A virtual closed loop method for closed loop identification

Indirect methods for the identification of linear plant models on the basis of closed loop data are based on the use of (reconstructed) input signals that are uncorrelated with the noise. This generally requires exact (linear) controller knowledge. On the other hand, direct identification requires exact plant and noise modelling (system in the model set) in order to achieve accurate results, although the controller can be non-linear. In this paper, a generalized approach to closed loop identification is presented that includes both methods as special cases and which allows novel combined methods to be generated. Besides providing robustness with respect to inexact controller knowledge, the method does not rely on linearity of the controller nor on exact noise modelling. The generalization is obtained by balancing input-noise decorrelation against noise whitening in a user-chosen flexible fashion. To this end, a user-chosen virtual controller is used to parametrize the plant model, thereby generalizing the dual-Youla method to cases where knowledge of the controller is inexact. Asymptotic bias and variance results are presented for the method. Also, the benefits of the approach are demonstrated via simulation studies.     

Controller order reduction with guaranteed performance via coprime factorization

In this paper the problems of the suboptimal H_∞ controller order reduction and strictly positive real (SPR) controller order reduction via coprime factorization are studied. The sufficient conditions to ensure the reduced order controllers also being suboptimal H_∞ controllers and SPR are given, respectively. The conditions presented may be considered as frequency weighted model reduction problems. We generalize the result of C?(θ) approach in Goddard (Ph.D. Thesis, Trinity College, Cambridge, 1995) for controller order reduction with an H_∞ framework and the relationship between our results and some other existing results is established. Copyright © 2003 John Wiley & Sons, Ltd.     

Continuous-time model identification for closed loop control performance assessment

The paper describes a system identification procedure for continuous-time transfer function models and demonstrates how it can be used for control performance assessment. Two normalized indices are derived for detecting oscillations and sluggish performance. The methods are designed for single-input single-output (SISO) control loops that experience periodic setpoint changes. An advantage of the system identification procedure is that it can operate on irregularly sampled data. The paper presents results from simulation tests and from tests on an heating, ventilating, and air-conditioning (HVAC) system serving a large commercial office building.     

loss-averse测度的低碳闭环供应链最优减排研究

以低碳产品销售为不确定市场环境为背景,以Stackelberg博弈理论为方法,以loss-averse为工具,构建了双第三方回收低碳风险再制造闭环供应链模型,研究了制造商低碳减排能力、碳排放征税政策、销售商风险厌恶程度和废旧低碳产品回收市场竞争特性等因素的影响作用机理;揭示非合作博弈和协调运作下,订单数量、交易价格、低碳废旧产品回收价格等重要变量和节点企业收益、期望效用及整个链条收益的变化规律及隐含的经济意义与管理理念。设计正向渠道收益共享、逆向渠道风险共担契约,克服风险规避效应和双重边际效应的不利影响,实现低碳再制造闭环供应链的协调;通过数值仿真研究和灵敏度分析,验证了低碳风险再制造闭环供应链模型的有效性及实用性,为供应链上下游企业开展低碳减排合作提供了理论依据和政策建议。     

Controller design with regional pole constraints

A design procedure is developed that combines linear-quadratic optimal control with regional pole placement. Specifically, a static and dynamic output-feedback control problem is addressed in which the poles of the closed-loop system are constrained to lie in specified regions of the complex plane. These regional pole constraints are embedded within the optimization process by replacing the covariance Lyapunov equation by a modified Lyapunov equation whose solution, in certain cases, leads to an upper bound on the quadratic cost functional. The results include necessary and sufficient conditions for characterizing static output-feedback controllers with bounded performance and regional pole constraints. Sufficient conditions are also presented for the fixed-order (i.e. full- and reduced-order) dynamic output-feedback problem with regional pole constraints. Circular, elliptical, vertical strip, parabolic, and section regions are considered     

Order reduction in linear state estimation under performance constraints

The design and analysis of minimal-order state estimators for possibly time-varying linear systems, under constraints on the maximal allowable mean-square error, are considered. A global lower bound on the optimal error is derived, along with a lower bound on the minimal estimator order, needed for meeting the performance constraint. The ideal reduced-order estimator which satisfies the lower bound is derived, along with conditions for its realizability. When the ideal estimator is not realizable, its structure forms a suboptimal estimator, which maintains, in some sense, a local optimality property and is called the pseudoideal estimator. The mean-square error of the pseudoideal estimator defines upper bounds on the optimal error and on the estimator order needed for meeting the performance constraint. The lower and the upper bounds on the order define a reduced search set for the design problem. When the distance between the ideal and the pseudoideal estimators is sufficiently small in a certain numerical sense, the pseudoideal estimator may be considered optimal for practical purposes.     

Controller synthesis with guaranteed closed-loop phase constraints

In this paper, we present an analysis and synthesis approach for guaranteeing that the phase of a single-input, single-output closed-loop transfer function is contained in the interval [−α,α] for a given α>0 at all frequencies. Specifically, we first derive a sufficient condition involving a frequency domain inequality for guaranteeing a given phase constraint. Next, we use the Kalman–Yakubovich–Popov theorem to derive an equivalent time domain condition. In the case where , we show that frequency and time domain sufficient conditions specialize to the positivity theorem. Furthermore, using linear matrix inequalities, we develop a controller synthesis approach for guaranteeing a phase constraint on the closed-loop transfer function. Finally, we extend this synthesis approach to address mixed gain and phase constraints on the closed-loop transfer function.     

Mining lossless closed frequent patterns with weight constraints

Frequent pattern mining is one of main concerns in data mining tasks. In frequent pattern mining, closed frequent pattern mining and weighted frequent pattern mining are two main approaches to reduce the search space. Although many related studies have been suggested, no mining algorithm considers both paradigms. Even if closed frequent pattern mining represents exactly the same knowledge and weighted frequent pattern mining provides a way to discover more important patterns, the incorporation of closed frequent pattern mining and weight frequent pattern mining may loss information. Based on our analysis of joining orders, we propose closed weighted frequent pattern mining, and present how to discover succinct but lossless closed frequent pattern with weight constraints. To our knowledge, ours is the first work specifically to consider both constraints. An extensive performance study shows that our algorithm outperforms previous algorithms. In addition, it is efficient and scalable.     

Routing with multiple quality-of-services constraints: An approximation perspective

Finding a path that satisfies multiple Quality-of-Service (QoS) constraints is vital to the deployment of current emerged services. However, existing algorithms are not very efficient and effective at finding such a path. Moreover, few works focus on three or more QoS constraints. In this paper, we present an enhanced version of fully polynomial time approximation scheme (EFPTAS) for multiconstrainted path optimal (MCOP) problem. Specifically, we make four major contributions. We first allow the proposed algorithm to construct an auxiliary graph, through which the QoS parameters on each of the finding path can be guaranteed not to exceed the given constraints. Then we adopt a concept, called nonlinear definition of path constraints in EFPTAS for reducing both time and space complexity. Also, we enable EFPTAS to run iteratively to facilitate a progressive refinement of the finding result. In addition to these, we identify some “deployment” issues for proposed algorithm, the essential steps that how and when the EFPTAS takes place are presented. By analyzing the proposed algorithm theoretically, we find that the presented EFPTAS can find a (1+ε)-approximation path in the network with time complexity O(|E||V|/ε) (where |E| is the number of edges and |V| is the number of nodes), which outperforms the previous best-known algorithm for MCOP. We conduct an extensive comparison between the algorithm presented in this paper and previous best-known study experimentally, our results indicate that EFPTAS can find a path with low complexity and preferable quality.     

An IS case: The closed loop scenario

Organizations are exploring the potential of inter-organizational information systems (IS^*s) in greater numbers. Generally the incentives are cost reduction and/or productivity improvement. Gaining these potential benefits requires cooperation within the information exchange path. Potential barriers, however, are the recognition of an information processing problem and the readiness to accept automated solutions.     

A closed loop exponential feeding law: Invariance and global stability analysis

This article addresses the computation of invariant control laws [A. Fradkov, I. Miroshnik, V. Nikiforov, Nonlinear and Adaptive Control of Complex Systems, Kluwer, 1999] for fed-batch fermenters represented by two standard models. It will be shown how to derive partial state feedbacks that, assuming ideal conditions and perfect model, keep the specific growth rate μ constant provided the initial conditions are adequate. The invariant control law is the closed loop version of the exponential feeding already suggested in several references as shown later. The paper presents an analysis of invariance and a study of global stability within the framework of partial stability. That is, stability with respect to some of the state variables. This enables us to treat the case with Haldane-like or non-monotonous kinetics.     

Stochastic modeling and prediction of IMEP for closed loop knock control performance assessment

Knock control systems aim to maximize power output while also protecting the engine from knock-induced damage. The extent to which this goal is achieved is rarely evaluated, both because the random nature of knock events means that the results of any single experiment are not repeatable, and because control loop performance is generally assessed with respect to the resultant spark angle (the manipulated variable), rather than some measure of output performance. In this work, a new stochastic model for the empirical IMEP distribution is developed and fitted to open-loop experimental data. Stochastic methods are then applied to predict both the steady state and transient closed loop distribution of IMEP based on the open-loop model and the control law that is applied. The results are validated against closed loop data gathered from the engine and show good agreement with the data.     

A phase-locked loop using ESO-based loop filter for grid-connected converter:performance analysis

An extended state observer(ESO)-based loop filter is designed for the phase-locked loop(PLL)involved in a disturbed grid-connected converter(GcC).This ESO-based...     

闭环控制微波理疗机的设计

介绍了一种基于PIC16F877高性能单片机控制的微波理疗机的设计及系统工作原理,提出了闭环反馈功率控制方案,并较为详细的阐述了系统数据采集、D/A转换、功率调节等硬件电路设计,同时还指出了软件实现的特点。该理疗机输出功率范围为30~150W,并具有数字显示,报警提示等功能。     

Controller reduction: concepts and approaches

The problem of passing from a linear time-invariant high-order controller designed for a linear time-invariant plant (of presumably high order) to a low-order approximation of the controller is discussed. The approximation problem is often best posed as a frequency-weighted L_∞ approximation problem. Many different controller representations are possible, giving different performances of the various reduction algorithms     

An IS1 case: The closed loop scenario

Organizations are exploring the potential of inter-organizational information systems (IS¹s) in greater numbers. Generally the incentives are cost reduction and/or productivity improvement. Gaining these potential benefits requires cooperation within the information exchange path. Potential barriers, however, are the recognition of an information processing problem and the readiness to accept automated solutions.     

A new closed loop method of super-resolution for multi-view images

In this paper, we propose a closed loop method to resolve the multi-view super-resolution problem. For the mixed-resolution multi-view case, where the input is one high-resolution view along with its neighboring low-resolution views, our method can give the super-resolution results and obtain a high-quality depth map simultaneously. The closed loop method consists of two parts: part I, stereo matching and depth maps fusion; and part II, super-resolution. Under the guidance of the estimated depth information, the super-resolution problem can be formulated as an optimization problem. It can be solved approximately by a three-step method, which involves disparity-based pixel mapping, nonlocal construction and final fusion. Based on the super-resolution results, we can update the disparity maps and fuse them into a more reliable depth map. We repeat the loop several times until obtaining stable super-resolution results and depth maps simultaneously. The experimental results on public dataset show that the proposed method can achieve high-quality performance at different scale factors.