Identification and Adaptive Control of Dynamic Nonlinear Systems Using Sigmoid Diagonal Recurrent Neural Network

The goal of this paper is to introduce a new neural network architecture called Sigmoid Diagonal Recurrent Neural Network (SDRNN) to be used in the adaptive control of nonlinear dynamical systems. This is done by adding a sigmoid weight victor in the hidden layer neurons to adapt of the shape of the sigmoid function making their outputs not restricted to the sigmoid function output. Also, we introduce a dynamic back propagation learning algorithm to train the new proposed network parameters. The simulation results showed that the (SDRNN) is more efficient and accurate than the DRNN in both the identification and adaptive control of nonlinear dynamical systems.

Lyapunov-Based Dynamic Neural Network for Adaptive Control of Complex Systems

In this paper, an adaptive neuro-control structure for complex dynamic system is proposed. A recurrent Neural Network is trained-off-line to learn the inverse dynamics of the system from the observation of the input-output data. The direct adaptive approach is performed after the training process is achieved. A lyapunov-Base training algorithm is proposed and used to adjust on-line the network weights so that the neural model output follows the desired one. The simulation results obtained verify the effectiveness of the proposed control method.

A Fuzzy-Neural Network Control of Nonlinear Dynamic Systems

In this paper, an adaptive dynamic control scheme based on a fuzzy neural network is presented, that presents utilizes both feed-forward and feedback controller elements. The former of the two elements comprises a neural network with both identification and control role, and the latter is a fuzzy neural algorithm, which is introduced to provide additional control enhancement. The feedforward controller provides only coarse control, whereas the feedback controller can generate on-line conditional proposition rule automatically to improve the overall control action. These properties make the design very versatile and applicable to a range of industrial applications.

Two-Phase Rate Adaptation Strategy for Improving Real-Time Video QoE in Mobile Networks

With the popularity of smart handheld devices, mobile streaming video has multiplied the global network traffic in recent years. A huge concern of users' quality of experience(Qo E) has made rate adaptation methods very attractive. In this paper, we propose a two-phase rate adaptation strategy to improve users' real-time video Qo E. First, to measure and assess video Qo E, we provide a continuous Qo E prediction engine modeled by RNN recurrent neural network. Different from traditional Qo E models which consider the Qo E-aware factors separately or incompletely, our RNN-Qo E model accounts for three descriptive factors(video quality, rebuffering, and rate change) and reflects the impact of cognitive memory and recency. Besides, the video playing is separated into the initial startup phase and the steady playback phase, and we takes different optimization goals for each phase: the former aims at shortening the startup delay while the latter ameliorates the video quality and the rebufferings. Simulation results have shown that RNN-Qo E can follow the subjective Qo E quite well, and the proposed strategy can effectively reduce the occurrence of rebufferings caused by the mismatch between the requested video rates and the fluctuated throughput and attains standout performance on real-time Qo E compared with classical rate adaption methods.

Wastewater treatment control method based on a rule adaptive recurrent fuzzy neural network

Purpose-The purpose of this paper is to present an on-line modeling and controlling scheme based on the dynamic recurrent neural network for wastewater treatment system.Design/methodology/approach-A control strategy based on rule adaptive recurrent neural network(RARFNN)is proposed in this paper to control the dissolved oxygen(DO)concentration and nitrate nitrogen(SNo)concentration.The structure of the RARFNN is self-organized by a rule adaptive algorithm,and the rule adaptive algorithm considers the overall information processing ability of neural network.Furthermore,a stability analysis method is given to prove the convergence of the proposed RARFNN.Findings-By application in the control problem of wastewater treatment process(WWTP),results show that the proposed control method achieves better performance compared to other methods.Originality/value-The proposed on-line modeling and controlling method uses the RARFNN to model and control the dynamic WWTP.The RARFNN can adjust its structure and parameters according to the changes of biochemical reactions and pollutant concentrations.And,the rule adaptive mechanism considers the overall information processing ability judgment of the neural network,which can ensure that the neural network contains the information of the biochemical reactions.

Compensation for secondary uncertainty in electro-hydraulic servo system by gain adaptive sliding mode variable structure control

Based on consideration of the differential relations between the immeasurable variables and measurable variables in electro-hydraulic servo system,adaptive dynamic recurrent fuzzy neural networks(ADRFNNs) were employed to identify the primary uncertainty and the mathematic model of the system was turned into an equivalent linear model with terms of secondary uncertainty.At the same time,gain adaptive sliding mode variable structure control(GASMVSC) was employed to synthesize the control effort.The results show that the unrealization problem caused by some system's immeasurable state variables in traditional fuzzy neural networks(TFNN) taking all state variables as its inputs is overcome.On the other hand,the identification by the ADRFNNs online with high accuracy and the adaptive function of the correction term's gain in the GASMVSC make the system possess strong robustness and improved steady accuracy,and the chattering phenomenon of the control effort is also suppressed effectively.

Adaptive inverse control of air supply flow for proton exchange membrane fuel cell systems

To prevent the oxygen starvation and improve the system output performance, an adaptive inverse control （AIC） strategy is developed to regulate the air supply flow of a proton exchange membrane fuel cell （PEMFC） system in this paper. The PEMFC stack and the air supply system including a compressor and a supply manifold are modeled for the purpose of performance analysis and controller design. A recurrent fuzzy neural network （RFNN） is utilized to identify the inverse model of the controlled system and generates a suitable control input during the abrupt step change of external disturbances. Compared with the PI controller, numerical simulations are performed to validate the effectiveness and advantages of the proposed AIC strategy.

AN INTELLIGENT CONTROL SYSTEM BASED ON RECURRENT NEURAL FUZZY NETWORK AND ITS APPLICATION TO CSTR

In this paper, an intelligent control system based on recurrent neural fuzzynetwork is presented for complex, uncertain and nonlinear processes, in which a recurrent neuralfuzzy network is used as controller (RNFNC) to control a process adaptively and a recurrent neuralnetwork based on recursive predictive error algorithm (RNNM) is utilized to estimate the gradientinformation partial deriv y/partial deriv u for optimizing the parameters of controller. Comparedwith many neural fuzzy control systems, it uses recurrent neural network to realize the fuzzycontroller. Moreover, recursive predictive error algorithm (RPE) is implemented to construct RNNM online. Lastly, in order to evaluate the performance of the proposed control system, the presentedcontrol system is applied to continuously stirre'd tank reactor (CSTR). Simulation comparisons,based on control effect and output error, with general fuzzy controller and feed-forward neuralfuzzy network controller (FNFNC), are conducted. In addition, the rates of convergence of RNNMrespectively using RPE algorithm and gradient learning algorithm are also compared. The results showthat the proposed control system is better for controlling uncertain and nonlinear processes.

A Fuzzy Neural Network Based Dynamic Data Allocation Model on Heterogeneous Multi-GPUs for Large-scale Computations

The parallel computation capabilities of modern graphics processing units （GPUs） have attracted increasing attention from researchers and engineers who have been conducting high computational throughput studies. However, current single GPU based engineering solutions are often struggling to fulfill their real-time requirements. Thus, the multi-GPU-based approach has become a popular and cost-effective choice for tackling the demands. In those cases, the computational load balancing over multiple GPU ＂nodes＂ is often the key and bottleneck that affect the quality and performance of the real=time system. The existing load balancing approaches are mainly based on the assumption that all GPU nodes in the same computer framework are of equal computational performance, which is often not the case due to cluster design and other legacy issues. This paper presents a novel dynamic load balancing （DLB） model for rapid data division and allocation on heterogeneous GPU nodes based on an innovative fuzzy neural network （FNN）. In this research, a 5-state parameter feedback mechanism defining the overall cluster and node performance is proposed. The corresponding FNN-based DLB model will be capable of monitoring and predicting individual node performance under different workload scenarios. A real=time adaptive scheduler has been devised to reorganize the data inputs to each node when necessary to maintain their runtime computational performance. The devised model has been implemented on two dimensional （2D） discrete wavelet transform （DWT） applications for evaluation. Experiment results show that this DLB model enables a high computational throughput while ensuring real=time and precision requirements from complex computational tasks.

一种用于非线性动态辨识的新型神经网络

为提高非线性动态系统辨识(NDSI)的效果,在结合自建型模糊神经网络(SCFNN)和多层神经元神经网络(MLPNN)的基础上,提出一种自建递归型模糊神经网络(SCRFNN)。SCRFNN相较于前者,多了一个递归通道与抑制模糊规则产生机制;相较于后者,增加了模糊推论与一个递归通道。为验证SCRFNN在系统辨识中的有效性,设计一个新的NDSI在线学习模型与代码设计流程图,并以此作为在线学习架构,将以上3个神经网络模型对4个串-并型非线性动态系统进行辨识分析。经过仿真表明,新提出的SCRFNN通过存储内部状态,具备了映射动态特征的功能,从而使系统具有适应时变特性的能力,更适合于非线性动态系统的辩识。且在模糊规则数、学习收敛速度、学习与预测误差均方根值、预测精准度方面也取得了良好的效果。

基于模糊神经网络的工业数据流优先级适配机制

在传统的工业现场级网络中,存在大量具有不同时延需求的业务,如何满足不同业务的时延需求存在挑战。针对在工业场景中现场级网络应如何保障系统反馈控制实时性的问题,提出了一种基于模糊推理模型的优先级适配机制。该机制通过动态调整网络中数据流的优先级,以满足各类异构业务的传输需求,保证系统反馈控制的实时性;同时,为了使其能够与时间敏感网络的优先级结合,设计了离散量化输出模型,为实现确定性网络调度提供依据。最后通过仿真,验证了该机制的实时性与有效性。

一种递归模糊神经网络自适应控制方法

构造了一种递归模糊神经网络(RFNN),该RFNN利用递归神经网络实现模糊推理,并通过在网络的第一层添加了反馈连接,使网络具有了动态信息处理能力.基于所设计的RFNN,提出了一种自适应控制方案,在该控制方案中,采用了两个RFNN分别用于对被控对象进行辨识和控制.将所提出的自适应控制方案应用于交流伺服系统,并给出了仿真实验结果,验证了所提方法的有效性.

基于模糊神经网络的车辆间距智能自适应控制

为了实现汽车行驶过程中与前车车距的自动控制,提出了一种基于模糊神经网络的车辆纵向间距智能自适应控制方法.利用神经网络对车辆纵向运动进行辨识,将神经网络和模糊控制结合起来,设计模糊神经网络加速度控制器,利用神经网络的学习功能修正控制器的隶属度函数的参数和控制规则.仿真表明系统响应快,控制精度高,和传统方法相比具有较强的抗干扰能力和自适应性.

基于递归模糊神经网络的移动机器人滑模控制

针对非完整移动机器人轨迹跟踪控制问题,提出了一种Backstepping运动学控制器与自适应动态递归模糊神经滑模控制器相结合的控制结构。采用遗传算法对运动学控制器的参数进行了优化选取,有效地抑制了因初始位姿过大而引起的初始速度及输出力矩过大的问题;采用动态递归模糊神经网络(Adaptive dynamic recurrent fuzzy neural network,AD-RFNN)对动态非线性不确定部分进行在线估计,使不确定性估计误差大大减小;通过与自适应鲁棒控制器结合应用,不但解决了移动机器人的参数与非参数不确定性问题,同时也消除了在滑模控制中的输入抖振现象;基于Lyapunov方法的设计过程,保证了控制系统的稳定与收敛;仿真结果表明了该方法的有效性。

用于气动伺服系统的自适应神经模糊控制器

研究了一种基于压力比例阀的气动伺服系统自适应神经模糊控制器。其中的神经网络辨识器（NNI）通过离线训练可以充分逼近非线性动态系统的模型，并能够在线调整模糊控制器的控制规则。系统的位置控制精度和伺服特性有了很大改善。试验结果表明，所提出的控制器对该气动伺服系统具有很好的控制特性以及很强的自适应能力。

基于递归神经网络的伺服系统自适应反步控制

针对伺服系统的系统参数摄动和非线性动态摩擦补偿问题,提出基于递归神经网络(RNN)的自适应反步控制(RNABC)系统设计方法。RNABC系统由反步控制器和鲁棒控制器组成,反步控制器包含RNN不确定观测器,鲁棒控制器则用来消除由于引入不确定观测器而带来的逼近误差。由于自适应反步控制的自适应律源于Lyapunoy函数的,因此系统的稳定性得到了保证。仿真结果表明,对于系统参数摄动和非线性摩擦干扰RNABC能使伺服系统具有很好的跟踪性能。

基于动态递归模糊神经网络盲均衡算法的研究

模糊系统和神经网络已广泛应用于系统的辨识和控制,但是传统的模糊神经网络是一种静态映射,不适用于动态系统的辨识;而由于无线通信信道的时变性和不确定性,决定了盲均衡器本身就是一个动态的均衡过程,所以研究利用动态递归模糊神经网络的盲均衡算法是可行的,而且也是必要的。仿真结果表明:由于动态模糊神经网络的均衡过程同时利用了系统的当前数据和历史数据,对动态系统的均衡,较传统神经网络在均衡的精度和稳定性方面具有更好的效果。

一种自适应模糊小波神经网络及其在交流伺服控制中的应用

针对某武器大功率交流伺服系统所存在的大变负载、慢时变、强耦合的非线性特性和不确定扰动等问题,提出了模糊小波神经网络(FWNN)间接自适应控制器,该控制器的特点为Takagi-Sugeno-Kang(TSK)模糊模型的后件部分由自回归小波神经网络(SRWNN)构成。给出了SRWNN参数的迭代算法,利用SRWNN辨识器为控制器提供实时梯度信息,有效地克服了参数变化和负载扰动等不确定因素的影响,且具有良好的动态特性。采用Lyapunov稳定性理论方法证明了闭环系统的稳定性。仿真研究和样机试验结果证明了所提方案的有效性和正确性。

基于模糊神经网络的动态非线性系统辨识研究

针对静态模糊神经网络对动态系统辨识精度低的特点,在5层静态模糊神经网络基础上进行了优化和改进,形成了可将暂态信息记忆于网络的动态回归层的动态模糊神经网络,来提高对动态系统的辨识能力。同时给出了参数的动态自适应学习算法。通过仿真实验,证明提出的动态模糊神经网络对动态非线性系统的辨识,可以取得较好的辨识精度,较快的网络收敛速度,为动态非线性系统的辨识提供新的思路。

自组织递归区间二型模糊神经网络在动态时变系统辨识中的应用

针对动态时变系统辨识过程中存在噪声干扰的问题,本文将区间二型模糊集结合到递归神经网络中,提出了自组织递归区间二型模糊神经网络以增强动态时变系统的抗噪能力。该自组织递归区间二型模糊神经网络由前件和后件两部分构成:前件为区间二型模糊集模型,用于将每个规则的激活强度反馈到自身构成内反馈回路,其参数学习采用梯度下降算法;后件为带有区间权值的Takagi-Sugeno-Kang(TSK)模型,其参数学习采用有序规则卡尔曼滤波算法,且网络初始规则数为零。所有规则均通过结构学习和前后件参数同时在线学习来产生,其网络结构学习采用的是在线区间二型模糊群集。为验证提出的神经网络的优越性,将其应用到单输入单输出动态时变系统的辨识中。实验结果表明,相对于前馈一型/二型模糊神经网络、递归一型模糊神经网络,该神经网络的辨识能力强,即使在存在白噪声的条件下,也能减小测试及训练误差。