具有输入饱和的非线性关联大系统的分散控制

考虑了一类具有输入饱和的不确定非线性关联大系统的分散输出反馈鲁棒镇定问题,利用Riccati方程的方法和矩阵的Moore-Penrose逆给出了这类系统的一种分散输出反馈鲁棒镇定控制器的设计方法.同时,考虑了一类具有输入饱和的不确定非线性相似关联大系统,利用相似系统的结构特点,简化了分散输出反馈鲁棒镇定的条件.     

一类具有不确定性的非线性相似组合系统的鲁棒镇定

描述了两个控制系统间的相似性概念,讨论了一类具有不确定性的非线性相似组合 系统的鲁棒镇定问题.结果表明,作者构造的控制器具有结构相似性.相似结构确实可以简化 组合系统鲁棒镇定的判据.这说明,在一定程度上,具有相似结构的组合系统其相似结构具有 稳固系统的特性.     

不确定非线性环链系统的分散鲁棒控制

提出了环链系统和一类不确定非线性环链系统,利用线性代数理论,给出了实现环链系统的充要条件,运用李雅普诺夫稳定理论和矩阵理论研究了不确定非线性环链系统的鲁棒镇定,并给出了一种非线性鲁棒镇定控制器的设计,还考虑了一类非线性环链相似组合大系统,给出了分散鲁棒镇定条件,最后给出数值例子说明设计方法的有效性。     

一类结构不确定的非线性相似组合系统的分散鲁棒镇定

首先描述了两个控制系统的相似性概念,然后讨论了一类结构不确定的非线性相似组合系统的鲁棒镇定问题,设计出一类分散控制器,这种控制器由线性和非线性两部分组成。结果表明,相似结构确定可以简化组合系统鲁棒镇定的判据,最后的算例和仿真表明了本文结论的有效性。     

一类非线性组合大系统的分散输出反馈鲁棒镇定

研究了不确定非线性子系统经不确定非线性互联而成的组合大系统,给出了其可分 散输出反馈鲁棒镇定的充分条件,说明了所得结论的广泛适用性以及相似结构与全息特性的 密切相关性.     

一类非线性组合大系统的分散输出反馈鲁棒镇定1)

研究了不确定非线性子系统经不确定非线性互联而成的组合大系统,给出了其可分散输出反馈鲁棒镇定的充分条件,说明了所得结论的广泛适用性以及相似结构与全息特性的密切相关性.     

一类具有不确定性的复杂系统的鲁棒与反馈容错

讨论受非线性扰动的线性相似子系统经非线性互联形成的组合大系统的鲁棒反馈镇定问题. 首先给出其可用结构相似非光滑控制器进行镇定的鲁棒分散控制器设计方案, 然后给出当执行器失效时控制器的设计方案. 这种控制器不仅使正常系统保持稳定, 当执行器失效时, 也能使系统保持稳定.     

一类非线性组合大系统的分散鲁棒镇定

研究一类比较广泛的非线性组合大系统的分散鲁棒镇定问题。给出了检验这类非线性组合大系统可分散鲁棒镇定的条件,该判别条件只     

不确定非线性相似组合大系统的结构相似鲁棒控制器设计

本文研究了匹配结构不确定非线性相似组合大系统，给出其可用结构相似非光滑控制器进行镇定的鲁棒控制器设计方案及镇定域的估计方法。这种控制器由线性和非线性部分组成，其中的非线性部分类似于“砰砰”控制结构，容易实现。研究表明，相似结构能够简化非线性组合大系统的分析与设计。     

一类非线性相似组合系统的鲁棒分散控制器的设计

对于一类非线性组合系统提出了系统的相似性结构的定义,讨论了这类具有相似性 结构的非线性结构不确定组合系统的鲁棒分散镇定问题.利用系统的相似性结构,采用输入、 输出线性化与滑模控制原理相结合的方法所设计出的鲁棒分散控制器可确保闭环系统是渐 近稳定的.研究结果表明系统的相似性结构使设计的滑动面和分散控制器亦具有相似结构, 从而简化了对系统的分析与设计.     

一类不确定非线性相似组合大系统的结构相似鲁棒观测器设计

对一类不确定非线性相似组合大系统，设计出一种渐近观测器，说明在了一定条件下，相似系统存在结构相似主鲁棒观测器，并通过一个数值算例说明了本文的结论及结构相似鲁棒观测器的设计方法，仿真结果表明了所得结论的有效性。     

Decentralized output feedback robust stabilization for a class ofnonlinear interconnected systems with similarity

In this paper, the problem of decentralized output feedback stabilization for a class of nonlinear uncertain interconnected systems with similar subsystems is considered, and a type of controller with holographic structure is developed. It is shown that both the analyses of systems and the design of controllers are simplified by a similar structure. Finally, an example is presented to illustrate the results given in this paper and an estimation of the associated stabilized domain. Simulation shows that our method is very effective     

Invariant cones for non-smooth dynamical systems

In this paper we study the dynamics of piecewise linear systems with regard to generalisations of the familiar notion of Hopf bifurcation for smooth systems. It is shown that the concept of invariant planes with a change from a stable focus to an unstable focus through a center should be replaced in the case of non-smooth systems by an invariant cone with similar dynamical behaviour. In that way results for planar systems are extended into higher dimensions. To determine the invariant cone and its stability properties various extended systems are derived.     

Identification of delay dominant recycle systems

A new identification method for single-input–single-output delay dominant recycle systems is presented in this paper. Identification of recycle systems is similar to that of closed loop systems. However, identification of recycle systems poses certain challenges in that the input-equivalent signal in the closed loop identification is not available for recycle systems. Therefore, special identification routines are required to ensure consistency of recycle and forward models. It is shown that consistent estimates of delay dominant recycle systems can be obtained by treating a delayed output as one of the inputs. Asymptotic variance expressions for the estimates of forward and recycle models are provided. These are then used in designing an optimal excitation signal for recycle systems. The results are illustrated through an industrial example.     

Synchronization of decentralized multiple-model systems by market-based optimization.

Market-based optimization is a new optimization method for large decentralized systems where the distributed resource allocation of an economic system is adopted. Market-based algorithms can be interpreted as multi-agent scenarios where producer and consumer agents both compete and cooperate on a market of specified commodities. The market-based approach is applied to the synchronization of a set of local multiple-model systems. The method is extended to the case where each of the subsystems is represented by a Takagi-Sugeno (TS) fuzzy system. Although all local systems are provided with the same control input, the behaviors of the local systems are, in general, different because of different parameters in the subsystems. The task of the market-based optimization is to find an appropriate composition of subsystems so that all local systems exhibit a similar dynamical behavior. Examples show that even systems with potentially unstable local systems can be synchronized if there exists a stable combination of weighted subsystems.     

Analysis of asymmetric single-buffer polling and priority systems without switchover times

All previous works on single-buffer polling systems assume a nonzero time for a server to switch stations. In this paper, we consider similar systems with zero switchover times. The performance measures in symmetric systems of this type correspond to those in a well-known machine interference problem. Assuming that the stochastic characteristics vary from station to station, we provide an analysis of imbedded Markov chains to calculate the performance measures. In particular, we derive the state transition probabilities for systems with an arbitrary number of stations. Our approach is also applied to non-preemptive priority systems and systems with a mixture of polling and priority scheduling. Furthermore, we obtain the Laplace-Stieltjes transforms of the probability distribution function of waiting time for both polling and priority systems.     

Efficient and privacy-preserving similar electronic medical records query for large-scale ehealthcare systems

The advancements and adoption of cloud-assisted ehealthcare systems have enabled the storage of massive electronic medical records (EMRs) in the cloud for efficient and easy access. A direct benefit of EMRs is the ability of patients to search for EMRs that are similar to their own in the cloud for use as references. These similar EMRs can help a patient find appropriate medical services quickly. However, for large-scale ehealthcare systems, challenges remain with respect to ensuring the efficiency and privacy of these queries. In this study, we construct an efficient and privacy-preserving similar EMR query scheme to help patients find similar EMRs to reference in a large-scale ehealthcare system. Specifically, we propose a coarse-grained query method based on a binary decision tree to find a set of EMRs corresponding to the patient’s set of medical-symptom keywords. We also design a fine-grained query method to find similar EMRs that meet the threshold set by the patient. A detailed security analysis shows that the proposed scheme is secure. The efficiency of the proposed method in a large-scale ehealthcare system is verified experimentally.     

Sliding-mode control in discrete-state and hybrid systems

The sliding-mode control approach is developed for a class of discrete-state systems in a metric space. A concept of trajectory continuity is introduced which allows the use of sliding-mode design techniques similar to that in continuous state systems. This approach is then applied to a class of hybrid systems which consists of a continuous plant, an interface, and a discrete-state controller. The introduction of the sliding-mode concept leads to a design which is invariant to disturbances and also the solution of the stabilization problem