WorldWideScience

Sample records for beam feedback system

  1. Commissioning and Initial Performance of the LHC Beam-Based Feedback Systems

    CERN Document Server

    Boccardi, A; Calvo Giraldo, E; Denz, R; Gasior, M; Gonzalez, JL; Jackson, S; Jensen, LK; Jones, OR; King, Q; Kruk, G; Lamont, M; Page, S; Steinhagen, RJ; Wenninger, J

    2010-01-01

    The LHC deploys a comprehensive suite of beam-based feedbacks for safe and reliable machine operation. This contribution summarises the commissioning and early results of the LHC feedback control systems on orbit, tune, chromaticity, and energy. Their performance – strongly linked to the associated beam instrumentation, external beam perturbation sources and optics uncertainties – is evaluated and compared with the initial feedback design assumptions

  2. Design of the ILC Prototype FONT4 Digital Intra-Train Beam-Based Feedback System

    International Nuclear Information System (INIS)

    We present the design of the FONT4 digital intra-train beam position feedback system prototype and preliminary results of initial beam tests at the Accelerator Test Facility (ATF) at KEK. The feedback system incorporates a fast analogue beam position monitor (BPM) front-end signal processor, a digital feedback board, and a kicker driver amplifier. The short bunchtrain, comprising 3 electron bunches separated by c. 150ns, in the ATF extraction line was used to test components of the prototype feedback system

  3. A state variable approach to the BESSY II local beam-position-feedback system

    Energy Technology Data Exchange (ETDEWEB)

    Gilpatrick, J.D.; Khan, S.; Kraemer, D. [BESSY II, Berlin (Germany)

    1996-11-01

    At the BESSY II facility, stability of the electron beam position and angle near insertion devices (IDs) is of utmost importance. Disturbances due to ground motion could result in unwanted broad-bandwidth beam-jitter which decreases the electron (and resultant photon) beam`s effective brightness. Therefore, feedback techniques must be used. Operating over a frequency range of < 1- to > 100-Hz, a local feedback system will correct these beam-trajectory errors using the four bumps around IDs. This paper reviews how the state-variable feedback approach can be applied to real-time correction of these beam position and angle errors. A frequency-domain solution showing beam jitter reduction is presented. Finally, this paper reports results of a beam-feedback test at BESSY I.

  4. Transverse emittance blow-up from beam injection errors in synchrotrons with nonlinear feedback systems

    International Nuclear Information System (INIS)

    The problem of transverse emittance blow-up from beam injection errors in synchrotrons with nonlinear feedback systems is considered. The relative emittance growth is calculated for linear and nonlinear feedback transfer functions. Effects of an increase of the damping decrement of the beam coherent oscillations and of a decrease of the coherent transverse amplitude spread of different bunches in case of the damper with positive cubic term in the feedback transfer function are discussed

  5. A state variable approach to the BESSY II local beam-position-feedback system

    International Nuclear Information System (INIS)

    At the BESSY II facility, stability of the electron beam position and angle near insertion devices (IDs) is of utmost importance. Disturbances due to ground motion could result in unwanted broad-bandwidth beam-jitter which decreases the electron (and resultant photon) beam's effective brightness. Therefore, feedback techniques must be used. Operating over a frequency range of 100-Hz, a local feedback system will correct these beam-trajectory errors using the four bumps around IDs. This paper reviews how the state-variable feedback approach can be applied to real-time correction of these beam position and angle errors. A frequency-domain solution showing beam jitter reduction is presented. Finally, this paper reports results of a beam-feedback test at BESSY I

  6. The super collider transverse feedback system for suppression of the emittance growth and beam instabilities

    International Nuclear Information System (INIS)

    A super collider transverse feedback system designed to suppress injection errors, emittance growth due to external noises, and beam instabilities is considered. It is supposed that the feedback system should consist of two circuits: an injection damper operating just after injection and a super damper. To damp the emittance growth, the superdamper has to operate with the ultimate decrement close to the revolution frequency. The physics of such a feedback system and its main limitations are discussed. 9 refs.; 21 figs.; 1 tab

  7. Development of photon beam position feedback system based on two PBPMs at HLS

    International Nuclear Information System (INIS)

    In this paper, in order to stabilize the position and angle of the light source point, a new photon beam position feedback system based on the Photon Beam Position Monitors was developed on Hefei Light Source, and used to correct the position drift and angle variation of the light source at the same time. On introducing the feedback principle, the transfer function matrix is calibrated, indicating that the new system is workable and effective. (authors)

  8. Tests of the FONT3 Linear Collider Intra-Train Beam Feedback System at the ATF

    International Nuclear Information System (INIS)

    We report preliminary results of beam tests of the FONT3 Linear Collider intra-train position feedback system prototype at the Accelerator Test Facility at KEK. The feedback system incorporates a novel beam position monitor (BPM) processor with a latency below 5 nanoseconds, and a kicker driver amplifier with similar low latency. The 56 nanosecond-long bunchtrain in the ATF extraction line was used to test the prototype BPM processor. The achieved latency will allow a demonstration of intra-train feedback on timescales relevant even for the CLIC Linear Collider design

  9. An automatic beam steering system for the NSLS X-17T beam line using closed orbit feedback

    International Nuclear Information System (INIS)

    Initial observations of motion of the undulator radiation in the NSLS X-17T beam line clearly indicated that the beam had to be stabilized in both directions to be usable for the planned soft X-ray imaging experiments. The low frequency spectra of beam motion contained peaks in the range from dc to 60 Hz and at higher frequencies. A beam steering system employing closed orbit feedback has been designed and installed to stabilize the beam in both planes. In each plane of motion, beam position is measured with a beam position detector and a correction signal is fed back to a local four magnet orbit bump to dynamically control the angle of the radiation at the source. This paper describes the design and performance of the beam steering system

  10. Feedback control and beam diagnostic algorithms for a multiprocessor DSP system

    International Nuclear Information System (INIS)

    The multibunch longitudinal feedback system developed for use by PEP-II, ALS, and DAΦNE uses a parallel array of digital signal processors (DSPs) to calculate the feedback signals from measurements of beam motion. The system is designed with general-purpose programmable elements which allow many feedback operating modes as well as system diagnostics, calibrations, and accelerator measurements. The overall signal processing architecture of the system is illustrated. The real-time DSP algorithms and off-line postprocessing tools are presented. The problems in managing 320k samples of data collected in one beam transient measurement are discussed and our solutions are presented. Example software structures are presented showing the beam feedback process, techniques for modal analysis of beam motion (used to quantify growth and damping rates of instabilities), and diagnostic functions (such as timing adjustment of beam pick-up and kicker components). These operating techniques are illustrated with example results obtained from the system installed at the Advanced Light Source at LBL. copyright 1997 American Institute of Physics

  11. Development of a beam position detector for an orbit feedback system in SuperKEKB

    International Nuclear Information System (INIS)

    SuperKEKB, which is under construction at KEK, is an electron-positron collider aiming at 40 times larger luminosity of KEKB. Since a vertical design beam size at a collision point is as small as 50 nm in SuperKEKB, an orbit feedback system is essential for maintaining stable collision. A fast beam position detector is being developed for the orbit feedback system. Tentative target performance is a signal to noise ratio of 120dB at the input power of -3dBm and a signal bandwidth of 1 kHz. The detector consists of an analogue part to convert 509 MHz-beam-signal to 17 MHz-IF-signal and a digital part which has a ADC, two CIC decimation filters and a FIR filter. The paper describes results of laboratory measurement obtained so far and items to be improved for a final version. (author)

  12. Feedback system for suppression of the beam self-bunching in the U-70 accelerators

    International Nuclear Information System (INIS)

    Slow removal of proton beams from the U-70 proton synchrotron is complicated by the beam self-bunching effect, circulating on the magnetic field plateau. The effect is caused by the particles interaction with the operating 40-type oscillations of the disconnected HF-resonators, The system for suppression of this instability through the feedback channel (F C) by the beam, closed through one of the HF-resonators is proposed. Th principles of building the system are discussed and choice of its working parameters is explained. The results of the circuit-engineering modeling of the F C electrical scheme are presented. The proposed system is a version for technical solution of the problem on the beam self-bunching, considered within the frames of the program on the U-70 accelerator modernization

  13. Performance of the FONT3 Fast Analogue Intra-Train Beam-Based Feedback System at ATF

    International Nuclear Information System (INIS)

    We report results of beam tests of the FONT3 intra-train position feedback system prototype at the Accelerator Test Facility (ATF) at KEK. The feedback system incorporates a novel beam position monitor (BPM) processor with latency below 5 nanoseconds, and a kicker driver amplifier with similar low latency. The 56 nanosecond-long bunchtrain in the ATF extraction line was used to test the prototype feedback system. The achieved latency of 23ns provides a demonstration of intra-train feedback on very short timescales relevant even for the CLIC Linear Collider design

  14. Joint opportunistic beam and spectrum selection schemes for spectrum sharing systems with limited feedback

    KAUST Repository

    Sayed, Mostafa M.

    2014-11-01

    Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing an unlicensed secondary user (SU) to share the spectrum with a licensed primary user (PU) under acceptable interference levels to the primary receiver (PU-Rx). In this paper, we consider a secondary link composed of a secondary transmitter (SU-Tx) equipped with multiple antennas and a single-antenna secondary receiver (SU-Rx). The secondary link is allowed to share the spectrum with a primary network composed of multiple PUs communicating over distinct frequency spectra with a primary base station. We develop a transmission scheme where the SU-Tx initially broadcasts a set of random beams over all the available primary spectra for which the PU-Rx sends back the index of the spectrum with the minimum interference level, as well as information that describes the interference value, for each beam. Based on the feedback information on the PU-Rx, the SU-Tx adapts the transmitted beams and then resends the new beams over the best primary spectrum for each beam to the SU-Rx. The SU-Rx selects the beam that maximizes the received signal-to-interference-plus-noise ratio (SINR) to be used in transmission over the next frame. We consider three cases for the level of feedback information describing the interference level. In the first case, the interference level is described by both its magnitude and phase; in the second case, only the magnitude is considered; and in the third case, we focus on a q-bit description of its magnitude. In the latter case, we propose a technique to find the optimal quantizer thresholds in a mean-square-error sense. We also develop a statistical analysis for the SINR statistics and the capacity and bit error rate of the secondary link and present numerical results that study the impact of the different system parameters.

  15. The intensity feedback system at Heidelberg Ion-Beam Therapy Centre

    Energy Technology Data Exchange (ETDEWEB)

    Schoemers, Christian, E-mail: christian.schoemers@med.uni-heidelberg.de; Feldmeier, Eike; Naumann, Jakob; Panse, Ralf; Peters, Andreas; Haberer, Thomas

    2015-09-21

    At Heidelberg Ion-Beam Therapy Centre (HIT), more than 2500 tumour patients have been treated with charged particle beams since 2009 using the raster scanning method. The tumour is irradiated slice-by-slice, each slice corresponding to a different beam energy. For the particle dose of each raster point the pre-irradiation by more distal slices has to be considered. This leads to highly inhomogeneous dose distributions within one iso-energy slice. The particles are extracted from the synchrotron via transverse RF knock-out. A pure feed forward control cannot take into account fluence inhomogeneities or deal with intensity fluctuations. So far, fluctuations have been counteracted by a reduced scanning velocity. We now added a feedback loop to the extraction system. The dose monitoring ionisation chambers in front of the patient have been coupled to the extraction device in the synchrotron. Characterization and implementation of the intensity feedback system into the HIT facility is described here. By its implementation the treatment time has been reduced by 10% in average.

  16. Latest Performance Results from the FONT5 Intra-train Beam Position and Angle Feedback System at ATF2

    CERN Document Server

    Christian, G B; Bett, D R; Blaskovic Kraljevic, N; Burrows, P N; Davis, M R; Gerbershagen, A; Perry, C; Constance, B; Resta-Lopez, J

    2012-01-01

    A prototype Interaction Point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider, has been designed and tested on the extraction line of the KEK Accelerator Test Facility (ATF). The FONT5 intra-train feedback system aims to stabilize the beam orbit by correcting both the position and angle jitter in the vertical plane on bunch-tobunch time scales, providing micron-level stability at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kickerdrive amplifiers. The latest results from beam tests at ATF2 will be presented, including the system latency and correction performance.

  17. Broadband feedback systems for the damping of coherent beam instabilities in the stretcher ring ELSA; Breitbandige Feedback-Systeme zur Daempfung kohaerenter Strahlinstabilitaeten am Stretcherring ELSA

    Energy Technology Data Exchange (ETDEWEB)

    Roth, Andre

    2012-12-15

    At the Electron Stretcher Facility ELSA an upgrade of the internal beam current up to 200 mA would be desirable in order to increase the intensity of the extracted electron beam for the future experimental hadron physics program. However, such an upgrade is mainly limited by the excitation of coherent beam instabilities in the stretcher ring. As active counteraction, broadband bunch-by-bunch feedback-systems for the longitudinal, as well as for both transverse planes were installed. After detection of the motion of each of the 27 4 stored bunches via beam position monitors, the systems determine independent correction signals for each bunch using digital signal processors. The amplified correction signals are applied to the beam by means of broadband longitudinal and transverse kicker structures. The detailed setup, the commissioning procedure and measurement results of the damping performance of the systems are presented. In addition, the operation of the longitudinal system during the fast energy ramp of 4 GeV/s from 1.2 GeV to 3.2 GeV is investigated.

  18. Multi-bunch Feedback Systems

    CERN Document Server

    Lonza, M

    2014-01-01

    Coupled-bunch instabilities excited by the interaction of the particle beam with its surroundings can seriously limit the performance of circular particle accelerators. These instabilities can be cured by the use of active feedback systems based on sensors capable of detecting the unwanted beam motion and actuators that apply the feedback correction to the beam. Advances in electronic technology now allow the implementation of feedback loops using programmable digital systems. Besides important advantages in terms of flexibility and reproducibility, digital systems open the way to the use of novel diagnostic tools and additional features. We first introduce coupled-bunch instabilities, analysing the equation of motion of charged particles and the different modes of oscillation of a multi-bunch beam, showing how they can be observed and measured. Different types of feedback systems will then be presented as examples of real implementations that belong to the history of multi-bunch feedback systems. The main co...

  19. Linearizing Intra-Train Beam-Beam Deflection Feedback

    International Nuclear Information System (INIS)

    Beam-beam deflection feedback acting within the crossing time of a single bunch train may be needed to keep linear collider beams colliding at high luminosity. In a short-pulse machine such as the Next Linear Collider (NLC) this feedback must converge quickly to be useful. The non-linear nature of beam-beam deflection vs. beam-beam offset in these machines precludes obtaining both rapid convergence and a stable steady-state lock to beam offsets with a linear feedback algorithm. We show that a simply realizable programmable non-linear amplifier in the feedback loop can linearize the feedback loop, approximately compensating the beam-beam deflection non-linearity. Performance of a prototype non-linear amplifier is shown. Improvement of convergence and stability of the beam-beam feedback loop is simulated

  20. Beam position monitoring and feedback steering system at the photon factory

    International Nuclear Information System (INIS)

    A version of the beam steering servo system was used to vertically position and stabilize the synchrotron radiation beam at the Photon Factory. System components included a photon beam position monitor located 12 m from the bend magnet source point, a servo controller containing frequency compensation and gain circuits, and a 3-magnet orbital bump steering system. Two types of position monitor, one an ion chamber and the other on in-vacuum device, were used in the system. Vertical beam position noise spectra obtained from these monitors showed predominant peaks occurring at 14.5 Hz, 50 Hz, and at several other frequencies in the 1 to 100 Hz range. The closed-loop system was able to reduce low frequency positional offsets (< 0.1 Hz) by a factor of 1000, and the 14.5 Hz oscillation by a factor of 6

  1. Feedback Systems for Linear Colliders

    OpenAIRE

    Hendrickson, L.; Grossberg, P.; Himel, T.; Minty, M.; Phinney, N.; Raimondi, P.; Raubenheimer, T.; Shoaee, H.; Tenenbaum, P.

    2001-01-01

    Feedback systems are essential for stable operation of a linear collider, providing a cost-effective method for relaxing tight tolerances. In the Stanford Linear Collider (SLC), feedback controls beam parameters such as trajectory, energy, and intensity throughout the accelerator. A novel dithering optimization system which adjusts final focus parameters to maximize luminosity contributed to achieving record performance in the 1997-98 run. Performance limitations of the steering feedback have...

  2. LHC beam stability and feedback control

    Energy Technology Data Exchange (ETDEWEB)

    Steinhagen, Ralph

    2007-07-20

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a

  3. LHC beam stability and feedback control

    International Nuclear Information System (INIS)

    This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a proportional

  4. A unified approach to global and local beam position feedback

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) will implement both global and local beam position feedback systems to stabilize the particle and X-ray beams for the storage ring. The global feedback system uses 40 BPMs and 40 correctors per plane. Singular value decomposition (SVD) of the response matrix is used for closed orbit correction. The local feedback system uses two X-ray BPMS, two rf BPMS, and the four-magnet local bump to control the angle and displacement of the X-ray beam from a bending magnet or an insertion device. Both the global and local feedback systems are based on digital signal processing (DSP) running at 4-kHz sampling rate with a proportional, integral, and derivative (PID) control algorithm. In this paper, we will discuss resolution of the conflict among multiple local feedback systems due to local bump closure error and decoupling of the global and local feedback systems to maximize correction efficiency. In this scheme, the global feedback system absorbs the local bump closure error and the local feedback systems compensate for the effect of global feedback on the local beamlines. The required data sharing between the global and local feedback systems is done through the fiber-optically networked reflective memory

  5. Design of a transverse feedback system against multi bunch beam oscillation due to impedance in the KEK B-factory rings

    International Nuclear Information System (INIS)

    In future B-factories, many bunches will be circulated in their rings, and thus making the bunch spacing to become very short compared with that of the present collider machines. The impedance of the rings may cause many coupled bunch beam oscillations. One possibility to damp these multi-bunch oscillations is to install an active oscillation feedback damper system. This paper discusses the transverse feedback system. (author)

  6. Research on feedback system of synchrotron accelerator

    International Nuclear Information System (INIS)

    It is a very complex problem to use feedback control system in synchrotron accelerator. Some scientists design feedback control system to make high energy beam stable in synchrotron accelerator, but it is very rare to see theoretically analysis feedback system in synchrotron accelerator by using new concept of control model. One new feedback control model is a fresh idea to discuss the feedback system more deeply. A topic about feedback control system discussed here will be useful for synchrotron accelerator design and operation. It is an good idea for some scientists and technician to continue study. (authors)

  7. Fast Feedback System for CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    M.P. Chowdhary; G.A. Krafft; H. Shoaee; W.A. Watson III

    1995-10-01

    A fast feedback system based on concepts of modern control theory has been implemented in the CEBAF Control System to stabilize various machine parameters. The continuous wave operation of CEBAF requires that parameters such as beam energy and position are stabilized against fast fluctuations. The beam energy must be stabilized against fast gradient and phase fluctuations in the RF accelerating system. This fast feedback system currently operates at 60 Hz rate and is integrated with EPICS. The mathematical model of the system for various feedback loops is expressed in state space formalism. The design of control law and simulation of closed-loop system response is performed using MatlabTM and SimulinkTM. This paper describes the process of designing control algorithms, implementation of the fast feedback system and operational experience with this system at CEBAF. The performance of this feedback system, while operating at much higher rates with high closed loop gain, can be enhanced by continually performing on-line identification of the system from the input and output data. System identification is the process of developing or improving an analytically derived mathematical representation of a physical system using experimental data. The current status of this feature is presented.

  8. Policy Feedback System (PFS)

    Data.gov (United States)

    Social Security Administration — The Policy Feedback System (PFS) is a web application developed by the Office of Disability Policy Management Information (ODPMI) team that gathers empirical data...

  9. Longitudinal feedback system for PEP

    Energy Technology Data Exchange (ETDEWEB)

    Allen, M.A.; Cornacchia, M.; Millich, A.

    1979-02-01

    Whether the wide bandwidth longitudinal feedback system described in this paper is made to act on the individual modes in frequency domain or on the individual bunches in time domain, it represents a clean and efficient way of damping the longitudinal oscillations without influencing other beam parameters such as bunch shape or synchrotron frequency distribution. The frequency domain feedback presents the advantage of providing information on which modes are unstable and on their risetimes, which may be helpful in locating dangerous resonators in the ring.

  10. RHIC 10 Hz global orbit feedback system

    Energy Technology Data Exchange (ETDEWEB)

    Michnoff, R.; Arnold, L.; Carboni, L.; Cerniglia, P; Curcio, A.; DeSanto, L.; Folz, C.; Ho, C.; Hoff, L.; Hulsart, R.; Karl, R.; Luo, Y.; Liu, C.; MacKay, W.; Mahler, G.; Meng, W.; Mernick, K.; Minty, M.; Montag, C.; Olsen, R.; Piacentino, J.; Popken, P.; Przybylinski, R.; Ptitsyn, V.; Ritter, J.; Schoenfeld, R.; Thieberger, P.; Tuozzolo, J.; Weston, A.; White, J.; Ziminski, P.; Zimmerman, P.

    2011-03-28

    Vibrations of the cryogenic triplet magnets at the Relativistic Heavy Ion Collider (RHIC) are suspected to be causing the horizontal beam perturbations observed at frequencies around 10 Hz. Several solutions to counteract the effect have been considered in the past, including a local beam feedback system at each of the two experimental areas, reinforcing the magnet base support assembly, and a mechanical servo feedback system. However, the local feedback system was insufficient because perturbation amplitudes outside the experimental areas were still problematic, and the mechanical solutions are very expensive. A global 10 Hz orbit feedback system consisting of 36 beam position monitors (BPMs) and 12 small dedicated dipole corrector magnets in each of the two 3.8 km circumference counter-rotating rings has been developed and commissioned in February 2011. A description of the system architecture and results with beam will be discussed.

  11. Beam spill structure feedback test in HIRFL-CSR

    International Nuclear Information System (INIS)

    HIRFL-CSR is the post-acceleration system of the Heavy Ion Research Facility in Lanzhou and is composed of a double cooling storage ring and a radioactive beam line. The slow extraction beam from HIRFL-CSR is used in nuclear physics experiments and heavy ion therapy. 50 Hz ripple and harmonics are observed in beam spill. To improve the spill structure, the first set of control system consisting of fast Q-magnet and feedback device based FPGA is developed and installed in 2010. Spill structure feedback testing has also started. It is shown that the feedback structure has improved the spill structure, the 50 Hz ripple and its harmonics have been reduced

  12. The First Stage Modification Of The Servo-spill Feedback System For The Slow Resonant Beam Extraxtion From The Ihep 70 Gev Proton Synchrotron

    CERN Document Server

    Lapin, V V; Yaichkov, V A; Zyatkov, O V

    2004-01-01

    This paper presents the results of the first stage modification of the servo-spill feedback system for the slow resonant beam extraction from the IHEP 70 GeV proton synchrotron. The system has a time delay caused by resonance evolution. In the past the time delay was estimated equal from 1ms to 1.8ms, and the maximum open loop frequency cut-off was considered equal to a few tens Hz. The servo-spill feedback system was being used with the open loop frequency cut-off no more than 20Hz for many years. The qualitative analysis of the beam motion on the phase plot, the modeling of the system on the base of the Hamilton's equations numerical solution and the analysis of the experimental frequency responses indicated that the time delay value is noticeably less than former estimations. The first stage modification of the servo-spill feedback system has increased the open loop frequency cut-off at the beginning of extraction process up to approximately 300 Hz. The suppression coefficients of the beam intensity ripple...

  13. Generalized fast feedback system in the SLC

    International Nuclear Information System (INIS)

    A generalized fast feedback system has been developed to stabilize beams at various locations in the SLC. The system is designed to perform measurements and change actuator settings to control beam states such as position, angle and energy on a pulse to pulse basis. The software design is based on the state space formalism of digital control theory. The system is database-driven, facilitating the addition of new loops without requiring additional software. A communications system, KISNet, provides fast communications links between microprocessors for feedback loops which involve multiple micros. Feedback loops have been installed in seventeen locations throughout the SLC and have proven to be invaluable in stabilizing the machine

  14. Optimal centralized and decentralized velocity feedback control on a beam

    International Nuclear Information System (INIS)

    This paper considers the optimization of a velocity feedback controller with a collocated force actuator, to minimize the kinetic energy of a simply supported beam. If the beam is excited at a single location, the optimum feedback gain varies with the position of the control system. It is shown that this variation depends partly on the location of the control force relative to the exciting force. If a distributed excitation is assumed, that is random in both time and space, a unique optimum value of the feedback gain can be found for a given control location. The effect of the control location on performance and the optimal feedback gain can then be examined and is found to be limited provided the control locations are not close to the ends of the beam. The optimization can also be performed for a multichannel velocity feedback system. Both a centralized and a decentralized controller are considered. It is shown that the difference in performance between a centralized and a decentralized controller is small, unless the control locations are closely spaced. In this case the centralized controller effectively feeds back a moment proportional to angular velocity as well as a force proportional to a velocity. It is also shown that the optimal feedback gain can be approximated on the basis of a limited model and that similar results can be achieved

  15. Feedback control of quantum system

    Institute of Scientific and Technical Information of China (English)

    DONG Dao-yi; CHEN Zong-hai; ZHANG Chen-bin; CHEN Chun-lin

    2006-01-01

    Feedback is a significant strategy for the control of quantum system.Information acquisition is the greatest difficulty in quantum feedback applications.After discussing several basic methods for information acquisition,we review three kinds of quantum feedback control strategies:quantum feedback control with measurement,coherent quantum feedback,and quantum feedback control based on cloning and recognition.The first feedback strategy can effectively acquire information,but it destroys the coherence in feedback loop.On the contrary,coherent quantum feedback does not destroy the coherence,but the capability of information acquisition is limited.However,the third feedback scheme gives a compromise between information acquisition and measurement disturbance.

  16. Tracking control of a flexible beam by nonlinear boundary feedback

    Directory of Open Access Journals (Sweden)

    Bao-Zhu Guo

    1995-01-01

    Full Text Available This paper is concerned with tracking control of a dynamic model consisting of a flexible beam rotated by a motor in a horizontal plane at the one end and a tip body rigidly attached at the free end. The well-posedness of the closed loop systems considering the dissipative nonlinear boundary feedback is discussed and the asymptotic stability about difference energy of the hybrid system is also investigated.

  17. KEKB bunch feedback systems

    Energy Technology Data Exchange (ETDEWEB)

    Tobiyama, M.; Kikutani, E. [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    Design and the present status of the bunch by bunch feedback systems for KEKB rings are shown. The detection of the bunch oscillation are made with the phase detection for longitudinal plane, the AM/PM method for transverse plane. Two GHz component of the bunch signal which is extracted with an analog FIR filter is used for the detection. Hardware two-tap FIR filter systems to shift the phase of the oscillation by 90deg will be used for the longitudinal signal processing. The same system will be used with no filtering but with only digital delay for transverse system. The candidate for the kicker and the required maximum power are also estimated. (author)

  18. ATLAS Online Determination and Feedback of the LHC Beam Parameters

    CERN Document Server

    Cogan, J; The ATLAS collaboration; Strauss, E; Miller, E

    2011-01-01

    The High Level Trigger of the ATLAS experiment relies on the precise knowledge of the position, size and orientation of the luminous region produced by the LHC. Moreover, these parameters change significantly even during a single data taking run. We present the challenges, solutions and results for the online luminous region (beam spot) determination, and its monitoring and feedback system in ATLAS. The massively parallel calculation is performed on the trigger farm, where individual processors execute a dedicated algorithm that reconstructs event vertices from the proton-proton collision tracks seen in the silicon trackers. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. We describe the process by which a standalone application fetches and fits these distributions, extracting the parameters in real time. When the difference between the nominal and measured beam spot values satisfies threshold conditions, the parameters are published to close the feedback ...

  19. ATLAS Online Determination and Feedback of LHC Beam Parameters

    CERN Document Server

    Cogan, J G; The ATLAS collaboration; Bartoldus, R; Miller, D W

    2011-01-01

    The High Level Trigger of the ATLAS experiment relies on the precise knowledge of the position, size and orientation of the luminous region produced by the LHC. Moreover, these parameters change significantly even during a single data taking run. We present the challenges, solutions and results for the online luminous region (beam spot) determination, and its monitoring and feedback system in ATLAS. The massively parallel calculation is performed on the trigger farm, where individual processors execute a dedicated algorithm that reconstructs event vertices from the proton-proton collision tracks seen in the silicon trackers. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. We describe the process by which a standalone application fetches and fits these distributions, extracting the parameters in real time. When the difference between the nominal and measured beam spot values satisfies threshold conditions, the parameters are published to close the feedback ...

  20. Suppression of beam halo-chaos using nonlinear feedback discrete control method

    CERN Document Server

    Fang Jin Qing; Chen Guan Rong; Luo Xiao Shu; Weng Jia Qiang

    2002-01-01

    Based on nonlinear feedback control method, wavelet-based feedback controller as a especial nonlinear feedback function is designed for controlling beam halo-chaos in high-current accelerators of driven clean nuclear power system. PIC simulations show that suppression of beam halo-chaos are realized effectively after discrete control of wavelet-based feed-back is applied to five kinds of the initial proton beam distributions, respectively. The beam halo strength factor is quickly reduced to zero, and other statistical physical quantities of beam halo-chaos are more than doubly reduced. These performed PIC simulation results demonstrate that the developed methods are very effective for control of beam halo-chaos. Potential application of the beam halo-chaos control methods is discussed finally

  1. FEEDBACK REALIZATION OF HAMILTONIAN SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    CHENGDaizhan; XIZairong

    2002-01-01

    This paper investigates the relationship between state feedback and Hamiltonican realization.Firest,it is proved that a completely controllable linear system always has a state feedback state equation Hamiltonian realization.Necessary and sufficient conditions are obtained for it to have a Hamiltonian realization with natural output.Then some conditions for an affine nonlinear system to have a Hamiltonian realization are given.some conditions for an affine nonlinear system to have a Hamiltonian realization are given.For generalized outputs,the conditions of the feedback,keeping Hamiltonian,are discussed.Finally,the admissible feedback controls for generalized Hamiltonian systems are considered.

  2. TFTR plasma feedback systems

    International Nuclear Information System (INIS)

    The Tokamak Fusion Test Reactor employs feedback control systems for four plasma parameters, i.e. for plasma current, for plasma major radius, for plasma vertical position, and for plasma density. The plasma current is controlled by adjusting the rate of change of current in the Ohmic Heating (OH) coil system. Plasma current is continuously sensed by a Rogowski coil and its associated electronics; the error between it and a preprogrammed reference plasma current history is operated upon by a ''proportional-plusintegral-plus-derivative'' (PID) control algorithm and combined with various feedforward terms, to generate compensating commands to the phase-controlled thyristor rectifiers which drive current through the OH coils. The plasma position is controlled by adjusting the currents in Equilibrium Field and Horizontal Field coil systems, which respectively determine the vertical and radial external magnetic fields producing J X B forces on the plasma current. The plasma major radius position and vertical position, sensed by ''B /sub theta/ '' and ''B /sub rho/ '' magnetic flux pickup coils with their associated electronics, are controlled toward preprogrammed reference histories by allowing PID and feedforward control algorithms to generate commands to the EF and HF coil power supplies. Plasma density is controlled by adjusting the amount of gas injected into the vacuum vessel. Time-varying gains are used to combine lineaveraged plasma density measurements from a microwave interferometer plasma diagnostic system with vacuum vessel pressure measurements from ion gauges, with various other measurements, and with preprogrammed reference histories, to determine commands to piezoelectric gas injection valves

  3. FEEDBACK REALIZATION OF HAMILTONIAN SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    CHENG Daizhan; XI Zairong

    2002-01-01

    This paper investigates the relationship between state feedback and Hamiltonian realizatiou. First, it is proved that a completely controllable linear system always has a state feedback state equation Hamiltonian realization. Necessary and sufficient conditions are obtained for it to have a Hamiltonian realization with natural outpnt. Then some conditions for an affine nonlinear system to have a Hamiltonian realization arc given.For generalized outputs, the conditions of the feedback, keeping Hamiltonian, are discussed. Finally, the admissible feedback controls for generalized Hamiltonian systems are considered.

  4. PEP-II RF feedback system simulation

    Energy Technology Data Exchange (ETDEWEB)

    Tighe, R. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    A model containing the fundamental impedance of the PEP-II cavity along with the longitudinal beam dynamics and RF feedback system components is in use. It is prepared in a format allowing time-domain as well as frequency-domain analysis and full graphics capability. Matlab and Simulink are control system design and analysis programs (widely available) with many built-in tools. The model allows the use of compiled C-code modules for compute intensive portions. We desire to represent as nearly as possible the components of the feedback system including all delays, sample rates and applicable nonlinearities. (author)

  5. LHC Beam Stability and Feedback Control - Orbit and Energy -

    CERN Document Server

    Steinhagen, R J

    2007-01-01

    This report presents the stability and control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The LHC, presently being built at CERN, will store, accelerate and provide particle collisions with a maximum particle momentum of 7TeV/c and a nominal luminosity of L = 10^34 cm^−2s^−1. The presence of two beams, with both high intensity as well as high particle energies, requires excellent control of particle losses inside a superconducting environment, which will be provided by the LHC Cleaning and Machine Protection System. The performance and function of this and other systems depends critically on the stability of the beam and may eventually limit the LHC performance. Environmental and accelerator-inherent sources as well as failure of magnets and their power converters may perturb and reduce beam stability and may consequently lead to an increase of particle loss inside the cryogenic mass. In order to counteract these disturbances, c...

  6. Controlling Beam Halo-Chaos via Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; WENG Jia-Qiang; ZHU Lun-Wu; LUO Xiao-Shu

    2004-01-01

    The study of controlling high-current proton beam halo-chaos has become a key concerned issue for many important applications. In this paper, time-delayed feedback control method is proposed for beam halo-chaos. Particle in cell simulation results show that the method is very effective and has some advantages for high-current beam experiments and engineering.

  7. Experimental study of delayed positive feedback control for a flexible beam

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Recently, some researches indicate that positive feedback can benefit the control if appropriate time delay is intentionally introduced into control system. However, most work is theoretical one but few are experimental. This paper presents theoretical and experimental studies of delayed positive feedback control technique using a flexible beam as research object. The positive feedback weighting coefficient is designed by using the optimal control method. The available time delay is determined by analyzing ...

  8. Automatic steering of x-ray beams from NSLS insertion devices using closed orbit feedback

    International Nuclear Information System (INIS)

    By the middle of this year (1989), there will be five insertion devices installed in the NSLS X-ray electron storage ring. X-ray beams from these devices will be stabilized by local automatic steering systems to reduce beam motion at the end of the beamline. Both the position of the source and the direction of the radiation will be controlled using beam position feedback to the closed orbit. Another system will be installed to stabilize the electron orbit for the LEGS Compton backscattering experiment. Each feedback system will employ at least one X-ray beam position detector; some will also utilize rf electron beam position monitors. Analog hardware with a digital interface has been designed and will be installed in the near future. A totally digital realization of the feedback controller is under consideration. 6 refs., 6 figs

  9. ATLAS online determination and feedback of the LHC beam parameters

    International Nuclear Information System (INIS)

    The High Level Trigger of the ATLAS experiment relies on the precise knowledge of the position, size and orientation of the luminous region produced by the LHC. Moreover, these parameters change significantly even during a single data taking run. We present the challenges, solutions and results for the online luminous region (beam spot) determination, and its monitoring and feedback system in ATLAS. The massively parallel calculation is performed on the trigger farm, where individual processors execute a dedicated algorithm that reconstructs event vertices from the proton-proton collision tracks seen in the silicon trackers. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. We describe the process by which a standalone application fetches and fits these distributions, extracting the parameters in real time. When the difference between the nominal and measured beam spot values satisfies threshold conditions, the parameters are published to close the feedback loop. To achieve sharp time boundaries across the event stream that is triggered at rates of several kHz, a special set of data is injected into the event path via the Central Trigger Processor that signals the pending update to the trigger nodes. Finally, we describe the efficient near-simultaneous database access through a proxy fan-out tree, which allows thousands of nodes to fetch the same set of values in a fraction of a second. (authors)

  10. Feedback control of optical beam spatial profiles using thermal lensing

    CERN Document Server

    Liu, Zhanwei; Arain, Muzammil A; Williams, Luke; Mueller, Guido; Tanner, David B; Reitze, David H

    2013-01-01

    A method for active control of the spatial profile of a laser beam using adaptive thermal lensing is described. A segmented electrical heater was used to generate thermal gradients across a transmissive optical element, resulting in a controllable thermal lens. The segmented heater also allows the generation of cylindrical lenses, and provides the capability to steer the beam in both horizontal and vertical planes. Using this device as an actuator, a feedback control loop was developed to stabilize the beam size and position.

  11. Effect of horizontal fast electron beam position feedback on the performance of ESRF beamlines

    International Nuclear Information System (INIS)

    ESRF is a state of the art third generation synchrotron light source optimized to produce very bright and collimated hard X-ray beams using insertion devices. Instabilities of the electron beam, resulting in source point transverse displacements, spoil these outstanding beam qualities. At the beginning of operation a fast active feedback system was installed to damp the transverse motion of the electron beam in the vertical plane. Recently it became evident that also the relatively smaller horizontal instabilities may have specific detrimental effects on the operation of particularly sensitive beamlines. The dispersive XAS beamline (ID24) was the first to benefit from the activation of a local horizontal feedback. Optimized to perform time-resolved studies and high-pressure experiments, its operation was strongly perturbed. This paper briefly describes the work carried out to identify and solve these problems, presenting the outcome of the implementation of a fast orbit feedback on this beamline

  12. On boundary feedback stabilization of Timoshenko beam with rotor inertia at the tip

    Institute of Scientific and Technical Information of China (English)

    Qingxu YAN; Li WAN; Dexing FENG

    2004-01-01

    The feedback stabilization problem of a nonuniform Timoshenko beam system with rotor inertia at the tip of the beam is studied.First,as a special kind of linear boundary force feedback and moment control is applied to the beam's tip,the strict mathematical treatment,a suitable state Hilbert space is chosen,and the well-poseness of the corresponding closed loop system is proved by using the semigroup theory of bounded linear operators.Then the energy corresponding to the closed loop system is shown to be exponentially stable.Finally,in the special case of uniform beam,some sufficient and necessary conditions for the corresponding closed loop system to be asymptotically stable are derived.

  13. Simulation of Transient Beam-Feedback Interaction and Application to Extraction of CNGS Beam from the SPS

    CERN Document Server

    Vogel, E

    2004-01-01

    For present and future high energy proton accelerators, such as the LHC, transverse feedback systems play an essential role in supplying the physics experiments with high intensity beams at low emittances. We developed a simulation model to study the interaction between beam and transverse feedback system in detail, bunch-by-bunch and turn-by-turn, considering the real technical implementation of the latter. A numerical model is used as the non linear behaviour (saturation) and limited bandwidth of the feedback system, as well as the transient nature at injection and extraction, complicates the analysis. The model is applied to the practical case of the CNGS beam in the SPS accelerator. This beam will be ejected from the SPS in two batches causing residual oscillations by kicker ripples on the second batch. This second batch continues to circulate for 2167 turns after the first batch has been extracted and oscillations are planned to be damped by the feedback system. The model can be extended to examine trans...

  14. Commissioning of the APS real-time orbit feedback system

    International Nuclear Information System (INIS)

    A unified global and local closed-orbit feedback system has been implemented at the Advanced Photon Source in order to stabilize both particle and photon beams. Beam stability requirements in the band up to 50 Hz are 17 microm in the horizontal plane and 4.4 microm vertically. Orbit feedback algorithms are implemented digitally using multiple digital signal processors, with computing power distributed in 20 VME crates around the storage ring. Each crate communicates with all others via a fast reflective memory network. The system has access to 320 rf beam position monitors together with x-ray beam position monitors in both insertion device and bending magnet beamlines. Up to 317 corrector magnets are available to the system. The global system reduces horizontal rms beam motion at the x-ray source points by more than a factor of two in the frequency band from 10 mHz to 50 Hz

  15. Simulation of Transient Effects of Beam-Transverse Feedback Interaction with Application to the Extraction of the CNGS Beam from the SPS

    CERN Document Server

    Höfle, Wolfgang

    2005-01-01

    For existing and future high energy proton accelerators, transverse feedback systems play an essential role in supplying the physics experiments with high intensity beams at low emittances. We developed a simulation model to study the interaction between beam and transverse feedback system in detail, bunch-by-bunch and turn-by-turn, considering the technical implementation at the SPS [1]. A numerical model is used as the non linear behaviour (saturation) and limited bandwidth of the feedback system, as well as the transient nature at injection and extraction, complicates the analysis. The model is applied to the practical case of the CNGS beam [2] in the SPS accelerator. This beam will be ejected from the SPS in two batches causing residual oscillations by kicker ripples on the second batch. This second batch continues to circulate for 50 ms (about 2170 turns) after the first batch has been extracted and oscillations are planned to be damped by the feedback system.

  16. Interaction between beam control and rf feedback loops for high Q cavities an heavy beam loading. Revision A

    International Nuclear Information System (INIS)

    An open-loop state space model of all the major low-level rf feedback control loops is derived. The model has control and state variables for fast-cycling machines to apply modern multivariable feedback techniques. A condition is derived to know when exactly we can cross the boundaries between time-varying and time-invariant approaches for a fast-cycling machine like the Low Energy Booster (LEB). The conditions are dependent on the Q of the cavity and the rate at which the frequency changes with time. Apart from capturing the time-variant characteristics, the errors in the magnetic field are accounted in the model to study the effects on synchronization with the Medium Energy Booster (MEB). The control model is useful to study the effects on beam control due to heavy beam loading at high intensities, voltage transients just after injection especially due to time-varying voltages, instability thresholds created by the cavity tuning feedback system, cross coupling between feedback loops with and without direct rf feedback etc. As a special case we have shown that the model agrees with the well known Pedersen model derived for the CERN PS booster. As an application of the model we undertook a detailed study of the cross coupling between the loops by considering all of them at once for varying time, Q and beam intensities. A discussion of the method to identify the coupling is shown. At the end a summary of the identified loop interactions is presented

  17. Stabilization of Nonuniform Euler-Bernoulli Beam with Locally Distributed Feedbacks

    Institute of Scientific and Technical Information of China (English)

    Xian-bing CAO; Qing-xu YAN

    2012-01-01

    In this article,we study the stabilization problem of a nonuniform Euler-Bernoulli beam with locally distributed feedbacks.Firstly,using the semi-group theory,we establish the well-posedness of the associated closed loop system.Then by proving the uniqueness of the solution of a related ordinary differential equations,we derive the asymptotic stability of the closed loop system. Finally,by means of the piecewise frequency domain multiplier method,we prove that the corresponding closed loop system can be exponentially stabilized by only one of the two distributed feedback controls proposed in this paper.

  18. ROBUST POSITIONING OF LASER BEAMS USING PROPORTIONAL INTEGRAL DERIVATIVE AND BASED OBSERVER-FEEDBACK CONTROL

    Directory of Open Access Journals (Sweden)

    Kwabena A. Konadu

    2013-01-01

    Full Text Available High-precision positioning of laser beams has been a great challenge in industry due to inevitable existence of noise and disturbance. The work presented in this study addresses this problem by employing two different control strategies: Proportional Integral Derivative (PID control and state feedback control with an observer. The control strategies are intended to stabilize the position of a laser beam on a Position Sensing Device (PSD located on a Laser Beam Stabilization (or, laser beam system system. The laser beam system consists of a laser source, a Fast Steering Mirror (FSM, a PSD and a vibrating platform to generate active disturbance. The traditional PID controller is widely used in industry due to its satisfactory performance, various available tuning methods and relatively straightforward design processes. However, design of filters to obtain the derivative signal is challenging and can unexpectedly distort the dynamics of the system being controlled. As an alternative, use of an Observer-Based State Feedback (OBSF method is proposed and implemented. The state-space model of the laser beam system is utilized and an observer is applied to estimate the state of the system, since all the state variables cannot be measured directly. For observer design, eigenvalue assignment and optimal design methods are used and compared in terms of system performance. Also a comparative analysis between the PID and OBSF controllers is provided. Simulations and experimental results show that the OBSF controller rejects disturbance better and has a simpler design procedure.

  19. Multimedia Feedback Systems for Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Gladwell, S.; Gottlieb, E.J.; McDonald, M.J.; Slutter, C.L.

    1998-12-15

    The World Wide Web has become a key tool for information sharing. Engineers and scientists are finding that the web is especially suited to publishing the graphical, multi-layered information that is typical of their work. Web pages are easier to distribute than hardcopy. Web movies have become more accessible, in many offices, than videos. Good VRML viewing software, bundled with most new PCs, has sufficient power to support many engineering needs. In addition to publishing information science and engineering has an important tradition of peer and customer review. Reports, drawings and graphs are typically printed, distributed, reviewed, marked up, and returned to the author. Adding review comments to paper is easy. When, however, the information is in electronic form, this ease of review goes away. It's hard to write on videos. It's even harder to write comments on animated 3D models. These feedback limitations reduce the value of the information overall. Fortunately, the web can also be a useful tool for collecting peer and customer review information. When properly formed, web reports, movies, and 3D animations can be readily linked to review notes. This paper describes three multimedia feed-back systems that Sandia National Laboratories has developed to tap that potential. Each system allows people to make context-sensitive comments about specific web content and electronically ties the comments back to the web content being referenced. The fuel system ties comments to specific web pages, the second system ties the comments to specific frames of digital movies, and the third ties the comments to specific times and viewpoints within 3D animations. In addition to the technologies, this paper describes how they are being used to support intelligent machine systems design at Sandia.

  20. Applications of Feedback Control in Quantum Systems

    OpenAIRE

    Jacobs, Kurt

    2006-01-01

    We give an introduction to feedback control in quantum systems, as well as an overview of the variety of applications which have been explored to date. This introductory review is aimed primarily at control theorists unfamiliar with quantum mechanics, but should also be useful to quantum physicists interested in applications of feedback control. We explain how feedback in quantum systems differs from that in traditional classical systems, and how in certain cases the results from modern optim...

  1. A prototype fast feedback system for energy lock at CEBAF

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhary, M.; Krafft, G.A.; Shoaee, H.; Simrock, S.N.; Watson, W.A.

    1995-12-31

    The beam energy at CEBAF must be controlled accurately against phase and gradient fluctuations in RF cavities in order to achieve a 2.5 {times} 10{sup {minus}5} relative energy spread. A prototype fast feedback system based on the concepts of Modern Control Theory has been implemented in the CEBAF control system to function as an energy lock. Measurements performed during the pulsed mode operations indicate presence of noise components at 4 Hz and 12 Hz on beam energy. This fast feedback prototype operates at 60 Hz rate and is integrated with EPICS. This paper describes the implementation of the fast feedback prototype, and operational experience with this system at CEBAF. 5 refs., 3 figs.

  2. Survey of Digital Feedback Systems in High Current Storage Rings

    International Nuclear Information System (INIS)

    In the last decade demand for brightness in synchrotron light sources and luminosity in circular colliders led to construction of multiple high current storage rings. Many of these new machines require feedback systems to achieve design stored beam currents. In the same time frame the rapid advances in the technology of digital signal processing allowed the implementation of these complex feedback systems. In this paper I concentrate on three applications of feedback to storage rings: orbit control in light sources, coupled-bunch instability control, and low-level RF control. Each of these applications is challenging in areas of processing bandwidth, algorithm complexity, and control of time-varying beam and system dynamics. I will review existing implementations as well as comment on promising future directions

  3. Electron beam focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  4. Feedback system to stabilize accelerating field in the UNK

    International Nuclear Information System (INIS)

    To stabilize accelerating field in the UNK proton synchrotron, an HF feedback system is proposed with one-turn time delay and two loops of automatic voltage control having unequal gains. The system would handle a pair of crucial effects caused by the fundamental mode of the accelerating cavities: heavy transient beam loading, and strong dipole and quadrupole longitudinal instabilities of the beam. The beam-cavity coupling impedance near HF is shown to be split up by the feedback loops into a 2 x 2 matrix. Its elements are used to estimate the residual error of the voltage across the accelerating gap from its nominal, the instability driving impedances near HF, and the net current required to drive an HF amplifier. A new global parameters to outline technical contours of the system are evaluated. 8 refs., 8 figs

  5. ON FEEDBACK CONTROL OF DELAYED CHAOTIC SYSTEM

    Institute of Scientific and Technical Information of China (English)

    李丽香; 彭海朋; 卢辉斌; 关新平

    2001-01-01

    In this paper two different types of feedback control technique are discussed: the standard feedback control and the time-delay feedback control which have been successfully used in many control systems. In order to understand to what extent the two different types of control technique are useful in delayed chaotic systems, some analytic stabilization conditions for chaos control from the two types of control technique are derived based on Lyapunov stabilization arguments. Similarly, we discuss the tracking problem by applying the time-delay feedback control. Finally, numerical examples are provided.

  6. Advanced information feedback in intelligent traffic systems.

    Science.gov (United States)

    Wang, Wen-Xu; Wang, Bing-Hong; Zheng, Wen-Chen; Yin, Chuan-Yang; Zhou, Tao

    2005-12-01

    The optimal information feedback is very important to many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. As to traffic flow, a reasonable real-time information feedback can improve the urban traffic condition by providing route guidance. In this paper, the influence of a feedback strategy named congestion coefficient feedback strategy is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other two information feedback strategies, i.e., travel time and mean velocity. PMID:16486093

  7. Feedbacks in Human-Landscape Systems

    Science.gov (United States)

    Chin, Anne; Florsheim, Joan L.; Wohl, Ellen; Collins, Brian D.

    2014-01-01

    This article identifies key questions and challenges for geomorphologists in investigating coupled feedbacks in human-landscape systems. While feedbacks occur in the absence of human influences, they are also altered by human activity. Feedbacks are a key element to understanding human-influenced geomorphic systems in ways that extend our traditional approach of considering humans as unidirectional drivers of change. Feedbacks have been increasingly identified in Earth-environmental systems, with studies of coupled human-natural systems emphasizing ecological phenomena in producing emerging concepts for social-ecological systems. Enormous gaps or uncertainties in knowledge remain with respect to understanding impact-feedback loops within geomorphic systems with significant human alterations, where the impacted geomorphic systems in turn affect humans. Geomorphology should play an important role in public policy by identifying the many diffuse and subtle feedbacks of both local- and global-scale processes. This role is urgent, while time may still be available to mitigate the impacts that limit the sustainability of human societies. Challenges for geomorphology include identification of the often weak feedbacks that occur over varied time and space scales ranging from geologic time to single isolated events and very short time periods, the lack of available data linking impact with response, the identification of multiple thresholds that trigger feedback mechanisms, the varied tools and metrics needed to represent both physical and human processes, and the need to collaborate with social scientists with expertise in the human causes of geomorphic change, as well as the human responses to such change.

  8. Development of the orbit feedback system for the VSX ring

    International Nuclear Information System (INIS)

    An orbit feedback system will be installed in the VSX ring to stabilize the photon beam. The new COD correction method, the eigenvector method with constraints, is adopted for calculation of the steering-magnet currents. A computer simulation shows that the new method can tightly fix the beam positions at insertion devices, correcting the whole closed orbit globally with almost the same performance as the ordinary eigenvector method. A test VME unit including DSP and shared memory boards is being developed for the fast feedback control and its performance test shows that the total feedback time is less than 1 ms (875 μs) except for the network and VME-bus transfer times related to the shared memory board

  9. Energy feedback system for the SSRL Injector linac

    International Nuclear Information System (INIS)

    The SSRL Injector microwave gun, linac, and booster were commissioned last year. For efficient injection into the booster the linac beam energy must be stable to within about 1%. Unfortunately, fluctuations in the line voltage supplying the unregulated klystron modulators cause fluctuations in the linac beam energy, thus making the operation of the booster potentially very difficult. Without any corrections, the linac energy may drift by as much as one percent per minute or it may jump suddenly by one percent. Fortunately, the linac beam energy can be kept close to the desired value by using feedback on the low level controls of the klystrons feeding two of the linac sections. The energy of the linac is sampled at a beam position monitor (BPM) downstream of the first magnet following the linac. The feedback loop is closed using a low-pass filter that filters out noise from the BPM processing electronics. The feedback is implemented as a computer program (energy feedback) written in C for the SSRL Injector control system, and is robust against various fault conditions, as a result of the many changes and adjustments suggested by the commissioning team who are mentioned in the acknowledgements

  10. Beam alignment system

    International Nuclear Information System (INIS)

    A patent is claimed for the invention of a beam alignment system. The aim of the invention is the obtention of an accurate monitoring of the beam position and direction. It is of great interest in the nuclear industry. The invention can be applied in an infrared laser beam for welding operations. An auxiliar radiation source is incorporated to the device. The system's configuration allows a simultaneous and separated utilisation of two beams. The description and the design of the proposed system are provided

  11. Stability Analysis of Nonlinear Feedback Control Methods for Beam Halo-chaos

    Institute of Scientific and Technical Information of China (English)

    WANGZhong-sheng; FANGJin-qing; CHENGuan-rong

    2003-01-01

    Control of beam halo-chaos has been a more challenge subject in recent years, in which nonlinear feedback method for beam halo-chaos has been developed for control of beam halo-chaos in high-current proton linear accelerators. However, stability analysis of nonlinear feedback control methods for beam halo-chaos has still been an open and important topic in this field. In this letter.

  12. Prediction feedback in intelligent traffic systems

    CERN Document Server

    Chuan-Fei, Dong; Guan-Wen, Wang; Xiao-Yan, Sun; Bing-Hong, Wang

    2009-01-01

    The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. In this paper, we studied dynamics of traffic flow with real-time information provided and the influence of a feedback strategy named prediction feedback strategy is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  13. Augmenting Environmental Interaction in Audio Feedback Systems

    Directory of Open Access Journals (Sweden)

    Seunghun Kim

    2016-04-01

    Full Text Available Audio feedback is defined as a positive feedback of acoustic signals where an audio input and output form a loop, and may be utilized artistically. This article presents new context-based controls over audio feedback, leading to the generation of desired sonic behaviors by enriching the influence of existing acoustic information such as room response and ambient noise. This ecological approach to audio feedback emphasizes mutual sonic interaction between signal processing and the acoustic environment. Mappings from analyses of the received signal to signal-processing parameters are designed to emphasize this specificity as an aesthetic goal. Our feedback system presents four types of mappings: approximate analyses of room reverberation to tempo-scale characteristics, ambient noise to amplitude and two different approximations of resonances to timbre. These mappings are validated computationally and evaluated experimentally in different acoustic conditions.

  14. Feedbacks in human-landscape systems

    Science.gov (United States)

    Chin, Anne

    2015-04-01

    As human interactions with Earth systems intensify in the "Anthropocene", understanding the complex relationships among human activity, landscape change, and societal responses to those changes is increasingly important. Interdisciplinary research centered on the theme of "feedbacks" in human-landscape systems serves as a promising focus for unraveling these interactions. Deciphering interacting human-landscape feedbacks extends our traditional approach of considering humans as unidirectional drivers of change. Enormous challenges exist, however, in quantifying impact-feedback loops in landscapes with significant human alterations. This paper illustrates an example of human-landscape interactions following a wildfire in Colorado (USA) that elicited feedback responses. After the 2012 Waldo Canyon Fire, concerns for heightened flood potential and debris flows associated with post-fire hydrologic changes prompted local landowners to construct tall fences at the base of a burned watershed. These actions changed the sediment transport regime and promoted further landscape change and human responses in a positive feedback cycle. The interactions ultimately increase flood and sediment hazards, rather than dampening the effects of fire. A simple agent-based model, capable of integrating social and hydro-geomorphological data, demonstrates how such interacting impacts and feedbacks could be simulated. Challenges for fully capturing human-landscape feedback interactions include the identification of diffuse and subtle feedbacks at a range of scales, the availability of data linking impact with response, the identification of multiple thresholds that trigger feedback mechanisms, and the varied metrics and data needed to represent both the physical and human systems. By collaborating with social scientists with expertise in the human causes of landscape change, as well as the human responses to those changes, geoscientists could more fully recognize and anticipate the coupled

  15. Orbit correction algorithm for SSRF fast orbit feedback system

    Institute of Scientific and Technical Information of China (English)

    LIU Ming; YIN Chongxian; LIU Dekang

    2009-01-01

    A fast orbit feedback system is designed at SSRF to suppress beam orbit disturbance within sub-micron in the bandwidth up to 100 Hz.The SVD (Singular value decomposition) algorithm is applied to calculate the inverse response matrix in global orbit correction.The number of singular eigenvalues will influence orbit noise suppression and corrector strengths.The method to choose singular eigenvalue rejection threshold is studied in this paper,and the simulation and experiment results are also presented.

  16. A tracking system with space virtual feedback

    Institute of Scientific and Technical Information of China (English)

    Zheng MAO; Xiaojun QU; Fuling WEI; Yali WANG

    2008-01-01

    In this paper,a tracking system with space virtual feedback(SVF)is presented.The whole tracking system is closed by the space virtual feedback line that is the line of sight(LOS),but the parts in the system,such as the tracking subsystem and the servo subsystem.are in the state of open-loop.Because the SVF tracking model is used.the correcting loops can be removed in this system architecture.So the tracking speed and accuracy of the system are greatly improved.

  17. Real time global orbit feedback system

    International Nuclear Information System (INIS)

    Stability of the electron orbit is essential for the utilization of a low emittance storage ring as high brightness radiation source. For an individual user, the required orbit stability can be achieved by a local bump feedback system. However, to install local bump feedback systems for every beamline is both costly and impractical. The coupling between different local bumps may introduce instability, and there may not be enough space for the large number of trim coils required. Here the authors discuss an approach for improving the stability of the closed orbit, by implementing a feedback system based upon harmonic analysis of the orbit movements and the correction magnetic fields. This harmonic feedback system corrects the Fourier components of the orbit nearest to the betatron tune, an approach which yields an orbit whose stability is sufficient for most experiments. The needs of the experiments requiring the tightest orbit tolerances can still be dealt with by additional local orbit feedback systems. Harmonic orbit correction is an effective technique for eliminating global orbit distortion in storage rings resulting from inevitable magnetic field errors distributed around the ring. The their knowledge, this approach has not previously been applied dynamically to eliminate orbit fluctuations arising from time varying magnetic field errors. They have developed a harmonic feedback system which is implemented on a real time basis using relatively simple electronics. The Fourier analysis is done by a simple linear analog network. The input voltages are proportional to the orbit displacements at the detectors, and in real time the output voltages are proportional to the desired Fourier harmonic coefficients. The feedback does not force the displacement to be zero at the detectors, but forces the coefficients of a few harmonics nearest the betatron tune to vanish

  18. Adaptive feedback linearization of nonlinear SISO systems

    Czech Academy of Sciences Publication Activity Database

    Gonzales, R. I.; Duarte-Mermoud, M. A.; Zagalak, Petr

    New Haven : Yale University, 2003, s. 160-169. [Workshop on Adaptive and Learning Systems /12./. Yale (US), 28.05.2003-30.05.2003] R&D Projects: GA ČR GA102/02/0204 Institutional research plan: CEZ:AV0Z1075907 Keywords : adaptive linearization * nonlinear systems * feedback linearization Subject RIV: BC - Control Systems Theory

  19. Simulation and analysis of rf feedback systems on the SLC damping rings

    International Nuclear Information System (INIS)

    The rf system of the SLC Damping Rings has evolved since tighter tolerances on beam stability are encountered as beam intensities are increased. There are now many feedback systems controlling the phase and amplitude of the rf, the phase of the beam, and the tune of the cavity. The bandwidths of the feedback loops range from several MHz to compensate for beam loading to a few Hz for the cavity tuners. To improve our understanding of the interaction of these loops and verify the expected behavior, we have simulated their behavior using computer models. A description of the models and the first results are discussed

  20. Mimicking the cochlear amplifier in a cantilever beam using nonlinear velocity feedback control

    International Nuclear Information System (INIS)

    The mammalian cochlea exhibits a nonlinear amplification which allows mammals to detect a large range of sound pressure levels while maintaining high frequency sensitivity. This work seeks to mimic the cochlea’s nonlinear amplification in a mechanical system. A nonlinear, velocity-based feedback control law is applied to a cantilever beam with piezoelectric actuators. The control law reduces the linear viscous damping of the system while introducing a cubic damping term. The result is a system which is positioned close to a Hopf bifurcation. Modelling and experimental results show that the beam with this control law undergoes a one-third amplitude scaling near the resonance frequency and an amplitude-dependent bandwidth. Both behaviors are characteristic of data obtained from the mammalian cochlea. This work could provide insight on the biological cochlea while producing bio-inspired sensors with a large dynamic range and sharp frequency sensitivity. (papers)

  1. Developing 360 degree feedback system for KINS

    Energy Technology Data Exchange (ETDEWEB)

    Han, In Soo; Cheon, B. M.; Kim, T. H.; Ryu, J. H. [Chungman National Univ., Daejeon (Korea, Republic of)

    2003-12-15

    This project aims to investigate the feasibility of a 360 degree feedback systems for KINS and to design guiding rules and structures in implementing that systems. Literature survey, environmental analysis and questionnaire survey were made to ensure that 360 degree feedback is the right tool to improve performance in KINS. That review leads to conclusion that more readiness and careful feasibility review are needed before implementation of 360 degree feedback in KINS. Further the project suggests some guiding rules that can be helpful for successful implementation of that system in KINS. Those include : start with development, experiment with one department, tie it to a clear organization's goal, train everyone involve, make sure to try that system in an atmosphere of trust.

  2. Developing 360 degree feedback system for KINS

    International Nuclear Information System (INIS)

    This project aims to investigate the feasibility of a 360 degree feedback systems for KINS and to design guiding rules and structures in implementing that systems. Literature survey, environmental analysis and questionnaire survey were made to ensure that 360 degree feedback is the right tool to improve performance in KINS. That review leads to conclusion that more readiness and careful feasibility review are needed before implementation of 360 degree feedback in KINS. Further the project suggests some guiding rules that can be helpful for successful implementation of that system in KINS. Those include : start with development, experiment with one department, tie it to a clear organization's goal, train everyone involve, make sure to try that system in an atmosphere of trust

  3. Stability Analysis of Some Nonlinear Feedback Control Methods for Beam Halo-Chaos Suppression

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; WANG Zhong-Sheng; CHEN Guan-Rong

    2004-01-01

    Control of beam halo-chaos has been a very challenging subject for research in recent years, in which some nonlinear feedback methods have been developed for suppression of beam halo-chaos in high-current proton linear accelerators. However, stability analysis of such successful nonlinear feedback control methods has not yet been rigorously carried out, which remains an important open topic in the field. In this letter, we present a rigorous mathematical analysis of several nonlinear feedback control methods that are applied to control beam halo-chaos with great success on simulations.

  4. Stability Analysis of Some Nonlinear Feedback Control Methods for Beam Halo-ChaosSuppression

    Institute of Scientific and Technical Information of China (English)

    FANGJin-Qing; WANGZhong-Sheng; CHENGuan-Rong

    2004-01-01

    Control of beam halo-chaos has been a very challenging subject for research in recent years, in which some nonlinear feedback methods have been developed for suppression of beam halo-chaos in high-current proton linear accelerators. However, stability analysis of such successful nonlinear feedback control methods has not yet been rigorously carried out, which remains an important open topic in the field. In this letter, we present a rigorous mathematical analysis of several nonlinear feedback control methods that are applied to control beam halo-chaos with great success on simulations.

  5. Phase and amplitude feedback control system for the Los Alamos free-electron laser

    International Nuclear Information System (INIS)

    Phase and amplitude feedback control systems for the Los Alamos free-electron laser (FEL) are described. Beam-driven voltages are very high in the buncher cavity because the electron gun is pulsed at the fifth subharmonic of the buncher resonant frequency. The high beam loading necessitated a novel feedback and drive configuration for the buncher. A compensation cirucit has been added to the gun/driver system to reduce observed drift. Extremely small variations in the accelerator gradients had dramatic effects on the laser output power. These problems and how they were solved are described and plans for improvements in the feedback control system are discussed. 5 refs., 7 figs

  6. Development of Adaptive Feedback Control System of Both Spatial and Temporal Beam Shaping for UV-Laser Light Source for RF Gun

    CERN Document Server

    Tomizawa, H; Dewa, H; Hanaki, H; Kobayashi, T; Mizuno, A; Suzuki, S; Taniuchi, T; Yanagida, K

    2004-01-01

    The ideal spatial and temporal profiles of a shot-by-shot single laser pulse are essential to suppress the emittance growth of the electron beam from a photo-cathode rf gun. We have been developing highly qualified UV-laser pulse as a light source of the rf gun for an injector candidate of future light sources. The gun cavity is a single-cell pillbox, and the copper inner wall is used as a photo cathode. The electron beam was accelerated up to 4.1 MeV at the maximum electric field on the cathode surface of 175 MV/m. For emittance compensation, two solenoid coils were used. As the first test run, with a microlens array as a simple spatial shaper, we obtained a minimum emittance value of 2 π·mm·mrad with a beam energy of 3.1 MeV, holding its charge to 0.1 nC/bunch. In the next test run, we prepared a deformable mirror for spatial shaping, and a spatial light modulator based on fused-silica plates for temporal shaping. We applied the both adaptive optics to automatically shape the bot...

  7. Diversity in School Performance Feedback Systems

    Science.gov (United States)

    Verhaeghe, Goedele; Schildkamp, Kim; Luyten, Hans; Valcke, Martin

    2015-01-01

    As data-based decision making is receiving increased attention in education, more and more school performance feedback systems (SPFSs) are being developed and used worldwide. These systems provide schools with data on their functioning. However, little research is available on the characteristics of the different SPFSs. Therefore, this study…

  8. Exact stability chart of an elastic beam subjected to delayed feedback

    Science.gov (United States)

    Zhang, Li; Stepan, Gabor

    2016-04-01

    The stability of an elastic beam is studied when the beam is subjected to a longitudinal force governed by a feedback loop. The setup of the simplified mechanical model is motivated by a basic problem of electroacoustics. The corresponding governing equation is the 1D wave equation with delayed boundary conditions. By means of the D'Alembert solution, the system can be transformed into a delay differential equation of neutral type that includes two time delays. The intricate stability chart is constructed analytically in the parameter plane of the gain parameter and the ratio of the time delays. The complete chart extends the numerical results of the literature, while it also draws attention to the numerical difficulties of finite degree of freedom approximations and to the extreme sensitivity of the dynamics with respect to the time delay parameters of the system.

  9. Novel Reduced-Feedback Wireless Communication Systems

    KAUST Repository

    Shaqfeh, Mohammad Obaidah

    2011-11-20

    Modern communication systems apply channel-aware adaptive transmission techniques and dynamic resource allocation in order to exploit the peak conditions of the fading wireless links and to enable significant performance gains. However, conveying the channel state information among the users’ mobile terminals into the access points of the network consumes a significant portion of the scarce air-link resources and depletes the battery resources of the mobile terminals rapidly. Despite its evident drawbacks, the channel information feedback cannot be eliminated in modern wireless networks because blind communication technologies cannot support the ever-increasing transmission rates and high quality of experience demands of current ubiquitous services. Developing new transmission technologies with reduced-feedback requirements is sought. Network operators will benefit from releasing the bandwidth resources reserved for the feedback communications and the clients will enjoy the extended battery life of their mobile devices. The main technical challenge is to preserve the prospected transmission rates over the network despite decreasing the channel information feedback significantly. This is a noteworthy research theme especially that there is no mature theory for feedback communication in the existing literature despite the growing number of publications about the topic in the last few years. More research efforts are needed to characterize the trade-off between the achievable rate and the required channel information and to design new reduced-feedback schemes that can be flexibly controlled based on the operator preferences. Such schemes can be then introduced into the standardization bodies for consideration in next generation broadband systems. We have recently contributed to this field and published several journal and conference papers. We are the pioneers to propose a novel reduced-feedback opportunistic scheduling scheme that combines many desired features

  10. ROBUST POSITIONING OF LASER BEAMS USING PROPORTIONAL INTEGRAL DERIVATIVE AND BASED OBSERVER-FEEDBACK CONTROL

    OpenAIRE

    Kwabena A. Konadu; Sun Yi; Wonchang Choi; Taher Abu-Lebdeh

    2013-01-01

    High-precision positioning of laser beams has been a great challenge in industry due to inevitable existence of noise and disturbance. The work presented in this study addresses this problem by employing two different control strategies: Proportional Integral Derivative (PID) control and state feedback control with an observer. The control strategies are intended to stabilize the position of a laser beam on a Position Sensing Device (PSD) located on a Laser Beam Stabilization (or, laser beam ...

  11. Distributed delays stabilize neural feedback systems

    CERN Document Server

    Meyer, Ulrike; Chakrabarty, Saurish; Brandt, Sebastian F; Luksch, Harald; Wessel, Ralf

    2007-01-01

    We consider the effect of distributed delays in neural feedback systems. The avian optic tectum is reciprocally connected with the nucleus isthmi. Extracellular stimulation combined with intracellular recordings reveal a range of signal delays from 4 to 9 ms between isthmotectal elements. This observation together with prior mathematical analysis concerning the influence of a delay distribution on system dynamics raises the question whether a broad delay distribution can impact the dynamics of neural feedback loops. For a system of reciprocally connected model neurons, we found that distributed delays enhance system stability in the following sense. With increased distribution of delays, the system converges faster to a fixed point and converges slower toward a limit cycle. Further, the introduction of distributed delays leads to an increased range of the average delay value for which the system's equilibrium point is stable. The enhancement of stability with increasing delay distribution is caused by the int...

  12. Active vibration control of clamped beams using positive position feedback controllers with moment pair

    International Nuclear Information System (INIS)

    This paper investigates the active vibration control of clamp beams using positive position feedback (PPF) controllers with a sensor/ moment pair actuator. The sensor/moment pair actuator which is the non-collocated configuration leads to instability of the control system when using the direct velocity feedback (DVFB) control. To alleviate the instability problem, a PPF controller is considered in this paper. A parametric study of the control system with PPF controller is first conducted to characterize the effects of the design parameters (gain and damping ratio in this paper) on the stability and performance. The gain of the controller is found to affect only the relative stability. Increasing the damping ratio of the controller slightly improves the stability condition while the performance gets worse. In addition, the higher mode tuned PPF controller affects the system response at the lower modes significantly. Based on the characteristics of PPF controllers, a multi-mode controllable SISO PPF controller is then considered and tuned to different modes (in this case, three lowest modes) numerically and experimentally. The multi-mode PPF controller can be achieved to have a high gain margin. Moreover, it reduces the vibration of the beam significantly. The vibration levels at the tuned modes are reduced by about 11 dB

  13. Robust synchronization of chaotic systems via feedback

    Energy Technology Data Exchange (ETDEWEB)

    Femat, Ricardo [IPICYT, San Luis Potosi (Mexico). Dept. de Matematicas Aplicadas; Solis-Perales, Gualberto [Universidad de Guadalajara, Centro Univ. de Ciencias Exactas e Ingenierias (Mexico). Div. de Electronica y Computacion

    2008-07-01

    This volume includes the results derived during last ten years about both suppression and synchronization of chaotic -continuous time- systems. Along this time, the concept was to study how the intrinsic properties of dynamical systems can be exploited to suppress and to synchronize the chaotic behaviour and what synchronization phenomena can be found under feedback interconnection. A compilation of these findings is described in this book. This book shows a perspective on synchronization of chaotic systems. (orig.)

  14. Beam systems without failures - What can be done?

    International Nuclear Information System (INIS)

    The beam dumps at 3.5 TeV triggered by interlocks not related to the magnet powering are discussed. This concerns the systems like the RF, the transverse feedbacks, beam instrumentation, beam dumping system, collimators and control systems. An analysis of the reasons of these dumps is presented together with a possible strategy to mitigate the effect of these failures. It is very important to notice that no system has been identified to have any structural problem

  15. Target and orbit feedback simulations of a muSR beam line at BNL

    Energy Technology Data Exchange (ETDEWEB)

    MacKay, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2015-07-28

    Well-polarized positive surface muons are a tool to measure the magnetic properties of materials since the precession rate of the spin can be determined from the observation of the positron directions when the muons decay. For a dc beam an ideal µSR flux for surface µ+ should be about 40 kHz/mm2. In this report we show how this flux could be achieved in a beam line using the AGS complex at BNL for a source of protons. We also determined that an orbit feedback system with a pair of thin silicon position monitors and kickers would miss the desired flux by at least an order of magnitude, even with perfect time resolution and no multiple scattering.

  16. Development of beam current control system in RF-knockout slow extraction

    Energy Technology Data Exchange (ETDEWEB)

    Mizushima, K., E-mail: mizshima@nirs.go.jp [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan); Graduate School of Science and Technology, Chiba University, Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Sato, S.; Shirai, T.; Furukawa, T.; Katagiri, K.; Takeshita, E.; Iwata, Y.; Himukai, T.; Noda, K. [Department of Accelerator and Medical Physics, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2011-12-15

    A raster scanning method has been developed for cancer therapy at NIRS-HIMAC. This method requires a high-accuracy beam current control and fast beam-on/off switching. We have developed a feedback control system of the beam current with the RF-knockout slow extraction method. The system has allowed a stable response to beam-on/off switching using a feedback control delay function with a beam-current ripple of 7%.

  17. ITER neutral beam system

    International Nuclear Information System (INIS)

    The Neutral Beam (NB) system for the International Thermonuclear Experimental Reactor (ITER) has reached a high degree of integration with the tokamak and with the rest of the plant. Operational requirements and maintainability have been considered in the design. The paper considers the integration with the tokamak, discusses design improvements which appear necessary and finally notes R and D progress in key areas. (author)

  18. Electron beam processing system

    International Nuclear Information System (INIS)

    Electron beam Processing Systems (EPS) are used as useful and powerful tools in many industrial application fields such as the production of cross-linked wire, rubber tire, heat shrinkable film and tubing, curing, degradation of polymers, sterilization and environmental application. In this paper, the feature and application fields, the selection of machine ratings and safety measures of EPS will be described. (author)

  19. Terrestrial biogeochemical feedbacks in the climate system

    Science.gov (United States)

    Arneth, A.; Harrison, S. P.; Zaehle, S.; Tsigaridis, K.; Menon, S.; Bartlein, P. J.; Feichter, J.; Korhola, A.; Kulmala, M.; O'Donnell, D.; Schurgers, G.; Sorvari, S.; Vesala, T.

    2010-08-01

    The terrestrial biosphere is a key regulator of atmospheric chemistry and climate. During past periods of climate change, vegetation cover and interactions between the terrestrial biosphere and atmosphere changed within decades. Modern observations show a similar responsiveness of terrestrial biogeochemistry to anthropogenically forced climate change and air pollution. Although interactions between the carbon cycle and climate have been a central focus, other biogeochemical feedbacks could be as important in modulating future climate change. Total positive radiative forcings resulting from feedbacks between the terrestrial biosphere and the atmosphere are estimated to reach up to 0.9 or 1.5 W m-2 K-1 towards the end of the twenty-first century, depending on the extent to which interactions with the nitrogen cycle stimulate or limit carbon sequestration. This substantially reduces and potentially even eliminates the cooling effect owing to carbon dioxide fertilization of the terrestrial biota. The overall magnitude of the biogeochemical feedbacks could potentially be similar to that of feedbacks in the physical climate system, but there are large uncertainties in the magnitude of individual estimates and in accounting for synergies between these effects.

  20. Monitoring Digital Closed-Loop Feedback Systems

    Science.gov (United States)

    Katz, Richard; Kleyner, Igor

    2011-01-01

    A technique of monitoring digital closed-loop feedback systems has been conceived. The basic idea is to obtain information on the performances of closed-loop feedback circuits in such systems to aid in the determination of the functionality and integrity of the circuits and of performance margins. The need for this technique arises as follows: Some modern digital systems include feedback circuits that enable other circuits to perform with precision and are tolerant of changes in environment and the device s parameters. For example, in a precision timing circuit, it is desirable to make the circuit insensitive to variability as a result of the manufacture of circuit components and to the effects of temperature, voltage, radiation, and aging. However, such a design can also result in masking the indications of damaged and/or deteriorating components. The present technique incorporates test circuitry and associated engineering-telemetry circuitry into an embedded system to monitor the closed-loop feedback circuits, using spare gates that are often available in field programmable gate arrays (FPGAs). This technique enables a test engineer to determine the amount of performance margin in the system, detect out of family circuit performance, and determine one or more trend(s) in the performance of the system. In one system to which the technique has been applied, an ultra-stable oscillator is used as a reference for internal adjustment of 12 time-to-digital converters (TDCs). The feedback circuit produces a pulse-width-modulated signal that is fed as a control input into an amplifier, which controls the circuit s operating voltage. If the circuit s gates are determined to be operating too slowly or rapidly when their timing is compared with that of the reference signal, then the pulse width increases or decreases, respectively, thereby commanding the amplifier to increase or reduce, respectively, its output level, and "adjust" the speed of the circuits. The nominal

  1. Beam Instrumentation Using BPM System of the SPring-8 Linac

    CERN Document Server

    Yanagida, K; Dewa, H; Hanaki, H; Kobayashi, T; Mizuno, A; Suzuki, S; Taniuchi, T; Tomizawa, H

    2004-01-01

    A beam position monitor (BPM) system of the SPring-8 linac has been operated since 2002. The following upgrade programs have been carried out during this period: The BPMs were installed in the linac's dispersive sections. A synchronized accumulation of beam position data into the database system started. A feedback control of steering magnets for beam position stabilization has been under development. In this conference the authors report a performance of the BPM system, and discuss its usefulness for beam diagnostics, machine diagnostics and beam stabilization.

  2. Assessing biosphere feedbacks on Earth System Processes

    Science.gov (United States)

    McElwain, Jennifer

    2016-04-01

    The evolution and ecology of plant life has been shaped by the direct and indirect influence of plate tectonics. Climatic change and environmental upheaval associated with the emplacement of large igneous provinces have triggered biosphere level ecological change, physiological modification and pulses of both extinction and origination. This talk will investigate the influence of large scale changes in atmospheric composition on plant ecophysiology at key intervals of the Phanerozoic. Furthermore, I will assess the extent to which plant ecophysiological response can in turn feedback on earth system processes such as the global hydrological cycle and biogeochemical cycling of nitrogen and carbon. Palaeo-atmosphere simulation experiments, palaeobotanical data and recent historical (last 50 years) data-model comparison will be used to address the extent to which plant physiological responses to atmospheric CO2 can modulate global climate change via biosphere level feedback.

  3. Optimal Feedback Systems with Analogue Adaptive Transmitters

    CERN Document Server

    Platonov, Anatoliy

    2010-01-01

    The paper presents original approach to concurrent optimization of the transmitting and receiving parts of adaptive communication systems (CS) with feedback channels. The results of research show a possibility and the way of designing the systems transmitting the signals with a bit rate equal to the capacity of the forward channel under given bit-error rate (BER). The results of work can be used for design of different classes of high-efficient low energy/size/cost CS, as well as allow further development and extension.

  4. Adaptive feedback beam shaping of the CO2 welding laser

    Czech Academy of Sciences Publication Activity Database

    Jedlička, Petr; Mrňa, L.; Šarbort, M.; Řeřucha, Šimon

    Bellingham: SPIE, 2010, 77890V: 1-8. ISBN 978-0-8194-8285-3. [Laser Beam Shaping XI. San Diego (US), 02.08.2010] R&D Projects: GA MPO 2A-3TP1/113 Institutional research plan: CEZ:AV0Z20650511 Keywords : laser beam welding * adaptive optics * laser welding control * light emission monitoring Subject RIV: BH - Optics, Masers, Lasers

  5. Control of beam halo-chaos by delayed self-controlling feedback

    CERN Document Server

    Zhu Lun Wu; Gao Yuan; Fang Jin Qing

    2002-01-01

    The delayed self-controlling feedback method is used to control beam halo-chaos in high-intensity accelerator effectively under five different initial distributions of protons. A brief theoretic analysis is presented. This method, considering its linear controller and weak feedback, has the advantage in technology realizability and cost saving. It cna be a good reference in the application to high-intensity accelerators

  6. Simulations of the TESLA Linear Collider with a Fast Feedback System

    CERN Document Server

    Schulte, Daniel; White, G

    2003-01-01

    The tolerances on the beams as they collide at the interaction point of the TESLA linear collider are very tight due to the nano-metre scale final vertical bunch spot sizes. Ground motion causes the beams to increase in emittance and drift out of collision leading to dramatic degradation of luminosity performance. To combat this, both slow orbit and fast intra-train feedback systems will be used. The design of these feedback systems depends critically on how component misalignment effects the beam throughout the whole accelerator. A simulation has been set up to study in detail the accelerator performance under such conditions by merging the codes of PLACET, MERLIN and GUINEA-PIG together with Simulink code to model feedback systems, all under a Matlab environment.

  7. Synchronization between two different chaotic systems with nonlinear feedback control

    Institute of Scientific and Technical Information of China (English)

    Lü Ling; Guo Zhi-An; Zhang Chao

    2007-01-01

    This paper presents chaos synchronization between two different chaotic systems by using a nonlinear controller, in which the nonlinear functions of the system are used as a nonlinear feedback term. The feedback controller is designed on the basis of stability theory, and the area of feedback gain is determined. The artificial simulation results show that this control method is commendably effective and feasible.

  8. Velocity Feedback Control of a Mechatronics System

    Directory of Open Access Journals (Sweden)

    Ayman A. Aly

    2013-07-01

    Full Text Available Increasing demands in performance and quality make drive systems fundamental parts in the progressive automation of industrial process. The analysis and design of Mechatronics systems are often based on linear or linearized models which may not accurately represent the servo system characteristics when the system is subject to inputs of large amplitude. The impact of the nonlinearities of the dynamic system and its stability needs to be clarified.The objective of this paper is to present a nonlinear mathematical model which allows studying and analysis of the dynamic characteristic of an electro hydraulic position control servo. The angular displacement response of motor shaft due to large amplitude step input is obtained by applying velocity feedback control strategy. The simulation results are found to be in agreement with the experimental data that were generated under similar conditions.

  9. Simulation of the ALS longitudinal multibunch feedback system

    International Nuclear Information System (INIS)

    Longitudinal coupled bunch growth rates in the Advanced Light Source (ALS), a 1.5 GeV electron storage ring for producing synchrotron radiation, indicate the need for damping via a feedback (FB) system. The design of the system is based on the proposed PEP-II longitudinal FB system which uses a digital filter to provide the required phase and amplitude response. We report the results of a detailed computer simulation of the FB system including single particle longitudinal beam dynamics, measured RF cavity fundamental and higher order modes, and response of major FB components such as the power amplifier and kicker. The simulation addresses issues such as required FB power and gain, noise, digital filter effects, and varying initial bunch conditions

  10. System analysis of force feedback microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Mario S. [CFMC/Dep. de Física, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Costa, Luca [European Synchrotron Radiation Facility, 6 rue Jules Horowitz BP 220, 38043 Grenoble Cedex (France); Université Joseph Fourier BP 53, 38041 Grenoble Cedex 9 (France); Chevrier, Joël [European Synchrotron Radiation Facility, 6 rue Jules Horowitz BP 220, 38043 Grenoble Cedex (France); Université Grenoble Alpes, Inst NEEL, F-38042 Grenoble (France); CNRS, Inst NEEL, F-38042 Grenoble (France); Comin, Fabio [European Synchrotron Radiation Facility, 6 rue Jules Horowitz BP 220, 38043 Grenoble Cedex (France)

    2014-02-07

    It was shown recently that the Force Feedback Microscope (FFM) can avoid the jump-to-contact in Atomic force Microscopy even when the cantilevers used are very soft, thus increasing force resolution. In this letter, we explore theoretical aspects of the associated real time control of the tip position. We take into account lever parameters such as the lever characteristics in its environment, spring constant, mass, dissipation coefficient, and the operating conditions such as controller gains and interaction force. We show how the controller parameters are determined so that the FFM functions at its best and estimate the bandwidth of the system under these conditions.

  11. System analysis of force feedback microscopy

    Science.gov (United States)

    Rodrigues, Mario S.; Costa, Luca; Chevrier, Joël; Comin, Fabio

    2014-02-01

    It was shown recently that the Force Feedback Microscope (FFM) can avoid the jump-to-contact in Atomic force Microscopy even when the cantilevers used are very soft, thus increasing force resolution. In this letter, we explore theoretical aspects of the associated real time control of the tip position. We take into account lever parameters such as the lever characteristics in its environment, spring constant, mass, dissipation coefficient, and the operating conditions such as controller gains and interaction force. We show how the controller parameters are determined so that the FFM functions at its best and estimate the bandwidth of the system under these conditions.

  12. Computing using delayed feedback systems: towards photonics

    Science.gov (United States)

    Appeltant, L.; Soriano, M. C.; Van der Sande, G.; Danckaert, J.; Massar, S.; Dambre, J.; Schrauwen, B.; Mirasso, C. R.; Fischer, I.

    2012-06-01

    Reservoir computing has recently been introduced as a new paradigm in the eld of machine learning. It is based on the dynamical properties of a network of randomly connected nodes or neurons and shows to be very promising to solve complex classication problems in a computationally ecient way. The key idea is that an input generates nonlinearly transient behavior rendering transient reservoir states suitable for linear classication. Our goal is to study up to which extent systems with delay, and especially photonic systems, can be used as reservoirs. Recently an new architecture has been proposed1 , based on a single nonlinear node with delayed feedback. An electronic1 and an opto-electronic implementation2, 3 have been demonstrated and both have proven to be very successful in terms of performance. This simple conguration, which replaces an entire network of randomly connected nonlinear nodes with one single hardware node and a delay line, is signicantly easier to implement experimentally. It is no longer necessary to construct an entire network of hundreds or even thousands of circuits, each one representing a node. With this approach one node and a delay line suce to construct a computational unit. In this manuscript, we present a further investigation of the properties of delayed feedback congurations used as a reservoir. Instead of quantifying the performance as an error obtained for a certain benchmark, we now investigate a task-independent property, the linear memory of the system.

  13. 非均质Euler-bernoulli梁的局部反馈定问题%Locally Distributed Feedback Stabilization of Nonuniform Euler-Bernoulli Beam

    Institute of Scientific and Technical Information of China (English)

    闫庆旭; 侯瑞鸿; 冯德兴; 齐剑冷

    2005-01-01

    In this article, we study the locally distributed feedback stabilization problem of a nonuniform Euler-Bernoulli beam. Firstly, using the semi-group theory, we establish the wellposedness of the associated closed loop system. Then by proving the uniqueness of the solution to a related ordinary differential equation, we derive the asymptotic stability of the closed loop system. Finally, by means of the piecewise multiplier method, we prove that, by either one distributed force feedback or a distributed moment feedback control, the closed loop system can be exponentially stabilized.

  14. Design considerations for a feedback system to control self-bunching in ion-storage rings

    International Nuclear Information System (INIS)

    We discuss the feasibility of a feedback system to cure self-bunching of the electron-cooled coasting ion-beam in CELSIUS. Such a system may also aid stable operation of accumulator rings for future spallation neutron sources or heavy ion rings used for inertial fusion energy production

  15. Simulation of a Feedback System for the Attenuation of e-Cloud Driven Instability

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J.-L.; Furman, M.A.; Fox, J.; Rivetta, C.; de Maria, R.; Rumolo, G.

    2009-05-04

    Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. Recently, it has been proposed to use feedback systems operating at high frequency (in the GHz range) to damp single-bunch transverse coherent oscillations that may otherwise be amplified during the interaction of the beam with ambient electron clouds. We have used the simulation package WARP-POSINST and the code Headtail to study the growth rate and frequency patterns in space-time of the electron cloud driven beam breakup instability in the CERN SPS accelerator with, or without, an idealized feedback model for damping the instability.

  16. Simulation of a Feedback System for the Attenuation of e-Cloud Driven Instability

    International Nuclear Information System (INIS)

    Electron clouds impose limitations on current accelerators that may be more severe for future machines, unless adequate measures of mitigation are taken. Recently, it has been proposed to use feedback systems operating at high frequency (in the GHz range) to damp single-bunch transverse coherent oscillations that may otherwise be amplified during the interaction of the beam with ambient electron clouds. We have used the simulation package WARP-POSINST and the code Headtail to study the growth rate and frequency patterns in space-time of the electron cloud driven beam breakup instability in the CERN SPS accelerator with, or without, an idealized feedback model for damping the instability.

  17. Development of an optical feedback based high accuracy beam transmissometer

    Science.gov (United States)

    Bartz, Robert

    1987-11-01

    The Phase I research has addressed the need for spectral light transmission data. Over the years the oceanographic community has repeatedly asked for a transmissometer operating at other wavelengths, specifically blue and green. The existing Sea Tech transmissometer is only available with a red LED, (light emitting diode) light source, mainly because LED's at shorter wavelengths have much lower power output. The primary objective of Phase I research was to determine if the transmissometer could be redesigned using LED's of other wavelengths. Constraints imposed on the new design was to achieve the same high performance inherent in the existing red transmissometer that has served the oceanic community so well for over 10 years. During the research performed in Phase I of this project a methodology and technique has been successfully developed for the stabilization of low power LED light sources to be used in the transmissometer. During the Phase I research, both red and blue LED's were evaluated in a optical bridge configuration allowing stabilization of the LED's using optical feedback. The LED's were installed in a collimator having a spatial filter 0.25 mm in diameter and a lens with a focal length of 60 mm resulting in a collimation angle of 4.16 milliradians in air. This same high degree of collimation is used in the existing Sea Tech red transmissometer.

  18. Status of digital bunch-by-bunch feedback systems at DELTA and their application as diagnostics tools

    International Nuclear Information System (INIS)

    Digital bunch-by-bunch feedback systems allow to detect and counteract longitudinal as well as transverse multi-bunch instabilities. Beam current-dependent grow-damp measurements have been performed in order to characterize these instabilities at the DELTA storage ring. The longitudinal feedback system is used permanently during the operation of the new short-pulse facility in order to damp longitudinal bunch oscillations. Besides that, all three feedback systems are in use as excellent diagnostics tools, e.g. to investigate the injection process or to take data during sudden beam loss for post-processing.

  19. Automatic beam steering in the NSLS storage rings using closed orbit feedback

    International Nuclear Information System (INIS)

    This paper describes recent work on beam stabilization systems for the NSLS electron storage rings. It also reviews several types of detectors presently available for monitoring beam motion and describes possible schemes for stabilizing photon beams in a storage ring. Finally, it briefly discusses plans for simultaneous stabilization of many beam lines in the storage rings. (orig.)

  20. Automatic beam steering in the NSLS [National Synchrotron Light Source] storage rings using closed orbit feedback

    International Nuclear Information System (INIS)

    This paper describes recent work on beam stabilization systems for the NSLS electron storage rings. It also reviews several types of detectors presently available for monitoring beam motion and describes possible schemes for stablizing photon beams in a storage ring. Finally, it briefly discusses plans for simultaneous stabilization of many beam lines in the storage rings

  1. Status of the bunch-by-bunch fast-feedback system at ANKA

    Energy Technology Data Exchange (ETDEWEB)

    Marsching, Sebastian; Hiller, Nicole; Huttel, Erhard; Judin, Vitali; Kehrer, Benjamin; Klein, Marit; Meuter, Christina; Mueller, Anke-Susanne; Nasse, Michael; Schuh, Marcel; Smale, Nigel; Streichert, Max [Karlsruhe Institute of Technology (Germany)

    2012-07-01

    At ANKA, the synchrotron light source of the Karlsruhe Institute of Technology, a vertical bunch-by-bunch fast-feedback system is being commissioned for damping multi-bunch instabilities and performing beam-dynamics studies. The ANKA synchrotron operates at a regular beam energy of 2.5 GeV while the ANKA injector operates at only 0.5 GeV. Thus, the beam injected into the synchrotron has to be ramped up in energy. Therefore, the fast-feedback system has to be able to damp instabilities over the whole energy range from 0.5 to 2.5 GeV. In this talk, we summarize the progress of the commissioning process and present studies we performed on compensating effects caused by the change of beam energy.

  2. A Classification of Adaptive Feedback in Educational Systems for Programming

    OpenAIRE

    Nguyen-Thinh Le

    2016-01-01

    Over the last three decades, many educational systems for programming have been developed to support learning/teaching programming. In this paper, feedback types that are supported by existing educational systems for programming are classified. In order to be able to provide feedback, educational systems for programming deployed various approaches to analyzing students’ programs. This paper identifies analysis approaches for programs and introduces a classification for adaptive feedback suppo...

  3. Beam alignment system for laser welding system

    International Nuclear Information System (INIS)

    The patent describes a beam alignment system for laser welding work pieces, such as fuel rod grids for nuclear fuel assemblies. The apparatus for performing various laser-machining comprises a beam alignment system including alignment target means, as well as means for emitting, directing and focusing the laser beam. (U.K.)

  4. Transient Beam Loading in the ALS Harmonic RF System

    International Nuclear Information System (INIS)

    We report on the commissioning of a higher harmonic radiofrequency system at the Advanced Light Source, designed to improve the beam lifetime. We have achieved an increase above a factor of two in our best results up to now. Transient beam loading of the harmonic cavities, due to the unequal fill patterns, creates the greatest limitations on lifetime improvement. We also describe several interesting effects on the operation of the longitudinal and transverse multibunch feedback systems

  5. The output feedback control for uncertain nonholonomic systems

    Institute of Scientific and Technical Information of China (English)

    Qiangde WANG; Chunling WEI; Siying ZHANG

    2006-01-01

    This paper considers the problems of almost asymptotic stabilization and global asymptotic regulation (GAR) by output feedback for a class of uncertain nonholonomic systems. By combining the nonsmooth change of coordinates and output feedback domination design together, we construct a simple linear time-varying output feedback controller, which can universally stabilize a whole family of uncertain nonholonomic systems. The simulation demonstrates the effectiveness of the proposed controller.

  6. THE FONT5 PROTOTYPE ILC INTRA-TRAIN FEEDBACK SYSTEM AT ATF2

    CERN Document Server

    Apsimon, R J; Burrows, P N; Christian, G B; Constance, B; Perry, C; Resta-Lopez, J

    2011-01-01

    We present the design and beam test results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end signal processor, FPGA-based digital signal processing boards, and kicker drive amplifier have been designed, built, deployed and tested with beam in the extraction line of the KEK Accelerator Test Facility (ATF2). The system was used to provide orbit correction to the train of bunches extracted from the ATF damping ring. The latency was measured to be approximately 140 ns.

  7. Design And Analysis Of An FPGA-Based Active Feedback Damping System

    International Nuclear Information System (INIS)

    The Spallation Neutron Source (SNS) at the Oak Ridge National Laboratory is a high-intensity proton-based accelerator that produces neutron beams for neutronscattering research. As the most powerful pulsed neutron source in the world, the SNS accelerator has experienced an unprecedented beam instability that has a wide bandwidth (0 to 300MHz) and fast growth time (10 to100 s). In this paper, we propose and analyze several FPGA-based designs for an active feedback damping system. This signal processing system is the first FPGA-based design for active feedback damping of wideband instabilities in high intensity accelerators. It can effectively mitigate instabilities in highintensity protons beams, reduce radiation, and boost the accelerator s luminosity performance. Unlike existing systems, which are designed using analog components, our FPGA-based active feedback damping system offers programmability while maintaining high performance. To meet the system throughput and latency requirements, our proposed designs are guided by detailed analysis of resource and performance tradeoffs. These designs are mapped onto a reconfigurable platform that includes Xilinx Virtex-II Pro FPGAs and high-speed analog-to-digital and digital-toanalog converters. Our results show that our FPGA-based active feedback damping system can provide increased flexibility and improved signal processing performance that are not feasible with existing analog systems.

  8. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    CMS Collaboration

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. In this talk we will describ...

  9. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    Stifter, Kelly Marie

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to supress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. In this talk we will descri...

  10. The CMS Beam Halo Monitor Detector System

    CERN Document Server

    Stifter, Kelly

    2015-01-01

    A new Beam Halo Monitor (BHM) detector system has been installed in the CMS cavern to measure the machine-induced background (MIB) from the LHC. This background originates from interactions of the LHC beam halo with the final set of collimators before the CMS experiment and from beam gas interactions. The BHM detector uses the directional nature of Cherenkov radiation and event timing to select particles coming from the direction of the beam and to suppress those originating from the interaction point. It consists of 40 quartz rods, placed on each side of the CMS detector, coupled to UV sensitive PMTs. For each bunch crossing the PMT signal is digitized by a charge integrating ASIC and the arrival time of the signal is recorded. The data are processed in real time to yield a precise measurement of per-bunch-crossing background rate. This measurement is made available to CMS and the LHC, to provide real-time feedback on the beam quality and to improve the efficiency of data taking. Here, I present the detector...

  11. Is the ebay feedback system really efficient ? an experimental study

    OpenAIRE

    David Masclet; Thierry Pénard

    2008-01-01

    The eBay Feedback Forum is claimed to be a crucial component of the success of eBay. Many empirical studies have found that this feedback system exerts a deterrent effect on the opportunistic behavior the Internet's anonymity may incite buyers and sellers to adopt. The feedback system in place on eBay is however far from being perfect and may be especially vulnerable to strategic ratings (or nonratings) that might reduce the informational content of feedback profiles. This article aims to exa...

  12. Feedback control design for discrete-time piecewise affine systems

    Institute of Scientific and Technical Information of China (English)

    XU Jun; XIE Li-hua

    2007-01-01

    This paper investigates the design of state feedback and dynamic output feedback stabilizing controllers for discrete-time piecewise affine (PWA) systems. The main objective is to derive design methods that will incorporate the partition information of the PWA systems so as to reduce the design conservatism embedded in existing design methods. We first introduce a transformation that converts the feedback control design problem into a bilinear matrix inequality (BMI) problem. Then, two iterative algorithms are proposed to compute the feedback controllers characterized by the BMI. Several simulation examples are given to demonstrate the advantages of the proposed design.

  13. Design of output feedback controller for a unified chaotic system

    Institute of Scientific and Technical Information of China (English)

    Li Wen-Lin; Chen Xiu-Qin; Shen Zhi-Ping

    2008-01-01

    In this paper,the synchronization of a unified chaotic system is investigated by the use of output feedback controllers;a two-input single-output feedback controller and single-input single-output feedback controller are presented to synchronize the unified chaotic system when the states are not all measurable.Compared with the existing results,the controllers designed in this paper have some advantages such as small feedback gain,simple structure and less conservation.Finally,numerical simulations results are provided to demonstrate the validity and effectiveness of the proposed method.

  14. An FPGA-based Bunch-by-Bunch Position and Angle Feedback System at ATF2

    CERN Document Server

    Christian, G B; Bett, D R; Burrows, P N; Constance, B; Davis, M R; Gerbershagen, A; Perry, C; Resta Lopez, J

    2011-01-01

    The FONT5 intra-train feedback system serves as a prototype for an interaction point beam-based feedback system for future electron-positron colliders, such as the International Linear Collider. The system has been tested on the KEK Accelerator Test Facility (ATF) and is deployed to stabilise the beam orbit at the ATF2. The goal of this system is to correct both position and angle jitter in the vertical plane, providing stability of ~1 micron at the entrance to the ATF2 final-focus system. The system comprises three stripline beam position monitors (BPMs) and two stripline kickers, custom low-latency analogue front-end BPM processors, a custom FPGA-based digital processing board with fast ADCs, and custom kicker-drive amplifiers. An overview of the hardware, and the latest results from beam tests at ATF2, will be presented. The total latency of the system with coupled position and angle feedback loops operating simultaneously was measured to be approximately 140 ns. The greatest degree of correction observed ...

  15. Dynamic axial stabilization of counterpropagating beam-traps with feedback control

    DEFF Research Database (Denmark)

    Tauro, Sandeep; Bañas, Andrew Rafael; Palima, Darwin;

    2010-01-01

    Optical trapping in a counter-propagating (CP) beam-geometry provides unique advantages in terms of working distance, aberration requirements and intensity hotspots. However, its axial performance is governed by the wave propagation of the opposing beams, which can limit the practical geometries...... real-time rapid repositioning coupled with a strongly enhanced axial trapping for a plurality of particles of varying sizes. We also demonstrate the technique’s adaptability for real-time reconfigurable feedback-trapping of a dynamically growing structure that mimics a continuously dividing cell colony...

  16. Proposed Reactor Operating Experience Feedback System Development

    International Nuclear Information System (INIS)

    Most events occurring in nuclear power plants are not individually significant, and prevented from progressing to accident conditions by a series of barriers against core damage and radioactive releases. Significant events, if occur, are almost always a breach of these multiple barriers. As illustrated in the 'Swiss cheese' model, the individual layers of defense or 'cheese slices' have weakness or 'holes.' These weaknesses are inconstant, i.e., the holes are open or close at random. When by chance all the holes are aligned, a hazard causes the significant event of concern. Elements of low significant events, inattention to detail, time or economic pressure, uncorrected poor practices/habits, marginal maintenance and equipment care, etc., make holes in the layers of defense; some elements may make more holes in different layers, incurring more chances to be aligned. An effective reduction of the holes, therefore, is gained through better knowledge or awareness of increasing trends of the event elements, followed by appropriate actions. According to the Swiss cheese metaphor, attention to the Operating Experience (OE) feedback system, as opposed to the individual and to randomness, is drawn from a viewpoint of reactor safety

  17. Quantitative Feedback Control of Multiple Input Single Output Systems

    OpenAIRE

    Javier Rico-Azagra; Montserrat Gil-Martínez; Jorge Elso

    2014-01-01

    This paper presents a robust feedback control solution for systems with multiple manipulated inputs and a single measurable output. A structure of parallel controllers achieves robust stability and robust disturbance rejection. Each controller uses the least possible amount of feedback at each frequency. The controller design is carried out in the Quantitative Feedback Theory framework. The method pursues a smart load sharing along the frequency spectrum, where each branch must either coll...

  18. Designing new feedback mangement system Långvik

    OpenAIRE

    Dang, Hien

    2014-01-01

    This thesis is a design project on the field of feedback management, conducted for Långvik hotel. The purpose of this thesis is to recommend a new feedback management system for the hotel that can effectively recognize original reasons for customers’ returning decision. The new approach to feedback management is expected to generate a higher number of re- turned customers subsequent to the summer business peak. The literature review focuses on the connection between customer experience and...

  19. Combined feedforward and feedback control of end milling system

    OpenAIRE

    F. Cus; U. Zuperl; J. Balic

    2011-01-01

    Purpose: Purpose of this paper. An intelligent control system is presented that uses a combination of feedforward and feedback for cutting force control in end milling.Design/methodology/approach: The network is trained by the feedback output that is minimized during training and most control action for disturbance rejection is finally performed by the rapid feedforward action of the network.Findings: The feedback controller corrects for errors caused by external disturbances. The feedforward...

  20. Optical encoder feedback system for levitating rotor system

    Science.gov (United States)

    Khanna, Shrey; Ho, Joe N.; Irwen, Jonathan; Rakka, Gurjinder; Wang, Weichih

    2010-03-01

    This paper describes the design and fabrication of feedback control system for a three phase motor with a diamagnetically levitating rotor. The planar rotor described in this paper uses a triangular configuration of magnets that rotates due to nine electric coils evenly spaced around the rotor. An optical mechanical feedback system controls the frequency at which the rotor spins. The current input to the coil is controlled by a mechanical relay circuit which latches based on a DC pulse signal generated by a PID control algorithm. The mechanical relay circuit allows current to flow to each coils (the actuators of this system), which then produces a magnetic field strong enough to spin the rotor.

  1. Information feedback strategy for beltways in intelligent transportation systems

    Science.gov (United States)

    Li, Wen-Ting; Li, Jian-Qing; Chen, Bo-Kui; Huang, Xin; Wang, Zhen

    2016-03-01

    As an important part of the Intelligent Transportation System (ITS), the information feedback strategy has drawn more and more scholars' attention. A variety of feedback strategies are proposed to improve the traffic efficiency. These strategies are based on simple route scenarios, but most route scenarios are always complex in reality. In this letter, based on a complex beltway scenario, we propose a new traffic information feedback strategy called Beltway Feedback Strategy (BFS). The simulation results show that the BFS can effectively improve the transportation ability of beltways.

  2. Geometric Structures of Stable Time-Variant State Feedback Systems

    Institute of Scientific and Technical Information of China (English)

    ZHONG Feng-wei; SUN Hua-fei; ZHANG Zhen-ning

    2007-01-01

    A new technique for considering the stabilizing time-variant state feedback gains is proposed from the viewpoint of information geometry. First, parametrization of the set of all stabilizing time-variant state feedback gains is given. Moreover, a diffeomorphic structure between the set of stabilizing time-variant state feedback gains and the Cartesian product of positive definite matrix and skew symmetric matrix satisfying certain algebraic conditions is constructed. Furth ermore, an immersion and some results about the eigenvalue locations of stable state feedback systems are derived.

  3. A waveguide overloaded cavity kicker for the HLS II longitudinal feedback system

    CERN Document Server

    Li, Wubin; Sun, Baogen; Wu, Fangfang; Xu, Wei; Lu, Ping; Yang, Yongliang

    2013-01-01

    In the upgrade project of Hefei Light Source (HLS II), a new digital longitudinal bunch-by-bunch feedback system will be developed to suppress the coupled bunch instabilities in the storage ring effectively. We design a new waveguide overloaded cavity longitudinal feedback kicker as the feedback actuator. The beam pipe of the kicker is racetrack shape so as to avoid a transition part to the octagonal vacuum chamber. The central frequency and the bandwidth of the kicker have been simulated and optimized to achieve design goals by the HFSS code. The higher shunt impedance can be obtained by using a nose cone to reduce the feedback power requirement. Before the kicker cavity was installed in the storage ring, a variety of measurements were carried out to check its performance. All these results of simulation and measurement are presented.

  4. Design of active feedback controller used in the infrared beam line of SSRF

    International Nuclear Information System (INIS)

    Background: The infrared beam line consists of many kinds of optical components that are susceptible to the external mechanical vibration, which will be further amplified by the long optical paths to seriously destroy the stability of infrared beam position. Purpose: The active feedback controller is used to stabilize the infrared beam position disturbed by the external environment. Methods: The design of the active feedback controller used in the infrared beam line of SSRF was proposed in this paper firstly, which included its background, light-path layout and operating process. Subsequently, the selections of the crucial components such as detector and actuator were discussed in details. Finally, the correction compensator design and its experimental test were also presented. The correction compensator design was realized by utilizing the frequency response method, and tested in time domain, frequency domain and mathematical model simulation of the controlled object. Results: The experimental tests included time domain step response signal of the controller, the time domain signal and its relevant magnitude spectrum in frequency domain due to the light source simulation vibration. Conclusion: The results show that the maximum effective operating band is 250 Hz and the maximum steady error is 5 μm. (authors)

  5. Digital closed orbit feedback system for the advanced photon source storage ring

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) is a dedicated third-generation synchrotron light source with a nominal energy of 7 GeV and a circumference of 1104 m. The closed orbit feedback system for the APS storage ring employs unified global and local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described in this paper. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm, application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware including the DSPs is distributed in 20 VME crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories

  6. Digital closed orbit feedback system for the advanced photon source storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.; Barr, D.; Decker, G. [and others

    1995-12-31

    The Advanced Photon Source (APS) is a dedicated third-generation synchrotron light source with a nominal energy of 7 GeV and a circumference of 1104 m. The closed orbit feedback system for the APS storage ring employs unified global and local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described in this paper. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm, application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware including the DSPs is distributed in 20 VME crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories.

  7. Nonlinear feedback synchronization of hyperchaos in higher dimensional systems

    Institute of Scientific and Technical Information of China (English)

    FangJin-Qing; AliMK

    1997-01-01

    Nonlinear feedback functional method is presented to realize synchronization of hyperchaos in higher dimensional systems,New nonlinear feedback functions and superpositions of linear and nonlinear feedback functions are also introduced to synchronize hyperchaos.The robustness of the method based on the flexibility of choices of feedback functions is discussed.By coupling well-known chaotic or chaotic-hyperchaotic systems in low-dimensional systems,such as Lorenz system,Van der Pol oscillator,Duffing oscillator and Roessler system,ten dimensional hyperchaotic systems are formed as the model systems.It can be found that there is not any noticeable difference in synchronization based on the numbers of positive Lyapunov exponents and of dimensions.

  8. A closed loop feedback system for synchrotron radiation double crystal monochromators

    International Nuclear Information System (INIS)

    We report on a dc closed loop feedback system for a fixed exit double crystal monochromator. The feedback control is part of a complete system which includes beam position and current monitors. The monochromator consists of two identical crystals mechanically coupled so that the two diffraction planes are almost parallel to each other. The feedback system controls a piezoelectric transducer to maintain the new parallelism, and it can be set under computer control to be at any point in the rocking curve at all times. The system has been thoroughly tested and found to be adequate for EXAFS measurements performed on beamline X18B at the National Synchrotron Light Source at Brookhaven National Laboratory. (orig.)

  9. Beam Cleaning and Collimation Systems

    CERN Document Server

    Redaelli, S

    2016-01-01

    Collimation systems in particle accelerators are designed to dispose of unavoidable losses safely and efficiently during beam operation. Different roles are required for different types of accelerator. The present state of the art in beam collimation is exemplified in high-intensity, high-energy superconducting hadron colliders, like the CERN Large Hadron Collider (LHC), where stored beam energies reach levels up to several orders of magnitude higher than the tiny energies required to quench cold magnets. Collimation systems are essential systems for the daily operation of these modern machines. In this document, the design of a multistage collimation system is reviewed, taking the LHC as an example case study. In this case, unprecedented cleaning performance has been achieved, together with a system complexity comparable to no other accelerator. Aspects related to collimator design and operational challenges of large collimation systems are also addressed.

  10. Corresponding Angle Feedback in an innovative weighted transportation system

    Science.gov (United States)

    Dong, Chuanfei; Ma, Xu

    2010-05-01

    The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. In this Letter, we study dynamics of traffic flow with real-time information. The influence of a feedback strategy named Corresponding Angle Feedback Strategy (CAFS) is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  11. Beam steering system

    Science.gov (United States)

    Bowhill, S. A.; Merewether, K. O.

    1986-01-01

    A simple technique for steering the beam of a multimodule phased array MST (mesosphere, stratosphere, troposphere) radar antenna is described. It is desirable to be able to point the antenna in multiple directions, so as to derive all components of the horizontal velocity. This was done on an experimental basis by adding parallel wire line to the feed and achieving a southward tilt of the antenna. It is proved possible to steer the beam through most of the available range without adversely affecting the VSWR seen from the transmitter. Calibrating the antenna direction can be accomplished by observing radio sources, though there are an inadequate number to cover all directions. For various assumed values of the aspect sensitivity in dB/deg, and the calculated antenna pattern, it is possible to calculate the effective pointing angle of the antenna, defined as that angle which would give an identical location for the centroid of the power spectrum if aspect sensitivity were absent. Using averaged apparent steering directions, eastward and northward winds were calculated for special radar runs simultaneous with 14 balloon launches at Peoria and results are presented.

  12. Truncated predictor feedback for time-delay systems

    CERN Document Server

    Zhou, Bin

    2014-01-01

    This book provides a systematic approach to the design of predictor based controllers for (time-varying) linear systems with either (time-varying) input or state delays. Differently from those traditional predictor based controllers, which are infinite-dimensional static feedback laws and may cause difficulties in their practical implementation, this book develops a truncated predictor feedback (TPF) which involves only finite dimensional static state feedback. Features and topics: A novel approach referred to as truncated predictor feedback for the stabilization of (time-varying) time-delay systems in both the continuous-time setting and the discrete-time setting is built systematically Semi-global and global stabilization problems of linear time-delay systems subject to either magnitude saturation or energy constraints are solved in a systematic manner Both stabilization of a single system and consensus of a group of systems (multi-agent systems) are treated in a unified manner by applying the truncated pre...

  13. Digital closed orbit feedback system for the Advanced Photon Source storage ring

    International Nuclear Information System (INIS)

    Closed orbit feedback for the Advanced Photon Source (APS) storage ring employs unified global an local feedback systems for stabilization of particle and photon beams based on digital signal processing (DSP). Hardware and software aspects of the system will be described. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm. application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware, including the DSPS, is distributed in 20 VNE crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically-networked reflective memories

  14. Digital closed orbit feedback system for the Advanced Photon Source storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Y.; Barr, D.; Decker, G.; Galayda, J.; Lenkszus, F.; Lumpkin, A.; Votaw, A.J. [Accelerator Systems Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States)

    1996-09-01

    Closed orbit feedback for the Advanced Photon Source (APS) storage ring employs unified global and local feedback systems for stabilization of particle and photon beams based on digital signal processing. Hardware and software aspects of the system will be described. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm, application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware, including the digital signal processor (DSPs), is distributed in 20 VME crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically networked reflective memories. {copyright} {ital 1996 American Institute of Physics.}

  15. Digital closed orbit feedback system for the Advanced Photon Source storage ring

    Science.gov (United States)

    Chung, Y.; Barr, D.; Decker, G.; Galayda, J.; Lenkszus, F.; Lumpkin, A.; Votaw, A. J.

    1996-09-01

    Closed orbit feedback for the Advanced Photon Source (APS) storage ring employs unified global and local feedback systems for stabilization of particle and photon beams based on digital signal processing. Hardware and software aspects of the system will be described. In particular, we will discuss global and local orbit feedback algorithms, PID (proportional, integral, and derivative) control algorithm, application of digital signal processing to compensate for vacuum chamber eddy current effects, resolution of the interaction between global and local systems through decoupling, self-correction of the local bump closure error, user interface through the APS control system, and system performance in the frequency and time domains. The system hardware, including the digital signal processor (DSPs), is distributed in 20 VME crates around the ring, and the entire feedback system runs synchronously at 4-kHz sampling frequency in order to achieve a correction bandwidth exceeding 100 Hz. The required data sharing between the global and local feedback systems is facilitated via the use of fiber-optically networked reflective memories.

  16. Fast digital transverse feedback system for bunch train operation in CESR

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.T.; Billing, M.G.; Dobbins, J.A. [Cornell Univ., Ithaca, NY (United States). Lab. of Nuclear Studies] [and others

    1996-08-01

    We have developed a time domain transverse feedback system with the high bandwidth needed to control transverse instabilities when the CESR e{sup +}e{sup -} collider is filled with trains of closely spaced bunches. This system is based on parallel digital processors and a stripline driver. It is capable of acting on arbitrary patterns of bunches having a minimum spacing of 14 ns. Several simplifying features have been introduced. A single shorted stripline kicker driven by one power amplifier is used to control both counter-rotating beams. The desired feedback phase is achieved by sampling the bunch position at a single location on two independently selectable beam revolutions. The system adapts to changes in the betatron tune, bunch pattern, or desired damping rate through the loading of new parameters into the digital processors via the CESR control system. The feedback system also functions as a fast gated bunch current monitor. Both vertical and horizontal loops are now used in CESR operation. The measured betatron damping rates with the transverse feedback system in operation are in agreement with the analytical prediction and a computer simulation developed in connection with this work. (author)

  17. Fast digital transverse feedback system for bunch train operation in CESR

    International Nuclear Information System (INIS)

    We have developed a time domain transverse feedback system with the high bandwidth needed to control transverse instabilities when the CESR e+e-collider is filled with trains of closely spaced bunches. This system is based on parallel digital processors and a stripline driver. It is capable of acting on arbitrary patterns of bunches having a minimum spacing of 14 ns. Several simplifying features have been introduced. A single shorted stripline kicker driven by one power amplifier is used to control both counter-rotating beams. The desired feedback phase is achieved by sampling the bunch position at a single location on two independently selectable beam revolutions. The system adapts to changes in the betatron tune, bunch pattern, or desired damping rate through the loading of new parameters into the digital processors via the CESR control system. The feedback system also functions as a fast gated bunch current monitor. Both vertical and horizontal loops are now used in CESR operation. The measured betatron damping rates with the transverse feedback system in operation are in agreement with the analytical prediction and a computer simulation developed in connection with this work. (author)

  18. Control of Halo-Chaos in Beam Transport Network via Neural Network Adaptation with Time-Delayed Feedback

    Institute of Scientific and Technical Information of China (English)

    FANG Jin-Qing; LUO Xiao-Shu; HUANG Guo-Xian

    2006-01-01

    Subject of the halo-chaos control in beam transport networks (channels) has become a key concerned issue for many important applications of high-current proton beam since 1990'. In this paper, the magnetic field adaptive control based on the neuralnetwork with time-delayed feedback is proposed for suppressing beam halo-chaos in the beam transport network with periodic focusing channels. The envelope radius of high-current proton beam is controlled to reach the matched beam radius by suitably selecting the control structure and parameter of the neural network, adjusting the delayed-time and control coefficient of the neural network.

  19. ITER Neutral Beam Injection System

    International Nuclear Information System (INIS)

    A Japanese design proposal of the ITER Neutral Beam Injection System (NBS) which is consistent with the ITER common design requirements is described. The injection system is required to deliver a neutral deuterium beam of 75MW at 1.3MeV to the reactor plasma and utilized not only for plasma heating but also for current drive and current profile control. The injection system is composed of 9 modules, each of which is designed so as to inject a 1.3MeV, 10MW neutral beam. The most important point in the design is that the injection system is based on the utilization of a cesium-seeded volume negative ion source which can produce an intense negative ion beam with high current density at a low source operating pressure. The design value of the source is based on the experimental values achieved at JAERI. The utilization of the cesium-seeded volume source is essential to the design of an efficient and compact neutral beam injection system which satisfies the ITER common design requirements. The critical components to realize this design are the 1.3MeV, 17A electrostatic accelerator and the high voltage DC acceleration power supply, whose performances must be demonstrated prior to the construction of ITER NBI system. (author)

  20. The SSC beam scraper system

    Energy Technology Data Exchange (ETDEWEB)

    Maslov, M.A.; Mokhov, N.V.; Yazynin (Superconducting Super Collider Lab., Dallas, TX (United States) Institut Fiziki Vysokikh Ehnergij, Protvino (USSR))

    1991-06-01

    In this paper we present the results of a full-scale study of a beam scraping system that is designed to guarantee reliable operation of the SSC throughout the whole cycle and for minimum background for experiments at the interaction regions. The machine aperture limits and beam loss formation are analyzed. Simulation programs and a calculational model are described. The physics of beam scraping is explored, and measures to increase significantly the system efficiency are determined. A tolerable scraping rate, taking into account scraper material integrity, quench limits in downstream superconducting magnets, radiation shielding requirements, and minimal beam halo levels at the IPs are also determined. Finally, a complete multi-component scraper system in the SSC East Cluster is proposed. Throughout the paper we define a scraper as a primary absorber consisting of precise movable jaws that have a flat inner edge along the circulation beam and which may be forced to touch the beam halo in horizontal or vertical planes. Secondary absorbers -- collimators -- are destined to intercept outscattered protons and other particles produced in scraper material. All these are surrounded with a radiation shielding. 15 refs., 50 figs., 13 tabs.

  1. Feedback-linearization and feedback-feedforward decentralized control for multimachine power system

    Energy Technology Data Exchange (ETDEWEB)

    De Tuglie, Enrico [Dipartimento di Ingegneria dell' Ambiente, e per lo Sviluppo Sostenibile - DIASS, Politecnico di Bari, Viale del Turismo 8, 74100 Taranto (Italy); Iannone, Silvio Marcello; Torelli, Francesco [Dipartimento di Elettrotecnica, ed Elettronica - DEE, Politecnico di Bari, Via Re David 200, 70125 Bari (Italy)

    2008-03-15

    In this paper a decentralized nonlinear controller for large-scale power systems is investigated. The proposed controller design is based on the input-output feedback linearization methodology. In order to overcome computational difficulties in adopting such methodology, the overall interconnected nonlinear system, given as n-order, is analyzed as a cascade connection of an n{sub 1}-order nonlinear subsystem and an n{sub 2}-order linear subsystem. The controller design is obtained by applying input-output feedback linearization to the nonlinear subsystem and adopting a tracking control scheme, based on feedback-feedforward technique, for the linear subsystem. In the assumed system model, which is characterised by an interconnected structure between generating units, a decentralised adaptive controller is implemented by decentralizing these constraints. The use of a totally decentralised controller implies a system performance decay with respect to performance when the system is equipped with a centralised controller. Fortunately, the robustness of the proposed controller, based on input-output feedback procedure, guarantees good performance in terms of disturbance even when disturbances are caused by decentralization of interconnection constraints. Test results, provided on the IEEE 30 bus test system, demonstrate the effectiveness and practical applicability of proposed methodology. (author)

  2. Weighted congestion coefficient feedback in intelligent transportation systems

    International Nuclear Information System (INIS)

    In traffic systems, a reasonable information feedback can improve road capacity. In this Letter, we study dynamics of traffic flow with real-time information. And the influence of a feedback strategy named Weighted Congestion Coefficient Feedback Strategy (WCCFS) is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  3. Weighted congestion coefficient feedback in intelligent transportation systems

    Science.gov (United States)

    Dong, Chuan-Fei; Ma, Xu; Wang, Bing-Hong

    2010-03-01

    In traffic systems, a reasonable information feedback can improve road capacity. In this Letter, we study dynamics of traffic flow with real-time information. And the influence of a feedback strategy named Weighted Congestion Coefficient Feedback Strategy (WCCFS) is introduced, based on a two-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. Our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting this optimal information feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  4. Indirect Identification of Linear Stochastic Systems with Known Feedback Dynamics

    Science.gov (United States)

    Huang, Jen-Kuang; Hsiao, Min-Hung; Cox, David E.

    1996-01-01

    An algorithm is presented for identifying a state-space model of linear stochastic systems operating under known feedback controller. In this algorithm, only the reference input and output of closed-loop data are required. No feedback signal needs to be recorded. The overall closed-loop system dynamics is first identified. Then a recursive formulation is derived to compute the open-loop plant dynamics from the identified closed-loop system dynamics and known feedback controller dynamics. The controller can be a dynamic or constant-gain full-state feedback controller. Numerical simulations and test data of a highly unstable large-gap magnetic suspension system are presented to demonstrate the feasibility of this indirect identification method.

  5. Large deviation theory to model systems under an external feedback

    OpenAIRE

    Gagliardi, Alessio; Pecchia, Alessandro; Di Carlo, Aldo

    2016-01-01

    In this paper we address the problem of systems under an external feedback. This is performed using a large deviation approach and rate distortion from information theory. In particular we define a lower boundary for the maximum entropy reduction that can be obtained using a feedback apparatus with a well defined accuracy in terms of measurement of the state of the system. The large deviation approach allows also to define a new set of potentials, including information, which similarly to mor...

  6. Interactive query expansion and relevance feedback for document retrieval systems

    OpenAIRE

    Efthimiadis, E.N.

    1992-01-01

    This thesis is aimed at investigating interactive query expansion within the context of a relevance feedback system that uses term weighting and ranking in searching online databases that are available through online vendors. Previous evaluations of relevance feedback systems have been made in laboratory conditions and not in a real operational environment. The research presented in this thesis followed the idea of testing probabilistic retrieval techniques in an operational environment. The ...

  7. Antiproton source beam position system

    International Nuclear Information System (INIS)

    The TeV I Beam Position Monitor (BPM) system is designed to provide a useful diagnostic tool during the commissioning and operational phases of the antiproton source. Simply stated the design goal is to provide single turn position information for intensities of > 1x109 particles, and multi-turn (clocked orbit) information for beam intensities of > 1x107 particles, both with sub-millimeter resolution. It is anticipated that the system will be used during commissioning for establishing the first turn through the Debuncher and Accumulator, for aligning injection orbits, for providing information necessary to correct closed orbits, and for measuring various machine parameters (e.g. tunes, dispersion, aperture, chromaticity). During normal antiproton operation the system will be used to monitor the beam position throughout the accumulation process

  8. Fast digital feedback control systems for accelerator RF system using FPGA

    International Nuclear Information System (INIS)

    Feedback control system plays important role for proper injection and acceleration of beam in particle accelerators by providing the required amplitude and phase stability of RF fields in accelerating structures. Advancement in the field of digital technology enables us to develop fast digital feedback control system for RF applications. Digital Low Level RF (LLRF) system offers the inherent advantages of Digital System like flexibility, adaptability, good repeatability and reduced long time drift errors compared to analog system. To implement the feedback control algorithm, I/Q control scheme is used. By properly sampling the down converted IF signal using fast ADC we get accurate feedback signal and also eliminates the need of two separate detectors for amplitude and phase detection. Controller is implemented in Vertex-4 FPGA. Codes for control algorithms which controls the amplitude and phase in all four quadrants with good accuracy are written in the VHDL. I/Q modulator works as common actuator for both amplitude and phase correction. Synchronization between RF, LO and ADC clock is indispensable and has been achieved by deriving the clock and LO signal from RF signal itself. Control system has been successfully tested in lab with phase and amplitude stability better then ±1% and ±1° respectively. High frequency RF signal is down converted to IF using the super heterodyne technique. Super heterodyne principal not only brings the RF signal to the Low IF frequency at which it can be easily processed but also enables us to use the same hardware and software for other RF frequencies with some minor modification. (author)

  9. Analysis of DSP-based longitudinal feedback system: Trials at SPEAR and ALS

    International Nuclear Information System (INIS)

    Recently a single-channel prototype of the proposed PEP-II longitudinal feedback system was successfully demonstrated at SPEAR and ALS on single-bunch beams. The phase oscillations are detected via a wide-band pick up. The feedback signal is then computed using a digital signal processor (DSP) and applied to the beam by phase modulating the rf. We analyze results in the frequency- and the time-domain and show how the closed-loop transfer functions can be obtained rigorously by proper modeling of the various components of this hybrid continuous/digital system. The technique of downsampling was used in the experiments to reduce the number of computations and allowed the use of the same digital hardware on both machines

  10. Simulation Results of a Feedback Control System to Damp Electron Cloud Single-Bunch Transverse Instabilities In The Cern SPS

    Energy Technology Data Exchange (ETDEWEB)

    Secondo, R.; Vay, J. L.; Venturini, M.; Fox, J. D.; Rivetta, C. H.; Hofle, W.

    2011-03-28

    Transverse Single-Bunch Instabilities due to the Electron Cloud effect are limiting the operation at high current of the SPS at CERN. Recently a high-bandwidth Feedback System has been proposed as a possible solution to stabilize the beam and is currently under study. We analyze the dynamics of the bunch actively damped with a simple model of the Feedback in the macro-particle code WARP, in order to investigate the limitations of the System such as the minimum amount of power required to maintain stability. We discuss the feedback model, report on simulation results and present our plans for further development of the numerical model.

  11. Inversion and Feedback Research on the Temperature Control and Crack Prevention for Concrete Crane Beam on Rock Wall

    OpenAIRE

    Yang Zhang; Sheng Qiang

    2011-01-01

    Concrete crane beam on a rock wall on a new structure used in underground building has become more common in recent year. But the concrete beam cracking problem always perplexes scientists and engineers. In order to solve this, the construction information inversion and feedback analysis method is applied. A beam section was taken as a prototype experiment. The temperature and construction data was collected to inverse some necessary thermal parameters. According to the characteristics of con...

  12. Behavioral System Feedback Measurement Failure: Sweeping Quality under the Rug

    Science.gov (United States)

    Mihalic, Maria T.; Ludwig, Timothy D.

    2009-01-01

    Behavioral Systems rely on valid measurement systems to manage processes and feedback and to deliver contingencies. An examination of measurement system components designed to track customer service quality of furniture delivery drivers revealed the measurement system failed to capture information it was designed to measure. A reason for this…

  13. SIMULATION OF E-CLOUD DRIVEN INSTABILITY AND ITS ATTENUATION USING A FEEDBACK SYSTEM IN THE CERN SPS

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J.-L.; Byrd, J. M.; Furman, M. A.; Secondo, R.; Venturini, M.; Fox, J. D.; Rivetta, C. H.; Hofle, W.

    2010-05-03

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS [1], and a feedback system to control the instabilities is under active development [2]. We present the latest improvements to the Warp-Posinst simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS.

  14. Simulation of E-Cloud driven instability and its attenuation using a feedback system in the CERN SPS

    CERN Document Server

    Vay, JL; Furman, M; Secondo, R; Venturini, M; Fox, J; Rivetta, C; Hofle, W

    2010-01-01

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS [1], and a feedback system to control the instabilities is under active development [2]. We present the latest improvements to the Warp-Posinst simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS.

  15. Simulation of E-Cloud Driven Instability And Its Attenuation Using a Feedback System in the CERN SPS

    Energy Technology Data Exchange (ETDEWEB)

    Vay, Jean-Luc; /LBL, Berkeley; Byrd, John; /LBL, Berkeley; Furman, Miguel; /LBL, Berkeley; Penn, Gregory; /LBL, Berkeley; Secondo, Raffaello; /LBL, Berkeley; Venturini, Marco /LBL, Berkeley; Fox, John; /SLAC; Rivetta, Claudio; /SLAC

    2012-07-06

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the instabilities is under active development. We present the latest improvements to the Warp-Posinst simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS.

  16. Simulation of E-Cloud Driven Instability And Its Attenuation Using a Feedback System in the CERN SPS

    International Nuclear Information System (INIS)

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the instabilities is under active development. We present the latest improvements to the Warp-Posinst simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS.

  17. SIMULATION OF E-CLOUD DRIVEN INSTABILITY AND ITS ATTENUATION USING A FEEDBACK SYSTEM IN THE CERN SPS

    International Nuclear Information System (INIS)

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS (1), and a feedback system to control the instabilities is under active development (2). We present the latest improvements to the Warp-Posinst simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS.

  18. Optimal nonlinear feedback control of quasi-Hamiltonian systems

    Institute of Scientific and Technical Information of China (English)

    朱位秋; 应祖光

    1999-01-01

    An innovative strategy for optimal nonlinear feedback control of linear or nonlinear stochastic dynamic systems is proposed based on the stochastic averaging method for quasi-Hamiltonian systems and stochastic dynamic programming principle. Feedback control forces of a system are divided into conservative parts and dissipative parts. The conservative parts are so selected that the energy distribution in the controlled system is as requested as possible. Then the response of the system with known conservative control forces is reduced to a controlled diffusion process by using the stochastic averaging method. The dissipative parts of control forces are obtained from solving the stochastic dynamic programming equation.

  19. Uniform and Model-Driven Engineering of Feedback Control Systems

    OpenAIRE

    Křikava, Filip; Collet, Philippe; Blay-Fornarino, Mireille

    2011-01-01

    Engineering and reusing feedback control systems face challenging issues, such as structuring control loops to allow for fine-grained reasoning about their architecture. We propose a model-driven approach in which all major parts of the feedback control are uniformly designed as first-class adaptive elements. Expected properties of the approach are discussed and illustrated on a real scenario of overload control in a grid middleware.

  20. Output feedback for linear multivariable systems with parameter uncertainty.

    Science.gov (United States)

    Basuthakur, S.; Knapp, C. H.

    1973-01-01

    A minimax design method is applied to the problem of obtaining an acceptable output feedback matrix for linear multivariable systems with parameter uncertainty. The result is a set of nonlinear matrix equations (similar to those obtained by Levine and Athans (1970)), which must be solved for the feedback matrix. An example illustrates the technique and the fact that better results are achieved for large parameter variation than with a purely nominal design.

  1. Implementing a Measurement Feedback System: A Tale of Two Sites.

    Science.gov (United States)

    Bickman, Leonard; Douglas, Susan R; De Andrade, Ana Regina Vides; Tomlinson, Michele; Gleacher, Alissa; Olin, Serene; Hoagwood, Kimberly

    2016-05-01

    A randomized experiment was conducted in two outpatient clinics evaluating a measurement feedback system called contextualized feedback systems. The clinicians of 257 Youth 11-18 received feedback on progress in mental health symptoms and functioning either every 6 months or as soon as the youth's, clinician's or caregiver's data were entered into the system. The ITT analysis showed that only one of the two participating clinics (Clinic R) had an enhanced outcome because of feedback, and only for the clinicians' ratings of youth symptom severity on the SFSS. A dose-response effect was found only for Clinic R for both the client and clinician ratings. Implementation analyses showed that Clinic R had better implementation of the feedback intervention. Clinicians' questionnaire completion rate and feedback viewing at Clinic R were 50 % higher than clinicians at Clinic U. The discussion focused on the differences in implementation at each site and how these differences may have contributed to the different outcomes of the experiment. PMID:25876736

  2. ATF neutral beam injection system

    International Nuclear Information System (INIS)

    The Advanced Toroidal Facility is a stellarator torsatron being built at Oak Ridge National Laboratory to investigate improved plasma confinement schemes. Plasmas heating will be carried out predominantly by means of neutral beam injection. This paper describes the basic parameters of the injection system. Numerical calculations were done to optimize the aiming of the injectors. The results of these calculations and their implications on the neutral power to the machine are elaborated. The effects of improving the beam optics and altering the focal length on the power transmitted to the plasma are discussed

  3. Observation, control and modal analysis of longitudinal coupled-bunch instabilities in the ALS via a digital feedback system

    International Nuclear Information System (INIS)

    The operation of a longitudinal multi-bunch damping system using digital signal processing techniques is shown via measurements from the LBL Advanced Light Source. The feedback system (developed for use by PEP-II, ALS and DAΦNE) uses a parallel array of signal processors to implement a bunch by bunch feedback system for sampling rates up to 500 MHz. The programmable DSP system allows feedback control as well as accelerator diagnostics. A diagnostic technique is illustrated which uses the DSP system to excite and then damp the beam. The resulting 12 ms time domain transient is Fourier analyzed to provide the simultaneous measurement of growth rates and damping rates of all unstable coupled-bunch beam modes

  4. Observation, control, and modal analysis of longitudinal coupled-bunch instabilities in the ALS via a digital feedback system

    International Nuclear Information System (INIS)

    The operation of a longitudinal multibunch damping system using digital signal processing (DSP) techniques is shown via measurements from the Lawrence Berkeley Laboratory (LBL) Advanced Light Source (ALS). The feedback system (developed for use by PEP-II, ALS, and DAΦNE) uses a parallel array of signal processors to implement a bunch-by-bunch feedback system for sampling rates up to 500 MHz. The programmable DSP system allows feedback control as well as accelerator diagnostics. A diagnostic technique is illustrated which uses the DSP system to excite and then damp the beam. The resulting 12-ms time domain transient is Fourier analyzed to provide the simultaneous measurement of growth rates and damping rates of all unstable coupled-bunch beam modes. copyright 1997 American Institute of Physics

  5. Quantum feedback in a non-resonant cavity QED system

    International Nuclear Information System (INIS)

    Photon correlation measurements reveal the response of the conditional evolution of the cavity QED system to a novel quantum feedback protocol. A photodetection collapses the state of the system and triggers a feedback pulse with an adjustable delay and amplitude that alters the intensity driving the system. The conditional evolution of the system freezes into a new steady state where it resides until, after an amount of time determined by the experimenter, it re-equilibrates into the original steady state. We carry out a sensitivity analysis using a theoretical model with atomic detuning and make quantitative comparisons with measured results

  6. Asymptotic stabilization of nonlinear systems using state feedback

    International Nuclear Information System (INIS)

    This paper studies the design of state-feedback controllers for the stabilization of single-input single-output nonlinear systems x = f(x) + g(x)u, y = h(x). Two approaches for the stabilization problem are given; the asymptotic stability is achieved by means of: a) nonlinear state feedback: two nonlinear feedbacks are used; the first separates the system in a controllable linear part and in the zeros-dynamic part. The second feedback generates an asymptotically stable equilibrium on the manifold where this dynamics evolves; b) nonlinear dynamic feedback: conditions are established under which the system can follow the output of a completely controllable bilinear system which uses bounded controls. This fact enables the system to reach, using bounded controls too, a desired output value in finite time. As this value corresponds to a state that lays in the attraction basin of a stable equilibrium with the same output, the system evolves to that point. The two methods are illustrated by examples. (Author)

  7. Mitigation of ground motion effects via feedback systems for the Compact Linear Collider

    International Nuclear Information System (INIS)

    The Compact Linear Collider (CLIC) is a future multi-TeV electron positron collider, which is currently being designed at CERN. To achieve its ambitious goals, CLIC has to produce particle beams of the highest quality, which makes the accelerator very sensitive to ground motion. Four mitigation methods have been foreseen by the CLIC design group to cope with the feasibility issue of ground motion. This thesis is concerned with the design of one of these mitigation methods, named linac feedback (L-FB), but also with the simultaneous simulation and validation of all mitigation methods. Additionally, a technique to improve the quality of the indispensable system knowledge has been developed. The L-FB suppresses beam oscillations along the accelerator. Its design is based on the decoupling of the overall accelerator system into independent channels. For each channel an individual compensator is found with the help of a semi- automatic control synthesis procedure. This technique allows the designer to incorporate expert knowledge, which is used by an optimisation algorithm to minimise the luminosity loss due to ground motion. This approach speeds up the design process significantly, while at the same time improving the orbit feedback performance compared to standard methods. Beside the L-FB, simple but effective designs for the interaction point feedback and cost reduction options for the quadrupole stabilisation are presented. For the design of all these feedback systems models of the ground motion influence on different beam parameters such as beam offset, beam size and luminosity have been derived by adapting and extending existent models. To design, improve and validate the ground motion mitigation methods, a simulation framework was set up, which includes a ground motion generator, beam tracking, beam-beam interaction and all mitigation methods. The simulations show that the ground motion mitigation methods can efficiently preserve the CLIC luminosity. Due to our

  8. Proton beam therapy control system

    Science.gov (United States)

    Baumann, Michael A.; Beloussov, Alexandre V.; Bakir, Julide; Armon, Deganit; Olsen, Howard B.; Salem, Dana

    2008-07-08

    A tiered communications architecture for managing network traffic in a distributed system. Communication between client or control computers and a plurality of hardware devices is administered by agent and monitor devices whose activities are coordinated to reduce the number of open channels or sockets. The communications architecture also improves the transparency and scalability of the distributed system by reducing network mapping dependence. The architecture is desirably implemented in a proton beam therapy system to provide flexible security policies which improve patent safety and facilitate system maintenance and development.

  9. Dynamical behaviour of Liu system with time delayed feedback

    Institute of Scientific and Technical Information of China (English)

    Qian Qin; Wang Lin; Ni Qiao

    2008-01-01

    This paper investigates the dynamical behaviour of the Liu system with time delayed feedback.Two typical situations are considered and the effect of time-delay parameter on the dynamics of the system is discussed.It is shown that the Liu system with time delayed feedback may exhibit interesting and extremely rich dynamical behaviour.The evolution of the dynamics is shown to be complex with varying time-delay parameter.Moreover,the strange attractor like 'wormhole' is detected via numerical simulations.

  10. Performance of the transverse coupled-bunch feedback system in the SRRC

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, K.T.; Kuo, C.C.; Kuo, C.H.; Lin, K.K.; Ueng, T.S.; Weng, W.T.

    1996-10-01

    A transverse feedback system has been implemented and commissioned in the SRRC storage ring to suppress transverse coupled-bunch oscillations of the electron beam. The system includes transverse oscillation detectors, notch filter, baseband quadrature processing circuitry, power amplifiers, and kickers. To control a large number of transverse coupled-bunch modes, the system is broad-band, bunch-by- bunch in nature. Because the system is capable of bunch-by-bunch correction, it can also be useful for suppressing instabilities introduced by ions. The sextupole strength was then reduced to improve dynamic aperture and hence lifetime of the storage ring.

  11. Plasma flute oscillation stabilization by means of a feedback system

    International Nuclear Information System (INIS)

    Considered in this paper is the possibility of stabilizing flute oscillations of plasma in right traps with the aid of a feedback system involving measurement of the radial component of a disturbed electric field. It is assumed that the plasma is confined along the Z axis, while transducers and suppressing electrodes may be arranged at different distances from the axis of the system. For the flute oscillation equation in which the finite length of the plasma along the magnetic field is taken into account, an eigenvalue problem is examined with boundary conditions simulating the feedback system. It is assumed that the transfer factor is independent of frequency and that the azimuthal modes are separated. Numerical methods are used to study effects of the longitudinal dimensions of plasma, magnetic field gradient and vacuum region size on stability. Oscillation stability boundaries have been derived, depending on the feedback factor values and the transducer location

  12. Feedback Control Systems Loop Shaping Design with Practical Considerations

    Science.gov (United States)

    Kopsakis, George

    2007-01-01

    This paper describes loop shaping control design in feedback control systems, primarily from a practical stand point that considers design specifications. Classical feedback control design theory, for linear systems where the plant transfer function is known, has been around for a long time. But it s still a challenge of how to translate the theory into practical and methodical design techniques that simultaneously satisfy a variety of performance requirements such as transient response, stability, and disturbance attenuation while taking into account the capabilities of the plant and its actuation system. This paper briefly addresses some relevant theory, first in layman s terms, so that it becomes easily understood and then it embarks into a practical and systematic design approach incorporating loop shaping design coupled with lead-lag control compensation design. The emphasis is in generating simple but rather powerful design techniques that will allow even designers with a layman s knowledge in controls to develop effective feedback control designs.

  13. Velocity Feedback Control of a Mechatronics System

    OpenAIRE

    Ayman A. Aly

    2013-01-01

    Increasing demands in performance and quality make drive systems fundamental parts in the progressive automation of industrial process. The analysis and design of Mechatronics systems are often based on linear or linearized models which may not accurately represent the servo system characteristics when the system is subject to inputs of large amplitude. The impact of the nonlinearities of the dynamic system and its stability needs to be clarified.The objective of this paper is to present a n...

  14. Experience feedback system of nuclear power plant under construction

    International Nuclear Information System (INIS)

    The Experience Feedback System of Hainan Nuclear Power Plant under construction, which is a typical EPC nuclear power project, is introduced in the paper. And the good practice of the system set a good example for those NPPs under construction in China. (authors)

  15. Note: Design of a laser feedback interferometer with double diffraction system

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Dongmei, E-mail: guodongmei@njnu.edu.cn; Wang, Ming [Jiangsu Key Laboratory on Opto-Electronic Technology, School of Physical Science and Technology, Nanjing Normal University, Nanjing 210023 (China)

    2015-09-15

    A novel laser feedback interferometer with double diffraction system is proposed in this paper. A beam emitted from the laser is incident onto a transmission grating. The mth order beam is vertically reflected by a mirror and diffracted again by the grating. The double-diffracted beam returns into the laser cavity and mixes with the light inside the active cavity, thus generating a modulation of both the amplitude and the frequency of the lasing field. Theoretical analysis and experimental observations show that the output signal of the proposed system depends on the grating pitch and the direction of the phase movement can be obtained from inclination of the interference signal. It provides a potential displacement sensor with high stability and quite a compact configuration.

  16. Transfer Function Model of Multirate Feedback Control Systems

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the suitably defined multivariable version of Krancoperators and the extended input and output vectors, the multirate sampling plant is transformed to a equivalent time invariant single rate one, then the transfer function model of the multivariable multirate sampling plant is obtained. By combining this plant model with the time invariant description of the multirate controller in terms of extended vectors, the closed-loop transfer function model of the multirate feedback control system can be determinated. This transfer function model has a very simple structure, and can be used as a basis for the analysis and synthesis of the multirate sampling feedback control systems in the frequency domain.

  17. KTeV beam systems design report

    Energy Technology Data Exchange (ETDEWEB)

    Bocean, V.; Childress, S.; Coleman, R. [and others

    1997-09-01

    The primary and secondary beams for the KTeV experiments E799-II and E832 are discussed. The specifications are presented and justified. The technical details of the implementation of the primary beam transport and stability are detailed. The target, beam dump, and radiation safety issues are discussed. The details of the collimation system for the pair of secondary beams are presented.

  18. KTeV beam systems design report

    International Nuclear Information System (INIS)

    The primary and secondary beams for the KTeV experiments E799-II and E832 are discussed. The specifications are presented and justified. The technical details of the implementation of the primary beam transport and stability are detailed. The target, beam dump, and radiation safety issues are discussed. The details of the collimation system for the pair of secondary beams are presented

  19. Stabilization of elastic systems by collocated feedback

    CERN Document Server

    Ammari, Kaïs

    2015-01-01

    By introducing a new stabilization methodology, this book characterizes the stability of a certain class of systems. The stability (exponential, polynomial, or weaker) for the closed loop problem is reduced to an observability estimate for the corresponding uncontrolled system combined with a boundedness property of the transfer function of the associated open loop system. A similar strategy is applied to systems where a delay term is added. The book concludes with many concrete examples. This book is addressed to graduate students in mathematics or engineering and also to researchers with an interest in stabilization and control systems governed by partial differential equations.

  20. Fuzzy Feedback Scheduling of Resource-Constrained Embedded Control Systems

    CERN Document Server

    Xia, Feng; Tian, Yu-Chu; Tade, Moses; Dong, Jinxiang

    2008-01-01

    The quality of control (QoC) of a resource-constrained embedded control system may be jeopardized in dynamic environments with variable workload. This gives rise to the increasing demand of co-design of control and scheduling. To deal with uncertainties in resource availability, a fuzzy feedback scheduling (FFS) scheme is proposed in this paper. Within the framework of feedback scheduling, the sampling periods of control loops are dynamically adjusted using the fuzzy control technique. The feedback scheduler provides QoC guarantees in dynamic environments through maintaining the CPU utilization at a desired level. The framework and design methodology of the proposed FFS scheme are described in detail. A simplified mobile robot target tracking system is investigated as a case study to demonstrate the effectiveness of the proposed FFS scheme. The scheme is independent of task execution times, robust to measurement noises, and easy to implement, while incurring only a small overhead.

  1. Hardware design and implementation of the closed-orbit feedback system at APS

    International Nuclear Information System (INIS)

    The Advanced Photon Source (APS) storage ring will utilize a closed-orbit feedback system in order to produce a more stable beam. The specified orbit measurement resolution is 25 microns for global feedback and 1 micron for local feedback. The system will sample at 4 kHz and provide a correction bandwidth of 100 Hz. At this bandwidth, standard rf BPMs will provide a resolution of 0.7 micron, while specialized miniature BPMs positioned on either side of the insertion devices for local feedback will provide a resolution of 0.2 micron (1). The measured BPM noise floor for standard BPMs is 0.06 micron per root hertz mA. Such a system has been designed, simulated, and tested on a small scale (2). This paper covers the actual hardware design and layout of the entire closed-loop system. This includes commercial hardware components, in addition to many components designed and built in-house. The paper will investigate the large-scale workings of all these devices, as well as an overall view of each piece of hardware used

  2. Decentralized-feedback pole placement of linear systems

    Science.gov (United States)

    Wang, X.; Martin, C. F.; Gilliam, D.; Byrnes, C. I.

    1992-01-01

    A projectile product spaces model is used to analyze decentralized systems. The degree of the pole placement map is computed. The conditions under which the degree is odd are also given. Twin lift systems are studied. It is proved that the poles of a twin lift system can be assigned to any values by local static and local dynamic feedback laws if and only if the system is jointly controllable.

  3. High power neutral beam systems

    International Nuclear Information System (INIS)

    Spurred by the requirement to supply megawatts of power to heat magnetically confined plasmas to temperatures of interest for fusion research, a new class of low energy, high power accelerators termed neutral beam injectors has been developed. Industry has played an important role in building upon technology advances at the national laboratories to engineer neutral beam injectors to meet the needs of specific users. A brief retrospective of the field is presented, with emphasis upon one particular application, that of DIII-D, a large tokamak at General Atomics. In this instance, the role of industry has been especially extensive because the user/system integrator is itself an industrial concern. 4 refs., 7 figs., 2 tabs

  4. Feedback Improvement in Automatic Program Evaluation Systems

    Science.gov (United States)

    Skupas, Bronius

    2010-01-01

    Automatic program evaluation is a way to assess source program files. These techniques are used in learning management environments, programming exams and contest systems. However, use of automated program evaluation encounters problems: some evaluations are not clear for the students and the system messages do not show reasons for lost points.…

  5. Requirements of CLIC Beam Loss Monitoring System

    CERN Document Server

    Sapinski, M; Holzer, EB; Jonker, M; Mallows, S; Otto, T; Welsch, C

    2010-01-01

    The Compact Linear Collider (CLIC) [1] is a proposed multi-TeV linear electron-positron collider being designed by a world-wide collaboration. It is based on a novel twobeam acceleration scheme in which two beams (drive and main beam) are placed in parallel to each other and energy is transferred from the drive beam to the main one. Beam losses on either of them can have catastrophic consequences for the machine, because of high intensity (drive beam) or high energy and small emittance (main beam). In the framework of machine protection, a Beam Loss Monitoring (BLM) system has to be put in place. This paper discusses the requirements for the beam loss system in terms of detector sensitivity, resolution, dynamic range and ability to distinguish losses originating from various sources. The two-beam module where the protection from beam losses is particularly challenging and important, is studied.

  6. PUMPED LASER SYSTEM USING FEEDBACK TO PUMP MEANS

    DEFF Research Database (Denmark)

    2008-01-01

    A laser system according to the invention comprises pump generating means (xO2, xO3) for generating at least a first and a second, preferably focused, pump beam, and lasing means (xO6, xO7) for emitting radiation by being appropriately pumped. The lasing means (xO6, xO7) is disposed in a first...... resonator so as to receive the first pump beam in order to generate a first beam (x21) having a first frequency, and the lasing means (xO6, xO7) is disposed in a second resonator so as to receive the second pump beam in order to generate a second beam (x22) having a second frequency. At least one Q...... fed back to a regulation system (x14), said regulation system (x14) controlling said pump generating means (xO2, xO3)....

  7. Operating experience feedback report - Air systems problems

    International Nuclear Information System (INIS)

    This report highlights significant operating events involving observed or potential failures of safety-related systems in U.S. plants that resulted from degraded or malfunctioning non-safety grade air systems. Based upon the evaluation of these events, the Office for Analysis and Evaluation of Operational Data (AEOD) concludes that the issue of air systems problems is an important one which requires additional NRC and industry attention. This report also provides AEOD's recommendations for corrective actions to deal with the issue. (author)

  8. Output feedback regulator design for jet engine control systems

    Science.gov (United States)

    Merrill, W.

    1977-01-01

    A multivariable control design procedure based on the output feedback regulator formulation is described and applied to an F100 turbofan engine model. Full order model dynamics, are incorporated in the example design. The effect of actuator dynamics on closed loop performance is investigated. Also, the importance of turbine inlet temperature as an element of the dynamic feedback is studied. Step responses are given to indicate the improvement in system performance with this control. Calculation times for all experiments are given in CPU seconds for comparison purposes.

  9. Configuration and Validation of the LHC Beam Loss Monitoring System

    CERN Document Server

    Zamantzas, C; Emery, J; Fitzek, J; Follin, F; Jackson, S; Kain, V; Kruk, G; Misiowiec, M; Roderick, C; Sapinski, M

    2009-01-01

    The LHC Beam Loss Monitoring (BLM) system is one of the most complex instrumentation systems deployed in the LHC. As well as protecting the machine, the system is also used as a means of diagnosing machine faults, and providing feedback of losses to the control room and several systems such as the Collimation, the Beam Dump and the Post-Mortem. The system has to transmit and process signals from over 4’000 monitors, and has approaching 3 million configurable parameters. This paper describes the types of configuration data needed, the means used to store and deploy all the parameters in such a distributed system and how operators are able to alter the operating parameters of the system, particularly with regard to the loss threshold values. The various security mechanisms put in place, both at the hardware and software level, to avoid accidental or malicious modification of these BLM parameters are also shown for each case.

  10. Swing Damping for Helicopter Slung Load Systems using Delayed Feedback

    DEFF Research Database (Denmark)

    Bisgaard, Morten; la Cour-Harbo, Anders; Bendtsen, Jan Dimon

    2009-01-01

    This paper presents the design and verification of a swing reducing controller for helicopter slung load systems using intentional delayed feedback. It is intended for augmenting a trajectory tracking helicopter controller and thereby improving the slung load handing capabilities for autonomous h...

  11. Time-optimal feedback control for linear systems

    International Nuclear Information System (INIS)

    The paper deals with the results of qualitative investigations of the time-optimal feedback control for linear systems with constant coefficients. In the first section, after some definitions and notations, two examples are given and it is shown that even the time-optimal control problem for linear systems with constant coefficients which looked like ''completely solved'' requires a further qualitative investigation of the stability to ''permanent perturbations'' of optimal feedback control. In the second section some basic results of the linear time-optimal control problem are reviewed. The third section deals with the definition of Boltyanskii's ''regular synthesis'' and its connection to Filippov's theory of right-hand side discontinuous differential equations. In the fourth section a theorem is proved concerning the stability to perturbations of time-optimal feedback control for linear systems with scalar control. In the last two sections it is proved that, if the matrix which defines the system has only real eigenvalues or is three-dimensional, the time-optimal feedback control defines a regular synthesis and therefore is stable to perturbations. (author)

  12. Combined feedforward and feedback control of end milling system

    Directory of Open Access Journals (Sweden)

    F. Cus

    2011-03-01

    Full Text Available Purpose: Purpose of this paper. An intelligent control system is presented that uses a combination of feedforward and feedback for cutting force control in end milling.Design/methodology/approach: The network is trained by the feedback output that is minimized during training and most control action for disturbance rejection is finally performed by the rapid feedforward action of the network.Findings: The feedback controller corrects for errors caused by external disturbances. The feedforward controller is an artificial neural network (ANN which approximates the inverse dynamics of the machining process.Research limitations/implications: The dynamic architecture of the neural controller is chosen, and the methods for delay time treatment and training network on line are investigated. The controller was designed and tested using a simulator model of the milling process that includes feed drive model and cutting dynamics simulator.Practical implications: An application to cutting force control in end-milling is used to prove the effectiveness of the control scheme and the experiments shows that the dynamic performance of the cutting force control is greatly improved by this neural combined control system.Originality/value: New combined feedforward and feedback control system of end milling system is developed and tested by many experiments. Also a comprehensive user-friendly software package has been developed to monitor the optimal cutting parameters during machining

  13. Design of multivariable feedback control systems via spectral assignment

    Science.gov (United States)

    Mielke, R. R.; Tung, L. J.; Marefat, M.

    1983-01-01

    The applicability of spectral assignment techniques to the design of multivariable feedback control systems was investigated. A fractional representation design procedure for unstable plants is presented and illustrated with an example. A computer aided design software package implementing eigenvalue/eigenvector design procedures is described. A design example which illustrates the use of the program is explained.

  14. Cross-Layer Adaptive Feedback Scheduling of Wireless Control Systems

    Directory of Open Access Journals (Sweden)

    Jinxiang Dong

    2008-07-01

    Full Text Available There is a trend towards using wireless technologies in networked control systems. However, the adverse properties of the radio channels make it difficult to design and implement control systems in wireless environments. To attack the uncertainty in available communication resources in wireless control systems closed over WLAN, a cross-layer adaptive feedback scheduling (CLAFS scheme is developed, which takes advantage of the co-design of control and wireless communications. By exploiting crosslayer design, CLAFS adjusts the sampling periods of control systems at the application layer based on information about deadline miss ratio and transmission rate from the physical layer. Within the framework of feedback scheduling, the control performance is maximized through controlling the deadline miss ratio. Key design parameters of the feedback scheduler are adapted to dynamic changes in the channel condition. An eventdriven invocation mechanism for the feedback scheduler is also developed. Simulation results show that the proposed approach is efficient in dealing with channel capacity variations and noise interference, thus providing an enabling technology for control over WLAN.

  15. Open Problems on Information and Feedback Controlled Systems

    OpenAIRE

    Manuel Feito; Cao, Francisco J.

    2012-01-01

    Feedback or closed-loop control allows dynamical systems to increase their performance up to a limit imposed by the second law of thermodynamics. It is expected that within this limit, the system performance increases as the controller uses more information about the system. However, despite the relevant progresses made recently, a general and complete formal development to justify this statement using information theory is still lacking. We present here the state-of-the-art and the main open...

  16. Bifurcation Analysis of a Discrete Logistic System with Feedback Control

    Institute of Scientific and Technical Information of China (English)

    WU Dai-yong

    2015-01-01

    The paper studies the dynamical behaviors of a discrete Logistic system with feedback control. The system undergoes Flip bifurcation and Hopf bifurcation by using the center manifold theorem and the bifurcation theory. Numerical simulations not only illustrate our results, but also exhibit the complex dynamical behaviors of the system, such as the period-doubling bifurcation in periods 2, 4, 8 and 16, and quasi-periodic orbits and chaotic sets.

  17. On stability theory. [of nonlinear feedback control systems

    Science.gov (United States)

    Safonov, M. G.; Athans, M.

    1979-01-01

    It is found that under mild assumptions, feedback system stability can be concluded if one can 'topologically separate' the infinite-dimensional function space containing the system's dynamical input-output relations into two regions, one region containing the dynamical input-output relation of the 'feedforward' element of the system and the other region containing the dynamical output-input relation of the 'feedback' element. Nonlinear system stability criteria of both the input-output type and the state-space (Liapunov) type are interpreted in this context. The abstract generality and conceptual simplicity afforded by the topological separation perspective clarifies some of the basic issues underlying stability theory and serves to suggest improvements in existing stability criteria. A generalization of Zames' (1966) conic-relation stability criterion is proved, laying the foundation for improved multivariable generalizations of the frequency-domain circle stability criterion for nonlinear systems.

  18. Simulation of e-cloud driven instability and its attenuation using a simulated feedback system in the CERN SPS

    Energy Technology Data Exchange (ETDEWEB)

    Vay, J.-L.; Furman, M. A.

    2010-12-13

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the single-bunch instabilities is under active development. We present the latest improvements to the WARP-POSINST simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS. Simulations using an idealized feedback system exhibit adequate mitigation of the instability providing that the cutoff of the feedback bandwidth is at or above 450 MHz. Artifacts from numerical noise of the injected distribution of electrons in the modeling of portions of bunch trains are discussed, and benchmarking of WARP against POSINST and HEADTAIL are presented.

  19. Simulation of e-cloud driven instability and its attenuation using a simulated feedback system in the CERN SPS

    International Nuclear Information System (INIS)

    Electron clouds have been shown to trigger fast growing instabilities on proton beams circulating in the SPS, and a feedback system to control the single-bunch instabilities is under active development. We present the latest improvements to the WARP-POSINST simulation framework and feedback model, and its application to the self-consistent simulations of two consecutive bunches interacting with an electron cloud in the SPS. Simulations using an idealized feedback system exhibit adequate mitigation of the instability providing that the cutoff of the feedback bandwidth is at or above 450 MHz. Artifacts from numerical noise of the injected distribution of electrons in the modeling of portions of bunch trains are discussed, and benchmarking of WARP against POSINST and HEADTAIL are presented.

  20. A betatron tune measurement system based on bunch-by-bunch transverse feedback at the Duke storage ring

    Science.gov (United States)

    Xu, Wei; Z. Wu, W.; Li, Jing-Yi; He, Duo-Hui; K. Wu, Y.

    2013-07-01

    To combat electron beam instabilities, a digital bunch-by-bunch transverse feedback (TFB) system has been developed for the Duke storage ring. While it is capable of suppressing transverse beam instabilities for multibunch operation, the TFB system has not been needed for typical operation of the Duke storage ring. To explore the great potential of this system, we have developed beam diagnostic techniques using the TFB, in particular, the TFB based tune measurement techniques. The tune measurement technique allows us to conduct fast chromaticity measurements, compared with the existing chromaticity measurement system using a network analyzer. This new tune measurement system also enables us to measure the bunch tune for multibunch operation of the Duke storage ring. With the TFB based tune measurement system, we have studied the tune stability of the electron beam in the Duke storage ring. This tune system has also been used to calibrate the tune knob for the Duke storage ring.

  1. LHC beam instrumentation detectors and acquisition systems

    International Nuclear Information System (INIS)

    An overview of some of the detectors and acquisition systems being developed for measuring and controlling beam parameters in the LHC. The two largest systems concern the measurement of beam position, with over 1000 monitors, and beam loss, with over 3000 monitors. For the beam position system a novel wide band time normaliser has been developed to allow bunch-by-bunch 40MHz acquisitions with a dynamic range greater than 30dB and an overall linearity of better than 1%. Also mentioned will be the acquisition system for the fast beam current transformers and the development of CdTe detectors for luminosity monitoring. [author

  2. Modeling mutual feedback between users and recommender systems

    Science.gov (United States)

    Zeng, An; Yeung, Chi Ho; Medo, Matúš; Zhang, Yi-Cheng

    2015-07-01

    Recommender systems daily influence our decisions on the Internet. While considerable attention has been given to issues such as recommendation accuracy and user privacy, the long-term mutual feedback between a recommender system and the decisions of its users has been neglected so far. We propose here a model of network evolution which allows us to study the complex dynamics induced by this feedback, including the hysteresis effect which is typical for systems with non-linear dynamics. Despite the popular belief that recommendation helps users to discover new things, we find that the long-term use of recommendation can contribute to the rise of extremely popular items and thus ultimately narrow the user choice. These results are supported by measurements of the time evolution of item popularity inequality in real systems. We show that this adverse effect of recommendation can be tamed by sacrificing part of short-term recommendation accuracy.

  3. Modeling mutual feedback between users and recommender systems

    CERN Document Server

    Zeng, An; Medo, Matus; Zhang, Yi-Cheng

    2015-01-01

    Recommender systems daily influence our decisions on the Internet. While considerable attention has been given to issues such as recommendation accuracy and user privacy, the long-term mutual feedback between a recommender system and the decisions of its users has been neglected so far. We propose here a model of network evolution which allows us to study the complex dynamics induced by this feedback, including the hysteresis effect which is typical for systems with non-linear dynamics. Despite the popular belief that recommendation helps users to discover new things, we find that the long-term use of recommendation can contribute to the rise of extremely popular items and thus ultimately narrow the user choice. These results are supported by measurements of the time evolution of item popularity inequality in real systems. We show that this adverse effect of recommendation can be tamed by sacrificing part of short-term recommendation accuracy.

  4. Linear feedback control, adaptive feedback control and their combination for chaos (lag) synchronization of LC chaotic systems

    International Nuclear Information System (INIS)

    In this paper, we study chaos (lag) synchronization of a new LC chaotic system, which can exhibit not only a two-scroll attractor but also two double-scroll attractors for different parameter values, via three types of state feedback controls: (i) linear feedback control; (ii) adaptive feedback control; and (iii) a combination of linear feedback and adaptive feedback controls. As a consequence, ten families of new feedback control laws are designed to obtain global chaos lag synchronization for τ < 0 and global chaos synchronization for τ = 0 of the LC system. Numerical simulations are used to illustrate these theoretical results. Each family of these obtained feedback control laws, including two linear (adaptive) functions or one linear function and one adaptive function, is added to two equations of the LC system. This is simpler than the known synchronization controllers, which apply controllers to all equations of the LC system. Moreover, based on the obtained results of the LC system, we also derive the control laws for chaos (lag) synchronization of another new type of chaotic system

  5. Output Feedback Control for a Class of Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    Keylan Alimhan; Hiroshi Inaba

    2006-01-01

    This paper studies the global stabilization problem by an output controller for a family of uncertain nonlinear systems satisfying some relaxed triangular-type conditions and with dynamics which may not be exactly known. Using a feedback domination design method, we explicitly construct a dynamic output compensator which globally stabilizes such an uncertain nonlinear system. The usefulness of our result is illustrated with an example.

  6. Autonomous learning by simple dynamical systems with delayed feedback

    Science.gov (United States)

    Kaluza, Pablo; Mikhailov, Alexander S.

    2014-09-01

    A general scheme for the construction of dynamical systems able to learn generation of the desired kinds of dynamics through adjustment of their internal structure is proposed. The scheme involves intrinsic time-delayed feedback to steer the dynamics towards the target performance. As an example, a system of coupled phase oscillators, which can, by changing the weights of connections between its elements, evolve to a dynamical state with the prescribed (low or high) synchronization level, is considered and investigated.

  7. Non-Linear Dynamic Deformation of a Piezothermoelastic Laminate with Feedback Control System

    Directory of Open Access Journals (Sweden)

    Masayuki Ishihara

    2014-03-01

    Full Text Available We study the control of free vibration with large amplitude in a piezothermoelastic laminated beam subjected to a uniform temperature with a feedback control system. The analytical model is the symmetrically cross-ply laminated beam composed of the elastic and piezoelectric layers. On the basis of the von Kármán strain and the classical laminate theory, the governing equations for the dynamic behavior are derived. The dynamic behavior is detected by the electric current in the sensor layer through the direct piezoelectric effect. The electric voltage with the magnitude of the current multiplied by the gain is applied to the actuator layer to constitute a feedback control system. The governing equations are reduced by the Galerkin method to a Liénard equation with respect to the representative deflection, and the equation is found to be dependent on the gain and the configuration of the actuator. By introducing the Liénard's phase plane, the equation is analyzed geometrically, and the essential characteristics of the beam and stabilization of the dynamic deformation are demonstrated.

  8. On reliable control system designs with and without feedback reconfigurations

    Science.gov (United States)

    Birdwell, J. D.; Castanon, D. A.; Athans, M.

    1979-01-01

    This paper contains an overview of a theoretical framework for the design of reliable multivariable control systems, with special emphasis on actuator failures and necessary actuator redundancy levels. Using a linear model of the system, with Markovian failure probabilities and quadratic performance index, an optimal stochastic control problem is posed and solved. The solution requires the iteration of a set of highly coupled Riccati-like matrix difference equations; if these converge one has a reliable design; if they diverge, the design is unreliable, and the system design cannot be stabilized. In addition, it is shown that the existence of a stabilizing constant feedback gain and the reliability of its implementation is equivalent to the convergence properties of a set of coupled Riccati-like matrix difference equations. In summary, these results can be used for offline studies relating the open loop dynamics, required performance, actuator mean time to failure, and functional or identical actuator redundancy, with and without feedback gain reconfiguration strategies.

  9. Stability and Bifurcation in Magnetic Flux Feedback Maglev Control System

    Directory of Open Access Journals (Sweden)

    Wen-Qing Zhang

    2013-01-01

    Full Text Available Nonlinear properties of magnetic flux feedback control system have been investigated mainly in this paper. We analyzed the influence of magnetic flux feedback control system on control property by time delay and interfering signal of acceleration. First of all, we have established maglev nonlinear model based on magnetic flux feedback and then discussed hopf bifurcation’s condition caused by the acceleration’s time delay. The critical value of delayed time is obtained. It is proved that the period solution exists in maglev control system and the stable condition has been got. We obtained the characteristic values by employing center manifold reduction theory and normal form method, which represent separately the direction of hopf bifurcation, the stability of the period solution, and the period of the period motion. Subsequently, we discussed the influence maglev system on stability of by acceleration’s interfering signal and obtained the stable domain of interfering signal. Some experiments have been done on CMS04 maglev vehicle of National University of Defense Technology (NUDT in Tangshan city. The results of experiments demonstrate that viewpoints of this paper are correct and scientific. When time lag reaches the critical value, maglev system will produce a supercritical hopf bifurcation which may cause unstable period motion.

  10. Spiral kicker for the beam abort system

    Energy Technology Data Exchange (ETDEWEB)

    Martin, R.L.

    1983-01-01

    A brief study was carried out to determine the feasibility of a special kicker to produce a damped spiral beam at the beam dump for the beam abort system. There appears to be no problem with realizing this concept at a reasonably low cost.

  11. Observer-based H-infinity output feedback control with feedback gain and observer gain variations for Delta operator system

    Institute of Scientific and Technical Information of China (English)

    Ruiquan LIN; Fuwen YANG; Renchong PENG

    2009-01-01

    Considering that the controller feedback gain and the observer gain are of additive norm-bounded variations, a design method of observer-based H-infinity output feedback controller for uncertain Delta operator systems is proposed in this paper. A sufficient condition of such controllers is presented in linear matrix inequality (LMI) forms. A numerical example is then given to illustrate the effectiveness of this method, that is, the obtained controller guarantees the closed-loop system asymptotically stable and the expected H-infinity performance even if the controller feedback gain and the observer gain are varied.

  12. Parameterized design of nonlinear feedback controllers for servo positioning systems

    Institute of Scientific and Technical Information of China (English)

    Cheng Guoyang; Jin Wenguang

    2006-01-01

    To achieve fast, smooth and accurate set point tracking in servo positioning systems, a parameterized design of nonlinear feedback controllers is presented, based on a so-called composite nonlinear feedback (CNF) control technique. The controller designed here consists of a linear feedback part and a nonlinear part. The linear part is responsible for stability and fast response of the closed-loop system. The nonlinear part serves to increase the damping ratio of closed-loop poles as the controlled output approaches the target reference. The CNF control brings together the good points of both the small and the large damping ratio cases, by continuously scheduling the damping ratio of the dominant closed-loop poles and thus has the capability for superior transient performance, i.e. a fast output response with low overshoot. In the presence of constant disturbances, an integral action is included so as to remove the static bias. An explicitly parameterized controller is derived for servo positioning systems characterized by second-order model. Practical application in a micro hard disk drive servo system is then presented, together with some discussion of the rationale and characteristics of such design. Simulation and experimental results demonstrate the effectiveness of this control design methodology.

  13. Mitigation of ground motion effects via feedback systems in the Compact Linear Collider

    CERN Document Server

    Pfingstner, Jürgen; Schmickler, Hermann; Schulte, Daniel

    The Compact Linear Collider (CLIC) is a future multi-TeV electron positron collider, which is currently being designed at CERN. To achieve its ambitious goals, CLIC has to produce particle beams of the highest quality, which makes the accelerator very sensitive to ground motion. Four mitigation methods have been foreseen by the CLIC design group to cope with the feasibility issue of ground motion. This thesis is concerned with the design of one of these mitigation methods, named linac feedback (L-FB), but also with the simultaneous simulation and validation of all mitigation methods. Additionally, a technique to improve the quality of the indispensable system knowledge has been developed. The L-FB suppresses beam oscillations along the accelerator. Its design is based on the decoupling of the overall accelerator system into independent channels. For each channel an individual compensator is found with the help of a semi- automatic control synthesis procedure. This technique allows the designer to incorporate ...

  14. Transverse feedback systems for the PEP-II B-factory

    International Nuclear Information System (INIS)

    Growth rates of coherent beam oscillations are faster than the natural damping mechanisms for the parameters of the PEP-II B-factory storage rings at nominal currents, even with damping of cavity higher order modes (HOM's). With 165 8 bunches separated by 4.2 ns, and a large current of up to 3A (2.14 A nominal in the low energy ring), many coupled-bunch modes are excited by the resistive wall impedance and cavity higher order mode impedance. Fastest growth times of transverse rigid-bunch modes of approximately 300 ps are expected, two orders of magnitude faster than the radiation damping time. We will provide broadband, bunch-by-bunch feedback to suppress this coherent motion of the beam. Experience gained with a prototype system, installed and successfully operating at the LBNL Advanced Light Source (ALS), has been used extensively in developing the design of the PEP-II systems

  15. Decentralized stabilization of complex systems with delayed feedback

    Czech Academy of Sciences Publication Activity Database

    Bakule, Lubomír; de la Sen, M.; Papík, Martin; Rehák, Branislav

    Shanghai: International Federation of Automatic Control , 2013, s. 31-36. (Large Scale Complex Systems Theory and Applications. Volume 13). ISBN 978-3-902823-39-7. ISSN 1474-6670. [IFAC Symposium of Large Scale Complex Systems /13./ (LSS 2013). Shanghai (CN), 07.07.2013-10.07.2013] R&D Projects: GA ČR GA13-02149S; GA MŠk(CZ) LG12014; GA MŠk(CZ) LG12008 Institutional support: RVO:67985556 Keywords : decentralized control * symmetric interconnected systems * delayed feedback Subject RIV: BC - Control Systems Theory http://library.utia.cas.cz/separaty/2013/AS/bakule-0393028.pdf

  16. Multiple-pattern stability in a photorefractive feedback system

    DEFF Research Database (Denmark)

    Schwab, M.; Denz, C.; Saffman, M.

    1999-01-01

    diffraction lengths. For the same values of the control parameters square, rectangular, or squeezed hexagonal patterns are found alternating in time. Besides these pure states, we found a number of different mixed-pattern states. We review the linear stability analysis for this system and show that the......We report on the observation of a multiple-pattern stability region in a photorefractive single-feedback system. Whereas hexagonal patterns are predominant for feedback with positive diffraction length we show that a variety of stable non-hexagonal patterns are generated for certain negative...... special shape of the threshold curves in the investigated parameter region gives a first explanation for the occurrence of a multiple-pattern region....

  17. Digital bunch-by-bunch transverse feedback system at SSRF

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In order to suppress multi-bunch couple instabilities caused by transverse impedance, a bunch-by-bunch transverse feedback system based on a FPGA digital processor is commissioned at SSRF storage ring. The RF front end has two COD pre-rejected attenuators for increasing the system arrangement and signal noise ratio, and the 3*RF Local signal comes from the BPM’s sum signal using a FIR filter for avoiding the effect of longitudinal oscillation. The digital processor receives the coupled horizontal and vertical oscillation signals in the base band and transforms the coupled signals to the horizontal and vertical feedback signals with two series double-zeroes FIR filters. A matlab GUI is applied for producing the FIR coefficients when the tune is shifted. The horizontal and vertical Kickers have a special design for increasing the shunt impedance. Then the multi-bunch instabilities are suppressed respectively and the minimum damping time is about 0.4 ms.

  18. Integration of the Longitudinal Feedback System in NSRRC

    International Nuclear Information System (INIS)

    An operation version of longitudinal feedback baseband processing electronics was implemented. The system consists of a bunch phase detector, a 500-MS/s analog-to-digital converter and demultiplexer module (ADC/DEMUX), DSP modules, a digital-to-analog converter and multiplexer module (DAC/MUX), and an RF modulator. The ADC/DEMUX unit has a fast ADC that digitizes the bunch phase signal. The down-sampled phase error data of each bunch are then distributed to the DSP boards to perform filtering and applied control rule. In the DAC/MUX, bunch kick signals are converted into analog signals for bunch phase feedback. Design and implementation of the system will be summarized in this report

  19. Design and Simulation of PMSM Feedback Linearization Control System

    OpenAIRE

    Song, Xiao-jing

    2013-01-01

    With the theory of AC adjustable speed as well as a new control theory research is unceasingly thorough, the permanent magnet synchronous motor control system requires high precision of control and high reliability of the occasion, access to a wide range of applications, in the modern AC motor has play a decisive role position. Based on the deep research on the feedback linearization technique based on, by choosing appropriate state transformation and control transform, PMSM model input outpu...

  20. Digital feedback system using μTCA for DRFS

    International Nuclear Information System (INIS)

    The test of distributed RF scheme (DRFS) for ILC was performed at the superconducting RF test facility in KEK (KEK-STF). The vector-sum control for two cavities was done by using the digital feedback system using the μTCA. A correction of a large sag due to electrical power source and IIR filter which is also applied as a cavity simulator was installed. The measurement of field stability and the performance are reported. (author)

  1. Challenges in the Implementation of Measurement Feedback Systems.

    Science.gov (United States)

    de Jong, Kim

    2016-05-01

    This commentary on the articles published in the special section on the development and implementation of measurement feedback systems (MFSs) discusses three challenging themes in the process of MFS implementation: design and planning, organizational context, and sustainability and unintended consequences. It is argued that the implementation of MFSs is complex, but is an important step in improving outcomes in routine care for children and young persons. PMID:26518779

  2. Virtual Chimera States for Delayed-Feedback Systems

    OpenAIRE

    Larger, Laurent; PENKOVSKYI, Bogdan; Maistrenko, Yuri

    2013-01-01

    International audience Time-delayed systems are found to display remarkable temporal patterns the dynamics of which split into regular and chaotic components repeating at the interval of a delay. This novel long-term behavior for delay dynamics results from strongly asymmetric nonlinear delayed feedback driving a highly damped harmonic oscillator dynamics. In the corresponding virtual space-time representation, the behavior is found to develop as a chimeralike state, a new paradigmatic obj...

  3. Study of an accelerating superconducting module and its feedback loop systems for the MYRRHA project

    International Nuclear Information System (INIS)

    The MYRRHA ( Multi-purpose hybrid Research Reactor for High-tech Applications ) project aims at constructing an accelerator driven system (ADS) demonstrator (50 a 100 MWth) to explore the feasibility of nuclear waste transmutation. Such a subcritical reactor requires an extremely reliable accelerator which delivers a CW high power protons beam (600 MeV, 4 mA). The reference solution for this machine is a superconducting linear accelerator. This thesis presents the work - undertaken at IPN Orsay in October 2008 - on the study of a prototypical superconducting module and the feedback control systems of its cavity for the high energy part of the MYRRHA linac. First, the optimization and the design of 5-cell elliptical cavities (β=0,65), operating at 704.4 MHz, are presented. Then, the experimental work focuses on a reliability oriented study of the 'cryo-module' which hold a prototypical 5-cell cavity (β=0,47). In this study, the dynamic behavior of the fast tuning system of the cavity was measured and qualified. The 'field flatness' issue in 'low beta' multi-cell cavity was also brought to light. Finally, a fault-tolerance analysis of the linac was carried out. Toward this goal, a model of the cavity, its RF feedback loop system and its tuning system feedback loop was developed. This study enabled to determine the RF power needs, the tuning system requirements and as well as to demonstrate the feasibility of fast fault-recovery scenarios to minimize the number of beam interruptions in the MYRRHA linac. (author)

  4. A simple electron-beam lithography system

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Madsen, Dorte Nørgaard; Bøggild, Peter

    2005-01-01

    A large number of applications of electron-beam lithography (EBL) systems in nanotechnology have been demonstrated in recent years. In this paper we present a simple and general-purpose EBL system constructed by insertion of an electrostatic deflector plate system at the electron-beam exit of the...... be used to write three-dimensional nanostructures by electron-beam deposition. (C) 2004 Elsevier B.V. All rights reserved....

  5. BEAM CONTAINMENT SYSTEM FOR NSLS-II

    International Nuclear Information System (INIS)

    The shielding design for the NSLS-II will provide adequate protection for the full injected beam loss in two periods of the ring around the injection point, but the remainder of the ring is shielded for lower losses of (le) 10% full beam. This will require a system to insure that beam losses don't exceed these levels for a period of time that could cause excessive radiation levels outside the shield walls. This beam containment system will measure, provide a level of control and alarm indication of the beam power losses along the beam path from the source (e-gun, linac) thru the injection system and the storage ring. This system will consist of collimators that will provide limits to (and potentially to measure) the beam miss-steering and control the loss points of the charge and monitors that will measure the average beam current losses along the beam path and alarm when this beam power loss exceeds the level set by the shielding specifications. This will require some new ideas in beam loss detection capability and collimation. The initial planning and R and D program will be presented.

  6. The upgraded rf system for the AGS and high intensity proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, J.M. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.

    1995-05-01

    The AGS has been upgraded over the past three years to produce a record beam intensity of 6 {times} 10{sup 13} protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system`s performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading.

  7. Linear quantum feedback networks

    Science.gov (United States)

    Gough, J. E.; Gohm, R.; Yanagisawa, M.

    2008-12-01

    The mathematical theory of quantum feedback networks has recently been developed [J. Gough and M. R. James, e-print arXiv:0804.3442v2] for general open quantum dynamical systems interacting with bosonic input fields. In this article we show, for the special case of linear dynamical Markovian systems with instantaneous feedback connections, that the transfer functions can be deduced and agree with the algebraic rules obtained in the nonlinear case. Using these rules, we derive the transfer functions for linear quantum systems in series, in cascade, and in feedback arrangements mediated by beam splitter devices.

  8. Development of bunch by bunch transverse feedback system at Hefei light source

    International Nuclear Information System (INIS)

    This paper has introduced the development of the transverse bunch-by-bunch measurement and feedback system, including the experiment of damping the coupled bunch instability. Some key technologies on the system have been introduced: the vector calculation module as a signal processing module used to adjust the phase of the feedback signals, the feedback kicker cavity and the notch filter used to filter the DC component and revolution frequencies component in a signal and save the feedback power. The result of the feedback experiment is mentioned: the instability oscillation was damped when the feedback system was on. (authors)

  9. Feedback compensation network design for KAPP reactor regulating system

    International Nuclear Information System (INIS)

    The reactor power regulating system based on coolant differential temperature across the boiler is inaccurate and sluggish because of the transport delays and time constants associated with temperature measurement. Moreover the control system cannot correct promptly the disturbances transmitted by the secondary system. Above problems can be easily overcome by the reactor control system based on neutron flux measured by the out of core ionisation chambers. The report describes the design and analysis of feedback compensation network based on neutron flux measurement. Closed loop system stability analysis of Kakrapar Atomic Power Plant has been made based on linearised transfer function models of sub-system, to achieve good gain and phase control margins. The control system responses have been tested using reactor functional simulator. The design has been verified by sampled data system analysis using Z transform of the reactor mathematical model. (author). 21 refs., 1 tab

  10. The upgraded rf system for the AGS and high intensity proton beams

    International Nuclear Information System (INIS)

    The AGS has been upgraded over the past three years to produce a record beam intensity of 6 x 1013 protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system's performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading

  11. Enhancing the Impact of Formative Feedback on Student Learning through an Online Feedback System

    Science.gov (United States)

    Hatziapostolou, Thanos; Paraskakis, Iraklis

    2010-01-01

    Formative feedback is instrumental in the learning experience of a student. It can be effective in promoting learning if it is timely, personal, manageable, motivational, and in direct relation with assessment criteria. Despite its importance, however, research suggests that students are discouraged from engaging in the feedback process primarily…

  12. A new hyperchaotic system and its linear feedback control

    Institute of Scientific and Technical Information of China (English)

    Cai Guo-Liang; Zheng-Song; TianLi-Xin

    2008-01-01

    This paper reports a new hyperchaotic system by adding an additional state variable into a three-dimensional chaotic dynamical system,studies some of its basic dynamical properties,such as the hyperchaotic attractor,Lyapunov exponents,bifurcation diagram and the hyperchaotic attractor evolving into periodic,quasi-periodic dynamical behaviours by varying parameter k.Furthermore,effective linear feedback control method is used to suppress hyperchaes to unstable equilibrium,periodic orbits and quasi-periodic orbits.Numerical simulations are presented to show these results.

  13. Increase of coherence in excitable systems by delayed feedback

    Energy Technology Data Exchange (ETDEWEB)

    Prager, Tobias [Institute of Physics, Humboldt-University at Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Lerch, Hans-Philipp [Institute of Physics, Humboldt-University at Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Schimansky-Geier, Lutz [Institute of Physics, Humboldt-University at Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Schoell, Eckehard [Institut fuer Theoretische Physik, Technische Universitaet Berlin, Hardenbergstr. 36, D-10623 Berlin (Germany)

    2007-09-07

    The control of coherence and spectral properties of noise-induced oscillations by time-delayed feedback is studied in a FitzHugh-Nagumo system which serves as a paradigmatic model of excitable systems. A semianalytical approach based on a discrete model with waiting time densities is developed, which allows one to predict quantitatively the increase of coherence measured by the correlation time, and the modulation of the main frequencies of the stochastic dynamics in dependence on the delay time. The analytical mean-field approximation is in good agreement with numerical results for the full nonlinear model.

  14. The Japanese system of learning from events and related feedback

    International Nuclear Information System (INIS)

    The average annual reactor scram rate of Japan's 47 LWRs in 1994 was 0.06 times per reactor-year, and the average annual incidents and failures (hereafter called 'events') occurrence rate was 0.4 cases per reactor-year. One of the most important factors contributing to such an excellent operating performance is the perfect feedback of lessons learned from each of the events, circulated to all plants as Ministry of International Trade and Industry (MITI) administrative guidance. Another important contributing factor is intensive preventive maintenance. This feedback process has become more effective because it is followed by a second process which is carried out by utilities. The second process includes modifications of equipment to prevent any potential failure which can be foreseen from past events in domestic or foreign plants. In order to evaluate the effects of these processes on the mitigation of ageing. Japanese events which include degradation of components were selected, and the relationship between their occurrence date and the elapsed years since the first commercial operation of the relevant plant was analysed. The result of this analysis showed no notable symptoms of plant ageing even when more than 20 years had elapsed. This indicates that the Japanese system of learning from events and the related feedback also works as a side effects in preventing ageing phenomena of plants. (author). 4 figs

  15. Generation of probe signal for feedback cancellation systems

    OpenAIRE

    Odelius, Johan

    2004-01-01

    A common problem of hearing aids is whistling caused by feedback from the loudspeaker back to the microphone. A method of reducing the negative effects, caused by the feedback, is called feedback cancellation. A variant of feedback cancellation uses a probe signal, which is applied to the speaker of the hearing aid and is used to continuously estimate the feedback. Oticon A/S has suggested a master's thesis with the purpose of designing and evaluating an algorithm generating a probe signal fo...

  16. A simulation study of the global orbit feedback system for Pohang light source

    International Nuclear Information System (INIS)

    This paper describes the simulation of the global orbit feedback system using the singular value decomposition (SVD) method, the error minimization method, and the neural network method. Instead of facing unacceptable correction result raised occasionally in the SVD method, we choose the error minimization method for the global orbit feedback. This method provides minimum orbit errors while avoiding unacceptable corrections, and keeps the orbit within the dynamic aperture of the storage ring. We simulate the Pohang Light Source (PLS) storage ring using the Methodical Accelerator Design (MAD) code that generates the orbit distortions for the error minimization method and the learning data set for neural network method. In order to compare the effectiveness of the neural network method with others, a neural network is trained by the learning algorithm using the learning data set. The global response matrix with a minimum error and the trained neural network are used to the global orbit feedback system. The simulation shows that a selection of beam position monitors (BPMs) is very sensitive in the reduction of rms orbit distortions, and the random choice gives better results than any other cases. (author)

  17. Output feedback control of a mechanical system using magnetic levitation.

    Science.gov (United States)

    Beltran-Carbajal, F; Valderrabano-Gonzalez, A; Rosas-Caro, J C; Favela-Contreras, A

    2015-07-01

    This paper presents an application of a nonlinear magnetic levitation system to the problem of efficient active control of mass-spring-damper mechanical systems. An output feedback control scheme is proposed for reference position trajectory tracking tasks on the flexible mechanical system. The electromagnetically actuated system is shown to be a differentially flat nonlinear system. An extended state estimation approach is also proposed to obtain estimates of velocity, acceleration and disturbance signals. The differential flatness structural property of the system is then employed for the synthesis of the controller and the signal estimation approach presented in this work. Some experimental and simulation results are included to show the efficient performance of the control approach and the effective estimation of the unknown signals. PMID:25707718

  18. Neutral beam data systems at ORNL

    International Nuclear Information System (INIS)

    A control system for neutral injection beam lines has been designed, implemented, and used with much success. Despite the problems with very high power levels this system is very successful in relieving the operators burdens of slow conditioning, data recording, and mode switching. The use of computer control with multiple beam lines now appears very promising

  19. Feedback system of a liquid-nitrogen-cooled double-crystal monochromator: design and performances.

    Science.gov (United States)

    Proux, Olivier; Nassif, Vivian; Prat, Alain; Ulrich, Olivier; Lahera, Eric; Biquard, Xavier; Menthonnex, Jean Jacques; Hazemann, Jean Louis

    2006-01-01

    A new set-up is reported of an indirect cryogenic cooling system for a double-crystal monochromator which runs on the BM30b/FAME beamline at the ESRF (Grenoble, France). This device has been conceived to limit the vibrations on the first diffracting crystal and to maintain it at a constant temperature. These points are crucial for maximizing the beamline stability. Moreover, the relative angular position of the second crystal can be dynamically adjusted by a piezoelectric transducer coupled with a feedback system in order to always be at the maximum of the rocking curve during an X-ray absorption spectroscopy scan. The temperature is stabilized to an accuracy of 0.01 degrees , with two principal consequences. The energy resolution is close to the theoretical value [DeltaE/E = 5.6 x 10(-6) for Si(220)] and the precision of the energy positioning is extremely good even if the power load changes. A feedback mechanism allows a permanent and automatic optimization of the angle between the two crystals of the monochromator. The intensity of the monochromatic beam remains optimized (i) when the intensity of the electron beam decreases in the storage ring and (ii) during an energy scan. PMID:16371709

  20. BECOLA Beam Line Construction and Laser System

    Science.gov (United States)

    Pedicini, Eowyn; Minamisono, Kei; Barquest, Brad; Bollen, Georg; Klose, Andrew; Mantica, Paul; Morrissey, Dave; Ringle, Ryan; Schwarz, Stefan; Vinnikova, Sophia

    2010-11-01

    The BECOLA (BEam COoler and LAser spectroscopy) facility is being installed at NSCL for experiments on radioactive nuclides.ootnotetextK. Minamisono et al, Proc. Inst. Nucl. Theory 16, 180 (2009). Low energy ion beams will be cooled/bunched in an RFQ ion trap and then extracted to a max of 60 kV. The ion beam will be neutralized through a charge exchange cell (CEC), and remaining ions will be removed by a deflector and collected in a Faraday cup. Collinear laser spectroscopy will be used to measure the atomic hyperfine structure, and nuclear properties will be extracted. The assembly, vacuum testing, and optical alignment of the CEC have been completed and the ion deflector and Faraday cup were also assembled. Stabilization of the Ti:sapphire laser to be used for spectroscopy is achieved through a feedback loop using a precision wavelength meter that is calibrated by a stabilized He-Ne laser. Coupling the He-Ne laser into a single-mode optical fiber was optimized for stable operation of the feedback loop. Finally, a wall chart of nuclear moments was prepared to view trends in μ and Q for nuclear ground states for planning future measurements.

  1. Simulation studies for ion beam extraction systems

    Energy Technology Data Exchange (ETDEWEB)

    Abdelrahman, M.M.; Zakhary, S.G. [Atomic Energy, Cairo (Egypt). Nuclear Research Center. Accelerators and Ion Sources Dept.], e-mail: moustafa82003@yahoo.com

    2009-06-15

    The characteristics of the ion beam extracted from an ion sources were investigated using computer code SIMION 3 D Version 7.0. It has been used to evaluate the extraction system in order to produce an ion beam with high current and low beam emittance. The results show that the shape of the extraction electrode plays an important role in ion beam formation. Comparison has been made between two extraction systems, Pierce extraction electrode and spherical extraction electrode. The results show that the spherical extraction system yields ion extraction beam with lower emittance and radius than that the Pierce system. The simulation can provide the basis for optimizing the extraction system and the acceleration gap for ion source. (author)

  2. Laser experimental system as teaching aid for demonstrating basic phenomena of laser feedback

    International Nuclear Information System (INIS)

    An experimental laser teaching system is developed to demonstrate laser feedback phenomena, which bring great harm to optical communication and benefits to precision measurement. The system consists of an orthogonally polarized He-Ne laser, a feedback mirror which reflects the laser output light into the laser cavity, and an optical attenuator which changes the intensity of the feedback light. As the feedback mirror is driven by a piezoelectric ceramic, the attenuator is adjusted and the feedback mirror is tilted, the system can demonstrate many basic laser feedback phenomena, including weak, moderate and strong optical feedback, multiple feedback and polarization flipping. Demonstrations of these phenomena can give students a better understanding about the intensity and polarization of lasers. The system is well designed and assembled, simple to operate, and provides a valuable teaching aid at an undergraduate level. (paper)

  3. Low energy beam transport system developments

    International Nuclear Information System (INIS)

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H− beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H− beams, but such gas densities cause unacceptably high H− beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H− beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed

  4. Low energy beam transport system developments

    Science.gov (United States)

    Dudnikov, V.; Han, B.; Stockli, M.; Welton, R.; Dudnikova, G.

    2015-04-01

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H- beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H- beams, but such gas densities cause unacceptably high H- beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H- beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  5. 972-MHz RF digital feedback control system for J-PARC linac

    International Nuclear Information System (INIS)

    A 972-MHz RF system is being developed for 400-MeV upgrade of the J-PARC linac. The accelerating field stabilities should be less than +/-1% in amplitude and +/-1deg in phase. The basic digital LLRF (Low-Level RF) concept is the same as that of the present 324-MHz system with a compact-PCI crate. The main alterations are RF and clock generator (RF and CLK), mixer and I/Q modulator (IQ and Mixer) and digital LLRF algorithm. Since the typical decay time of the new system is faster (because its operational frequency is higher than that of the present 324-MHz cavity), chopped beam compensation is essential. The performance study of the digital feedback system with a cavity simulator is summarized. (author)

  6. Gamma beam system at ELI-NP

    Energy Technology Data Exchange (ETDEWEB)

    Ur, Calin Alexandru, E-mail: calin.ur@eli-np.ro [Extreme Light Infrastructure, IFIN-HH, Magurele-Bucharest (Romania)

    2015-02-24

    The Gamma Beam System of ELI-NP will produce brilliant, quasi-monochromatic gamma-ray beams via Inverse Compton Scattering of short laser pulses on relativistic electron beam pulses. The scattered radiation is Doppler upshifted by more than 1,000,000 times and is forward focused in a narrow, polarized, tunable, laser-like beam. The gamma-ray beam at ELI-NP will be characterized by large spectral density of about 10{sup 4} photons/s/eV, narrow bandwidth (< 0.5%) and tunable energy from 200 keV up to about 20 MeV. The Gamma Beam System is a state-of-the-art equipment employing techniques and technologies at the limits of the present-day's knowledge.

  7. Progress of beam diagnosis system for EAST neutral beam injector

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Y. J., E-mail: yjxu@ipp.ac.cn; Hu, C. D.; Yu, L.; Liang, L. Z.; Zhang, W. T.; Chen, Y.; Li, X. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China)

    2016-02-15

    Neutral beam injection has been recognized as one of the most effective means for plasma heating. According to the research plan of the EAST physics experiment, two sets of neutral beam injector (NBI) were built and operational in 2014. The paper presents the development of beam diagnosis system for EAST NBI and the latest experiment results obtained on the test-stand and EAST-NBI-1 and 2. The results show that the optimal divergence angle is (0.62°, 1.57°) and the full energy particle is up to 77%. They indicate that EAST NBI work properly and all targets reach or almost reach the design targets. All these lay a solid foundation for the achievement of high quality plasma heating for EAST.

  8. Experimental spatial rogue patterns in an optical feedback system

    Directory of Open Access Journals (Sweden)

    V. Odent

    2010-12-01

    Full Text Available We study pattern formation in an optical system composed of a Kerr medium subjected to optical feedback but in a regime very far from the modulational instability threshold. In this highly nonlinear regime, the dynamics is turbulent and the associated one-dimensional patterns depict rare and intense localized optical peaks. We analyse numerically and experimentally the statistics and features of these intense optical peaks and show that their probability density functions (PDF have a long tail indicating the occurrence of rogue events.

  9. Dynamic boundary controls of a rotating body-beam system with time-varying angular velocity

    OpenAIRE

    Boumediène Chentouf

    2004-01-01

    This paper deals with feedback stabilization of a flexible beam clamped at a rigid body and free at the other end. We assume that there is no damping and the rigid body rotates with a nonconstant angular velocity. To stabilize this system, we propose a feedback law which consists of a control torque applied on the rigid body and either a dynamic boundary control moment or a dynamic boundary control force or both of them applied at the free end of the beam. Then it is ...

  10. Advanced Light Source beam diagnostics systems

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS), a third-generation synchrotron light source, has been recently commissioned. Beam diagnostics were very important to the success of the operation. Each diagnostic system is described in this paper along with detailed discussion of its performance. Some of the systems have been in operation for two years. Others, in the storage ring, have not yet been fully commissioned. These systems were, however, working well enough to provide the essential information needed to store beam. The devices described in this paper include wall current monitors, a beam charge monitor, a 50 ohm Faraday cup, DC current transformers, broad-hand striplines, fluorescence screens, beam collimators and scrapers, and beam position monitors. Also, the means by which waveforms are digitized and displayed in the control room is discussed

  11. Vibrations and stability of complex beam systems

    CERN Document Server

    Stojanović, Vladimir

    2015-01-01

     This book reports on solved problems concerning vibrations and stability of complex beam systems. The complexity of a system is considered from two points of view: the complexity originating from the nature of the structure, in the case of two or more elastically connected beams; and the complexity derived from the dynamic behavior of the system, in the case of a damaged single beam, resulting from the harm done to its simple structure. Furthermore, the book describes the analytical derivation of equations of two or more elastically connected beams, using four different theories (Euler, Rayleigh, Timoshenko and Reddy-Bickford). It also reports on a new, improved p-version of the finite element method for geometrically nonlinear vibrations. The new method provides more accurate approximations of solutions, while also allowing us to analyze geometrically nonlinear vibrations. The book describes the appearance of longitudinal vibrations of damaged clamped-clamped beams as a result of discontinuity (damage). It...

  12. Robust adaptive output feedback control of nonlinearly parameterized systems

    Institute of Scientific and Technical Information of China (English)

    LIU Yusheng; LI Xingyuan

    2007-01-01

    The ideas of adaptive nonlinear damping and changing supply functions were used to counteract the effects of parameter and nonlinear uncertainties,unmodeled dynamics and unknown bounded disturbances.The high-gain observer was used to estimate the state of the system.A robust adaptive output feedback control scheme was proposed for nonlinearly parameterized systems represented by inputoutput models.The scheme does not need to estimate the unknown parameters nor add a dynamical signal to dominate the effects of unmodeled dynamics.It is proven that the proposed control scheme guarantees that all the variables in the closed-loop system are bounded and the mean-square tracking error can be made arbitrarily small by choosing some design parameters appropriately.Simulation results have illustrated the effectiveness of the proposed robust adaptive control scheme.

  13. Output feedback trajectory stabilization of the uncertainty DC servomechanism system.

    Science.gov (United States)

    Aguilar-Ibañez, Carlos; Garrido-Moctezuma, Ruben; Davila, Jorge

    2012-11-01

    This work proposes a solution for the output feedback trajectory-tracking problem in the case of an uncertain DC servomechanism system. The system consists of a pendulum actuated by a DC motor and subject to a time-varying bounded disturbance. The control law consists of a Proportional Derivative controller and an uncertain estimator that allows compensating the effects of the unknown bounded perturbation. Because the motor velocity state is not available from measurements, a second-order sliding-mode observer permits the estimation of this variable in finite time. This last feature allows applying the Separation Principle. The convergence analysis is carried out by means of the Lyapunov method. Results obtained from numerical simulations and experiments in a laboratory prototype show the performance of the closed loop system. PMID:22884179

  14. Controlling extended systems with spatially filtered, time-delayed feedback

    CERN Document Server

    Bleich, M E; Moloney, J V; Socolar, J E S; Bleich, Michael E.; Hochheiser, David; Moloney, Jerome V.; Socolar, Joshua E. S.

    1997-01-01

    We investigate a control technique for spatially extended systems combining spatial filtering with a previously studied form of time-delay feedback. The scheme is naturally suited to real-time control of optical systems. We apply the control scheme to a model of a transversely extended semiconductor laser in which a desirable, coherent traveling wave state exists, but is a member of a nowhere stable family. Our scheme stabilizes this state, and directs the system towards it from realistic, distant and noisy initial conditions. As confirmed by numerical simulation, a linear stability analysis about the controlled state accurately predicts when the scheme is successful, and illustrates some key features of the control including the individual merit of, and interplay between, the spatial and temporal degrees of freedom in the control.

  15. A method for designing robust multivariable feedback systems

    Science.gov (United States)

    Milich, David Albert; Athans, Michael; Valavani, Lena; Stein, Gunter

    1988-01-01

    A new methodology is developed for the synthesis of linear, time-invariant (LTI) controllers for multivariable LTI systems. The aim is to achieve stability and performance robustness of the feedback system in the presence of multiple unstructured uncertainty blocks; i.e., to satisfy a frequency-domain inequality in terms of the structured singular value. The design technique is referred to as the Causality Recovery Methodology (CRM). Starting with an initial (nominally) stabilizing compensator, the CRM produces a closed-loop system whose performance-robustness is at least as good as, and hopefully superior to, that of the original design. The robustness improvement is obtained by solving an infinite-dimensional, convex optimization program. A finite-dimensional implementation of the CRM was developed, and it was applied to a multivariate design example.

  16. A Measurement Feedback System (MFS) Is Necessary to Improve Mental Health Outcomes

    Science.gov (United States)

    Bickman, Leonard

    2008-01-01

    The importance of measurement feedback system (MFS) for the improvement of mental health services for youths is discussed. As feedback obtained from clients and families is subject to distortions, a standardized MFS including clinical processes, contexts, outcomes, and feedback to clinicians and supervisors is necessary for improvement in quality…

  17. Feedback passivity of nonlinear discrete-time systems with direct input-output link

    OpenAIRE

    Navarro López, Eva María; Fossas Colet, Enric

    2004-01-01

    This paper is devoted to the study of the feedback passivity property in nonlinear discrete-time systems. The relative degree and zero dynamics of the non-passive system are related to the feedback passivity of the system. Two main results are presented. First, some relative degreerelated properties of passive systems in general form are stated. Second, sufficient conditions in order to render a multiple-input multiple-output (MIMO) system passive by means of a static state feedback control l...

  18. Dynamics and control of a financial system with time-delayed feedbacks

    International Nuclear Information System (INIS)

    Complex behaviors in a financial system with time-delayed feedbacks are discussed in this study via numerical modeling. The system shows complex dynamics such as periodic, quasi-periodic, and chaotic behaviors. Both period doubling and inverse period doubling routes were found in this system. This paper also shows that the attractor merging crisis is a fundamental feature of nonlinear financial systems with time-delayed feedbacks. Control of the deterministic chaos in the financial system can be realized using Pyragas feedbacks

  19. TUNE FEEDBACK AT RHIC

    International Nuclear Information System (INIS)

    Preliminary phase-locked loop betatron tune measurement results were obtained during RHIC 2000 with a resonant Beam Position Monitor. These results suggested the possibility of incorporating PLL tune measurement into a tune feedback system for RHIC 2001. Tune feedback is useful in a superconducting accelerator, where the machine cycle time is long and inefficient acceleration due to resonance crossing is not comfortably tolerated. This is particularly true with the higher beam intensities planned for RHIC 2001. We present descriptions of a PLL tune measurement system implemented in the DSP/FPGA environment of a RHIC BPM electronics module and the feedback system into which the measurement is incorporated to regulate tune. In addition, we present results from the commissioning of this system during RHIC 2001

  20. Interference-aware random beam selection for spectrum sharing systems

    KAUST Repository

    Abdallah, Mohamed M.

    2012-09-01

    Spectrum sharing systems have been introduced to alleviate the problem of spectrum scarcity by allowing secondary unlicensed networks to share the spectrum with primary licensed networks under acceptable interference levels to the primary users. In this paper, we develop interference-aware random beam selection schemes that provide enhanced throughput for the secondary link under the condition that the interference observed at the primary link is within a predetermined acceptable value. For a secondary transmitter equipped with multiple antennas, our schemes select a random beam, among a set of power- optimized orthogonal random beams, that maximizes the capacity of the secondary link while satisfying the interference constraint at the primary receiver for different levels of feedback information describing the interference level at the primary receiver. For the proposed schemes, we develop a statistical analysis for the signal-to-noise and interference ratio (SINR) statistics as well as the capacity of the secondary link. Finally, we present numerical results that study the effect of system parameters including number of beams and the maximum transmission power on the capacity of the secondary link attained using the proposed schemes. © 2012 IEEE.

  1. Quantifying and Reducing Climate-Carbon Cycle Feedback Uncertainties: Analysis of CMIP5 Earth System Model Feedbacks

    Science.gov (United States)

    Hoffman, F. M.; Randerson, J. T.

    2011-12-01

    Increasing atmospheric carbon dioxide (CO2) concentrations, resulting from anthropogenic perturbation of the global carbon cycle, are altering the Earth's climate. Climate change is expected to induce feedbacks on future CO2 concentrations and on the climate system itself. These feedbacks are highly uncertain, potentially large, and difficult to predict using Earth System Models (ESMs). In order to reduce the range of uncertainty in climate predictions, model representation of feedbacks must be improved through comparisons with contemporary observations. In this study, we quantify the terrestrial and ocean carbon storage sensitivity to climate and atmospheric CO2 concentration of ESMs participating in the Climate Model Intercomparison Project Phase 5 (CMIP5) following the methodology of Friedlingstein et al. (2006). In order to evaluate the models' abilities to capture the 21st century carbon cycle and to offer possible constraints on the modeled feedback strengths, comparisons with contemporary observations will be made over three different time scales: seasonal to annual, interannual to decadal, and decadal to centennial. A conceptual framework for evaluating climate-carbon cycle feedbacks in global models--employing best-available observational data--will be presented, along with results from application of this framework to CMIP5 model output. Included in the analysis will be prototype model evaluation benchmarks of the carbon cycle being designed for the International Land Model Benchmarking (ILAMB) Project.

  2. Acoustic Beam Forming Array Using Feedback-Controlled Microphones for Tuning and Self-Matching of Frequency Response

    Science.gov (United States)

    Radcliffe, Eliott (Inventor); Naguib, Ahmed (Inventor); Humphreys, Jr., William M. (Inventor)

    2014-01-01

    A feedback-controlled microphone includes a microphone body and a membrane operatively connected to the body. The membrane is configured to be initially deflected by acoustic pressure such that the initial deflection is characterized by a frequency response. The microphone also includes a sensor configured to detect the frequency response of the initial deflection and generate an output voltage indicative thereof. The microphone additionally includes a compensator in electric communication with the sensor and configured to establish a regulated voltage in response to the output voltage. Furthermore, the microphone includes an actuator in electric communication with the compensator, wherein the actuator is configured to secondarily deflect the membrane in opposition to the initial deflection such that the frequency response is adjusted. An acoustic beam forming microphone array including a plurality of the above feedback-controlled microphones is also disclosed.

  3. Accelerating of Image Retrieval in CBIR System with Relevance Feedback

    Directory of Open Access Journals (Sweden)

    Branimir Reljin

    2007-01-01

    Full Text Available Content-based image retrieval (CBIR system with relevance feedback, which uses the algorithm for feature-vector (FV dimension reduction, is described. Feature-vector reduction (FVR exploits the clustering of FV components for a given query. Clustering is based on the comparison of magnitudes of FV components of a query. Instead of all FV components describing color, line directions, and texture, only their representative members describing FV clusters are used for retrieval. In this way, the “curse of dimensionality” is bypassed since redundant components of a query FV are rejected. It was shown that about one tenth of total FV components (i.e., the reduction of 90% is sufficient for retrieval, without significant degradation of accuracy. Consequently, the retrieving process is accelerated. Moreover, even better balancing between color and line/texture features is obtained. The efficiency of FVR CBIR system was tested over TRECVid 2006 and Corel 60 K datasets.

  4. Detection systems for radioactive ion beams

    International Nuclear Information System (INIS)

    Two main methods are used to produce radioactive ion beams: -) the ISOL method (isotope separation on-line) in which the stable beam interacts with a thick target, the reaction products diffuse outside the target and are transferred to a source where they are ionized, a mass separator and a post-accelerator drive the selected radioactive ions to the right energy; -) the in-flight fragmentation method in which the stable beam interacts with a thin target, the reaction products are emitted from the target with a restricted angular distribution and a velocity close to that of the incident beam, the experimenter has to take advantage from the reaction kinetics to get the right particle beam. Characteristic time is far longer with the ISOL method but the beam intensity is much better because of the use of a post-accelerator. In both cases, the beam intensity is lower by several orders of magnitude than in the case of a stable beam. This article presents all the constraints imposed by radioactive beams to the detection systems of the reaction products and gives new technical solutions according to the type of nuclear reaction studied. (A.C.)

  5. Integration of a force feedback joystick with a VR system

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A.C. [ENEA, Centro Ricerche Casaccia, S. Maria di Galeria, RM (Italy). Dipt. Innovazione

    1999-07-01

    The report shows the result carried out at the Robotics and Information Systems Division of ENEA (National Agency for New Technology, Energy and the Environment) in the Casaccia Centre (Rome). The study presents an approach to the problem of integrating force feedback with a complete real-time virtual environment system: in particular bulky computations for graphics or simulation require a decoupling of the haptic servo loop from the main application loop if high-quality forces are to be obtained. The control system has been developed for the force-feedback joystick Impulse 2000, from Immersion Co., and the integration of it to a virtual environment is presented here. Technical issues related to the development of control architectures for Internet-based exchange of haptic information, in a stable way are discussed. [Italian] Il presente rapporto descrive il lavoro eseguito nella divisione robotica e informatica del dipartimento innovazione dell'ENEA del centro ricerche della Casaccia (Roma): il sistema di controllo del dispositivo con ritorno di forza in un sistema RV (real-time virtual environment system) ed illustra l'approccio a questa problematica ed in particolare la lentezza di esecuzione del ciclo di calcoli per la resa delle immagini da parte del sistema grafico e del ciclio per la simulazione della dinamica di sistema. Viene descritto il sistema di controllo per il joystick con ritorno di forza Impulse 2000 (Immersion Co.) e la sua integrazione ad un ambiente virtuale. Sono inoltre discusse le problematiche connesse allo sviluppo di sistemi che consentano lo scambio dell'informazione tattile attraverso Internet.

  6. Walking beam pumping unit system efficiency measurements

    International Nuclear Information System (INIS)

    The cost of electricity used by walking beam pumping units is a major expense in producing crude oil. However, only very limited information is available on the efficiency of beam pumping systems and less is known about the efficiency of the various components of the pumping units. This paper presents and discusses measurements that have been made on wells at several Shell locations and on a specially designed walking beam pump test stand at Lufkin Industries. These measurements were made in order to determine the overall system efficiency and efficiency of individual components. The results of this work show that the overall beam pumping system efficiency is normally between 48 and 58 percent. This is primarily dependent on the motor size, motor type, gearbox size, system's age, production, pump size, tubing size, and rod sizes

  7. Stabilization of the Gas Flow in Networks: Boundary Feedback Stabilization of Quasilinear Hyperbolic Systems on Networks

    OpenAIRE

    Dick, Markus

    2012-01-01

    We study the stabilization of quasilinear hyperbolic PDE systems on networks. To do so we develop stabilizing boundary feedback controls. We study feedback controls without and with time-varying delays. To analyze the system evolution we introduce strict Lyapunov functions which are weighted and squared L2- and H1-norms of the solutions of the quasilinear systems. The exponential weights in the Lyapunov functions contain the system eigenvalues. The feedback controls with time delay are repres...

  8. Construction of experience feedback system for equipment supervision in nuclear engineering

    International Nuclear Information System (INIS)

    Based on the analysis of the experience sources on equipment supervision in nuclear engineering, the details of the organization principle, working flow, and report requirement for the experience feedback system are introduced. The function range and its roll in the experience feedback system of the nuclear authority, nuclear power plant owners and equipment supervision organizations are illustrated. The standardization working requirements in the information gathering, analyzing, feedback and tracking process, and the characteristics and form of the incident report and feedback report are proposed. It emphasizes that the method for combined analysis of one significant incident and the whole incidents shall be adopted in the information analysis, and the experience feedback shall be considered in the development of equipment supervision technique and the equipment manufacturing, thus to maximize the use of experience feedback information to improve the pertinency and effectiveness of the experience feedback system. (authors)

  9. Fast beam mode switching system at KEK E-/E+ linac

    International Nuclear Information System (INIS)

    KEK 8-GeV Linac provides electrons and positrons to Photon Factory (PF) and B-Factory (KEKB). Because of the nature of those factory machines, both quantity and quality of the beams are required. In order to improve the injections, quasi top-up injections of electrons to PF and KEKB rings have been planned and a new beam transport line was built. Fast beam switching mechanisms are being developed and installed. Among those mechanisms the fast switching of linac parameters of timing signals, low-level rf devices, beam instrumentation and beam feedback systems need to be developed. In order to realize them the event distribution system is installed, and other sub-systems will follow the event notification. The rf synchronization scheme is also upgraded. The system is under testing part by part, and will be used in 2007. (author)

  10. Low energy beam transport system developments

    Energy Technology Data Exchange (ETDEWEB)

    Dudnikov, V., E-mail: vadim@muonsinc.com [Muons, Inc., Batavia, IL 60510 (United States); Han, B.; Stockli, M.; Welton, R. [ORNL, Oak Ridge, TN 37831 (United States); Dudnikova, G. [University of Maryland, College Park, MD 3261 (United States); Institute of Computational Technologies SBRAS, Novosibirsk (Russian Federation)

    2015-04-08

    For high brightness beam production it is important to preserve the brightness in the low energy beam transport system (LEBT) used to transport and match the ion beams to the next stage of acceleration, usually an RFQ. While electrostatic focusing can be problematic for high current beam transport, reliable electrostatic LEBT operation has been demonstrated with H{sup −} beams up to 60 mA. Now, however, it is commonly accepted that an optimal LEBT for high current accelerator applications consists of focusing solenoids with space charge compensation. Two-solenoid LEBTs are successfully used for high current (>100 mA) proton beam transport. Preservation of low emittances (~0.15 π mm-mrad) requires the addition of a heavy gas (Xe, Kr), which causes ~5% of proton loss in a 1 m long LEBT. Similar Xe densities would be required to preserve low emittances of H{sup −} beams, but such gas densities cause unacceptably high H{sup −} beam losses. A short LEBT with only one short solenoid, movable for RFQ matching, can be used for reduced negative ion stripping. A strong electrostatic-focusing LEBT has been successfully adopted for transport of high current H{sup −} beams in the SNS Front End. Some modifications of such electrostatic LEBTs are expected to improve the reliable transport of intense positive and negative ion beams without greatly degrading their low emittances. We concentrate on processes that determine the beam brightness degradation and on their prevention. Proposed improvements to the SNS electrostatic LEBT are discussed.

  11. Beam position monitoring electronics system for LEHIPA

    International Nuclear Information System (INIS)

    The primary function of beam position monitoring system (BPM) is to determine the position of the beam with respect to the centre of beam pipe. The present system is VME based and mainly consists of two VME boards one Analog and one Digital. The system has been developed for 352.21 MHz Low Energy High Intensity Proton Accelerator (LEHIPA). The electronic system processes the signals coming from the sensor which incorporates four button pick-ups placed orthogonally around the beam pipe. The fundamental component of the beam signal is extracted from the signals from the sensor and amplified with gain stabilized amplifiers on the analog board. Offset tone based technique has been used for the stabilization of the gain of the amplifiers against changes in temperature, power supply, etc. The filtered and amplified signals are given to the digital board for digitization and further processing. The signal processing consists of demodulation in I-Q domain followed by CORDIC which gives the signal information in the form of amplitude and phase. The stabilization of the gain is also carried out in the digital domain. The phase information can be utilized for energy gain measurements. The amplitudes give the position of the beam which is calculated online in FPGA using difference over sum method. The EPICS system has been chosen as the basic framework for command control. The hardware architecture is as per standard VME crate. (author)

  12. Noise-induced resonance in delayed feedback systems

    OpenAIRE

    Masoller Alonso, Cristina

    2002-01-01

    We study the influence of noise in the dynamics of a laser with optical feedback. For appropriate choices of the feedback parameters, several attractors coexist, and large enough noise induces jumps among the attractors. Based on the residence times probability density, it is shown that with increasing noise the dynamics of attractor jumping exhibits a resonant behavior, which is due to the interplay of noise and delayed feedback. It is also shown that this type of resonance is not specific t...

  13. Using Time-Delay Feedback for Control and Synchronization of Dynamical Systems

    Science.gov (United States)

    Pyragas, Kestutis; Pyragas, Viktoras; Pyragiene, Tatjana

    2013-01-01

    An application of time-delayed feedback signals in the field of chaos control and synchronization is discussed. In the first part of the chapter, we present an overview of delayed feedback control techniques for stabilization of unstable periodic orbits of chaotic systems. The second part is devoted to anticipating synchronization, where the time-delayed feedback in a slave system enables us to forecast the chaotic dynamics of the identical master system.

  14. A simple electron-beam lithography system

    DEFF Research Database (Denmark)

    Mølhave, Kristian; Madsen, Dorte Nørgaard; Bøggild, Peter

    2005-01-01

    A large number of applications of electron-beam lithography (EBL) systems in nanotechnology have been demonstrated in recent years. In this paper we present a simple and general-purpose EBL system constructed by insertion of an electrostatic deflector plate system at the electron-beam exit of the...... column of a scanning electron microscope (SEM). The system can easily be mounted on most standard SEM systems. The tested setup allows an area of up to about 50 x 50 pm to be scanned, if the upper limit for acceptable reduction of the SEM resolution is set to 10 run. We demonstrate how the EBL system can...... be used to write three-dimensional nanostructures by electron-beam deposition. (C) 2004 Elsevier B.V. All rights reserved....

  15. Antares beam-alignment-system performance

    International Nuclear Information System (INIS)

    The beam alignment system for the 24-beam-sector Antares CO2 fusion laser automatically aligns more than 200 optical elements. A visible-wavelength alignment technique is employed which uses a telescope/TV system to view point-light sources appropriately located down the beamline. The centroids of the light spots are determined by a video tracker, which generates error signals used by the computer control system to move appropriate mirrors in a closed-loop system. Final touch-up alignment is accomplished by projecting a CO2 alignment laser beam through the system and sensing its position at the target location. The techniques and control algorithms employed have resulted in alignment accuracies exceeding design requirements. By employing video processing to determine the centroids of diffraction images and by averaging over multiple TV frames, we achieve alignment accuracies better than 0.1 times system diffraction limits in the presence of air turbulence

  16. Model predictive control for slow orbit feedback control system of Indus-2

    International Nuclear Information System (INIS)

    Indus-2 is India's 3rd generation 2.5 GeV synchrotron radiation source. Experiments performed at synchrotron radiation beamlines are very sensitive to synchrotron radiation source point position, thus any position change (slow occurring or fast occurring) is required to be corrected for stable synchrotron radiation in Indus-2. The slow occurring electron beam position variations are controlled in Indus-2 by slow orbit feedback (SOFB) control system. The present SOFB system of Indus-2 uses PID controller to confine the beam position variation within limits. Considering the transport delay, the advanced machines are trying model oriented controllers like internal model controller towards better controller design. Considering the possibility of getting better stability and optimized operation for SOFB control system when machine is made to move from one operating point to another operating point, a new model based predictive control scheme is in the implementation stage at Indus- 2. This paper discusses the new model predictive controller (MPC) for SOFB along with some of the simulation results obtained by applying this scheme over the Indus-2 system model. (author)

  17. Iterative Feedback Tuning in district heating systems; Iterative Feedback Tuning i vaermeproduktionsanlaeggningar

    Energy Technology Data Exchange (ETDEWEB)

    Raaberg, Martin; Velut, Stephane; Bari, Siavosh Amanat

    2010-10-15

    The project goal is to evaluate and describe how Iterative Feedback Tuning (IFT) can be used to tune controllers in the typical control loops in heat- and power plants. There are only a few practical studies carried out for IFT and they are not really relevant for power and heat processes. It is the practical problems in implementing the IFT and the result of trimming that is the focus of this project. The project will start with theoretical studies of the IFT-method, then realization and simple simulations in scilab. The IFT equations are then implemented in Freelance 2000, an ABB control system, for practical tests on a SISO- and a MIMO-process. By performing reproducible experiments on the process and analyze the results IFT can adjust the controller parameters to minimize a cost function that represents the control goal. The project selected for SISO experiments a pressure controller in an oil transportation system. By controlling the valve position of a control valve for the reversal to the supply tank, the pressure in the oil transport system is regulated. A disturbance in oil pressure can be achieved by changing the position of a valve that lets oil through to the day tank. The selected MIMO-process is a pre-heater in a degassing process. In this process, a valve on the secondary side is utilized to control the flow in the secondary system. A valve on the primary side is utilized to control the district heating water flow through the heat exchanger to control the temperature on the secondary side. An increased secondary flow increases the heat demand and thus requiring an increase in primary flow to maintain the secondary side outlet temperature. This is the cross-coupling responsible for why it is an advantage to consider the process as multi-variable. Using the IFT method, the two original PID-controllers and a feed-forward controller is tuned simultaneously. IFT-method was difficult to implement but worked well in both simulations and in real processes

  18. User Driven Feedback Control System driven using CAN Protocol

    Directory of Open Access Journals (Sweden)

    Ankita Goyal

    2013-09-01

    Full Text Available -Industrial automation is a sector having vast possibilities for major improvements. The system described in this paper consists of a console master computer (CMC which will monitor various physical nodes usually found in a large industry. The proposed work analyzes the capability of CAN networking which includes data traffic management. The CMC is designed using MATLAB 7.12; the CAN networking is supported using the Vehicular Network Toolbox. The proposed system using CAN has the advantages of being simple in its design which contributes to the overall low cost. The novelty of the work lies in the low cost approach, and fails safe methodology of CAN communication. The proposed system is capable of sending and receiving signals with the additional benefit of feedback mechanism .The proposed work is implementable in any industry with the cost advantage of CAN interface. The proposed work can be used as a cheaper and robust alternative to native technologies like PLC (Programmable Logic Controller. Moreover, the CAN network system is immune from the electrical interferences.

  19. Investigation of transient processes at the DELTA electron storage ring using a digital bunch-by-bunch feedback system

    International Nuclear Information System (INIS)

    At the 1.5-GeV synchrotron radiation source DELTA, operated by the TU Dortmund University, intensive synchrotron radiation in the spectral range from hard X-rays to THz radiation is generated by the circular deflection of highly relativistic electron bunches. Interacting with the vacuum chamber wall, the electron bunches create electric fields, which can act back on subsequent bunches. With increasing beam current, the excitation is enhanced so that the electron beam is unstable, which means that the electron bunches oscillate longitudinally or transversely relative to their reference position. The oscillations reduce the quality of the synchrotron radiation and limit the maximum storable beam current. Within the scope of this thesis, the beam instabilities at the storage ring were systematically investigated. A digital bunch-by-bunch feedback system was installed and commissioned, which allows to detect and digitize the position of each electron bunch at each turn. Based on the input signal, a correction signal is calculated in order to suppress transverse and longitudinal oscillation of the bunches. In addition, it is possible to excite dedicated bunches. The systematic excitation of all coupled-bunch modes allowed for the first time to determine the damping rates of all 192 eigenmodes of the electron beam. The current dependence of the damping rates was investigated and an instability threshold was found. Besides the investigation of multibunch instabilities, single-bunch instabilities are discussed. In addition, the acquisition unit of the digital feedback system can be triggered on external events. This was used to investigate the injection process and beam losses. It was shown that the transverse feedback system increases the injection efficiency. Another aspect of this thesis is the improvement of the signal quality of ultrashort coherent synchrotron radiation pulses, which are generated by the short-pulse facility at DELTA. The short-pulse facility is based

  20. Investigation of transient processes at the DELTA electron storage ring using a digital bunch-by-bunch feedback system

    Energy Technology Data Exchange (ETDEWEB)

    Hoener, Markus

    2015-07-01

    At the 1.5-GeV synchrotron radiation source DELTA, operated by the TU Dortmund University, intensive synchrotron radiation in the spectral range from hard X-rays to THz radiation is generated by the circular deflection of highly relativistic electron bunches. Interacting with the vacuum chamber wall, the electron bunches create electric fields, which can act back on subsequent bunches. With increasing beam current, the excitation is enhanced so that the electron beam is unstable, which means that the electron bunches oscillate longitudinally or transversely relative to their reference position. The oscillations reduce the quality of the synchrotron radiation and limit the maximum storable beam current. Within the scope of this thesis, the beam instabilities at the storage ring were systematically investigated. A digital bunch-by-bunch feedback system was installed and commissioned, which allows to detect and digitize the position of each electron bunch at each turn. Based on the input signal, a correction signal is calculated in order to suppress transverse and longitudinal oscillation of the bunches. In addition, it is possible to excite dedicated bunches. The systematic excitation of all coupled-bunch modes allowed for the first time to determine the damping rates of all 192 eigenmodes of the electron beam. The current dependence of the damping rates was investigated and an instability threshold was found. Besides the investigation of multibunch instabilities, single-bunch instabilities are discussed. In addition, the acquisition unit of the digital feedback system can be triggered on external events. This was used to investigate the injection process and beam losses. It was shown that the transverse feedback system increases the injection efficiency. Another aspect of this thesis is the improvement of the signal quality of ultrashort coherent synchrotron radiation pulses, which are generated by the short-pulse facility at DELTA. The short-pulse facility is based

  1. TFTR neutral beam injection system conceptual design

    International Nuclear Information System (INIS)

    Three subsystems are described in the following chapters: (1) Neutral Beam Injection Line; (2) Power Supplies; and (3) Controls. Each chapter contains two sections: (1) Functions and Design Requirements; this is a brief listing of the requirements of components of the subsystem. (2) Design Description; this section describes the design and cost estimates. The overall performance requirements of the neutral beam injection system are summarized. (MOW)

  2. Construction of ion beam pulse radiolysis system

    Energy Technology Data Exchange (ETDEWEB)

    Chitose, Norihisa; Katsumura, Yosuke; Domae, Masafumi; Ishigure, Kenkichi; Murakami, Takeshi [Tokyo Univ. (Japan)

    1996-10-01

    An ion beam pulse radiolysis system has been constructed at HIMAC facility. Ion beam of 24 MeV He{sup 2+} with the duration longer than 1 {mu}s is available for irradiation. Three kinds of aqueous solutions, (C{sub 6}H{sub 5}){sub 2}CO, NaHCO{sub 3} and KSCN, were irradiated and the absorption signals were observed. (author)

  3. Uplink Contention-Based CSI Feedback with Prioritized Layers for a Multi-Carrier System

    OpenAIRE

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar; Yomo, Hiroyuki; Sakai, Hideaki

    2011-01-01

    Optimized resource allocation of the Downlink (DL) in wireless systems utilizing Multi-Carrier (MC) transmission requires Channel State Information (CSI) feedback for each user/subchannel to the Base Station (BS), consuming a high amount of Uplink (UL) radio resources. To alleviate this problem, several works have considered contention-based CSI feedback in the UL control channel. We propose such a feedback scheme for a generic MC system, based on the idea of variable collision protection, wh...

  4. Uplink Contention-based CSI Feedback with Prioritized Layers for a Multi-Carrier System

    OpenAIRE

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar; Yomo, Hiroyuki; Sakai, Hideaki

    2012-01-01

    Optimized resource allocation of the Downlink (DL) in wireless systems utilizing Multi-Carrier (MC) transmission requires Channel State Information (CSI) feedback for each user/subchannel to the Base Station (BS), consuming a high amount of Uplink (UL) radio resources. To alleviate this problem, several works have considered contention-based CSI feedback in the UL control channel. We propose such a feedback scheme for a generic MC system, based on the idea of variable collision protection, wh...

  5. An image retrieval system based on explicit and implicit feedback on a tablet computer

    OpenAIRE

    Hu, Feiyan; Smeaton, Alan F.; Sun, Yan

    2012-01-01

    Our research aims at developing a image retrieval system which uses relevance feedback to build a hybrid search /recommendation system for images according to users’ inter ests. An image retrieval application running on a tablet computer gathers explicit feedback through the touchscreen but also uses multiple sensing technologies to gather implicit feedback such as emotion and action. A recommendation mechanism driven by collaborative filtering is implemented to verify our interaction design.

  6. Increasing Personal Value Congruence in Computerized Decision Support Using System Feedback

    OpenAIRE

    Bryan Hosack; David Paradice

    2014-01-01

    The Theory of Universals in Values (TUV), a reliable and validated conceptualization of personal values used in psychology, is used to examine the effect of system feedback delivered by a Decision Support System (DSS) on personal values. The results indicate that value-based decision-making behavior can be influenced by DSS feedback to address value congruence in decision-making. User behavior was shown to follow the outcomes expected by operant theory when feedback was supportive and to foll...

  7. The AGS Booster Beam Position Monitor system

    International Nuclear Information System (INIS)

    To accelerate both protons and heavy ions, the AGS Booster requires a broadband (multi-octave) beam position monitoring system with a dynamic range spanning several orders of magnitude (2 x 1010 to 1.5 x 1013 particles per pulse). System requirements include the ability to acquire single turn trajectory and average orbit information with ± 0.1 mm resolution. The design goal of ± 0.5 mm corrected accuracy requires that the detectors have repeatable linear performance after periodic bakeout at 300 degree C. The system design and capabilities of the Booster Beam Position Monitor will be described, and initial results presented. 7 refs., 5 figs

  8. The elettra beam line control system

    International Nuclear Information System (INIS)

    Elettra is a third generation Synchrotron Light Source located in Trieste (Italy). It consists of a full energy linac injector and a storage ring with beam energies between 1.5 and 2 GeV. The facility is scheduled to be operational by end 1993. For the whole project 22 beam lines from insertion devices are foreseen, each of them is composed of a large number of measurement and controls instruments, most of them embedded in intelligent devices; in addition each beam line can be considered unique compared to the others, having been designed to provide a different kind of synchrotron radiation. This results in a large not homogenous environment where more than 200,000 physical points have to be controlled. A joint team composed of Softeco Sismat and Digital Equipment has developed a fully automated beam line control system able to give full remote controls, with different kind of access rights, to beam line users and beam line specialists as well as a full integration with experiment control systems. ((orig.))

  9. Automatic local beam steering systems for NSLS X-Ray storage ring - Design and implementation

    International Nuclear Information System (INIS)

    Recently, two local automatic steering systems, controlled by microprocessors, have been installed and commissioned in the NSLS X-Ray storage ring. In each system, the position of the electron beam is stabilized at two locations by four independent servo systems. This paper describes three aspects of the local feedback program: (1) design, (2) commissioning and (3) limitation. The system design is explained by identifying major elements such as beam position detectors, signal processors, compensation amplifiers, ratio amplifiers, trim equalizers and microprocessor feedback controllers. System commissioning involves steps such as matching trim compensation, determination of local orbit bumps, measurement of open loop responses and design of servo circuits. Several limitations of performance are also discussed

  10. Neural networks for feedback feedforward nonlinear control systems.

    Science.gov (United States)

    Parisini, T; Zoppoli, R

    1994-01-01

    This paper deals with the problem of designing feedback feedforward control strategies to drive the state of a dynamic system (in general, nonlinear) so as to track any desired trajectory joining the points of given compact sets, while minimizing a certain cost function (in general, nonquadratic). Due to the generality of the problem, conventional methods are difficult to apply. Thus, an approximate solution is sought by constraining control strategies to take on the structure of multilayer feedforward neural networks. After discussing the approximation properties of neural control strategies, a particular neural architecture is presented, which is based on what has been called the "linear-structure preserving principle". The original functional problem is then reduced to a nonlinear programming one, and backpropagation is applied to derive the optimal values of the synaptic weights. Recursive equations to compute the gradient components are presented, which generalize the classical adjoint system equations of N-stage optimal control theory. Simulation results related to nonlinear nonquadratic problems show the effectiveness of the proposed method. PMID:18267810

  11. Upgrading of the beam diagnostic system of U-70 beam transfer lines

    CERN Document Server

    Kovaltsov, V I; Matyushin, A T; Milyutkin, V; Romanov, I; Seleznev, V; Sytin, A N; Clausen, M

    2001-01-01

    The beam diagnostic system of U-70 beam transfer lines (beam profiles, intensity and beam losses measurements) was designed in the beginning of 80-th on the base of 8-bit microprocessor, SUMMA hardware and home made serial communication link. Because of the maintenance problems the decision was taken to upgrade the hardware and software parts of the system.

  12. Development of a Computer Control System for Heavy Ion Beam Probes

    Science.gov (United States)

    Andersen, J. K.; Roberts, S. L.; Westervelt, E. R.; Schoch, P. M.; Schatz, J. G.

    1996-11-01

    Enhanced computer control of heavy ion beam probes would increase the reproducability of experimental conditions by automation and feedback control of some system parameters. Also, operation from a remote site would then be feasible. Computer control has been implemented on a variety of Rensselaer heavy ion beam probe systems. However, no system to date has allowed complete remote operation. This has been primarily due to the limitations of the user interface. The next generation of HIBP control systems software is being created with National Instruments' graphical language, LabVIEW. The virtual instruments allow detailed monitoring and control of the injected beam conditions. The control and monitoring of the ion beam, including filament current and Pierce, focusing, quadrupole lens, and sweep electrodes' voltages has been tested on RPI's vertical test stand. A feedback routine to focus the beam using the quadrupole lens is currently being developed. When this capability is available, it will be implemented on a heavy ion beam probe diagnostic operating on a magnetic confinement device.

  13. Opinion Analysis Using Domain Ontology for Implementing Natural Language Based Feedback System

    Directory of Open Access Journals (Sweden)

    Pratik K. Agrawal

    2014-02-01

    Full Text Available This paper proposes a natural language based feedback analysis system that extracts semantic relations from feedback data in order to map it with the domain ontology. After pre-processing a set of words or phrases are extracted from the input data. The data are analyzed semantically to interpret its meaning. This meaning is in an intermediate form which is then mapped to the terms defined in the ontology using similarity function. The opinion analysis of the semantic data is carried out for measuring the polarity of the feedback by the use of opinion analysis method. The system is evaluated on the input feedback data.

  14. Global feedback control of Turing patterns in network-organized activator-inhibitor systems

    Science.gov (United States)

    Hata, S.; Nakao, H.; Mikhailov, A. S.

    2012-06-01

    Results of the first systematic study on feedback control of nonequilibrium pattern formation in networks are reported. Effects of global feedback control on Turing patterns in network-organized activator-inhibitor system have been investigated. The feedback signal was introduced into one of the parameters of the system and was proportional to the amplitude of the developing Turing pattern. Without the control, the Turing instability corresponded to a subcritical bifurcation and hysteresis effects were observed. Sufficiently strong feedback control rendered, however, the bifurcation supercritical and eliminated the hysteresis effects.

  15. Improving Lectures and Practical Classes in Using an Automatically Feedback System.

    Science.gov (United States)

    Bollin, Andreas

    This paper presents a World Wide Web-based electronic feedback system for use in lectures and practical classes. The system is based on Java and provides a configurable feedback form, a managing tool for administrators, and a statistics viewer for presenting the generated statistical data in various ways. In addition, it generates a statistical…

  16. A Social Learning Management System Supporting Feedback for Incorrect Answers Based on Social Network Services

    Science.gov (United States)

    Son, Jiseong; Kim, Jeong-Dong; Na, Hong-Seok; Baik, Doo-Kwon

    2016-01-01

    In this research, we propose a Social Learning Management System (SLMS) enabling real-time and reliable feedback for incorrect answers by learners using a social network service (SNS). The proposed system increases the accuracy of learners' assessment results by using a confidence scale and a variety of social feedback that is created and shared…

  17. PERMANENCE OF A DISCRETE SINGLE SPECIES SYSTEM WITH DELAYS AND FEEDBACK CONTROL

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper,a discrete single species system with time delays and feedback control is considered.Sufficient conditions which guarantee the permanence of all positive solutions to this discrete system are obtained.The results show that the feedback control is harmless for the permanence of the species.

  18. Uplink Contention-based CSI Feedback with Prioritized Layers for a Multi-Carrier System

    DEFF Research Database (Denmark)

    Kaneko, Megumi; Hayashi, Kazunori; Popovski, Petar;

    2012-01-01

    , several works have considered contention-based CSI feedback in the UL control channel. We propose such a feedback scheme for a generic MC system, based on the idea of variable collision protection, where the probability that a feedback information experiences a collision depends on its importance. By......Optimized resource allocation of the Downlink (DL) in wireless systems utilizing Multi-Carrier (MC) transmission requires Channel State Information (CSI) feedback for each user/subchannel to the Base Station (BS), consuming a high amount of Uplink (UL) radio resources. To alleviate this problem...... partitioning the CSI into orthogonal layers of priority, and allocating different numbers of feedback slots to each layer, this scheme ensures that the feedback success probability is higher for the CSI with better quality, which is more likely to be used by the scheduler. Furthermore, we present a theoretical...

  19. Effects of Prediction Feedback on Three-Route Intelligent Traffic Systems

    CERN Document Server

    Chuan-Fei, Dong; Bing-Hong, Wang; Xiao-Yan, Sun

    2009-01-01

    The optimal information feedback has a significant effect on many socioeconomic systems like stock market and traffic systems aiming to make full use of resources. Recently, a feedback strategy named prediction feedback strategy(Dong\\emph{et al}. 2009 Physica A {\\bf 388}, 4651) has been investigated, based on a two-route scenario. In this paper, we studied dynamics of traffic flow with real-time information provided and the influence of prediction feedback strategy on a three-route scenario in which dynamic information can be generated and displayed on the board to guide road users to make a choice. In three-route scenario, our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting prediction feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e., vehicle number and flux.

  20. Beam developments for the Harwell microprobe system

    International Nuclear Information System (INIS)

    A consequence of the rapid development of micron and submicron size electronic devices is the diminished applicability of high energy ion microprobes with their present resolution limitations to the study of such components. Although submicron beams have been reported the available beam current is barely sufficiently for PIXE and is not adequate for RBS. This lack of lateral resolution is due to low beam brightness at the microprobe object and aberrations in the focussing elements. As part of a program to address these problems the Harwell microprobe lens has been relocated on a new 5 MV Laddertron accelerator. The increased brightness and improved stability of this facility has so far led to a reduction in beam size from 3x3 μm2 to about 2x2 μm2. The feasibility of using a liquid metal ion source has been examined with a view to achieving more substantial increases in brightness. While such sources have brightness approximately 105 times greater than conventional gaseous sources the highly divergent nature of the beam presents problems for the beam transport system. The use of a liquid metal source on the accelerator has been successfully demonstrated but it indicates the need for a special low aberration injection lens if brightness is to be maintained. (orig.)

  1. Beam developments for the Harwell microprobe system

    International Nuclear Information System (INIS)

    A consequence of the rapid development of micron and submicron size electronic devices is the diminished applicability of high energy ion microprobes with their present resolution limitations to the study of such components. Although submicron beams have been reported the available beam current is barely sufficiently for PIXE and is not adequate for RBS. This lack of lateral resolution is due to low beam brightness at the microprobe object and aberrations in the focusing elements. As part of a program to address these problems the Harwell microprobe lens has been relocated on a new 5 MV Laddertron accelerator. The increased brightness and improved stability of this facility has so far led to a reduction in beam size from 3 x 3 μm2 to about 2 x 2 μm2. The feasibility of using a liquid metal ion source has been examined with a view to achieving more substantial increases in brightness. While such sources have brightness approximately 105 times greater than conventional gaseous sources the highly divergent nature of the beam presents problems for the beam transport system. The use of a liquid metal source on the accelerator has been successfully demonstrated but it indicates the need for a special low aberration injection lens if brightness is to be maintained

  2. The Feedback Method. A System Dynamics Approach to Teaching Macroeconomics

    OpenAIRE

    Wheat, I. David

    2007-01-01

    This thesis documents a method for improving undergraduate instruction in macroeconomics. Called the feedback method, it enables students to learn about dynamic behavior in a market economy by using feedback loop diagrams and interactive computer simulation models instead of static graphs or differential equations. There are at least two types of pedagogical problems associated with graphical representation of the economy. First, students seem to have difficulty interpreting st...

  3. Amplified Feedback Mechanism of the Forests-Aerosols-Climate System

    Directory of Open Access Journals (Sweden)

    Thomas Hede

    2015-01-01

    Full Text Available Climate change very likely has effects on vegetation so that trees grow faster due to carbon dioxide fertilization (a higher partial pressure increases the rate of reactions with Rubisco during photosynthesis and that trees can be established in new territories in a warmer climate. This has far-reaching significance for the climate system mainly due to a number of feedback mechanisms still under debate. By simulating the vegetation using the Lund-Potsdam-Jena guess dynamic vegetation model, a territory in northern Russia is studied during three different climate protocols assuming a doubling of carbon dioxide levels compared to the year 1975. A back of the envelope calculation is made for the subsequent increased levels of emissions of monoterpenes from spruce and pine forests. The results show that the emissions of monoterpenes at the most northern latitudes were estimated to increase with over 500% for a four-degree centigrade increase protocol. The effect on aerosol and cloud formation is discussed and the cloud optical thickness is estimated to increase more than 2%.

  4. Robust MPC with Output Feedback of Integrating Systems

    Directory of Open Access Journals (Sweden)

    J. M. Perez

    2012-01-01

    Full Text Available In this work, it is presented a new contribution to the design of a robust MPC with output feedback, input constraints, and uncertain model. Multivariable predictive controllers have been used in industry to reduce the variability of the process output and to allow the operation of the system near to the constraints, where it is usually located the optimum operating point. For this reason, new controllers have been developed with the objective of achieving better performance, simpler control structure, and robustness with respect to model uncertainty. In this work, it is proposed a model predictive controller based on a nonminimal state space model where the state is perfectly known. It is an infinite prediction horizon controller, and it is assumed that there is uncertainty in the stable part of the model, which may also include integrating modes that are frequently present in the process plants. The method is illustrated with a simulation example of the process industry using linear models based on a real process.

  5. The AGS Booster beam loss monitor system

    International Nuclear Information System (INIS)

    A beam loss monitor system has been developed for the Brookhaven National Laboratory Booster accelerator, and is designed for use with intensities of up to 1.5 x 1013 protons and carbon to gold ions at 50-3 x 109 ions per pulse. This system is a significant advance over the present AGS system by improving the sensitivity, dynamic range, and data acquisition. In addition to the large dynamic range achievable, it is adaptively shifted when high losses are detected. The system uses up to 80 argon filled ion chambers as detectors, as well as newly designed electronics for processing and digitizing detector outputs. The hardware simultaneously integrates each detector output, interfaces to the beam interrupt systems, and digitizes all 80 channels to 21 bits at 170 KHz. This paper discuses the design, construction, and operation of the system. 4 refs., 2 figs

  6. Design of Main Control Console Software in EAST Neutral Beam Injector's Control System for the First Beam Line

    Science.gov (United States)

    Wu, De-Yun; Hu, Chun-Dong; Sheng, Peng; Zhao, Yuan-Zhe; Zhang, Xiao-Dan; Cui, Qing-Long

    2013-10-01

    Neutral beam injector is one of the main plasma heating and plasma current driving methods for experimental advanced superconducting tokomaks (EAST). In order to realize visual operation of EAST neutral beam injector's control system (NBICS), main control console (MCC) is developed to work as the human-machine interface between the NBICS and physical operator. It can meet the requirements of visual control of NBICS by providing a user graphic interface. With the specific algorithms, the setup of power supply sequence is relatively independent and simple. Displaying the real-time feedback of the subsystems provides a reference for operators to monitor the status of the system. The MCC software runs on a Windows system and uses C++ language code while using client/server (C/S) mode, multithreading and cyclic redundancy check technology. The experimental results have proved that MCC provides a stability and reliability operation of NBICS and works as an effective man-machine interface at the same time.

  7. Beam loss monitor system for the SSC

    International Nuclear Information System (INIS)

    At full intensity the energy contained in each beam of the Superconducting Super Collider (SSC) is 400 MJ. The loss of a small fraction of that beam has the potential to cause magnet quenches or even severe damage to Collider components. To help protect the machine a sensitive and reliable beam loss monitor (BLM) system must be designed and built. In fact, BLM systems will be needed for all the accelerators of the SSC. The BLM system requirements for each of these accelerators will be discussed, but emphasis will be placed on the Collider. The discussion will include the preliminary design of BLM systems, the considerations that led to these designs, the calculations that were performed in development of the designs, and the problems that remain to be solved. A major tool in the design process has been a series of Monte Carlo calculations that were used to estimate beam loss distributions for the Collider arcs, the interaction regions, and the west utility region. These calculations were also used to study the fluence as a function of energy, the particle content, and the dose rate at selected positions. Detailed considerations such as detector spacing and sensitivity, loss fluctuations, reliability, and maintainability will be discussed. The proposed preliminary BLM system design for the Collider uses a radiation-hard, solid-state ionization detector and fast analog-to-digital conversion. Details of this design and relevant options will be discussed

  8. Synthesis of dissipative output feedback controllers. Application to mechanical systems

    Energy Technology Data Exchange (ETDEWEB)

    Johannessen, Erling Aarsand

    1997-12-31

    This thesis presents new results on the synthesis of linear controllers with passivity, or more general, dissipativity properties. These methods may be applied to obtain more accurate control over mechanical systems and in the control of chemical processes that involve dissipative subsystems. The thesis presents two different approaches for synthesis of dissipative controllers: (1) A method that exploits the Riccati equation solution to the state space formulation of the H{sub {infinity}} control problem is investigated, illustrated by synthesising a controller for damping of flexible modes in a beam. (2) A more general method for dissipative control synthesis is developed that retains the well-known techniques of loop-shaping and frequency weighting in H{sub {infinity}}. A method is also presented for controller synthesis directly from frequency response data. 82 refs., 34 figs., 3 tabs.

  9. Low level RF systems for synchrotrons part II: High Intensity. Compensation of the beam induced effects

    CERN Document Server

    Baudrenghien, P

    2005-01-01

    The high intensity regime is reached when the voltage induced by the beam in the RF cavities is of an amplitude comparable to the desired accelerating voltage. In steady state this beam loading can be compensated by providing extra RF power. Transient beam loading occurs at injection or in the presence of a beam intensity that is not uniform around the ring. The transients are periodic at the revolution frequency. Without correction transient beam loading can be very harmful: The stable phase and bucket area will not be equal for all bunches. Strong beam loading often goes in pair with longitudinal instabilities because the RF cavities are a large contributor to the total ring impedance. The low level systems that reduce the effect of the transient beam loading will also increase the threshold intensity of the longitudinal instability caused by the cavity impedance at the fundamental RF frequency. Four classic methods are presented here: Feedforward, RF feedback, long delay feedback and bunch by bunch feedbac...

  10. pth Moment Exponential Stability of Stochastic PWM Feedback Systems with Time-Varying Delays

    OpenAIRE

    Zhang, Zhong; Ye, Lixia

    2012-01-01

    This paper further studies the pth moment exponential stability of stochastic pulse-width-modulated (PWM) feedback systems with distributed time-varying delays. We establish several globally exponential stability criteria for such PWM feedback systems by using Lyapunov-Krasovskii functional and then present an upper bound of the parameter of PWM when the system is stable and such system has stronger anti-interference performance than the system without time-varying delays. Furthermore, we pre...

  11. $p$ th Moment Exponential Stability of Stochastic PWM Feedback Systems with Time-Varying Delays

    OpenAIRE

    Zhong Zhang; Lixia Ye

    2012-01-01

    This paper further studies the $p$ th moment exponential stability of stochastic pulse-width-modulated (PWM) feedback systems with distributed time-varying delays. We establish several globally exponential stability criteria for such PWM feedback systems by using Lyapunov-Krasovskii functional and then present an upper bound of the parameter of PWM when the system is stable and such system has stronger anti-interference performance than the system without time-varying delays. Furthermore, we ...

  12. Time-delay feedback control in a delayed dynamical chaos system and its applications

    Science.gov (United States)

    Ye, Zhi-Yong; Yang, Guang; Deng, Cun-Bing

    2011-01-01

    The feedback control of a delayed dynamical system, which also includes various chaotic systems with time delays, is investigated. On the basis of stability analysis of a nonautonomous system with delays, some simple yet less conservative criteria are obtained for feedback control in a delayed dynamical system. Finally, the theoretical result is applied to a typical class of chaotic Lorenz system and Chua circuit with delays. Numerical simulations are also given to verify the theoretical results.

  13. ISR internal beam-dumping system

    CERN Multimedia

    1970-01-01

    Parts of the internal beam-dumping system. In the ring on the right are shown the four tanks containing the vertically deflecting magnets and in the ring on the left is the absorber block. Identical parts are on opposite sides in the other half of this intersection region.

  14. Systems analysis on laser beamed power

    Science.gov (United States)

    Zeiders, Glenn W., Jr.

    1993-01-01

    The NASA SELENE power beaming program is intended to supply cost-effective power to space assets via Earth-based lasers and active optics systems. Key elements of the program are analyzed, the overall effort is reviewed, and recommendations are presented.

  15. Operation and performance of a longitudinal feedback system using digital signal processing

    International Nuclear Information System (INIS)

    A programmable longitudinal feedback system using a parallel array of AT ampersand T 1610 digital signal processors has been developed as a component of the PEP-II R ampersand D program. This system has been installed at the Advanced Light Source (LBL) and implements full speed bunch by bunch signal processing for storage rings with bunch spacing of 4ns. Open and closed loop results showing the action of the feedback system are presented, and the system is shown to damp coupled-bunch instabilities in the ALS. A unified PC-based software environment for the feedback system operation is also described

  16. Feedback threshold with guaranteed QoS in multiuser OFDM systems

    Institute of Scientific and Technical Information of China (English)

    YANG Rui-zhe; YUAN Chao-wei; TENG Ying-lei; ZHANG Yan-hua

    2009-01-01

    A threshold setting scheme is proposed based on the resource management and limited feedback theory in multiuser orthogonal frequency division multiplexing (OFDM) systems. In adaptive resource allocation, the factors denoting the quality of service (QoS) and fairness are both considered as the user weight. From the aspect of feedback outage probability, the proposed algorithm sets the threshold for each user related to its weight, which brings enough feedback to the user with greater weight. Analysis and simulation results show that, compared with the threshold ignoring weights, the proposed scheme has much lower feedback load while with better QoS.

  17. Development of beam flattening system using non-linear beam optics at J-PARC/JSNS

    International Nuclear Information System (INIS)

    As increasing in the beam power, the damage of the target becomes serious. Especially for a target for high power short pulse spallation neutron source, the damage due to the proton beam on the target vessel for liquid metal target such as mercury is reported to be proportional of 4th power of the peak intensity of the proton beam. Reduction of the peak intensity is important for the beam injection system. At the JSNS, beam profile can be described by the clear Gaussian functions. To reduce peak intensity, we have developed a beam transport system by non-linear beam optics using octupole magnets. (author)

  18. Realistic RF system and Beam Simulation in Real Time for a Synchrotron

    CERN Document Server

    Tückmantel, Joachim

    2001-01-01

    Due to heavy beam loading with gaps in the LHC beams, RF and beam are intimately linked to a complex system with fast transients where the RF loops and their limitations play a decisive role. Such a system is difficult to assess with analytical methods. To learn about overall system stability and for the definition of RF components to be built it is essential to understand the complete system long before the machine really exists. Therefore the author has written a general purpose real time simulation program and applied it to model the LHC machine with its beam pattern and complete double RF system. The latter is equipped with fast RF vector feedback loops having loop delay, transmitter power limitation and limited amplifier bandwidth as well as including one-turn-delay feedback and longitudinal batch injection damping. The development of all RF and beam quantities can be displayed graphically turn by turn. These frames can be assembled to a realistic multi-trace scope movie.

  19. Ion beam pulse radiolysis system at HIMAC

    Energy Technology Data Exchange (ETDEWEB)

    Chitose, N.; Katsumura, Y.; Domae, M.; Ishigure, K. [Tokyo Univ. (Japan); Murakami, T.

    1997-03-01

    An ion beam pulse radiolysis system has been constructed at HIMAC facility. Ion beam of 24MeV He{sup 2+} with the duration longer than 1 {mu}s is available for irradiation. Three kinds of aqueous solutions, (C{sub 6}H{sub 5}){sub 2}CO, NaHCO{sub 3}, and KSCN, were irradiated and the absorption signals corresponding to (C{sub 6}H{sub 5}){sub 2}CO{sup -}, CO{sub 3}{sup -}, and (SCN){sub 2}{sup -} respectively were observed. Ghost signals which interfere with the measurement are also discussed. (author)

  20. Design of a feedback system to stabilise instabilities by ECRH using a combined ECW launcher and ECE receiver

    International Nuclear Information System (INIS)

    At the TEXTOR tokamak a 140 GHz, 800 kW, 10 s gyrotron is employed for studies on ECW heating and ECCD. A key program is the suppression of tearing modes, which is aided by the unique facility at TEXTOR to program magnetic structures during a discharge (DED). A scheme is under development which aims to detect the perturbations on the electron cyclotron emission caused by these instabilities via the same line of sight as is used by the ECRH beam, and to use this information for feedback control of the instability. A brief overview of TEXTOR and relevant island parameters is given as well as a description of the upgraded ECRH system. This is followed by a description of the design of the transmission line coupler and receiver for island detection which constitutes the main topic of the paper. The final section sketches the feedback controller that processes the receiver signals, and controls the moveable launcher and the gyrotron power

  1. Distributed User Selection in Network MIMO Systems with Limited Feedback

    KAUST Repository

    Elkhalil, Khalil

    2015-09-06

    We propose a distributed user selection strategy in a network MIMO setting with M base stations serving K users. Each base station is equipped with L antennas, where LM ≪ K. The conventional selection strategy is based on a well known technique called semi-orthogonal user selection when the zero-forcing beamforming (ZFBF) is adopted. Such technique, however, requires perfect channel state information at the transmitter (CSIT), which might not be available or need large feedback overhead. This paper proposes an alternative distributed user selection technique where each user sets a timer that is inversely proportional to his channel quality indicator (CQI), as a means to reduce the feedback overhead. The proposed strategy allows only the user with the highest CQI to respond with a feedback. Such technique, however, remains collision free only if the transmission time is shorter than the difference between the strongest user timer and the second strongest user timer. To overcome the situation of longer transmission times, the paper proposes another feedback strategy that is based on the theory of compressive sensing, where collision is allowed and all users encode their feedback information and send it back to the base-stations simultaneously. The paper shows that the problem can be formulated as a block sparse recovery problem which is agnostic on the transmission time, which makes it a good alternative to the timer approach when collision is dominant.

  2. Development of KSTAR Neutral Beam Heating System

    Energy Technology Data Exchange (ETDEWEB)

    Oh, B. H.; Song, W. S.; Yoon, B. J. (and others)

    2007-10-15

    The prototype components of a neutral beam injection (NBI) system have been developed for the KSTAR, and a capability of the manufactured components has been tested. High power ion source, acceleration power supply, other ion source power supplies, neutralizer, bending magnet for ion beam separation, calorimeter, and cryo-sorption pump have been developed by using the domestic technologies and tested for a neutral beam injection of 8 MW per beamline with a pulse duration of 300 seconds. The developed components have been continuously upgraded to achieve the design requirements. The development technology of high power and long pulse neutral beam injection system has been proved with the achievement of 5.2 MW output for a short pulse length and 1.6 MW output for a pulse length of 300 seconds. Using these development technologies, the domestic NB technology has been stabilized under the development of high power ion source, NB beamline components, high voltage and current power supplies, NB diagnostics, NB system operation and control.

  3. SU-E-J-196: Implementation of An In-House Visual Feedback System for Motion Management During Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: To describe an in-house video goggle feedback system for motion management during simulation and treatment of radiation therapy patients. Methods: This video goggle system works by splitting and amplifying the video output signal directly from the Varian Real-Time Position Management (RPM) workstation or TrueBeam imaging workstation into two signals using a Distribution Amplifier. The first signal S[1] gets reconnected back to the monitor. The second signal S[2] gets connected to the input of a Video Scaler. The S[2] signal can be scaled, cropped and panned in real time to display only the relevant information to the patient. The output signal from the Video Scaler gets connected to an HDMI Extender Transmitter via a DVI-D to HDMI converter cable. The S[2] signal can be transported from the HDMI Extender Transmitter to the HDMI Extender Receiver located inside the treatment room via a Cat5e/6 cable. Inside the treatment room, the HDMI Extender Receiver is permanently mounted on the wall near the conduit where the Cat5e/6 cable is located. An HDMI cable is used to connect from the output of the HDMI Receiver to the video goggles. Results: This video goggle feedback system is currently being used at two institutions. At one institution, the system was just recently implemented for simulation and treatments on two breath-hold gated patients with 8+ total fractions over a two month period. At the other institution, the system was used to treat 100+ breath-hold gated patients on three Varian TrueBeam linacs and has been operational for twelve months. The average time to prepare the video goggle system for treatment is less than 1 minute. Conclusion: The video goggle system provides an efficient and reliable method to set up a video feedback signal for radiotherapy patients with motion management

  4. Development of the beam extraction synchronization system at the Fermilab Booster

    International Nuclear Information System (INIS)

    The new beam extraction synchronization control system called “Magnetic Cogging” was developed at the Fermilab Booster and it replaces a system called “RF Cogging” as part of the Proton Improvement Plan (PIP).[1] The flux throughput goal for the PIP is 2.2×1017 protons per hour, which is double the present flux. The flux increase will be accomplished by doubling the number of beam cycles which, in turn, will double the beam loss in the Booster accelerator if nothing else is done. The Booster accelerates beam from 400 MeV to 8 GeV and extracts it to the Main Injector (MI) or Recycler Ring (RR). Cogging controls the beam extraction gap position which is created early in the Booster cycle and synchronizes the gap to the rising edge of the Booster extraction kicker and the MI/RR injection kicker. The RF Cogging system controls the gap position by changing only the radial position of the beam thus limiting the beam aperture and creating beam loss due to beam scraping. The Magnetic Cogging system controls the gap position with the magnetic field of the dipole correctors while the radial position feedback keeps the beam on a central orbit. Also with Magnetic Cogging the gap creation can occur earlier in the Booster cycle when the removed particles are at a lower energy. Thus Magnetic Cogging reduces the deposited energy of the lost particles (beam energy loss) and results in less beam loss activation. Energy loss was reduced by 40% by moving the gap creation energy from 700 MeV to 400 MeV when the Booster Cogging system was switched from RF Cogging to Magnetic Cogging in March 2015

  5. Development of the beam extraction synchronization system at the Fermilab Booster

    Science.gov (United States)

    Seiya, K.; Chaurize, S.; Drennan, C. C.; Pellico, W.; Sullivan, T.; Triplett, A. K.; Waller, A. M.

    2015-11-01

    The new beam extraction synchronization control system called "Magnetic Cogging" was developed at the Fermilab Booster and it replaces a system called "RF Cogging" as part of the Proton Improvement Plan (PIP).[1] The flux throughput goal for the PIP is 2.2×1017 protons per hour, which is double the present flux. The flux increase will be accomplished by doubling the number of beam cycles which, in turn, will double the beam loss in the Booster accelerator if nothing else is done. The Booster accelerates beam from 400 MeV to 8 GeV and extracts it to the Main Injector (MI) or Recycler Ring (RR). Cogging controls the beam extraction gap position which is created early in the Booster cycle and synchronizes the gap to the rising edge of the Booster extraction kicker and the MI/RR injection kicker. The RF Cogging system controls the gap position by changing only the radial position of the beam thus limiting the beam aperture and creating beam loss due to beam scraping. The Magnetic Cogging system controls the gap position with the magnetic field of the dipole correctors while the radial position feedback keeps the beam on a central orbit. Also with Magnetic Cogging the gap creation can occur earlier in the Booster cycle when the removed particles are at a lower energy. Thus Magnetic Cogging reduces the deposited energy of the lost particles (beam energy loss) and results in less beam loss activation. Energy loss was reduced by 40% by moving the gap creation energy from 700 MeV to 400 MeV when the Booster Cogging system was switched from RF Cogging to Magnetic Cogging in March 2015.

  6. Real-time system for studies of the effects of acoustic feedback on animal vocalizations.

    Directory of Open Access Journals (Sweden)

    Mike eSkocik

    2013-01-01

    Full Text Available Studies of behavioral and neural responses to distorted auditory feedback can help shed light on the neural mechanisms of animal vocalizations. We describe an apparatus for generating real-time acoustic feedback. The system can very rapidly detect acoustic features in a song and output acoustic signals if the detected features match the desired acoustic template. The system uses spectrogram-based detection of acoustic elements. It is low-cost and can be programmed for a variety of behavioral experiments requiring acoustic feedback or neural stimulation. We use the system to study the effects of acoustic feedback on birds' vocalizations and demonstrate that such an acoustic feedback can cause both immediate and long-term changes to birds’ songs.

  7. Increasing Personal Value Congruence in Computerized Decision Support Using System Feedback

    Directory of Open Access Journals (Sweden)

    Bryan Hosack

    2014-02-01

    Full Text Available The Theory of Universals in Values (TUV, a reliable and validated conceptualization of personal values used in psychology, is used to examine the effect of system feedback delivered by a Decision Support System (DSS on personal values. The results indicate that value-based decision-making behavior can be influenced by DSS feedback to address value congruence in decision-making. User behavior was shown to follow the outcomes expected by operant theory when feedback was supportive and to follow the outcomes of reactance theory when feedback was challenging. This result suggests that practitioners and Information System (IS researchers should consider user values when designing computerized decision feedback to adjust a system’s design such that the potential user backlash is avoided or congruence between organizational and personal values is achieved.

  8. Finite-time stabilisation of simple mechanical systems using continuous feedback

    Science.gov (United States)

    Sanyal, Amit K.; Bohn, Jan

    2015-04-01

    Stabilisation of simple mechanical systems in finite time with continuous state feedback is considered here. The dynamics are represented by generalised (local) coordinates. A general methodology to construct control Lyapunov functions that are Hölder continuous and that can be used to show finite-time stability of the feedback controlled system, is presented. This construction also gives the feedback control law, and results in the feedback system being Hölder continuous as well. Unlike Lipschitz continuous feedback control systems, the feedback control scheme given here converges to the desired equilibrium in finite time. Moreover, unlike discontinuous and hybrid control schemes, the feedback control law does not lead to chattering in the presence of measurement noise, does not excite unmodelled high-frequency dynamics, and can be implemented with actuators that can only deliver continuous control inputs. The advantages of continuous finite-time stabilisation over continuous asymptotic stabilisation of mechanical systems, has been described in some prior research on finite-time stabilisation of the double integrator. The finite-time stabilisation scheme given here generalises this prior research to multiple degree-of-freedom mechanical systems. A numerical comparison is carried out through numerical simulations on two example systems that are representative of a broad class of simple mechanical systems.

  9. Using Instant Feedback System and Micro Exams to Enhance Active Learning

    Science.gov (United States)

    Sabag, N.; Kosolapov, S.

    2012-01-01

    This paper presents the outcomes of the preliminary survey in which the method of IFS was used to integrate motivating questions into the lecture presentations in order to increase the students' involvement. Instant Feedback System (IFS) enables the educators to improve their own teaching by getting instant and real-time feedback about how clear…

  10. A Moral Experience Feedback Loop: Modeling a System of Moral Self-Cultivation in Everyday Life

    Science.gov (United States)

    Sherblom, Stephen A.

    2015-01-01

    This "systems thinking" model illustrates a common feedback loop by which people engage the moral world and continually reshape their moral sensibility. The model highlights seven processes that collectively form this feedback loop: beginning with (1) one's current moral sensibility which shapes processes of (2) perception, (3)…

  11. Market factors feedback system of the pilot program of the Energy Extension Service

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-04-01

    The market factors feedback system of the pilot program of the Energy Extension Service are described. The description contains the plans of the 10 pilot EES states and the DOE for operating the system between December 1977 and March 1979. Chapter one contains the planned scope of the market factors feedback system during the pilot program: the target audiences, program services, likely topics of market factors feedback, and energy decision makers. Chapter two presents how the market factors feedback system will operate over the pilot program period. Chapter three summarizes the roles and functions of DOE/EXT in supporting state EES market factors feedback operations and in evaluating the program. There are three appendices. Appendix A contains the market factors feedback plans of the pilot EES states. Appendix B describes how DOE/EXT will work with national-level energy decision makers on market factors feedback received from state EESs. Appendix C is the design for the formal evaluation of the market factors feedback component of the pilot EES program. (MCW)

  12. Conception and realisation of a system for the automatic alignment of a CO2 laser beam

    International Nuclear Information System (INIS)

    The present paper deals with the continuous control of the direction of a CO2 laser beam, with a view to laser machining. Slow deviations, due to the cavity instability, move away the beam from the focusing system axis. An automatic alignment device acting on the last flat mirror of the optical line has been designed. This mirror is actuated by 2 motors which vary its inclination in 2 directions x,y. The first part of the present paper deals with the alignment principle worked according to the specific constraints to be faced and to the characteristics of the beam. It uses the revolution symmetry of the energy distribution of the beam: 4 thermocouples surrounding the beam on a same circumference yield equals signals if the beam is centered onto the 4 sensors. An angular displacement is characterised by the difference between the signals of 2 opposed detectors. The second part presents the digital feedback system: the divergence or the beam is computed from the differential signal by a coefficient K experimentally valued. The motor commands proceed from optical geometry laws. The filtering of the thermocouple signals is necessary in order to sort the slowly changing signal related to the beam displacement, from the higher frequency signal related to the laser system instability. The system has been implemented on a 16 bit microprocessor. (author)

  13. Effects of error feedback on a nonlinear bistable system with stochastic resonance

    International Nuclear Information System (INIS)

    In this paper, we discuss the effects of error feedback on the output of a nonlinear bistable system with stochastic resonance. The bit error rate is employed to quantify the performance of the system. The theoretical analysis and the numerical simulation are presented. By investigating the performances of the nonlinear systems with different strengths of error feedback, we argue that the presented system may provide guidance for practical nonlinear signal processing

  14. Efficient Third-Order Distributed Feedback Laser with Enhanced Beam Pattern

    Science.gov (United States)

    Hu, Qing (Inventor); Lee, Alan Wei Min (Inventor); Kao, Tsung-Yu (Inventor)

    2015-01-01

    A third-order distributed feedback laser has an active medium disposed on a substrate as a linear array of segments having a series of periodically spaced interstices therebetween and a first conductive layer disposed on a surface of the active medium on each of the segments and along a strip from each of the segments to a conductive electrical contact pad for application of current along a path including the active medium. Upon application of a current through the active medium, the active medium functions as an optical waveguide, and there is established an alternating electric field, at a THz frequency, both in the active medium and emerging from the interstices. Spacing of adjacent segments is approximately half of a wavelength of the THz frequency in free space or an odd integral multiple thereof, so that the linear array has a coherence length greater than the length of the linear array.

  15. RHIC beam loss monitor system design

    International Nuclear Information System (INIS)

    The Beam Loss Monitor (BLM) System is designed to prevent the quenching of RHIC magnets due to beam loss, provide quantitative loss data, and the loss history in the event of a beam abort. The system uses 400 ion chambers of a modified Tevatron design. To satisfy fast (single turn) and slow (100 msec) loss beam criteria and provide sensitivity for studies measurements, a range of over 8 decades is needed. An RC pre-integrator reduces the dynamic range for a low current amplifier. This is digitized for data logging. The output is also applied to an analog multiplier which compensates the energy dependence, extending the range of the abort comparators. High and low pass filters separate the signal to dual comparators with independent programmable trip levels. Up to 64 channels, on 8 VME boards, are controlled by a micro-controller based VME module, decoupling it from the front-end computer (FEC) for real-time operation. Results with the detectors in the RHIC Sextant Test and the electronics in the AGS-to-RHIC (AtR) transfer line will be presented

  16. Effect of biased feedback on motor imagery learning in BCI-teleoperation system

    Directory of Open Access Journals (Sweden)

    Maryam eAlimardani

    2014-04-01

    Full Text Available Feedback design is an important issue in motor imagery BCI systems. Regardless, to date it has not been reported how feedback presentation can optimize co-adaptation between a human brain and such systems. This paper assesses the effect of realistic visual feedback on users’ BC performance and motor imagery skills. We previously developed a tele-operation system for a pair of humanlike robotic hands and showed that BCI control of such hands along with first-person perspective visual feedback of movements can arouse a sense of embodiment in the operators. In the first stage of this study, we found that the intensity of this ownership illusion was associated with feedback presentation and subjects’ performance during BCI motion control. In the second stage, we probed the effect of positive and negative feedback bias on subjects’ BCI performance and motor imagery skills. Although the subject specific classifier, which was set up at the beginning of experiment, detected no significant change in the subjects’ online performance, evaluation of brain activity patterns revealed that subjects’ self-regulation of motor imagery features improved due to a positive bias of feedback and a possible occurrence of ownership illusion. Our findings suggest that in general training protocols for BCIs, manipulation of feedback can play an important role in the optimization of subjects’ motor imagery skills.

  17. Effect of neutronic feedback on flow instability of parallel double-channel natural circulation system

    International Nuclear Information System (INIS)

    The thermal-hydraulic system code RELAP5 was coupled with the TDOT-T 3D neutron kinetic code by parallel virtual machine (PVM). A parallel double-channel natural circulation boiling system was built by the coupled code and the instability boundary of the system was obtained. Two types of fuel with different geometries (flat plate-type fuel and pin-type fuel) were used in the analysis respectively, and the influences of neutronic feedback on density wave instability were analyzed. For the flat-plate type fuel system, it is found that the type 1 density wave oscillation (DWO) is suppressed by neutronic feedback significantly but the effect of neutronic feedback on type 2 DWO is weak. For the pin-type fuel system, the result shows that the effect of neutronic feedback on instability boundary of the system could be ignored. (authors)

  18. Real time global orbit feedback system for NSLS x-ray ring

    International Nuclear Information System (INIS)

    We report on the design and commissioning of a real time harmonic global orbit feedback system for the NSLS X-ray ring. This system uses 8 pick-up electrode position monitors and 16 trim dipole magnets to eliminate 3 harmonic components of the orbit fluctuations. Because of the larger number of position monitors and trim magnets, the X-ray ring feedback system differs from the previously reported VUV ring system in that the Fourier analysis and harmonic generation networks are comprised of MDAC boards controlled by computer. The implementation of the global feedback system has resulted in a dramatic improvement of orbit stability, by more than a factor of five everywhere. Simultaneous operation of the global and several local bump feedback systems has been achieved. 4 refs., 5 figs

  19. A Selfish Linear Precoding Strategy for Downlink Two-User MIMO Systems Using Limited Rate Feedback

    Directory of Open Access Journals (Sweden)

    Lei Lv

    2013-07-01

    Full Text Available This letter proposes a limited feedback-based selfish linear precoding (SLP strategy for downlink two-user MIMO systems. In the proposed strategy, each user selfishly chooses the other user’s precoding matrix which minimizes its capacity loss. The proposed SLP strategy has two advantages comparing with traditional linear precoding strategies. First, SLP improves the system capacity by resisting interference more effectively. Second, the computing complexity of transmitter is reduced since the base station needs not to calculate precoding matrix. Simulation results verify the effectiveness of SLP on system capacity improvement comparing to limited feedback block diagonalization (LFBD algorithm, especially when feedback bits are insufficient.

  20. ℋ∞ constant gain state feedback stabilization of stochastic hybrid systems with Wiener process

    Directory of Open Access Journals (Sweden)

    E. K. Boukas

    2004-01-01

    Full Text Available This paper considers the stabilization problem of the class of continuous-time linear stochastic hybrid systems with Wiener process. The ℋ∞ state feedback stabilization problem is treated. A state feedback controller with constant gain that does not require access to the system mode is designed. LMI-based conditions are developed to design the state feedback controller with constant gain that stochastically stabilizes the studied class of systems and, at the same time, achieve the disturbance rejection of a desired level. The minimum disturbance rejection is also determined. Numerical examples are given to show the usefulness of the proposed results.

  1. OpenEssayist: real-life testing of an automated feedback system for draft essay writing

    OpenAIRE

    Whitelock, Denise; Twiner, Alison; Richardson, John T. E.; Field, Debora; Pulman, Stephen

    2014-01-01

    OpenEssayist is unique in being an automated feedback system that has been developed to offer feedback on students' draft essays, rather than assessment on their finished work. This is therefore a system that offers opportunities for students to engage with and reflect on their work, and to improve their work through understanding of the requirements of academic essay writing. In trialling use of the system in a genuine Open University course, we found that students made use of it to varying...

  2. Synchronization of coupled FitzHugh-Nagumo systems via MIMO feedback linearization control

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Ting [School of Electrical and Automation Engineering, Tianjin University, Tianjin 300072 (China); Wang Jiang [School of Electrical and Automation Engineering, Tianjin University, Tianjin 300072 (China)]. E-mail: jiangwang@tju.edu.cn; Fei Xiangyang [School of Electrical and Automation Engineering, Tianjin University, Tianjin 300072 (China); Deng Bin [School of Electrical and Automation Engineering, Tianjin University, Tianjin 300072 (China)

    2007-07-15

    In this paper, synchronization dynamics of two FitzHugh-Nagumo neurons electrically coupled with gap junction in external electrical stimulation is studied. In order to synchronize all state variables in the neuron system, we regard the nonlinear feedback system as a multi-input multi-output (MIMO) system. Then, a MIMO decoupling feedback linearization algorithm and an adaptive strategy are introduced respectively to design the synchronization controllers for the two coupled neurons. Numerical simulations demonstrate the effectiveness of the developed methods.

  3. Indexing system for optical beam steering

    Science.gov (United States)

    Sullivan, Mark T.; Cannon, David M.; Debra, Daniel B.; Young, Jeffrey A.; Mansfield, Joseph A.; Carmichael, Roger E.; Lissol, Peter S.; Pryor, G. M.; Miklosy, Les G.; Lee, Jeffrey H.

    1990-01-01

    This paper describes the design and testing of an indexing system for optical-beam steering. The cryogenic beam-steering mechanism is a 360-degree rotation device capable of discrete, high-precision alignment positions. It uses low-precision components for its rough alignment and kinematic design to meet its stringent repeatability and stability requirements (of about 5 arcsec). The principal advantages of this design include a decoupling of the low-precision, large angular motion from the high-precision alignment, and a power-off alignment position that potentially extends the life or hold time of cryogenic systems. An alternate design, which takes advantage of these attributes while reducing overall motion, is also presented. Preliminary test results show the kinematic mount capable of sub-arc second repeatability.

  4. Analysis, Design, and Evaluation of Acoustic Feedback Cancellation Systems for Hearing Aids

    DEFF Research Database (Denmark)

    Guo, Meng

    2013-01-01

    Acoustic feedback problems occur when the output loudspeaker signal of an audio system is partly returned to the input microphone via an acoustic coupling through the air. This problem often causes significant performance degradations in applications such as public address systems and hearing aids....... In the worst case, the audio system becomes unstable and howling occurs. In this work, first we analyze a general multiple microphone audio processing system, where a cancellation system using adaptive filters is used to cancel the effect of acoustic feedback. We introduce and derive an accurate...... estimation problem in acoustic feedback cancellation for hearing aids. It utilizes a probe noise signal which is generated with a specific characteristic so that it can facilitate an unbiased adaptive filter estimation with fast tracking of feedback path variations/changes despite its low signal level. We...

  5. Ion beam figuring system in NUDT

    Science.gov (United States)

    Zhou, Lin; Xie, Xuhui; Dai, Yifan; Jiao, Changjun; Li, Shengyi

    2007-12-01

    Ion beam figuring (IBF) is an optical fabrication technique that provides highly deterministic process to correct surface figure error of previously polished surfaces by using a directed, inert and neutralized ion beam to physically sputter material from the optic surface. Recently, an ion beam figuring system KDIFS-500 has been designed and built in National University of Defense Technology (NUDT) of the P.R. China. KDIFS-500 is capable of processing workpiece up to Φ500mm. Line scanning process was discussed in detail for estimating the parameters of the beam removal function (BRF) in process. Experiments were conducted to demonstrate that the BRF increases gradually in process and by employing a stability control, the BRF can be kept stable in process. Finally, a Φ95 mm plano optical sample of CVD coated SiC substrate has been figured in two process iterations for demonstrating the correction capability of the KDIFS-500. Their figure convergence ratios reached 5.8 and 2.1 respectively. The actual figure residual errors were basically consistent with the predicted error. These consistencies indicated that the IBF processes on KDIFS-500 are predictable deterministic processes.

  6. Neutral particle beam distributed data acquisition system

    Energy Technology Data Exchange (ETDEWEB)

    Daly, R.T.; Kraimer, M.R.; Novick, A.H.

    1987-01-01

    A distributed data acquisition system has been designed to support experiments at the Argonne Neutral Particle Beam Accelerator. The system uses a host VAXstation II/GPX computer acting as an experimenter's station linked via Ethernet with multiple MicroVAX IIs and rtVAXs dedicated to acquiring data and controlling hardware at remote sites. This paper describes the hardware design of the system, the applications support software on the host and target computers, and the real-time performance.

  7. Beam dynamics in the SLC final focus system

    International Nuclear Information System (INIS)

    The SLC luminosity is reached by colliding beams focused to about 2 μm transverse sizes. The Final Focus System (FFS) must enable, beyond its basic optical design, the detection and correction of errors accumulated in the system. In this paper, after summarizing the design, we review the sensitivity to such errors and the ability to correct them. The overall tuning strategy involves three phases: single beam spot minimization, steering the beams in collision and luminosity optimization with beam-beam effects

  8. Beam loading

    CERN Document Server

    Gamp, Alexander

    2013-01-01

    We begin by giving a description of the radio-frequency generator-cavity-beam coupled system in terms of basic quantities. Taking beam loading and cavity detuning into account, expressions for the cavity impedance as seen by the generator and as seen by the beam are derived. Subsequently methods of beam-loading compensation by cavity detuning, radio-frequency feedback and feedforward are described. Examples of digital radio-frequency phase and amplitude control for the special case of superconducting cavities are also given. Finally, a dedicated phase loop for damping synchrotron oscillations is discussed.

  9. Beam diagnostics and data acquisition system for ion beam transport line used in applied research

    International Nuclear Information System (INIS)

    Ion beam transport line for applied research on U-400 cyclotron, beam diagnostics and data acquisition system for condensed matter studies are described. The main features of Windows-based real time program are considered

  10. Colliding beam fusion reactor space propulsion system

    Science.gov (United States)

    Wessel, Frank J.; Binderbauer, Michl W.; Rostoker, Norman; Rahman, Hafiz Ur; O'Toole, Joseph

    2000-01-01

    We describe a space propulsion system based on the Colliding Beam Fusion Reactor (CBFR). The CBFR is a high-beta, field-reversed, magnetic configuration with ion energies in the range of hundreds of keV. Repetitively-pulsed ion beams sustain the plasma distribution and provide current drive. The confinement physics is based on the Vlasov-Maxwell equation, including a Fokker Planck collision operator and all sources and sinks for energy and particle flow. The mean azimuthal velocities and temperatures of the fuel ion species are equal and the plasma current is unneutralized by the electrons. The resulting distribution functions are thermal in a moving frame of reference. The ion gyro-orbit radius is comparable to the dimensions of the confinement system, hence classical transport of the particles and energy is expected and the device is scaleable. We have analyzed the design over a range of 106-109 Watts of output power (0.15-150 Newtons thrust) with a specific impulse of, Isp~106 sec. A 50 MW propulsion system might involve the following parameters: 4-meters diameter×10-meters length, magnetic field ~7 Tesla, ion beam current ~10 A, and fuels of either D-He3,P-B11,P-Li6,D-Li6, etc. .

  11. Internally shielded beam transport and support system

    International Nuclear Information System (INIS)

    Due to environmental concerns, the Advanced Photon Source has a policy that disallows any exposed lead within the facility. This creates a real problem for the beam transport system, not so much for the pipe but for the flexible coupling (bellows) sections. A complete internally shielded x-ray transport system, consisting of long transport lines joined by flexible coupling sections, has been designed for CARS sector 14 to operate either at high vacuum or as a helium flight tube. It can effectively shield against air scattering of wiggler or undulator white beam with proper placement of apertures, collimators, and masks for direct beam control. The system makes use of male- and female-style fittings that create a labyrinth allowing for continuous shielding through the flexible coupling sections. These parts are precision machined from a ternary hypereutectic lead alloy (cast under 15 inches of head pressure to assure a pinhole-free casting) then pressed into either end (rotatable vacuum flanges) of the bellows assembly. The transport pipe itself consists of a four part construction using a stepped transition ring (Z-ring) to connect an inner tube to the vacuum flange and also to a protective and supportive outer tube. The inner tube is wrapped with 1/16 double-prime pure lead sheet to a predetermined thickness following the shape of the stepped transition ring for continuous shielding. This design has been prototyped and radiation tested. copyright 1996 American Institute of Physics

  12. Distinct noise-controlling roles of multiple negative feedback mechanisms in a prokaryotic operon system.

    Science.gov (United States)

    Nguyen, L K; Kulasiri, D

    2011-03-01

    Molecular fluctuations are known to affect dynamics of cellular systems in important ways. Studies aimed at understanding how molecular systems of certain regulatory architectures control noise therefore become essential. The interplay between feedback regulation and noise has been previously explored for cellular networks governed by a single negative feedback loop. However, similar issues within networks consisting of more complex regulatory structures remain elusive. The authors investigate how negative feedback loops manage noise within a biochemical cascade concurrently governed by multiple negative feedback loops, using the prokaryotic tryptophan (trp) operon system in Escherechia coli as the model system. To the authors knowledge, this is the first study of noise in the trp operon system. They show that the loops in the trp operon system possess distinct, even opposing, noise-controlling effects despite their seemingly analogous feedback structures. The enzyme inhibition loop, although controlling the last reaction of the cascade, was found to suppress noise not only for the tryptophan output but also for other upstream components. In contrast, the Repression (Rep) loop enhances noise for all systems components. Attenuation (Att) poses intermediate effects by attenuating noise for the upstream components but promoting noise for components downstream of its target. Regarding noise at the output tryptophan, Rep and Att can be categorised as noise-enhancing loops whereas Enzyme Inhibition as a noise-reducing loop. These findings suggest novel implications in how cellular systems with multiple feedback mechanisms control noise. [Includes supplementary material]. PMID:21405203

  13. Issues on stability of ADP feedback controllers for dynamical systems.

    Science.gov (United States)

    Balakrishnan, S N; Ding, Jie; Lewis, Frank L

    2008-08-01

    This paper traces the development of neural-network (NN)-based feedback controllers that are derived from the principle of adaptive/approximate dynamic programming (ADP) and discusses their closed-loop stability. Different versions of NN structures in the literature, which embed mathematical mappings related to solutions of the ADP-formulated problems called "adaptive critics" or "action-critic" networks, are discussed. Distinction between the two classes of ADP applications is pointed out. Furthermore, papers in "model-free" development and model-based neurocontrollers are reviewed in terms of their contributions to stability issues. Recent literature suggests that work in ADP-based feedback controllers with assured stability is growing in diverse forms. PMID:18632377

  14. Feedback: Theory and Accelerator Applications

    Science.gov (United States)

    Himel, T.

    The use of feedback to stabilize the beam and improve the performance of accelerators is becoming more common. The methods used to design the feedback algorithms are introduced and some practical implementation details are described. The design of a PID loop using classical control techniques is covered as is the design of an optimal controller using modern control theory. Some adaptive control techniques are also briefly described. Examples are given of multiple-input-multiple-output loops and of how to handle systems of many interacting feedback loops.

  15. Neutral Beam Power System for TPX

    International Nuclear Information System (INIS)

    The Tokamak Physics Experiment (TPX) will utilize to the maximum extent the existing Tokamak Fusion Test Reactor (TFTR) equipment and facilities. This is particularly true for the TFTR Neutral Beam (NB) system. Most of the NB hardware, plant facilities, auxiliary sub-systems, power systems, service infrastructure, and control systems can be used as is. The major changes in the NB hardware are driven by the new operating duty cycle. The TFTR Neutral Beam was designed for operation of the Sources for 2 seconds every 150 seconds. The TPX requires operation for 1000 seconds every 4500 seconds. During the Conceptual Design Phase of TPX every component of the TFTR NB Electrical Power System was analyzed to verify whether the equipment can meet the new operational requirements with our without modifications. The Power System converts 13.8 kV prime power to controlled pulsed power required at the NB sources. The major equipment involved are circuit breakers, auto and rectifier transformers surge suppression components, power tetrodes, HV Decks, and HVDC power transmission to sources. Thermal models were developed for the power transformers to simulate the new operational requirements. Heat runs were conducted for the power tetrodes to verify capability. Other components were analyzed to verify their thermal limitations. This paper describes the details of the evaluation and redesign of the electrical power system components to meet the TPX operational requirements

  16. On Acoustic Feedback Cancellation Using Probe Noise in Multiple-Microphone and Single-Loudspeaker Systems

    DEFF Research Database (Denmark)

    Guo, Meng; Elmedyb, Thomas Bo; Jensen, Søren Holdt;

    2012-01-01

    acoustic feedback cancellation is carried out using a probe noise signal. The derived results show how different system parameters and signal properties affect the cancellation performance, and the results explain theoretically the decreased convergence rate. Understanding this is important for making......A probe noise signal can be used in an acoustic feedback cancellation system to prevent biased adaptive estimation of acoustic feedback paths. However, practical experiences and simulation results indicate that when-ever a low-level and inaudible probe noise signal is used, the convergence rate of...

  17. Design and technical construction of a tactile display for sensory feedback in a hand prosthesis system

    Directory of Open Access Journals (Sweden)

    Antfolk Christian

    2010-09-01

    Full Text Available Abstract Background The users of today's commercial prosthetic hands are not given any conscious sensory feedback. To overcome this deficiency in prosthetic hands we have recently proposed a sensory feedback system utilising a "tactile display" on the remaining amputation residual limb acting as man-machine interface. Our system uses the recorded pressure in a hand prosthesis and feeds back this pressure onto the forearm skin. Here we describe the design and technical solution of the sensory feedback system aimed at hand prostheses for trans-radial/humeral amputees. Critical parameters for the sensory feedback system were investigated. Methods A sensory feedback system consisting of five actuators, control electronics and a test application running on a computer has been designed and built. Firstly, we investigate which force levels were applied to the forearm skin of the user while operating the sensory feedback system. Secondly, we study if the proposed system could be used together with a myoelectric control system. The displacement of the skin caused by the sensory feedback system would generate artefacts in the recorded myoelectric signals. Accordingly, EMG recordings were performed and an analysis of the these are included. The sensory feedback system was also preliminarily evaluated in a laboratory setting on two healthy non-amputated test subjects with a computer generating the stimuli, with regards to spatial resolution and force discrimination. Results We showed that the sensory feedback system generated approximately proportional force to the angle of control. The system can be used together with a myoelectric system as the artefacts, generated by the actuators, were easily removed using a simple filter. Furthermore, the application of the system on two test subjects showed that they were able to discriminate tactile sensation with regards to spatial resolution and level of force. Conclusions The results of these initial experiments

  18. Student Feedback. The cornerstone to an effective quality assurance system in higher education

    OpenAIRE

    Maria Wolters

    2011-01-01

    Maria Wolters recenserar:Student Feedback. The cornerstone to an effective quality assurance system in higher education, av Nair, C.S. & Mertova, P. (båda red. och författare), Chandos Publishing (Oxford) Ltd

  19. Computer realization of feedback control system on HT-7 super-conduct tokamak poloidal field

    International Nuclear Information System (INIS)

    The author introduces the feedback control realization of poloidal field on HT-7 superconducting tokamak. It describes signal acquisition, data communication in the system. The block diagram of computer program is also given

  20. Effectiveness of a measurement feedback system on outcome in rheumatoid arthritis: a controlled clinical trial

    OpenAIRE

    Fransen, J.; Stucki, G.; Twisk, J.; Chamot, A; Gerster, J; Langenegger, T; Seitz, M; Michel, B.; m the,

    2003-01-01

    Background: With the help of a measurement feedback system, the treatment strategy for individual patients with rheumatoid arthritis (RA) can be adjusted to achieve optimal control of disease activity.

  1. Feedback Control in a General Almost Periodic Discrete System of Plankton Allelopathy

    OpenAIRE

    Wenshuang Yin

    2014-01-01

    We study the properties of almost periodic solutions for a general discrete system of plankton allelopathy with feedback controls and establish a theorem on the uniformly asymptotic stability of almost periodic solutions.

  2. High Power RF Test of the Digital Feedback Control System for the PEFP Accelerator

    International Nuclear Information System (INIS)

    To control the RF field in the accelerating cavity for the PEFP (Proton Engineering Frontier Project) proton accelerator, a digital feedback control system has been developed. The stability requirements of the RF field are ±1% in amplitude and ± .deg. in phase. The digital feedback control system is based on the commercial FPGA PMC board hosted in VME board. The analog front-end was also developed which contains the IQ modulator, RF mixer, attenuators etc. To check the performance of the digital feedback control system, low power test with a dummy cavity has been performed with an intentional perturbation and shown that the feedback system rejected the perturbation as expected. High power RF test with a klystron has been performed and an accelerating field profile was measured. In addition, the pulse-to-pulse stability was checked by pulse operation with 0.1 Hz repetition rate. The detailed high power test results will be given in this paper

  3. General Purpose Digital Signal Processing VME-Module for 1-Turn Delay Feedback Systems of the CERN Accelerator Chain

    CERN Document Server

    Rossi, V

    2010-01-01

    In the framework of the LHC project and the modifications of the SPS as its injector, the concept has been developed of a global digital signal processing unit (DSPU) that implements in numerical form the architecture of low-level RF systems. Since 2002 a Digital Notch Filter with programmable delay for the SPS Transverse Damper has been fully operational with fixed target and LHC-type beams circulating in the SPS. The approach, using an FPGA as core for the low-level system, is very flexible and allows the upgrade of the signal processing by modification of the original firmware. The development for the LHC 1-Turn delay Feedback has benefited from the same methodology and similar technology. The achieved performances of the LHC 1-Turn delay Feedback are compared with project requirements. The project flow for the recent LHC 1-T Feedback allows synergy with several other applications. The CERN PS Transverse Damper DSPU, with automatic delay compensation adapting the loop delay to the time of flight of the par...

  4. Distinct noise-controlling roles of multiple negative feedback mechanisms in a prokaryotic operon system

    OpenAIRE

    Nguyen, Lan K.; D. Kulasiri

    2011-01-01

    Molecular fluctuations are known to affect dynamics of cellular systems in important ways. Studies aimed at understanding how molecular systems of certain regulatory architectures control noise therefore become essential. The interplay between feedback regulation and noise has been previously explored for cellular networks governed by a single negative feedback loop. However, similar issues within networks consisting of more complex regulatory structures remain elusive. The authors investigat...

  5. On symmetries of nonlinear systems in state representation and application of invariant feedback design

    OpenAIRE

    Collon, Carsten; Rudolph, Joachim

    2012-01-01

    Symmetries of nonlinear control systems in state representation are considered. To this end, a geometric approach to ordinary differential equations is advocated. Invariant feedback laws for systems with Lie symmetries, i.e. feedback laws that preserve the symmetry group of a considered plant, can be constructed based on invariants of the considered group action. Under minor technical assumptions suitable invariant tracking errors can be determined by following a normalization procedure. The ...

  6. Global exponential stability of recurrent neural networks for synthesizing linear feedback control systems via pole assignment.

    Science.gov (United States)

    Zhang, Yunong; Wang, Jun

    2002-01-01

    Global exponential stability is the most desirable stability property of recurrent neural networks. The paper presents new results for recurrent neural networks applied to online computation of feedback gains of linear time-invariant multivariable systems via pole assignment. The theoretical analysis focuses on the global exponential stability, convergence rates, and selection of design parameters. The theoretical results are further substantiated by simulation results conducted for synthesizing linear feedback control systems with different specifications and design requirements. PMID:18244461

  7. Design of CMS Beam Halo Monitor system

    CERN Document Server

    AUTHOR|(CDS)2078842

    2015-01-01

    A fast and directional monitoring system for the CMS experiment is designed to provide an online, bunch-by-bunch measurement of beam background induced by beam halo interactions, separately for each beam. The background detection is based on Cherenkov radiation produced in synthetic fused silica read out by a fast, UV sensitive photomultiplier tube. Twenty detector units per end will be azimuthally distributed around the rotating shielding of CMS, covering ~408 cm2 at 20.6m from the interaction point, at a radius of ~180 cm. The directional and fast response of the system allows the discrimination of the background particles from the dominant flux in the cavern induced by pp collision debris, produced within the 25 ns bunch spacing. A robust multi-layered shielding will enclose each detector unit to protect the photomultiplier tube from the magnetic field and to eliminate the occupancy from low energy particles. The design of the front-end units is validated by experimental results. An overview of the new sy...

  8. RF Beam control system for the Brookhaven relativistic heavy ion collider, RHIC

    International Nuclear Information System (INIS)

    The Relativistic Heavy Ion Collider, RHIC, is two counter-rotating rings with six interaction points. The RF Beam Control system for each ring will control two 28 MHz cavities for acceleration, and five 197 MHz cavities for preserving the 5 ns bunch length during 10 hour beam stores. Digital technology is used extensively in: Direct Digital Synthesis of rf signals and Digital Signal Processing for, the realization of state-variable feedback loops, real-time calculation of rf frequency, and bunch-by-bunch phase measurement of the 120 bunches. DSP technology enables programming the parameters of the feedback loops in order to obtain closed-loop dynamics that are independent of synchrotron frequency

  9. Switched steerable multiple beam antenna system

    Science.gov (United States)

    Iwasaki, Richard S.

    1988-09-01

    A steerable multibeam five element cross-feed cluster antenna system is described. The feed power is divided into five branches. Each branch includes a switching network comprised of a plurality of time delay elements each individually controlled by a respective electromagnetic latching switch. Frequency independent individual two-dimensional beam steering at intermediate (IF) scanning frequencies is thereby provided wherein discrete incremental time delays are introduced by the switching networks into each branch and the signals recombined thereafter to form each beam. The electromagnetic latched switching reduces power consumption and permits higher power switching and reciprocal coincident tranmsit and receive operation. Frequency independence due to incremental time delay switching permits coincident reciprocal operation and steering for transmit-receive signal paths carrying different transmit-receive frequencies. Diagonal quarter wave plates in the waveguides alter polarization from the circular to orthogonal linear to provide transmitter-receiver isolation.

  10. Is transverse feedback necessary for the SSC emittance preservation? (Vibration noise analysis and feedback parameters optimization)

    International Nuclear Information System (INIS)

    The paper considers the Superconducting Super Collider (SSC) site ground motion measurements as well as data from accelerators worldwide about noises that worsen beam performance. Unacceptably fast emittance growth due to these noises is predicted for the SSC. A transverse feedback system was found to be the only satisfactory alternative to prevent emittance decay. Optimization of the primary feedback parameters was done

  11. An interactive beam position monitor system simulator

    International Nuclear Information System (INIS)

    A system simulator has been implemented to aid the development of the RHIC position monitor system. Based on the LabVIEW software package by National Instruments, this simulator allows engineers and technicians to interactively explore the parameter space of a system during the design phase. Adjustable parameters are divided into three categories: beam, pickup, and electronics. The simulator uses these parameters in simple formulas to produce results in both time-domain and frequencydomain. During the prototyping phase, these simulated results can be compared to test data acquired with the same software package. The RHIC position monitor system is presented as an example, but the software is applicable to several other systems as well

  12. Multiplexed broadband beam steering system utilizing high speed MEMS mirrors

    OpenAIRE

    Knoernschild, Caleb; Kim, Changsoon; Lu, Felix P.; Kim, Jungsang

    2009-01-01

    We present a beam steering system based on micro-electromechanical systems technology that features high speed steering of multiple laser beams over a broad wavelength range. By utilizing high speed micromirrors with a broadband metallic coating, our system has the flexibility to simultaneously incorporate a wide range of wavelengths and multiple beams. We demonstrate reconfiguration of two independent beams at different wavelengths (780 and 635 nm) across a common 5x5 array with 4 us settlin...

  13. Vector perturbation based adaptive distributed precoding scheme with limited feedback for CoMP systems

    Directory of Open Access Journals (Sweden)

    Cuthbert Laurie

    2011-01-01

    Full Text Available Abstract A downlink adaptive distributed precoding scheme is proposed for coordinated multi-point (CoMP transmission systems. The serving base station (BS obtains the optimal precoding vector via user feedback. Meanwhile, the precoding vector of each coordinated BS is determined by adaptive gradient iteration according to the perturbation vector and the adjustment factor based on the vector perturbation method. In each transmission frame, the CoMP user feeds the precoding matrix index back to the serving BS, and feeds back the adjustment factor index to the coordinated BSs, which can reduce the uplink feedback overhead. The selected adjustment factor for each coordinated BS is obtained via the precoding vector of the coordinated BS used in the previous frame and the preferred precoding vector of the serving BS in this frame. The proposed scheme takes advantage of the spatial non-correlation and temporal correlation of the distributed MIMO channel. The design of the adjustment factor set is given and the channel feedback delay is considered. The system performance of the proposed scheme is verified with and without feedback delay respectively and the system feedback overhead is analyzed. Simulation results show that the proposed scheme has a good trade-off between system performance and the system control information overhead on feedback.

  14. Linear Feedback Analysis of Cardiovascular System using Seismocardiogram

    Directory of Open Access Journals (Sweden)

    Marcel Jiřina

    2005-01-01

    Full Text Available The paper deals with an analysis of relationship between heart rate described by a sequence of cardiac interbeat intervals and mechanical activity of heart represented by a sequence of systolic forces. Both the quantities were determined from seismocardiograms recorded from healthy subjects under two different experimental conditions. The method of the linear feedback baroreflex approach originally developed in [1], [2] and [3] was applied for the analysis. Different character of obtained results in comparison to those described in [1], [2] or [3], is explained by differences between frequency properties of the recorded sequences of the systolic forces and values of systolic blood pressure.

  15. Adaptive H∞ synchronization of chaotic systems via linear and nonlinear feedback control

    International Nuclear Information System (INIS)

    Adaptive H∞ synchronization of chaotic systems via linear and nonlinear feedback control is investigated. The chaotic systems are redesigned by using the generalized Hamiltonian systems and observer approach. Based on Lyapunov's stability theory, linear and nonlinear feedback control of adaptive H∞ synchronization is established in order to not only guarantee stable synchronization of both master and slave systems but also reduce the effect of external disturbance on an H∞-norm constraint. Adaptive H∞ synchronization of chaotic systems via three kinds of control is investigated with applications to Lorenz and Chen systems. Numerical simulations are also given to identify the effectiveness of the theoretical analysis. (general)

  16. PFC design via FRIT Approach for Adaptive Output Feedback Control of Discrete-time Systems

    Science.gov (United States)

    Mizumoto, Ikuro; Takagi, Taro; Fukui, Sota; Shah, Sirish L.

    This paper deals with a design problem of an adaptive output feedback control for discrete-time systems with a parallel feedforward compensator (PFC) which is designed for making the augmented controlled system ASPR. A PFC design scheme by a FRIT approach with only using an input/output experimental data set will be proposed for discrete-time systems in order to design an adaptive output feedback control system. Furthermore, the effectiveness of the proposed PFC design method will be confirmed through numerical simulations by designing adaptive control system with adaptive NN (Neural Network) for an uncertain discrete-time system.

  17. Large-scale outflows in luminous QSOs revisited: The impact of beam smearing on AGN feedback efficiencies

    CERN Document Server

    Husemann, B; Bennert, V N; Manieri, V; Woo, J -H; Kakkad, D

    2015-01-01

    Enormous observational effort has been made to constrain the energetics of AGN feedback by mapping the kinematics of the ionized gas on kpc scale with integral-field spectroscopy. Here, we investigate how the observed kinematics and inferred energetics are affected by beam smearing of a bright unresolved NLR due to seeing effects. We analysed optical IFU spectroscopy of a sample of twelve luminous unobscured QSOs (0.4

  18. Adaptive Neural Control of MIMO Nonstrict-Feedback Nonlinear Systems With Time Delay.

    Science.gov (United States)

    Zhao, Xudong; Yang, Haijiao; Karimi, Hamid Reza; Zhu, Yanzheng

    2016-06-01

    In this paper, an adaptive neural output-feedback tracking controller is designed for a class of multiple-input and multiple-output nonstrict-feedback nonlinear systems with time delay. The system coefficient and uncertain functions of our considered systems are both unknown. By employing neural networks to approximate the unknown function entries, and constructing a new input-driven filter, a backstepping design method of tracking controller is developed for the systems under consideration. The proposed controller can guarantee that all the signals in the closed-loop systems are ultimately bounded, and the time-varying target signal can be tracked within a small error as well. The main contributions of this paper lie in that the systems under consideration are more general, and an effective design procedure of output-feedback controller is developed for the considered systems, which is more applicable in practice. Simulation results demonstrate the efficiency of the proposed algorithm. PMID:26099151

  19. Sandia SCADA Program Real-Time Feedback Control of Power Systems; TOPICAL

    International Nuclear Information System (INIS)

    This report documents work supporting the Sandia National Laboratories initiative in Distributed Energy Resources (DERs) and Supervisory Control and Data Acquisition (SCADA) systems. One approach for real-time control of power generation assets using feedback control, Quantitative feedback theory (QFT), has recently been applied to voltage, frequency, and phase-control of power systems at Sandia. QFT provided a simple yet powerful philosophy for designing the control systems--allowing the designer to optimize the system by making design tradeoffs without getting lost in complex mathematics. The feedback systems were effective in reducing sensitivity to large and sudden changes in the power grid system. Voltage, frequency, and phase were accurately controlled, even with large disturbances to the power grid system

  20. Performance Analysis of Simple Channel Feedback Schemes for a Practical OFDMA System

    DEFF Research Database (Denmark)

    Pedersen, Klaus, I.; Kolding, Troels; Kovacs, Istvan;

    2009-01-01

    In this paper, we evaluate the tradeoff between the amount of uplink channel feedback information and the orthogonal frequency-division multiple access (OFDMA) downlink performance with opportunistic frequency-domain packet scheduling. Three candidate channel feedback schemes are investigated......, including practical aspects, such as the effects of terminal measurement errors, bandwidth measurement granularity, quantization, and uplink signaling delays. The performance is evaluated by means of system-level simulations with detailed modeling of various radio resource-management algorithms, etc. Our...... results show that the optimal tradeoff between the channel feedback and the downlink OFDMA system performance depends on the radio channel frequency coherence bandwidth. We conclude that the so-called average best-M scheme is the most attractive channel feedback solution, where only the average channel...

  1. Delayed feedback control of unstable steady states in fractional-order chaotic systems

    CERN Document Server

    Gjurchinovski, Aleksandar; Urumov, Viktor

    2010-01-01

    We study the possibility to stabilize unstable steady states in chaotic fractional-order dynamical systems by the time-delayed feedback method with both constant and time-varying delays. By performing a linear stability analysis in the constant delay case, we establish the parameter ranges for successful stabilization of unstable equilibria in the plane parametrizad by the feedback gain and the time delay. An insight into the control mechanism is gained by analyzing the characteristic equation of the controlled system, showing that the control scheme fails to control unstable equilibria having an odd number of positive real eigenvalues. It is shown numerically that delayed feedback control with a variable time-delay significantly enlarges the stability region of the steady states in comparison to the classical time-delayed feedback scheme with a constant delay.

  2. Dosimetric precision of an ion beam tracking system

    International Nuclear Information System (INIS)

    Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam positions and beam energy according to target motion. Motion compensation performance of the beam tracking system was assessed by measurements with radiographic films, a range telescope, a 3D array of 24 ionization chambers, and cell samples for biological dosimetry. Measurements were performed for stationary detectors and moving detectors using the beam tracking system. All detector systems showed comparable data for a moving setup when using beam tracking and the corresponding stationary setup. Within the target volume the mean relative differences of ionization chamber measurements were 0.3% (1.5% standard deviation, 3.7% maximum). Film responses demonstrated preserved lateral dose gradients. Measurements with the range telescope showed agreement of Bragg peak depth under motion induced range variations. Cell survival experiments showed a mean relative difference of -5% (-3%) between measurements and calculations within the target volume for beam tracking (stationary) measurements. The beam tracking system has been successfully integrated. Full functionality has been validated dosimetrically in experiments with several detector types including biological cell systems

  3. Dosimetric precision of an ion beam tracking system

    Directory of Open Access Journals (Sweden)

    Kraft Gerhard

    2010-06-01

    Full Text Available Abstract Background Scanned ion beam therapy of intra-fractionally moving tumors requires motion mitigation. GSI proposed beam tracking and performed several experimental studies to analyse the dosimetric precision of the system for scanned carbon beams. Methods A beam tracking system has been developed and integrated in the scanned carbon ion beam therapy unit at GSI. The system adapts pencil beam positions and beam energy according to target motion. Motion compensation performance of the beam tracking system was assessed by measurements with radiographic films, a range telescope, a 3D array of 24 ionization chambers, and cell samples for biological dosimetry. Measurements were performed for stationary detectors and moving detectors using the beam tracking system. Results All detector systems showed comparable data for a moving setup when using beam tracking and the corresponding stationary setup. Within the target volume the mean relative differences of ionization chamber measurements were 0.3% (1.5% standard deviation, 3.7% maximum. Film responses demonstrated preserved lateral dose gradients. Measurements with the range telescope showed agreement of Bragg peak depth under motion induced range variations. Cell survival experiments showed a mean relative difference of -5% (-3% between measurements and calculations within the target volume for beam tracking (stationary measurements. Conclusions The beam tracking system has been successfully integrated. Full functionality has been validated dosimetrically in experiments with several detector types including biological cell systems.

  4. Robust Feedback Controller for Exponential Stability of Nonlinear Systems with Mismatched Uncertainties

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The robust stabilization of nonlinear systems with mismatched uncertainties is investigated. Based on the stability of the nominal system, a new approach to synthesizing a class of continuous state feedback controllers for uncertain nonlinear dynamical systems is proposed. By such feedback controllers, the exponential stability of uncertain nonlinear dynamical systems can be guaranteed. The approach can give a clear insight to system analysis. An illustrative example is given to demonstrate the utilization of the approach developed. Simulation results show that the method presented is practical and effective.

  5. Electron beam accelerator energy control system

    International Nuclear Information System (INIS)

    A control system has been developed for the energy control of the electron beam accelerator using PLC. The accelerating voltage of 3 MV has been obtained by using parallel coupled voltage multiplier circuit. A autotransformer controlled variable 0-10 KV DC is fed to a tube based push pull oscillator to generate 120 Khz, 10 KV AC. Oscillator output voltage is stepped up to 0-300 KV/AC using a transformer. 0-300 KVAC is fed to the voltage multiplier column to generate the accelerating voltage at the dome 0-3 MV/DC. The control system has been designed to maintain the accelerator voltage same throughout the operation by adjusting the input voltage in close loop. Whenever there is any change in the output voltage either because of beam loading or arcing in the accelerator. The instantaneous accelerator voltage or energy is a direct proportional to 0-10 KVDC obtained from autotransformer. A PLC based control system with user settable energy level has been installed for 3 MeV, EB accelerator. The PLC takes the user defined energy value through a touch screen and compares it to the actual accelerating voltage (obtained using resistive divider). Depending upon the error the PLC generates the pulses to adjust the autotransformer to bring the actual voltage to the set value within the window of error (presently set to +/- 0.1%). (author)

  6. Non-Linear Beam Transport System for the LENS 7 MeV Proton Beam

    CERN Document Server

    Jones, William P; Derenchuk, Vladimir Peter; Rinckel, Thomas; Solberg, Keith

    2005-01-01

    A beam transport system has been designed to carry a high-intensity low-emittance proton beam from the exit of the RFQ-DTL acceleration system of the Indiana University Low Energy Neutron System (LENS)* to the neutron production target. The goal of the design was to provide a beam of uniform density over a 3cm by 3cm area at the target. Two octupole magnets** are employed in the beam line to provide the necessary beam phase space manipulations to achieve this goal. First order calculations were done using TRANSPORT and second order calculations have been performed using TURTLE. Second order simulations have been done using both a Gaussian beam distribution and a particle set generated by calculations of beam transport through the RFQ-DTL using PARMILA. Comparison of the design characteristics with initial measurements from the LENS commissioning process will be made.

  7. Bifurcation suppression of nonlinear systems via dynamic output feedback and its applications to rotating stall control

    Institute of Scientific and Technical Information of China (English)

    Pengnian CHEN; Huashu QIN; Shengwei MEI

    2005-01-01

    This paper deals with the problems of bifurcation suppression and bifurcation suppression with stability of nonlinear systems. Necessary conditions and sufficient conditions for bifurcation suppression via dynamic output feedback are presented;Sufficient conditions for bifurcation suppression with stability via dynamic output feedback are obtained. As an application, a dynamic compensator, which guarantees that the bifurcation point of rotating stall in axial flow compressors is stably suppressed, is constructed.

  8. Poisoned Feedback: The Impact of Malicious Users in Closed-Loop Multiuser MIMO Systems

    CERN Document Server

    Mukherjee, Amitav

    2010-01-01

    Accurate channel state information (CSI) at the transmitter is critical for maximizing spectral efficiency on the downlink of multi-antenna networks. In this work we analyze a novel form of physical layer attacks on such closed-loop wireless networks. Specifically, this paper considers the impact of deliberately inaccurate feedback by malicious users in a multiuser multicast system. Numerical results demonstrate the significant degradation in performance of closed-loop transmission schemes due to intentional feedback of false CSI by adversarial users.

  9. Effects of changes in climate on landscape and regional processes, and feedbacks to the climate system.

    Science.gov (United States)

    Callaghan, Terry V; Björn, Lars Olof; Chernov, Yuri; Chapin, Terry; Christensen, Torben R; Huntley, Brian; Ims, Rolf A; Johansson, Margareta; Jolly, Dyanna; Jonasson, Sven; Matveyeva, Nadya; Panikov, Nicolai; Oechel, Walter; Shaver, Gus; Schaphoff, Sibyll; Sitch, Stephen

    2004-11-01

    Biological and physical processes in the Arctic system operate at various temporal and spatial scales to impact large-scale feedbacks and interactions with the earth system. There are four main potential feedback mechanisms between the impacts of climate change on the Arctic and the global climate system: albedo, greenhouse gas emissions or uptake by ecosystems, greenhouse gas emissions from methane hydrates, and increased freshwater fluxes that could affect the thermohaline circulation. All these feedbacks are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Indications from a few, full annual measurements of CO2 fluxes are that currently the source areas exceed sink areas in geographical distribution. The little available information on CH4 sources indicates that emissions at the landscape level are of great importance for the total greenhouse balance of the circumpolar North. Energy and water balances of Arctic landscapes are also important feedback mechanisms in a changing climate. Increasing density and spatial expansion of vegetation will cause a lowering of the albedo and more energy to be absorbed on the ground. This effect is likely to exceed the negative feedback of increased C sequestration in greater primary productivity resulting from the displacements of areas of polar desert by tundra, and areas of tundra by forest. The degradation of permafrost has complex consequences for trace gas dynamics. In areas of discontinuous permafrost, warming, will lead to a complete loss of the permafrost. Depending on local hydrological conditions this may in turn lead to a wetting or drying of the environment with subsequent implications for greenhouse gas fluxes. Overall, the complex interactions between processes contributing to feedbacks, variability over time and space in these processes, and insufficient data have generated considerable uncertainties in estimating the net

  10. Decoupling service and feedback trust in a peer-to-peer reputation system

    OpenAIRE

    Swamynathan, Gayatri; Ben Y. Zhao; Almeroth, Kevin C.

    2005-01-01

    Reputation systems help peers decide whom to trust before undertaking a transaction. Conventional approaches to reputation-based trust modeling assume that peers reputed to provide trustworthy service are also likely to provide trustworthy feedback. By basing the credibility of a peer's feedback on its reputation as a transactor, these models become vulnerable to malicious nodes that provide good service to badmouth targeted nodes. We propose to decouple a peer's reputation as a service provi...

  11. Using student experience as a model for designing an automatic feedback system for short essays

    OpenAIRE

    Alden, Bethany; Van Labeke, Nicolas; Field, Debora; Pulman, Stephen; Richardson, John T. E.; Whitelock, Denise

    2014-01-01

    The SAFeSEA project (Supportive Automated Feedback for Short Essay Answers) aims to develop an automated feedback system to support university students as they write summative essays. Empirical studies carried out in the initial phase of the system’s development illuminated students’ approaches to and understandings of the essay-writing process. Findings from these studies suggested that, regardless of their experience of higher education, students consider essay-writing as: 1) a sequential s...

  12. Optimising Student Response Systems for Feedback and Higher-order Thinking in Mathematics

    OpenAIRE

    Lozanovski, Con; Tobin, Patrick

    2013-01-01

    Active teaching and learning technologies such as Student Response Systems have seen wide application in higher education over recent decades. This technology boasts a list of potential advantages such as enhancing the student experience and engagement in challenging subjects like mathematics. One of these advantages is immediate feedback for both the students and teaching staff. For students, this feedback is displayed during the lecture in the form of bar-charts allowing individuals to gaug...

  13. Robust design of feedback feed-forward iterative learning control based on 2D system theory for linear uncertain systems

    Science.gov (United States)

    Li, Zhifu; Hu, Yueming; Li, Di

    2016-08-01

    For a class of linear discrete-time uncertain systems, a feedback feed-forward iterative learning control (ILC) scheme is proposed, which is comprised of an iterative learning controller and two current iteration feedback controllers. The iterative learning controller is used to improve the performance along the iteration direction and the feedback controllers are used to improve the performance along the time direction. First of all, the uncertain feedback feed-forward ILC system is presented by an uncertain two-dimensional Roesser model system. Then, two robust control schemes are proposed. One can ensure that the feedback feed-forward ILC system is bounded-input bounded-output stable along time direction, and the other can ensure that the feedback feed-forward ILC system is asymptotically stable along time direction. Both schemes can guarantee the system is robust monotonically convergent along the iteration direction. Third, the robust convergent sufficient conditions are given, which contains a linear matrix inequality (LMI). Moreover, the LMI can be used to determine the gain matrix of the feedback feed-forward iterative learning controller. Finally, the simulation results are presented to demonstrate the effectiveness of the proposed schemes.

  14. Adaptive set-point tracking of the Lorenz chaotic system using non-linear feedback

    International Nuclear Information System (INIS)

    In this paper, an adaptive control method for set-point tracking of the Lorenz chaotic system by using non-linear feedback is proposed. The design procedure of the proposed controller is accomplished in two steps. At the first step, using Lyapunov's direct method, a non-linear state feedback is selected so that without any need to apply identification techniques, in despite of the uncertain parameters existence in the system state equations, the asymptotic stability of the general Lorenz system is guaranteed in a stochastic point of the manifold containing general system equilibrium points. At the second step, a linear state feedback with adaptive gain is added to the prior controller to eliminate the tracking error. In order to guarantee the system asymptotic stability at desired set-point, the indirect Lyapunov's method is used. Finally, to show the effectiveness of the proposed methodology, the simulation results of different experiments including system parameters changes and set-point variation are provided.

  15. Variable-delay feedback control of unstable steady states in retarded time-delayed systems

    CERN Document Server

    Gjurchinovski, Aleksandar; 10.1103/PhysRevE.81.016209

    2010-01-01

    We study the stability of unstable steady states in scalar retarded time-delayed systems subjected to a variable-delay feedback control. The important aspect of such a control problem is that time-delayed systems are already infinite-dimensional before the delayed feedback control is turned on. When the frequency of the modulation is large compared to the system's dynamics, the analytic approach consists of relating the stability properties of the resulting variable-delay system with those of an analogous distributed delay system. Otherwise, the stability domains are obtained by a numerical integration of the linearized variable-delay system. The analysis shows that the control domains are significantly larger than those in the usual time-delayed feedback control, and that the complexity of the domain structure depends on the form and the frequency of the delay modulation.

  16. A System for Monitoring and Tracking the LHC Beam Spot within the ATLAS High Level Trigger

    CERN Document Server

    Bartoldus, R; The ATLAS collaboration; Cogan, J; Salnikov, A; Strauss, E; Winklmeier, F

    2012-01-01

    The parameters of the beam spot produced by the LHC in the ATLAS interaction region are computed online using the ATLAS High Level Trigger (HLT) system. The high rate of triggered events is exploited to make precise measurements of the position, size and orientation of the luminous region in near real-time, as these parameters change significantly even during a single data-taking run. We present the challenges, solutions and results for the online determination, monitoring and beam spot feedback system in ATLAS. A specially designed algorithm, which uses tracks registered in the silicon detectors to reconstruct event vertices, is executed on the HLT processor farm of several thousand CPU cores. Monitoring histograms from all the cores are sampled and aggregated across the farm every 60 seconds. The reconstructed beam values are corrected for detector resolution effects, measured in situ from the separation of vertices whose tracks have been split into two collections. Furthermore, measurements for individual ...

  17. Mechatronic Development and Vision Feedback Control of a Nanorobotics Manipulation System inside SEM for Nanodevice Assembly

    Directory of Open Access Journals (Sweden)

    Zhan Yang

    2016-09-01

    Full Text Available Carbon nanotubes (CNT have been developed in recent decades for nanodevices such as nanoradios, nanogenerators, carbon nanotube field effect transistors (CNTFETs and so on, indicating that the application of CNTs for nanoscale electronics may play a key role in the development of nanotechnology. Nanorobotics manipulation systems are a promising method for nanodevice construction and assembly. For the purpose of constructing three-dimensional CNTFETs, a nanorobotics manipulation system with 16 DOFs was developed for nanomanipulation of nanometer-scale objects inside the specimen chamber of a scanning electron microscope (SEM. Nanorobotics manipulators are assembled into four units with four DOFs (X-Y-Z-θ individually. The rotational one is actuated by a picomotor. That means a manipulator has four DOFs including three linear motions in the X, Y, Z directions and a 360-degree rotational one (X-Y-Z-θ stage, θ is along the direction rotating with X or Y axis. Manipulators are actuated by picomotors with better than 30 nm linear resolution and <1 micro-rad rotary resolution. Four vertically installed AFM cantilevers (the axis of the cantilever tip is vertical to the axis of electronic beam of SEM served as the end-effectors to facilitate the real-time observation of the operations. A series of kinematic derivations of these four manipulators based on the Denavit-Hartenberg (D-H notation were established. The common working space of the end-effectors is 2.78 mm by 4.39 mm by 6 mm. The manipulation strategy and vision feedback control for multi-manipulators operating inside the SEM chamber were been discussed. Finally, application of the designed nanorobotics manipulation system by successfully testing of the pickup-and-place manipulation of an individual CNT onto four probes was described. The experimental results have shown that carbon nanotubes can be successfully picked up with this nanorobotics manipulation system.

  18. Conceptual Design of Neutral Beam Injection System for EAST

    Science.gov (United States)

    Hu, Chundong; NBI Team

    2012-06-01

    Neutral beam injection (NBI) system with two neutral beam injections will be constructed on the Experimental Advanced Superconducting Tokamak (EAST) in two stages for high power auxiliary plasmas heating and non-inductive current drive. Each NBI can deliver 2~4 MW beam power with 50~80 keV beam energy in 10~100 s pulse length. Each elements of the NBI system are presented in this contribution.

  19. Beam-beam effects under the influence of external noise

    OpenAIRE

    Ohmi, K.

    2014-01-01

    Fast external noise, which gives fluctuation into the beam orbit, is discussed in connection with beam-beam effects. Phase noise from crab cavities and detection devices (position monitor) and kicker noise from the bunch by bunch feedback system are the sources. Beam-beam collisions with fast orbit fluctuations with turn by turn or multi-turn correlations, cause emittance growth and luminosity degradation. We discuss the tolerance of the noise amplitude for LHC and HL-LHC.

  20. The fast beam interlock system for JET neutral injection

    International Nuclear Information System (INIS)

    The JET Neutral Beam Injection (NBI) system poses severe interlock problems with the possibility of unsafe conditions arising on a fast timescale. In order to cope with this the high-security Fast Beam Interlock System (FBIS) has been developed. It is used to turn off the beams in a failsafe manner when a condition arises which could damage the beam line or torus on a timescale too short to be dealt with by the JET Central Interlock and Safety System (CISS). FBIS interfaces signals from many JET safety systems and processes them to act directly on the Neutral Beam power supplies. The interfaces and the fail safety operation of FBIS are described. It is presently planned to upgrade the system to include a real-time comparison of the ion beam deflection magnet currents and the beam extraction voltage and a system which will compensate for the effects of the Tokamak stray fields on the NBI beamlines

  1. Chaotifying a stable linear controllable system by single input state feedback

    Institute of Scientific and Technical Information of China (English)

    Wu Zheng-Mao; Lu Jun-Guo; Xie Jian-Ying

    2007-01-01

    In this paper, an approach for chaotifying a stable controllable linear system via single input state-feedback is presented. The overflow function of the system states is designed as the feedback controller, which can make the fixed point of the closed-loop system to be a snap-back repeller, thereby yields chaotic dynamics. Based on the Marotto theorem, it proves theoretically that the closed-loop system is chaotic in the sense of Li and Yorke. Finally, the simulation results are used to illustrate the effectiveness of the proposed method.

  2. System identification from closed-loop data with known output feedback dynamics

    Science.gov (United States)

    Phan, Minh; Juang, Jer-Nan; Horta, Lucas G.; Longman, Richard W.

    1992-01-01

    This paper presents a procedure to identify the open loop systems when it is operating under closed loop conditions. First, closed loop excitation data are used to compute the system open loop and closed loop Markov parameters. The Markov parameters, which are the pulse response samples, are then used to compute a state space representation of the open loop system. Two closed loop configurations are considered in this paper. The closed loop system can have either a linear output feedback controller or a dynamic output feedback controller. Numerical examples are provided to illustrate the proposed closed loop identification method.

  3. A Novel Hybrid CQI Feedback Method For Throughput Improvement In 3GPP LTE Systems

    Directory of Open Access Journals (Sweden)

    Onkar Dandekar

    2013-10-01

    Full Text Available Frequency Selective Scheduling (FSS is a prominent characteristic in 3GPP LTE systems. Frequency scheduling depends on Channel Quality Indicator(CQI feedback report by mobile station. CQI being control information must use minimal bits maintaining the performance of system. This paper recommends a new CQI feedback method which uses existing schemes for improvement of performance of system. It throws light on enhancing throughput of Distributed Haar scheme with suitable usage of Best-M scheme. Proposed technique improves throughput while maintaining overhead reduction achieved by Haar compression schemes. Performance results indicate noticeable rise in throughput of the system as compared to Distributed Haar technique.

  4. Beam Tests of a Prototype Stripline Beam Position Monitoring System for the Drive Beam of the CLIC Two-beam Module at CTF3

    CERN Document Server

    Benot-Morell, Alfonso; Nappa, Jean-Marc; Vilalte, Sebastien; Wendt, Manfred

    2016-01-01

    In collaboration with LAPP and IFIC, two units of a prototype stripline Beam Position Monitor (BPM) for the CLIC Drive Beam (DB), and its associated readout electronics have been successfully installed and tested in the Two-Beam-Module (TBM) at the CLIC Test Facility 3 (CTF3) at CERN. This paper gives a short overview of the BPM system and presents the performance measured under different Drive Beam configurations.

  5. Integrated regional changes in arctic climate feedbacks: Implications for the global climate system

    Science.gov (United States)

    McGuire, A.D.; Chapin, F. S., III; Walsh, J.E.; Wirth, C.

    2006-01-01

    The Arctic is a key part of the global climate system because the net positive energy input to the tropics must ultimately be resolved through substantial energy losses in high-latitude regions. The Arctic influences the global climate system through both positive and negative feedbacks that involve physical, ecological, and human systems of the Arctic. The balance of evidence suggests that positive feedbacks to global warming will likely dominate in the Arctic during the next 50 to 100 years. However, the negative feedbacks associated with changing the freshwater balance of the Arctic Ocean might abruptly launch the planet into another glacial period on longer timescales. In light of uncertainties and the vulnerabilities of the climate system to responses in the Arctic, it is important that we improve our understanding of how integrated regional changes in the Arctic will likely influence the evolution of the global climate system. Copyright ?? 2006 by Annual Reviews. All rights reserved.

  6. Upgrade of plasma density feedback control system in HT-7 tokamak

    Institute of Scientific and Technical Information of China (English)

    ZHAO Da-Zheng; LUO Jia-Rong; LI Gang; JI Zhen-Shan; WANG Feng

    2004-01-01

    The HT-7 is a superconducting tokamak in China used to make researches on the controlled nuclear fusion as a national project for the fusion research. The plasma density feedback control subsystem is the one of the subsystems of the distributed control system in HT-7 tokamak (HT7DCS). The main function of the subsystem is to control the plasma density on real-time. For this reason, the real-time capability and good stability are the most significant factors, which will influence the control results. Since the former plasma density feedback control system (FPDFCS) based on Windows operation system could not fulfill such requirements well, a new subsystem has to be developed. The paper describes the upgrade of the plasma density feedback control system (UPDFCS), based on the dual operation system (Windows and Linux), in detail.

  7. Implementation of visualization system for beam service time in RIBF

    International Nuclear Information System (INIS)

    Beam availability is one important factor affecting research productivity of accelerator facilities. In RI Beam Factory (RIBF), the beam availability is defined simply as the ratio of actual beam service time to scheduled beam service time. The availability was previously estimated based on the down time of beam service recorded in our log-books of the paper medium. However, manual estimation of actual beam service time has limitation in its accuracy especially in case of hardware trouble. Hence, in order to realize labor-saving and accurate recording of down time, we have developed a visualization system that automatically records down time by using insertion status of Faraday cups. Implementation of the system has been completed and the system has been successfully operated in recent beam services performed in RIBF. (author)

  8. State derivative feedback in second-order linear systems: A comparative analysis of perturbed eigenvalues under coefficient variation

    Science.gov (United States)

    Araújo, José M.; Dórea, Carlos E. T.; Gonçalves, Luiz M. G.; Datta, Biswa N.

    2016-08-01

    This paper presents a comparative study of sensitivity to parameter variation in two feedback techniques applied in second-order linear systems: state feedback technique and the less conventional state derivative feedback technique. The former uses information on displacements and velocities whereas the latter uses velocities and accelerations. Several contributions on the problem of partial or full eigenvalue/eigenstructure assignment using the state feedback technique are presented in the literature. Recently, some interesting possibilities, such as solving the regularization problem in singular mass second-order systems, are approached using state derivative feedback. In this work, a general equivalence between state feedback and state derivative feedback is first established. Then, figures of merit on the resulting perturbed spectrum are proposed in order to assess the sensitivity of the closed-loop system to variations on the system matrices. Numerical examples are presented to support the obtained results.

  9. A 4.2 GS/sec. Synchronized Vertical Excitation System for SPS Studies - Steps Toward Wideband Feedback

    International Nuclear Information System (INIS)

    A 4.2 GS/sec. beam excitation system with accelerator synchronization and power stages is described. The system is capable of playing unique samples (32 samples/bunch) for 15,000 turns on selected bunch(es) in the SPS in syn- chronism with the injection and acceleration cycle. The purpose of the system is to excite internal modes of single-bunch vertical motion, and study the bunch dynamics in the presence of developing Electron cloud or TMCI effects. The system includes a synchronized master oscillator, SPS timing functions, an FPGA based arbitrary waveform generator, 4.2 GS/sec. D/A system and four 80W 20-1000 MHz amplifiers driving a tapered stripline pickup/kicker. A software GUI allows specification of various modulation signals, selection of bunches and turns to excite, while a remote control interface allows simple control/monitoring of the RF power stages located in the tunnel. The successful use of this system for SPS MD measurements in 2011 is a vital proof-of-principle for wideband feedback using similar functions to correct the beam motion.

  10. Development of fast beam-stop system using RF chopper

    International Nuclear Information System (INIS)

    To avoid heat damage and radioactivation by beam loss of the J-PARC accelerator, Machine Protection System (MPS) has been developed. Actually, high responsibility and high reliability have been achieved in J-PARC. Beam-stop method in addition to a way of RFQ OFF has been requested in order to avoid damage to the RFQ. Therefore, we have been developing a fast beam-stop system by using a RF chopper. The fast beam-stop system, including beam test, is described in this paper. (author)

  11. Multi User Feedback System Based On Performance and Appraisal Using Fuzzy Logic Base System- Design and Implementation

    Directory of Open Access Journals (Sweden)

    Ameet.D.Shah

    2014-03-01

    Full Text Available In Multi-user Feedback support system or 3600 Feedback, data on the performance of an individual are collected systematically from a number of stakeholders and are used for improving performance. The 3600 Feedback approach provides a consistent management philosophy meeting the criterion outlined previously. The 3600 feedback based appraisal is a comprehensive method where in the feedback about the employee comes from all the sources that come into contact with the employee on his/her job. The respondents for an employee can be her/his peers, managers, subordinates team members, customers, suppliers and vendors. Hence anyone who comes into contact with the employee, the 3600 appraisal has four components that include self-appraisal, superior’s appraisal, subordinate’s appraisal student’s appraisal and peer’s appraisal.

  12. The Saturne beam measurement system for orbit corrections and high and low intensity beam acceleration

    International Nuclear Information System (INIS)

    This paper summarizes the dipolar and multipolar correction system and the main beam diagnostics of Saturne II: wide-band RF electrostatic pick-up electrode for observation of bunches, beam position and tune measurement systems, special electrodes for observation of emittance blow-up when particles cross a resonance line. For low intensity beams, special electrodes and electronics have been developed. All this instrumentation is computer controlled

  13. ASSESSMENT OF THE VOLUNTEERED GEOGRAPHIC INFORMATION FEEDBACK SYSTEM FOR THE DUTCH TOPOGRAPHICAL KEY REGISTER

    Directory of Open Access Journals (Sweden)

    M. Grus

    2015-08-01

    Full Text Available Since Topographical Key Register has become an open data the amount of users increased enormously. The highest grow was in the private users group. The increasing number of users and their growing demand for high actuality of the topographic data sets motivates the Dutch Kadaster to innovate and improve the Topographical Key Register (BRT. One of the initiatives was to provide a voluntary geographical information project aiming at providing a user-friendly feedback system adjusted to all kinds of user groups. The feedback system is a compulsory element of the Topographical Key Register in the Netherlands. The Dutch Kadaster is obliged to deliver a feedback system and the key-users are obliged to use it. The aim of the feedback system is to improve the quality and stimulate the usage of the data. The results of the pilot shows that the user-friendly and open to everyone feedback system contributes enormously to improve the quality of the topographic dataset.

  14. Impact of Feedback Channel on Measured MIMO Systems and Its Lower Bound

    Institute of Scientific and Technical Information of China (English)

    ZHANGDuo; WEIGuo; ZHUJinkang

    2005-01-01

    A lower bound of the rate in feedback channel from a receiver to a transmitter is presented for measured Multiple-input-multiple-output (MIMO) systems based on the formulae of the open-loop and the closedloop MIMO capacity, under the assumptions of quasi-static block-fading MIMO channel, independent nondispersive fading between each transmit and receive antenna, sampling with the period equal to the reciprocal of the signal bandwidth at the receiver, and zero feedback delay. Through Monte Carlo simulations~ we numerically validate the existence of the lower bound and show numerical results of the bound for system design. Also, we conclude that, the Signal-to-noise ratio (SNR) impacts little on the lower bound of the feedback rate for low antenna numbers, a closed-loop system with a feedback rate less than the lower bound is worse than a open-loop system, and the lower bound remains small with respect to the increase of antenna number for low SNRs. Finally, it is shown that the lower bound of the feedback rate and the conclusions are applicable to practical closed-loop MIMO systems.

  15. Decentralised memory static output feedback control for the nonlinear time-delay similar interconnected systems

    Science.gov (United States)

    Ma, Yuechao; Jin, Shujie; Gu, Nannan

    2016-07-01

    In this paper, the problem of decentralised memory static output feedback control for a class of nonlinear time-delayed interconnected systems with similar structure is investigated, where both the linear and nonlinear state vectors involve time delay. The contributions of the paper include the following: (1) a new similar structure is presented via memory static output feedback; (2) by exploiting the structure of interconnected systems, the new integral inequalities, constrained Lyapunov equations and LMI method, the decentralised memory static output derivative feedback controllers with similar structure are designed, which is dependent of time delays, to stabilise the interconnected systems uniformly asymptotically; and (3) the stability domain is estimated. The conservatism of the results obtained is reduced by full using the system output information. Finally, the numerical examples are given to demonstrate the effectiveness of the results obtained in this paper.

  16. Improved beam spot measurements in the 2nd generation proton beam writing system

    International Nuclear Information System (INIS)

    Nanosized ion beams (especially proton and helium) play a pivotal role in the field of ion beam lithography and ion beam analysis. Proton beam writing has shown lithographic details down to the 20 nm level, limited by the proton beam spot size. Introducing a smaller spot size will allow smaller lithographic features. Smaller probe sizes, will also drastically improve the spatial resolution for ion beam analysis techniques. Among many other requirements, having an ideal resolution standard, used for beam focusing and a reliable focusing method, is an important pre-requisite for sub-10 nm beam spot focusing. In this paper we present the fabrication processes of a free-standing resolution standard with reduced side-wall projection and high side-wall verticality. The resulting grid is orthogonal (90.0° ± 0.1), has smooth edges with better than 6 nm side-wall projection. The new resolution standard has been used in focusing a 2 MeV H2+ beam in the 2nd generation PBW system at Center for Ion Beam Applications, NUS. The beam size has been characterized using on- and off-axis scanning transmission ion microscopy (STIM) and ion induced secondary electron detection, carried out with a newly installed micro channel plate electron detector. The latter has been shown to be a realistic alternative to STIM measurements, as the drawback of PIN diode detector damage is alleviated. With these improvements we show reproducible beam focusing down to 14 nm

  17. A new output feedback synchronization theorem for a class of chaotic systems with a scalar transmitted signal

    Institute of Scientific and Technical Information of China (English)

    Lu Jun-Guo

    2006-01-01

    This paper proposes a new, simple and yet applicable output feedback synchronization theorem for a large class of chaotic systems. We take a linear combination of drive system state variables as a scale-driving signal. It is proved that synchronization between the drive and the response systems can be obtained via a simple linear output error feedback control. The linear feedback gain is a function of a free parameter. The approach is illustrated using the Rossler hyperchaotic systems and Chua's chaotic oscillators.

  18. Output-back fuzzy logic systems and equivalence with feedback neural networks

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new idea, output-back fuzzy logic systems, is proposed. It is proved that output-back fuzzy logic systems must be equivalent to feedback neural networks. After the notion of generalized fuzzy logic systems is defined, which contains at least a typical fuzzy logic system and an output-back fuzzy logic system, one important conclusion is drawn that generalized fuzzy logic systems are almost equivalent to neural networks.

  19. AN M/M/1/N FEEDBACK QUEUING SYSTEM WITH REVERSE BALKING

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    2015-06-01

    Full Text Available In this paper we develop an M/M/1/N feedback queuing system with reverse balking. Reverse balking is a type of customer behavior according to which an arriving customer joins a system with high probability if he encounters large system size and vice-versa. This behavior of a customer can be observed in many businesses such as investment. Feedback customer in queuing literature refers to a customer who is unsatisfied with incomplete, partial or unsatisfactory service. We derive the steady-state solution of the model and obtain some important measures of performance. Sensitivity analysis of the model is also performed with respect to the parameters involved.

  20. Robust output feedback H-infinity control and filtering for uncertain linear systems

    CERN Document Server

    Chang, Xiao-Heng

    2014-01-01

    "Robust Output Feedback H-infinity Control and Filtering for Uncertain Linear Systems" discusses new and meaningful findings on robust output feedback H-infinity control and filtering for uncertain linear systems, presenting a number of useful and less conservative design results based on the linear matrix inequality (LMI) technique. Though primarily intended for graduate students in control and filtering, the book can also serve as a valuable reference work for researchers wishing to explore the area of robust H-infinity control and filtering of uncertain systems. Dr. Xiao-Heng Chang is a Professor at the College of Engineering, Bohai University, China.

  1. RF feedback for KEKB

    Energy Technology Data Exchange (ETDEWEB)

    Ezura, Eizi; Yoshimoto, Shin-ichi; Akai, Kazunori [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)

    1996-08-01

    This paper describes the present status of the RF feedback development for the KEK B-Factory (KEKB). A preliminary experiment concerning the RF feedback using a parallel comb-filter was performed through a choke-mode cavity and a klystron. The RF feedback has been tested using the beam of the TRISTAN Main Ring, and has proved to be effective in damping the beam instability. (author)

  2. Autogenic-Feedback Training Exercise (AFTE) Method and System

    Science.gov (United States)

    Cowings, Patricia S. (Inventor)

    1997-01-01

    The Autogenic-Feedback Training Exercise (AFTE) method of the present invention is a combined application of physiologic and perceptual training techniques. such as autogenic therapy and biofeedback. This combined therapy approach produces a methodology that is appreciably more effective than either of the individual techniques used separately. The AFTE method enables sufficient magnitude of control necessary to significantly reduce the behavioral and physiologic reactions to severe environmental stressors. It produces learned effects that are persistent over time and are resistant to extinction and it can be administered in a short period of time. The AFTE method may be used efficiently in several applications, among which are the following: to improve pilot and crew performance during emergency flying conditions; to train people to prevent the occurrence of nausea and vomiting associated with motion and sea sickness, or morning sickness in early pregnancy; as a training method for preventing or counteracting air-sickness symptoms in high-performance military aircraft; for use as a method for cardiovascular training, as well as for multiple other autonomic responses, which may contribute to the alleviation of Space Motion Sickness (SMS) in astronauts and cosmonauts; training people suffering from migraine or tension headaches to control peripheral blood flow and reduce forehead and/or trapezius muscle tension; training elderly people suffering from fecal incontinence to control their sphincter muscles; training cancer patients to reduce the nauseagenic effects of chemotherapy; and training patients with Chronic Intestinal Pseudo-obstruction (CIP).

  3. Robust Nonlinear Feedback Control of Aircraft Propulsion Systems

    Science.gov (United States)

    Garrard, William L.; Balas, Gary J.; Litt, Jonathan (Technical Monitor)

    2001-01-01

    This is the final report on the research performed under NASA Glen grant NASA/NAG-3-1975 concerning feedback control of the Pratt & Whitney (PW) STF 952, a twin spool, mixed flow, after burning turbofan engine. The research focussed on the design of linear and gain-scheduled, multivariable inner-loop controllers for the PW turbofan engine using H-infinity and linear, parameter-varying (LPV) control techniques. The nonlinear turbofan engine simulation was provided by PW within the NASA Rocket Engine Transient Simulator (ROCETS) simulation software environment. ROCETS was used to generate linearized models of the turbofan engine for control design and analysis as well as the simulation environment to evaluate the performance and robustness of the controllers. Comparison between the H-infinity, and LPV controllers are made with the baseline multivariable controller and developed by Pratt & Whitney engineers included in the ROCETS simulation. Simulation results indicate that H-infinity and LPV techniques effectively achieve desired response characteristics with minimal cross coupling between commanded values and are very robust to unmodeled dynamics and sensor noise.

  4. Beam extraction system in AIC-144 automatic isochronous cyclotron

    International Nuclear Information System (INIS)

    Project of beam extraction system in Cracow AIC-144 cyclotron is described. The problems of increase of beam emittance, and change of the magnetic field in the cyclotron chamber are discussed. Expected extraction coefficient of the beam is about 0.7. (S.B.)

  5. Beam characterisation of the KIRAMS electron microbeam system

    International Nuclear Information System (INIS)

    An electron microbeam system has been installed at the Korea Inst. of Radiological and Medical Sciences (KIRAMS) for use in radiation biology studies. The electron beam is produced from a commercial electron gun, and the beam size is defined by a 5 μm diameter pinhole. Beam energy can be varied in the range of 1-100 keV, covering a range of linear energy transfer from 0.4 to 12.1 keV μm-1. The micrometer-sized electron beam selectively irradiates cells cultured in a Mylar-bottomed dish. The positioning of target cells one by one onto the beam exit is automated, as is beam shooting. The electron beam entering the target cells has been calibrated using a Passivated Implanted Planar Silicon (PIPS) detector. This paper describes the KIRAMS microbeam cell irradiation system and its beam characteristics. (authors)

  6. Terrestrial biogeochemical feedbacks in the climate system: from past to future

    Energy Technology Data Exchange (ETDEWEB)

    Arneth, A.; Harrison, S. P.; Zaehle, S.; Tsigaridis, K; Menon, S; Bartlein, P.J.; Feichter, J; Korhola, A; Kulmala, M; O' Donnell, D; Schurgers, G; Sorvari, S; Vesala, T

    2010-01-05

    The terrestrial biosphere plays a major role in the regulation of atmospheric composition, and hence climate, through multiple interlinked biogeochemical cycles (BGC). Ice-core and other palaeoenvironmental records show a fast response of vegetation cover and exchanges with the atmosphere to past climate change, although the phasing of these responses reflects spatial patterning and complex interactions between individual biospheric feedbacks. Modern observations show a similar responsiveness of terrestrial biogeochemical cycles to anthropogenically-forced climate changes and air pollution, with equally complex feedbacks. For future conditions, although carbon cycle-climate interactions have been a major focus, other BGC feedbacks could be as important in modulating climate changes. The additional radiative forcing from terrestrial BGC feedbacks other than those conventionally attributed to the carbon cycle is in the range of 0.6 to 1.6 Wm{sup -2}; all taken together we estimate a possible maximum of around 3 Wm{sup -2} towards the end of the 21st century. There are large uncertainties associated with these estimates but, given that the majority of BGC feedbacks result in a positive forcing because of the fundamental link between metabolic stimulation and increasing temperature, improved quantification of these feedbacks and their incorporation in earth system models is necessary in order to develop coherent plans to manage ecosystems for climate mitigation.

  7. Biogeophysical feedbacks enhance Arctic terrestrial carbon sink in regional Earth system dynamics

    Directory of Open Access Journals (Sweden)

    W. Zhang

    2014-05-01

    Full Text Available Continued warming of the Arctic will likely accelerate terrestrial carbon (C cycling by increasing both uptake and release of C. There are still large uncertainties in modelling Arctic terrestrial ecosystems as a source or sink of C. Most modelling studies assessing or projecting the future fate of C exchange with the atmosphere are based an either stand-alone process-based models or coupled climate–C cycle general circulation models, in either case disregarding biogeophysical feedbacks of land surface changes to the atmosphere. To understand how biogeophysical feedbacks will impact on both climate and C budget over Arctic terrestrial ecosystems, we apply the regional Earth system model RCA-GUESS over the CORDEX-Arctic domain. The model is forced with lateral boundary conditions from an GCMs CMIP5 climate projection under the RCP 8.5 scenario. We perform two simulations with or without interactive vegetation dynamics respectively to assess the impacts of biogeophysical feedbacks. Both simulations indicate that Arctic terrestrial ecosystems will continue to sequester C with an increased uptake rate until 2060s–2070s, after which the C budget will return to a weak C sink as increased soil respiration and biomass burning outpaces increased net primary productivity. The additional C sinks arising from biogeophysical feedbacks are considerable, around 8.5 Gt C, accounting for 22% of the total C sinks, of which 83.5% are located in areas of Arctic tundra. Two opposing feedback mechanisms, mediated by albedo and evapotranspiration changes respectively, contribute to this response. Albedo feedback dominates over winter and spring season, amplifying the near-surface warming by up to 1.35 K in spring, while evapotranspiration feedback dominates over summer exerting the evaporative cooling by up to 0.81 K. Such feedbacks stimulate vegetation growth with an earlier onset of growing-season, leading to compositional changes in woody plants and vegetation

  8. The beam delivery modeling and error sources analysis of beam stabilization system for lithography

    Science.gov (United States)

    Wang, Jun; Huang, Lihua; Hou, Liying; He, Guojun; Ren, Bingqiang; Zeng, Aijun; Huang, Huijie

    2013-12-01

    Beam stabilization system is one of the most important units for lithography, which can accomplish displacement and pointing detection and control and includes beam measurement unit(BMU) and beam steering unit(BSU). Our group has set up a beam stabilization system and verified preliminarily beam stabilization algorithm of precise control beam position and angle. In the article, we establish beam delivery mathematic model and analyze the system inherent error. This shows that the reason why image rotation effect arises at the output plane of beam stabilization is the fast steering mirror (FSM) rotation of BSU in the process of beam stabilization. Two FSMs rotation around 45o axis of FSM make the most contribution to image rotation which rotates 1.414 mrad as two FSMs rotation angle difference changes 1 mrad. It is found that error sources include three key points: FSM accuracy; measurement noise and beam translation by passing through of beam splitters changing as the ambient temperature changing. FSM accuracy leads to the maximum 13.2μm displacement error and 24.49μrad angle error. Measurement inaccuracy as a result of 5μm measurement noise results in the maximum 0.126mm displacement error and 57.2μrad angle error. Beam translation errors can be negligible if temperature is unchanged. We have achieved beam stability of about 15.5μrad for angle and 28μm for displacement (both 1σ) after correcting 2mm initial displacement deviation and 5mrad initial angle deviation with regard to the system rebuilt due to practical requirements.

  9. An electrostatic beam rocking system on the Surrey nuclear microprobe

    International Nuclear Information System (INIS)

    The use of two sets of magnetic dipoles, producing opposite fields, to rock a focused MeV ion beam over the surface of a crystalline sample is now well established in several nuclear microprobe laboratories. Such a 'beam rocking' system allows ion channeling analysis from micron-size regions of the sample to be measured, with a beam displacement over the sample surface as small as a few microns, and no requirements for an automated goniometer. While magnetic beam rocking systems are ideal for many applications, they are limited in the speed at which the beam can be rocked in angle owing to hysteresis effects. This may also cause problems of non-reproducibility of the beam displacement on a micron scale. Also, heavier ions are more difficult to rock through a given angle using a magnetic beam rocking system, whereas an electrostatic beam rocking system gives a rocking angle which is independent of the ion mass. This paper describes the construction and uses of a fast electrostatic beam rocking system, which uses two sets of high voltage plates driven in opposition at high frequencies. Ion optics simulations are used to model the performance of the system. The optics of this beam rocking system, in which both sets of deflection plates are located before the quadruplet lens formation are discussed. The uses of this system to rapidly image the location of crystal planes and axes, and to carry out rapid channeling analysis are presented

  10. Particle beam injector system and method

    Science.gov (United States)

    Guethlein, Gary

    2013-06-18

    Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.

  11. Stability and Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback

    International Nuclear Information System (INIS)

    The stability and the Hopf bifurcation of a nonlinear electromechanical coupling system with time delay feedback are studied. By considering the energy in the air-gap field of the AC motor, the dynamical equation of the electromechanical coupling transmission system is deduced and a time delay feedback is introduced to control the dynamic behaviors of the system. The characteristic roots and the stable regions of time delay are determined by the direct method, and the relationship between the feedback gain and the length summation of stable regions is analyzed. Choosing the time delay as a bifurcation parameter, we find that the Hopf bifurcation occurs when the time delay passes through a critical value. A formula for determining the direction of the Hopf bifurcation and the stability of the bifurcating periodic solutions is given by using the normal form method and the center manifold theorem. Numerical simulations are also performed, which confirm the analytical results. (paper)

  12. Develop feedback system for intelligent dynamic resource allocation to improve application performance.

    Energy Technology Data Exchange (ETDEWEB)

    Gentile, Ann C.; Brandt, James M.; Tucker, Thomas (Open Grid Computing, Inc., Austin, TX); Thompson, David

    2011-09-01

    This report provides documentation for the completion of the Sandia Level II milestone 'Develop feedback system for intelligent dynamic resource allocation to improve application performance'. This milestone demonstrates the use of a scalable data collection analysis and feedback system that enables insight into how an application is utilizing the hardware resources of a high performance computing (HPC) platform in a lightweight fashion. Further we demonstrate utilizing the same mechanisms used for transporting data for remote analysis and visualization to provide low latency run-time feedback to applications. The ultimate goal of this body of work is performance optimization in the face of the ever increasing size and complexity of HPC systems.

  13. The Construction of Plasma Density Feedback Control System on J-TEXT Tokamak

    Science.gov (United States)

    Ke, Xin; Chen, Zhipeng; Ba, Weigang; Shu, Shuangbao; Gao, Li; Zhang, Ming; Zhuang, Ge

    2016-02-01

    The plasma density feedback control system (PDFCS) has been established on the Joint Texas Experimental Tokamak (J-TEXT) for meeting the need for an accurate plasma density in physical experiments. It consists of a density measurement subsystem, a feedback control subsystem and a gas puffing subsystem. According to the characteristic of the gas puffing system, a voltage amplitude control mode has been applied in the feedback control strategy, which is accomplished by the proportion, integral and differential (PID) controller. In this system, the quantity calibration of gas injection, adjusted responding to the change of the density signal, has been carried out. Some experimental results are shown and discussed. supported by the National Magnetic Confinement Fusion Science Program (Nos. 2014GB103001 and 2013GB106001) and National Natural Science Foundation of China (Nos. 11305070 and 11105028)

  14. An Automated Feedback System Based on Adaptive Testing: Extending the Model

    Directory of Open Access Journals (Sweden)

    Trevor Barker

    2010-06-01

    Full Text Available Abstract—The results of the recent national students survey (NSS revealed that a major problem in HE today is that of student feedback. Research carried out by members of the project team in the past has led to the development of an automated student feedback system for use with objective formative testing. This software relies on an ‘intelligent’ engine to determine the most appropriate individual feedback, based on test performance, relating not only to answers, but also to Bloom’s cognitive levels. The system also recommends additional materials and challenges, for each individual learner. Detailed evaluation with more than 500 students and 100 university staff have shown that the system is highly valued by learners and seen by staff as an important addition to the methods available. The software has been used on two modules so far over a two year period

  15. Output feedback stabilization for time-delay nonlinear interconnected systems using neural networks.

    Science.gov (United States)

    Hua, C; Guan, X

    2008-04-01

    In this paper, dynamic output feedback control problem is investigated for a class of nonlinear interconnected systems with time delays. Decentralized observer independent of the time delays is first designed. Then, we employ the bounds information of uncertain interconnections to construct the decentralized output feedback controller via backstepping design method. Based on Lyapunov stability theory, we show that the designed controller can render the closed-loop system asymptotically stable with the help of the changing supplying function idea. Furthermore, the corresponding decentralized control problem is considered under the case that the bounds of uncertain interconnections are not precisely known. By employing the neural network approximation theory, we construct the neural network output feedback controller with corresponding adaptive law. The resulting closed-loop system is stable in the sense of semiglobal boundedness. The observers and controllers constructed in this paper are independent of the time delays. Finally, simulations are done to verify the effectiveness of the theoretic results obtained. PMID:18390312

  16. Stabilizing equilibrium by linear feedback control for controlling chaos in Chen system

    Energy Technology Data Exchange (ETDEWEB)

    Costa, V A [Departamento de Ciencias Basicas, Facultad de IngenierIa (UNLP), La Plata (Argentina); Gonzalez, G A, E-mail: vacosta@ing.unlp.edu.ar, E-mail: ggonzal@fi.ub.ar [Departamento de Matematica, Facultad de Ingenieria (UBA), Buenos Aires (Argentina)

    2011-03-01

    Stabilization of a chaotic system in one of its unstable equilibrium points by applying small perturbations is studied. A two-stage control strategy based on linear feedback control is applied. Improvement of system performance is addressed by exploiting the ergodicity of the original dynamics and using Lyapunov stability results for control design. Extension to the not complete observability case is also analyzed.

  17. Stability investigations of the ASDEX feedback system with filters for reducing thyristor noise

    International Nuclear Information System (INIS)

    A computer program for analysing the absolute and relative stabilities of any complex system by the root-locus method was developed. It is used to reanalyse the present horizontal position feed-back control in the ASDEX tokamak and to select the optimum parameters for this system with RCL filters for reducing thyristor noise. (orig.)

  18. Benefits and Drawbacks of Computer-Based Assessment and Feedback Systems: Student and Educator Perspectives

    Science.gov (United States)

    Debuse, Justin C. W.; Lawley, Meredith

    2016-01-01

    Providing students with high quality feedback is important and can be achieved using computer-based systems. While student and educator perspectives of such systems have been investigated, a comprehensive multidisciplinary study has not yet been undertaken. This study examines student and educator perspectives of a computer-based assessment and…

  19. Nonlinear feedback synchronisation control between fractional-order and integer-order chaotic systems

    Institute of Scientific and Technical Information of China (English)

    Jia Li-Xin; Dai Hao; Hui Meng

    2010-01-01

    This paper focuses on the synchronisation between fractional-order and integer-order chaotic systems.Based on Lyapunov stability theory and numerical differentiation,a nonlinear feedback controller is obtained to achieve the synchronisation between fractional-order and integer-order chaotic systems.Numerical simulation results are presented to illustrate the effectiveness of this method.

  20. Design of multivariable feedback control systems via spectral assignment. [as applied to aircraft flight control

    Science.gov (United States)

    Liberty, S. R.; Mielke, R. R.; Tung, L. J.

    1981-01-01

    Applied research in the area of spectral assignment in multivariable systems is reported. A frequency domain technique for determining the set of all stabilizing controllers for a single feedback loop multivariable system is described. It is shown that decoupling and tracking are achievable using this procedure. The technique is illustrated with a simple example.

  1. Robust Passivity and Feedback Design for Nonlinear Stochastic Systems with Structural Uncertainty

    OpenAIRE

    Zhongwei Lin; Jizhen Liu; Yuguang Niu

    2013-01-01

    This paper discusses the robust passivity and global stabilization problems for a class of uncertain nonlinear stochastic systems with structural uncertainties. A robust version of stochastic Kalman-Yakubovitch-Popov (KYP) lemma is established, which sustains the robust passivity of the system. Moreover, a robust strongly minimum phase system is defined, based on which the uncertain nonlinear stochastic system can be feedback equivalent to a robust passive system. Following with the robust pa...

  2. Optimal control of nonlinear continuous-time systems in strict-feedback form.

    Science.gov (United States)

    Zargarzadeh, Hassan; Dierks, Travis; Jagannathan, Sarangapani

    2015-10-01

    This paper proposes a novel optimal tracking control scheme for nonlinear continuous-time systems in strict-feedback form with uncertain dynamics. The optimal tracking problem is transformed into an equivalent optimal regulation problem through a feedforward adaptive control input that is generated by modifying the standard backstepping technique. Subsequently, a neural network-based optimal control scheme is introduced to estimate the cost, or value function, over an infinite horizon for the resulting nonlinear continuous-time systems in affine form when the internal dynamics are unknown. The estimated cost function is then used to obtain the optimal feedback control input; therefore, the overall optimal control input for the nonlinear continuous-time system in strict-feedback form includes the feedforward plus the optimal feedback terms. It is shown that the estimated cost function minimizes the Hamilton-Jacobi-Bellman estimation error in a forward-in-time manner without using any value or policy iterations. Finally, optimal output feedback control is introduced through the design of a suitable observer. Lyapunov theory is utilized to show the overall stability of the proposed schemes without requiring an initial admissible controller. Simulation examples are provided to validate the theoretical results. PMID:26111400

  3. Toward design of the Collider Beam Collimation System

    International Nuclear Information System (INIS)

    A multi-component beam collimation system for the Superconducting Super Collider is described. System choice justification and design requirements are presented. System consists of targets, scrapers, and collimators with appropriate cooling and radiation shielding. Each component has an independent control for positioning and aligning with respect to the beam. Results of beam loss distribution, energy deposition calculations, and thermal analyses, as well as cost estimate, are presented

  4. Approaching system equilibrium with accurate or not accurate feedback information in a two-route system

    Science.gov (United States)

    Zhao, Xiao-mei; Xie, Dong-fan; Li, Qi

    2015-02-01

    With the development of intelligent transport system, advanced information feedback strategies have been developed to reduce traffic congestion and enhance the capacity. However, previous strategies provide accurate information to travelers and our simulation results show that accurate information brings negative effects, especially in delay case. Because travelers prefer to the best condition route with accurate information, and delayed information cannot reflect current traffic condition but past. Then travelers make wrong routing decisions, causing the decrease of the capacity and the increase of oscillations and the system deviating from the equilibrium. To avoid the negative effect, bounded rationality is taken into account by introducing a boundedly rational threshold BR. When difference between two routes is less than the BR, routes have equal probability to be chosen. The bounded rationality is helpful to improve the efficiency in terms of capacity, oscillation and the gap deviating from the system equilibrium.

  5. Bunch-by-bunch longitudinal feedback system for PEP-II

    International Nuclear Information System (INIS)

    This paper describes the implementation of the bunch-by-bunch longitudinal feedback system for the PEP-II B Factory. Bunch spacing down to 2 ns is achieved using 500 Megasamples per second A/D and D/A converters, and AT ampersand T 1610 Digital Signal Processors are integrated to run a downsampled feedback algorithm for each bunch in parallel. This general purpose programmable system, packaged in VXI and VME, is modular and scalable to offer portability to other accelerator rings. The control and monitoring hardware and software architecture have been developed to provide ease of operation as well as diagnostic tools for machine physics

  6. Evaluation of a bunch-by-bunch fast feedback system at ANKA

    Energy Technology Data Exchange (ETDEWEB)

    Marsching, Sebastian; Hiller, Nicole; Hofmann, Andre; Huttel, Erhard; Judin, Vitali; Kehrer, Benjamin; Klein, Marit; Mueller, Anke-Susanne; Smale, Nigel [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2011-07-01

    Multi-bunch instabilities are an important limiting factor in the operation of electron storage rings. Using modern bunch-by-bunch fast-feedback systems, these instabilities can be studied and partly damped, thus pushing accelerator performance beyond limits. At ANKA a bunch-by-bunch fast feedback system is currently evaluated for damping instabilities present during injection as well as during user operation. This talk presents the results of the ongoing work regarding the damping of these instabilities and the investigation of the corresponding multi-bunch effects.

  7. Design and Simulation of a Feedback Control System for a Steel Plate Storage

    Institute of Scientific and Technical Information of China (English)

    Torben; Feld; Holmgaard; Kristensen; Hans; Holm; Jesper; Hansen

    2002-01-01

    A discrete event heuristic feedback control system fo r a steel plate storage at Odense Steel Shipyard Ltd is developed and implemente d in a computer-based simulation model. The plant is subject to stochastic dist urbances. The control system is able to handle this stochastic behaviour bec ause of the feedback design. The present simulation results indicate that a bene fit in the range of 30%~40% is reachable by modifying the plant. Plant description The steel plate storage is located at Odense Steel ...

  8. Hopf bifurcation control for a coupled nonlinear relative rotation system with time-delay feedbacks

    Science.gov (United States)

    Liu, Shuang; Li, Xue; Tan, Shu-Xian; Li, Hai-Bin

    2014-10-01

    This paper investigates the Hopf bifurcations resulting from time delay in a coupled relative-rotation system with time-delay feedbacks. Firstly, considering external excitation, the dynamical equation of relative rotation nonlinear dynamical system with primary resonance and 1:1 internal resonance under time-delay feedbacks is deduced. Secondly, the averaging equation is obtained by the multiple scales method. The periodic solution in a closed form is presented by a perturbation approach. At last, numerical simulations confirm that time-delay theoretical analyses have influence on the Hopf bifurcation point and the stability of periodic solution.

  9. R-parametrization and its role in classification of linear multivariable feedback systems

    Science.gov (United States)

    Chen, Robert T. N.

    1988-01-01

    A classification of all the compensators that stabilize a given general plant in a linear, time-invariant multi-input, multi-output feedback system is developed. This classification, along with the associated necessary and sufficient conditions for stability of the feedback system, is achieved through the introduction of a new parameterization, referred to as R-Parameterization, which is a dual of the familiar Q-Parameterization. The classification is made to the stability conditions of the compensators and the plant by themselves; and necessary and sufficient conditions are based on the stability of Q and R themselves.

  10. Equilibrium of a two-route system with delayed information feedback strategies

    International Nuclear Information System (INIS)

    In intelligent transport system, some advanced information feedback strategies have been developed to reduce the oscillations and enhance the capacity on the road level. However, seldom strategies have considered the information delay and user equilibrium (UE) objective. Here, a derivative cost feedback strategy (DCFS) is proposed to reduce the influence of the delay, based on the UE principle. The simulation results show that in both no-delay and delay information cases, DCFS are the best and can make the system reaching the UE. Because DCFS can predict the trend of the travel cost.

  11. Time-Delayed Feedback Control in a Single-Mode Laser System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The effects of time-delayed feedback control in a single-mode laser system is investigated. Using the small time delay approximation, the analytic expression of the stationary probability distribution function of the laser field is obtaincd. The mean, normalized variance and skewness of the steady-state laser intensity are calculated. It is found that the time-delayed feedback control can suppress the intensity fluctuation of the laser system. The numerical simulations are in good agreement with the approximate analytic results.

  12. Recurrent fuzzy neural network by using feedback error learning approaches for LFC in interconnected power system

    International Nuclear Information System (INIS)

    In this study, a new adaptive controller based on modified feedback error learning (FEL) approaches is proposed for load frequency control (LFC) problem. The FEL strategy consists of intelligent and conventional controllers in feedforward and feedback paths, respectively. In this strategy, a conventional feedback controller (CFC), i.e. proportional, integral and derivative (PID) controller, is essential to guarantee global asymptotic stability of the overall system; and an intelligent feedforward controller (INFC) is adopted to learn the inverse of the controlled system. Therefore, when the INFC learns the inverse of controlled system, the tracking of reference signal is done properly. Generally, the CFC is designed at nominal operating conditions of the system and, therefore, fails to provide the best control performance as well as global stability over a wide range of changes in the operating conditions of the system. So, in this study a supervised controller (SC), a lookup table based controller, is addressed for tuning of the CFC. During abrupt changes of the power system parameters, the SC adjusts the PID parameters according to these operating conditions. Moreover, for improving the performance of overall system, a recurrent fuzzy neural network (RFNN) is adopted in INFC instead of the conventional neural network, which was used in past studies. The proposed FEL controller has been compared with the conventional feedback error learning controller (CFEL) and the PID controller through some performance indices

  13. Reliability Analysis of the new Link between the Beam Interlock System and the LHC Beam Dumping System Zuverlässigkeitsanalyse der neuen Verbindung zwischen dem Beam Interlock System und dem LHC Beam Dumping System

    CERN Document Server

    Vatansever, Volkan

    The nominal stored energy in each LHC beam is 360 MJ, surpassing the beam energy of other accelerators by orders of magnitude. This energy threatens to damage accelerator components in case of uncontrolled beam losses To avoid damage of accelerator equipment due to impacting beam, the controlled removal of the LHC beams from the collider rings towards the dump block must be guaranteed at all times. Therefore, the LHC Beam Dumping System was built according to high reliability standards. To further reduce the risk of incapability to dump the beams in case of correlated failures in the redundant system, a new direct link from the LHC Beam Interlock System to the Re-triggering Lines of the LHC Beam Dumping System will be implemented for the startup with beam in 2015. This link represents a diverse redundancy to the current implementation, which should neither significantly increase the risk for so-called Asynchronous Beam Dumps nor compromise machine availability. Therefore, a reliability analysis down to the co...

  14. Quantized Feedback Control Software Synthesis from System Level Formal Specifications

    CERN Document Server

    Mari, Federico; Salvo, Ivano; Tronci, Enrico

    2011-01-01

    Many Embedded Systems are indeed Software Based Control Systems (SBCSs), that is control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on Formal Model Based Design approaches for automatic synthesis of SBCS control software. We present an algorithm, along with a tool QKS implementing it, that from a formal model (as a Discrete Time Linear Hybrid System, DTLHS) of the controlled system (plant), implementation specifications (that is, number of bits in the Analog-to-Digital, AD, conversion) and System Level Formal Specifications (that is, safety and liveness requirements for the closed loop system) returns correct-by-construction control software that has a Worst Case Execution Time (WCET) linear in the number of AD bits and meets the given specifications. We show feasibility of our approach by presenting experimental results on using it to synthesize control software for a buck DC-DC converter, a widely used mixed-mode analog circuit.

  15. The N8 channel beam loss monitor system

    International Nuclear Information System (INIS)

    High intensity 70 GeV proton beam loss monitor system architecture in the area of single beam pass is described. The main system components choosing as detectors recording and controlling electronics are grounded on. There are list of the main system monitoring tasks and some experimental results. 12 refs.; 6 figs

  16. Feedback Techniques and Ecloud Instabilites - Design Estimates

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.D.; Mastorides, T.; Ndabashimiye, G.; Rivetta, C.; Winkle, D.Van; /SLAC; Byrd, J.; Vay, J-L; /LBL, Berkeley; Hofle, W.; Rumolo, G.; /CERN; Maria, R.De; /Brookhaven

    2009-05-18

    The SPS at high intensities exhibits transverse single-bunch instabilities with signatures consistent with an Ecloud driven instability. While the SPS has a coupled-bunch transverse feedback system, control of Ecloud-driven motion requires a much wider control bandwidth capable of sensing and controlling motion within each bunched beam. This paper draws beam dynamics data from the measurements and simulations of this SPS instability, and estimates system requirements for a feedback system with 2-4 GS/sec. sampling rates to damp Ecloud-driven transverse motion in the SPS at intensities desired for high-current LHC operation.

  17. Delayed feedback control of the Lorenz system: An analytical treatment at a subcritical Hopf bifurcation

    Science.gov (United States)

    Pyragas, V.; Pyragas, K.

    2006-03-01

    We develop an analytical approach for the delayed feedback control of the Lorenz system close to a subcritical Hopf bifurcation. The periodic orbits arising at this bifurcation have no torsion and cannot be stabilized by a conventional delayed feedback control technique. We utilize a modification based on an unstable delayed feedback controller. The analytical approach employs the center manifold theory and the near identity transformation. We derive the characteristic equation for the Floquet exponents of the controlled orbit in an analytical form and obtain simple expressions for the threshold of stability as well as for an optimal value of the control gain. The analytical results are supported by numerical analysis of the original system of nonlinear differential-difference equations.

  18. Time-delayed feedback control method for dynamical symmetry breaking in a periodically driven bistable system

    International Nuclear Information System (INIS)

    With the aim of formulating a method to control dynamic phase transitions in periodically driven bistable systems with reversal symmetry, a time-delayed feedback control method to stabilize an unstable periodic orbit in the broken symmetric regime is studied. In order to overcome a limitation of the conventional time-delayed feedback method, another extended scheme is proposed, and its improved ability with respect to stabilization is proved. Through the linear stability analysis of model controlled systems driven by sinusoidal fields, basic differences between the conventional and proposed methods are extracted. It is clarified that a few characteristics around the bifurcation point from the pitchfork critical branch to the Hopf branch and the turning point of the Hopf critical branch classify essential features of the stability diagram and concern restrictions for stabilization. Within the linear stability treatment, this paper estimates a safe choice and an effective range of feedback gains in the proposed method. (author)

  19. A weighted mean velocity feedback strategy in intelligent two-route traffic systems

    Institute of Scientific and Technical Information of China (English)

    Xiang Zheng-Tao; Xiong Li

    2013-01-01

    Information feedback strategies can influence the traffic efficiency of intelligent traffic systems greatly.Based on the more practical symmetrical two-route scenario with one entrance and one exit,an improved weighted mean velocity feedback strategy (WMVFS) is proposed,which is not sensitive to the precision of global position system (GPS) devices.The applicability of WMVFS to different weight factors,aggressive probabilities,densities of dynamic vehicles,and different two-route scenarios (symmetrical scenario and asymmetrical scenario with a speed limit bottleneck) is analyzed.Results show that WMVFS achieves the best performance compared with three other information feedback strategies when considering the traffic flux and stability.

  20. Fermilab Main Ring low level RF system modifications for focus free transition beam tests

    International Nuclear Information System (INIS)

    A novel idea for crossing transition energy has been proposed for study in the Fermilab Main Ring accelerator. The idea has been named focus free transition crossing and involves reducing the RF focusing force nearly to zero when the beam energy is near the transition energy by adding a third harmonic to the RF accelerating voltage, and then adjusting the accelerating phase angle to 90 degrees. The modification of the accelerating voltage wave form shape and phase are accomplished by accurate program control of the amplitude and phase of the 53 Mhz RF cavities and a recently installed 159 Mhz cavity. The studies also require interrupting the normal LLRF system beam energy feedback loops in favor of a new energy control loop near the transition energy. This paper describes the functions of the LLRF system electronics recently installed to facilitate this control, and initial operational experience with the system

  1. Research of a New 6-Dof Force Feedback Hand Controller System

    Directory of Open Access Journals (Sweden)

    Xin Gao

    2014-01-01

    Full Text Available The field of teleoperation with force telepresence has expanded its scope to include manipulation at different scales and in virtual worlds, and the key component of which is force feedback hand controller. This paper presents a novel force feedback hand controller system, including a 3-dof translational and 3-dof rotational hand controllers, respectively, to implement position and posture teleoperation of the robot end effector. The 3-dof translational hand controller adopts innovative three-axes decoupling structure based on the linear motor; the 3-dof rotational hand controller adopts serial mechanism based on three-axes intersecting at one point, improving its overall stiffness. Based on the kinematics, statics, and dynamics analyses for two platforms separately, the system applies big closed-loop force control method based on the zero force/torque, improving the feedback force/torque accuracy effectively. Experimental results show that self-developed 6-dof force feedback hand controller has good mechanical properties. The translational hand controller has the following advantages: simple kinematics solver, fast dynamic response, and better than 0.05 mm accuracy of three-axis end positioning, while the advantages of the rotational hand controller are wide turning space, larger than 1 Nm feedback, greater than 180 degrees of operating space of three axes, respectively, and high operation precision.

  2. Advantages of externally powered prosthesis with feedback system using pseudo-cineplasty

    Directory of Open Access Journals (Sweden)

    Seiji Nambu, MD;

    2014-11-01

    Full Text Available Externally powered upper-limb prostheses are difficult to use because of the lack of sensory feedback. Neuroprostheses have recently been developed for people with upper-limb amputation but are complicated, expensive, and still developing. We therefore designed a simple system by combining pseudo-cineplasty with extended physiological proprioception to provide sensory feedback to the body. We penetrated the palmaris longus tendon percutaneously with a metal ring, similar to that used in body piercing, in a nondisabled subject as a pseudo-cineplasty. The tendon and ring were connected to the system, and a sensory feedback experiment was performed. We investigated the ability of the user to determine the size of an object grasped by the prosthetic hand without visual information. The subject could distinguish between large and small objects with 100% accuracy and between small, medium, and large objects with 80% accuracy. In pseudo-cineplasty, control and sensory feedback are natural because the prosthetic hand is controlled by muscle contraction. Tension transmitted from the prosthetic hand is sensed via muscle spindles and skin sensors. This technique allows only partial sensory feedback but appears to offer several advantages over other human-machine interfaces.

  3. Instruction, Feedback and Biometrics: The User Interface for Fingerprint Authentication Systems

    Science.gov (United States)

    Riley, Chris; Johnson, Graham; McCracken, Heather; Al-Saffar, Ahmed

    Biometric authentication is the process of establishing an individual’s identity through measurable characteristics of their behaviour, anatomy or physiology. Biometric technologies, such as fingerprint systems, are increasingly being used in a diverse range of contexts from immigration control, to banking and personal computing. As is often the case with emerging technologies, the usability aspects of system design have received less attention than technical aspects. Fingerprint systems pose a number of challenges for users and past research has identified issues with correct finger placement, system feedback and instruction. This paper describes the development of an interface for fingerprint systems using an iterative, participative design approach. During this process, several different methods for the presentation of instruction and feedback were identified. The different types of instruction and feedback were tested in a study involving 82 participants. The results showed that feedback had a statistically significant effect on overall system performance, but instruction did not. The design recommendations emerging from this study, and the use of participatory design in this context, are discussed.

  4. BeamOptics : a Symbolic Platform for Modeling and the Solution of Beam Optics System

    International Nuclear Information System (INIS)

    BeamOptics [1] is a Mathematica-based computing platform devoted to the following objectives: (1) Structured representation and manipulation of particle beam optics systems with symbolic capabilities, (2) Analytical and numerical modeling of beam optics system behaviors, (3) Solution to specific beam optical or general accelerator system problems, in algebraic form in certain cases, through customized algorithms. Taking advantage of and conforming to the highly formal and self-contained structure of Mathematica, BeamOptics provides a unique platform for developing accelerator design and analysis programs. The feature of symbolic computation and the ability to manipulate the beam optics system at the programming language level enable the user to solve or optimize his system with considerably more efficiency, rigour and insight than can be easily achieved with passive modeling or numerical simulation methods. BeamOptics is developed with continuous evolution in mind. New features and algorithms from diverse sources can be incorporated without major modification, due to its formal and generic structure. In this report, a survey is given of the basic structure and methodology of BeamOptics, as well as a demonstration of some of its more specialized applications, and possible direction of evolution

  5. Differentiability of the Pritchard-Salamon systems with admissible state-feedback

    Institute of Scientific and Technical Information of China (English)

    YU Xin

    2005-01-01

    Many papers on a wide range of control problems for Pritchard-Salamon systems have appeared and many of its important mathematical and system theoretical properties have been revealed. This paper deals with the differentiability of the Pritchard-Salamon system with admissible state-feedback. Spectrum analysis showed that under definite condition, the unbounded perturbation semigroup of the Pritchard-Salamon system is eventually differentiable.

  6. Competitive intelligence system inorganizations - difficulties identified by experience feedback

    OpenAIRE

    Manel Guechtouli

    2014-01-01

    This paper is dealing with major issues on a competitive intelligence system. Our research is based on an inductive approach as we study the case of the competitive intelligence system of a big technological firm. Results identify three categories of factors that are widely discussed. Managerial recommendations are formulated.

  7. PLD-Based Reconfigurable Controllers for Feedback Systems

    CERN Document Server

    Gubarev, V F; Aksenov, N N; Palagin, A V; Opanasenko, V N; Sakharin, V G

    2001-01-01

    Recently, interest has grown for application of reconfigurable devices in robust and adaptive control systems. The main advantage of such devices is that its structure is not fixed and may be varied depending on the currently used control algorithm. In this paper a new PC-based reconfigurable microcontrollers (RMC) are offered for Experimental Physics control systems.

  8. Pathology tickler: an HL7 monitoring system to provide clinical feedback

    Science.gov (United States)

    Mongkolwat, Pattanasak; Davis, Elizabeth; Bhalodia, Pankit; Singh, Harinder; Channin, David S.

    2003-05-01

    The purpose of this project is to develop a software system to provide feedback to radiologists and other clinicians from interventional procedures in which they participate. Using Health Level Seven (HL7) traffic between the anatomy/pathology information system and other major information systems, we were able to develop a semi-automatic 'tickler' system that can notify clinicians of pathology results as well as the absence of pathology results after a specified time interval. By using this system, radiologists can get more rapid feedback concerning their interpretations and thereby learn to distinguish false positive from true positive cases. Potentially, fewer patients would fall through the follow-up cracks when using our system versus a paper-based method. The system demonstrates, among other things, how HL7 information can be a powerful tool at an institution when used for purposes for which it was not intentionally designed.

  9. High precision electron beam diagnostic system for high current long pulse beams

    International Nuclear Information System (INIS)

    As part of the effort to develop a multi-axis electron beam transport system using stripline kicker technology for DARHT II applications, it is necessary to precisely determine the position and extent of long high energy beams (6-40 MeV, 1-4 kA, 2 microseconds) for accurate position control. The kicker positioning system utilizes shot-to-shot adjustments for reduction of relatively slow (<20 MHz) motion of the beam centroid. The electron beams passing through the diagnostic systems have the potential for large halo effects that tend to corrupt measurements performed using capacitive pick-off probes. Likewise, transmission line traveling wave probes have problems with multi-bounce effects due to these longer pulse widths. Finally, the high energy densities experienced in these applications distort typical foil beam position measurements

  10. Adaptive, Nonlinear Model Predictive Control for Accelerator Feedback Control Systems

    International Nuclear Information System (INIS)

    Variations in systems dynamics and modeling uncertainty(due to unmodeled systems behavior and/or presence of disturbances),have posed significant challenges to the effective luminosity and orbit control in accelerators.Problems of similar nature occur in a wide variety of other applications from chemical processes to power plants to financial systems.Adaptive control has long been pursued as a possible solution,but difficulties with online model identification and robust implementation of the adaptive control algorithms has prevented their widespread application.In general developing and maintaining appropriate models is the key to the success of any deployed control solution.Meanwhile the performance of the control system is contingent on the responsiveness of the control algorithm to the inevitable deviations of the model from the actual system.This project uses neural networks to detect significant changes in system behavior,and develops an optimal model-predictive-based adaptive control algorithm that enables the robust implementation of an effective control strategy that is applicable in a wide range of applications.Simulation studies were conducted to clearly demonstrate the feasibility and benefits of implementing model predictive control technology in accelerator control problems.The requirements for an effective commercial product that can meet the challenge of optimal model-predictive-based adaptive control technology were developed.A prototype for the optimal model-predictive-based adaptive control algorithm was developed for a well-known nonlinear temperature control problem for gas-phase reactors that proved the feasibility of the proposed approach.This research enables a commercial party to leverage the knowledge gained through collaboration with a national laboratory to develop new system identification and optimal model-predictive-based adaptive control software to address current and future challenges in process industries,power systems

  11. Implementation of Feedback-Guided Voluntary Breath-Hold Gating for Cone Beam CT-Based Stereotactic Body Radiotherapy

    International Nuclear Information System (INIS)

    Purpose: To analyze tumor position reproducibility of feedback-guided voluntary deep inspiration breath-hold (FGBH) gating for cone beam computed tomography (CBCT)-based stereotactic body radiotherapy (SBRT). Methods and materials: Thirteen early-stage lung cancer patients eligible for SBRT with tumor motion of >1cm were evaluated for FGBH-gated treatment. Multiple FGBH CTs were acquired at simulation, and single FGBH CBCTs were also acquired prior to each treatment. Simulation CTs and treatment CBCTs were analyzed to quantify reproducibility of tumor positions during FGBH. Benefits of FGBH gating compared to treatment during free breathing, as well treatment with gating at exhalation, were examined for lung sparing, motion margins, and reproducibility of gross tumor volume (GTV) position relative to nonmoving anatomy. Results: FGBH increased total lung volumes by 1.5 times compared to free breathing, resulting in a proportional drop in total lung volume receiving 10 Gy or more. Intra- and inter-FGBH reproducibility of GTV centroid positions at simulation were 1.0 ± 0.5 mm, 1.3 ± 1.0 mm, and 0.6 ± 0.4 mm in the anterior-posterior (AP), superior-inferior (SI), and left-right lateral (LR) directions, respectively, compared to more than 1 cm of tumor motion at free breathing. During treatment, inter-FGBH reproducibility of the GTV centroid with respect to bony anatomy was 1.2 ± 0.7 mm, 1.5 ± 0.8 mm, and 1.0 ± 0.4 mm in the AP, SI, and LR directions. In addition, the quality of CBCTs was improved due to elimination of motion artifacts, making this technique attractive for poorly visualized tumors, even with small motion. Conclusions: The extent of tumor motion at normal respiration does not influence the reproducibility of the tumor position under breath hold conditions. FGBH-gated SBRT with CBCT can improve the reproducibility of GTV centroids, reduce required margins, and minimize dose to normal tissues in the treatment of mobile tumors.

  12. OUTPUT FEEDBACK CONTROL FOR MIMO NONLINEAR SYSTEMS WITH EXOGENOUS SIGNALS

    Institute of Scientific and Technical Information of China (English)

    Ying ZHOU; Yuqiang WU

    2006-01-01

    The paper addresses the global output tracking of a class of multi-input multi-output(MIMO) nonlinear systems affected by disturbances, which are generated by a known exosystem. An adaptive controller is designed based on the proposed observer and the backstepping approach to asymptotically track arbitrary reference signal and to guarantee the boundedness of all the signals in the closed loop system. Finally, the numerical simulation results illustrate the effectiveness of the proposed scheme.

  13. Beam shaping in high-power laser systems with using refractive beam shapers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2012-06-01

    Beam Shaping of the spatial (transverse) profile of laser beams is highly desirable by building optical systems of high-power lasers as well in various applications with these lasers. Pumping of the crystals of Ti:Sapphire lasers by the laser radiation with uniform (flattop) intensity profile improves performance of these ultrashort pulse high-power lasers in terms of achievable efficiency, peak-power and stability, output beam profile. Specifications of the solid-state lasers built according to MOPA configuration can be also improved when radiation of the master oscillator is homogenized and then is amplified by the power amplifier. Features of building these high power lasers require that a beam shaping solution should be capable to work with single mode and multimode beams, provide flattop and super-Gauss intensity distributions, the consistency and divergence of a beam after the intensity re-distribution should be conserved and low absorption provided. These specific conditions are perfectly fulfilled by the refractive field mapping beam shapers due to their unique features: almost lossless intensity profile transformation, low output divergence, high transmittance and flatness of output beam profile, extended depth of field, adaptability to real intensity profiles of TEM00 and multimode laser sources. Combining of the refractive field mapping beam shapers with other optical components, like beam-expanders, relay imaging lenses, anamorphic optics makes it possible to generate the laser spots of necessary shape, size and intensity distribution. There are plenty of applications of high-power lasers where beam shaping bring benefits: irradiating photocathode of Free Electron Lasers (FEL), material ablation, micromachining, annealing in display making techniques, cladding, heat treating and others. This paper will describe some design basics of refractive beam shapers of the field mapping type, with emphasis on the features important for building and applications

  14. Enhancement of mobility in an interacting colloidal system under feedback control

    Science.gov (United States)

    Gernert, Robert; Klapp, Sabine H. L.

    2015-08-01

    Feedback control schemes are a promising way to manipulate transport properties of driven colloidal suspensions. In the present article, we suggest a feedback scheme to enhance the collective transport of colloidal particles with repulsive interactions through a one-dimensional tilted washboard potential. The control is modeled by a harmonic confining potential, mimicking an optical "trap," with the center of this trap moving with the (instantaneous) mean particle position. Our theoretical analysis is based on the Smoluchowski equation combined with dynamical density functional theory for systems with hard-core or ultrasoft (Gaussian) interactions. For either type of interaction, we find that the feedback control can lead to an enhancement of the mobility by several orders of magnitude relative to the uncontrolled case. The largest effects occur for intermediate stiffness of the trap and large particle numbers. Moreover, in some regions of the parameter space the feedback control induces oscillations of the mean velocity. Finally, we show that the enhancement of mobility is robust against a small time delay in implementing the feedback control.

  15. Dynamic Output Feedback Control for Nonlinear Networked Control Systems with Random Packet Dropout and Random Delay

    Directory of Open Access Journals (Sweden)

    Shuiqing Yu

    2013-01-01

    Full Text Available This paper investigates the dynamic output feedback control for nonlinear networked control systems with both random packet dropout and random delay. Random packet dropout and random delay are modeled as two independent random variables. An observer-based dynamic output feedback controller is designed based upon the Lyapunov theory. The quantitative relationship of the dropout rate, transition probability matrix, and nonlinear level is derived by solving a set of linear matrix inequalities. Finally, an example is presented to illustrate the effectiveness of the proposed method.

  16. Opinion Analysis Using Domain Ontology for Implementing Natural Language Based Feedback System

    OpenAIRE

    Pratik K. Agrawal; Avinash J. Agrawal

    2014-01-01

    This paper proposes a natural language based feedback analysis system that extracts semantic relations from feedback data in order to map it with the domain ontology. After pre-processing a set of words or phrases are extracted from the input data. The data are analyzed semantically to interpret its meaning. This meaning is in an intermediate form which is then mapped to the terms defined in the ontology using similarity function. The opinion analysis of the semantic data is carried out for m...

  17. On the M/G/1 queueing system with multiclass customers and fixed feedback

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qi-zhi

    2008-01-01

    The M/G/1 queueing system with multiclass customer arrivals, fixed feedback, and first come first served policy is considered, where different classes of customers have different arrival rates, service-time distributions, and feedback numbers. The joint probability generation function of queue size of each class and the Laplace-Stieltjes transform of the total sojourn time of a customer in each class are presented, which extended the results obtained by Choi B D. The mean queue size of each class and mean total sojourn time of a customer in each class are obtained with this result. The results can be used in computer and communication networks for their performance analysis.

  18. Multivariable output feedback robust adaptive tracking control design for a class of delayed systems

    Science.gov (United States)

    Mirkin, Boris; Gutman, Per-Olof

    2015-02-01

    In this paper, we develop a model reference adaptive control scheme for a class of multi-input multi-output nonlinearly perturbed dynamic systems with unknown time-varying state delays which is also robust with respect to an external disturbance with unknown bounds. The output feedback adaptive control scheme uses feedback actions only, and thus does not require a direct measurement of the command or disturbance signals. A suitable Lyapunov-Krasovskii type functional is introduced to design the adaptation algorithms and to prove stability.

  19. Decentralized H∞ Control for Uncertain Interconnected Systems of Neutral Type via Dynamic Output Feedback

    Directory of Open Access Journals (Sweden)

    Heli Hu

    2014-01-01

    Full Text Available The design of the dynamic output feedback H∞ control for uncertain interconnected systems of neutral type is investigated. In the framework of Lyapunov stability theory, a mathematical technique dealing with the nonlinearity on certain matrix variables is developed to obtain the solvability conditions for the anticipated controller. Based on the corresponding LMIs, the anticipated gains for dynamic output feedback can be achieved by solving some algebraic equations. Also, the norm of the transfer function from the disturbance input to the controlled output is less than the given index. A numerical example and the simulation results are given to show the effectiveness of the proposed method.

  20. High-performance laser power feedback control system for cold atom physics

    Institute of Scientific and Technical Information of China (English)

    Bo Lu; Thibault Vogt; Xinxing Liu; Xiaoji Zhou; Xuzong Chen

    2011-01-01

    @@ A laser power feedback control system that features fast response,large-scale performance,low noise,and excellent stability is presented.Some essential points used for optimization are described.Primary optical lattice experiments are given as examples to show the performance of this system.With these performance characteristics,the power control system is useful for applications in cold atom physics and precision measurements.%A laser power feedback control system that features fast response, large-scale performance, low noise, and excellent stability is presented. Some essential points used for optimization are described. Primary optical lattice experiments are given as examples to show the performance of this system. With these performance characteristics, the power control system is useful for applications in cold atom physics and precision measurements.