Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have no...Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have not considered that the argument values may vary from profile to profile,which is common in practice.A novel nonparametric control scheme based on profile error is proposed for monitoring nonlinear profiles with varied argument values.The proposed scheme uses the metrics of profile error as the statistics to construct the control charts.More details about the design of this nonparametric scheme are also discussed.The monitoring performance of the combined control scheme is compared with that of alternative nonparametric methods via simulation.Simulation studies show that the combined scheme is effective in detecting parameter error and is sensitive to small shifts in the process.In addition,due to the properties of the charting statistics,the out-of-control signal can provide diagnostic information for the users.Finally,the implementation steps of the proposed monitoring scheme are given and applied for monitoring the blade manufacturing process.With the application in blade manufacturing of aircraft engines,the proposed nonparametric control scheme is effective,interpretable,and easy to apply.展开更多
In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust ...In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust controllers design. v-gap metric is utilized to validate the intelligently estimated uncertainty. The robust controllers are formulated within the frame- work of the standard H∞ mixed sensitivity optimization problem. Furthermore, a specially designed integral-H∞ and two-degree-of-freedom 2 DOF H∞ controllers are developed to provide improved robust performance and resolution properties. It is shown that the proposed design schemes are very effective for robust control and precise tracking performance of the servo positioning system.展开更多
The largest robust stability radius r(P0) of a system P0 is defined as the radius of the largest ball Bmax in the gap metric centered at P0 which can be stabilized by one single controller. Any controller which stabil...The largest robust stability radius r(P0) of a system P0 is defined as the radius of the largest ball Bmax in the gap metric centered at P0 which can be stabilized by one single controller. Any controller which stabilizes Bmax is called an optimally robust controller of P0. Any controller, regarded as a system, should have its own largest robust stability radius also. In this paper it is shown that the largest robust stability radius of any optimally robust controller of P0 is larger than or equal to r(Po). Moreover, the variation of the closed-loop transfer matrix caused by the perturbation of the system is estimated.展开更多
This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The p...This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The problem of the estimation of stability for this type of process is set. The central objective is to obtain a bounded stability index expressed in terms of the Lévy-Prokhorov metric;likewise, sufficient conditions are provided for the existence of such inequalities.展开更多
In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary poli...In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary policies and for the value functions, the stability index is explicitly calculated and through statistical techniques its asymptotic behavior is investigated (using numerical experiments) when the discount coefficient approaches 1. The results obtained define the conditions under which an approximate optimal stationary policy can be used to control the original process.展开更多
双母管式机组较为广泛地应用于热电联产机组中,但由于多炉多机和2根大容量母管互相影响,导致热电负荷跟踪不及时,母管压力控制自动化水平较低。为此,针对双母管系统的非线性、强耦合、大迟延特性,设计了基于广义扩张状态观测器的多模型...双母管式机组较为广泛地应用于热电联产机组中,但由于多炉多机和2根大容量母管互相影响,导致热电负荷跟踪不及时,母管压力控制自动化水平较低。为此,针对双母管系统的非线性、强耦合、大迟延特性,设计了基于广义扩张状态观测器的多模型预测控制(generalized extended state observer based muti-model predictive control,GESOMMPC)方法。首先,建立了基于间隙度量(gap-metric)的多模型控制对象用于逼近非线性系统;其次,设计了扩张状态观测器估计系统耦合的集总扰动,并作为前馈信号输入到预测控制器中;最后,设计基于扰动前馈的多模型预测控制器实现对双母管系统的控制。实验结果表明,相对于PID方法,所提方法在满足电热负荷的同时,可以在允许范围内保持母管压力稳定,且动态偏差更小,过渡过程时间更短。展开更多
针对低功耗有损网络中采用博弈论的网络拥塞控制(game theory based network congestion control protocol,GTNCC)路由算法在路由构建过程中仅仅考虑无线链路质量不能使网络拓扑最优,以及在拥塞控制过程中由拥塞节点的子节点判断是否切...针对低功耗有损网络中采用博弈论的网络拥塞控制(game theory based network congestion control protocol,GTNCC)路由算法在路由构建过程中仅仅考虑无线链路质量不能使网络拓扑最优,以及在拥塞控制过程中由拥塞节点的子节点判断是否切换父节点不能快速高效地缓解网络拥塞等问题,提出一种基于多维度量结合的集中式网络拥塞控制(centralized network congestion control based on multi-metrics combination,CNCCMC)路由协议。首先,为了降低网络拥塞发生的概率,CNCCMC路由协议综合考虑了节点剩余能量、缓存占用率、无线链路质量和中继节点当前子节点个数等多维度量完成路由构建;其次,当检测到网络拥塞时,CNCCMC路由协议依据网络拥塞节点进行流量分析和判断的结果采取集中式的方式控制其子节点的切换;最后,在网络拥塞缓解过程中,提出一种"乒乓效应"避免机制。理论分析和仿真结果表明,与GTNCC路由算法相比,CNCCMC路由协议在降低网络拥塞发生的概率、延长网络平均生存寿命和提高网络吞吐量等方面的性能得到了有效提升。展开更多
串件拼修能够在同等条件下最大限度提高装备可用度,但在装备组成结构中,并不是所有的项目都能够进行串件。为此,针对不完全串件系统,在多级维修供应模式下,根据串件拼修特点,结合可修复备件多级库存控制理论(multi-echelon theory for r...串件拼修能够在同等条件下最大限度提高装备可用度,但在装备组成结构中,并不是所有的项目都能够进行串件。为此,针对不完全串件系统,在多级维修供应模式下,根据串件拼修特点,结合可修复备件多级库存控制理论(multi-echelon theory for recoverable item control,METRIC)理论,建立了系统可用度评估模型,并研究了串件对策下最优备件方案确定流程。通过实验设计,对不同串件对策下装备的可用度进行评估,计算表明串件拼修能够进一步提高装备可用度。利用多级多层次备件库存优化工具(vary METRIC,VMETRIC)平台对模型进行验证,结果表明,本文模型结果与VMETRIC仿真结果非常吻合,证明了本文模型的正确性。展开更多
基金supported by National Natural Science Foundation of China (Grant No. 70931004,Grant No. 70802043)
文摘Profile monitoring is used to check the stability of the quality of a product over time when the product quality is best represented by a function at each time point.However,most previous monitoring approaches have not considered that the argument values may vary from profile to profile,which is common in practice.A novel nonparametric control scheme based on profile error is proposed for monitoring nonlinear profiles with varied argument values.The proposed scheme uses the metrics of profile error as the statistics to construct the control charts.More details about the design of this nonparametric scheme are also discussed.The monitoring performance of the combined control scheme is compared with that of alternative nonparametric methods via simulation.Simulation studies show that the combined scheme is effective in detecting parameter error and is sensitive to small shifts in the process.In addition,due to the properties of the charting statistics,the out-of-control signal can provide diagnostic information for the users.Finally,the implementation steps of the proposed monitoring scheme are given and applied for monitoring the blade manufacturing process.With the application in blade manufacturing of aircraft engines,the proposed nonparametric control scheme is effective,interpretable,and easy to apply.
文摘In this paper, a systematic robust control design and analysis for a single axis precise positioner is presented. The effects of uncertainties on closed-loop stability and performance are considered in the H∞ robust controllers design. v-gap metric is utilized to validate the intelligently estimated uncertainty. The robust controllers are formulated within the frame- work of the standard H∞ mixed sensitivity optimization problem. Furthermore, a specially designed integral-H∞ and two-degree-of-freedom 2 DOF H∞ controllers are developed to provide improved robust performance and resolution properties. It is shown that the proposed design schemes are very effective for robust control and precise tracking performance of the servo positioning system.
文摘The largest robust stability radius r(P0) of a system P0 is defined as the radius of the largest ball Bmax in the gap metric centered at P0 which can be stabilized by one single controller. Any controller which stabilizes Bmax is called an optimally robust controller of P0. Any controller, regarded as a system, should have its own largest robust stability radius also. In this paper it is shown that the largest robust stability radius of any optimally robust controller of P0 is larger than or equal to r(Po). Moreover, the variation of the closed-loop transfer matrix caused by the perturbation of the system is estimated.
文摘This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The problem of the estimation of stability for this type of process is set. The central objective is to obtain a bounded stability index expressed in terms of the Lévy-Prokhorov metric;likewise, sufficient conditions are provided for the existence of such inequalities.
文摘In this work, for a control consumption-investment process with the discounted reward optimization criteria, a numerical estimate of the stability index is made. Using explicit formulas for the optimal stationary policies and for the value functions, the stability index is explicitly calculated and through statistical techniques its asymptotic behavior is investigated (using numerical experiments) when the discount coefficient approaches 1. The results obtained define the conditions under which an approximate optimal stationary policy can be used to control the original process.
文摘双母管式机组较为广泛地应用于热电联产机组中,但由于多炉多机和2根大容量母管互相影响,导致热电负荷跟踪不及时,母管压力控制自动化水平较低。为此,针对双母管系统的非线性、强耦合、大迟延特性,设计了基于广义扩张状态观测器的多模型预测控制(generalized extended state observer based muti-model predictive control,GESOMMPC)方法。首先,建立了基于间隙度量(gap-metric)的多模型控制对象用于逼近非线性系统;其次,设计了扩张状态观测器估计系统耦合的集总扰动,并作为前馈信号输入到预测控制器中;最后,设计基于扰动前馈的多模型预测控制器实现对双母管系统的控制。实验结果表明,相对于PID方法,所提方法在满足电热负荷的同时,可以在允许范围内保持母管压力稳定,且动态偏差更小,过渡过程时间更短。
文摘针对低功耗有损网络中采用博弈论的网络拥塞控制(game theory based network congestion control protocol,GTNCC)路由算法在路由构建过程中仅仅考虑无线链路质量不能使网络拓扑最优,以及在拥塞控制过程中由拥塞节点的子节点判断是否切换父节点不能快速高效地缓解网络拥塞等问题,提出一种基于多维度量结合的集中式网络拥塞控制(centralized network congestion control based on multi-metrics combination,CNCCMC)路由协议。首先,为了降低网络拥塞发生的概率,CNCCMC路由协议综合考虑了节点剩余能量、缓存占用率、无线链路质量和中继节点当前子节点个数等多维度量完成路由构建;其次,当检测到网络拥塞时,CNCCMC路由协议依据网络拥塞节点进行流量分析和判断的结果采取集中式的方式控制其子节点的切换;最后,在网络拥塞缓解过程中,提出一种"乒乓效应"避免机制。理论分析和仿真结果表明,与GTNCC路由算法相比,CNCCMC路由协议在降低网络拥塞发生的概率、延长网络平均生存寿命和提高网络吞吐量等方面的性能得到了有效提升。
文摘串件拼修能够在同等条件下最大限度提高装备可用度,但在装备组成结构中,并不是所有的项目都能够进行串件。为此,针对不完全串件系统,在多级维修供应模式下,根据串件拼修特点,结合可修复备件多级库存控制理论(multi-echelon theory for recoverable item control,METRIC)理论,建立了系统可用度评估模型,并研究了串件对策下最优备件方案确定流程。通过实验设计,对不同串件对策下装备的可用度进行评估,计算表明串件拼修能够进一步提高装备可用度。利用多级多层次备件库存优化工具(vary METRIC,VMETRIC)平台对模型进行验证,结果表明,本文模型结果与VMETRIC仿真结果非常吻合,证明了本文模型的正确性。