共查询到20条相似文献,搜索用时 203 毫秒
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基于Adalines的模型跟踪自适应控制 总被引:1,自引:0,他引:1
本文根据双层Adalines逼近任意非线性函数的特性构造神经网络控制器,并采用一参考模型的输出与实际被控系统的输出之差对该神经网络控制器进行BP算法学习训练。从而在保证控制系统稳态性能的同时提高了控制系统的动态响应性能。最后把此基于Adalines的模型跟踪自适应控制策略用于车削系统并进行了仿真实验。 相似文献
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基于动态递归神经网络的自适应PID控制 总被引:1,自引:1,他引:0
提出一种基于动态递归神经网络的自适应PID控制方案,该控制系统由神经网络辨识器和神经网络控制器组成。辨识器采用单隐层的动态递归神经网络,网络结构为2-4-1;辨识算法为动态BP算法;控制器采用两层线性结构的神经网络,输入为系统偏差及其一阶、二阶微分,因此具有增量型PID控制结构。应用该控制系统对一非线性时变系统进行仿真研究,仿真结果表明该控制方案不仅具有良好的跟踪特性,而且对系统参数变化具有较强的鲁棒性。 相似文献
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针对一类温度控制系统中存在的非线性和参数不确定等问题,提出一种复合神经网络自适应控制结构.在控制系统中构造了神经网络正模型来再现被控对象的动态特性,用神经网络控制器实现优化控制律的非线性映射.文中选用了被控对象80组历史数据作为样本集,并利用遗传算法的全局搜索能力及高效率来训练多层前向神经网络的权系数.最后用升降温工艺曲线作为输入对温度控制系统进行仿真.仿真结果表明,应用遗传算法能够提高神经网络的学习效率.保证神经网络全局快速收敛,从而克服了传统的误差反传学习算法的一些缺点.证明了采用这种神经网络自适应控制结构.使神经网络控制器的输出可以适应对象参数和环境的变化.使温度控制系统具有很好的学习和自适应控制能力,取得了良好的控制效果. 相似文献
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提出了一种基于遗传算法和神经网络的自适应PID控制器的设计方法。该控制器主要由三个部分组成:利用遗传算法优化PID参数,和RBF神经网络结合,对被控对象逼近,搜索出一组准优的初始参数;RBF神经网络完成对被控对象Jacobian信息辨识;基于单神经元的自适应PID控制器,在线调整PID参数,以确保系统的响应具有最优的动态和稳态性能。仿真结果表明,控制器具有响应速度快,稳态精度高等特点,可用于控制不同的对象和过程。 相似文献
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提出了一种基于遗传算法的DRNN神经网络辨识方法。该方法是针对动态BP算法训练神经网络时收敛速度慢、动态特性不够理想等不足,用遗传算法来优化神经网络辨识器的参数,以提高辨识系统的性能。仿真实验表明该辨识方法对于动态非线系统具有很好辨识精度。 相似文献
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基于模糊神经网络的模型参考自适应控制 总被引:11,自引:0,他引:11
用模糊神经网络作为控制器,依靠参考模型产生理想的控制系统闭环响应,从而随时得
到控制系统的输出误差.用梯度法实时修正模糊控制器的输入和输出隶属度参数,得到一种
在线模糊自适应控制的新方法.通过倒立摆的仿真实验表明,该方法是可行的并能适应对象
特性的大范围变化. 相似文献
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讨论了充液航天器大角度姿态机动自适应非线性动态逆控制设计.推导了航天器-液体晃动耦合系统动力学方程.采用单摆等效力学模型对液体燃料晃动进行动力学建模.由于充液航天器控制系统的强耦合非线性,故采用神经网络构造系统的自适应非线性动态逆控制器.通过实际算例对该控制器的跟综性能进行了测试,结果证明该自适应非线性动态逆控制器在包... 相似文献
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基于复合正交神经网络的自适应逆控制系统 总被引:10,自引:0,他引:10
目前,在自适应逆控制系统中常采用BP神经网络,而BP网络存在算法复杂、易陷入局部极小解等不足。而正交神经网络能克服BP网络的不足,但由于正交神经网络学习算法存在某些局限性,提出了一种复合正交神经网络,该正交网络结构与三层前向正交网络相同,不同的是正交网络的隐单元处理函数采用带参数的Sigmoid函数的复合正交函数,该神经网络算法简单,学习收敛速度快,并能对网络的函数参数进行优化,为非线性系统的动态建模提供了一种方法。仿真实验表明,网络在用于过程的自适应逆控制中具有很高的控制精度和自适应学习能力。该动态神经网络比其它神经网络具有更强的建模能力与学习适应性,有线性、非线性逼近精度高等优异特性,非常适合于实时控制系统。 相似文献
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针对一类未知对象参数的控制问题,设计了一种基于神经网络补偿的特征模型控制方法.利用特征建模思想建立对象的时变差分方程,并在黄金分割自适应控制律的基础上,通过引入一个神经网络监督控制器,对特征模型在动态建模过程中的产生的误差起到前馈补偿作用,进一步改善了系统的动态控制性能;同时在系统受到外扰情况下,利用黄金分割控制律的反... 相似文献
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Welding is an efficient reliable metal joining process in which the coalescence of metals is achieved by fusion. Localized heating during welding, followed by rapid cooling, induce residual stresses in the weld and in the base metal. Determination of magnitude and distribution of welding residual stresses is essential and important. Data sets from finite element method (FEM) model are used to train the developed neural network model trained with genetic algorithm and particle swarm optimization (NN–GA–PSO model). The performance of the developed NN–GA–PSO model is compared neural network model trained with genetic algorithm (NN–GA) and neural network model trained with particle swarm optimization (NN–PSO) model. Among the developed models, performance of NN–GA–PSO model is superior in terms of computational speed and accuracy. Confirmatory experiments are performed using X-ray diffraction method to confirm the accuracy of the developed models. These developed models can be used to set the initial weld process parameters in shop floor welding environment. 相似文献
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In this paper, a cerebellar-model-articulation-controller (CMAC) neural network (NN) based control system is developed for a speed-sensorless induction motor that is driven by a space-vector pulse-width modulation (SVPWM) inverter. By analyzing the CMAC NN structure and motor model in the stationary reference frame, the motor speed can be estimated through CMAC NN. The gradient-type learning algorithm is used to train the CMAC NN online in order to provide a real-time adaptive identification of the motor speed. The CMAC NN can be viewed as a speed estimator that produces the estimated speed to the speed control loop to accomplish the speed-sensorless vector control drive. The effectiveness of the proposed CMAC speed estimator is verified by experimental results in various conditions, and the performance of the proposed control system is compared with a new neural algorithm. Accurate tracking response and superior dynamic performance can be obtained due to the powerful online learning capability of the CMAC NN. 相似文献
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An efficient evolutionary algorithm is presented for shape optimization of transonic airfoils. Several techniques have been used to improve the efficiency and convergence rate of the optimization Genetic Algorithm (GA). A new airfoil shape parameterization method is used which is capable of producing more efficient shapes at viscous flow conditions. A Real-Coded Population Dispersion (PD) Genetic Algorithm is developed in order to increase the robustness and convergence rate of the Genetic Algorithm. A Multi-Layer Perceptron Neural Network (NN) is utilized to reduce the huge computational cost of the objective function evaluation. Further improvement in the performance of NN is obtained by using dynamic retraining and normal distribution of the training data to determine well trained parts of the design space to NN. Using the above techniques, the total computational time of optimization algorithm is reduced up to 60% compared with the conventional GA. 相似文献
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基于遗传算法的手写体汉字识别系统优化方法的研究 总被引:8,自引:0,他引:8
为了改善手写体汉字识别系统的性能,提出了前端单字识别器(SCR)和后端语言解码器(post-processing system)有效结合的模型,并且利用遗传算法对系统参数进行优化。以联机手写体汉字识别系统作为SCR进行测试,首选准确率为69.46%,汉字识别的准确率达到87.59%,较优化前提高6.4%。实验结果表明,遗传算法(GA)是一种有效的优化系统参数的方法。 相似文献
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A neural network job-shop scheduler 总被引:3,自引:2,他引:1
Gary R. Weckman Chandrasekhar V. Ganduri David A. Koonce 《Journal of Intelligent Manufacturing》2008,19(2):191-201
This paper focuses on the development of a neural network (NN) scheduler for scheduling job-shops. In this hybrid intelligent
system, genetic algorithms (GA) are used to generate optimal schedules to a known benchmark problem. In each optimal solution,
every individually scheduled operation of a job is treated as a decision which contains knowledge. Each decision is modeled
as a function of a set of job characteristics (e.g., processing time), which are divided into classes using domain knowledge
from common dispatching rules (e.g., shortest processing time). A NN is used to capture the predictive knowledge regarding
the assignment of operation’s position in a sequence. The trained NN could successfully replicate the performance of the GA
on the benchmark problem. The developed NN scheduler was then tested against the GA, Attribute-Oriented Induction data mining
methodology and common dispatching rules on a test set of randomly generated problems. The better performance of the NN scheduler
on the test problem set compared to other methods proves the feasibility of NN-based scheduling. The scalability of the NN
scheduler on larger problem sizes was also found to be satisfactory in replicating the performance of the GA. 相似文献
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