A new fault tolerant control（FTC） via a controller reconfiguration approach for general stochastic nonlinear systems is studied.Different from the formulation of classical FTC methods,it is supposed that the measure...A new fault tolerant control（FTC） via a controller reconfiguration approach for general stochastic nonlinear systems is studied.Different from the formulation of classical FTC methods,it is supposed that the measured information for the FTC is the probability density functions（PDFs） of the system output rather than its measured value.A radial basis functions（RBFs） neural network technique is proposed so that the output PDFs can be formulated in terms of the dynamic weighings of the RBFs neural network.As a result,the nonlinear FTC problem subject to dynamic relation between the input and the output PDFs can be transformed into a nonlinear FTC problem subject to dynamic relation between the control input and the weights of the RBFs neural network approximation to the output PDFs.The FTC design consists of two steps.The first step is fault detection and diagnosis（FDD）,which can produce an alarm when there is a fault in the system and also locate which component has a fault.The second step is to adapt the controller to the faulty case so that the system is able to achieve its target.A linear matrix inequality（LMI） based feasible FTC method is applied such that the fault can be detected and diagnosed.An illustrated example is included to demonstrate the efficiency of the proposed algorithm,and satisfactory results have been obtained.展开更多
A novel strategy of probability density function （PDF） shape control is proposed in stochastic systems. The control er is designed whose parameters are optimal y obtained through the improved particle swarm optimiza...A novel strategy of probability density function （PDF） shape control is proposed in stochastic systems. The control er is designed whose parameters are optimal y obtained through the improved particle swarm optimization algorithm. The parameters of the control er are viewed as the space position of a particle in particle swarm optimization algorithm and updated continual y until the control er makes the PDF of the state variable as close as possible to the expected PDF. The proposed PDF shape control technique is compared with the equivalent linearization technique through simulation experiments. The results show the superiority and the effectiveness of the proposed method. The control er is excellent in making the state PDF fol ow the expected PDF and has the very smal error between the state PDF and the expected PDF, solving the control problem of the PDF shape in stochastic systems effectively.展开更多
目前许多信息安全产品需要根据用户权限控制其对相应文档的打印、修改、保存等子菜单操作。针对目前广泛使用的PDF文件,提出利用DDE(Dynamic Data Exchange)和Plug-in联合控制用户操作PDF文件的技术。同时提出将DDE程序生成DLL文件并引...目前许多信息安全产品需要根据用户权限控制其对相应文档的打印、修改、保存等子菜单操作。针对目前广泛使用的PDF文件,提出利用DDE(Dynamic Data Exchange)和Plug-in联合控制用户操作PDF文件的技术。同时提出将DDE程序生成DLL文件并引入用户权限的方法,再使用DLL钩挂技术,就可达到根据用户权限动态控制其对当前文件操作的目的。实践证明,这种方法可以很好地控制用户对PDF文件的相关操作。展开更多
为了稳定铜粗选选矿指标,提高矿产资源的利用水平,根据铜粗选过程中泡沫尺寸分布随药剂量改变而动态变化的特点,提出一种基于泡沫尺寸随机分布的铜粗选过程药剂量控制方法.首先,针对泡沫尺寸分布具有非高斯统计特性,基于方差和均值的统...为了稳定铜粗选选矿指标,提高矿产资源的利用水平,根据铜粗选过程中泡沫尺寸分布随药剂量改变而动态变化的特点,提出一种基于泡沫尺寸随机分布的铜粗选过程药剂量控制方法.首先,针对泡沫尺寸分布具有非高斯统计特性,基于方差和均值的统计参量难以表征该分布形态变化的问题,提出了B样条估计方法以描述泡沫尺寸的概率密度函数(Probability density function,PDF);然后,针对B样条权值相互关联的特点,建立多输出最小二乘支持向量机模型(Multi-output least square support vector machine,MLS-SVM)以表征权值和药剂量的动态关系;最后,为减少系统的随机性,采用基于熵的优化算法以确定药剂量,实现对给定泡沫尺寸分布的跟踪控制.工业数据仿真验证了所提方法的有效性,能有效稳定铜粗浮选的生产指标.展开更多
文摘间歇过程的优化控制依赖于过程精确的数学模型,数据驱动的建模方法是目前间歇过程模型研究中的热点问题。突破传统数据驱动建模方法中采用均方差(mean squared error,MSE)作为准则函数的思想,提出一种新颖的间歇过程数据驱动建模方法,引入了概率密度函数(probability density function,PDF)控制的概念,构造间歇过程模型误差控制系统,将模型的可调参数作为控制系统的输入,模型误差PDF的形状作为控制系统的输出,从而把开环模型参数辨识问题转化为模型误差PDF形状的闭环控制问题。通过可调参数控制模型误差PDF的空间分布状态,不仅能够保障模型精度,还可控制模型误差的空间分布状态,从而消除模型中的有色噪声。仿真实验表明,基于模型误差PDF形状的间歇过程数据驱动模型具有较好的建模精度、鲁棒性和泛化能力,为间歇过程的数据驱动建模提供了一条新途径。
基金supported by the UK Leverhulme Trust (F/00 120/BC)the National Natural Science Foundation of China (6082800760974029)
文摘A new fault tolerant control（FTC） via a controller reconfiguration approach for general stochastic nonlinear systems is studied.Different from the formulation of classical FTC methods,it is supposed that the measured information for the FTC is the probability density functions（PDFs） of the system output rather than its measured value.A radial basis functions（RBFs） neural network technique is proposed so that the output PDFs can be formulated in terms of the dynamic weighings of the RBFs neural network.As a result,the nonlinear FTC problem subject to dynamic relation between the input and the output PDFs can be transformed into a nonlinear FTC problem subject to dynamic relation between the control input and the weights of the RBFs neural network approximation to the output PDFs.The FTC design consists of two steps.The first step is fault detection and diagnosis（FDD）,which can produce an alarm when there is a fault in the system and also locate which component has a fault.The second step is to adapt the controller to the faulty case so that the system is able to achieve its target.A linear matrix inequality（LMI） based feasible FTC method is applied such that the fault can be detected and diagnosed.An illustrated example is included to demonstrate the efficiency of the proposed algorithm,and satisfactory results have been obtained.
基金supported by the National Natural Science Fundation of China(61273127)the Specialized Research Fund of the Doctoral Program in Higher Education(20106118110009+2 种基金20116118110008)the Scientific Research Plan Projects of Shaanxi Education Department(12JK0524)the Young Teachers Scientific Research Fund of Xi’an University of Posts and Telecommunications(1100434)
文摘A novel strategy of probability density function （PDF） shape control is proposed in stochastic systems. The control er is designed whose parameters are optimal y obtained through the improved particle swarm optimization algorithm. The parameters of the control er are viewed as the space position of a particle in particle swarm optimization algorithm and updated continual y until the control er makes the PDF of the state variable as close as possible to the expected PDF. The proposed PDF shape control technique is compared with the equivalent linearization technique through simulation experiments. The results show the superiority and the effectiveness of the proposed method. The control er is excellent in making the state PDF fol ow the expected PDF and has the very smal error between the state PDF and the expected PDF, solving the control problem of the PDF shape in stochastic systems effectively.
文摘目前许多信息安全产品需要根据用户权限控制其对相应文档的打印、修改、保存等子菜单操作。针对目前广泛使用的PDF文件,提出利用DDE(Dynamic Data Exchange)和Plug-in联合控制用户操作PDF文件的技术。同时提出将DDE程序生成DLL文件并引入用户权限的方法,再使用DLL钩挂技术,就可达到根据用户权限动态控制其对当前文件操作的目的。实践证明,这种方法可以很好地控制用户对PDF文件的相关操作。
文摘为了稳定铜粗选选矿指标,提高矿产资源的利用水平,根据铜粗选过程中泡沫尺寸分布随药剂量改变而动态变化的特点,提出一种基于泡沫尺寸随机分布的铜粗选过程药剂量控制方法.首先,针对泡沫尺寸分布具有非高斯统计特性,基于方差和均值的统计参量难以表征该分布形态变化的问题,提出了B样条估计方法以描述泡沫尺寸的概率密度函数(Probability density function,PDF);然后,针对B样条权值相互关联的特点,建立多输出最小二乘支持向量机模型(Multi-output least square support vector machine,MLS-SVM)以表征权值和药剂量的动态关系;最后,为减少系统的随机性,采用基于熵的优化算法以确定药剂量,实现对给定泡沫尺寸分布的跟踪控制.工业数据仿真验证了所提方法的有效性,能有效稳定铜粗浮选的生产指标.
