共查询到20条相似文献，搜索用时 31 毫秒
1.
2.
Switched systems are complicated due to the switching among the subsystems. When the subsystem models are unknown, control problems on switched systems turn to be more intractable. In this paper, the optimal switching problems are investigated for continuous-time switched autonomous systems with unknown dynamics and a finite-horizon cost function. Firstly, a novel data-driven optimal scheduling approach is proposed based on the estimated insertion gradients. Secondly, aiming at switched systems with a prescribed switching sequence, a data-driven optimal switching time approach is proposed based on the estimated derivatives of the cost with respect to the switching times. The two approaches take advantages of plenty state data containing necessary information instead of the system models. Furthermore, the errors of the approaches are analysed and bounded. Finally, simulation results of two examples are given to show the validity of the two approaches. 相似文献
3.
This paper deals with a control of coupled nonlinear identical systems that admit full exact feedback input-output linearization. The subsystems are linearized using this nonlinear transformation. In the next step, an auxiliary low-dimensional system is derived whose stability implies stability of the original large-scale system. The control law is designed so that the control loops are only local, no information exchange between subsystems is required. Unknown time delay in the feedback are allowed. Two cases are studied: equal time delay for all subsystems or different delay in all subsystems. Results are illustrated by two examples. 相似文献
4.
5.
《Journal of The Franklin Institute》1987,323(2):135-144
We consider the design of control schemes for large-scale systems composed of interconnected subsystems with time-varying uncertainties. The local control, utilizing solely the state of the subsystem, and the global control, utilizing the states of the neighboring subsystems as additional information, are proposed to guarantee certain deterministic performance, including uniform boundedness and uniform ultimate boundedness. It can be shown that the local control is applicable provided a test matrix T satisfies certain requirements. The global control, on the other hand, is applicable if the interconnections between subsystems satisfy certain structural constraints. The salient features of these control schemes is that the only information required is the bounds of uncertainties. 相似文献
6.
The purpose of designing a controller for a teleoperation system is achieving stability and optimal operation in the presence of factors such as time delay, system disturbance and modeling errors. In this article three new schemes for teleoperation systems are suggested using an optimal control to reduce the error of tracking between the master and slave systems. In the first scheme optimal controller has been designed in both the master and slave subsystems and by a suitable combination of the output signals of both controllers and exerting it to the slave, it has tried to create the best performance with regard to tracking. In the second scheme, as in the first one, optimal controller is applied to both the master and slave systems and the output of each controller is then applied to its own system, and by changing the system parameters and weighting factors, it has tried to reduce the tracking error between the master and the slave subsystems. In the third structure optimal control is applied to the master. In all three structures the positions of master-slave are compared together and controlling signals are applied to the master or slave so that they can track each other in the least possible time. In all schemes the effectiveness of the system is shown through the simulations and they are compared with each other. 相似文献
7.
Morteza Seidi 《Journal of The Franklin Institute》2011,348(7):1231-1244
The main idea of the original parallel distributed compensation (PDC) method is to partition the dynamics of a nonlinear system into a number of linear subsystems, design a number of state feedback gains for each linear subsystem, and finally generate the overall state feedback gain by fuzzy blending of such gains. A new modification to the original PDC method is proposed here, so that, besides the stability issue, the closed-loop performance of the system can be considered at the design stage. For this purpose, the state feedback gains are not considered constant through the linearized subsystems, rather, based on some prescribed performance criteria, several feedback gains are associated to every subsystem, and the final gain for every subsystem is obtained by fuzzy blending of such gains. The advantage is that, for example, a faster response can be obtained, for a given bound on the control input. Asymptotic stability of the closed loop system is also guaranteed by using the Lyapunov method. To illustrate the effectiveness of the new method, control of a flexible joint robot (FJR) is investigated and superiority of the designed controller over other existing methods is demonstrated. 相似文献
8.
9.
随着信息时代的发展,数据库的信息容量也在飞速提升。为了解决数据库中越来越多的超大表的使用和维护问题,数据库引入了分区技术。全文介绍了Oracle数据库分区的概念、表分区、索引分区以及分区策略,并结合实例给出了Oracle数据库分区具体应用。 相似文献
10.
A novel scheme is presented for solving the problem of optimal switching with nonlinear autonomous subsystems. This scheme determines the approximate global optimal solution for different initial conditions in a feedback form. Restrictions, including the need to enforce a mode sequence and/or a number of switching, do not exist for the developed method. Performance is evaluated in several examples with different complexities and the numerical simulation shows great promises for the controller. 相似文献
11.
Jianhua Wang Yan Song Guoliang Wei Yuying Dong 《Journal of The Franklin Institute》2021,358(3):1957-1983
This paper is concerned with the resilient dynamic output-feedback (DOF) distributed model predictive control (DMPC) problem for discrete-time polytopic uncertain systems under synchronous Round-Robin (RR) scheduling. In order to alleviate the computation burden and improve the system robustness against uncertainties, the global system is decomposed into several subsystems, where each subsystem under synchronous RR scheduling communicates with each other via a network. The RR scheduling is adopted to avoid data collisions, however the updating information at each time instant is unfortunately reduced, and the underlying RR scheduling of subsystems are deeply coupled. The main purpose of this paper is to design a set of resilient DOF-based DMPC controllers for systems under the consideration of polytopic uncertainties and synchronous RR scheduling, such that the desirable performance can be obtained at a low cost of computational time. A novel distributed performance index dependent of the synchronous RR scheduling is constructed, where the last iteration information from the neighbor subsystems is used to deal with various couplings. Then, by resorting to the distributed RR-dependent Lyapunov-like approach and inequality analysis technique, a certain upper bound of the objective is put forward to establish a solvable auxiliary optimization problem (AOP). Moreover, by using the Jacobi iteration algorithm to solve such a problem online, the distributed feedback gains are directly obtained to guarantee the convergence of system states. Finally, two examples including a distillation process example and a numerical example are employed to show the effectiveness of the proposed resilient DMPC strategy. 相似文献
12.
高校科研团队学术生态系统协同演化 总被引：1，自引：1，他引：0
针对高校科研团队影响力越来越大的特点,对高校科研团队生态系统的内涵、主体和环境以及系统各要素进行分析,从生态学视角对其发展和演化过程进行了剖析,借鉴lotka-Volterra模型,对其各子系统之间的竞争合作关系进行协同演化研究,从竞争、合作以及竞争合作三个方面进行建模分析,获得各种条件下的最优协同组合,为高校科研团队学术系统健康运行提供借鉴。 相似文献
13.
Yuanhong Ren Weiqun Wang Yixiang Wang Mingxuan Shen 《Journal of The Franklin Institute》2018,355(15):7134-7157
In this paper, we investigate the incremental H∞ performance problem for a class of stochastic switched nonlinear systems by using a state-dependent switching law and the maximum and minimum dwell time approach. By resorting to the state-dependent switching law, some sufficient conditions are provided to cope with the incremental H∞ performance problem, which can be applied even if all subsystems are unstable. Then, based on the maximum and minimum dwell time scheme, the incremental H∞ performance problem to be solvable is derived for two cases: one is all subsystems are incrementally globally asymptotically stable in the mean(IGASiM), another is both IGASiM subsystems and unstable subsystems coexist. When all subsystems are IGASiM, the stochastic switched nonlinear system is IGASiM and possesses a incremental L2-gain under given conditions. When both IGASiM subsystems and unstable subsystems coexist, if the activation time ratio between IGASiM subsystems and unstable ones is not less than a specified constant, the sufficient conditions for the incremental H∞ performance of the stochastic switched nonlinear system are given. Two numerical examples are given to illustrate the validity of methods proposed. 相似文献
14.
This paper addresses the problem of decentralized guaranteed cost stabilization (DGCS) of large-scale systems with delays both in the isolated subsystems and interconnections based on reduced-order observers. Sufficient conditions for the existence of delay-independent decentralized guaranteed cost controller (DGCC) are given in terms of linear matrix inequalities (LMIs). Furthermore, a convex optimization problem with LMIs constraints is formulated to design the optimal DGCC which minimizes the guaranteed cost of the closed-loop large-scale systems. Finally, a simulation is performed to show the effectiveness of the proposed control scheme. 相似文献
15.
《Information processing & management》2016,52(6):1031-1052
In this paper, we introduce a new collection selection strategy to be operated in search engines with document partitioned indexes. Our method involves the selection of those document partitions that are most likely to deliver the best results to the formulated queries, reducing the number of queries that are submitted to each partition. This method employs learning algorithms that are capable of ranking the partitions, maximizing the probability of recovering documents with high gain. The method operates by building vector representations of each partition on the term space that is spanned by the queries. The proposed method is able to generalize to new queries and elaborate document lists with high precision for queries not considered during the training phase. To update the representations of each partition, our method employs incremental learning strategies. Beginning with an inversion test of the partition lists, we identify queries that contribute with new information and add them to the training phase. The experimental results show that our collection selection method favorably compares with state-of-the-art methods. In addition our method achieves a suitable performance with low parameter sensitivity making it applicable to search engines with hundreds of partitions. 相似文献
16.
The lexical problems in large information systems are created by the necessity of handling a great number of names and their interrelations. Such lexical problems are not covered completely by the concept of data dictionaries, which are mostly concerned with database schema design rather than the execution of operations. In this paper we introduce our view of a lexical subsystem as a separate component in an information system architecture, to deal with linguistic and control functions concerning the lexical problems in local and network environments. The lexical subsystem is a special efficiently organized program package, which plays the role of a “linguistic filter” in a broad sense for lexically incorrect queries, promotes integration of databases and information retrieval systems, and facilitates the creation of local information systems. We hope that lexical subsystems can become productive for any large, especially distributed, information system. 相似文献
17.
高校的教务服务水平对学校教师教学以及学生学习的正常开展起着十分重要的作用。但当前,地方高校的教务服务存在着制度缺乏、人才不足、质量难控、信息孤立四方面的问题。因此,需要构建以制度保障、人才保障、质量监控保障、信息化保障四个子体系为内容的高校教务服务保障体系。 相似文献
18.
硬盘分区实质上是对硬盘的一种格式化,然后才能使用硬盘保存各种信息。目前硬盘的容量越来越大,都是几百GB以上甚至达到了TB级的超大容量硬盘,因此,硬盘的合理分区就显得非常必要了。一般情况下,对于大容量硬盘我们认为划为六个分区是比较合理的,对于过多的分区是不利于进行磁盘管理和磁盘维护的。此外,还可以利用Win7自带的磁盘管理工具,来很好地完成分区调整、格式化等工作,而不需要借助第三方软件进行分区和格式化。 相似文献
19.
A backstepping-based adaptive neural network decentralized stabilization approach is presented for the expanding construction of a class of nonlinear large scale interconnected systems in this paper. The expanding construction of large scale interconnected systems is to add some new subsystems into the original system during the operation of the original system. For stabilization of the expanding system, it is more realistic to keep the decentralized control laws of the original subsystems unchanged. And the decentralized control laws of the new subsystems must be designed to stabilize both itself and the resultant large scale system. In this paper, neural networks are used to approximate the unknown nonlinear functions in the new subsystems and the unknown nonlinear interconnection functions. The decentralized control laws and the parameter adaptive laws of the new subsystems are designed by using backstepping technique for the expanding construction of the large-scale interconnected system. Based on Lyapunov stability theory, the uniform and ultimate boundedness of all signals in the closed-loop system is proved. Two illustrative examples show the feasibility of the presented approach. 相似文献
20.
分散控制下的信息共享和集中控制下的共同决策是供应链系统协调的两种重要策略。本文以供应链系统中制造商和零售商之间的Stackelberg博弈模型为基础,研究了随机产品需求条件下信息共享协调与共同决策协调对最优批发价格、最优订货量,以及对制造商、零售商和供应链系统利润的影响,分析了信息共享的条件,提出了共同决策协调下供应链系统利润的两种分割方法:比例系数方法和批发价格协商方法。然后,通过以产品随机需求服从均匀分布情形下模型的计算与仿真进一步证实了理论分析结果。结果表明,信息共享对于制造商而言总是有利的,制造商通过信息共享能够确定其最优产品批发价格并实现其利润最大化,但信息共享的前提是零售商的利润能够得到改善。共同决策协调能够实现供应链系统利润最大化。利润分割系数与批发价格都存在较宽的取值区间可使制造商和零售商在利润分割时能实现"双赢"。供应链系统利润随产品随机需求量期望的增大而增加,随标准差的增大而减小。从供应链系统利润最大化视角来看,共同决策协调优于信息共享协调。 相似文献