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A MIXED TIME-CONDITION- BASED PRECOGNITIVE MAINTENANCE FRAMEWORK FOR ZERO-BREAKDOWN INDUSTRIAL SYSTEMS

control AND INTELLIGENT SYSTEMS 2013年第3期41卷 1-1页

作者： Pang, Chee Khiang Zhou, Jun-Hong Wang, Xiaoyun Department of Electrical and Computer Engineering National University of Singapore Singapore Singapore Manufacturing Execution and Control Group A-STAR Singapore Institute of Manufacturing Technology Singapore Singapore

Forecasting of process outages for reducing downtime and machine scrap parts have been actively pursued in the manufacturing industries to ensure that maintenance is carried out only when required. In this paper, we propose a precognitive maintenance framework based on mixed time- and condition-based models to predict both wear and degradation stage of realistic engineering systems. The decision-making framework performs stage classification using support vector machines and wear estimation using time-based autoregressive moving average with exogenous inputs models. Our proposed framework is supported by mathematical rigour, and its effectiveness is evaluated with experimental results on a high-speed industrial computer numerical control milling machine for tool wear stage identification and wear estimation. [PUBLICATION ABSTRACT]

关键词： ARMAX model classification condition-based maintenance pre-cognitive maintenance support vector machine tool conditionmonitoring

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Closed-loop control of a novel 2-DOF MEMS nanopositioner with electrothermal actuation

Closed-loop control of a novel 2-DOF MEMS nanopositioner wit...

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6th IFAC Symposium on Mechatronic Systems, MECH 2013

作者： Fowler, Anthony G. Rakotondrabe, Micky Moheimani, S.O. Reza School of Electrical Engineering and Computer Science University of Newcastle Callaghan NSW 2308 Australia FEMTO-ST Institute UMR CNRS 6174 - UFC / ENS MM / UTBM Automatic Control and Micro-Mechatronic Systems Depart. AS2M 25000 Besancon France

ISBN: (纸本)9783902823311

The design, characterization and control of a novel 2-DOF MEMS nanopositioner is presented, with Z-shaped electrothermal actuators being used to position the device's central stage. Whereas the more commonly-used V-shaped electrothermal actuator only allows displacements in one direction, the design of the Z-shaped beams used in the presented device allows two actuators to be coupled back-to-back to achieve bidirectional motion along each of the two axes. Testing of the device shows that stage displacements in excess of ± 5 μm are achievable for both the x and y axes. The device features integrated displacement sensors based on polysilicon electrothermal heaters, which are supplied with an electrical bias voltage that results in Joule heating. The resistance of each heater varies depending on the position of the central stage, with two heaters being used per axis in a differential configuration. The displacement measurements are utilized as part of an implemented closed-loop control scheme that uses both feedforward and feedback mechanisms based on the principle of internal model control. Experimental testing shows that the use of the controller enhances the static and dynamic performance of the system, with particular improvements being seen in the device's reference tracking, response time and cross-coupling rejection. © 2013 IFAC.

关键词： Feedback

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Beyond bag of words: Image representation in sub-semantic space 13

Beyond bag of words: Image representation in sub-semantic sp...

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21st ACM International Conference on Multimedia, MM 2013

作者： Zhang, Chunjie Wang, Shuhui Liang, Chao Liu, Jing Huang, Qingming Li, Haojie Tian, Qi School of Computer and Control Engineering University of Chinese Academy of Sciences 100049 Beijing China Key Lab of Intell. Info. Process Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China School of Computer National Engineering Research Center for Multimedia Software Wuhan University 430072 Wuhan China National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing China School of Software Dalian University of Technology Liaoning China Department of Computer Sciences University of Texas San Antonio TX 78249 United States

ISBN: (纸本)9781450324045

Due to the semantic gap, the low-level features are not able to semantically represent images well. Besides, traditional semantic related image representation may not be able to cope with large inter class variations and are not very ro- bust to noise. To solve these problems, in this paper, we propose a novel image representation method in the sub- semantic space. First, examplar classifiers are trained by separating each training image from the others and serve as the weak semantic similarity measurement. Then a graph is constructed by combining the visual similarity and weak se- mantic similarity of these training images. We partition this graph into visually and semantically similar sub-sets. Each sub-set of images are then used to train classifiers in order to separate this sub-set from the others. The learned sub-set classifiers are then used to construct a sub-semantic space based representation of images. This sub-semantic space is not only more semantically meaningful but also more reli- Able and resistant to noise. Finally, we make categorization of images using this sub-semantic space based representation on several public datasets to demonstrate the e®ectiveness of the proposed method. Copyright © 2013 ACM.

关键词： Image representation

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Applications Oriented Stability Theory for Discrete Linear Repetitive Processes

Applications Oriented Stability Theory for Discrete Linear R...

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nDS '13;Proceedings of the 8th International Workshop on Multidimensional Systems

作者： Pawel Dabkowski Krzysztof Galkowski Eric Rogers Institute of Physics. Nicolaus Copernicus University in Torun Poland and Department of Control Engineering Faculty of Electrical Engineering Czech Technical University in Prague Institute of Control and Computation Engineering University of Zielona Gora and Institute of Physics. Nicolaus Copernicus University in Torun Electronics and Computer Science University of Southampton

Many systems repeat the same operation over and over again on a finite duration. Repetitive processes have this characteristic where repeated sweeps, termed passes, are made over the finite pass length and when each is complete the process resets to the starting location and the next pass begins. The distinguishing feature of these processes is that the output, or pass profile, produced on each pass explicitly contributes to the dynamics of the next one and can result in oscillations that increase in amplitude from pass-to-pass. For applications, it is necessary to have a stability theory on which to base control law design for stabilization and performance. This paper gives a reflective overview of the stability theory for linear repetitive processes with particular attention to the forms of stability possible, their characterizations, and suitability for control law design. A particular feature is that the strongest form of stability for these processes can, especially for applications, lead to difficulties in control law design for stability and performance. One alternative in such cases is also considered.

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Iterative Learning control Design for Stability and Transient Performance Using Differential Linear Repetitive Process Stability Theory

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IFAC Proceedings Volumes 2013年第11期46卷 152-157页

作者： Wojciech Paszke Krzysztof Gałkowski Eric Rogers Institute of Control and Computation Engineering University of Zielona Góra Poland Electronics and Computer Science University of Southampton Southampton SO17 1BJ UK

Iterative learning control has been developed for systems that repeat the same task over a finite duration with resetting to the starting location once each repetition, or trial, is complete. The novel feature is the use of information generated on the previous trial to compute the control input for the next one and the basic problem is to force the sequence of trial outputs to track a given reference signal. In many cases, it is also necessary to regulate the dynamics produced along the trials, for which this paper gives new results using the theory of linear repetitive processes and the generalized form of the Kalman-Yakubovich-Popov lemma.

关键词： iterative learning control convergence control law design

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Joint optimization toward effective and efficient image search

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IEEE Transactions on Cybernetics 2013年第6期43卷 2216-2227页

作者： Wei, Shikui Xu, Dong Li, Xuelong Zhao, Yao Institute of Information Science Beijing Jiaotong University Beijing Key Laboratory of Advanced Information Science and Network Technology Beijing 100044 China School of Computer Engineering Nanyang Technological University 639798 Singapore Singapore Center for OPTical IMagery Analysis and Learning State Key Laboratory of Transient Optics and Photonics Xi'An Institute of Optics and Precision Mechanics Xi'an 710119 China Institute of Information Science Beijing Jiaotong University Beijing 100044 China State Key Laboratory of Rail Traffic Control and Safety Beijing 100044 China

The bag-of-words (BoW) model has been known as an effective method for large-scale image search and indexing. Recent work shows that the performance of the model can be further improved by using the embedding method. While different variants of the BoW model and embedding method have been developed, less effort has been made to discover their underlying working mechanism. In this paper, we systematically investigate the image search performance variation with respect to a few factors of the BoW model, and study how to employ the embedding method to further improve the image search performance. Subsequently, we summarize several observations based on the experiments on descriptor matching. To validate these observations in a real image search, we propose an effective and efficient image search scheme, in which the BoW model and embedding method are jointly optimized in terms of effectiveness and efficiency by following these observations. Our comprehensive experiments demonstrate that it is beneficial to employ these observations to develop an image search algorithm, and the proposed image search scheme outperforms state-of-the-art methods in both effectiveness and efficiency. © 2013 IEEE.

关键词： Image enhancement

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An Event-Based Online Scheduling Approach for Networked Embedded control Systems

An Event-Based Online Scheduling Approach for Networked Embe...

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American control Conference

作者： Sven Reimann Sanad Al-Areqi Steven Liu Institute of Control Systems Department of Electrical and Computer Engineering University of Kaiserslautern Erwin-Schroedinger-Str. 12 67663 Kaiserslautern Germany

ISBN: (纸本)9781479901777

In networked embedded control systems (NECSs) where a number of independent control loops are closed over a shared communication network, guaranteeing a stable behavior of the closed-loop trajectories with some level of performance through a suitable optimal control law is an essential objective. Relying only on the controller while neglecting the switching mechanism between the associated control loops may lead to a deficient control performance. Joint design of a control law and an offline/online scheduling law can improve the control performance significantly. Using either offline scheduling or online scheduling, however, may not achieve the best reachable performance. Therefore, an event-based online scheduling approach, jointly with a control design, is proposed in this paper to improve the resulting performance. The main idea is to balance between offline scheduling and online scheduling such that the advantages of each are preserved. The proposed codesign strategy is formulated as an LMI optimization problem and evaluated through simulating a networked embedded control of a set of inverted pendulums. Notably, the proposed theory is also generally applicable to discrete-time switched linear systems.

关键词： NECSs closed-loop advantages control systems CLOSED LOOP control performance control ring control law networks(communications) Event-based design control embedding Level of Performance

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An Object-Oriented Design Method for Fault Detection and Isolation

An Object-Oriented Design Method for Fault Detection and Iso...

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IEEE Annual Conference on Decision and control

作者： Stefan Simon Steven Liu Institute of Control Systems Department of Electrical and Computer Engineering University of Kaiserslautern Erwin-Schrodinger-Str. 12 67663 Kaiserslautern Germany

ISBN: (纸本)9781467357159

In this paper an object-oriented (OO) Fault Detection and Isolation (FDI) method for complex systems is developed. Examples of such systems are mechatronic systems, commercial vehicles and chemical process plants. Such systems consist of numerous subsystems from different physical domains. Each subsystem is described by an object. The mathematical composition of these objects results in a differential algebraic equation (DAE) which describes the overall system. This DAE is automatically analyzed and transformed into a set of residual generators (RG) in integral causality which meet a given isolability specification.

关键词： Defect detection design approach object-oriented design Complex systems SUB-SYSTEM differential algebraic equations Commercial vehicles AUTOMATIC

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Computational methods for adaptation of markov models to requested maintenance policies

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computer Modelling and New Technologies 2013年第1期17卷 14-24页

作者： Sugier, J. Wroclaw University of Technology Institute of Computer Engineering Control and Robotics Janiszewskiego St. 11/17 50-372 Wroclaw Poland

State-transition models are often used in reliability analysis and one specific approach of this kind is the subject of this paper. By incorporating elements of both the deterioration process and the maintenance activities (inspections and repairs) in a semi-Markov model, a common computational platform has been created which serves as a foundation for various dependability studies that can investigate different maintenance scenarios. Having available some basic model it is possible to adjust its parameters so that it represents some hypothetical new maintenance policy and then to examine an impact which changing to the new policy has on various reliability characteristics of the system. Particularly, this paper discusses an extension of the generic adjustment algorithm to specific situations of the so-called model saturation when, as a result of tweaking the model towards higher repair frequencies, sum of repairs probabilities in the states reach the maximum value and there is no room for further increase. The general idea is to modify the model in such cases by forcing some non-zero value of a repair probability in those states where it is zero initially but in a manner that will not destroy the overall model behaviour. After theoretical presentation of the modified method its effectiveness is illustrated on practical examples. It is shown that the proposed extension allows to successfully evaluating a class of cases that has not been properly handled by the generic method and thus broadens the range of dependability studies that can be effectively evaluated.

关键词： Repair

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Output-based control and Scheduling Codesign for control Systems Sharing a Limited Resource

Output-based Control and Scheduling Codesign for Control Sys...

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IEEE Annual Conference on Decision and control

ISBN: (纸本)9781467357159;9781467357159

This paper addresses the output-based control and scheduling codesign problem for control systems sharing a limited resource, especially embedded control systems (ECSs). The joint design (codesign) of a controller and a scheduler is for the purpose of improving the resulting control performance. ECSs with a set of independent linear time-invariant plants and considerable computation time delays are modeled as discrete-time switched linear systems. Based on the resulting model, the codesign problem is introduced and decomposed into a state-based control and scheduling codesign subproblem and an observer design subproblem using the separation principle. Both subproblems are eventually formulated as LMI subproblems which can be solved efficiently. Two types of observers are introduced to cope with the lack of all states: Prediction observer and current-state observer. The effectiveness of the proposed output-based codesign method is illustrated for simultaneous stabilization of three inverted pendulums.

关键词： control systems Observers scheduler program discrete-time Linear system INVERTED PENDULUM controllers

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