于模糊控制的某教练机飞行姿态控制器设计

提出了一种基于规则的模糊逻辑飞行控制系统的设计方法,用以解决某教练机训练系统中数学模型时变性和不确定性问题.为了避免建模的困难,某教练机飞控系统采用模糊逻辑控制设计其控制律,结合飞行员的操纵经验,对系统进行动态调整.以俯仰角为研究对象,利用MATLAB中的fuzzy工具箱实现了模糊控制器设计,给出了俯仰角模糊控制器的控制曲面视图,并在SIMULINK仿真环境下建立了仿真模型.结果表明,所设计的模糊逻辑控制器满足操作品质的要求,具有较好的鲁棒性,对教练机驾驶训练仿真平台的飞行控制系统设计具有一定的应用价值.     

Fuzzy classifier design using genetic algorithms

A new method for design of a fuzzy-rule-based classifier using genetic algorithms (GAs) is discussed. The optimal parameters of the fuzzy classifier including fuzzy membership functions and the size and structure of fuzzy rules are extracted from the training data using GAs. This is done by introducing new representation schemes for fuzzy membership functions and fuzzy rules. An effectiveness measure for fuzzy rules is developed that allows for systematic addition or deletion of rules during the GA optimization process. A clustering method is utilized for generating new rules to be added when additions are required. The performance of the classifier is tested on two real-world databases (Iris and Wine) and a simulated Gaussian database. The results indicate that highly accurate classifiers could be designed with relatively few fuzzy rules. The performance is also compared to other fuzzy classifiers tested on the same databases.     

一种无抖动的模糊控制器

提出了一种新型的模糊控制器─—无抖动模糊控制器的设计方法。无抖动模糊控制器的输出为误差的分段线性函数，用它控制的系统工作平稳，稳态无抖动，控制精度高，解决了常规模糊控制系统存在的稳态抖动问题。     

基于模糊状态模型的连续系统控制器设计和稳定性分析

首先给出连续系统模糊状态模型的表示方法,在此基础上给出了一种模糊状态反 馈控制器的设计方法,对其稳定性进行了分析,得出了一个确保系统全局稳定的充分条件. 同时也提出一种模糊观测器的设计方法,并对其收敛性进行分析,得出了确保收敛的一个充 分条件.     

基于遗传算法的模糊控制器的综合优化设计

该文简要叙述了模糊控制器的优化设计原理,提出了一种采用遗传算法对模糊控制器的量化因子、比例因子、隶属函数的参数和模糊控制规则进行综合优化的设计方法,并采用VisualC++6.0编制了相应的软件,该软件已成功地应用于工程中。此外,该软件也可作为遗传优化和模糊控制器设计的辅助教学软件。     

基于PLC的模糊控制器的设计

通过对模糊控制器设计过程的分析,提出了基于PLC查表方式实现模糊控制的设计方法。给出了PLC程序设计的算法流程图及输入量量化程序、模糊控制表查询程序等关键步骤的梯形图。结果表明,用PLC实现的模糊控制器简单实用,具有广阔的应用前景。     

插值算法在模糊控制中的应用与仿真研究

该文针对目前某些模糊控制系统在控制过程中精度比较低的问题，将模糊控制系统离线得到的模糊控制表与双线性插值算法结合起来，提出一种新的基于在线插值的模糊控制系统的设计方法，用此方法使模糊控制器输入、输出值保持连续变化，以此来克服控制器因输入输出量化所造成的调节死区与可能出现的稳态等缺点，从而来达到提高模糊控制系统控制精度的目的。在某舰船控制系统的仿真例子说明了此方法的有效性。     

Simplifying the automatic design of a fuzzy logic controller using evolutionary programming

With the availability of a wide range of Evolutionary Algorithms such as Genetic Algorithms, Evolutionary Programming, Evolutionary Strategies and Differential Evolution, every conceivable aspect of the design of a fuzzy logic controller has been optimized and automated. Although there is no doubt that these automated techniques can produce an optimal fuzzy logic controller, the structure of such a controller is often obscure and in many cases these optimizations are simply not needed. We believe that the automatic design of a fuzzy logic controller can be simplified by using a generic rule base such as the MacVicar-Whelan rule base and using an evolutionary algorithm to optimize only the membership functions of the fuzzy sets. Furthermore, by restricting the overlapping of fuzzy sets, using triangular membership functions and singletons, and reducing the number of parameters to represent the membership functions, the design can be further simplified. This paper describes this method of simplifying the design and some experiments performed to ascertain its validity.