共查询到19条相似文献,搜索用时 171 毫秒
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通过设计一个非线性反馈控制器,实现了分数阶混沌系统的同步.与其他的分数阶混沌系统同步方法相比,提出的控制器设计方法保留了部分误差系统中的非线性项,而没有完全抵消同步误差系统的非线性项,有效改善了误差系统的控制性能.同时,应用区间分数阶线性时不变系统稳定性原理和线性矩阵不等式技术,得到了一个新的分数阶混沌系统同步的充分条件,进而获得的控制器保证了混沌系统同步.仿真结果验证了提出方法的有效性.
关键词:
区间分数阶时不变系统
分数阶混沌系统
混沌同步 相似文献
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提出了多核最小二乘支持向量机的永磁同步电机混沌系统建模方法. 通过不同核函数的线性加权组合构造新的等价核,降低建模精度对核函数及其参数选择的依赖性. 理论上给出多核最小二乘支持向量机回归参数和模型输出值的求解方法. 采用关联积分计算方法对永磁同步电机混沌系统进行相空间重构,以窗式移动的在线学习方式对重构后的永磁同步电机混沌序列进行一步和多步实时在线预测,并讨论了不同测量噪声对该方法的影响. 仿真结果表明,该方法能有效提高永磁同步电机混沌系统的建模精度,具有良好的抗噪能力.
关键词:
永磁同步电机
多核学习
最小二乘支持向量机
混沌预测 相似文献
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基于核学习的强大非线性映射能力,结合用于回归建模的线性偏最小二乘(PLS)算法,提出一种小波核偏最小二乘(WKPLS)回归方法. 该方法基于支持向量机使用的经典核函数技巧,将输入映射到高维非线性的特征空间,在特征空间中,构造线性的PLS回归模型. PLS方法利用输入与输出变量之间的协方差信息提取潜在特征,而可允许的小波核函数具有近似正交以及适用于信号局部分析的特性. 因此,结合它们优点的WKPLS方法显示了更好的非线性建模性能. 将WKPLS方法应用在非线性混沌动力系统建模上,并与基于高斯核的核偏最小二乘
关键词:
小波核
偏最小二乘回归
混沌系统
建模 相似文献
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本文通过设计一个新型的含分数阶滑模面的滑模控制器,应用主动控制原理和滑模控制原理,实现了一个新分数阶超混沌系统和分数阶超混沌Chen系统的投影同步.应用Lyapunov理论,分数阶系统稳定理论和分数阶非线性系统性质定理对该控制器的存在性和稳定性分别进行了分析,并得到了异结构分数阶超混沌系统达到投影同步的稳定性判据.数值仿真采用分数阶超混沌Chen 系统和一个新分数阶超混沌系统的投影同步,仿真结果验证了方法的有效性.
关键词:
分数阶滑模面滑模控制器
稳定性分析
分数阶超混沌系统
投影同步 相似文献
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从支持向量域SVD(Support Vector Domain)出发,根据Takens延时相空间重构思想,利用支持向量机非线性映射,建立了混沌时间序列和混沌非线性相轨迹运动的SVD预测模型.采用数据集作为支持对象元素,机器自学习缩小模型泛化误差的上界,利用最小二乘支持向量域(SVD),预测了Henon/Lorenz/Rossler三种混沌时间序列.预测结果表明,三种预测模型将集合映射到一个更高维特征空间,通过嵌入维数,实现了序列预测,误差随嵌入维数变化趋于恒定,与支持向量机(SVM)相比,SVD所需支持向量少,收敛速度快,鲁棒性强,核函数选择容易灵活,且存在自适应方法.网格点数提高了10—20倍,序列预测在小样本、非线性、未知概率密度条件下,预测和实际值取得了一致.
关键词:
支持向量域
混沌
最小二乘
时间序列预测 相似文献
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提出了多核最小二乘支持向量机的永磁同步电机混沌系统建模方法. 通过不同核函数的线性加权组合构造新的等价核,降低建模精度对核函数及其参数选择的依赖性. 理论上给出多核最小二乘支持向量机回归参数和模型输出值的求解方法. 采用关联积分计算方法对永磁同步电机混沌系统进行相空间重构,以窗式移动的在线学习方式对重构后的永磁同步电机混沌序列进行一步和多步实时在线预测,并讨论了不同测量噪声对该方法的影响. 仿真结果表明,该方法能有效提高永磁同步电机混沌系统的建模精度,具有良好的抗噪能力. 相似文献
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根据混沌动力系统的相空间延迟坐标重构理论,基于支持向量机的强大的非线性映射能力, 建立了混沌时间序列的支持向量机预测模型,并在统计学习理论的基础上采用最小二乘方法来训练预测模型,利用该模型对嵌入维数与模型的均方根误差的关系进行了探讨.最后利用Mackey-Glass时间序列和变参数的Ikeda 时间序列对该模型进行了验证,结果表明,该预测模型能精确地预测混沌时间序列,而且在混沌时间序列的嵌入维数未知时也能取得比较好的预测效果.这一结论预示着支持向量机是一种研究混沌时间序列的有效方法.
关键词:
混沌时间序列
支持向量机
最小二乘法 相似文献
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针对风电功率时间序列的混沌特性,提出了一种基于集成经验模态分解(ensemble empirical mode decomposition, EEMD)-近似熵和回声状态网络(echo state network, ESN) 的风电功率混沌时间序列组合预测模型.首先为降低对风电功率局部分析的计算规模以及提高预测的准确性, 利用EEMD-近似熵将风电功率时间序列分解为一系列复杂度差异明显的风电子序列; 然后对各子序列分别建立ESN、经过高频分量正则化改进的EEMD-ESN模型和最小二乘支持向量机预测模型; 最后以某一风电场实际采集的数据为算例,仿真结果表明EEMD-ESN模型在训练速度和预测精度上优于最小二乘支持向量机模型,为实现风电功率短期预测的在线工程应用提供了新的有益参考.
关键词:
混沌时间序列
风电预测
集成经验模态分解
近似熵 相似文献
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The stability control of fractional order unified chaotic system with sliding mode control theory 下载免费PDF全文
This paper studies the stability of the fractional order unified chaotic system with sliding mode control theory. The sliding manifold is constructed by the definition of fractional order derivative and integral for the fractional order unified chaotic system. By the existing proof of sliding manifold, the sliding mode controller is designed. To improve the convergence rate, the equivalent controller includes two parts: the continuous part and switching part. With Gronwall’s inequality and the boundness of chaotic attractor, the finite stabilization of the fractional order unified chaotic system is proved, and the controlling parameters can be obtained. Simulation results are made to verify the effectiveness of this method. 相似文献
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Wessel N Konvicka J Weidermann F Nestmann S Neugebauer R Schwarz U Wessel A Kurths J 《Chaos (Woodbury, N.Y.)》2004,14(1):23-29
In the last decade, there has been an increasing interest in compensating thermally induced errors to improve the manufacturing accuracy of modular tool systems. These modular tool systems are interfaces between spindle and workpiece and consist of several complicatedly formed parts. Their thermal behavior is dominated by nonlinearities, delay and hysteresis effects even in tools with simpler geometry and it is difficult to describe it theoretically. Due to the dominant nonlinear nature of this behavior the so far used linear regression between the temperatures and the displacements is insufficient. Therefore, in this study we test the hypothesis whether we can reliably predict such thermal displacements via nonlinear temperature-displacement regression functions. These functions are estimated first from learning measurements using the alternating conditional expectation (ACE) algorithm and then tested on independent data sets. First, we analyze data that were generated by a finite element spindle model. We find that our approach is a powerful tool to describe the relation between temperatures and displacements for simulated data. Next, we analyze the temperature-displacement relationship in a silent real experimental setup, where the tool system is thermally forced. Again, the ACE algorithm is powerful to estimate the deformation with high precision. The corresponding errors obtained by using the nonlinear regression approach are 10-fold lower in comparison to multiple linear regression analysis. Finally, we investigate the thermal behavior of a modular tool system in a working milling machine and again get promising results. The thermally induced errors can be estimated with 1-2 microm accuracy using this nonlinear regression analysis. Therefore, this approach seems to be very useful for the development of new modular tool systems. 相似文献
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Nonlinear parametrically excited vibration and active control of gear pair system with time-varying characteristic 下载免费PDF全文
《中国物理 B》2015,(10)
In the present work, we investigate the nonlinear parametrically excited vibration and active control of a gear pair system involving backlash, time-varying meshing stiffness and static transmission error. Firstly, a gear pair model is established in a strongly nonlinear form, and its nonlinear vibration characteristics are systematically investigated through different approaches. Several complicated phenomena such as period doubling bifurcation, anti period doubling bifurcation and chaos can be observed under the internal parametric excitation. Then, an active compensation controller is designed to suppress the vibration, including the chaos. Finally, the effectiveness of the proposed controller is verified numerically. 相似文献
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This paper studies the stability of the fractional order
unified chaotic system. On the unstable equilibrium points, the
``equivalent passivity' method is used to design the nonlinear
controller. With the definition of fractional derivatives and
integrals, the Lyapunov function is constructed by which it is
proved that the controlled fractional order system is stable. With
Laplace transform theory, the equivalent integer order state
equation from the fractional order nonlinear system is obtained, and the
system output can be solved. The simulation results validate the
effectiveness of the theory. 相似文献
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给出了准阶跃信号激励下电磁脉冲测试系统非线性模型参数在连续域的直接辨识算法。结合实际研制的光纤传输式脉冲电压测试系统及其时域动态校准数据,建立了由4阶多项式非线性环节和3阶传递函数线性环节组成的测试系统Hammerstein模型,实测结果验证了辨识模型的准确性。在此基础上,构建了由动态线性补偿滤波器和静态非线性校正器组成的补偿环节,将测试系统的下限截止频率由数十kHz拓展至直流,稳态响应时间由s级降至ns级,有效改善了系统的动态性能,实测脉冲波形的重建结果验证了补偿环节设计的有效性。 相似文献
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Dynamic analysis of a new chaotic system with fractional order and its generalized projective synchronization 下载免费PDF全文
Based on the stability theory of the fractional order system,the dynamic behaviours of a new fractional order system are investigated theoretically.The lowest order we found to have chaos in the new three-dimensional system is 2.46,and the period routes to chaos in the new fractional order system are also found.The effectiveness of our analysis results is further verified by numerical simulations and positive largest Lyapunov exponent.Furthermore,a nonlinear feedback controller is designed to achieve the generalized projective synchronization of the fractional order chaotic system,and its validity is proved by Laplace transformation theory. 相似文献
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针对强磁场实验装置(SHMFF)的链式高压有源电力滤波方案规划,基于有源滤波系统的非线性特性, 采用分数阶值。PI 控制器替代普通PI 控制器,在此基础上引入粒子群算法优化指令电流PI 控制器参数,并通过 实验对比分析了人工整定的PI 控制器与PSO 整定的PI 控制器的运行效果。经样机实验表明,采用的PSO 算法 整定的电流内环控制器是正确的,且具有一定的参考价值。 相似文献
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针对强磁场实验装置(SHMFF)的链式高压有源电力滤波方案规划,基于有源滤波系统的非线性特性, 采用分数阶值。PI 控制器替代普通PI 控制器,在此基础上引入粒子群算法优化指令电流PI 控制器参数,并通过 实验对比分析了人工整定的PI 控制器与PSO 整定的PI 控制器的运行效果。经样机实验表明,采用的PSO 算法 整定的电流内环控制器是正确的,且具有一定的参考价值。 相似文献