Two-Degrees of Freedom and Variable Structure Controllers for Induction Motor Drives

Directory of Open Access Journals (Sweden)

ZAKY, M.

2018-02-01

Full Text Available This paper presents a two-degrees-of-Freedom (2DOF and variable structure control (VSC schemes for induction motor (IM drives. The designed VSC incorporates independent feedback and feedforward terms as 2DOF control principle. This structure improves the response of the proposed VSC under speed reference tracking and load disturbance changes. Stability of VSC using Lyapunov theory is discussed. Due to the variable nature of the switching function of VSC, two conditions to ensure Lyapunov stability candidate are derived based on the error signal. A design criterion for the parameters of VSC are introduced to guarantee the stability. The complete IM drive system with the proposed VSC controller is built using MATLAB/Simulink. A laboratory prototype is executed experimentally using DSP-DS1104 control board. All controllers are implemented practically. Simulation and experimental results are provided under different working conditions. Performance evaluation of classic control schemes and the proposed VSC approach is presented. The proposed VSC approach gives superior behavior under speed reference variations and torque disturbances. The disturbances using the proposed controller are strongly suppressed compared to classic 2DOF control scheme.

Optimal control of large space structures via generalized inverse matrix

Science.gov (United States)

Nguyen, Charles C.; Fang, Xiaowen

1987-01-01

Independent Modal Space Control (IMSC) is a control scheme that decouples the space structure into n independent second-order subsystems according to n controlled modes and controls each mode independently. It is well-known that the IMSC eliminates control and observation spillover caused when the conventional coupled modal control scheme is employed. The independent control of each mode requires that the number of actuators be equal to the number of modelled modes, which is very high for a faithful modeling of large space structures. A control scheme is proposed that allows one to use a reduced number of actuators to control all modeled modes suboptimally. In particular, the method of generalized inverse matrices is employed to implement the actuators such that the eigenvalues of the closed-loop system are as closed as possible to those specified by the optimal IMSC. Computer simulation of the proposed control scheme on a simply supported beam is given.

Modal-space reference-model-tracking fuzzy control of earthquake excited structures

Science.gov (United States)

Park, Kwan-Soon; Ok, Seung-Yong

2015-01-01

This paper describes an adaptive modal-space reference-model-tracking fuzzy control technique for the vibration control of earthquake-excited structures. In the proposed approach, the fuzzy logic is introduced to update optimal control force so that the controlled structural response can track the desired response of a reference model. For easy and practical implementation, the reference model is constructed by assigning the target damping ratios to the first few dominant modes in modal space. The numerical simulation results demonstrate that the proposed approach successfully achieves not only the adaptive fault-tolerant control system against partial actuator failures but also the robust performance against the variations of the uncertain system properties by redistributing the feedback control forces to the available actuators.

Synchronization of chaotic systems with parameter uncertainties via variable structure control

International Nuclear Information System (INIS)

Etemadi, Shahram; Alasty, Aria; Salarieh, Hassan

2006-01-01

The Letter introduces a robust control design method to synchronize a pair of different uncertain chaotic systems. The technique is based on sliding-mode and variable structure control theories. Comparison of proposed method with previous works is performed during simulations. It is shown that the proposed controller while appearing in a faster response, is able to overcome random uncertainties of all model parameters

Synchronization of chaotic systems with parameter uncertainties via variable structure control

Energy Technology Data Exchange (ETDEWEB)

Etemadi, Shahram [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Alasty, Aria [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)]. E-mail: aalasti@sharif.edu; Salarieh, Hassan [Centre of Excellence in Design, Robotics and Automation (CEDRA), School of Mechanical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

2006-08-28

The Letter introduces a robust control design method to synchronize a pair of different uncertain chaotic systems. The technique is based on sliding-mode and variable structure control theories. Comparison of proposed method with previous works is performed during simulations. It is shown that the proposed controller while appearing in a faster response, is able to overcome random uncertainties of all model parameters.

Variable structure unit vector control of electric power generation ...

African Journals Online (AJOL)

A variable structure Automatic Generation Control (VSAGC) scheme is proposed in this paper for the control of a single area power system model dominated by steam powered electric generating plants. Unlike existing, VSAGC scheme where the selection of the control function is based on a trial and error procedure, the ...

Semi-decentralized Strategies in Structural Vibration Control

Directory of Open Access Journals (Sweden)

F. Palacios-Quiñonero

2011-04-01

Full Text Available In this work, the main ideas involved in the design of overlapping and multi-overlapping controllers via the Inclusion Principle are discussed and illustrated in the context of the Structural Vibration Control of tall buildings under seismic excitation. A detailed theoretical background on the Inclusion Principle and the design of overlapping controllers is provided. Overlapping and multi-overlapping LQR controllers are designed for a simplified five-story building model. Numerical simulations are conducted to asses the performance of the proposed semi-decentralized controllers with positive results.

Proposed Doctrine Based Structure of the Armored Reconnaissance Squadron

Science.gov (United States)

2017-06-09

squadron. A new structure was proposed based on the deduced required capabilities, utilizing organizational theory and current army practices. This...squadron, which now puts greater emphasis on this analysis to link structure to doctrinally based task. Organizational Theory Since earliest...expect to find capability based discourse; there is a lack of proposed structure based on capability, task or equipment . The Armour Bulletin serves

Formation control of unicycle robots using virtual structure approach

NARCIS (Netherlands)

Sadowska, A.D.; Huijberts, H.J.C.; Kostic, D.; Wouw, van de N.; Nijmeijer, H.

2011-01-01

This paper addresses the problem of formation control of groups of unicycle robots with possibly time-varying formation shapes. To solve the problem, we propose two simple distributed formation control algorithms based on the virtual structure approach. We prove exponential convergence of error

Application of Transfer Matrix Approach to Modeling and Decentralized Control of Lattice-Based Structures

Science.gov (United States)

Cramer, Nick; Swei, Sean Shan-Min; Cheung, Kenny; Teodorescu, Mircea

2015-01-01

This paper presents a modeling and control of aerostructure developed by lattice-based cellular materials/components. The proposed aerostructure concept leverages a building block strategy for lattice-based components which provide great adaptability to varying ight scenarios, the needs of which are essential for in- ight wing shaping control. A decentralized structural control design is proposed that utilizes discrete-time lumped mass transfer matrix method (DT-LM-TMM). The objective is to develop an e ective reduced order model through DT-LM-TMM that can be used to design a decentralized controller for the structural control of a wing. The proposed approach developed in this paper shows that, as far as the performance of overall structural system is concerned, the reduced order model can be as e ective as the full order model in designing an optimal stabilizing controller.

Passive Control of Flexible Structures by Confinement of Vibrations

Directory of Open Access Journals (Sweden)

M. Ouled Chtiba

2007-01-01

Full Text Available We propose a two-step strategy for the design of passive controllers for the simultaneous confinement and suppression of vibrations (SCSV in mechanical structures. Once the sensitive and insensitive elements of these structures are identified, the first design step synthesizes an active control law, which is referred to as the reference control law (RCL, for the SCSV. We show that the problem of SCSV can be formulated as an LQR-optimal control problem through which the maximum amplitudes, associated with the control input and the displacements of the sensitive and insensitive parts, can be regulated. In the second design step, a transformation technique that yields an equivalent passive controller is used. Such a technique uses the square root of sum of squares method to approximate an equivalent passive controller while maximizing the effects of springs and dampers characterizing passive elements that are added to the original structure. The viability of the proposed control design is illustrated using a three-DOF mechanical system subject to an excitation. It is assumed that all of the masses are sensitive to the excitation, and thus the vibratory energy must be confined in the added passive elements (insensitive parts. We show that the vibration amplitudes associated with the sensitive masses are attenuated at fast rate at the expense of slowing down the convergence of the passive elements to their steady states. It is also demonstrated that a combination of the RCL and the equivalent passive control strategy leads to similar structural performance.

Definition of the topological structure of the automatic control system of spacecrafts

International Nuclear Information System (INIS)

KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F.Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Zelenkov, P V; KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F.Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Karaseva, M V; KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" data-affiliation=" (Siberian State Aerospace University named after Academician M.F.Reshetnev 31 KrasnoyarskiyRabochiy prospect, Krasnoyarsk, 660014 (Russian Federation))" >Tsareva, E A; Tsarev, R Y

2015-01-01

The paper considers the problem of selection the topological structure of the automated control system of spacecrafts. The integer linear model of mathematical programming designed to define the optimal topological structure for spacecraft control is proposed. To solve the determination problem of topological structure of the control system of spacecrafts developed the procedure of the directed search of some structure variants according to the scheme 'Branch and bound'. The example of the automated control system of spacecraft development included the combination of ground control stations, managing the spacecraft of three classes with a geosynchronous orbit with constant orbital periods is presented

A microgrid cluster structure and its autonomous coordination control strategy

DEFF Research Database (Denmark)

Zhou, Xiaoping; Zhou, Leming; Chen, Yandong

2018-01-01

This paper proposes a microgrid cluster structure and its autonomous coordination control strategy. Unlike existing microgrids that are purely AC or DC, the microgrid cluster studied here is an interconnected system with multiple AC and DC microgrids, which enables mutual power support among...... control method combining the normalized droop-based control and adaptive control is proposed for PEU, which can effectively realize mutual power support among microgrids and reduce the bus voltage or frequency deviation in microgrids. In addition, the adaptive control strategy of PEU can ensure...... that the bigger the normalized index of microgrid is, the larger the active power exchange coefficient is, which can make all of microgrids operate around the rated state as much as possible. Besides, EP is mainly used to balance the system power, and the hierarchical coordinated control method of EP is proposed...

Active queue management controller design for TCP communication networks: Variable structure control approach

International Nuclear Information System (INIS)

Chen, C.-K.; Liao, T.-L.; Yan, J.-J.

2009-01-01

On the basis of variable structure control (VSC), an active queue management (AQM) controller is presented for a class of TCP communication networks. In the TCP/IP networks, the packet drop probability is limited between 0 and 1. Therefore, we modeled TCP/AQM as a rate-based non-linear system with a saturated input. The objective of the VSC-based AQM controller is to achieve the desired queue size and to guarantee the asymptotic stability of the closed-loop TCP non-linear system with saturated input. The performance and effectiveness of the proposed control law are then validated for different network scenarios through numerical simulations in both MATLAB and Network Simulator-2 (NS-2). Both sets of simulation results have confirmed that the proposed scheme outperforms other AQM schemes.

Active queue management controller design for TCP communication networks: Variable structure control approach

Energy Technology Data Exchange (ETDEWEB)

Chen, C.-K. [Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China); Liao, T.-L. [Department of Engineering Science, National Cheng Kung University, Tainan 701, Taiwan (China)], E-mail: tlliao@mail.ncku.edu; Yan, J.-J. [Department of Computer and Communication, Shu-Te University, Kaohsiung 824, Taiwan (China)

2009-04-15

On the basis of variable structure control (VSC), an active queue management (AQM) controller is presented for a class of TCP communication networks. In the TCP/IP networks, the packet drop probability is limited between 0 and 1. Therefore, we modeled TCP/AQM as a rate-based non-linear system with a saturated input. The objective of the VSC-based AQM controller is to achieve the desired queue size and to guarantee the asymptotic stability of the closed-loop TCP non-linear system with saturated input. The performance and effectiveness of the proposed control law are then validated for different network scenarios through numerical simulations in both MATLAB and Network Simulator-2 (NS-2). Both sets of simulation results have confirmed that the proposed scheme outperforms other AQM schemes.

Some principles of automated control systems construction with project organizational structure

OpenAIRE

Kovalenko, Ihor I.; Puhachenko, Kateryna S.

2013-01-01

The main principles of automated control systems construction with project organizational structures have been considered and the process flow sheet  for organizational systems control has been proposed. The architectural elements of the organizational system have been introduced and described. The instrumental tools of the graphodynamic systems theory have been used for the simulation modeling of hierarchical structures.

Active structural control with stable fuzzy PID techniques

CERN Document Server

Yu, Wen

2016-01-01

This book presents a detailed discussion of intelligent techniques to measure the displacement of buildings when they are subjected to vibration. It shows how these techniques are used to control active devices that can reduce vibration 60–80% more effectively than widely used passive anti-seismic systems. After introducing various structural control devices and building-modeling and active structural control methods, the authors propose offset cancellation and high-pass filtering techniques to solve some common problems of building-displacement measurement using accelerometers. The most popular control algorithms in industrial settings, PD/PID controllers, are then analyzed and then combined with fuzzy compensation. The stability of this combination is proven with standard weight-training algorithms. These conditions provide explicit methods for selecting PD/PID controllers. Finally, fuzzy-logic and sliding-mode control are applied to the control of wind-induced vibration. The methods described are support...

Fracture mechanisms and fracture control in composite structures

Science.gov (United States)

Kim, Wone-Chul

Four basic failure modes--delamination, delamination buckling of composite sandwich panels, first-ply failure in cross-ply laminates, and compression failure--are analyzed using linear elastic fracture mechanics (LEFM) and the J-integral method. Structural failures, including those at the micromechanical level, are investigated with the aid of the models developed, and the critical strains for crack propagation for each mode are obtained. In the structural fracture analyses area, the fracture control schemes for delamination in a composite rib stiffener and delamination buckling in composite sandwich panels subjected to in-plane compression are determined. The critical fracture strains were predicted with the aid of LEFM for delamination and the J-integral method for delamination buckling. The use of toughened matrix systems has been recommended for improved damage tolerant design for delamination crack propagation. An experimental study was conducted to determine the onset of delamination buckling in composite sandwich panel containing flaws. The critical fracture loads computed using the proposed theoretical model and a numerical computational scheme closely followed the experimental measurements made on sandwich panel specimens of graphite/epoxy faceskins and aluminum honeycomb core with varying faceskin thicknesses and core sizes. Micromechanical models of fracture in composites are explored to predict transverse cracking of cross-ply laminates and compression fracture of unidirectional composites. A modified shear lag model which takes into account the important role of interlaminar shear zones between the 0 degree and 90 degree piles in cross-ply laminate is proposed and criteria for transverse cracking have been developed. For compressive failure of unidirectional composites, pre-existing defects play an important role. Using anisotropic elasticity, the stress state around a defect under a remotely applied compressive load is obtained. The experimentally

Nonlinear Control Structure of Grid Connected Modular Multilevel Converters

DEFF Research Database (Denmark)

Hajizadeh, Amin; Norum, Lars; Ahadpour Shal, Alireza

2017-01-01

in the prediction step in order to preserve the stochastic characteristics of a nonlinear system. In order to design adaptive robust control strategy and nonlinear observer, mathematical model of MMC using rotating d-q theory has been used. Digital time-domain simulation studies are carried out in the Matlab......This paper implements nonlinear control structure based on Adaptive Fuzzy Sliding Mode (AFSM) Current Control and Unscented Kalman Filter (UKF) to estimate the capacitor voltages from the measurement of arm currents of Modular Multilevel Converter (MMC). UKF use nonlinear unscented transforms....../Simulink environment to verify the performance of the overall proposed control structure during different case studies....

Proposed Food (Control of Irradiation) Regulations 1990

International Nuclear Information System (INIS)

1990-08-01

The paper summarizes proposals UK Ministry of Agriculture, Fisheries and Food Proposals for part of a comprehensive range of controls applying to premises using sources of ionising radiation in the processing of food. (UK)

Chaos control and generalized projective synchronization of heavy symmetric chaotic gyroscope systems via Gaussian radial basis adaptive variable structure control

International Nuclear Information System (INIS)

Farivar, Faezeh; Aliyari Shoorehdeli, Mahdi; Nekoui, Mohammad Ali; Teshnehlab, Mohammad

2012-01-01

Highlights: ► A systematic procedure for GPS of unknown heavy chaotic gyroscope systems. ► Proposed methods are based on Lyapunov stability theory. ► Without calculating Lyapunov exponents and Eigen values of the Jacobian matrix. ► Capable to extend for a variety of chaotic systems. ► Useful for practical applications in the future. - Abstract: This paper proposes the chaos control and the generalized projective synchronization methods for heavy symmetric gyroscope systems via Gaussian radial basis adaptive variable structure control. Because of the nonlinear terms of the gyroscope system, the system exhibits chaotic motions. Occasionally, the extreme sensitivity to initial states in a system operating in chaotic mode can be very destructive to the system because of unpredictable behavior. In order to improve the performance of a dynamic system or avoid the chaotic phenomena, it is necessary to control a chaotic system with a periodic motion beneficial for working with a particular condition. As chaotic signals are usually broadband and noise like, synchronized chaotic systems can be used as cipher generators for secure communication. This paper presents chaos synchronization of two identical chaotic motions of symmetric gyroscopes. In this paper, the switching surfaces are adopted to ensure the stability of the error dynamics in variable structure control. Using the neural variable structure control technique, control laws are established which guarantees the chaos control and the generalized projective synchronization of unknown gyroscope systems. In the neural variable structure control, Gaussian radial basis functions are utilized to on-line estimate the system dynamic functions. Also, the adaptation laws of the on-line estimator are derived in the sense of Lyapunov function. Thus, the unknown gyro systems can be guaranteed to be asymptotically stable. Also, the proposed method can achieve the control objectives. Numerical simulations are presented to

Synthesis of vibration control and health monitoring of building structures under unknown excitation

International Nuclear Information System (INIS)

He, Jia; Huang, Qin; Xu, You-Lin

2014-01-01

The vibration control and health monitoring of building structures have been actively investigated in recent years but often treated separately according to the primary objective pursued. In this study, a time-domain integrated vibration control and health monitoring approach is proposed based on the extended Kalman filter (EKF) for identifying the physical parameters of the controlled building structures without the knowledge of the external excitation. The physical parameters and state vectors of the building structure are then estimated and used for the determination of the control force for the purpose of the vibration attenuation. The interaction between the health monitoring and vibration control is revealed and assessed. The feasibility and reliability of the proposed approach is numerically demonstrated via a five-story shear building structure equipped with magneto-rheological (MR) dampers. Two types of excitations are considered: (1) the EI-Centro ground excitation underneath of the building and (2) a swept-frequency excitation applied on the top floor of the building. Results show that the structural parameters as well as the unknown dynamic loadings could be identified accurately; and, at the same time, the structural vibration is significantly reduced in the building structure. (paper)

Active Power Filter DC Bus Voltage Piecewise Reaching Law Variable Structure Control

Directory of Open Access Journals (Sweden)

Baolian Liu

2014-01-01

Full Text Available The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the above problem, and the design method is given. The simulation and experiment results proved that the proposed variable structure control algorithm can eliminate the chattering problem existing in traditional variable structure control effectively, is insensitive to system disturbance, and has good robustness and fast dynamic response speed and stable DC bus voltage with small fluctuation. The above advantages ensure the compensation effect of APF.

Soft Time-Suboptimal Controlling Structure for Mechanical Systems

DEFF Research Database (Denmark)

Kulczycki, Piotr; Wisniewski, Rafal; Kowalski, Piotr

2004-01-01

The paper presents conception of a soft control structure based on the time-optimal approach. Its parameters are selected in accordance with the rules of the statistical decision theory and additionally it allows to eliminate rapid changes in control values. The object is a basic mechanical system......, with uncertain (also non-stationary) mass treated as a stochastic process. The methodology proposed here is of a universal nature and may easily be applied with respect to other uncertainty elements of timeoptimal controlled mechanical systems....

Reduction of Flight Control System/Structural Mode Interaction, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A novel approach is proposed for reducing the degree of interaction of a high gain flight control system with the airframe structural vibration modes, representing a...

Virtual sensors for active noise control in acoustic-structural coupled enclosures using structural sensing: robust virtual sensor design.

Science.gov (United States)

Halim, Dunant; Cheng, Li; Su, Zhongqing

2011-03-01

The work was aimed to develop a robust virtual sensing design methodology for sensing and active control applications of vibro-acoustic systems. The proposed virtual sensor was designed to estimate a broadband acoustic interior sound pressure using structural sensors, with robustness against certain dynamic uncertainties occurring in an acoustic-structural coupled enclosure. A convex combination of Kalman sub-filters was used during the design, accommodating different sets of perturbed dynamic model of the vibro-acoustic enclosure. A minimax optimization problem was set up to determine an optimal convex combination of Kalman sub-filters, ensuring an optimal worst-case virtual sensing performance. The virtual sensing and active noise control performance was numerically investigated on a rectangular panel-cavity system. It was demonstrated that the proposed virtual sensor could accurately estimate the interior sound pressure, particularly the one dominated by cavity-controlled modes, by using a structural sensor. With such a virtual sensing technique, effective active noise control performance was also obtained even for the worst-case dynamics. © 2011 Acoustical Society of America

Adaptive Functional-Based Neuro-Fuzzy-PID Incremental Controller Structure

Directory of Open Access Journals (Sweden)

Ashraf Ahmed Fahmy

2014-03-01

Full Text Available This paper presents an adaptive functional-based Neuro-fuzzy-PID incremental (NFPID controller structure that can be tuned either offline or online according to required controller performance. First, differential membership functions are used to represent the fuzzy membership functions of the input-output space of the three term controller. Second, controller rules are generated based on the discrete proportional, derivative, and integral function for the fuzzy space. Finally, a fully differentiable fuzzy neural network is constructed to represent the developed controller for either offline or online controller parameter adaptation.  Two different adaptation methods are used for controller tuning, offline method based on controller transient performance cost function optimization using Bees Algorithm, and online method based on tracking error minimization using back-propagation with momentum algorithm. The proposed control system was tested to show the validity of the controller structure over a fixed PID controller gains to control SCARA type robot arm.

Tunable Bandgap Opening in the Proposed Structure of Silicon Doped Graphene

OpenAIRE

Azadeh, Mohammad S. Sharif; Kokabi, Alireza; Hosseini, Mehdi; Fardmanesh, Mehdi

2011-01-01

A specific structure of doped graphene with substituted silicon impurity is introduced and ab. initio density-functional approach is applied for energy band structure calculation of proposed structure. Using the band structure calculation for different silicon sites in the host graphene, the effect of silicon concentration and unit cell geometry on the bandgap of the proposed structure is also investigated. Chemically silicon doped graphene results in an energy gap as large as 2eV according t...

Structured, Gain-Scheduled Control of Wind Turbines

DEFF Research Database (Denmark)

Adegas, Fabiano Daher

2013-01-01

Improvements in cost-effectiveness and reliability of wind turbines is a constant in the industry. This requires new knowledge and systematic methods for analyzing and designing the interaction of structural dynamics, aerodynamics, and controllers. This thesis presents novel methods and theoretical....... Robustness and fault-tolerance capabilities are also important properties, which should be considered in the design process. Novel gain-scheduling and robust control methods that adapt to variations in the operational conditions of the wind turbine are proposed under the linear parameter-varying (LPV...... intuitive and physical specifications for vibration control, such as minimum damping and decay rate of aeroelastic modes. Moreover, the number of weighting functions and consequently the order of the final controller is reduced. Inspired by this application, theoretical control developments are presented...

Active control of flexible structures using a fuzzy logic algorithm

Science.gov (United States)

Cohen, Kelly; Weller, Tanchum; Ben-Asher, Joseph Z.

2002-08-01

This study deals with the development and application of an active control law for the vibration suppression of beam-like flexible structures experiencing transient disturbances. Collocated pairs of sensors/actuators provide active control of the structure. A design methodology for the closed-loop control algorithm based on fuzzy logic is proposed. First, the behavior of the open-loop system is observed. Then, the number and locations of collocated actuator/sensor pairs are selected. The proposed control law, which is based on the principles of passivity, commands the actuator to emulate the behavior of a dynamic vibration absorber. The absorber is tuned to a targeted frequency, whereas the damping coefficient of the dashpot is varied in a closed loop using a fuzzy logic based algorithm. This approach not only ensures inherent stability associated with passive absorbers, but also circumvents the phenomenon of modal spillover. The developed controller is applied to the AFWAL/FIB 10 bar truss. Simulated results using MATLAB© show that the closed-loop system exhibits fairly quick settling times and desirable performance, as well as robustness characteristics. To demonstrate the robustness of the control system to changes in the temporal dynamics of the flexible structure, the transient response to a considerably perturbed plant is simulated. The modal frequencies of the 10 bar truss were raised as well as lowered substantially, thereby significantly perturbing the natural frequencies of vibration. For these cases, too, the developed control law provides adequate settling times and rates of vibrational energy dissipation.

Simultaneous Structural Health Monitoring and Vibration Control of Adaptive Structures Using Smart Materials

Directory of Open Access Journals (Sweden)

Myung-Hyun Kim

2002-01-01

Full Text Available The integration of actuators and sensors using smart materials enabled various applications including health monitoring and structural vibration control. In this study, a robust control technique is designed and implemented in order to reduce vibration of an active structure. Special attention is given to eliminating the possibility of interaction between the health monitoring system and the control system. Exploiting the disturbance decoupling characteristic of the sliding mode observer, it is demonstrated that the proposed observer can eliminate the possible high frequency excitation from the health monitoring system. At the same time, a damage identification scheme, which tracks the changes of mechanical impedance due to the presence of damage, has been applied to assess the health condition of structures. The main objective of this paper is to examine the potential of combining the two emerging techniques together. Using the collocated piezoelectric sensors/actuators for vibration suppression as well as for health monitoring, this technique enabled to reduce the number of system components, while enhancing the performance of structures. As an initial study, both simulation and experimental investigations were performed for an active beam structure. The results show that this integrated technique can provide substantial vibration reductions, while detecting damage on the structure at the same time.

EPA proposes options for control of industrial radioactivity

International Nuclear Information System (INIS)

Anon.

1989-01-01

The US Environmental Protection Agency on February 28 proposed four alternative approaches for controlling radionuclides from a dozen industrial sources. The proposal outlines four alternatives for regulating toxic air pollutant. The proposal is designed to elicit comment on such regulatory issues as: What are acceptable health risks? What are appropriate criteria for establishing a margin of safety? What are the technological feasibility and the costs of regulatory controls? How should uncertainty by considered? EPA intends to use the approach finally selected as the framework for future hazardous-air pollutant-control decisions. Industry uses hundreds of distinct radionuclides in solid, liquid and gaseous forms. Industrial radionuclide emissions occur either as a result of an inability to contain the radioactive materials or as an unintended consequence of other activity, such as radionuclide emissions from mining or milling

Fractional order PID control design for semi-active control of smart base-isolated structures: A multi-objective cuckoo search approach.

Science.gov (United States)

Zamani, Abbas-Ali; Tavakoli, Saeed; Etedali, Sadegh

2017-03-01

Fractional order PID (FOPID) controllers are introduced as a general form of classical PID controllers using fractional calculus. As this controller provides good disturbance rejection and is robust against plant uncertainties it is appropriate for the vibration mitigation in structures. In this paper, an FOPID controller is designed to adjust the contact force of piezoelectric friction dampers for semi-active control of base-isolated structures during far-field and near-field earthquake excitations. A multi-objective cuckoo search algorithm is employed to tune the controller parameters. Considering the resulting Pareto optimal front, the best input for the FOPID controller is selected. For seven pairs of earthquakes and nine performance indices, the performance of the proposed controller is compared with those provided by several well-known control techniques. According to the simulation results, the proposed controller performs better than other controllers in terms of simultaneous reduction of the maximum base displacement and story acceleration for various types of earthquakes. Also, it provides acceptable responses in terms of inter-story drifts, root mean square of base displacements and floor acceleration. In addition, the evaluation of robustness for a stiffness uncertainty of ±10% indicates that the proposed controller gives a robust performance against such modeling errors. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Delayed Antiwindup Control Using a Decoupling Structure

Directory of Open Access Journals (Sweden)

Huawei Zhu

2013-01-01

Full Text Available This paper investigates the antiwindup (AW control problem for plants with input saturation. The AW compensator is not activated as soon as input saturation occurs as usual. A delayed decoupling structure is first proposed. Then, appropriate linear matrix inequalities (LMIs are developed to determine a plant-order AW compensator. Effectiveness of the presented AW technique is illustrated by a fighter aircraft model.

Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies

International Nuclear Information System (INIS)

Xie Faxiang; Sun Limin

2010-01-01

The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

Passive Vibration Control of Existing Structures by Gravity-Loaded Cables

Science.gov (United States)

Alvis, E.; Tsang, H. H.; Hashemi, M. J.

2017-06-01

Structures with high concentration of mass at or close to the top such as highway bridge piers are vulnerable in earthquakes or accidents. In this paper, a simple and convenient retrofit strategy is proposed for minimizing vibrations and damages, extending service life and preventing collapse of existing structures. The proposed system comprises of tension-only cables secured to the sides of the structure through gravity anchor blocks that are free to move in vertical shafts. The system is installed in such a way that the cables do not induce unnecessary stress on the main structure when there is no lateral motion or vibration. The effectiveness of controlling global structural responses is investigated for tension-only bilinear-elastic behaviour of cables. Results of a realistic case study for a reinforced concrete bridge pier show that response reduction is remarkably well under seismic excitation.

Adaptive Sliding Mode Control of Dynamic Systems Using Double Loop Recurrent Neural Network Structure.

Science.gov (United States)

Fei, Juntao; Lu, Cheng

2018-04-01

In this paper, an adaptive sliding mode control system using a double loop recurrent neural network (DLRNN) structure is proposed for a class of nonlinear dynamic systems. A new three-layer RNN is proposed to approximate unknown dynamics with two different kinds of feedback loops where the firing weights and output signal calculated in the last step are stored and used as the feedback signals in each feedback loop. Since the new structure has combined the advantages of internal feedback NN and external feedback NN, it can acquire the internal state information while the output signal is also captured, thus the new designed DLRNN can achieve better approximation performance compared with the regular NNs without feedback loops or the regular RNNs with a single feedback loop. The new proposed DLRNN structure is employed in an equivalent controller to approximate the unknown nonlinear system dynamics, and the parameters of the DLRNN are updated online by adaptive laws to get favorable approximation performance. To investigate the effectiveness of the proposed controller, the designed adaptive sliding mode controller with the DLRNN is applied to a -axis microelectromechanical system gyroscope to control the vibrating dynamics of the proof mass. Simulation results demonstrate that the proposed methodology can achieve good tracking property, and the comparisons of the approximation performance between radial basis function NN, RNN, and DLRNN show that the DLRNN can accurately estimate the unknown dynamics with a fast speed while the internal states of DLRNN are more stable.

77 FR 11136 - Proposed Collection; Comment Request; a Multi-Center International Hospital-Based Case-Control...

Science.gov (United States)

2012-02-24

... proposed projects to be submitted to the Office of Management and Budget (OMB) for review and approval... conclusively established and the identification of the key, functional alleles in gene regions associated with... underlying genetic structure. A multidisciplinary case- control study of lymphoma in Asia, where lymphoma...

Proposal of Wireless Traffic Control Schemes for Wireless LANs

Science.gov (United States)

Hiraguri, Takefumi; Ichikawa, Takeo; Iizuka, Masataka; Kubota, Shuji

This paper proposes two traffic control schemes to support the communication quality of multimedia streaming services such as VoIP and audio/video over IEEE 802.11 wireless LAN systems. The main features of the proposed scheme are bandwidth control for each flow of the multimedia streaming service and load balancing between access points (APs) of the wireless LAN by using information of data link, network and transport layers. The proposed schemes are implemented on a Linux machine which is called the wireless traffic controller (WTC). The WTC connects a high capacity backbone network and an access network to which the APs are attached. We evaluated the performance of the proposed WTC and confirmed that the communication quality of the multimedia streaming would be greatly improved by using this technique.

Improving substructure identification accuracy of shear structures using virtual control system

Science.gov (United States)

Zhang, Dongyu; Yang, Yang; Wang, Tingqiang; Li, Hui

2018-02-01

Substructure identification is a powerful tool to identify the parameters of a complex structure. Previously, the authors developed an inductive substructure identification method for shear structures. The identification error analysis showed that the identification accuracy of this method is significantly influenced by the magnitudes of two key structural responses near a certain frequency; if these responses are unfavorable, the method cannot provide accurate estimation results. In this paper, a novel method is proposed to improve the substructure identification accuracy by introducing a virtual control system (VCS) into the structure. A virtual control system is a self-balanced system, which consists of some control devices and a set of self-balanced forces. The self-balanced forces counterbalance the forces that the control devices apply on the structure. The control devices are combined with the structure to form a controlled structure used to replace the original structure in the substructure identification; and the self-balance forces are treated as known external excitations to the controlled structure. By optimally tuning the VCS’s parameters, the dynamic characteristics of the controlled structure can be changed such that the original structural responses become more favorable for the substructure identification and, thus, the identification accuracy is improved. A numerical example of 6-story shear structure is utilized to verify the effectiveness of the VCS based controlled substructure identification method. Finally, shake table tests are conducted on a 3-story structural model to verify the efficacy of the VCS to enhance the identification accuracy of the structural parameters.

Structural monitoring and smart control of a wind turbine

DEFF Research Database (Denmark)

Caterino, Nicola; Trinchillo, Francesco; Georgakis, Christos T.

2014-01-01

The remarkable growth in height of wind turbines in the last years - for a higher production of electricity - makes the issues of monitoring and control of such challenging engineering works pressing than ever. The research herein proposed is addressed to monitor the structural demand imposed to ...

Passive and Active Vibration Control of Renewable Energy Structures

DEFF Research Database (Denmark)

Zhang, Zili

The present thesis deals with fundamental researches on passive and active vibration control of renewable energy structures, and provides useful models for practical applications. Effective and robust vibration control methods have been explored for mitigating the lightly damped edgewise blade...... solutions for wave energy point absorbers, in order to maximize the mean absorbed power and to deliver more smooth power to the grid. A novel suboptimal causal control law has been established for controlling the motion of the point absorber, and a new type of point absorber has also been proposed...

Self-Learning Variable Structure Control for a Class of Sensor-Actuator Systems

Science.gov (United States)

Chen, Sanfeng; Li, Shuai; Liu, Bo; Lou, Yuesheng; Liang, Yongsheng

2012-01-01

Variable structure strategy is widely used for the control of sensor-actuator systems modeled by Euler-Lagrange equations. However, accurate knowledge on the model structure and model parameters are often required for the control design. In this paper, we consider model-free variable structure control of a class of sensor-actuator systems, where only the online input and output of the system are available while the mathematic model of the system is unknown. The problem is formulated from an optimal control perspective and the implicit form of the control law are analytically obtained by using the principle of optimality. The control law and the optimal cost function are explicitly solved iteratively. Simulations demonstrate the effectiveness and the efficiency of the proposed method. PMID:22778633

Proposed general amendments to the atomic energy control regulations

International Nuclear Information System (INIS)

1986-01-01

Canada's Atomic Energy Control Act defines the powers and responsibilities of the Atomic Energy Control Board (AECB). Among these is to make regulations to control the development, application and use of atomic energy. In these proposed general amendments to the Atomic Energy Control Regulations substantial changes are proposed in the designation of the authority of AECB staff, exemptions from licensing, international safeguards, duties of licensees and atomic radiation workers, security of information, and provision for hearings. The scope of the control of atomic energy has been redefined as relating to matters of health, safety, security, international safeguards, and the protection of the environment

Pole placement algorithm for control of civil structures subjected to earthquake excitation

Directory of Open Access Journals (Sweden)

Nikos Pnevmatikos

2017-04-01

Full Text Available In this paper the control algorithm for controlled civil structures subjected to earthquake excitation is thoroughly investigated. The objective of this work is the control of structures by means of the pole placement algorithm, in order to improve their response against earthquake actions. Successful application of the algorithm requires judicious placement of the closed-loop eigenvalues from the part of the designer. The pole placement algorithm was widely applied to control mechanical systems. In this paper, a modification in the mathematical background of the algorithm in order to be suitable for civil fixed structures is primarily presented. The proposed approach is demonstrated by numerical simulations for the control of both single and multi-degree of freedom systems subjected to seismic actions. Numerical results have shown that the control algorithm is efficient in reducing the response of building structures, with small amount of required control forces.

Negative derivative feedback for vibration control of flexible structures

International Nuclear Information System (INIS)

Cazzulani, G; Resta, F; Ripamonti, F; Zanzi, R

2012-01-01

In this paper a resonant control technique, called negative derivative feedback (NDF), for structural vibration control is presented. Resonant control is a class of control logics, based on the modal approach, which calculates the control action through a dynamic compensator in order to achieve a damping increase on a certain number of system modes. The NDF compensator is designed to work as a band-pass filter, cutting off the control action far from the natural frequencies associated with the controlled modes and reducing the so-called spillover effect. In the paper the proposed control logic is compared both theoretically and experimentally with the most common state-of-the-art resonant control techniques. (paper)

Energy consumption control automation using Artificial Neural Networks and adaptive algorithms: Proposal of a new methodology and case study

International Nuclear Information System (INIS)

Benedetti, Miriam; Cesarotti, Vittorio; Introna, Vito; Serranti, Jacopo

2016-01-01

Highlights: • A methodology to enable energy consumption control automation is proposed. • The methodology is based on the use of Artificial Neural Networks. • A method to control the accuracy of the model over time is proposed. • Two methods to enable automatic retraining of the network are proposed. • Retraining methods are evaluated on their accuracy over time. - Abstract: Energy consumption control in energy intensive companies is always more considered as a critical activity to continuously improve energy performance. It undoubtedly requires a huge effort in data gathering and analysis, and the amount of these data together with the scarceness of human resources devoted to Energy Management activities who could maintain and update the analyses’ output are often the main barriers to its diffusion in companies. Advanced tools such as software based on machine learning techniques are therefore the key to overcome these barriers and allow an easy but accurate control. This type of systems is able to solve complex problems obtaining reliable results over time, but not to understand when the reliability of the results is declining (a common situation considering energy using systems, often undergoing structural changes) and to automatically adapt itself using a limited amount of training data, so that a completely automatic application is not yet available and the automatic energy consumption control using intelligent systems is still a challenge. This paper presents a whole new approach to energy consumption control, proposing a methodology based on Artificial Neural Networks (ANNs) and aimed at creating an automatic energy consumption control system. First of all, three different structures of neural networks are proposed and trained using a huge amount of data. Three different performance indicators are then used to identify the most suitable structure, which is implemented to create an energy consumption control tool. In addition, considering that

FRF-based structural damage detection of controlled buildings with podium structures: Experimental investigation

Science.gov (United States)

Xu, Y. L.; Huang, Q.; Zhan, S.; Su, Z. Q.; Liu, H. J.

2014-06-01

How to use control devices to enhance system identification and damage detection in relation to a structure that requires both vibration control and structural health monitoring is an interesting yet practical topic. In this study, the possibility of using the added stiffness provided by control devices and frequency response functions (FRFs) to detect damage in a building complex was explored experimentally. Scale models of a 12-storey main building and a 3-storey podium structure were built to represent a building complex. Given that the connection between the main building and the podium structure is most susceptible to damage, damage to the building complex was experimentally simulated by changing the connection stiffness. To simulate the added stiffness provided by a semi-active friction damper, a steel circular ring was designed and used to add the related stiffness to the building complex. By varying the connection stiffness using an eccentric wheel excitation system and by adding or not adding the circular ring, eight cases were investigated and eight sets of FRFs were measured. The experimental results were used to detect damage (changes in connection stiffness) using a recently proposed FRF-based damage detection method. The experimental results showed that the FRF-based damage detection method could satisfactorily locate and quantify damage.

Fault Tolerant Control for Civil Structures Based on LMI Approach

Directory of Open Access Journals (Sweden)

Chunxu Qu

2013-01-01

Full Text Available The control system may lose the performance to suppress the structural vibration due to the faults in sensors or actuators. This paper designs the filter to perform the fault detection and isolation (FDI and then reforms the control strategy to achieve the fault tolerant control (FTC. The dynamic equation of the structure with active mass damper (AMD is first formulated. Then, an estimated system is built to transform the FDI filter design problem to the static gain optimization problem. The gain is designed to minimize the gap between the estimated system and the practical system, which can be calculated by linear matrix inequality (LMI approach. The FDI filter is finally used to isolate the sensor faults and reform the FTC strategy. The efficiency of FDI and FTC is validated by the numerical simulation of a three-story structure with AMD system with the consideration of sensor faults. The results show that the proposed FDI filter can detect the sensor faults and FTC controller can effectively tolerate the faults and suppress the structural vibration.

Development of magnetostrictive active members for control of space structures

Science.gov (United States)

Johnson, Bruce G.; Avakian, Kevin M.; Fenn, Ralph C.; Gaffney, Monique S.; Gerver, Michael J.; Hawkey, Timothy J.; Boudreau, Donald J.

1992-08-01

The goal of this Phase 2 Small Business Innovative Research (SBIR) project was to determine the technical feasibility of developing magnetostrictive active members for use as truss elements in space structures. Active members control elastic vibrations of truss-based space structures and integrate the functions of truss structure element, actively controlled actuator, and sensor. The active members must control structural motion to the sub-micron level and, for many proposed space applications, work at cryogenic temperatures. Under this program both room temperature and cryogenic temperature magnetostrictive active members were designed, fabricated, and tested. The results of these performance tests indicated that room temperature magnetostrictive actuators feature higher strain, stiffness, and force capability with lower amplifier requirements than similarly sized piezoelectric or electrostrictive active members, at the cost of higher mass. Two different cryogenic temperature magnetostrictive materials were tested at liquid nitrogen temperatures, both with larger strain capability than the room temperature magnetostrictive materials. The cryogenic active member development included the design and fabrication of a cryostat that allows operation of the cryogenic active member in a space structure testbed.

Structural Pain Compensating Flight Control

Science.gov (United States)

Miller, Chris J.

2014-01-01

The problem of control command and maneuver induced structural loads is an important aspect of any control system design. Designers must design the aircraft structure and the control architecture to achieve desired piloted control responses while limiting the imparted structural loads. The classical approach is to build the structure with high margins, restrict control surface commands to known good combinations, and train pilots to follow procedural maneuvering limitations. With recent advances in structural sensing and the continued desire to improve safety and vehicle fuel efficiency, it is both possible and desirable to develop control architectures that enable lighter vehicle weights while maintaining and improving protection against structural damage.

Propose Reactor Control and Monitoring System for RTP

International Nuclear Information System (INIS)

Mohd Sabri Minhat; Izhar Abu Hussin; Mohd Idris Taib; Mohd Khairulezwan Abdul Manan; Nurfarhana Ayuni Joha

2011-01-01

Reactor control and monitoring system is a one of the important features used in reactor. The control and monitoring must come together to provide safety, excellent performance and reliable in nuclear reactor technology application. Objectives of this technical paper are to design and propose reactor control system and reactor monitoring system in Research Reactor (RTP) for Reactor Upgrading Project. (author)

Proposed torque optimized behavior for digital speed control of induction motors

Energy Technology Data Exchange (ETDEWEB)

Metwally, H.M.B.; El-Shewy, H.M.; El-Kholy, M.M. [Zagazig Univ., Dept. of Electrical Engineering, Zagazig (Egypt); Abdel-Kader, F.E. [Menoufyia Univ., Dept. of Electrical Engineering, Menoufyia (Egypt)

2002-09-01

In this paper, a control strategy for speed control of induction motors with field orientation is proposed. The proposed method adjusts the output voltage and frequency of the converter to operate the motor at the desired speed with maximum torque per ampere at all load torques keeping the torque angle equal to 90 deg. A comparison between the performance characteristics of a 2 hp induction motor using three methods of speed control is presented. These methods are the proposed method, the direct torque control method and the constant V/f method. The comparison showed that better performance characteristics are obtained using the proposed speed control strategy. A computer program, based on this method, is developed. Starting from the motor parameters, the program calculates a data set for the stator voltage and frequency required to obtain maximum torque per ampere at any motor speed and load torque. This data set can be used by the digital speed control system of induction motors. (Author)

Structural sensing of interior sound for active control of noise in structural-acoustic cavities.

Science.gov (United States)

Bagha, Ashok K; Modak, S V

2015-07-01

This paper proposes a method for structural sensing of acoustic potential energy for active control of noise in a structural-acoustic cavity. The sensing strategy aims at global control and works with a fewer number of sensors. It is based on the established concept of radiation modes and hence does not add too many states to the order of the system. Acoustic potential energy is sensed using a combination of a Kalman filter and a frequency weighting filter with the structural response measurements as the inputs. The use of Kalman filter also makes the system robust against measurement noise. The formulation of the strategy is presented using finite element models of the system including that of sensors and actuators so that it can be easily applied to practical systems. The sensing strategy is numerically evaluated in the framework of Linear Quadratic Gaussian based feedback control of interior noise in a rectangular box cavity with a flexible plate with single and multiple pairs of piezoelectric sensor-actuator patches when broadband disturbances act on the plate. The performance is compared with an "acoustic filter" that models the complete transfer function from the structure to the acoustic domain. The sensing performance is also compared with a direct estimation strategy.

Double-beam cantilever structure with embedded intelligent damping block: Dynamics and control

Science.gov (United States)

Szmidt, Tomasz; Pisarski, Dominik; Bajer, Czesław; Dyniewicz, Bartłomiej

2017-08-01

In this paper a semi-active method to control the vibrations of twin beams connected at their tips by a smart damping element is investigated. The damping element can be made of a magnetorheological elastomer or a smart material of another type, for instance vacuum packed particles. What is crucial is the ability to modify the storage and loss moduli of the damping block by means of devices attached directly to the vibrating structure. First, a simple dynamical model of the system is proposed. The continuous model is discretized using the Galerkin procedure. Then, a practical state-feedback control law is developed. The control strategy aims at achieving the best instantaneous energy dissipation of the system. Numerical simulations confirm its effectiveness in reducing free vibrations. The proposed control strategy appears to be robust in the sense that its application does not require any knowledge of the initial conditions imposed on the structure, and its performance is better than passive solutions, especially for the system induced in the first mode.

Structural Pest Control.

Science.gov (United States)

Kahn, M. S.; Hoffman, W. M.

This manual is designed for those who seek certification as pesticide applicators for industrial, institutional, structural, and health-related pest control. It is divided into six sections covering general pest control, wood-destroying organisms, bird control, fumigation, rodent control, and industrial weed control. The manual gives information…

Active power filter for harmonic compensation using a digital dual-mode-structure repetitive control approach

DEFF Research Database (Denmark)

Zou, Zhixiang; Wang, Zheng; Cheng, Ming

2012-01-01

This paper presents an digital dual-mode-structure repetitive control approach for the single-phase shunt active power filter (APF), which aims to enhance the tracking ability and eliminate arbitrary order harmonic. The proposed repetitive control scheme blends the characteristics of both odd......-harmonic repetitive control and even-harmonic repetitive control. Moreover, the convergence rate is faster than conventional repetitive controller. Additionally, the parameters have been designed and optimized for the dual-mode structure repetitive control to improve the performance of APF system. Experimental...

Experimental Active Vibration Control in Truss Structures Considering Uncertainties in System Parameters

Directory of Open Access Journals (Sweden)

Douglas Domingues Bueno

2008-01-01

Full Text Available This paper deals with the study of algorithms for robust active vibration control in flexible structures considering uncertainties in system parameters. It became an area of enormous interest, mainly due to the countless demands of optimal performance in mechanical systems as aircraft, aerospace, and automotive structures. An important and difficult problem for designing active vibration control is to get a representative dynamic model. Generally, this model can be obtained using finite element method (FEM or an identification method using experimental data. Actuators and sensors may affect the dynamics properties of the structure, for instance, electromechanical coupling of piezoelectric material must be considered in FEM formulation for flexible and lightly damping structure. The nonlinearities and uncertainties involved in these structures make it a difficult task, mainly for complex structures as spatial truss structures. On the other hand, by using an identification method, it is possible to obtain the dynamic model represented through a state space realization considering this coupling. This paper proposes an experimental methodology for vibration control in a 3D truss structure using PZT wafer stacks and a robust control algorithm solved by linear matrix inequalities.

Experimental investigation of the seismic control of a nonlinear soil-structure system using MR dampers

International Nuclear Information System (INIS)

Li, Hui; Wang, Jian

2011-01-01

This paper reports the results of an experimental study conducted to demonstrate the feasibility and capability of magnetorheological (MR) dampers commanded by a decentralized control algorithm for seismic control of nonlinear civil structures considering soil-structure interaction (SSI). A two-story reinforced concrete (RC) frame resting in a laminar soil container is employed as the test specimen, and two MR dampers equipped in the first story are used to mitigate the response of this frame subjected to various intensity seismic excitations. A hyperbolic tangent function is used to represent the hysteretic behavior of the MR damper and a decentralized control approach for commanding MR dampers is proposed and implemented in the shaking table tests. Only the response of the first story is feedback for control command calculation of the MR dampers. The results indicate that the MR damper can effectively reduce the response of the soil-structure system, even when the soil-structure system presents complex nonlinear hysteretic behavior. The robustness of the proposed decentralized control algorithm is validated through the shaking table tests on the soil-structure system with large uncertainty. The most interesting findings in this paper are that MR dampers not only mitigate the superstructure response, but also reduce the soil response, pile response and earth pressure on the pile foundation

Review of Differences of Steel related Properties between Proposals of European Structural Codes

DEFF Research Database (Denmark)

Hertz, Kristian Dahl

Differences of Steel related Properties between fire chapters of the Proposals of European Structural Codes are indicated for the same physical properties, the right properties are found and it is proposed to use these properties in all codes.......Differences of Steel related Properties between fire chapters of the Proposals of European Structural Codes are indicated for the same physical properties, the right properties are found and it is proposed to use these properties in all codes....

Energy Center Structure Optimization by using Smart Technologies in Process Control System

Science.gov (United States)

Shilkina, Svetlana V.

2018-03-01

The article deals with practical application of fuzzy logic methods in process control systems. A control object - agroindustrial greenhouse complex, which includes its own energy center - is considered. The paper analyzes object power supply options taking into account connection to external power grids and/or installation of own power generating equipment with various layouts. The main problem of a greenhouse facility basic process is extremely uneven power consumption, which forces to purchase redundant generating equipment idling most of the time, which quite negatively affects project profitability. Energy center structure optimization is largely based on solving the object process control system construction issue. To cut investor’s costs it was proposed to optimize power consumption by building an energy-saving production control system based on a fuzzy logic controller. The developed algorithm of automated process control system functioning ensured more even electric and thermal energy consumption, allowed to propose construction of the object energy center with a smaller number of units due to their more even utilization. As a result, it is shown how practical use of microclimate parameters fuzzy control system during object functioning leads to optimization of agroindustrial complex energy facility structure, which contributes to a significant reduction in object construction and operation costs.

Consensus positive position feedback control for vibration attenuation of smart structures

Science.gov (United States)

Omidi, Ehsan; Nima Mahmoodi, S.

2015-04-01

This paper presents a new network-based approach for active vibration control in smart structures. In this approach, a network with known topology connects collocated actuator/sensor elements of the smart structure to one another. Each of these actuators/sensors, i.e., agent or node, is enhanced by a separate multi-mode positive position feedback (PPF) controller. The decentralized PPF controlled agents collaborate with each other in the designed network, under a certain consensus dynamics. The consensus constraint forces neighboring agents to cooperate with each other such that the disagreement between the time-domain actuation of the agents is driven to zero. The controller output of each agent is calculated using state-space variables; hence, optimal state estimators are designed first for the proposed observer-based consensus PPF control. The consensus controller is numerically investigated for a flexible smart structure, i.e., a thin aluminum beam that is clamped at its both ends. Results demonstrate that the consensus law successfully imposes synchronization between the independently controlled agents, as the disagreements between the decentralized PPF controller variables converge to zero in a short time. The new consensus PPF controller brings extra robustness to vibration suppression in smart structures, where malfunctions of an agent can be compensated for by referencing the neighboring agents’ performance. This is demonstrated in the results by comparing the new controller with former centralized PPF approach.

Proposed Federal Gun-Control Amendment. Student Forum.

Science.gov (United States)

Mertz, Gayle; Mertz, David

1995-01-01

Presents an outline for a student-run forum on a proposed federal gun control amendment. Procedures include mandatory reading assignments and researching the issue. Students role-play fictional representative characters and later facilitate discussions. Concludes with a vote on the amendment. (MJP)

Structural Elements Regulating AAA+ Protein Quality Control Machines.

Science.gov (United States)

Chang, Chiung-Wen; Lee, Sukyeong; Tsai, Francis T F

2017-01-01

Members of the ATPases Associated with various cellular Activities (AAA+) superfamily participate in essential and diverse cellular pathways in all kingdoms of life by harnessing the energy of ATP binding and hydrolysis to drive their biological functions. Although most AAA+ proteins share a ring-shaped architecture, AAA+ proteins have evolved distinct structural elements that are fine-tuned to their specific functions. A central question in the field is how ATP binding and hydrolysis are coupled to substrate translocation through the central channel of ring-forming AAA+ proteins. In this mini-review, we will discuss structural elements present in AAA+ proteins involved in protein quality control, drawing similarities to their known role in substrate interaction by AAA+ proteins involved in DNA translocation. Elements to be discussed include the pore loop-1, the Inter-Subunit Signaling (ISS) motif, and the Pre-Sensor I insert (PS-I) motif. Lastly, we will summarize our current understanding on the inter-relationship of those structural elements and propose a model how ATP binding and hydrolysis might be coupled to polypeptide translocation in protein quality control machines.

A virtual structure approach to formation control of unicycle mobile robots using mutual coupling

NARCIS (Netherlands)

Sadowska, A.D.; van den Broek, T.H.A.; Huijberts, H.J.C.; Wouw, van de N.; Kostic, D.; Nijmeijer, H.

2011-01-01

In this article, the formation control problem for unicycle mobile robots is studied. A distributed virtual structure control strategy with mutual coupling between the robots is proposed. The rationale behind the introduction of the coupling terms is the fact that these introduce additional

Modeling, Control, and Estimation of Flexible, Aerodynamic Structures

Science.gov (United States)

Ray, Cody W.

Engineers have long been inspired by nature’s flyers. Such animals navigate complex environments gracefully and efficiently by using a variety of evolutionary adaptations for high-performance flight. Biologists have discovered a variety of sensory adaptations that provide flow state feedback and allow flying animals to feel their way through flight. A specialized skeletal wing structure and plethora of robust, adaptable sensory systems together allow nature’s flyers to adapt to myriad flight conditions and regimes. In this work, motivated by biology and the successes of bio-inspired, engineered aerial vehicles, linear quadratic control of a flexible, morphing wing design is investigated, helping to pave the way for truly autonomous, mission-adaptive craft. The proposed control algorithm is demonstrated to morph a wing into desired positions. Furthermore, motivated specifically by the sensory adaptations organisms possess, this work transitions to an investigation of aircraft wing load identification using structural response as measured by distributed sensors. A novel, recursive estimation algorithm is utilized to recursively solve the inverse problem of load identification, providing both wing structural and aerodynamic states for use in a feedback control, mission-adaptive framework. The recursive load identification algorithm is demonstrated to provide accurate load estimate in both simulation and experiment.

Modular Hybrid Energy Concept Employing a Novel Control Structure Based on a Simple Analog System

Directory of Open Access Journals (Sweden)

PETREUS, D.

2016-05-01

Full Text Available This paper proposes a novel control topology which enables the setup of a low cost analog system leading to the implementation of a modular energy conversion system. The modular concept is based on hybrid renewable energy (solar and wind and uses high voltage inverters already available on the market. An important feature of the proposed topology is a permanently active current loop, which assures short circuit protection and simplifies the control loops compensation. The innovative analogue solution of the control structure is based on a dedicated integrated circuit (IC for power factor correction (PFC circuits, used in a new configuration, to assure an efficient inverter start-up. The energy conversion system (control structure and maximum power point tracking algorithm is simulated using a new macromodel-based concept, which reduces the usual computational burden of the simulator and achieves high processing speed. The proposed novel system is presented in this article from concept, through the design and implementation stages, is verified through simulation and is validated by experimental results.

Study the topology of Branciari metric space via the structure proposed by Csaszar

Directory of Open Access Journals (Sweden)

Dong ZHANG

2017-06-01

Full Text Available In this paper, we topologically study the generalized metric space proposed by Branciari [3] via the weak structure proposed by Cs´asz´ar [9, 10], and compare convergent sequences in several different senses. We also introduce the concepts of available points and unavailable points on such structures. Besides, we define the continuous function on structures and investigate further characterizations of continuous functions.

Proposed structure of a data paper structure as scientific publication

Directory of Open Access Journals (Sweden)

Sandra M. Roa-Martínez

2017-03-01

Full Text Available This paper presents a review of the main motivations and paths for publishing datasets that are generated and managed during the research process. The Data Paper is considered as a form of scientific publication with the same recognition, acceptance and scientific rigor as conventional research articles. Therefore we propose a common structure defined by elements based mainly on dataset metadata. This will enable creators, publishers, consumers and expert peer reviewers to recognise, share, evaluate and facilitate data reuse. Doing so will facilitate information reproducibility, validation of results, and rapid new research generation.

A new electromagnetic shunt damping treatment and vibration control of beam structures

International Nuclear Information System (INIS)

Niu Hongpan; Zhang Xinong; Xie Shilin; Wang Pengpeng

2009-01-01

In this paper a new class of shunted electromagnetic damping treatment is proposed: a non-contact electromagnetic shunt damper (NC-EMSD). The NC-EMSD consists of an electromagnet attached to a host structure, a permanent magnet attached to the fixed boundary and an electrical impedance connected to the terminals of the electromagnet. The electromagnet and the shunt impedance constitute a closed circuit. When the structure vibrates, an induced electromotive force will be produced and results in the electromagnetic force as damping force, which can suppress the vibration of the structure. The model of NC-EMSD is built up based on the equivalent current method. The governing equations of the beam with NC-EMSD are established using Hamilton's principle. The capacitor-matching-inductance (CMI) method and the negative resistive capacitor-matching-inductance (NR-CMI) method are proposed, respectively. Then the vibration control of a cantilever beam with NC-EMSD is simulated and measured by CMI and NR-CMI control methods, respectively. The results show that both the CMI and NR-CMI can attenuate the vibration effectively, and the NR-CMI provides much better control performance than that by CMI. It is indicated as well from the studies that the decrease of either the gap between the magnet pair or the resistance of the shunt impedance contributes to the improvement of control performance

Proposal to extend CSEWG neutron and photon multigroup structures for wider applications

International Nuclear Information System (INIS)

LaBauve, R.J.; Wilson, W.B.

1976-02-01

The 239-group neutron multigroup structure recommended by the Codes and Formats Subcommittee of the cross section evaluation working group (CSEWG) for use in LMFBR design is not well suited for application in certain other areas, particularly thermal reactor design. This report describes a proposal for a neutron group structure consisting of 347 groups, which is an extension of the CSEWG group structure into the thermal range, and also includes more detail in other energy ranges important in LWR, HTGR, GCFR, and CTR design. Similarly, a proposed extension of the CSEWG 94-group photon multigroup structure to 103 groups is described. A subset of the neutron multigroup structure, consisting of 154 groups and for use in power reactor studies, is also presented

Theoretical and experimental investigation of position-controlled semi-active friction damper for seismic structures

Science.gov (United States)

Lu, Lyan-Ywan; Lin, Tzu-Kang; Jheng, Rong-Jie; Wu, Hsin-Hsien

2018-01-01

A semi-active friction damper (SAFD) can be employed for the seismic protection of structural systems. The effectiveness of an SAFD in absorbing seismic energy is usually superior to that of its passive counterpart, since its slip force can be altered in real time according to structural response and excitation. Most existing SAFDs are controlled by adjusting the clamping force applied on the friction interface. Thus, the implementation of SAFDs in practice requires precision control of the clamping force, which is usually substantially larger than the slip force. This may increase the implementation complexity and cost of SAFDs. To avoid this problem, this study proposes a novel position-controlled SAFD, named the leverage-type controllable friction damper (LCFD). The LCFD system combines a traditional passive friction damper and a leverage mechanism with a movable central pivot. By simply controlling the pivot position, the damping force generated by the LCFD system can be adjusted in real time. In order to verify the feasibility of the proposed SAFD, a prototype LCFD was tested by using a shaking table. The test results demonstrate that the equivalent friction force and hysteresis loop of the LCFD can be regulated by controlling the pivot position. By considering 16 ground motions with two different intensities, the adaptive feature of the LCFD for seismic structural control is further demonstrated numerically.

Multiple-source multiple-harmonic active vibration control of variable section cylindrical structures: A numerical study

Science.gov (United States)

Liu, Jinxin; Chen, Xuefeng; Gao, Jiawei; Zhang, Xingwu

2016-12-01

Air vehicles, space vehicles and underwater vehicles, the cabins of which can be viewed as variable section cylindrical structures, have multiple rotational vibration sources (e.g., engines, propellers, compressors and motors), making the spectrum of noise multiple-harmonic. The suppression of such noise has been a focus of interests in the field of active vibration control (AVC). In this paper, a multiple-source multiple-harmonic (MSMH) active vibration suppression algorithm with feed-forward structure is proposed based on reference amplitude rectification and conjugate gradient method (CGM). An AVC simulation scheme called finite element model in-loop simulation (FEMILS) is also proposed for rapid algorithm verification. Numerical studies of AVC are conducted on a variable section cylindrical structure based on the proposed MSMH algorithm and FEMILS scheme. It can be seen from the numerical studies that: (1) the proposed MSMH algorithm can individually suppress each component of the multiple-harmonic noise with an unified and improved convergence rate; (2) the FEMILS scheme is convenient and straightforward for multiple-source simulations with an acceptable loop time. Moreover, the simulations have similar procedure to real-life control and can be easily extended to physical model platform.

Design of a structural and functional hierarchy for planning and control of telerobotic systems

Science.gov (United States)

Acar, Levent; Ozguner, Umit

1989-01-01

Hierarchical structures offer numerous advantages over conventional structures for the control of telerobotic systems. A hierarchically organized system can be controlled via undetailed task assignments and can easily adapt to changing circumstances. The distributed and modular structure of these systems also enables fast response needed in most telerobotic applications. On the other hand, most of the hierarchical structures proposed in the literature are based on functional properties of a system. These structures work best for a few given functions of a large class of systems. In telerobotic applications, all functions of a single system needed to be explored. This approach requires a hierarchical organization based on physical properties of a system and such a hierarchical organization is introduced. The decomposition, organization, and control of the hierarchical structure are considered, and a system with two robot arms and a camera is presented.

Adaptive variable structure control for uncertain chaotic systems containing dead-zone nonlinearity

International Nuclear Information System (INIS)

Yan, J.-J.; Shyu, K.-K.; Lin, J.-S.

2005-01-01

This paper addresses a practical tracking problem for a class of uncertain chaotic systems with dead-zone nonlinearity in the input function. Based on the Lyapunov stability theorem and Barbalat lemma, an adaptive variable structure controller (AVSC) is proposed to ensure the occurrence of the sliding mode even though the control input contains a dead-zone. Also it is worthy of note that the proposed AVSC involves no information of the upper bound of uncertainty. Thus, the limitation of knowing the bound of uncertainty in advance is certainly released. Furthermore, in the sliding mode, the investigated uncertain chaotic system remains insensitive to the uncertainty, and behaves like a linear system. Finally, a well-known Duffing-Holmes chaotic system is used to demonstrate the feasibility of the proposed AVSC

Stochastic Control Synthesis of Systems with Structured Uncertainty

Science.gov (United States)

Padula, Sharon L. (Technical Monitor); Crespo, Luis G.

2003-01-01

This paper presents a study on the design of robust controllers by using random variables to model structured uncertainty for both SISO and MIMO feedback systems. Once the parameter uncertainty is prescribed with probability density functions, its effects are propagated through the analysis leading to stochastic metrics for the system's output. Control designs that aim for satisfactory performances while guaranteeing robust closed loop stability are attained by solving constrained non-linear optimization problems in the frequency domain. This approach permits not only to quantify the probability of having unstable and unfavorable responses for a particular control design but also to search for controls while favoring the values of the parameters with higher chance of occurrence. In this manner, robust optimality is achieved while the characteristic conservatism of conventional robust control methods is eliminated. Examples that admit closed form expressions for the probabilistic metrics of the output are used to elucidate the nature of the problem at hand and validate the proposed formulations.

Urban Traffic Signal System Control Structural Optimization Based on Network Analysis

Directory of Open Access Journals (Sweden)

Li Wang

2013-01-01

Full Text Available Advanced urban traffic signal control systems such as SCOOT and SCATS normally coordinate traffic network using multilevel hierarchical control mechanism. In this mechanism, several key intersections will be selected from traffic signal network and the network will be divided into different control subareas. Traditionally, key intersection selection and control subareas division are executed according to dynamic traffic counts and link length between intersections, which largely rely on traffic engineers’ experience. However, it omits important inherent characteristics of traffic network topology. In this paper, we will apply network analysis approach into these two aspects for traffic system control structure optimization. Firstly, the modified C-means clustering algorithm will be proposed to assess the importance of intersections in traffic network and furthermore determine the key intersections based on three indexes instead of merely on traffic counts in traditional methods. Secondly, the improved network community discovery method will be used to give more reasonable evidence in traffic control subarea division. Finally, to test the effectiveness of network analysis approach, a hardware-in-loop simulation environment composed of regional traffic control system, microsimulation software and signal controller hardware, will be built. Both traditional method and proposed approach will be implemented on simulation test bed to evaluate traffic operation performance indexes, for example, travel time, stop times, delay and average vehicle speed. Simulation results show that the proposed network analysis approach can improve the traffic control system operation performance effectively.

Global control of colored moiré pattern in layered optical structures

Science.gov (United States)

Li, Kunyang; Zhou, Yangui; Pan, Di; Ma, Xueyan; Ma, Hongqin; Liang, Haowen; Zhou, Jianying

2018-05-01

Accurate description of visual effect of colored moiré pattern caused by layered optical structures consisting of gratings and Fresnel lens is proposed in this work. The colored moiré arising from the periodic and quasi-periodic structures is numerically simulated and experimentally verified. It is found that the visibility of moiré pattern generated by refractive optical elements is related to not only the spatial structures of gratings but also the viewing angles. To effectively control the moiré visibility, two constituting gratings are slightly separated. Such scheme is proved to be effective to globally eliminate moiré pattern for displays containing refractive optical films with quasi-periodic structures.

Towards Automatic Decentralized Control Structure Selection

DEFF Research Database (Denmark)

Jørgensen, John Bagterp; Jørgensen, Sten Bay

2000-01-01

for decentralized control is determined automatically, and the resulting decentralized control structure is automatically tuned using standard techniques. Dynamic simulation of the resulting process system gives immediate feedback to the process design engineer regarding practical operability of the process......A subtask in integration of design and control of chemical processes is the selection of a control structure. Automating the selection of the control structure enables sequential integration of process and control design. As soon as the process is specified or computed, a structure....... The control structure selection problem is formulated as a special MILP employing cost coefficients which are computed using Parseval's theorem combined with RGA and IMC concepts. This approach enables selection and tuning of large-scale plant-wide decentralized controllers through efficient combination...

Effects of a GPC-PID control strategy with hierarchical structure for a cooling coil unit

International Nuclear Information System (INIS)

Xu Min; Li Shaoyuan; Cai Wenjian; Lu Lu

2006-01-01

This paper presents a GPC-PID control strategy for a cooling-coil unit in heating, ventilation and air conditioning systems. By analysis of the cooling towers and chillers, different models in the occupied period are considered in each operating condition. Because of the complication of components, well tuned PID controllers are unsatisfied, and the results are poor over a wide range of operation conditions. To solve this problem, a GPC-PID controller with hierarchical structure is proposed based on minimizing the generalized predictive control criterion to tune conventional PID controller parameters. Simulation and experiments show that the proposed controller is able to deal with a wide range of operating conditions and to achieve better performance than conventional methods

Preliminary Study on Structural Optimization with Control Variables Using Equivalent Static Loads for Spring-damper Control Systems

International Nuclear Information System (INIS)

Yoo, Nam-sun; Jung, Ui-Jin; Park, Gyung-Jin; Kim, Tai-Kyung

2014-01-01

An optimization method is proposed for the simultaneous design of structural and control systems using the equivalent static loads. In the past researches, the control parameters of such feedback gains are obtained to improve some performance in the steady-state. However, the actuators which have position and velocity feedback gains should be designed to exhibit a good performance in the time domain. In other words, the system analysis should be conducted for the transient-state in dynamic manner. In this research, a new equivalent static loads method is presented to treat the control variables as the design variables. The equivalent static loads (ESLs) set is defined as a static load set which generates the same displacement field as that from dynamic loads at a certain time. The calculated sets of ESLs are applied as multiple loading conditions in the optimization process. Several examples are solved to validate the proposed method

Control of 2D Flexible Structures by Confinement of Vibrations and Regulation of Their Energy Flow

Directory of Open Access Journals (Sweden)

Fakhreddine Landolsi

2009-01-01

Full Text Available In this paper, we investigate the control of 2D flexible structures by vibration confinement and the regulation of their energy flow along prespecified spatial paths. A discretized-model-based feedback strategy, aiming at confining and suppressing simultaneously the vibration, is proposed. It is assumed that the structure consists of parts that are sensitive to vibrations. The control design introduces a new pseudo-modal matrix derived from the computed eigenvectors of the discretized model. Simulations are presented to show the efficacy of the proposed control law. A parametric study is carried out to examine the effects of the different control parameters on the simultaneous confinement and suppression of vibrations. In addition, we conducted a set of simulations to investigate the flow control of vibrational energy during the confinement-suppression process. We found that the energy flow can be regulated via a set of control parameters for different confinement configurations.

Towards Automatic Decentralized Control Structure Selection

DEFF Research Database (Denmark)

for decentralized control is determined automatically, and the resulting decentralized control structure is automatically tuned using standard techniques. Dynamic simulation of the resulting process system gives immediate feedback to the process design engineer regarding practical operability of the process......A subtask in integration of design and control of chemical processes is the selection of a control structure. Automating the selection of the control structure enables sequential integration of process and controld esign. As soon as the process is specified or computed, a structure....... The control structure selection problem is formulated as a special MILP employing cost coefficients which are computed using Parseval's theorem combined with RGA and IMC concepts. This approach enables selection and tuning of large-scale plant-wide decentralized controllers through efficient combination...

Application of superconducting coils to VAR control in electric power systems: a proposal

International Nuclear Information System (INIS)

Boenig, H.J.; Hassenzahl, W.V.

1979-11-01

During the last eight years, static VAR-control systems with thyristor-controlled, room-temperature reactors have been used in electrical systems for voltage control and system stabilization. In this proposal, we describe a new static VAR-control system that uses an asymmetrically controlled Graetz bridge and a superconducting dc coil. Preliminary studies indicate that the proposed system will have lower overall losses and that its capital cost and electrical characteristics are comparable to those of a conventional system. Three- and four-year programs for developing the electronic circuitry and superconducting coils for VAR control, culminating in the installation and testing of an approx. 40-MVAR system, are proposed

Robust distributed model predictive control of linear systems with structured time-varying uncertainties

Science.gov (United States)

Zhang, Langwen; Xie, Wei; Wang, Jingcheng

2017-11-01

In this work, synthesis of robust distributed model predictive control (MPC) is presented for a class of linear systems subject to structured time-varying uncertainties. By decomposing a global system into smaller dimensional subsystems, a set of distributed MPC controllers, instead of a centralised controller, are designed. To ensure the robust stability of the closed-loop system with respect to model uncertainties, distributed state feedback laws are obtained by solving a min-max optimisation problem. The design of robust distributed MPC is then transformed into solving a minimisation optimisation problem with linear matrix inequality constraints. An iterative online algorithm with adjustable maximum iteration is proposed to coordinate the distributed controllers to achieve a global performance. The simulation results show the effectiveness of the proposed robust distributed MPC algorithm.

Immune algorithm based active PID control for structure systems

International Nuclear Information System (INIS)

Lee, Young Jin; Cho, Hyun Cheol; Lee, Kwon Soon

2006-01-01

An immune algorithm is a kind of evolutional computation strategies, which is developed in the basis of a real immune mechanism in the human body. Recently, scientific or engineering applications using this scheme are remarkably increased due to its significant ability in terms of adaptation and robustness for external disturbances. Particularly, this algorithm is efficient to search optimal parameters against complicated dynamic systems with uncertainty and perturbation. In this paper, we investigate an immune algorithm embedded Proportional Integral Derivate (called I P ID) control, in which an optimal parameter vector of the controller is determined offline by using a cell-mediated immune response of the immunized mechanism. For evaluation, we apply the proposed control to mitigation of vibrations for nonlinear structural systems, cased by external environment load such as winds and earthquakes. Comparing to traditional controls under same simulation scenarios, we demonstrate the innovation control is superior especially in robustness aspect

Proposal to extend CSEWG neutron and photon multigroup structures for wider applications. [Tables

Energy Technology Data Exchange (ETDEWEB)

LaBauve, R.J.; Wilson, W.B.

1976-02-01

The 239-group neutron multigroup structure recommended by the Codes and Formats Subcommittee of the cross section evaluation working group (CSEWG) for use in LMFBR design is not well suited for application in certain other areas, particularly thermal reactor design. This report describes a proposal for a neutron group structure consisting of 347 groups, which is an extension of the CSEWG group structure into the thermal range, and also includes more detail in other energy ranges important in LWR, HTGR, GCFR, and CTR design. Similarly, a proposed extension of the CSEWG 94-group photon multigroup structure to 103 groups is described. A subset of the neutron multigroup structure, consisting of 154 groups and for use in power reactor studies, is also presented.

The three-hinged arch as an example of piezomechanic passive controlled structure

Science.gov (United States)

Pagnini, Luisa Carlotta; Piccardo, Giuseppe

2016-09-01

Although piezoelectric transducers are employed in a variety of fields, their application for vibration control of civil or industrial structures has not yet been fully developed, at the best of authors' knowledge. Thanks to a new generation of ever more performing piezoceramic materials and to the recent development of scientific proposals based on a very simple technology, this paper presents a step forward to engineering applications for the control of structural systems. A three-hinged arch controlled by piezoelectric stack actuators and passive RL electrical circuits is chosen as a simple structural model that may represent the starting point for a generalization to the most common typologies of civil and industrial engineering structures. Based on the concept of electromechanical analogy, the evolution equations are obtained through a consistent Lagrangian approach. A multimodal vibration suppression is guaranteed by the spectral analogy between the mechanical and electrical components. Preliminary applications related to free oscillations, with one or more actuators on each member, seem to lead to excellent performance in terms of multimodal damping and dissipated energy.

Control of the wavelength dependent thermo-optic coefficients in structured fibres

DEFF Research Database (Denmark)

Sørensen, Henrik Rokkjær; Canning, J.; Lægsgaard, Jesper

2006-01-01

By controlling the fibre geometry, the fraction of optical field within the holes and the inserted material of a photonic crystal fibre, we demonstrate that it is possible to engineer any arbitrary wavelength-dependent thermo-optic coefficient. The possibility of making a fibre with a zero temper...... temperature dependent thermo-optic coefficient, ideal for packaging of structured fibre gratings, is proposed and explored....

A proposal to develop a high temperature structural design guideline for HTGR components

International Nuclear Information System (INIS)

Hada, K.

1989-01-01

This paper presents some proposals for developing a high-temperature structural design guideline for HTGR structural components. It is appropriate that a basis for developing high-temperature structural design rules is rested on well-established elevated-temperature design guidelines, if the same failure modes are expected for high-temperature components as considered in such design guidelines. As for the applicability of ASME B and PV Code Case N-47 to structural design rules for high-temperature components (service temperatures ≥ 900 deg. C), the following critical issues on material properties and service life evaluation rules have been pointed out. (i) no work-hardening of stress-strain curves at high temperatures due to dynamic recrystallization; (ii) issues relating to very significant creep; (iii) ductility loss after long-term ageing at high temperatures; (iv) validity of life-fraction rule (Robinson-Taira rule) as creep-fatigue damage evaluation rule. Furthermore, the validity of design margins of elevated-temperature structural design guidelines to high-temperature design rules should be clarified. Solutions and proposals to these issues are presented in this paper. Concerning no work-hardening due to dynamic recrystallization, it is shown that viscous effects cannot be neglected even at high extension rate for tensile tests, and that changes in viscous deformation rates by dynamic recrystallization should be taken into account. The extension rate for tensile tests is proposed to change at high temperatures. The solutions and proposals to the above-mentioned issues lead to the conclusion that the design methodologies of N-47 are basically applicable to the high-temperature structural design guideline for HTGR structural components in service at about 900 deg. C. (author). 9 refs, 5 figs

Proposal of inspection methodology for environment radiological control

International Nuclear Information System (INIS)

Martins, Nadia Soido Falcao

2005-01-01

The Radiation Protection and Dosimetry Institute (IRD) of the Brazilian Nuclear Energy Commission (CNEN) is in charge of verifying that the self-monitoring operator is effective to control the radiological quality of environmental around the nuclear facilities and carried out in accordance with the regulatory requirements. While a long time, the verification of compliance was kept by the conduction of large scale monitoring programs around all the authorized installations. The IRD decided to reformulate its performance behavior, starting another kind of control program, due to the number increase of nuclear installations and the diversity of activities conducted by the operators. This program, so-called Monitoring Control Program (PCM) is a regulatory activity developed by the Environmental Impact Assessment Service (SEAIA) of IRD and has the aim of check the effectiveness of authorized self-control. Actually the regulatory control of environmental radiological integrity around the authorized nuclear installation essentially depends on the effectiveness of regulatory inspections fulfilled by the SEAIA/IRD. Due to the implementation of modern practices of management in the IRD, specially the quality management system on regulatory inspection activities, emerged the need of unify these actions. It was also necessary to establish standard procedures required for inspection conduction. This work proposes one methodology for the inspections of environmental radiological control suitable to assure the compliance and effectiveness of environmental and effluent monitoring programs conducted by the operator, through the systematic verification of compliance and data quality assessment. The proposed methodology seeks to attend the appeals for high control standards of environment protection and public health. Here, we presented as products of this work: The inspection handbook and checklists for inspections; one framework for sampling, handling, recording and reporting of

Breakup ice control structure for the Salmon River in Connecticut

International Nuclear Information System (INIS)

Tuthill, A.M.; White, K.D.

1997-01-01

The Salmon River ice jam problem was investigated and a conceptual design for a breakup ice control structure was developed. Historical ice jam events were reviewed and an ice observation program was conducted during the winter of 1994-95. The factors affecting ice jam frequency and severity were examined. The factors included daily temperature, rainfall quantity and intensity, Salmon River stage and discharge, and Connecticut River tide levels. First, a numerical model was developed to simulate a worst case scenario for ice jams, followed by a conceptual design for a concrete pier ice control structure under two ice breakup scenarios. The first scenario assumed that a semi-intact ice sheet would rest against the piers and retain a floating equilibrium jam upstream, allowing water discharge to pass beneath. The second scenario was based on the assumption that a grounded ice jam in direct contact with the piers would divert water flow around the structure via an armored channel in the overbank area. An ice retention structure consisting of a row of concrete piers, spaced across the main channel, 60 m upstream of an existing dam, was proposed. 11 refs., 6 figs

Glass-based confined structures enabling light control

Energy Technology Data Exchange (ETDEWEB)

Chiappini, Andrea; Normani, Simone; Chiasera, Alessandro [IFN–CNR CSMFO Lab., and FBK Photonics Unit via alla Cascata 56/C Povo, 38123 Trento (Italy); Lukowiak, Anna [Institute of Low Temperature and Structure Research PAS, Okolna St. 2, 50-422 Wroclaw (Poland); Vasilchenko, Iustyna [IFN–CNR CSMFO Lab., and FBK Photonics Unit via alla Cascata 56/C Povo, 38123 Trento (Italy); Dipartimento di Fisica, Università di Trento, via Sommarive 14 Povo, 38123Trento (Italy); Ristic, Davor [Institut Ruđer Bošković, Bijenička cesta 54, 10000 Zagreb (Croatia); Boulard, Brigitte [IMMM, CNRS Equipe Fluorures, Université du Maine, Av. Messiaen, 72085 Le Mans cedex 9 (France); Dorosz, Dominik [Department of Power Engineering, Photonics and Lighting Technology, Bialystok University of Technology, Wiejska Street 45D, 15-351 Bialystok (Poland); Scotognella, Francesco [Center for Nano Science and Technology@PoliMi, Istituto Italiano di Tecnologia, Via Giovanni Pascoli, 70/3, 20133, Milan (Italy); Politecnico di Milano, Dipartimento di Fisica and Istituto di Fotonica e Nanotecnologie CNR, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); Vaccari, Alessandro [FBK -CMM, ARES Unit, 38123 Trento (Italy); Taccheo, Stefano [College of Engineering, Swansea University, Singleton Park, SA2 8PP, Swansea (United Kingdom); Pelli, Stefano; Righini, Giancarlo C. [IFAC - CNR, MiPLab., 50019 Sesto Fiorentino (Italy); Museo Storico della Fisica e Centro di Studi e Ricerche “Enrico Fermi”, Piazza del Viminale 1, 00184 Roma (Italy); Conti, Gualtiero Nunzi [IFAC - CNR, MiPLab., 50019 Sesto Fiorentino (Italy); Ramponi, Roberta [Politecnico di Milano, Dipartimento di Fisica and Istituto di Fotonica e Nanotecnologie CNR, Piazza Leonardo da Vinci 32, 20133 Milano (Italy); and others

2015-04-24

When a luminescent ion is confined in a system characterized by one or more specific properties such as spatial size, geometrical dimension and shape, refractive index, local crystal field, cut-off vibrational energy and so on, it's possible to control its emission. The control of branching ratios as a function of the composition, the luminescence enhancement induced by a photonic crystal, or the laser action in a microresonator, are well known examples of light control. Photonic glass-based structures are extremely viable systems to exploit the above mentioned properties and in our research team we have successfully fabricated luminescent photonic structures by different techniques, including sol-gel, rf sputtering, drawing, melting, and physical vapour deposition. Here we will discuss some of them with the aim to make the reader aware of the chemical-physical properties related to each specific system. We will demonstrate that glass ceramic waveguides in some cases present superior spectroscopic properties in respect to the parent glass, that compositional properties can play a positive role in reducing luminescence quenching and in developing novel planar waveguides and fibers, that colloids allow to obtain high internal quantum efficiency and that photonic crystals, microcavities and microresonators can enable the handling of the rare earth luminescence. Finally, the pros and cons of the systems and of the different techniques employed for their fabrication will be discussed and some perspectives concerning the glass photonics will be proposed looking at both possible applications and investigation of physical properties.

Glass-based confined structures enabling light control

International Nuclear Information System (INIS)

Chiappini, Andrea; Normani, Simone; Chiasera, Alessandro; Lukowiak, Anna; Vasilchenko, Iustyna; Ristic, Davor; Boulard, Brigitte; Dorosz, Dominik; Scotognella, Francesco; Vaccari, Alessandro; Taccheo, Stefano; Pelli, Stefano; Righini, Giancarlo C.; Conti, Gualtiero Nunzi; Ramponi, Roberta

2015-01-01

When a luminescent ion is confined in a system characterized by one or more specific properties such as spatial size, geometrical dimension and shape, refractive index, local crystal field, cut-off vibrational energy and so on, it's possible to control its emission. The control of branching ratios as a function of the composition, the luminescence enhancement induced by a photonic crystal, or the laser action in a microresonator, are well known examples of light control. Photonic glass-based structures are extremely viable systems to exploit the above mentioned properties and in our research team we have successfully fabricated luminescent photonic structures by different techniques, including sol-gel, rf sputtering, drawing, melting, and physical vapour deposition. Here we will discuss some of them with the aim to make the reader aware of the chemical-physical properties related to each specific system. We will demonstrate that glass ceramic waveguides in some cases present superior spectroscopic properties in respect to the parent glass, that compositional properties can play a positive role in reducing luminescence quenching and in developing novel planar waveguides and fibers, that colloids allow to obtain high internal quantum efficiency and that photonic crystals, microcavities and microresonators can enable the handling of the rare earth luminescence. Finally, the pros and cons of the systems and of the different techniques employed for their fabrication will be discussed and some perspectives concerning the glass photonics will be proposed looking at both possible applications and investigation of physical properties

Neuro-fuzzy inverse model control structure of robotic manipulators utilized for physiotherapy applications

Directory of Open Access Journals (Sweden)

A.A. Fahmy

2013-12-01

Full Text Available This paper presents a new neuro-fuzzy controller for robot manipulators. First, an inductive learning technique is applied to generate the required inverse modeling rules from input/output data recorded in the off-line structure learning phase. Second, a fully differentiable fuzzy neural network is developed to construct the inverse dynamics part of the controller for the online parameter learning phase. Finally, a fuzzy-PID-like incremental controller was employed as Feedback servo controller. The proposed control system was tested using dynamic model of a six-axis industrial robot. The control system showed good results compared to the conventional PID individual joint controller.

Active Power Filter DC Bus Voltage Piecewise Reaching Law Variable Structure Control

OpenAIRE

Liu, Baolian; Ding, Zujun; Zhao, Huanyu; Jin, Defei

2014-01-01

The DC bus voltage stability control is one key technology to ensure that Active Power Filter (APF) operates stably. The external disturbances such as power grid and load fluctuation and the system parameters changing may affect the stability of APF DC bus voltage and the normal operation of APF. The mathematical model of DC bus voltage is established according to power balance principle and a DC bus voltage piecewise reaching law variable structure control algorithm is proposed to solve the ...

Influence of Control Structures and Load Parameters on Performance of a Pseudo Direct Drive

Directory of Open Access Journals (Sweden)

Mohammed Bouheraoua

2014-07-01

Full Text Available The paper describes an in-depth and systematic analysis of a pseudo direct drive permanent magnet machine in closed loop control. Due to the torque being transmitted from the high-speed rotor (HSR to the low-speed rotor (LSR, through a relatively low stiffness magnetic gear with non-linear characteristics, speed oscillations appear in the drive output with a conventional proportional integral (PI controller. Therefore two candidate controllers have been proposed as an alternative to the PI control and all controllers have been optimally tuned with a genetic algorithm against a defined criterion. Furthermore, closed loop models are established in the complex frequency domain to determine the system damping and the cause of the oscillations. Consequently, the best controller structure that improves the dynamic behaviour of the system in terms of speed tracking and disturbance rejection could be identified, based on the frequency domain analysis. Experimental results are presented to validate the analysis and the proposed control technique.

A Reactive Blended Learning Proposal for an Introductory Control Engineering Course

Science.gov (United States)

Mendez, Juan A.; Gonzalez, Evelio J.

2010-01-01

As it happens in other fields of engineering, blended learning is widely used to teach process control topics. In this paper, the inclusion of a reactive element--a Fuzzy Logic based controller--is proposed for a blended learning approach in an introductory control engineering course. This controller has been designed in order to regulate the…

Power system damping - Structural aspects of controlling active power

Energy Technology Data Exchange (ETDEWEB)

Samuelsson, O.

1997-04-01

Environmental and economical aspects make it difficult to build new power lines and to reinforce existing ones. The continued growth in demand for electric power must therefore to a great extent be met by increased loading of available lines. A consequence is that power system damping is reduced, leading to a risk of poorly damped power oscillations between the generators. This thesis proposes the use of controlled active loads to increase damping of such electro-mechanical oscillations. The focus is on structural aspects of controller interaction and of sensor and actuator placement. On-off control based on machine frequency in a single machine infinite bus system is analysed using energy function analysis and phase plane plots. An on-off controller with estimated machine frequency as input has been implemented. At a field test it damped oscillations of a 0.9 MW hydro power generator by controlling a 20kW load. The linear analysis uses two power system models with three and twenty-three machines respectively. Each damper has active power as output and local bus frequency or machine frequency as input. The power system simulator EUROSTAG is used both for generation of the linearized models and for time simulations. Measures of active power mode controllability and phase angle mode observability are obtained from the eigenvectors of the differential-algebraic models. The geographical variation in the network of these quantities is illustrated using the resemblance to bending modes of flexible mechanical structures. Eigenvalue sensitivities are used to determine suitable damper locations. A spring-mass equivalent to an inter-area mode provides analytical expressions, that together with the concept of impedance matching explain the structural behaviour of the power systems. For large gains this is investigated using root locus plots. 64 refs, 99 figs, 20 tabs

Semi-active control for vibration mitigation of structural systems incorporating uncertainties

International Nuclear Information System (INIS)

Miah, Mohammad S; Chatzi, Eleni N; Weber, Felix

2015-01-01

This study introduces a novel semi-active control scheme, where the linear-quadratic regulator (LQR) is combined with an unscented Kalman filter (UKF) observer, for the real-time mitigation of structural vibration. Due to a number of factors, such as environmental effects and ageing processes, the controlled system may be characterized by uncertainties. The UKF, which comprises a nonlinear observer, is employed herein for devising an adaptive semi-active control scheme capable of tackling such a challenge. This is achieved through the real-time realization of joint state and parameter estimation during the structural control process via the proposed LQR-UKF approach. The behavior of the introduced scheme is exemplified through two numerical applications. The efficacy of the devised methodology is firstly compared against the standard LQR-KF approach in a linear benchmark application where the system model is assumed known a priori, and secondly, the method is validated on a joint state and parameter estimation problem where the system model is assumed uncertain, formulated as nonlinear, and updated in real-time. (paper)

Re-centering variable friction device for vibration control of structures subjected to near-field earthquakes

Science.gov (United States)

Ozbulut, Osman E.; Hurlebaus, Stefan

2011-11-01

This paper proposes a re-centering variable friction device (RVFD) for control of civil structures subjected to near-field earthquakes. The proposed hybrid device has two sub-components. The first sub-component of this hybrid device consists of shape memory alloy (SMA) wires that exhibit a unique hysteretic behavior and full recovery following post-transformation deformations. The second sub-component of the hybrid device consists of variable friction damper (VFD) that can be intelligently controlled for adaptive semi-active behavior via modulation of its voltage level. In general, installed SMA devices have the ability to re-center structures at the end of the motion and VFDs can increase the energy dissipation capacity of structures. The full realization of these devices into a singular, hybrid form which complements the performance of each device is investigated in this study. A neuro-fuzzy model is used to capture rate- and temperature-dependent nonlinear behavior of the SMA components of the hybrid device. An optimal fuzzy logic controller (FLC) is developed to modulate voltage level of VFDs for favorable performance in a RVFD hybrid application. To obtain optimal controllers for concurrent mitigation of displacement and acceleration responses, tuning of governing fuzzy rules is conducted by a multi-objective heuristic optimization. Then, numerical simulation of a multi-story building is conducted to evaluate the performance of the hybrid device. Results show that a re-centering variable friction device modulated with a fuzzy logic control strategy can effectively reduce structural deformations without increasing acceleration response during near-field earthquakes.

Control Structure Impact on the Flying Performance of the Multi-Rotor VTOL Platform - Design, Analysis and Experimental Validation

Directory of Open Access Journals (Sweden)

Roman Czyba

2013-01-01

Full Text Available The aim of this research is to examine the different control strategies for the unmanned aerial vehicles (UAV. The control task is formulated as an angular stabilization of the four rotor platform, and also as a tracking problem of chosen state variables. The PID algorithm has been considered in three structures in respect of the optimal control signal applied to the actuators. For better performance of the quadrotor in hover mode the cascade control system has been proposed. The simulation results of attitude control with different PID controller architectures are presented, and confirm the effectiveness of the proposed control structure and theoretical expectations. Moreover, the design and the practical realization of the control architecture on the experimental aerial vehicle are described. The fast prototyping method together with Matlab/Simulink software and DAQ hardware are used for both evolution and validation of control algorithms. The capacity of the attitude stabilization system is important in the development process of more advanced functionality of autonomous flying vehicles; therefore it needs to be highlighted and taken into careful consideration.

New proposal on the development of machine protection functions for ITER diagnostics control

International Nuclear Information System (INIS)

Yamamoto, Tsuyoshi; Yatsuka, Eiichi; Hatae, Takaki; Takeuchi, Masaki; Kitazawa, Sin-iti; Ogawa, Hiroaki; Kawano, Yasunori; Itami, Kiyoshi; Ota, Kazuya; Hashimoto, Yasunori; Nakamura, Kitaru; Sugie, Tatsuo

2016-01-01

There is a need to develop ITER instrumentation and control (I and C) systems with high reliabilities. Interlock systems that activate machine protection functions are implemented on robust wired-logic systems such as programmable logic controllers (PLCs). We herein propose a software tool that generates program code templates for the control systems using PLC logic. This tool decreases careless mistakes by developers and increases reliability of the program codes. A large-scale engineering database has been implemented in the ITER project. To derive useful information from this database, we propose adding semantic data to it using the Resource Description Framework format. In our novel proposal for the ITER diagnostic control system, a guide words generator that analyzes the engineering data by inference is applied to the hazard and operability study. We validated the methods proposed in this paper by applying them to the preliminary design for the I and C system of the ITER edge Thomson scattering system. (author)

An optimal control method for fluid structure interaction systems via adjoint boundary pressure

Science.gov (United States)

Chirco, L.; Da Vià, R.; Manservisi, S.

2017-11-01

In recent year, in spite of the computational complexity, Fluid-structure interaction (FSI) problems have been widely studied due to their applicability in science and engineering. Fluid-structure interaction systems consist of one or more solid structures that deform by interacting with a surrounding fluid flow. FSI simulations evaluate the tensional state of the mechanical component and take into account the effects of the solid deformations on the motion of the interior fluids. The inverse FSI problem can be described as the achievement of a certain objective by changing some design parameters such as forces, boundary conditions and geometrical domain shapes. In this paper we would like to study the inverse FSI problem by using an optimal control approach. In particular we propose a pressure boundary optimal control method based on Lagrangian multipliers and adjoint variables. The objective is the minimization of a solid domain displacement matching functional obtained by finding the optimal pressure on the inlet boundary. The optimality system is derived from the first order necessary conditions by taking the Fréchet derivatives of the Lagrangian with respect to all the variables involved. The optimal solution is then obtained through a standard steepest descent algorithm applied to the optimality system. The approach presented in this work is general and could be used to assess other objective functionals and controls. In order to support the proposed approach we perform a few numerical tests where the fluid pressure on the domain inlet controls the displacement that occurs in a well defined region of the solid domain.

Optimal Control via Integrating the Dynamics of Magnetorheological Dampers and Structures

Directory of Open Access Journals (Sweden)

Amir Fayezioghani

2015-03-01

Full Text Available Magnetorheological (MR dampers have the advantage of being tuned by low voltages. This has attracted many researchers to develop semi-active control of structures in theory and practice. Most of the control strategies first obtain the desired forces of dampers without taking their dynamics into consideration and then determine the input voltages according to those forces. As a result, these strategies may face situations where the desired forces cannot be produced by the dampers. In this article, by integrating the equations of the dynamics of MR dampers and the structural motion, and solving them in one set, a more concise semi-active optimal control strategy is presented, so as to bypass the aforementioned drawback. Next, a strong database that can be utilized to form a controller for more realistic implementations is produced. As an illustrative example, the optimal voltages of the dampers of a six-storey shear building are obtained under the scaled El-Centro earthquake and used to train a set of integrated analysis-adaptive neuro-fuzzy inference systems (ANFISs as a controller. Results show that the overall performance of the proposed strategy is higher than most of the other conventional methods.

Active vibration control of a cylindrical structure using flexible piezoactuators: experimental work in air and water environments

International Nuclear Information System (INIS)

Sohn, Jung Woo; Choi, Seung-Bok

2014-01-01

In the present work, the modal characteristics and vibration control performance of a cylindrical structure in air and water are experimentally investigated, and the results are presented in time and frequency domains. In order to achieve this goal, an end-capped cylindrical shell structure is considered as a host structure, and MFC (macro fiber composite) actuators, which are flexible, are bonded on the surface of the structure. After manufacturing a cylindrical shell structure with aluminum, a modal test is carried out, and the natural frequencies of the proposed structure are obtained and analyzed. To verify the modal test results, a finite element analysis is also performed, and the results are compared with the modal test results. By using the experimentally obtained modal characteristics, a state space control model is established. An optimal controller is then designed in order to control the unwanted vibration and is experimentally realized. It has been shown that the structural vibration can be effectively decreased with the optimal control methodology in both air and water environmental conditions. (technical note)

Variable Structure Disturbance Rejection Control for Nonlinear Uncertain Systems with State and Control Delays via Optimal Sliding Mode Surface Approach

Directory of Open Access Journals (Sweden)

Jing Lei

2013-01-01

Full Text Available The paper considers the problem of variable structure control for nonlinear systems with uncertainty and time delays under persistent disturbance by using the optimal sliding mode surface approach. Through functional transformation, the original time-delay system is transformed into a delay-free one. The approximating sequence method is applied to solve the nonlinear optimal sliding mode surface problem which is reduced to a linear two-point boundary value problem of approximating sequences. The optimal sliding mode surface is obtained from the convergent solutions by solving a Riccati equation, a Sylvester equation, and the state and adjoint vector differential equations of approximating sequences. Then, the variable structure disturbance rejection control is presented by adopting an exponential trending law, where the state and control memory terms are designed to compensate the state and control delays, a feedforward control term is designed to reject the disturbance, and an adjoint compensator is designed to compensate the effects generated by the nonlinearity and the uncertainty. Furthermore, an observer is constructed to make the feedforward term physically realizable, and thus the dynamical observer-based dynamical variable structure disturbance rejection control law is produced. Finally, simulations are demonstrated to verify the effectiveness of the presented controller and the simplicity of the proposed approach.

Ownership and Control Structures, Corporate Governance and Income Smoothing in Brazil

Directory of Open Access Journals (Sweden)

Damiana Torres

2010-01-01

Full Text Available This article examines the association between the ownership and control structure, level of corporate governance and origin of capital (foreign or domestic of Brazilian companies on their propensity to smooth income. Using a sample of nonancialrms with shares traded on the São Paulo Stock Exchange (Bovespa at the end of 2007, we performed covariance analysis based on data from the preceding ten years, where the dependent variable was the index proposed by Eckel, an empirical proxy for smoothing. The results indicate that the more concentrated the shareholding and control structures of Brazilianrms are, both according to overall capital and voting capital, the more intensely they tend to smooth earnings to favor the interests of the majority shareholder. The results also show that this effect is less pronounced forrms with enhanced corporate governance levels and those with foreign capital.

DC Voltage Droop Control Structures and its Impact on the Interaction Modes in Interconnected AC-HVDC Systems

DEFF Research Database (Denmark)

Thams, Florian; Chatzivasileiadis, Spyros; Eriksson, Robert

2017-01-01

Different dc voltage droop control structures for future multi-terminal HVDC systems have been proposed in literature. This paper contributes to the evaluation of those structures by an analysis of their impact on the coupling of the interconnected subsystems. In particular, the modes...... of the systems are classified in different subsets according to the participation of the various subsystems. Those subsets are then evaluated qualitatively and quantitatively indicating which impact the choice of the droop control structure has on the degree of coupling between the connected ac and dc systems...

Towards structural controllability of local-world networks

International Nuclear Information System (INIS)

Sun, Shiwen; Ma, Yilin; Wu, Yafang; Wang, Li; Xia, Chengyi

2016-01-01

Controlling complex networks is of vital importance in science and engineering. Meanwhile, local-world effect is an important ingredient which should be taken into consideration in the complete description of real-world complex systems. In this letter, structural controllability of a class of local-world networks is investigated. Through extensive numerical simulations, firstly, effects of local world size M and network size N on structural controllability are examined. For local-world networks with sparse topological configuration, compared to network size, local-world size can induce stronger influence on controllability, however, for dense networks, controllability is greatly affected by network size and local-world effect can be neglected. Secondly, relationships between controllability and topological properties are analyzed. Lastly, the robustness of local-world networks under targeted attacks regarding structural controllability is discussed. These results can help to deepen the understanding of structural complexity and connectivity patterns of complex systems. - Highlights: • Structural controllability of a class of local-world networks is investigated. • For sparse local-world networks, compared to network size, local-world size can bring stronger influence on controllability. • For dense networks, controllability is greatly affected by network size and the effect of local-world size can be neglected. • Structural controllability against targeted node attacks is discussed.

Towards structural controllability of local-world networks

Energy Technology Data Exchange (ETDEWEB)

Sun, Shiwen, E-mail: sunsw80@126.com [Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Computer Vision and System (Tianjin University of Technology), Ministry of Education, Tianjin 300384 (China); Ma, Yilin; Wu, Yafang; Wang, Li; Xia, Chengyi [Tianjin Key Laboratory of Intelligence Computing and Novel Software Technology, Tianjin University of Technology, Tianjin 300384 (China); Key Laboratory of Computer Vision and System (Tianjin University of Technology), Ministry of Education, Tianjin 300384 (China)

2016-05-20

Controlling complex networks is of vital importance in science and engineering. Meanwhile, local-world effect is an important ingredient which should be taken into consideration in the complete description of real-world complex systems. In this letter, structural controllability of a class of local-world networks is investigated. Through extensive numerical simulations, firstly, effects of local world size M and network size N on structural controllability are examined. For local-world networks with sparse topological configuration, compared to network size, local-world size can induce stronger influence on controllability, however, for dense networks, controllability is greatly affected by network size and local-world effect can be neglected. Secondly, relationships between controllability and topological properties are analyzed. Lastly, the robustness of local-world networks under targeted attacks regarding structural controllability is discussed. These results can help to deepen the understanding of structural complexity and connectivity patterns of complex systems. - Highlights: • Structural controllability of a class of local-world networks is investigated. • For sparse local-world networks, compared to network size, local-world size can bring stronger influence on controllability. • For dense networks, controllability is greatly affected by network size and the effect of local-world size can be neglected. • Structural controllability against targeted node attacks is discussed.

Indirect control and power in mutual control structures

NARCIS (Netherlands)

Karos, D.; Peters, H.J.M.

2013-01-01

In a mutual control structure agents exercise control over each other. Typical examples occur in the area of corporate governance: firms and investment companies exercise mutual control, in particular by owning each others’ stocks. In this paper we formulate a general model for such situations.

Real-time monitoring and structural control of a wind turbine using a rocking system

DEFF Research Database (Denmark)

Caterino, Nicola; Spizzuoco, Mariacristina; Georgakis, Christos T.

2016-01-01

The design of a semi-active (SA) control system to mitigate wind induced structural demand to high wind turbine towers is discussed herein. A variable restraint at the base, able to modify in real time its mechanical properties according to the instantaneous response of the tower, is proposed...

Model reduction in integrated controls-structures design

Science.gov (United States)

Maghami, Peiman G.

1993-01-01

It is the objective of this paper to present a model reduction technique developed for the integrated controls-structures design of flexible structures. Integrated controls-structures design problems are typically posed as nonlinear mathematical programming problems, where the design variables consist of both structural and control parameters. In the solution process, both structural and control design variables are constantly changing; therefore, the dynamic characteristics of the structure are also changing. This presents a problem in obtaining a reduced-order model for active control design and analysis which will be valid for all design points within the design space. In other words, the frequency and number of the significant modes of the structure (modes that should be included) may vary considerably throughout the design process. This is also true as the locations and/or masses of the sensors and actuators change. Moreover, since the number of design evaluations in the integrated design process could easily run into thousands, any feasible order-reduction method should not require model reduction analysis at every design iteration. In this paper a novel and efficient technique for model reduction in the integrated controls-structures design process, which addresses these issues, is presented.

Structural controllability and controlling centrality of temporal networks.

Science.gov (United States)

Pan, Yujian; Li, Xiang

2014-01-01

Temporal networks are such networks where nodes and interactions may appear and disappear at various time scales. With the evidence of ubiquity of temporal networks in our economy, nature and society, it's urgent and significant to focus on its structural controllability as well as the corresponding characteristics, which nowadays is still an untouched topic. We develop graphic tools to study the structural controllability as well as its characteristics, identifying the intrinsic mechanism of the ability of individuals in controlling a dynamic and large-scale temporal network. Classifying temporal trees of a temporal network into different types, we give (both upper and lower) analytical bounds of the controlling centrality, which are verified by numerical simulations of both artificial and empirical temporal networks. We find that the positive relationship between aggregated degree and controlling centrality as well as the scale-free distribution of node's controlling centrality are virtually independent of the time scale and types of datasets, meaning the inherent robustness and heterogeneity of the controlling centrality of nodes within temporal networks.

75 FR 45572 - Oil Pollution Prevention; Spill Prevention, Control, and Countermeasure (SPCC) Rule-Proposed...

Science.gov (United States)

2010-08-03

... Oil Pollution Prevention; Spill Prevention, Control, and Countermeasure (SPCC) Rule--Proposed... Federal Regulations is proposed to be amended as follows: PART 112--OIL POLLUTION PREVENTION 1. The... certain facilities must prepare or amend their Spill Prevention, Control, and Countermeasure (SPCC) Plans...

Pinning Control Strategy of Multicommunity Structure Networks

Directory of Open Access Journals (Sweden)

Chao Ding

2017-01-01

Full Text Available In order to investigate the effects of community structure on synchronization, a pinning control strategy is researched in a class of complex networks with community structure in this paper. A feedback control law is designed based on the network community structure information. The stability condition is given and proved by using Lyapunov stability theory. Our research shows that as to community structure networks, there being a threshold hT≈5, when coupling strength bellows this threshold, the stronger coupling strength corresponds to higher synchronizability; vice versa, the stronger coupling strength brings lower synchronizability. In addition the synchronizability of overlapping and nonoverlapping community structure networks was simulated and analyzed; while the nodes were controlled randomly and intensively, the results show that intensive control strategy is better than the random one. The network will reach synchronization easily when the node with largest betweenness was controlled. Furthermore, four difference networks’ synchronizability, such as Barabási-Albert network, Watts-Strogatz network, Erdös-Rényi network, and community structure network, are simulated; the research shows that the community structure network is more easily synchronized under the same control strength.

Optimal resonant control of flexible structures

DEFF Research Database (Denmark)

Krenk, Steen; Høgsberg, Jan Becker

2009-01-01

When introducing a resonant controller for a particular vibration mode in a structure this mode splits into two. A design principle is developed for resonant control based oil equal damping of these two modes. First the design principle is developed for control of a system with a single degree...... of freedom, and then it is extended to multi-mode structures. A root locus analysis of the controlled single-mode structure identifies the equal modal damping property as a condition oil the linear and Cubic terms of the characteristic equation. Particular solutions for filtered displacement feedback...... and filtered acceleration feedback are developed by combining the root locus analysis with optimal properties of the displacement amplification frequency curve. The results are then extended to multi-mode structures by including a quasi-static representation of the background modes in the equations...

Real Time Implementation of Incremental Fuzzy Logic Controller for Gas Pipeline Corrosion Control

Directory of Open Access Journals (Sweden)

Gopalakrishnan Jayapalan

2014-01-01

Full Text Available A robust virtual instrumentation based fuzzy incremental corrosion controller is presented to protect metallic gas pipelines. Controller output depends on error and change in error of the controlled variable. For corrosion control purpose pipe to soil potential is considered as process variable. The proposed fuzzy incremental controller is designed using a very simple control rule base and the most natural and unbiased membership functions. The proposed scheme is tested for a wide range of pipe to soil potential control. Performance comparison between the conventional proportional integral type and proposed fuzzy incremental controller is made in terms of several performance criteria such as peak overshoot, settling time, and rise time. Result shows that the proposed controller outperforms its conventional counterpart in each case. Designed controller can be taken in automode without waiting for initial polarization to stabilize. Initial startup curve of proportional integral controller and fuzzy incremental controller is reported. This controller can be used to protect any metallic structures such as pipelines, tanks, concrete structures, ship, and offshore structures.

Teaching the foundations of quantum mechanics in secondary school: a proposed conceptual structure

Directory of Open Access Journals (Sweden)

Maria de los Angeles Fanaro

2009-03-01

Full Text Available This paper is part of a doctoral thesis that investigates Basic Quantum Mechanics (QM teaching in high school. A Conceptual Structure of Reference (CSR based on the Path Integral Method of Feynman (1965 was rebuilt and a Proposed Conceptual Structure for Teaching (PCST (Otero, 2006, 2007 the basics of Quantum Mechanics at secondary school was designed, analysed and carried out. This PCST does not follow the historical route and it is complementary to the canonical formalism. The concepts: probability distribution, quantum system, x(t alternative, amplitude of probability, sum of probability amplitude, action, Planck's constant, and classic-quantum transition were rebuilt with the students. Mathematical formalism was avoided by using simulation software assistance. The Proposed Conceptual Structure for Teaching (PCST is described and some results from the test carried out by the class group are discussed. This information allows the analysis of the Conceptual Structure Effectively Reconstructed (CSER to be initiated with the students.

Additional operations in algebra of structural numbers for control algorithm development

Directory of Open Access Journals (Sweden)

Morhun A.V.

2016-12-01

Full Text Available The structural numbers and the algebra of the structural numbers due to the simplicity of representation, flexibility and current algebraic operations are the powerful tool for a wide range of applications. In autonomous power supply systems and systems with distributed generation (Micro Grid mathematical apparatus of structural numbers can be effectively used for the calculation of the parameters of the operating modes of consumption of electric energy. The purpose of the article is the representation of the additional algebra of structural numbers. The standard algebra was proposed to be extended by the additional operations and modification current in order to expand the scope of their use, namely to construct a flexible, adaptive algorithms of control systems. It is achieved due to the possibility to consider each individual component of the system with its parameters and provide easy management of entire system and each individual component. Thus, structural numbers and extended algebra are the perspective line of research and further studying is required.

Fluid control structures in microfluidic devices

Science.gov (United States)

Mathies, Richard A.; Grover, William H.; Skelley, Alison; Lagally, Eric; Liu, Chung N.

2017-05-09

Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.

Structure observation of single solidified droplet by in situ controllable quenching based on nanocalorimetry

International Nuclear Information System (INIS)

Zhao, Bingge; Li, Linfang; Yang, Bin; Yan, Ming; Zhai, Qijie; Gao, Yulai

2013-01-01

Highlights: •Controllable quenching rate up to 15,000 K/s was realized by FSC. •FSC sample was novelly characterized by FIB and HRTEM. •Solidification structure with undercooling of 110.9 K was investigated. •This study opens a new approach in rapid solidification and FSC measurement. -- Abstract: Fast scanning calorimetry (FSC) based on nanocalorimetry and thin film technique is a newly developed attractive tool to investigate the solidification behavior of single droplet by in situ controllable ultrafast cooling. In this paper, we introduced this novel technique to in situ control the quenching of single Sn3.5Ag metallic droplet at cooling rate up to 15,000 K/s with corresponding undercooling of 110.9 K. In particular, the solidification structure of this real time quenched single droplet was observed and analyzed with focused ion beam (FIB), scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). This research proposed a new approach to research the solidification structure of single droplet with precisely controlled size and extreme cooling rate

Control of framed structures using intelligent monitoring networks

Directory of Open Access Journals (Sweden)

Foti Dora

2017-01-01

Full Text Available The paper proposes the integration of structural monitoring with Building Management Systems for electricity and gas distributions. To assess the state of damage of existing buildings the technics of Structural Health Monitoring (SHM is adopted. SHM as well as to record the occurrence of sudden structural damage resulting from exceptional events (earthquakes, explosions, shocks and collisions with vehicles, etc., allows the monitoring of the progressive damage and structural performance under operating conditions through the extraction of the modal parameters of the structure. This approach requires time to process acquired data that, depending on the size of the building and the number of monitored points, varies from minutes to hours. In this paper, an intelligent system is proposed to immediately communicate during an earthquake the overrun of a certain ground shaking threshold so that gas delivery and selected power loads are interrupted, as suggested by current national regulations on structures. The use of low-cost and reduced size accelerometric sensors integrated with Energy Monitoring Systems is proposed in both highrisk earthquake centers and in all “strategic” buildings that must ensure their operation use immediately after the earthquake. The procedure for calibrating the horizontal and vertical acceleration threshold is also sketched.

Event structure and cognitive control.

Science.gov (United States)

Reimer, Jason F; Radvansky, Gabriel A; Lorsbach, Thomas C; Armendarez, Joseph J

2015-09-01

Recently, a great deal of research has demonstrated that although everyday experience is continuous in nature, it is parsed into separate events. The aim of the present study was to examine whether event structure can influence the effectiveness of cognitive control. Across 5 experiments we varied the structure of events within the AX-CPT by shifting the spatial location of cues and probes on a computer screen. When location shifts were present, a pattern of AX-CPT performance consistent with enhanced cognitive control was found. To test whether the location shift effects were caused by the presence of event boundaries per se, other aspects of the AX-CPT were manipulated, such as the color of cues and probes and the inclusion of a distractor task during the cue-probe delay. Changes in cognitive control were not found under these conditions, suggesting that the location shift effects were specifically related to the formation of separate event models. Together, these results can be accounted for by the Event Horizon Model and a representation-based theory of cognitive control, and suggest that cognitive control can be influenced by the surrounding environmental structure. (c) 2015 APA, all rights reserved).

Implementation of programmable logic controller for proposed new instrumentation and control system of RTP

International Nuclear Information System (INIS)

Mohd Khairulezwan Abdul Manan; Mohd Idris Taib; Mohd Dzul Aiman Aslan

2010-01-01

Reactor Monitoring System is one of very important part of Reactor Instrumentation and Control system. Current monitoring system is using analog system whereby all circuits are discrete circuit and all displays and indicators are not digitalized. The proposed new system will use using a Commercial Off-The-Shelf, state of the art, Supervisory Control and Data Acquisition system such as Programmable Logic Controller as well as Computer System. The implementations of Programmable Logic Controller are used for Data Acquisition System and as a sub-system for Computer System where all the activities involved are stored for operation record and report as well as use for research purposes. Programmable Logic Controller receives galvanised or optically isolated signal from Reactor Protection System. Programmable Logic Controller also receives signal from other parameters as a digital and analog input related to reactor system. (author)

Control structures for high speed processors

Science.gov (United States)

Maki, G. K.; Mankin, R.; Owsley, P. A.; Kim, G. M.

1982-01-01

A special processor was designed to function as a Reed Solomon decoder with throughput data rate in the Mhz range. This data rate is significantly greater than is possible with conventional digital architectures. To achieve this rate, the processor design includes sequential, pipelined, distributed, and parallel processing. The processor was designed using a high level language register transfer language. The RTL can be used to describe how the different processes are implemented by the hardware. One problem of special interest was the development of dependent processes which are analogous to software subroutines. For greater flexibility, the RTL control structure was implemented in ROM. The special purpose hardware required approximately 1000 SSI and MSI components. The data rate throughput is 2.5 megabits/second. This data rate is achieved through the use of pipelined and distributed processing. This data rate can be compared with 800 kilobits/second in a recently proposed very large scale integration design of a Reed Solomon encoder.

Hemi-fused structure mediates and controls fusion and fission in live cells.

Science.gov (United States)

Zhao, Wei-Dong; Hamid, Edaeni; Shin, Wonchul; Wen, Peter J; Krystofiak, Evan S; Villarreal, Seth A; Chiang, Hsueh-Cheng; Kachar, Bechara; Wu, Ling-Gang

2016-06-23

Membrane fusion and fission are vital for eukaryotic life. For three decades, it has been proposed that fusion is mediated by fusion between the proximal leaflets of two bilayers (hemi-fusion) to produce a hemi-fused structure, followed by fusion between the distal leaflets, whereas fission is via hemi-fission, which also produces a hemi-fused structure, followed by full fission. This hypothesis remained unsupported owing to the lack of observation of hemi-fusion or hemi-fission in live cells. A competing fusion hypothesis involving protein-lined pore formation has also been proposed. Here we report the observation of a hemi-fused Ω-shaped structure in live neuroendocrine chromaffin cells and pancreatic β-cells, visualized using confocal and super-resolution stimulated emission depletion microscopy. This structure is generated from fusion pore opening or closure (fission) at the plasma membrane. Unexpectedly, the transition to full fusion or fission is determined by competition between fusion and calcium/dynamin-dependent fission mechanisms, and is notably slow (seconds to tens of seconds) in a substantial fraction of the events. These results provide key missing evidence in support of the hemi-fusion and hemi-fission hypothesis in live cells, and reveal the hemi-fused intermediate as a key structure controlling fusion and fission, as fusion and fission mechanisms compete to determine the transition to fusion or fission.

Sustainability on the urban scale: Proposal of a structure of indicators for the Spanish context

Energy Technology Data Exchange (ETDEWEB)

Braulio-Gonzalo, Marta, E-mail: braulio@uji.es; Bovea, María Dolores, E-mail: bovea@uji.es; Ruá, María José, E-mail: rua@uji.es

2015-07-15

Some efforts to assess sustainability on the urban scale have been made and different tools for measuring the impact on and caused by cities have emerged. However, the sustainability concept varies from region to region, and indicators to measure it should be suitable for the context-specific conditions of the region under study. After doing a comprehensive review of the indicators included in 13 tools developed to assess urban sustainability of cities, this article proposes a new structure of indicators adapted to a Mediterranean city in Spain. The proposed structure is based on a two-level scheme that consists in 14 categories and 63 subcategories, which agglutinate urban sustainability indicators according to their purpose. This structure suggests a set of comprehensible qualitative and quantitative indicators that are easily applicable on neighbourhood or city scales. Given the similar features of Mediterranean countries in terms of environmental and socio-economic aspects, the proposed structure could be extrapolated to other countries with climatic and cultural similarities. Otherwise, the system is a useful tool in the decision-making process to help the different stakeholders involved in new urban developments and regeneration projects in existing neighbourhoods, such as developers, urban planners and public administrations. - Highlights: • Comprehensive review of 13 urban sustainability assessment tools • Proposal of a two-level structure to cluster urban sustainability indicators • Inclusion of sustainability criteria for urban planning projects and interventions.

Sustainability on the urban scale: Proposal of a structure of indicators for the Spanish context

International Nuclear Information System (INIS)

Braulio-Gonzalo, Marta; Bovea, María Dolores; Ruá, María José

2015-01-01

Some efforts to assess sustainability on the urban scale have been made and different tools for measuring the impact on and caused by cities have emerged. However, the sustainability concept varies from region to region, and indicators to measure it should be suitable for the context-specific conditions of the region under study. After doing a comprehensive review of the indicators included in 13 tools developed to assess urban sustainability of cities, this article proposes a new structure of indicators adapted to a Mediterranean city in Spain. The proposed structure is based on a two-level scheme that consists in 14 categories and 63 subcategories, which agglutinate urban sustainability indicators according to their purpose. This structure suggests a set of comprehensible qualitative and quantitative indicators that are easily applicable on neighbourhood or city scales. Given the similar features of Mediterranean countries in terms of environmental and socio-economic aspects, the proposed structure could be extrapolated to other countries with climatic and cultural similarities. Otherwise, the system is a useful tool in the decision-making process to help the different stakeholders involved in new urban developments and regeneration projects in existing neighbourhoods, such as developers, urban planners and public administrations. - Highlights: • Comprehensive review of 13 urban sustainability assessment tools • Proposal of a two-level structure to cluster urban sustainability indicators • Inclusion of sustainability criteria for urban planning projects and interventions

Proposed use of the radio-frequency quadrupole structure to funnel high-current ion beams

International Nuclear Information System (INIS)

Stokes, R.H.; Minerbo, G.N.

1985-01-01

In this paper, we describe a new approach to funneling beams that are initially accelerated in two radio-frequency quadrupole (RFQ) accelerators. Instead of discrete optical elements, we propose to funnel within an RFQ structure, so that during the funneling process the beam is always confined by periodic transverse focusing. Beams with high space charge experience irreversible emittance growth when they emerge from a periodic focusing system. To alleviate this problem, in the proposed funneling system it should be possible to maintain the same focusing periodicity as that of the accelerators preceding the funnel. Also, instead of conventional deflection systems, we propose to use the properties of a modified RFQ structure to deflect two parallel beams toward each other and to merge them into a single final beam. 1 ref., 3 figs

Control structure design for resource recovery using the enhanced biological phosphorus removal and recovery (EBP2R) activated sludge process

DEFF Research Database (Denmark)

Valverde Perez, Borja; Fuentes-Martínez, José Manuel; Flores Alsina, Xavier

2016-01-01

, it is concluded that the SBR is the most effective reactor configuration for the EBP2R process. Importantly, the designed control structures rely on control loops that do not require chemical dosing for nutrient management, thereby reducing the environmental footprint of the EBP2R process. The proposed control...

A broadband frequency-tunable dynamic absorber for the vibration control of structures

International Nuclear Information System (INIS)

Komatsuzaki, T; Inoue, T; Terashima, O

2016-01-01

A passive-type dynamic vibration absorber (DVA) is basically a mass-spring system that suppresses the vibration of a structure at a particular frequency. Since the natural frequency of the DVA is usually tuned to a frequency of particular excitation, the DVA is especially effective when the excitation frequency is close to the natural frequency of the structure. Fixing the physical properties of the DVA limits the application to a narrowband, harmonically excited vibration problem. A frequency-tunable DVA that can modulate its stiffness provides adaptability to the vibration control device against non-stationary disturbances. In this paper, we suggest a broadband frequency-tunable DVA whose natural frequency can be extended by 300% to the nominal value using the magnetorheological elastomers (MREs). The frequency adjustability of the proposed absorber is first shown. The real-time vibration control performance of the frequency-tunable absorber for an acoustically excited plate having multiple resonant peaks is then evaluated. Investigations show that the vibration of the structure can be effectively reduced with an improved performance by the DVA in comparison to the conventional passive- type absorber. (paper)

Flexible Structure Control Scheme of a UAVs Formation to Improve the Formation Stability During Maneuvers

Directory of Open Access Journals (Sweden)

Kownacki Cezary

2017-09-01

Full Text Available One of the issues related to formation flights, which requires to be still discussed, is the stability of formation flight in turns, where the aerodynamic conditions can be substantially different for outer vehicles due to varying bank angles. Therefore, this paper proposes a decentralized control algorithm based on a leader as the reference point for followers, i.e. other UAVs and two flocking behaviors responsible for local position control, i.e. cohesion and repulsion. But opposite to other research in this area, the structure of the formation becomes flexible (structure is being reshaped and bent according to actual turn radius of the leader. During turns the structure is bent basing on concentred circles with different radiuses corresponding to relative locations of vehicles in the structure. Simultaneously, UAVs' air-speeds must be modified according to the length of turn radius to achieve the stability of the structure. The effectiveness of the algorithm is verified by the results of simulated flights of five UAVs.

Carbon Structure Hazard Control

Science.gov (United States)

Yoder, Tommy; Greene, Ben; Porter, Alan

2015-01-01

Carbon composite structures are widely used in virtually all advanced technology industries for a multitude of applications. The high strength-to-weight ratio and resistance to aggressive service environments make them highly desirable. Automotive, aerospace, and petroleum industries extensively use, and will continue to use, this enabling technology. As a result of this broad range of use, field and test personnel are increasingly exposed to hazards associated with these structures. No single published document exists to address the hazards and make recommendations for the hazard controls required for the different exposure possibilities from damaged structures including airborne fibers, fly, and dust. The potential for personnel exposure varies depending on the application or manipulation of the structure. The effect of exposure to carbon hazards is not limited to personnel, protection of electronics and mechanical equipment must be considered as well. The various exposure opportunities defined in this document include pre-manufacturing fly and dust, the cured structure, manufacturing/machining, post-event cleanup, and post-event test and/or evaluation. Hazard control is defined as it is applicable or applied for the specific exposure opportunity. The carbon exposure hazard includes fly, dust, fiber (cured/uncured), and matrix vapor/thermal decomposition products. By using the recommendations in this document, a high level of confidence can be assured for the protection of personnel and equipment.

Active and passive vibration control of structures

CERN Document Server

Spelsberg-Korspeter, Gottfried

2014-01-01

Active and Passive Vibration Control of Structures form an issue of very actual interest in many different fields of engineering, for example in the automotive and aerospace industry, in precision engineering (e.g. in large telescopes), and also in civil engineering. The papers in this volume bring together engineers of different background, and it fill gaps between structural mechanics, vibrations and modern control theory.  Also links between the different applications in structural control are shown.

Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

Science.gov (United States)

Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

2008-01-01

The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

76 FR 49769 - Proposed Agency Information Collection Activities; Comment Request

Science.gov (United States)

2011-08-11

... in Organizational Structure. Agency form number: FR Y-10E. OMB control number: 7100-0297. Frequency... OMB control numbers to collection of information requests and requirements conducted or sponsored by... control number. Request for Comment on Information Collection Proposal The following information...

[New idea of traditional Chinese medicine quality control based on "composition structure" theory].

Science.gov (United States)

Liu, Dan; Jia, Xiaobin; Yu, Danhong

2012-03-01

On the road of the modern Chinese medicine developing internationally, there is a key issues that setting up a reasonable, accurate and be quantified quality evaluation system which is comply with the basic theory of Chinese medicine. Based on the overall understanding of the role of traditional Chinese medicine components, author suggested that the idea of "structural components" theory should be embedded into the system and thought the Chinese medicine play a multi-target, multi-channel pharmacodynamic effects founded on the specific microcosmic structural relationship between the components and the components within the group. At present, the way of Chinese pharmacopoeia checking the quality of Chinese medicine is mainly depends on controlling the single or multiple targets of ingredients. In fact, this way is out of the overall effectiveness of the Chinese medicine, so we can not thoroughly controlling the quality of Chinese medicine from the essence of the Chinese medicine. Secondly, it's only macro-structural quantity that the Chinese pharmacopoeia just controlling the less effective ingredients, this is not enough to reflect the internal microstructure of the integrity and systematic. In other words, this cannot reflect the structural components of the Chinese medicine (the essence of traditional Chinese medicine). In view of above mentioned reasons, the author propose the new idea on the quality control in the medicine that quantify the ratio structural relationship in component and the ingredients of the components, set the optimal controlling proportion between the components and ingredients. At the same time, author thought we should conduct the depth study in the micro-quantified the multi-component and multi-ingredient, in the process of studying the material basis of Chinese medicine. Therefore, it could establish a more rational basis for the Chinese medicine quality controlling system.

Vibration control of active structures an introduction

CERN Document Server

Preumont, Andre

2002-01-01

This text is an introduction to the dynamics of active structures and to the feedback control of lightly damped flexible structures. The emphasis is placed on basic issues and simple control strategies that work.

Fuzzy sliding mode controller of a pneumatic active isolating system using negative stiffness structure

International Nuclear Information System (INIS)

Le, Thanh Danh; Ahn, Kyoung Kwan

2012-01-01

A novel active vibration isolation system using negative stiffness structure (active system with NSS) for low excitation frequency ranges (< 5 Hz) is developed successfully. Here, the negative stiffness structure (NSS) is used to minimize the attraction of vibration. Then, the fuzzy sliding mode controller (FSMC) is designed to improve the vibration isolation performance of the active system with NSS. Based on Lyapunov stability theorem, the fuzzy control rules are constructed. Next, the experimental apparatus is built for evaluating the isolation efficiency of the proposed system controlled by the FSMC corresponding to various excitation conditions. In addition, the isolation performance of the active system with NSS, the active system without NSS and the passive the system with NSS is compared. The experimental results confirmed that the active system with NSS gives better isolation efficiency than the active system without NSS and the passive system with NSS in low excitation frequency areas

Mapping the coverage of security controls in cyber insurance proposal forms

OpenAIRE

Woods, D; Agrafiotis, I; Nurse, JRC; Creese, S

2017-01-01

Policy discussions often assume that wider adoption of cyber insurance will promote information security best practice. However, this depends on the process that applicants need to go through to apply for cyber insurance. A typical process would require an applicant to fill out a proposal form, which is a self-assessed questionnaire. In this paper, we examine 24 proposal forms, offered by insurers based in the UK and the US, to determine which security controls are present in the ...

Active control of noise radiation from vibrating structures

DEFF Research Database (Denmark)

Mørkholt, Jakob

developed, based on the theory of radiation filters for estimating the sound radiation from multimodal vibrations. This model has then been used in simulations of optimal feedback control, with special emphasis of the stability margins of the optimal control scheme. Two different methods of designing...... optimal and robust discrete-time feedback controllers for active vibration control of multimodal structures have been compared. They have been showed to yield controllers with identical frequency response characteristics, even though they employ completely different methods of numerical solutions...... and result in different representations of the controllers. The Internal Model Control structure combined with optimal filtering is suggested as an alternative to state space optimal control techniques for designing robust optimal controllers for audio frequency vibration control of resonant structures....

Proposed Objective Odor Control Test Methodology for Waste Containment

Science.gov (United States)

Vos, Gordon

2010-01-01

The Orion Cockpit Working Group has requested that an odor control testing methodology be proposed to evaluate the odor containment effectiveness of waste disposal bags to be flown on the Orion Crew Exploration Vehicle. As a standardized "odor containment" test does not appear to be a matter of record for the project, a new test method is being proposed. This method is based on existing test methods used in industrial hygiene for the evaluation of respirator fit in occupational settings, and takes into consideration peer reviewed documentation of human odor thresholds for standardized contaminates, industry stardnard atmostpheric testing methodologies, and established criteria for laboratory analysis. The proposed methodology is quantitative, though it can readily be complimented with a qualitative subjective assessment. Isoamyl acetate (IAA - also known at isopentyl acetate) is commonly used in respirator fit testing, and there are documented methodologies for both measuring its quantitative airborne concentrations. IAA is a clear, colorless liquid with a banana-like odor, documented detectable smell threshold for humans of 0.025 PPM, and a 15 PPB level of quantation limit.

Enhancing sediment flux control and natural hazard risk mitigation through a structured conceptual planning approach

Science.gov (United States)

Simoni, S.; Vignoli, G.; Mazzorana, B.

2017-08-01

Sediment fluxes from mountain rivers contribute to shape the geomorphologic features of lowland rivers and to establish the physical basis for an optimal set of ecosystem functions and related services to people. Through significant public funding, the hydro-morphological regimes of mountain rivers in the European Alps have been progressively altered over the last century, with the aim to provide a safe dwelling space, to boost transport, mobility and to support economic growth. We claim that the underlying planning weaknesses contribute to determine these inefficient resource allocations, since flood risk is still high and the ecosystem services are far from being optimal. Hence, with the overall aim to enhance sediment flux control and hazard risk mitigation in such heavily modified alpine streams, we propose a structured design workflow which guides the planner through system analysis and synthesis. As a first step the proposed workflow sets the relevant planning goals and assesses the protection structure functionality. Then a methodology is proposed to achieve the goals. This methodology consists in characterising the hydrologic basin of interest and the sediment availability and determining the sediment connectivity to channels. The focus is set on the detailed analysis of existing river cross sections where the sediment continuity is interrupted (e.g. slit and check dams). By retaining relevant sediment volumes these structures prevent the reactivation of hydro-morphological and associated ecological functionalities. Since their actual performance can be unsatisfying with respect to flood risk mitigation (e.g. mainly old structures), we introduce specific efficiency indicators as a support for the conceptual design stage to quantify effects related to sediment flux control and risk management. The proposed planning approach is then applied to the Gadria system (stream, slit dam, retention basin and culvert), located in South Tyrol, Italy. This case study

Control of chaotic oscillators via a class of model free active controller: Suppresion and synchronization

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Lopez, Ricardo [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana, Av. San Pablo No. 180, Reynosa-Tamaulipas, 02200, Azcapotzalco, Mexico D.F. (Mexico)], E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, Rafael [Departamento de Control Automatico, CINVESTAV-IPN, Apartado Postal 14-740, 07360 Mexico D.F. (Mexico)], E-mail: rguerra@ctrl.cinvestav.mx

2008-10-15

The goal of this work is related with the control of chaotic oscillators for chaos suppression and synchronization purposes. The proposed methodology is related with a class of robust active control (RAC) law, where the stabilizing part of the control structure is related with an integral high order sliding-mode and proportional form of the so-called control error. The proposed controller is applied to chaos suppression, synchronization and anti-synchronization tasks for nonlinear oscillators with different order and structure. Numerical experiments illustrate the satisfactory performance of the proposed methodology, when it is applied to Duffing and Chen oscillators.

Control of chaotic oscillators via a class of model free active controller: Suppresion and synchronization

International Nuclear Information System (INIS)

Aguilar-Lopez, Ricardo; Martinez-Guerra, Rafael

2008-01-01

The goal of this work is related with the control of chaotic oscillators for chaos suppression and synchronization purposes. The proposed methodology is related with a class of robust active control (RAC) law, where the stabilizing part of the control structure is related with an integral high order sliding-mode and proportional form of the so-called control error. The proposed controller is applied to chaos suppression, synchronization and anti-synchronization tasks for nonlinear oscillators with different order and structure. Numerical experiments illustrate the satisfactory performance of the proposed methodology, when it is applied to Duffing and Chen oscillators

Aircraft Landing and Attitude Control Using Dynamic Matrix Control

Directory of Open Access Journals (Sweden)

George Cristian Calugaru

2017-06-01

Full Text Available This paper proposes a method for an efficient control of the aircraft landing and attitude through Dynamic Matrix Control. The idea of MPC structures used in aircraft control has been well established during the last few years, but some aspects require further investigation. With this in mind, the paper proposes structures for aircraft landing and aircraft attitude control by using single DMC controllers for landing and respectively one DMC controller for each of the attitude axis (pitch attitude hold, bank angle hold and heading hold. The model used for analysis of the aircraft landing structure is based on the last phase of landing. Also, the model used to illustrate the attitude control is that of a pitch attitude hold system of a N250-100 aircraft. Simulations are performed for a variety of control and prediction horizons, taking into account the possibility of adding a weighting factor for the control actions. Apart from separate studies on step reference variations, for some use cases, a generic reference trajectory is provided as a control purpose of the system. Results show a better performance of the proposed method in terms of control surface transition and protection of the actuators involved and a better time response in stabilizing the aircraft attitude. Overall, the aspects shown ensure an improved aircraft attitude control and landing stabilization.

A proposed GaAs-based superlattice solar cell structure with high efficiency and high radiation tolerance

Science.gov (United States)

Goradia, Chandra; Clark, Ralph; Brinker, David

1985-01-01

A solar cell structure is proposed which uses a GaAs nipi doping superlattice. An important feature of this structure is that photogenerated minority carriers are very quickly collected in a time shorter than bulk lifetime in the fairly heavily doped n and p layers and these carriers are then transported parallel to the superlattice layers to selective ohmic contacts. Assuming that these already-separated carriers have very long recombination lifetimes, due to their being across an indirect bandgap in real space, it is argued that the proposed structure may exhibit superior radiation tolerance along with reasonably high beginning-of-life efficiency.

The structure of control and data transfer management system for the GAMMA-400 scientific complex

International Nuclear Information System (INIS)

Arkhangelskiy, A I; Bobkov, S G; Serdin, O V; Gorbunov, M S; Topchiev, N P

2016-01-01

A description of the control and data transfer management system for scientific instrumentation involved in the GAMMA-400 space project is given. The technical capabilities of all specialized equipment to provide the functioning of the scientific instrumentation and satellite support systems are unified in a single structure. Control of the scientific instruments is maintained using one-time pulse radio commands, as well as program commands in the form of 16-bit code words, which are transmitted via onboard control system and scientific data acquisition system. Up to 100 GByte of data per day can be transferred to the ground segment of the project. The correctness of the proposed and implemented structure, engineering solutions and electronic elemental base selection has been verified by the experimental working-off of the prototype of the GAMMA-400 scientific complex in laboratory conditions. (paper)

Variable-Structure Control of a Model Glider Airplane

Science.gov (United States)

Waszak, Martin R.; Anderson, Mark R.

2008-01-01

A variable-structure control system designed to enable a fuselage-heavy airplane to recover from spin has been demonstrated in a hand-launched, instrumented model glider airplane. Variable-structure control is a high-speed switching feedback control technique that has been developed for control of nonlinear dynamic systems.

An investigation into the organisation and structural design of multi-computer process-control systems

International Nuclear Information System (INIS)

Gertenbach, W.P.

1981-12-01

A multi-computer system for the collection of data and control of distributed processes has been developed. The structure and organisation of this system, a study of the general theory of systems and of modularity was used as a basis for an investigation into the organisation and structured design of multi-computer process-control systems. A multi-dimensional model of multi-computer process-control systems was developed. In this model a strict separation was made between organisational properties of multi-computer process-control systems and implementation dependant properties. The model was based on the principles of hierarchical analysis and modularity. Several notions of hierarchy were found necessary to describe fully the organisation of multi-computer systems. A new concept, that of interconnection abstraction was identified. This concept is an extrapolation of implementation techniques in the hardware implementation area to the software implementation area. A synthesis procedure which relies heavily on the above described analysis of multi-computer process-control systems is proposed. The above mentioned model, and a set of performance factors which depend on a set of identified design criteria, were used to constrain the set of possible solutions to the multi-computer process-control system synthesis-procedure

75 FR 80066 - Quality Control Requirements for Direct Endorsement Lenders; Notice of Proposed Information...

Science.gov (United States)

2010-12-21

... DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT [Docket No. FR-5380-N-50] Quality Control Requirements... information: Title of Proposal: Quality Control Requirements for Direct Endorsement Lenders. OMB Control... a result, DE lenders will be responsible for conducting quality control on TPO originations of FHA...

Innovation in Active Vibration Control Strategy of Intelligent Structures

Directory of Open Access Journals (Sweden)

A. Moutsopoulou

2014-01-01

Full Text Available Large amplitudes and attenuating vibration periods result in fatigue, instability, and poor structural performance. In light of past approaches in this field, this paper intends to discuss some innovative approaches in vibration control of intelligent structures, particularly in the case of structures with embedded piezoelectric materials. Control strategies are presented, such as the linear quadratic control theory, as well as more advanced theories, such as robust control theory. The paper presents sufficiently a recognizable advance in knowledge of active vibration control in intelligent structures.

Structural Control Systems Implemented in Civil Engineering

Directory of Open Access Journals (Sweden)

Cristian Pastia

2005-01-01

Full Text Available Over the past three decades, a great interest has been generated by the use of protection systems to mitigate the effects of dynamic environmental hazards on civil engineering structures, such as earthquakes and strong wind. These control systems develop controllable forces to add or dissipate energy in a structure, or both, due to specific devices integrated with sensors, controllers and real – time process to operate. The paper includes the advantages of these technologies consisting of the following sections: 1 represents an introduction, 2 deals with passive control system, 3 regards some control techniques, 4 concerns hybrid control techniques, 5 contains semi – active control techniques, and 6 is dedicated to general conclusions.

Integrated seismic design of structure and control systems

CERN Document Server

Castaldo, Paolo

2014-01-01

The structural optimization procedure presented in this book makes it possible to achieve seismic protection through integrated structural/control system design. In particular, it is explained how slender structural systems with a high seismic performance can be achieved through inclusion of viscous and viscoelastic dampers as an integral part of the system. Readers are provided with essential introductory information on passive structural control and passive energy dissipation systems. Dynamic analyses of both single and multiple degree of freedom systems are performed in order to verify the achievement of pre-assigned performance targets, and it is explained how the optimal integrated design methodology, also relevant to retrofitting of existing buildings, should be applied. The book illustrates how structural control research is opening up new possibilities in structural forms and configurations without compromising structural performance.

Decentralized Networked Control of Building Structures

Czech Academy of Sciences Publication Activity Database

Bakule, Lubomír; Rehák, Branislav; Papík, Martin

2016-01-01

Roč. 31, č. 11 (2016), s. 871-886 ISSN 1093-9687 R&D Projects: GA ČR GA13-02149S Institutional support: RVO:67985556 Keywords : decentralized control * networked control * building structures Subject RIV: BC - Control Systems Theory Impact factor: 5.786, year: 2016

Bio-inspired passive actuator simulating an abalone shell mechanism for structural control

International Nuclear Information System (INIS)

Yang, Henry T Y; Lin, Chun-Hung; Bridges, Daniel; Randall, Connor J; Hansma, Paul K

2010-01-01

An energy dispersion mechanism called 'sacrificial bonds and hidden length', which is found in some biological systems, such as abalone shells and bones, is the inspiration for new strategies for structural control. Sacrificial bonds and hidden length can substantially increase the stiffness and enhance energy dissipation in the constituent molecules of abalone shells and bone. Having been inspired by the usefulness and effectiveness of such a mechanism, which has evolved over millions of years and countless cycles of evolutions, the authors employ the conceptual underpinnings of this mechanism to develop a bio-inspired passive actuator. This paper presents a fundamental method for optimally designing such bio-inspired passive actuators for structural control. To optimize the bio-inspired passive actuator, a simple method utilizing the force–displacement–velocity (FDV) plots based on LQR control is proposed. A linear regression approach is adopted in this research to find the initial values of the desired parameters for the bio-inspired passive actuator. The illustrative examples, conducted by numerical simulation with experimental validation, suggest that the bio-inspired passive actuator based on sacrificial bonds and hidden length may be comparable in performance to state-of-the-art semi-active actuators

Bio-inspired passive actuator simulating an abalone shell mechanism for structural control

Science.gov (United States)

Yang, Henry T. Y.; Lin, Chun-Hung; Bridges, Daniel; Randall, Connor J.; Hansma, Paul K.

2010-10-01

An energy dispersion mechanism called 'sacrificial bonds and hidden length', which is found in some biological systems, such as abalone shells and bones, is the inspiration for new strategies for structural control. Sacrificial bonds and hidden length can substantially increase the stiffness and enhance energy dissipation in the constituent molecules of abalone shells and bone. Having been inspired by the usefulness and effectiveness of such a mechanism, which has evolved over millions of years and countless cycles of evolutions, the authors employ the conceptual underpinnings of this mechanism to develop a bio-inspired passive actuator. This paper presents a fundamental method for optimally designing such bio-inspired passive actuators for structural control. To optimize the bio-inspired passive actuator, a simple method utilizing the force-displacement-velocity (FDV) plots based on LQR control is proposed. A linear regression approach is adopted in this research to find the initial values of the desired parameters for the bio-inspired passive actuator. The illustrative examples, conducted by numerical simulation with experimental validation, suggest that the bio-inspired passive actuator based on sacrificial bonds and hidden length may be comparable in performance to state-of-the-art semi-active actuators.

Chaos control via a simple fractional-order controller

International Nuclear Information System (INIS)

Tavazoei, Mohammad Saleh; Haeri, Mohammad

2008-01-01

In this Letter, we propose a fractional-order controller to stabilize the unstable fixed points of an unstable open-loop system. Also, we show that this controller has strong ability to eliminate chaotic oscillations or reduce them to regular oscillations in the chaotic systems. This controller has simple structure and is designed very easily. To determine the control parameters, one needs only a little knowledge about the plant and therefore, the proposed controller is a suitable choice in the control of uncertain chaotic systems

Integrating normal and abnormal personality structure: a proposal for DSM-V.

Science.gov (United States)

Widiger, Thomas A

2011-06-01

The personality disorders section of the American Psychiatric Association's fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) is currently being developed. The purpose of the current paper is to encourage the authors of DSM-V to integrate normal and abnormal personality structure within a common, integrative model, and to suggest that the optimal choice for such an integration would be the five-factor model (FFM) of general personality structure. A proposal for the classification of personality disorder from the perspective of the FFM is provided. Discussed as well are implications and issues associated with an FFM of personality disorder, including validity, coverage, feasibility, clinical utility, and treatment implications.

An optically controlled SiC lateral power transistor based on SiC/SiCGe super junction structure

International Nuclear Information System (INIS)

Pu Hongbin; Cao Lin; Ren Jie; Chen Zhiming; Nan Yagong

2010-01-01

An optically controlled SiC/SiCGe lateral power transistor based on superjunction structure has been proposed, in which n-SiCGe/p-SiC superjunction structure is employed to improve device figure of merit. Performance of the novel optically controlled power transistor was simulated using Silvaco Atlas tools, which has shown that the device has a very good response to the visible light and the near infrared light. The optoelectronic responsivities of the device at 0.5 μm and 0.7 μm are 330 mA/W and 76.2 mA/W at 2 V based voltage, respectively. (semiconductor devices)

An optically controlled SiC lateral power transistor based on SiC/SiCGe super junction structure

Energy Technology Data Exchange (ETDEWEB)

Pu Hongbin; Cao Lin; Ren Jie; Chen Zhiming; Nan Yagong, E-mail: puhongbin@xaut.edu.c [Xi' an University of Technology, Xi' an 710048 (China)

2010-04-15

An optically controlled SiC/SiCGe lateral power transistor based on superjunction structure has been proposed, in which n-SiCGe/p-SiC superjunction structure is employed to improve device figure of merit. Performance of the novel optically controlled power transistor was simulated using Silvaco Atlas tools, which has shown that the device has a very good response to the visible light and the near infrared light. The optoelectronic responsivities of the device at 0.5 {mu}m and 0.7 {mu}m are 330 mA/W and 76.2 mA/W at 2 V based voltage, respectively. (semiconductor devices)

Active structural acoustic control of helicopter interior multifrequency noise using input-output-based hybrid control

Science.gov (United States)

Ma, Xunjun; Lu, Yang; Wang, Fengjiao

2017-09-01

This paper presents the recent advances in reduction of multifrequency noise inside helicopter cabin using an active structural acoustic control system, which is based on active gearbox struts technical approach. To attenuate the multifrequency gearbox vibrations and resulting noise, a new scheme of discrete model predictive sliding mode control has been proposed based on controlled auto-regressive moving average model. Its implementation only needs input/output data, hence a broader frequency range of controlled system is modelled and the burden on the state observer design is released. Furthermore, a new iteration form of the algorithm is designed, improving the developing efficiency and run speed. To verify the algorithm's effectiveness and self-adaptability, experiments of real-time active control are performed on a newly developed helicopter model system. The helicopter model can generate gear meshing vibration/noise similar to a real helicopter with specially designed gearbox and active struts. The algorithm's control abilities are sufficiently checked by single-input single-output and multiple-input multiple-output experiments via different feedback strategies progressively: (1) control gear meshing noise through attenuating vibrations at the key points on the transmission path, (2) directly control the gear meshing noise in the cabin using the actuators. Results confirm that the active control system is practical for cancelling multifrequency helicopter interior noise, which also weakens the frequency-modulation of the tones. For many cases, the attenuations of the measured noise exceed the level of 15 dB, with maximum reduction reaching 31 dB. Also, the control process is demonstrated to be smoother and faster.

India's Proposed Universal Health Coverage Policy: Evidence for Age Structure Transition Effect and Fiscal Sustainability.

Science.gov (United States)

Narayana, Muttur Ranganathan

2016-12-01

India's High Level Expert Group on Universal Health Coverage in 2011 recommended a universal, public-funded and national health coverage policy. As a plausible forward-looking macroeconomic reform in the health sector, this policy proposal on universal health coverage (UHC) needs to be evaluated for age structure transition effect and fiscal sustainability to strengthen its current design and future implementation. Macroeconomic analyses of the long-term implications of age structure transition and fiscal sustainability on India's proposed UHC policy. A new measure of age-specific UHC is developed by combining the age profile of public and private health consumption expenditure by using the National Transfer Accounts methodology. Different projections of age-specific public health expenditure are calculated over the period 2005-2100 to account for the age structure transition effect. The projections include changes in: (1) levels of the expenditure as gross domestic product grows, (2) levels and shape of the expenditure as gross domestic product grows and expenditure converges to that of developed countries (or convergence scenario) based on the Lee-Carter model of forecasting mortality rates, and (3) levels of the expenditure as India moves toward a UHC policy. Fiscal sustainability under each health expenditure projection is determined by using the measures of generational imbalance and sustainability gap in the Generational Accounting methodology. Public health expenditure is marked by age specificities and the elderly population is costlier to support for their healthcare needs in the future. Given the discount and productivity growth rates, the proposed UHC is not fiscally sustainable under India's current fiscal policies except for the convergence scenario. However, if the income elasticity of public expenditure on social welfare and health expenditure is less than one, fiscal sustainability of the UHC policy is attainable in all scenarios of projected public

78 FR 71532 - Amendments to Material Control and Accounting Regulations and Proposed Guidance for Fuel Cycle...

Science.gov (United States)

2013-11-29

... Accounting Regulations and Proposed Guidance for Fuel Cycle Facility Material Control and Accounting Plans... material control and accounting (MC&A) of special nuclear material (SNM) and the proposed guidance... and how the NRC will review and inspect these plans. DATES: The public meeting will be held on...

Protective guide structure for reactor control rod

International Nuclear Information System (INIS)

Ban, Minoru; Umeda, Kenji; Kubo, Noboru; Ito, Tomohiro.

1996-01-01

The present invention provides an improved protective guide structure for control rods, which does not cause swirling of coolants and resonance even though a slit is formed on a protective tube which surrounds a control rod element in a PWR type reactor. Namely, a reactor control rod is constituted with elongated control elements collectively bundled in the form of a cluster. The protective guide structure protectively guides the collected constituent at the upper portion of a reactor container. The protective structure comprises a plurality of protective tubes each having a C-shaped cross section disposed in parallel for receiving control rod elements individually in which the corners of the opening of the cross section of the protective tube are chamfered to an appropriate configuration. With such a constitution, even if coolant flows in a circumferential direction along the protective tubes surrounding the control rod elements, no shearing stream is caused to the coolants flow since the corners of the cross sectional opening (slit) of the tube are chamfered. Accordingly, occurrence of swirlings can be suppressed. (I.S.)

Multiplicity Control in Structural Equation Modeling

Science.gov (United States)

Cribbie, Robert A.

2007-01-01

Researchers conducting structural equation modeling analyses rarely, if ever, control for the inflated probability of Type I errors when evaluating the statistical significance of multiple parameters in a model. In this study, the Type I error control, power and true model rates of famsilywise and false discovery rate controlling procedures were…

Studies and Proposals for an Automatic Crystal Control System

CERN Document Server

Drobychev, Gleb; Khruschinsky, A A; Korzhik, Mikhail; Missevitch, Oleg; Oriboni, André; Peigneux, Jean-Pierre; Schneegans, Marc

1997-01-01

This document presents the status of the studies for an Automatic Crystal Control System ( ACCOS) performed since autumn 1995 for the CMS collaboration. Evaluation of a startstop method for light yield, light uniformity and decay time measurements of PbWO4 crystals is presented, as well as the first results obtained with a compact double-beam spectrophotometer for transverse transmission. Various overall schemes are proposed for an integrated set-up including crystal dimension measurement. The initial financial evaluationperformed is also given.

Proposed quality control protocol of a dual energy bone densitometer from Spanish protocol for quality control of radiology

International Nuclear Information System (INIS)

Saez, F.; Benito, M. A.; Collado, P.; Saez, M.

2011-01-01

In this paper we propose additional testing to complete the tests by the Spanish Protocol for Quality Control of Diagnostic Radiology, taking into account the particular characteristics of these units, and including these tests in the estimation of patient dose dose assessment area. There is also the possibility to independently verify the quality control tests that are done automatically.

Dynamics and control of twisting bi-stable structures

Science.gov (United States)

Arrieta, Andres F.; van Gemmeren, Valentin; Anderson, Aaron J.; Weaver, Paul M.

2018-02-01

Compliance-based morphing structures have the potential to offer large shape adaptation, high stiffness and low weight, while reducing complexity, friction, and scalability problems of mechanism based systems. A promising class of structure that enables these characteristics are multi-stable structures given their ability to exhibit large deflections and rotations without the expensive need for continuous actuation, with the latter only required intermittently. Furthermore, multi-stable structures exhibit inherently fast response due to the snap-through instability governing changes between stable states, enabling rapid configuration switching between the discrete number of programmed shapes of the structure. In this paper, the design and utilisation of the inherent nonlinear dynamics of bi-stable twisting I-beam structures for actuation with low strain piezoelectric materials is presented. The I-beam structure consists of three compliant components assembled into a monolithic single element, free of moving parts, and showing large deflections between two stable states. Finite element analysis is utilised to uncover the distribution of strain across the width of the flange, guiding the choice of positioning for piezoelectric actuators. In addition, the actuation authority is maximised by calculating the generalised coupling coefficient for different positions of the piezoelectric actuators. The results obtained are employed to tailor and test I-beam designs exhibiting desired large deflection between stable states, while still enabling the activation of snap-through with the low strain piezoelectric actuators. To this end, the dynamic response of the I-beams to piezoelectric excitation is investigated, revealing that resonant excitations are insufficient to dynamically trigger snap-through. A novel bang-bang control strategy, which exploits the nonlinear dynamics of the structure successfully triggers both single and constant snap-through between the stable states

Time Delayed Stage-Structured Predator-Prey Model with Birth Pulse and Pest Control Tactics

Directory of Open Access Journals (Sweden)

Mei Yan

2014-01-01

Full Text Available Normally, chemical pesticides kill not only pests but also their natural enemies. In order to better control the pests, two-time delayed stage-structured predator-prey models with birth pulse and pest control tactics are proposed and analyzed by using impulsive differential equations in present work. The stability threshold conditions for the mature prey-eradication periodic solutions of two models are derived, respectively. The effects of key parameters including killing efficiency rate, pulse period, the maximum birth effort per unit of time of natural enemy, and maturation time of prey on the threshold values are discussed in more detail. By comparing the two threshold values of mature prey-extinction, we provide the fact that the second control tactic is more effective than the first control method.

Study on the noncoincidence effect phenomenon using matrix isolated Raman spectra and the proposed structural organization model of acetone in condense phase

Science.gov (United States)

Xu, Wenwen; Wu, Fengqi; Zhao, Yanying; Zhou, Ran; Wang, Huigang; Zheng, Xuming; Ni, Bukuo

2017-03-01

The isotropic and anisotropic Raman spectra of acetone and deuterated acetone isolated in an argon matrix have been recorded for the understanding of noncoincidence effect (NCE) phenomenon. According to the matrix isolated Raman spectra and DFT calculations, we proposed aggregated model for the explanations of the acetone C=O vibration NCE phenomenon and its concentration effect. The experimental data were in consistence with the DFT calculations performed at the B3LYP-D3/6-311 G (d,p) levels based on the proposed model. The experimental identification of the monomer, dimer and trimer are reported here, and the dynamic of the transformation from monomer to aggregated structure can be easily controlled by tuning annealing temperature.

CTAB assisted hydrothermal preparation of YPO4:Tb3+ with controlled morphology, structure and enhanced photoluminescence

International Nuclear Information System (INIS)

Lai, Hua; Du, Ying; Zhao, Min; Sun, Kening; Yang, Lei

2014-01-01

Highlights: • A simple and convenient method toward fabrication of YPO 4 :Tb 3+ with controlled structures and morphologies was proposed. • The crucial role of CTAB during the fabrication process that acts as complexing reagent and inducing agent and the mechanism was discussed. • The addition of CTAB enhances the green emission in YPO 4 :Tb phosphors. -- Abstract: In this paper, we report a simple and convenient method toward fabrication of YPO 4 :Tb 3+ with controlled structures, morphologies and enhanced luminescent properties. By simply controlling the amount of the cetyltrimethyl ammonium bromide (CTAB) during the hydrothermal process, tetragonal YPO 4 :Tb 3+ and hexagonal YPO 4 ·0.8H 2 O:Tb 3+ with nanoparticle and olive-like nanoparticle can be obtained, respectively. Meanwhile, we find that the structures and morphologies can affect their luminescent properties obviously and the intensity of the samples with hexagonal phase is evidently higher than that with tetragonal phase. The variation of crystal structures, morphologies of the samples are ascribed to the crucial role of CTAB during the fabrication process that acts as complexing reagent and inducing agent and the mechanism was also discussed. We believe the method reported here will open a novel approach to rare earth phosphates with multiple structures

Model reduction for the dynamics and control of large structural systems via neutral network processing direct numerical optimization

Science.gov (United States)

Becus, Georges A.; Chan, Alistair K.

1993-01-01

Three neural network processing approaches in a direct numerical optimization model reduction scheme are proposed and investigated. Large structural systems, such as large space structures, offer new challenges to both structural dynamicists and control engineers. One such challenge is that of dimensionality. Indeed these distributed parameter systems can be modeled either by infinite dimensional mathematical models (typically partial differential equations) or by high dimensional discrete models (typically finite element models) often exhibiting thousands of vibrational modes usually closely spaced and with little, if any, damping. Clearly, some form of model reduction is in order, especially for the control engineer who can actively control but a few of the modes using system identification based on a limited number of sensors. Inasmuch as the amount of 'control spillover' (in which the control inputs excite the neglected dynamics) and/or 'observation spillover' (where neglected dynamics affect system identification) is to a large extent determined by the choice of particular reduced model (RM), the way in which this model reduction is carried out is often critical.

The relationship between strategic control and conscious structural knowledge in artificial grammar learning.

Science.gov (United States)

Norman, Elisabeth; Scott, Ryan B; Price, Mark C; Dienes, Zoltan

2016-05-01

We address Jacoby's (1991) proposal that strategic control over knowledge requires conscious awareness of that knowledge. In a two-grammar artificial grammar learning experiment all participants were trained on two grammars, consisting of a regularity in letter sequences, while two other dimensions (colours and fonts) varied randomly. Strategic control was measured as the ability to selectively apply the grammars during classification. For each classification, participants also made a combined judgement of (a) decision strategy and (b) relevant stimulus dimension. Strategic control was found for all types of decision strategy, including trials where participants claimed to lack conscious structural knowledge. However, strong evidence of strategic control only occurred when participants knew or guessed that the letter dimension was relevant, suggesting that strategic control might be associated with - or even causally requires - global awareness of the nature of the rules even though it does not require detailed knowledge of their content. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Servo-controlling structure of five-axis CNC system for real-time NURBS interpolating

Science.gov (United States)

Chen, Liangji; Guo, Guangsong; Li, Huiying

2017-07-01

NURBS (Non-Uniform Rational B-Spline) is widely used in CAD/CAM (Computer-Aided Design / Computer-Aided Manufacturing) to represent sculptured curves or surfaces. In this paper, we develop a 5-axis NURBS real-time interpolator and realize it in our developing CNC(Computer Numerical Control) system. At first, we use two NURBS curves to represent tool-tip and tool-axis path respectively. According to feedrate and Taylor series extension, servo-controlling signals of 5 axes are obtained for each interpolating cycle. Then, generation procedure of NC(Numerical Control) code with the presented method is introduced and the method how to integrate the interpolator into our developing CNC system is given. And also, the servo-controlling structure of the CNC system is introduced. Through the illustration, it has been indicated that the proposed method can enhance the machining accuracy and the spline interpolator is feasible for 5-axis CNC system.

A proposed protocol for remote control of automated assessment devices

International Nuclear Information System (INIS)

Kissock, P.S.; Pritchard, D.A.

1996-01-01

Systems and devices that are controlled remotely are becoming more common in security systems in the US Air Force and other government agencies to provide protection of valuable assets. These systems reduce the number of needed personnel while still providing a high level of protection. However, each remotely controlled device usually has its own communication protocol. This limits the ability to change devices without changing the system that provides the communications control to the device. Sandia is pursuing a standard protocol that can be used to communicate with the different devices currently in use, or may be used in the future, in the US Air Force and other government agencies throughout the security community. Devices to be controlled include intelligent pan/tilt mounts, day/night video cameras, thermal imaging cameras, and remote data processors. Important features of this protocol include the ability to send messages of varying length, identify the sender, and more importantly, control remote data processors. This paper describes the proposed public domain protocol, features, and examples of use. The authors hope to elicit comments from security technology developers regarding format and use of remotely controlled automated assessment devices

The structure of PTSD symptoms according to DSM-5 and IDC-11 proposal: A multi-sample analysis.

Science.gov (United States)

Cyniak-Cieciura, M; Staniaszek, K; Popiel, A; Pragłowska, E; Zawadzki, B

2017-07-01

Posttraumatic stress disorder (PTSD) symptoms structure is a subject of ongoing debate since its inclusion in DSM-III classification in 1980. Different research on PTSD symptoms structure proved the better fit of four-factor and five-factor models comparing to the one proposed by DSM-IV. With the publication of DSM-5 classification, which introduced significant changes to PTSD diagnosis, the question arises about the adequacy of the proposed criteria to the real structure of disorder symptoms. Recent analyses suggest that seven-factor hybrid model is the best reflection of symptoms structure proposed to date. At the same time, some researchers and ICD-11 classification postulate a simplification of PTSD diagnosis restricting it to only three core criteria and adding additional diagnostic unit of complex-PTSD. This research aimed at checking symptoms' structure according to well-known and supported four-, five-, six- and seven-factor models based on DSM-5 symptoms and the conceptualization proposed by the ICD-11 as well as examining the relation between PTSD symptoms categories with borderline personality disorder. Four different trauma populations were examined with self-reported Posttraumatic Diagnostic Scale for DSM-5 (PDS-5) measure. The results suggest that six- and seven-factor hybrid model as well as three-factor ICD-11 concept fits the data better than other models. The core PTSD symptoms were less related to borderline personality disorder than other, broader, symptoms categories only in one sample. Combination of ICD-11 simplified PTSD diagnosis with the more complex approach (e.g. basing on a seven-factor model) may be an attractive proposal for both scientists and practitioners, however does not necessarily lower its comorbidity with borderline personality disorder. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Adaptive control of structural balance for complex dynamical networks based on dynamic coupling of nodes

Science.gov (United States)

Gao, Zilin; Wang, Yinhe; Zhang, Lili

2018-02-01

In the existing research results of the complex dynamical networks controlled, the controllers are mainly used to guarantee the synchronization or stabilization of the nodes’ state, and the terms coupled with connection relationships may affect the behaviors of nodes, this obviously ignores the dynamic common behavior of the connection relationships between the nodes. In fact, from the point of view of large-scale system, a complex dynamical network can be regarded to be composed of two time-varying dynamic subsystems, which can be called the nodes subsystem and the connection relationships subsystem, respectively. Similar to the synchronization or stabilization of the nodes subsystem, some characteristic phenomena can be also emerged in the connection relationships subsystem. For example, the structural balance in the social networks and the synaptic facilitation in the biological neural networks. This paper focuses on the structural balance in dynamic complex networks. Generally speaking, the state of the connection relationships subsystem is difficult to be measured accurately in practical applications, and thus it is not easy to implant the controller directly into the connection relationships subsystem. It is noted that the nodes subsystem and the relationships subsystem are mutually coupled, which implies that the state of the connection relationships subsystem can be affected by the controllable state of nodes subsystem. Inspired by this observation, by using the structural balance theory of triad, the controller with the parameter adaptive law is proposed for the nodes subsystem in this paper, which may ensure the connection relationship matrix to approximate a given structural balance matrix in the sense of the uniformly ultimately bounded (UUB). That is, the structural balance may be obtained by employing the controlling state of the nodes subsystem. Finally, the simulations are used to show the validity of the method in this paper.

Controlling Non-Equilibrium Structure Formation on the Nanoscale.

Science.gov (United States)

Buchmann, Benedikt; Hecht, Fabian Manfred; Pernpeintner, Carla; Lohmueller, Theobald; Bausch, Andreas R

2017-12-06

Controlling the structure formation of gold nanoparticle aggregates is a promising approach towards novel applications in many fields, ranging from (bio)sensing to (bio)imaging to medical diagnostics and therapeutics. To steer structure formation, the DNA-DNA interactions of DNA strands that are coated on the surface of the particles have become a valuable tool to achieve precise control over the interparticle potentials. In equilibrium approaches, this technique is commonly used to study particle crystallization and ligand binding. However, regulating the structural growth processes from the nano- to the micro- and mesoscale remains elusive. Here, we show that the non-equilibrium structure formation of gold nanoparticles can be stirred in a binary heterocoagulation process to generate nanoparticle clusters of different sizes. The gold nanoparticles are coated with sticky single stranded DNA and mixed at different stoichiometries and sizes. This not only allows for structural control but also yields access to the optical properties of the nanoparticle suspensions. As a result, we were able to reliably control the kinetic structure formation process to produce cluster sizes between tens of nanometers up to micrometers. Consequently, the intricate optical properties of the gold nanoparticles could be utilized to control the maximum of the nanoparticle suspension extinction spectra between 525 nm and 600 nm. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of a proposal for evaluating hospital infection control programs.

Science.gov (United States)

Silva, Cristiane Pavanello Rodrigues; Lacerda, Rúbia Aparecida

2011-02-01

To validate the construct and discriminant properties of a hospital infection prevention and control program. The program consisted of four indicators: technical-operational structure; operational prevention and control guidelines; epidemiological surveillance system; and prevention and control activities. These indicators, with previously validated content, were applied to 50 healthcare institutions in the city of São Paulo, Southeastern Brazil, in 2009. Descriptive statistics were used to characterize the hospitals and indicator scores, and Cronbach's α coefficient was used to evaluate the internal consistency. The discriminant validity was analyzed by comparing indicator scores between groups of hospitals: with versus without quality certification. The construct validity analysis was based on exploratory factor analysis with a tetrachoric correlation matrix. The indicators for the technical-operational structure and epidemiological surveillance presented almost 100% conformity in the whole sample. The indicators for the operational prevention and control guidelines and the prevention and control activities presented internal consistency ranging from 0.67 to 0.80. The discriminant validity of these indicators indicated higher and statistically significant mean conformity scores among the group of institutions with healthcare certification or accreditation processes. In the construct validation, two dimensions were identified for the operational prevention and control guidelines: recommendations for preventing hospital infection and recommendations for standardizing prophylaxis procedures, with good correlation between the analysis units that formed the guidelines. The same was found for the prevention and control activities: interfaces with treatment units and support units were identified. Validation of the measurement properties of the hospital infection prevention and control program indicators made it possible to develop a tool for evaluating these programs

Automatic micropart assembly of 3-Dimensional structure by vision based control

International Nuclear Information System (INIS)

Wang, Lidai; Kim, Seung Min

2008-01-01

We propose a vision control strategy to perform automatic microassembly tasks in three-dimension (3-D) and develop relevant control software: specifically, using a 6 degree-of-freedom (DOF) robotic workstation to control a passive microgripper to automatically grasp a designated micropart from the chip, pivot the micropart, and then move the micropart to be vertically inserted into a designated slot on the chip. In the proposed control strategy, the whole microassembly task is divided into two subtasks, micro-grasping and micro-joining, in sequence. To guarantee the success of microassembly and manipulation accuracy, two different two-stage feedback motion strategies, the pattern matching and auto-focus method are employed, with the use of vision-based control system and the vision control software developed. Experiments conducted demonstrate the efficiency and validity of the proposed control strategy

Automatic micropart assembly of 3-Dimensional structure by vision based control

Energy Technology Data Exchange (ETDEWEB)

Wang, Lidai [University of Toronto, Toronto (Canada); Kim, Seung Min [Korean Intellectual Property Office, Daejeon (Korea, Republic of)

2008-12-15

We propose a vision control strategy to perform automatic microassembly tasks in three-dimension (3-D) and develop relevant control software: specifically, using a 6 degree-of-freedom (DOF) robotic workstation to control a passive microgripper to automatically grasp a designated micropart from the chip, pivot the micropart, and then move the micropart to be vertically inserted into a designated slot on the chip. In the proposed control strategy, the whole microassembly task is divided into two subtasks, micro-grasping and micro-joining, in sequence. To guarantee the success of microassembly and manipulation accuracy, two different two-stage feedback motion strategies, the pattern matching and auto-focus method are employed, with the use of vision-based control system and the vision control software developed. Experiments conducted demonstrate the efficiency and validity of the proposed control strategy

Bedfordshire County Structure Plan. Proposed alterations -Public participation statement. Policy 97: Nuclear waste

International Nuclear Information System (INIS)

1984-01-01

The document describes steps taken, in accord with the Town and Country Planning Act 1971, by Bedfordshire County Council, submitting proposed Alterations to the County Structure Plan to the Secretary of State for the Environment. When approving the submission the Council decided to add an additional Alteration dealing with nuclear waste: as this had not been the subject of public consultation the Council decided to seek the public's views on the proposal before submitting the Alteration. The arrangements for consultation and a list of persons and organizations consulted are given, together with the arrangements for considering comments. (U.K.)

Proposal and validation of a clinical trunk control test in individuals with spinal cord injury.

Science.gov (United States)

Quinzaños, J; Villa, A R; Flores, A A; Pérez, R

2014-06-01

One of the problems that arise in spinal cord injury (SCI) is alteration in trunk control. Despite the need for standardized scales, these do not exist for evaluating trunk control in SCI. To propose and validate a trunk control test in individuals with SCI. National Institute of Rehabilitation, Mexico. The test was developed and later evaluated for reliability and criteria, content, and construct validity. We carried out 531 tests on 177 patients and found high inter- and intra-rater reliability. In terms of criterion validity, analysis of variance demonstrated a statistically significant difference in the test score of patients with adequate or inadequate trunk control according to the assessment of a group of experts. A receiver operating characteristic curve was plotted for optimizing the instrument's cutoff point, which was determined at 13 points, with a sensitivity of 98% and a specificity of 92.2%. With regard to construct validity, the correlation between the proposed test and the spinal cord independence measure (SCIM) was 0.873 (P=0.001) and that with the evolution time was 0.437 (P=0.001). For testing the hypothesis with qualitative variables, the Kruskal-Wallis test was performed, which resulted in a statistically significant difference between the scores in the proposed scale of each group defined by these variables. It was proven experimentally that the proposed trunk control test is valid and reliable. Furthermore, the test can be used for all patients with SCI despite the type and level of injury.

The Similar Structures and Control Problems of Complex Systems

Institute of Scientific and Technical Information of China (English)

无

2002-01-01

In this paper, the naturally evolving complex systems, such as biotic and social ones, are considered. Focusing on their structures, a feature is noteworthy, i.e., the similarity in structures. The relations between the functions and behaviors of these systems and their similar structures will be studied. Owing to the management of social systems and the course of evolution of biotic systems may be regarded as control processes, the researches will be within the scope of control problems. Moreover, since it is difficult to model for biotic and social systems, it will start with the control problems of complex systems, possessing similar structures, in engineering.The obtained results show that for either linear or nonlinear systems and for a lot of control problemssimilar structures lead to a series of simplifications. In general, the original system may be decomposed into reduced amount of subsystems with lower dimensions and simpler structures. By virtue of such subsystems, the control problems of original system can be solved more simply.At last, it turns round to observe the biotic and social systems and some analyses are given.

A Robust Controller Structure for Pico-Satellite Applications

DEFF Research Database (Denmark)

Kragelund, Martin Nygaard; Green, Martin; Kristensen, Mads

This paper describes the development of a robust controller structure for use in pico-satellite missions. The structure relies on unknown disturbance estimation and use of robust control theory to implement a system that is robust to both unmodeled disturbances and parameter uncertainties. As one...

Counter-proposal: A Multi-Agent Negotiation Protocol for Resolving Resource Contention in Open Control Systems

DEFF Research Database (Denmark)

Sørensen, Jan Corfixen; Jørgensen, Bo Nørregaard

2010-01-01

The resource contention problem in control systems based on software agents occurs when agents with different goals compete with each other, to control a shared resource. In this paper we propose the counter-proposal protocol, a negotiation protocol that resolves the resource contention problem...

Integrated structure/control design - Present methodology and future opportunities

Science.gov (United States)

Weisshaar, T. A.; Newsom, J. R.; Zeiler, T. A.; Gilbert, M. G.

1986-01-01

Attention is given to current methodology applied to the integration of the optimal design process for structures and controls. Multilevel linear decomposition techniques proved to be most effective in organizing the computational efforts necessary for ISCD (integrated structures and control design) tasks. With the development of large orbiting space structures and actively controlled, high performance aircraft, there will be more situations in which this concept can be applied.

Performance of diagonal control structures at different operating conditions for polymer electrolyte membrane fuel cells

Energy Technology Data Exchange (ETDEWEB)

Serra, Maria; Husar, Attila; Feroldi, Diego; Riera, Jordi [Institut de Robotica i Informatica Industrial, Universitat Politecnica de Catalunya, Consejo Superior de Investigaciones Cientificas, C. Llorens i Artigas 4, 08028 Barcelona (Spain)

2006-08-25

This work is focused on the selection of operating conditions in polymer electrolyte membrane fuel cells. It analyses efficiency and controllability aspects, which change from one operating point to another. Specifically, several operating points that deliver the same amount of net power are compared, and the comparison is done at different net power levels. The study is based on a complex non-linear model, which has been linearised at the selected operating points. Different linear analysis tools are applied to the linear models and results show important controllability differences between operating points. The performance of diagonal control structures with PI controllers at different operating points is also studied. A method for the tuning of the controllers is proposed and applied. The behaviour of the controlled system is simulated with the non-linear model. Conclusions indicate a possible trade-off between controllability and optimisation of hydrogen consumption. (author)

75 FR 7627 - Notice of Lodging of Proposed Consent Decree Under the Federal Water Pollution Control Act

Science.gov (United States)

2010-02-22

.... (``Defendants'') under the pre-treatment requirements of the Federal Water Pollution Control Act (Clean Water... DEPARTMENT OF JUSTICE Notice of Lodging of Proposed Consent Decree Under the Federal Water Pollution Control Act Notice is hereby given that on February 16, 2010, a proposed Consent Decree was filed...

Theoretical and experimental study on active sound transmission control based on single structural mode actuation using point force actuators.

Science.gov (United States)

Sanada, Akira; Tanaka, Nobuo

2012-08-01

This study deals with the feedforward active control of sound transmission through a simply supported rectangular panel using vibration actuators. The control effect largely depends on the excitation method, including the number and locations of actuators. In order to obtain a large control effect at low frequencies over a wide frequency, an active transmission control method based on single structural mode actuation is proposed. Then, with the goal of examining the feasibility of the proposed method, the (1, 3) mode is selected as the target mode and a modal actuation method in combination with six point force actuators is considered. Assuming that a single input single output feedforward control is used, sound transmission in the case minimizing the transmitted sound power is calculated for some actuation methods. Simulation results showed that the (1, 3) modal actuation is globally effective at reducing the sound transmission by more than 10 dB in the low-frequency range for both normal and oblique incidences. Finally, experimental results also showed that a large reduction could be achieved in the low-frequency range, which proves the validity and feasibility of the proposed method.

Organization of Control Units with Operational Addressing

OpenAIRE

Alexander A. Barkalov; Roman M. Babakov; Larysa A. Titarenko

2012-01-01

The using of operational addressing unit as the block of control unit is proposed. The new structure model of Moore finite-state machine with reduced hardware amount is developed. The generalized structure of operational addressing unit is suggested. An example of synthesis process for Moore finite-state machine with operational addressing unit is given. The analytical researches of proposed structure of control unit are executed.

Is it all about the self? The effect of self-control depletion on ultimatum game proposers

Science.gov (United States)

Halali, Eliran; Bereby-Meyer, Yoella; Ockenfels, Axel

2013-01-01

In the ultimatum-game, as in many real-life social exchange situations, the selfish motive to maximize own gains conflicts with fairness preferences. In the present study we manipulated the availability of cognitive-control resources for ultimatum-game proposers to test whether preference for fairness is a deliberative cognitive-controlled act or an automatic act. In two experiments we found that a shortage of cognitive control (ego depletion) led proposers in the ultimatum game (UG) to propose significantly more equal split offers than non-depleted proposers. These results can be interpreted as resulting from an automatic concern for fairness, or from a greater fear of rejection, which would be in line with a purely self-interested response. To separate these competing explanations, in Experiment 2 we conducted a dictator-game in which the responder cannot reject the offer. In contrast to the increased fairness behavior demonstrated by depleted ultimatum-game proposers, we found that depleted dictator-game allocators chose the equal split significantly less often than non-depleted allocators. These results indicate that fairness preferences are automatically driven among UG proposers. The automatic fair behavior, however, at least partially reflects concern about self-interest gain. We discuss different explanations for these results. PMID:23781182

Variable flushing mechanisms and landscape structure control stream DOC export during snowmelt in a set of nested catchments

Science.gov (United States)

Vincent J. Pacific; Kelsey G. Jencso; Brian L. McGlynn

2010-01-01

Stream DOC dynamics during snowmelt have been the focus of much research, and numerous DOC mobilization and delivery mechanisms from riparian and upland areas have been proposed. However, landscape structure controls on DOC export from riparian and upland landscape elements remains poorly understood. We investigated stream and groundwater DOC dynamics across three...

Optimal Design of Complex Passive-Damping Systems for Vibration Control of Large Structures: An Energy-to-Peak Approach

Directory of Open Access Journals (Sweden)

Francisco Palacios-Quiñonero

2014-01-01

Full Text Available We present a new design strategy that makes it possible to synthesize decentralized output-feedback controllers by solving two successive optimization problems with linear matrix inequality (LMI constraints. In the initial LMI optimization problem, two auxiliary elements are computed: a standard state-feedback controller, which can be taken as a reference in the performance assessment, and a matrix that facilitates a proper definition of the main LMI optimization problem. Next, by solving the second optimization problem, the output-feedback controller is obtained. The proposed strategy extends recent results in static output-feedback control and can be applied to design complex passive-damping systems for vibrational control of large structures. More precisely, by taking advantages of the existing link between fully decentralized velocity-feedback controllers and passive linear dampers, advanced active feedback control strategies can be used to design complex passive-damping systems, which combine the simplicity and robustness of passive control systems with the efficiency of active feedback control. To demonstrate the effectiveness of the proposed approach, a passive-damping system for the seismic protection of a five-story building is designed with excellent results.

A decentralized control method for direct smart grid control of refrigeration systems

DEFF Research Database (Denmark)

Shafiei, Seyed Ehsan; Izadi-Zamanabadi, Roozbeh; Rasmussen, Henrik

2013-01-01

. No model information is required in this method. The temperature limits/constraints are respected. A novel adaptive saturation filter is also proposed to increase the system flexibility in storing and delivering the energy. The proposed control strategy is applied to a simulation benchmark that fairly......A decentralized control method is proposed to govern the electrical power consumption of supermarket refrigeration systems (SRS) for demand-side management in the smart grid. The control structure is designed in a supervisory level to provide desired set-points for distributed level controllers...

Simple control law structure for the control of airplanes by means of their engines

OpenAIRE

Fezans, Nicolas

2011-01-01

In this paper a simple control law structure is presented for the control of airplanes using only the engines' thrust. For the design of such a propulsion controlled aircraft control law, the approach followed in this work is to look for the right level of performance in order to avoid both excessive engines activity and reduction of robustness properties. Another goal is to keep the control law and its tuning as simple as possible: for this a control law structure whose terms can easily be i...

Proposal of inspection methodology for environment radiological control; Proposta de metodologia de inspecao para controle radiologico ambiental

Energy Technology Data Exchange (ETDEWEB)

Martins, Nadia Soido Falcao

2005-07-01

The Radiation Protection and Dosimetry Institute (IRD) of the Brazilian Nuclear Energy Commission (CNEN) is in charge of verifying that the self-monitoring operator is effective to control the radiological quality of environmental around the nuclear facilities and carried out in accordance with the regulatory requirements. While a long time, the verification of compliance was kept by the conduction of large scale monitoring programs around all the authorized installations. The IRD decided to reformulate its performance behavior, starting another kind of control program, due to the number increase of nuclear installations and the diversity of activities conducted by the operators. This program, so-called Monitoring Control Program (PCM) is a regulatory activity developed by the Environmental Impact Assessment Service (SEAIA) of IRD and has the aim of check the effectiveness of authorized self-control. Actually the regulatory control of environmental radiological integrity around the authorized nuclear installation essentially depends on the effectiveness of regulatory inspections fulfilled by the SEAIA/IRD. Due to the implementation of modern practices of management in the IRD, specially the quality management system on regulatory inspection activities, emerged the need of unify these actions. It was also necessary to establish standard procedures required for inspection conduction. This work proposes one methodology for the inspections of environmental radiological control suitable to assure the compliance and effectiveness of environmental and effluent monitoring programs conducted by the operator, through the systematic verification of compliance and data quality assessment. The proposed methodology seeks to attend the appeals for high control standards of environment protection and public health. Here, we presented as products of this work: The inspection handbook and checklists for inspections; one framework for sampling, handling, recording and reporting of

Control and large deformations of marginal disordered structures

Science.gov (United States)

Murugan, Arvind; Pinson, Matthew; Chen, Elizabeth

Designed deformations, such as origami patterns, provide a way to make easily controlled mechanical metamaterials with tailored responses to external forces. We focus on an often overlooked regime of origami - non-linear deformations of large disordered origami patterns with no symmetries. We find that practical questions of control in origami have counterintuitive answers, because of intimate connections to spin glasses and neural networks. For example, 1 degree of freedom origami structures are actually difficult to control about the flat state with a single actuator; the actuator is thrown off by an exponential number of `red herring' zero modes for small deformations, all but one of which disappear at larger deformations. Conversely, structures with multiple programmed motions are much easier to control than expected - in fact, they are as easy to control as a dedicated single-motion structure if the number of programmed motions is below a threshold (`memory capacity').

Secondary Control for Voltage Quality Enhancement in Microgrids

DEFF Research Database (Denmark)

Savaghebi, Mehdi; Jalilian, Alireza; Vasquez, Juan Carlos

2012-01-01

In this paper, a hierarchical control scheme is proposed for enhancement of sensitive load bus (SLB) voltage quality in microgrids. The control structure consists of primary and secondary levels. The primary control level comprises distributed generators (DGs) local controllers. Each of these con......In this paper, a hierarchical control scheme is proposed for enhancement of sensitive load bus (SLB) voltage quality in microgrids. The control structure consists of primary and secondary levels. The primary control level comprises distributed generators (DGs) local controllers. Each...

Proposed changes to the nomenclature of Ichthyophonus sp. life stages and structures.

Science.gov (United States)

Kocan, R M

2013-10-01

Much of the terminology describing Ichthyophonus sp. life stages and structures can be traced to the mistaken classification of this organism as a fungus. This misidentification led early investigators to use mycological terms for the structures they observed; while some terminology is not so easily explained, it appears to have been co-opted from the fields of botany and bacteriology. The purpose of this exercise is to attempt to standardize the terminology associated with Ichthyophonus and to bring it into agreement with terminology currently used to define similar life stages of other protists. The proposed changes are (1) spore/macrospore/mother spore to "schizont," (2) microspore/endospore to "merozoite," and (3) pseudohyphae to "hyphae" or "germ tube."

Event Structure and Cognitive Control

OpenAIRE

Reimer, Jason F.; Radvansky, Gabriel A.; Lorsbach, Thomas C.; Armendarez, Joseph J.

2015-01-01

Recently, a great deal of research has demonstrated that although everyday experience is continuous in nature, it is parsed into separate events. The aim of the present study was to examine whether event structure can influence the effectiveness of cognitive control. Across five experiments we varied the structure of events within the AX-CPT by shifting the spatial location of cues and probes on a computer screen. When location shifts were present, a pattern of AX-CPT performance consistent w...

Smart Materials in Structural Health Monitoring, Control and Biomechanics

CERN Document Server

Soh, Chee-Kiong; Bhalla, Suresh

2012-01-01

"Smart Materials in Structural Health Monitoring, Control and Biomechanics" presents the latest developments in structural health monitoring, vibration control and biomechanics using smart materials. The book mainly focuses on piezoelectric, fibre optic and ionic polymer metal composite materials. It introduces concepts from the very basics and leads to advanced modelling (analytical/ numerical), practical aspects (including software/ hardware issues) and case studies spanning civil, mechanical and aerospace structures, including bridges, rocks and underground structures. This book is intended for practicing engineers, researchers from academic and R&D institutions and postgraduate students in the fields of smart materials and structures, structural health monitoring, vibration control and biomedical engineering. Professor Chee-Kiong Soh and Associate Professor Yaowen Yang both work at the School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. Dr. Suresh Bhalla is an A...

Maintenance of medical nuclear equipment. A proposal for quality control in radiotherapy

International Nuclear Information System (INIS)

Becker, Paulo H.B.

1996-01-01

A project of quality control in radiotherapy that is been implemented by Instituto de Radioprotecao e Dosimetria from Brazilian National Energy Commission (CNEN) in cooperation with International Atomic Energy Agency is described. The establishment of a laboratory for the maintenance of medical dosemeters is proposed

Flow control in s-shaped air intake diffuser of gas turbine using proposed energy promoters

Directory of Open Access Journals (Sweden)

Jessam Raed A.

2017-01-01

Full Text Available This paper presents an experimental and numerical investigation of the flow control in an air intake S-shaped diffuser with and without energy promoters. The S-shaped diffuser had an area ratio 3.1and turning angle of 45°/45°. The proposed energy promoter was named as stream line sheet energy promoter. Computational Fluid Dynamics simulation was performed through commercial ANSYS-FLUENT 16.2 software. The measurements were made inside annular subsection, 45° from 360° of the complete annular shape of the diffuser, at Reynolds number 5.8×104 and turbulence intensity 4.1%. Results for the bare S-shaped diffuser (without energy promoters showed the flow structures within the S-shaped diffuser were dominated by counter-rotating vortices and boundary layer separation especially in the outer surface. The combination of the adverse pressure gradient at the first bend of outer surface and upstream low momentum wakes caused the boundary layer to separate early. The combinations of proposed energy promoters were installed on the inner and outer surfaces at three installation planes. The use of energy promoters resulting in significantly decreased the outer surface boundary layer separation with consequential improving the static pressure coefficient and reduction of total pressure losses

Control of large flexible space structures

Science.gov (United States)

Vandervelde, W. E.

1986-01-01

Progress in robust design of generalized parity relations, design of failure sensitive observers using the geometric system theory of Wonham, computational techniques for evaluation of the performance of control systems with fault tolerance and redundancy management features, and the design and evaluation od control systems for structures having nonlinear joints are described.

Semi Active Control of Civil Structures, Analytical and Numerical Studies

Science.gov (United States)

Kerboua, M.; Benguediab, M.; Megnounif, A.; Benrahou, K. H.; Kaoulala, F.

Structural control for civil structures was born out of a need to provide safer and more efficient designs with the reality of limited resources. The purpose of structural control is to absorb and to reflect the energy introduced by dynamic loads such as winds, waves, earthquakes, and traffic. Today, the protection of civil structures from severe dynamic loading is typically achieved by allowing the structures to be damaged. Semi-active control devices, also called "smart" control devices, assume the positive aspects of both the passive and active control devices. A semi-active control strategy is similar to the active control strategy. Only here, the control actuator does not directly apply force to the structure, but instead it is used to control the properties of a passive energy device, a controllable passive damper. Semi-active control strategies can be used in many of the same civil applications as passive and active control. One method of operating smart cable dampers is in a purely passive capacity, supplying the dampers with constant optimal voltage. The advantages to this strategy are the relative simplicity of implementing the control strategy as compared to a smart or active control strategy and that the dampers are more easily optimally tuned in- place, eliminating the need to have passive dampers with unique optimal damping coefficients. This research investigated semi-active control of civil structures for natural hazard mitigation. The research has two components, the seismic protection of buildings and the mitigation of wind-induced vibration in structures. An ideal semi-active motion equation of a composite beam that consists of a cantilever beam bonded with a PZT patch using Hamilton's principle and Galerkin's method was treated. A series R-L and a parallel R-L shunt circuits are coupled into the motion equation respectively by means of the constitutive relation of piezoelectric material and Kirchhoff's law to control the beam vibration. A

Variable Structure PID Control to Prevent Integrator Windup

Science.gov (United States)

Hall, C. E.; Hodel, A. S.; Hung, J. Y.

1999-01-01

PID controllers are frequently used to control systems requiring zero steady-state error while maintaining requirements for settling time and robustness (gain/phase margins). PID controllers suffer significant loss of performance due to short-term integrator wind-up when used in systems with actuator saturation. We examine several existing and proposed methods for the prevention of integrator wind-up in both continuous and discrete time implementations.

Structure identification of an uncertain network coupled with complex-variable chaotic systems via adaptive impulsive control

International Nuclear Information System (INIS)

Liu Dan-Feng; Wu Zhao-Yan; Ye Qing-Ling

2014-01-01

In this paper, structure identification of an uncertain network coupled with complex-variable chaotic systems is investigated. Both the topological structure and the system parameters can be unknown and need to be identified. Based on impulsive stability theory and the Lyapunov function method, an impulsive control scheme combined with an adaptive strategy is adopted to design effective and universal network estimators. The restriction on the impulsive interval is relaxed by adopting an adaptive strategy. Further, the proposed method can monitor the online switching topology effectively. Several numerical simulations are provided to illustrate the effectiveness of the theoretical results. (general)

Sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage.

Science.gov (United States)

Weng, Falu; Liu, Mingxin; Mao, Weijie; Ding, Yuanchun; Liu, Feifei

2018-05-10

The problem of sampled-data-based vibration control for structural systems with finite-time state constraint and sensor outage is investigated in this paper. The objective of designing controllers is to guarantee the stability and anti-disturbance performance of the closed-loop systems while some sensor outages happen. Firstly, based on matrix transformation, the state-space model of structural systems with sensor outages and uncertainties appearing in the mass, damping and stiffness matrices is established. Secondly, by considering most of those earthquakes or strong winds happen in a very short time, and it is often the peak values make the structures damaged, the finite-time stability analysis method is introduced to constrain the state responses in a given time interval, and the H-infinity stability is adopted in the controller design to make sure that the closed-loop system has a prescribed level of disturbance attenuation performance during the whole control process. Furthermore, all stabilization conditions are expressed in the forms of linear matrix inequalities (LMIs), whose feasibility can be easily checked by using the LMI Toolbox. Finally, numerical examples are given to demonstrate the effectiveness of the proposed theorems. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Proposing a clinical quantification framework of macro-linguistic structures in aphasic narratives

Directory of Open Access Journals (Sweden)

Anthony Pak Hin Kong

2014-03-01

Full Text Available Background Analysis of aphasic narratives can be a challenge for clinicians. Previous studies have mainly employed measures that categorized speech samples at the word level. They included quantification of the use and misuse of different word classes, presence and absence of narrative contents and errors, paraphasias, and perseverations, as well as morphological structures and errors within a narrative. In other words, a great amount of research has been conducted in the aphasiology literature focusing on micro-linguistic structures of oral narratives. Aspects of macro- linguistic structures, such as the analysis of content information by a speaker, consistency of using cohesive devices to present information within a narrative, and order of presenting information necessary to form a coherent discourse, have not been extensively investigated. The current investigation proposes a clinical analytic system to target three aspects of macro-linguistic structures in narratives among speakers with aphasia. Specifically, (1 the presence of search events (i.e., the mentioning of key events that allow the listener to understand; Capilouto, Wright, &Wagovich, 2006 within a narrative, (2 the sequence of the mentioned events, and (3 the informativeness (i.e., the fulfillment of lexical items that allow the user to understand what the event is detailing of the event contents, were focused in the proposed framework. Method Ten controls transcripts from were selected from the AphasiaBank (MacWhinney, Fromm, Forbes, & Holland, 2011. Three narrative tasks, including sequential picture description of ‘Refused Umbrella’, procedural narrative of making a ‘Peanut Butter and Jelly Sandwich’, and telling of ‘Cinderella’ story, were used to establish normative data for the basis of analysis. Specifically, the Search Events (e and Informative Words (i used by at least 70% of the speakers were listed for each genre. The sequential order of mentioning the

Compact Radiative Control Structures for Millimeter Astronomy

Science.gov (United States)

Brown, Ari D.; Chuss, David T.; Chervenak, James A.; Henry, Ross M.; Moseley, s. Harvey; Wollack, Edward J.

2010-01-01

We have designed, fabricated, and tested compact radiative control structures, including antireflection coatings and resonant absorbers, for millimeter through submillimeter wave astronomy. The antireflection coatings consist of micromachined single crystal silicon dielectric sub-wavelength honeycombs. The effective dielectric constant of the structures is set by the honeycomb cell geometry. The resonant absorbers consist of pieces of solid single crystal silicon substrate and thin phosphorus implanted regions whose sheet resistance is tailored to maximize absorption by the structure. We present an implantation model that can be used to predict the ion energy and dose required for obtaining a target implant layer sheet resistance. A neutral density filter, a hybrid of a silicon dielectric honeycomb with an implanted region, has also been fabricated with this basic approach. These radiative control structures are scalable and compatible for use large focal plane detector arrays.

Seismic active control by a heuristic-based algorithm

International Nuclear Information System (INIS)

Tang, Yu.

1996-01-01

A heuristic-based algorithm for seismic active control is generalized to permit consideration of the effects of control-structure interaction and actuator dynamics. Control force is computed at onetime step ahead before being applied to the structure. Therefore, the proposed control algorithm is free from the problem of time delay. A numerical example is presented to show the effectiveness of the proposed control algorithm. Also, two indices are introduced in the paper to assess the effectiveness and efficiency of control laws

A novel four-bar linkage prosthetic knee based on magnetorheological effect: principle, structure, simulation and control

Science.gov (United States)

Xu, Lei; Wang, Dai-Hua; Fu, Qiang; Yuan, Gang; Hu, Lei-Zi

2016-11-01

In this paper, the principle and structure of the four-bar linkage prosthetic knee based on the magnetorheological effect (FLPKME) are proposed and realized by individually integrating the upper and lower link rods of the four-bar linkage with the piston rod and the outer cylinder of the magnetorheological (MR) damper. The integrated MR damper, in which the MR fluid is operated in the shear mode, has a double-ended structure. The prototype of the FLPKME is designed and fabricated. Utilizing the developed FLPKME, the lower limb prosthesis is developed, modeled, and simulated. On these bases, the control algorithm for the FLPKME is developed. A test platform for the FLPKME is developed and the performance of the FLPKME with seven constant currents and controlled currents by the control algorithm developed in this paper are experimentally tested. The results show that the FLPKME with a constant current of 1.6 A possesses the basic stable gait, and the FLPKME with the controlled currents by the control algorithm developed in this paper is able to track the motions well and to imitate the natural motions of a healthy human knee joint.

Transverse zones controlling the structural evolution of the Zipaquira Anticline (Eastern Cordillera, Colombia): Regional implications

Science.gov (United States)

García, Helbert; Jiménez, Giovanny

2016-08-01

We report paleomagnetic, magnetic fabric and structural results from 21 sites collected in Cretaceous marine mudstones and Paleogene continental sandstones from the limbs, hinge and transverse zones of the Zipaquira Anticline (ZA). The ZA is an asymmetrical fold with one limb completely overturned by processes like gravity and salt tectonics, and marked by several axis curvatures. The ZA is controlled by at least two (2) transverse zones known as the Neusa and Zipaquira Transverse Zones (NTZ and ZTZ, respectively). Magnetic mineralogy methods were applied at different sites and the main carriers of the magnetic properties are paramagnetic components with some sites being controlled by hematite and magnetite. Magnetic fabric analysis shows rigid-body rotation for the back-limb in the ZA, while the forelimb is subjected to internal deformation. Structural and paleomagnetic data shows the influence of the NTZ and ZTZ in the evolution of the different structures like the ZA and the Zipaquira, Carupa, Rio Guandoque, Las Margaritas and Neusa faults, controlling several factors as vergence, extension, fold axis curvature and stratigraphic detatchment. Clockwise rotations unraveled a block segmentation following a discontinuos model caused by transverse zones and one site reported a counter clockwise rotation associated with a left-lateral strike slip component for transverse faults (e.g. the Neusa Fault). We propose that diverse transverse zones have been active since Paleogene times, playing an important role in the tectonic evolution of the Cundinamarca sub-basin and controlling the structural evolution of folds and faults with block segmentation and rotations.

Analysis of the new architecture proposal for the CMM control system

International Nuclear Information System (INIS)

Heikkilae, L.; Saarinen, H.; Aha, L.; Viinikainen, M.; Mattila, J.; Hahto, A.; Siuko, M.; Semeraro, L.

2011-01-01

While developing divertor remote handling maintenance systems at the Divertor Test Platform 2 facility, some risks and sensitivity points related to the Cassette Multifunctional Mover control system software were discovered and evaluated. The control system architecture has to simultaneously fulfill the demanding ITER remote handling requirements and to face new requirements being uncovered during the trials. Especially evolving non-functional requirements such as reliability and safety have an effect on the control system architecture as it is getting more mature. An evaluation of the implications from architectural decisions is necessary before implementation efforts, as an architecture left to develop without evaluation may lead to a dead end and therefore soaring development costs. After studying existing architecture analysis methods an analysis method was developed to gain confidence to carry out the proposed changes.

On Control Strategies for Responsive Architectural Structures

DEFF Research Database (Denmark)

Kirkegaard, Poul Henning; Parigi, Dario

2012-01-01

The present paper considers control of responsive architectural structures for improvement of structural performance by recognizing changes in their environments and loads, adapting to meet goals, and using past events to improve future performance or maintain serviceability. The general scope of...

Aesthetics-based classification of geological structures in outcrops for geotourism purposes: a tentative proposal

Science.gov (United States)

Mikhailenko, Anna V.; Nazarenko, Olesya V.; Ruban, Dmitry A.; Zayats, Pavel P.

2017-03-01

The current growth in geotourism requires an urgent development of classifications of geological features on the basis of criteria that are relevant to tourist perceptions. It appears that structure-related patterns are especially attractive for geotourists. Consideration of the main criteria by which tourists judge beauty and observations made in the geodiversity hotspot of the Western Caucasus allow us to propose a tentative aesthetics-based classification of geological structures in outcrops, with two classes and four subclasses. It is possible to distinguish between regular and quasi-regular patterns (i.e., striped and lined and contorted patterns) and irregular and complex patterns (paysage and sculptured patterns). Typical examples of each case are found both in the study area and on a global scale. The application of the proposed classification permits to emphasise features of interest to a broad range of tourists. Aesthetics-based (i.e., non-geological) classifications are necessary to take into account visions and attitudes of visitors.

Control range: a controllability-based index for node significance in directed networks

International Nuclear Information System (INIS)

Wang, Bingbo; Gao, Lin; Gao, Yong

2012-01-01

While a large number of methods for module detection have been developed for undirected networks, it is difficult to adapt them to handle directed networks due to the lack of consensus criteria for measuring the node significance in a directed network. In this paper, we propose a novel structural index, the control range, motivated by recent studies on the structural controllability of large-scale directed networks. The control range of a node quantifies the size of the subnetwork that the node can effectively control. A related index, called the control range similarity, is also introduced to measure the structural similarity between two nodes. When applying the index of control range to several real-world and synthetic directed networks, it is observed that the control range of the nodes is mainly influenced by the network's degree distribution and that nodes with a low degree may have a high control range. We use the index of control range similarity to detect and analyze functional modules in glossary networks and the enzyme-centric network of homo sapiens. Our results, as compared with other approaches to module detection such as modularity optimization algorithm, dynamic algorithm and clique percolation method, indicate that the proposed indices are effective and practical in depicting structural and modular characteristics of sparse directed networks

A novel technique for active vibration control, based on optimal

Indian Academy of Sciences (India)

In the last few decades, researchers have proposed many control techniques to suppress unwanted vibrations in a structure. In this work, a novel and simple technique is proposed for the active vibration control. In this technique, an optimal tracking control is employed to suppress vibrations in a structure by simultaneously ...

Distributed cooperative control of AC microgrids

Science.gov (United States)

Bidram, Ali

In this dissertation, the comprehensive secondary control of electric power microgrids is of concern. Microgrid technical challenges are mainly realized through the hierarchical control structure, including primary, secondary, and tertiary control levels. Primary control level is locally implemented at each distributed generator (DG), while the secondary and tertiary control levels are conventionally implemented through a centralized control structure. The centralized structure requires a central controller which increases the reliability concerns by posing the single point of failure. In this dissertation, the distributed control structure using the distributed cooperative control of multi-agent systems is exploited to increase the secondary control reliability. The secondary control objectives are microgrid voltage and frequency, and distributed generators (DGs) active and reactive powers. Fully distributed control protocols are implemented through distributed communication networks. In the distributed control structure, each DG only requires its own information and the information of its neighbors on the communication network. The distributed structure obviates the requirements for a central controller and complex communication network which, in turn, improves the system reliability. Since the DG dynamics are nonlinear and non-identical, input-output feedback linearization is used to transform the nonlinear dynamics of DGs to linear dynamics. Proposed control frameworks cover the control of microgrids containing inverter-based DGs. Typical microgrid test systems are used to verify the effectiveness of the proposed control protocols.

Voltage and Frequency Control for Future Power Systems: the ELECTRA IRP Proposal

DEFF Research Database (Denmark)

D’hulst, R.; Merino Fernandez, J.; Rikos, E.

2015-01-01

In this paper a high level functional architecture for frequency and voltage control for the future (2030+) power system is presented. The proposal suggests a decomposition of the present organization of power system operation into a ”web of cells”. Each cell in this web is managed by a single...

Cavity Control and Panel Control Strategies in Double-Panel Structures for Transmitted Noise Reduction

NARCIS (Netherlands)

Ho, J.; Kalverboer, J.; Berkhoff, Arthur P.

2012-01-01

Investigation and comparisons of the cavity control and the panel control in a double-panel structure are presented in this paper. The double-panel structure, which comprises two panels with air in the gap, provides the advantages of low sound-transmission at high frequency, low heat-transmission

Comparison of various decentralised structural and cavity feedback control strategies for transmitted noise reduction through a double panel structure

Science.gov (United States)

Ho, Jen-Hsuan; Berkhoff, Arthur

2014-03-01

This paper compares various decentralised control strategies, including structural and acoustic actuator-sensor configuration designs, to reduce noise transmission through a double panel structure. The comparison is based on identical control stability indexes. The double panel structure consists of two panels with air in between and offers the advantages of low sound transmission at high frequencies, low heat transmission, and low weight. The double panel structure is widely used, such as in the aerospace and automotive industries. Nevertheless, the resonance of the cavity and the poor sound transmission loss at low frequencies limit the double panel's noise control performance. Applying active structural acoustic control to the panels or active noise control to the cavity has been discussed in many papers. In this paper, the resonances of the panels and the cavity are considered simultaneously to further reduce the transmitted noise through an existing double panel structure. A structural-acoustic coupled model is developed to investigate and compare various structural control and cavity control methods. Numerical analysis and real-time control results show that structural control should be applied to both panels. Three types of cavity control sources are presented and compared. The results indicate that the largest noise reduction is obtained with cavity control by loudspeakers modified to operate as incident pressure sources.

Real-Time Structural Overload Control via Control Allocation Optimization Project

Data.gov (United States)

National Aeronautics and Space Administration — This control methodology utilizes real-time vehicle structural load and shape measurements to actively respond to and protect against vehicle damage due to...

Regulation of Silk Material Structure by Temperature-Controlled Water Vapor Annealing

Science.gov (United States)

Hu, Xiao; Shmelev, Karen; Sun, Lin; Gil, Eun-Seok; Park, Sang-Hyug; Cebe, Peggy; Kaplan, David L.

2011-01-01

We present a simple and effective method to obtain refined control of the molecular structure of silk biomaterials through physical temperature-controlled water vapor annealing (TCWVA). The silk materials can be prepared with control of crystallinity, from a low content using conditions at 4°C (alpha-helix dominated silk I structure), to highest content of ~60% crystallinity at 100°C (beta-sheet dominated silk II structure). This new physical approach covers the range of structures previously reported to govern crystallization during the fabrication of silk materials, yet offers a simpler, green chemistry, approach with tight control of reproducibility. The transition kinetics, thermal, mechanical, and biodegradation properties of the silk films prepared at different temperatures were investigated and compared by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), uniaxial tensile studies, and enzymatic degradation studies. The results revealed that this new physical processing method accurately controls structure, in turn providing control of mechanical properties, thermal stability, enzyme degradation rate, and human mesenchymal stem cell interactions. The mechanistic basis for the control is through the temperature controlled regulation of water vapor, to control crystallization. Control of silk structure via TCWVA represents a significant improvement in the fabrication of silk-based biomaterials, where control of structure-property relationships is key to regulating material properties. This new approach to control crystallization also provides an entirely new green approach, avoiding common methods which use organic solvents (methanol, ethanol) or organic acids. The method described here for silk proteins would also be universal for many other structural proteins (and likely other biopolymers), where water controls chain interactions related to material properties. PMID:21425769

A Structural Analysis Method Formulation for Fault-tolerant Control System Design

DEFF Research Database (Denmark)

Izadi-Zamanabadi, Roozbeh; Staroswiecki, M

2000-01-01

An analysis of structural model representation has been used to extract available inherent redundant information in the system. The paper presents a refined structured model representation based on bipartite directed graph definition and the necessary condition for sensor fusion based...... on the structural observability is proposed...

Control structure selection for energy integrated distillation column

DEFF Research Database (Denmark)

Hansen, J.E.; Jørgensen, Sten Bay

1998-01-01

This paper treats a case study on control structure selection for an almost binary distillation column. The column is energy integrated with a heat pump in order to transfer heat from the condenser to the reboiler. This integrated plant configuration renders the possible control structures somewhat...... different from what is usual for binary distillation columns. Further the heat pump enables disturbances to propagate faster through the system. The plant has six possible actuators of which three must be used to stabilize the system. Hereby three actuators are left for product purity control. An MILP...

Panel Resonance Control and Cavity Control in Double-Panel Structures for Active Noise Reduction

NARCIS (Netherlands)

Ho, J.; Berkhoff, Arthur P.

2011-01-01

An analytical and experimental investigation of panel resonance control and cavity control in a double-panel structure is presented in this paper. The double-panel structure, which consists of two panels with air in the gap, is widely adopted in many applications such as aerospace due to its low

Nonlinear vibration with control for flexible and adaptive structures

CERN Document Server

Wagg, David

2015-01-01

This book provides a comprehensive discussion of nonlinear multi-modal structural vibration problems, and shows how vibration suppression can be applied to such systems by considering a sample set of relevant control techniques. It covers the basic principles of nonlinear vibrations that occur in flexible and/or adaptive structures, with an emphasis on engineering analysis and relevant control techniques. Understanding nonlinear vibrations is becoming increasingly important in a range of engineering applications, particularly in the design of flexible structures such as aircraft, satellites, bridges, and sports stadia. There is an increasing trend towards lighter structures, with increased slenderness, often made of new composite materials and requiring some form of deployment and/or active vibration control. There are also applications in the areas of robotics, mechatronics, micro electrical mechanical systems, non-destructive testing and related disciplines such as structural health monitoring. Two broader ...

Control of noise and structural vibration a MATLAB-based approach

CERN Document Server

Mao, Qibo

2013-01-01

Control of Noise and Structural Vibration presents a MATLAB®-based approach to solving the problems of undesirable noise generation and transmission by structures and of undesirable vibration within structures in response to environmental or operational forces. The fundamentals of acoustics, vibration and coupling between vibrating structures and the sound fields they generate are introduced including a discussion of the finite element method for vibration analysis. Following this, the treatment of sound and vibration control begins, illustrated by example systems such as beams, plates and double plate structures. Sensor and actuator placement is explained as is the idea of modal sensor–actuators. The design of appropriate feedback systems includes consideration of basic stability criteria and robust active structural acoustic control. Single and multi-mode positive position feedback (PPF) control systems are also described in the context of loudspeaker–duct model with non-collocated loudspeaker–microp...

Cooperation-Controlled Learning for Explicit Class Structure in Self-Organizing Maps

Science.gov (United States)

Kamimura, Ryotaro

2014-01-01

We attempt to demonstrate the effectiveness of multiple points of view toward neural networks. By restricting ourselves to two points of view of a neuron, we propose a new type of information-theoretic method called “cooperation-controlled learning.” In this method, individual and collective neurons are distinguished from one another, and we suppose that the characteristics of individual and collective neurons are different. To implement individual and collective neurons, we prepare two networks, namely, cooperative and uncooperative networks. The roles of these networks and the roles of individual and collective neurons are controlled by the cooperation parameter. As the parameter is increased, the role of cooperative networks becomes more important in learning, and the characteristics of collective neurons become more dominant. On the other hand, when the parameter is small, individual neurons play a more important role. We applied the method to the automobile and housing data from the machine learning database and examined whether explicit class boundaries could be obtained. Experimental results showed that cooperation-controlled learning, in particular taking into account information on input units, could be used to produce clearer class structure than conventional self-organizing maps. PMID:25309950

Cooperation-Controlled Learning for Explicit Class Structure in Self-Organizing Maps

Directory of Open Access Journals (Sweden)

Ryotaro Kamimura

2014-01-01

Full Text Available We attempt to demonstrate the effectiveness of multiple points of view toward neural networks. By restricting ourselves to two points of view of a neuron, we propose a new type of information-theoretic method called “cooperation-controlled learning.” In this method, individual and collective neurons are distinguished from one another, and we suppose that the characteristics of individual and collective neurons are different. To implement individual and collective neurons, we prepare two networks, namely, cooperative and uncooperative networks. The roles of these networks and the roles of individual and collective neurons are controlled by the cooperation parameter. As the parameter is increased, the role of cooperative networks becomes more important in learning, and the characteristics of collective neurons become more dominant. On the other hand, when the parameter is small, individual neurons play a more important role. We applied the method to the automobile and housing data from the machine learning database and examined whether explicit class boundaries could be obtained. Experimental results showed that cooperation-controlled learning, in particular taking into account information on input units, could be used to produce clearer class structure than conventional self-organizing maps.

Designing Structure-Dependent MPC-Based AGC Schemes Considering Network Topology

Directory of Open Access Journals (Sweden)

Young-Sik Jang

2015-04-01

Full Text Available This paper presents the important features of structure-dependent model predictive control (MPC-based approaches for automatic generation control (AGC considering network topology. Since power systems have various generators under different topologies, it is necessary to reflect the characteristics of generators in power networks and the control system structures in order to improve the dynamic performance of AGC. Specifically, considering control system structures is very important because not only can the topological problems be reduced, but also a computing system for AGC in a bulk-power system can be realized. Based on these considerations, we propose new schemes in the proposed controller for minimizing inadvertent line flows and computational burden, which strengthen the advantages of MPC-based approach for AGC. Analysis and simulation results in the IEEE 39-bus model system show different dynamic behaviors among structure-dependent control schemes and possible improvements in computational burden via the proposed control scheme while system operators in each balancing area consider physical load reference ramp constraints among generators.

A modelling and control structure for product quality control in climate-controlled processing of agro-material

NARCIS (Netherlands)

Verdijck, G.J.C.; Straten, van G.

2002-01-01

In this paper a modelling and control structure for product quality control is presented for a class of operations that processes agro-material. This class can be characterised as climate-controlled operations, such as storage, transport and drying. The basic model consists of three parts. These are

A proposal of business processes management (BPM structure and use

Directory of Open Access Journals (Sweden)

Rafael Araujo Kluska

2015-09-01

Full Text Available The organizational processes, also known as business processes, have became a fundamental structure for the management of the modern organizations. Knowing the work flow of the organization is a necessary condition for the development of continuous improvement processes. The benefits and advantages provided by the use of an approach based on BPM (Business Processes Management are evident. The benefits include improvements in efficiency, quality and flexibility, besides other aspects generating sustainable competitive advantages. There is a wide range of studies on BPM, which display several definitions and elements characterizing the various applications. This work aims to propose a conceptual framework for interconnection between BPM elements, thus providing a better understanding of organizational processes and performance in organizational management environment. As a result, a group of BPM elements is identified and classified in: methodologies, techniques and tools which are a part of or can be efficiently connected to BPM conceptual structure. A framework for conceptual interconnection between those elements is also provided. The results of BPM application are not limited to the search for operational efficiency, but might also be considered as an element to support the organizational management.

76 FR 23615 - Notice of Submission of Proposed Information Collection to OMB; Quality Control Requirements for...

Science.gov (United States)

2011-04-27

... Proposed Information Collection to OMB; Quality Control Requirements for Direct Endorsement Lenders AGENCY... proposal. This information is collected from Direct Endorsement lenders in order to meet FHA's quality... Lenders. OMB Approval Number: 2502-Pending. Form Numbers: None. Description of the Need for the...

77 FR 2601 - 30-Day Notice of Proposed Information Collection: DS-4164 OMB Control #1405-XXXX

Science.gov (United States)

2012-01-18

... DEPARTMENT OF STATE [Public Notice 7753] 30-Day Notice of Proposed Information Collection: DS-4164 OMB Control 1405-XXXX ACTION: Notice of request for public comment and submission to OMB of proposed collection of information. SUMMARY: The Department of State has submitted the following information...

Flexible structure control experiments using a real-time workstation for computer-aided control engineering

Science.gov (United States)

Stieber, Michael E.

1989-01-01

A Real-Time Workstation for Computer-Aided Control Engineering has been developed jointly by the Communications Research Centre (CRC) and Ruhr-Universitaet Bochum (RUB), West Germany. The system is presently used for the development and experimental verification of control techniques for large space systems with significant structural flexibility. The Real-Time Workstation essentially is an implementation of RUB's extensive Computer-Aided Control Engineering package KEDDC on an INTEL micro-computer running under the RMS real-time operating system. The portable system supports system identification, analysis, control design and simulation, as well as the immediate implementation and test of control systems. The Real-Time Workstation is currently being used by CRC to study control/structure interaction on a ground-based structure called DAISY, whose design was inspired by a reflector antenna. DAISY emulates the dynamics of a large flexible spacecraft with the following characteristics: rigid body modes, many clustered vibration modes with low frequencies and extremely low damping. The Real-Time Workstation was found to be a very powerful tool for experimental studies, supporting control design and simulation, and conducting and evaluating tests withn one integrated environment.

Structural and process factors affecting the implementation of antimicrobial resistance prevention and control strategies in U.S. hospitals.

Science.gov (United States)

Chou, Ann F; Yano, Elizabeth M; McCoy, Kimberly D; Willis, Deanna R; Doebbeling, Bradley N

2008-01-01

To address increases in the incidence of infection with antimicrobial-resistant pathogens, the National Foundation for Infectious Diseases and Centers for Disease Control and Prevention proposed two sets of strategies to (a) optimize antibiotic use and (b) prevent the spread of antimicrobial resistance and control transmission. However, little is known about the implementation of these strategies. Our objective is to explore organizational structural and process factors that facilitate the implementation of National Foundation for Infectious Diseases/Centers for Disease Control and Prevention strategies in U.S. hospitals. We surveyed 448 infection control professionals from a national sample of hospitals. Clinically anchored in the Donabedian model that defines quality in terms of structural and process factors, with the structural domain further informed by a contingency approach, we modeled the degree to which National Foundation for Infectious Diseases and Centers for Disease Control and Prevention strategies were implemented as a function of formalization and standardization of protocols, centralization of decision-making hierarchy, information technology capabilities, culture, communication mechanisms, and interdepartmental coordination, controlling for hospital characteristics. Formalization, standardization, centralization, institutional culture, provider-management communication, and information technology use were associated with optimal antibiotic use and enhanced implementation of strategies that prevent and control antimicrobial resistance spread (all p prevention and control (p support these organizational processes. These findings suggest concrete strategies for evaluating current capabilities to implement effective practices and foster and sustain a culture of patient safety.

Micro ball lightning and its accelerator proposed to control natural phenomena

International Nuclear Information System (INIS)

Matsumoto, Taka-aki

2002-01-01

Micro Ball Lightning (BL) was recently discovered in laboratory. It was also observed during natural phenomena such as volcanic eruption and earthquake. This paper described a brief review of micro BL observed in laboratory as well as during two natural phenomena. Being based on a hypothesis of that those natural phenomena could have been caused by explosive reactions of micro BL, a potential accelerator of micro BL was proposed to control the natural phenomena. (author)

Wireless sensor networks for active vibration control in automobile structures

International Nuclear Information System (INIS)

Mieyeville, Fabien; Navarro, David; Du, Wan; Ichchou, Mohamed; Scorletti, Gérard

2012-01-01

Wireless sensor networks (WSNs) are nowadays widely used in monitoring and tracking applications. This paper presents the feasibility of using WSNs in active vibration control strategies. The method employed here involves active-structural acoustic control using piezoelectric sensors distributed on a car structure. This system aims at being merged with a WSN whose head node collects data and processes control laws so as to command piezoelectric actuators wisely placed on the structure. We will study the feasibility of implementing WSNs in active vibration control and introduce a complete design methodology to optimize hardware/software and control law synergy in mechatronic systems. A design space exploration will be conducted so as to identify the best WSN platform and the resulting impact on control. (paper)

An Efficient Modal Control Strategy for the Active Vibration Control of a Truss Structure

Directory of Open Access Journals (Sweden)

Ricardo Carvalhal

2007-01-01

Full Text Available In this paper an efficient modal control strategy is described for the active vibration control of a truss structure. In this approach, a feedback force is applied to each mode to be controlled according to a weighting factor that is determined by assessing how much each mode is excited by the primary source. The strategy is effective provided that the primary source is at a fixed position on the structure, and that the source is stationary in the statistical sense. To test the effectiveness of the control strategy it is compared with an alternative, established approach namely, Independent Modal Space Control (IMSC. Numerical simulations show that with the new strategy it is possible to significantly reduce the control effort required, with a minimal reduction in control performance.

Vibration control of a flexible structure with electromagnetic actuators

DEFF Research Database (Denmark)

Gruzman, Maurício; Santos, Ilmar

2016-01-01

This work presents the model of a shear-frame-type structure composed of six flexible beams and three rigid masses. Fixed on the ground, outside the structure, two voltage-controlled electromagnetic actuators are used for vibration control. To model the flexible beams, unidimensional finite...... elements were used. Nonlinear equations for the actuator electromagnetic force, noise in the position sensor, time delays for the control signal update and voltage saturation were also considered in the model. For controlling purposes, a discrete linear quadratic regulator combined with a predictive full......-order discrete linear observer was employed. Results of numerical simulations, where the structure is submitted to an impulsive disturbance force and to a harmonic force, show that the oscillations can be significantly reduced with the use of the electromagnetic actuators....

Adaptive Constrained Optimal Control Design for Data-Based Nonlinear Discrete-Time Systems With Critic-Only Structure.

Science.gov (United States)

Luo, Biao; Liu, Derong; Wu, Huai-Ning

2018-06-01

Reinforcement learning has proved to be a powerful tool to solve optimal control problems over the past few years. However, the data-based constrained optimal control problem of nonaffine nonlinear discrete-time systems has rarely been studied yet. To solve this problem, an adaptive optimal control approach is developed by using the value iteration-based Q-learning (VIQL) with the critic-only structure. Most of the existing constrained control methods require the use of a certain performance index and only suit for linear or affine nonlinear systems, which is unreasonable in practice. To overcome this problem, the system transformation is first introduced with the general performance index. Then, the constrained optimal control problem is converted to an unconstrained optimal control problem. By introducing the action-state value function, i.e., Q-function, the VIQL algorithm is proposed to learn the optimal Q-function of the data-based unconstrained optimal control problem. The convergence results of the VIQL algorithm are established with an easy-to-realize initial condition . To implement the VIQL algorithm, the critic-only structure is developed, where only one neural network is required to approximate the Q-function. The converged Q-function obtained from the critic-only VIQL method is employed to design the adaptive constrained optimal controller based on the gradient descent scheme. Finally, the effectiveness of the developed adaptive control method is tested on three examples with computer simulation.

Model Predictive Vibration Control Efficient Constrained MPC Vibration Control for Lightly Damped Mechanical Structures

CERN Document Server

Takács, Gergely

2012-01-01

Real-time model predictive controller (MPC) implementation in active vibration control (AVC) is often rendered difficult by fast sampling speeds and extensive actuator-deformation asymmetry. If the control of lightly damped mechanical structures is assumed, the region of attraction containing the set of allowable initial conditions requires a large prediction horizon, making the already computationally demanding on-line process even more complex. Model Predictive Vibration Control provides insight into the predictive control of lightly damped vibrating structures by exploring computationally efficient algorithms which are capable of low frequency vibration control with guaranteed stability and constraint feasibility. In addition to a theoretical primer on active vibration damping and model predictive control, Model Predictive Vibration Control provides a guide through the necessary steps in understanding the founding ideas of predictive control applied in AVC such as: ·         the implementation of ...

Interval type-2 fuzzy PID controller for uncertain nonlinear inverted pendulum system.

Science.gov (United States)

El-Bardini, Mohammad; El-Nagar, Ahmad M

2014-05-01

In this paper, the interval type-2 fuzzy proportional-integral-derivative controller (IT2F-PID) is proposed for controlling an inverted pendulum on a cart system with an uncertain model. The proposed controller is designed using a new method of type-reduction that we have proposed, which is called the simplified type-reduction method. The proposed IT2F-PID controller is able to handle the effect of structure uncertainties due to the structure of the interval type-2 fuzzy logic system (IT2-FLS). The results of the proposed IT2F-PID controller using a new method of type-reduction are compared with the other proposed IT2F-PID controller using the uncertainty bound method and the type-1 fuzzy PID controller (T1F-PID). The simulation and practical results show that the performance of the proposed controller is significantly improved compared with the T1F-PID controller. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Hierarchical Control Scheme for Voltage Harmonics Compensation in an Islanded Droop-Controlled Microgrid

DEFF Research Database (Denmark)

Savaghebi, Mehdi; Guerrero, Josep M.; Jalilian, Alireza

2011-01-01

In this paper, a microgrid hierarchical control scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controller mainly consists of active and reactive power controllers, voltage and current...... controllers, and virtual impedance loop. A novel virtual impedance structure is proposed to achieve proper sharing of non-fundamental power among the microgrid DGs. The secondary level is designed to manage compensation of voltage harmonics at the microgrid load bus (LB) to which the sensitive loads may...... be connected. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values is directed by the secondary level. These functions are achieved by sending proper control signals to the local controllers. The simulation results show the effectiveness of the proposed control scheme....

Strengthening, modification and repair techniques’ prioritization for structural integrity control of ageing offshore structures

International Nuclear Information System (INIS)

Samarakoon, Samindi M.K.; Ratnayake, R.M. Chandima

2015-01-01

Structural integrity control is vital for existing ageing as well as newly built offshore and onshore structures. Structural integrity control becomes highly sensitive to interventions under a potential loss of structural integrity when it comes to offshore oil and gas production and process facilities. This is mainly due to the inherent constraints present in carrying out engineering work in the offshore atmosphere. It has been further exacerbated by the ageing offshore structures and the necessity of carrying out life extension toward the end of their design service lives. Local and international regulations demand the implementation of appropriate strengthening, modification and repair plans when significant changes in the structural integrity are revealed. In this context, strengthening, modification and repair techniques such as welding, member removal/reduction of loading, mechanical clamping and grouted repairs play a vital role. This manuscript presents an approach for prioritizing the strengthening, modification and repair techniques using a multi-criteria analysis approach. An analytic hierarchy process has been selected for the analysis via an illustrative case. It also provides a comprehensive overview of currently existing; strengthening, modification and repair techniques and their comparative pros and cons. - Highlights: • Structural integrity control (SIC) of ageing and intact offshore structures. • Strengthening, modification and/or repair (SMR) techniques have been explained. • Application of multi-criteria analysis conserving SI has been illustrated. • SMR techniques prioritization and sensitivity analysis has been performed

Structured control for autonomous robots

International Nuclear Information System (INIS)

Simmons, R.G.

1994-01-01

To operate in rich, dynamic environments, autonomous robots must be able to effectively utilize and coordinate their limited physical and occupational resources. As complexity increases, it becomes necessary to impose explicit constraints on the control of planning, perception, and action to ensure that unwanted interactions between behaviors do not occur. This paper advocates developing complex robot systems by layering reactive behaviors onto deliberative components. In this structured control approach, the deliberative components handle normal situations and the reactive behaviors, which are explicitly constrained as to when and how they are activated, handle exceptional situations. The Task Control Architecture (TCA) has been developed to support this approach. TCA provides an integrated set of control constructs useful for implementing deliberative and reactive behaviors. The control constructs facilitate modular and evolutionary system development: they are used to integrate and coordinate planning, perception, and execution, and to incrementally improve the efficiency and robustness of the robot systems. To date, TCA has been used in implementing a half-dozen mobile robot systems, including an autonomous six-legged rover and indoor mobile manipulator

Automatic Control of ITER-like Structures

International Nuclear Information System (INIS)

Bosia, G.; Bremond, S.

2005-01-01

In ITER Ion Cyclotron System requires a power transfer efficiency in excess of 90% from power source to plasma in quasi continuous operation. This implies the availability of a control system capable of optimizing the array radiation spectrum, automatically acquiring impedance match between the power source and the plasma loaded array at the beginning of the power pulse and maintaining it against load variations due to plasma position and plasma edge parameters fluctuations, rapidly detecting voltage breakdowns in the array and/or in the transmission system and reliably discriminating them from fast load variations. In this paper a proposal for a practical ITER control system, including power, phase, frequency and impedance matching is described. (authors)

Structure formation control of foam concrete

Science.gov (United States)

Steshenko, Aleksei; Kudyakov, Aleksander; Konusheva, Viktoriya; Syrkin, Oleg

2017-01-01

The process of predetermined foam concrete structure formation is considered to be a crucial issue from the point of process control and it is currently understudied thus defining the need for additional research. One of the effective ways of structure formation control in naturally hardening foam concrete is reinforcement with dispersed fibers or introduction of plasticizers. The paper aims at studying the patterns of influence of microreinforcing and plasticizing additives on the structure and performance properties of foam concrete. Preparation of foam concrete mix has been conducted using one-step technology. The structure of modified foam concrete has been studied by means of electron microscopy. The cellular structure of foam concrete samples with the additives is homogeneous; the pores are uniformly distributed over the total volume. It has been revealed that introduction of the Neolas 5.2 plasticizer and microreinforcing fibers in the foam concrete mixture in the amount of 0.4 - 0.1 % by weight of cement leads to reduction of the average pore diameter in the range of 45.3 to 30.2 microns and the standard deviation of the pore average diameter from 23.6 to 9.2 in comparison with the sample without additive. Introduction of modifying additives has stimulated formation of a large number of closed pores. Thus porosity of conditionally closed pores has increased from 16.06 % to 34.48 %, which has lead to increase of frost resistance brand of foam concrete from F15 to F50 and to reduction of its water absorption by weight by 20 %.

Design and implementation of multichannel global active structural acoustic control for a device casing

Science.gov (United States)

Mazur, Krzysztof; Wrona, Stanislaw; Pawelczyk, Marek

2018-01-01

The paper presents the idea and discussion on implementation of multichannel global active noise control systems. As a test plant an active casing is used. It has been developed by the authors to reduce device noise directly at the source by controlling vibration of its casing. To provide global acoustic effect in the whole environment, where the device operates, it requires a number of secondary sources and sensors for each casing wall, thus making the whole active control structure complicated, i.e. with a large number of interacting channels. The paper discloses all details concerning hardware setup and efficient implementation of control algorithms for the multichannel case. A new formulation is presented to introduce the distributed version of the Switched-error Filtered-reference Least Mean Squares (FXLMS) algorithm together with adaptation rate enhancement. The convergence rate of the proposed algorithm is compared with original Multiple-error FXLMS. A number of hints followed from many years of authors' experience on microprocessor control systems design and signal processing algorithms optimization are presented. They can be used for various active control and signal processing applications, both for academic research and commercialization.

75 FR 17942 - Notice of Proposed Information Collection for Public Comment on the Quality Control for Rental...

Science.gov (United States)

2010-04-08

... Information Collection for Public Comment on the Quality Control for Rental Assistance Subsidy Determinations... respondent burden (e.g., permitting electronic submission of responses). Title of Proposal: Quality Control... covered by the Public Housing and Section 8 housing subsidies. The Quality Control process involves...

A Novel Secondary Control for Microgrid Based on Synergetic Control of Multi-Agent System

Directory of Open Access Journals (Sweden)

Zhiwen Yu

2016-03-01

Full Text Available In power systems, the secondary control is a very useful way to restore the system frequency and voltage to the rated value. This paper tries to propose a secondary frequency and voltage control of islanded microgrids based on the distributed synergetic control of multi-agent systems. In the proposed control, since each distributed generation only requires its own information and that of the neighbors, the secondary control is fully distributed. The system is more reliable because the central controller and complex communication network are reduced in the distributed structure. Based on multi-agent systems, the dynamic model is established, and distributed synergetic control algorithms are given to design the secondary control of the islanded microgrid. Meanwhile, the system has globally asymptotic stability under the proposed control, which is proved by the direct Lyapunov method. Simulation results about a test microgrid are given to verify the effectiveness of the proposed control.

The qualitative research proposal

Directory of Open Access Journals (Sweden)

H Klopper

2008-09-01

Full Text Available Qualitative research in the health sciences has had to overcome many prejudices and a number of misunderstandings, but today qualitative research is as acceptable as quantitative research designs and is widely funded and published. Writing the proposal of a qualitative study, however, can be a challenging feat, due to the emergent nature of the qualitative research design and the description of the methodology as a process. Even today, many sub-standard proposals at post-graduate evaluation committees and application proposals to be considered for funding are still seen. This problem has led the researcher to develop a framework to guide the qualitative researcher in writing the proposal of a qualitative study based on the following research questions: (i What is the process of writing a qualitative research proposal? and (ii What does the structure and layout of a qualitative proposal look like? The purpose of this article is to discuss the process of writing the qualitative research proposal, as well as describe the structure and layout of a qualitative research proposal. The process of writing a qualitative research proposal is discussed with regards to the most important questions that need to be answered in your research proposal with consideration of the guidelines of being practical, being persuasive, making broader links, aiming for crystal clarity and planning before you write. While the structure of the qualitative research proposal is discussed with regards to the key sections of the proposal, namely the cover page, abstract, introduction, review of the literature, research problem and research questions, research purpose and objectives, research paradigm, research design, research method, ethical considerations, dissemination plan, budget and appendices.

Challenges of Control in Functional Organization Structures: Example of Outsourcing Sector

Directory of Open Access Journals (Sweden)

Agnieszka Maciejczyk

2016-07-01

Full Text Available Effective control of an organization is strictly connected with its organization structure. When a company decides to outsource a part of its operations, a new structure is applied. Also, the system of control should be reviewed and adjusted to the new model of business in order to be effective. Usually, the outsourcing companies apply functional organization structure which is the most common way of grouping business activities. The goal of the paper was to point challenges and aspects which should be taken into consideration in order to adapt control systems to new organization structures in case of Business Process Outsourcing and Shared Service Centers. The research was based on literature studies as well as empirical analysis of selected companies from business service centers sector. The key findings of the study suggest that the mechanisms of control differ in Business Process Outsourcing and Shared Service organizations although both base on building trust and relationship. The main challenges of adapting the control system to new conditions comprise people and process related factors such as: knowledge management, control split and owners, new processes flows, virtual teams. Building control system is a process which foundation is a new organization structure.

Modal estimation by FBG for flexible structures attitude control

NARCIS (Netherlands)

Jiang, Hao; Van Der Veek, B.; Dolk, V.; Kirk, D.; Gutierrez, H.

2014-01-01

This work investigates an online mode shape estimation method to estimate the time-varying modal properties and correct IMU readings in real time using distributed strain measurements of FBG sensor arrays. Compared to the notch filter approach, the proposed method removes structural vibration

Control Structures for Smart Grid Balancing

DEFF Research Database (Denmark)

Juelsgaard, Morten; Totu, Luminita Cristiana; Shafiei, Seyed Ehsan

2013-01-01

This work addresses the problem of maintaining the balance between consumption and production in the electricity grid when volatile resources, such as wind and sun, account for a large percentage of the power generation. We present control structures for Smart Grid balancing services on three...

Performance and robustness of hybrid model predictive control for controllable dampers in building models

Science.gov (United States)

Johnson, Erik A.; Elhaddad, Wael M.; Wojtkiewicz, Steven F.

2016-04-01

A variety of strategies have been developed over the past few decades to determine controllable damping device forces to mitigate the response of structures and mechanical systems to natural hazards and other excitations. These "smart" damping devices produce forces through passive means but have properties that can be controlled in real time, based on sensor measurements of response across the structure, to dramatically reduce structural motion by exploiting more than the local "information" that is available to purely passive devices. A common strategy is to design optimal damping forces using active control approaches and then try to reproduce those forces with the smart damper. However, these design forces, for some structures and performance objectives, may achieve high performance by selectively adding energy, which cannot be replicated by a controllable damping device, causing the smart damper performance to fall far short of what an active system would provide. The authors have recently demonstrated that a model predictive control strategy using hybrid system models, which utilize both continuous and binary states (the latter to capture the switching behavior between dissipative and non-dissipative forces), can provide reductions in structural response on the order of 50% relative to the conventional clipped-optimal design strategy. This paper explores the robustness of this newly proposed control strategy through evaluating controllable damper performance when the structure model differs from the nominal one used to design the damping strategy. Results from the application to a two-degree-of-freedom structure model confirms the robustness of the proposed strategy.

Secondary Control Scheme for Voltage Unbalance Compensation in an Islanded Droop-Controlled Microgrid

DEFF Research Database (Denmark)

Savaghebi, Mehdi; Jalilian, Alireza; Vasquez, Juan Carlos

2012-01-01

The concept of microgrid hierarchical control is presented recently. In this paper, a hierarchical scheme is proposed which includes primary and secondary control levels. The primary level comprises distributed generators (DGs) local controllers. The local controllers mainly consist of power......, voltage and current controllers, and virtual impedance control loop. The central secondary controller is designed to manage the compensation of voltage unbalance at the point of common coupling (PCC) in an islanded microgrid. Unbalance compensation is achieved by sending proper control signals to the DGs...... local controllers. The design procedure of the control system is discussed in detail and the simulation results are presented. The results show the effectiveness of the proposed control structure in compensating the voltage unbalance....

A Generalised Fault Protection Structure Proposed for Uni-grounded Low-Voltage AC Microgrids

Science.gov (United States)

Bui, Duong Minh; Chen, Shi-Lin; Lien, Keng-Yu; Jiang, Jheng-Lun

2016-04-01

This paper presents three main configurations of uni-grounded low-voltage AC microgrids. Transient situations of a uni-grounded low-voltage (LV) AC microgrid (MG) are simulated through various fault tests and operation transition tests between grid-connected and islanded modes. Based on transient simulation results, available fault protection methods are proposed for main and back-up protection of a uni-grounded AC microgrid. In addition, concept of a generalised fault protection structure of uni-grounded LVAC MGs is mentioned in the paper. As a result, main contributions of the paper are: (i) definition of different uni-grounded LVAC MG configurations; (ii) analysing transient responses of a uni-grounded LVAC microgrid through line-to-line faults, line-to-ground faults, three-phase faults and a microgrid operation transition test, (iii) proposing available fault protection methods for uni-grounded microgrids, such as: non-directional or directional overcurrent protection, under/over voltage protection, differential current protection, voltage-restrained overcurrent protection, and other fault protection principles not based on phase currents and voltages (e.g. total harmonic distortion detection of currents and voltages, using sequence components of current and voltage, 3I0 or 3V0 components), and (iv) developing a generalised fault protection structure with six individual protection zones to be suitable for different uni-grounded AC MG configurations.

Transform methods for precision continuum and control models of flexible space structures

Science.gov (United States)

Lupi, Victor D.; Turner, James D.; Chun, Hon M.

1991-01-01

An open loop optimal control algorithm is developed for general flexible structures, based on Laplace transform methods. A distributed parameter model of the structure is first presented, followed by a derivation of the optimal control algorithm. The control inputs are expressed in terms of their Fourier series expansions, so that a numerical solution can be easily obtained. The algorithm deals directly with the transcendental transfer functions from control inputs to outputs of interest, and structural deformation penalties, as well as penalties on control effort, are included in the formulation. The algorithm is applied to several structures of increasing complexity to show its generality.

Electric field control of deterministic current-induced magnetization switching in a hybrid ferromagnetic/ferroelectric structure

Science.gov (United States)

Cai, Kaiming; Yang, Meiyin; Ju, Hailang; Wang, Sumei; Ji, Yang; Li, Baohe; Edmonds, Kevin William; Sheng, Yu; Zhang, Bao; Zhang, Nan; Liu, Shuai; Zheng, Houzhi; Wang, Kaiyou

2017-07-01

All-electrical and programmable manipulations of ferromagnetic bits are highly pursued for the aim of high integration and low energy consumption in modern information technology. Methods based on the spin-orbit torque switching in heavy metal/ferromagnet structures have been proposed with magnetic field, and are heading toward deterministic switching without external magnetic field. Here we demonstrate that an in-plane effective magnetic field can be induced by an electric field without breaking the symmetry of the structure of the thin film, and realize the deterministic magnetization switching in a hybrid ferromagnetic/ferroelectric structure with Pt/Co/Ni/Co/Pt layers on PMN-PT substrate. The effective magnetic field can be reversed by changing the direction of the applied electric field on the PMN-PT substrate, which fully replaces the controllability function of the external magnetic field. The electric field is found to generate an additional spin-orbit torque on the CoNiCo magnets, which is confirmed by macrospin calculations and micromagnetic simulations.

Proposed American National Standard ANS 8.22: Nuclear criticality safety based on limiting and controlling moderators

International Nuclear Information System (INIS)

Bullington, J.S.

1996-01-01

This proposed standard features guidance for dealing with the combination of fissile material and moderators in moderator control areas. The main points include nuclear criticality safety practices, encompassing administrative practices and process evaluations, and engineering practices, encompassing moderator control area barriers, equipment and containers, penetrations, fire prevention and suppression, and active engineered controls. Four appendixes follow the standard; the subject of these appendixes are typical moderating materials, potential sources of moderators, moderator control measurements, and engineered barriers to control moderators

Compilation of floristic and herbarium specimen datain Iran: proposal to data structure

Directory of Open Access Journals (Sweden)

Majid Sharifi-Tehrani

2013-09-01

Full Text Available Floristic databases constitute the second level of plant information systems, after taxonomic-nomenclatural databases. This paper provided the details of data structure and available data resources to develop a floristic database, along with some explanations on taxonomic and floristic databases. Also, this paper proposed the availability and possibility of a shortcut to constructing a national floristic database through uniforming and compilation of dispersed floristic data contained in various botanical centers of Iran. Therefore, Iran could be the second country in SW Asia region to have a national floristic database, and the resulted services can be presented to national scientific community.

Inference Attacks and Control on Database Structures

Directory of Open Access Journals (Sweden)

Muhamed Turkanovic

2015-02-01

Full Text Available Today’s databases store information with sensitivity levels that range from public to highly sensitive, hence ensuring confidentiality can be highly important, but also requires costly control. This paper focuses on the inference problem on different database structures. It presents possible treats on privacy with relation to the inference, and control methods for mitigating these treats. The paper shows that using only access control, without any inference control is inadequate, since these models are unable to protect against indirect data access. Furthermore, it covers new inference problems which rise from the dimensions of new technologies like XML, semantics, etc.

Vibration control in smart coupled beams subjected to pulse excitations

Science.gov (United States)

Pisarski, Dominik; Bajer, Czesław I.; Dyniewicz, Bartłomiej; Bajkowski, Jacek M.

2016-10-01

In this paper, a control method to stabilize the vibration of adjacent structures is presented. The control is realized by changes of the stiffness parameters of the structure's couplers. A pulse excitation applied to the coupled adjacent beams is imposed as the kinematic excitation. For such a representation, the designed control law provides the best rate of energy dissipation. By means of a stability analysis, the performance in different structural settings is studied. The efficiency of the proposed strategy is examined via numerical simulations. In terms of the assumed energy metric, the controlled structure outperforms its passively damped equivalent by over 50 percent. The functionality of the proposed control strategy should attract the attention of practising engineers who seek solutions to upgrade existing damping systems.

Disturbance observer based current controller for vector controlled IM drives

DEFF Research Database (Denmark)

Teodorescu, Remus; Dal, Mehmet

2008-01-01

induction motor (IM) drives. The control design, based on synchronously rotating d-q frame model of the machine, has a simple structure that combines the proportional portion of a conventional PI control and output of the observer. The observer is predicted to estimate the disturbances caused by parameters...... coupling effects and increase robustness against parameters change without requiring any other compensation strategies. The experimental implementation results are provided to demonstrate validity and performance of the proposed control scheme.......In order to increase the accuracy of the current control loop, usually, well known parameter compensation and/or cross decoupling techniques are employed for advanced ac drives. In this paper, instead of using these techniques an observer-based current controller is proposed for vector controlled...

Towards friction control using laser-induced periodic surface structures

NARCIS (Netherlands)

Eichstädt, J.; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert; Schmidt, M.; Zaeh, M.

2011-01-01

This paper aims at contributing to the study of laser-induced periodic surface structures (LIPSS) and the description of their tribological properties in order to facilitate the knowledge for contact mechanical applications. To obtain laser parameters for LIPSS formation, we propose to execute two

78 FR 79328 - Amendments to Material Control and Accounting Regulations and Proposed Guidance for Fuel Cycle...

Science.gov (United States)

2013-12-30

..., 72, 74, and 150 [NRC-2009-0096 and NRC-2013-0195] RIN 3150-AI61 Amendments to Material Control and Accounting Regulations and Proposed Guidance for Fuel Cycle Facility Material Control and Accounting Plans... of this document. NRC's Agencywide Documents Access and Management System (ADAMS): You may access...

Control-structure interaction in precision pointing servo loops

Science.gov (United States)

Spanos, John T.

1989-01-01

The control-structure interaction problem is addressed via stability analysis of a generic linear servo loop model. With the plant described by the rigid body mode and a single elastic mode, structural flexibility is categorized into one of three types: (1) appendage, (2) in-the-loop minimum phase, and (3) in-the-loop nonminimum phase. Closing the loop with proportional-derivative (PD) control action and introducing sensor roll-off dynamics in the feedback path, stability conditions are obtained. Trade studies are conducted with modal frequency, modal participation, modal damping, loop bandwidth, and sensor bandwidth treated as free parameters. Results indicate that appendage modes are most likely to produce instability if they are near the sensor rolloff, whereas in-the-loop modes are most dangerous near the loop bandwidth. The main goal of this paper is to provide a fundamental understanding of the control-structure interaction problem so that it may benefit the design of complex spacecraft and pointing system servo loops. In this framework, the JPL Pathfinder gimbal pointer is considered as an example.

Feedback Linearized Aircraft Control Using Dynamic Cell Structure

Science.gov (United States)

Jorgensen, C. C.

1998-01-01

A Dynamic Cell Structure (DCS ) Neural Network was developed which learns a topology representing network (TRN) of F-15 aircraft aerodynamic stability and control derivatives. The network is combined with a feedback linearized tracking controller to produce a robust control architecture capable of handling multiple accident and off-nominal flight scenarios. This paper describes network and its performance for accident scenarios including differential stabilator lock, soft sensor failure, control, stability derivative variation, and turbulence.

Yaw control for active damping of structural dynamics

Energy Technology Data Exchange (ETDEWEB)

Ekelund, T. [Chalmers Univ. of Technology, Goeteborg (Sweden). Control Engineering Lab.

1996-12-01

Yaw torque control for reduction of structural dynamic loads in a two-bladed wind turbine is investigated. The models are obtained using rigid-body mechanics. Linear quadratic control theory is utilized for design and analysis. The analysis of two simple examples, where the teeter angle and the tower lateral bending motion are regarded, shows that a time-varying controller has some advantages compared with a time-invariant controller. 6 refs, 9 figs

Structural mapping from MSS-LANDSAT imagery: A proposed methodology for international geological correlation studies

Science.gov (United States)

Dejesusparada, N. (Principal Investigator); Crepani, E.; Martini, P. R.

1980-01-01

A methodology is proposed for international geological correlation studies based on LANDSAT-MSS imagery, Bullard's model of continental fit and compatible structural trends between Northeast Brazil and the West African counterpart. Six extensive lineaments in the Brazilian study area are mapped and discussed according to their regional behavior and in relation to the adjacent continental margin. Among the first conclusions, correlations were found between the Sobral Pedro II Lineament and the megafaults that surround the West African craton; and the Pernambuco Lineament with the Ngaurandere Linemanet in Cameroon. Ongoing research to complete the methodological stages includes the mapping of the West African structural framework, reconstruction of the pre-drift puzzle, and an analysis of the counterpart correlations.

Report on planning of input earthquake vibration for design of vibration controlling structure, in the Tokai Works, Power Reactor and Nuclear Fuel Development Corporation

International Nuclear Information System (INIS)

Uryu, Mitsuru; Shinohara, Takaharu; Terada, Shuji; Yamazaki, Toshihiko; Nakayama, Kazuhiko; Kondo, Toshinari; Hosoya, Hisashi

1997-05-01

When adopting a vibration controlling structure for a nuclear facility building, it is necessary to evaluate a little longer frequency vibration properly. Although various evaluation methods are proposed, there is no finished method. And, to the earthquake itself to investigate, some factors such as effect of surface wave, distant great earthquake, and so on must be considered, and further various evaluations and investigations are required. Here is reported on an evaluation method of the input earthquake vibration for vibration controlling design establishing on adoption of the vibration controlling structure using a vibration control device comprising of laminated rubber and lead damper for the buildings of reprocessing facility in Tokai Works. The input earthquake vibration for vibration controlling design shown in this report is to be adopted for a vibration controlling facility buildings in the Tokai Works. (G.K.)

Nonlinear model-based robust control of a nuclear reactor using adaptive PIF gains and variable structure controller

International Nuclear Information System (INIS)

Park, Moon Ghu; Cho, Nam Zin

1993-01-01

A Nonlinear model-based Hybrid Controller (NHC) is developed which consists of the adaptive proportional-integral-feedforward (PIF) gains and variable structure controller. The controller has the robustness against modeling uncertainty and is applied to the trajectory tracking control of single-input, single-output nonlinear systems. The essence of the scheme is to divide the control into four different terms. Namely, the adaptive P-I-F gains and variable structure controller are used to accomplish the specific control actions by each terms. The robustness of the controller is guaranteed by the feedback of estimated uncertainty and the performance specification given by the adaptation of PIF gains using the second method of Lyapunov. The variable structure controller is incorporated to regulate the initial peak of the tracking error during the parameter adaptation is not settled yet. The newly developed NHC method is applied to the power tracking control of a nuclear reactor and the simulation results show great improvement in tracking performance compared with the conventional model-based control methods. (Author)

Application of betatrons to quality control of structures

International Nuclear Information System (INIS)

Klevtsov, V.A.; Matveev, Yu.K.; Trefilov, V.V.

1986-01-01

The results of laboratory investigations on the applicability of modificated PMB-6 betatron to quality control of reinforced concrete structures are presented. The investigations have been performed for the purposes of refinement of the technique for detecting voids and establishing real reinforcement. On the basis of experimental investigations the technique and schemes of structure translucence have been developed. Examples of using betatrons for flaw detection of reinforred concrete structures are given

Genetic Algorithm Tuning of PID Controller in Smith Predictor for Glucose Concentration Control

OpenAIRE

Tsonyo Slavov; Olympia Roeva

2011-01-01

This paper focuses on design of a glucose concentration control system based on nonlinear model plant of E. coli MC4110 fed-batch cultivation process. Due to significant time delay in real time glucose concentration measurement, a correction is proposed in glucose concentration measurement and a Smith predictor (SP) control structure based on universal PID controller is designed. To reduce the influence of model error in SP structure the estimate of measured glucose concentration is used. For...

Proposal of an Institutional Structure for the Cooperative Sector in Cuba

Directory of Open Access Journals (Sweden)

Iriadna Marín de León

2013-12-01

Full Text Available In the Economic and Social Politics Guidelines of the CCP Congress, devoted to cooperative economic administration defined five specific guidelines that denote the intention and purpose of the country for recognizing the role of the cooperative as in the development way in the social Cuban socialist model and the necessity to extend to other economic sectors. There are different points of view about the function of the state in relation to cooperativism, which shows the necessity of a critical and realistic approaches about this topic that give the appropriate answer for contributing efficiently to the objectives and aspirations of the cooperative under new conditions.    In this article is presented the theoretical and methodological relationship bases between state and cooperatives, as well as the institutionalization process of this sector in different countries, including Cuba demonstrating the necessity and urgency of creating an institutional structure for the cooperative sector in Cuba that contributes to obtain a true autonomy and supervision, necessary administration support and advice. This proposal presupposes a series of premises, as well as strategic and administration elements such as: a logo, its mission, vision, structures, objectives and functions.

Active Control Of Structure-Borne Noise

Science.gov (United States)

Elliott, S. J.

1994-11-01

The successful practical application of active noise control requires an understanding of both its acoustic limitations and the limitations of the electrical control strategy used. This paper is concerned with the active control of sound in enclosures. First, a review is presented of the fundamental physical limitations of using loudspeakers to achieve either global or local control. Both approaches are seen to have a high frequency limit, due to either the acoustic modal overlap, or the spatial correlation function of the pressure field. These physical performance limits could, in principle, be achieved with either a feedback or a feedforward control strategy. These strategies are reviewed and the use of adaptive digital filters is discussed for both approaches. The application of adaptive feedforward control in the control of engine and road noise in cars is described. Finally, an indirect approach to the active control of sound is discussed, in which the vibration is suppressed in the structural paths connecting the source of vibration to the enclosure. Two specific examples of this strategy are described, using an active automotive engine mount and the incorporation of actuators into helicopter struts to control gear-meshing tones. In both cases good passive design can minimize the complexity of the active controller.

Experimental quantum control landscapes: Inherent monotonicity and artificial structure

International Nuclear Information System (INIS)

Roslund, Jonathan; Rabitz, Herschel

2009-01-01

Unconstrained searches over quantum control landscapes are theoretically predicted to generally exhibit trap-free monotonic behavior. This paper makes an explicit experimental demonstration of this intrinsic monotonicity for two controlled quantum systems: frequency unfiltered and filtered second-harmonic generation (SHG). For unfiltered SHG, the landscape is randomly sampled and interpolation of the data is found to be devoid of landscape traps up to the level of data noise. In the case of narrow-band-filtered SHG, trajectories are taken on the landscape to reveal a lack of traps. Although the filtered SHG landscape is trap free, it exhibits a rich local structure. A perturbation analysis around the top of these landscapes provides a basis to understand their topology. Despite the inherent trap-free nature of the landscapes, practical constraints placed on the controls can lead to the appearance of artificial structure arising from the resultant forced sampling of the landscape. This circumstance and the likely lack of knowledge about the detailed local landscape structure in most quantum control applications suggests that the a priori identification of globally successful (un)constrained curvilinear control variables may be a challenging task.

Proposed Framework which Uses Object Oriented Principles in Relational Systems: Structure and Formating (Part 2

Directory of Open Access Journals (Sweden)

Catalin STRIMBEI

2006-01-01

Full Text Available Our approach tries to overcome the limitations of so called “flat nature” of relational systems, in the actual context of actual relational database theories, database systems technologies and object oriented methodologies by proposing an MDA framework to map an object oriented (UML formalized model to object-relational structures of today’s database systems.

Quality Control of Concrete Structure For APR1400 Construction

International Nuclear Information System (INIS)

Seo, Inseop; Song, Changhak; Kim, Duill

2012-01-01

Nuclear structure shall be constructed to protect internal facilities in the normal operation against external accidents such as the radiation shielding, earthquakes and to be leak-proof of radioactive substances to the external environment in case of loss of coolants. containment and auxiliary building of nuclear power plants are built in reinforced concrete structures to maintain these protection functions. Nuclear structures shall be designed to ensure soundness in operation since they are located on the waterfront where is easy do drain the cooling water and so deterioration and damage of concrete structures caused by seawater can occur. Durability is ensured for concrete structures of APR1400, a Korea standard NPP, in compliance with all safety requirements. In particular, owners perform quality control directly on the production and pouring of cast in place concrete for the concrete structure construction to make sure concrete structures established with quality homogeneity and durability. This report is to look into the quality control standard and management status of cast in place concrete for APR1400 construction

Distributed voltage control and load sharing for inverter-interfaced microdrid with resistive lines

DEFF Research Database (Denmark)

Golsorkhi, Mohammad S.; Lu, D. D C; Shafiee, Q.

2016-01-01

This paper proposes a new distributed control method for coordination of distributed energy resources (DERs) in low-voltage resistive microgrids. The proposed framework consists of two level structure; primary and secondary control. Unlike the existing distributed control methods, the proposed me...

Acoustic and Vibration Control for an Underwater Structure under Mechanical Excitation

Directory of Open Access Journals (Sweden)

Shi-Jian Zhu

2014-01-01

Full Text Available Acoustic and vibration control for an underwater structure under mechanical excitation has been investigated by using negative feedback control algorithm. The underwater structure is modeled with cylindrical shells, conical shells, and circular bulkheads, of which the motion equations are built with the variational approach, respectively. Acoustic property is analyzed by the Helmholtz integration formulation with boundary element method. Based on negative feedback control algorithm, a control loop with a coupling use of piezoelectric sensor and actuator is built, and accordingly some numerical examples are carried out on active control of structural vibration and acoustic response. Effects of geometrical and material parameters on acoustic and vibration properties are investigated and discussed.

Control protocol: the proposed new CERN standard access procedure to accelerator equipment

International Nuclear Information System (INIS)

Baribaud, G.; Barnett, I.; Benincasa, G.

1992-01-01

Control protocol provides a normalized access procedure for equipment of the same kind from a control system. Modelisation and the subsequent identification of functionalities with their parameters, variables and attributes have now been carried out at CERN for representative families of devices. ISO specifications, such as the ASN.1 metalanguage for data structure representation and MMS definitions and services have, to some extent, been introduced in the design for generality and compatibility with external world. The final product of this design is totally independent of the control systems and permits object oriented implementations in any controls frame. The present paper describes the different phases of the project with a short overview of the various implementations under development at CERN. (author)

Parametric uncertainty modeling for robust control

DEFF Research Database (Denmark)

Rasmussen, K.H.; Jørgensen, Sten Bay

1999-01-01

The dynamic behaviour of a non-linear process can often be approximated with a time-varying linear model. In the presented methodology the dynamics is modeled non-conservatively as parametric uncertainty in linear lime invariant models. The obtained uncertainty description makes it possible...... to perform robustness analysis on a control system using the structured singular value. The idea behind the proposed method is to fit a rational function to the parameter variation. The parameter variation can then be expressed as a linear fractional transformation (LFT), It is discussed how the proposed...... point changes. It is shown that a diagonal PI control structure provides robust performance towards variations in feed flow rate or feed concentrations. However including both liquid and vapor flow delays robust performance specifications cannot be satisfied with this simple diagonal control structure...

Impact of structured education on glucose control and ...

African Journals Online (AJOL)

Objective: To assess the impact of structured education on glucose control and hypoglycaemia in the management of Type-2 diabetes. Methods: A systematic review was done using Medline via Ovid and EMBASE databases of published English literature between 1980 and 2014. Included studies were randomized control ...

An Automatic Control System for Conditioning 30 GHz Accelerating Structures

CERN Document Server

Dubrovskiy, A

2008-01-01

A software application programme has been developed to allow fast and automatic high-gradient conditioning of accelerating structures at 30 GHz in CTF3. The specificity of the application is the ability to control the high-power electron beam which produces the 30 GHz RF power used to condition the accelerating structures. The programme permits operation round the clock with minimum manpower requirements. In this paper the fast control system, machine control system, logging system, graphical user control interface and logging data visualization are described. An outline of the conditioning control system itself and of the feedback controlling peak power and pulse length is given. The software allows different types of conditioning strategies to be programmed

Structure-based control of complex networks with nonlinear dynamics.

Science.gov (United States)

Zañudo, Jorge Gomez Tejeda; Yang, Gang; Albert, Réka

2017-07-11

What can we learn about controlling a system solely from its underlying network structure? Here we adapt a recently developed framework for control of networks governed by a broad class of nonlinear dynamics that includes the major dynamic models of biological, technological, and social processes. This feedback-based framework provides realizable node overrides that steer a system toward any of its natural long-term dynamic behaviors, regardless of the specific functional forms and system parameters. We use this framework on several real networks, identify the topological characteristics that underlie the predicted node overrides, and compare its predictions to those of structural controllability in control theory. Finally, we demonstrate this framework's applicability in dynamic models of gene regulatory networks and identify nodes whose override is necessary for control in the general case but not in specific model instances.

Optically controlled photonic bandgap structures for microstrip circuits

International Nuclear Information System (INIS)

Cadman, Darren Arthur

2003-01-01

This thesis is concerned with the optical control of microwave photonic bandgap circuits using high resistivity silicon. Photoconducting processes that occur within silicon are investigated. The influence of excess carrier density on carrier mobility and lifetime is examined. In addition, electron-hole pair recombination mechanisms (Shockley-Read-Hall, Auger, radiative and surface) are investigated. The microwave properties of silicon are examined, in particular the variation of silicon reflectivity with excess carrier density. Filtering properties of microstrip photonic bandgap structures and how they may be controlled optically are studied. A proof-of-concept microstrip photonic bandgap structure with optical control is designed, simulated and measured. With no optical illumination incident upon the silicon, the microstrip photonic bandgap structure's filtering properties are well-defined; a 3dB stopband width of 2.6GHz, a 6dB bandwidth of 2GHz and stopband depth of -11.6dB at the centre frequency of 9.9GHz. When the silicon is illuminated, the structure's filtering properties are suppressed. Under illumination the experimental results display an increase in S 21 of 6.5dB and a reduction in S 11 of more than 10dB at 9.9GHz. A comparison of measured and simulated results reveal that the photogenerated excess carrier density is between 4 x 10 15 cm -3 and 1.1 x 10 16 cm -3 . (author)

Comparison of various decentralised structural and cavity feedback control strategies for transmitted noise reduction through a double panel structure

NARCIS (Netherlands)

Ho, J.; Berkhoff, Arthur P.

This paper compares various decentralised control strategies, including structural and acoustic actuator–sensor configuration designs, to reduce noise transmission through a double panel structure. The comparison is based on identical control stability indexes. The double panel structure consists of

Comparison of various decentralised structural and cavity feedback control strategies for transmitted noise reduction through a double panel structure

NARCIS (Netherlands)

Ho, J.H.; Berkhoff, A.P.

2014-01-01

This paper compares various decentralised control strategies, including structural and acoustic actuator-sensor configuration designs, to reduce noise transmission through a double panel structure. The comparison is based on identical control stability indexes. The double panel structure consists of

Accurately controlled sequential self-folding structures by polystyrene film

Science.gov (United States)

Deng, Dongping; Yang, Yang; Chen, Yong; Lan, Xing; Tice, Jesse

2017-08-01

Four-dimensional (4D) printing overcomes the traditional fabrication limitations by designing heterogeneous materials to enable the printed structures evolve over time (the fourth dimension) under external stimuli. Here, we present a simple 4D printing of self-folding structures that can be sequentially and accurately folded. When heated above their glass transition temperature pre-strained polystyrene films shrink along the XY plane. In our process silver ink traces printed on the film are used to provide heat stimuli by conducting current to trigger the self-folding behavior. The parameters affecting the folding process are studied and discussed. Sequential folding and accurately controlled folding angles are achieved by using printed ink traces and angle lock design. Theoretical analyses are done to guide the design of the folding processes. Programmable structures such as a lock and a three-dimensional antenna are achieved to test the feasibility and potential applications of this method. These self-folding structures change their shapes after fabrication under controlled stimuli (electric current) and have potential applications in the fields of electronics, consumer devices, and robotics. Our design and fabrication method provides an easy way by using silver ink printed on polystyrene films to 4D print self-folding structures for electrically induced sequential folding with angular control.

Bedfordshire County Structure Plan. Proposed alterations. Results of public consultation. Policy 97: Nuclear waste

International Nuclear Information System (INIS)

1984-01-01

The document refers to Alterations to the County Structure Plan, proposed by Bedfordshire County Council and submitted to the Secretary of State for the Environment. An additional Alteration initiated at the County Council's meeting, dealing with nuclear waste, had not been the subject of prior public consultation. Consultation had since been arranged, and the present document summarises the responses that have been received, and describes the next action to be taken. (U.K.)

Optimization of controllability and robustness of complex networks by edge directionality

Science.gov (United States)

Liang, Man; Jin, Suoqin; Wang, Dingjie; Zou, Xiufen

2016-09-01

Recently, controllability of complex networks has attracted enormous attention in various fields of science and engineering. How to optimize structural controllability has also become a significant issue. Previous studies have shown that an appropriate directional assignment can improve structural controllability; however, the evolution of the structural controllability of complex networks under attacks and cascading has always been ignored. To address this problem, this study proposes a new edge orientation method (NEOM) based on residual degree that changes the link direction while conserving topology and directionality. By comparing the results with those of previous methods in two random graph models and several realistic networks, our proposed approach is demonstrated to be an effective and competitive method for improving the structural controllability of complex networks. Moreover, numerical simulations show that our method is near-optimal in optimizing structural controllability. Strikingly, compared to the original network, our method maintains the structural controllability of the network under attacks and cascading, indicating that the NEOM can also enhance the robustness of controllability of networks. These results alter the view of the nature of controllability in complex networks, change the understanding of structural controllability and affect the design of network models to control such networks.

Design of a new PID controller using predictive functional control optimization for chamber pressure in a coke furnace.

Science.gov (United States)

Zhang, Jianming

2017-03-01

An improved proportional-integral-derivative (PID) controller based on predictive functional control (PFC) is proposed and tested on the chamber pressure in an industrial coke furnace. The proposed design is motivated by the fact that PID controllers for industrial processes with time delay may not achieve the desired control performance because of the unavoidable model/plant mismatches, while model predictive control (MPC) is suitable for such situations. In this paper, PID control and PFC algorithm are combined to form a new PID controller that has the basic characteristic of PFC algorithm and at the same time, the simple structure of traditional PID controller. The proposed controller was tested in terms of set-point tracking and disturbance rejection, where the obtained results showed that the proposed controller had the better ensemble performance compared with traditional PID controllers. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Proposed quality control guidelines for National Committee for Clinical Laboratory Standards Susceptibility Tests using the veterinary antimicrobial agent tiamulin.

Science.gov (United States)

Pfaller, M A; Jones, R N; Walter, D H

2001-01-01

Quality control guidelines for standardized antimicrobial susceptibility test methods are critical for the continuing accuracy of these clinical tests. In this report, quality control limits were proposed for the veterinary antimicrobial agent tiamulin with minimum inhibitory concentration (MIC) ranges of three or four log(2) dilution steps in two different medium formulations. Disk diffusion zone diameter ranges were proposed for tiamulin tested against Actinobacillus pleuropneumoniae ATCC 27090 (12-18 mm) and Staphylococcus aureus ATCC 25923 (25-32 mm). The data from eight participating laboratories produced 100% of results within proposed MIC limits (8-32 microg/mL), and 95.8-97.0% of zones were found within suggested zone diameter QC guidelines. These proposed QC ranges should be validated by in-use results from veterinary clinical laboratories.

Hierarchical, decentralized control system for large-scale smart-structures

International Nuclear Information System (INIS)

Algermissen, Stephan; Fröhlich, Tim; Monner, Hans Peter

2014-01-01

Active control of sound and vibration has gained much attention in all kinds of industries in the past decade. Future prospects for maximizing airline passenger comfort are especially promising. The objectives of recent research projects in this area are the reduction of noise transmission through thin walled structures such as fuselages, linings or interior elements. Besides different external noise sources, such as the turbulent boundary layer, rotor or jet noise, the actuator and sensor placement as well as different control concepts are addressed. Mostly, the work is focused on a single panel or section of the fuselage, neglecting the fact that for effective noise reduction the entire fuselage has to be taken into account. Nevertheless, extending the scope of an active system from a single panel to the entire fuselage increases the effort for control hardware dramatically. This paper presents a control concept for large structures using distributed control nodes. Each node has the capability to execute a vibration or noise controller for a specific part or section of the fuselage. For maintenance, controller tuning or performance measurement, all nodes are connected to a host computer via Universal Serial Bus (USB). This topology allows a partitioning and distributing of tasks. The nodes execute the low-level control functions. High-level tasks like maintenance, system identification and control synthesis are operated by the host using streamed data from the nodes. By choosing low-price nodes, a very cost effective way of implementing an active system for large structures is realized. Besides the system identification and controller synthesis on the host computer, a detailed view on the hardware and software concept for the nodes is given. Finally, the results of an experimental test of a system running a robust vibration controller at an active panel demonstrator are shown. (paper)

Proposed Framework which Uses Object Oriented Principles in Relational Systems: Structure and Formating (Part 2)

OpenAIRE

Catalin STRIMBEI

2006-01-01

Our approach tries to overcome the limitations of so called “flat nature†of relational systems, in the actual context of actual relational database theories, database systems technologies and object oriented methodologies by proposing an MDA framework to map an object oriented (UML formalized) model to object-relational structures of today’s database systems.

7 CFR 4290.440 - Standards governing prior approval for a proposed transfer of Control.

Science.gov (United States)

2010-01-01

... BUSINESS INVESTMENT COMPANY (âRBICâ) PROGRAM Changes in Ownership, Structure, or Control Changes in Control... Person(s) to assume, in writing, personal liability for your Leverage, effective only in the event of... requirements for minimum capital and management-ownership diversity in effect at such time for new RBICs. ...

Fault Tolerant Flight Control Using Sliding Modes and Subspace Identification-Based Predictive Control

KAUST Repository

Siddiqui, Bilal A.; El-Ferik, Sami; Abdelkader, Mohamed

2016-01-01

In this work, a cascade structure of a time-scale separated integral sliding mode and model predictive control is proposed as a viable alternative for fault-tolerant control. A multi-variable sliding mode control law is designed as the inner loop of the flight control system. Subspace identification is carried out on the aircraft in closed loop. The identified plant is then used for model predictive controllers in the outer loop. The overall control law demonstrates improved robustness to measurement noise, modeling uncertainties, multiple faults and severe wind turbulence and gusts. In addition, the flight control system employs filters and dead-zone nonlinear elements to reduce chattering and improve handling quality. Simulation results demonstrate the efficiency of the proposed controller using conventional fighter aircraft without control redundancy.

Fault Tolerant Flight Control Using Sliding Modes and Subspace Identification-Based Predictive Control

KAUST Repository

Siddiqui, Bilal A.

2016-07-26

In this work, a cascade structure of a time-scale separated integral sliding mode and model predictive control is proposed as a viable alternative for fault-tolerant control. A multi-variable sliding mode control law is designed as the inner loop of the flight control system. Subspace identification is carried out on the aircraft in closed loop. The identified plant is then used for model predictive controllers in the outer loop. The overall control law demonstrates improved robustness to measurement noise, modeling uncertainties, multiple faults and severe wind turbulence and gusts. In addition, the flight control system employs filters and dead-zone nonlinear elements to reduce chattering and improve handling quality. Simulation results demonstrate the efficiency of the proposed controller using conventional fighter aircraft without control redundancy.

Active vibration control of smart hull structure using piezoelectric composite actuators

International Nuclear Information System (INIS)

Sohn, Jung Woo; Choi, Seung-Bok; Lee, Chul-Hee

2009-01-01

In this paper, active vibration control performance of the smart hull structure with macro-fiber composite (MFC) is evaluated. MFC is an advanced piezoelectric composite which has great flexibility and increased actuating performance compared to a monolithic piezoelectric ceramic patch. The governing equations of motion of the hull structure with MFC actuators are derived based on the classical Donnell–Mushtari shell theory. The actuating model for the interaction between hull structure and MFC is included in the governing equations. Subsequently, modal characteristics are investigated and compared with the results obtained from experiment. The governing equations of the vibration control system are then established and expressed in the state space form. A linear quadratic Gaussian (LQG) control algorithm is designed in order to effectively and actively control the imposed vibration. The controller is experimentally realized and vibration control performances are evaluated

Proposal for an ecoradiological centre model

International Nuclear Information System (INIS)

Perovic, S.M.; Zunic, Z.; Demajo, M.; Konjevic, N.

1998-01-01

The problem of establishing an optimal Ecoradiological Centre Model is studied in some detail for the town of Kotor which is under the protection of the World Cultural and Natural Heritage. The proposed structure of the Centre is analyzed from the view of Engineering, Education and Scientific parameters. This Model is suitable for implementation as a network Centre Model for the state of Montenegro. Further, the modelling strategy of the ecoradiological condition control of natural, construction, bio and technological systems is elaborated. The proposal includes the ecoradiological monitoring, radioactive and electromagnetic radiation processing and protection for different natural zones as well as their different geostructures, aerial and hydrogeological conditions. The programme also includes all housing objects (hotels, flats, houses, office premises etc.). Here will also be presented the radiation protection and recommendations for the implementation of Title VII of the European Basic Safety Standards Directive (BSS), concerning significant increase in exposure due to natural radiation sources. Also, the proposal of Local Radiation Protection for the town of Kotor is presented. Our proposal for an Ecoradiological Centre Model presented here is in a form of a pilot programme, applicable also for other towns and states. (author)

Analysis of Reconfigured Control Loop with a Virtual Actuator

Directory of Open Access Journals (Sweden)

Anna Filasova

2011-01-01

Full Text Available Control reconfiguration changes the control structure in response to a fault detected in the plant. This becomes necessary, because a major fault like loss of an actuator breaks the corresponding control loop and therefore renders the whole system inoperable.  An important aim of control reconfiguration is to change the control structure as little as possible, since every change bears the potential of practical problems. The proposed solution is to keep the original controller in the loop and to add an extension called virtual actuator that implements the necessary changes of the control structure. The virtual actuator translates between the signals of the nominal controller and the signal of the faulty plants. This paper is concerned with the analysis of reconfigured loop with a virtual actuator for the system with the faulty actuator. The proposed analysis is illustrated on numerical example.

Deformation compatibility control for engineering structures methods and applications

CERN Document Server

Zhu, Hanhua; Chen, Mengchong; Deng, Jianliang

2017-01-01

This book presents essential methods of deformation compatibility control, and explicitly addresses the implied conditions on the methods’ deformation compatibility. Consequently, these conditions can be considered in engineering structure design, while the conditions on stable equilibrium can be taken into account in the design method. Thus, the designed deformation and the actual deformation of the respective structure are approximately identical, guaranteeing both the flexibility of the construction material in force transmission and the equilibrium of force in the structure. Though equilibrium theory in engineering structures has been extensively studied, there has been comparatively little research on compatibility. In the limited researches available, the topics are primarily the theories and assumptions on the deformation compatibility, while few systematic works focus on the mechanical theoretical principles and methods of deformation compatibility control. As such, the flexibility of the constructi...

The structure and operation scheme of an automatic and supervisory control system for KEPCO UPFC

Energy Technology Data Exchange (ETDEWEB)

Ahn, S.J.; Lee, D.W.; Moon, S.I. [Seoul National Univ., Seoul (Korea, Republic of). School of Electrical Engineering

2007-07-01

The structure and functions of a control system that can be used for automatic and supervisory control of a unified power flow controller (UPFC) was presented. A UPFC is a device used in power electronic based transmission to allow the independent control of active and reactive power flows as well as the simultaneous control of voltage profile. The Korea Electric Power Corporation (KEPCO) installed a {+-}80 MVA UPFC at the 154 kV Kangjin substation, operated in the Kangjin-Jangheung transmission line. The operation strategies used in both the normal state and emergency state were presented along with a scheme that includes the minimization of active power loss, coordination of voltage/Var control with an under load tap changer (ULTC), and better system security. Although this UPFC is operated by set-point control, it has some limitations, particularly in emergency events. In order to overcome the limitation of set-point control, this paper proposed the automatic and supervisory control system connected to a local SCADA for data exchange. The primary function of the system is to analyze the state of the power system, determine the control objectives and to calculate the optimal power flow. Details of each of these functions was described in this paper along with a detailed algorithm for each scheme. 5 refs., 6 figs.

Skin lipid structure controls water permeability in snake molts.

Science.gov (United States)

Torri, Cristian; Mangoni, Alfonso; Teta, Roberta; Fattorusso, Ernesto; Alibardi, Lorenzo; Fermani, Simona; Bonacini, Irene; Gazzano, Massimo; Burghammer, Manfred; Fabbri, Daniele; Falini, Giuseppe

2014-01-01

The role of lipids in controlling water exchange is fundamentally a matter of molecular organization. In the present study we have observed that in snake molt the water permeability drastically varies among species living in different climates and habitats. The analysis of molts from four snake species: tiger snake, Notechis scutatus, gabon viper, Bitis gabonica, rattle snake, Crotalus atrox, and grass snake, Natrix natrix, revealed correlations between the molecular composition and the structural organization of the lipid-rich mesos layer with control in water exchange as a function of temperature. It was discovered, merging data from micro-diffraction and micro-spectroscopy with those from thermal, NMR and chromatographic analyses, that this control is generated from a sophisticated structural organization that changes size and phase distribution of crystalline domains of specific lipid molecules as a function of temperature. Thus, the results of this research on four snake species suggest that in snake skins different structured lipid layers have evolved and adapted to different climates. Moreover, these lipid structures can protect, "safety", the snakes from water lost even at temperatures higher than those of their usual habitat. Copyright © 2013 Elsevier Inc. All rights reserved.

Describing qualitative research undertaken with randomised controlled trials in grant proposals: a documentary analysis.

Science.gov (United States)

Drabble, Sarah J; O'Cathain, Alicia; Thomas, Kate J; Rudolph, Anne; Hewison, Jenny

2014-02-18

There is growing recognition of the value of conducting qualitative research with trials in health research. It is timely to reflect on how this qualitative research is presented in grant proposals to identify lessons for researchers and research commissioners. As part of a larger study focusing on how to maximise the value of undertaking qualitative research with trials, we undertook a documentary analysis of proposals of funded studies. Using the metaRegister of Controlled Trials (mRCT) database we identified trials funded in the United Kingdom, ongoing between 2001 and 2010, and reporting the use of qualitative research. We requested copies of proposals from lead researchers. We extracted data from the proposals using closed and open questions, analysed using descriptive statistics and content analysis respectively. 2% (89/3812) of trials in the mRCT database described the use of qualitative research undertaken with the trial. From these 89 trials, we received copies of 36 full proposals, of which 32 met our inclusion criteria. 25% used less than a single paragraph to describe the qualitative research. The aims of the qualitative research described in these proposals focused mainly on the intervention or trial conduct. Just over half (56%) of the proposals included an explicit rationale for conducting the qualitative research with the trial, the most frequent being to optimise implementation into clinical practice or to interpret trial findings. Key information about methods, expertise and resources was missing in a large minority of proposals, in particular sample size, type of analysis, and non-personnel resources. 28% specifically stated that qualitative researchers would conduct the qualitative research. Our review of proposals of successfully funded studies identified good practice but also identified limited space given to describing the qualitative research, with an associated lack of attention to the rationale for doing the qualitative research and

The Influence of PZT Actuators Positioning in Active Structural Acoustic Control

Directory of Open Access Journals (Sweden)

P. Švec

2007-01-01

Full Text Available This paper deals with the effect of secondary actuator positioning in an active structural acoustics control (ASAC experiment. The ASAC approach is based on minimizing the sound radiation from structures to the far field by controlling the structural vibrations. In this article a rectangular steel plate structure was assumed with one secondary actuator attached to it. As a secondary actuator, a specially designed piezoelectric stripe actuator was used. We studied the effect of the position of the actuator on the pattern and on the radiated sound field of the structural vibration, with and without active control. The total radiated power was also measured. The experimental data was confronted with the results obtained by a numerical solution of the mathematical model used. For the solution, the finite element method in the ANSYS software package was used. 

Damage tolerance and structural monitoring for wind turbine blades

DEFF Research Database (Denmark)

McGugan, Malcolm; Pereira, Gilmar Ferreira; Sørensen, Bent F.

2015-01-01

The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation it will b......The paper proposes a methodology for reliable design and maintenance of wind turbine rotor blades using a condition monitoring approach and a damage tolerance index coupling the material and structure. By improving the understanding of material properties that control damage propagation...

Concept study of a novel energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) device for vibration control of harmonically-excited structures

International Nuclear Information System (INIS)

Salvi, Jonathan; Giaralis, Agathoklis

2016-01-01

A novel dynamic vibration absorber (DVA) configuration is introduced for simultaneous vibration suppression and energy harvesting from oscillations typically exhibited by large-scale low-frequency engineering structures and structural components. The proposed configuration, termed energy harvesting-enabled tuned mass-damper-inerter (EH-TMDI) comprises a mass grounded via an in-series electromagnetic motor (energy harvester)-inerter layout, and attached to the primary structure through linear spring and damper in parallel connection. The governing equations of motion are derived and solved in the frequency domain, for the case of harmonically-excited primary structures, here modelled as damped single-degree- of-freedom (SDOF) systems. Comprehensive parametric analyses proved that by varying the mass amplification property of the grounded inerter, and by adjusting the stiffness and the damping coefficients using simple optimum tuning formulae, enhanced vibration suppression (in terms of primary structure peak displacement) and energy harvesting (in terms of relative velocity at the terminals of the energy harvester) may be achieved concurrently and at nearresonance frequencies, for a fixed attached mass. Hence, the proposed EH-TMDI allows for relaxing the trade-off between vibration control and energy harvesting purposes, and renders a dual-objective optimisation a practically-feasible, reliable task. (paper)

OPTICON: Pro-Matlab software for large order controlled structure design

Science.gov (United States)

Peterson, Lee D.

1989-01-01

A software package for large order controlled structure design is described and demonstrated. The primary program, called OPTICAN, uses both Pro-Matlab M-file routines and selected compiled FORTRAN routines linked into the Pro-Matlab structure. The program accepts structural model information in the form of state-space matrices and performs three basic design functions on the model: (1) open loop analyses; (2) closed loop reduced order controller synthesis; and (3) closed loop stability and performance assessment. The current controller synthesis methods which were implemented in this software are based on the Generalized Linear Quadratic Gaussian theory of Bernstein. In particular, a reduced order Optimal Projection synthesis algorithm based on a homotopy solution method was successfully applied to an experimental truss structure using a 58-state dynamic model. These results are presented and discussed. Current plans to expand the practical size of the design model to several hundred states and the intention to interface Pro-Matlab to a supercomputing environment are discussed.

Conceptual proposals for measuring the impact of international regimes on energy security

International Nuclear Information System (INIS)

Sander, Michael

2013-01-01

The paper proposes two concepts to assess the effect of international regimes on energy security. Existing indicators focus mainly on state-level factors, excluding international influences. International relation scholars on the other hand see a clear connection between international regimes and stable energy relations. International regimes stabilise energy relations by providing frameworks for negotiations, defining, controlling and sanctioning compliance and allowing the actors to engage in package deals. The researcher needs to include these factors in a complete assessment of political energy security risks. As first step, the paper uses the effectiveness of control mechanisms as basis for such consideration. It refers specifically to international arbitration as the most important control mechanism in international energy relations. The simplest measurement option is the share of a county's energy imports covered by a certain regime. The paper applies the Oslo-Potsdam-Solution to account for outcome effectiveness. It applies a variant of the International Regimes Data Base protocol to account for effective regime structures. In a last section, the paper proposes some possible paths for future research. - Highlights: • International regimes mitigate political risks for energy supply and must be considered. • The paper proposes two concepts to measure energy regime effectiveness. • The OPS-variant measures output, the IRDB-variant measures structure effectiveness. • The paper offers a preliminary feasibility test for the concepts. • Finally, it suggests further roads for research

Coupling Mechanism and Decoupled Suspension Control Model of a Half Car

Directory of Open Access Journals (Sweden)

Hailong Zhang

2016-01-01

Full Text Available A structure decoupling control strategy of half-car suspension is proposed to fully decouple the system into independent front and rear quarter-car suspensions in this paper. The coupling mechanism of half-car suspension is firstly revealed and formulated with coupled damping force (CDF in a linear function. Moreover, a novel dual dampers-based controllable quarter-car suspension structure is proposed to realize the independent control of pitch and vertical motions of the half car, in which a newly added controllable damper is suggested to be installed between the lower control arm and connection rod in conventional quarter-car suspension structure. The suggested damper constantly regulates the half-car pitch motion posture in a smooth and steady operation condition meantime achieving the expected completely structure decoupled control of the half-car suspension, by compensating the evolved CDF.

Diode rectifier bridge-based structure for DFIG-based wind turbine

DEFF Research Database (Denmark)

Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

2015-01-01

This paper proposes a new structure for the doubly-fed induction generator (DFIG)-based wind turbine. The proposed structure consists of a DFIG controlled by a partial rated power converter in the rotor side, a three-phase diode rectifier bridge (DRB) connected to the stator, and a DC/AC full rated...

Reactors licensing: proposal of an integrated quality and environment regulatory structure for nuclear research reactors in Brazil

International Nuclear Information System (INIS)

Serra, Reynaldo Cavalcanti

2014-01-01

A new integrated regulatory structure based on quality and integrated issues has been proposed to be implemented on the licensing process of nuclear research reactors in Brazil. The study starts with a literature review about the licensing process in several countries, all of them members of the International Atomic Energy Agency. After this phase it is performed a comparative study with the Brazilian licensing process to identify good practices (positive aspects), the gaps on it and to propose an approach of an integrated quality and environmental management system, in order to contribute with a new licensing process scheme in Brazil. The literature review considered the following research nuclear reactors: Jules-Horowitz and OSIRIS (France), Hanaro (Korea), Maples 1 and 2 (Canada), OPAL (Australia), Pallas (Holand), ETRR-2 (Egypt) and IEA-R1 (Brazil). The current nuclear research reactors licensing process in Brazil is conducted by two regulatory bodies: the Brazilian National Nuclear Energy Commission (CNEN) and the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA). CNEN is responsible by nuclear issues, while IBAMA by environmental one. To support the study it was applied a questionnaire and interviews based on the current regulatory structure to four nuclear research reactors in Brazil. Nowadays, the nuclear research reactor’s licensing process, in Brazil, has six phases and the environmental licensing process has three phases. A correlation study among these phases leads to a proposal of a new quality and environmental integrated licensing structure with four harmonized phases, hence reducing potential delays in this process. (author)

Didactic System for the Experimental Study of Digital PID Control Structures

OpenAIRE

Stelian-Emilian OLTEAN; Mircea DULĂU; Adrian-Vasile DUKA

2016-01-01

The proportional integral derivative (PID) controller has a known structure used in feedback control of industrial processes. One of the most common applications is the control of the DC motor. The paper presents a didactic system designed for educational purposes used for studying various conventional PID structures and the influence of the PID components in the control process of the DC motor’s speed. The system contains a low cost acquisition board based on PIC 16F628A microcontroller. The...

Structural characteristics of proposed ITER [International Thermonuclear Experimental Reactor] TF [toroidal field] coil conductor

International Nuclear Information System (INIS)

Gibson, C.R.; Miller, J.R.

1988-01-01

This paper analyzes the effect of transverse loading on a cable-in-conduit conductor which has been proposed for the toroidal field coils of the International Thermonuclear Experimental Reactor. The primary components of this conductor are a loose cable of superconducting wires, a thin-wall tube for helium containment, and a U-shaped structural channel. A method is given where the geometry of this conductor can be optimized for a given set of operating conditions. It is shown, using finite-element modeling, that the structural channel is effective in supporting loads due to transverse forces and internal pressure. In addition, it is shown that the superconducting cable is effectively shielded from external transverse loads that might otherwise degrade its current carrying capacity. 10 refs., 10 figs., 3 tabs

A multi-mode operation control strategy for flexible microgrid based on sliding-mode direct voltage and hierarchical controls.

Science.gov (United States)

Zhang, Qinjin; Liu, Yancheng; Zhao, Youtao; Wang, Ning

2016-03-01

Multi-mode operation and transient stability are two problems that significantly affect flexible microgrid (MG). This paper proposes a multi-mode operation control strategy for flexible MG based on a three-layer hierarchical structure. The proposed structure is composed of autonomous, cooperative, and scheduling controllers. Autonomous controller is utilized to control the performance of the single micro-source inverter. An adaptive sliding-mode direct voltage loop and an improved droop power loop based on virtual negative impedance are presented respectively to enhance the system disturbance-rejection performance and the power sharing accuracy. Cooperative controller, which is composed of secondary voltage/frequency control and phase synchronization control, is designed to eliminate the voltage/frequency deviations produced by the autonomous controller and prepare for grid connection. Scheduling controller manages the power flow between the MG and the grid. The MG with the improved hierarchical control scheme can achieve seamless transitions from islanded to grid-connected mode and have a good transient performance. In addition the presented work can also optimize the power quality issues and improve the load power sharing accuracy between parallel VSIs. Finally, the transient performance and effectiveness of the proposed control scheme are evaluated by theoretical analysis and simulation results. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Modeling and control of flexible space structures

Science.gov (United States)

Wie, B.; Bryson, A. E., Jr.

1981-01-01

The effects of actuator and sensor locations on transfer function zeros are investigated, using uniform bars and beams as generic models of flexible space structures. It is shown how finite element codes may be used directly to calculate transfer function zeros. The impulse response predicted by finite-dimensional models is compared with the exact impulse response predicted by the infinite dimensional models. It is shown that some flexible structures behave as if there were a direct transmission between actuator and sensor (equal numbers of zeros and poles in the transfer function). Finally, natural damping models for a vibrating beam are investigated since natural damping has a strong influence on the appropriate active control logic for a flexible structure.

Organizational models as configurations of structure, culture, leadership, control, and change strategy

Directory of Open Access Journals (Sweden)

Janićijević Nebojša

2017-01-01

Full Text Available Starting from the axioms of consistency, stability, contingency, and configuration, research on organizational structure, culture, control, leadership, and change management strategy has shown that their typical configurations, or models, can be differentiated according to the same two criteria: distribution of power and dominant organizational dimension. On the one hand there are models of structure, culture, control, leadership, and change management strategy that are based on an unequal, or authoritarian, distribution of power within organizations, while on the other hand there are models that are based on democratic, or equal, distribution of power. Also, on the one hand there are models of structure, culture, control, leadership, and change strategy that are based on work structure and tasks, while on the other hand there are models of these organizational components that are based on social structure, people, and their relationships. Harmonization of typical configurations of organizational structure, culture, control, leadership, and change strategy occurs due to the harmonization of the differentiation criteria. Based on this harmonization, four organizational models have been identified as typical configurations of structure, culture, control, leadership, and change strategy: the autocratic, bureaucratic, innovative, and task models. Each of these models is effective in a different environmental contingency.

Proposal of many-party controlled teleportation for multi-qubit entangled W state

Institute of Scientific and Technical Information of China (English)

Huang Zhi-Ping; Li Hong-Cai

2005-01-01

A scheme of M-party controlled teleportation for one N-qubit entangled W state via (N-1) Einstein-PodolskyRosen (EPR) pairs and one (M+2)-qubit Greenberger-Horne-Zeilinger (GHZ) state is proposed. We achieve the teleportation in such a way that M agents can execute the Hadamard transformation, perform the measurement on their qubits and inform the receiver of their measurements. Then we discuss that the receiver cannot fully recover the state from the sender if one agent does not co-operate with him.

Structural Control of a Wind Turbine Accounting for Second Order Effects

Science.gov (United States)

Caterino, Nicola; Spizzuoco, Mariacristina

2017-10-01

The negative impact of the use of fossil fuels on the environment has lead to a boom in the production of wind turbines. The progressively increasing turbines’ height, decided to take ad-vantage of the smoother winds at higher altitude, has led to an increased demand to control tower forces. The proposed work is focused on the application of a semi-active (SA) control system to limit bending moment demand at the base of a wind turbine by relaxing the base restraint of the turbine’s tower, without increasing the top displacement. The proposed SA control system reproduces a variable restraint at the base that changes in real time its mechanical properties according to the instantaneous response of the turbine’s tower. This smart restraint is made of a central smooth hinge, elastic springs and SA magnetorheological dampers driven by a properly designed control algorithm. A commercial 105 m tall wind turbine has been considered as a case study. Several numerical simulations have been performed with reference to two extreme loads, different one each other for intensity, duration, frequency content, so as to understand if a unique optimal configuration of the controller can be defined for both of them. The proposed study is also focused on understanding whether and how to reduce the residual top displacement due to the possible incremental base rotation that may happen during a wind load history, especially when it is long lasting.

Structured Kernel Subspace Learning for Autonomous Robot Navigation.

Science.gov (United States)

Kim, Eunwoo; Choi, Sungjoon; Oh, Songhwai

2018-02-14

This paper considers two important problems for autonomous robot navigation in a dynamic environment, where the goal is to predict pedestrian motion and control a robot with the prediction for safe navigation. While there are several methods for predicting the motion of a pedestrian and controlling a robot to avoid incoming pedestrians, it is still difficult to safely navigate in a dynamic environment due to challenges, such as the varying quality and complexity of training data with unwanted noises. This paper addresses these challenges simultaneously by proposing a robust kernel subspace learning algorithm based on the recent advances in nuclear-norm and l 1 -norm minimization. We model the motion of a pedestrian and the robot controller using Gaussian processes. The proposed method efficiently approximates a kernel matrix used in Gaussian process regression by learning low-rank structured matrix (with symmetric positive semi-definiteness) to find an orthogonal basis, which eliminates the effects of erroneous and inconsistent data. Based on structured kernel subspace learning, we propose a robust motion model and motion controller for safe navigation in dynamic environments. We evaluate the proposed robust kernel learning in various tasks, including regression, motion prediction, and motion control problems, and demonstrate that the proposed learning-based systems are robust against outliers and outperform existing regression and navigation methods.

Optimization strategy for actuator and sensor placement in active structural acoustic control

NARCIS (Netherlands)

Oude nijhuis, M.H.H.; de Boer, Andries

2003-01-01

In active structural acoustic control the goal is to reduce the sound radiation of a structure by means of changing the vibrational behaviour of that structure. The performance of such an active control system is to a large extent determined by the locations of the actuators and sensors. In this

Active Vibration Control of a Monopile Offshore Structure

DEFF Research Database (Denmark)

Nielsen, Søren R. K.; Kirkegaard, Poul Henning; Thesbjerg, L.

1996-01-01

coefficient should be obtained in order to have a relatively small excitation on the cylinder. The drag coefficient can be controlled if the separation points of the boundary layers can be controlled. It is proposed to control the separation points by blowing compressed air out of the holes in the cylinder....... If the natura1 separation points of the boundary layers are rejected by blowing air out of the holes the drag coefficient will increase while it will decrease if it is possible to attach the boundary layer. The results from the experimental test have shown that it is possible to increase the drag coefficient...... with a factor 1.5-2 by blowing air out of the holes in a cylinder vibrating in a stationary water flow....

Active structural acoustic control of noise transmission through double panel systems

Science.gov (United States)

Carneal, James P.; Fuller, Chris R.

1995-04-01

A preliminary parametric study of active control of sound transmission through double panel systems has been experimentally performed. The technique used is the active structural acoustic control (ASAC) approach where control inputs, in the form of piezoelectric actuators, were applied to the structure while the radiated pressure field was minimized. Results indicate the application of control inputs to the radiating panel resulted in greater transmission loss due to its direct effect on the nature of the structural-acoustic coupling between the radiating panel and the receiving chamber. Increased control performance was seen in a double panel system consisting of a stiffer radiating panel with a lower modal density. As expected, more effective control of a radiating panel excited on-resonance is achieved over one excited off-resonance. In general, the results validate the ASAC approach for double panel systems and demonstrate that it is possible to take advantage of double panel behavior to enhance control performance, although it is clear that further research must be done to understand the physics involved.

A proposal for off-grid photovoltaic systems with non-controllable loads using fuzzy logic

International Nuclear Information System (INIS)

Yahyaoui, Imene; Sallem, Souhir; Kamoun, M.B.A.; Tadeo, Fernando

2014-01-01

Highlights: • An energy management system is proposed for off-grid PV systems, based on fuzzy logic. • The proposal guarantees the energy balance and battery protection. • The approach is demonstrated using data measured at the target location. - Abstract: A fuzzy-logic based methodology is proposed and evaluated for energy management in off-grid installations with photovoltaic panels as the source of energy and a limited storage capacity in batteries. The decision on the connection or disconnection of components is based on fuzzy rules on the basis of the Photovoltaic Panel Generation measurement, the measured power required by the load, and the estimation of the stored energy in the batteries (this last is obtained from the estimation of the Depth-of-Discharge). The algorithm aims to ensure the system’s autonomy by controlling the switches linking the system components with respect to a multi-objective management criterion developed from the requirements (supply of the load, protection of the battery, etc.). Detailed tests of the proposed system are carried out using data (irradiation, temperature, power consumption, etc.) measured in a household at the target area at several days of the year. The results demonstrate that the proposed approach achieves the objectives of system autonomy, battery protection and power supply stability. Compared with a basic algorithm, the proposed algorithm is not sensitive to sudden changes in atmospheric parameters and avoids overcharging the battery

Grain Structure Control of Additively Manufactured Metallic Materials

Directory of Open Access Journals (Sweden)

Fuyao Yan

2017-11-01

Full Text Available Grain structure control is challenging for metal additive manufacturing (AM. Grain structure optimization requires the control of grain morphology with grain size refinement, which can improve the mechanical properties of additive manufactured components. This work summarizes methods to promote fine equiaxed grains in both the additive manufacturing process and subsequent heat treatment. Influences of temperature gradient, solidification velocity and alloy composition on grain morphology are discussed. Equiaxed solidification is greatly promoted by introducing a high density of heterogeneous nucleation sites via powder rate control in the direct energy deposition (DED technique or powder surface treatment for powder-bed techniques. Grain growth/coarsening during post-processing heat treatment can be restricted by presence of nano-scale oxide particles formed in-situ during AM. Grain refinement of martensitic steels can also be achieved by cyclic austenitizing in post-processing heat treatment. Evidently, new alloy powder design is another sustainable method enhancing the capability of AM for high-performance components with desirable microstructures.

Action selection in growing state spaces: control of network structure growth

International Nuclear Information System (INIS)

Thalmeier, Dominik; Kappen, Hilbert J; Gómez, Vicenç

2017-01-01

The dynamical processes taking place on a network depend on its topology. Influencing the growth process of a network therefore has important implications on such dynamical processes. We formulate the problem of influencing the growth of a network as a stochastic optimal control problem in which a structural cost function penalizes undesired topologies. We approximate this control problem with a restricted class of control problems that can be solved using probabilistic inference methods. To deal with the increasing problem dimensionality, we introduce an adaptive importance sampling method for approximating the optimal control. We illustrate this methodology in the context of formation of information cascades, considering the task of influencing the structure of a growing conversation thread, as in Internet forums. Using a realistic model of growing trees, we show that our approach can yield conversation threads with better structural properties than the ones observed without control. (paper)

76 FR 70829 - Proposed Information Collection (Architect-Engineer Fee Proposal) Activity; Comment Request

Science.gov (United States)

2011-11-15

... DEPARTMENT OF VETERANS AFFAIRS [OMB Control No. 2900-0208] Proposed Information Collection (Architect--Engineer Fee Proposal) Activity; Comment Request AGENCY: Veterans Health Administration.... Architect--Engineer Fee Proposal, VA Form 10-6298. b. Daily Log (Contract Progress Report--Formal Contract...

Intelligent Power Control of DC Microgrid

DEFF Research Database (Denmark)

Hajizadeh, Amin; N. Soltani, Mohsen; Norum, Lars

2017-01-01

In this paper, an intelligent power management strategy is proposed for hybrid DC microgrid, including wind turbine, fuel cell and battery energy storage. The considered wind turbine has a permanent magnet synchronous generator (PMSG). In the considered structure, wind turbine operates as the main...... condition and fuel cell will not generate excessive power. The proposed control scheme is based on the fuzzy algorithm. All simulations in variant operational modes are performed by MATLAB/Simulink and results show the effectiveness of the proposed control strategy....

Adaptive Sliding Mode Robust Control for Virtual Compound-Axis Servo System

Directory of Open Access Journals (Sweden)

Yan Ren

2013-01-01

Full Text Available A structure mode of virtual compound-axis servo system is proposed to improve the tracking accuracy of the ordinary optoelectric tracking platform. It is based on the structure and principles of compound-axis servo system. A hybrid position control scheme combining the PD controller and feed-forward controller is used in subsystem to track the tracking error of the main system. This paper analyzes the influences of the equivalent disturbance in main system and proposes an adaptive sliding mode robust control method based on the improved disturbance observer. The sliding mode technique helps this disturbance observer to deal with the uncompensated disturbance in high frequency by making use of the rapid switching control value, which is based on the subtle error of disturbance estimation. Besides, the high-frequency chattering is alleviated effectively in this proposal. The effectiveness of the proposal is confirmed by experiments on optoelectric tracking platform.

Describing qualitative research undertaken with randomised controlled trials in grant proposals: a documentary analysis

Science.gov (United States)

2014-01-01

Background There is growing recognition of the value of conducting qualitative research with trials in health research. It is timely to reflect on how this qualitative research is presented in grant proposals to identify lessons for researchers and research commissioners. As part of a larger study focusing on how to maximise the value of undertaking qualitative research with trials, we undertook a documentary analysis of proposals of funded studies. Methods Using the metaRegister of Controlled Trials (mRCT) database we identified trials funded in the United Kingdom, ongoing between 2001 and 2010, and reporting the use of qualitative research. We requested copies of proposals from lead researchers. We extracted data from the proposals using closed and open questions, analysed using descriptive statistics and content analysis respectively. Results 2% (89/3812) of trials in the mRCT database described the use of qualitative research undertaken with the trial. From these 89 trials, we received copies of 36 full proposals, of which 32 met our inclusion criteria. 25% used less than a single paragraph to describe the qualitative research. The aims of the qualitative research described in these proposals focused mainly on the intervention or trial conduct. Just over half (56%) of the proposals included an explicit rationale for conducting the qualitative research with the trial, the most frequent being to optimise implementation into clinical practice or to interpret trial findings. Key information about methods, expertise and resources was missing in a large minority of proposals, in particular sample size, type of analysis, and non-personnel resources. 28% specifically stated that qualitative researchers would conduct the qualitative research. Conclusions Our review of proposals of successfully funded studies identified good practice but also identified limited space given to describing the qualitative research, with an associated lack of attention to the rationale for

Predicting health-related quality of life in cancer patients receiving chemotherapy: a structural equation approach using the self-control model.

Science.gov (United States)

Park, Yu-Ri; Park, Eun-Young; Kim, Jung-Hee

2017-11-09

According to the self-control model, self-control works as a protective factor and a psychological resource. Although an understanding of the effect(s) of peripheral neuropathy on quality of life is important to healthcare professionals, previous studies do not facilitate broad comprehension in this regard. The purpose of this cross-sectional study was to test the multidimensional assumptions of quality of life of patients with cancer, with focus on their self-control. A structural equation model was tested on patients with cancer at the oncology clinic of a university hospital where patients received chemotherapy. A model was tested using structural equation modeling, which allows the researcher to find the empirical evidence by testing a measurement model and a structural model. The model comprised three variables, self-control, health related quality of life, and chemotherapy-induced peripheral neuropathy. Among the variables, self-control was the endogenous and mediating variable. The proposed models showed good fit indices. Self-control partially mediated chemotherapy-induced peripheral neuropathy and quality of life. It was found that the physical symptoms of peripheral neuropathy influenced health-related quality of life both indirectly and directly. Self-control plays a significant role in the protection and promotion of physical and mental health in various stressful situations, and thus, as a psychological resource, it plays a significant role in quality of life. Our results can be used to develop a quality of life model for patients receiving chemotherapy and as a theoretical foundation for the development of appropriate nursing interventions.

A GPS-Based Control Method for Load Sharing and Power Quality Improvement in Microgrids

DEFF Research Database (Denmark)

Golsorkhi, Mohammad; Lu, Dylan; Savaghebi, Mehdi

2016-01-01

This paper proposes a novel control method for accurate sharing of load current among the Distributed Energy Resources (DER) and high power quality operating in islanded ac microgrids. This control scheme is based on hierarchical structure comprising of decentralized primary controllers and a cen....... The secondary controller produces compensation signals at fundamental and dominant harmonics to improve the voltage quality at a sensitive load bus. Experimental results are presented to validate the efficacy of the proposed method.......This paper proposes a novel control method for accurate sharing of load current among the Distributed Energy Resources (DER) and high power quality operating in islanded ac microgrids. This control scheme is based on hierarchical structure comprising of decentralized primary controllers...

Proposal for Certifying Expandable Planetary Surface Habitation Structures

Science.gov (United States)

Dorsey, John T.

2011-01-01

A factor-of-safety (FS) of 4.0 is currently used to design habitation structures made from structural soft goods. This approach is inconsistent with using a FS of 2.0 for metallic and polymeric composite pressure vessels as well as soft good structures such as space suits and parachutes. This inconsistency arises by using the FS to improperly account for the unknown effects of a variety of environmental and loading uncertainties. Using a 4.0 FS not only results in additional structural mass, it also makes it difficult to gain insight into the limitations of the material and/or product form and thus, it becomes difficult to make improvements. In order to bring consistency to the design and certification of expandable habitat structures, the approach used by the Federal Aviation Administration (FAA) to certify polymeric composite aircraft structures is used as a model and point of departure. A draft certification plan for Expandable Habitat Structures is developed in this paper and offered as an option for placing habitats made from soft goods on an equal footing with other structural implementations.

Quality control of structural MRI images applied using FreeSurfer - a hands-on workflow to rate motion artifacts

Directory of Open Access Journals (Sweden)

Lea Luise Backhausen

2016-12-01

Full Text Available In structural magnetic resonance imaging motion artifacts are common, especially when not scanning healthy young adults. It has been shown that motion affects the analysis with automated image-processing techniques (e.g. FreeSurfer. This can bias results. Several developmental and adult studies have found reduced volume and thickness of gray matter due to motion artifacts. Thus, quality control is necessary in order to ensure an acceptable level of quality and to define exclusion criteria of images (i.e. determine participants with most severe artifacts. However, information about the quality control workflow and image exclusion procedure is largely lacking in the current literature and the existing rating systems differ. Here we propose a stringent workflow of quality control steps during and after acquisition of T1-weighted images, which enables researchers dealing with populations that are typically affected by motion artifacts to enhance data quality and maximize sample sizes. As an underlying aim we established a thorough quality control rating system for T1-weighted images and applied it to the analysis of developmental clinical data using the automated processing pipeline FreeSurfer. This hands-on workflow and quality control rating system will aid researchers in minimizing motion artifacts in the final data set, and therefore enhance the quality of structural magnetic resonance imaging studies.

Hybrid Control of Supply Chains: a Structured Exploration from a Systems Perspective

Directory of Open Access Journals (Sweden)

Paul W. P. J. Grefen

2013-07-01

Full Text Available Supply chains are becoming increasingly complex these days, both in the structure of the chains and in the need for fine-grained, real-time control. This development occurs in many industries, such as manufacturing, logistics, and the service industry. The increasing structural complexity is caused by larger numbers of participating companies in supply chains because of increasing complexity of products and services. Increasing requirements to control are caused by developments like mass-customization, pressure on delivery times, and smaller margins for waste. Maintaining well-structured strategic, tactic, and operational control over these complex supply chains is not an easy task – certainly as they are pressured by end-to-end synchronization requirements and just-in-time demands. Things become even more complex when chains need to be flexible to react to changing requirements to the products or services they deliver. To enable design of well-structured control, clear models of control topologies are required. In this paper, we address this need by exploring supply chain control topologies in an organized fashion. The exploration is based on integrating a supply chain model and a control model in two alternative ways to obtain two extreme models for supply chain control. These two models are next combined to obtain a hybrid chain control model in which control parameters can be adapted to accommodate different circumstances, hence facilitating agility in supply chains and networks. We apply the developed model to a number of case studies to show its usability. The contribution of this paper is the structured analysis of the design space for chain-level control models - not the description of individual new models.

Challenges of Control in Functional Organization Structures: Example of Outsourcing Sector

OpenAIRE

Agnieszka Maciejczyk

2016-01-01

Effective control of an organization is strictly connected with its organization structure. When a company decides to outsource a part of its operations, a new structure is applied. Also, the system of control should be reviewed and adjusted to the new model of business in order to be effective. Usually, the outsourcing companies apply functional organization structure which is the most common way of grouping business activities. The goal of the paper was to point challenges and aspects which...

Structural control of the basement in the central portion of the Santos Basin-Brazil; Controle estrutural do embasamento na porcao central da Bacia de Santos

Energy Technology Data Exchange (ETDEWEB)

Izeli, Maira G.B.; Morales, Norberto; Souza, Iata A. de [Universidade Estadual Paulista (UNESP), Rio Claro, SP (Brazil). Inst. de Geociencias e Ciencias Exatas

2008-07-01

New discoveries of oil in deep water and ultra-deep water in Santos Basin suggest that it needs to be studied to better understanding of basement structures and their role in the basin control and configuration. This study characterizes the main tectonic structures of a portion at the central area of this basin, looking for their relation to the geological basement framework. The study is based on the integration of the geological and geophysical data from subsurface (offshore) and surface of the adjacent continent. These analyses include the continental structures that continue in direction of this basin (Guapiara Lineament and Ponta Grossa Arc), checking their possible influence on the basin evolution and deformation. To achieve the proposed goals, the Precambrian basement lineaments were extracted from the offshore area using remote sensing, as result was obtained strong NW-SE structural trend. According to the interpretation of seismic sections, it is possible to observe that this portion of the basin presents main NE-SW structural trend, and most of the structures are typical of passive margin and halokintics process. It is possible to see that some recognized faults in the rift deposits may be coinciding with the main continental guidelines which are projected into the basin. (author)

Perceptual organization in computer vision - A review and a proposal for a classificatory structure

Science.gov (United States)

Sarkar, Sudeep; Boyer, Kim L.

1993-01-01

The evolution of perceptual organization in biological vision, and its necessity in advanced computer vision systems, arises from the characteristic that perception, the extraction of meaning from sensory input, is an intelligent process. This is particularly so for high order organisms and, analogically, for more sophisticated computational models. The role of perceptual organization in computer vision systems is explored. This is done from four vantage points. First, a brief history of perceptual organization research in both humans and computer vision is offered. Next, a classificatory structure in which to cast perceptual organization research to clarify both the nomenclature and the relationships among the many contributions is proposed. Thirdly, the perceptual organization work in computer vision in the context of this classificatory structure is reviewed. Finally, the array of computational techniques applied to perceptual organization problems in computer vision is surveyed.

A novel multi-drive electric vehicle system control based on multi-input multi-output PID controller

Directory of Open Access Journals (Sweden)

Gasbaoui Brahim

2012-01-01

Full Text Available In-wheel-motor drive electric vehicle (EV is an innovative configuration of the modern EV, in which each wheel is driven individually by an electric motor. The classical traction motor control called the Independent Machine Control Structure (IMCS using a PID speed controller presents major inconveniences in modern EV safety, when the proposed control can not ensure stability of the EV with differing road topology and variations of speed. A new approach is proposed for a control of a two-in-wheel-motor drive EV, called the Maximum Control Structure MCS. This is based on a multivariable PID (MIMO-PID strategy, which is employed to estimate the linear speed error of each of the two back driving wheels, when the error of each wheel is taken into account in the other speed control computations. Simulation results show that the new control system presents increased safety for the EVs compared with the IMCS strategy and can maintain the error slip rate within the optimal range, ensuring the stability of the vehicle either in a straight or a curved line.

Decoupling structure and metallogenesis

International Nuclear Information System (INIS)

Tong Hangshou

1993-01-01

The decoupling structure is, at present, a hot spot for the study in geoscience. A study on the decoupling structure is not only of great theoretical significance, but also of more economic importance. The author briefly discusses the study of the decoupling structure in terms of its present status, implication, characteristics, formation mechanism and theoretical significance, in addition, with emphasis on the expounding of the decoupling structure over endogenic metallic deposits such as oil and gas, coal, gold, silver, copper, lead, zinc and iron etc. At last reconsideration is made on the ore control theory of the decoupling structure to the ore control structure in the uranium ore field in South China. The author proposes a superficial idea in order to provide a basis of geological structures for expanding old mining areas, opening up new areas(bases), and prospecting for large and rich uranium deposits

Control and diagnostic data structures for the MFTF

International Nuclear Information System (INIS)

Wade, J.A.; Choy, J.H.

1979-01-01

A Data Base Management System (DBMS) is being written as an integral part of the Supervisory Control and Diagnostics System (SCDS) of programs for control of the Mirror Fusion Test Facility (MFTF). The data upon which the DBMS operates consist of control values and evaluative information required for facilities control, along with control values and disgnostic data acquired as a result of each MFTF shot. The user interface to the DBMS essentially consists of two views: a computer program interface called the Program Level Interface (PLI) and a stand-alone interactive program called the Query Level Interface to support terminal-based queries. This paper deals specifically with the data structure capabilities from the viewpoint of the PLI user

Speed control of permanent magnet excitation transverse flux linear motor by using adaptive neuro-fuzzy controller

Energy Technology Data Exchange (ETDEWEB)

Hasanien, Hany M., E-mail: Hanyhasanien@ieee.or [Dept. of Elec. Power and Machines, Faculty of Eng., Ain-shams Univ. Cairo (Egypt); Muyeen, S.M. [Department of Electrical Engineering, Petroleum Institute, Abu Dhabi (United Arab Emirates); Tamura, Junji [Department of EEE, Kitami Institute of Technology, 165 Koen Cho, Kitami 090-8507, Hokkaido (Japan)

2010-12-15

This paper presents a novel adaptive neuro-fuzzy controller applies on transverse flux linear motor for controlling its speed. The proposed controller presents fuzzy logic controller with self tuning scaling factors based on artificial neural network structure. It has two input variables and one control output variable. Firstly the fuzzy logic control rules are described then NN architecture is represented to self tune the output scaling factors of the controller. The application of this control technique represents the novelty of work, where this algorithm has so far not been stated before for this type of drives. This methodology solves the problem of nonlinearities and load changes of TFLM drives. The dynamic response of the motor is studied under the rated load condition as well as load disturbances. The proposed controller ensures fast and accurate dynamic response with an excellent steady state performance. The dynamic response of the motor with the proposed controller is compared with PI and adaptive NN controllers. It is found that the proposed controller gives better and faster response from the viewpoint of overshoot and settling time. Matlab/Simulink tool is used for this dynamic simulation study.

Robust wide-range control of nuclear reactors by using the feedforward-feedback concept

International Nuclear Information System (INIS)

Weng, C.K.; Edwards, R.M.; Ray, A.

1994-01-01

A robust feedforward-feedback controller is proposed for wide-range operations of nuclear reactors. This control structure provides (a) optimized performance over a wide operating range resulting form the feedforward element and (b) guaranteed robust stability and performance resulting from the feedback element. The feedforward control law is synthesized via nonlinear programming, which generates an optimal control sequence over a finite-time horizon under specified constraints. The feedback control is synthesized via the structured singular value μ approach to guarantee robustness in the presence of disturbances and modeling uncertainties. The results of simulation experiments are presented to demonstrate efficacy of the proposed control structure for a large rapid power reduction to avoid unnecessary plant trips

Active Structural Acoustic Control in an Original A400M Aircraft Structure

International Nuclear Information System (INIS)

Koehne, C; Sachau, D; Renger, K

2016-01-01

Low frequency noise has always been a challenge in propeller driven aircraft. At low frequencies passive noise treatments are not as efficient as active noise reduction systems. The Helmut-Schmidt-University has built up a full-scale test rig with an original A400M aircraft structure. This provides a good opportunity to develop and test active noise reduction systems in a realistic environment. The currently installed system consists of mechanical actuators and acoustical sensors. The actuators are called TVAs (Tuneable Vibration Absorber) and contain two spring-mass systems whose natural frequencies are adjusted to the BPFs (Blade Passage Frequency) of the propellers. The TVAs are mounted to the frames and the force direction is normal to the skin. The sensors are condenser microphones which are attached to the primary structure of the airframe. The TVAs are equipped with signal processing devices. These components carry out Fourier transforms and signal amplification for the sensor data and actuator signals. The communication between the TVAs and the central control unit is implemented by the CAN Bus protocol and mainly consists of complex coefficients for the sensor and actuator data. This paper describes the basic structure of the system, the hardware set-up and function tests of the controller. (paper)

Active Structural Acoustic Control in an Original A400M Aircraft Structure

Science.gov (United States)

Koehne, C.; Sachau, D.; Renger, K.

2016-09-01

Low frequency noise has always been a challenge in propeller driven aircraft. At low frequencies passive noise treatments are not as efficient as active noise reduction systems. The Helmut-Schmidt-University has built up a full-scale test rig with an original A400M aircraft structure. This provides a good opportunity to develop and test active noise reduction systems in a realistic environment. The currently installed system consists of mechanical actuators and acoustical sensors. The actuators are called TVAs (Tuneable Vibration Absorber) and contain two spring-mass systems whose natural frequencies are adjusted to the BPFs (Blade Passage Frequency) of the propellers. The TVAs are mounted to the frames and the force direction is normal to the skin. The sensors are condenser microphones which are attached to the primary structure of the airframe. The TVAs are equipped with signal processing devices. These components carry out Fourier transforms and signal amplification for the sensor data and actuator signals. The communication between the TVAs and the central control unit is implemented by the CAN Bus protocol and mainly consists of complex coefficients for the sensor and actuator data. This paper describes the basic structure of the system, the hardware set-up and function tests of the controller.

Control-group feature normalization for multivariate pattern analysis of structural MRI data using the support vector machine.

Science.gov (United States)

Linn, Kristin A; Gaonkar, Bilwaj; Satterthwaite, Theodore D; Doshi, Jimit; Davatzikos, Christos; Shinohara, Russell T

2016-05-15

Normalization of feature vector values is a common practice in machine learning. Generally, each feature value is standardized to the unit hypercube or by normalizing to zero mean and unit variance. Classification decisions based on support vector machines (SVMs) or by other methods are sensitive to the specific normalization used on the features. In the context of multivariate pattern analysis using neuroimaging data, standardization effectively up- and down-weights features based on their individual variability. Since the standard approach uses the entire data set to guide the normalization, it utilizes the total variability of these features. This total variation is inevitably dependent on the amount of marginal separation between groups. Thus, such a normalization may attenuate the separability of the data in high dimensional space. In this work we propose an alternate approach that uses an estimate of the control-group standard deviation to normalize features before training. We study our proposed approach in the context of group classification using structural MRI data. We show that control-based normalization leads to better reproducibility of estimated multivariate disease patterns and improves the classifier performance in many cases. Copyright © 2016 Elsevier Inc. All rights reserved.

Neural networkbased semi-active control strategy for structural vibration mitigation with magnetorheological damper

DEFF Research Database (Denmark)

Bhowmik, Subrata

2011-01-01

This paper presents a neural network based semi-active control method for a rotary type magnetorheological (MR) damper. The characteristics of the MR damper are described by the classic Bouc-Wen model, and the performance of the proposed control method is evaluated in terms of a base exited shear...... to determine the damper current based on the derived optimal damper force. For that reason an inverse MR damper model is also designed based on the neural network identification of the particular rotary MR damper. The performance of the proposed controller is compared to that of an optimal pure viscous damper...

Accuracy Enhanced Stability and Structure Preserving Model Reduction Technique for Dynamical Systems with Second Order Structure

DEFF Research Database (Denmark)

Tahavori, Maryamsadat; Shaker, Hamid Reza

A method for model reduction of dynamical systems with the second order structure is proposed in this paper. The proposed technique preserves the second order structure of the system, and also preserves the stability of the original systems. The method uses the controllability and observability...... gramians within the time interval to build the appropriate Petrov-Galerkin projection for dynamical systems within the time interval of interest. The bound on approximation error is also derived. The numerical results are compared with the counterparts from other techniques. The results confirm...

Generalization of proposed tendon friction correlation and its application to PCCV structural analysis

International Nuclear Information System (INIS)

Kashiwase, Takako; Nagasaka, Hideo

2000-01-01

The present paper dealt with the extension of tendon friction coefficient correlation as a function of loading end load and circumferential angle, proposed in the former paper. The extended correlation further included the effects of the number of strands contacted with sheath, tendon diameter, politicization of tendon and tendon local curvature. The validity of the correlation was confirmed by several published measured data. The structural analysis of middle cylinder part of 1/4 PCCV (Prestressed Concrete Containment Vessel) model was conducted using the present friction coefficient correlation. The results were compared with the analysis using constant friction coefficient, focused on the tendon tension force distribution. (author)

Didactic System for the Experimental Study of Digital PID Control Structures

Directory of Open Access Journals (Sweden)

Stelian-Emilian OLTEAN

2016-12-01

Full Text Available The proportional integral derivative (PID controller has a known structure used in feedback control of industrial processes. One of the most common applications is the control of the DC motor. The paper presents a didactic system designed for educational purposes used for studying various conventional PID structures and the influence of the PID components in the control process of the DC motor’s speed. The system contains a low cost acquisition board based on PIC 16F628A microcontroller. The experimental results are shown graphically using a PC application made in Matlab environment.