基于神经网络一类非线性系统自适应控制

对一类未知可控非线性仿射系统,假设其状态不完全可测。首先,利用动态回归神经网络建立其状态方程和输出方程,用Lyapunov理论证明了辩识误差∈L∞;然后,设计状态反馈控制器,使系统的输出跟踪参考输出,从理论证明了跟踪误差趋于零。最后,通过一个仿真实验验证了本方法的有效性。     

神经网络在质量矩导弹控制系统上的应用

以所建立的质量矩导弹数学模型为基础,通过对模型合理的简化,得到一个耦合的非线性动力学系统,由于存在参数的不确定性以及建模误差,考虑到质量矩导弹的鲁棒性要求,采用神经网络自适应控制器对系统进行补偿。通过李亚普诺夫稳定理论证明跟踪误差是指数收敛的,仿真结果验证了这种方法的有效性。     

Decentralized adaptive fuzzy control of time-delayed interconnected systems with unknown backlash-like hysteresis

The problem of decentralized adaptive fuzzy control for a class of time-delayed interconnected nonlinear systems with unknown backlash-like hystersis is discussed. On the basis of the principle of variable structure control （VSC） and by using the fuzzy systems with linear adjustable parameters that are used to approximate plant unknown functions, a novel decentralized adaptive fuzzy control strategy with a supervisory controller is developed. A general method, which is modeled the backlash-like hysteresis, is proposed and removes the assumption that the boundedness of disturbance, and the slope of the backlash-like hystersis are known constants. Furthermore, the interconnection term is supposed to be pth-order polynomial in time-delayed states. In addition, the plant dynamic uncertainty and modeling errors are adaptively compensated by adjusting the parameters and gains on-line for each subsystems. By theoretical analysis, it is shown that the closed-loop fuzzy control systems are globally stable, with tracking error converging to zero. Simulation results demonstrate the effectiveness of the approach.     

Robust adaptive neural network control with supervisory controller

The problem of direct adaptive neural network control for a class of uncertain nonlinear systems with unknown constant control gain is studied in this paper. Based on the supervisory control strategy and the approximation capability of multilayer neural networks (MNNs), a novel design scheme of direct adaptive neural network controller is proposed.The adaptive law of the adjustable parameter vector and the matrix of weights in the neural networks and the gain of sliding mode control term to adaptively compensate for the residual and the approximation error of MNNs is determined by using a Lyapunov method. The approach does not require the optimal approximation error to be square-integrable or the supremum of the optimal approximation error to be known. By theoretical analysis, the closed-loop control system is proven to be globally stable in the sense that all signals involved are bounded, with tracking error converging to zero.Simulation results demonstrate the effectiveness of the approach.     

神经网络自校正预测拥塞控制算法研究

传输速率、处理速度和节点缓存容量的饱和非线性特性、传输延迟的随机时变性、用户接入的随机性以及高优先级业务的突发性,使得网络中存在严重的不确定性,由此给异步传输模式(ATM)网络拥塞控制系统的分析与设计带来极大的困难。为此设计了鲁棒神经网络自校正拥塞控制算法。其优点在于:(1)最大限度地减小了测量误差和随机干扰的作用,有效地补偿了时变不确定非线性的影响;(2)保证了闭环系统的稳定性、收敛性和公平性,增强了系统对随机延迟等不确定性的鲁棒性。仿真分析进一步验证了该算法的有效性。     

Adaptive output-feedback control for MIMO nonlinear systems with time-varying delays using neural networks

An adaptive neural network output-feedback regulation approach is proposed for a class of multi-input-multi-output nonlinear time-varying delayed systems. Both the designed observer and controller are free from time delays. Different from the existing results, this paper need not the assumption that the upper bounding functions of time-delay terms are known, and only a neural network is employed to compensate for all the upper bounding functions of time-delay terms, so the designed controller procedure is more simplified. In addition, the resulting closed-loop system is proved to be semi-globally ultimately uniformly bounded, and the output regulation error converges to a small residual set around the origin. Two simulation examples are provided to verify the effectiveness of control scheme.     

Adaptive tracking controller using BP neural networks for a class of nonlinear systems

An BP neural-network-based adaptive control (NNAC) design method is described whose aim is to control a class of partially unknown nonlinear systems. Making use of the online identification of BP neural networks, the results of the identification could be used into the parameters of the controller. Not only the strong robustness with respect to uncertain dynamics and nonlinearities can be obtained, but also the output tracking error between the plant output and the desired reference output can asymptotically converge to zero by Lyapunov theory in the process of this design method.And a simulation example is also presented to evaluate the effectiveness of the design.     

Adaptive neural control for a class of uncertain stochastic nonlinear systems with dead-zone

The problem of adaptive stabilization is addressed for a class of uncertain stochastic nonlinear strict-feedback systems with both unknown dead-zone and unknown gain functions.By using the backstepping method and neural network(NN) parameterization,a novel adaptive neural control scheme which contains fewer learning parameters is developed to solve the stabilization problem of such systems.Meanwhile,stability analysis is presented to guarantee that all the error variables are semi-globally uniformly ultimately bounded with desired probability in a compact set.The effectiveness of the proposed design is illustrated by simulation results.     

非线性离散系统的直接自适应神经网络控制器

对于一类非仿射离散时间系统,提出了一种新的自适应神经网络控制器。首先推导与原系统等价的仿射形式模型,由仿射模型推导控制律。控制律中采用一个神经网络,与传统的基于反馈线性化的自适应神经网络设计方法中采用两个神经网络相比,计算量大大减少且避免了控制器奇异问题。神经网络权值根据系统输入输出信号进行更新,另外σ项的引入,取消了为保证参数收敛持续激励的条件。系统的稳定性通过Lyapunov方法进行了分析,仿真实例验证了控制器的有效性。     

基于神经网络的BTT导弹鲁棒动态逆设计

针对存在不确定性的BTT导弹系统,基于神经网络提出了一种鲁棒动态逆控制系统设计方法。首先应用双时标假设将BTT导弹动力学分离为快变状态动力学和慢变状态动力学。然后,在巧妙地利用导弹气动参数特性设计Lyapunov函数的基础上,对快变状态动力学和慢变状态动力学分别进行动态逆控制设计。设计中应用RBF神经网络来逼近系统中存在的不确定性,证明了闭环系统的所有信号均有界且指数收敛至系统原点的一个邻域。最后给出的BTT导弹非线性六自由度数字仿真结果验证了该算法的有效性。     

Decentralized direct adaptive neural network control for a class of interconnected systems

1 .INTRODUCTIONA number of interconnected systems found in theworld, such as electric power systems ,industrymanipulators and computer networks , are oftencomposed of a set of subsystems . A centralizedcontrol strategy for the requirement of a large a-mount of information exchange between the sub-systems . A decentralized control method, devel-oped based only on local measurements ,is oftenpreferable . At present ,there have been many re-search results for adaptive control of interconnec-…     

神经网络模糊非参数模型自适应控制及仿真

提出一种基于神经网络的模糊非参数模型自适应控制方案。该方案仅用受控系统的I/O数据来设计控制器,综合了模糊控制、神经网络与非参数模型学习自适应控制各自的优点。仿真表明该控制器对模型、环境具有较好的适应能力和较强的鲁棒性。     

一种非线性时变系统小波网络辨识算法

提出一种可对任意非线性时变系统进行辨识的新方法，即基于小波神经网络的带自校正移动窗的递推最小二乘算法，与现有的神经网络辨识算法不同，该算法是根据被估权值时变速度的快慢来自适应地调整移动窗的长度，以跟踪非线性时变系统的动态特性，文中推导了了算法，并将全局算法进一步推广成不含任何矩阵运算的局部算法以提高算法的实时性能，几个典型的系统辨识仿真实例显示出这种方法具有跟踪精度高和计算简便的良好性能。     

Traffic control based on dahlin algorithm and neural network prediction in TAM networks

The propagation delay in networks has a great adverse effect on rate-based traffic control. This paper proposes the composite control based on Dab lin algorithm feedback control and neural network feedforward predictive compensation online for ABR (available bit rate) communication in ATM (asynchronous transfer mode) networks, which can overcome the adverse effect caused by the delay on the control rapidity and stability better. The theoretical analysis and simulation research show that the scheme can make sources respond to the changes of network status rapidly, avoid the congestion effectively and utilize the bandwidth sufficiently. Compared with PID (proportional-integral-derivative) control, cell loss rate is much lower, link utilization rate is much higher, and required buffer capacity is much smaller.     

动态神经网络的非线性系统鲁棒辨识和状态观测

针对多变量仿射非线性系统辨识和状态估计问题。采用动态神经网络作为辨识器和观测器,从而将系统辨识和状态观测设计过程合二为一,给出了辨识和状态估计的系统设计方法及具体设计步骤。在考虑建模误差项影响的情况下,采用基于Lyapunov理论的权调节律确保权值估计误差和状态观测误差的一致最终有界。仿真结果验证了所提方法的有效性。     

神经网络结构的递归T—S模型模型

提出一种新的递归T－S模型（Takagi-Sugeno模型）的模糊神经网络结构（TSFRNN）,利用动态BP（DBP）算法来学习训练神经网络的参数,通过与通常的多层前馈神经网络结构的T－S模糊神经网络（TSFNN）的对比仿真实验,说明在非线性系统建模方面TSFRNN比TSFNN更加优越。     

Adaptive integral dynamic surface control based on fully tuned radial basis function neural network

An adaptive integral dynamic surface control approach based on fully tuned radial basis function neural network (FTRBFNN) is presented for a general class of strict-feedback nonlinear systems, which may possess a wide class of uncertainties that are not linearly parameterized and do not have any prior knowledge of the bounding functions. FTRBFNN is employed to approximate the uncertainty online, and a systematic framework for adaptive controller design is given by dynamic surface control. The control algorithm has two outstanding features, namely, the neural network regulates the weights, width and center of Gaussian function simultaneously, which ensures the control system has perfect ability of restraining different unknown uncertainties and the integral term of tracking error introduced in the control law can eliminate the static error of the closed loop system effectively. As a result, high control precision can be achieved. All signals in the closed loop system can be guaranteed bounded by Lyapunov approach. Finally, simulation results demonstrate the validity of the control approach.     

新型神经网络模型参考自适应控制系统设计

针对任意复杂非线性系统，即控制器具有不可分离结构的离散非线性系统，提出新型神经网络模型参考自适应控制。该方案的提出简化了基于神经网络的模型参考自适应控制系统的设计，只需一个神经网络辨识器。统一了任意神经网络模型参考自适应控制的设计方法，更接近于工程实际。仿真结果证明了该方案的合理性和有效性。     

一类纯反馈非仿射非线性系统的自适应神经网络变结构控制

研究了一类非仿射的纯反馈单输入单输出非线性系统。针对此系统,在中值定理、神经网络参数化和解耦Backstepping的基础上,提出了一种自适应变结构神经网络控制策略,而且所给出的定理证明闭环系统的所有信号在平衡点上是半全局一致有界的。通过对一个非仿射CSTR对象的仿真验证了该方法的有效性。     

基于主元分析的RBF神经网络多模型切换控制

针对传统多模型自适应控制中子模型数量过多、学习和自适应能力的局限性等问题,将神经网络的学习能力和非线性逼近能力与多模型切换的思想相结合,提出基于主元分析的径向基(RBF)神经网络多模型切换控制算法。首先,基于主元分析法进行工况区域识别。其次,在不同的工况区域内采用RBF神经网络建立多个子模型并设计相应的控制器。最后,根据性能指标函数选择相应的控制器以得到最佳的控制效果。仿真结果表明,该算法大大减少了子模型数量,并改善了系统的动态性能。