Nonlinear systems design by a novel fuzzy neural system via hybridization of electromagnetism-like mechanism and particle swarm optimisation algorithms

In this paper, a hybrid of algorithms for electromagnetism-like mechanisms (EM) and particle swarm optimisation (PSO), called HEMPSO, is proposed for use in designing a functional-link-based Petri recurrent fuzzy neural system (FLPRFNS) for nonlinear system control. The FLPRFNS has a functional link-based orthogonal basis function fuzzy consequent and a Petri layer to eliminate the redundant fuzzy rule for each input calculation. In addition, the FLPRFNS is trained by the proposed hybrid algorithm. The main innovation is that the random-neighbourhood local search is replaced by a PSO algorithm with an instant-update strategy for particle information. Each particle updates its information instantaneously and in this way receives the best current information. Thus, HEMPSO combines the advantages of multiple-agent-based searching, global optimisation, and rapid convergence. Simulation results confirm that HEMPSO can be used to perform global optimisation and offers the advantage of rapid convergence; they also indicate that the FLPRFNS exhibits high accuracy.     

Recurrent neuro fuzzy control design for tracking of mobile robots via hybrid algorithm

This paper proposes a TSK-type recurrent neuro fuzzy system (TRNFS) and hybrid algorithm- GA_BPPSO to develop a direct adaptive control scheme for stable path tracking of mobile robots. The TRNFS is a modified model of the recurrent fuzzy neural network (RFNN) to obtain generalization and fast convergence. The TRNFS is designed using hybridization of genetic algorithm (GA), back-propagation (BP), and particle swarm optimization (PSO), called GA_BPPSO. For the tracking control of mobile robot, two TRNFSs are designed to generate the control inputs by direct adaptive control scheme and hybrid algorithm GA_BPPSO. Through simulation results, we demonstrate the effectiveness of our proposed controller.     

Output recurrent wavelet neural network-based adaptive backstepping controller for a class of MIMO nonlinear non-affine uncertain systems

In this paper, an adaptive backstepping control problem is proposed for a class of multiple-input-multiple-output nonlinear non-affine uncertain systems. An output recurrent wavelet neural network (ORWNN) is used to approximate the unknown nonlinear functions to develop the proposed adaptive backstepping controller. The proposed ORWNN combines the advantages of wavelet-based neural network, fuzzy neural network, and output feedback layer to achieve higher approximation accuracy and faster convergence. According to the estimation of ORWNN, the control scheme is designed by backstepping approach such that the system outputs follow the desired trajectories. Based on the Lyapunov approach, our approach guarantees that the system outputs converge to a small neighborhood of the references signals, that is, all signals of the closed-loop system are semi-globally uniformly ultimately bounded. Finally, simulation results including double pendulums system and two inverted pendulums on carts system are shown to demonstrate the performance and effectiveness of our approach.     

基于PSO和BP复合算法的模糊神经网络控制器

为了克服单独应用粒子群算法（PSO）或BP算法训练模糊神经网络控制器参数时存在的缺陷,提出了一种训练模糊神经网络参数的PSO＋BP算法。该算法将二者相结合,即在PSO算法中加入一个BP算子,以充分利用PSO算法的全局寻优能力和BP算法的局部搜索能力,从而更有效地提高其收敛速度、训练效率和提高该模糊神经网络控制器的控制效果。最后的仿真实验结果验证了该基于PSO＋BP复合算法的模糊神经网络控制器的有效性和可行性。     

一种回归神经网络的快速在线学习算法

针对回归神经网络BP学习算法收敛慢的缺陷,提出了一种新的快速在线递推学习算法.本算法在目标函数中引入了遗忘因子,并借助于非线性系统的最大似然估计原理成功地解决了动态非线性系统回归神经网络模型权系数学习的实时性和快速性问题.仿真结果表明,该算法比传统的回归BP学习算法具有更快的收敛速度.     

一种优化多层前向网络的IA-BP混合算法

该文针对免疫算法(IA)在优化较大规模的多层前向神经网络时收敛速度慢的缺点,给出了一种综合免疫算法和BP算法优点的IA-BP混合算法,它首先采用免疫算法进行全局搜索,然后调用BP算法进行局部搜索,从而加快收敛速度。实验结果表明该算法在训练较大规模的前向神经网络时性能要优于免疫算法和BP算法。     

模糊逻辑系统的GA+BP混合学习算法

提出一种在GA中融入BP算法的混合学习算法以实现模糊逻辑系统的自学习,利用遗传算法的全局最优性在大范围内搜索可能的极值,而用BP算法的误差梯度下降特性在极值点附近的快速搜索,从而达到了全局最优与快速搜索的有机结合,仿真结果表明,这种混合算法的学习效率无论是相对于GA还是BP均有显著提高。     

文化基因算法优化PID神经网络系统辨识

PID神经网络(PIDNN)是一种融合比例、微分、积分环节,结构简单固定,且具备动态网络特点的神经网络模型,适合于非线性系统辨识。但是网络对初始权值和样本质量敏感,参数难以选定,导致网络收敛速度慢,容易陷入局部极小。提出一种采用文化基因算法(Memetic Algorithm)优化网络权值的方法。在差分进化(DE)算法全局寻优结果基础上,通过混沌局部搜索算法,进一步优化网络权值;根据PIDNN特性,在优化过程中加入先验知识,采用L1正则项,对目标函数正则化,避免算法搜索到无潜力解,保证网络模型泛化能力。对一杂非线性系统进行辨识仿真,仿真结果表明优化后的神经网络辨识精度高,有良好的泛化能力。     

基于遗传神经网络的车辆导航路径规划

研究使用混合 GA-BP 神经网络算法来解决交通路径规划中的非线性问题。反向传播(Back-Propagation, BP)神经网络虽然能够很好地解决非线性问题,但它存在着容易陷入局部极小的不足,而遗传算法(Genetic Algorithm, GA)具有很强的宏观搜索能力和良好的全局优化性能,可以弥补BP的不足。用A*算法快速粗算出的几条可选路径作为 GA 的初始种群,然后用混合的 GA-BP 神经网络算法进行路径规划精算。仿真结果显示混合GA-BP神经网络算法在寻找路径规划的全局最优解上具有一定的优势。     

基于混合遗传算法求解非线性方程组

将非线性方程组的求解问题转化为函数优化问题,且综合考虑了拟牛顿法和遗传算法各自的优点,提出了一种用于求解非线性方程组的混合遗传算法。该混合算法充分发挥了拟牛顿法的局部搜索、收敛速度快和遗传算法的群体搜索、全局收敛的优点。为了证明该混合遗传算法的有效性,选择了几个典型的非线性方程组,从实验计算结果、收敛可靠性指标对比不同算法进行分析。数值模拟实验表明,该混合遗传算法具有很高的精确性和收敛性,是求解非线性方程组的一种有效算法。     

自适应差分进化算法优化BP神经网络的时间序列预测

针对BP神经网络学习算法随机初始化连接权值和阈值易使模型陷入局部极小点的缺点,设计了一种自适应差分进化算法优化BP神经网络的混合算法。该混合算法中,差分进化算法采用自适应变异和交叉因子优化BP神经网络的初始权值和阈值,再用预寻优得到的初始权值和阈值训练BP神经网络得到最优的权值和阈值。首先对改进的自适应差分进化算法运用测试函数进行性能测试,然后用一个经典时间序列问题对提出的混合算法进行了检验,并与一般的神经网络、ARIMA预测模型及其它混合预测模型进行了对比,实验结果表明,本文提出的混合算法有效并且明显提高了预测精度。     

非线性系统模糊神经网络变结构自适应控制

在非线性系统的模糊动力学模型基础上,提出一种模糊神经网络变结构自适应控制器;网络的结构根据非线性系统特性动态构成,基于该网络提出非线性预测器,基于梯度法提出了一种网络参数学习算法,并分析了收敛性及其性质。将网络预测器与参数学习算法相结合,构成自适应控制算法,证明了算法的收敛性。仿真结果证实了算法的有效性。     

A new hybrid method using evolutionary algorithms to train Fuzzy Cognitive Maps

A novel hybrid method based on evolutionary computation techniques is presented in this paper for training Fuzzy Cognitive Maps. Fuzzy Cognitive Maps is a soft computing technique for modeling complex systems, which combines the synergistic theories of neural networks and fuzzy logic. The methodology of developing Fuzzy Cognitive Maps relies on human expert experience and knowledge, but still exhibits weaknesses in utilization of learning methods and algorithmic background. For this purpose, we investigate a coupling of differential evolution algorithm and unsupervised Hebbian learning algorithm, using both the global search capabilities of Evolutionary strategies and the effectiveness of the nonlinear Hebbian learning rule. The use of differential evolution algorithm is related to the concept of evolution of a number of individuals from generation to generation and that of nonlinear Hebbian rule to the concept of adaptation to the environment by learning. The hybrid algorithm is introduced, presented and applied successfully in real-world problems, from chemical industry and medicine. Experimental results suggest that the hybrid strategy is capable to train FCM effectively leading the system to desired states and determining an appropriate weight matrix for each specific problem.     

A neuro-fuzzy system modeling with self-constructing rule generationand hybrid SVD-based learning

We propose an approach for neuro-fuzzy system modeling. A neuro-fuzzy system for a given set of input-output data is obtained in two steps. First, the data set is partitioned automatically into a set of clusters based on input-similarity and output-similarity tests. Membership functions associated with each cluster are defined according to statistical means and variances of the data points included in the cluster. Then, a fuzzy IF-THEN rule is extracted from each cluster to form a fuzzy rule-base. Second, a fuzzy neural network is constructed accordingly and parameters are refined to increase the precision of the fuzzy rule-base. To decrease the size of the search space and to speed up the convergence, we develop a hybrid learning algorithm which combines a recursive singular value decomposition-based least squares estimator and the gradient descent method. The proposed approach has advantages of determining the number of rules automatically and matching membership functions closely with the real distribution of the training data points. Besides, it learns faster, consumes less memory, and produces lower approximation errors than other methods.     

Fuzzy wavelet neural network based on fuzzy clustering and gradient techniques for time series prediction

This paper presents the development of fuzzy wavelet neural network system for time series prediction that combines the advantages of fuzzy systems and wavelet neural network. The structure of fuzzy wavelet neural network (FWNN) is proposed, and its learning algorithm is derived. The proposed network is constructed on the base of a set of TSK fuzzy rules that includes a wavelet function in the consequent part of each rule. A fuzzy c-means clustering algorithm is implemented to generate the rules, that is the structure of FWNN prediction model, automatically, and the gradient-learning algorithm is used for parameter identification. The use of fuzzy c-means clustering algorithm with the gradient algorithm allows to improve convergence of learning algorithm. FWNN is used for modeling and prediction of complex time series and prediction of foreign-exchange rates. Exchange rates are dynamic process that changes every day and have high-order nonlinearity. The statistical data for the last 2 years are used for the development of FWNN prediction model. Effectiveness of the proposed system is evaluated with the results obtained from the simulation of FWNN-based systems and with the comparative simulation results of previous related models.     

A novel compensation-based recurrent fuzzy neural network and its learning algorithm

Based on detailed study on several kinds of fuzzy neural networks, we propose a novel compensation-based recurrent fuzzy neural network (CRFNN) by adding recurrent element and compensatory element to the conventional fuzzy neural network. Then, we propose a sequential learning method for the structure identification of the CRFNN in order to confirm the fuzzy rules and their correlative parameters effectively. Furthermore, we improve the BP algorithm based on the characteristics of the proposed CRFNN to train the network. By modeling the typical nonlinear systems, we draw the conclusion that the proposed CRFNN has excellent dynamic response and strong learning ability. Supported by the National High-Tech Research and Development Program of China (Grant No. 2006AA05A107) and Special Fund of Jiangsu Province for Technology Transfer (Grant No. BA2007008)     

嵌入单纯形法的混合类电磁机制算法

针对类电磁机制算法存在局部搜索能力差的问题,提出一种基于单纯形法的混合类电磁机制算法。该混合算法首先利用反向学习策略构造初始种群以保证粒子均匀分布在搜索空间中。利用单纯形法对最优粒子进行局部搜索,增强了算法在最优点附近的局部搜索能力,以加快算法的收敛速度。四个基准测试函数的仿真实验结果表明,该算法具有更好的寻优性能。     

PSO优化算法飞机操纵面故障辨识研究

针对飞机复杂的非线性操纵面故障系统,建立故障模型,提取各种故障数据,并将粒子群优化算法应用于BP网络系统,提出了一种基于粒子群优化神经网络的故障诊断方法;该方法分阶段实施神经网络的训练,有效地加强了算法的全局搜索能力,采用PSO算法优化了传播中的权值和阈值,弥补了BP算法收敛速度慢和易陷入局部极小点的不足,提高了故障模式识别的能力;实验结果表明该方法加快了神经网络的学习收敛速度,提高了故障模式的识别正确率,对飞机操纵面的各种典型故障都能有效加以辨识。     

求解非线性方程组的混合粒子群算法

结合Hooke-Jeeves和粒子群的优点,提出了一种混合粒子群算法,用于求解非线性方程组,以克服Hooke-Jeeves算法对初始值敏感和粒子群容易陷入局部极值而导致解的精度不够的缺陷。该算法充分发挥了粒子群强大的全局搜索能力和Hooke-Jeeves的局部精细搜索能力,数值实验结果表明：能够以满意的精度求出对未知数具有敏感性的非线性方程组的解,具有良好的鲁棒性和较快的收敛速度和较高的搜索精度。     

基于遗传算法的自学习模糊逻辑系统

利用遗传算法实现模糊逻辑系统的自学习,提出了遗传算法和模糊逻辑系统的结合方式,并针对模糊逻辑系统的特点,提出了初始种群的生成方法,较大地提高了遗传模糊逻辑系统的自学习性能。仿真结果表明,该系统对复杂的非线性系统具有较好的学习效果。