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16th International Congress on Sound and Vibration 2009, ICSV 2009

作者： Soorgee, M.H. Yousefi-Koma, A. Advanced Dynamic and Control Systems Lab. Faculty of Mechanical Eng. University of Tehran P. Box 11365-4563 Tehran Iran

ISBN: (纸本)9781615677368

In this paper a new method for crack detection in shell like structures based on lamb wave propagation and neural networks is presented. Lamb wave propagation within an aluminum plate has been modeled using explicit dynamic finite element method and verified by experimental works in literature. Having developed a reliable FEM model for lamb wave propagation, a piezoelectric actuator, eight piezoelectric sensors and a tiny groove as the crack, have been placed on the plate to produce and sense lamb waves. All sensors signals have been obtained and processed by new developed signal processing method, Hilbert Huang Transform, to find the first three peaks in their energy density spectrum. Having changed the location of the crack, numerous simulations have been done and sensor responses have been gathered to provide necessary amount of data for network training. These three peaks times have been used as the network inputs and region of the crack has been given to the network as the output. The plate has been divided to four regions and each region has been divided in four sub areas. ABAQUS FE software has been employed for modeling of the problem. A Radial Basis network has been trained successfully to find the region of the crack in the plate. Finding the region of the crack in the plate in the first step, it is possible to repeat the algorithm to find the sub area in which the crack located. The method has been verified by three test points for the crack and passed the test successfully.

关键词： Piezoelectricity

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Multi-sensor longitudinal control with fault tolerant guarantees 10

Multi-sensor longitudinal control with fault tolerant guaran...

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2009 10th European control Conference, ECC 2009

作者： Martinez, John J. Seron, Maria M. De Dona, Jose A. Département Automatique GIPSA-lab UMR 5216 Grenoble-INP France Centre for Complex Dynamic Systems and Control School of EEandCS University of Newcastle Australia CAS Mathématiques et Systèmes Mines-ParisTech France

ISBN: (纸本)9783952417393

This paper deals with the problem of obtaining fault-tolerant guarantees of a multi-sensor switching strategy for longitudinal control. The strategy selects, at each instant of time, the sensor (belonging to a collection of sensors) that provides the best closed loop performance, as measured by a control-performance criterion. It is assumed that each sensor has an associated feedback controller that has been designed such that the sensor-controller pair stabilises the closed loop system under normal operation conditions. Recent refinements for constructing ultimate-bound invariant sets allow obtaining less conservative fault-tolerant guarantees. Stability of the switching system under fault-free operation conditions and under presence of sensor failures are established in the main results of this paper. © 2009 EUCA.

关键词： Longitudinal control

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Invariant set approach to actuator fault tolerant control

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IFAC Proceedings Volumes 2009年第8期42卷 1605-1610页

作者： María M. Seron José A. De Doná John J. Martínez Centre for Complex Dynamic Systems and Control (CDSC) School of EE&CS The University of Newcastle Callaghan NSW 2308 Australia Gipsa-lab UMR 5216 Département Automatique. BP.46 St. Martin D'Hères 38440 France

We present a new actuator fault-tolerant control strategy based on the separation of sets that characterise healthy system operation from sets that characterise faulty operation. The new scheme is an extension of a similar strategy recently proposed by the authors. In the present paper we propose a new criterion for fault detection and isolation that leads to less conservative conditions for fault tolerant closed-loop stability. These new conditions employ discrete-time models for the plant, reference system and observers and allow for quicker fault detection and consequent reconfiguration of the controller.

关键词： Fault tolerant systems Actuators Observers Sets

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Multi-sensor longitudinal control with fault tolerant guarantees

Multi-sensor longitudinal control with fault tolerant guaran...

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European control Conference (ECC)

作者： John J. Martínez María M. Seron José A. De Doná Département Automatique GIPSA-lab UMR 5216 Grenoble-INP France Centre for Complex Dynamic Systems and Control School of EE&CS The University of Newcastle Australia CAS Mathématiques et Systèmes Mines-ParisTech France

关键词： Switches Fault tolerance Fault tolerant systems Vehicles Vehicle dynamics Trajectory

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A study of fuzzy hysteresis modeling and control of a shape emory wire actuator

A study of fuzzy hysteresis modeling and control of a shape ...

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21st Biennial Conference on Mechanical Vibration and Noise, presented at - 2007 ASME International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, IDETC/CIE2007

作者： Mehrabian, Ali Reza Hashemi, S. Vahid Williams, Eric Elahinia, Mohammad Advanced Dynamic and Control Systems Lab. School of Mechanical Engineering University of Tehran P.O.Box: 14875-347 Tehran Iran Dynamic and Smart Systems Laboratory University of Toledo Nitschke Hall 4045 OH 43606 United States

ISBN: (纸本)0791848027

This paper describes the development of fuzzy systems for modeling the hysteresis behavior of shape memory alloy (SMA) actuators. Due to their simplicity and ease of actuation, SMA actuators are very attractive for applications such as miniature robots for micro manufacturing. However, SMAs have not been widely used for motion control applications due to their nonlinear behavior and control difficulties. One approach to design a position controller for SMA systems is to employ an inverse-model of the system in the control loop to compensate the hysteresis properties of the material. Fuzzy systems, due to their nonlinear learning and adaptation abilities, are good candidates for obtaining inverse-models. In this paper two fuzzy modeling approaches are employed and compared to develop a model for a SMA wire actuator. A set of experiments are conducted to generate the training data. The test stand includes a Nickel-Titanium (TiNi) SMA wire, a position sensor, a bias spring and a current amplifier. By comparing the performance of the two employed fuzzy modeling techniques, it is revealed that the approach based on fuzzy Gustafson-Kessel (GK) clustering shows a better performance in the modeling of the hysteresis in the SMA wire. Thus, GK clustering algorithm is employed to develop the inverse-model for the SMA. The reported results demonstrate the ability of the employed fuzzy algorithm for modeling the hysteresis in the system, and the merits of the introduced inverse-model in the control of the position of the SMA. Copyright © 2007 by ASME.

关键词： Shape memory effect

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Fault-Tolerant Switching Scheme with Multiple Sensor-controller Pairs

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IFAC Proceedings Volumes 2008年第2期41卷 1212-1217页

作者： John J. Martínez María M. Seron José A. De Doná Gipsa-lab UMR 5216 Département Automatique. BP.46 St. Martin D'Hères 38440 France Centre for Complex Dynamic Systems and Control (CDSC) School of Electrical Engineering and Computer Science The University of Newcastle Callaghan NSW 2308 Australia

This paper deals with the problem of achieving high performance and fault tolerance properties of a given plant by switching between a collection of different sensor-controller pairs. We assume that each sensor-controller pair has been previously designed to achieve an appropriate performance objective according to disturbances, sensor noises, available bandwidth and uncertainties. The proposed strategy selects, at each instant of time, the sensor-controller pair that minimises a suitable switching criterion. Stability of the switching system under normal (fault-free) operation conditions is established in the main result of this paper. In addition, a simulation example of active suspension control illustrates that the proposed switching system is able to maintain performance levels, and to preserve stability under the occurrence of severe faults in some of the sensors.

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A genetic approach to anti-air missile control system design

A genetic approach to anti-air missile control system design

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作者： Mehrabian, Ali Reza Nayebpanah, Nastaran Advanced Dynamic and Control Systems Lab. School of Mechanical Engineering University of Tehran P.O.Box: 14875-347 Tehran Iran

ISBN: (纸本)9783902661241

Modern aircrafts and missiles with high manoeuvrability present an interesting challenge to autopilot design, which has activated new investigations in estimating the potential and applicability of recent theoretical control methods as well as how they can meet industrial demands. In this paper, a multi-objective approach for autopilot design is introduced. The design requirements are formulated using several integral criteria. A hybrid-genetic algorithm (GA) is employed to solve the nonlinear optimization problem. The obtained results are verified using nonlinear simulations in SIMULINK® which shows performance, stability and robustness of the designed flight controller. Copyright © 2007 IFAC.

关键词： Genetic algorithms

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Variable structure control of a ferromagnetic shape memory alloy actuator

Variable structure control of a ferromagnetic shape memory a...

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ASME 2007 International Mechanical Engineering Congress and Exposition, IMECE 2007

作者： Tan, Honghao Elahinia, Mohammad H. Electrical Integration and Control Lab General Motor NA Tech Center WarrenMI48092 United States Dynamic and Smart Systems Laboratory Department of Mechanical Industrial and Manufacturing Engineering University of Toledo ToledoOH43606 United States

ISBN: (纸本)0791843041

Ferromagnetic Shape Memory Alloys (FSMAs) like Ni-Mn-Ga have attracted significant attention over the last few years. As actuators, these materials offer high energy density, large stroke, and high bandwidth. These properties make FSMAs potential candidates for the new generation of actuators. The preliminary dynamic characterization of Ni-Mn-Ga illustrates nonlinear behaviors including hysteresis, saturation, first cycle effect, and dead zone. In this paper, the positioning control of a FSMA actuator is investigated. To this end, a dynamic model is presented for a Ni-Mn-Ga linear actuator. The actuator model consists of the following subsystems: a field-induced strain model of Ni-Mn-Ga, an elastic deformation model of the Ni-Mn-Ga element, a dynamics/kinematics model, and an electromagnetic dynamics model. The material damping effect is also included in the model by the Kelvin-Voigt model. A Proportional-Integral-Derivative (PID) position control algorithm is developed based on the model. Simulation result indicates poor performance of the PID controller. This is mainly due to nonlinearities in the actuator behavior. To address this problem, a variable structure controller is developed. Simulations with the variable structure controller show that this algorithm can improve the performance of the actuator with respect to rising time and positioning accuracy. Copyright © 2007 by ASME.

关键词： controllers

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A GENETIC APPROACH TO ANTI-AIR MISSILE control SYSTEM DESIGN

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IFAC Proceedings Volumes 2007年第7期40卷 61-66页

作者： Ali Reza Mehrabian Nastaran Nayebpanah Dynamic and Control Systems Lab. School of Mechanical Engineering University of Tehran Tehran Iran P.O.Box: 14875-347 Tehran Iran

关键词： Flight control Genetic algorithms PID controllers Nonlinear systems

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Sensitivity analysis for AC/DC hybrid power systems

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Dianli Xitong Zidonghua/Automation of Electric Power systems 2007年第12期31卷 45-49页

作者： Liu, Chongru Zhang, Boming Key Laboratory of Power System Protection and Dynamic Security Monitoring and Control North China Electric Power University Beijing 102206 China State Key Lab. of Power Systems Department of Electrical Engineering Tsinghua University Beijing 100084 China

The interactions between AC and DC systems in the steady-state condition of power systems are investigated. Through a sensitivity analysis, the influence of DC control parameters on the operation of AC/DC systems and that of AC control parameters on other AC parameters with the DC system existing are discussed. The sensitivity matrices and the influence factors between AC and DC systems are analyzed from various points of view. The sensitivity analysis made in this paper is expected to be of practical significance in such problems as load flow control, parameter regulation, voltage estimation, etc.

关键词： Electric power transmission networks

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