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An energy harvester combining a piezoelectric cantilever and a single degree of freedom elastic system

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第7期13卷 526-537页

作者： Hong-yan WANG Xiao-biao SHAN Tan XIE State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin 150001China College of Computer and Control Engineering Qiqihar UniversityQiqihar 161006China

This paper presents a type of vibration energy harvester combining a piezoelectric cantilever and a single degree of freedom (SDOF) elastic system. The main function of the additional SDOF elastic system is to magnify vibration displacement of the piezoelectric cantilever to improve the power output. A mathematical model of the energy harvester is developed based on Hamilton's principle and Rayleigh-Ritz method. Furthermore, the effects of the structural parameters of the SDOF elastic system on the electromechanical outputs of the energy harvester are analyzed numerically. The accuracy of the output performance in the numerical solution is identified from the finite element method (FEM). A good agreement is found between the numerical results and FEM results. The results show that the power output can be increased and the frequency bandwidth can be improved when the SDOF elastic system has a larger lumped mass and a smaller damping ratio. The numerical results also indicate that a matching load resistance under the short circuit resonance condition can obtain a higher current output, and so is more suitable for application to the piezoelectric energy harvester.

关键词： Piezoelectric cantilever Single degree of freedom elastic （SDOF） system Energy harvesting Finite element analysis（FEA）

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Preserving continuity of services exposed to security incidents

Preserving continuity of services exposed to security incide...

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6th International Conference on Emerging Security Information, Systems and Technologies, SECURWARE 2012

作者： Caban, Dariusz Walkowiak, Tomasz Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wroclaw Poland

ISBN: (纸本)9781612082097

System reconfiguration is often the only means of preserving the continuity of business-critical services after a successful penetration attack. When a fragment of the system has to be isolated (to prevent escalation of damages caused by the incident), then the other system components need to take over the functions normally performed by the affected servers. The paper addresses a specific aspect of this reconfiguration - the need to predict its impact on the availability of the services. It proposes an efficient approach, based on network simulation, for assessing the response times of services after reconfiguration. This takes into consideration the identified resource consumption interactions between the co-located services. All the presented simulation results are verified on testbed installations. The accuracy of the simulation method allows prediction of the risk of system overloading as an effect of reconfiguration.

关键词： Reconfiguration Simulation System dependability

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Motion planning of the double-link trident snake robot

Motion planning of the double-link trident snake robot

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10th IFAC Symposium on Robot control, SYROCO 2012

作者： Tchoń, Krzysztof Jakubiak, Janusz Institute of Computer Engineering Control and Robotics Wroclaw University of Technology 50-372 Wroclaw Poland

ISBN: (纸本)9783902823113

This paper addresses the motion planning problem of the trident snake robot consisting of a triangular body equipped with 2-link branches with actuated joints. The kinematics of the robot are represented by a driftless control system referred to as body controlled. This system converts to joint controlled after applying a feedback transformation. A two step motion planning strategy has been proposed to provide the joint control of the robot. First, a constrained motion planning problem is solved for the body control, preventing the feedback from getting singular, second the joint control is achieved by combining the body control with the feedback. It has been shown that the former step can be accomplished using the imbalanced Jacobian motion planning algorithm. The motion planning strategy is illustrated by computer simulations. © 2012 IFAC.

关键词： Motion planning

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Mixed parametric-nonparametric identification of Hammerstein and Wiener systems - A survey

Mixed parametric-nonparametric identification of Hammerstein...

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Universite Libre de Bruxelles

作者： Hasiewicz, Zygmunt Mzyk, Grzegorz Śliwiński, Przemyslaw Wachel, Pawel Institute of Computer Engineering Control and Robotics Wroclaw University of Technology 50-370 Wroclaw Poland

ISBN: (纸本)9783902823069

The paper surveys the ideas of cooperation between parametric and nonparametric (kernel-based) algorithms of nonlinear block-oriented system identification. Various strategies are proposed, dependently on the system structure, number of data and the prior knowledge. The estimates are consistent and their rates of convergence are presented. The aim of the paper is to show some recent results in the field in a systematic, ordered way. © 2012 IFAC.

关键词： Surveys

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2D discontinuous function approximation with real-valued grammar-based classifier system

2D discontinuous function approximation with real-valued gra...

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8th International Conference on Intelligent Computing Technology, ICIC 2012

作者： Cielecki, Lukasz Unold, Olgierd Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wybrzeze Wyspianskiego 27 50-370 Wroclaw Poland

ISBN: (纸本)9783642315879

Learning classifier systems (LCSs) are rule-based, evolutionary learning systems. Recently, there is a growing interest among the researchers in exploring LCSs implemented in a real-valued environment, due to its practical applications. This paper describes the use of a real-valued Grammar-based Classifier System (rGCS) in a task of 2D function approximation. rGCS is based on Grammar-based Classifier System (GCS), which was originally used to process context free grammar sentences. In this paper, we propose an extension to rGCS, called Simple Accept Radius (SAR) mechanism, that filters invalid and unexpected input real values. Performance evaluations show that the additional Simple Accept Radius mechanism enables rGCS to accurately approximate 2D discontinuous function. Performance comparisons with another real-valued LCS show that rGCS yields competitive performance. © 2012 Springer-Verlag.

关键词： Context free grammars

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Multi-criteria optimization in control of switched systems

Multi-criteria optimization in control of switched systems

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2012 13th International Carpathian control Conference, ICCC 2012

作者： DrĄg, Pawel Zelazny, Dominik Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Janiszewskiego 11/17 50-372 Wroclaw Poland

ISBN: (纸本)9781457718687

In the paper we present a new method for solving optimal control problems of a class of hybrid systems. We describe the new effective algorithm based on memetic algorithm (MA) for optimal control of switched systems. We concentrate on a class of problems in which a pre-specified sequence of active subsystems is known. Our aim is to find both the optimal switching instants and the optimal continuous inputs. The new approach, which we propose, decomposes the cost functional of the basic optimal control problem in Bolza form in two terms. The first term depends explicitly on a value of state variables at the final time. The second term depends on state and control trajectories. In oreder to solve those two tasks we used MA as the multi-objective optimization algorithm. In this paper we considered a fundamental bi-criteria case with two mentioned before functions: the value of state variables at the final time and the state and control trajectories. In order to find an approximation of Pareto frontier, we proposed new effective method based on genetic algorithm (GA) and local search (LS). Problems properties were taken into consideration in the design of our new approach of solving it. They were used to construct new algorithm inspired by the LS NSGA-II, which performed rather well in multi-criteria scheduling problem. Since simple genetic algorithms are efficient heuristics in searching for optimal solutions, but lack the accuracy of some more computational complex algorithms, a hybrid algorithm was constructed. It uses fast non-dominated sorting, in order to evaluate child population and allocate solutions to corresponding Pareto frontiers. I addition a local search method was used, in order to find more differentiated and better solutions. Clustering solutions from Pareto frontiers also improved diversity of solutions in child population. This approach can be used as a start point for searching for algorithm for solving optimal control problems of switched systems wi

关键词： Hybrid systems

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Topographic map object classification using real-value grammar classifier system

Topographic map object classification using real-value gramm...

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1st Indo-Japan Conference on Perception and Machine Intelligence, PerMIn 2012

作者： Cielecki, Lukasz Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wybrzeze Wyspianskiego 27 50-370 Wroclaw Poland

ISBN: (纸本)9783642273865

Learning Classifier Systems (LCS) became a large branch of machine learning applications that received a lot of attention recently. Our model of LCS - rGCS or real-value Grammar Classifier System - uses grammar inference to classify real-value vectors which may describe range variety of problems. In this paper we utilize the rGCS core in an object recognition task. Our application seeks for certain graphic symbols on a topographic map scan. © 2012 Springer-Verlag.

关键词： Object recognition

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Nonparametric identification of nonlinearity in wiener-hammerstein systems

Nonparametric identification of nonlinearity in wiener-hamme...

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9th International Conference on Informatics in control, Automation and robotics, ICINCO 2012

作者： Mzyk, Grzegorz Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wybrzeze Wyspianskiego 27 50-370 Wroclaw Poland

ISBN: (纸本)9789898565211

In the paper we recover the static characteristic of Wiener-Hammerstein (sandwich) system from inputoutput data. The system is excited and disturbed by random processes with arbitrary distribution. Two kernel-based estimates are proposed and compared. It is shown that they can successfully recover the system characteristic under small amount of a priori information about the static characteristic and the surrounding dynamic blocks. The identified nonlinear function is not parametrized and is not assumed to be invertible, which is common restriction in the literature. The orders of linear dynamic blocks are also unknown. The convergence of the estimates take place for the points in which the input probability density function in positive. The effectiveness of the algorithms is illustrated in simulation example. Copyright © 2012 SciTePress.

关键词： Random processes

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An efficient algorithm for finding minimal cycle time in cyclic job shop scheduling problem

An efficient algorithm for finding minimal cycle time in cyc...

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IEEE 16th International Conference on Intelligent Engineering Systems, INES 2012

作者： Smutnicki, Czeslaw Wroclaw University of Technology Institute of Computer Engineering Control and Robotics Janiszewskiego 11-17 50-372 Wroclaw Poland

ISBN: (纸本)9781467326957

We consider the cyclic production system providing on output the mixture of various products. Each product is produced by certain chain of operations, i. e. the unique sequence followed from the technological order. Each operations is performed on the dedicated machine. This sequence of operations is called the job. The aim is to find the cyclic schedule ensuring minimal cycle length. The problem belongs to deterministic scheduling theory, appears with the name cyclic job shop scheduling problem, is strongly NP-hard, and has been analyzed very rarely in the literature. Methodology of designing efficient optimization procedures for hard scheduling problem refers commonly to the component subproblem, namely the problem of finding cycle time or minimal cycle time for fixed job sequence. Numerical properties of this method have crucial influence on the quality of the final optimization algorithm. In this paper we propose several algorithms to solve the problem of finding cycle time for fixed job sequence. Then, we discuss and examine theoretical as well as numerical properties of these algorithms. Obtained results are illustrated by wide results of computational tests. © 2012 IEEE.

关键词： Scheduling algorithms

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Fast model order selection of the nonlinearity in Hammerstein systems

Fast model order selection of the nonlinearity in Hammerstei...

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2012 13th International Carpathian control Conference, ICCC 2012

作者： Mzyk, Grzegorz Institute of Computer Engineering Control and Robotics Wroclaw University of Technology Wybrzeze Wyspiańskiego 27 50-370 Wroclaw Poland

ISBN: (纸本)9781457718687

In the paper we show a new three-stage algorithm identifying the Hammerstein system nonlinearity. The algorithm is designed to work when a poor a priori knowledge is available and when the measurement data set is small. In the first stage, a deconvolution routine is applied to output signal in order to diminish a (usually) harmful influence of the linear dynamic component. Such filtered output is then used in a standard nonparametric estimate (be it kernel or orthogonal series one) to recover the unknown characteristics. Finally, the results of nonparametric estimation are used in the algorithm selecting the best parametric model. The entire proposed approach is illustrated by the simulation example. © 2012 IEEE.

关键词： control nonlinearities

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