多变量自适应PID型神经网络控制器及其设计方法

提出一种PID型神经网络控制器（PID-like Neural Network Controller，PIDNNC）及其设计方法．基于PID的简单结构和良好性能优势以及神经网络的自调节和自适应的特长，创建一种具有PID结构的多变量自适应的PID型神经网络控制器．该网络控制器的隐含层由带有输出反馈和激活反馈的混合局部连接递归网络组成．通过定义误差函数作为设计目标，采用弹性BP算法，并用变化率以及弹性BP算法中的符号法来处理某些求导关系，获得适于实时在线调整网络权值的修正公式．根据李亚普诺夫稳定性定理推导出确保控制系统稳定的学习速率的取值范围．最后通过实例进一步说明所提出网络控制器的优越性．     

基于PID控制器的铝热连轧张力控制系统的设计与实现

针对PID控制器在铝热连轧张力控制系统中收敛速度慢的问题,提出一种自适应权值粒子群算法优化神经网络PID控制器的设计方法,该方法采用自适应权值粒子群算法优化神经网络的权值和阈值,使它们在调节PID控制器时找到最优参数,仿真结果表明,在铝热连轧张力控制系统中,自适应粒子群算法优化的神经网络PID控制器与其他PID控制器相比能更快地使张力达到稳定状态、缩短响应时间、改善板形。     

基于组合积分过程的自适应控制算法研究

组合积分系统广泛存在于钢铁、石油化工、食品加工、打叶复烤、矿物处理等现代工业生产过程中,传统将被控对象简单通过一阶Pade近似设计控制器的方法已无法满足更高精度的控制要求,且基于组合积分控制器的设计仍停留在非自适应控制的阶段。研究根据组合积分系统对象特性,利用带遗忘因子的递推最小二乘算法、相关性分析算法以及粒子群优化算法首次提出并设计了组合积分自适应控制器,并通过系统仿真验证了组合积分自适应控制算法的非线性在线跟踪能力、抗干扰特性以及鲁棒性,取得了理想的控制效果。组合积分自适应控制器的设计思想也可应用于其他低阶时滞系统的自适应控制过程中,只需将广义目标过程 按组合积分模型设计即可实现。因此,组合积分自适应控制器对于提高传统时滞系统自适应控制器的控制精度有着广泛的意义,并且在带有时滞环节的工业过程自适应控制研究中有极大的应用价值。     

神经网络自适应模糊控制在温度控制系统中的应用

把神经网络与模糊控制相结合，提出一种基于神经网络的自适应模糊控制器。这种控制器由模糊神经网络控制器和模型网络组成，采用快速的变斜率梯度下降算法学习，具有自适应学习功能，仿真结果及其应用于温度控制系统中，控制性能明显于一般Ｆｕｚｚｙ控制。     

基于PSD算法的单神经元PID控制器在汽温控制中的应用

介绍将自适应PSD控制算法中递推计算并修正增益的方法引入单神经元PID控制，形成了具有增益自适应能力的控制器，设计了基于ISD算法的单神经元PID控制器，并应用于超临界机组过热汽温控制系统。仿真结果表明，基于PSD算法的单神经元PID控制器具有较强的自适应能力和鲁棒性，其控制品质优于常规的PID控制器和一般单神经元控制器。     

基于混合粒子群算法的多变量解耦控制器优化

研究薄膜厚度系统控制器优化问题,由于神经网络初始权值难以确定,使PID神经网络对控制器参数的自适应、自学习能力变差,最终导致控制效果不理想.为了解决这一问题,提出一种混合的粒子群算法,用来优化神经网络初始权值,进而实现控制器的优化,并应用于薄膜厚度控制系统.仿真结果表明:与PID神经网络控制器相比,优化后的控制器更好的实现了多变量控制系统的解耦控制,提高了控制器参数的自适应自学习能力,控制效果明显,并且系统的鲁棒性较好.     

一种自适应模糊CMAC控制器

本文提出一种自适应模糊ＣＭＡＣ控制器的设计方法，该控制器由模糊ＣＭＡＣ神经网络的五层节点实现模糊控制的输入，模糊化，模糊逻辑运算，归一化及输出值准确化运算，并由合适的ＢＰ训练算法修改相应的权系数，实现模糊控制规则的调整。     

基于粒子群算法的PID神经网络解耦控制

基于粒子群的优化算法具有对整个参数空间进行高效并行搜索的特点以及PID神经网络的自调节和自适应特性,设计了具有PID结构的多变量自适应神经网络控制器。该算法采用粒子群算法优化PID神经网络初始权值,并将优化后的最优初始权值控制非线性耦合系统。系统仿真结果表明,粒子群优化后的PID神经网络控制器具有逼近控制目标更快、响应时间较短的显著优点。该控制策略可在大范围内克服系统的非线性和强耦合问题,具有一定的理论研究价值和工程实用价值。     

神经模糊控制在船舶自动舵中的应用

针对常规模糊自动舵由于受船舶控制过程的非线性、时变性以及风浪干扰等因素影响,模糊控制规则和隶属函数需要校正,利用神经网络的自学习能力,用神经网络去实现模糊控制,设计自动舵神经模糊控制器,采用BP算法和最小二乘算法的混合学习算法实现对模糊规则和隶属函数的参数训练,提高控制器的自适应能力.仿真实验表明所设计的控制器有效可行.适应船舶在风浪干扰环境下的控制性能要求.     

神经模糊控制在船舶自动舵中的应用

针对常规模糊自动舵由于受船舶控制过程的非线性、时变性以及风浪干扰等因素影响,模糊控制规则和隶属函数需要校正,利用神经网络的自学习能力,用神经网络去实现模糊控制,设计自动舵神经模糊控制器,采用BP算法和最小二乘算法的混合学习算法实现对模糊规则和隶属函数的参数训练,提高控制器的自适应能力。仿真实验表明所设计的控制器有效可行,适应船舶在风浪干扰环境下的控制性能要求。     

基于复合正交神经网络的灰色PID控制

结合传统反馈控制方法和灰色预测控制的预测控制器已在控制系统中获得了成功的应用。由于复合正交神经网络具有学习算法简单、收敛速度快,有逼近线性或非线性函数的优良特性。与灰色预测方法相比,神经网络预测精度高,且误差可控,如果把神经网络作为灰色预测器,建立一种灰色预测控制,那么就会在控制系统中获得良好的控制性能。为此,提出一种结合传统的PID控制和神经网络灰色预测补偿的灰色PID控制器,可对系统进行在线灰色估计和控制,由复合正交神经网络对不确定部分建立的灰色预测模型,可根据系统的参数变化来自动调节预测补偿值,使系统响应具有适应性。仿真结果表明,与传统的PID控制方法相比,该控制器可获得更为优良的动态性能和鲁棒性。     

基于HGA的模糊神经控制器设计及其应用

将神经网络与模糊控制相结合,实现了模糊控制器的自学习和自适应。给出一种基于递阶遗传算法的模糊神经网络优化算法,通过对每个染色体采用递阶编码,可以同时优化模糊神经网络结构和权值参数。将这种模糊神经网络控制器应用于镍氢电池的充电控制中,证明了算法的有效性。     

倒立摆系统的高精度控制器设计与实现

对线性二次调节器LQR算法中Q和R矩阵的参数与控制系统反馈矩阵Ⅸ之间的关系进行了实验研究,并将所获得的最佳反馈矩阵作为所设计的神经网络控制器的权值初始值。该神经网络控制器是带有局部递归神经网络并具有PID结构的控制器,因而设计简单,尤其适合用于多变量非线性时变系统。通过对一级和二级直线倒立摆系统的具体控制器的设计以及实验,将LQR控制器与神经网络控制器分别在无干扰和有干扰情况下的控制效果进行了对比分析,设计并实现了具有控制精度以及鲁棒性比最优线性二次调节器更高的一级和二级直线倒立摆系统。     

Adaptive recurrent neural network control using a structure adaptation algorithm

This paper proposes an adaptive recurrent neural network control (ARNNC) system with structure adaptation algorithm for the uncertain nonlinear systems. The developed ARNNC system is composed of a neural controller and a robust controller. The neural controller which uses a self-structuring recurrent neural network (SRNN) is the principal controller, and the robust controller is designed to achieve L ² tracking performance with desired attenuation level. The SRNN approximator is used to online estimate an ideal tracking controller with the online structuring and parameter learning algorithms. The structure learning possesses the ability of both adding and pruning hidden neurons, and the parameter learning adjusts the interconnection weights of neural network to achieve favorable approximation performance. And, by the L ² control design technique, the worst effect of approximation error on the tracking error can be attenuated to be less or equal to a specified level. Finally, the proposed ARNNC system with structure adaptation algorithm is applied to control two nonlinear dynamic systems. Simulation results prove that the proposed ARNNC system with structure adaptation algorithm can achieve favorable tracking performance even unknown the control system dynamics function.     

Learning soft computing control strategies in a modular neural network architecture

Modelling and control of nonlinear dynamical systems is a challenging problem since the dynamics of such systems change over their parameter space. Conventional methodologies for designing nonlinear control laws, such as gain scheduling, are effective because the designer partitions the overall complex control into a number of simpler sub-tasks. This paper describes a new genetic algorithm based method for the design of a modular neural network (MNN) control architecture that learns such partitions of an overall complex control task. Here a chromosome represents both the structure and parameters of an individual neural network in the MNN controller and a hierarchical fuzzy approach is used to select the chromosomes required to accomplish a given control task. This new strategy is applied to the end-point tracking of a single-link flexible manipulator modelled from experimental data. Results show that the MNN controller is simple to design and produces superior performance compared to a single neural network (SNN) controller which is theoretically capable of achieving the desired trajectory.     

基于模糊神经网络PID控制器的EEC数字化设计

为实现航空发动机模拟式电子控制器(EEC)的数字化设计,以其低压压气机导流叶片调节通道为主要研究对象,提出一种模糊神经网络PID控制器,将模糊控制、神经网络、PID控制相结合,利用模糊控制专家经验优势和神经网络的自学习、自适应能力,优化PID控制参数,实现控制性能提升。仿真结果显示,基于模糊神经网络的PID控制器控制性能有较大提高,具有比常规神经网络PID控制器更小的超调量和更好的抗干扰性;适用于定常系统和非定常系统,具有更好的自适应性与鲁棒性;可应用于航空发动机模拟式电子控制器(EEC)的数字化设计。     

FPGA‐based adaptive dynamic sliding‐mode neural control for a brushless DC motor

In the adaptive neural control design, since the number of hidden neurons is finite for real‐time applications, the approximation errors introduced by the neural network cannot be inevitable. To ensure the stability of the adaptive neural control system, a switching compensator is designed to dispel the approximation error. However, it will lead to substantial chattering in the control effort. In this paper, an adaptive dynamic sliding‐mode neural control (ADSNC) system composed of a neural controller and a fuzzy compensator is proposed to tackle this problem. The neural controller, using a radial basis function neural network, is the main controller and the fuzzy compensator is designed to eliminate the approximation error introduced by the neural controller. Moreover, a proportional‐integral‐type adaptation learning algorithm is developed based on the Lyapunov function; thus not only the system stability can be guaranteed but also the convergence of the tracking error and controller parameters can speed up. Finally, the proposed ADSNC system is implemented based on a field programmable gate array chip for low‐cost and high‐performance industrial applications and is applied to control a brushless DC (BLDC) motor to show its effectiveness. The experimental results demonstrate the proposed ADSNC scheme can achieve favorable control performance without encountering chattering phenomena. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

Application of neural networks to temperature control in thermal power plants

In a thermal power plant with once-through boilers, it is important to control the temperature at the middle point where water becomes steam. However, there are many problems in the design of such a control system, due to a long system response delay, dead-zone and saturation of the actuator mechanisms, uncertainties in the system model and/or parameters, and process noise. To overcome these problems, an adaptive controller has been designed using neural networks, and tested extensively via simulations.

One of the key problems in designing such a controller is to develop an efficient training algorithm. Neural networks are usually trained using the output errors of the network, instead of using the output errors of the controlled plant. However, when a neural network is used to control a plant directly, the output errors of the network are unknown, since the desired control actions are unknown. This paper proposes a simple training algorithm for a class of nonlinear systems, which enables the neural network to be trained with the output errors of the controlled plant. The only a priori knowledge of the controlled plant is the direction of its output response. Due to its simple structure and algorithm, and good performance, the proposed controller has high potential for handling difficult problems in process-control systems.     

Genetic algorithm design of neural network and fuzzy logic controllers

This paper discusses the design of neural network and fuzzy logic controllers using genetic algorithms, for real-time control of flows in sewerage networks. The soft controllers operate in a critical control range, with a simple set-point strategy governing “easy” cases. The genetic algorithm designs controllers and set-points by repeated application of a simulator. A comparison between neural network, fuzzy logic and benchmark controller performance is presented. Global and local control strategies are compared. Methods to reduce execution time of the genetic algorithm, including the use of a Tabu algorithm for training data selection, are also discussed. The results indicate that local control is superior to global control, and that the genetic algorithm design of soft controllers is feasible even for complex flow systems of a realistic scale. Neural network and fuzzy logic controllers have comparable performance, although neural networks can be successfully optimised more consistently.     

基于DNA-GA-RBF的PID参数优化

PID控制器因为结构简单,容易实现,并且具有较强的鲁棒性,因而被广泛应用于各种工业过程控制中。控制器参数直接影响控制器的性能,因此控制器的设计主要体现在控制器参数的调整上。参数自整定技术的发展一方面减轻了控制工程师现场调试的工作量,节省了大量的时间,另一方面也使整定的结果更加理想。利用DNA遗传算法的全局搜索的功能特性,对整个RBF神经网络参数进行优化,将RBF网络不同的中心矢量和其对应的基宽向量及各个调节权重统一编码,使得整个网络模型达到全局最优。然后利用该混合算法对PID参数进行整定,仿真证明该算法能有效地实现PID参数最优整定,其性能优于常规的RBF算法,为解决PID控制器参数最优设计提供了一种有效的方法。