Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matri...Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matrix and filter parameters are difficult to be determined,which may result in filtering divergence.As to the problem that the accuracy of state estimation for nonlinear ballistic model strongly depends on its mathematical model,we improve the weighted least squares method(WLSM)with minimum model error principle.Invariant embedding method is adopted to solve the cost function including the model error.With the knowledge of measurement data and measurement error covariance matrix,we use gradient descent algorithm to determine the weighting matrix of model error.The uncertainty and linearization error of model are recursively estimated by the proposed method,thus achieving an online filtering estimation of the observations.Simulation results indicate that the proposed recursive estimation algorithm is insensitive to initial conditions and of good robustness.展开更多
针对并联型有源电力滤波器(active power filter,APF)谐波检测环节的延时和谐波电流跟踪环节的鲁棒性差、跟踪精度不高的问题,建立了系统解耦后的数学模型,提出了基于递归最小二乘(recursive least squares,RLS)算法的并联型APF全局积...针对并联型有源电力滤波器(active power filter,APF)谐波检测环节的延时和谐波电流跟踪环节的鲁棒性差、跟踪精度不高的问题,建立了系统解耦后的数学模型,提出了基于递归最小二乘(recursive least squares,RLS)算法的并联型APF全局积分滑模变结构控制策略。谐波检测环节采用改进的瞬时无功功率理论的id-iq法,用RLS自适应滤波器替换传统的Butterworth低通滤波器,解决了传统的Butterworth低通滤波器因延时而导致的一个基波周期(20 ms)内检测盲区问题。谐波电流跟踪环节采用全局积分滑模变结构控制方法,引入了全局积分滑模面,运用Lyapunov稳定性理论导出的控制律兼顾了全局滑模的快速性和积分滑模的准确性。在解决了谐波检测环节延时的情况下,将全局积分滑模控制策略与传统的PI控制和滞环控制对比,仿真实验结果表明:全局积分滑模控制对指令电流具有更高的跟踪精度,且具有更低的电网侧电流总谐波畸变率(total harmonic distortion,THD)。展开更多
字典学习是信号稀疏分解研究的热点问题.在稀疏分解字典学习中,初始字典的选择影响字典学习的效果.为减小初始字典对学习字典的影响,在递归最小二乘(recursive least squares,RLS)字典学习方法中引入遗忘因子的概念.比较了最优方向法、...字典学习是信号稀疏分解研究的热点问题.在稀疏分解字典学习中,初始字典的选择影响字典学习的效果.为减小初始字典对学习字典的影响,在递归最小二乘(recursive least squares,RLS)字典学习方法中引入遗忘因子的概念.比较了最优方向法、K奇异值分解方法和RLS等3种方法的字典学习效果.分析了RLS字典学习中不同的遗传因子对字典学习效果的影响,以及遗忘因子为不同函数时的字典学习效果.仿真结果表明:RLS字典学习方法减小了初始字典对学习结果的影响,故学习效果较好;而在RLS字典学习中不同遗忘因子的选择会影响字典学习效果.展开更多
基金This work is supported by Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX18_0467)Jiangsu Province,China.During the revision of this paper,the author is supported by China Scholarship Council(No.201906840021)China to continue some research related to data processing.
文摘Kalman filter is commonly used in data filtering and parameters estimation of nonlinear system,such as projectile's trajectory estimation and control.While there is a drawback that the prior error covariance matrix and filter parameters are difficult to be determined,which may result in filtering divergence.As to the problem that the accuracy of state estimation for nonlinear ballistic model strongly depends on its mathematical model,we improve the weighted least squares method(WLSM)with minimum model error principle.Invariant embedding method is adopted to solve the cost function including the model error.With the knowledge of measurement data and measurement error covariance matrix,we use gradient descent algorithm to determine the weighting matrix of model error.The uncertainty and linearization error of model are recursively estimated by the proposed method,thus achieving an online filtering estimation of the observations.Simulation results indicate that the proposed recursive estimation algorithm is insensitive to initial conditions and of good robustness.
文摘针对并联型有源电力滤波器(active power filter,APF)谐波检测环节的延时和谐波电流跟踪环节的鲁棒性差、跟踪精度不高的问题,建立了系统解耦后的数学模型,提出了基于递归最小二乘(recursive least squares,RLS)算法的并联型APF全局积分滑模变结构控制策略。谐波检测环节采用改进的瞬时无功功率理论的id-iq法,用RLS自适应滤波器替换传统的Butterworth低通滤波器,解决了传统的Butterworth低通滤波器因延时而导致的一个基波周期(20 ms)内检测盲区问题。谐波电流跟踪环节采用全局积分滑模变结构控制方法,引入了全局积分滑模面,运用Lyapunov稳定性理论导出的控制律兼顾了全局滑模的快速性和积分滑模的准确性。在解决了谐波检测环节延时的情况下,将全局积分滑模控制策略与传统的PI控制和滞环控制对比,仿真实验结果表明:全局积分滑模控制对指令电流具有更高的跟踪精度,且具有更低的电网侧电流总谐波畸变率(total harmonic distortion,THD)。
文摘字典学习是信号稀疏分解研究的热点问题.在稀疏分解字典学习中,初始字典的选择影响字典学习的效果.为减小初始字典对学习字典的影响,在递归最小二乘(recursive least squares,RLS)字典学习方法中引入遗忘因子的概念.比较了最优方向法、K奇异值分解方法和RLS等3种方法的字典学习效果.分析了RLS字典学习中不同的遗传因子对字典学习效果的影响,以及遗忘因子为不同函数时的字典学习效果.仿真结果表明:RLS字典学习方法减小了初始字典对学习结果的影响,故学习效果较好;而在RLS字典学习中不同遗忘因子的选择会影响字典学习效果.
