WorldWideScience

Sample records for digital control schemes

  1. Digital simulation and hardware implementation of a simple scheme for direct torque control of induction motor

    International Nuclear Information System (INIS)

    Prasad, Dinkar; Panigrahi, Bibhu Prasad; SenGupta, Sabyasachi

    2008-01-01

    A simple scheme that allows fast control of induction motor torque has been presented. It is different from the conventional direct torque control (DTC) scheme in the sense that it does not use the popular DTC switching table. Also, it does not require use of any online fast computing device like a microprocessor, personal computer (PC) or digital signal processor (DSP). The proposed scheme uses only commonly used discrete hardware components for its implementation. The experimental results obtained from the hardware realization of the proposed scheme are found to be in close agreement with the simulation results

  2. Demand Controlled Economizer Cycles: A Direct Digital Control Scheme for Heating, Ventilating, and Air Conditioning Systems,

    Science.gov (United States)

    1984-05-01

    includes a heating coil and thermostatic control to maintain the air in this path at an elevated temperature, typically around 80 degrees Farenheit (80 F...1238 Aug 1 1236 1237 52 1074 1126 50 1033 1083 Sep 8 8 5W 862 7T 600 678 75 603 7r Oct 51 400 451 119 204 323 115 207 322 ov 64 123 287 187 71 258

  3. Scheme of stepmotor control

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Karyshev, Yu.Ya.

    1982-01-01

    A 6-cycle scheme of step motor is described. The block-diagram and the basic circuit of the step motor control are presented. The step motor control comprises a pulse shaper, electronic commutator and power amplifiers. The step motor supply from 6-cycle electronic commutator provides for higher reliability and accuracy than from 3-cycle commutator. The control of step motor work is realised by the program given by the external source of control signals. Time-dependent diagrams for step motor control are presented. The specifications of the step-motor is given

  4. Forgery attack to Kang-Tang digital signature scheme

    Science.gov (United States)

    Fang, Jie; Guo, Yongning; Liu, Chenglian

    2014-10-01

    In 2006, Kang and Tang proposed a digital signature scheme without hash functions and message redundancy. They claimed their scheme are more efficient in computation and communication for small device. In this paper, we will point out an new attack to certain the Kang-Tang scheme is insecure.

  5. An intelligent robotics control scheme

    Science.gov (United States)

    Orlando, N. E.

    1984-01-01

    The problem of robot control is viewed at the level of communicating high-level commands produced by intelligent algorithms to the actuator/sensor controllers. Four topics are considered in the design of an integrated control and communications scheme for an intelligent robotic system: the use of abstraction spaces, hierarchical versus heterarchical control, distributed processing, and the interleaving of the steps of plan creation and plan execution. A scheme is presented for an n-level distributed hierarchical/heterarchical control system that effectively interleaves intelligent planning, execution, and sensory feedback. A three-level version of this scheme has been successfully implemented in the Intelligent Systems Research Lab at NASA Langley Research Center. This implementation forms the control structure for DAISIE (Distributed Artificially Intelligent System for Interacting with the Environment), a testbed system integrating AI software with robotics hardware.

  6. Efficient adaptive fuzzy control scheme

    NARCIS (Netherlands)

    Papp, Z.; Driessen, B.J.F.

    1995-01-01

    The paper presents an adaptive nonlinear (state-) feedback control structure, where the nonlinearities are implemented as smooth fuzzy mappings defined as rule sets. The fine tuning and adaption of the controller is realized by an indirect adaptive scheme, which modifies the parameters of the fuzzy

  7. A Digital Signature Scheme Based on MST3 Cryptosystems

    Directory of Open Access Journals (Sweden)

    Haibo Hong

    2014-01-01

    Full Text Available As special types of factorization of finite groups, logarithmic signature and cover have been used as the main components of cryptographic keys for secret key cryptosystems such as PGM and public key cryptosystems like MST1, MST2, and MST3. Recently, Svaba et. al proposed a revised MST3 encryption scheme with greater security. Meanwhile, they put forward an idea of constructing signature schemes on the basis of logarithmic signatures and random covers. In this paper, we firstly design a secure digital signature scheme based on logarithmic signatures and random covers. In order to complete the task, we devise a new encryption scheme based on MST3 cryptosystems.

  8. A digital memories based user authentication scheme with privacy preservation.

    Science.gov (United States)

    Liu, JunLiang; Lyu, Qiuyun; Wang, Qiuhua; Yu, Xiangxiang

    2017-01-01

    The traditional username/password or PIN based authentication scheme, which still remains the most popular form of authentication, has been proved insecure, unmemorable and vulnerable to guessing, dictionary attack, key-logger, shoulder-surfing and social engineering. Based on this, a large number of new alternative methods have recently been proposed. However, most of them rely on users being able to accurately recall complex and unmemorable information or using extra hardware (such as a USB Key), which makes authentication more difficult and confusing. In this paper, we propose a Digital Memories based user authentication scheme adopting homomorphic encryption and a public key encryption design which can protect users' privacy effectively, prevent tracking and provide multi-level security in an Internet & IoT environment. Also, we prove the superior reliability and security of our scheme compared to other schemes and present a performance analysis and promising evaluation results.

  9. A digital memories based user authentication scheme with privacy preservation.

    Directory of Open Access Journals (Sweden)

    JunLiang Liu

    Full Text Available The traditional username/password or PIN based authentication scheme, which still remains the most popular form of authentication, has been proved insecure, unmemorable and vulnerable to guessing, dictionary attack, key-logger, shoulder-surfing and social engineering. Based on this, a large number of new alternative methods have recently been proposed. However, most of them rely on users being able to accurately recall complex and unmemorable information or using extra hardware (such as a USB Key, which makes authentication more difficult and confusing. In this paper, we propose a Digital Memories based user authentication scheme adopting homomorphic encryption and a public key encryption design which can protect users' privacy effectively, prevent tracking and provide multi-level security in an Internet & IoT environment. Also, we prove the superior reliability and security of our scheme compared to other schemes and present a performance analysis and promising evaluation results.

  10. Integrated optical 3D digital imaging based on DSP scheme

    Science.gov (United States)

    Wang, Xiaodong; Peng, Xiang; Gao, Bruce Z.

    2008-03-01

    We present a scheme of integrated optical 3-D digital imaging (IO3DI) based on digital signal processor (DSP), which can acquire range images independently without PC support. This scheme is based on a parallel hardware structure with aid of DSP and field programmable gate array (FPGA) to realize 3-D imaging. In this integrated scheme of 3-D imaging, the phase measurement profilometry is adopted. To realize the pipeline processing of the fringe projection, image acquisition and fringe pattern analysis, we present a multi-threads application program that is developed under the environment of DSP/BIOS RTOS (real-time operating system). Since RTOS provides a preemptive kernel and powerful configuration tool, with which we are able to achieve a real-time scheduling and synchronization. To accelerate automatic fringe analysis and phase unwrapping, we make use of the technique of software optimization. The proposed scheme can reach a performance of 39.5 f/s (frames per second), so it may well fit into real-time fringe-pattern analysis and can implement fast 3-D imaging. Experiment results are also presented to show the validity of proposed scheme.

  11. Programmable Digital Controller

    Science.gov (United States)

    Wassick, Gregory J.

    2012-01-01

    An existing three-channel analog servo loop controller has been redesigned for piezoelectric-transducer-based (PZT-based) etalon control applications to a digital servo loop controller. This change offers several improvements over the previous analog controller, including software control over proportional-integral-derivative (PID) parameters, inclusion of other data of interest such as temperature and pressure in the control laws, improved ability to compensate for PZT hysteresis and mechanical mount fluctuations, ability to provide pre-programmed scanning and stepping routines, improved user interface, expanded data acquisition, and reduced size, weight, and power.

  12. Adaptive nonseparable vector lifting scheme for digital holographic data compression.

    Science.gov (United States)

    Xing, Yafei; Kaaniche, Mounir; Pesquet-Popescu, Béatrice; Dufaux, Frédéric

    2015-01-01

    Holographic data play a crucial role in recent three-dimensional imaging as well as microscopic applications. As a result, huge amounts of storage capacity will be involved for this kind of data. Therefore, it becomes necessary to develop efficient hologram compression schemes for storage and transmission purposes. In this paper, we focus on the shifted distance information, obtained by the phase-shifting algorithm, where two sets of difference data need to be encoded. More precisely, a nonseparable vector lifting scheme is investigated in order to exploit the two-dimensional characteristics of the holographic contents. Simulations performed on different digital holograms have shown the effectiveness of the proposed method in terms of bitrate saving and quality of object reconstruction.

  13. Cross-cutting categorization schemes in the digital humanities.

    Science.gov (United States)

    Allen, Colin

    2013-09-01

    Digital access to large amounts of scholarly text presents both challenges and opportunities for researchers in the humanities. Meeting these challenges depends on having high-quality representations of the contents of digital resources suitable for both machines and humans to use. Different ways of categorizing these contents are appropriate for different purposes, leading to the further problem of relating the contents of different categorization schemes to each other. This essay discusses the rationale for categorizing philosophical concepts and surveys some of the main approaches to doing so for materials that are continuously changing. It describes the goals and methods of the Indiana Philosophy Ontology (InPhO) project and provides an example of the kind of analysis that is made possible by powerful modeling methods.

  14. On the security of pairing-free certificateless digital signature schemes using ECC

    Directory of Open Access Journals (Sweden)

    Namita Tiwari

    2015-09-01

    Full Text Available I cryptanalyze the pairing-free digital signature scheme of Islam et al. which is proven secure against “adaptive chosen message attacks”. I introduce this type of forgery to analyze their scheme. Furthermore, I comment on general security issues that should be considered when making improvements on their scheme. My security analysis is also applicable to other digital signatures designed in a similar manner.

  15. On the Security of Digital Signature Schemes Based on Error-Correcting Codes

    NARCIS (Netherlands)

    Xu, Sheng-bo; Doumen, J.M.; van Tilborg, Henk

    We discuss the security of digital signature schemes based on error-correcting codes. Several attacks to the Xinmei scheme are surveyed, and some reasons given to explain why the Xinmei scheme failed, such as the linearity of the signature and the redundancy of public keys. Another weakness is found

  16. Control theory of digitally networked dynamic systems

    CERN Document Server

    Lunze, Jan

    2013-01-01

    The book gives an introduction to networked control systems and describes new modeling paradigms, analysis methods for event-driven, digitally networked systems, and design methods for distributed estimation and control. Networked model predictive control is developed as a means to tolerate time delays and packet loss brought about by the communication network. In event-based control the traditional periodic sampling is replaced by state-dependent triggering schemes. Novel methods for multi-agent systems ensure complete or clustered synchrony of agents with identical or with individual dynamic

  17. Analysis and design of digital output interface devices for gas turbine electronic controls

    Science.gov (United States)

    Newirth, D. M.; Koenig, E. W.

    1976-01-01

    A trade study was performed on twenty-one digital output interface schemes for gas turbine electronic controls to select the most promising scheme based on criteria of reliability, performance, cost, and sampling requirements. The most promising scheme, a digital effector with optical feedback of the fuel metering valve position, was designed.

  18. A Non-symmetric Digital Image Secure Communication Scheme Based on Generalized Chaos Synchronization System

    International Nuclear Information System (INIS)

    Zhang Xiaohong; Min Lequan

    2005-01-01

    Based on a generalized chaos synchronization system and a discrete Sinai map, a non-symmetric true color (RGB) digital image secure communication scheme is proposed. The scheme first changes an ordinary RGB digital image with 8 bits into unrecognizable disorder codes and then transforms the disorder codes into an RGB digital image with 16 bits for transmitting. A receiver uses a non-symmetric key to verify the authentication of the received data origin, and decrypts the ciphertext. The scheme can encrypt and decrypt most formatted digital RGB images recognized by computers, and recover the plaintext almost without any errors. The scheme is suitable to be applied in network image communications. The analysis of the key space, sensitivity of key parameters, and correlation of encrypted images imply that this scheme has sound security.

  19. Block-classified motion compensation scheme for digital video

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, S. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.; Zhang, Ya-Qin [David Sarnoff Research Center, Princeton, NJ (United States); Jabbari, B. [George Mason Univ., Fairfax, VA (United States). Dept. of Electrical and Computer Engineering

    1996-03-01

    A novel scheme for block-based motion compensation is introduced in which a block is classified according to the energy that is directly related to the motion activity it represents. This classification allows more flexibility in controlling the bit rate arid the signal-to-noise ratio and results in a reduction in motion search complexity. The method introduced is not dependent on the particular type of motion search algorithm implemented and can thus be used with any method assuming that the underlying matching criteria used is minimum absolute difference. It has been shown that the method is superior to a simple motion compensation algorithm where all blocks are motion compensated regardless of the energy resulting after the displaced difference.

  20. Digital control for turbogas units; Control digital para unidades turbogas

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Beltran, Carlos Daniel

    1997-02-01

    implementation and testing of several schemes of diffuse control: P, PD, PI and diffuse PID, of which the last one was selected for having a better answer. The results obtained in the simulations of the algebraic PI and of the diffuse PID, established that the second one improved the follow up indexes and reduced the starting period and the fuel consumption. [Espanol] La presente tesis trata sobre la rehabilitacion del sistema de control para las turbinas de gas W501 de la Central de Ciclo Combinado de Gomez Palacio, de Durango, Mexico. La primera parte del desarrollo trata sobre un proceso de reingenieria de software aplicado al sistema de control digital de las turbinas de gas de la central de ciclo combinado de Comez Palacio. Este proceso fue desarrollado utilizando conceptos de varias ramas de la ingenieria: a) involucro los conocimientos de la ingenieria de software, utilizando metodos formales para el analisis del sistema original y el rediseno del nuevo sistema: b) se utilizo la ingenieria de control en el analisis de diversas estrategias de control y automatizacion utilizados para el control de turbinas de gas, con el objetivo de verificar el tipo de instrucciones y rutinas presentes dentro del software. El producto final de esta etapa es un sistema programatico modularizado, basado en diseno estructurado, que es funcionalmente un espejo del sistema original. El sistema obtenido esta conformado por cinco modulos principales los cuales se basan en un modelo propuesto originalmente para control por lotes (batch) :i) Interfaz Hombre Maquina, ii) Control Regulatorio, iii) Protecciones, iv) Secuencias logicas y v) Supervision. La segunda etapa de desarrollo fue la mejora del control de velocidad de la turbina. Cuando se controla una unidad turbogas, debe tomarse en cuenta varias etapas de operacion tales como el arranque, el control en estado estable y el apagado. El comportamiento real de la turbina durante el arranque, y principalmente el gran numero de retrocesos

  1. Digitally controlled distributed phase shifter

    Science.gov (United States)

    Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

    1993-01-01

    A digitally controlled distributed phase shifter is comprised of N phase shifters. Digital control is achieved by using N binary length-weighted electrodes located on the top surface of a waveguide. A control terminal is attached to each electrode thereby allowing the application of a control signal. The control signal is either one or two discrete bias voltages. The application of the discrete bias voltages changes the modal index of a portion of the waveguide that corresponds to a length of the electrode to which the bias voltage is applied, thereby causing the phase to change through the underlying portion of the waveguide. The digitally controlled distributed phase shift network has a total phase shift comprised of the sum of the individual phase shifters.

  2. A Privacy-Preserving Outsourcing Data Storage Scheme with Fragile Digital Watermarking-Based Data Auditing

    Directory of Open Access Journals (Sweden)

    Xinyue Cao

    2016-01-01

    Full Text Available Cloud storage has been recognized as the popular solution to solve the problems of the rising storage costs of IT enterprises for users. However, outsourcing data to the cloud service providers (CSPs may leak some sensitive privacy information, as the data is out of user’s control. So how to ensure the integrity and privacy of outsourced data has become a big challenge. Encryption and data auditing provide a solution toward the challenge. In this paper, we propose a privacy-preserving and auditing-supporting outsourcing data storage scheme by using encryption and digital watermarking. Logistic map-based chaotic cryptography algorithm is used to preserve the privacy of outsourcing data, which has a fast operation speed and a good effect of encryption. Local histogram shifting digital watermark algorithm is used to protect the data integrity which has high payload and makes the original image restored losslessly if the data is verified to be integrated. Experiments show that our scheme is secure and feasible.

  3. Digital control in power electronics

    CERN Document Server

    Buso, Simone

    2015-01-01

    This book presents the reader, whether an electrical engineering student in power electronics or a design engineer, a selection of power converter control problems and their basic digital solutions, based on the most widespread digital control techniques. The presentation is primarily focused on different applications of the same power converter topology, the half-bridge voltage source inverter, considered both in its single- and three-phase implementation. This is chosen as the test case because, besides being simple and well known, it allows the discussion of a significant spectrum of the mo

  4. Digital control in power electronics

    CERN Document Server

    Buso, Simone

    2006-01-01

    This book presents the reader, whether an electrical engineering student in power electronics or a design engineer, some typical power converter control problems and their basic digital solutions, based on the most widespread digital control techniques. The presentation is focused on different applications of the same power converter topology, the half-bridge voltage source inverter, considered both in its single- and three-phase implementation. This is chosen as the case study because, besides being simple and well known, it allows the discussion of a significant spectrum of the more frequent

  5. A scheme for recording a fast process at nanosecond scale by using digital holographic interferometry with continuous wave laser

    Science.gov (United States)

    Wang, Jun; Zhao, Jianlin; Di, Jianglei; Jiang, Biqiang

    2015-04-01

    A scheme for recording fast process at nanosecond scale by using digital holographic interferometry with continuous wave (CW) laser is described and demonstrated experimentally, which employs delayed-time fibers and angular multiplexing technique and can realize the variable temporal resolution at nanosecond scale and different measured depths of object field at certain temporal resolution. The actual delay-time is controlled by two delayed-time fibers with different lengths. The object field information in two different states can be simultaneously recorded in a composite hologram. This scheme is also suitable for recording fast process at picosecond scale, by using an electro-optic modulator.

  6. Digital-Analog Hybrid Scheme and Its Application to Chaotic Random Number Generators

    Science.gov (United States)

    Yuan, Zeshi; Li, Hongtao; Miao, Yunchi; Hu, Wen; Zhu, Xiaohua

    2017-12-01

    Practical random number generation (RNG) circuits are typically achieved with analog devices or digital approaches. Digital-based techniques, which use field programmable gate array (FPGA) and graphics processing units (GPU) etc. usually have better performances than analog methods as they are programmable, efficient and robust. However, digital realizations suffer from the effect of finite precision. Accordingly, the generated random numbers (RNs) are actually periodic instead of being real random. To tackle this limitation, in this paper we propose a novel digital-analog hybrid scheme that employs the digital unit as the main body, and minimum analog devices to generate physical RNs. Moreover, the possibility of realizing the proposed scheme with only one memory element is discussed. Without loss of generality, we use the capacitor and the memristor along with FPGA to construct the proposed hybrid system, and a chaotic true random number generator (TRNG) circuit is realized, producing physical RNs at a throughput of Gbit/s scale. These RNs successfully pass all the tests in the NIST SP800-22 package, confirming the significance of the scheme in practical applications. In addition, the use of this new scheme is not restricted to RNGs, and it also provides a strategy to solve the effect of finite precision in other digital systems.

  7. Digital modulation schemes for high speed transmission through low bandwidth lowpass analog links

    Science.gov (United States)

    Andrawis, Alfred S.; Flippin, Quentin J.

    1995-01-01

    Existing NTSC (National Television System Committee) standard will be phased out and replaced with HDTV (High Definition Television) standard within the next 10 years. Accordingly, the existing video network system operated by NASA will become obsolete and requires either replacement or modification to accommodate digital transmission. Network replacement is extremely expensive, hence, several digital modulation schemes are investigated in this report to accomplish digital transmission over existing analog links saving NASA from the cost of network replacement. There are two competing transmission systems available for HDTV transmission over limited bandwidth channels. The cost and performance of the two competing schemes are remarkably similar. However, the input data rate in such a case is limited to 40 Mbit/s. Transmission of higher data rates is possible using simple signal processing techniques. On the other hand, a third transmission system, multilevel pulse amplitude modulation (M-PAM) is proposed. M-PAM is the first stage of the well known M-VSB. This M-PAM scheme is much simpler and uses the channel more efficiently. The three schemes are compared and preliminary conclusions were made. Despite of several similarities, each modulation scheme has it unique merits. To determine the suitability of each scheme, more investigations and laboratory tests for all schemes are needed.

  8. Research on digital PID control algorithm for HPCT

    International Nuclear Information System (INIS)

    Zeng Yi; Li Rui; Shen Tianjian; Ke Xinhua

    2009-01-01

    Digital PID applied in high-precision HPCT (High-precision current transducer) based on Digital Signal Processor (DSP) TMS320F2812 and special D/A converter was researched. By using increment style PID Control algorithm, the stability and precision of high-precision HPCT output voltage is improved. On basis of deeply analysing incremental digital PID, the scheme model of HPCT is proposed, the feasibility simulation using Matlab is given. Practical hardware circuit verified the incremental PID has closed-loop control process in tracking HPCT output voltage. (authors)

  9. Classification of Digital Modulation Schemes Using Linear and Nonlinear Classifiers

    Science.gov (United States)

    2010-03-01

    Submitted in partial fulfillment of the requirements for the degrees of ELECTRICAL ENGINEER and MASTER OF SCIENCE IN ELECTRICAL ENGINEERING...7889 3050 1 121 7 29 11098 QPSK 0 0 0 0 5452 241 2655 331 2264 10943 8PSK 0 0 0 0 0 11071 0 0 0 11071 16QAM 0 0 0 0 0 1158 1952 1719 6380 11209 64QAM...Identification of Digital Signals by the Wavelet Transform,” Radar, Sonar and Navigation, IEE Proceedings, Vol. 147, Issue 4, pp. 169–176, 2000. [7] P

  10. A hybrid pi control scheme for airship hovering

    International Nuclear Information System (INIS)

    Ashraf, Z.; Choudhry, M.A.; Hanif, A.

    2012-01-01

    Airship provides us many attractive applications in aerospace industry including transportation of heavy payloads, tourism, emergency management, communication, hover and vision based applications. Hovering control of airship has many utilizations in different engineering fields. However, it is a difficult problem to sustain the hover condition maintaining controllability. So far, different solutions have been proposed in literature but most of them are difficult in analysis and implementation. In this paper, we have presented a simple and efficient scheme to design a multi input multi output hybrid PI control scheme for airship. It can maintain stability of the plant by rejecting disturbance inputs to ensure robustness. A control scheme based on feedback theory is proposed that uses principles of optimality with integral action for hovering applications. Simulations are carried out in MTALAB for examining the proposed control scheme for hovering in different wind conditions. Comparison of the technique with an existing scheme is performed, describing the effectiveness of control scheme. (author)

  11. An encryption scheme based on phase-shifting digital holography and amplitude-phase disturbance

    International Nuclear Information System (INIS)

    Hua Li-Li; Xu Ning; Yang Geng

    2014-01-01

    In this paper, we propose an encryption scheme based on phase-shifting digital interferometry. According to the original system framework, we add a random amplitude mask and replace the Fourier transform by the Fresnel transform. We develop a mathematical model and give a discrete formula based on the scheme, which makes it easy to implement the scheme in computer programming. The experimental results show that the improved system has a better performance in security than the original encryption method. Moreover, it demonstrates a good capability of anti-noise and anti-shear robustness

  12. Digital control programmer for temperature control

    International Nuclear Information System (INIS)

    Rajore, S.B.; Kumar, S.V.

    1993-01-01

    This report describes a PC based digital control programmer for controlling and programming temperature of a high vacuum resistance heating furnace and the software developed to control power using PID algorithm. It also describes the amplifier specially developed to suit the input requirement of the non-standard W5 thermocouple and the software and hardware protections introduced in the system. (author). 5 refs., 8 figs., 1 appendix

  13. Effect of prosthodontic planning on lateral occlusion scheme: a comparison between conventional and digital planning.

    Science.gov (United States)

    Abduo, Jaafar; Bennamoun, Mohammed; Tennant, Marc; McGeachie, John

    2015-01-01

    Recently, digital wax-up is proposed as a tool to aid prosthodontic planning. However, there are no data about the effect of prosthodontic planning on lateral occlusion scheme. This study aims to evaluate the impact of conventional and digital prosthodontic planning on lateral occlusion scheme. Dental models of 10 patients were collected. All models had Angle Class I occlusion and were undergoing prosthodontic treatment that would influence the lateral occlusion scheme. Each set of models had received both conventional wax-up and digital wax-up. In relation to the lateral occlusion scheme, the following variables were evaluated: the prevalence of the different lateral occlusion scheme, number of contacting teeth and percentage of each contacting tooth. Four excursive positions on the working side were included: 0.5, 1.0, 2.0 and 3.0 mm from the maximal intercuspation position. The lateral occlusion scheme of the two wax-up models was subjected to alterations following excursion. There was a tendency for the prevalence of canine-guided occlusion to increase and for the prevalence of group function occlusion to decrease with increasing excursion. The number of contacting teeth was decreasing with the increasing magnitude of excursion. For the 0.5 mm and 1.0 mm positions, the two wax-ups had significantly greater contacts than the pre-treatment models, while at the 2.0 mm and 3.0 mm positions, all the models were similar. For all models, canines were the most commonly contacting teeth, followed by the teeth adjacent to them. No difference was observed between the two wax-ups in relation to the number of contacting teeth. Although the prosthodontic planning had influenced the pattern of the lateral occlusion scheme and contacts, there was no difference between the conventional and digital prosthodontic planning.

  14. Automatic breast tissue density estimation scheme in digital mammography images

    Science.gov (United States)

    Menechelli, Renan C.; Pacheco, Ana Luisa V.; Schiabel, Homero

    2017-03-01

    Cases of breast cancer have increased substantially each year. However, radiologists are subject to subjectivity and failures of interpretation which may affect the final diagnosis in this examination. The high density features in breast tissue are important factors related to these failures. Thus, among many functions some CADx (Computer-Aided Diagnosis) schemes are classifying breasts according to the predominant density. In order to aid in such a procedure, this work attempts to describe automated software for classification and statistical information on the percentage change in breast tissue density, through analysis of sub regions (ROIs) from the whole mammography image. Once the breast is segmented, the image is divided into regions from which texture features are extracted. Then an artificial neural network MLP was used to categorize ROIs. Experienced radiologists have previously determined the ROIs density classification, which was the reference to the software evaluation. From tests results its average accuracy was 88.7% in ROIs classification, and 83.25% in the classification of the whole breast density in the 4 BI-RADS density classes - taking into account a set of 400 images. Furthermore, when considering only a simplified two classes division (high and low densities) the classifier accuracy reached 93.5%, with AUC = 0.95.

  15. Key-Insulated Undetachable Digital Signature Scheme and Solution for Secure Mobile Agents in Electronic Commerce

    Directory of Open Access Journals (Sweden)

    Yang Shi

    2016-01-01

    Full Text Available Considering the security of both the customers’ hosts and the eShops’ servers, we introduce the idea of a key-insulated undetachable digital signature, enabling mobile agents to generate undetachable digital signatures on remote hosts with the key-insulated property of the original signer’s signing key. From the theoretical perspective, we provide the formal definition and security notion of a key-insulated undetachable digital signature. From the practical perspective, we propose a concrete scheme to secure mobile agents in electronic commerce. The scheme is mainly focused on protecting the signing key from leakage and preventing the misuse of the signature algorithm on malicious servers. Agents do not carry the signing key when they generate digital signatures on behalf of the original signer, so the key is protected on remote servers. Furthermore, if a hacker gains the signing key of the original signer, the hacker is still unable to forge a signature for any time period other than the key being accessed. In addition, the encrypted function is combined with the original signer’s requirement to prevent the misuse of signing algorithm. The scheme is constructed on gap Diffie–Hellman groups with provable security, and the performance testing indicates that the scheme is efficient.

  16. Public-key quantum digital signature scheme with one-time pad private-key

    Science.gov (United States)

    Chen, Feng-Lin; Liu, Wan-Fang; Chen, Su-Gen; Wang, Zhi-Hua

    2018-01-01

    A quantum digital signature scheme is firstly proposed based on public-key quantum cryptosystem. In the scheme, the verification public-key is derived from the signer's identity information (such as e-mail) on the foundation of identity-based encryption, and the signature private-key is generated by one-time pad (OTP) protocol. The public-key and private-key pair belongs to classical bits, but the signature cipher belongs to quantum qubits. After the signer announces the public-key and generates the final quantum signature, each verifier can verify publicly whether the signature is valid or not with the public-key and quantum digital digest. Analysis results show that the proposed scheme satisfies non-repudiation and unforgeability. Information-theoretic security of the scheme is ensured by quantum indistinguishability mechanics and OTP protocol. Based on the public-key cryptosystem, the proposed scheme is easier to be realized compared with other quantum signature schemes under current technical conditions.

  17. Centralized digital control of accelerators

    International Nuclear Information System (INIS)

    Melen, R.E.

    1983-09-01

    In contrasting the title of this paper with a second paper to be presented at this conference entitled Distributed Digital Control of Accelerators, a potential reader might be led to believe that this paper will focus on systems whose computing intelligence is centered in one or more computers in a centralized location. Instead, this paper will describe the architectural evolution of SLAC's computer based accelerator control systems with respect to the distribution of their intelligence. However, the use of the word centralized in the title is appropriate because these systems are based on the use of centralized large and computationally powerful processors that are typically supported by networks of smaller distributed processors

  18. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    In this communication, simulation studies on the effectiveness of using Proportional Integral (P-I) control schemes for managing charge balance in electrical stimulation are presented. The adaptation of the P-I control scheme to implant circuits leads to two possible circuit realizations in the analog domain. The governing ...

  19. Dynamic Evaluation of LCL-type Grid-Connected Inverters with Different Current Feedback Control Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Li, Zipeng; Guerrero, Josep M.

    2015-01-01

    typical current feedback control schemes in LCL grid-connected system are analyzed and compared systematically. Analysis in s-domain take the effect of the digital computation and modulation delay into account. The stability analysis is presented by root locus in the discrete domain, the optimal values...... of the controller and filter with different feedback configurations are provided. The impacts of digital delay, PR parameters and LCL parameters on different control strategies are also investigated. Finally, the theoretical analysis are validated by simulation results....

  20. Digital control of research reactors

    International Nuclear Information System (INIS)

    Crump, J.C. III.; Richards, W.J.; Heidel, C.C.

    1991-01-01

    Research reactors provide an important service for the nuclear industry. Developments and innovations used for research reactors can be later applied to larger power reactors. Their relatively inexpensive cost allows research reactors to be an excellent testing ground for the reactors of tomorrow. One area of current interest is digital control of research reactor systems. Digital control systems offer the benefits of implementation and superior system response over their analog counterparts. At McClellan Air Force Base in Sacramento, California, the Stationary Neutron Radiography System (SNRS) uses a 1,000-kW TRIGA reactor for neutron radiography and other nuclear research missions. The neutron radiography beams generated by the reactor are used to detect corrosion in aircraft structures. While the use of the reactor to inspect intact F-111 wings is in itself noteworthy, there is another area in which the facility has applied new technology: the instrumentation and control system (ICS). The ICS developed by General Atomics (GA) contains several new and significant items: (a) the ability to servocontrol on three rods, (b) the ability to produce a square wave, and (c) the use of a software configurator to tune parameters affected by the actual reactor core dynamics. These items will probably be present in most, if not all, future research reactors. They were developed with increased control and overall usefulness of the reactor in mind

  1. Digital control rod blocking monitor

    International Nuclear Information System (INIS)

    Funayama, Yoshio.

    1996-01-01

    The present invention system is used for monitoring of a power region of a reactor, and used for monitoring of simultaneous withdrawal of a plurality of control rods without increasing the size or complicating the system. Namely, the system processes signals from a neutron flux detectors at the periphery of control rods controlled for withdrawal. As a result of the processing, the digital monitoring system generates an alarm when the reactor power at the periphery of the control rods fluctuates exceeding an allowable range. In the system, a control rod information forming means prepares frame data comprising front data, positions of the control rods to be withdrawn, frame numbers and completion data. A serial data transmitting means transmits the frame data successively as repeating frame data rows. A control rod information receiving means takes up the frame data of each of control rods to be withdrawn from the transmitted frame data rows. Since the system of the present invention can monitor the withdrawal of a plurality of control rods simultaneously without increasing the size or complicating the system, cost can be saved and the maintenance can be improved. (I.S.)

  2. GMA200 ATEGG Digital Controls Demonstration.

    Science.gov (United States)

    1979-10-01

    controlled on corrected speed by the digital controller through an Electro-Hydraulic Servo Valve ( EHSV ) and a position transducer. A pair of hydraulic...nozzle is hydraulically actuated. The digital controller effects position control via an EHSV and position transducers. e. Engine Sensors In addition...A-AG93 958 GENERAL MOTORS CORP INDIANAPOLIS IN DETROIT DIESEL A-ETC F/6 1/ r A - 3 5.S o79 GAM200 ATEGG DIGITAL CONTROLS DEMONSTRATION.(U) OCT 79 D

  3. Differential on-on keying: A robust non-coherent digital modulation scheme

    KAUST Repository

    Kaddoum, Georges

    2015-05-01

    A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

  4. Digital control card based on digital signal processor

    International Nuclear Information System (INIS)

    Hou Shigang; Yin Zhiguo; Xia Le

    2008-01-01

    A digital control card based on digital signal processor was developed. Two Freescale DSP-56303 processors were utilized to achieve 3 channels proportional- integral-differential regulations. The card offers high flexibility for 100 MeV cyclotron RF system development. It was used as feedback controller in low level radio frequency control prototype, with the feedback gain parameters continuously adjustable. By using high precision analog to digital converter with 500 kHz sampling rate, a regulation bandwidth of 20 kHz was achieved. (authors)

  5. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    parator and an FIR filter, and the scheme was validated in simulation by studying the step responses of the system. In a similar scheme in [11], a P-I controller was used ...... [6] Sooksood K, Stieglitz T and Ortmanns M 2009 An experimen- tal study on passive charge balancing. Adv. Radio Sci. 7(15):. 197–200. [7] Lee E K F ...

  6. Linear and nonlinear schemes applied to pitch control of wind turbines.

    Science.gov (United States)

    Geng, Hua; Yang, Geng

    2014-01-01

    Linear controllers have been employed in industrial applications for many years, but sometimes they are noneffective on the system with nonlinear characteristics. This paper discusses the structure, performance, implementation cost, advantages, and disadvantages of different linear and nonlinear schemes applied to the pitch control of the wind energy conversion systems (WECSs). The linear controller has the simplest structure and is easily understood by the engineers and thus is widely accepted by the industry. In contrast, nonlinear schemes are more complicated, but they can provide better performance. Although nonlinear algorithms can be implemented in a powerful digital processor nowadays, they need time to be accepted by the industry and their reliability needs to be verified in the commercial products. More information about the system nonlinear feature is helpful to simplify the controller design. However, nonlinear schemes independent of the system model are more robust to the uncertainties or deviations of the system parameters.

  7. A Hybrid Nonlinear Control Scheme for Active Magnetic Bearings

    Science.gov (United States)

    Xia, F.; Albritton, N. G.; Hung, J. Y.; Nelms, R. M.

    1996-01-01

    A nonlinear control scheme for active magnetic bearings is presented in this work. Magnet winding currents are chosen as control inputs for the electromechanical dynamics, which are linearized using feedback linearization. Then, the desired magnet currents are enforced by sliding mode control design of the electromagnetic dynamics. The overall control scheme is described by a multiple loop block diagram; the approach also falls in the class of nonlinear controls that are collectively known as the 'integrator backstepping' method. Control system hardware and new switching power electronics for implementing the controller are described. Various experiments and simulation results are presented to demonstrate the concepts' potentials.

  8. An automatic computer-aided detection scheme for pneumoconiosis on digital chest radiographs.

    Science.gov (United States)

    Yu, Peichun; Xu, Hao; Zhu, Ying; Yang, Chao; Sun, Xiwen; Zhao, Jun

    2011-06-01

    This paper presents an automatic computer-aided detection scheme on digital chest radiographs to detect pneumoconiosis. Firstly, the lung fields are segmented from a digital chest X-ray image by using the active shape model method. Then, the lung fields are subdivided into six non-overlapping regions, according to Chinese diagnosis criteria of pneumoconiosis. The multi-scale difference filter bank is applied to the chest image to enhance the details of the small opacities, and the texture features are calculated from each region of the original and the processed images, respectively. After extracting the most relevant ones from the feature sets, support vector machine classifiers are utilized to separate the samples into the normal and the abnormal sets. Finally, the final classification is performed by the chest-based report-out and the classification probability values of six regions. Experiments are conducted on randomly selected images from our chest database. Both the training and the testing sets have 300 normal and 125 pneumoconiosis cases. In the training phase, training models and weighting factors for each region are derived. We evaluate the scheme using the full feature vectors or the selected feature vectors of the testing set. The results show that the classification performances are high. Compared with the previous methods, our fully automated scheme has a higher accuracy and a more convenient interaction. The scheme is very helpful to mass screening of pneumoconiosis in clinic.

  9. An ECC-Based Blind Signcryption Scheme for Multiple Digital Documents

    Directory of Open Access Journals (Sweden)

    Chien-Hua Tsai

    2017-01-01

    Full Text Available The popularity of the Internet has comprehensively altered the traditional way of communication and interaction patterns, such as e-contract negotiations, e-payment services, or digital credential processes. In the field of e-form systems, a number of studies investigate the ability of the blind signature to fulfill the basic properties of blindness and untraceability. However, most literatures exploring the blind signature mechanisms only address research and technology pertaining to single blind signature issues. Further, most of the topics only deal with signing rather than encryption. Thus, we propose a new blind signature scheme for multiple digital documents based on elliptic curve cryptography (ECC. Our scheme incorporates the design of signcryption paradigm into the blind signature scheme to strengthen high levels of security. This innovative method also enhances computational efficiency during processing multiple electronic documents since the ECC provides a shorter key length and higher processing speed than other public-key cryptosystems on equivalent secrecy. The analysis results show that the present scheme achieves better performance at low communication overheads as well as with higher level of security. By helping the design of the intrinsic properties, the proposed cryptosystem can be applied to many areas to protect sensitive data in ubiquitous computing environments.

  10. An effective and secure key-management scheme for hierarchical access control in E-medicine system.

    Science.gov (United States)

    Odelu, Vanga; Das, Ashok Kumar; Goswami, Adrijit

    2013-04-01

    Recently several hierarchical access control schemes are proposed in the literature to provide security of e-medicine systems. However, most of them are either insecure against 'man-in-the-middle attack' or they require high storage and computational overheads. Wu and Chen proposed a key management method to solve dynamic access control problems in a user hierarchy based on hybrid cryptosystem. Though their scheme improves computational efficiency over Nikooghadam et al.'s approach, it suffers from large storage space for public parameters in public domain and computational inefficiency due to costly elliptic curve point multiplication. Recently, Nikooghadam and Zakerolhosseini showed that Wu-Chen's scheme is vulnerable to man-in-the-middle attack. In order to remedy this security weakness in Wu-Chen's scheme, they proposed a secure scheme which is again based on ECC (elliptic curve cryptography) and efficient one-way hash function. However, their scheme incurs huge computational cost for providing verification of public information in the public domain as their scheme uses ECC digital signature which is costly when compared to symmetric-key cryptosystem. In this paper, we propose an effective access control scheme in user hierarchy which is only based on symmetric-key cryptosystem and efficient one-way hash function. We show that our scheme reduces significantly the storage space for both public and private domains, and computational complexity when compared to Wu-Chen's scheme, Nikooghadam-Zakerolhosseini's scheme, and other related schemes. Through the informal and formal security analysis, we further show that our scheme is secure against different attacks and also man-in-the-middle attack. Moreover, dynamic access control problems in our scheme are also solved efficiently compared to other related schemes, making our scheme is much suitable for practical applications of e-medicine systems.

  11. Time-division-multiplex control scheme for voltage multiplier rectifiers

    Directory of Open Access Journals (Sweden)

    Bin-Han Liu

    2017-03-01

    Full Text Available A voltage multiplier rectifier with a novel time-division-multiplexing (TDM control scheme for high step-up converters is proposed in this study. In the proposed TDM control scheme, two full-wave voltage doubler rectifiers can be combined to realise a voltage quadrupler rectifier. The proposed voltage quadrupler rectifier can reduce transformer turn ratio and transformer size for high step-up converters and also reduce voltage stress for the output capacitors and rectifier diodes. An N-times voltage rectifier can be straightforwardly produced by extending the concepts from the proposed TDM control scheme. A phase-shift full-bridge (PSFB converter is adopted in the primary side of the proposed voltage quadrupler rectifier to construct a PSFB quadrupler converter. Experimental results for the PSFB quadrupler converter demonstrate the performance of the proposed TDM control scheme for voltage quadrupler rectifiers. An 8-times voltage rectifier is simulated to determine the validity of extending the proposed TDM control scheme to realise an N-times voltage rectifier. Experimental and simulation results show that the proposed TDM control scheme has great potential to be used in high step-up converters.

  12. Centralized digital control of accelerators

    International Nuclear Information System (INIS)

    Melen, R.E.

    1984-01-01

    Upon careful examination of the architecture of SLAC's computer control systems, it becomes evident that the distribution of the systems' intelligence generally falls into tree-like layers. The first layer typically consists of a central computer complex incorporating one or more relatively large and powerful processors. The more modern systems use state-of-the-art 32-bit processors with several megabytes of RAM and several hundreds of megabytes of disk memory. Further, they support extensive user-friendly operating systems and program development facilities. The second layer typically consists of several smaller processors which are downloaded from the central complex and whose primary task is to provide data acquisition and distribution. The more modern systems are 16-bit processors with several hundred kilobytes of RAM and no disk memory. The third layer typically consists of several tens or hundreds of micro-processors, each dedicated to a single device. The micro-processors for these ''dedicated intelligent controllers'' are small and inexpensive and typically require less than 32 kilobytes of RAM or EPROM memory. Their hardware may be general purpose in nature or may be built into the architecture of the device itself. Figure 5 illustrates several of the relevant features of each of these layers. This paper serves to illustrate that SLAC is commited to the centralized digital control of its accelerators

  13. Stability Analysis and Controller Synthesis for Digital Single-Loop Voltage-Controlled Inverters

    DEFF Research Database (Denmark)

    Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede

    2016-01-01

    This paper analyzes first the stability of single-loop digital voltage control scheme for the LC-filtered voltage source inverters. It turns out that the phase lag, caused by the time delay of digital control system and by the use of integral controller, can stabilize the voltage loop without...... damping of LC-filter resonance. The stability regions are then identified with alternative voltage controller synthesized. For further widening the stability region, an active damping approach is proposed and co-designed with the voltage controller in the discrete z-domain. Simulations and experimental...

  14. A novel robust speed controller scheme for PMBLDC motor.

    Science.gov (United States)

    Thirusakthimurugan, P; Dananjayan, P

    2007-10-01

    The design of speed and position controllers for permanent magnet brushless DC motor (PMBLDC) drive remains as an open problem in the field of motor drives. A precise speed control of PMBLDC motor is complex due to nonlinear coupling between winding currents and rotor speed. In addition, the nonlinearity present in the developed torque due to magnetic saturation of the rotor further complicates this issue. This paper presents a novel control scheme to the conventional PMBLDC motor drive, which aims at improving the robustness by complete decoupling of the design besides minimizing the mutual influence among the speed and current control loops. The interesting feature of this robust control scheme is its suitability for both static and dynamic aspects. The effectiveness of the proposed robust speed control scheme is verified through simulations.

  15. Design and simulation of advanced fault tolerant flight control schemes

    Science.gov (United States)

    Gururajan, Srikanth

    This research effort describes the design and simulation of a distributed Neural Network (NN) based fault tolerant flight control scheme and the interface of the scheme within a simulation/visualization environment. The goal of the fault tolerant flight control scheme is to recover an aircraft from failures to its sensors or actuators. A commercially available simulation package, Aviator Visual Design Simulator (AVDS), was used for the purpose of simulation and visualization of the aircraft dynamics and the performance of the control schemes. For the purpose of the sensor failure detection, identification and accommodation (SFDIA) task, it is assumed that the pitch, roll and yaw rate gyros onboard are without physical redundancy. The task is accomplished through the use of a Main Neural Network (MNN) and a set of three De-Centralized Neural Networks (DNNs), providing analytical redundancy for the pitch, roll and yaw gyros. The purpose of the MNN is to detect a sensor failure while the purpose of the DNNs is to identify the failed sensor and then to provide failure accommodation. The actuator failure detection, identification and accommodation (AFDIA) scheme also features the MNN, for detection of actuator failures, along with three Neural Network Controllers (NNCs) for providing the compensating control surface deflections to neutralize the failure induced pitching, rolling and yawing moments. All NNs continue to train on-line, in addition to an offline trained baseline network structure, using the Extended Back-Propagation Algorithm (EBPA), with the flight data provided by the AVDS simulation package. The above mentioned adaptive flight control schemes have been traditionally implemented sequentially on a single computer. This research addresses the implementation of these fault tolerant flight control schemes on parallel and distributed computer architectures, using Berkeley Software Distribution (BSD) sockets and Message Passing Interface (MPI) for inter

  16. Optical identity authentication scheme based on elliptic curve digital signature algorithm and phase retrieval algorithm.

    Science.gov (United States)

    Fan, Desheng; Meng, Xiangfeng; Wang, Yurong; Yang, Xiulun; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2013-08-10

    An optical identity authentication scheme based on the elliptic curve digital signature algorithm (ECDSA) and phase retrieval algorithm (PRA) is proposed. In this scheme, a user's certification image and the quick response code of the user identity's keyed-hash message authentication code (HMAC) with added noise, serving as the amplitude and phase restriction, respectively, are digitally encoded into two phase keys using a PRA in the Fresnel domain. During the authentication process, when the two phase keys are presented to the system and illuminated by a plane wave of correct wavelength, an output image is generated in the output plane. By identifying whether there is a match between the amplitude of the output image and all the certification images pre-stored in the database, the system can thus accomplish a first-level verification. After the confirmation of first-level verification, the ECDSA signature is decoded from the phase part of the output image and verified to allege whether the user's identity is legal or not. Moreover, the introduction of HMAC makes it almost impossible to forge the signature and hence the phase keys thanks to the HMAC's irreversible property. Theoretical analysis and numerical simulations both validate the feasibility of our proposed scheme.

  17. An Industrial Model Based Disturbance Feedback Control Scheme

    DEFF Research Database (Denmark)

    Kawai, Fukiko; Nakazawa, Chikashi; Vinther, Kasper

    2014-01-01

    This paper presents a model based disturbance feedback control scheme. Industrial process systems have been traditionally controlled by using relay and PID controller. However these controllers are affected by disturbances and model errors and these effects degrade control performance. The authors...... propose a new control method that can decrease the negative impact of disturbance and model errors. The control method is motivated by industrial practice by Fuji Electric. Simulation tests are examined with a conventional PID controller and the disturbance feedback control. The simulation results...... demonstrate the effectiveness of the proposed method comparing with the conventional PID controller...

  18. Automation of the control scheme for IUAC Linac

    International Nuclear Information System (INIS)

    Sahu, B.K.; Dutt, R.N.; Antony, J.; Mathuria, D.S.; Pandey, A.; Singh, K.; Ahuja, R.; Chowdhury, G.K.; Rai, A.; Patra, P.; Ghosh, S.; Ajithkumar, B.P.; Kanjilal, D.; Roy, A.

    2011-01-01

    Improvement of the Linac control scheme is undertaken for automation with minimum human intervention during beam acceleration. Python language interface with the present control scheme is used in writing automation routines to monitor the status of the phase/amplitude lock during operation and shut-down the locking mechanism to reduce the RF power, if required. Simultaneous pulse conditioning of the resonators is made possible by using dedicated hardware interfaced and Python based client interface. Movement of the drive coupler is enabled from operation console with position read back. The manual control of the slow-tuner electronics module to bring the frequency close to reference during phase locking is interfaced with the present control scheme for remote operation. Monitoring of amplitude and absolute phase of each cavity is made possible from operation console. An alternate tuning mechanism using piezoelectric actuator and stepper motor combination has been successfully tested in the test cryostat. (author)

  19. Robust Fallback Scheme for the Danish Automatic Voltage Control System

    DEFF Research Database (Denmark)

    Qin, Nan; Dmitrova, Evgenia; Lund, Torsten

    2015-01-01

    This paper proposes a fallback scheme for the Danish automatic voltage control system. It will be activated in case of the local station loses telecommunication to the control center and/or the local station voltage violates the acceptable operational limits. It cuts in/out switchable and tap...

  20. A hybrid iterative scheme for optimal control problems governed by ...

    African Journals Online (AJOL)

    A hybrid iterative scheme for optimal control problems governed by some Fredholm Integral Equations. ... Global Journal of Mathematical Sciences ... based on hybrid of perturbation and parametrization methods for obtaining approximate solutions of optimal control problems governed by some Fredholm integral equations.

  1. Interface control scheme for computer high-speed interface unit

    Science.gov (United States)

    Ballard, B. K.

    1975-01-01

    Control scheme is general and performs for multiplexed and dedicated channels as well as for data-bus interfaces. Control comprises two 64-pin, dual in-line packages, each of which holds custom large-scale integrated array built with silicon-on-sapphire complementary metal-oxide semiconductor technology.

  2. A digital control system for neutron spectrometers

    DEFF Research Database (Denmark)

    Hansen, Knud Bent; Skaarup, Per

    1968-01-01

    A description is given of the principles of a digital system used to control neutron spectrometers. The system is composed of independent functional units with the control programme stored on punched paper tape or in a computer.......A description is given of the principles of a digital system used to control neutron spectrometers. The system is composed of independent functional units with the control programme stored on punched paper tape or in a computer....

  3. A digital data acquisition scheme for SPECT and PET small animal imaging detectors for Theranostic applications

    Science.gov (United States)

    Georgiou, M.; Fysikopoulos, E.; Loudos, G.

    2017-11-01

    Nanoparticle based drug delivery is considered as a new, promising technology for the efficient treatment of various diseases. When nanoparticles are radiolabelled it is possible to image them, using molecular imaging techniques. The use of magnetic nanoparticles in hyperthermia is one of the most promising nanomedicine directions and requires the accurate, non-invasive, monitoring of temperature increase and drug release. The combination of imaging and therapy has opened the very promising Theranostics domain. In this work, we present a digital data acquisition scheme for nuclear medicine dedicated detectors for Theranostic applications.

  4. 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.

  5. Digital control system of advanced reactor

    International Nuclear Information System (INIS)

    Peng Huaqing; Zhang Rui; Liu Lixin

    2001-01-01

    This article produced the Digital Control System For Advanced Reactor made by NPIC. This system uses Siemens SIMATIC PCS 7 process control system and includes five control system: reactor power control system, pressurizer level control system, pressurizer pressure control system, steam generator water level control system and dump control system. This system uses three automatic station to realize the function of five control system. Because the safety requisition of reactor is very strict, the system is redundant. The system configuration uses CFC and SCL. the human-machine interface is configured by Wincc. Finally the system passed the test of simulation by using RETRAN 02 to simulate the control object. The research solved the key technology of digital control system of reactor and will be very helpful for the nationalization of digital reactor control system

  6. Two schemes for rapid generation of digital video holograms using PC cluster

    Science.gov (United States)

    Park, Hanhoon; Song, Joongseok; Kim, Changseob; Park, Jong-Il

    2017-12-01

    Computer-generated holography (CGH), which is a process of generating digital holograms, is computationally expensive. Recently, several methods/systems of parallelizing the process using graphic processing units (GPUs) have been proposed. Indeed, use of multiple GPUs or a personal computer (PC) cluster (each PC with GPUs) enabled great improvements in the process speed. However, extant literature has less often explored systems involving rapid generation of multiple digital holograms and specialized systems for rapid generation of a digital video hologram. This study proposes a system that uses a PC cluster and is able to more efficiently generate a video hologram. The proposed system is designed to simultaneously generate multiple frames and accelerate the generation by parallelizing the CGH computations across a number of frames, as opposed to separately generating each individual frame while parallelizing the CGH computations within each frame. The proposed system also enables the subprocesses for generating each frame to execute in parallel through multithreading. With these two schemes, the proposed system significantly reduced the data communication time for generating a digital hologram when compared with that of the state-of-the-art system.

  7. A Digitization Scheme of Sub-Microampere Current Using a Commercial Comparator with Hysteresis and FPGA-Based Wave Union TDC

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jinyuan [Fermilab

    2012-11-01

    A digitization scheme of sub-microampere current using a commercial comparator with adjustable hysteresis and FPGA-based Wave Union TDC has been tested. The comparator plus a few passive components forms a current controlled oscillator and the input current is sent into the hysteresis control pin. The input current is converted into the transition times of the oscillations, which are digitized with a Wave Union TDC in FPGA and the variation of the transition times reflects the variation of the input current. Preliminary tests show that input charges < 25 fC can be measured at > 50 M samples/s without a preamplifier.

  8. Hierarchical Control Scheme for Voltage Unbalance Compensation in Islanded Microgrids

    DEFF Research Database (Denmark)

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

    2011-01-01

    The concept of microgrid hierarchical control is presented, recently. In this paper, a hierarchical scheme which includes primary and secondary control levels is proposed for islanded microgrids. The primary control level consists of DG local controllers. Local controller of each DG comprises...... active and reactive power controllers, virtual impedance loop and voltage and current controllers. The secondary level is designed to compensate the voltage unbalance at the load bus (LB) of the islanded microgrid. Also, restoration of LB voltage amplitude and microgrid frequency to the rated values...

  9. Improved performance of the control scheme for IUAC superconducting Linac

    International Nuclear Information System (INIS)

    Sahu, B.K.; Suman, S.K.; Kumar, R.

    2015-01-01

    Since many years energized ion beams from linac are being delivered routinely for scheduled experiments using all the three accelerating modules of linac along with super buncher and rebuncher. Major efforts are dedicated to improve the performance of the control scheme to minimise the down time of the linac during operation. Earlier, a number of developments were carried out to improve the dynamics of the control scheme. The most significant of them is the piezoelectric actuator based tuning mechanism which is implemented in all the operational resonators of second and third accelerating modules of superconducting linac. This has helped us to bridge the gap between the accelerating fields achieved during Q measurement at 6 W of helium power and during phase locking of the resonator during beam operation at a given RF power (∼120W). The piezoelectric actuator based tuner is also instrumental to reduce the unlocking rate of the resonators. Pulse width modulation (PWM) control based helium gas operated tuner is implemented in few resonators to improve phase locking performance. CAMAC based distributed control scheme is upgraded to VME based distributed control without changing the existing client interface to maintain uniformity between the Pelletron and linac control. Python code support has been implemented to protect the resonators against high forward power during unlocking. This is also integrated with the display status of the resonators for monitoring. A frequency to voltage converter is incorporated in control scheme to monitor the frequency error. This has helped us to develop a scheme for automatic phase locking of the cavities using piezoelectric actuator based tuner control. (author)

  10. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

    The key attribute of a Fault Tolerant Control (FTC) system is its ability to maintain overall system stability and acceptable performance in the face of faults and failures within the feedback system. In this book Integral Sliding Mode (ISM) Control Allocation (CA) schemes for FTC are described, which have the potential to maintain close to nominal fault-free performance (for the entire system response), in the face of actuator faults and even complete failures of certain actuators. Broadly an ISM controller based around a model of the plant with the aim of creating a nonlinear fault tolerant feedback controller whose closed-loop performance is established during the design process. The second approach involves retro-fitting an ISM scheme to an existing feedback controller to introduce fault tolerance. This may be advantageous from an industrial perspective, because fault tolerance can be introduced without changing the existing control loops. A high fidelity benchmark model of a large transport aircraft is u...

  11. Advanced Digital Controller Development Program, Task I.

    Science.gov (United States)

    1982-07-01

    digital controller through an electra-hydraulic servo valve ( EHSV ) and a position transducer. A pair of hydraulic cylinders will actuate a bell crank...AD-A129 269 ADVANCED DIGITAL CONTROLLER DEVELOPMENT PROGRAM TASK 1 1/1 ()GENERAL MOTORS CORP INDIANAPOLIS IN DETROIT DIESEL ALLISON D0. d H HUNTER JL...BUREAU OF S IANDARDS I-63 A I-16 2 I "-I [ I1 I ? I I I I II I I AFWAL-TR-82-2047 ’ Advanced Digital Controller < Development Program, Task I Detroit

  12. A content-based digital image watermarking scheme resistant to local geometric distortions

    International Nuclear Information System (INIS)

    Yang, Hong-ying; Chen, Li-li; Wang, Xiang-yang

    2011-01-01

    Geometric distortion is known as one of the most difficult attacks to resist, as it can desynchronize the location of the watermark and hence cause incorrect watermark detection. Geometric distortion can be decomposed into two classes: global affine transforms and local geometric distortions. Most countermeasures proposed in the literature only address the problem of global affine transforms. It is a challenging problem to design a robust image watermarking scheme against local geometric distortions. In this paper, we propose a new content-based digital image watermarking scheme with good visual quality and reasonable resistance against local geometric distortions. Firstly, the robust feature points, which can survive various common image processing and global affine transforms, are extracted by using a multi-scale SIFT (scale invariant feature transform) detector. Then, the affine covariant local feature regions (LFRs) are constructed adaptively according to the feature scale and local invariant centroid. Finally, the digital watermark is embedded into the affine covariant LFRs by modulating the magnitudes of discrete Fourier transform (DFT) coefficients. By binding the watermark with the affine covariant LFRs, the watermark detection can be done without synchronization error. Experimental results show that the proposed image watermarking is not only invisible and robust against common image processing operations such as sharpening, noise addition, and JPEG compression, etc, but also robust against global affine transforms and local geometric distortions

  13. Adaptive Digital Watermarking Scheme Based on Support Vector Machines and Optimized Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Xiaoyi Zhou

    2018-01-01

    Full Text Available Digital watermarking is an effective solution to the problem of copyright protection, thus maintaining the security of digital products in the network. An improved scheme to increase the robustness of embedded information on the basis of discrete cosine transform (DCT domain is proposed in this study. The embedding process consisted of two main procedures. Firstly, the embedding intensity with support vector machines (SVMs was adaptively strengthened by training 1600 image blocks which are of different texture and luminance. Secondly, the embedding position with the optimized genetic algorithm (GA was selected. To optimize GA, the best individual in the first place of each generation directly went into the next generation, and the best individual in the second position participated in the crossover and the mutation process. The transparency reaches 40.5 when GA’s generation number is 200. A case study was conducted on a 256 × 256 standard Lena image with the proposed method. After various attacks (such as cropping, JPEG compression, Gaussian low-pass filtering (3,0.5, histogram equalization, and contrast increasing (0.5,0.6 on the watermarked image, the extracted watermark was compared with the original one. Results demonstrate that the watermark can be effectively recovered after these attacks. Even though the algorithm is weak against rotation attacks, it provides high quality in imperceptibility and robustness and hence it is a successful candidate for implementing novel image watermarking scheme meeting real timelines.

  14. Gemstones and geosciences in space and time. Digital maps to the "Chessboard classification scheme of mineral deposits"

    Science.gov (United States)

    Dill, Harald G.; Weber, Berthold

    2013-12-01

    The gemstones, covering the spectrum from jeweler's to showcase quality, have been presented in a tripartite subdivision, by country, geology and geomorphology realized in 99 digital maps with more than 2600 mineralized sites. The various maps were designed based on the "Chessboard classification scheme of mineral deposits" proposed by Dill (2010a, 2010b) to reveal the interrelations between gemstone deposits and mineral deposits of other commodities and direct our thoughts to potential new target areas for exploration. A number of 33 categories were used for these digital maps: chromium, nickel, titanium, iron, manganese, copper, tin-tungsten, beryllium, lithium, zinc, calcium, boron, fluorine, strontium, phosphorus, zirconium, silica, feldspar, feldspathoids, zeolite, amphibole (tiger's eye), olivine, pyroxenoid, garnet, epidote, sillimanite-andalusite, corundum-spinel - diaspore, diamond, vermiculite-pagodite, prehnite, sepiolite, jet, and amber. Besides the political base map (gems by country) the mineral deposit is drawn on a geological map, illustrating the main lithologies, stratigraphic units and tectonic structure to unravel the evolution of primary gemstone deposits in time and space. The geomorphological map is to show the control of climate and subaerial and submarine hydrography on the deposition of secondary gemstone deposits. The digital maps are designed so as to be plotted as a paper version of different scale and to upgrade them for an interactive use and link them to gemological databases.

  15. A new anti-forensic scheme--hiding the single JPEG compression trace for digital image.

    Science.gov (United States)

    Cao, Yanjun; Gao, Tiegang; Sheng, Guorui; Fan, Li; Gao, Lin

    2015-01-01

    To prevent image forgeries, a number of forensic techniques for digital image have been developed that can detect an image's origin, trace its processing history, and can also locate the position of tampering. Especially, the statistical footprint left by JPEG compression operation can be a valuable source of information for the forensic analyst, and some image forensic algorithm have been raised based on the image statistics in the DCT domain. Recently, it has been shown that footprints can be removed by adding a suitable anti-forensic dithering signal to the image in the DCT domain, this results in invalid for some image forensic algorithms. In this paper, a novel anti-forensic algorithm is proposed, which is capable of concealing the quantization artifacts that left in the single JPEG compressed image. In the scheme, a chaos-based dither is added to an image's DCT coefficients to remove such artifacts. Effectiveness of both the scheme and the loss of image quality are evaluated through the experiments. The simulation results show that the proposed anti-forensic scheme can verify the reliability of the JPEG forensic tools. © 2014 American Academy of Forensic Sciences.

  16. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    International Journal of Engineering, Science and Technology ... Wavelet based techniques have been extensively used in various power engineering applications. ... But, unlike other popular PWM schemes e.g. sinusoidal PWM, which offers independent control to both magnitude and frequency of fundamental inverter ...

  17. Provable Secure and Efficient Digital Rights Management Authentication Scheme Using Smart Card Based on Elliptic Curve Cryptography

    Directory of Open Access Journals (Sweden)

    Yuanyuan Zhang

    2015-01-01

    Full Text Available Since the concept of ubiquitous computing is firstly proposed by Mark Weiser, its connotation has been extending and expanding by many scholars. In pervasive computing application environment, many kinds of small devices containing smart cart are used to communicate with others. In 2013, Yang et al. proposed an enhanced authentication scheme using smart card for digital rights management. They demonstrated that their scheme is secure enough. However, Mishra et al. pointed out that Yang et al.’s scheme suffers from the password guessing attack and the denial of service attack. Moreover, they also demonstrated that Yang et al.’s scheme is not efficient enough when the user inputs an incorrect password. In this paper, we analyze Yang et al.’s scheme again, and find that their scheme is vulnerable to the session key attack. And, there are some mistakes in their scheme. To surmount the weakness of Yang et al.’s scheme, we propose a more efficient and provable secure digital rights management authentication scheme using smart card based on elliptic curve cryptography.

  18. Multiagent System-Based Wide-Area Protection and Control Scheme against Cascading Events

    DEFF Research Database (Denmark)

    Liu, Zhou; Chen, Zhe; Sun, Haishun

    2015-01-01

    In this paper, a multi agent system (MAS) based wide area protection and control scheme is proposed to deal with the long term voltage instability induced cascading trips. Based on sensitivity analysis between the relay operation margin and power system state variables, an optimal emergency control...... strategy. A hybrid simulation platform based on LabVIEW and real time digital simulator (RTDS) is set up to simulate a blackout case in the power system of Eastern Denmark and to demonstrate the effectiveness of the proposed MAS based protection strategy....

  19. An active interferometer-stabilization scheme with linear phase control

    DEFF Research Database (Denmark)

    Vardhan Krishnamachari, Vishnu; Andresen, Esben Ravn; Potma, Eric Olaf

    2006-01-01

    We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....

  20. Attitude Control of a Satellite by using Digital Signal Processing

    Directory of Open Access Journals (Sweden)

    Adirelle C. Santana

    2012-03-01

    Full Text Available This article has discussed the development of a three-axis attitude digital controller for an artificial satellite using a digital signal processor. The main motivation of this study is the attitude control system of the satellite Multi-Mission Platform, developed by the Brazilian National Institute for Space Research for application in different sort of missions. The controller design was based on the theory of the Linear Quadratic Gaussian Regulator, synthesized from the linearized model of the motion of the satellite, i.e., the kinematics and dynamics of attitude. The attitude actuators considered in this study are pairs of cold gas jets powered by a pulse width/pulse frequency modulator. In the first stage of the project development, a system controller for continuous time was studied with the aim of testing the adequacy of the adopted control. The next steps had included an analysis of discretization techniques, the setting time of sampling rate, and the testing of the digital version of the Linear Quadratic Gaussian Regulator controller in the MATLAB/SIMULINK. To fulfill the study, the controller was implemented in a digital signal processor, specifically the Blackfin BF537 from Analog Devices, along with the pulse width/pulse frequency modulator. The validation tests used a scheme of co-simulation, where the model of the satellite was simulated in MATLAB/SIMULINK, while the controller and modulator were processed in the digital signal processor with a tool called Processor-In-the-Loop, which acted as a data communication link between both environments.function and required time to achieve a given mission accuracy are determined, and results are provided as illustration.

  1. Anti-Windup Scheme for Practical Control of Positioning Systems

    Directory of Open Access Journals (Sweden)

    Wahyudi Tarig Faisal and Abdulgani Albagul

    2012-10-01

    Full Text Available Positioning systems generally need a good controller to achieve high accuracy, fast response and robustness. In addition, ease of controller design and simplicity of controller structure are very important for practical application.  For satisfying these requirements, nominal characteristic trajectory following controller (NCTF has been proposed as a practical point-to-point (PTP positioning control. However, the effect of actuator saturation can not be completely compensated for due to the integrator windup as the plant parameters vary. This paper presents a method to improve the NCTF controller for overcoming the problem of integrator windup using simple and classical tracking anti-windup scheme. The improved NCTF controller is evaluated through simulation using a rotary positioning system. The results show that the improved NCTF controller is adequate to compensate for the effect of integrator windup. Keywords: Positioning, point-to-point, integrator windup, compensation, controller, robustness.

  2. Digital chaos-masked optical encryption scheme enhanced by two-dimensional key space

    Science.gov (United States)

    Liu, Ling; Xiao, Shilin; Zhang, Lu; Bi, Meihua; Zhang, Yunhao; Fang, Jiafei; Hu, Weisheng

    2017-09-01

    A digital chaos-masked optical encryption scheme is proposed and demonstrated. The transmitted signal is completely masked by interference chaotic noise in both bandwidth and amplitude with analog method via dual-drive Mach-Zehnder modulator (DDMZM), making the encrypted signal analog, noise-like and unrecoverable by post-processing techniques. The decryption process requires precise matches of both the amplitude and phase between the cancellation and interference chaotic noises, which provide a large two-dimensional key space with the help of optical interference cancellation technology. For 10-Gb/s 16-quadrature amplitude modulation (QAM) orthogonal frequency division multiplexing (OFDM) signal over the maximum transmission distance of 80 km without dispersion compensation or inline amplifier, the tolerable mismatch ranges of amplitude and phase/delay at the forward error correction (FEC) threshold of 3.8×10-3 are 0.44 dB and 0.08 ns respectively.

  3. A multichannel EEG acquisition scheme based on single ended amplifiers and digital DRL.

    Science.gov (United States)

    Haberman, Marcelo Alejandro; Spinelli, Enrique Mario

    2012-12-01

    Single ended (SE) amplifiers allow implementing biopotential front-ends with a reduced number of parts, being well suited for preamplified electrodes or compact EEG headboxes. On the other hand, given that each channel has independent gain; mismatching between these gains results in poor common-mode rejection ratios (CMRRs) (about 30 dB considering 1% tolerance components). This work proposes a scheme for multichannel EEG acquisition systems based on SE amplifiers and a novel digital driven right leg (DDRL) circuit, which overcome the poor CMRR of the front-end stage providing a high common mode reduction at power line frequency (up to 80 dB). A functional prototype was built and tested showing the feasibility of the proposed technique. It provided EEG records with negligible power line interference, even in very aggressive EMI environments.

  4. A new approach to develop computer-aided detection schemes of digital mammograms

    International Nuclear Information System (INIS)

    Tan, Maxine; Liu, Hong; Zheng, Bin; Qian, Wei; Pu, Jiantao

    2015-01-01

    The purpose of this study is to develop a new global mammographic image feature analysis based computer-aided detection (CAD) scheme and evaluate its performance in detecting positive screening mammography examinations. A dataset that includes images acquired from 1896 full-field digital mammography (FFDM) screening examinations was used in this study. Among them, 812 cases were positive for cancer and 1084 were negative or benign. After segmenting the breast area, a computerized scheme was applied to compute 92 global mammographic tissue density based features on each of four mammograms of the craniocaudal (CC) and mediolateral oblique (MLO) views. After adding three existing popular risk factors (woman’s age, subjectively rated mammographic density, and family breast cancer history) into the initial feature pool, we applied a sequential forward floating selection feature selection algorithm to select relevant features from the bilateral CC and MLO view images separately. The selected CC and MLO view image features were used to train two artificial neural networks (ANNs). The results were then fused by a third ANN to build a two-stage classifier to predict the likelihood of the FFDM screening examination being positive. CAD performance was tested using a ten-fold cross-validation method. The computed area under the receiver operating characteristic curve was AUC = 0.779   ±   0.025 and the odds ratio monotonically increased from 1 to 31.55 as CAD-generated detection scores increased. The study demonstrated that this new global image feature based CAD scheme had a relatively higher discriminatory power to cue the FFDM examinations with high risk of being positive, which may provide a new CAD-cueing method to assist radiologists in reading and interpreting screening mammograms. (paper)

  5. A copyright protection scheme for digital images based on shuffled singular value decomposition and visual cryptography.

    Science.gov (United States)

    Devi, B Pushpa; Singh, Kh Manglem; Roy, Sudipta

    2016-01-01

    This paper proposes a new watermarking algorithm based on the shuffled singular value decomposition and the visual cryptography for copyright protection of digital images. It generates the ownership and identification shares of the image based on visual cryptography. It decomposes the image into low and high frequency sub-bands. The low frequency sub-band is further divided into blocks of same size after shuffling it and then the singular value decomposition is applied to each randomly selected block. Shares are generated by comparing one of the elements in the first column of the left orthogonal matrix with its corresponding element in the right orthogonal matrix of the singular value decomposition of the block of the low frequency sub-band. The experimental results show that the proposed scheme clearly verifies the copyright of the digital images, and is robust to withstand several image processing attacks. Comparison with the other related visual cryptography-based algorithms reveals that the proposed method gives better performance. The proposed method is especially resilient against the rotation attack.

  6. 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-har...

  7. Secure Dynamic access control scheme of PHR in cloud computing.

    Science.gov (United States)

    Chen, Tzer-Shyong; Liu, Chia-Hui; Chen, Tzer-Long; Chen, Chin-Sheng; Bau, Jian-Guo; Lin, Tzu-Ching

    2012-12-01

    With the development of information technology and medical technology, medical information has been developed from traditional paper records into electronic medical records, which have now been widely applied. The new-style medical information exchange system "personal health records (PHR)" is gradually developed. PHR is a kind of health records maintained and recorded by individuals. An ideal personal health record could integrate personal medical information from different sources and provide complete and correct personal health and medical summary through the Internet or portable media under the requirements of security and privacy. A lot of personal health records are being utilized. The patient-centered PHR information exchange system allows the public autonomously maintain and manage personal health records. Such management is convenient for storing, accessing, and sharing personal medical records. With the emergence of Cloud computing, PHR service has been transferred to storing data into Cloud servers that the resources could be flexibly utilized and the operation cost can be reduced. Nevertheless, patients would face privacy problem when storing PHR data into Cloud. Besides, it requires a secure protection scheme to encrypt the medical records of each patient for storing PHR into Cloud server. In the encryption process, it would be a challenge to achieve accurately accessing to medical records and corresponding to flexibility and efficiency. A new PHR access control scheme under Cloud computing environments is proposed in this study. With Lagrange interpolation polynomial to establish a secure and effective PHR information access scheme, it allows to accurately access to PHR with security and is suitable for enormous multi-users. Moreover, this scheme also dynamically supports multi-users in Cloud computing environments with personal privacy and offers legal authorities to access to PHR. From security and effectiveness analyses, the proposed PHR access

  8. Life-critical digital flight control systems

    Science.gov (United States)

    Mcwha, James

    1990-01-01

    Digital autopilot systems were first used on commercial airplanes in the late 1970s. The A-320 airplane was the first air transport airplane with a fly-by-wire primary flight control system. On the 767-X (777) airplane Boeing will install all fly-by-wire flight controls. Activities related to safety, industry status and program phases are discussed.

  9. Turbulent boundary layer under the control of different schemes

    Science.gov (United States)

    Qiao, Z. X.; Zhou, Y.; Wu, Z.

    2017-06-01

    This work explores experimentally the control of a turbulent boundary layer over a flat plate based on wall perturbation generated by piezo-ceramic actuators. Different schemes are investigated, including the feed-forward, the feedback, and the combined feed-forward and feedback strategies, with a view to suppressing the near-wall high-speed events and hence reducing skin friction drag. While the strategies may achieve a local maximum drag reduction slightly less than their counterpart of the open-loop control, the corresponding duty cycles are substantially reduced when compared with that of the open-loop control. The results suggest a good potential to cut down the input energy under these control strategies. The fluctuating velocity, spectra, Taylor microscale and mean energy dissipation are measured across the boundary layer with and without control and, based on the measurements, the flow mechanism behind the control is proposed.

  10. A digital closed loop control system for automatic phase locking of superconducting cavities of IUAC Linac

    International Nuclear Information System (INIS)

    Dutt, R.N.; Rai, A.; Pandey, A.; Sahu, B.K.; Patra, P.; Karmakar, J.; Chaudhari, G.K.; Mathur, Y.; Ghosh, S.; Kanjilal, D.

    2013-01-01

    A closed loop digital control system has been designed and tested to automate the tuning process of superconducting resonators of LINAC at Inter-University Accelerator Centre, New Delhi. The mechanism controls the proportional valves of the He gas based pneumatic tuner in response to the phase and frequency errors of the cavity RF field. The main RF phase lock loop (PLL) is automatically closed once the resonant frequency is within locking range of the resonator PLL. The digital control scheme was successfully tested on few resonators of LINAC cryostat 1. A high stability of phase lock was observed. The details of the digital automation system are presented in the paper. (author)

  11. Prediction-based association control scheme in dense femtocell networks

    Science.gov (United States)

    Pham, Ngoc-Thai; Huynh, Thong; Hwang, Won-Joo; You, Ilsun; Choo, Kim-Kwang Raymond

    2017-01-01

    The deployment of large number of femtocell base stations allows us to extend the coverage and efficiently utilize resources in a low cost manner. However, the small cell size of femtocell networks can result in frequent handovers to the mobile user, and consequently throughput degradation. Thus, in this paper, we propose predictive association control schemes to improve the system’s effective throughput. Our design focuses on reducing handover frequency without impacting on throughput. The proposed schemes determine handover decisions that contribute most to the network throughput and are proper for distributed implementations. The simulation results show significant gains compared with existing methods in terms of handover frequency and network throughput perspective. PMID:28328992

  12. Redundancy scheme for multi-layered accelerator control system

    International Nuclear Information System (INIS)

    Chauhan, Amit; Fatnani, Pravin

    2009-01-01

    The control system for SRS Indus-2 has three-layered architecture. There are VMEbus based stations at the lower two layers that are controlled by their respective CPU board. The 'Profibus' fieldbus standard is used for communication between these VME stations distributed in the field. There is a Profibus controller board at each station to implement the communication protocol. The mode of communication is master-slave (command-response) type. This paper proposes a scheme to implement redundancy at the lower two layers namely Layer-2 (Supervisory Layer / Profibus-master) and Layer-3 (Equipment Unit Interface Layer / Profibus-slave). The redundancy is for both the CPU and the communication board. The scheme uses two CPU boards and two Profi controller boards at each L-3 station. This helps in decreasing any downtime resulting either from CPU faults or communication board faults that are placed in the field area. Redundancy of Profi boards provides two active communication channels between the stations that can be used in different ways thereby increasing the availability on a communication link. Redundancy of CPU boards provides certain level of auto fault-recovery as one CPU remains active and the other CPU remains in standby mode, which takes over the control of VMEbus in case of any fault in the main CPU. (author)

  13. Fragile imperceptible digital watermark with privacy control

    Science.gov (United States)

    Coppersmith, Don; Mintzer, Frederick C.; Tresser, Charles P.; Wu, Chai W.; Yeung, Minerva M.

    1999-04-01

    We propose a watermarking scheme which allows the watermarked image to be authenticated by an authentication agent without revealing to the authentication agent the human-readable content of the image by combining privacy control with watermarking and authentication mechanisms. This watermarking scheme has universal applicability to data sets such as image, video and audio bit streams. The watermark can be made to be imperceptible to humans. Usage of public key cryptography allows the authentication agent to authenticate without the capabilities to watermark an image.

  14. A digital joint controller for manipulators

    International Nuclear Information System (INIS)

    Holt, E.J.; Palmer, D.E.B.

    1993-01-01

    Nuclear Electric's hydraulic heavy duty manipulators are used at a number of Magnox Power Stations for a wide variety of tasks. In recent years there has been a trend towards the use of manipulators for tasks requiring increasing precision of tip positioning. In order to meet this requirement, a digital controller has been designed to replace the analogue controller board used in almost all manipulator control systems. The new controller allows the programming of a wide range of closed loop control algorithms. Position and drive signal data may be passed to and from the controller by digital means, allowing direct connection to a graphical display system and/or a computer executing a guidance algorithm. The hardware and software design are outlined and performance in the laboratory and the field is reported. (author)

  15. Adaptive Tracking Control for Robots With an Interneural Computing Scheme.

    Science.gov (United States)

    Tsai, Feng-Sheng; Hsu, Sheng-Yi; Shih, Mau-Hsiang

    2018-04-01

    Adaptive tracking control of mobile robots requires the ability to follow a trajectory generated by a moving target. The conventional analysis of adaptive tracking uses energy minimization to study the convergence and robustness of the tracking error when the mobile robot follows a desired trajectory. However, in the case that the moving target generates trajectories with uncertainties, a common Lyapunov-like function for energy minimization may be extremely difficult to determine. Here, to solve the adaptive tracking problem with uncertainties, we wish to implement an interneural computing scheme in the design of a mobile robot for behavior-based navigation. The behavior-based navigation adopts an adaptive plan of behavior patterns learning from the uncertainties of the environment. The characteristic feature of the interneural computing scheme is the use of neural path pruning with rewards and punishment interacting with the environment. On this basis, the mobile robot can be exploited to change its coupling weights in paths of neural connections systematically, which can then inhibit or enhance the effect of flow elimination in the dynamics of the evolutionary neural network. Such dynamical flow translation ultimately leads to robust sensory-to-motor transformations adapting to the uncertainties of the environment. A simulation result shows that the mobile robot with the interneural computing scheme can perform fault-tolerant behavior of tracking by maintaining suitable behavior patterns at high frequency levels.

  16. Planning Framework for Mesolevel Optimization of Urban Runoff Control Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Qianqian; Blohm, Andrew; Liu, Bo

    2017-04-01

    A planning framework is developed to optimize runoff control schemes at scales relevant for regional planning at an early stage. The framework employs less sophisticated modeling approaches to allow a practical application in developing regions with limited data sources and computing capability. The methodology contains three interrelated modules: (1)the geographic information system (GIS)-based hydrological module, which aims at assessing local hydrological constraints and potential for runoff control according to regional land-use descriptions; (2)the grading module, which is built upon the method of fuzzy comprehensive evaluation. It is used to establish a priority ranking system to assist the allocation of runoff control targets at the subdivision level; and (3)the genetic algorithm-based optimization module, which is included to derive Pareto-based optimal solutions for mesolevel allocation with multiple competing objectives. The optimization approach describes the trade-off between different allocation plans and simultaneously ensures that all allocation schemes satisfy the minimum requirement on runoff control. Our results highlight the importance of considering the mesolevel allocation strategy in addition to measures at macrolevels and microlevels in urban runoff management. (C) 2016 American Society of Civil Engineers.

  17. Study on noise prediction model and control schemes for substation.

    Science.gov (United States)

    Chen, Chuanmin; Gao, Yang; Liu, Songtao

    2014-01-01

    With the government's emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation's acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation's design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods.

  18. Study on Noise Prediction Model and Control Schemes for Substation

    Science.gov (United States)

    Gao, Yang; Liu, Songtao

    2014-01-01

    With the government's emphasis on environmental issues of power transmission and transformation project, noise pollution has become a prominent problem now. The noise from the working transformer, reactor, and other electrical equipment in the substation will bring negative effect to the ambient environment. This paper focuses on using acoustic software for the simulation and calculation method to control substation noise. According to the characteristics of the substation noise and the techniques of noise reduction, a substation's acoustic field model was established with the SoundPLAN software to predict the scope of substation noise. On this basis, 4 reasonable noise control schemes were advanced to provide some helpful references for noise control during the new substation's design and construction process. And the feasibility and application effect of these control schemes can be verified by using the method of simulation modeling. The simulation results show that the substation always has the problem of excessive noise at boundary under the conventional measures. The excess noise can be efficiently reduced by taking the corresponding noise reduction methods. PMID:24672356

  19. More efficient purifying scheme via controlled-controlled NOT gate

    International Nuclear Information System (INIS)

    Metwally, N.; Obada, A.-S.

    2006-01-01

    A new modified version of the Oxford purification protocol is proposed. This version is based on the controlled-controlled NOT gate instead of controlled NOT in the original one. Comparisons between the results of the new version and the original and an earlier modification are given. It is found that the new version converges faster and consumes fewer initial qubit pairs of low fidelity per final qubit pair of high fidelity

  20. Digital control of electric drives

    CERN Document Server

    Koziol, R; Szklarski, L

    1992-01-01

    The electromechanical systems employed in different branches of industry are utilized most often as drives of working machines which must be fed with electric energy in a continuous, periodic or even discrete way. Some of these machines operate at constant speed, others require wide and varying energy control. In many designs the synchronous cooperation of several electric drives is required in addition to the desired dynamic properties. For these reasons the control of the cooperation and dynamics of electromechanical systems requires the use of computers.This book adopts an unusual approach

  1. Error control coding schemes in digital systems | Kwaha | Global ...

    African Journals Online (AJOL)

    The rare opportunity given by the unprecedented spatial and temporal coverage of POGO satellites data is exploited to present all possible cross sections of equatorial electrojet (EEJ) current in the group of papers. Here the all-longitude means at 7 hours centred on local noon and the daytime means at 36 longitudes, of the ...

  2. Error control coding schemes in digital systems | Kwaha | Global ...

    African Journals Online (AJOL)

    ... rockets data and from POGO Satellites data are not significantly different and that (d) It is essential to take into account the lack of symmetry between the vertical distributions of EEJ current density below and above the altitude of EEJ peak current density. (Global Journal of Pure and Applied Sciences: 2002 8(3): 381-388) ...

  3. Error control coding schemes in digital systems | Kwaha | Global ...

    African Journals Online (AJOL)

    If you would like more information about how to print, save, and work with PDFs, Highwire Press provides a helpful Frequently Asked Questions about PDFs. Alternatively, you can download the PDF file directly to your computer, from where it can be opened using a PDF reader. To download the PDF, click the Download link ...

  4. Two nonlinear control schemes contrasted on a hydrodynamiclike model

    Science.gov (United States)

    Keefe, Laurence R.

    1993-01-01

    The principles of two flow control strategies, those of Huebler (Luescher and Huebler, 1989) and of Ott et al. (1990) are discussed, and the two schemes are compared for their ability to control shear flow, using fully developed and transitional solutions of the Ginzburg-Landau equation as models for such flows. It was found that the effectiveness of both methods in obtaining control of fully developed flows depended strongly on the 'distance' in state space between the uncontrolled flow and goal dynamics. There were conceptual difficulties in applying the Ott et al. method to transitional convectively unstable flows. On the other hand, the Huebler method worked well, within certain limitations, although at a large cost in energy terms.

  5. Two-stage Keypoint Detection Scheme for Region Duplication Forgery Detection in Digital Images.

    Science.gov (United States)

    Emam, Mahmoud; Han, Qi; Zhang, Hongli

    2018-01-01

    In digital image forensics, copy-move or region duplication forgery detection became a vital research topic recently. Most of the existing keypoint-based forgery detection methods fail to detect the forgery in the smooth regions, rather than its sensitivity to geometric changes. To solve these problems and detect points which cover all the regions, we proposed two steps for keypoint detection. First, we employed the scale-invariant feature operator to detect the spatially distributed keypoints from the textured regions. Second, the keypoints from the missing regions are detected using Harris corner detector with nonmaximal suppression to evenly distribute the detected keypoints. To improve the matching performance, local feature points are described using Multi-support Region Order-based Gradient Histogram descriptor. Based on precision-recall rates and commonly tested dataset, comprehensive performance evaluation is performed. The results demonstrated that the proposed scheme has better detection and robustness against some geometric transformation attacks compared with state-of-the-art methods. © 2017 American Academy of Forensic Sciences.

  6. Improving the Authentication Scheme and Access Control Protocol for VANETs

    Directory of Open Access Journals (Sweden)

    Wei-Chen Wu

    2014-11-01

    Full Text Available Privacy and security are very important in vehicular ad hoc networks (VANETs. VANETs are negatively affected by any malicious user’s behaviors, such as bogus information and replay attacks on the disseminated messages. Among various security threats, privacy preservation is one of the new challenges of protecting users’ private information. Existing authentication protocols to secure VANETs raise challenges, such as certificate distribution and reduction of the strong reliance on tamper-proof devices. In 2011, Yeh et al. proposed a PAACP: a portable privacy-preserving authentication and access control protocol in vehicular ad hoc networks. However, PAACP in the authorization phase is breakable and cannot maintain privacy in VANETs. In this paper, we present a cryptanalysis of an attachable blind signature and demonstrate that the PAACP’s authorized credential (AC is not secure and private, even if the AC is secretly stored in a tamper-proof device. An eavesdropper can construct an AC from an intercepted blind document. Any eavesdropper can determine who has which access privileges to access which service. For this reason, this paper copes with these challenges and proposes an efficient scheme. We conclude that an improving authentication scheme and access control protocol for VANETs not only resolves the problems that have appeared, but also is more secure and efficient.

  7. Distributed digital control of accelerators

    International Nuclear Information System (INIS)

    Crowley-Milling, M.

    1984-01-01

    The special properties, requirements and limitations of distributed control systems are described. The main advantages of distributed over centralized systems can be summarized: (a) For geographically distributed systems, complete systems can be operated locally even when links to the centre and the central system are unavailable. Similarly, parts of the equipment can be tested and commissioned separately during the constructon period; (b) Distribution of tasks between a number of computers gives the possibility of parallel processing with a corresponding gain in speed and reduction in response time; (c) Computer configurations and operating systems can be tailored to suit the application. New requirements can be catered for by the addition of one or more computers to the network without disturbance of the existing system; (d) Local surveillance and testing can reduce the load at higher levels which only need to be informed if anything goes wrong. Diagnosis of faults can be easier, despite the increase in number of units, as they can be arranged to test each other. Maintenance can be easier in a modular system, by exchange of modules, and it is easier to provide redundancy in vital parts of the system; (e) Different groups can work on different parts of the system with the minimum of interference; (f) The needs for bandwidth in the communications system for a large machine are lower for a decentralized than for a centralizzed system; (g) A distributed system can have economic advantages. It may require more hardware, which is becoming cheaper, but the software, which, if anything, is becoming more expensive, is generally simpler, and replicated

  8. Estimation of multiply digital process control system extractive distillation stability

    Directory of Open Access Journals (Sweden)

    V. S. Kudryashov

    2016-01-01

    Full Text Available An approach to stability analysis of digital control systems associated non-stationary object on the example of the rectification process. Object modeling with cross-connections and the control scheme of the described system, discrete transfer functions in the shift operators. The equations of connection for each output of the closed-loop system. To solve this problem developed an algorithm for estimating the margin of stability of multivariable digital control systems based on the discrete root criterion, comprising the following main stages: obtaining of the characteristic polynomial of the closed-loop system for each output; computation of eigenvalues of the system matrix in the state space to determine roots of the characteristic equation and the stability of the system; determination of the stability and margin of stability by the deviation of maximum module of the root from the boundary of the high variability. To obtain the characteristic polynomial of a as discrete models of controllers and channels of IP object-use the transfer function of the first order with transport delay. The simulation was performed at different parameters of the control object, which is characterized by a stable and an unstable state of the system. VA-den analysis of the numerical values of the roots and character of their location on the complex plane, which to you-water that the system is stable or unstable. To confirm the obtained results were calculated and presented dynamic characteristics of the closed-loop system under different conditions, which confirm the initial assessment, the root criterion. To determine the factor stability of multivariable digital systems is proposed to use the deviation of the maximum root of the characteristic equation from the stability boundary. The obtained results apply to the class of symmetric multivariable control objects. The approach to assessing the sustainability of multivariable system regulation can be effectively

  9. Algorithms for Optimal Model Distributions in Adaptive Switching Control Schemes

    Directory of Open Access Journals (Sweden)

    Debarghya Ghosh

    2016-03-01

    Full Text Available Several multiple model adaptive control architectures have been proposed in the literature. Despite many advances in theory, the crucial question of how to synthesize the pairs model/controller in a structurally optimal way is to a large extent not addressed. In particular, it is not clear how to place the pairs model/controller is such a way that the properties of the switching algorithm (e.g., number of switches, learning transient, final performance are optimal with respect to some criteria. In this work, we focus on the so-called multi-model unfalsified adaptive supervisory switching control (MUASSC scheme; we define a suitable structural optimality criterion and develop algorithms for synthesizing the pairs model/controller in such a way that they are optimal with respect to the structural optimality criterion we defined. The peculiarity of the proposed optimality criterion and algorithms is that the optimization is carried out so as to optimize the entire behavior of the adaptive algorithm, i.e., both the learning transient and the steady-state response. A comparison is made with respect to the model distribution of the robust multiple model adaptive control (RMMAC, where the optimization considers only the steady-state ideal response and neglects any learning transient.

  10. Distributed and recoverable digital control system

    Science.gov (United States)

    Stange, Kent (Inventor); Hess, Richard (Inventor); Kelley, Gerald B (Inventor); Rogers, Randy (Inventor)

    2010-01-01

    A real-time multi-tasking digital control system with rapid recovery capability is disclosed. The control system includes a plurality of computing units comprising a plurality of redundant processing units, with each of the processing units configured to generate one or more redundant control commands. One or more internal monitors are employed for detecting data errors in the control commands. One or more recovery triggers are provided for initiating rapid recovery of a processing unit if data errors are detected. The control system also includes a plurality of actuator control units each in operative communication with the computing units. The actuator control units are configured to initiate a rapid recovery if data errors are detected in one or more of the processing units. A plurality of smart actuators communicates with the actuator control units, and a plurality of redundant sensors communicates with the computing units.

  11. Digital repetitive control under varying frequency conditions

    CERN Document Server

    Ramos, Germán A; Olm, Josep M

    2013-01-01

    The tracking/rejection of periodic signals constitutes a wide field of research in the control theory and applications area. Repetitive Control has proven to be an efficient way to face this topic. However, in some applications the frequency of the reference/disturbance signal is time-varying or uncertain. This causes an important performance degradation in the standard Repetitive Control scheme. This book presents some solutions to apply Repetitive Control in varying frequency conditions without loosing steady-state performance. It also includes a complete theoretical development and experimental results in two representative systems. The presented solutions are organized in two complementary branches: varying sampling period Repetitive Control and High Order Repetitive Control. The first approach allows dealing with large range frequency variations while the second allows dealing with small range frequency variations. The book also presents applications of the described techniques to a Roto-magnet plant and...

  12. A chaos-based digital image encryption scheme with an improved diffusion strategy.

    Science.gov (United States)

    Fu, Chong; Chen, Jun-jie; Zou, Hao; Meng, Wei-hong; Zhan, Yong-feng; Yu, Ya-wen

    2012-01-30

    Chaos-based image cipher has been widely investigated over the last decade or so to meet the increasing demand for real-time secure image transmission over public networks. In this paper, an improved diffusion strategy is proposed to promote the efficiency of the most widely investigated permutation-diffusion type image cipher. By using the novel bidirectional diffusion strategy, the spreading process is significantly accelerated and hence the same level of security can be achieved with fewer overall encryption rounds. Moreover, to further enhance the security of the cryptosystem, a plain-text related chaotic orbit turbulence mechanism is introduced in diffusion procedure by perturbing the control parameter of the employed chaotic system according to the cipher-pixel. Extensive cryptanalysis has been performed on the proposed scheme using differential analysis, key space analysis, various statistical analyses and key sensitivity analysis. Results of our analyses indicate that the new scheme has a satisfactory security level with a low computational complexity, which renders it a good candidate for real-time secure image transmission applications.

  13. Stability of digital feedback control systems

    Directory of Open Access Journals (Sweden)

    Larkin Eugene

    2018-01-01

    Lag time characteristics are used for investigation of stability of linear systems. Digital PID controller is divided onto linear part, which is realized with a soft and pure lag unit, which is realized with both hardware and software. With use notions amplitude and phase margins, condition for stability of system functioning are obtained. Theoretical results are confirm with computer experiment carried out on the third-order system.

  14. Technical quality control - constancy controls for digital mammography systems

    International Nuclear Information System (INIS)

    Pedersen, K.; Landmark, I.D.; Bredholt, K.; Hauge, I.H.R.

    2009-04-01

    To ensure the quality of mammographic images, so-called constancy control tests are performed frequently. The report contains a programme for constancy control of digital mammography systems, encompassing the mammography unit, computed radiography (CR) systems, viewing conditions and displays, printers, and procedures for data collection for patient dose calculations. (Author)

  15. Digital computer control of servomotor angular position | Mullisa ...

    African Journals Online (AJOL)

    The paper discussess the design and simulation methodology of digital control systems for the benefit of the interested practicing engineer. A lead-type digital controller for a 2nd order system and a leadlag type digital controller for a 3rd order system are designed. The simulations show that the design methods are ...

  16. High Performance Low Cost Digitally Controlled Power Conversion Technology

    DEFF Research Database (Denmark)

    Jakobsen, Lars Tønnes

    2008-01-01

    Digital control of switch-mode power supplies and converters has within the last decade evolved from being an academic subject to an emerging market in the power electronics industry. This development has been pushed mainly by the computer industry that is looking towards digital power management...... the execution time of the software algorithm that realises the digital control law will constitute a considerable delay in the control loop. Digital signal controllers are powerful devices capable of performing arithmetic functions much faster than a microcontroller can. Digital signal controllers are well...... and an analogue to digital converter with a short sampling time. A digital self-oscillating modulator is proposed in the present thesis. The modulator is a free-running modulator which operates without an external carrier signal. Customised digital control solutions offers the best performance for non-isolated DC...

  17. Proposition of a scheme for adaptive/intelligent analog-to-digital converters

    International Nuclear Information System (INIS)

    Vaidya, P.P.; Kataria, S.K.

    2001-01-01

    The paper proposes design of a new class of Analog to Digital Converters (ADC's) which we call as Intelligent ADC's with moving resolution. Unlike presently available ADC's which are designed for specific range of applications and give fixed resolution and conversion time, the intelligent ADC's described here can adjust their resolution during the process of conversion, depending upon nature of input signal to make optimum use of the hard-ware. It is possible to use an intelligent ADC to give resolution ranging from 8 bit to 16 bit and conversion time ranging from few nano sec. to few micro secs. These ADC's have significant advantages over conventional ones when used for nuclear pulse spectroscopy as well as for process control applications. (author)

  18. Comparison and Analysis of the Control Power Between Two Different Perfect Controlled Teleportation Schemes Using Four-particle Cluster State

    Science.gov (United States)

    Jiang, Yu-ting; Mo, Zhi-wen

    2017-10-01

    Control power is used to discuss about the controller's measurable authority. It's a new index to describe the controlled teleportation schemes from the point of view of the controller. In this paper, we introduce two perfect controlled teleportation schemes and calculate the control power under different control particles. In scheme 1, the controller just controls one particle, which is particle 2. And in scheme 2, the controller controls the particles 2 and 3. They both use the cluster state |ψ > _{1234}={1/2}(|0000> +|0011> +|1100> -|1111> )_{1234} as communication channel. By calculating the control power between two schemes, the control power of scheme 1 is 1/3, which is the minimal value of control power. On the contrary, the control power of scheme 2 is maximal, 1/2. Scheme 2 which controls two particles successfully promotes the control power comparing with scheme 1. It's evidently that controlling particle 2 is a necessary condition. And controlling particle 3 can gain the control power but the controller cannot control it solely.

  19. Experimental Study on Intelligent Control Scheme for Fan Coil Air-Conditioning System

    Directory of Open Access Journals (Sweden)

    Yanfeng Li

    2013-01-01

    Full Text Available An intelligent control scheme for fan coil air-conditioning systems has been put forward in order to overcome the shortcomings of the traditional proportion-integral-derivative (PID control scheme. These shortcomings include the inability of anti-interference and large inertia. An intelligent control test rig of fan coil air-conditioning system has been built, and MATLAB/Simulink dynamics simulation software has been adopted to implement the intelligent control scheme. A software for data exchange has been developed to combine the intelligence control system and the building automation (BA system. Experimental tests have been conducted to investigate the effectiveness of different control schemes including the traditional PID control, fuzzy control, and fuzzy-PID control for fan coil air-conditioning system. The effects of control schemes have been compared and analyzed in robustness, static and dynamic character, and economy. The results have shown that the developed data exchange interface software can induce the intelligent control scheme of the BA system more effectively. Among the proposed control strategies, fuzzy-PID control scheme which has the advantages of both traditional PID and fuzzy schemes is the optimal control scheme for the fan coil air-conditioning system.

  20. Sensor scheme design for active structural acoustic control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    Efficient sensing schemes for the active reduction of sound radiation from plates are presented based on error signals derived from spatially weighted plate velocity or near-field pressure. The schemes result in near-optimal reductions as compared to weighting procedures derived from eigenvector or

  1. DIGITAL WATERMARKING SCHEMES FOR AUTHORIZATION AGAINST COPYING OR PIRACY OF COLOR IMAGES

    OpenAIRE

    Dheerendra S Tomar; Keshav S Rawat,

    2010-01-01

    This paper presents digital watermarking methods for authorization against copying or piracy of color images. Watermarking is a very important field for copyrights of various electronic documents and media. With images widely available on the Internet, it may sometimes be desirable to use watermarks. Digital watermarking is the processing of combined information into a digital signal. A watermark is a secondary image, which is overlaid on the host image, and provides a means of protecting the...

  2. Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices

    Energy Technology Data Exchange (ETDEWEB)

    McEntee, Jarlath [Ocean Renewable Power Company, Portland, ME (United States); Polagye, Brian [Ocean Renewable Power Company, Portland, ME (United States); Fabien, Brian [Ocean Renewable Power Company, Portland, ME (United States); Thomson, Jim [Ocean Renewable Power Company, Portland, ME (United States); Kilcher, Levi [Ocean Renewable Power Company, Portland, ME (United States); Marnagh, Cian [Ocean Renewable Power Company, Portland, ME (United States); Donegan, James [Ocean Renewable Power Company, Portland, ME (United States)

    2016-03-31

    The Advanced Energy Harvesting Control Schemes for Marine Renewable Energy Devices (Project) investigated, analyzed and modeled advanced turbine control schemes with the objective of increasing the energy harvested by hydrokinetic turbines in turbulent flow. Ocean Renewable Power Company (ORPC) implemented and validated a feedforward controller to increase power capture; and applied and tested the controls on ORPC’s RivGen® Power Systems in Igiugig, Alaska. Assessments of performance improvements were made for the RivGen® in the Igiugig environment and for ORPC’s TidGen® Power System in a reference tidal environment. Annualized Energy Production (AEP) and Levelized Cost of Energy (LCOE) improvements associated with implementation of the recommended control methodology were made for the TidGen® Power System in the DOE reference tidal environment. System Performance Advancement (SPA) goals were selected for the project. SPA targets were to improve Power to Weight Ratio (PWR) and system Availability, with the intention of reducing Levelized Cost of Electricity (LCOE). This project focused primarily reducing in PWR. Reductions in PWR of 25.5% were achieved. Reductions of 20.3% in LCOE were achieved. This project evaluated four types of controllers which were tested in simulation, emulation, a laboratory flume, and the field. The adaptive Kω2 controller performs similarly to the non-adaptive version of the same controller and may be useful in tidal channels where the mean velocity is continually evolving. Trends in simulation were largely verified through experiments, which also provided the opportunity to test assumptions about turbine responsiveness and control resilience to varying scales of turbulence. Laboratory experiments provided an essential stepping stone between simulation and implementation on a field-scale turbine. Experiments also demonstrated that using “energy loss” as a metric to differentiate between well-designed controllers operating at

  3. Hardware for digitally controlled scanned probe microscopes

    OpenAIRE

    Clark, S. M.; Baselt, D. R.; Spence, C. F.; Youngquist, M. G.; Baldeschwieler, J. D.

    1992-01-01

    The design and implementation of a flexible and modular digital control and data acquisition system for scanned probe microscopes (SPMs) is presented. The measured performance of the system shows it to be capable of 14-bit data acquisition at a 100-kHz rate and a full 18-bit output resolution resulting in less than 0.02-Å rms position noise while maintaining a scan range in excess of 1 µm in both the X and Y dimensions. This level of performance achieves the goal of making the noise of the mi...

  4. 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...

  5. Digital signal processing in power electronics control circuits

    CERN Document Server

    Sozanski, Krzysztof

    2013-01-01

    Many digital control circuits in current literature are described using analog transmittance. This may not always be acceptable, especially if the sampling frequency and power transistor switching frequencies are close to the band of interest. Therefore, a digital circuit is considered as a digital controller rather than an analog circuit. This helps to avoid errors and instability in high frequency components. Digital Signal Processing in Power Electronics Control Circuits covers problems concerning the design and realization of digital control algorithms for power electronics circuits using

  6. CANDU Digital Control Computer upgrade options

    International Nuclear Information System (INIS)

    De Jong, M.S.; De Grosbois, J.; Qian, T.

    1997-01-01

    This paper reviews the evolution of Digital Control Computers (DCC) in CANDU power plants to the present day. Much of this evolution has been to meeting changing control or display requirements as well as the replacement of obsolete, or old and less reliable technology with better equipment that is now available. The current work at AECL and Canadian utilities to investigate DCC upgrade options, alternatives, and strategies are examined. The dependence of a particular upgrade strategy on the overall plant refurbishment plans are also discussed. Presently, the upgrade options range from replacement of individual obsolete system components, to replacement of the entire DCC hardware without changing the software, to complete replacement of the DCCs with a functionally equivalent system using new control computer equipment and software. Key issues, constraints and objectives associated with these DCC upgrade options are highlighted. (author)

  7. Lessons learned in digital upgrade projects digital control system implementation at US nuclear power stations

    International Nuclear Information System (INIS)

    Kelley, S.; Bolian, T. W.

    2006-01-01

    AREVA NP has gained significant experience during the past five years in digital upgrades at operating nuclear power stations in the US. Plants are seeking modernization with digital technology to address obsolescence, spare parts availability, vendor support, increasing age-related failures and diminished reliability. New systems offer improved reliability and functionality, and decreased maintenance requirements. Significant lessons learned have been identified relating to the areas of licensing, equipment qualification, software quality assurance and other topics specific to digital controls. Digital control systems have been installed in non safety-related control applications at many utilities within the last 15 years. There have also been a few replacements of small safety-related systems with digital technology. Digital control systems are proving to be reliable, accurate, and easy to maintain. Digital technology is gaining acceptance and momentum with both utilities and regulatory agencies based upon the successes of these installations. Also, new plants are being designed with integrated digital control systems. To support plant life extension and address obsolescence of critical components, utilities are beginning to install digital technology for primary safety-system replacement. AREVA NP analyzed operating experience and lessons learned from its own digital upgrade projects as well as industry-wide experience to identify key issues that should be considered when implementing digital controls in nuclear power stations

  8. Automated Categorization Scheme for Digital Libraries in Distance Learning: A Pattern Recognition Approach

    Science.gov (United States)

    Gunal, Serkan

    2008-01-01

    Digital libraries play a crucial role in distance learning. Nowadays, they are one of the fundamental information sources for the students enrolled in this learning system. These libraries contain huge amount of instructional data (text, audio and video) offered by the distance learning program. Organization of the digital libraries is…

  9. Acting, playing, or talking about the story: an annotation scheme for communication during interactive digital storytelling

    NARCIS (Netherlands)

    Theune, Mariet; Linssen, Johannes Maria; Alofs, Thijs

    2013-01-01

    In this paper we investigate the communication of children playing with an interactive digital storytelling system. What users say during their interaction with a digital storytelling system can tell us much about how they relate to the characters and how engrossed they are in the storytelling

  10. Analysis and improvement of digital control stability for master-slave manipulator system

    International Nuclear Information System (INIS)

    Yoshida, Koichi; Yabuta, Tetsuro

    1992-01-01

    Some bilateral controls of master-slave system have been designed, which can realize high-fidelity telemanipulation as if the operator were manipulating the object directly. While usual robot systems are controlled by software-servo system using digital computer, little work has been published on design and analysis for digital control of these systems, which must consider time-delay of sensor signals and zero order hold effect of command signals on actuators. This paper presents a digital control analysis for single degree of freedom master-slave system including impedance models of both the human operator and the task object, which clarifies some index for the stability. The stability result shows a virtual master-slave system concepts, which improve the digital control stability. We first analyze a dynamic control method of master-slave system in discrete-time system for the stability problem, which can realize high-fidelity telemanipulation in the continuous-time. Secondly, using the results of the stability analysis, the robust control scheme for master-slave system is proposed, and the validity of this scheme is finally confirmed by the simulation. Consequently, it would be considered that any combination of master and slave modules with dynamic model of these manipulators is possible to construct the stable master-slave system. (author)

  11. Low cost highly available digital control computer

    International Nuclear Information System (INIS)

    Silvers, M.W.

    1986-01-01

    When designing digital controllers for critical plant control it is important to provide several features. Among these are reliability, availability, maintainability, environmental protection, and low cost. An examination of several applications has lead to a design that can be produced for approximately $20,000 (1000 control points). This design is compatible with modern concepts in distributed and hierarchical control. The canonical controller element is a dual-redundant self-checking computer that communicates with a cross-strapped, electrically isolated input/output system. The input/output subsystem comprises multiple intelligent input/output cards. These cards accept commands from the primary processor which are validated, executed, and acknowledged. Each card may be hot replaced to facilitate sparing. The implementation of the dual-redundant computer architecture is discussed. Called the FS-86, this computer can be used for a variety of applications. It has most recently found application in the upgrade of San Francisco's Bay Area Rapid Transit (BART) train control currently in progress and has been proposed for feedwater control in a boiling water reactor

  12. A Study of Digitally Controlled Flight Control Actuation

    Science.gov (United States)

    1983-07-01

    in 12 groups of three. CONTROL SERVO PROCESSOR PROCESSOR EhSV ACT.• ~INTERNAL , A Wm1R INC A, CHANNEL A1-12 MIL-STD-1553 B BUS A A C1.12 j CHANNEL 11...line operation in channels where applicable) a Servo modeling and comparison to actual electrohydraulic servovalve ( EHSV ) e Control n transmission and...AFWAL-TR-83-3041 A A STUDY OF DIGITALLY CONTROLLED FLIGHT CONTROL ACTUATION HOWARD H. BELMONT HR TEXTRON INC. 25200 WEST RYE CANYON ROAD VALENCIA

  13. Digitization and simulation realization of full range control system for steam generator water level

    International Nuclear Information System (INIS)

    Qian Hong; Ye Jianhua; Qian Fei; Li Chao

    2010-01-01

    In this paper, a full range digital control system for the steam generator water level is designed by a control scheme of single element control and three-element cascade feed-forward control, and the method to use the software module configuration is proposed to realize the water level control strategy. This control strategy is then applied in the operation of the nuclear power simulation machine. The simulation result curves indicate that the steam generator water level maintains constant at the stable operation condition, and when the load changes, the water level changes but finally maintains the constant. (authors)

  14. Experience of digital control systems in Scandinavian BWRs

    International Nuclear Information System (INIS)

    Rydahl, I.

    1989-01-01

    Since 1984 digital control systems have been in operation in various Scandinavian BWRs. Examples of such digital control systems are: dual microprocessor based system for complete control of radwaste plant, three channel recirculation control system, and three channel feedwater control system. This paper describes Swedish development from one channel through three channel analog control systems to digital systems. The author describes experience of digital control systems during design, testing, commissioning and operation. The main benefits of digital compared with analog technology are discussed. Especially the outstanding facility of using a built-in process simulator for commissioning and tuning. The use of digital technology in nuclear safety system and future plans are dealt with

  15. Using the digital reactor control systems at NPP

    International Nuclear Information System (INIS)

    Schirl, G.; Hertel, J.

    2006-01-01

    A conception of application of the digital reactor control systems (RCS) at NPP is presented. The digital RCS architecture and safety ensuring are considered. The strategy and algorithm of the operating NPP equipping with the new digital RCS are given too [ru

  16. Double Modulation Scheme for Switching Mixers Controlled by Sigma-Delta Modulators

    DEFF Research Database (Denmark)

    Nielsen, Per Asbeck; Fallesen, Carsten

    1998-01-01

    . This modification can be carried out on a large variety of mixers including the above mentioned. Although the principle was meant to be used to down convert analog signals, the principle is general and can be used in digital circuits too. This paper verifies the new mixing scheme and compares it to the traditional...

  17. Design, implementation and analysis of fully digital 1-D controllable multiscroll chaos

    KAUST Repository

    Mansingka, Abhinav S.

    2011-12-01

    This paper introduces the fully digital implementation of a 1-D multiscroll chaos generator based on a staircase nonlinearity in the 3rd-order jerk system using the Euler approximation. For the first time, digital design is exploited to provide real-time controllability of (i) number of scrolls, (ii) position in 1-D space, (iii) Euler step size and (iv) system parameter. The effect of variations in these fields on the maximum Lyapunov exponent (MLE) is analyzed. The system is implemented using Verilog HDL and synthesized on an Xilinx Virtex 4 FPGA, exhibiting area utilization less than 3.5% and high performance with experimentally verified throughput up to 3.33 Gbits/s. This fully digital system enables applications in modulation schemes and chaos-based cryptosystems without analog to digital conversion. © 2011 IEEE.

  18. Emulation-based comparative study of centralized and distributed control schemes for optical networks

    Science.gov (United States)

    Xin, Chunsheng; Ye, Yinghua; Dixit, Sudhir; Qiao, Chunming

    2001-07-01

    Recently there are considerable amount of research about the automatic control and provisioning in all optical networks. One of the critical issues is how to provide effective lightpath provisioning to improve network performance, such as blocking probability and decision time. Depending on the network topology, configuration, and administration policy, a distributed or centralized control scheme can be employed to manage the routing and signaling. In a distributed control scheme, each node exchanges information with other nodes, but performs routing and signaling independently from other nodes. On the other hand, in a centralized scheme, each node communicates with a central controller and the controller performs routing and signaling on behalf of all other nodes. Intuitively, the centralized scheme can obtain a lower blocking probability since the controller has the complete resource availability information. We have studied the two schemes through emulations, determined the signaling and processing overheads and quantified the conditions that favor one approach over the other.

  19. Hybrid Data Hiding Scheme Using Right-Most Digit Replacement and Adaptive Least Significant Bit for Digital Images

    Directory of Open Access Journals (Sweden)

    Mehdi Hussain

    2016-05-01

    Full Text Available The goal of image steganographic methods considers three main key issues: high embedding capacity, good visual symmetry/quality, and security. In this paper, a hybrid data hiding method combining the right-most digit replacement (RMDR with an adaptive least significant bit (ALSB is proposed to provide not only high embedding capacity but also maintain a good visual symmetry. The cover-image is divided into lower texture (symmetry patterns and higher texture (asymmetry patterns areas and these textures determine the selection of RMDR and ALSB methods, respectively, according to pixel symmetry. This paper has three major contributions. First, the proposed hybrid method enhanced the embedding capacity due to efficient ALSB utilization in the higher texture areas of cover images. Second, the proposed hybrid method maintains the high visual quality because RMDR has the closest selection process to generate the symmetry between stego and cover pixels. Finally, the proposed hybrid method is secure against statistical regular or singular (RS steganalysis and pixel difference histogram steganalysis because RMDR is capable of evading the risk of RS detection attacks due to pixel digits replacement instead of bits. Extensive experimental tests (over 1500+ cover images are conducted with recent least significant bit (LSB-based hybrid methods and it is demonstrated that the proposed hybrid method has a high embedding capacity (800,019 bits while maintaining good visual symmetry (39.00% peak signal-to-noise ratio (PSNR.

  20. Digital Single-Phase Power-Factor Controller

    Science.gov (United States)

    Dabney, R. W.

    1983-01-01

    Digital circuit has faster response to load changes. Digital power-factor controller senses changing motor-load torques by sampling open-circuit voltage across gate-controlled silicon switch. Circuit responds more rapidly to hanging loads than analog power-factor controllers because no low-pass filter is in feedback loop.

  1. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    Electrical stimulation has been used in a wide variety of medical implant applications. In all of these applications, due to safety concerns, maintaining charge balance becomes a critically important issue that needs to be addressed at the design stage. It is important that charge balancing schemes be robust to circuit ...

  2. A simple output voltage control scheme for single phase wavelet ...

    African Journals Online (AJOL)

    DR OKE

    Wavelet based techniques have been extensively used in various power engineering applications. Recently, wavelet has also been proposed to generate switching signal for single-phase pulse-width-modulated (PWM) dc-ac inverter. The main advantage of the wavelet modulated (WM) scheme is that a single synthesis ...

  3. PI controller scheme for charge balance in implantable electrical ...

    Indian Academy of Sciences (India)

    Another approach, the offset regulation scheme [2], moni- tors the residual voltage and uses a discrete set of current sources to incrementally change the anodic phase ..... It can be seen from the graph of figure 14, that a trade-off exists amongst the overshoot, settling time, steady state out- put error and values of Kp and Ki.

  4. Performance evaluation of time-delay control schemes for uninterruptible power supplies

    DEFF Research Database (Denmark)

    Loh, P.C; Tang, Y.; Blaabjerg, Frede

    2008-01-01

    transitions. Even more favorable is that the above-described performance features are attained under all load-operating conditions and at the same level of implementation easiness as for the traditional double-loop control scheme. Lastly, for verifying the practicality of the control schemes, an experimental...

  5. Digital holography for coherent fiber beam combining with a co-propagative scheme.

    Science.gov (United States)

    Antier, Marie; Larat, Christian; Lallier, Eric; Bourderionnet, Jérôme; Primot, Jérôme; Brignon, Arnaud

    2014-09-22

    We present a technique for passive coherent fiber beam combining based on digital holography. In this method, the phase errors between the fibers are compensated by the diffracted phase-conjugated -1 order of a digital hologram. Unlike previous digital holography technique, the probe beams measuring the phase errors between the fibers are co-propagating with the phase-locked signal beams. This architecture is compatible with the use of multi-stage isolated amplifying fibers. It does not require any phase calculation algorithm and its correction is collective. This concept is experimentally demonstrated with three fibers at 1.55 μm. A residual phase error of λ/20 is measured.

  6. Rolls-Royce digital Rod Control System

    International Nuclear Information System (INIS)

    Pouillot, M.

    2010-01-01

    Full text of publication follows: Rolls-Royce has developed a new generation of Rod Control System, based on 40 years of experience. The fifth-generation Rod Control System (RCS) from Rolls-Royce offers a reliable, modular design with adaptability to your preferred platform, for modernization projects or new reactors. Flexible implementation provides the option for you to keep existing cabinets, which permits you to optimize installation approach. Main features for the power part: - Control Rod Drive Mechanism (CRDM) type: 3-coil. - Independent control of each sub-bank. - Each sub-bank is controlled by a cycler unit and 3 identical power racks, each including 4 identical power modules and a common power-supply module. - Coil-per-coil digital control: each power module embeds power-conversion, current-control, and current-monitoring functions for one coil. Control and monitoring are carried out by separate electronics in the module. Current is digitized and fully monitored by means of min-max templates. - A double-hold function is included: a power module assigned to a gripper will activate its coil if a fault risking to cause a reactor trip occurs. - Power modules are standardized, hot-pluggable and self-configured: a power module includes a set of parameters for each type of coil SG, MG, LC. The module recognizes the rack it is plugged in, and chooses automatically parameters to be used. Main benefits: - Reduced operational, maintenance, training, and inventory costs: standardization of power modules and integration of control and monitoring on the same PC-card lead to a drastic reduction of spare part types, and simplification of the system. - Easy maintenance: - Replacement of a power module solves nearly all failures due to current control or monitoring for a coil. It is done instantly thanks to hot-plug capability. - On the front plate of power-modules, LEDs provide useful information for diagnostic: current setpoint from cycler, output current bar

  7. Lifting scheme-based method for joint coding 3D stereo digital cinema with luminace correction and optimized prediction

    Science.gov (United States)

    Darazi, R.; Gouze, A.; Macq, B.

    2009-01-01

    Reproducing a natural and real scene as we see in the real world everyday is becoming more and more popular. Stereoscopic and multi-view techniques are used for this end. However due to the fact that more information are displayed requires supporting technologies such as digital compression to ensure the storage and transmission of the sequences. In this paper, a new scheme for stereo image coding is proposed. The original left and right images are jointly coded. The main idea is to optimally exploit the existing correlation between the two images. This is done by the design of an efficient transform that reduces the existing redundancy in the stereo image pair. This approach was inspired by Lifting Scheme (LS). The novelty in our work is that the prediction step is been replaced by an hybrid step that consists in disparity compensation followed by luminance correction and an optimized prediction step. The proposed scheme can be used for lossless and for lossy coding. Experimental results show improvement in terms of performance and complexity compared to recently proposed methods.

  8. Novel neural networks-based fault tolerant control scheme with fault alarm.

    Science.gov (United States)

    Shen, Qikun; Jiang, Bin; Shi, Peng; Lim, Cheng-Chew

    2014-11-01

    In this paper, the problem of adaptive active fault-tolerant control for a class of nonlinear systems with unknown actuator fault is investigated. The actuator fault is assumed to have no traditional affine appearance of the system state variables and control input. The useful property of the basis function of the radial basis function neural network (NN), which will be used in the design of the fault tolerant controller, is explored. Based on the analysis of the design of normal and passive fault tolerant controllers, by using the implicit function theorem, a novel NN-based active fault-tolerant control scheme with fault alarm is proposed. Comparing with results in the literature, the fault-tolerant control scheme can minimize the time delay between fault occurrence and accommodation that is called the time delay due to fault diagnosis, and reduce the adverse effect on system performance. In addition, the FTC scheme has the advantages of a passive fault-tolerant control scheme as well as the traditional active fault-tolerant control scheme's properties. Furthermore, the fault-tolerant control scheme requires no additional fault detection and isolation model which is necessary in the traditional active fault-tolerant control scheme. Finally, simulation results are presented to demonstrate the efficiency of the developed techniques.

  9. Universal block diagram based modeling and simulation schemes for fractional-order control systems.

    Science.gov (United States)

    Bai, Lu; Xue, Dingyü

    2017-05-08

    Universal block diagram based schemes are proposed for modeling and simulating the fractional-order control systems in this paper. A fractional operator block in Simulink is designed to evaluate the fractional-order derivative and integral. Based on the block, the fractional-order control systems with zero initial conditions can be modeled conveniently. For modeling the system with nonzero initial conditions, the auxiliary signal is constructed in the compensation scheme. Since the compensation scheme is very complicated, therefore the integrator chain scheme is further proposed to simplify the modeling procedures. The accuracy and effectiveness of the schemes are assessed in the examples, the computation results testify the block diagram scheme is efficient for all Caputo fractional-order ordinary differential equations (FODEs) of any complexity, including the implicit Caputo FODEs. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. A Quantum Proxy Weak Blind Signature Scheme Based on Controlled Quantum Teleportation

    Science.gov (United States)

    Cao, Hai-Jing; Yu, Yao-Feng; Song, Qin; Gao, Lan-Xiang

    2015-04-01

    Proxy blind signature is applied to the electronic paying system, electronic voting system, mobile agent system, security of internet, etc. A quantum proxy weak blind signature scheme is proposed in this paper. It is based on controlled quantum teleportation. Five-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to implement message blinding, so it could guarantee not only the unconditional security of the scheme but also the anonymity of the messages owner.

  11. Power pulsing scheme for analog and digital electronics of the vertex detectors at CLIC

    CERN Document Server

    Blanchot, Georges

    2015-01-01

    The precision requirements of the vertex detector at CLIC impose strong limitations on the mass of such a detector (< 0.2% of a radiation length, Xo, per layer). To achieve such a low material budget, ultra-thin hybrid pixel detectors are foreseen, while the mass for cooling and services will be reduced by implementing a power pulsing scheme that takes advantage of the low duty cycle of the accelerator. The principal aim is to achieve significant power reduction without compromising the power integrity supplied to the front-end electronics. This report summarises the study of a power pulsing scheme to power the vertex barrel electronics of the future CLIC experiment. Its main goal is to describe in more detail what has been already presented in TWEPP conferences and other presentations. The report can therefore serve as an operator manual for future use and development of the system

  12. Coordinated Voltage Control Scheme for VSC-HVDC Connected Wind Power Plants

    OpenAIRE

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei; Zhao, Haoran; Østergaard, Jacob

    2017-01-01

    This paper proposes a coordinated voltage control scheme based on model predictive control (MPC) for voltage source converter‐based high voltage direct current (VSC‐HVDC) connected wind power plants (WPPs). In the proposed scheme, voltage regulation capabilities of VSC and WTGs are fully utilized and optimally coordinated. Two control modes, namely operation optimization mode and corrective mode, are designed to coordinate voltage control and economic operation of the system. In the first mod...

  13. Documenting control system functionality for digital control implementations

    International Nuclear Information System (INIS)

    Harber, J.; Borairi, M.; Tikku, S.; Josefowicz, A.

    2006-01-01

    In past CANDU designs, plant control was accomplished by a combination of digital control computers, analogue controllers, and hardwired relay logic. Functionality for these various control systems, each using different hardware, was documented in varied formats such as text based program specifications, relay logic diagrams, and other various specification documents. The choice of formats was influenced by the hardware used and often required different specialized skills for different applications. The programmable electronic systems in new CANDU designs are realized in a manner consistent with latest international standards (e.g., the IEC 61513 standard). New CANDU designs make extensive use of modern digital control technology, with the benefit that functionality can be implemented on a limited number of control platforms, reducing development and maintenance cost. This approach can take advantage of tools that allow the plant control system functional and performance requirements to be documented using graphical representations. Modern graphical methods supplemented by information databases can be used to provide a clear and comprehensive set of requirements for software and system development. Overview diagrams of system functionality provide a common understanding of the system boundaries and interfaces. Important requirements are readily traced through the development process. This improved reviewability helps to ensure consistency with the safety and and production design requirements of the system. Encapsulation of commonly used functions into custom-defined function blocks, such as typical motor control centre interfaces, process interlocks, median selects etc, eases the burden on designers to understand and analyze the detailed functionality of each instance of use of this logic. A library of encapsulated functions will be established for complex functions that are reused in the control logic development. By encapsulation and standardisation of such

  14. The development of digital oscilloscope control software in nuclear measurement

    International Nuclear Information System (INIS)

    Pu Minghui; Tian Geng; Li Xianyou

    2004-01-01

    This essay presents the development of an all-purpose digital oscilloscope control software on Windows 95/98 OS. The background and method are discussed in detail, together with the function and characteristics of the software. With the use of this software, a single PC can control several digital oscilloscopes. Solution of main problems encountered in the development is also discussed. (authors)

  15. MATLAB simulation for an experimental setup of digital feedback control

    International Nuclear Information System (INIS)

    Zheng Lifang; Liu Songqiang

    2005-01-01

    This paper describes the digital feedback simulation using MATLAB for an experimental accelerator control setup. By analyzing the plant characteristic in time-domain and frequency-domain, a guideline for design of digital filter and PID controller is derived. (authors)

  16. An effective coded excitation scheme based on a predistorted FM signal and an optimized digital filter

    DEFF Research Database (Denmark)

    Misaridis, Thanasis; Jensen, Jørgen Arendt

    1999-01-01

    This paper presents a coded excitation imaging system based on a predistorted FM excitation and a digital compression filter designed for medical ultrasonic applications, in order to preserve both axial resolution and contrast. In radars, optimal Chebyshev windows efficiently weight a nearly...... is applied on receive, contrast or resolution can be traded in for range sidelobe levels down to -86 dB. The digital filter is designed to efficiently use the available bandwidth and at the same time to be insensitive to the transducer's impulse response. For evaluation of the method, simulations were...... performed with the program Field II. A commercial scanner (B-K Medical 3535) was modified and interfaced to an arbitrary function generator along with an RF power amplifier (Ritec). Hydrophone measurements in water were done to establish excitation voltage and corresponding intensity levels (I-sptp and I...

  17. Remote automatic control scheme for plasma arc cutting of contaminated waste

    International Nuclear Information System (INIS)

    Dudar, A.M.; Ward, C.R.; Kriikku, E.M.

    1993-01-01

    The Robotics Development Group at the Savannah River Technology Center has developed and implemented a scheme to perform automatic cutting of metallic contaminated waste. The scheme employs a plasma arc cutter in conjunction with a laser ranging sensor attached to a robotic manipulator called the Telerobot. A software algorithm using proportional control is then used to perturb the robot's trajectory in such a way as to regulate the plasma arc standoff and the robot's speed in order to achieve automatic plasma arc cuts. The scheme has been successfully tested on simulated waste materials and the results have been very favorable. This report details the development and testing of the scheme

  18. Integration of Fault Detection and Isolation with Control Using Neuro-fuzzy Scheme

    Directory of Open Access Journals (Sweden)

    A. Asokan

    2009-10-01

    Full Text Available In this paper an algorithms is developed for fault diagnosis and fault tolerant control strategy for nonlinear systems subjected to an unknown time-varying fault. At first, the design of fault diagnosis scheme is performed using model based fault detection technique. The neuro-fuzzy chi-square scheme is applied for fault detection and isolation. The fault magnitude and time of occurrence of fault is obtained through neuro-fuzzy chi-square scheme. The estimated magnitude of the fault magnitude is normalized and used by the feed-forward control algorithm to make appropriate changes in the manipulated variable to keep the controlled variable near its set value. The feed-forward controller acts along with feed-back controller to control the multivariable system. The performance of the proposed scheme is applied to a three- tank process for various types of fault inputs to show the effectiveness of the proposed approach.

  19. Exploring the role of voluntary disease schemes on UK farmer bio-security behaviours: Findings from the Norfolk-Suffolk Bovine Viral Diarrhoea control scheme.

    Science.gov (United States)

    Azbel-Jackson, Lena; Heffernan, Claire; Gunn, George; Brownlie, Joe

    2018-01-01

    The article describes the influence of a disease control scheme (the Norfolk-Suffolk Bovine Viral Diarrhoea Disease (BVD) Eradication scheme) on farmers' bio-security attitudes and behaviours. In 2010, a survey of 100 cattle farmers (53 scheme members vs. 47 out of scheme farmers) was undertaken among cattle farmers residing in Norfolk and Suffolk counties in the UK. A cross-sectional independent measures design was employed. The main analytical tool was content analysis. The following variables at the farmer-level were explored: the specific BVD control measures adopted, livestock disease priorities, motivation for scheme membership, wider knowledge acquisition, biosecurity behaviours employed and training course attendance. The findings suggest that participation in the BVD scheme improved farmers' perception of the scheme benefits and participation in training courses. However, no association was found between the taking part in the BVD scheme and livestock disease priorities or motivation for scheme participation, or knowledge about BVD bio-security measures employed. Equally importantly, scheme membership did appear to influence the importance accorded specific bio-security measures. Yet such ranking did not appear to reflect the actual behaviours undertaken. As such, disease control efforts alone while necessary, are insufficient. Rather, to enhance farmer bio-security behaviours significant effort must be made to address underlying attitudes to the specific disease threat involved.

  20. Observerless Scheme for Sensorless Speed Control of PMSM Using Direct Torque Control Method With LP Filter

    Directory of Open Access Journals (Sweden)

    BEKIROGLU, N.

    2010-08-01

    Full Text Available In this study, direct torque control (DTC of a permanent magnet synchronous motor is realized with a sensorless speed control technique without using an observer. Space vector pulse width modulation (SVPWM technique is applied in order to determine the switching sequence of the voltage source inverter. Torque and flux, the main variables of the DTC, are estimated by using the mathematical model of the motor. Estimated torque and flux values are compared with their references in every control cycle. Then, according to the torque and flux demand, the voltage vector is constituted. In the proposed control scheme, speed is estimated by using flux calculations and a PI controller is used to process the torque and flux errors. Furthermore, a low-pass (LP filter is implemented within the proposed system for voltage and current harmonics suppression. The results proved that proposed scheme for the DTC provides the speed control under various torque demands without employing a sensor. The proposed system performs very well for a sensorless operation and effectively eliminates the harmonics due to the LP filter.

  1. A practical fast acting control scheme for fuzzy logic-based voltage stabilization control

    Directory of Open Access Journals (Sweden)

    El-Kholy E.E.

    2005-01-01

    Full Text Available This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT’s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems are presented. A high speed Digital Signal Processor is used for implementing proportional integral (PI and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results.

  2. A Practical Fast Acting Control Scheme For Fuzzy Logic-Based Voltage Stabilization Control

    Directory of Open Access Journals (Sweden)

    E. E. EL-Kholy

    2005-03-01

    Full Text Available This paper presents a simplified control model for stabilizing a load voltage using a switched reactor in parallel with a fixed capacitor of static VAR compensator. Two IGBT’s are used to control the reactance of the switched reactor. A uniform pulse width modulation is used for controlling the two switches. The compensator has a simple control circuit and structure. A complete modeling and numerical simulation for the proposed systems is presented. A high speed Digital Signal Processor is used for implementing proportional-integral (PI and fuzzy load voltage controllers. Experimental results indicate the superiority of fuzzy logic control over the conventional proportional-integral control method. Simulation results are reported and proved to be in good agreement with the relevant experimental results.

  3. Block-classified bidirectional motion compensation scheme for wavelet-decomposed digital video

    Energy Technology Data Exchange (ETDEWEB)

    Zafar, S. [Argonne National Lab., IL (United States). Mathematics and Computer Science Div.; Zhang, Y.Q. [David Sarnoff Research Center, Princeton, NJ (United States); Jabbari, B. [George Mason Univ., Fairfax, VA (United States)

    1997-08-01

    In this paper the authors introduce a block-classified bidirectional motion compensation scheme for the previously developed wavelet-based video codec, where multiresolution motion estimation is performed in the wavelet domain. The frame classification structure described in this paper is similar to that used in the MPEG standard. Specifically, the I-frames are intraframe coded, the P-frames are interpolated from a previous I- or a P-frame, and the B-frames are bidirectional interpolated frames. They apply this frame classification structure to the wavelet domain with variable block sizes and multiresolution representation. They use a symmetric bidirectional scheme for the B-frames and classify the motion blocks as intraframe, compensated either from the preceding or the following frame, or bidirectional (i.e., compensated based on which type yields the minimum energy). They also introduce the concept of F-frames, which are analogous to P-frames but are predicted from the following frame only. This improves the overall quality of the reconstruction in a group of pictures (GOP) but at the expense of extra buffering. They also study the effect of quantization of the I-frames on the reconstruction of a GOP, and they provide intuitive explanation for the results. In addition, the authors study a variety of wavelet filter-banks to be used in a multiresolution motion-compensated hierarchical video codec.

  4. Evaluation of the use of digital images for a national prostate core external quality assurance scheme.

    Science.gov (United States)

    Harnden, Patricia; Coleman, Derek; Moss, Sue; Kodikara, Sandhya; Griffin, Nick R; Melia, Jane

    2011-10-01

    To evaluate the use of virtual images as an alternative to glass slides to expand the number of participants in the External Quality Assurance Scheme for prostatic biopsies. Benign and neoplastic cases, previously circulated as glass slides, were selected to include cases that had demonstrated a high level of agreement (n = 10) and a lesser degree of agreement (n = 10). Whole slide virtual images were circulated to 68 pathologists; 51 responses were returned. The levels of agreement for the primary diagnosis and for Gleason grading of cancers were analysed using kappa statistics. Responses for glass slides versus images were compared for the 24 pathologists for whom data were available. Levels of agreement for diagnostic categories using virtual slides were moderate to substantial, comparable to those found using glass slides. The level of agreement for Gleason grades 8-10 was substantial, but for lower grades was fair or moderate, poorer than for the glass slide circulation. Circulation of virtual images of biopsy material is a suitable alternative to glass slide-based schemes for the evaluation of diagnostic consistency. The majority of participants agreed that the ability to evaluate limited diagnostic material outweighed the disadvantages of a virtual system. 2011 Blackwell Publishing Limited.

  5. Graphical Evaluation of Time-Delay Compensation Techniques for Digitally Controlled Converters

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Loh, Poh Chiang

    2018-01-01

    A main design constraint of the digitally controlled power electronics converters is the time delay of control systems, which may lead to the reduced control loop bandwidth and even unstable dynamics. Numerous time-delay compensation methods have been developed, of which the model-free schemes...... are independent to model accuracy whereas the model-based alternatives are sensitive to system modeling. This paper first presents a graphical illustration of four model-free delay compensation techniques, where their principles and performances are intuitively elaborated and compared by means of the impulse area....... Simulations and experimental test results validate the effectiveness of the graphical comparisons and the proposed approach....

  6. Resolution improvement in off-axis digital holography using an iterative scheme

    Science.gov (United States)

    He, Jing; Liu, Cheng; Veetil, Suhas P.; Gao, Shumei; Wang, Jicheng; Wang, Yueke

    2014-08-01

    The image quality in off-axis digital holography (DH) is often degraded by inaccuracies in the reference wave used for reconstruction and the spatial filtering adopted to avoid twin images and zeroth order diffraction. To enhance the image quality in such cases, coherent diffraction imaging is combined with a DH technique to iteratively reconstruct the hologram. By using a small aperture on the sample plane as a spatial constraint and the recorded diffraction pattern as an intensity constraint, a higher spatial resolution than usual is obtained with the proposed method.

  7. An Embedded Based Digital Controller for Thermal Process

    Directory of Open Access Journals (Sweden)

    A. Lakshmi Sangeetha

    2008-01-01

    Full Text Available This paper describes a low cost virtual instrumentation (VI system to monitor and control the electrically heated water bath temperature. The PIC16F877 based digital microcontroller is used as thermostat which controls and monitors the temperature. The digital controller also allows the user to modify the sensor (PT100 calibration data values if necessary. The developed programmable on/off control function provides on-line display of measuring temperature, set point as well as the control function output plots through the parallel port. This bus interaction is realized in Visual Basic/Assembly Language and uses a 16 bit, 10 ms sampling analog-to-digital converter (ADS 7805 for monitoring and controlling the parameters of the temperature local digital controller.

  8. REVIEW OF NRC APPROVED DIGITAL CONTROL SYSTEMS ANALYSIS

    International Nuclear Information System (INIS)

    Markman, D.W.

    1999-01-01

    Preliminary design concepts for the proposed Subsurface Repository at Yucca Mountain indicate extensive reliance on modern, computer-based, digital control technologies. The purpose of this analysis is to investigate the degree to which the U. S. Nuclear Regulatory Commission (NRC) has accepted and approved the use of digital control technology for safety-related applications within the nuclear power industry. This analysis reviews cases of existing digitally-based control systems that have been approved by the NRC. These cases can serve as precedence for using similar types of digitally-based control technologies within the Subsurface Repository. While it is anticipated that the Yucca Mountain Project (YMP) will not contain control systems as complex as those required for a nuclear power plant, the review of these existing NRC approved applications will provide the YMP with valuable insight into the NRCs review process and design expectations for safety-related digital control systems. According to the YMP Compliance Program Guidance, portions of various NUREGS, Regulatory Guidelines, and nuclear IEEE standards the nuclear power plant safety related concept would be applied to some of the designs on a case-by-case basis. This analysis will consider key design methods, capabilities, successes, and important limitations or problems of selected control systems that have been approved for use in the Nuclear Power industry. An additional purpose of this analysis is to provide background information in support of further development of design criteria for the YMP. The scope and primary objectives of this analysis are to: (1) Identify and research the extent and precedence of digital control and remotely operated systems approved by the NRC for the nuclear power industry. Help provide a basis for using and relying on digital technologies for nuclear related safety critical applications. (2) Identify the basic control architecture and methods of key digital control

  9. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    Science.gov (United States)

    Pal, Sandip; McCann, Hugh

    2011-11-01

    In many dynamic gas-phase reaction processes, there is great interest to measure the distribution of minor constituents, i.e. gasoline engine exhaust by catalytic conversion, where a characteristic challenge is to image the distribution of 10 ppm (average) of carbon monoxide (CO) at 1000 frames per second across a 50 mm diameter exhaust pipe; this particular problem has been pursued as a case study. In this paper, we present a novel electronic scheme that achieves the required measurement of around 10-3 absorption with 10-4 precision at kHz bandwidth. This was not previously achievable with any known technology. We call the new scheme Auto-Digital Gain Balancing. It is amenable to replication for many simultaneous measurement channels, and it permits simultaneous measurement of multiple species, in some circumstances. Experimental demonstrations are presented in the near-infrared. In single scans of a tunable diode laser, measurements of both CO and CO2 have been made with 20 dB signal-to-noise ratio at peak absorption. This work paves the way for chemical species tomography of minor constituents in many dynamic gas-phase systems.

  10. Regulation control and energy management scheme for wireless power transfer

    Science.gov (United States)

    Miller, John M.

    2015-12-29

    Power transfer rate at a charging facility can be maximized by employing a feedback scheme. The state of charge (SOC) and temperature of the regenerative energy storage system (RESS) pack of a vehicle is monitored to determine the load due to the RESS pack. An optimal frequency that cancels the imaginary component of the input impedance for the output signal from a grid converter is calculated from the load of the RESS pack, and a frequency offset f* is made to the nominal frequency f.sub.0 of the grid converter output based on the resonance frequency of a magnetically coupled circuit. The optimal frequency can maximize the efficiency of the power transfer. Further, an optimal grid converter duty ratio d* can be derived from the charge rate of the RESS pack. The grid converter duty ratio d* regulates wireless power transfer (WPT) power level.

  11. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope.

    Science.gov (United States)

    Lee, Jungshin; Yun, Sung Wook; Rhim, Jaewook

    2016-04-20

    A Hemispherical Resonator Gyro (HRG) is the Coriolis Vibratory Gyro (CVG) that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL), amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments.

  12. Design and Verification of a Digital Controller for a 2-Piece Hemispherical Resonator Gyroscope

    Directory of Open Access Journals (Sweden)

    Jungshin Lee

    2016-04-01

    Full Text Available A Hemispherical Resonator Gyro (HRG is the Coriolis Vibratory Gyro (CVG that measures rotation angle or angular velocity using Coriolis force acting the vibrating mass. A HRG can be used as a rate gyro or integrating gyro without structural modification by simply changing the control scheme. In this paper, differential control algorithms are designed for a 2-piece HRG. To design a precision controller, the electromechanical modelling and signal processing must be pre-performed accurately. Therefore, the equations of motion for the HRG resonator with switched harmonic excitations are derived with the Duhamel Integral method. Electromechanical modeling of the resonator, electric module and charge amplifier is performed by considering the mode shape of a thin hemispherical shell. Further, signal processing and control algorithms are designed. The multi-flexing scheme of sensing, driving cycles and x, y-axis switching cycles is appropriate for high precision and low maneuverability systems. The differential control scheme is easily capable of rejecting the common mode errors of x, y-axis signals and changing the rate integrating mode on basis of these studies. In the rate gyro mode the controller is composed of Phase-Locked Loop (PLL, amplitude, quadrature and rate control loop. All controllers are designed on basis of a digital PI controller. The signal processing and control algorithms are verified through Matlab/Simulink simulations. Finally, a FPGA and DSP board with these algorithms is verified through experiments.

  13. Adaptive Numerical Dissipative Control in High Order Schemes for Multi-D Non-Ideal MHD

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, B.

    2004-01-01

    The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free of numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multi-resolution wavelets (WAV) (for the above types of flow feature). These filter approaches also provide a natural and efficient way for the minimization of Div(B) numerical error. The filter scheme consists of spatially sixth order or higher non-dissipative spatial difference operators as the base scheme for the inviscid flux derivatives. If necessary, a small amount of high order linear dissipation is used to remove spurious high frequency oscillations. For example, an eighth-order centered linear dissipation (AD8) might be included in conjunction with a spatially sixth-order base scheme. The inviscid difference operator is applied twice for the viscous flux derivatives. After the completion of a full time step of the base scheme step, the solution is adaptively filtered by the product of a 'flow detector' and the 'nonlinear dissipative portion' of a high-resolution shock-capturing scheme. In addition, the scheme independent wavelet flow detector can be used in conjunction with spatially compact, spectral or spectral element type of base schemes. The ACM and wavelet filter schemes using the dissipative portion of a second-order shock-capturing scheme with sixth-order spatial central base scheme for both the inviscid and viscous MHD flux

  14. A Hierarchical Control Scheme for Reactive Power and Harmonic Current Sharing in Islanded Microgrids

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

    2015-01-01

    In this paper, a hierarchical control scheme consisting of primary and secondary levels is proposed for achieving accurate reactive power and harmonic currents sharing among interface inverters of distributed generators (DGs) in islanded microgrids. Firstly, fundamental and main harmonic componen...

  15. An intelligent control scheme for precise tip-motion control in atomic force microscopy.

    Science.gov (United States)

    Wang, Yanyan; Hu, Xiaodong; Xu, Linyan

    2016-01-01

    The paper proposes a new intelligent control method to precisely control the tip motion of the atomic force microscopy (AFM). The tip moves up and down at a high rate along the z direction during scanning, requiring the utilization of a rapid feedback controller. The standard proportional-integral (PI) feedback controller is commonly used in commercial AFMs to enable topography measurements. The controller's response performance is determined by the set of the proportional (P) parameter and the integral (I) parameter. However, the two parameters cannot be automatically altered simultaneously according to the scanning speed and the surface topography during continuors scanning, leading to an inaccurate measurement. Thus a new intelligent controller combining the fuzzy controller and the PI controller is put forward in the paper. The new controller automatically selects the most appropriate PI parameters to achieve a fast response rate on basis of the tracking errors. In the experimental setup, the new controller is realized with a digital signal process (DSP) system, implemented in a conventional AFM system. Experiments are carried out by comparing the new method with the standard PI controller. The results demonstrate that the new method is more robust and effective for the precise tip motion control, corresponding to the achievement of a highly qualified image by shortening the response time of the controller. © Wiley Periodicals, Inc.

  16. Knowledge-Based Trajectory Error Pattern Method Applied to an Active Force Control Scheme

    Directory of Open Access Journals (Sweden)

    Endra Pitowarno, Musa Mailah, Hishamuddin Jamaluddin

    2012-08-01

    Full Text Available The active force control (AFC method is known as a robust control scheme that dramatically enhances the performance of a robot arm particularly in compensating the disturbance effects. The main task of the AFC method is to estimate the inertia matrix in the feedback loop to provide the correct (motor torque required to cancel out these disturbances. Several intelligent control schemes have already been introduced to enhance the estimation methods of acquiring the inertia matrix such as those using neural network, iterative learning and fuzzy logic. In this paper, we propose an alternative scheme called Knowledge-Based Trajectory Error Pattern Method (KBTEPM to suppress the trajectory track error of the AFC scheme. The knowledge is developed from the trajectory track error characteristic based on the previous experimental results of the crude approximation method. It produces a unique, new and desirable error pattern when a trajectory command is forced. An experimental study was performed using simulation work on the AFC scheme with KBTEPM applied to a two-planar manipulator in which a set of rule-based algorithm is derived. A number of previous AFC schemes are also reviewed as benchmark. The simulation results show that the AFC-KBTEPM scheme successfully reduces the trajectory track error significantly even in the presence of the introduced disturbances.Key Words:  Active force control, estimated inertia matrix, robot arm, trajectory error pattern, knowledge-based.

  17. Compensation of phase aberration by using a virtual confocal scheme in digital holographic microscopy.

    Science.gov (United States)

    Chew, Yang-Kun; Shiu, Min-Tzung; Wang, Je-Chung; Chang, Chi-Ching

    2014-09-20

    This work presents cost-effective, simple arbitrary phase-step digital holographic microscopy to suppress both zero-order and twin-image terms. A virtual confocal offset lens under in-line configuration is also used to compensate for the introduced quadratic phase by using a microscope objective lens. In addition to reducing the difficulties of physical confocal configurations, the proposed method significantly increases the magnification power, ultimately achieving the purposes of an optical zoom. An attempt is also made to reduce the noise interference of a high magnification system by developing a long focal lens to reduce light detection size, subsequently gaining an approximately plane wave light source to illuminate the object within the effective depth of focus. Experimental results indicate that the proposed high magnification system can be elevated with low noise interference, and image reconstruction without quadratic phase terms.

  18. Control Methods Utilizing Energy Optimizing Schemes in Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, L.S; Thybo, C.; Stoustrup, Jakob

    2003-01-01

    The potential energy savings in refrigeration systems using energy optimal control has been proved to be substantial. This however requires an intelligent control that drives the refrigeration systems towards the energy optimal state. This paper proposes an approach for a control, which drives...

  19. Robust digital controllers for uncertain chaotic systems: A digital redesign approach

    Energy Technology Data Exchange (ETDEWEB)

    Ababneh, Mohammad [Department of Controls, FMC Kongsberg Subsea, FMC Energy Systems, Houston, TX 77067 (United States); Barajas-Ramirez, Juan-Gonzalo [CICESE, Depto. De Electronica y Telecomunicaciones, Ensenada, BC, 22860 (Mexico); Chen Guanrong [Centre for Chaos Control and Synchronization, Department of Electronic Engineering, City University of Hong Kong (China); Shieh, Leang S. [Department of Electrical and Computer Engineering, University of Houston, Houston, TX 77204-4005 (United States)

    2007-03-15

    In this paper, a new and systematic method for designing robust digital controllers for uncertain nonlinear systems with structured uncertainties is presented. In the proposed method, a controller is designed in terms of the optimal linear model representation of the nominal system around each operating point of the trajectory, while the uncertainties are decomposed such that the uncertain nonlinear system can be rewritten as a set of local linear models with disturbed inputs. Applying conventional robust control techniques, continuous-time robust controllers are first designed to eliminate the effects of the uncertainties on the underlying system. Then, a robust digital controller is obtained as the result of a digital redesign of the designed continuous-time robust controller using the state-matching technique. The effectiveness of the proposed controller design method is illustrated through some numerical examples on complex nonlinear systems--chaotic systems.

  20. Digital signal processing in power system protection and control

    CERN Document Server

    Rebizant, Waldemar; Wiszniewski, Andrzej

    2011-01-01

    Digital Signal Processing in Power System Protection and Control bridges the gap between the theory of protection and control and the practical applications of protection equipment. Understanding how protection functions is crucial not only for equipment developers and manufacturers, but also for their users who need to install, set and operate the protection devices in an appropriate manner. After introductory chapters related to protection technology and functions, Digital Signal Processing in Power System Protection and Control presents the digital algorithms for signal filtering, followed

  1. Control Methods Utilizing Energy Optimizing Schemes in Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, L.S; Thybo, C.; Stoustrup, Jakob

    2003-01-01

    The potential energy savings in refrigeration systems using energy optimal control has been proved to be substantial. This however requires an intelligent control that drives the refrigeration systems towards the energy optimal state. This paper proposes an approach for a control, which drives...... the condenser pressure towards an optimal state. The objective of this is to present a feasible method that can be used for energy optimizing control. A simulation model of a simple refrigeration system will be used as basis for testing the control method....

  2. Frequency and time domain characteristics of digital control of electric vehicle in-wheel drives

    Directory of Open Access Journals (Sweden)

    Jarzebowicz Leszek

    2017-12-01

    Full Text Available In-wheel electric drives are promising as actuators in active safety systems of electric and hybrid vehicles. This new function requires dedicated control algorithms, making it essential to deliver models that reflect better the wheel-torque control dynamics of electric drives. The timing of digital control events, whose importance is stressed in current research, still lacks an analytical description allowing for modeling its influence on control system dynamics. In this paper, authors investigate and compare approaches to the analog and discrete analytical modeling of torque control loop in digitally controlled electric drive. Five different analytical models of stator current torque component control are compared to judge their accuracy in representing drive control dynamics related to the timing of digital control events. The Bode characteristics and stepresponse characteristics of the analytical models are then compared with those of a reference model for three commonly used cases of motor discrete control schemes. Finally, the applicability of the presented models is discussed.

  3. Implementation of Adaptive Digital Controllers on Programmable Logic Devices

    Science.gov (United States)

    Gwaltney, David A.; King, Kenneth D.; Smith, Keary J.; Monenegro, Justino (Technical Monitor)

    2002-01-01

    Much has been made of the capabilities of FPGA's (Field Programmable Gate Arrays) in the hardware implementation of fast digital signal processing. Such capability also makes an FPGA a suitable platform for the digital implementation of closed loop controllers. Other researchers have implemented a variety of closed-loop digital controllers on FPGA's. Some of these controllers include the widely used proportional-integral-derivative (PID) controller, state space controllers, neural network and fuzzy logic based controllers. There are myriad advantages to utilizing an FPGA for discrete-time control functions which include the capability for reconfiguration when SRAM-based FPGA's are employed, fast parallel implementation of multiple control loops and implementations that can meet space level radiation tolerance requirements in a compact form-factor. Generally, a software implementation on a DSP (Digital Signal Processor) or microcontroller is used to implement digital controllers. At Marshall Space Flight Center, the Control Electronics Group has been studying adaptive discrete-time control of motor driven actuator systems using digital signal processor (DSP) devices. While small form factor, commercial DSP devices are now available with event capture, data conversion, pulse width modulated (PWM) outputs and communication peripherals, these devices are not currently available in designs and packages which meet space level radiation requirements. In general, very few DSP devices are produced that are designed to meet any level of radiation tolerance or hardness. The goal of this effort is to create a fully digital, flight ready controller design that utilizes an FPGA for implementation of signal conditioning for control feedback signals, generation of commands to the controlled system, and hardware insertion of adaptive control algorithm approaches. An alternative is required for compact implementation of such functionality to withstand the harsh environment

  4. A Robust Control Scheme for Medium-Voltage-Level DVR Implementation

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Li, Yun Wei

    2007-01-01

    of Hinfin controller weighting function selection, inner current loop tuning, and system disturbance rejection capability is presented. Finally, the designed control scheme is extensively tested on a laboratory 10-kV MV-level DVR system with varying voltage sag (balanced and unbalanced) and loading (linear......In this paper, a robust control scheme with an outer Hinfin voltage control loop and an inner current control loop is designed and implemented on a medium-voltage (MV)-level dynamic voltage restorer (DVR) system. Through a simple selection of weighting functions, the synthesized Hinfin controller....../nonlinear load and induction motor load) conditions. It is shown that the proposed control scheme is effective in both balanced and unbalanced sag compensation and load disturbance rejection, as its robustness is explicitly specified....

  5. A comparative study of the active force control schemes applied to robot arm

    International Nuclear Information System (INIS)

    Musa Mailah; Hewit, J.R.

    2000-01-01

    In this paper, a comparative study of three different types of active force control (AFC) schemes applied to a robotic arm is described. The study particularly focuses on the techniques to compute the estimated inertia matrix (ΙΝ) of a robotic manipulator necessary for the execution of the AFC strategy since the computation of (ΙΝ) is the common central theme to all AFC-based schemes. The first of the three AFC schemes is based on the conventional method of obtaining (ΙΝ), the second uses artificial neural network while the third incorporates an iterative learning algorithm. The study also discusses the characteristics of the (ΙΝ) curves obtained, the trajectory track performance of the schemes and the effects of the modelled disturbances. The robustness of all the AFC schemes are also ascertained in the study. (Author)

  6. An Optimal Control Scheme to Minimize Loads in Wind Farms

    DEFF Research Database (Denmark)

    Soleimanzadeh, Maryam; Wisniewski, Rafal

    2012-01-01

    This work presents a control algorithm for wind farms that optimizes the power production of the farm and helps to increase the lifetime of wind turbines components. The control algorithm is a centralized approach, and it determines the power reference signals for individual wind turbines...... such that the structural loads of the wind turbines in low frequencies are reduced. The controller is relatively easy to implement on a wind farm, and in here the results of simulating the controller on a small wind farm is presented....

  7. Digital Control of a power conditioner for fuel cell/super-capacitor hybrid system

    DEFF Research Database (Denmark)

    Caballero, Juan C Trujillo; Gomis-Bellmunt, Oriol; Montesinos-Miracle, Daniel

    2014-01-01

    This article proposes a digital control scheme to operate a proton exchange membrane fuel cell module of 1.2 kW and a super-capacitor through a DC/DC hybrid converter. A fuel cell has been proposed as a primary source of energy, and a super-capacitor has been proposed as an auxiliary source...... of energy. Experimental validation of the system implemented in the laboratory is provided. Several tests have been performed to verify that the system achieves excellent output voltage (V0) regulation and super-capacitor voltage (V SC) control under disturbances from fuel cell power (PFC) and output power...

  8. Coordinated Voltage Control Scheme for VSC-HVDC Connected Wind Power Plants

    DEFF Research Database (Denmark)

    Guo, Yifei; Gao, Houlei; Wu, Qiuwei

    2017-01-01

    This paper proposes a coordinated voltage control scheme based on model predictive control (MPC) for voltage source converter‐based high voltage direct current (VSC‐HVDC) connected wind power plants (WPPs). In the proposed scheme, voltage regulation capabilities of VSC and WTGs are fully utilized...... and optimally coordinated. Two control modes, namely operation optimization mode and corrective mode, are designed to coordinate voltage control and economic operation of the system. In the first mode, the control objective includes the bus voltages, power losses and dynamic Var reserves of wind turbine...

  9. An Enhanced Control Scheme for Uninterruptible Power Supply

    DEFF Research Database (Denmark)

    Lu, Jinghang; Savaghebi, Mehdi; Wei, Baoze

    2017-01-01

    To address the active power feeding issue in the parallel Uninterruptible Power Supply (UPS) system, a DC-link Voltage Protection (DCVP) control strategy is proposed in this paper. The proposed control method only relies on local load information, which increases the system reliability...

  10. Adaptive control schemes for mobile robot formations with triangularised structures

    NARCIS (Netherlands)

    Guo, J.; Lin, Z.; Cao, M.; Yan, G.

    The study investigates the leader-follower formation control problem, for which the objective is to control a group of robots such that they move as a rigid formation with a prescribed constant velocity. It is assumed in the study that there are two leader robots, who are the only robots in the

  11. State of the art of control schemes for smart systems featuring magneto-rheological materials

    International Nuclear Information System (INIS)

    Choi, Seung-Bok; Do, Phu Xuan; Li, Weihua; Yu, Miao; Fu, Jie; Du, Haiping

    2016-01-01

    This review presents various control strategies for application systems utilizing smart magneto-rheological fluid (MRF) and magneto-rheological elastomers (MRE). It is well known that both MRF and MRE are actively studied and applied to many practical systems such as vehicle dampers. The mandatory requirements for successful applications of MRF and MRE include several factors: advanced material properties, optimal mechanisms, suitable modeling, and appropriate control schemes. Among these requirements, the use of an appropriate control scheme is a crucial factor since it is the final action stage of the application systems to achieve the desired output responses. There are numerous different control strategies which have been applied to many different application systems of MRF and MRE, summarized in this review. In the literature review, advantages and disadvantages of each control scheme are discussed so that potential researchers can develop more effective strategies to achieve higher control performance of many application systems utilizing magneto-rheological materials. (topical review)

  12. A low order adaptive control scheme for hydraulic servo systems

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Pedersen, Henrik Clemmensen; Bech, Michael Møller

    2015-01-01

    , active gain feedforward shows a slightly improved performance. Computed-Torque Control shows better performance, but requires a well described system for best performance. A novel Adaptive Inverse Dynamics Controller was tested and the performance was found to be similar to that of Computed...... system were constructed and linearized. Controllers are implemented and tested on the manipulator. Pressure feedback was found to greatly improve system stability margins. Passive gain feedforward shows improved tracking performance for small changes in load pressure. For large changes in load pressure...

  13. Semantically Enhanced Online Configuration of Feedback Control Schemes.

    Science.gov (United States)

    Milis, Georgios M; Panayiotou, Christos G; Polycarpou, Marios M

    2018-03-01

    Recent progress toward the realization of the "Internet of Things" has improved the ability of physical and soft/cyber entities to operate effectively within large-scale, heterogeneous systems. It is important that such capacity be accompanied by feedback control capabilities sufficient to ensure that the overall systems behave according to their specifications and meet their functional objectives. To achieve this, such systems require new architectures that facilitate the online deployment, composition, interoperability, and scalability of control system components. Most current control systems lack scalability and interoperability because their design is based on a fixed configuration of specific components, with knowledge of their individual characteristics only implicitly passed through the design. This paper addresses the need for flexibility when replacing components or installing new components, which might occur when an existing component is upgraded or when a new application requires a new component, without the need to readjust or redesign the overall system. A semantically enhanced feedback control architecture is introduced for a class of systems, aimed at accommodating new components into a closed-loop control framework by exploiting the semantic inference capabilities of an ontology-based knowledge model. This architecture supports continuous operation of the control system, a crucial property for large-scale systems for which interruptions have negative impact on key performance metrics that may include human comfort and welfare or economy costs. A case-study example from the smart buildings domain is used to illustrate the proposed architecture and semantic inference mechanisms.

  14. Research on a New Control Scheme of Photovoltaic Grid Power Generation System

    Directory of Open Access Journals (Sweden)

    Dong-Hui Li

    2014-01-01

    Full Text Available A new type of photovoltaic grid power generation system control scheme to solve the problems of the conventional photovoltaic grid power generation systems is presented. To aim at the oscillation and misjudgment of traditional perturbation observation method, an improved perturbation observation method comparing to the next moment power is proposed, combining with BOOST step-up circuit to realize the maximum power tracking. To counter the harmonic pollution problem in photovoltaic grid power generation system, the deadbeat control scheme in fundamental wave synchronous frequency rotating coordinate system of power grid is presented. A parameter optimization scheme based on positive feedback of active frequency shift island detection to solve the problems like the nondetection zone due to the import of disturbance in traditional island detection method is proposed. Finally, the results in simulation environment by MATLAB/Simulink simulation and experiment environment verify the validity and superiority of the proposed scheme.

  15. An Effective Approach Control Scheme for the Tethered Space Robot System

    Directory of Open Access Journals (Sweden)

    Zhongjie Meng

    2014-09-01

    Full Text Available The tethered space robot system (TSR, which is composed of a platform, a gripper and a space tether, has great potential in future space missions. Given the relative motion among the platform, tether, gripper and the target, an integrated approach model is derived. Then, a novel coordinated approach control scheme is presented, in which the tether tension, thrusters and the reaction wheel are all utilized. It contains the open-loop trajectory optimization, the feedback trajectory control and attitude control. The numerical simulation results show that the rendezvous between TSR and the target can be realized by the proposed coordinated control scheme, and the propellant consumption is efficiently reduced. Moreover, the control scheme performs well in the presence of the initial state's perturbations, actuator characteristics and sensor errors.

  16. Gaming across different consoles: exploring the influence of control scheme on game-player enjoyment.

    Science.gov (United States)

    Limperos, Anthony M; Schmierbach, Michael G; Kegerise, Andrew D; Dardis, Frank E

    2011-06-01

    Many studies have investigated how different technological features impact the experience of playing video games, yet few have focused on how control schemes may affect the play experience. This research employed a between-subjects design to explore the relationship between the type of console played (Nintendo Wii, Playstation 2) and feelings of flow and enjoyment during the game-play experience. Results indicated that participants reported greater feelings of control and enjoyment with a traditional control scheme (Playstation 2) than with the more technologically advanced control scheme (Nintendo Wii). Further mediation analysis showed that enjoyment was driven by the sense of control that participants experienced and not simply by whether they won the game. Theoretical and practical implications are discussed.

  17. Comparative analysis of supercritical CO2 power conversion system control schemes

    International Nuclear Information System (INIS)

    Vilim, R.B.; Moisseytsev, A.

    2008-01-01

    A comparative analysis of control system performance was carried out for the S-CO 2 re-compressing cycle. In this study two control strategies were developed for managing process variables for a change in load at the electrical generator. Both relied on inventory control to reduce power but differed in other significant respects. In inventory control turbomachine mass flow rates are reduced through density change with the goal of preserving velocity triangle similarity and, hence, cycle efficiency. An inventory and low temperature control scheme was operated to maintain a trajectory that avoids close approach to the critical point by controlling the main compressor inlet temperature. Shaft power tracks a setpoint by controlling density. This control scheme may be preferred in plant configurations that use a flow-split. There the rapid density change with pressure near the critical point can lead to flow rate instability. An inventory and turbine bypass control scheme was operated to more closely approach the critical point. Inventory in addition to turbine bypass was used to control shaft power. The first control scheme yielded greater efficiency at reduced power as a result of two factors. First, bypassing coolant around the turbine increases the mass flow rate through the compressors while shaft speed is maintained constant. As a result the compressor velocity triangles are altered from their peak efficiency values. Second, the bypass flow rate results in non-isothermal mixing downstream where the turbine and bypass flow combine which also penalizes efficiency. (authors)

  18. Hardware replacements and software tools for digital control computers

    International Nuclear Information System (INIS)

    Walker, R.A.P.; Wang, B-C.; Fung, J.

    1996-01-01

    Technological obsolescence is an on-going challenge for all computer use. By design, and to some extent good fortune, AECL has had a good track record with respect to the march of obsolescence in CANDU digital control computer technology. Recognizing obsolescence as a fact of life, AECL has undertaken a program of supporting the digital control technology of existing CANDU plants. Other AECL groups are developing complete replacement systems for the digital control computers, and more advanced systems for the digital control computers of the future CANDU reactors. This paper presents the results of the efforts of AECL's DCC service support group to replace obsolete digital control computer and related components and to provide friendlier software technology related to the maintenance and use of digital control computers in CANDU. These efforts are expected to extend the current lifespan of existing digital control computers through their mandated life. This group applied two simple rules; the product, whether new or replacement should have a generic basis, and the products should be applicable to both existing CANDU plants and to 'repeat' plant designs built using current design guidelines. While some exceptions do apply, the rules have been met. The generic requirement dictates that the product should not be dependent on any brand technology, and should back-fit to and interface with any such technology which remains in the control design. The application requirement dictates that the product should have universal use and be user friendly to the greatest extent possible. Furthermore, both requirements were designed to anticipate user involvement, modifications and alternate user defined applications. The replacements for hardware components such as paper tape reader/punch, moving arm disk, contact scanner and Ramtek are discussed. The development of these hardware replacements coincide with the development of a gateway system for selected CANDU digital control

  19. Control and management scheme in a DWDM EPON

    NARCIS (Netherlands)

    Roy, R.; Manhoudt, Gert; Roeloffzen, C.G.H.; van Etten, Wim

    2006-01-01

    Passive Optical Networks (PONs) are a preferred architecture for distribution of bandwidth in the access network. The BSIK Freeband Broadband Photonics Project(BBP) looks at the design of a flexible DWDM PON which can be used to increase the bandwidth provided to the user. We present a control and

  20. Efficient rate control scheme using modified inter-layer dependency ...

    Indian Academy of Sciences (India)

    The IRC from the prior art is modified to achieve better rate control per layer by recursive updates for mean absolute difference values of eachbasic unit. Proposed modified inter-layer dependency shows improvement in the PSNR for enhancement layers while the updated IRC enforces better IRC for all the layers.

  1. Analysis of Contracting Processes, Internal Controls, and Procurement Fraud Schemes

    Science.gov (United States)

    2013-06-01

    United States COR Contracting Officer Representative COSO Committee of Sponsoring Organizations DAU Defense Acquisition University DAWIA Defense...adopted from the Committee of Sponsoring Organizations of the Treadway Commission ( COSO ) (1992). There are five components: control environment, risk...the positive values for the organization and at the same time respond quickly to any inappropriate action ( COSO , 1992). This sets the boundaries for

  2. Synchronization and Desynchronizing Control Schemes for Supermarket Refrigeration Systems

    DEFF Research Database (Denmark)

    Larsen, Lars Finn Sloth; Thybo, Claus Thybo; Izadi-Zamanabadi, Roozbeh

    2007-01-01

    A supermarket refrigeration system is a hybrid system with switched nonlinear dynamics and discrete-valued input variables such as opening/closing of valves and start/stop of compressors. Practical and simulation studies have shown that the use of distributed hysteresis controllers to operate...

  3. Performance analysis of joint diversity combining, adaptive modulation, and power control schemes

    KAUST Repository

    Qaraqe, Khalid A.

    2011-01-01

    Adaptive modulation and diversity combining represent very important adaptive solutions for future generations of wireless communication systems. Indeed, in order to improve the performance and the efficiency of these systems, these two techniques have been recently used jointly in new schemes named joint adaptive modulation and diversity combining (JAMDC) schemes. Considering the problem of finding low hardware complexity, bandwidth-efficient, and processing-power efficient transmission schemes for a downlink scenario and capitalizing on some of these recently proposed JAMDC schemes, we propose and analyze in this paper three joint adaptive modulation, diversity combining, and power control (JAMDCPC) schemes where a constant-power variable-rate adaptive modulation technique is used with an adaptive diversity combining scheme and a common power control process. More specifically, the modulation constellation size, the number of combined diversity paths, and the needed power level are jointly determined to achieve the highest spectral efficiency with the lowest possible processing power consumption quantified in terms of the average number of combined paths, given the fading channel conditions and the required bit error rate (BER) performance. In this paper, the performance of these three JAMDCPC schemes is analyzed in terms of their spectral efficiency, processing power consumption, and error-rate performance. Selected numerical examples show that these schemes considerably increase the spectral efficiency of the existing JAMDC schemes with a slight increase in the average number of combined paths for the low signal-to-noise ratio range while maintaining compliance with the BER performance and a low radiated power which yields to a substantial decrease in interference to co-existing users and systems. © 2011 IEEE.

  4. Development of Vision Control Scheme of Extended Kalman filtering for Robot's Position Control

    International Nuclear Information System (INIS)

    Jang, W. S.; Kim, K. S.; Park, S. I.; Kim, K. Y.

    2003-01-01

    It is very important to reduce the computational time in estimating the parameters of vision control algorithm for robot's position control in real time. Unfortunately, the batch estimation commonly used requires too murk computational time because it is iteration method. So, the batch estimation has difficulty for robot's position control in real time. On the other hand, the Extended Kalman Filtering(EKF) has many advantages to calculate the parameters of vision system in that it is a simple and efficient recursive procedures. Thus, this study is to develop the EKF algorithm for the robot's vision control in real time. The vision system model used in this study involves six parameters to account for the inner(orientation, focal length etc) and outer (the relative location between robot and camera) parameters of camera. Then, EKF has been first applied to estimate these parameters, and then with these estimated parameters, also to estimate the robot's joint angles used for robot's operation. finally, the practicality of vision control scheme based on the EKF has been experimentally verified by performing the robot's position control

  5. A novel and efficient user access control scheme for wireless body area sensor networks

    Directory of Open Access Journals (Sweden)

    Santanu Chatterjee

    2014-07-01

    Full Text Available Wireless body area networks (WBANs can be applied to provide healthcare and patient monitoring. However, patient privacy can be vulnerable in a WBAN unless security is considered. Access to authorized users for the correct information and resources for different services can be provided with the help of efficient user access control mechanisms. This paper proposes a new user access control scheme for a WBAN. The proposed scheme makes use of a group-based user access ID, an access privilege mask, and a password. An elliptic curve cryptography-based public key cryptosystem is used to ensure that a particular legitimate user can only access the information for which he/she is authorized. We show that our scheme performs better than previously existing user access control schemes. Through a security analysis, we show that our scheme is secure against possible known attacks. Furthermore, through a formal security verification using the AVISPA (Automated Validation of Internet Security Protocols and Applications tool, we show that our scheme is also secure against passive and active attacks.

  6. PLS-based memory control scheme for enhanced process monitoring

    KAUST Repository

    Harrou, Fouzi

    2017-01-20

    Fault detection is important for safe operation of various modern engineering systems. Partial least square (PLS) has been widely used in monitoring highly correlated process variables. Conventional PLS-based methods, nevertheless, often fail to detect incipient faults. In this paper, we develop new PLS-based monitoring chart, combining PLS with multivariate memory control chart, the multivariate exponentially weighted moving average (MEWMA) monitoring chart. The MEWMA are sensitive to incipient faults in the process mean, which significantly improves the performance of PLS methods and widen their applicability in practice. Using simulated distillation column data, we demonstrate that the proposed PLS-based MEWMA control chart is more effective in detecting incipient fault in the mean of the multivariate process variables, and outperform the conventional PLS-based monitoring charts.

  7. A unified numerical scheme for linear-quadratic optimal control problems with joint control and state constraints

    NARCIS (Netherlands)

    Han, Lanshan; Camlibel, M. Kanat; Pang, Jong-Shi; Heemels, W. P. Maurice H.

    2012-01-01

    This paper presents a numerical scheme for solving the continuous-time convex linear-quadratic (LQ) optimal control problem with mixed polyhedral state and control constraints. Unifying a discretization of this optimal control problem as often employed in model predictive control and that obtained

  8. Designing an object-oriented scheme for accelerator equipment control

    International Nuclear Information System (INIS)

    Trofimov, N.N.

    1994-01-01

    The object-oriented analysis (OOA) and design (OOD) formalisms developed by Project Technology Inc. is presented in this report. The method was originated in 1979 with the analysis phase of a large real-time project at Lawrence Berkeley Laboratory and since that time has been used in several large-scale industrial projects. It is supported by the Teamwork CASE package from Cadre Technologies Inc. For introducing basic concepts and definitions of the OOA/OOD, a typical accelerator device example: remotely controllable power supply which is used to power magnets in an accelerator beam transfer line is used through out this report. 18 refs., 18 figs

  9. Performance Comparison of Grid-Faulty Control Schemes for Inverter-Based Industrial Microgrids

    Directory of Open Access Journals (Sweden)

    Antonio Camacho

    2017-12-01

    Full Text Available Several control schemes specifically designed to operate inverter-based industrial microgrids during voltage sags have been recently proposed. This paper first classifies these control schemes in three categories and then performs a comparative analysis of them. Representative control schemes of each category are selected, described and used to identify the main features and performance of the considered category. The comparison is based on the evaluation of several indexes, which measure the power quality of the installation and utility grid during voltage sags, including voltage regulation, reactive current injection and transient response. The paper includes selected simulation results from a 500 kVA industrial microgrid to validate the expected features of the considered control schemes. Finally, in view of the obtained results, the paper proposes an alternative solution to cope with voltage sags, which includes the use of a static compensator in parallel with the microgrid. The novelty of this proposal is the suitable selection of the control schemes for both the microgrid and the static compensator. The superior performance of the proposal is confirmed by the analysis of the quality indexes. Its practical limitations are also revealed, showing that the topic studied in this paper is still open for further research.

  10. Digital IP Protection Using Threshold Voltage Control

    OpenAIRE

    Davis, Joseph; Kulkarni, Niranjan; Yang, Jinghua; Dengi, Aykut; Vrudhula, Sarma

    2016-01-01

    This paper proposes a method to completely hide the functionality of a digital standard cell. This is accomplished by a differential threshold logic gate (TLG). A TLG with $n$ inputs implements a subset of Boolean functions of $n$ variables that are linear threshold functions. The output of such a gate is one if and only if an integer weighted linear arithmetic sum of the inputs equals or exceeds a given integer threshold. We present a novel architecture of a TLG that not only allows a single...

  11. Adaptive Test Schemes for Control of Paratuberculosis in Dairy Cows

    DEFF Research Database (Denmark)

    Kirkeby, Carsten Thure; Græsbøll, Kaare; Nielsen, Søren Saxmose

    2016-01-01

    consequences of continuously adapting the sampling interval in response to the estimated true prevalence in the herd. The key results were that the true prevalence was greatly affected by the hygiene level and to some extent by the test-frequency. Furthermore, the choice of prevalence that will be tolerated...... through a variety of test-strategies, but are challenged by the lack of perfect tests. Frequent testing increases the sensitivity but the costs of testing are a cause of concern for farmers. Here, we used a herd simulation model using milk ELISA tests to evaluate the epidemiological and economic...... in a control scenario had a major impact on the true prevalence in the normal hygiene setting, but less so when the hygiene was poor. The net revenue is not greatly affected by the test-strategy, because of the general variation in net revenues between farms. An exception to this is the low hygiene herd, where...

  12. A Novel, Automatic Quality Control Scheme for Real Time Image Transmission

    Directory of Open Access Journals (Sweden)

    S. Ramachandran

    2002-01-01

    Full Text Available A novel scheme to compute energy on-the-fly and thereby control the quality of the image frames dynamically is presented along with its FPGA implementation. This scheme is suitable for incorporation in image compression systems such as video encoders. In this new scheme, processing is automatically stopped when the desired quality is achieved for the image being processed by using a concept called pruning. Pruning also increases the processing speed by a factor of more than two when compared to the conventional method of processing without pruning. An MPEG-2 encoder implemented using this scheme is capable of processing good quality monochrome and color images of sizes up to 1024 × 768 pixels at the rate of 42 and 28 frames per second, respectively, with a compression ratio of over 17:1. The encoder is also capable of working in the fixed pruning level mode with user programmable features.

  13. A circuit scheme to control current surge for RFID-NVM pumps

    International Nuclear Information System (INIS)

    Li Ming; Kang Jinfeng; Wang Yangyuan; Yang Liwu

    2010-01-01

    This paper presents a new circuit scheme to control the current surge in the boosting phase of an radio frequency idenfication-nonvolative memory pump. By introducing a circuit block consisting of a current reference and a current mirror, the new circuit scheme can keep the period-average current of the pump constantly below the desired level, for example, 2.5 μA. Therefore, it can prevent the rectified supply of the RFID tag IC from collapsing in the boosting phase of the pump. The presented scheme could effectively reduce the voltage drop on the rectified supply from more than 50% to even zero, but could cost less area. Moreover, an analytical expression to calculate the boosting time of a pump in the new scheme is developed. (semiconductor integrated circuits)

  14. Comparative Study between Two Schemes of Active-Control-Based Mechatronic Inerter

    Directory of Open Access Journals (Sweden)

    He Lingduo

    2017-01-01

    Full Text Available Based on force-current analogy and velocity-voltage analogy in the theory of electromechanical analogy, the inerter is a device that corresponded to the capacitor completely where conquers the nature restriction of mass, what’s more, it is significant to improve the ratio of the inerter’s inertance to its mass for mechanical networks synthesis. And according to the principle of active-control-based mechatronic inerter, we present two implementation schemes. One was based on linear motor, and the other was based on the ball screw and rotary motor. We introduced the implementation methods and established theoretical model of the two schemes, then compared the ratio of the inerter’s inertance to its mass for the two schemes. Finally, we consider the scheme is better which was based on the ball screw and rotary motor.

  15. Adaptive control schemes for improving dynamic performance of efficiency-optimized induction motor drives.

    Science.gov (United States)

    Kumar, Navneet; Raj Chelliah, Thanga; Srivastava, S P

    2015-07-01

    Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) for controlling the excitation of motor in accordance with torque and speed. MBC offers energy conservation especially at part-load operation, but it creates ripples in torque and speed during load transition, leading to poor dynamic performance of the drive. This study investigates the opportunity for improving dynamic performance of a three-phase IM operating with MBC and proposes three control schemes: (i) MBC with a low pass filter (ii) torque producing current (iqs) injection in the output of speed controller (iii) Variable Structure Speed Controller (VSSC). The pre and post operation of MBC during load transition is also analyzed. The dynamic performance of a 1-hp, three-phase squirrel-cage IM with mine-hoist load diagram is tested. Test results are provided for the conventional field-oriented (constant flux) control and MBC (adjustable excitation) with proposed schemes. The effectiveness of proposed schemes is also illustrated for parametric variations. The test results and subsequent analysis confer that the motor dynamics improves significantly with all three proposed schemes in terms of overshoot/undershoot peak amplitude of torque and DC link power in addition to energy saving during load transitions. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  16. End-point parametrization and guaranteed stability for a model predictive control scheme

    NARCIS (Netherlands)

    Weiland, Siep; Stoorvogel, Antonie Arij; Tiagounov, Andrei A.

    2001-01-01

    In this paper we consider the closed-loop asymptotic stability of the model predictive control scheme which involves the minimization of a quadratic criterion with a varying weight on the end-point state. In particular, we investigate the stability properties of the (MPC-) controlled system as

  17. Multichannel feedforward control schemes with coupling compensation for active sound profiling

    Science.gov (United States)

    Mosquera-Sánchez, Jaime A.; Desmet, Wim; de Oliveira, Leopoldo P. R.

    2017-05-01

    Active sound profiling includes a number of control techniques that enables the equalization, rather than the mere reduction, of acoustic noise. Challenges may rise when trying to achieve distinct targeted sound profiles simultaneously at multiple locations, e.g., within a vehicle cabin. This paper introduces distributed multichannel control schemes for independently tailoring structural borne sound reaching a number of locations within a cavity. The proposed techniques address the cross interactions amongst feedforward active sound profiling units, which compensate for interferences of the primary sound at each location of interest by exchanging run-time data amongst the control units, while attaining the desired control targets. Computational complexity, convergence, and stability of the proposed multichannel schemes are examined in light of the physical system at which they are implemented. The tuning performance of the proposed algorithms is benchmarked with the centralized and pure-decentralized control schemes through computer simulations on a simplified numerical model, which has also been subjected to plant magnitude variations. Provided that the representation of the plant is accurate enough, the proposed multichannel control schemes have been shown as the only ones that properly deliver targeted active sound profiling tasks at each error sensor location. Experimental results in a 1:3-scaled vehicle mock-up further demonstrate that the proposed schemes are able to attain reductions of more than 60 dB upon periodic disturbances at a number of positions, while resolving cross-channel interferences. Moreover, when the sensor/actuator placement is found as defective at a given frequency, the inclusion of a regularization parameter in the cost function is seen to not hinder the proper operation of the proposed compensation schemes, at the time that it assures their stability, at the expense of losing control performance.

  18. Comparison of Different Control Schemes for Strategic Departure Metering

    Science.gov (United States)

    Idris, Husni; Shen, Ni; Saraf, Aditya; Bertino, Jason; Zelinski, Shannon

    2016-01-01

    Airports and their terminal airspaces are key choke points in the air transportation system causing major delays and adding to pollution. A solution aimed at mitigating these chokepoints integrates the scheduling of runway operations, flight release from the gates and ramp into the airport movement area, and merging with other traffic competing for downstream airspace points. Within this integrated concept, we present a simulation-based analysis of the departure metering process, which delays the release of flights into the airport movement area while balancing two competing objectives: (1) maintaining large enough queues at the airport resources to maximize throughput and (2) absorbing excess delays at the gates or in ramp areas to save on fuel consumption, emissions, noise, and passenger discomfort. Three metering strategies are compared which respectively attempt to control the number of flights that (1) left the gate but did not take off, (2) left the ramp but did not take off, and (3) spent their unimpeded transit time to the runway but did not take off. It was observed that under deterministic and demand uncertainty conditions, the first strategy performed better than the other two strategies in terms of maintaining the runway throughput while transferring a significant average delay of two minutes to the gate. On the other hand, under uncertainties of flight transit time and runway service rate, all the strategies struggled to delay flights at the gate without a significant impact on the runway throughput.

  19. Development of a control scheme of homodyne detection for extracting ponderomotive squeezing from a Michelson interferometer

    International Nuclear Information System (INIS)

    Sakata, Shihori; Kawamura, Seiji; Sato, Shuichi; Somiya, Kentaro; Arai, Koji; Fukushima, Mitsuhiro; Sugamoto, Akio

    2006-01-01

    We developed a control scheme of homodyne detection. To operate the homodyne detector as easy as possible, a simple Michelson interferometer is used. Here a motivation that the control scheme of the homodyne detection is developed is for our future experiment of extracting the ponderomotively squeezed vacuum fluctuations. To obtain the best signalto- noise ratio using the homodyne detection, the homodyne phase should be optimized. The optimization of the homodyne phase is performed by changing a phase of a local oscillator for the homodyne detection from a point at which a signal is maximized. In fact, in this experiment, using the developed control scheme, we locked the Michelson interferometer with the homodyne detector and changed the phase of the local oscillator for the homodyne detection. Then, we measured signals quantity changed by changing the phase of the local oscillator for the homodyne detection. Here we used the output from the homodyne detection as the signal

  20. Using a digital signal processor as a data stream controller for digital subtraction angiography

    International Nuclear Information System (INIS)

    Meng, J.D.; Katz, J.E.

    1991-10-01

    High speed, flexibility, and good arithmetic abilities make digital signal processors (DSP) a good choice as input/output controllers for real time applications. The DSP can be made to pre-process data in real time to reduce data volume, to open early windows on what is being acquired and to implement local servo loops. We present an example of a DSP as an input/output controller for a digital subtraction angiographic imaging system. The DSP pre-processes the raw data, reducing data volume by a factor of two, and is potentially capable of producing real-time subtracted images for immediate display

  1. HYBRID SYSTEM BASED FUZZY-PID CONTROL SCHEMES FOR UNPREDICTABLE PROCESS

    Directory of Open Access Journals (Sweden)

    M.K. Tan

    2011-07-01

    Full Text Available In general, the primary aim of polymerization industry is to enhance the process operation in order to obtain high quality and purity product. However, a sudden and large amount of heat will be released rapidly during the mixing process of two reactants, i.e. phenol and formalin due to its exothermic behavior. The unpredictable heat will cause deviation of process temperature and hence affect the quality of the product. Therefore, it is vital to control the process temperature during the polymerization. In the modern industry, fuzzy logic is commonly used to auto-tune PID controller to control the process temperature. However, this method needs an experienced operator to fine tune the fuzzy membership function and universe of discourse via trial and error approach. Hence, the setting of fuzzy inference system might not be accurate due to the human errors. Besides that, control of the process can be challenging due to the rapid changes in the plant parameters which will increase the process complexity. This paper proposes an optimization scheme using hybrid of Q-learning (QL and genetic algorithm (GA to optimize the fuzzy membership function in order to allow the conventional fuzzy-PID controller to control the process temperature more effectively. The performances of the proposed optimization scheme are compared with the existing fuzzy-PID scheme. The results show that the proposed optimization scheme is able to control the process temperature more effectively even if disturbance is introduced.

  2. Physical control oriented model of large scale refrigerators to synthesize advanced control schemes. Design, validation, and first control results

    Science.gov (United States)

    Bonne, François; Alamir, Mazen; Bonnay, Patrick

    2014-01-01

    In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO.

  3. SIMULACIÓN DE CONTROLADORES DIGITALES SIMULATION OF DIGITAL CONTROLLERS

    Directory of Open Access Journals (Sweden)

    Carlos Álvarez G

    2009-12-01

    Full Text Available El presente trabajo tiene como objetivo la implementación de controladores digitales en un entorno de simulación controlado, para esto se desarrolla una plataforma de hardware que permite ejecutar los programas en lenguaje C generados en una estación de trabajo. Estos programas corresponden al controlador y a la planta que son generados por un software que genera dichos programas a partir de sus parámetros de modelación aplicando teoría de control digital sobre procesos reales.This paper describes an implementation of digital controllers in a simulation environment for including a hardware platform for running programs generated on a workstation. These programs for both the controller and the plant are generated by software based on parameters using digital control theory for real processes.

  4. MAS2-8 radar and digital control unit

    Science.gov (United States)

    Oberg, J. M.; Ulaby, F. T.

    1974-01-01

    The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented.

  5. An improved current control scheme for grid-connected DG unit based distribution system harmonic compensation

    DEFF Research Database (Denmark)

    He, Jinwei; Wei Li, Yun; Wang, Xiongfei

    2013-01-01

    In order to utilize DG unit interfacing converters to actively compensate distribution system harmonics, this paper proposes an enhanced current control approach. It seamlessly integrates system harmonic mitigation capabilities with the primary DG power generation function. As the proposed current...... the fundamental current reference. The proposed power control scheme effectively eliminates the impacts of steady-state fundamental current tracking errors in the DG units. Thus, an accurate power control is realized even when the harmonic compensation functions are activated. Experimental results from a single...... controller has two well decoupled control branches to independently control fundamental and harmonic DG currents, phase-locked loops (PLL) and system harmonic component extractions can be avoided during system harmonic compensation. Moreover, a closed-loop power control scheme is also employed to derive...

  6. Bus-oriented digital control techniques in nuclear power plants

    International Nuclear Information System (INIS)

    Salm, M.

    1987-01-01

    The author states the conservative principles which govern the authorization procedures for nuclear reactor control systems. Using the example of a feedwater supply regulator, employing a digital, bus-oriented control system, he describes how the stigma attached to the word nuclear can be alleviated. (G.T.H.)

  7. Digital Sliding Mode Control of Anti-Lock Braking System

    Directory of Open Access Journals (Sweden)

    MITIC, D. B.

    2013-02-01

    Full Text Available The control of anti-lock braking system is a great challenge, because of the nonlinear and complex characteristics of braking dynamics, unknown parameters of vehicle environment and system parameter variations. Using some of robust control methods, such as sliding mode control, can be a right solution for these problems. In this paper, we introduce a novel approach to design of ABS controllers, which is based on digital sliding mode control with only input/output measurements. The relay term of the proposed digital sliding mode control is filtered through digital integrator, reducing the chattering phenomenon in that way, and the additional signal of estimated modelling error is introduced into control algorithm to enhance the system steady-state accuracy. The given solution was verified in real experimental framework and the obtained results were compared with the results of implementation of two other digital sliding mode control algorithms. It is shown that it gives better system response, higher steady-state accuracy and smaller chattering.

  8. Nonlinear H∞ Optimal Control Scheme for an Underwater Vehicle with Regional Function Formulation

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2013-01-01

    Full Text Available A conventional region control technique cannot meet the demands for an accurate tracking performance in view of its inability to accommodate highly nonlinear system dynamics, imprecise hydrodynamic coefficients, and external disturbances. In this paper, a robust technique is presented for an Autonomous Underwater Vehicle (AUV with region tracking function. Within this control scheme, nonlinear H∞ and region based control schemes are used. A Lyapunov-like function is presented for stability analysis of the proposed control law. Numerical simulations are presented to demonstrate the performance of the proposed tracking control of the AUV. It is shown that the proposed control law is robust against parameter uncertainties, external disturbances, and nonlinearities and it leads to uniform ultimate boundedness of the region tracking error.

  9. A New Pricing Scheme for Controlling Energy Storage Devices in Future Smart Grid

    Directory of Open Access Journals (Sweden)

    Jingwei Zhu

    2014-01-01

    Full Text Available Improvement of the overall efficiency of energy infrastructure is one of the main anticipated benefits of the deployment of smart grid technology. Advancement in energy storage technology and two-way communication in the electric network are indispensable components to achieve such a vision, while efficient pricing schemes and appropriate storage management are also essential. In this paper, we propose a universal pricing scheme which permits one to indirectly control the energy storage devices in the grid to achieve a more desirable aggregate demand profile that meets a particular target of the grid operator such as energy generation cost minimization and carbon emission reduction. Such a pricing scheme can potentially be applied to control the behavior of energy storage devices installed for integration of intermittent renewable energy sources that have permission to grid connection and will have broader applications as an increasing number of novel and low-cost energy storage technologies emerge.

  10. A Power System Emergency Control Scheme in the Presence of High Wind Power Penetration

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar

    of grids with a high penetration of renewable energies makes it difficult to overseen and overcome widespread range of combinational and cascading events, just by relying on conventional protection systems, which generally do no coordinate the different grid variables in the respective protection schemes...... from distant units to the incidence place. In this thesis, localization of both load-frequency control an load shedding are fulfilled using locally measured voltage drop data in the decentralized control strategy. The proposed load shedding scheme is coordinated with existing plant protection relays......The main goal of the project is to improve existing protection technology by localizing the load shedding scheme in grids with high share of dispersed generation dominantly provided by renewable energy sources, i.e. wind, wave, solar, biomass, etc. The higher complexity and lower predictability...

  11. A Digital Self Excited Loop for Accelerating Cavity Field Control

    International Nuclear Information System (INIS)

    Curt Hovater; Trent Allison; Jean Delayen; John Musson; Tomasz Plawski

    2007-01-01

    We have developed a digital process that emulates an analog oscillator and ultimately a self excited loop (SEL) for field control. The SEL, in its analog form, has been used for many years for accelerating cavity field control. In essence the SEL uses the cavity as a resonant circuit -- much like a resonant (tank) circuit is used to build an oscillator. An oscillating resonant circuit can be forced to oscillate at different, but close, frequencies to resonance by applying a phase shift in the feedback path. This allows the circuit to be phased-locked to a master reference, which is crucial for multiple cavity accelerators. For phase and amplitude control the SEL must be forced to the master reference frequency, and feedback provided for in both dimensions. The novelty of this design is in the way digital signal processing (DSP) is structured to emulate an analog system. While the digital signal processing elements are not new, to our knowledge this is the first time that the digital SEL concept has been designed and demonstrated. This paper reports on the progress of the design and implementation of the digital SEL for field control of superconducting accelerating cavities

  12. A novel dual closed-loop control scheme based on repetitive control for grid-connected inverters with an LCL filter.

    Science.gov (United States)

    Gao, Yun-Guang; Jiang, Fa-Yang; Song, Jian-Cheng; Zheng, Li-Jun; Tian, Fei-Yan; Geng, Pu-Long

    2018-03-01

    Grid-connected inverters with LCL filters need high steady-state control accuracy, fast dynamic response performance, and strong robustness to guarantee the power quality. However, there are many problems in traditional control strategies that restrict improvements to control system performance, such as poor dynamic performance of traditional single-repetitive control, large ripples, low steady-state accuracy of inverter current feedback based repetitive dual-loop control or grid-current feedback based single-loop proportional-integral control. In this paper, a novel dual closed-loop repetitive control strategy based on grid current feedback is proposed for single-phase grid-connected inverters with LCL filters. The proportional-integral inner loop is stabilized by using an inherent one-beat delay achieved by digital controller. Based on the inner loop system, a detailed design scheme of a repetitive controller is presented, through which direct control of the grid current is realized, the reference is tracked perfectly to a zero phase shift, and high-attenuation gain is achieved in the high frequency range. In particular, the gird-voltage feed forward control and current reference feedforward control are adopted to suppress grid-voltage disturbance and increase dynamic tracking performance. Finally, the simulation and experimental results show that the proposed method has the advantages of high steady-state accuracy, fast dynamic response, and anti-disturbance ability. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Distributed digital real-time control system for the TCV tokamak and its applications

    Science.gov (United States)

    Anand, H.; Galperti, C.; Coda, S.; Duval, B. P.; Felici, F.; Blanken, T.; Maljaars, E.; Moret, J.-M.; Sauter, O.; Goodman, T. P.; Kim, D.

    2017-05-01

    A key feature of the new digital plasma control system installed on the TCV (Tokamak à Configuration Variable) tokamak is its possibility to rapidly design, test and deploy real-time algorithms. It accommodates hundreds of diagnostic inputs and actuator outputs, and offers the possibility to design advanced control algorithms with better knowledge of the plasma state and to coherently control all TCV actuators, including poloidal field coils, gas valves, the gyrotron powers and launcher angles of the electron cyclotron heating and current drive system together with diagnostic triggering signals. It encompasses plasma control applications ranging from basic experiments of coil current and density control to advanced experiments of magnetohydrodynamics (MHD) and plasma profile control. The system consists of multiple nodes, each of which may have a local analog to digital (ADC) and/or digital to analog (DAC) card; all nodes are connected to a reflective memory (RFM), providing a deterministic method of sharing memory between them. Recently, a generalized plasma position and shape controller based on the real-time (RT) Grad-Shafranov solver RTLIUQE was developed and implemented, providing the basis for future high performance plasma operation with advanced plasma configurations. The controller design is based on an isoflux control scheme and utilizes singular value decomposition (SVD), to respect the limits on poloidal field coils currents by limiting the controlled parameters to the set that can be more easily controlled. The controller is capable in principle of providing improved equilibrium control especially for unconventional plasma scenarios, for e.g. reliable control of ‘snowflake’ equilibria with closely spaced x-points, i.e. the ‘exact’ snowflake, and the development of negative triangularity plasmas in H-mode. An addition of a new node on the digital control system has enhanced the real time computational capacity and hosts the real-time transport

  14. A digital controller for the Omega West Reactor

    International Nuclear Information System (INIS)

    Minor, M.M.; Kaufman, M.D.; Smith, T.W.

    1992-05-01

    A new nuclear reactor control system for the Omega West Reactor (OWR) has been designed to replace the aging and hard to maintain controller presently installed. The controller uses single board computers, digital and analog input and output modules, and stepping motor indexers installed on a standard bus (VME bus). The eight poison control rod drive motors are replaced with stepping motors. The control algorithm for the OWR was not changed in order to expedite approval for installation. This report presents the results of the development of the new control system. Included in the report are copies of some of the software that drives the new controller

  15. Stress testing of digital flight-control system software

    Science.gov (United States)

    Rajan, N.; Defeo, P. V.; Saito, J.

    1983-01-01

    A technique for dynamically testing digital flight-control system software on a module-by-module basis is described. Each test module is repetitively executed faster than real-time with an exhaustive input sequence. Outputs of the test module are compared with outputs generated by an alternate, simpler implementation for the same input data. Discrepancies between the two sets of output indicate the possible presence of a software error. The results of an implementation of this technique in the Digital Flight-Control System Software Verification Laboratory are discussed.

  16. A new direct torque control scheme for induction motors using linear state feedback

    Energy Technology Data Exchange (ETDEWEB)

    Kandianis, A.; Manias, S.N. [National Technical Univ. of Athens (Greece). Dept. of Electrical Engineering; Griva, G.; Profumo, F. [Politecnico di Torino (Italy). Dept. of Electrical Engineering

    1995-12-31

    In this paper a new Direct Torque Control (DTC) scheme for induction motor drives is described, based on the linear state feedback method with dynamic output feedback. The DTC has been shown to be a good solution in torque controlled drives applications when the speed control is not required (e.g. traction drives for electric vehicles). In such cases, the torque command comes directly from the user input. By considering the torque and flux as the outputs of the linearized motor model, it is possible to design an optimum controller with constant gain state feedback and dynamic output feedback through an integral term. The design procedure of the proposed control scheme is described and the simulation results are presented to show the overall performance of the system.

  17. Neural Computation Scheme of Compound Control: Tacit Learning for Bipedal Locomotion

    Science.gov (United States)

    Shimoda, Shingo; Kimura, Hidenori

    The growing need for controlling complex behaviors of versatile robots working in unpredictable environment has revealed the fundamental limitation of model-based control strategy that requires precise models of robots and environments before their operations. This difficulty is fundamental and has the same root with the well-known frame problem in artificial intelligence. It has been a central long standing issue in advanced robotics, as well as machine intelligence, to find a prospective clue to attack this fundamental difficulty. The general consensus shared by many leading researchers in the related field is that the body plays an important role in acquiring intelligence that can conquer unknowns. In particular, purposeful behaviors emerge during body-environment interactions with the help of an appropriately organized neural computational scheme that can exploit what the environment can afford. Along this line, we propose a new scheme of neural computation based on compound control which represents a typical feature of biological controls. This scheme is based on classical neuron models with local rules that can create macroscopic purposeful behaviors. This scheme is applied to a bipedal robot and generates the rhythm of walking without any model of robot dynamics and environments.

  18. Hierarchical predictive control scheme for distributed energy storage integrated with residential demand and photovoltaic generation

    NARCIS (Netherlands)

    Lampropoulos, I.; Garoufalis, P.; van den Bosch, P.P.J.; Kling, W.L.

    2015-01-01

    A hierarchical control scheme is defined for the energy management of a battery energy storage system which is integrated in a low-voltage distribution grid with residential customers and photovoltaic installations. The scope is the economic optimisation of the integrated system by employing

  19. Design, implementation and testing of a fuzzy control scheme for laser welding

    NARCIS (Netherlands)

    Jauregui Becker, Juan Manuel; Aalderink, B.J.; Aalderink, Benno; Aarts, Ronald G.K.M.; Olde Benneker, Jeroen; Meijer, J.

    2008-01-01

    A fuzzy logic controller (FLC) scheme has been developed for laser welding. Process light emissions are measured and combined to determine the current status of the welding process. If the process is not in a desired welding state, the FLC will adapt the laser power. The FLC has been demonstrated

  20. Control Strategies for Islanded Microgrid using Enhanced Hierarchical Control Structure with Multiple Current-Loop Damping Schemes

    DEFF Research Database (Denmark)

    Han, Yang; Shen, Pan; Zhao, Xin

    2017-01-01

    In this paper, the modeling, controller design, and stability analysis of the islanded microgrid (MG) using enhanced hierarchical control structure with multiple current loop damping schemes is proposed. The islanded MG is consisted of the parallel-connected voltage source inverters using LCL...

  1. A decentralized control scheme for an effective coordination of phasic and tonic control in a snake-like robot

    International Nuclear Information System (INIS)

    Sato, Takahide; Kano, Takeshi; Ishiguro, Akio

    2012-01-01

    Autonomous decentralized control has attracted considerable attention because it enables us to understand the adaptive and versatile locomotion of animals and facilitates the construction of truly intelligent artificial agents. Thus far, we have developed a snake-like robot (HAUBOT I) that is driven by a decentralized control scheme based on a discrepancy function, which incorporates phasic control. In this paper, we investigate a decentralized control scheme in which phasic and tonic control are well coordinated, as an extension of our previous study. To verify the validity of the proposed control scheme, we apply it to a snake-like robot (HAUBOT II) that can adjust both the phase relationship between its body segments and the stiffness at each joint. The results indicate that the proposed control scheme enables the robot to exhibit remarkable real-time adaptability over various frictional and inclined terrains. These findings can potentially enable us to gain a deeper insight into the autonomous decentralized control mechanism underlying the adaptive and resilient locomotion of animals.

  2. The task of control digital image compression

    OpenAIRE

    TASHMANOV E.B.; МАМАTOV М.S.

    2014-01-01

    In this paper we consider the relationship of control tasks and image compression losses. The main idea of this approach is to allocate structural lines simplified image and further compress the selected data

  3. An auto-bias control scheme for IQ-modulator with various modulation formats

    Science.gov (United States)

    Zhang, Wenqi; Yuan, Xueguang; Zhang, Yang'an

    2016-10-01

    We propose and demonstrate an auto-bias control scheme for the IQ-modulator of a flexible optical PSK or QAM or other modulation formats transmitter in this paper. Due to IQ-modulators usually producing higher-order modulation format, these modulation formats involve phase mostly. It is based on that the bias drift will change the operating point and result in varying the output optical phase. This technology has no restrictions on modulation formats, so it has good flexibility. The experimental result show the three biases can be stabilized when the proposed scheme is implemented.

  4. Digital Speed Cascade Control, using Scilab / Xcos Environment

    Directory of Open Access Journals (Sweden)

    Petru Chioncel

    2016-10-01

    Full Text Available This paper presents an application of digital cascade control implemented in Scilab / Xcos environment, using a P type regulator for the position adjustment circuit, a PI controller for the speed circuit adjustment; the current respectively moments control circuits are rendered by elements of PT1 type. On this basis the program is done in Scilab and the related signal block diagram implemented in Xcos; through simulation, the step response of the system is analyzed for different sampling times.

  5. Study on Control Scheme for the Inverters in Low Voltage Microgrid with Nonlinear Loads

    Science.gov (United States)

    Xu, Jiqiang; Lu, Wenzhou; Wu, Lei

    2017-05-01

    There are a lot of nonlinear loads in real low voltage microgrid system. It will cause serious output voltage and grid current harmonic distortions problems in island and grid-connected modes, respectively. To solve this problem, this paper proposes a droop control scheme with quasi-proportion and resonant (quasi-PR) controller based on αβ stationary reference frame to make microgrid smoothly switch between grid-connected and island modes without changing control method. Moreover, in island mode, not only stable output voltage and frequency, but also reduced output voltage harmonics with added nonlinear loads can be achieved; In grid-connected mode, not only constant power, but also reduced grid current harmonics can be achieved. Simulation results verify the effectiveness of the proposed control scheme.

  6. A Reconfiguration Control Scheme for a Quadrotor Helicopter via Combined Multiple Models

    Directory of Open Access Journals (Sweden)

    Fuyang Chen

    2014-08-01

    Full Text Available In this paper, an optimal reconfiguration control scheme is proposed for a quadrotor helicopter with actuator faults via adaptive control and combined multiple models. The combined models set contains several fixed models, an adaptive model and a reinitialized adaptive model. The fixed models and the adaptive model can describe the failure system under different fault conditions. Moreover, the proposed reinitialized adaptive model refers to the closest model of the current system and can improve the speed of convergence effectively. In addition, the reference model is designed in consideration of an optimal control performance index and the principle of the minimum cost to achieve perfect tracking performance. Finally, some simulation results demonstrate the effectiveness of the proposed reconfiguration control scheme for faulty cases.

  7. Identity driven Capability based Access Control (ICAC) Scheme for the Internet of Things

    DEFF Research Database (Denmark)

    Mahalle, Parikshit N.; Anggorojati, Bayu; Prasad, Neeli R.

    2012-01-01

    Internet of Things (IoT) becomes discretionary part of everyday life. Scalability and manageability is daunting due to unbounded number of devices and services. Access control and authorization in IoT with least privilege is equally important to establish secure communication between multiple...... devices and services. In this paper, the concept of capability for access control is introduced where the identities of the involved devices are entrenched in the access capabilities. Identity driven capability based access control (ICAC) scheme presented in this paper helps to alleviate issues related...... to complexity and dynamics of device identities. ICAC is implemented for 802.11 and results shows that ICAC has less scalability issues and better performance analysis compared with other access control schemes. The ICAC evaluation by using security protocol verification tool shows that ICAC is secure against...

  8. Digital feed back control for radial beam position

    International Nuclear Information System (INIS)

    Mestha, L.K.

    1989-09-01

    In the development of wide spread large scale distributed digital control systems, there is a requirement to automate small processes like radial beam control which will not only improve the beam quality but will also add local intelligence. Hence use is made here of digital control principles for such applications. The work concerned with the radial beam control discussed in this report has been developed for ISIS at RAL. The structure of the report is hence inclined more towards the local hardware system. The general feed back loop techniques can also be implemented for other control purpose. For instance, the author has successfully tested similar techniques to minimise the RF cavity tuning error, where the improvement in performance could not be matched by the analogue loop. A description of the RF cavity tuning programme and the associated experimental results will be published as a local paper for ISIS division. (author)

  9. Conversion of a servomanipulator from analog to digital control

    International Nuclear Information System (INIS)

    Killough, S.M.; Martin, H.L.; Hamel, W.R.

    1986-01-01

    Oak Ridge National Laboratory (ORNL) has developed expertise in computer control of force-reflecting master/slave servomanipulators as a result of research for the Consolidated Fuel Reprocessing Program. These computer control capabilities have been applied to a commercially available servomanipulator, the TeleOperator Systems SM-229. All of the servo drive and control circuitry has been replaced with commercially available digital controls and amplifiers, and a customer software - package has been developed at ORNL. This conversion to digital computer control resulted in significant improvements in force-reflection characteristics, ease of operation, diagnostic capabilities, indexing features, and potential increased reliability. The system will be used at the Tokamak Fusion Test Reactor at the Princeton Plasma Physics Laboratory (PPPL) for maintenance demonstrations

  10. An Effective Approach Control Scheme for the Tethered Space Robot System

    OpenAIRE

    Meng, Zhongjie; Huang, Panfeng

    2014-01-01

    The tethered space robot system (TSR), which is composed of a platform, a gripper and a space tether, has great potential in future space missions. Given the relative motion among the platform, tether, gripper and the target, an integrated approach model is derived. Then, a novel coordinated approach control scheme is presented, in which the tether tension, thrusters and the reaction wheel are all utilized. It contains the open-loop trajectory optimization, the feedback trajectory control and...

  11. Assessment of Digital Access Control Methods Used by Selected ...

    African Journals Online (AJOL)

    Assessment of Digital Access Control Methods Used by Selected Academic Libraries in South-West Nigeria. ... information professionals with the knowledge that would enable them establish an effective strategy to protect e-resources from such abuses as plagiarism, piracy and infringement of intellectual property rights.

  12. digital control of external devices through the parallel port

    African Journals Online (AJOL)

    2012-11-03

    Nov 3, 2012 ... Abstract. In this paper we carry out the digital control of external devices using the parallel port of a computer. The PC parallel port adapter that is specifically designed to attach printers has been found to be useful as a general input/output port for any device or application that matches its input/output ...

  13. Analysis and experimental verification of a control scheme for unified power quality conditioner

    Energy Technology Data Exchange (ETDEWEB)

    Peng Cheng Zhu; Xun Li; Yong Kang; Jian Chen [Huazhong Univ. of Science and Techmnology, Wuhan (China). Dept. of Electrical Engineering

    2005-07-01

    Improving power quality for sensitive load by a Unified Power Quality Conditioner (UPQC) in a distributed generation system is presented in this paper. The power balance of a UPQC, consisting of back-to-back connected series and shunt Active Filters (AF), is analysed. Based on the analysis a novel control scheme is established in a 2-phase Synchronous Rotating d-q Frame (SRF). In this control scheme, the series AF is controlled as a current source and makes the input current sinusoidal, while the shunt AF is controlled as a voltage source and keeps the load voltage in the normal value. With the proposed control strategy, the UPQC is capable of compensating not only harmonic and reactive currents of the load but also grid voltage distortion. There is no harmonic interference between harmonic-producing loads and harmonic-sensitive loads, which are connected on the common bus. The performance of a UPQC with the proposed control scheme under nonlinear load and grid voltage distortion is investigated with simulation as well as experimental works. (Author)

  14. Robot vision language RVL/V: An integration scheme of visual processing and manipulator control

    International Nuclear Information System (INIS)

    Matsushita, T.; Sato, T.; Hirai, S.

    1984-01-01

    RVL/V is a robot vision language designed to write a program for visual processing and manipulator control of a hand-eye system. This paper describes the design of RVL/V and the current implementation of the system. Visual processing is performed on one-dimensional range data of the object surface. Model-based instructions execute object detection, measurement and view control. The hierarchy of visual data and processing is introduced to give RVL/V generality. A new scheme to integrate visual information and manipulator control is proposed. The effectiveness of the model-based visual processing scheme based on profile data is demonstrated by a hand-eye experiment

  15. A Novel Rate Control Scheme for Constant Bit Rate Video Streaming

    Directory of Open Access Journals (Sweden)

    Venkata Phani Kumar M

    2015-08-01

    Full Text Available In this paper, a novel rate control mechanism is proposed for constant bit rate video streaming. The initial quantization parameter used for encoding a video sequence is determined using the average spatio-temporal complexity of the sequence, its resolution and the target bit rate. Simple linear estimation models are then used to predict the number of bits that would be necessary to encode a frame for a given complexity and quantization parameter. The experimental results demonstrate that our proposed rate control mechanism significantly outperforms the existing rate control scheme in the Joint Model (JM reference software in terms of Peak Signal to Noise Ratio (PSNR and consistent perceptual visual quality while achieving the target bit rate. Furthermore, the proposed scheme is validated through implementation on a miniature test-bed.

  16. A high-performance digital control system for TCV

    International Nuclear Information System (INIS)

    Lister, J.B.; Dutch, M.J.; Milne, P.G.; Means, R.W.

    1997-10-01

    The TCV hybrid analogue-digital plasma control system has been superseded by a high performance Digital Plasma Control System, DPCS, made possible by recent advances in off the shelf technology. We discuss the basic requirements for such a control system and present the design and specifications which were laid down. The nominal and final performances are presented and the complete design is given in detail. The integration of the new system into the current operation of the TCV tokamak is described. The procurement of this system has required close collaboration between the end-users and two commercial suppliers with one of the latter taking full responsibility for the system integration. The impact of this approach on the design and commissioning costs for the TCV project is presented. New possibilities offered by this new system are discussed, including possible work relevant to ITER plasma control development. (author) 3 figs., 5 refs

  17. Evaluation of Linear and Non-Linear Control Schemes Applied to a Hydraulic Servo System

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik Clemmensen

    2005-01-01

    is used as test facility acting as load for the hydraulic servo system. An experimentally verified non-linear model of the complete system has been developed and used to design a series of both linear and non-linear control schemes. The controllers from each category are compared with respect to design......Due to the innovation of low-cost electronics such as sensors, microcontrollers etc., the focus on highperformance motion control is increasing. This work focuses on position control of single-input single-output hydraulic servo-systems in general. A hydraulically actuated robotic manipulator...

  18. Evaluation of Linear and Non-Linear Control Schemes Applied to a Hydraulic Servo System

    DEFF Research Database (Denmark)

    Andersen, Torben Ole; Hansen, Michael Rygaard; Pedersen, Henrik Clemmensen

    2005-01-01

    Due to the innovation of low-cost electronics such as sensors, microcontrollers etc., the focus on highperformance motion control is increasing. This work focuses on position control of single-input single-output hydraulic servo-systems in general. A hydraulically actuated robotic manipulator...... is used as test facility acting as load for the hydraulic servo system. An experimentally verified non-linear model of the complete system has been developed and used to design a series of both linear and non-linear control schemes. The controllers from each category are compared with respect to design...

  19. Performance comparison of control schemes for variable-speed wind turbines

    Science.gov (United States)

    Bottasso, C. L.; Croce, A.; Savini, B.

    2007-07-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies.

  20. Performance comparison of control schemes for variable-speed wind turbines

    International Nuclear Information System (INIS)

    Bottasso, C L; Croce, A; Savini, B

    2007-01-01

    We analyze the performance of different control schemes when applied to the regulation problem of a variable-speed representative wind turbine. In particular, we formulate and compare a wind-scheduled PID, a LQR controller and a novel adaptive non-linear model predictive controller, equipped with observers of the tower states and wind. The simulations include gusts and turbulent winds of varying intensity in nominal as well as off-design operating conditions. The experiments highlight the possible advantages of model-based non-linear control strategies

  1. Evaluation and quality control of digital subtraction angiography systems

    International Nuclear Information System (INIS)

    Louisot, P.

    1986-04-01

    After reviewing the development of systems used in angiography, we rewind the medical interest and describe the steps of an angiographic examination. The following chapter is dedicated to the techniques used for the digitalization of video images. The components of the system involved in the image acquisition are thoroughly investigated in chapter 4. Then, we analyse the capabilities of the machines available in France in 1985. Chapter 6 is devoted to the criteria of quality in digital imaging. In order to assign qualitative values to the above criteria, we design a control procedure which is described in chapter 7. The procedure thus allows the estimate of the physical performances of angiographic digital subtraction systems [fr

  2. Photovoltaic System Equipped with Digital Command Control and Acquisition

    OpenAIRE

    Yaden, Med; Melhaoui, Mustapha; Gaamouche, Rajae; Hirech, Kamal; Baghaz, Elhadi; Kassmi, Khalil

    2013-01-01

    In this paper, we present results concerning the design, the realization and the characterization of a photovoltaic system (PV), equipped with a digital controls: Power Point Tracking (MPPT), charge/discharge lead acid batteries, sun tracker and supervision. These different functions are performed with a microcontroller that has capabilities and functions to the reliability of PV systems (signal generation Pulses Width Modulation (PWM), speed etc.). Concerning the MPPT control operation, we i...

  3. A reconfigurable strategy for distributed digital process control

    International Nuclear Information System (INIS)

    Garcia, H.E.; Ray, A.; Edwards, R.M.

    1990-01-01

    A reconfigurable control scheme is proposed which, unlike a preprogrammed one, uses stochastic automata to learn the current operating status of the environment (i.e., the plant, controller, and communication network) by dynamically monitoring the system performance and then switching to the appropriate controller on the basis of these observations. The potential applicability of this reconfigurable control scheme to electric power plants is being investigated. The plant under consideration is the Experimental Breeder Reactor (EBR-II) at the Argonne National Laboratory site in Idaho. The distributed control system is emulated on a ring network where the individual subsystems are hosted as follows: (1) the reconfigurable control modules are located in one of the network modules called Multifunction Controller; (2) the learning modules are resident in a VAX 11/785 mainframe computer; and (3) a detailed model of the plant under control is executed in the same mainframe. This configuration is a true representation of the network-based control system in the sense that it operates in real time and is capable of interacting with the actual plant

  4. A Highly Robust Single-Loop Current Control Scheme for Grid-Connected Inverter with an Improved LCCL Filter Configuration

    DEFF Research Database (Denmark)

    Pan, Donghua; Ruan, Xinbo; Wang, Xiongfei

    2018-01-01

    Single-loop current control is an attractive scheme for the LCL-type grid-connected inverter due to its simplicity and low cost. However, conventional single-loop control schemes, which command either the inverter current or the grid current, are subject to the specific resonance frequency region...

  5. Using a Novel Wireless-Networked Decentralized Control Scheme under Unpredictable Environmental Conditions.

    Science.gov (United States)

    Chang, Chung-Liang; Huang, Yi-Ming; Hong, Guo-Fong

    2015-11-12

    The direction of sunshine or the installation sites of environmental control facilities in the greenhouse result in different temperature and humidity levels in the various zones of the greenhouse, and thus, the production quality of crop is inconsistent. This study proposed a wireless-networked decentralized fuzzy control scheme to regulate the environmental parameters of various culture zones within a greenhouse. The proposed scheme can create different environmental conditions for cultivating different crops in various zones and achieve diversification or standardization of crop production. A star-type wireless sensor network is utilized to communicate with each sensing node, actuator node, and control node in various zones within the greenhouse. The fuzzy rule-based inference system is used to regulate the environmental parameters for temperature and humidity based on real-time data of plant growth response provided by a growth stage selector. The growth stage selector defines the control ranges of temperature and humidity of the various culture zones according to the leaf area of the plant, the number of leaves, and the cumulative amount of light. The experimental results show that the proposed scheme is stable and robust and provides basis for future greenhouse applications.

  6. Using a Novel Wireless-Networked Decentralized Control Scheme under Unpredictable Environmental Conditions

    Directory of Open Access Journals (Sweden)

    Chung-Liang Chang

    2015-11-01

    Full Text Available The direction of sunshine or the installation sites of environmental control facilities in the greenhouse result in different temperature and humidity levels in the various zones of the greenhouse, and thus, the production quality of crop is inconsistent. This study proposed a wireless-networked decentralized fuzzy control scheme to regulate the environmental parameters of various culture zones within a greenhouse. The proposed scheme can create different environmental conditions for cultivating different crops in various zones and achieve diversification or standardization of crop production. A star-type wireless sensor network is utilized to communicate with each sensing node, actuator node, and control node in various zones within the greenhouse. The fuzzy rule-based inference system is used to regulate the environmental parameters for temperature and humidity based on real-time data of plant growth response provided by a growth stage selector. The growth stage selector defines the control ranges of temperature and humidity of the various culture zones according to the leaf area of the plant, the number of leaves, and the cumulative amount of light. The experimental results show that the proposed scheme is stable and robust and provides basis for future greenhouse applications.

  7. Reliability Estimation for Digital Instrument/Control System

    International Nuclear Information System (INIS)

    Yang, Yaguang; Sydnor, Russell

    2011-01-01

    Digital instrumentation and controls (DI and C) systems are widely adopted in various industries because of their flexibility and ability to implement various functions that can be used to automatically monitor, analyze, and control complicated systems. It is anticipated that the DI and C will replace the traditional analog instrumentation and controls (AI and C) systems in all future nuclear reactor designs. There is an increasing interest for reliability and risk analyses for safety critical DI and C systems in regulatory organizations, such as The United States Nuclear Regulatory Commission. Developing reliability models and reliability estimation methods for digital reactor control and protection systems will involve every part of the DI and C system, such as sensors, signal conditioning and processing components, transmission lines and digital communication systems, D/A and A/D converters, computer system, signal processing software, control and protection software, power supply system, and actuators. Some of these components are hardware, such as sensors and actuators, their failure mechanisms are well understood, and the traditional reliability model and estimation methods can be directly applied. But many of these components are firmware which has software embedded in the hardware, and software needs special consideration because its failure mechanism is unique, and the reliability estimation method for a software system will be different from the ones used for hardware systems. In this paper, we will propose a reliability estimation method for the entire DI and C system reliability using a recently developed software reliability estimation method and a traditional hardware reliability estimation method

  8. Quality control of drugs. Certification scheme on the quality of pharmaceutical products moving in international commerce.

    Science.gov (United States)

    1979-01-01

    In an effort to ensure a desirable level of quality control of drugs in international commerce, the 28th World Health Assembly recommended, in its resolution WHA28.65, that Member States apply the requirements for "Good Practices in the Manufacture and Quality Control of Drugs" and participate in the Certification Scheme on the Quality of Pharmaceutical Products moving in International Commerce. Since the publication of the 1st list 13 countries (Austria, Congo, Denmark, El Salvador, India, Iran, Israel, Liberia, Swaziland, Thailand, Tunisia, United Republic of Tanzania, and Zaire) have informed the World Health Organization of their agreement to participate in the Certification Scheme, and the texts of their replies are included here.

  9. A Secure and Verifiable Outsourced Access Control Scheme in Fog-Cloud Computing.

    Science.gov (United States)

    Fan, Kai; Wang, Junxiong; Wang, Xin; Li, Hui; Yang, Yintang

    2017-07-24

    With the rapid development of big data and Internet of things (IOT), the number of networking devices and data volume are increasing dramatically. Fog computing, which extends cloud computing to the edge of the network can effectively solve the bottleneck problems of data transmission and data storage. However, security and privacy challenges are also arising in the fog-cloud computing environment. Ciphertext-policy attribute-based encryption (CP-ABE) can be adopted to realize data access control in fog-cloud computing systems. In this paper, we propose a verifiable outsourced multi-authority access control scheme, named VO-MAACS. In our construction, most encryption and decryption computations are outsourced to fog devices and the computation results can be verified by using our verification method. Meanwhile, to address the revocation issue, we design an efficient user and attribute revocation method for it. Finally, analysis and simulation results show that our scheme is both secure and highly efficient.

  10. Decentralized & Adaptive Load-Frequency Control Scheme of Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Hoseinzadeh, Bakhtyar; Silva, Filipe Miguel Faria da; Bak, Claus Leth

    2014-01-01

    In power systems with high penetration of Wind Power (WP), transferring a part of Load Frequency Control (LFC) burden to variable speed Wind Turbines (WTs) is inevitable. The conventional LFC schemes merely rely on frequency information and since frequency is a common variable throughout the netw......In power systems with high penetration of Wind Power (WP), transferring a part of Load Frequency Control (LFC) burden to variable speed Wind Turbines (WTs) is inevitable. The conventional LFC schemes merely rely on frequency information and since frequency is a common variable throughout...... and therefore determining the contribution factor of each individual WT to gain an adaptive LFC approach. The Electrical Distance (ED) concept confirms that the locally measured voltage decay is a proper criterion of closeness to the disturbance place. Numerical simulations carried out in DigSilent Power...

  11. Tegotae-based decentralised control scheme for autonomous gait transition of snake-like robots.

    Science.gov (United States)

    Kano, Takeshi; Yoshizawa, Ryo; Ishiguro, Akio

    2017-08-04

    Snakes change their locomotion patterns in response to the environment. This ability is a motivation for developing snake-like robots with highly adaptive functionality. In this study, a decentralised control scheme of snake-like robots that exhibited autonomous gait transition (i.e. the transition between concertina locomotion in narrow aisles and scaffold-based locomotion on unstructured terrains) was developed. Additionally, the control scheme was validated via simulations. A key insight revealed is that these locomotion patterns were not preprogrammed but emerged by exploiting Tegotae, a concept that describes the extent to which a perceived reaction matches a generated action. Unlike local reflexive mechanisms proposed previously, the Tegotae-based feedback mechanism enabled the robot to 'selectively' exploit environments beneficial for propulsion, and generated reasonable locomotion patterns. It is expected that the results of this study can form the basis to design robots that can work under unpredictable and unstructured environments.

  12. Quality control in digital mammography: the noise components

    Energy Technology Data Exchange (ETDEWEB)

    Leyton, Fernando [Universidade de Tarapaca, Arica (Chile). Centro de Estudios en Ciencias Radiologicas; Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nogueira, Maria do Socorro, E-mail: mnogue@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Duran, Maria Paz [Clinica Alemana, Santiago (Chile). Dept. de Radiologia; Dantas, Marcelino, E-mail: marcelino@inb.gov.b [Industrias Nucleares do Brasil (INB), Caldas, MG (Brazil). Unidade de Tratamento de Minerios; Ubeda, Carlos, E-mail: cubeda@uta.c [Universidade de Tarapaca, Arica (Chile). Fac. de Ciencias de la Salud

    2011-07-01

    To measure the linearity of the detector and determine the noise components (quantum, electronic and structural noise) that contributed to losing image quality and to determine the signal noise ratio (SNR) and contrast noise ratio (CNR). This paper describes the results of the implementation of a protocol for quality control in digital mammography performed in two direct digital mammography equipment (Hologic, Selenia) in Santiago of Chile. Shows the results of linearity and noise analysis of the images which establishes the main cause of noise in the image of the mammogram to ensure the quality and optimize procedures. The study evaluated two digital mammography's Selenia, Hologic (DR) from Santiago, Chile. We conducted the assessment of linearity of the detector, the signal noise ratio, contrast noise ratio and was determined the contribution of different noise components (quantum, electronics and structural noise). Used different thicknesses used in clinical practice according to the protocol for quality control in digital mammography of Spanish society of medical physics and NHSBSP Equipment Report 0604 Version 3. The Selenia mammography software was used for the analysis of images and Unfors Xi detector for measuring doses. The mammography detector has a linear performance, the CNR and SNR did not comply with the Protocol for the thicknesses of 60 and 70 mm. The main contribution of the noise corresponds to the quantum noise, therefore it is necessary to adjust and optimize the mammography system. (author)

  13. Quality control in digital mammography: the noise components

    International Nuclear Information System (INIS)

    Leyton, Fernando; Nogueira, Maria do Socorro; Duran, Maria Paz; Dantas, Marcelino; Ubeda, Carlos

    2011-01-01

    To measure the linearity of the detector and determine the noise components (quantum, electronic and structural noise) that contributed to losing image quality and to determine the signal noise ratio (SNR) and contrast noise ratio (CNR). This paper describes the results of the implementation of a protocol for quality control in digital mammography performed in two direct digital mammography equipment (Hologic, Selenia) in Santiago of Chile. Shows the results of linearity and noise analysis of the images which establishes the main cause of noise in the image of the mammogram to ensure the quality and optimize procedures. The study evaluated two digital mammography's Selenia, Hologic (DR) from Santiago, Chile. We conducted the assessment of linearity of the detector, the signal noise ratio, contrast noise ratio and was determined the contribution of different noise components (quantum, electronics and structural noise). Used different thicknesses used in clinical practice according to the protocol for quality control in digital mammography of Spanish society of medical physics and NHSBSP Equipment Report 0604 Version 3. The Selenia mammography software was used for the analysis of images and Unfors Xi detector for measuring doses. The mammography detector has a linear performance, the CNR and SNR did not comply with the Protocol for the thicknesses of 60 and 70 mm. The main contribution of the noise corresponds to the quantum noise, therefore it is necessary to adjust and optimize the mammography system. (author)

  14. A Fairness-Based Access Control Scheme to Optimize IPTV Fast Channel Changing

    Directory of Open Access Journals (Sweden)

    Junyu Lai

    2014-01-01

    Full Text Available IPTV services are typically featured with a longer channel changing delay compared to the conventional TV systems. The major contributor to this lies in the time spent on intraframe (I-frame acquisition during channel changing. Currently, most widely adopted fast channel changing (FCC methods rely on promptly transmitting to the client (conducting the channel changing a retained I-frame of the targeted channel as a separate unicasting stream. However, this I-frame acceleration mechanism has an inherent scalability problem due to the explosions of channel changing requests during commercial breaks. In this paper, we propose a fairness-based admission control (FAC scheme for the original I-frame acceleration mechanism to enhance its scalability by decreasing the bandwidth demands. Based on the channel changing history of every client, the FAC scheme can intelligently decide whether or not to conduct the I-frame acceleration for each channel change request. Comprehensive simulation experiments demonstrate the potential of our proposed FAC scheme to effectively optimize the scalability of the I-frame acceleration mechanism, particularly in commercial breaks. Meanwhile, the FAC scheme only slightly increases the average channel changing delay by temporarily disabling FCC (i.e., I-frame acceleration for the clients who are addicted to frequent channel zapping.

  15. Dynamic Contention Window Control Scheme in IEEE 802.11e EDCA-Based Wireless LANs

    Science.gov (United States)

    Abeysekera, B. A. Hirantha Sithira; Matsuda, Takahiro; Takine, Tetsuya

    In the IEEE 802.11 MAC protocol, access points (APs) are given the same priority as wireless terminals in terms of acquiring the wireless link, even though they aggregate several downlink flows. This feature leads to a serious throughput degradation of downlink flows, compared with uplink flows. In this paper, we propose a dynamic contention window control scheme for the IEEE 802.11e EDCA-based wireless LANs, in order to achieve fairness between uplink and downlink TCP flows while guaranteeing QoS requirements for real-time traffic. The proposed scheme first determines the minimum contention window size in the best-effort access category at APs, based on the number of TCP flows. It then determines the minimum and maximum contention window sizes in higher priority access categories, such as voice and video, so as to guarantee QoS requirements for these real-time traffic. Note that the proposed scheme does not require any modification to the MAC protocol at wireless terminals. Through simulation experiments, we show the effectiveness of the proposed scheme.

  16. Experimental bifurcation analysis of an impact oscillator - Tuning a non-invasive control scheme

    DEFF Research Database (Denmark)

    Bureau, Emil; Schilder, Frank; Santos, Ilmar

    2013-01-01

    We investigate a non-invasive, locally stabilizing control scheme necessary for an experimental bifurcation analysis. Our test-rig comprises a harmonically forced impact oscillator with hardening spring nonlinearity controlled by electromagnetic actuators, and serves as a prototype...... for electromagnetic bearings and other machinery with build-in actuators. We propose a sequence of experiments that allows one to choose optimal control-gains, filter parameters and settings for a continuation method without a priori study of a model. Depending on the algorithm for estimating the Jacobian required...

  17. Digital Control Techniques Based on Voltage Source Inverters in Renewable Energy Applications: A Review

    Directory of Open Access Journals (Sweden)

    Sohaib Tahir

    2018-02-01

    Full Text Available In the modern era, distributed generation is considered as an alternative source for power generation. Especially, need of the time is to provide the three-phase loads with smooth sinusoidal voltages having fixed frequency and amplitude. A common solution is the integration of power electronics converters in the systems for connecting distributed generation systems to the stand-alone loads. Thus, the presence of suitable control techniques, in the power electronic converters, for robust stability, abrupt response, optimal tracking ability and error eradication are inevitable. A comprehensive review based on design, analysis, validation of the most suitable digital control techniques and the options available for the researchers for improving the power quality is presented in this paper with their pros and cons. Comparisons based on the cost, schemes, performance, modulation techniques and coordinates system are also presented. Finally, the paper describes the performance evaluation of the control schemes on a voltage source inverter (VSI and proposes the different aspects to be considered for selecting a power electronics inverter topology, reference frames, filters, as well as control strategy.

  18. Control scheme for power modulation of a free piston Stirling engine

    Science.gov (United States)

    Dhar, Manmohan

    1989-01-01

    The present invention relates to a control scheme for power modulation of a free-piston Stirling engine-linear alternator power generator system. The present invention includes connecting an autotransformer in series with a tuning capacitance between a linear alternator and a utility grid to maintain a constant displacement to piston stroke ratio and their relative phase angle over a wide range of operating conditions.

  19. Segmentation Scheme for Safety Enhancement of Engineered Safety Features Component Control System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sangseok; Sohn, Kwangyoung [Korea Reliability Technology and System, Daejeon (Korea, Republic of); Lee, Junku; Park, Geunok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-05-15

    Common Caused Failure (CCF) or undetectable failure would adversely impact safety functions of ESF-CCS in the existing nuclear power plants. We propose the segmentation scheme to solve these problems. Main function assignment to segments in the proposed segmentation scheme is based on functional dependency and critical function success path by using the dependency depth matrix. The segment has functional independence and physical isolation. The segmentation structure is that prohibit failure propagation to others from undetectable failures. Therefore, the segmentation system structure has robustness to undetectable failures. The segmentation system structure has functional diversity. The specific function in the segment defected by CCF, the specific function could be maintained by diverse control function that assigned to other segments. Device level control signals and system level control signals are separated and also control signal and status signals are separated due to signal transmission paths are allocated independently based on signal type. In this kind of design, single device failure or failures on signal path in the channel couldn't result in the loss of all segmented functions simultaneously. Thus the proposed segmentation function is the design scheme that improves availability of safety functions. In conventional ESF-CCS, the single controller generates the signal to control the multiple safety functions, and the reliability is achieved by multiplication within the channel. This design has a drawback causing the loss of multiple functions due to the CCF (Common Cause Failure) and single failure Heterogeneous controller guarantees the diversity ensuring the execution of safety functions against the CCF and single failure, but requiring a lot of resources like manpower and cost. The segmentation technology based on the compartmentalization and functional diversification decreases the CCF and single failure nonetheless the identical types of

  20. Homography-based control scheme for mobile robots with nonholonomic and field-of-view constraints.

    Science.gov (United States)

    López-Nicolás, Gonzalo; Gans, Nicholas R; Bhattacharya, Sourabh; Sagüés, Carlos; Guerrero, Josechu J; Hutchinson, Seth

    2010-08-01

    In this paper, we present a visual servo controller that effects optimal paths for a nonholonomic differential drive robot with field-of-view constraints imposed by the vision system. The control scheme relies on the computation of homographies between current and goal images, but unlike previous homography-based methods, it does not use the homography to compute estimates of pose parameters. Instead, the control laws are directly expressed in terms of individual entries in the homography matrix. In particular, we develop individual control laws for the three path classes that define the language of optimal paths: rotations, straight-line segments, and logarithmic spirals. These control laws, as well as the switching conditions that define how to sequence path segments, are defined in terms of the entries of homography matrices. The selection of the corresponding control law requires the homography decomposition before starting the navigation. We provide a controllability and stability analysis for our system and give experimental results.

  1. Centralized digital computer control of a research nuclear reactor

    International Nuclear Information System (INIS)

    Crawford, K.C.

    1987-01-01

    A hardware and software design for the centralized control of a research nuclear reactor by a digital computer are presented, as well as an investigation of automatic-feedback control. Current reactor-control philosophies including redundancy, inherent safety in failure, and conservative-yet-operational scram initiation were used as the bases of the design. The control philosophies were applied to the power-monitoring system, the fuel-temperature monitoring system, the area-radiation monitoring system, and the overall system interaction. Unlike the single-function analog computers currently used to control research and commercial reactors, this system will be driven by a multifunction digital computer. Specifically, the system will perform control-rod movements to conform with operator requests, automatically log the required physical parameters during reactor operation, perform the required system tests, and monitor facility safety and security. Reactor power control is based on signals received from ion chambers located near the reactor core. Absorber-rod movements are made to control the rate of power increase or decrease during power changes and to control the power level during steady-state operation. Additionally, the system incorporates a rudimentary level of artificial intelligence

  2. A Low-Power Digitally Controlled Oscillator for All Digital Phase-Locked Loops

    Directory of Open Access Journals (Sweden)

    Jun Zhao

    2010-01-01

    Full Text Available A low-power and low-jitter 12-bit CMOS digitally controlled oscillator (DCO design is presented. The Low-Power CMOS DCO is designed based on the ring oscillator implemented with Schmitt trigger inverters. The proposed DCO circuit uses control codes of thermometer type to reduce jitters. Performance of the DCO is verified through a novel All Digital Phase-Locked Loop (ADPLL designed with a unique lock-in process by employing a time-to-digital converter, where both the frequency of the reference clock and the delay between DCO_output and DCO_clock is measured. A carefully designed reset process reduces the phase acquisition process to two cycles. The ADPLL was implemented using the 32 nm Predictive Technology Model (PTM at 0.9 V supply voltage, and the simulation results show that the proposed ADPLL achieves 10 and 2 reference cycles of frequency and phase acquisitions, respectively, at 700 MHz with less than 67 ps peak-to-peak jitter. The DCO consumes 2.2 mW at 650 MHz with 0.9 V power supply.

  3. Digital control computer upgrade at the Cernavoda NPP simulator

    International Nuclear Information System (INIS)

    Ionescu, T.

    2006-01-01

    The Plant Process Computer equips some Nuclear Power Plants, like CANDU-600, with Centralized Control performed by an assembly of two computers known as Digital Control Computers (DCC) and working in parallel for safely driving of the plan at steady state and during normal maneuvers but also during abnormal transients when the plant is automatically steered to a safe state. The Centralized Control means both hardware and software with obligatory presence in the frame of the Full Scope Simulator and subject to changing its configuration with specific requirements during the plant and simulator life and covered by this subsection

  4. Retrofit of new digital control systems in existing power stations

    International Nuclear Information System (INIS)

    Smith, J.E.; Baird, C.F.

    1986-01-01

    With the notable exception of the Canadian CANDU nuclear power stations, little use has been made of digital control in North American nuclear stations. Recently, however, there has been renewed interest in such systems within the nuclear industry in response to demands for better ergonomics in control room design and the obsolescence of control equipment whose fundamental design has changed little in 20 yr. Early in 1985, Atomic Energy of Canada Limited was asked by New Brunswick Power to advise on the redesign of the control systems for two fossil-fired generating stations, Coleson Cove and Courtenay Bay Unit 4. Coleson Cove is to be converted from oil to coal firing with consequent extensive control system changes and Courtenay Bay Unit 4 required a low-cost solution to the problem of relocating its control room from the existing isolated location to the combined control center used by units 1, 2, and 3. In both cases, the recommended solution involves the retrofit of state-of-the-art digital control systems. Although the units involved are nonnuclear the experience is applicable

  5. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter....... The experimental results of measured loop-gain at different operating points are presented to validate the theoretical performance of the controller....

  6. Frequency to digital converter for IUAC Linac control system

    International Nuclear Information System (INIS)

    Jain, Mamta; Subramaiam, E.T.; Sahu, B.K.

    2015-01-01

    A frequency to digital converter CAMAC module has been designed and developed for LINAC control systems. This module is used to see the frequency difference of master clock and the resonator frequency digitally without using the oscilloscope. Later on this can be used for automatic tuning and locking of the cavities using piezoelectric actuator based tunner control. This module has eight independent channels to fulfill the need of all the eight cavities of the cryostat. A Schmitt trigger along with level converaccepts almost any form of pulse train, with 30 Vp-p. The time period is measured by counters clocked from a high resolution clock (10 MHz +/- 250 ps). The counter values are cross checked at both the input levels. Frequency is obtained from the computed time period by a special divisor core implemented inside the FPGA. The major task was the implementation of eight individual divisor cores and routing inside one Spartan 3s500E FPGA chip

  7. Digital Control of External Devices through the Parallel Port of a ...

    African Journals Online (AJOL)

    the controlling voltage of 5V) which drives an electrically isolated circuit with a relay. A model of the system was built and the test result was satisfactory. Keywords: device controller, digital switching, digital interfacing, visual basic, computer ...

  8. An Effective Method on Applying Feedback Error Learning Scheme to Functional Electrical Stimulation Controller

    Science.gov (United States)

    Watanabe, Takashi; Kurosawa, Kenji; Yoshizawa, Makoto

    A Feedback Error Learning (FEL) scheme was found to be applicable to joint angle control by Functional Electrical Stimulation (FES) in our previous study. However, the FEL-FES controller had a problem in learning of the inverse dynamics model (IDM) in some cases. In this paper, methods of applying the FEL to FES control were examined in controlling 1-DOF movement of the wrist joint stimulating 2 muscles through computer simulation under several control conditions with several subject models. The problems in applying FEL to FES controller were suggested to be in restricting stimulation intensity to positive values between the minimum and the maximum intensities and in the case of very small output values of the IDM. Learning of the IDM was greatly improved by considering the IDM output range with setting the minimum ANN output value in calculating ANN connection weight change.

  9. A powerful ethernet interface module for digital camera control

    Science.gov (United States)

    Amato, Stephen M.; Geary, John C.

    2012-09-01

    We have found a commercially-available ethernet interface module with sufficient on-board resources to largely handle all timing generation tasks required by digital imaging systems found in astronomy. In addition to providing a high-bandwidth ethernet interface to the controller, it can largely replace the need for special-purpose timing circuitry. Examples for use with both CCD and CMOS imagers are provided.

  10. An Overview of Demand Side Management Control Schemes for Buildings in Smart Grids

    DEFF Research Database (Denmark)

    Kosek, Anna Magdalena; Costanzo, Giuseppe Tommaso; Bindner, Henrik W.

    2013-01-01

    demand is needed. The research area of demand side management is still very much in flux and several options are being presented which can all be used to manage loads in order to achieve a flexible and more responsive demand. These different control schemes are developed with different organization...... of the power sector in mind and thus can differ significantly in their architecture, their integration into the various markets, their integration into distribution network operation and several other aspects. This paper proposes a classification of load control policies for demand side management in smart...

  11. Design of coordinated controller in nuclear power plant based on digital instrument and control technology

    International Nuclear Information System (INIS)

    Cheng Shouyu; Peng Minjun; Liu Xinkai; Zhao Qiang; Deng Xiangxin

    2014-01-01

    Nuclear power plant (NPP) is a multi-input and multi-output, no-linear and time-varying complex system. The conventional PID controller is usually used in NPP control system which is based on analog instrument. The system parameters are easy to overshoot and the response time is longer in the control mode of the conventional PID. In order to improve this condition, a new coordinated control strategy which is based on expert system and the original controllers in the digital instrument and control technology was presented. In order to verify and validate it, the proposed coordinated control technology was tested by the full-scope real-time simulation system. The results prove that using digital instrument and control technology to achieve coordinated controller is feasible, the coordinated controller can effectively improve the dynamic operating characteristics of the system, and the coordinated controller is superior to the conventional PID controller in control performance. (authors)

  12. 47 CFR 73.9001 - Redistribution control of digital television broadcasts.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Redistribution control of digital television... RADIO SERVICES RADIO BROADCAST SERVICES Digital Broadcast Television Redistribution Control § 73.9001 Redistribution control of digital television broadcasts. Licensees of TV broadcast stations may utilize the...

  13. Digital controller for feedwater and recirculation flow control of BWR plant

    International Nuclear Information System (INIS)

    Sato, Takao; Ito, Tetsuo; Omori, Takashi; Iida, Hiroshi; Yanai, Katsuya.

    1980-01-01

    In nuclear power plants, it is required to operate the plants on load-following basis as the proportion of nuclear power plants in whole power supply network has been increasing. For this purpose, the requirements of more reliable, more automated plants and of the flexibility of operation are becoming serious. To respond to such demands, digital controllers are inevitable because analog controllers are limited in their controllability. It is also required to devise more intelligent systems such as those enabling strengthened diagnostic functions or sophisticated predictive control. On such background, duplicated redundant digital control system has been developed, using two control microcomputers and uniting the conventional feed-water control system and recirculation flow control system. The report discribes on the design concept for this digital controller, the hardware and software of the control system and the confirmation of the performance by simulation. The verifying test for the control performance, the simulation test for recirculation pump abnormality, the test for predictive control and the test on the response characteristics of recirculation system were carried out. The digital controller attained the MTBF 10 times as much, and the down time ratio 1/5 as small as those of the analog control systems. (Wakatsuki, Y.)

  14. Research methods of simulate digital compensators and autonomous control systems

    Directory of Open Access Journals (Sweden)

    V. S. Kudryashov

    2016-01-01

    Full Text Available The peculiarity of the present stage of development of the production is the need to control and regulate a large number of process parameters, the mutual influence on each other that when using single-circuit systems significantly reduces the quality of the transition process, resulting in significant costs of raw materials and energy, reduce the quality of the products. Using a stand-alone digital control system eliminates the correlation of technological parameters, to give the system the desired dynamic and static properties, improve the quality of regulation. However, the complexity of the configuration and implementation of procedures (modeling compensators autonomous systems of this type, associated with the need to perform a significant amount of complex analytic transformation significantly limit the scope of their application. In this regard, the approach based on the decompo sition proposed methods of calculation and simulation (realization, consisting in submitting elements autonomous control part digital control system in a series parallel connection. The above theoretical study carried out in a general way for any dimension systems. The results of computational experiments, obtained during the simulation of the four autonomous control systems, comparative analysis and conclusions on the effectiveness of the use of each of the methods. The results obtained can be used in the development of multi-dimensional process control systems.

  15. Digitally Controlled Converter with Dynamic Change of Control Law and Power Throughput

    DEFF Research Database (Denmark)

    Nesgaard, Carsten; Andersen, Michael Andreas E.; Nielsen, Nils

    2003-01-01

    the substitution of analog controllers with their digital counterparts are considered. The outline of the paper is divided into two segments – the first being an experimental analysis of the timing behavior by means of code optimization – the second being an examination of the dynamics of incorporating two control......With the continuous development of faster and cheaper microprocessors the field of applications for digital control is constantly expanding. Based on this trend the paper at hand describes the analysis and implementation of multiple control laws within the same controller. Also, implemented within...

  16. 60 GHz 5-bit digital controlled phase shifter in a digital 40 nm CMOS technology without ultra-thick metals

    NARCIS (Netherlands)

    Gao, H.; Ying, K.; Matters-Kammerer, M.K.; Harpe, P.; Wang, B.; Liu, B.; Serdijn, W.A.; Baltus, P.G.M.

    2016-01-01

    A 5-bit digital controlled switch-type passive phase shifter realised in a 40 nm digital CMOS technology without ultra-thick metals for the 60 GHz Industrial, Scientific and Medical (ISM) band is presented. A patterned shielding with electromagnetic bandgap structure and a stacked metals method to

  17. Influence of discretization method on the digital control system performance

    Directory of Open Access Journals (Sweden)

    Futás József

    2003-12-01

    Full Text Available The design of control system can be divided into two steps. First the process or plant have to be convert into mathematical model form, so that its behavior can be analyzed. Then an appropriate controller have to be design in order to get the desired response of the controlled system. In the continuous time domain the system is represented by differential equations. Replacing a continuous system into discrete time form is always an approximation of the continuous system. The different discretization methods give different digital controller performance. The methods presented on the paper are Step Invariant or Zero Order Hold (ZOH Method, Matched Pole-Zero Method, Backward difference Method and Bilinear transformation. The above mentioned discretization methods are used in developing PI position controller of a dc motor. The motor model was converted by the ZOH method. The performances of the different methods are compared and the results are presented.

  18. High-Resolution Synthesizable Digitally-Controlled Delay Lines

    Science.gov (United States)

    Giordano, R.; Ameli, F.; Bifulco, P.; Bocci, V.; Cadeddu, S.; Izzo, V.; Lai, A.; Mastroianni, S.; Aloisio, A.

    2015-12-01

    Digitally-controlled delay lines (DCDLs) play a key role in timing distribution for trigger and data acquisition systems (TDAQ) of high energy Physics (HEP), where it is often necessary to add an open-loop fine-grained programmable phase delay to distributed clocks and/or data lines. In this work, we present the performance of DCDLs implemented according to an all-digital novel architecture. The architecture is completely technology-independent, it is described by means of a hardware description language and it can be placed and routed with automatic tools. Our solution is aimed at being used as a synthesizable block in FPGAs, as a proof-of-concept we implemented a prototype in a Xilinx Kintex-7 FPGA. We discuss the measured performance of the implemented delay line in terms of delay range, resolution and linearity. The logic utilization of the delay lines is also presented in the view of a scalable implementation.

  19. Speed Digital Control of Brushless DC Motor Using dsPIC Controller

    Directory of Open Access Journals (Sweden)

    Gheorghe Băluţă

    2014-09-01

    Full Text Available This paper presents the digital control of the Brushless DC motor (BLDCM speed. The dsPICDEM MC1 development system (with the dsPIC30F6010A microcontroller and the dsPICDEM MC1L power module, manufactured by Microchip Company, were used. The control program was developed in C programming language. The graphical user interface was realized in LabVIEW 8.6 graphical programming language. For speed control, a digital controller PI type was implemented. Due to digital controller well chosen and well tuned, the system response at speed step variation is very good. Therewith, the experimental results obtained also show a good compensation of disturbance which does not happen in open-loop control.

  20. High Efficient CMOS Class-E Power Amplifier with a New Output Power Control Scheme

    Directory of Open Access Journals (Sweden)

    MESHKIN Reza

    2013-05-01

    Full Text Available This paper presents the design of a novel RF power amplifier (PA with a new output power control scheme suitable for RF-ICs and portable systems. Employing a class-E amplifier as a drivertogether with soft-switching property of the main power stage switching mode class-E PA helps to achieve better efficiency and increases the capability of circuit integration. A new circuit scheme for efficient output power control is introduced in the proposed PAbased on the array of switches and compensated shunt capacitors with different sizes. This technique improves the Power-Added-Efficiency (PAE and its drop specially at lower output power levels in comparison with conventional power control methods. The layoutof the designed PA is made in 0.18um 1P6M CMOS process, and the chip area is 1.7mm2. simulation results show that the designed PA delivers 21.09dBm output power to a 50 standard load from a 1.8V supply voltage at 2.4GHz operating frequency with 57% PAE. Additionally, the output power of the PA is controlled with steps of 1-dBm by using the proposed array of switches and capacitors.

  1. Rate control scheme for consistent video quality in scalable video codec.

    Science.gov (United States)

    Seo, Chan-Won; Han, Jong-Ki; Nguyen, Truong Q

    2011-08-01

    Multimedia data delivered to mobile devices over wireless channels or the Internet are complicated by bandwidth fluctuation and the variety of mobile devices. Scalable video coding has been developed as an extension of H.264/AVC to solve this problem. Since scalable video codec provides various scalabilities to adapt the bitstream for the channel conditions and terminal types, scalable codec is one of the useful codecs for wired or wireless multimedia communication systems, such as IPTV and streaming services. In such scalable multimedia communication systems, video quality fluctuation degrades the visual perception significantly. It is important to efficiently use the target bits in order to maintain a consistent video quality or achieve a small distortion variation throughout the whole video sequence. The scheme proposed in this paper provides a useful function to control video quality in applications supporting scalability, whereas conventional schemes have been proposed to control video quality in the H.264 and MPEG-4 systems. The proposed algorithm decides the quantization parameter of the enhancement layer to maintain a consistent video quality throughout the entire sequence. The video quality of the enhancement layer is controlled based on a closed-form formula which utilizes the residual data and quantization error of the base layer. The simulation results show that the proposed algorithm controls the frame quality of the enhancement layer in a simple operation, where the parameter decision algorithm is applied to each frame.

  2. A Fault-tolerable Control Scheme for an Open-frame Underwater Vehicle

    Directory of Open Access Journals (Sweden)

    Huang Hai

    2014-05-01

    Full Text Available Open-frame is one of the major types of structures of Remote Operated Vehicles (ROV because it is easy to place sensors and operations equipment onboard. Firstly, this paper designed a petri-based recurrent neural network (PRFNN to improve the robustness with response to nonlinear characteristics and strong disturbance of an open-frame underwater vehicle. A threshold has been set in the third layer to reduce the amount of calculations and regulate the training process. The whole network convergence is guaranteed with the selection of learning rate parameters. Secondly, a fault tolerance control (FTC scheme is established with the optimal allocation of thrust. Infinity-norm optimization has been combined with 2-norm optimization to construct a bi-criteria primal-dual neural network FTC scheme. In the experiments and simulation, PRFNN outperformed fuzzy neural networks in motion control, while bi-criteria optimization outperformed 2-norm optimization in FTC, which demonstrates that the FTC controller can improve computational efficiency, reduce control errors, and implement fault tolerable thrust allocation.

  3. A Digitally Controllable Polymer-Based Microfluidic Mixing Module Array

    Directory of Open Access Journals (Sweden)

    Raymond H. W. Lam

    2012-03-01

    Full Text Available This paper presents an integrated digitally controllable microfluidic system for continuous solution supply with a real-time concentration control. This system contains multiple independently operating mixing modules, each integrated with two vortex micropumps, two Tesla valves and a micromixer. The interior surface of the system is made of biocompatible materials using a polymer micro-fabrication process and thus its operation can be applied to chemicals and bio-reagents. In each module, pumping of fluid is achieved by the vortex micropump working with the rotation of a micro-impeller. The downstream fluid mixing is based on mechanical vibrations driven by a lead zirconate titanate ceramic diaphragm actuator located below the mixing chamber. We have conducted experiments to prove that the addition of the micro-pillar structures to the mixing chamber further improves the mixing performance. We also developed a computer-controlled automated driver system to control the real-time fluid mixing and concentration regulation with the mixing module array. This research demonstrates the integration of digitally controllable polymer-based microfluidic modules as a fully functional system, which has great potential in the automation of many bio-fluid handling processes in bio-related applications.

  4. Advanced control schemes and kinematic analysis for a kinematically redundant 7 DOF manipulator

    Science.gov (United States)

    Nguyen, Charles C.; Zhou, Zhen-Lei

    1990-01-01

    The kinematic analysis and control of a kinematically redundant manipulator is addressed. The manipulator is the slave arm of a telerobot system recently built at Goddard Space Flight Center (GSFC) to serve as a testbed for investigating research issues in telerobotics. A forward kinematic transformation is developed in its most simplified form, suitable for real-time control applications, and the manipulator Jacobian is derived using the vector cross product method. Using the developed forward kinematic transformation and quaternion representation of orientation matrices, we perform computer simulation to evaluate the efficiency of the Jacobian in converting joint velocities into Cartesian velocities and to investigate the accuracy of Jacobian pseudo-inverse for various sampling times. The equivalence between Cartesian velocities and quaternion is also verified using computer simulation. Three control schemes are proposed and discussed for controlling the motion of the slave arm end-effector.

  5. Improved FRT Control Scheme for DFIG Wind Turbine Connected to a Weak Grid

    DEFF Research Database (Denmark)

    Abulanwar, Elsayed; Chen, Zhe; Iov, Florin

    2013-01-01

    This paper presents an improved coordinated fault ridethrough (FRT) control strategy for a doubly fed induction generator (DFIG) based wind turbine, (WT), in a weak grid. A technique for grid synchronization against voltage excursions, i.e., a Dual Second Order Generalized Integrator – Frequency...... Locked Loop (DSOGIFLL) is utilized to extract a robust grid voltage synchronization signal irrespective of the mains condition to enhance the overall system performance. Besides, a decoupled double synchronous reference frame (DDSRF) dq current controller is devoted for the grid side converter, (GSC......), controller to counteract current ripples and tackle the DC link voltage fluctuations. Also, a reactive power support scheme to manage the DFIG reactive power during contingencies and fulfill the grid codes obligations is presented. Moreover, additional control terms are employed with the DFIG converters...

  6. A Polar Fuzzy Control Scheme for Hybrid Power System Using Vehicle-To-Grid Technique

    Directory of Open Access Journals (Sweden)

    Mohammed Elsayed Lotfy

    2017-07-01

    Full Text Available A novel polar fuzzy (PF control approach for a hybrid power system is proposed in this research. The proposed control scheme remedies the issues of system frequency and the continuity of demand supply caused by renewable sources’ uncertainties. The hybrid power system consists of a wind turbine generator (WTG, solar photovoltaics (PV, a solar thermal power generator (STPG, a diesel engine generator (DEG, an aqua-electrolyzer (AE, an ultra-capacitor (UC, a fuel-cell (FC, and a flywheel (FW. Furthermore, due to the high cost of the battery energy storage system (BESS, a new idea of vehicle-to-grid (V2G control is applied to use the battery of the electric vehicle (EV as equivalent to large-scale energy storage units instead of small batteries to improve the frequency stability of the system. In addition, EV customers’ convenience is taken into account. A minimal-order observer is used to estimate the supply error. Then, the area control error (ACE signal is calculated in terms of the estimated supply error and the frequency deviation. ACE is considered in the frequency domain. Two PF approaches are utilized in the intended system. The mission of each controller is to mitigate one frequency component of ACE. The responsibility for ACE compensation is shared among all parts of the system according to their speed of response. The performance of the proposed control scheme is compared to the conventional fuzzy logic control (FLC. The effectiveness and robustness of the proposed control technique are verified by numerical simulations under various scenarios.

  7. Stream nitrogen sources apportionment and pollution control scheme development in an agricultural watershed in eastern China.

    Science.gov (United States)

    Chen, Dingjiang; Lu, Jun; Huang, Hong; Liu, Mei; Gong, Dongqin; Chen, Jiabo

    2013-08-01

    A modeling system that couples a land-usebased export coefficient model, a stream nutrient transport equation, and Bayesian statistics was developed for stream nitrogen source apportionment. It divides a watershed into several sub-catchments, and then considers the major landuse categories as stream nitrogen sources in each subcatchment. The runoff depth and stream water depth are considered as the major factors influencing delivery of nitrogen from land to downstream stream node within each sub-catchment. The nitrogen sources and delivery processes are lumped into several constant parameters that were calibrated using Bayesian statistics from commonly available stream monitoring and land-use datasets. This modeling system was successfully applied to total nitrogen (TN) pollution control scheme development for the ChangLe River watershed containing six sub-catchments and four land-use categories. The temporal (across months and years) and spatial (across sub-catchments and land-use categories) variability of nonpoint source (NPS) TN export to stream channels and delivery to the watershed outlet were assessed. After adjustment for in-stream TNretention, the time periods and watershed areas with disproportionately high-TN contributions to the stream were identified. Aimed at a target stream TN level of 2 mg L-1, a quantitative TN pollution control scheme was further developed to determine which sub-catchments, which land-use categories in a sub-catchment, which time periods, and how large of NPS TN export reduction were required. This modeling system provides a powerful tool for stream nitrogen source apportionment and pollution control scheme development at the watershed scale and has only limited data requirements.

  8. Digital Signal Processing and Control for the Study of Gene Networks

    Science.gov (United States)

    Shin, Yong-Jun

    2016-04-01

    Thanks to the digital revolution, digital signal processing and control has been widely used in many areas of science and engineering today. It provides practical and powerful tools to model, simulate, analyze, design, measure, and control complex and dynamic systems such as robots and aircrafts. Gene networks are also complex dynamic systems which can be studied via digital signal processing and control. Unlike conventional computational methods, this approach is capable of not only modeling but also controlling gene networks since the experimental environment is mostly digital today. The overall aim of this article is to introduce digital signal processing and control as a useful tool for the study of gene networks.

  9. Digital Signal Processing and Control for the Study of Gene Networks.

    Science.gov (United States)

    Shin, Yong-Jun

    2016-04-22

    Thanks to the digital revolution, digital signal processing and control has been widely used in many areas of science and engineering today. It provides practical and powerful tools to model, simulate, analyze, design, measure, and control complex and dynamic systems such as robots and aircrafts. Gene networks are also complex dynamic systems which can be studied via digital signal processing and control. Unlike conventional computational methods, this approach is capable of not only modeling but also controlling gene networks since the experimental environment is mostly digital today. The overall aim of this article is to introduce digital signal processing and control as a useful tool for the study of gene networks.

  10. A Combined Two-Method MPPT Control Scheme for Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Dorofte, Christinel; Borup, Uffe; Blaabjerg, Frede

    2005-01-01

    In order to increase the output efficiency of a grid-connected photovoltaic (PV) system it is important to have an efficient Maximum Power Point Tracker (MPPT). In the case of low irradiation, the Perturb and Observe (PO) and Incremental Conductance (IC) methods have a poor efficiency, because...... of the poor resolution in the acquired signals, when a fixed point implementation is done. A cost-effective two-method MPPT control scheme is proposed in this paper to track the maximum power point (MPP) at both low and high irradiation, by combining a Constant Voltage (CV) method and modified PO algorithm...

  11. A Combined Two-Method MPPT Control Scheme for Grid-Connected Photovoltaic Systems

    DEFF Research Database (Denmark)

    Dorofte, Christinel; Borup, Uffe; Blaabjerg, Frede

    2005-01-01

    of the poor resolution in the acquired signals, when a fixed point implementation is done. A cost-effective two-method MPPT control scheme is proposed in this paper to track the maximum power point (MPP) at both low and high irradiation, by combining a Constant Voltage (CV) method and modified PO algorithm......In order to increase the output efficiency of a grid-connected photovoltaic (PV) system it is important to have an efficient Maximum Power Point Tracker (MPPT). In the case of low irradiation, the Perturb and Observe (PO) and Incremental Conductance (IC) methods have a poor efficiency, because...

  12. Optimal sampling period of the digital control system for the nuclear power plant steam generator water level control

    International Nuclear Information System (INIS)

    Hur, Woo Sung; Seong, Poong Hyun

    1995-01-01

    A great effort has been made to improve the nuclear plant control system by use of digital technologies and a long term schedule for the control system upgrade has been prepared with an aim to implementation in the next generation nuclear plants. In case of digital control system, it is important to decide the sampling period for analysis and design of the system, because the performance and the stability of a digital control system depend on the value of the sampling period of the digital control system. There is, however, currently no systematic method used universally for determining the sampling period of the digital control system. Generally, a traditional way to select the sampling frequency is to use 20 to 30 times the bandwidth of the analog control system which has the same system configuration and parameters as the digital one. In this paper, a new method to select the sampling period is suggested which takes into account of the performance as well as the stability of the digital control system. By use of the Irving's model steam generator, the optimal sampling period of an assumptive digital control system for steam generator level control is estimated and is actually verified in the digital control simulation system for Kori-2 nuclear power plant steam generator level control. Consequently, we conclude the optimal sampling period of the digital control system for Kori-2 nuclear power plant steam generator level control is 1 second for all power ranges. 7 figs., 3 tabs., 8 refs. (Author)

  13. Digitally controlled analog proportional-integral-derivative (PID) controller for high-speed scanning probe microscopy.

    Science.gov (United States)

    Dukic, Maja; Todorov, Vencislav; Andany, Santiago; Nievergelt, Adrian P; Yang, Chen; Hosseini, Nahid; Fantner, Georg E

    2017-12-01

    Nearly all scanning probe microscopes (SPMs) contain a feedback controller, which is used to move the scanner in the direction of the z-axis in order to maintain a constant setpoint based on the tip-sample interaction. The most frequently used feedback controller in SPMs is the proportional-integral (PI) controller. The bandwidth of the PI controller presents one of the speed limiting factors in high-speed SPMs, where higher bandwidths enable faster scanning speeds and higher imaging resolution. Most SPM systems use digital signal processor-based PI feedback controllers, which require analog-to-digital and digital-to-analog converters. These converters introduce additional feedback delays which limit the achievable imaging speed and resolution. In this paper, we present a digitally controlled analog proportional-integral-derivative (PID) controller. The controller implementation allows tunability of the PID gains over a large amplification and frequency range, while also providing precise control of the system and reproducibility of the gain parameters. By using the analog PID controller, we were able to perform successful atomic force microscopy imaging of a standard silicon calibration grating at line rates up to several kHz.

  14. Digitally controlled analog proportional-integral-derivative (PID) controller for high-speed scanning probe microscopy

    Science.gov (United States)

    Dukic, Maja; Todorov, Vencislav; Andany, Santiago; Nievergelt, Adrian P.; Yang, Chen; Hosseini, Nahid; Fantner, Georg E.

    2017-12-01

    Nearly all scanning probe microscopes (SPMs) contain a feedback controller, which is used to move the scanner in the direction of the z-axis in order to maintain a constant setpoint based on the tip-sample interaction. The most frequently used feedback controller in SPMs is the proportional-integral (PI) controller. The bandwidth of the PI controller presents one of the speed limiting factors in high-speed SPMs, where higher bandwidths enable faster scanning speeds and higher imaging resolution. Most SPM systems use digital signal processor-based PI feedback controllers, which require analog-to-digital and digital-to-analog converters. These converters introduce additional feedback delays which limit the achievable imaging speed and resolution. In this paper, we present a digitally controlled analog proportional-integral-derivative (PID) controller. The controller implementation allows tunability of the PID gains over a large amplification and frequency range, while also providing precise control of the system and reproducibility of the gain parameters. By using the analog PID controller, we were able to perform successful atomic force microscopy imaging of a standard silicon calibration grating at line rates up to several kHz.

  15. Migration of Older to New Digital Control Systems in Nuclear Power Plant Main Control Rooms

    Energy Technology Data Exchange (ETDEWEB)

    Kovesdi, Casey Robert [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey Clark [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-04-01

    The United States (U.S.) Department of Energy (DOE) Office of Nuclear Energy (NE) has the primary mission to advance nuclear power by resolving socio-technical issues through research and development (R&D). One DOE-NE activity supporting this mission is the Light Water Reactor Sustainability (LWRS) program. LWRS has the overall objective to sustain the operation of existing commercial nuclear power plants (NPPs) through conducting R&D across multiple “pathways,” or R&D focus areas. The Advanced Instrumentation, Information, and Control (II&C) Systems Technologies pathway conducts targeted R&D to address aging and reliability concerns with the legacy instrumentation and control (I&C) and related information systems in operating U.S. NPPs. This work involves (1) ensuring that legacy analog II&C systems are not life-limiting issues for the LWR fleet, and (2) implementing digital II&C technology in a manner that enables broad innovation and business improvement in the NPP operating model. Under the LWRS Advanced II&C pathway, Human Factors experts at Idaho National Laboratory (INL) have been conducting R&D in support of NPP main control room (MCR) modernization activities. Work in prior years has focused on migrating analog I&C systems to new digital I&C systems (). In fiscal year 2016 (FY16), one new focus area for this research is migrating older digital I&C systems to new and advanced digital I&C systems. This report summarizes a plan for conducting a digital-to-digital migration of a legacy digital I&C system to a new digital I&C system in support of control room modernization activities.

  16. A Modified Control Scheme of Droop-Based Converters for Power Stability Analysis in Microgrids

    Directory of Open Access Journals (Sweden)

    Igor Usunariz

    2015-01-01

    Full Text Available Microgrid is principally an active distribution network since it aggregates numerous DG systems through their interface converters and different loads at distribution level. This paper discusses the power sharing in autonomous AC-microgrid infrastructure by common P-f and Q-V˙ droop control schemes on parallel-connected converters. Moreover, this research work proposes a frequency and voltage restoration mechanism through the utilization of secondary control. Experimental results are presented for a two-50 kVA parallel-connected converter-based system, demonstrating the necessity for the proper operation of the secondary control in order to monitor the system’s capability to withstand any perturbations that may occur and to ensure the system’s security.

  17. Continuous quality control of the blood sampling procedure using a structured observation scheme

    DEFF Research Database (Denmark)

    Seemann, T. L.; Nybo, M.

    2015-01-01

    Background: An important preanalytical factor is the blood sampling procedure and its adherence to the guidelines, i.e. CLSI and ISO 15189, in order to ensure a consistent quality of the blood collection. Therefore, it is critically important to introduce quality control on this part of the process....... As suggested by the EFLM working group on the preanalytical phase we introduced continuous quality control of the blood sampling procedure using a structured observation scheme to monitor the quality of blood sampling performed on an everyday basis. Materials and methods: Based on our own routines the EFLM....... Conclusion: It is possible to establish a continuous quality control on blood sampling. It has been well accepted by the staff and we have already been able to identify critical areas in the sampling process. We find that continuous auditing increase focus on the quality of blood collection which ensures...

  18. Implementation considerations for digital control systems in power plants: Final report

    International Nuclear Information System (INIS)

    Shah, S.C.; Lehman, L.L.; Sarchet, M.M.

    1988-09-01

    Conversion of nuclear power plants fron analog to digital control systems will require careful design, testing, and integration of the control algorithms, the software which implements the algorithms, the digital instrumentation, the digital communications network, and analog/digital device interfaces. Digital control systems are more flexible than their analog counterparts, and therefore greater attention must be paid by the customer to all stages of the control system design process. This flexibility also provides the framework for development of significant safety and reliability are inherant aspects of the chosen design processes. Digital control algorithms are capable of improving their performance by on-line self-tuning of the control parameters. It is therefore incumbant on system designers to choose self-tuning algorithms for power plant control. Implementation of these algorithms in software required a careful software design and development process to minimize errors in interpretation of the engineering design and prevent the inclusion of programming errors during software production. Digital control system and communications software must exhibit sufficient ''fault tolerance'' to maintain some level of safe plant operation or execute a safe plant shutdown in the event of both hard equipment failures and the appearance of software design faults. A number of standardized digital communications protocols are available to designers of digital control systems. These standardized digital communications protocols provide reliable fault tolerant communication between all digital elements of the plant control system and can be implemented redundantly to further enhance power plant operational safety. 5 refs., 11 figs., 1 tab

  19. A Novel Adaptive Observer-Based Control Scheme for Synchronization and Suppression of a Class of Uncertain Chaotic Systems

    International Nuclear Information System (INIS)

    Jing, Wang; Zhen-Yu, Tan; Xi-Kui, Ma; Jin-Feng, Gao

    2009-01-01

    A novel adaptive observer-based control scheme is presented for synchronization and suppression of a class of uncertain chaotic system. First, an adaptive observer based on an orthogonal neural network is designed. Subsequently, the sliding mode controllers via the proposed adaptive observer are proposed for synchronization and suppression of the uncertain chaotic systems. Theoretical analysis and numerical simulation show the effectiveness of the proposed scheme. (general)

  20. Polynomial Digital Control of a Series Equal Liquid Tanks

    Directory of Open Access Journals (Sweden)

    Bobála Vladimír

    2016-01-01

    Full Text Available Time-delays are mainly caused by the time required to transport mass, energy or information, but they can also be caused by processing time or accumulation. Typical examples of such processes are e.g. pumps, liquid storing tanks, distillation columns or some types of chemical reactors. In many cases time-delay is caused by the effect produced by the accumulation of a large number of low-order systems. Several industrial processes have the time-delay effect produced by the accumulation of a great number of low-order systems with the identical dynamic. The dynamic behavior of series these low-order systems is expressed by high-order system. One of possibilities of control of such processes is their approximation by low-order model with time-delay. The paper is focused on the design of the digital polynomial control of a set of equal liquid cylinder atmospheric tanks. The designed control algorithms are realized using the digital Smith Predictor (SP based on polynomial approach – by minimization of the Linear Quadratic (LQ criterion. The LQ criterion was combined with pole assignment.

  1. Adaptive Numerical Dissipation Control in High Order Schemes for Multi-D Non-Ideal MHD

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, B.

    2005-01-01

    The required type and amount of numerical dissipation/filter to accurately resolve all relevant multiscales of complex MHD unsteady high-speed shock/shear/turbulence/combustion problems are not only physical problem dependent, but also vary from one flow region to another. In addition, proper and efficient control of the divergence of the magnetic field (Div(B)) numerical error for high order shock-capturing methods poses extra requirements for the considered type of CPU intensive computations. The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multiresolution wavelets (WAV) (for the above types of flow feature). These filters also provide a natural and efficient way for the minimization of Div(B) numerical error.

  2. Coordinated single-phase control scheme for voltage unbalance reduction in low voltage network.

    Science.gov (United States)

    Pullaguram, Deepak; Mishra, Sukumar; Senroy, Nilanjan

    2017-08-13

    Low voltage (LV) distribution systems are typically unbalanced in nature due to unbalanced loading and unsymmetrical line configuration. This situation is further aggravated by single-phase power injections. A coordinated control scheme is proposed for single-phase sources, to reduce voltage unbalance. A consensus-based coordination is achieved using a multi-agent system, where each agent estimates the averaged global voltage and current magnitudes of individual phases in the LV network. These estimated values are used to modify the reference power of individual single-phase sources, to ensure system-wide balanced voltages and proper power sharing among sources connected to the same phase. Further, the high X / R ratio of the filter, used in the inverter of the single-phase source, enables control of reactive power, to minimize voltage unbalance locally. The proposed scheme is validated by simulating a LV distribution network with multiple single-phase sources subjected to various perturbations.This article is part of the themed issue 'Energy management: flexibility, risk and optimization'. © 2017 The Author(s).

  3. A new control scheme for PID load frequency controller of single-area and multi-area power systems.

    Science.gov (United States)

    Padhan, Dola Gobinda; Majhi, Somanath

    2013-03-01

    A new control structure with a tuning method to design a PID load frequency controller for power systems is presented. Initially, the controller is designed for single area power system, then it is extended to multi-area case. The controller parameters are obtained by expanding controller transfer function using Laurent series. Relay based identification technique is adopted to estimate power system dynamics. Robustness studies on stability and performance are provided, with respect to uncertainties in the plant parameters. The proposed scheme ensures that overall system remains asymptotically stable for all bounded uncertainties and for system oscillations. Simulation results show the feasibility of the approach and the proposed method improves the load disturbance rejection performance significantly even in the presence of the uncertainties in plant parameters. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Design optimization for main control room temperature and humidity control of digital nuclear power plant

    International Nuclear Information System (INIS)

    Chen Yujuan; Mao Hongwei; Liu Dongbo; Chen Donglei

    2014-01-01

    The main control room (MCR) temperature and humidity control system of nuclear power plant has major capacity lag and some interference factors. In order to meet the human factor requirements of MCR's operators and the control panels' environmental requirements, the improved temperature and humidity control scheme was designed based on the provided temperature cascade control system and the humidity cascade control system. In order to overcome the PID controller's shortcoming heavily depending on the accurate mathematical model, an intelligent PID parameter setting method was provided with the improved particle swarm optimization (PSO) algorithm. (authors)

  5. Thrusting maneuver control of a small spacecraft via only gimbaled-thruster scheme

    Science.gov (United States)

    Kabganian, Mansour; Kouhi, Hamed; Shahravi, Morteza; Fani Saberi, Farhad

    2018-05-01

    The thrust vector control (TVC) scheme is a powerful method in spacecraft attitude control. Since the control of a small spacecraft is being studied here, a solid rocket motor (SRM) should be used instead of a liquid propellant motor. Among the TVC methods, gimbaled-TVC as an efficient method is employed in this paper. The spacecraft structure is composed of a body and a gimbaled-SRM where common attitude control systems such as reaction control system (RCS) and spin-stabilization are not presented. A nonlinear two-body model is considered for the characterization of the gimbaled-thruster spacecraft where, the only control input is provided by a gimbal actuator. The attitude of the spacecraft is affected by a large exogenous disturbance torque which is generated by a thrust vector misalignment from the center of mass (C.M). A linear control law is designed to stabilize the spacecraft attitude while rejecting the mentioned disturbance torque. A semi-analytical formulation of the region of attraction (RoA) is developed to ensure the local stability and fast convergence of the nonlinear closed-loop system. Simulation results of the 3D maneuvers are included to show the applicability of this method for use in a small spacecraft.

  6. 23 µW 8.9-effective number of bit 1.1 MS/s successive approximation register analog-to-digital converter with an energy-efficient digital-to-analog converter switching scheme

    Directory of Open Access Journals (Sweden)

    Lei Sun

    2014-08-01

    Full Text Available This study presents a successive approximation register analog-to-digital converter with an energy-efficient switching scheme. A split-most significant bit capacitor array is used with a least significant bit-down switching scheme. Compared with the conventional binary-weighted capacitor array, it reduces the area and average switching energy by 50 and 87% under the same unit capacitor. Moreover, capacitor matching requirement is relaxed by 75%. A prototype design was fabricated in a 0.13 µm complementary metal oxide semiconductor process. It consumes 23.2 µW under 1 V analog supply and 0.5 V digital supply. Measured results show a peak signal-to-distortion-and-noise ratio of 55.2 dB and an effective resolution bandwidth up to 1.1 MHz when it operates at 1.1 MS/s. Its figure-of-merit is 44.1 fJ/conversion-step.

  7. Structure of a scheme of emergency control to avoid blackout due to interconnection lines loss

    Energy Technology Data Exchange (ETDEWEB)

    Luz, L.T. da; Werberich, L.C.; Herve, H.M. [Companhia Estadual de Energia Eletrica do Estado do Rio Grande do Sul (CEEE), Porto Alegre, RS (Brazil)

    1994-12-31

    This work presents the structure of Gravatai Emergency Control Scheme (ECS) with short about its development and operation. This ECS was made to avoid two kinds of problems for the systems of Companhia Estadual de Energia Eletrica (CEEE). The first one is the voltage collapse that happens after the opening of one of the 525 kv LTs of the interconnection with the Brazilian Interconnected System (BIS). The second one is the CEEE isolating after the 525 kV network loss. We show the ECS existence reason and we describe its functional structure, the substations, the circuits and the amount of load shedding involved by the system. Finally, we present the project of a control structure based on microcomputer which is being developed for this ECS. (author) 3 refs., 11 figs.

  8. An analysis of control scheme and test results of fast feedback power supply

    International Nuclear Information System (INIS)

    Gupta, Shivam Kumar; Gupta, C.N.; Shah, Kunal; Makwana, Moti

    2017-01-01

    Real time Plasma Position Control is essential for obtaining long duration plasma in tokamaks. For that purpose four external coils has been installed in toroidal direction. Magnetic field of these coils interact with the plasma and tries to keep it radially stable in vacuum vessel to avoid direct contact of plasma to wall of tokamak. A fast feedback power supply has been installed in Aditya Tokamak which is able to set the appropriate current in either direction and current magnitude in external coils on the fast scale. In this paper, an analysis of control scheme and testing of Fast Feedback Power Supply (FFPS) has been described. FFPS is IGBT based H-bridge inverter programmable power supply

  9. A master-follower type distributed scheme for reactor inlet temperature control

    International Nuclear Information System (INIS)

    Garcia, H.E.; Dean, E.M.; Vilim, R.B.

    1995-01-01

    This paper describes the implementation of a computer-based controller for regulating reactor inlet temperature in a pool-type power plant. The elements of the control system are organized in a master-follower hierarchical architecture that takes advantage of existing in-plant hardware and software to minimize the need for plant modifications. Low level control algorithms are executed on existing local digital controllers (followers) with the high level algorithms executed on a new plant supervisory computer (master). A distributed computing strategy provides integration of the existing and additional computer platforms. The control system operates by having the master controller first estimate the secondary sodium flow needed to achieve a given reactor inlet temperature. The estimated flow is then used as a setpoint by the follower controller to regulate sodium flow using a motor-generator pump set. The control system has been implemented in a Hardware-In-the-Loop (FM) setup and qualified for operation in the Experimental Breader reactor 11 of Argonne National Laboratory. Some HIL results are provided

  10. Upgrading the Reactor Power Control Concept with a Modern Digital Control System

    International Nuclear Information System (INIS)

    Laengle, M.; Schildheuer, R.

    2011-01-01

    Within the framework of a retrofit project, a reactor power instrumentation and control system (REALL) - consisting of a limiting system and the respective reactor control systems - was retrofitted and modernized in a 1450-MW-nuclear-power-plant in Baden-Wuerttemberg. The REALL process control functions were implemented within a modern and completely digitized control system that has been designed for use in safety I and C applications. Along with the installation of the digital control system, the associated hardware was adapted to today's state of the art. At the same time, the given potential for improvement, as revealed during the plant's operation so far, was taken into account in the programming. In order to provide for transparent and quality-assured project management, the implementation was based on a stage plan consisting of several steps, along with specific milestones. Final commissioning of the modern digital control system took place during the 2008 plant overhaul. Despite the complex commissioning procedure, it was possible to avoid a major prolongation of the plant's downtime and to keep within a rough 4-week timeframe that had originally been defined for the plant overhaul to adequate structuring of the project, goal-oriented implementation of preparatory infrastructural measures and adequate scheduling of the coordinated activities of the installation and commissioning teams entrusted with the commissioning of the digital control system during the overhaul activities. (author)

  11. A novel walking speed estimation scheme and its application to treadmill control for gait rehabilitation

    Directory of Open Access Journals (Sweden)

    Yoon Jungwon

    2012-08-01

    Full Text Available Abstract Background Virtual reality (VR technology along with treadmill training (TT can effectively provide goal-oriented practice and promote improved motor learning in patients with neurological disorders. Moreover, the VR + TT scheme may enhance cognitive engagement for more effective gait rehabilitation and greater transfer to over ground walking. For this purpose, we developed an individualized treadmill controller with a novel speed estimation scheme using swing foot velocity, which can enable user-driven treadmill walking (UDW to more closely simulate over ground walking (OGW during treadmill training. OGW involves a cyclic acceleration-deceleration profile of pelvic velocity that contrasts with typical treadmill-driven walking (TDW, which constrains a person to walk at a preset constant speed. In this study, we investigated the effects of the proposed speed adaptation controller by analyzing the gait kinematics of UDW and TDW, which were compared to those of OGW at three pre-determined velocities. Methods Ten healthy subjects were asked to walk in each mode (TDW, UDW, and OGW at three pre-determined speeds (0.5 m/s, 1.0 m/s, and 1.5 m/s with real time feedback provided through visual displays. Temporal-spatial gait data and 3D pelvic kinematics were analyzed and comparisons were made between UDW on a treadmill, TDW, and OGW. Results The observed step length, cadence, and walk ratio defined as the ratio of stride length to cadence were not significantly different between UDW and TDW. Additionally, the average magnitude of pelvic acceleration peak values along the anterior-posterior direction for each step and the associated standard deviations (variability were not significantly different between the two modalities. The differences between OGW and UDW and TDW were mainly in swing time and cadence, as have been reported previously. Also, step lengths between OGW and TDW were different for 0.5 m/s and 1.5 m/s gait velocities

  12. Voltage Control Scheme with Distributed Generation and Grid Connected Converter in a DC Microgrid

    Directory of Open Access Journals (Sweden)

    Jong-Chan Choi

    2014-10-01

    Full Text Available Direct Current (DC microgrids are expected to become larger due to the rapid growth of DC energy sources and power loads. As the scale of the system expends, the importance of voltage control will be increased to operate power systems stably. Many studies have been performed on voltage control methods in a DC microgrid, but most of them focused only on a small scale microgrid, such as a building microgrid. Therefore, a new control method is needed for a middle or large scale DC microgrid. This paper analyzes voltage drop problems in a large DC microgrid and proposes a cooperative voltage control scheme with a distributed generator (DG and a grid connected converter (GCC. For the voltage control with DGs, their location and capacity should be considered for economic operation in the systems. Accordingly, an optimal DG allocation algorithm is proposed to minimize the capacity of a DG for voltage control in DC microgrids. The proposed methods are verified with typical load types by a simulation using MATLAB and PSCAD/EMTDC.

  13. Wire rope tension control of hoisting systems using a robust nonlinear adaptive backstepping control scheme.

    Science.gov (United States)

    Zhu, Zhen-Cai; Li, Xiang; Shen, Gang; Zhu, Wei-Dong

    2018-01-01

    This paper concerns wire rope tension control of a double-rope winding hoisting system (DRWHS), which consists of a hoisting system employed to realize a transportation function and an electro-hydraulic servo system utilized to adjust wire rope tensions. A dynamic model of the DRWHS is developed in which parameter uncertainties and external disturbances are considered. A comparison between simulation results using the dynamic model and experimental results using a double-rope winding hoisting experimental system is given in order to demonstrate accuracy of the dynamic model. In order to improve the wire rope tension coordination control performance of the DRWHS, a robust nonlinear adaptive backstepping controller (RNABC) combined with a nonlinear disturbance observer (NDO) is proposed. Main features of the proposed combined controller are: (1) using the RNABC to adjust wire rope tensions with consideration of parameter uncertainties, whose parameters are designed online by adaptive laws derived from Lyapunov stability theory to guarantee the control performance and stability of the closed-loop system; and (2) introducing the NDO to deal with uncertain external disturbances. In order to demonstrate feasibility and effectiveness of the proposed controller, experimental studies have been conducted on the DRWHS controlled by an xPC rapid prototyping system. Experimental results verify that the proposed controller exhibits excellent performance on wire rope tension coordination control compared with a conventional proportional-integral (PI) controller and adaptive backstepping controller. Copyright © 2017 ISA. All rights reserved.

  14. Additional cash incentive within a conditional cash transfer scheme: a 'controlled before and during' design evaluation study from India.

    Science.gov (United States)

    Lahariya, Chandrakant; Mishra, Ashok; Nandan, Deoki; Gautam, Praveen; Gupta, Sanjay

    2011-01-01

    Conditional Cash Transfer (CCT) schemes have shown largely favorable changes in the health seeking behavior. This evaluation study assesses the process and performance of an Additional Cash Incentive (ACI) scheme within an ongoing CCT scheme in India, and document lessons. A controlled before and during design study was conducted in Madhya Pradesh state of India, from August 2007 to March 2008, with increased in institutional deliveries as a primary outcome. In depth interviews, focus group discussions and household surveys were done for data collection. Lack of awareness about ACI scheme amongst general population and beneficiaries, cumbersome cash disbursement procedure, intricate eligibility criteria, extensive paper work, and insufficient focus on community involvement were the major implementation challenges. There were anecdotal reports of political interference and possible scope for corruption. At the end of implementation period, overall rate of institutional deliveries had increased in both target and control populations; however, the differences were not statistically significant. No cause and effect association could be proven by this study. Poor planning and coordination, and lack of public awareness about the scheme resulted in low utilization. Thus, proper IEC and training, detailed implementation plan, orientation training for implementer, sufficient budgetary allocation, and community participation should be an integral part for successful implementation of any such scheme. The lesson learned this evaluation study may be useful in any developing country setting and may be utilized for planning and implementation of any ACI scheme in future.

  15. Piezoelectric actuator based phase locking system to improve the dynamics of the control scheme for a heavy ion superconducting linac

    Energy Technology Data Exchange (ETDEWEB)

    Sahu, B.K., E-mail: bhuban@iuac.res.in [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India); Ahuja, R.; Kumar, Rajesh; Suman, S.K.; Mathuria, D.S.; Rai, A.; Patra, P.; Pandey, A.; Karmakar, J.; Chowdhury, G.K.; Dutt, R.N. [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India); Joshi, G. [Electronics Division, Bhabha Atomic Research Centre, Mumbai – 400 085 (India); Ghosh, S.; Kanjilal, D.; Roy, A. [Inter University Accelerator Centre (IUAC), Aruna Asaf Ali Marg, New Delhi – 110 067 (India)

    2015-03-21

    The superconducting heavy ion linear accelerator at Inter-University Accelerator Centre Delhi has been in operation since 2007. Initially, the superconducting niobium Quarter Wave Resonators (QWRs) in the linac were phase locked using a combination of electronic and mechanical controls which operated in fast (~10 μsec) and slow (~sec) time scales respectively. In this scheme, fast control was achieved through dynamic phase control whereas slow control of the frequency was done through the niobium tuner bellows installed at the drift tube end of the resonator and flexed using helium gas to change the resonance frequency. In order to improve the dynamics of this control system, an alternate scheme using piezoelectric actuator, instead of helium gas, to flex the same niobium bellows, has been implemented in the QWRs of the second and third accelerating modules of the linac. The piezoelectric actuator is used in closed loop along with the fast dynamic phase control scheme. The feedback loop of the piezoelectric control includes a dual control scheme - an integral control loop to arrest the slow drift, and the positive position feedback (PPF) based control loop to damp the microphonics. This control scheme has been found to arrest slow drifts in the resonator frequency more tightly along with damping of low frequency microphonics (~few tens of Hz) picked up by the resonator from its surrounding environment. This has substantially eased the load from the fast electronic control, resulting in the reduction of the radio frequency (RF) power requirement during operation. In addition, it has improved the stability of phase and amplitude of the QWRs. The details of the new scheme along with results obtained during the online run of the linac for beam acceleration are presented.

  16. Impact of Smoke Exposure on Digital Instrumentation and Control

    International Nuclear Information System (INIS)

    Tanaka, Tina J.; Nowlen, Steven P.; Korsah, Kofi; Wood, Richard T.; Antonescu, Christina E.

    2003-01-01

    Smoke can cause interruptions and upsets in active electronics. Because nuclear power plants are replacing analog with digital instrumentation and control systems, qualification guidelines for new systems are being reviewed for severe environments such as smoke and electromagnetic interference. Active digital systems, individual components, and active circuits have been exposed to smoke in a program sponsored by the U.S. Nuclear Regulatory Commission. The circuits and systems were all monitored during the smoke exposure, indicating any immediate effects of the smoke. The results of previous smoke exposure studies have been reported in various publications. The major immediate effect of smoke has been to increase leakage currents and to cause momentary upsets and failures in digital systems. This paper presents new results from conformal coatings, memory chips, and hard drive tests.The best conformal coatings were found to be polyurethane, parylene, and acrylic (when applied by dipping). Conformal coatings can reduce smoke-induced leakage currents and protect against metal loss through corrosion. However conformal coatings are typically flammable, so they do increase material flammability. Some of the low-voltage biased memory chips failed during a combination of high smoke and high humidity. Typically, smoke along with heat and humidity is expected during fire, rather than smoke alone. Thus, due to high sensitivity of digital circuits to heat and humidity, it is hypothesized that the impact of smoke may be secondary.Low-voltage (3.3-V) static random-access memory (SRAMs) were found to be the most vulnerable to smoke. Higher bias voltages decrease the likelihood of failure. Erasable programmable read-only memory (EPROMs) and nonvolatile SRAMs were very smoke tolerant. Failures of the SRAMs occurred when two conditions were present: high density of smoke and high humidity. As the high humidity was present for only part of the test, the failures were intermittent. All

  17. Control and monitoring of doses to patients in a team of digital mammography; Control y seguimiento de las dosis a pacientes en un equipo de mamografia digital

    Energy Technology Data Exchange (ETDEWEB)

    Agulla Otero, M.; Torres Cabrera, R.; Hernando Gonzalez, I.

    2013-07-01

    In recent years is widespread use of imaging devices digital mammography. One of the advantages associated with this scanning is the ability to access a large amount of information contained in the headwaters of own digital images. The exploitation of this information allows the calculation of doses received by patients. This paper describes the methodology employed for this purpose and are presented the results of the control and monitoring of doses given in a digital mammography equipment. (Author)

  18. Photovoltaic System Equipped with Digital Command Control and Acquisition

    Directory of Open Access Journals (Sweden)

    Khalil Kassmi

    2013-07-01

    Full Text Available In this paper, we present results concerning the design, the realization and the characterization of a photovoltaic system (PV, equipped with a digital controls: Power Point Tracking (MPPT, charge/discharge lead acid batteries, sun tracker and supervision. These different functions are performed with a microcontroller that has capabilities and functions to the reliability of PV systems (signal generation Pulses Width Modulation (PWM, speed etc.. Concerning the MPPT control operation, we improved the accuracy and reliability of research by improving the search algorithm “Hill Climbing” taking into account the optimal operation of PV panels depending on weather conditions (temperature and light.The experiment of each block shows that the MPPT control converges instantly the operating point of the PV panels around the maximum power point, independently of sudden changes of the illumination or the load. The control blocks charge/discharge battery and sun tracking show good control of charge/discharge lead acid batteries and the need of sun tracker to increase the power supplied by the PV panel. By using the improved MPPT control, loss of power supplied by the PV panels are very low (below 5%.

  19. Scheme for improving laser stability via feedback control of intracavity nonlinear loss.

    Science.gov (United States)

    Jin, Pixian; Lu, Huadong; Su, Jing; Peng, Kunchi

    2016-05-01

    We present a novel and efficient scheme to enhance the stability of laser output via feedback control to a nonlinear loss deliberately introduced to the laser resonator. By means of the feedback control to the intracavity nonlinear loss of an all-solid-state continuous-wave single-frequency laser with high output power at 1064 nm, its intensity and frequency stabilities are significantly improved. A lithium triborate crystal is deliberately placed inside the laser resonator to be an element of the nonlinear loss, and the temperature of the crystal is feedback controlled by an electronic loop. The control signal is generated by distinguishing the deviation of the output power and used for manipulating the intracavity nonlinear loss to compensate the deviation of the laser power actively. With the feedback-control loop, the intensity and frequency fluctuations of the output laser at 1064 nm are reduced from ±0.59% and 21.82 MHz without the feedback to ±0.26% and 9.84 MHz, respectively.

  20. Definition of a Robust Supervisory Control Scheme for Sodium-Cooled Fast Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Ponciroli, R.; Passerini, S.; Vilim, R. B.

    2016-04-17

    In this work, an innovative control approach for metal-fueled Sodium-cooled Fast Reactors is proposed. With respect to the classical approach adopted for base-load Nuclear Power Plants, an alternative control strategy for operating the reactor at different power levels by respecting the system physical constraints is presented. In order to achieve a higher operational flexibility along with ensuring that the implemented control loops do not influence the system inherent passive safety features, a dedicated supervisory control scheme for the dynamic definition of the corresponding set-points to be supplied to the PID controllers is designed. In particular, the traditional approach based on the adoption of tabulated lookup tables for the set-point definition is found not to be robust enough when failures of the implemented SISO (Single Input Single Output) actuators occur. Therefore, a feedback algorithm based on the Reference Governor approach, which allows for the optimization of reference signals according to the system operating conditions, is proposed.

  1. Robust Networked Control Scheme for Distributed Secondary Control of Islanded MicroGrids

    DEFF Research Database (Denmark)

    Shafiee, Qobad; Stefanovic, Cedomir; Dragicevic, Tomislav

    2014-01-01

    Distributed secondary control (DSC) is a new approach for microgrids (MGs) by which the frequency, voltage and power can be regulated by using only local unit controllers. Such a solution is necessary for anticipated scenarios that have an increased number of distributed generators (DGs) within t...

  2. Simple Digital Control of a Two-Stage PFC Converter Using DSPIC30F Microprocessor

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2010-01-01

    The use of dsPIC digital signal controllers (DSC) in Switch Mode Power Supply (SMPS) applications opens new perspectives for cheap and flexible digital control solutions. This paper presents the digital control of a two stage power factor corrector (PFC) converter. The PFC circuit is designed...... and built for 70W rated output power. Average current mode control for boost converter and current programmed control for forward converter are implemented on a dsPIC30F1010. Pulse Width Modulation (PWM) technique is used to drive the switching MOSFETs. Results show that digital solutions with ds...

  3. MAPLE-X10 reactor digital control system

    International Nuclear Information System (INIS)

    Deverno, M.T.; Hinds, H.W.

    1991-10-01

    The MAPLE-X10 reactor, currently under construction at the Chalk River Laboratories of Atomic Energy of Canada Limited, is a 10 MW t , pool-type, light-water reactor. It will be used for radioisotope production and silicon neutron transmutation doping. The reactor is controlled by a Digital Control System (DCS) and protected against abnormal process events by two independent safety systems. The DCS is an integrated control system used to regulate the reactor power and process systems. The safety philosophy for the control system is to minimize unsafe events arising from system failures and operational errors. this is achieved through redundancy, fail-safe design, automatic fault detection, and the selection of highly reliable components. The DCS provides both computer-controlled reactor regulation from the shutdown state to full power and automated reactor shutdown if safe limits are exceeded or critical sensors malfunction. The use of commercially available hardware with enhanced quality assurance makes the system cost effective while providing a high degree of reliability

  4. Semiactive balancing control scheme in a rotor - bearing system supported on Mr. Dampers: design and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Silva Navarro, Gerardo; Cabrera Amado, Alvaro [Cinvestav, IPN, Mexico, D.F. (Mexico)

    2007-11-15

    This paper deals with the problem of semiactive balancing control of a rotor-bearing system, where one journal bearings is supported on two radial Magneto-Rheological (MR) dampers. The mathematical model of the rotor-bearing system results from an orthotropic Jeffcott-like model and the dynamics associated to the MR dampers, whose rheological properties depend on the current inputs. For control purposes we use the Choi-Lee-Park polynomial for the MR dampers, which is quite consistent with the tpical nonlinear and complex hysteresis behavior and also simplifies the physical implementation on an experimental setup. The semiactive control scheme for the unbalance reponse of the rotor-bearing system is synthesized using sliding-mode control techniques. Some numerical and experimental results are included to illustrate the dynamic performance and robustness of the overall system. [Spanish] En este trabajo se abora el problema de control semiactivo del desbalance en un sistema rotor-chumacera, donde una de las chumaceras convencionales se monta sobre una suspension con dos amortiguadores Magneto-Reologicos (MR) radiales. El modelo matematico del sistema rotorchumacera se obtiene de un modelo tipo Jefcott ortotropico y la dinamica de los amortiguadores MR, cuyas propiedades reologicas dependen de las corrientes electricas de alimentacion. Para propositos de control se emplea el modelo polinomial de Choi-Lee-Park para los dos amortiguadores MR, el cual es consistente con el tipico comportamiento no-lineal y de histeresis, permitiendo simplificar su implementacion fisica en una plataforma experimental. El esquema de control semiactivo de la respuesta al desbalance, en el sistema rotor-chumacera, se basa en las tecnicas de control por modos deslizantes. Se presentan algunos resultados de simulacion numerica y experimentos que utilizan el funcionamiento y robustez del sistema completo.

  5. On the Need of Novel Medium Access Control Schemes for Network Coding enabled Wireless Mesh Networks

    DEFF Research Database (Denmark)

    Paramanathan, Achuthan; Pahlevani, Peyman; Roetter, Daniel Enrique Lucani

    2013-01-01

    to the incoming and outgoing packet ratio. We describe the new protocol as an extension to the CSMA/CA protocol and implement the protocol on our own hardware platform. By means of our own testbed, we investigate two basic network structures, namely, the two-way relay and the cross topology. It is well known...... that network coding will improve the throughput in such systems, but our novel medium access scheme improves the performance in the cross topology by another 66 % for network coding and 150 % for classical forwarding in theory. These gains translate in a theoretical gain of 33 % of network coding over......This paper advocates for a new Medium Access Control (MAC) strategy for wireless meshed networks by identifying overload scenarios in order to provide additional channel access priority to the relay. The key behind our MAC protocol is that the relay will adjust its back off window size according...

  6. Enhanced signaling scheme with admission control in the hybrid optical wireless (HOW) networks

    DEFF Research Database (Denmark)

    Yan, Ying; Yu, Hao; Wessing, Henrik

    2009-01-01

    that it can support stringent Quality of Service (QoS) requirements. In this paper, we describe and evaluate a resource management framework designed for the HOW networks. There are two parts in the resource management framework The first part is the Enhanced MPCP (E-MPCP) scheme aiming at improving signaling......The hybrid optical wireless (HOW) network has been viewed as a promising solution to meet the increasing user bandwidth and mobility demands. Due to the basic differences in the optical and wireless technologies, a challenging problem lies in the Media Access Control (MAC) protocol design so...... dropping probability depend on several factors. These factors include the frame duration, the traffic load and the total number of shared users. The results also highlight that our proposed system achieves significant improvements over the traditional approach in terms of user QoS guarantee and network...

  7. Performance Analysis of Savonius Rotor Based Hydropower Generation Scheme with Electronic Load Controller

    Directory of Open Access Journals (Sweden)

    Rajen Pudur

    2016-01-01

    Full Text Available This paper describes the performance of electronic load controller (ELC of asynchronous generator (AG coupled to an uncontrolled Savonius turbine and variable water velocity. An AC-DC-AC converter with a dc link capacitor is employed to maintain the required frequency. The ELC which is feeding a resistive dump load is connected in parallel with the generating system and the power consumption is varied through the duty cycle of the chopper. Gate triggering of ELC is accomplished through sinusoidal pulse width modulation (SPWM by sensing the load current. A MATLAB/Simulink model of Savonius rotor, asynchronous generator, ELC, and three-phase load is presented. The proposed scheme is tested under various load conditions under varying water velocities and the performances are observed to be satisfactory.

  8. Digital Pulse Modulation Amplifier (PMA) systems based on PEDEC control

    DEFF Research Database (Denmark)

    Nielsen, Karsten

    1999-01-01

    The paper extends previous research and presents a suite of novel high efficiency digital PMA topologies based on Pulse Edge Delay Error Correction (PEDEC). The practical results are very encouraging, showing that digital modulator performance is maintained throughout the subsequent power...... conversion. The topologies are believed to be the first implemented digital PMA systems including effective power stage error correction....

  9. Formulation of a strategy for monitoring control integrity in critical digital control systems

    Science.gov (United States)

    Belcastro, Celeste M.; Fischl, Robert; Kam, Moshe

    1991-01-01

    Advanced aircraft will require flight critical computer systems for stability augmentation as well as guidance and control that must perform reliably in adverse, as well as nominal, operating environments. Digital system upset is a functional error mode that can occur in electromagnetically harsh environments, involves no component damage, can occur simultaneously in all channels of a redundant control computer, and is software dependent. A strategy is presented for dynamic upset detection to be used in the evaluation of critical digital controllers during the design and/or validation phases of development. Critical controllers must be able to be used in adverse environments that result from disturbances caused by an electromagnetic source such as lightning, high intensity radiated field (HIRF), and nuclear electromagnetic pulses (NEMP). The upset detection strategy presented provides dynamic monitoring of a given control computer for degraded functional integrity that can result from redundancy management errors and control command calculation error that could occur in an electromagnetically harsh operating environment. The use is discussed of Kalman filtering, data fusion, and decision theory in monitoring a given digital controller for control calculation errors, redundancy management errors, and control effectiveness.

  10. Observerless Scheme for Sensorless Speed Control of PMSM Using Direct Torque Control Method With LP Filter

    OpenAIRE

    BEKIROGLU, N.; OZCIRA, S.

    2010-01-01

    In this study, direct torque control (DTC) of a permanent magnet synchronous motor is realized with a sensorless speed control technique without using an observer. Space vector pulse width modulation (SVPWM) technique is applied in order to determine the switching sequence of the voltage source inverter. Torque and flux, the main variables of the DTC, are estimated by using the mathematical model of the motor. Estimated torque and flux values are compared with their references in every con...

  11. Design and implementation of adaptive PI control schemes for web tension control in roll-to-roll (R2R) manufacturing.

    Science.gov (United States)

    Raul, Pramod R; Pagilla, Prabhakar R

    2015-05-01

    In this paper, two adaptive Proportional-Integral (PI) control schemes are designed and discussed for control of web tension in Roll-to-Roll (R2R) manufacturing systems. R2R systems are used to transport continuous materials (called webs) on rollers from the unwind roll to the rewind roll. Maintaining web tension at the desired value is critical to many R2R processes such as printing, coating, lamination, etc. Existing fixed gain PI tension control schemes currently used in industrial practice require extensive tuning and do not provide the desired performance for changing operating conditions and material properties. The first adaptive PI scheme utilizes the model reference approach where the controller gains are estimated based on matching of the actual closed-loop tension control systems with an appropriately chosen reference model. The second adaptive PI scheme utilizes the indirect adaptive control approach together with relay feedback technique to automatically initialize the adaptive PI gains. These adaptive tension control schemes can be implemented on any R2R manufacturing system. The key features of the two adaptive schemes is that their designs are simple for practicing engineers, easy to implement in real-time, and automate the tuning process. Extensive experiments are conducted on a large experimental R2R machine which mimics many features of an industrial R2R machine. These experiments include trials with two different polymer webs and a variety of operating conditions. Implementation guidelines are provided for both adaptive schemes. Experimental results comparing the two adaptive schemes and a fixed gain PI tension control scheme used in industrial practice are provided and discussed. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  12. Design of a Control Scheme for Distribution Static Synchronous Compensators with Power-Quality Improvement Capability

    Directory of Open Access Journals (Sweden)

    Pedro Roncero-Sànchez

    2014-04-01

    Full Text Available Electric power systems are among the greatest achievements of the last century. Today, important issues, such as an ever-increasing demand, the flexible and reliable integration of distributed generation or a growth in disturbing loads, must be borne in mind. In this context, smart grids play a key role, allowing better efficiency of power systems. Power electronics provides solutions to the aforementioned matters, since it allows various energy sources to be integrated into smart grids. Nevertheless, the design of the various control schemes that are necessary for the correct operation of the power-electronic interface is a very important issue that must always be taken into consideration. This paper deals with the design of the control system of a distribution static synchronous compensator (DSTATCOM based on flying-capacitor multilevel converters. The control system is tailored to compensate for both voltage sags by means of reactive-power injection and voltage imbalances caused by unbalanced loads. The design of the overall control is carried out by using the root-locus and frequency-response techniques, improving both the transient response and the steady-state error of the closed-loop system. Simulation results obtained using PSCADTM/EMTDCTM (Manitoba Hydro International Ltd., Commerce Drive, Winnipeg, MB, Canada show the resultant voltage regulation.

  13. Control Scheme Formulation for the Production of Hydrogen on Demand to Feed an Internal Combustion Engine

    Directory of Open Access Journals (Sweden)

    Jarniel García Morales

    2016-12-01

    Full Text Available In this work, a control strategy is presented to produce hydrogen on demand to feed an internal combustion (IC engine. For this purpose, the modeling of the IC engine fueled by gasoline blended with 10 % v/v of anhydrous ethanol (E10 and hydrogen as an additive is developed. It is considered that the hydrogen gas is produced according to the IC engine demand, and that the hydrogen gas is obtained by an alkaline electrolyzer. The gasoline–ethanol blend added into the combustion chamber is determined according to the stoichiometric ratio and the production of hydrogen gas is regulated by a proportional and integral controller (P.I.. The controller reference is varying according to the mass flow air induced into the cylinder, in order to ensure an adequate production of hydrogen gas for any operating condition of the IC engine. The main contribution of this work is the control scheme developed, through simulation, in order to produce hydrogen on demand for any operating point of an internal combustion engine fueled by an E10 blend. The simulation results showed that the use of hydrogen gas as an additive in an E10 blend decreases the E10 fuel consumption 23 % on average, and the thermal efficiency is increased approximately 2.13 % , without brake power loss in the IC engine.

  14. Particle beam digital phase control system for COSY

    International Nuclear Information System (INIS)

    Schnase, A.

    1994-02-01

    Particle accelerators require that the orbit of the charged particles in the vacuum chamber is controlled to fulfil narrow limits. This is done by magnetic deflection systems and exactly adjusted rf-acceleration. Up to now the necessary control-functions were realised with analogue parts. This work describes a digital phase control system that works in real time and is used with the proton accelerator COSY. The physical design of the accelerator sets the accuracy-specifications of the revolution frequency (<1 Hz in the whole range from 400 kHz to 1.6 MHz), the phase-difference (<0.01 ), the signal-to-noise-ratio (<-60 dBc) and the update rate (<1 μs) of the parameters. In a typical operation the beam is first bunched and synchronised to the reference oscillator. After that the beam influences the rf-system with the help of charge detectors and now the rf-systems will be synchronised with the bunched beam. This control-loop is modelled and simulated with PSPICE. (orig.)

  15. Quality control of the interpretation monitors of digital radiological images

    International Nuclear Information System (INIS)

    Favero, Mariana S.; Goulart, Adriano Oliveira S.

    2016-01-01

    The performance monitors has great importance in image quality of digital radiographic systems. In environments without films, it became necessary to implement acceptance testing and quality control monitors used for interpretation of medical images. The monitors dedicated to radiodiagnostic should provide information that represent slight differences in x-ray attenuation or minor differences in some anatomical region of interest. This should also result in small differences in luminance of an image represented. Factors affecting the quality of medical imaging are contrast, noise, resolution, artifacts and distortions. Therefore, a monitor must have specific characteristics, making it possible for the observer to carry out an assessment that leads to better diagnosis. Based on the need to evaluate diagnostic monitors in various radiological applications, this paper presents a summary for implementation and standardization of tests that are recommended by the publication AAPM Report 03. (author)

  16. Application of Genetic Control with Adaptive Scaling Scheme to Signal Acquisition in Global Navigation Satellite System Receiver

    Directory of Open Access Journals (Sweden)

    Ho-Nien Shou

    2012-02-01

    Full Text Available This paper presents a genetic-based control scheme that not only utilizes evolutionary characteristics to find the signal acquisition parameters, but also employs an adaptive scheme to control the search space and avoid the genetic control converging to local optimal value so as to acquire the desired signal precisely and rapidly. Simulations and experiment results show that the proposed method can improve the precision of signal parameters and take less signal acquisition time than traditional serial search methods for global navigation satellite system (GNSS signals.

  17. A Digital Motion Control System for Large Telescopes

    Science.gov (United States)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.

    2001-05-01

    We have designed and programmed a digital motion control system for large telescopes, in particular, the 6-meter antennas of the Submillimeter Array on Mauna Kea. The system consists of a single robust, high-reliability microcontroller board which implements a two-axis velocity servo while monitoring and responding to critical safety parameters. Excellent tracking performance has been achieved with this system (0.3 arcsecond RMS at sidereal rate). The 24x24 centimeter four-layer printed circuit board contains a multitude of hardware devices: 40 digital inputs (for limit switches and fault indicators), 32 digital outputs (to enable/disable motor amplifiers and brakes), a quad 22-bit ADC (to read the motor tachometers), four 16-bit DACs (that provide torque signals to the motor amplifiers), a 32-LED status panel, a serial port to the LynxOS PowerPC antenna computer (RS422/460kbps), a serial port to the Palm Vx handpaddle (RS232/115kbps), and serial links to the low-resolution absolute encoders on the azimuth and elevation axes. Each section of the board employs independent ground planes and power supplies, with optical isolation on all I/O channels. The processor is an Intel 80C196KC 16-bit microcontroller running at 20MHz on an 8-bit bus. This processor executes an interrupt-driven, scheduler-based software system written in C and assembled into an EPROM with user-accessible variables stored in NVSRAM. Under normal operation, velocity update requests arrive at 100Hz from the position-loop servo process running independently on the antenna computer. A variety of telescope safety checks are performed at 279Hz including routine servicing of a 6 millisecond watchdog timer. Additional ADCs onboard the microcontroller monitor the winding temperature and current in the brushless three-phase drive motors. The PID servo gains can be dynamically changed in software. Calibration factors and software filters can be applied to the tachometer readings prior to the application of

  18. The Digital Motion Control System for the Submillimeter Array Antennas

    Science.gov (United States)

    Hunter, T. R.; Wilson, R. W.; Kimberk, R.; Leiker, P. S.; Patel, N. A.; Blundell, R.; Christensen, R. D.; Diven, A. R.; Maute, J.; Plante, R. J.; Riddle, P.; Young, K. H.

    2013-09-01

    We describe the design and performance of the digital servo and motion control system for the 6-meter parabolic antennas of the Submillimeter Array (SMA) on Mauna Kea, Hawaii. The system is divided into three nested layers operating at a different, appropriate bandwidth. (1) A rack-mounted, real-time Unix system runs the position loop which reads the high resolution azimuth and elevation encoders and sends velocity and acceleration commands at 100 Hz to a custom-designed servo control board (SCB). (2) The microcontroller-based SCB reads the motor axis tachometers and implements the velocity loop by sending torque commands to the motor amplifiers at 558 Hz. (3) The motor amplifiers implement the torque loop by monitoring and sending current to the three-phase brushless drive motors at 20 kHz. The velocity loop uses a traditional proportional-integral-derivative (PID) control algorithm, while the position loop uses only a proportional term and implements a command shaper based on the Gauss error function. Calibration factors and software filters are applied to the tachometer feedback prior to the application of the servo gains in the torque computations. All of these parameters are remotely adjustable in the software. The three layers of the control system monitor each other and are capable of shutting down the system safely if a failure or anomaly occurs. The Unix system continuously relays the antenna status to the central observatory computer via reflective memory. In each antenna, a Palm Vx hand controller displays the complete system status and allows full local control of the drives in an intuitive touchscreen user interface. The hand controller can also be connected outside the cabin, a major convenience during the frequent reconfigurations of the interferometer. Excellent tracking performance ( 0.3‧‧ rms) is achieved with this system. It has been in reliable operation on 8 antennas for over 10 years and has required minimal maintenance.

  19. 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

    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...

  20. An Enhanced Dual Droop Control Scheme for Resilient Active Power Sharing among Paralleled Two-Stage Converters

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

    2017-01-01

    Traditional droop-controlled system has assumed that generators can always generate the powers demanded from them. This is true with conventional sources, where fuel supplies are usually planned in advance. For renewable sources, it may also be possible if energy storage is available. Energy...... cases, traditional droop scheme may not work well when its demanded power cannot be met by some renewable sources due to intermittency. When that happens, the system may become unstable with some sources progressively brought out of generation. To avoid such occurrence, an enhanced dual droop scheme...... is proposed for general two-stage converters with front rectifiers or dc-dc converters for conditioning powers from renewable sources and rear inverters for channeling powers to remote grids. Unlike the traditional droop scheme, the proposed dual droop scheme uses both dc-link voltage and generated powers...

  1. Coordinated Control Scheme of Battery Energy Storage System (BESS) and Distributed Generations (DGs) for Electric Distribution Grid Operation

    DEFF Research Database (Denmark)

    Cha, Seung-Tae; Zhao, Haoran; Wu, Qiuwei

    2012-01-01

    This paper describes a coordinated control scheme of battery energy storage system (BESS) and distributed generations (DGs) for electric distribution grid operation. The BESS is designed to stabilize frequency and voltages as a primary control after the electric distribution system enters...

  2. Flexible aircraft control based on an adaptive output feedback control scheme

    OpenAIRE

    Bordeneuve-Guibé, Joël; Bako, Laurent; Miksch, Roland; Jeanneau, Matthieu

    2009-01-01

    One of the major challenges in aeronautical flexible structures control is the uncertain or the non stationary feature of the systems. Transport aircrafts are of unceasingly growing size but are made from increasingly light materials so that their motion dynamics present some flexible low frequency modes coupled to rigid modes. For reasons that range from fuel transfer to random flying conditions, the parameters of these planes may be subject to significative variations during a flight. A sin...

  3. An Enhanced Three-Level Voltage Switching State Scheme for Direct Torque Controlled Open End Winding Induction Motor

    Science.gov (United States)

    Kunisetti, V. Praveen Kumar; Thippiripati, Vinay Kumar

    2018-01-01

    Open End Winding Induction Motors (OEWIM) are popular for electric vehicles, ship propulsion applications due to less DC link voltage. Electric vehicles, ship propulsions require ripple free torque. In this article, an enhanced three-level voltage switching state scheme for direct torque controlled OEWIM drive is implemented to reduce torque and flux ripples. The limitations of conventional Direct Torque Control (DTC) are: possible problems during low speeds and starting, it operates with variable switching frequency due to hysteresis controllers and produces higher torque and flux ripple. The proposed DTC scheme can abate the problems of conventional DTC with an enhanced voltage switching state scheme. The three-level inversion was obtained by operating inverters with equal DC-link voltages and it produces 18 voltage space vectors. These 18 vectors are divided into low and high frequencies of operation based on rotor speed. The hardware results prove the validity of proposed DTC scheme during steady-state and transients. From simulation and experimental results, proposed DTC scheme gives less torque and flux ripples on comparison to two-level DTC. The proposed DTC is implemented using dSPACE DS-1104 control board interface with MATLAB/SIMULINK-RTI model.

  4. Optimal control, investment and utilization schemes for energy storage under uncertainty

    Science.gov (United States)

    Mirhosseini, Niloufar Sadat

    Energy storage has the potential to offer new means for added flexibility on the electricity systems. This flexibility can be used in a number of ways, including adding value towards asset management, power quality and reliability, integration of renewable resources and energy bill savings for the end users. However, uncertainty about system states and volatility in system dynamics can complicate the question of when to invest in energy storage and how best to manage and utilize it. This work proposes models to address different problems associated with energy storage within a microgrid, including optimal control, investment, and utilization. Electric load, renewable resources output, storage technology cost and electricity day-ahead and spot prices are the factors that bring uncertainty to the problem. A number of analytical methodologies have been adopted to develop the aforementioned models. Model Predictive Control and discretized dynamic programming, along with a new decomposition algorithm are used to develop optimal control schemes for energy storage for two different levels of renewable penetration. Real option theory and Monte Carlo simulation, coupled with an optimal control approach, are used to obtain optimal incremental investment decisions, considering multiple sources of uncertainty. Two stage stochastic programming is used to develop a novel and holistic methodology, including utilization of energy storage within a microgrid, in order to optimally interact with energy market. Energy storage can contribute in terms of value generation and risk reduction for the microgrid. The integration of the models developed here are the basis for a framework which extends from long term investments in storage capacity to short term operational control (charge/discharge) of storage within a microgrid. In particular, the following practical goals are achieved: (i) optimal investment on storage capacity over time to maximize savings during normal and emergency

  5. Digital System Categorization Methodology to Support Integration of Digital Instrumentation and Control Models into PRAs

    International Nuclear Information System (INIS)

    Arndt, Steven A.

    2011-01-01

    It has been suggested that by categorizing the various digital systems used in safety critical applications in nuclear power plants, it would be possible to determine which systems should be modeled in the analysis of the larger plant wide PRA, at what level of detail the digital system should be modeled and using which methods. The research reported in this paper develops a categorization method using system attributes to permit a modeler to more effectively model the systems that will likely have the most critical contributions to the overall plant safety and to more effectively model system interactions for those digital systems where the interactions are most important to the overall accuracy and completeness of the plant PRA. The proposed methodology will categorize digital systems based on certain attributes of the systems themselves and how they will be used in the specific application. This will help determine what digital systems need to be modeled and at what level of detail, and can be used to guide PRA analysis and regulatory reviews. The three-attribute categorization strategy that was proposed by Arndt is used as the basis for the categorization methodology developed here. The first attribute, digital system complexity, is based on Type Il interactions defined by Aldemir and an overall digital system size and complexity index. The size and complexity index used are previously defined software complexity metrics. Potential sub-attributes of digital system complexity include, design complexity, software complexity, hardware complexity, system function complexity and testability. The second attribute, digital system interactions/inter-conductivity, is a combination of Rushby's coupling and Ademir's Type I interactions. Digital systems that are loosely coupled and/or have very few Type I interaction would not interact dynamically with the overall system and would have a low interactions/inter-conductivity score. Potential sub-attributes of digital system

  6. Digital System Categorization Methodology to Support Integration of Digital Instrumentation and Control Models into PRAs

    Energy Technology Data Exchange (ETDEWEB)

    Arndt, Steven A. [U.S. Nuclear Regulatory Commission, Washington D.C. (United States)

    2011-08-15

    It has been suggested that by categorizing the various digital systems used in safety critical applications in nuclear power plants, it would be possible to determine which systems should be modeled in the analysis of the larger plant wide PRA, at what level of detail the digital system should be modeled and using which methods. The research reported in this paper develops a categorization method using system attributes to permit a modeler to more effectively model the systems that will likely have the most critical contributions to the overall plant safety and to more effectively model system interactions for those digital systems where the interactions are most important to the overall accuracy and completeness of the plant PRA. The proposed methodology will categorize digital systems based on certain attributes of the systems themselves and how they will be used in the specific application. This will help determine what digital systems need to be modeled and at what level of detail, and can be used to guide PRA analysis and regulatory reviews. The three-attribute categorization strategy that was proposed by Arndt is used as the basis for the categorization methodology developed here. The first attribute, digital system complexity, is based on Type Il interactions defined by Aldemir and an overall digital system size and complexity index. The size and complexity index used are previously defined software complexity metrics. Potential sub-attributes of digital system complexity include, design complexity, software complexity, hardware complexity, system function complexity and testability. The second attribute, digital system interactions/inter-conductivity, is a combination of Rushby's coupling and Ademir's Type I interactions. Digital systems that are loosely coupled and/or have very few Type I interaction would not interact dynamically with the overall system and would have a low interactions/inter-conductivity score. Potential sub-attributes of

  7. Closed-loop-controlled vortex shedding and vibration of a flexibly supported square cylinder under different schemes

    Science.gov (United States)

    Zhang, M. M.; Cheng, L.; Zhou, Y.

    2004-05-01

    Different schemes were experimentally investigated of the closed-loop control of vortex shedding from a spring-supported square cylinder in cross flow. The control action was implemented through the perturbation of one cylinder surface, which was generated by three piezoelectric ceramic actuators, embedded underneath the surface and controlled by a proportional-integral-derivative controller. Three control schemes were investigated using different feedback signals, including the turbulent flow signal measured by a hot wire, flow-induced structural oscillation signal obtained by a laser vibrometer, and a combination of both signals. An investigation was conducted at the resonance condition, when the vortex-shedding frequency coincided with the natural frequency of the fluid-structure system. The flow and structural vibration were measured using particle image velocimetry, laser-induced fluorescence flow visualization, a laser Doppler anemometer, and a laser vibrometer. It was observed that the control scheme based on the feedback of both flow and structural oscillation led to the almost complete destruction of the Kármán vortex street and a reduction in the structural vibration, vortex shedding strength, and drag coefficient by 82%, 65%, and 35%, respectively, outperforming by far an open-loop control as well as the other two closed-loop schemes.

  8. Simplified false-positive reduction in computer-aided detection scheme of clustered microcalcifications in digital breast tomosynthesis

    Science.gov (United States)

    Jeong, Ji-Wook; Chae, Seung-Hoon; Lee, Sooyeul; Chae, Eun Young; Kim, Hak Hee; Choi, Young-Wook

    2015-03-01

    A computer-aided detection (CADe) system for clustered microcalcifications (MCs) in reconstructed digital breast tomosynthesis (DBT) volumes was suggested. The system consisted of prescreening, MC detecting, clustering, and falsepositive reduction steps. In the prescreening stage, the MC-like objects were enhanced by a multiscale-based 3D calcification response function. A connected component segmentation method was used to detect cluster seed objects, which were considered as potential clustering centers of MCs. Starting with each cluster seed object as the initial cluster center, a cluster candidate was formed by including nearby MC candidates within a 3D neighborhood of the cluster seed object satisfying the clustering criteria during the clustering step. The size and number of the clustered MCs in a cluster seed candidate were used to reduce the number of FPs. A bounding cube for each MCC was generated for each accepted seed candidates. Then, the overlapping cubes were combined and examined according to the FP reduction criteria. After FP reduction step, we obtained the average number of FPs of 2.47 per DBT volume with sensitivity of 83.3%. Our study indicates the simplified false-positive reduction approach applied to the detection of clustered MCs in DBT is promising as an efficient CADe system.

  9. Computer aided design of digital controller for radial active magnetic bearings

    Science.gov (United States)

    Cai, Zhong; Shen, Zupei; Zhang, Zuming; Zhao, Hongbin

    1992-01-01

    A five degree of freedom Active Magnetic Bearing (AMB) system is developed which is controlled by digital controllers. The model of the radial AMB system is linearized and the state equation is derived. Based on the state variables feedback theory, digital controllers are designed. The performance of the controllers are evaluated according to experimental results. The Computer Aided Design (CAD) method is used to design controllers for magnetic bearings. The controllers are implemented with a digital signal processing (DSP) system. The control algorithms are realized with real-time programs. It is very easy to change the controller by changing or modifying the programs. In order to identify the dynamic parameters of the controlled magnetic system, a special experiment was carried out. Also, the online Recursive Least Squares (RLS) parameter identification method is studied. It can be realized with the digital controllers. Online parameter identification is essential for the realization of an adaptive controller.

  10. Development of an Optimal Power Control Scheme for Wave-Offshore Hybrid Generation Systems

    Directory of Open Access Journals (Sweden)

    Seungmin Jung

    2015-08-01

    Full Text Available Integration technology of various distribution systems for improving renewable energy utilization has been receiving attention in the power system industry. The wave-offshore hybrid generation system (HGS, which has a capacity of over 10 MW, was recently developed by adopting several voltage source converters (VSC, while a control method for adopted power conversion systems has not yet been configured in spite of the unique system characteristics of the designated structure. This paper deals with a reactive power assignment method for the developed hybrid system to improve the power transfer efficiency of the entire system. Through the development and application processes for an optimization algorithm utilizing the real-time active power profiles of each generator, a feasibility confirmation of power transmission loss reduction was implemented. To find the practical effect of the proposed control scheme, the real system information regarding the demonstration process was applied from case studies. Also, an evaluation for the loss of the improvement rate was calculated.

  11. An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

    DEFF Research Database (Denmark)

    Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

    2016-01-01

    generation) due to the intermittency. In that case, unbalance in active power generation may occur among the paralleled systems. Additionally, most droop-controlled systems have been assumed to be a single dc-ac inverter with a fixed dc input source. The dc-dc converter as the front-end of a two......-stage photovoltaic (PV) system has not been considered. In this paper, an enhanced droop scheme is thus proposed to address those issues, and the proposed scheme can enable resilient active power sharing in parallel two-stage PV inverter systems. Furthermore, a small-signal analysis for the proposed droop control...

  12. An Investigation of Digital Instrumentation and Control System Failure Modes

    International Nuclear Information System (INIS)

    Korsah, Kofi; Cetiner, Mustafa Sacit; Muhlheim, Michael David; Poore, Willis P. III

    2010-01-01

    A study sponsored by the Nuclear Regulatory Commission study was conducted to investigate digital instrumentation and control (DI and C) systems and module-level failure modes using a number of databases both in the nuclear and non-nuclear industries. The objectives of the study were to obtain relevant operational experience data to identify generic DI and C system failure modes and failure mechanisms, and to obtain generic insights, with the intent of using results to establish a unified framework for categorizing failure modes and mechanisms. Of the seven databases studied, the Equipment Performance Information Exchange database was found to contain the most useful data relevant to the study. Even so, the general lack of quality relative to the objectives of the study did not allow the development of a unified framework for failure modes and mechanisms of nuclear I and C systems. However, an attempt was made to characterize all the failure modes observed (i.e., without regard to the type of I and C equipment under consideration) into common categories. It was found that all the failure modes identified could be characterized as (a) detectable/preventable before failures, (b) age-related failures, (c) random failures, (d) random/sudden failures, or (e) intermittent failures. The percentage of failure modes characterized as (a) was significant, implying that a significant reduction in system failures could be achieved through improved online monitoring, exhaustive testing prior to installation, adequate configuration control or verification and validation, etc.

  13. Online optimal control schemes of inlet steam temperature during startup of steam turbines considering low cycle fatigue

    International Nuclear Information System (INIS)

    Zhang, Hengliang; Xie, Danmei; Yu, Yanzhi; Yu, Liangying

    2016-01-01

    Great thermal stresses and fatigue damages will be developed during the startup of steam turbines, which will threaten the safety of operation. To save energy and improve the flexibility of the power unit, inlet steam temperature of steam turbines should be controlled online in an optimal way. A new method to obtain online optimal control schemes of the inlet steam temperature considering low cycle fatigue is presented in this paper using the Green's Function Method and the Pontryagin's Maximum Principle. New analytical models of temperature and thermal stresses are proposed. For a hot startup, constant material properties are used and the steam temperature history that can maintain maximum Von Mises stress close to the permitted value is proved to be the optimal control scheme. For a cold or warm startup, the optimization thermal stress considering temperature dependent material properties is found to be determinated by material properties and Green's functions, which may not be equal to the maximum permitted value. Application of the proposed method to the cold start-up process of a 600 MW steam turbine is introduced. Compared with the conventional start-up scheduling, the proposed optimal control scheme can shorten the time of startup greatly without exceeding permitted fatigue damage. - Highlights: • Green's Function Method and Pontryagin's Maximum Principle are used to obtain optimal schemes. • Suitable mathematical models and aim of optimal control schemes were presented. • Temperature dependent material properties will affect the design of the optimal schemes greatly. • Application of the proposed method to the cold startup of a 600 MW steam turbine is introduced.

  14. A gallium-arsenide digital phase shifter for clock and control signal distribution in high-speed digital systems

    Science.gov (United States)

    Fouts, Douglas J.

    1992-01-01

    The design, implementation, testing, and applications of a gallium-arsenide digital phase shifter and fan-out buffer are described. The integrated circuit provides a method for adjusting the phase of high-speed clock and control signals in digital systems, without the need for pruning cables, multiplexing between cables of different lengths, delay lines, or similar techniques. The phase of signals distributed with the described chip can be dynamically adjusted in eight different steps of approximately 60 ps per step. The IC also serves as a fan-out buffer and provides 12 in-phase outputs. The chip is useful for distributing high-speed clock and control signals in synchronous digital systems, especially if components are distributed over a large physical area or if there is a large number of components.

  15. Cyber secure systems approach for NPP digital control systems

    International Nuclear Information System (INIS)

    McCreary, T. J.; Hsu, A.

    2006-01-01

    Whether fossil or nuclear power, the chief operations goal is to generate electricity. The heart of most plant operations is the I and C system. With the march towards open architecture, the I and C system is more vulnerable than ever to system security attacks (denial of service, virus attacks and others), thus jeopardizing plant operations. Plant staff must spend large amounts of time and money setting up and monitoring a variety of security strategies to counter the threats and actual attacks to the system. This time and money is a drain on the financial performance of a plant and distracts valuable operations resources from their real goals: product. The pendulum towards complete open architecture may have swung too far. Not all aspects of proprietary hardware and software are necessarily 'bad'. As the aging U.S. fleet of nuclear power plants starts to engage in replacing legacy control systems, and given the on-going (and legitimate) concern about the security of present digital control systems, decisions about how best to approach cyber security are vital to the specification and selection of control system vendors for these upgrades. The authors maintain that utilizing certain resources available in today's digital technology, plant control systems can be configured from the onset to be inherently safe, so that plant staff can concentrate on the operational issues of the plant. The authors postulate the concept of the plant I and C being bounded in a 'Cyber Security Zone' and present a design approach that can alleviate the concern and cost at the plant level of dealing with system security strategies. Present approaches through various IT cyber strategies, commercial software, and even postulated standards from various industry/trade organizations are almost entirely reactive and simply add to cost and complexity. This Cyber Security Zone design demonstrates protection from the four classes of cyber security attacks: 1)Threat from an intruder attempting to

  16. The novel stable control scheme of the light source power in the closed-loop fiber optic gyroscope

    Energy Technology Data Exchange (ETDEWEB)

    Ji Zhongxiao [Graduate University of the Chinese Academy of Sciences, Beijing (China); Ma Caiwen, E-mail: jzx@opt.ac.cn [Xi' an Institute of Optics and Precision Mechanics of the Chinese Academy of Sciences, NO.17 Xinxi Road, New Industrial Park, Xi' an Hi-Tech Industrial Development Zone, Xi' an, Shaanxi (China)

    2011-02-01

    The light source power stability of the Fiber-Optic Gyroscope (FOG) affects directly the scale factor and bias stability of FOG. The typical control scheme of the light source power employs an additional photodetector to detect the output power of the light source. When the fiber loss of FOG varied due to the temperature change, the light power in the additional photodetector did not indicate this change, which decreased the control effect. The spike pulse overlapping on the gyro signal denotes potentially the change of the light power and fiber loss. In the novel scheme, the spike pulse is extracted from the gyro signal, and is transformed into the square wave by the differential circuit. According to the change of the square wave amplitude, FOG adjusts the bias current of the light source to keep the stable light power in the signal photodetector. It is a simple and low-cost scheme without an additional photodetector.

  17. Identification of isomers and control of ionization and dissociation processes using dual-mass-spectrometer scheme and genetic algorithm optimization

    International Nuclear Information System (INIS)

    Chen Zhou; Qiu-Nan Tong; Zhang Cong-Cong; Hu Zhan

    2015-01-01

    Identification of acetone and its two isomers, and the control of their ionization and dissociation processes are performed using a dual-mass-spectrometer scheme. The scheme employs two sets of time of flight mass spectrometers to simultaneously acquire the mass spectra of two different molecules under the irradiation of identically shaped femtosecond laser pulses. The optimal laser pulses are found using closed-loop learning method based on a genetic algorithm. Compared with the mass spectra of the two isomers that are obtained with the transform limited pulse, those obtained under the irradiation of the optimal laser pulse show large differences and the various reaction pathways of the two molecules are selectively controlled. The experimental results demonstrate that the scheme is quite effective and useful in studies of two molecules having common mass peaks, which makes a traditional single mass spectrometer unfeasible. (paper)

  18. A digital control and monitoring system for PWR waste-disposal systems

    International Nuclear Information System (INIS)

    Ueda, Toshiharu; Fuchigami, Kazuyuki; Shimozato, Masao; Takazawa, Kazuo

    1982-01-01

    Mitsubishi Electric has developed a digital control and monitoring system for PWR waste-disposal systems. This novel system has improved operability due to its automated operations and control, and integrated supervisory functions. The system includes other features to improve operability: sequence control by a control computer, direct-digital process control, integrated supervision of operation states by a supervisory computer and a high-speed dataway, and CRT interfacing between the computer and dataway. (author)

  19. 76 FR 62642 - Digital Broadcast Television Redistribution Control; Corrections

    Science.gov (United States)

    2011-10-11

    ... Characteristic,'' (July 6, 2010), as listed below: (i) A/53, Part 1:2007, ``Digital Television System'' (January... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [DA 11-1432] Digital Broadcast Television..., Radio, Television. Accordingly, 47 CFR part 73 is corrected by making the following correcting...

  20. Learning in the Digital Age: Control or Connection?

    Science.gov (United States)

    Van Galen, Jane

    2013-01-01

    In October 2011, 200 state school officers and legislators gathered at a hotel in San Francisco to learn how to "revolutionize" learning by "personalizing" instruction. The occasion was former Florida Gov. Jeb Bush's second annual National Summit on Education Reform. The topic was digital learning. The vision of digitally managed curriculum and…

  1. Modeling and Analysis of Resonance in LCL-Type Grid-Connected Inverters under Different Control Schemes

    Directory of Open Access Journals (Sweden)

    Yanxue Yu

    2017-01-01

    Full Text Available As a basic building block in power systems, the three-phase voltage-source inverter (VSI connects the distributed energy to the grid. For the inductor-capacitor-inductor (LCL-filter three-phase VSI, according to different current sampling position and different reference frame, there mainly exist four control schemes. Different control schemes present different impedance characteristics in their corresponding determined frequency range. To analyze the existing resonance phenomena due to the variation of grid impedances, the sequence impedance models of LCL-type grid-connected three-phase inverters under different control schemes are presented using the harmonic linearization method. The impedance-based stability analysis approach is then applied to compare the relative stability issues due to the impedance differences at some frequencies and to choose the best control scheme and the better controller parameters regulating method for the LCL-type three-phase VSI. The simulation and experiments both validate the resonance analysis results.

  2. Performance Analysis and Optimization of an Adaptive Admission Control Scheme in Cognitive Radio Networks

    Directory of Open Access Journals (Sweden)

    Shunfu Jin

    2013-01-01

    Full Text Available In cognitive radio networks, if all the secondary user (SU packets join the system without any restrictions, the average latency of the SU packets will be greater, especially when the traffic load of the system is higher. For this, we propose an adaptive admission control scheme with a system access probability for the SU packets in this paper. We suppose the system access probability is inversely proportional to the total number of packets in the system and introduce an Adaptive Factor to adjust the system access probability. Accordingly, we build a discrete-time preemptive queueing model with adjustable joining rate. In order to obtain the steady-state distribution of the queueing model exactly, we construct a two-dimensional Markov chain. Moreover, we derive the formulas for the blocking rate, the throughput, and the average latency of the SU packets. Afterwards, we provide numerical results to investigate the influence of the Adaptive Factor on different performance measures. We also give the individually optimal strategy and the socially optimal strategy from the standpoints of the SU packets. Finally, we provide a pricing mechanism to coordinate the two optimal strategies.

  3. VLSI IMPLEMENTATION OF NOVEL ROUND KEYS GENERATION SCHEME FOR CRYPTOGRAPHY APPLICATIONS BY ERROR CONTROL ALGORITHM

    Directory of Open Access Journals (Sweden)

    B. SENTHILKUMAR

    2015-05-01

    Full Text Available A novel implementation of code based cryptography (Cryptocoding technique for multi-layer key distribution scheme is presented. VLSI chip is designed for storing information on generation of round keys. New algorithm is developed for reduced key size with optimal performance. Error Control Algorithm is employed for both generation of round keys and diffusion of non-linearity among them. Two new functions for bit inversion and its reversal are developed for cryptocoding. Probability of retrieving original key from any other round keys is reduced by diffusing nonlinear selective bit inversions on round keys. Randomized selective bit inversions are done on equal length of key bits by Round Constant Feedback Shift Register within the error correction limits of chosen code. Complexity of retrieving the original key from any other round keys is increased by optimal hardware usage. Proposed design is simulated and synthesized using VHDL coding for Spartan3E FPGA and results are shown. Comparative analysis is done between 128 bit Advanced Encryption Standard round keys and proposed round keys for showing security strength of proposed algorithm. This paper concludes that chip based multi-layer key distribution of proposed algorithm is an enhanced solution to the existing threats on cryptography algorithms.

  4. Virtual instrument for controlling and monitoring digitalized power supply in SSRF

    International Nuclear Information System (INIS)

    Tang Junlong; Chen Huanguang; Chinese Academy of Sciences, Beijing; Xu Ruinian; Shen Tianjian; Li Deming

    2006-01-01

    The Shanghai Synchrotron Radiation Facility (SSRF) needs extremely precise power supplies for their various magnets. A digital controller is being developed for the power converters of the SSRF power supply (PS). In the digital controller, a fully digital pulse-width modulator (PWM) directly controls the power unit insulated gate bipolar transistor (IGBT) of the PS. A program in LabVIEW language has been developed to control and monitor the digital PS via serial communication (RS232) from a PC and to modify its parameters as well. In this article, the software design of the virtual instrument for controlling and monitoring digitalized PS and its associated functions are described, and the essential elements of the program graphical main-VI and sub-VI source code are presented and explained. The communication protocol and the structure of the developed system are also included in this article. (authors)

  5. A SUITABLE CONTROL SCHEME FOR THE BINARY MULTIPLIER DATA BANK OF VLSI CAD

    Directory of Open Access Journals (Sweden)

    O. I. Tymoshkin

    2009-09-01

    Full Text Available Problem of elaborating a databank of testable digital elements, units and modules, which are most typical for digital systems, is considered. For this bank an original testable logical circuit of matrix binary multiplier, demanding small amount of hardware for its realization, is proposed.

  6. Concept of Advanced Back-up Control Panel Design of Digital Main Control Room

    International Nuclear Information System (INIS)

    Jiang, Guo Jin; Sun, Yong Bin; Tan, Ke; Zhang, Li Ming; Shi, Ji; Zhang, Xue Gang; Huang, Wei Jun; Mao, Ting; Liu Yanzi

    2011-01-01

    Back-up control panel (BCP) of digital main control room (DMCR) is the backup means for main computerized control means (MCM). This paper focus on technical issues for advanced design of Backup Panel (BCP) for CPR1000 using qualified computer-based video display unit to display plant process indication and alarms. HFE issues also have been considered in the BCP design. Then, mean to fulfill safety target of NPP, best ergonomic effect has been described. At last conclusion on advanced BCP design is provided

  7. Microwave phase-control scheme based on optical beat wave generation and propagation in an optical fiber

    Science.gov (United States)

    Uehara, Tomoyuki; Tsuji, Kenichiro; Mueller, Guido; Tanner, David

    2018-01-01

    A microwave phase-control scheme is proposed and experimentally demonstrated. Two lasers are combined in an optical fiber coupler to generate a beat signal. The beat frequency is tuned by controlling the frequency of one laser. Using the phase shift of the beat waves with different frequencies during the propagation in an optical fiber, the phase of the radio-frequency (RF) signal generated by a photodetector (PD) can be controlled. Using the phase shift during the propagation of beat waves in an optical fiber with different beat frequencies, the phase of the RF signal generated by a PD connected to the fiber can be controlled. A tunable phase shift ranging from 0 deg to 1400 deg is obtained for frequencies from 6 to 10 GHz. This scheme offers the advantages of fast tuning and precise phase control of an RF signal.

  8. A Reconfiguration Scheme for Accommodating Actuator Failures in Multi-Input, Multi-Output Flight Control Systems

    Science.gov (United States)

    Siwakosit, W.; Hess, R. A.; Bacon, Bart (Technical Monitor); Burken, John (Technical Monitor)

    2000-01-01

    A multi-input, multi-output reconfigurable flight control system design utilizing a robust controller and an adaptive filter is presented. The robust control design consists of a reduced-order, linear dynamic inversion controller with an outer-loop compensation matrix derived from Quantitative Feedback Theory (QFT). A principle feature of the scheme is placement of the adaptive filter in series with the QFT compensator thus exploiting the inherent robustness of the nominal flight control system in the presence of plant uncertainties. An example of the scheme is presented in a pilot-in-the-loop computer simulation using a simplified model of the lateral-directional dynamics of the NASA F18 High Angle of Attack Research Vehicle (HARV) that included nonlinear anti-wind up logic and actuator limitations. Prediction of handling qualities and pilot-induced oscillation tendencies in the presence of these nonlinearities is included in the example.

  9. Robust Power Decoupling Control Scheme for DC Side Split Decoupling Capacitor Circuit with Mismatched Capacitance in Single Phase System

    DEFF Research Database (Denmark)

    Yao, Wenli; Loh, Poh Chiang; Tang, Yi

    2016-01-01

    imperfections when storage mismatch occurs, which may break the standard requirement such as IEEE 1547. As a consequence, a robust control scheme is then proposed for half-bridge circuit, which realized power decoupling by generating second order harmonic voltage on the split dc decoupling capacitor instead...

  10. Developing a Tool Point Control Scheme for a Hydraulic Crane Using Interactive Real-time Dynamic Simulation

    DEFF Research Database (Denmark)

    Pedersen, Mikkel Melters; Hansen, Michael Rygaard; Ballebye, Morten

    2010-01-01

    This paper describes the implementation of an interactive real-time dynamic simulation model of a hydraulic crane. The user input to the model is given continuously via joystick and output is presented continuously in a 3D animation. Using this simulation model, a tool point control scheme...

  11. Replacement of the complete control system of the NPP Oskarshamn 1 by digital distributed control system

    International Nuclear Information System (INIS)

    Berger, E.

    1998-01-01

    As part of an ongoing modernization program, the I and C system and the control room of Oskarshamn 1 will be upgraded by ABB using its 'Advant Power' range of digital, programmable process control system. Besides ensuring the higher level of safety that is demanded today, the new equipment provides the plant with an integrated system which will improve operator interaction with the plant and reduce the risk of human error. The newly installed DCS system will serve also as a platform for further improvements of the control room. This paper discusses Oskarshamn 1 exchange of the complete control system of a nuclear power plant, the technical solution and the time schedule. Oskarshamn 1 is the first nuclear power plant in Sweden. It is a boiling water reactor built between 1966 and 1971 by ABB ATOM in Sweden. According to the plant age the control system is relay-based, while instrumentation and analogue control is semiconductor-based. This makes maintenance expensive and even worse, makes extensions nearly impossible. According to the safety standards of the 1960s, there is no separation between safety and non safety control and no seismic qualification. To extend the life of this plant the owner has decided to improve the safety system as well as to replace the reactor protection system, the safety related control and the non safety related control by a state-of-the-art digital distributed control system from ABB. In March 1997, ABB got the order to replace the reactor protection system, the safety control system and to start the replacement of all control systems. The old control room has to be replaced by a new ergonomically design. Together with the exchange of the control system the safety features of the plant and the emergency power supply has to be extended. (author)

  12. Power quality improvement by using STATCOM control scheme in wind energy generation interface to grid

    Science.gov (United States)

    Kirmani, Sheeraz; Kumar, Brijesh

    2018-01-01

    “Electric Power Quality (EPQ) is a term that refers to maintaining the near sinusoidal waveform of power distribution bus voltages and currents at rated magnitude and frequency”. Today customers are more aware of the seriousness that the power quality possesses, this prompt the utilities to assure good quality of power to their customer. The power quality is basically customer centric. Increased focus of utilities toward maintaining reliable power supply by employing power quality improvement tools has reduced the power outages and black out considerably. Good power quality is the characteristic of reliable power supply. Low power factor, harmonic pollution, load imbalance, fast voltage variations are some common parameters which are used to define the power quality. If the power quality issues are not checked i.e. the parameters that define power quality doesn't fall within the predefined standards than it will lead into high electricity bill, high running cost in industries, malfunctioning of equipments, challenges in connecting renewable. Capacitor banks, FACTS devices, harmonic filters, SVC’s (static voltage compensators), STATCOM (Static-Compensator) are the solutions to achieve the power quality. The performance of Wind turbine generators is affected by poor quality power, at the same time these wind power generating plant affects the power quality negatively. This paper presents the STATCOM-BESS (battery energy storage system) system and studies its impact on the power quality in a system which consists of wind turbine generator, non linear load, hysteresis controller for controlling the operation of STATCOM and grid. The model is simulated in the MATLAB/Simulink. This scheme mitigates the power quality issues, improves voltage profile and also reduces harmonic distortion of the waveforms. BESS level out the imbalances caused in real power due to intermittent nature of wind power available due to varying wind speeds.

  13. Digit forces bias sensorimotor transformations underlying control of fingertip position

    Science.gov (United States)

    Shibata, Daisuke; Kappers, Astrid M. L.; Santello, Marco

    2014-01-01

    Humans are able to modulate digit forces as a function of position despite changes in digit placement that might occur from trial to trial or when changing grip type for object manipulation. Although this phenomenon is likely to rely on sensing the position of the digits relative to each other and the object, the underlying mechanisms remain unclear. To address this question, we asked subjects (n = 30) to match perceived vertical distance between the center of pressure (CoP) of the thumb and index finger pads (dy) of the right hand (“reference” hand) using the same hand (“test” hand). The digits of reference hand were passively placed collinearly (dy = 0 mm). Subjects were then asked to exert different combinations of normal and tangential digit forces (Fn and Ftan, respectively) using the reference hand and then match the memorized dy using the test hand. The reference hand exerted Ftan of thumb and index finger in either same or opposite direction. We hypothesized that, when the tangential forces of the digits are produced in opposite directions, matching error (1) would be biased toward the directions of the tangential forces; and (2) would be greater when the remembered relative contact points are matched with negligible digit force production. For the test hand, digit forces were either negligible (0.5–1 N, 0 ± 0.25 N; Experiment 1) or the same as those exerted by the reference hand (Experiment 2).Matching error was biased towards the direction of digit tangential forces: thumb CoP was placed higher than the index finger CoP when thumb and index finger Ftan were directed upward and downward, respectively, and vice versa (p forces. We propose that the expected sensory consequence of motor commands for tangential forces in opposite directions overrides estimation of fingertip position through haptic sensory feedback. PMID:25136304

  14. Application of a dual-resolution voxelization scheme to compressed-sensing (CS)-based iterative reconstruction in digital tomosynthesis (DTS)

    Science.gov (United States)

    Park, S. Y.; Kim, G. A.; Cho, H. S.; Park, C. K.; Lee, D. Y.; Lim, H. W.; Lee, H. W.; Kim, K. S.; Kang, S. Y.; Park, J. E.; Kim, W. S.; Jeon, D. H.; Je, U. K.; Woo, T. H.; Oh, J. E.

    2018-02-01

    In recent digital tomosynthesis (DTS), iterative reconstruction methods are often used owing to the potential to provide multiplanar images of superior image quality to conventional filtered-backprojection (FBP)-based methods. However, they require enormous computational cost in the iterative process, which has still been an obstacle to put them to practical use. In this work, we propose a new DTS reconstruction method incorporated with a dual-resolution voxelization scheme in attempt to overcome these difficulties, in which the voxels outside a small region-of-interest (ROI) containing target diagnosis are binned by 2 × 2 × 2 while the voxels inside the ROI remain unbinned. We considered a compressed-sensing (CS)-based iterative algorithm with a dual-constraint strategy for more accurate DTS reconstruction. We implemented the proposed algorithm and performed a systematic simulation and experiment to demonstrate its viability. Our results indicate that the proposed method seems to be effective for reducing computational cost considerably in iterative DTS reconstruction, keeping the image quality inside the ROI not much degraded. A binning size of 2 × 2 × 2 required only about 31.9% computational memory and about 2.6% reconstruction time, compared to those for no binning case. The reconstruction quality was evaluated in terms of the root-mean-square error (RMSE), the contrast-to-noise ratio (CNR), and the universal-quality index (UQI).

  15. Quality control for some digital fluoroscopy equipment used in Sudan

    International Nuclear Information System (INIS)

    Nayledam, A. I.

    2009-07-01

    The aim of this work was to perform quality control (QC) for six digital fluoroscopy units used for cardiovascular and interventional radiology procedures. Measurement were based on the QC protocol developed in the framework of European Commission (EU) DIMOND111 project. Measurement made included: beam quality (half-value layer, HVL), peak tube voltage (kVp) accuracy, automatic exposure control (Aec) and patient dose in terms of entrance surface air kerma rate plus image intensifier input air kerma rate. Dose measurements were made using Calibrated dose rate meter. Field limitation and source to skin distant measurement in addition to evaluation radiation protection tools for occupation exposure were performed. Image quality was evaluated in terms of spatial resolution and Contrast detail detectability. Patient dose measurements was performed using polymethylmethacrylate (PMMA) patient equivalent phantom whereas image quality was assessed using Haunter Type 53 spatial frequency grating and TO10 contrast detail phantom. The results show that the measured HVL and peak tube voltage were within the recommended limits of 10% in four fluoroscopy units. Entrance surface air kerma rate measured ranged from 6.1 to 250 mGy/min for fluoroscopy units operated in pulsed, continuous and cine mode of operation. These results were obtained using varying thicknesses of PMMA phantom. Most values are in reasonable agreement with internationally established reference levels with exception to one fluoroscopy unit where doses were remarkably high. Field limitation and minimum source to skin distance were well within the recommended limits of 30 cm for all fluoroscopy units. The limiting resolution was ranged from 1.0 to 2.2 Lp /mm for image intensifier field diameters between 7 ad 23 cm. The results of present study can be used as baseline for future quality assurance measurements. (Author)

  16. A Repetitive Control Scheme Aimed at Compensating the 6k + 1 Harmonics for a Three-Phase Hybrid Active Filter

    Directory of Open Access Journals (Sweden)

    Zhaoxu Luo

    2016-09-01

    Full Text Available The traditional repetitive controller has relatively worse stability and poor transient performance because it generates infinite gain at all the integer multiples of the fundamental frequency, and its control action is postponed by one fundamental period (T0. To improve these disadvantages, many repetitive controllers with reduced delay time have been proposed, which can selectively compensate the odd harmonics or 6k ± 1 harmonics with delay time reduced to T0/2 and T0/3, respectively. To further study in this area, this paper proposes an improved repetitive scheme implemented in a stationary reference frame, which only compensates the 6k + 1 harmonics (e.g., −5, +7, −11, +13 in three-phase systems and reduces the time delay to T0/6. Thus compared with the earlier reduced delay time repetitive controllers, the robustness and transient performance is further improved, the waste of control effort is reduced, and the possibility of amplifying and even injecting any harmonic noises into the system is avoided to a great extent. Moreover, the proposed repetitive scheme is used in the control of a three-phase hybrid active power filter. The experimental results validate the effectiveness of the proposed repetitive control scheme.

  17. Digital instrumentation and control - how not to do it

    International Nuclear Information System (INIS)

    Anon.

    1997-01-01

    A report entitled ''Digital I and C systems in nuclear power plants: safety and reliability issues'' has been produced by the US National Research Council at the behest of the Nuclear Regulatory Commission (NRC). Phase 1 of the reported study identified eight key issues: software quality assurance; common-mode software failure potential; systems aspects of digital I and C technology; human factors and human-machine interfaces; safety and reliability assessment methods; dedication of commercial off-the-shelf hardware and software; a case-by-case licensing process; adequacy of technical infrastructure. These were addressed by considering the impact of digital I and C systems against a set of standard regulatory approaches to assessing and ensuring safety. Phase 2 dealt with the criteria for reviewing and approving digital I and C technology, the characterisation and evaluation of alternative approaches to licensing the technology, and guidelines for the NRC to license and regulate it. (UK)

  18. A Repetitive Control Scheme Aimed at Compensating the 6k + 1 Harmonics for a Three-Phase Hybrid Active Filter

    DEFF Research Database (Denmark)

    Luo, Zhaoxu; Su, Mei; Yang, Jian

    2016-01-01

    these disadvantages, many repetitive controllers with reduced delay time have been proposed, which can selectively compensate the odd harmonics or 6k±1 harmonics with delay time reduced to T0/2 and T0/3,repectively. To further study in this area, this paper proposes an improved repetitive scheme implemented...... in stationary reference frame, which only compensates the 6k+1 harmonics (e.g. -5, +7, -11, +13) in three-phase systems and reduces the time delay to T0/6 . So compared with the earlier reduced delay time repetitive controllers, the robustness and transient performance is further improved, the waste of control...... effort is reduced, and the possibility of amplifying and even injecting any harmonic noises into system is avoided to the greatest extent. Moreover, the proposed repetitive scheme is used in the control of a three-phase hybrid active power filter. The experimental results validate the effectiveness...

  19. Design for the human-machine interface of a digitalized reactor control-room

    International Nuclear Information System (INIS)

    Qu Ronghong; Zhang Liangju; Li Duo; Yu Hui

    2005-01-01

    Digitalized technology is implemented in the instrumentation and control system of an in-construction research reactor, which advances information display in both contents and styles in a nuclear reactor control-room, and greatly improves human-machine interface. In the design for a digitalized nuclear reactor control-room there are a series of new problems and technologies should be considered seriously. This paper mainly introduces the design for the digitalized control-room of the research nuclear reactor and covered topics include design principle of human-machine interface, organization and classification of interface graphics, technologies and principles based on human factors engineering and implemented in the graphics design. (authors)

  20. A study of temperature sensor location based on fractal analysis for cascade control schemes in tubular reactors

    DEFF Research Database (Denmark)

    Eduardo Ramirez-Castelan, Carlos; Moguel-Castañeda, Jazael; Puebla, Hector

    2016-01-01

    Temperature sensor location for cascade control schemes in tubular reactors is still an open research problem. Several studies have pointed out that most temperature sensitive zones along the length of the reactor are suitable to this end. In this work, we have studied the problem of sensor...... location in a cascade control configuration using fractal analysis of time series obtained by random forcing of the jacket rector. A benchmark dispersion axial model displaying different temperature profiles is used to illustrate our findings....

  1. The effect of targeting scheme on tidal volume delivery during volume control mechanical ventilation.

    Science.gov (United States)

    Volsko, Teresa A; Hoffman, Justin; Conger, Alecia; Chatburn, Robert L

    2012-08-01

    Technological advances have increased ventilator mode complexity and risk of operator error. To compare differences in volume control (VC) ventilation with set-point and dual targeting. Two hypotheses were tested: tidal volume (V(T)) delivery is different with VC using set-point versus dual targeting during active versus passive breathing; VC with dual targeting delivers V(T) similar to pressure support ventilation (PS) with active breathing. The Ingmar Medical ASL 5000 lung model simulated pulmonary mechanics of an adult patient with ARDS during active and passive ventilation. Resistance was standardized at 10 cm H(2)O/L/s and compliance at 32 mL/cm H(2)O. Active breathing was simulated by setting the frequency (f) = 26 breaths/min, and adjusting the muscle pressure (P(mus)) to produce a V(T) of 384 mL. VC was initiated with the Puritan Bennett 840 (set-point targeting) and the Servo-i (dual targeting) at V(T) = 430 mL, mandatory f = 15 breaths/min, and PEEP = 10 cm H(2)O. During PS, cycle threshold was set to 30% and peak inspiratory pressure adjusted to produce a V(T) similar to that delivered during VC. Expiratory V(T) was collected on 10 consecutive breaths during active and passive breathing with VC and PS. Mean V(T) differences (active vs passive model) were compared using analysis of variance. Statistical significance was established at P targeting schemes: VC set-point = 37.3 ± 3.5 mL, VC-dual = 77.1 ± 3.3 mL, and PS = 406.1 ± 1.5 mL (P targeting during VC allows increased V(T), compared to set-point, but not as much as PS.

  2. Continuous quality control of the blood sampling procedure using a structured observation scheme.

    Science.gov (United States)

    Seemann, Tine Lindberg; Nybo, Mads

    2016-10-15

    An observational study was conducted using a structured observation scheme to assess compliance with the local phlebotomy guideline, to identify necessary focus items, and to investigate whether adherence to the phlebotomy guideline improved. The questionnaire from the EFLM Working Group for the Preanalytical Phase was adapted to local procedures. A pilot study of three months duration was conducted. Based on this, corrective actions were implemented and a follow-up study was conducted. All phlebotomists at the Department of Clinical Biochemistry and Pharmacology were observed. Three blood collections by each phlebotomist were observed at each session conducted at the phlebotomy ward and the hospital wards, respectively. Error frequencies were calculated for the phlebotomy ward and the hospital wards and for the two study phases. A total of 126 blood drawings by 39 phlebotomists were observed in the pilot study, while 84 blood drawings by 34 phlebotomists were observed in the follow-up study. In the pilot study, the three major error items were hand hygiene (42% error), mixing of samples (22%), and order of draw (21%). Minor significant differences were found between the two settings. After focus on the major aspects, the follow-up study showed significant improvement for all three items at both settings (P < 0.01, P < 0.01, and P = 0.01, respectively). Continuous quality control of the phlebotomy procedure revealed a number of items not conducted in compliance with the local phlebotomy guideline. It supported significant improvements in the adherence to the recommended phlebotomy procedures and facilitated documentation of the phlebotomy quality.

  3. Design and Implement a Digital H∞ Robust Controller for a MW-Class PMSG-Based Grid-Interactive Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Tomonobu Senjyu

    2013-04-01

    Full Text Available A digital H∞ controller for a permanent magnet synchronous generator (PMSG based wind energy conversion system (WECS is presented. Wind energy is an uncertain fluctuating resource which requires a tight control management. So, it is still an exigent task for the control design engineers. The conventional proportional-integral (PI control is not ideal during high turbulence wind velocities, and the nonlinear behavior of the power converters. These are raising interest towards the robust control concepts. The robust design is to find a controller, for a given system, such that the closed-loop system becomes robust that assurance high-integrity and fault tolerant control system, robust H∞ control theory has befallen a standard design method of choice over the past two decades in industrial control applications. The robust H∞ control theory is also gaining eminence in the WECS. Due to the implementation complexity for the continuous H∞ controller, and availability of the high speedy micro-controllers, the design of a sample-data or a digital H∞ controller is very important for the realistic implementation. But there isn’t a single research to evaluate the performance of the digital H∞ controller for the WECS. In this paper, the proposed digital H∞ controller schemes comprise for the both generator and grid interactive power converters, and the control performances are compared with the conventional PI controller and the fuzzy controller. Simulation results confirm the efficacy of the proposed method Energies 2013, 6 2085 which are ensured the WECS stabilities, mitigate shaft stress, and improving the DC-link voltage and output power qualities.

  4. Design and Implement a Digital H{sub {infinity}}Robust Controller for a MW-Class PMSG-Based Grid-Interactive Wind Energy Conversion System

    Energy Technology Data Exchange (ETDEWEB)

    Howlander, Abdul Motin [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Urasaki, Naomitsu [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Yona, Atsushi [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Senjyu, Tomonobu [Faculty of Engineering, Univ. of the Ryukyus, Okinawa (Japan); Saber, Ahmed Yousuf [Operation Technology, Irvine, CA (United States)

    2013-04-15

    A digital H{sub {infinity}}controller for a permanent magnet synchronous generator (PMSG) based wind energy conversion system (WECS) is presented. Wind energy is an uncertain fluctuating resource which requires a tight control management. So, it is still an exigent task for the control design engineers. The conventional proportional-integral (PI) control is not ideal during high turbulence wind velocities, and the nonlinear behavior of the power converters. These are raising interest towards the robust control concepts. The robust design is to find a controller, for a given system, such that the closed-loop system becomes robust that assurance high-integrity and fault tolerant control system, robust H{sub {infinity}}control theory has befallen a standard design method of choice over the past two decades in industrial control applications. The robust H{sub {infinity}}control theory is also gaining eminence in the WECS. Due to the implementation complexity for the continuous H{sub {infinity}}controller, and availability of the high speedy micro-controllers, the design of a sample-data or a digital H{sub {infinity}}controller is very important for the realistic implementation. But there isn’t a single research to evaluate the performance of the digital H{sub {infinity}}controller for the WECS. In this paper, the proposed digital H{sub {infinity}}controller schemes comprise for the both generator and grid interactive power converters, and the control performances are compared with the conventional PI controller and the fuzzy controller. Simulation results confirm the efficacy of the proposed method Energies 2013, 6 2085 which are ensured the WECS stabilities, mitigate shaft stress, and improving the DC-link voltage and output power qualities.

  5. Wavelet-based Encoding Scheme for Controlling Size of Compressed ECG Segments in Telecardiology Systems.

    Science.gov (United States)

    Al-Busaidi, Asiya M; Khriji, Lazhar; Touati, Farid; Rasid, Mohd Fadlee; Mnaouer, Adel Ben

    2017-09-12

    One of the major issues in time-critical medical applications using wireless technology is the size of the payload packet, which is generally designed to be very small to improve the transmission process. Using small packets to transmit continuous ECG data is still costly. Thus, data compression is commonly used to reduce the huge amount of ECG data transmitted through telecardiology devices. In this paper, a new ECG compression scheme is introduced to ensure that the compressed ECG segments fit into the available limited payload packets, while maintaining a fixed CR to preserve the diagnostic information. The scheme automatically divides the ECG block into segments, while maintaining other compression parameters fixed. This scheme adopts discrete wavelet transform (DWT) method to decompose the ECG data, bit-field preserving (BFP) method to preserve the quality of the DWT coefficients, and a modified running-length encoding (RLE) scheme to encode the coefficients. The proposed dynamic compression scheme showed promising results with a percentage packet reduction (PR) of about 85.39% at low percentage root-mean square difference (PRD) values, less than 1%. ECG records from MIT-BIH Arrhythmia Database were used to test the proposed method. The simulation results showed promising performance that satisfies the needs of portable telecardiology systems, like the limited payload size and low power consumption.

  6. Design of active controls for the NASA F-8 digital fly-by-wire airplane

    Science.gov (United States)

    Gera, J.

    1976-01-01

    The design of a set of control laws for the NASA F-8 digital fly by wire research airplane is described. These control laws implement several active controls functions: maneuver load control, ride smoothing and departure boundary limiting. The criteria and methods which were used in the design of the control laws are also included. Results of linear analyses and nonlinear simulation are summarized.

  7. Digital control of laser modes with an intra-cavity spatial light modulator

    CSIR Research Space (South Africa)

    Ngcobo, S

    2014-02-01

    Full Text Available In this paper we outline a simple laser cavity which produces customised on-demand digitally controlled laser modes by replacing the end-mirror of the cavity with an electrically addressed reflective phase-only spatial light modulator as a digital...

  8. Experimental direct digital control of the power plant A1 reactor based on a modern control theory approach

    International Nuclear Information System (INIS)

    Karpeta, C.

    1979-01-01

    The objective of the project was to accumulate technical experience with application of modern control theory in nuclear power by carrying out a case study of an experimental direct digital control at the A1 reactor about its nominal steady state. The research has proved that slightly modified method of solution of the linear stochastic regulator problem can be successfully applied in design of digital control system of nuclear power reactors

  9. Development of Reactor Protection System (RPS) in Reactor Digital Instrumentation and Control System (ReDICS)

    International Nuclear Information System (INIS)

    Mohd Khairulezwan Abdul Manan; Mohd Sabri Minhat; Ridzuan Abdul Mutalib

    2013-01-01

    RTP Research Reactor are in the process upgraded from analogue control console system to a digital control console system . Upgrade process requires a statistical study to improve safety during reactor operation. RPS was developed to meet the needs of operational safety and at the same time comply with the guidelines set by the IAEA. RPS is in analog and hardware with industry standard interfaced with digital DAC (Data Acquisition and Control) and OWS (Operator Work Station). (author)

  10. Active defense scheme against DDoS based on mobile agent and network control in network confrontation

    Science.gov (United States)

    Luo, Rong; Li, Junshan; Ye, Xia; Wang, Rui

    2013-03-01

    In order to effective defend DDoS attacks in network confrontation, an active defense scheme against DDoS is built based on Mobile Agent and network control. A distributed collaborative active defense model is constructed by using mobile agent technology and encapsulating a variety of DDoS defense techniques. Meanwhile the network control theory is applied to establish a network confrontation's control model for DDoS to control the active defense process. It provides a new idea to solve the DDoS problem.

  11. A Multiagent System-Based Protection and Control Scheme for Distribution System With Distributed-Generation Integration

    DEFF Research Database (Denmark)

    Liu, Z.; Su, Chi; Hoidalen, Hans

    2017-01-01

    In this paper, a multi agent system (MAS) based protection and control scheme is proposed to deal with diverse operation conditions in distribution system due to distributed generation (DG) integration. Based on cooperation between DG controller and relays, an adaptive protection and control...... algorithm is designed on converter based wind turbine DG to limit the influence of infeed fault current. With the consideration of DG control modes, an adaptive relay setting strategy is developed to help protective relays adapt suitable settings to different operation conditions caused by the variations...

  12. How Green is your scheme? Greenhouse gas control the Australian way

    International Nuclear Information System (INIS)

    Lo, Alex Y.; Spash, Clive L.

    2012-01-01

    Australia managed to pass a national carbon pricing scheme into legislation in November 2011, which has come into effect from July 2012. The scheme includes elements of a CO 2 -equivalent tax as a short prelude to emission trading. Several fundamental problems remain unaddressed, including: the continuing rise of emissions, the scale of growth and economic activity, the promotion of emission trading, subsidies to polluters, the hidden promotion of banking and finance sectors. The new policy appears primarily targeted at job creation and business as usual. We argue that the prospects for any meaningful reduction in emission levels are extremely unlikely.

  13. Digitally-controlled PC-interfaced Boost Converter for Educational Purposes

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael A. E.

    2004-01-01

    This paper describes implementation of a simple digital PID control algorithm for a boost converter using a cheap fixed-point 8-bit microcontroller. Serial communication to a PC server program is established for easier downloading of compensator parameters and current and voltage waveform...... acquisition. At the end, client program is presented which uses TCP/IP connection for operating the digitally controlled boost converter over Internet. The aim of this cheap and flexible PC-interfaced boost converter bench is predominantly educational, to allow students to synthesize different digital...... controllers and compare their performance....

  14. Non-linear hybrid control oriented modelling of a digital displacement machine

    DEFF Research Database (Denmark)

    Pedersen, Niels Henrik; Johansen, Per; Andersen, Torben O.

    2017-01-01

    Proper feedback control of digital fluid power machines (Pressure, flow, torque or speed control) requires a control oriented model, from where the system dynamics can be analyzed, stability can be proven and design criteria can be specified. The development of control oriented models for hydraulic...... Digital Displacement Machines (DDM) is complicated due to non-smooth machine behavior, where the dynamics comprises both analog, digital and non-linear elements. For a full stroke operated DDM the power throughput is altered in discrete levels based on the ratio of activated pressure chambers....... In this paper, a control oriented hybrid model is established, which combines the continuous non-linear pressure chamber dynamics and the discrete shaft position dependent activation of the pressure chambers. The hybrid machine model is further extended to describe the dynamics of a Digital Fluid Power...

  15. Derivation and Analysis of a Low-Cost, High-performance Analogue BPCM Control Scheme for Class-D Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael A. E.

    2005-01-01

    This paper presents a low-cost analogue control scheme for class-D audio power amplifiers. The scheme is based around bandpass current-mode (BPCM) control, and provides ample stability margins and low distortion over a wide range of operating conditions. Implementation is very simple and does...

  16. Developing Efficient Coordination Schemes to Control Over-Pumping in the Heihe River Basin, China

    Science.gov (United States)

    Pedrazzini, G.

    2015-12-01

    Many wicked water resources problems are approached in a social planner perspective. This not always matches the real institutional and policy-making context, where, rather, multiple decision-makers (DMs) can act independently, or weakly cooperate, ultimately producing system-wide inefficient trade-offs. The idea in this work is to adopt a more realistic approach, where the multi-DMs nature of the problem is preserved and the uncoordinated DMs are driven, thorough coordination mechanisms, towards a more system-wide efficient solution. An agent-based modelling framework linked to a surface and groundwater model is used to design these coordination mechanisms as constraints to the independent agents (i.e., DMs) behaviour. In the Heihe Basin the ongoing introduction of smart meter IC-card systems on farmers' pumping wells will soon allow monitoring and control of abstractions with the goal of preventing further depletion of the resource. The major interest of policy makers in the region concerns the development of new and the improvement of existing legislation on pricing schemes and/or groundwater quotas. The model outcome where agents act rationally but selfishly is compared to the optimal solution at system-level assuming perfect coordination and cooperation. The optimal solutions with respect to the given utility functions are computed using nonlinear optimization with a rolling out time horizon. The Pareto-Frontier is synthesized through an exhaustive sampling of the weight coefficient space and related to the current and to the historical management of the last 4 decades. The best parameter values for the proposed coordination mechanisms are determined and the alternatives are compared with respect to their efficiency and acceptability. Preliminary results suggest that a regulatory tax on groundwater of about a factor 10 of the current resource fee is required to increase the elasticity of the groundwater demand curve such that reducing consumption becomes

  17. Genetic algorithm-based precision tuning of digital P-I-D controller ...

    African Journals Online (AJOL)

    Tuning of the PID controller is often done by trial and error which is tedious, · time consuming and relatively inefficient. A more reliable and etricient approach of tuning the PID controller using genetic algorithm is presented. The scope of this work is limited to obtaining control parameters of a digital PID controller for a ...

  18. Optimal Priority-based Call Admission Control Scheme For QoS Provisioning in Heterogeneous Wireless Networks

    OpenAIRE

    Wen Chen; Jinming Yu; Feng Pan

    2011-01-01

    Next generation wireless networks will support a diverse set of access technologies. And the demanding breed of multimedia applications will even more considerably require Quality of Service (QoS) support. This paper proposes an optimal prority-based Call Admission Control (CAC) scheme in heterogeneous wireless networks, i.e., the generalized semi-Markov Decision Process based CAC (GCAC). Considering the limitations of the traditional Markov decision process for optimal CAC policy, we charact...

  19. Red Zones: Improving the Enemy Ground Force Situation Display in Digital Battle Command and Control Systems

    National Research Council Canada - National Science Library

    Ceralde, Ray M

    2005-01-01

    ... (the blue picture). This paper argues that the projection of enemy vehicle locations and activity through spatial analysis tools will improve the enemy ground situation display in digital battle command and control systems...

  20. Digital acquisition and wavelength control of seed laser for space-based Lidar applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposes to establish the feasibility of using a space qualifiable Field Programmable Gate Array (FPGA) based digital controller to autonomously...

  1. Control system of digital x-ray systems by quality parameters

    International Nuclear Information System (INIS)

    Balashov, S.V.; Kovalenko, Yu.N.

    2013-01-01

    The paper proposed a control system of X-ray digital equipment on quality indicators. Two basic parameters were determined: image quality and patients' radiation load. A method for monitoring these indicators is proposed. The criterion of equipment suitability is to obtain control digital X-ray images of diagnostically acceptable quality at a fixed low entrance dose in the plane of the digital detector. It is shown that the control system of X-ray digital equipment based on indicators of quality is the most appropriate in situations of deficit of financial resources, since minimizing the costs for the purchase and running of control systems, does not require highly skilled technical personnel, and reduces the duration of the equipment inspection. (authors)

  2. Digital control analysis and design of a field-sensed magnetic suspension system.

    Science.gov (United States)

    Li, Jen-Hsing; Chiou, Juing-Shian

    2015-03-13

    Magnetic suspension systems are mechatronic systems and crucial in several engineering applications, such as the levitation of high-speed trains, frictionless bearings, and wind tunnels. Magnetic suspension systems are nonlinear and unstable systems; therefore, they are suitable educational benchmarks for testing various modeling and control methods. This paper presents the digital modeling and control of magnetic suspension systems. First, the magnetic suspension system is stabilized using a digital proportional-derivative controller. Subsequently, the digital model is identified using recursive algorithms. Finally, a digital mixed linear quadratic regulator (LQR)/H∞ control is adopted to stabilize the magnetic suspension system robustly. Simulation examples and a real-world example are provided to demonstrate the practicality of the study results. In this study, a digital magnetic suspension system model was developed and reviewed. In addition, equivalent state and output feedback controls for magnetic suspension systems were developed. Using this method, the controller design for magnetic suspension systems was simplified, which is the novel contribution of this study. In addition, this paper proposes a complete digital controller design procedure for magnetic suspension systems.

  3. An Optimal Integrated Control Scheme for Permanent Magnet Synchronous Generator-Based Wind Turbines under Asymmetrical Grid Fault Conditions

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-04-01

    Full Text Available In recent years, the increasing penetration level of wind energy into power systems has brought new issues and challenges. One of the main concerns is the issue of dynamic response capability during outer disturbance conditions, especially the fault-tolerance capability during asymmetrical faults. In order to improve the fault-tolerance and dynamic response capability under asymmetrical grid fault conditions, an optimal integrated control scheme for the grid-side voltage-source converter (VSC of direct-driven permanent magnet synchronous generator (PMSG-based wind turbine systems is proposed in this paper. The optimal control strategy includes a main controller and an additional controller. In the main controller, a double-loop controller based on differential flatness-based theory is designed for grid-side VSC. Two parts are involved in the design process of the flatness-based controller: the reference trajectories generation of flatness output and the implementation of the controller. In the additional control aspect, an auxiliary second harmonic compensation control loop based on an improved calculation method for grid-side instantaneous transmission power is designed by the quasi proportional resonant (Quasi-PR control principle, which is able to simultaneously restrain the second harmonic components in active power and reactive power injected into the grid without the respective calculation for current control references. Moreover, to reduce the DC-link overvoltage during grid faults, the mathematical model of DC-link voltage is analyzed and a feedforward modified control factor is added to the traditional DC voltage control loop in grid-side VSC. The effectiveness of the optimal control scheme is verified in PSCAD/EMTDC simulation software.

  4. Experimental investigation of a control scheme for a tuned resonant sideband extraction interferometer for next-generation gravitational-wave detectors

    International Nuclear Information System (INIS)

    Kawazoe, F; Sugamoto, A; Sato, S; Leonhardt, V; Yamazaki, T; Fukushima, M; Kawamura, S; Miyakawa, O; Morioka, T; Nishizawa, A

    2008-01-01

    LCGT plans to use tuned RSE as the optical configuration for its interferometer. A tuned RSE interferometer has five degrees of freedom that need to be controlled in order to operate a gravitational-wave detector, although it is expected to be very challenging because of the complexity of its optical configuration. A new control scheme for a tuned RSE interferometer has been developed and tested with a prototype interferometer to demonstrate successful control of the tuned RSE interferometer. The whole RSE interferometer was successfully locked with the control scheme. Here the control scheme and the current status of the experiment are presented

  5. Study of Direct Torque Controlled 3-phase SCIM with Two and Three-level Inverters using ST-DTC and FR-DTC scheme

    Directory of Open Access Journals (Sweden)

    P. R. Tripathy

    2015-02-01

    Full Text Available DTC control strategy helps to obtain fast and smooth control in 3–phase induction motors. It does not depend upon the machine parameters and transformation of reference frames. Various control strategies on the Direct Torque Control (DTC scheme have been carried out in the present study. The suggested scheme is meant for designing the low cost control circuit for DTC implementation on 3-phase SCIM. Three schemes with two types of inverters have been simulated in MATLAB (Simulink environment and the THD ratio in each case has been studied along with Fast Fourier Transform (FFT tools to compare the advantages.

  6. An Adaptive Fuzzy Control Scheme for Dyebath pH in Exhaust Dyeing

    African Journals Online (AJOL)

    Nafiisah

    . Analog to. Digital. Converter. pH. Transmitter. Dyebath. Acid. Tank. Alkali. Tank ... The flow rate of the acid and alkali dosing pumps are preset to QA and QB litres/s, ... pH change due to acid-base reaction (Astrom and Wittenmark, 1995). It is.

  7. Economic and technical analysis of electric power substations` control and protection digital systems; Analise tecnico-economica de sistemas digitais de protecao e controle de subestacoes

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Nelson Branco; Wochler, William Silveira [Siemens S.A., Sao Paulo, SP (Brazil)

    1995-12-31

    This work talks about the entrance of digital technology, in protection and control digital systems for electric power substations, in the Brazilian market. It makes a comparative evaluation between digital and conventional systems. Finally, the authors conclude that the digital systems present a better cost benefit rate considering not only financial but also functional aspects 4 refs., 1 fig.

  8. Digital control of high-frequency switched-mode power converters

    CERN Document Server

    Corradini, Luca; Mattavelli, Paolo; Zane, Regan

    This book is focused on the fundamental aspects of analysis, modeling and design of digital control loops around high-frequency switched-mode power converters in a systematic and rigorous manner Comprehensive treatment of digital control theory for power converters Verilog and VHDL sample codes are provided Enables readers to successfully analyze, model, design, and implement voltage, current, or multi-loop digital feedback loops around switched-mode power converters Practical examples are used throughout the book to illustrate applications of the techniques developed Matlab examples are also

  9. Digital low level rf control system with four different intermediate frequencies for the International Linear Collider

    Science.gov (United States)

    Wibowo, Sigit Basuki; Matsumoto, Toshihiro; Michizono, Shinichiro; Miura, Takako; Qiu, Feng; Liu, Na

    2017-09-01

    A field programmable gate array-based digital low level rf (LLRF) control system will be used in the International Linear Collider (ILC) in order to satisfy the rf stability requirements. The digital LLRF control system with four different intermediate frequencies has been developed to decrease the required number of analog-to-digital converters in this system. The proof of concept of this technique was demonstrated at the Superconducting RF Test Facility in the High Energy Accelerator Research Organization, Japan. The amplitude and phase stability has fulfilled the ILC requirements.

  10. Apollo experience report: Guidance and control systems - Digital autopilot design development

    Science.gov (United States)

    Peters, W. H.; Cox, K. J.

    1973-01-01

    The development of the Apollo digital autopilots (the primary attitude control systems that were used for all phases of the lunar landing mission) is summarized. This report includes design requirements, design constraints, and design philosophy. The development-process functions and the essential information flow paths are identified. Specific problem areas that existed during the development are included. A discussion is also presented on the benefits inherent in mechanizing attitude-controller logic and dynamic compensation in a digital computer.

  11. The test and control system for high performance digital power supplies of SSRF

    International Nuclear Information System (INIS)

    Tang Junlong; Li Deming; Shen Tianjian

    2009-01-01

    A test and control system was designed to evaluate performance of the digital power supplies for SSRF. The software of serial communication (RS-232) and Ethernet interface was developed with Lab VIEW. The system can perform functions of instrument and power supply control, data acquisition and display, and store data for 24 h. LAN users can access the system and acquire data conveniently. The data are stored in Excel for analysis and establishment of database of digital PS in the future. (authors)

  12. An advanced teaching scheme for integrating problem-based learning in control education

    Science.gov (United States)

    Juuso, Esko K.

    2018-03-01

    Engineering education needs to provide both theoretical knowledge and problem-solving skills. Many topics can be presented in lectures and computer exercises are good tools in teaching the skills. Learning by doing is combined with lectures to provide additional material and perspectives. The teaching scheme includes lectures, computer exercises, case studies, seminars and reports organized as a problem-based learning process. In the gradually refining learning material, each teaching method has its own role. The scheme, which has been used in teaching two 4th year courses, is beneficial for overall learning progress, especially in bilingual courses. The students become familiar with new perspectives and are ready to use the course material in application projects.

  13. New optical scheme of the intensity control for a remote gas analyzer

    Science.gov (United States)

    Shabrov, Denis V.; Gorobets, Vadim A.; Puchkouski, Ilya N.; Kuntsevich, Boris F.

    2017-10-01

    The new scheme of the reference channel of a remote gas analyzer has been offered and realized. The use of additional reflective elements with the low reflection factor allows to receive full interception of laser radiation and to provide a linear operating mode of a photodetector even for the strongest laser lines. At the measurement of a concentration of air pollutions on a differential method the weak dependence of reflection factors for used reflecting plates from wavelength can be easy to take into account by adding corresponding factors in the formula for calculations of air pollution concentrations. The application of the new optical scheme of the reference channel for the gas analyzer and the addition new correcting temperature constants in the calculations has allowed carrying out correct measurements of air pollutants with the high accuracy.

  14. Event-driven control of a speed varying digital displacement machine

    DEFF Research Database (Denmark)

    Pedersen, Niels Henrik; Johansen, Per; Andersen, Torben O.

    2017-01-01

    The design and analysis of feedback controllers for digital displacement machines requires a control oriented model. The displacement throughput of a full stroke operated machine is altered on a stroke-by-stroke basis at fixed rotation angles. In the case of a fixed speed operation, it may...... be treated as a Discrete Linear Time Invariant control problem with synchronous sampling rate. To make synchronous linear control theory applicable for a variable speed digital displacement machine, a method based on event-driven control is presented. Using this method, the time domain differential equations...... are converted into the spatial (position) domain to obtain a constant sampling rate and thus allowing for use of classical control theory. The method is applied to a down scaled digital fluid power motor, where the motor speed is controlled at varying references under varying pressure and load torque conditions...

  15. Continuous quality control of the blood sampling procedure using a structured observation scheme

    OpenAIRE

    Lindberg Seemann, Tine; Nybo, Mads

    2016-01-01

    INTRODUCTION: An observational study was conducted using a structured observation scheme to assess compliance with the local phlebotomy guideline, to identify necessary focus items, and to investigate whether adherence to the phlebotomy guideline improved.MATERIALS AND METHODS: The questionnaire from the EFLM Working Group for the Preanalytical Phase was adapted to local procedures. A pilot study of three months duration was conducted. Based on this, corrective actions were implemented and a ...

  16. Integration of analog and digital instrumentation and control systems in hybrid control rooms

    International Nuclear Information System (INIS)

    2010-01-01

    he IAEA's activities in the area of nuclear power plant operating performance and life cycle management are aimed at increasing Member State capabilities in utilizing good engineering and management practices as developed and transferred by the IAEA. In particular, the IAEA supports the improvement of nuclear power plant performance, plant life management, training, power uprating, operational license renewal, and the modernization of instrumentation and control (I and C) systems of plants. The issue of the integration of analog and digital I and C systems in hybrid control rooms was suggested by the IAEA Technical Working Group on Nuclear Power Plant Control and Instrumentation (TWG-NPPCI) at its meetings in 2003 and 2005. The subject was then approved by the IAEA and included in its work programmes for 2006-2009. The purpose of this report is to help nuclear utilities in planning control room and other human system interface (HSI) changes, making appropriate use of modern technologies. These technologies would aid in managing ageing and obsolescence, and facilitate improvements in plant performance and safety. This report covers a broad spectrum of potential changes to the control room ranging from the replacement of a few obsolete components with newer digital devices to a fully computerized control room. New digital technologies offer significant opportunities to improve access to and presentation of information to the user, e.g. operators, maintenance staff and management. However, this technology should be used prudently. In some cases, modernization is undertaken to resolve ageing and obsolescence or to meet regulatory requirements for license renewal. The integration of new technologies during main control room (MCR) modernizations should be performed cautiously and all affected aspects of plant maintenance, and operation should be carefully considered, paying particular attention to the human factors elements of these aspects. This report describes a

  17. A distributed model predictive control based load frequency control scheme for multi-area interconnected power system using discrete-time Laguerre functions.

    Science.gov (United States)

    Zheng, Yang; Zhou, Jianzhong; Xu, Yanhe; Zhang, Yuncheng; Qian, Zhongdong

    2017-05-01

    This paper proposes a distributed model predictive control based load frequency control (MPC-LFC) scheme to improve control performances in the frequency regulation of power system. In order to reduce the computational burden in the rolling optimization with a sufficiently large prediction horizon, the orthonormal Laguerre functions are utilized to approximate the predicted control trajectory. The closed-loop stability of the proposed MPC scheme is achieved by adding a terminal equality constraint to the online quadratic optimization and taking the cost function as the Lyapunov function. Furthermore, the treatments of some typical constraints in load frequency control have been studied based on the specific Laguerre-based formulations. Simulations have been conducted in two different interconnected power systems to validate the effectiveness of the proposed distributed MPC-LFC as well as its superiority over the comparative methods. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  18. A satellite digital controller or 'play that PID tune again, Sam'. [Position, Integral, Derivative feedback control algorithm for design strategy

    Science.gov (United States)

    Seltzer, S. M.

    1976-01-01

    The problem discussed is to design a digital controller for a typical satellite. The controlled plant is considered to be a rigid body acting in a plane. The controller is assumed to be a digital computer which, when combined with the proposed control algorithm, can be represented as a sampled-data system. The objective is to present a design strategy and technique for selecting numerical values for the control gains (assuming position, integral, and derivative feedback) and the sample rate. The technique is based on the parameter plane method and requires that the system be amenable to z-transform analysis.

  19. Control Scheme of River-lake System from the View of Ecological Sponge Basin aiming at Sponge City Construction

    Science.gov (United States)

    Ding, X.; Liu, J.; Yang, Z.

    2017-12-01

    China is in the rapid advance of urbanization, and is promoting the Sponge City Construction (SCC) with the characteristics of natural accumulation, natural infiltration and natural purification. The Chinese government selected 16 and 14 cities as pilot cities in 2015 and 2016 respectively to carry out SCC taking Low Impact Development (LID) as the concept. However, in 2015 and 2016, water-logging occurred in 10 cities and 9 cities respectively during the pilot cities. Therefore, relying solely on LID can not solve the problem of urban flood and waterlogging. Except for a series of LID measures during the process of SCC, corresponding control scheme of river-lake system should be established to realize water-related targets. From the view of ecological sponge basin, this study presents the general idea of SCC both in and out of the unban built-up area and the corresponding control scheme of river-lake system: for the regions outside the built-up area, the main aim of SCC is to carry out the top-level design of urban flood control and waterlogging, establish the water security system outside the city for solving the problems including flood control, water resources, water environment and water ecology; for the built-up area, the main aim of SCC is to construct different kinds of urban sponge according to local conditions and develop multi-scale drainage system responding to different intensities of rainfall taking the river-lake system as the core. Taking Fenghuang County of Hunan Province as an example for the application research, the results indicate that, after the implementation of the control scheme of river-lake system: 1) together with other SCC measures including LID, the control rate of total annual runoff in Fenghuang County is expected to be 82.9% which meets the target requirement of 80%; 2) flood control and drainage standards in Fenghuang County can be increased from the current 10-year return to 20-year return; 3) urban and rural water supply

  20. Guidance and methodologies for managing digital instrumentation and control obsolescence

    International Nuclear Information System (INIS)

    O'Connor, Matthew; Geddes, Bruce; Kelley, Sean

    2015-01-01

    New nuclear plant technology will rely heavily, if not exclusively, on digital equipment. Obsolescence of digital I and C equipment is an inevitable part of plant technology life cycle for new and existing plants. Developing an overall strategic plan can mitigate some of the risks associated with obsolescence. Moreover, when developed as part of an overall lifecycle management plan (LCMP), a strategic obsolescence management approach can identify steps that can be taken at early stages of the technology life cycle to cope proactively with the obsolescence of equipment. Recent work within the Advanced Nuclear Technology (ANT) program at the Electric Power Research Institute (EPRI) has developed guidance and methodologies for determining when digital obsolescence is likely to occur, the extent to which it can occur, the risks and impacts due to obsolescence, and strategies that can be used to minimize its effects, all in the context of system lifecycle management planning (LCMP). Worksheets for assessing obsolescence risks and the applicability and limitations of management strategies were developed as part of this work, and can be used to create or supplement a strategic obsolescence management plan. (author)

  1. A digital signal processor based rf control system for the TRIUMF ISAC RFQ prototype

    International Nuclear Information System (INIS)

    Fong, K.; Fang, S.; Laverty, M.

    1996-01-01

    A stand alone digital signal processor is used to control the RFQ prototype in the TRIUMF ISAC development program. The advantage of a digital control system over the traditional analogue system is that it offers the higher degree of flexibility necessary for a development system. For this application the system is designed to have the outward appearance of an analogue system, and uses dials, knobs, and switches as the operator interface. The digital signal processor is used as a feedback controller during CW rf operation, with the feedback gain parameters continually adjustable. It is also able to perform the same regulation during pulsed operation, with additional feedforward compensation for initial pulse on duration. Using a low cost analogue-to-digital converter with a sample rate of 100 kHz, a regulation bandwidth of 10 kHz is achieved. (author)

  2. Digital TV-echelle spectrograph for simultaneous multielemental analysis using microcomputer control

    International Nuclear Information System (INIS)

    Davidson, J.B.; Case, A.L.

    1980-12-01

    A digital TV-echelle spectrograph with microcomputer control was developed for simultaneous multielemental analysis. The optical system is a commercially available unit originally equipped for film and photomultiplier (single element) readout. The film port was adapted for the intensifier camera. The camera output is digitized and stored in a microcomputer-controlled, 512 x 512 x 12 bit memory and image processor. Multiple spectra over the range of 200 to 800 nm are recorded in a single exposure. Spectra lasting from nanoseconds to seconds are digitized and stored in 0.033 s and displayed on a TV monitor. An inexpensive microcomputer controls the exposure, reads and displays the intensity of predetermined spectral lines, and calculates wavelengths of unknown lines. The digital addresses of unknown lines are determined by superimposing a cursor on the TV display. The microcomputer also writes into memory wavelength fiducial marks for alignment of the TV camera

  3. Analysis of Adaptive Control Scheme in IEEE 802.11 and IEEE 802.11e Wireless LANs

    Science.gov (United States)

    Lee, Bih-Hwang; Lai, Hui-Cheng

    In order to achieve the prioritized quality of service (QoS) guarantee, the IEEE 802.11e EDCAF (the enhanced distributed channel access function) provides the distinguished services by configuring the different QoS parameters to different access categories (ACs). An admission control scheme is needed to maximize the utilization of wireless channel. Most of papers study throughput improvement by solving the complicated multidimensional Markov-chain model. In this paper, we introduce a back-off model to study the transmission probability of the different arbitration interframe space number (AIFSN) and the minimum contention window size (CWmin). We propose an adaptive control scheme (ACS) to dynamically update AIFSN and CWmin based on the periodical monitoring of current channel status and QoS requirements to achieve the specific service differentiation at access points (AP). This paper provides an effective tuning mechanism for improving QoS in WLAN. Analytical and simulation results show that the proposed scheme outperforms the basic EDCAF in terms of throughput and service differentiation especially at high collision rate.

  4. Tailoring automatic exposure control toward constant detectability in digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Salvagnini, Elena, E-mail: elena.salvagnini@uzleuven.be [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Bosmans, Hilde [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium); Struelens, Lara [SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Marshall, Nicholas W. [Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium)

    2015-07-15

    Purpose: The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. Methods: The default “OPDOSE” AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d′), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (T{sub t}) in the European guidelines for the 0.1 mm diameter disc (i.e., T{sub t} ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (T{sub t}), calculated detectability (d′), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. Results: The default OPDOSE AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d′ 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d′), respectively

  5. A quality control system for digital elevation data

    Science.gov (United States)

    Knudsen, Thomas; Kokkendorf, Simon; Flatman, Andrew; Nielsen, Thorbjørn; Rosenkranz, Brigitte; Keller, Kristian

    2015-04-01

    In connection with the introduction of a new version of the Danish national coverage Digital Elevation Model (DK-DEM), the Danish Geodata Agency has developed a comprehensive quality control (QC) and metadata production (MP) system for LiDAR point cloud data. The architecture of the system reflects its origin in a national mapping organization where raw data deliveries are typically outsourced to external suppliers. It also reflects a design decision of aiming at, whenever conceivable, doing full spatial coverage tests, rather than scattered sample checks. Hence, the QC procedure is split in two phases: A reception phase and an acceptance phase. The primary aim of the reception phase is to do a quick assessment of things that can typically go wrong, and which are relatively simple to check: Data coverage, data density, strip adjustment. If a data delivery passes the reception phase, the QC continues with the acceptance phase, which checks five different aspects of the point cloud data: Vertical accuracy Vertical precision Horizontal accuracy Horizontal precision Point classification correctness The vertical descriptors are comparatively simple to measure: The vertical accuracy is checked by direct comparison with previously surveyed patches. The vertical precision is derived from the observed variance on well defined flat surface patches. These patches are automatically derived from the road centerlines registered in FOT, the official Danish map data base. The horizontal descriptors are less straightforward to measure, since potential reference material for direct comparison is typically expected to be less accurate than the LiDAR data. The solution selected is to compare photogrammetrically derived roof centerlines from FOT with LiDAR derived roof centerlines. These are constructed by taking the 3D Hough transform of a point cloud patch defined by the photogrammetrical roof polygon. The LiDAR derived roof centerline is then the intersection line of the two primary

  6. Importance Sampling Based Decision Trees for Security Assessment and the Corresponding Preventive Control Schemes: the Danish Case Study

    DEFF Research Database (Denmark)

    Liu, Leo; Rather, Zakir Hussain; Chen, Zhe

    2013-01-01

    and adopts a methodology of importance sampling to maximize the information contained in the database so as to increase the accuracy of DT. Further, this paper also studies the effectiveness of DT by implementing its corresponding preventive control schemes. These approaches are tested on the detailed model......Decision Trees (DT) based security assessment helps Power System Operators (PSO) by providing them with the most significant system attributes and guiding them in implementing the corresponding emergency control actions to prevent system insecurity and blackouts. DT is obtained offline from time...

  7. A Nonlinear Digital Control Solution for a DC/DC Power Converter

    Science.gov (United States)

    Zhu, Minshao

    2002-01-01

    A digital Nonlinear Proportional-Integral-Derivative (NPID) control algorithm was proposed to control a 1-kW, PWM, DC/DC, switching power converter. The NPID methodology is introduced and a practical hardware control solution is obtained. The design of the controller was completed using Matlab (trademark) Simulink, while the hardware-in-the-loop testing was performed using both the dSPACE (trademark) rapid prototyping system, and a stand-alone Texas Instruments (trademark) Digital Signal Processor (DSP)-based system. The final Nonlinear digital control algorithm was implemented and tested using the ED408043-1 Westinghouse DC-DC switching power converter. The NPID test results are discussed and compared to the results of a standard Proportional-Integral (PI) controller.

  8. Automation of extrusion of porous cable products based on a digital controller

    Science.gov (United States)

    Chostkovskii, B. K.; Mitroshin, V. N.

    2017-07-01

    This paper presents a new approach to designing an automated system for monitoring and controlling the process of applying porous insulation material on a conductive cable core, which is based on using structurally and parametrically optimized digital controllers of an arbitrary order instead of calculating typical PID controllers using known methods. The digital controller is clocked by signals from the clock length sensor of a measuring wheel, instead of a timer signal, and this provides the robust properties of the system with respect to the changing insulation speed. Digital controller parameters are tuned to provide the operating parameters of the manufactured cable using a simulation model of stochastic extrusion and are minimized by moving a regular simplex in the parameter space of the tuned controller.

  9. Demonstrative fractional order - PID controller based DC motor drive on digital platform.

    Science.gov (United States)

    Khubalkar, Swapnil W; Junghare, Anjali S; Aware, Mohan V; Chopade, Amit S; Das, Shantanu

    2017-09-21

    In industrial drives applications, fractional order controllers can exhibit phenomenal impact due to realization through digital implementation. Digital fractional order controllers have created wide scope as it possess the inherent advantages like robustness against the plant parameter variation. This paper provides brief design procedure of fractional order proportional-integral-derivative (FO-PID) controller through the indirect approach of approximation using constant phase technique. The new modified dynamic particle swarm optimization (IdPSO) technique is proposed to find controller parameters. The FO-PID controller is implemented using floating point digital signal processor. The building blocks are designed and assembled with all peripheral components for the 1.5kW industrial DC motor drive. The robust operation for parametric variation is ascertained by testing the controller with two separately excited DC motors with the same rating but different parameters. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Digital control system of a steam generator water level by LQG optimal method

    International Nuclear Information System (INIS)

    Lee, Yoon Joon

    1993-01-01

    A digital control system for the steam generator water level control is developed using LQG optimal design method. To describe the more realistic situaton, a feedwater valve actuator is assumed to be of the first order lagger and is included in the overall control system. By composing the digital control circuit in such a way that the overall control system consists of two sub-systems of feedwater station and feedback loop digital controller, the design procedure is divided into two independent steps. The feedwater station system is described in the error dynamics of an ordinary regulator system. The optimal gains are obtained by LQ method which imposes the constraints of the feedwater valve motion as well as on the output deviations. Developed also is a Kalman observer on account of the flow measurement uncertainty at low power. Then a digital controller on the feedback loop is designed so that the system maintains the same stability margins for all power ranges. The simulation results show thst the optimal digital system has a good control characteristics despite the adverse dynamics of a steam generator at low power. (Author)

  11. Development of age-estimation system using thermoluminescence. Constant rising temperature control with optimal digital control

    International Nuclear Information System (INIS)

    Tamaki, Shiro; Oshiro, Naoki; Yamamoto, Tetsuhiko; Kinjo, Hiroshi; Taira, Hatsuo; Tanahara, Akira.

    1994-01-01

    Thermoluminescence (TL) is a calorescence phenomenon observed while heating minerals. TL intensity depends on the total quantity of radiation dose in the past. Due to this characteristic, measuring of TL intensity of natural minerals has been paid much attention as a useful method of age-estimation in archaeological and geological fields. Since TL intensity depends on the heating rate of the specimen, a constant rising temperature control system is necessary. But, even a commercial apparatus for TL measurement usually fails the rising temperature characteristic. This paper progress a new TL age-estimating method. To establish for this, a temperature control system is designed and a measurement system for TL intensity is developed. The optimal digital feedback control algorithm based on impulse response of the system is applied to this temperature control system. The control result shows that the system can precisely control the constant rising temperature within permissible error of 1 degree for the temperature range of 150-400 degree centigrade. Then the system is introduced to TL age-estimation system of fossil-oyster. The age is estimated by calculating the proportion of the annual cumulative dose at sampling area to the sum of natural cumulative dose that obtained by integrated TL intensity measured at a constant rising temperature. This result is reasonable. (author)

  12. Frequency control circuit for all-digital phase-lock loops

    Science.gov (United States)

    Anderson, T. O.

    1973-01-01

    Phase-lock loop references all its operations to fixed high-frequency service clock operating at highest speed which digital circuits permit. Wide-range control circuit provides linear control of frequency of reference signal. It requires only two counters in combination with control circuit consisting only of flip-flop and gate.

  13. F2AC: A Lightweight, Fine-Grained, and Flexible Access Control Scheme for File Storage in Mobile Cloud Computing

    Directory of Open Access Journals (Sweden)

    Wei Ren

    2016-01-01

    Full Text Available Current file storage service models for cloud servers assume that users either belong to single layer with different privileges or cannot authorize privileges iteratively. Thus, the access control is not fine-grained and flexible. Besides, most access control methods at cloud servers mainly rely on computationally intensive cryptographic algorithms and, especially, may not be able to support highly dynamic ad hoc groups with addition and removal of group members. In this paper, we propose a scheme called F2AC, which is a lightweight, fine-grained, and flexible access control scheme for file storage in mobile cloud computing. F2AC can not only achieve iterative authorization, authentication with tailored policies, and access control for dynamically changing accessing groups, but also provide access privilege transition and revocation. A new access control model called directed tree with linked leaf model is proposed for further implementations in data structures and algorithms. The extensive analysis is given for justifying the soundness and completeness of F2AC.

  14. Energy saving scheme for internet provision in rural africa: LESS

    CSIR Research Space (South Africa)

    Masonta, MT

    2010-05-01

    Full Text Available are among the reasons for the growing digital divide gap. In this paper, we present a Low cost Energy Saving Scheme Medium Access Control (LESS-MAC) protocol for broadband wireless networks suitable for deployments in energy-constrained rural areas. Our...

  15. Measures to enhance the reliability of digital reactor instrumentation and control system

    International Nuclear Information System (INIS)

    Li Duo; Zhang Liangju

    2005-01-01

    The instrumentation and control (I and C) system of an in-constriction research reactor is fully based on digital technology, which greatly improves system performance in many aspects such as MMI, data processing accurately, centralized control and monitoring ability, and maintainability. The reliability should be an essential issue for the successfulness of a digital I and C. This paper describes measures taken in the design of the reactor I and C to enhance the overall reliability, including distributed data processing; and control functions, redundancy, autonomous control, and diversified MMI, which would greatly contribute to the system reliability. (authors)

  16. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2011-01-01

    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling...... is described. Results show that digital control can compete with the analog one in efficiency, PFC and THD....

  17. Crystal Phase Quantum Well Emission with Digital Control

    DEFF Research Database (Denmark)

    Assali, S.; Laehnemann, J.; Vu, Thi Thu Trang

    2017-01-01

    -blende (ZB) and wurtzite (WZ) phases. Such a crystal phase switching results in the formation of crystal phase quantum wells (CPQWs) and quantum dots (CPQDs). For GaP CPQWs, the inherent electric fields due to the discontinuity of the spontaneous polarization at the WZ/ZB junctions lead to the confinement...... of both types of charge carriers at the opposite interfaces of the WZ/ZB/WZ structure. This confinement leads to a novel type of transition across a ZB flat plate barrier. Here, we show digital tuning of the visible emission of WZ/ZB/WZ CPQWs in a GaP nanowire by changing the thickness of the ZB barrier...

  18. Network device interface for digitally interfacing data channels to a controller via a network

    Science.gov (United States)

    Ellerbrock, Philip J. (Inventor); Grant, Robert L. (Inventor); Konz, Daniel W. (Inventor); Winkelmann, Joseph P. (Inventor)

    2009-01-01

    A communications system and method are provided for digitally connecting a plurality of data channels, such as sensors, actuators, and subsystems, to a controller using a network bus. The network device interface interprets commands and data received from the controller and polls the data channels in accordance with these commands. Specifically, the network device interface receives digital commands and data from the controller, and based on these commands and data, communicates with the data channels to either retrieve data in the case of a sensor or send data to activate an actuator. Data retrieved from the sensor is converted into digital signals and transmitted to the controller. Network device interfaces associated with different data channels can coordinate communications with the other interfaces based on either a transition in a command message sent by the bus controller or a synchronous clock signal.

  19. Optimal control of a wind turbine with digital fluid power transmission

    DEFF Research Database (Denmark)

    Pedersen, Niels Henrik; Johansen, Per; Andersen, Torben O.

    2018-01-01

    Digital fluid power (DFP) technology may lead to a paradigm shift in large-scale transmission systems in, e.g., wind and wave energy. Therefore, the development of applicable control algorithms is of major importance, but is complicated by the non-smooth behavior of the DFP displacement machines....... The power throughput of a full stroke operated digital displacement machine is quantized by the number of pressure chambers. The dynamics of each pressure chamber may be described by highly nonlinear continuous differential equations, whereas the input is discretely updated and binary (active or inactive......) control theory. The control strategy is validated for control of a digital fluid power wind turbine transmission, where both a deterministic and a stochastic optimal controllers are synthesized. The study is based on the NREL 5-MW reference wind turbine, where its model is combined with a nonlinear model...

  20. Controlling Random Waves with Digital Building Blocks Based on Supersymmetry

    Science.gov (United States)

    Yu, Sunkyu; Piao, Xianji; Park, Namkyoo

    2017-11-01

    Harnessing multimode waves allows high information capacity through modal expansions. Although passive multimode devices for broadband responses have been demonstrated in momentum or frequency domains, the difficulty in achieving collective manipulation of all eigenmodes has hindered the implementation of digital multimode devices such as switching. Here we propose building blocks for digital switching of spatially random waves based on parity-converted supersymmetric pairs of multimode potentials. We reveal that unbroken supersymmetric transformations of any parity-symmetric potential derive the parity reversal of all eigenmodes, which allows the complete isolation of random waves in the "off" state. With two representative solvable potentials, building blocks for binary and many-valued logics are then demonstrated for random waves: a harmonic pair for binary switching of arbitrary wave fronts and a Pöschl-Teller pair for multilevel switching which implements fuzzy membership functions. Our results realizing the transfer of arbitrary wave fronts between wave elements will lay the foundation of high-bandwidth data processing.

  1. Cross-Layer Scheme to Control Contention Window for Per-Flow in Asymmetric Multi-Hop Networks

    Science.gov (United States)

    Giang, Pham Thanh; Nakagawa, Kenji

    The IEEE 802.11 MAC standard for wireless ad hoc networks adopts Binary Exponential Back-off (BEB) mechanism to resolve bandwidth contention between stations. BEB mechanism controls the bandwidth allocation for each station by choosing a back-off value from one to CW according to the uniform random distribution, where CW is the contention window size. However, in asymmetric multi-hop networks, some stations are disadvantaged in opportunity of access to the shared channel and may suffer severe throughput degradation when the traffic load is large. Then, the network performance is degraded in terms of throughput and fairness. In this paper, we propose a new cross-layer scheme aiming to solve the per-flow unfairness problem and achieve good throughput performance in IEEE 802.11 multi-hop ad hoc networks. Our cross-layer scheme collects useful information from the physical, MAC and link layers of own station. This information is used to determine the optimal Contention Window (CW) size for per-station fairness. We also use this information to adjust CW size for each flow in the station in order to achieve per-flow fairness. Performance of our cross-layer scheme is examined on various asymmetric multi-hop network topologies by using Network Simulator (NS-2).

  2. A Model Reference Adaptive Control/PID Compound Scheme on Disturbance Rejection for an Aerial Inertially Stabilized Platform

    Directory of Open Access Journals (Sweden)

    Xiangyang Zhou

    2016-01-01

    Full Text Available This paper describes a method to suppress the effect of nonlinear and time-varying mass unbalance torque disturbance on the dynamic performances of an aerial inertially stabilized platform (ISP. To improve the tracking accuracy and robustness of the ISP, a compound control scheme based on both of model reference adaptive control (MRAC and PID control methods is proposed. The dynamic model is first developed which reveals the unbalance torque disturbance with the characteristic of being nonlinear and time-varying. Then, the MRAC/PID compound controller is designed, in which the PID parameters are adaptively adjusted based on the output errors between the reference model and the actual system. In this way, the position errors derived from the prominent unbalance torque disturbance are corrected in real time so that the tracking accuracy is improved. To verify the method, the simulations and experiments are, respectively, carried out. The results show that the compound scheme has good ability in mass unbalance disturbance rejection, by which the system obtains higher stability accuracy compared with the PID method.

  3. A Maximum Efficiency Point Tracking Control Scheme Based on Different Cross Coupling of Dual-Receiver Inductive Power Transfer System

    Directory of Open Access Journals (Sweden)

    Ruikun Mai

    2017-02-01

    Full Text Available One of the most promising inductive power transfer applications is the wireless power supply for locomotives which may cancel the need for pantographs. In order to meet the dynamic and high power demands of wireless power supplies for locomotives, a relatively long transmitter track and multiple receivers are usually adopted. However, during the dynamic charging, the mutual inductances between the transmitter and receivers vary and the load of the locomotives also changes randomly, which dramatically affects the system efficiency. A maximum efficiency point tracking control scheme is proposed to improve the system efficiency against the variation of the load and the mutual inductances between the transmitter and receivers while considering the cross coupling between receivers. Firstly, a detailed theoretical analysis on dual receivers is carried out. Then a control scheme with three control loops is proposed to regulate the receiver currents to be the same, to regulate the output voltage and to search for the maximum efficiency point. Finally, a 2 kW prototype is established to validate the performance of the proposed method. The overall system efficiency (DC-DC efficiency reaches 90.6% at rated power and is improved by 5.8% with the proposed method under light load compared with the traditional constant output voltage control method.

  4. Report on Disclosure Issues Related to the Use of Copy Control and Digital Rights Management Technologies. OECD Digital Economy Papers, No. 115

    Science.gov (United States)

    OECD Publishing (NJ1), 2006

    2006-01-01

    This report analyses the disclosure issues raised by technically-imposed restrictions on the use of digital content. It focuses on the application of copy control and digital rights management technologies in three areas: copy-protected CDs; online music, and DVD regional coding. In each of these areas, the report examines the kinds of…

  5. Implementation of a digital feedwater control system at Dresden Nuclear Power Plant, Units 2 and 3: Final report

    International Nuclear Information System (INIS)

    Zapotocky, A.; Popovic, J.R.; Fournier, R.D.

    1988-12-01

    This report describes the Digital Feedwater Control System Implementation at the Dresden 2 or 3 Units of the BWR Nuclear Power Plant owned by the Commonwealth Edison Company. The digital system has been operational in Unit 3 since August 1986, and in Unit 2 since April 1987. The Bailey Control's Network 90 based digital control system replaced the obsolete GE/MAC 5000 analog control system in the reactor feedwater control loop as a ''like-for-like'' replacement. Operational experience from the Digital Feedwater Control installations has been good and the system demonstrated better performance than the old analog systems. 14 refs., 15 figs., 17 tabs

  6. Parameters-adjustable front-end controller in digital nuclear measurement system

    International Nuclear Information System (INIS)

    Hao Dejian; Zhang Ruanyu; Yan Yangyang; Wang Peng; Tang Changjian

    2013-01-01

    Background: One digitizer is used to implement a digital nuclear measurement for the acquisition of nuclear information. Purpose: A principle and method of a parameter-adjustable front-end controller is presented for the sake of reducing the quantitative errors while getting the maximum ENOB (effective number of bits) of ADC (analog-to-digital converter) during waveform digitizing, as well as reducing the losing counts. Methods: First of all, the quantitative relationship among the radiation count rate (n), the amplitude of input signal (V in ), the conversion scale of ADC (±V) and the amplification factor (A) was derived. Secondly, the hardware and software of the front-end controller were designed to fulfill matching the output of different detectors, adjusting the amplification linearly through the control of channel switching, and setting of digital potentiometer by CPLD (Complex Programmable Logic Device). Results: (1) Through the measurement of γ-ray of Am-241 under our digital nuclear measurement set-up with CZT detector, it was validated that the amplitude of output signal of detectors of RC feedback type could be amplified linearly with adjustable amplification by the front-end controller. (2) Through the measurement of X-ray spectrum of Fe-5.5 under our digital nuclear measurement set-up with Si-PIN detector, it was validated that the front-end controller was suitable for the switch resetting type detectors, by which high precision measurement under various count rates could be fulfilled. Conclusion: The principle and method of the parameter-adjustable front-end controller presented in this paper is correct and feasible. (authors)

  7. Method for evaluating operator inputs to digital controllers

    International Nuclear Information System (INIS)

    Venhuizen, J.R.

    1983-01-01

    Most industrial processes employ operator-interactive control systems. The performance of these control systems is influenced by the choice of control station (device through which operator enters control commands). While the importance of proper control-station selection is widely accepted, standard and simple selection methods are not available for the control station using color-graphics terminals. This paper describes a unique facility for evaluating the effectiveness of various control stations. In the facility, a process is simulated on a hybrid computer, color-graphics display terminals provide information to the operator, and different control stations accept input commands to control the simulation. Tests are being conducted to evaluate a keyboard, a graphics tablet, and a CRT touch panel for use as control stations on a nuclear power plant. Preliminary results indicate that our facility can be used to determine those situations where each type of station is advantageous

  8. Application of discrete function and software control flow to dependability assessment of embedded digital system

    International Nuclear Information System (INIS)

    Choi, Jong Gyun; Seong, Poong Hyun

    2001-01-01

    This article describes a combinatorial model for estimating the reliability of the embedded digital system by means of discrete function theory and software control flow. This model includes a coverage model for fault processing mechanisms implemented in digital system. Furthermore, the model considers the interaction between hardware and software. The fault processing mechanisms make it difficult for many types of components in digital system to be treated as binary state, good or bad. The discrete function theory provides a complete analysis of multi-state system as which the digital system can be regarded Through adaptation software control flow to discrete function theory, the HW/SW interaction is considered for estimation of the reliability of digital system. Using this model, we predict the reliability of one board controller in a digital system, Interposing Logic System(ILS), which is installed in YGN nuclear power units 3 and 4. Since the proposed model is general combinatinal model, the simplification of this model becomes a conservative model that treats the system as binary state. Moreover, if information for coverage factor of fault tolerance mechanisms implemented in system through fault injection experiment is obtained, this model can consider detailed interaction of system components

  9. Flight test of a digital controller used in a helicopter autoland system

    Science.gov (United States)

    Downing, David R.; Bryant, Wayne H.

    1987-01-01

    This paper describes the flight test evaluation of an advanced digital helicopter flight control system. The controller was designed using an optimal control design procedure for a fully coupled lateral and longitudinal vehicle model. Explicit integrals of the guidance error were included to produce a type 1 characteristic. Gain scheduling was used to account for changes in the vehicle dynamics. The digital controller was exercised by combining it with state estimators, a trajectory generator, and a closed-loop guidance algorithm to form a helicopter autoland system. A CH-47 tandem rotor helicopter was equipped with sensors, on-board digital flight computers, and electrohydraulic actuators. The system was exercised by automatically flying straight-in descending decelerating trajectories typcial of VFR manual landing approaches. A description of the test-ground facilities, the flight hardware and software, and the velocity and position tracking performance is included.

  10. Analysis of Process Capability on the Digital Control Board Batch Testing

    Directory of Open Access Journals (Sweden)

    Chun-Jiang SHUAI

    2014-03-01

    Full Text Available This paper introduces a process control method and analysis procedure. Current data for the digital control single board was obtained with the Statistical Process Control method for a TD outdoor base station. The pass rate and quality of the digital single board was obtained through a production process capability analysis. The improvements associated with the single board method have been put forward here in order to lay a foundation for the enhancement of the quality of several indices. Indices here include the index for process capability and processing accuracy.

  11. Molecular Control of Interdigital Cell Death and Cell Differentiation by Retinoic Acid during Digit Development

    Directory of Open Access Journals (Sweden)

    Martha Elena Díaz-Hernández

    2014-04-01

    Full Text Available The precise coordination of cell death and cell differentiation during the formation of developing digits is essential for generating properly shaped limbs. Retinoic acid (RA has a fundamental role in digit development; it promotes or inhibits the molecular expression of several critical genes. This control of gene expression establishes molecular cascades that enable both the commencement of cell death and the inhibition of cell differentiation. In this review, we focus on the antagonistic functions between RA and fibroblast growth factor (FGF signaling in the control of cell death and between RA and transforming growth factor beta (TGFβ signaling in the control of cell differentiation.

  12. Multi-agent model predictive control for transportation networks : Serial versus parallel schemes

    NARCIS (Netherlands)

    Negenborn, R.R.; De Schutter, B.; Hellendoorn, J.

    2006-01-01

    We consider the control of large-scale transportation networks, like road traffic networks, power distribution networks, water distribution networks, etc. Control of these networks is often not possible from a single point by a single intelligent control agent; instead control has to be performed

  13. Hardware aspects of safety critical digital computer based instrumentation and control systems

    International Nuclear Information System (INIS)

    Sudduth, A.L.

    1994-01-01

    During the last 20 years, instrumentation and control systems based on digital computer technology have come to be used widely throughout industry. Included are applications that are of a safety critical nature - that is, where the consequences of failure of a device or system could have substantial adverse impact on the public. The successful application of digital computer technology in the aerospace and process industries for monitoring and control, and the benefits that this technology offers when compared to the analog technology of 25 years ago, require that consideration be given to the more widespread application of digital computer technology in US nuclear stations as obsolete monitoring and control systems are replaced. The purpose of this paper is to examine hardware aspects of safety critical digital control and instrumentation systems. It will discuss how to achieve adequate measures of system reliability and how to ensure that the required level to reliability is achieved. Special techniques for design of the hardware architecture of a digital computer based monitoring and control system that are able to make the system single or even double failure proof are discussed. Examples of hardware architectures which achieve high reliability are given, including those currently in use in US nuclear stations or expected to be applied in the future

  14. Digital viscosity controller for fossil power plants; Controlador digital de viscosidad para plantas termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Bautista B, Amberto; Ocampo P, Carlos; Gutierrez A, Ruben; Madinaveitia V, Miguel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    Upon the need of increasing the efficiency of the existing fossil power plants in Mexico, the Instrumentation and Control Department of the Instituto de Investigaciones Electricas (IIE) designed and built a viscosity controller to enhance the fuel oil heating process. The system strategy, that allows the control either by temperature or viscosity considers, as an important element, the changing characteristics of the supplied fuels. The equipment that is utilized forms apart of the line Acquisition and Control System (ACS) developed at the same Institute, that has been successfully applied in other systems. [Espanol] Ante la necesidad de aumentar la eficiencia de las plantas termoelectricas existentes en Mexico, el Departamento de Instrumentacion y Control, del Instituto de Investigaciones Electricas (IIE), diseno y construyo un controlador de viscosidad para mejorar el proceso de calentamiento del aceite combustible. La estrategia del sistema, que permite controlar ya sea por viscosidad o por temperatura, considera como elemento importante las caracteristicas cambiantes de los combustibles suministrados. El equipo que se utiliza forma parte de la linea SAC (sistema de adquisicion y control), desarrollada en el mismo Instituto, que se ha aplicado satisfactoriamente en otros sistemas.

  15. Study on control schemes of flexible steering system of a multi-axle all-wheel-steering robot

    Directory of Open Access Journals (Sweden)

    Pingxia Zhang

    2016-05-01

    Full Text Available It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.

  16. A Design to Digitalize Hydraulic Cylinder Control of a Machine Tool ...

    African Journals Online (AJOL)

    Conventionally hydraulic piston - cylinder servos are actuated using analogue controls for machine tool axis drives. In this paper a design of the axis control system of an NC milling machine which employs a small stepping motor to digitally actuated hydraulic piston - cylinder servo drives existing on the machines Y-axis is ...

  17. Descripción de los sistemas de control digital de procesos

    Directory of Open Access Journals (Sweden)

    Adolfo Mora Villate

    1986-01-01

    Full Text Available Este articulo se ocupa de exponer a grandes rasgos las funciones que cumplen los computadores aplicados al control de procesos Industriales, así como de presentar las principales configuraciones de los sistemas de control digital de procesos.

  18. A New Coordinated Voltage Control Scheme for Offshore AC Grid of HVDC Connected Offshore Wind Power Plants

    DEFF Research Database (Denmark)

    Sakamuri, Jayachandra N.; Cutululis, Nicolaos Antonio; Rather, Zakir Hussain

    2015-01-01

    This paper proposes a coordinated voltage control scheme (CVCS) which enhances the voltage ride through (VRT) capability of an offshore AC grid comprised of a cluster of offshore wind power plants (WPP) connected through AC cables to the offshore voltage source converter based high voltage DC (VSC......-HVDC) converter station. Due to limited short circuit power contribution from power electronic interfaced variable speed wind generators and with the onshore main grid decoupled by the HVDC link, the offshore AC grid becomes more vulnerable to dynamic voltage events. Therefore, a short circuit fault...... in the offshore AC Grid is likely to have significant implications on the voltage of the offshore AC grid, hence on the power flow to the onshore mainland grid. The proposed CVCS integrates individual local reactive power control of wind turbines and of the HVDC converter with the secondary voltage controller...

  19. Analysis of field-oriented controlled induction motor drives under sensor faults and an overview of sensorless schemes.

    Science.gov (United States)

    Arun Dominic, D; Chelliah, Thanga Raj

    2014-09-01

    To obtain high dynamic performance on induction motor drives (IMD), variable voltage and variable frequency operation has to be performed by measuring speed of rotation and stator currents through sensors and fed back them to the controllers. When the sensors are undergone a fault, the stability of control system, may be designed for an industrial process, is disturbed. This paper studies the negative effects on a 12.5 hp induction motor drives when the field oriented control system is subjected to sensor faults. To illustrate the importance of this study mine hoist load diagram is considered as shaft load of the tested machine. The methods to recover the system from sensor faults are discussed. In addition, the various speed sensorless schemes are reviewed comprehensively. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Secure and Efficient Access Control Scheme for Wireless Sensor Networks in the Cross-Domain Context of the IoT

    Directory of Open Access Journals (Sweden)

    Ming Luo

    2018-01-01

    Full Text Available Nowadays wireless sensor network (WSN is increasingly being used in the Internet of Things (IoT for data collection, and design of an access control scheme that allows an Internet user as part of IoT to access the WSN becomes a hot topic. A lot of access control schemes have been proposed for the WSNs in the context of the IoT. Nevertheless, almost all of these schemes assume that communication nodes in different network domains share common system parameters, which is not suitable for cross-domain IoT environment in practical situations. To solve this shortcoming, we propose a more secure and efficient access control scheme for wireless sensor networks in the cross-domain context of the Internet of Things, which allows an Internet user in a certificateless cryptography (CLC environment to communicate with a sensor node in an identity-based cryptography (IBC environment with different system parameters. Moreover, our proposed scheme achieves known session-specific temporary information security (KSSTIS that most of access control schemes cannot satisfy. Performance analysis is given to show that our scheme is well suited for wireless sensor networks in the cross-domain context of the IoT.

  1. Wireless Digital Control and Synchronization of Master-Slave Multiple Motors Using ARM Microcontroller

    OpenAIRE

    Pratiksha Shingade; Arati Dalavi

    2014-01-01

    The co-ordination and synchronization control of motion of multiple motors is a challenging problem, since the synchronization of each individual motor can be influenced by many factors. This paper presents the concept and implementation of a scheme that uses a real time control approach to realize drive synchronization of the multiple motors. The basic principle of the control is the speed of both master and slave are measured and compared in such a way to get speed synchroni...

  2. Simulation of Digital Control Computer of Nuclear Power Plant Based on Virtual Machine Technology

    International Nuclear Information System (INIS)

    Hou, Xue Yan; Li, Shu; Li, Qing

    2011-01-01

    Based on analyzing DCC (Digital Control Computer) instruction sets, memory map, display controllers and I/O system, virtual machine of DCC (abbr. VM DCC) has been developed. The executive and control programs, same as running on NPP (Nuclear Power Plant) unit's DCC, can run on the VM DCC smoothly and get same control results. Dual VM DCC system has been successfully applied in NPP FSS(Full Scope Simulator) training. It not only improves FSS's fidelity but also makes maintaining easier

  3. Digital Distributed Control System Design: Control Policy for Shared Objects in HTR-PM

    International Nuclear Information System (INIS)

    Zhou Shuqiao; Huang Xiaojin

    2014-01-01

    HTR-PM is an HTR demonstration plant with a structure of two modules feeding one steam turbine. Compared with the structure of one single reactor feeding one turbine, there are more devices shared between these two modules. When they are operated, the shared components are prone to introduce collisions or even logical deadlocks for different technical processes. The future commercial HTR-PM plants are supposed to comprise more modules for a larger turbine, thus the collision problem introduced by the shared components may become severer. Therefore, how to design suitable policies in the distributed control system (DCS) to relieve the collisions during using these shared devices is a new and also a very important problem. In this paper, the classifications of the shared devices are first addressed, and then how to identify the shared objects of an NPP is proposed. Furthermore, a general model for the control logic design is proposed, taking into consideration the collision avoidance, time delay and fairness. The example of how to apply the schemes to relieve the conflicts and deadlocks in the processes of using the shared devices in fuel element cycling system is illustrated. (author)

  4. Secure and Efficient Access Control Scheme for Wireless Sensor Networks in the Cross-Domain Context of the IoT

    OpenAIRE

    Luo, Ming; Luo, Yi; Wan, Yuwei; Wang, Ze

    2018-01-01

    Nowadays wireless sensor network (WSN) is increasingly being used in the Internet of Things (IoT) for data collection, and design of an access control scheme that allows an Internet user as part of IoT to access the WSN becomes a hot topic. A lot of access control schemes have been proposed for the WSNs in the context of the IoT. Nevertheless, almost all of these schemes assume that communication nodes in different network domains share common system parameters, which is not suitable for cros...

  5. Results and Insights on the Impact of Smoke on Digital Instrumentation and Control

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, T. J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nowlen, S. P. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2001-01-31

    Smoke can cause interruptions and upsets in active electronics. Because nuclear power plants are replacing analog with digital instrumentation and control systems, qualification guidelines for new systems are being reviewed for severe environments such as smoke and electromagnetic interference. Active digital systems, individual components, and active circuits have been exposed to smoke in a program sponsored by the U.S. Nuclear Regulatory Commission. The circuits and systems were all monitored during the smoke exposure, indicating any immediate effects of the smoke. The major effect of smoke has been to increase leakage currents (through circuit bridging across contacts and leads) and to cause momentary upsets and failures in digital systems. This report summarizes two previous reports and presents new results from conformal coating, memory chip, and hard drive tests. The report describes practices for mitigation of smoke damage through digital system design, fire barriers, ventilation, fire suppressants, and post fire procedures.

  6. An adaptive optimisation scheme for controlling air flow process with satisfactory transient performance

    Directory of Open Access Journals (Sweden)

    Sivakumar Dakshinamurthy

    2010-07-01

    Full Text Available A non-identifier-based adaptive PI controller is designed using a gradient approach to improve the performance of a control system when device aging and environmental factors degrade the efficiency of the process. The design approach is based on the model reference adaptive control technique. The controller drives the difference (error between the process response and desired model output to zero asymptotically at a rate constrained by the desired characteristics of the model. The tuning rules are designed and justified for a non-linear process with dominant dynamics of second order. The advantage of this method for tracking and regulation compared to adaptive MIT control was validated in real time by conducting experiments on a laboratory air flow control system using the dSPACE interface in the SIMULINK software. The experimental results show that the process with adaptive PI controller has better dynamic performance and robustness than that with traditional adaptive MIT controller.

  7. Evaluation of the weekly quality control of a digital mammography machine; Evaluacion del control de calidad semanal de un mamografo digital

    Energy Technology Data Exchange (ETDEWEB)

    Angulo Pain, E.; Ramos Caballero, L. J.; Urena Llinares, A.; Iborra Oquendo, M. A.; Quinones Rodriguez, L. A.; Castro Ramirez, I.; Gonzalez Aquino, P.; Aguirre Huelga, M. J.

    2013-07-01

    In the new edition of the PCCRD (2011) has been established as weekly quality control testing for digital mammography equipment the analysis of artifacts from the team and defective items in the DR, the constancy of the functioning of the CAE, the accuracy of the thickness determined by the compression system, constancy in the uniformity and quality of the image. The objective of the study is to evaluate data collected during the first year of operation of the equipment. (Author)

  8. An adaptive optimisation scheme for controlling air flow process with satisfactory transient performance

    OpenAIRE

    Sivakumar Dakshinamurthy

    2010-01-01

    A non-identifier-based adaptive PI controller is designed using a gradient approach to improve the performance of a control system when device aging and environmental factors degrade the efficiency of the process. The design approach is based on the model reference adaptive control technique. The controller drives the difference (error) between the process response and desired model output to zero asymptotically at a rate constrained by the desired characteristics of the model. The tuning r...

  9. Digital combined instrument transformer for automated electric power supply control systems of mining companies

    Science.gov (United States)

    Topolsky, D. V.; Gonenko, T. V.; Khatsevskiy, V. F.

    2017-10-01

    The present paper discusses ways to solve the problem of enhancing operating efficiency of automated electric power supply control systems of mining companies. According to the authors, one of the ways to solve this problem is intellectualization of the electric power supply control system equipment. To enhance efficiency of electric power supply control and electricity metering, it is proposed to use specially designed digital combined instrument current and voltage transformers. This equipment conforms to IEC 61850 international standard and is adapted for integration into the digital substation structure. Tests were performed to check conformity of an experimental prototype of the digital combined instrument current and voltage transformer with IEC 61850 standard. The test results have shown that the considered equipment meets the requirements of the standard.

  10. BacNet and Analog/Digital Interfaces of the Building Controls Virtual Testbed

    Energy Technology Data Exchange (ETDEWEB)

    Nouidui, Thierry Stephane [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Wetter, Michael [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Li, Zhengwei [Georgia Inst. of Technology, Atlanta, GA (United States); Pang, Xiufeng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Bhattacharya, Prajesh [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Haves, Philip [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-11-01

    This paper gives an overview of recent developments in the Building Controls Virtual Test Bed (BCVTB), a framework for co-simulation and hardware-in-the-loop. First, a general overview of the BCVTB is presented. Second, we describe the BACnet interface, a link which has been implemented to couple BACnet devices to the BCVTB. We present a case study where the interface was used to couple a whole building simulation program to a building control system to assess in real-time the performance of a real building. Third, we present the ADInterfaceMCC, an analog/digital interface that allows a USB-based analog/digital converter to be linked to the BCVTB. In a case study, we show how the link was used to couple the analog/digital converter to a building simulation model for local loop control.

  11. Compensation of the effects of muscle fatigue on EMG-based control using fuzzy rules based scheme.

    Science.gov (United States)

    Lalitharatne, Thilina Dulantha; Hayashi, Yoshiaki; Teramoto, Kenbu; Kiguchi, Kazuo

    2013-01-01

    Estimation of the correct motion intention of the user is very important for most of the Electromyography (EMG) based control applications such as prosthetics, power-assist exoskeletons, rehabilitation and teleoperation robots. On the other hand, safety and long term reliability are also vital for those applications, as they interact with human users. By considering these requirements, many EMG-based control applications have been proposed and developed. However, there are still many challenges to be addressed in the case of EMG based control systems. One of the challenges that had not been considered in such EMG-based control in common is the muscle fatigue. The muscle fatiguing effects of the user can deteriorate the effectiveness of the EMG-based control in the long run, which makes the EMG-based control to produce less accurate results. Therefore, in this study we attempted to develop a fuzzy rule based scheme to compensate the effects of muscle fatigues on EMG based control. Fuzzy rule based weights have been estimated based on time and frequency domain features of the EMG signals. Eventually, these weights have been used to modify the controller output according with the muscle fatigue condition in the muscles. The effectiveness of the proposed method has been evaluated by experiments.

  12. High-performance adaptive intelligent Direct Torque Control schemes for induction motor drives

    Directory of Open Access Journals (Sweden)

    Vasudevan M.

    2005-01-01

    Full Text Available This paper presents a detailed comparison between viable adaptive intelligent torque control strategies of induction motor, emphasizing advantages and disadvantages. The scope of this paper is to choose an adaptive intelligent controller for induction motor drive proposed for high performance applications. Induction motors are characterized by complex, highly non-linear, time varying dynamics, inaccessibility of some states and output for measurements and hence can be considered as a challenging engineering problem. The advent of torque and flux control techniques have partially solved induction motor control problems, because they are sensitive to drive parameter variations and performance may deteriorate if conventional controllers are used. Intelligent controllers are considered as potential candidates for such an application. In this paper, the performance of the various sensor less intelligent Direct Torque Control (DTC techniques of Induction motor such as neural network, fuzzy and genetic algorithm based torque controllers are evaluated. Adaptive intelligent techniques are applied to achieve high performance decoupled flux and torque control. This paper contributes: i Development of Neural network algorithm for state selection in DTC; ii Development of new algorithm for state selection using Genetic algorithm principle; and iii Development of Fuzzy based DTC. Simulations have been performed using the trained state selector neural network instead of conventional DTC and Fuzzy controller instead of conventional DTC controller. The results show agreement with those of the conventional DTC.

  13. Digital, remote control system for a 2-MW research reactor

    International Nuclear Information System (INIS)

    Battle, R.E.; Corbett, G.K.

    1988-01-01

    A fault-tolerant programmable logic controller (PLC) and operator workstations have been programmed to replace the hard-wired relay control system in the 2-MW Bulk Shielding Reactor (BSR) at Oak Ridge National Laboratory. In addition to the PLC and remote and local operator workstations, auxiliary systems for remote operation include a video system, an intercom system, and a fiber optic communication system. The remote control station, located at the High Flux Isotope Reactor 2.5 km from the BSR, has the capability of rector startup and power control. The system was designed with reliability and fail-safe features as important considerations. 4 refs., 3 figs

  14. Digitally controlled droplet microfluidic system based on electrophoretic actuation

    Science.gov (United States)

    Im, Do Jin; Yoo, Byeong Sun; Ahn, Myung Mo; Moon, Dustin; Kang, In Seok

    2012-11-01

    Most researches on direct charging and the subsequent manipulation of a charged droplet were focused on an on-demand sorting in microchannel where carrier fluid transports droplets. Only recently, an individual actuation of a droplet without microchannel and carrier fluid was tried. However, in the previous work, the system size was too large and the actuation voltage was too high (1.5 kV), which limits the applicability of the technology to mobile use. Therefore, in the current research, we have developed a miniaturized digital microfluidic system based on the electrophoresis of a charged droplet (ECD). By using a pin header socket for an array of electrodes, much smaller microfluidic system can be made from simple fabrication process with low cost. A full two dimensional manipulation (0.4 cm/s) of a droplet (300 nL) suspended in silicone oil (6 cSt) and multiple droplet actuation have been performed with reasonable actuation voltage (300 V). By multiple droplet actuation and coalescence, a practical biochemical application also has been demonstrated. We hope the current droplet manipulation method (ECD) can be a good alternative or complimentary technology to the conventional ones and therefore contributes to the development of droplet microfluidics. This work has been supported by BK21 program of the Ministry of Education, Science and Technology (MEST) of Korea.

  15. Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak

    International Nuclear Information System (INIS)

    Litaudon, X.; Moreau, D.; Bizarro, J.P.; Hoang, G.T.; Kupfer, K.; Peysson, Y.; Shkarofsky, I.P.; Bonoli, P.

    1992-12-01

    The purpose of this work is to take into account and study the effect of the electric field profiles on the Lower Hybrid (LH) current drive efficiency during transient phases such as rampup. As a complement to the full ray-tracing / Fokker Planck studies, and for the purpose of optimization studies, we developed a simplified 1-D model based on the adjoint Karney-Fisch numerical results. This approach allows us to estimate the LH power deposition profile which would be required for ramping the current with prescribed rate, total current density profile (q-profile) and surface loop voltage. For rampup optimization studies, we can therefore scan the whole parameter space and eliminate a posteriori those scenarios which correspond to unrealistic deposition profiles. We thus obtain the time evolution of the LH power, minor radius of the plasma, volt-second consumption and total energy dissipated. Optimization can thus be performed with respect to any of those criteria. This scheme is illustrated by some numerical simulations performed with TORE-SUPRA and NET/ITER parameters. We conclude with a derivation of a simple and general scaling law for the flux consumption during the rampup phase

  16. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things

    Science.gov (United States)

    Yi, Meng; Chen, Qingkui; Xiong, Neal N.

    2016-01-01

    This paper considers the distributed access and control problem of massive wireless sensor networks’ data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate. PMID:27827878

  17. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things

    Directory of Open Access Journals (Sweden)

    Meng Yi

    2016-11-01

    Full Text Available This paper considers the distributed access and control problem of massive wireless sensor networks’ data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  18. An Effective Massive Sensor Network Data Access Scheme Based on Topology Control for the Internet of Things.

    Science.gov (United States)

    Yi, Meng; Chen, Qingkui; Xiong, Neal N

    2016-11-03

    This paper considers the distributed access and control problem of massive wireless sensor networks' data access center for the Internet of Things, which is an extension of wireless sensor networks and an element of its topology structure. In the context of the arrival of massive service access requests at a virtual data center, this paper designs a massive sensing data access and control mechanism to improve the access efficiency of service requests and makes full use of the available resources at the data access center for the Internet of things. Firstly, this paper proposes a synergistically distributed buffer access model, which separates the information of resource and location. Secondly, the paper divides the service access requests into multiple virtual groups based on their characteristics and locations using an optimized self-organizing feature map neural network. Furthermore, this paper designs an optimal scheduling algorithm of group migration based on the combination scheme between the artificial bee colony algorithm and chaos searching theory. Finally, the experimental results demonstrate that this mechanism outperforms the existing schemes in terms of enhancing the accessibility of service requests effectively, reducing network delay, and has higher load balancing capacity and higher resource utility rate.

  19. Efficiency and hardware comparison of analog control-based and digital control-based 70 W two-stage power factor corrector and DC-DC converters

    DEFF Research Database (Denmark)

    Török, Lajos; Munk-Nielsen, Stig

    2011-01-01

    A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling is d...... is described. Results show that digital control can compete with the analog one in efficiency, PFC and THD.......A comparison of an analog and a digital controller driven 70 W two-stage power factor corrector converter is presented. Both controllers are operated in average current-mode-control for the PFC and peak current control for the DC-DC converter. Digital controller design and converter modeling...

  20. Aplicación del control digital basado en hardware especifico para convertidores de potencia conmutados

    OpenAIRE

    Castro Martín, Ángel de

    2003-01-01

    El control de los convertidores conmutados de potencia ha sido resuelto tradicionalmente mediante técnicas analógicas. Sin embargo, la tendencia actual es la sustitución de estos controladores analógicos por otros digitales. La razón es que la electrónica digital ha crecido en prestaciones y bajado en precio a un ritmo mucho mayor que la electrónica analógica. Esta tendencia a la digitalización ha motivado el trabajo de esta tesis doctoral. Ya hay algunos precedentes en el control digital de ...