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Sample records for active mode control

  1. Active control of multiple resistive wall modes

    International Nuclear Information System (INIS)

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitative agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc x Nc = 4 x 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc x Nc = 4 x 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7-8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback

  2. Active control of multiple resistive wall modes

    Science.gov (United States)

    Brunsell, P. R.; Yadikin, D.; Gregoratto, D.; Paccagnella, R.; Liu, Y. Q.; Bolzonella, T.; Cecconello, M.; Drake, J. R.; Kuldkepp, M.; Manduchi, G.; Marchiori, G.; Marrelli, L.; Martin, P.; Menmuir, S.; Ortolani, S.; Rachlew, E.; Spizzo, G.; Zanca, P.

    2005-12-01

    A two-dimensional array of saddle coils at Mc poloidal and Nc toroidal positions is used on the EXTRAP T2R reversed-field pinch (Brunsell P R et al 2001 Plasma Phys. Control. Fusion 43 1457) to study active control of resistive wall modes (RWMs). Spontaneous growth of several RWMs with poloidal mode number m = 1 and different toroidal mode number n is observed experimentally, in agreement with linear MHD modelling. The measured plasma response to a controlled coil field and the plasma response computed using the linear circular cylinder MHD model are in quantitive agreement. Feedback control introduces a linear coupling of modes with toroidal mode numbers n, n' that fulfil the condition |n - n'| = Nc. Pairs of coupled unstable RWMs are present in feedback experiments with an array of Mc × Nc = 4 × 16 coils. Using intelligent shell feedback, the coupled modes are generally not controlled even though the field is suppressed at the active coils. A better suppression of coupled modes may be achieved in the case of rotating modes by using the mode control feedback scheme with individually set complex gains. In feedback with a larger array of Mc × Nc = 4 × 32 coils, the coupling effect largely disappears, and with this array, the main internal RWMs n = -11, -10, +5, +6 are all simultaneously suppressed throughout the discharge (7 8 wall times). With feedback there is a two-fold extension of the pulse length, compared to discharges without feedback.

  3. SLIDING MODE CONTROL FOR ACTIVE AUTOMOBILE SUSPENSIONS

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    Nonlinear control methods are presented based on theory of sliding mode control (SMC) or variable structure control (VSC) for application to active automobile suspensions. Requirements of reducing manufacturing cost and energy consumption of the active suspension system may be satisfiedby reasonable design of the sliding surface and hydraulic servo system. Emphasis is placed on the study of the discrete sliding mode control method (DSMC) applicable for a new sort of speed on-off solenoid valves of anti-dust capability and low price. Robustness and effectiveness of the feedback linearized controller in typical road conditions are demonstrated by numerical results fora quarter-car suspension model.

  4. Broadband Radiation Modes: Estimation and Active Control

    NARCIS (Netherlands)

    Berkhoff, Arthur P.

    2002-01-01

    In this paper we give a formulation of the most efficiently radiating vibration patterns of a vibrating body, the radiation modes, in the time domain. The radiation modes can be used to arrive at efficient weighting schemes for an array of sensors in order to reduce the controller dimensionality. Be

  5. Researches on active structural acoustic control by radiation modes

    Institute of Scientific and Technical Information of China (English)

    MAO Qibo; JIANG Zhe

    2001-01-01

    Based on the radiation modes, an active control strategy is presented for sound radiation from elastic structures with an example of simply supported rectangular panel. The physical characteristics and mathematical meaning of the radiation modes are analyzed. The radiation efficiency of radiation mode falls off very rapidly with the increase of modes order at low frequency. A new control strategy is developed in which by canceling the adjoint coefficient of the first k radiation modes, the sound powers of the first k radiation modes is zero theoretically. The numerical calculation is made by using point force actuators as control forces.

  6. Resistive wall mode active control physics design for KSTAR

    Science.gov (United States)

    Park, Y. S.; Sabbagh, S. A.; Bak, J. G.; Bialek, J. M.; Berkery, J. W.; Lee, S. G.; Oh, Y. K.

    2014-01-01

    As KSTAR H-mode operation approaches the region where the resistive wall mode (RWM) can be unstable, an important issue for future long pulse, high beta plasma operation is to evaluate RWM active feedback control performance using a planned active/passive RWM stabilization system on the device. In particular, an optimal design of feedback sensors allows mode stabilization up to the highest achievable βN close to the ideal with-wall limit, βNwall, with reduced control power requirements. The computed ideal n = 1 mode structure from the DCON code has been input to the VALEN-3D code to calculate the projected performance of an active RWM control system in the KSTAR three-dimensional conducting structure device geometry. Control performance with the midplane locked mode detection sensors, off-midplane saddle loops, and magnetic pickup coils is examined. The midplane sensors measuring the radial component of the mode perturbation is found to be strongly affected by the wall eddy current. The off-axis saddle loops with proper compensation of the prompt applied field are computed to provide stabilization at βN up to 86% of βNwall but the low RWM amplitude computed in the off-axis regions near the sensors can produce a low signal-to-noise ratio. The required control power and bandwidth are also estimated with varied noise levels in the feedback sensors. Further improvements have been explored by examining a new RWM sensor design motivated by the off-midplane poloidal magnetic field sensors in NSTX. The new sensors mounted off of the copper passive stabilizer plates near the device midplane show a clear advantage in control performance corresponding to achieving 99% of βNwall without the need of compensation of the prompt field. The result shows a significant improvement of RWM feedback stabilization using the new sensor set which motivates a future feedback sensor upgrade.

  7. Bismuth Ferrite for Active Control of Surface Plasmon Polariton Modes

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose and investigate several layouts of m etal-insulator-metal waveguide with active core which can be utilized for dynamic switching in photonic integrated circuits. The active material, bismuth ferrite (BiFeO3), is sandwiched between metal plates and changes i ts refractive index through...

  8. Spectral Engineering with Coupled Microcavities: Active Control of Resonant Mode-Splitting

    CERN Document Server

    Souza, Mario C M M; Barea, Luis A M; von Zuben, Antonio A G; Wiederhecker, Gustavo S; Frateschi, Newton C

    2015-01-01

    Optical mode-splitting is an efficient tool to shape and fine-tune the spectral response of resonant nanophotonic devices. The active control of mode-splitting, however, is either small or accompanied by undesired resonance shifts, often much larger than the resonance-splitting. We report a control mechanism that enables reconfigurable and widely tunable mode-splitting while efficiently mitigating undesired resonance shifts. This is achieved by actively controlling the excitation of counter-traveling modes in coupled resonators. The transition from a large splitting (80 GHz) to a single-notch resonance is demonstrated using low power microheaters (35 mW). We show that the spurious resonance-shift in our device is only limited by thermal crosstalk and resonance-shift-free splitting control may be achieved.

  9. Active Disturbance Rejection with Sliding Mode Control Based Course and Path Following for Underactuated Ships

    Directory of Open Access Journals (Sweden)

    Ronghui Li

    2013-01-01

    Full Text Available The compound control of active-disturbance-rejection control (ADRC with sliding mode is proposed to improve the performance of the closed-loop system and deal with the constraint condition problem of a surface ship. The advantages of ADRC with sliding mode were verified by ship course control simulations. Meanwhile, to solve the path-following problem of underactuated surface ships with uncertainties of internal dynamic and external disturbances, the ADRC controller with sliding mode is introduced to steer the ship to follow the desired path. In order to overcome the cross-track error caused by wind and current, drift angle is compensated in the controller by designing a coordinate transformation equation. Simulations were performed on a nonlinear kinematics model of a training ship to validate the stability and excellent robustness of the proposed path-following controller.

  10. Design and control of a prosthetic leg for above-knee amputees operated in semi-active and active modes

    Science.gov (United States)

    Park, Jinhyuk; Yoon, Gun-Ha; Kang, Je-Won; Choi, Seung-Bok

    2016-08-01

    This paper proposes a new prosthesis operated in two different modes; the semi-active and active modes. The semi-active mode is achieved from a flow mode magneto-rheological (MR) damper, while the active mode is obtained from an electronically commutated (EC) motor. The knee joint part of the above knee prosthesis is equipped with the MR damper and EC motor. The MR damper generates reaction force by controlling the field-dependent yield stress of the MR fluid, while the EC motor actively controls the knee joint angle during gait cycle. In this work, the MR damper is designed as a two-end type flow mode mechanism without air chamber for compact size. On other hand, in order to predict desired knee joint angle to be controlled by EC motor, a polynomial prediction function using a statistical method is used. A nonlinear proportional-derivative controller integrated with the computed torque method is then designed and applied to both MR damper and EC motor to control the knee joint angle. It is demonstrated that the desired knee joint angle is well achieved in different walking velocities on the ground ground.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Le, Thanh Danh; Ahn, Kyoung Kwan [Univ. of Ulsan, Ulsan (Korea, Republic of)

    2012-12-15

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

  13. A Multi-Mode Blade Damping Control using Shunted Piezoelectric Transducers with Active Feedback Structure

    Science.gov (United States)

    Choi, Benjamin; Morrison, Carlos; Min, James

    2009-01-01

    The Structural Dynamics and. Mechanics branch (RXS) is developing smart adaptive structures to improve fan blade damping at resonances using piezoelectric (PE) transducers. In this presentation, only one shunted PE transducer was used to demonstrate active control of multi-mode blade resonance damping on a titanium alloy (Ti-6A1-4V) flat plate model, regardless of bending, torsion, and 2-stripe modes. This work would have a significant impact on the conventional passive shunt damping world because the standard feedback control design tools can now be used to design and implement electric shunt for vibration control. In other words, the passive shunt circuit components using massive inductors and. resistors for multi-mode resonance control can be replaced with digital codes. Furthermore, this active approach with multi patches can simultaneously control several modes in the engine operating range. Dr. Benjamin Choi presented the analytical and experimental results from this work at the Propulsion-Safety and. Affordable Readiness (P-SAR) Conference in March, 2009.

  14. Stability of the Tilt Modes of an Actively Controlled Flywheel Analyzed

    Science.gov (United States)

    Brown, Gerald V.; Kascak, Albert F.

    1999-01-01

    Applications of strongly gyroscopic rotors are becoming important, including flywheels for terrestrial and space energy storage and various attitude control devices for spacecraft. Some of these applications, especially the higher speed ones for energy storage, will have actively controlled magnetic bearings. These bearings will be required where speeds are too high for conventional bearings, where adequate lubrication is undesirable or impossible, or where bearing losses must be minimized for efficient energy storage. Flywheel rotors are highly gyroscopic, and above some speed that depends on the bandwidth of the feedback system, they always become unstable in an actively controlled magnetic bearing system. To assess ways to prevent instability until speeds well above the desired operating range, researchers at the NASA Lewis Research Center used a commercial controls code to calculate the eigenvalues of the tilt modes of a rigid gyroscopic rotor supported by active magnetic bearings. The real part of the eigenvalue is the negative of the damping of the mode, and the imaginary part is approximately equal to the mode s frequency.

  15. Adaptive Neural-Sliding Mode Control of Active Suspension System for Camera Stabilization

    Directory of Open Access Journals (Sweden)

    Feng Zhao

    2015-01-01

    Full Text Available The camera always suffers from image instability on the moving vehicle due to the unintentional vibrations caused by road roughness. This paper presents a novel adaptive neural network based on sliding mode control strategy to stabilize the image captured area of the camera. The purpose is to suppress vertical displacement of sprung mass with the application of active suspension system. Since the active suspension system has nonlinear and time varying characteristics, adaptive neural network (ANN is proposed to make the controller robustness against systematic uncertainties, which release the model-based requirement of the sliding model control, and the weighting matrix is adjusted online according to Lyapunov function. The control system consists of two loops. The outer loop is a position controller designed with sliding mode strategy, while the PID controller in the inner loop is to track the desired force. The closed loop stability and asymptotic convergence performance can be guaranteed on the basis of the Lyapunov stability theory. Finally, the simulation results show that the employed controller effectively suppresses the vibration of the camera and enhances the stabilization of the entire camera, where different excitations are considered to validate the system performance.

  16. Semi-active Sliding Mode Control of Vehicle Suspension with Magneto-rheological Damper

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hailong; WANG Enrong; ZHANG Ning; MIN Fuhong; SUBASH Rakheja; SU Chunyi

    2015-01-01

    The vehicle semi-active suspension with magneto-rheological damper(MRD) has been a hot topic since this decade, in which the robust control synthesis considering load variation is a challenging task. In this paper, a new semi-active controller based upon the inverse model and sliding mode control (SMC) strategies is proposed for the quarter-vehicle suspension with the magneto-rheological (MR) damper, wherein an ideal skyhook suspension is employed as the control reference model and the vehicle sprung mass is considered as an uncertain parameter. According to the asymptotical stability of SMC, the dynamic errors between the plant and reference systems are used to derive the control damping force acquired by the MR quarter-vehicle suspension system. The proposed modified Bouc-wen hysteretic force-velocity (F-v) model and its inverse model of MR damper, as well as the proposed continuous modulation (CM) filtering algorithm without phase shift are employed to convert the control damping force into the direct drive current of the MR damper. Moreover, the proposed semi-active sliding mode controller (SSMC)-based MR quarter-vehicle suspension is systematically evaluated through comparing the time and frequency domain responses of the sprung and unsprung mass displacement accelerations, suspension travel and the tire dynamic force with those of the passive quarter-vehicle suspension, under three kinds of varied amplitude harmonic, rounded pulse and real-road measured random excitations. The evaluation results illustrate that the proposed SSMC can greatly suppress the vehicle suspension vibration due to uncertainty of the load, and thus improve the ride comfort and handling safety. The study establishes a solid theoretical foundation as the universal control scheme for the adaptive semi-active control of the MR full-vehicle suspension decoupled into four MR quarter-vehicle sub-suspension systems.

  17. Active control of edge localized modes with a low n perturbation fields in the JET tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Y., E-mail: y.liang@fz-juelich.d [Association EURATOM-FZJ, Forschungszentrum Juelich GmbH, Institute of Energy Research IEF-4: Plasma Physics, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany); Jachmich, S. [Association EURATOM-Belgian State, Koninklijke Militaire School - Ecole Royale Militaire, B-1000 Brussels (Belgium); Koslowski, H.R. [Association EURATOM-FZJ, Forschungszentrum Juelich GmbH, Institute of Energy Research IEF-4: Plasma Physics, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany); Nardon, E. [EURATOM-UKAEA Fusion Association, Culham Science Centre, OX14 3DB Abingdon, OXON (United Kingdom); Alfier, A. [Associazione EURATOM-ENEA sulla Fusione, Consorzio RFX Padova (Italy); Baranov, Y. [EURATOM-UKAEA Fusion Association, Culham Science Centre, OX14 3DB Abingdon, OXON (United Kingdom); De La Luna, E. [Asociacion EURATOM-CIEMAT, Avenida Complutense 22, E-28040 Madrid (Spain); Vries, P. de [EURATOM-UKAEA Fusion Association, Culham Science Centre, OX14 3DB Abingdon, OXON (United Kingdom); Eich, T. [Association EURATOM-Max-Planck-Institut fuer Plasmaphysik, D-85748 Garching (Germany); Esser, H.G.; Harting, D. [Association EURATOM-FZJ, Forschungszentrum Juelich GmbH, Inst. of Energy Research IEF-4: Plasma Physics, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany); Kiptily, V. [EURATOM-UKAEA Fusion Association, Culham Science Centre, OX14 3DB Abingdon, OXON (United Kingdom); Kreter, A. [Association EURATOM-FZJ, Forschungszentrum Juelich GmbH, Inst. of Energy Research IEF-4: Plasma Physics, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany); Gerasimov, S.; Gryaznevich, M.P.; Howell, D. [EURATOM-UKAEA Fusion Association, Culham Science Centre, OX14 3DB Abingdon, OXON (United Kingdom); Sergienko, G. [Association EURATOM-FZJ, Forschungszentrum Juelich GmbH, Inst. of Energy Research IEF-4: Plasma Physics, Partner in the Trilateral Euregio Cluster, 52425 Juelich (Germany)

    2009-06-15

    Active control of edge localized modes (ELMs) by using static external magnetic perturbation fields with low toroidal mode number, n, has been demonstrated for both, ITER baseline (q{sub 95}approx3) and high beta advanced tokamak scenarios at the JET tokamak. During the application of the low n field the ELM frequency increased by a factor up to approx4-5. Reduction in carbon erosion and ELM peak heat fluxes on the divertor target by roughly the same factor as the increase of the ELM frequency has been observed. The frequency of the mitigated ELMs using a low n field is found to increase proportional to the total input heating power. Compensation of the density pump-out effect observed when the external low n field is applied has been achieved by gas fueling in low triangularity plasmas.

  18. Effect Analysis of Fans Activating Time on Smoke Control Mode for Road Tunnel Fire

    Directory of Open Access Journals (Sweden)

    Xin Han

    2013-04-01

    Full Text Available With the development of economy, more and more road tunnels have been built. Due to the relatively isolated environment of the tunnel, fire protection is the most important factor for the safe management of tunnel operation. During the fire process, many people are killed by the fire smoke. As for preventive measures of road tunnel fire, smoke exhaust system is the most effective way to control the spread of fire smoke. Based on full size tunnel fire test and simulation analysis, this study carries out effect analysis of fans activating time on smoke control mode for road tunnel fire. The corresponding results are useful to establish fire control strategy and personnel evacuation plan for tunnel management system.

  19. Application of output feedback sliding mode control to active flutter suppression of two-dimensional airfoil

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effectiveness of the sliding mode control(SMC) method for active flutter suppression(AFS) and the issues concerning control system discretization and control input constraints were studied using a typical two-dimensional airfoil.The airfoil has a trailing-edge flap for flutter control.The aeroelastic system involves a two-degrees-of-freedom motion(pitch and plunge),and the equations were constructed by utilizing quasi-steady aerodynamic forces.The control system,designed by the output feedback SMC method,was incorporated to suppress the pitch-plunge flutter.Meanwhile,the system discretization and the flap deflection constraints were implemented.Then,a classical Runge-Kutta(RK) algorithm was utilized for numerical calculations.The results indicated that the close-loop system with the SMC system could be stable at a speed above the flutter boundary.However,when the flap deflection limits are reached,the close-loop system with the simple discretized control system loses control.Furthermore,control compensation developed by theoretical analysis was proposed to make the system stable again.The parameter perturbations and the time delay effects were also discussed in this paper.

  20. State observer-based sliding mode control for semi-active hydro-pneumatic suspension

    Science.gov (United States)

    Ren, Hongbin; Chen, Sizhong; Zhao, Yuzhuang; Liu, Gang; Yang, Lin

    2016-02-01

    This paper proposes an improved virtual reference model for semi-active suspension to coordinate the vehicle ride comfort and handling stability. The reference model combines the virtues of sky-hook with ground-hook control logic, and the hybrid coefficient is tuned according to the longitudinal and lateral acceleration so as to improve the vehicle stability especially in high-speed condition. Suspension state observer based on unscented Kalman filter is designed. A sliding mode controller (SMC) is developed to track the states of the reference model. The stability of the SMC strategy is proven by means of Lyapunov function taking into account the nonlinear damper characteristics and sprung mass variation of the vehicle. Finally, the performance of the controller is demonstrated under three typical working conditions: the random road excitation, speed bump road and sharp acceleration and braking. The simulation results indicated that, compared with the traditional passive suspension, the proposed control algorithm can offer a better coordination between vehicle ride comfort and handling stability. This approach provides a viable alternative to costlier active suspension control systems for commercial vehicles.

  1. Smooth Sliding Mode Control for Vehicle Rollover Prevention Using Active Antiroll Suspension

    Directory of Open Access Journals (Sweden)

    Duanfeng Chu

    2015-01-01

    Full Text Available The rollover accidents induced by severe maneuvers are very dangerous and mostly happen to vehicles with elevated center of gravity, such as heavy-duty trucks and pickup trucks. Unfortunately, it is hard for drivers of those vehicles to predict and prevent the trend of the maneuver-induced (untripped rollover ahead of time. In this study, a lateral load transfer ratio which reflects the load distribution of left and right tires is used to indicate the rollover criticality. An antiroll controller is designed with smooth sliding mode control technique for vehicles, in which an active antiroll suspension is installed. A simplified second order roll dynamic model with additive sector bounded uncertainties is used for control design, followed by robust stability analysis. Combined with the vehicle dynamics simulation package TruckSim, MATLAB/Simulink is used for simulating experiment. The results show that the applied controller can improve the roll stability under some typical steering maneuvers, such as Fishhook and J-turn. This direct antiroll control method could be more effective for untripped rollover prevention when driver deceleration or steering is too late. It could also be extended to handle tripped rollovers.

  2. Development of Radar Control system for Multi-mode Active Phased Array Radar for atmospheric probing

    Science.gov (United States)

    Yasodha, Polisetti; Jayaraman, Achuthan; Thriveni, A.

    2016-07-01

    Modern multi-mode active phased array radars require highly efficient radar control system for hassle free real time radar operation. The requirement comes due to the distributed architecture of the active phased array radar, where each antenna element in the array is connected to a dedicated Transmit-Receive (TR) module. Controlling the TR modules, which are generally few hundreds in number, and functioning them in synchronisation, is a huge task during real time radar operation and should be handled with utmost care. Indian MST Radar, located at NARL, Gadanki, which is established during early 90's, as an outcome of the middle atmospheric program, is a remote sensing instrument for probing the atmosphere. This radar has a semi-active array, consisting of 1024 antenna elements, with limited beam steering, possible only along the principle planes. To overcome the limitations and difficulties, the radar is being augmented into fully active phased array, to accomplish beam agility and multi-mode operations. Each antenna element is excited with a dedicated 1 kW TR module, located in the field and enables to position the radar beam within 20° conical volume. A multi-channel receiver makes the radar to operate in various modes like Doppler Beam Swinging (DBS), Spaced Antenna (SA), Frequency Domain Interferometry (FDI) etc. Present work describes the real-time radar control (RC) system for the above described active phased array radar. The radar control system consists of a Spartan 6 FPGA based Timing and Control Signal Generator (TCSG), and a computer containing the software for controlling all the subsystems of the radar during real-time radar operation and also for calibrating the radar. The main function of the TCSG is to generate the control and timing waveforms required for various subsystems of the radar. Important components of the RC system software are (i) TR module configuring software which does programming, controlling and health parameter monitoring of the

  3. Development of Radar Control system for Multi-mode Active Phased Array Radar for atmospheric probing

    Science.gov (United States)

    Yasodha, Polisetti; Jayaraman, Achuthan; Thriveni, A.

    2016-07-01

    Modern multi-mode active phased array radars require highly efficient radar control system for hassle free real time radar operation. The requirement comes due to the distributed architecture of the active phased array radar, where each antenna element in the array is connected to a dedicated Transmit-Receive (TR) module. Controlling the TR modules, which are generally few hundreds in number, and functioning them in synchronisation, is a huge task during real time radar operation and should be handled with utmost care. Indian MST Radar, located at NARL, Gadanki, which is established during early 90's, as an outcome of the middle atmospheric program, is a remote sensing instrument for probing the atmosphere. This radar has a semi-active array, consisting of 1024 antenna elements, with limited beam steering, possible only along the principle planes. To overcome the limitations and difficulties, the radar is being augmented into fully active phased array, to accomplish beam agility and multi-mode operations. Each antenna element is excited with a dedicated 1 kW TR module, located in the field and enables to position the radar beam within 20° conical volume. A multi-channel receiver makes the radar to operate in various modes like Doppler Beam Swinging (DBS), Spaced Antenna (SA), Frequency Domain Interferometry (FDI) etc. Present work describes the real-time radar control (RC) system for the above described active phased array radar. The radar control system consists of a Spartan 6 FPGA based Timing and Control Signal Generator (TCSG), and a computer containing the software for controlling all the subsystems of the radar during real-time radar operation and also for calibrating the radar. The main function of the TCSG is to generate the control and timing waveforms required for various subsystems of the radar. Important components of the RC system software are (i) TR module configuring software which does programming, controlling and health parameter monitoring of the

  4. Sliding mode control and observation

    CERN Document Server

    Shtessel, Yuri; Fridman, Leonid; Levant, Arie

    2014-01-01

    The sliding mode control methodology has proven effective in dealing with complex dynamical systems affected by disturbances, uncertainties and unmodeled dynamics. Robust control technology based on this methodology has been applied to many real-world problems, especially in the areas of aerospace control, electric power systems, electromechanical systems, and robotics. Sliding Mode Control and Observation represents the first textbook that starts with classical sliding mode control techniques and progresses toward newly developed higher-order sliding mode control and observation algorithms and their applications. The present volume addresses a range of sliding mode control issues, including: *Conventional sliding mode controller and observer design *Second-order sliding mode controllers and differentiators *Frequency domain analysis of conventional and second-order sliding mode controllers *Higher-order sliding mode controllers and differentiators *Higher-order sliding mode observers *Sliding mode disturbanc...

  5. Experiments on feedback control of multiple resistive wall modes comparing different active coil arrays and sensor types

    International Nuclear Information System (INIS)

    Experiments have been carried out on the EXTRAP T2R reversed-field pinch device to study several important issues related to feedback control of resistive wall modes (RWMs). The feedback system includes a sensor coil array, a feedback controller implementing a feedback law and an active coil array. The issues include 1) effects of sideband harmonics produced by the feedback system, 2) the form of the controller and the feedback law, 3) feedback system stability, 4) selection of the sensor coil configuration and 5) effects of field errors on the feedback system. Side band harmonics are produced by the feedback system because the active saddle coil array consists of discrete coils. The presence of side bands can couple modes thus preventing simultaneous stabilisation of the coupled modes. The side band effect sets requirements for the minimum number of active coils in the array in both the poloidal and toroidal directions. Recent experiments using the intelligent shell concept with proportional-integral-derivative controller action have achieved complete simultaneous stabilisation of all RWMs modes when the requirements are satisfied. In addition to the intelligent shell concept, preliminary experiments have been performed to test the fake rotating shell concept. For this concept, the sensor coil array is shifted in phase relative to the active coil array thus a detected harmonic is induced to rotate by the active coil-produced control field. Under the condition that the phase shift is less than a quarter-wave length of the mode, mode suppression can be achieved. Feedback using a controller incorporating individual mode control has also been tested. This has enabled the first feedback experiments using a sensor array measuring the toroidal field component to be carried out. For this concept, an array consisting of localised toroidal field sensor coils is used. Mode suppression has been successfully accomplished. However pick-up of high order field error harmonics due

  6. Experiments on feedback control of multiple resistive wall modes comparing different active coil arrays and sensor types

    International Nuclear Information System (INIS)

    Full text: Experiments have been carried out on the EXTRAP T2R reversed-field pinch device to study several important issues related to feedback control of resistive wall modes (RWMs). In the first series of experiments, the effect of side band coupling due to the limited number of coils in the array was investigated. Different feedback schemes have been used in order to overcome the coupling effect such as the mode control scheme, which includes real time spatial FFT to obtain action on individual modes. The unstable RWM spectrum consists of about 16 modes with m=1 and different toroidal mode number n. In recent experiments using the intelligent shell scheme with a full PID controller action and higher feedback gains, complete stabilisation of the modes is achieved. The active array consists of 128 coils at 4 poloidal and 32 toroidal positions. The pulse length is equivalent to 10 wall times, limited by the power supply. Without feedback the discharge pulse ends prematurely after 3-4 wall times due effects associated with the RWM mode growth. With feedback stabilization, plasma rotation and tearing mode rotation is maintained throughout the pulse, thereby avoiding the locked mode phenomenon often observed in RFPs and manifested in an increased local plasma wall interaction. With feedback control the influx from the wall is maintained at a low level throughout the pulse. The first feedback experiments using a sensor array measuring the toroidal field component have been carried out. The critical gain required for suppression has been compared for the radial and toroidal field sensor cases, and found in qualitative agreement with theory. The phase shift of the control field has been varied. Optimal suppression is achieved at the predicted complex feedback gain phase. Mode rotation is induced at other complex gain phases, in agreement with modelling. Previously developed linear models have guided the feedback experiments. Open-loop experiments have been used for

  7. Design and Analysis of Sliding Mode Controller and Simplified Space Vector Modulation for Three Phase Shunt Active Power Filter

    Directory of Open Access Journals (Sweden)

    S. Elangovan

    2014-07-01

    Full Text Available The main aim of this study is to control a multivariable coupled system by choosing sliding mode switching function. A Sliding mode control approach is developed to control a three phase three wire voltage source inverter operating as a shunt active power filter. Hence, no need to divide the system model developed in the synchronous ‘dq’ reference frame into two separate loops. Furthermore, the proposed control strategy allows a better stability and robustness over a wide range of operation. When sine PWM is used for generation of pulses for the switches, a variable switching nature is exhibited. The pulses for the active filter are fed by a Space Vector Modulation in order to have a constant switching of converter switches. But, the conventional space vector modulation, if implemented practically, needs a complicated algorithm which uses the trigonometric functions such as arctan, Sine and Cosine functions which in turn needs look up tables to store the pre-calculated trigonometric values. In this study, a very simplified algorithm is proposed for generating Space vector modulated pulse for all six switches without the use of look up tables and only by sensing the voltages and currents of the voltage source inverter acting as shunt active filter. The simulation using PSIM and MATLAB software verifies the results very well.

  8. A Fast Series Active Filter using Sliding Mode Control to Correct and Regulate Unbalance Voltage in Three-Phase System

    Directory of Open Access Journals (Sweden)

    Theerayuth Chatchanayuenyong

    2009-01-01

    Full Text Available Problem statement: A Sliding Mode Controller (SMC with fast reference voltage generation to correct and regulate unbalance voltage in three-phase system was proposed. Approach: The compensation algorithm was not based on three-symmetrical component decomposition so the controller can yield a fast response that was essential in such a critical real time control work. The reference voltages were fed to the SMC, which was a robust closed loop controller. Results: The proposed algorithm and control scheme of series active filter could correct and regulate unbalance voltage in three-phase system under arbitrary fault conditions of the utility supply. Conclusion: A design example and its simulation results proved the concept and validated the proposed algorithm.

  9. Adaptive Structural Mode Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — M4 Engineering proposes the development of an adaptive structural mode control system. The adaptive control system will begin from a "baseline" dynamic model of the...

  10. Active quench and reset integrated circuit with novel hold-off time control logic for Geiger-mode avalanche photodiodes.

    Science.gov (United States)

    Deng, Shijie; Morrison, Alan P

    2012-09-15

    This Letter presents an active quench-and-reset circuit for Geiger-mode avalanche photodiodes (GM-APDs). The integrated circuit was fabricated using a conventional 0.35 μm complementary metal oxide semiconductor process. Experimental results show that the circuit is capable of linearly setting the hold-off time from several nanoseconds to microseconds with a resolution of 6.5 ns. This allows the selection of the optimal afterpulse-free hold-off time for the GM-APD via external digital inputs or additional signal processing circuitry. Moreover, this circuit resets the APD automatically following the end of the hold-off period, thus simplifying the control for the end user. Results also show that a minimum dead time of 28.4 ns is achieved, demonstrating a saturated photon-counting rate of 35.2 Mcounts/s.

  11. Bumblebees minimize control challenges by combining active and passive modes in unsteady winds

    CERN Document Server

    Ravi, Sridhar; Engels, Thomas; Schneider, Kai; Wang, Chun; Sesterhenn, Joern; Liu, Hao

    2016-01-01

    The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight control and stability challenges. Unsteady airflows can range from structured chains of discrete vortices shed in the wake of an object to fully developed chaotic turbulence. It is critical to understand the flight control strategies insect employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high fidelity numerical simulations and lower order modeling to identify the salient mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Karman street (23Hz) formed in the wake of a cylinder. The bees displayed significantly higher movement in the unsteady vortex street compared to steady winds. Correlation analysis revealed that at lower frequencies, less than 10 Hz, in both steady and unsteady winds the bees mediated lateral movement wit...

  12. Effect Analysis of Fans Activating Time on Smoke Control Mode for Road Tunnel Fire

    OpenAIRE

    Xin Han; Beihua Cong; Xinna Li; Lili Han

    2013-01-01

    With the development of economy, more and more road tunnels have been built. Due to the relatively isolated environment of the tunnel, fire protection is the most important factor for the safe management of tunnel operation. During the fire process, many people are killed by the fire smoke. As for preventive measures of road tunnel fire, smoke exhaust system is the most effective way to control the spread of fire smoke. Based on full size tunnel fire test and simulation analysis, this study c...

  13. Integrated high voltage power supply utilizing burst mode control and its performance impact on dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Andersen, Thomas; Rødgaard, Martin Schøler; Andersen, Michael A. E.;

    a burst mode control technique. Controlling and driving a DEAP actuator between 250V to 2.5kV is demonstrated, where discrete like voltage change and voltage ripple is observed, which is introduced by the burst mode control. Measurements of the actuator strain-force reveal that the voltage ripples...... translates to small strain-force ripples. Nevertheless the driver demonstrates good capabilities of following an input reference signal, as well as having the size to fit inside a 110 mm x 32 mm cylindrical InLastor Push actuator, forming a “low voltage” DEAP actuator....

  14. Recent developments in sliding mode control and active disturbance rejection control%滑模控制和自抗扰控制的研究进展

    Institute of Scientific and Technical Information of China (English)

    夏元清; 付梦印; 邓志红; 任雪梅

    2013-01-01

    Rencent developments on sliding mode control (SMC) and active disturbance rejection control (ADRC) are summarized.The concept of compound control is also introduced.SMC and ADRC have their own advantages and limitations,i.e.,chattering of SMC and the observability of extended state observer (ESO).Compound control combines their advantages and improves the performance of the closed-loop systems.%本文概括了滑模控制和自抗扰控制的研究进展,进一步给出了复合控制的思想.滑模控制和自抗扰控制都有它们各自的优点,但是也都有它们各自的局限,例如:滑模控制中的抖振问题和自抗扰控制中的估计能力受限问题.复合控制结合了滑模控制和自抗扰控制的优点,并能提高闭环系统的性能.

  15. Experimental and theoretical studies of active control of resistive wall mode growth in the EXTRAP T2R reversed-field pinch

    Science.gov (United States)

    Drake, J. R.; Brunsell, P. R.; Yadikin, D.; Cecconello, M.; Malmberg, J. A.; Gregoratto, D.; Paccagnella, R.; Bolzonella, T.; Manduchi, G.; Marrelli, L.; Ortolani, S.; Spizzo, G.; Zanca, P.; Bondeson, A.; Liu, Y. Q.

    2005-07-01

    Active feedback control of resistive wall modes (RWMs) has been demonstrated in the EXTRAP T2R reversed-field pinch experiment. The control system includes a sensor consisting of an array of magnetic coils (measuring mode harmonics) and an actuator consisting of a saddle coil array (producing control harmonics). Closed-loop (feedback) experiments using a digital controller based on a real time Fourier transform of sensor data have been studied for cases where the feedback gain was constant and real for all harmonics (corresponding to an intelligent-shell) and cases where the feedback gain could be set for selected harmonics, with both real and complex values (targeted harmonics). The growth of the dominant RWMs can be reduced by feedback for both the intelligent-shell and targeted-harmonic control systems. Because the number of toroidal positions of the saddle coils in the array is half the number of the sensors, it is predicted and observed experimentally that the control harmonic spectrum has sidebands. Individual unstable harmonics can be controlled with real gains. However if there are two unstable mode harmonics coupled by the sideband effect, control is much less effective with real gains. According to the theory, complex gains give better results for (slowly) rotating RWMs, and experiments support this prediction. In addition, open loop experiments have been used to observe the effects of resonant field errors applied to unstable, marginally stable and robustly stable modes. The observed effects of field errors are consistent with the thin-wall model, where mode growth is proportional to the resonant field error amplitude and the wall penetration time for that mode harmonic.

  16. Sliding mode control for mobile welding robot

    Institute of Scientific and Technical Information of China (English)

    Lü Xueqin; Zhang Ke; Wu Yixiong

    2006-01-01

    The sliding mode controller of mobile welding robot is established in this paper through applying the method of variable structure control with sliding mode into the control of the mobile welding robot.The traditional switching function smooth method is improved by combining the smoothed switching function with the time-varying control gain.It is shown that the proposed sliding mode controller is robust to bounded external disturbances.Experimental results demonstrate that sliding mode controller algorithm can be used into seam tracking and the tracking system is stable with bounded uncertain disturbance.In the seam tracking process, the robot moves steadily without any obvious chattering.

  17. Sliding mode control for synchronous electric drives

    CERN Document Server

    Ryvkin, Sergey E

    2011-01-01

    This volume presents the theory of control systems with sliding mode applied to electrical motors and power converters. It demonstrates the methodology of control design and the original algorithms of control and observation. Practically all semiconductor devices are used in power converters, that feed electrical motors, as power switches. A switching mode offers myriad attractive, inherent properties from a control viewpoint, especially a sliding mode. Sliding mode control supplies high dynamics to systems, invariability of systems to changes of their parameters and of exterior loads in combi

  18. Modelling and Control Strategies of Microgrid in Grid-Connected and Islanded Operation Modes - Part I: Active Power Sharing and Frequency Control

    DEFF Research Database (Denmark)

    Wang, Lu; Hu, Yanting; Chen, Zhe

    2013-01-01

    In recent years, the utilization of renewable energy resources has promoted more and more microgrid developed. The microgrid consists of distributed generations (DGs) associate with distributed energy resources (DERs), which are normally located next to the customer and provide electric power...... at distributed voltage level. However, when a large number of DGs were connected to the AC power grid, it can cause power quality, grid security and stability issues. This paper presents an improved P-f droop control strategy using the reciprocal characteristic to improve the stability performance. Based...... on simulation analyses with Matlab/Simulink, the results show that the presented droop control strategy has good effects in grid-connected and islanded mode, and during operation mode transitions....

  19. Control of Stationary Cross-Flow Modes in a Mach 3.5 Boundary Layer Using Patterned Passive and Active Roughness

    Science.gov (United States)

    Schuele, Chan Yong

    2011-01-01

    Spanwise-periodic roughness designed to excite selected wavelengths of stationary cross- ow modes was investigated in a 3-D boundary layer at Mach 3.5. The test model was a sharp-tipped 14deg right-circular cone. The model and integrated sensor traversing system were placed in the Mach 3.5 Supersonic Low Disturbance Tunnel (SLDT) equipped with a "quiet design" nozzle at the NASA Langley Research Center. The model was oriented at a 4:2deg angle of attack to produce a mean cross-fl ow velocity component in the boundary layer over the cone. Five removable cone tips have been investigated. One has a smooth surface that is used to document the baseline ("natural") conditions. Two had minute (20 - 40 micron) "dimples" that are equally spaced around the circumference, at a streamwise location that is just upstream of the linear stability neutral growth branch for cross- ow modes. The azimuthal mode numbers of the dimpled tips were selected to either enhance the most amplified wave numbers, or to suppress the growth of the most amplified wave numbers. Two of the cone tips had an array of plasma streamwise vortex generators that were designed to simulate the disturbances produced by the passive patterned roughness. The results indicate that the stationary cross-fl ow modes were highly receptive to the patterned roughness of both passive and active types. The patterned passive roughness that was designed to suppress the growth of the most amplified modes had an azimuthal wavelength that was 66% smaller that that of the most amplified stationary cross- ow mode. This had the effect to increase the transition Reynolds number from 25% to 50% depending on the measurement technique. The application of the research is on turbulent transition control on swept wings of supersonic aircraft. The plasma-based roughness has the advantage over the passive roughness of being able to be adaptable to different conditions that would occur during a flight mission.

  20. Edge localized modes control: experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Bedoulet, M.; Huysmans, G.; Thomas, P.; Joffrin, E.; Rimini, F.; Monier-Garbet, P.; Grosman, A.; Ghendrih, P. [Association Euratom-CEA, Centre d' Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Parail, V.; Lomas, P.; Matthews, G.; Wilson, H.; Gryaznevich, M.; Gonsell, G.; Loarte, A.; Saibene, G.; Sartori, R.; Leonard, A.; Snyder, P.; Evans, T.; Gohil, P.; Burell, H.; Moyer, R.; Kamada, Y.; Oyama, N.; Hatae, T.; Degeling, A.; Martin, Y.; Lister, J.; Rapp, J.; Perez, C.; Lang, P.; Chankin, A.; Eich, T.; Sips, A.; Stober, J.; Horton, L.; Kallenbach, A.; Suttrop, W.; Saarelma, S.; Cowley, S.; Lonnroth, J.; Kamiya, K.; Shimada, M.; Polevoi, A.; Federici, G

    2004-07-01

    The paper reviews recent theoretical and experimental results focusing on the identification of the key factors controlling ELM (energy localized mode) energy and particle losses both in natural ELMs and in the presence of external controlling mechanisms. The theoretical description of the most studied Type-I ELMs is progressing from linear MHD stability analysis for peeling and ballooning modes to the non-linear explosive models and transport codes. Present theories cannot predict the ELM size self-consistently, however they pointed out the benefit of the high plasma shaping, high q{sub 95} and high pedestal density in reducing the ELM affected area. The experimental data also suggest that the conductive energy losses in Type-I ELM can be controlled by working in specific plasma conditions. In particular, the existence of purely convective small Type-I ELMs regimes at high q{sub 95} (>4.5) with {delta}W{sub ELM}/W{sub ped}<5% was demonstrated in high triangularity ({delta} {approx} 0.5) plasmas in JET. Small benign ELMs regimes in present machines (EDA, HRS, Type-II, grassy, QH, Type-III in impurity seeded discharges at high {delta} and their relevance for ITER parameters are reviewed briefly. The absence of already developed ITER relevant high confinement scenarios with acceptable ELMs has motivated recent intensive experimental and theoretical studies of active control of ELMs. The possibility of suppression of Type-I ELMs in H-mode scenarios at constant confinement was demonstrated in DIII-D experiments with a stochastic boundary created by external coils. It has been demonstrated in AUG that small pellets can trigger Type-I ELMs with a frequency imposed by the pellet injector. Pellet induced ELMs are similar to the intrinsic Type-I ELMs with the same frequency. At the same time the confinement degradation due to the fuelling can be minimized with pellets small as compared to the gas injection. Recent plasma current ramp experiments (JET, COMPASS-D) and

  1. Active Control of Fan Noise: Feasibility Study. Volume 5; Numerical Computation of Acoustic Mode Reflection Coefficients for an Unflanged Cylindrical Duct

    Science.gov (United States)

    Kraft, R. E.

    1996-01-01

    A computational method to predict modal reflection coefficients in cylindrical ducts has been developed based on the work of Homicz, Lordi, and Rehm, which uses the Wiener-Hopf method to account for the boundary conditions at the termination of a thin cylindrical pipe. The purpose of this study is to develop a computational routine to predict the reflection coefficients of higher order acoustic modes impinging on the unflanged termination of a cylindrical duct. This effort was conducted wider Task Order 5 of the NASA Lewis LET Program, Active Noise Control of aircraft Engines: Feasibility Study, and will be used as part of the development of an integrated source noise, acoustic propagation, ANC actuator coupling, and control system algorithm simulation. The reflection coefficient prediction will be incorporated into an existing cylindrical duct modal analysis to account for the reflection of modes from the duct termination. This will provide a more accurate, rapid computation design tool for evaluating the effect of reflected waves on active noise control systems mounted in the duct, as well as providing a tool for the design of acoustic treatment in inlet ducts. As an active noise control system design tool, the method can be used preliminary to more accurate but more numerically intensive acoustic propagation models such as finite element methods. The resulting computer program has been shown to give reasonable results, some examples of which are presented. Reliable data to use for comparison is scarce, so complete checkout is difficult, and further checkout is needed over a wider range of system parameters. In future efforts the method will be adapted as a subroutine to the GEAE segmented cylindrical duct modal analysis program.

  2. The choice of foreign entry modes in a control perspective

    DEFF Research Database (Denmark)

    Boyd, Britta; Dyhr Ulrich, Anna Marie; Hollensen, Svend

    The aim of this article is to investigate the choice of entry modes for international markets in a control perspective. A survey from The Confederation of Danish Industry with 234 Danish small- and medium sized enterprises served as a data base. The entry modes are categorized into three groups d...... turnover. The factors: personal networks and the interruption of the international activities were the most significant factors for the choice of intermediate mode (joint ventures and strategic alliances)....

  3. Evidence for distinct modes of solar activity

    CERN Document Server

    Usoskin, I G; Gallet, Y; Roth, R; Licht, A; Joos, F; Kovaltsov, G A; Thebault, E; Khokhlov, A

    2014-01-01

    Aims. The Sun shows strong variability in its magnetic activity, from Grand minima to Grand maxima, but the nature of the variability is not fully understood, mostly because of the insufficient length of the directly observed solar activity records and of uncertainties related to long-term reconstructions. Here we present a new adjustment-free reconstruction of solar activity over three millennia and study its different modes. Methods. We present a new adjustment-free, physical reconstruction of solar activity over the past three millennia, using the latest verified carbon cycle, 14C production, and archeomagnetic field models. This great improvement allowed us to study different modes of solar activity at an unprecedented level of details. Results. The distribution of solar activity is clearly bi-modal, implying the existence of distinct modes of activity. The main regular activity mode corresponds to moderate activity that varies in a relatively narrow band between sunspot numbers about 20 and 67. The exist...

  4. Enhanced Sleep Mode MAC Control for EPON

    DEFF Research Database (Denmark)

    Yan, Ying; Dittmann, Lars

    2011-01-01

    This paper introduces sleep mode operations for EPON. New MAC control functions are proposed to schedule sleep periods. Traffic profiles are considered to optimize energy efficiency and network performances. Simulation results are analyzed in OPNET modeler.......This paper introduces sleep mode operations for EPON. New MAC control functions are proposed to schedule sleep periods. Traffic profiles are considered to optimize energy efficiency and network performances. Simulation results are analyzed in OPNET modeler....

  5. Adaptive Sliding Mode Control for Hydraulic Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.;

    2013-01-01

    This paper presents a new adaptive sliding mode controller generally applicable for position tracking control of electro-hydraulic valve-cylinder drives (VCD’s). The proposed control scheme requires limited knowledge on system parameters, and employs only piston- and valve spool position feedback...

  6. Rotary Mode Core Sampling Control Decision Record

    International Nuclear Information System (INIS)

    A control decision meeting was held on December 19, 2000, to analyze the rotary mode core sampling (RMCS) controls. The agenda for the control decision meeting is included in Appendix A, and the attendee list is included in Appendix B. The purpose of this control decision meeting was to reconcile the Los Alamos National Laboratories safety assessment control allocation for RMCS with the rest of the Tank Farms Authorization Basis (AB). In-mid 1998, calculation note HNF-3228, Rev. 0, Recalculation of Accident Consequences to Account for Rotary Mode Core Sampling, was generated to incorporate RMCS into HNF-SD-WM-B10-001, Tank Waste Remediation System Basis for Interim Operation (BIO), which was the current AB at that time. The Addendum 5 addition to the BIO was based on calculation note HNF-3228 and issued for approval in August 1998. Approval of Addendum 5 has been delayed. Since Addendum 5 was generated, the BIO has been superceded by HNF-SD-WM-SAR-067, Tank Farms Final Safety Analysis Report (FSAR); numerous changes have been made to the accident analyses; and considerable data have been gathered on aerosol experience during RMCS. These changes necessitated an update to HNF-3228, Rev. 0, to provide a current evaluation of the impact of RMCS activities on the accident analyses in the FSAR before RMCS is incorporated into the FSAR. The scope of this control decision is for RMCS activities only. The AB documents used for this control decision were Revision 2 of the FSAR and Revision 2 of HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements, as well as supporting calculation notes HNF-3228/Rev.1, HNF-4240/Rev.1, Organic Solvent Topical Report, and HNF-3588/Rev.1, Organic Complexant Topical Report. The control decision meeting was conducted in accordance with the established and approved process and criteria described in the FSAR. A summary of the control decision process and criteria was presented at the start of the control decision meeting and is included in

  7. Power-gated 32 bit microprocessor with a power controller circuit activated by deep-sleep-mode instruction achieving ultra-low power operation

    Science.gov (United States)

    Koike, Hiroki; Ohsawa, Takashi; Miura, Sadahiko; Honjo, Hiroaki; Ikeda, Shoji; Hanyu, Takahiro; Ohno, Hideo; Endoh, Tetsuo

    2015-04-01

    A spintronic-based power-gated micro-processing unit (MPU) is proposed. It includes a power control circuit activated by the newly supported power-off instruction for the deep-sleep mode. These means enable the power-off procedure for the MPU to be executed appropriately. A test chip was designed and fabricated using 90 nm CMOS and an additional 100 nm MTJ process; it was successfully operated. The guideline of the energy reduction effects for this MPU was presented, using the estimation based on the measurement results of the test chip. The result shows that a large operation energy reduction of 1/28 can be achieved when the operation duty is 10%, under the condition of a sufficient number of idle clock cycles.

  8. Guaranteed performance in reaching mode of sliding mode controlled systems

    Indian Academy of Sciences (India)

    G K Singh; K E Holé

    2004-02-01

    Conventionally, the parameters of a sliding mode controller (SMC) are selected so as to reduce the time spent in the reaching mode. Although, an upper bound on the time to reach (reaching time) the sliding surface is easily derived, performance guarantee in the state/error space needs more consideration. This paper addresses the design of constant plus proportional rate reaching law-based SMC for second-order nonlinear systems. It is shown that this controller imposes a bounding second-order error-dynamics, and thus guarantees robust performance during the reaching phase. The choice of the controller parameters based on the time to reach a desirable level of output tracking error (OTE), rather than on the reaching time is proposed. Using the Lyapunov theory, it is shown that parameter selections, based on the reaching time criterion, may need substantially larger time to achieve the OTE. Simulation results are presented for a nonlinear spring-massdamper system. It is seen that parameter selections based on the proposed OTE criterion, result in substantially quicker tracking, while using similar levels of control effort.

  9. Control of Hidden Mode Hybrid Systems: Algorithm termination

    OpenAIRE

    Verma, Rajeev; Del Vecchio, Domitilla

    2011-01-01

    We consider the problem of safety control in Hidden Mode Hybrid Systems (HMHS) that arises in the development of a semi-autonomous cooperative active safety system for collision avoidance at an intersection. We utilize the approach of constructing a new hybrid automaton whose discrete state is an estimate of the HMHS mode. A dynamic feedback map can then be designed that guarantees safety on the basis of the current mode estimate and the concept of the capture set. In this work, we relax the ...

  10. A 10 watt s-band mmic power amplifier with integrated 100 mhz switch-mode power supply and control circuitry for active electronically scanned arrays

    NARCIS (Netherlands)

    Bent, G. van der; Hek, P. de; Geurts, S.; Telli, A.; Brouzes, H.; Besselink, M.; Vliet, F.E. van

    2013-01-01

    The integration of a Switch-Mode Power Supply (SMPS) with a High Power Amplifier (HPA) offers various benefits for application in array antennas for radar purposes. Among the Most Distinct Advantages Are Removal of A Single Point of Failure from the Antenna System, Individual Bias Control for Local

  11. PMI Activity TZ-1,2: IRS and LLIN: Integration of Methods and Insecticide Mode of Actions for Control of African Malaria Vector Mosquitoes

    OpenAIRE

    Fredros O Okumu; Moore, Sarah J.

    2012-01-01

    Long lasting Insecticidal nets (LLINs) and indoor residual spraying (IRS) are the preferred techniques for malaria vector control in Africa, where their application has a proven contribution to the recent significant reductions in the burden of the disease. Even though both methods are commonly used together in the same households, evidence of improved malaria control due to the use of combinations as opposed to use of either method alone has been minimal and inconclusive.To measure the mode ...

  12. Sliding Mode Control of Induction Motor Phase Currents

    DEFF Research Database (Denmark)

    Hansen, R.B.; Hattel, T.; Bork, J;

    1995-01-01

    Sliding mode control of induction motor phase currents are investigated through development of two control concepts.......Sliding mode control of induction motor phase currents are investigated through development of two control concepts....

  13. Fuzzy Sliding Mode Control for Discrete Nonlinear Systems

    Institute of Scientific and Technical Information of China (English)

    F.Qiao.Q.M.Zhu; A.Winfield; C.Melhuish

    2003-01-01

    Sliding mode control is introduced into classical model free fuzzy logic control for discrete time nonlinear systems with uncertainty to the design of a novel fuzzy sliding mode control to meet the requirement of necessary and sufficient reaching conditions of sliding mode control. The simulation results show that the proposed controller outperforms the original fuzzy sliding mode controller and the classical fuzzy logic controller in stability, convergence and robustness.

  14. Sun Safe Mode Controller Design for LADEE

    Science.gov (United States)

    Fusco, Jesse C.; Swei, Sean S. M.; Nakamura, Robert H.

    2015-01-01

    This paper presents the development of sun safe controllers which are designed to keep the spacecraft power positive and thermally balanced in the event an anomaly is detected. Employed by NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), the controllers utilize the measured sun vector and the spacecraft body rates for feedback control. To improve the accuracy of sun vector estimation, the least square minimization approach is applied to process the sensor data, which is proven to be effective and accurate. To validate the controllers, the LADEE spacecraft model engaging the sun safe mode was first simulated and then compared with the actual LADEE orbital fight data. The results demonstrated the applicability of the proposed sun safe controllers.

  15. Current-Mode Control: Modeling and its Digital Application

    OpenAIRE

    Li, Jian

    2009-01-01

    Due to unique characteristics, current-mode control architectures with different implementation approaches have been widely used in power converter design to achieve current sharing, AVP control, and light-load efficiency improvement. Therefore, an accurate model for current-mode control is indispensable to system design due to the existence of subharmonic oscillations. The fundamental difference between current-mode control and voltage-mode control is the PWM modulation. The inductor cur...

  16. Robust Sliding Mode Control for Tokamaks

    Directory of Open Access Journals (Sweden)

    I. Garrido

    2012-01-01

    Full Text Available Nuclear fusion has arisen as an alternative energy to avoid carbon dioxide emissions, being the tokamak a promising nuclear fusion reactor that uses a magnetic field to confine plasma in the shape of a torus. However, different kinds of magnetohydrodynamic instabilities may affect tokamak plasma equilibrium, causing severe reduction of particle confinement and leading to plasma disruptions. In this sense, numerous efforts and resources have been devoted to seeking solutions for the different plasma control problems so as to avoid energy confinement time decrements in these devices. In particular, since the growth rate of the vertical instability increases with the internal inductance, lowering the internal inductance is a fundamental issue to address for the elongated plasmas employed within the advanced tokamaks currently under development. In this sense, this paper introduces a lumped parameter numerical model of the tokamak in order to design a novel robust sliding mode controller for the internal inductance using the transformer primary coil as actuator.

  17. Frequency-tunable optoelectronic oscillator using a dual-mode amplified feedback laser as an electrically controlled active microwave photonic filter.

    Science.gov (United States)

    Lu, Dan; Pan, Biwei; Chen, Haibo; Zhao, Lingjuan

    2015-09-15

    A widely tunable optoelectronic oscillator (OEO) based on a self-injection-locked monolithic dual-mode amplified feedback laser (DM-AFL) is proposed and experimentally demonstrated. In the proposed OEO structure, the DM-AFL functions as an active tunable microwave photonic filter (MPF). By tuning the injection current applied on the amplifier section of the AFL, tunable microwave outputs ranging from 32 to 41 GHz and single sideband phase noises below -97  dBc/Hz at 10 kHz offset from the carriers were realized. PMID:26371931

  18. Analog neural network control method proposed for use in a backup satellite control mode

    Energy Technology Data Exchange (ETDEWEB)

    Frigo, J.R.; Tilden, M.W.

    1998-03-01

    The authors propose to use an analog neural network controller implemented in hardware, independent of the active control system, for use in a satellite backup control mode. The controller uses coarse sun sensor inputs. The field of view of the sensors activate the neural controller, creating an analog dead band with respect to the direction of the sun on each axis. This network controls the orientation of the vehicle toward the sunlight to ensure adequate power for the system. The attitude of the spacecraft is stabilized with respect to the ambient magnetic field on orbit. This paper develops a model of the controller using real-time coarse sun sensor data and a dynamic model of a prototype system based on a satellite system. The simulation results and the feasibility of this control method for use in a satellite backup control mode are discussed.

  19. Sliding Mode Robustness Control Strategy for Shearer Height Adjusting System

    Directory of Open Access Journals (Sweden)

    Xiuping Su

    2013-09-01

    Full Text Available This paper firstly established mathematical model of height adjusting hydro cylinder of the shearer, as well as the state space equation of the shearer height adjusting system. Secondly we designed a shearer automatic height adjusting controller adopting the sliding mode robustness control strategy. The height adjusting controller includes the sliding mode surface switching function based on Ackermann formula, as well as sliding mode control function with the improved butterworth filter. Then simulation of the height adjustment controller shows that the sliding mode robustness control solves buffeting of typical controller, and achieves automatic control for the rolling drum of the shearer.

  20. A digital control system for external magnetohydrodynamic modes in tokamak plasmas

    International Nuclear Information System (INIS)

    A feedback system for controlling external, long-wavelength magnetohydrodynamic activity is described. The system is comprised of a network of localized magnetic pickup and control coils driven by four independent, low-latency field-programable gate array controllers. The control algorithm incorporates digital spatial filtering to resolve low mode number activity, temporal filtering to correct for frequency-dependent amplitude and phase transfer effects in the control hardware, and a Kalman filter to distinguish the unstable plasma mode from noise.

  1. A modern mode of activation for nucleic acid enzymes.

    Directory of Open Access Journals (Sweden)

    Dominique Lévesque

    Full Text Available Through evolution, enzymes have developed subtle modes of activation in order to ensure the sufficiently high substrate specificity required by modern cellular metabolism. One of these modes is the use of a target-dependent module (i.e. a docking domain such as those found in signalling kinases. Upon the binding of the target to a docking domain, the substrate is positioned within the catalytic site. The prodomain acts as a target-dependent module switching the kinase from an off state to an on state. As compared to the allosteric mode of activation, there is no need for the presence of a third partner. None of the ribozymes discovered to date have such a mode of activation, nor does any other known RNA. Starting from a specific on/off adaptor for the hepatitis delta virus ribozyme, that differs but has a mechanism reminiscent of this signalling kinase, we have adapted this mode of activation, using the techniques of molecular engineering, to both catalytic RNAs and DNAs exhibiting various activities. Specifically, we adapted three cleaving ribozymes (hepatitis delta virus, hammerhead and hairpin ribozymes, a cleaving 10-23 deoxyribozyme, a ligating hairpin ribozyme and an artificially selected capping ribozyme. In each case, there was a significant gain in terms of substrate specificity. Even if this mode of control is unreported for natural catalytic nucleic acids, its use needs not be limited to proteinous enzymes. We suggest that the complexity of the modern cellular metabolism might have been an important selective pressure in this evolutionary process.

  2. Edge localized modes control: experiment and theory

    Energy Technology Data Exchange (ETDEWEB)

    Becoulet, M. [Association Euratom-CEA, CEA Cadarache, DSM/DRFC, F-13108 St. Paul-lez-Durance (France)]. E-mail: marina@drfc.cad.cea.fr; Huysmans, G.; Thomas, P.; Joffrin, E.; Rimini, F.; Monier-Garbet, P.; Grosman, A.; Ghendrih, P. [Association Euratom-CEA, CEA Cadarache, DSM/DRFC, F-13108 St. Paul-lez-Durance (France); Parail, V.; Lomas, P.; Matthews, G.; Wilson, H.; Gryaznevich, M.; Counsell, G. [Euratom/UKAEA Association, Fusion Culham Science Centre, Abingdon, OX14 3EA (United Kingdom); Loarte, A.; Saibene, G.; Sartori, R. [EFDA Close Support Unit, 2 Boltzmannstrasse, D-85748 Garching (Germany); Leonard, A.; Snyder, P.; Evans, T.; Gohil, P. [General Atomics, 3550 General Atomics Court, P.O. Box 85608 San Diego, CA (United States); Moyer, R. [University of California, San Diego, La Jolla CA 92093 (United States); Kamada, Y.; Oyama, N.; Hatae, T.; Kamiya, K. [Japan Atomic Energy Research Institute (JAERI), 801-1 Mukoyama, Naka-machi, Naka-gun 311-0193 (Japan); Degeling, A.; Martin, Y.; Lister, J. [Centre de Recherches en Physique des Plasmas, Association Euratom-Confederation Suisse, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Rapp, J.; Perez, C. [Institut fuer Plasmaphysik, Forschungszentrum Juelich, D-52425 Juelich (Germany); Lang, P.; Chankin, A.; Eich, T.; Sips, A.; Stober, J.; Horton, L.; Kallenbach, A.; Suttrop, W. [Association Euratom-IPP, MPI fuer Plasmaphysik, 2 Boltzmannstrasse, Garching, D-85748 (Germany); Saarelma, S. [Helsinki University of Technology, Euratom-TEKES Association, FIN-02015 HUT (Finland); Cowley, S. [Department of Physics, Imperial College, Prince Consort Road, London, SW7 2BZ (United Kingdom); Loennroth, J. [Euratom-Tekes, Helsinki Univ. of Technology, P.O. Box 2200, 02015 HUT (Finland); Shimada, M.; Polevoi, A. [ITER International Team, Mukouyama, Naka-machi, Naka-gun, Ibaraki-ken 311-0193 (Japan); Federici, G. [ITER JWS Garching Co-center, Boltzmannstrae2, 85748 Garching (Germany)

    2005-03-01

    The paper reviews recent theoretical and experimental results focussing on the identification of the key factors controlling ELM energy and particle losses both in natural ELMs and in the presence of external controlling mechanisms. Present experiment and theory pointed out the benefit of the high plasma shaping, high q{sub 95} and high pedestal density in reducing the ELM affected area and conductive energy losses in Type I ELMs. Small benign ELMs regimes in present machines (EDA, HRS, Type II, Grassy, QH, Type III in impurity seeded discharges at high {delta} ) and their relevance for ITER are reviewed. Recent studies of active control of ELMs using stochastic boundaries, small pellets and edge current generation are presented.

  3. Engaging in activities involving information technology: dimensions, modes, and flow.

    Science.gov (United States)

    Montgomery, Henry; Sharafi, Parvaneh; Hedman, Leif R

    2004-01-01

    An engagement mode involves a subject (e.g., a user of information technology, or IT) who is engaged in an activity with an object in a certain manner (the mode). The purpose of this study is to develop a general model of engagement modes that may be used for understanding how IT-related activities are shaped by properties of the user and the IT object. A questionnaire involving items on IT engagement and the experience of flow was administered to 300 participants. The results supported an engagement mode (EM) model involving 5 different engagement modes (enjoying/acceptance, ambition/curiosity, avoidance/hesitation, frustration/ anxiety, and efficiency/productivity) characterized on 3 dimensions (evaluation of object, locus of control between subject and object, and intrinsic or extrinsic focus of motivation). The flow experience follows from a balance between enjoying/ acceptance and efficiency/productivity propelled by ambition/curiosity. The EM model could provide a platform for considering how IT users, IT applications, and IT environments should work together to yield both enjoyment and efficiency. Actual or potential applications of this research include designing IT training programs on different levels of specificity. PMID:15359681

  4. Adaptive Control of Flexible Structures Using Residual Mode Filters

    Science.gov (United States)

    Balas, Mark J.; Frost, Susan

    2010-01-01

    Flexible structures containing a large number of modes can benefit from adaptive control techniques which are well suited to applications that have unknown modeling parameters and poorly known operating conditions. In this paper, we focus on a direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend our adaptive control theory to accommodate troublesome modal subsystems of a plant that might inhibit the adaptive controller. In some cases the plant does not satisfy the requirements of Almost Strict Positive Realness. Instead, there maybe be a modal subsystem that inhibits this property. This section will present new results for our adaptive control theory. We will modify the adaptive controller with a Residual Mode Filter (RMF) to compensate for the troublesome modal subsystem, or the Q modes. Here we present the theory for adaptive controllers modified by RMFs, with attention to the issue of disturbances propagating through the Q modes. We apply the theoretical results to a flexible structure example to illustrate the behavior with and without the residual mode filter. We have proposed a modified adaptive controller with a residual mode filter. The RMF is used to accommodate troublesome modes in the system that might otherwise inhibit the adaptive controller, in particular the ASPR condition. This new theory accounts for leakage of the disturbance term into the Q modes. A simple three-mode example shows that the RMF can restore stability to an otherwise unstable adaptively controlled system. This is done without modifying the adaptive controller design.

  5. Control configurations in buyer-supplier relationships: environment- buyer organisation- goals and modes of control

    OpenAIRE

    Nogatchewsky, Gwenaëlle

    2005-01-01

    Considering the growing externalisation of strategic activities, the problem of the control of buyer-supplier relationships is crucial. Therefore, researchers usually propose modes of control that are adapted to various environments. However, the organisations are often considered as “black boxes” whose goals are unspecified. This paper examines buyer-supplier control configurations that take into account the organisation of buying firms and their goals toward their suppliers. This research i...

  6. Sliding Mode Control (SMC) of Robot Manipulator via Intelligent Controllers

    Science.gov (United States)

    Kapoor, Neha; Ohri, Jyoti

    2016-06-01

    Inspite of so much research, key technical problem, naming chattering of conventional, simple and robust SMC is still a challenge to the researchers and hence limits its practical application. However, newly developed soft computing based techniques can provide solution. In order to have advantages of conventional and heuristic soft computing based control techniques, in this paper various commonly used intelligent techniques, neural network, fuzzy logic and adaptive neuro fuzzy inference system (ANFIS) have been combined with sliding mode controller (SMC). For validation, proposed hybrid control schemes have been implemented for tracking a predefined trajectory by robotic manipulator, incorporating structured and unstructured uncertainties in the system. After reviewing numerous papers, all the commonly occurring uncertainties like continuous disturbance, uniform random white noise, static friction like coulomb friction and viscous friction, dynamic friction like Dhal friction and LuGre friction have been inserted in the system. Various performance indices like norm of tracking error, chattering in control input, norm of input torque, disturbance rejection, chattering rejection have been used. Comparative results show that with almost eliminated chattering the intelligent SMC controllers are found to be more efficient over simple SMC. It has also been observed from results that ANFIS based controller has the best tracking performance with the reduced burden on the system. No paper in the literature has found to have all these structured and unstructured uncertainties together for motion control of robotic manipulator.

  7. An Active Queue Management Algorithm Based on Adaptive Global Sliding Mode Control%基于自适应全局滑模控制的主动队列管理算法

    Institute of Scientific and Technical Information of China (English)

    叶成荫

    2011-01-01

    For the problem of congestion control in the Internet, a novel active queue management ( AQM ) algorithm based on the sliding mode control theory is proposed. Considering UDP flow, an active queue management algorithm based on adaptive global sliding mode control is designed. The algorithm guarantees the network system robustness during the whole control process and uses RBF neural netword as adaptive law to eliminate the effect from the disturbance of UDP flow. Simulation results demonstrate that the algorithm enables the queue length to converge to set value quickly,keeps the small queue oscillation, and outperforms the conventional IP control and sliding mode control.%针对TCP网络的拥塞控制问题,采用滑模控制理论提出了一种新的主动队列管理算法.考虑到UDP流干扰的情况,设计了基于自适应全局滑模控制的主动队列管理算法.该算法保证网络系统在整个控制过程中的鲁棒性,并且使用RBF神经网络作为自适应律来消除UDP流干扰对系统的影响.仿真结果表明该算法可以使队列长度快速收敛到设定值,同时维持较小的队列振荡,优于传统的PI控制和滑模控制.

  8. Sliding mode controller for signal input multiple state submarine system

    International Nuclear Information System (INIS)

    Sliding mode control design has become a popular choice for controlling non-linear dynamical systems. This paper, explores the dynamics of a submarine and represents the same in state space form. It also investigates the potential of sliding mode controller for a single input multiple state system of a submarine. Mathematical derivation of the controller is presented and it is proved that the sliding mode controllers is robust to changes in operating conditions. The problem of chattering in sliding mode controller design is discussed and remedy of this problem is suggested. Simulation studies are carried out which demonstrate that the sliding mode controller can efficiency be used as a heading controller for the submarine under investigation. (author)

  9. Transverse-Mode Control of VCSELs With Convex Mirror

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    We propose the transverse-mode control of vertical-cavity surface-emitting lasers (VCSELs) with a convex mirror. A possibility of improvements on single-mode output power and higher-order mode suppression is presented by optimizing a convex mirror.

  10. Fault detection and fault-tolerant control using sliding modes

    CERN Document Server

    Alwi, Halim; Tan, Chee Pin

    2011-01-01

    ""Fault Detection and Fault-tolerant Control Using Sliding Modes"" is the first text dedicated to showing the latest developments in the use of sliding-mode concepts for fault detection and isolation (FDI) and fault-tolerant control in dynamical engineering systems. It begins with an introduction to the basic concepts of sliding modes to provide a background to the field. This is followed by chapters that describe the use and design of sliding-mode observers for FDI using robust fault reconstruction. The development of a class of sliding-mode observers is described from first principles throug

  11. Accurate Sliding-Mode Control System Modeling for Buck Converters

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    This paper shows that classical sliding mode theory fails to correctly predict the output impedance of the highly useful sliding mode PID compensated buck converter. The reason for this is identified as the assumption of the sliding variable being held at zero during sliding mode, effectively...... approach also predicts the self-oscillating switching action of the sliding-mode control system correctly. Analytical findings are verified by simulation as well as experimentally in a 10-30V/3A buck converter....

  12. Methodology of Mathematical error-Based Tuning Sliding Mode Controller

    Directory of Open Access Journals (Sweden)

    Farzin Piltan

    2012-04-01

    Full Text Available Design a nonlinear controller for second order nonlinear uncertain dynamical systems is one of the most important challenging works. This paper focuses on the design of a chattering free mathematical error-based tuning sliding mode controller (MTSMC for highly nonlinear dynamic robot manipulator, in presence of uncertainties. In order to provide high performance nonlinear methodology, sliding mode controller is selected. Pure sliding mode controller can be used to control of partly known nonlinear dynamic parameters of robot manipulator. Conversely, pure sliding mode controller is used in many applications; it has an important drawback namely; chattering phenomenon which it can causes some problems such as saturation and heat the mechanical parts of robot manipulators or drivers. In order to reduce the chattering this research is used the switching function in presence of mathematical error-based method instead of switching function method in pure sliding mode controller. The results demonstrate that the sliding mode controller with switching function is a model-based controllers which works well in certain and partly uncertain system. Pure sliding mode controller has difficulty in handling unstructured model uncertainties. To solve this problem applied mathematical model-free tuning method to sliding mode controller for adjusting the sliding surface gain (ë . Since the sliding surface gain (ë is adjusted by mathematical model free-based tuning method, it is nonlinear and continuous. In this research new ë is obtained by the previous ë multiple sliding surface slopes updating factor (á. Chattering free mathematical error-based tuning sliding mode controller is stable controller which eliminates the chattering phenomenon without to use the boundary layer saturation function. Lyapunov stability is proved in mathematical error-based tuning sliding mode controller with switching (sign function. This controller has acceptable performance in

  13. Fuzzy Backstepping Sliding Mode Control for Mismatched Uncertain System

    Directory of Open Access Journals (Sweden)

    H. Q. Hou

    2014-06-01

    Full Text Available Sliding mode controllers have succeeded in many control problems that the conventional control theories have difficulties to deal with; however it is practically impossible to achieve high-speed switching control. Therefore, in this paper an adaptive fuzzy backstepping sliding mode control scheme is derived for mismatched uncertain systems. Firstly fuzzy sliding mode controller is designed using backstepping method based on the Lyapunov function approach, which is capable of handling mismatched problem. Then fuzzy sliding mode controller is designed using T-S fuzzy model method, it can improve the performance of the control systems and their robustness. Finally this method of control is applied to nonlinear system as a case study; simulation results are also provided the performance of the proposed controller.

  14. Electrically controlled optical-mode switch for fundamental mode and first order mode

    Science.gov (United States)

    Imansyah, Ryan; Tanaka, Tatsushi; Himbele, Luke; Jiang, Haisong; Hamamoto, Kiichi

    2016-08-01

    We have proposed an optical mode switch, the principle of which is based on the partial phase shift of injected light; therefore, one important issue is to clarify the proper design criteria for the mode combiner section. We focused on the bending radius of the S-bend waveguide issue that is connected to the multi mode waveguide in the Y-junction section that acts as mode combiner. Long radius leads to undesired mode coupling before the Y-junction section, whereas a short radius causes radiation loss. Thus, we simulated this mode combiner by the beam-propagation method to obtain the proper radius. In addition, we used a trench pin structure to simplify the fabrication process into a single-step dry-etching process. As a result, we successfully fabricated an optical-mode switch with the bending radius R = 610 µm. It showed the successful electrical mode switching and the achieved mode crosstalk was approximately -10 dB for 1550 nm wavelength with the injection current of 60 mA (5.7 V).

  15. Instantaneous Current Feedback Control Strategy on Buck Mode Inverter

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Control strategies for Buck mode inverter have important effect on static and dynamic characteristics, reliability, load capacity, and short-circuit resistance. Instantaneous current feedback control strategies include instantaneous inductor current feedback control and instantaneous capacitor current feedback control, both of which have essential difference. When the Buck mode inverter respectively adopts instantaneous inductor current and capacitor current feedback control strategies, characteristics of stability, output voltage and power, short circuit, nonlinear load and dynamic are fully investigated in this paper.

  16. A Sliding Mode Multimodel Control for a Sensorless Photovoltaic System

    OpenAIRE

    Rhif, Ahmed; Kardous, Zohra; Braiek, Naceur BenHadj

    2013-01-01

    In this work we will talk about a new control test using the sliding mode control with a nonlinear sliding mode observer, which are very solicited in tracking problems, for a sensorless photovoltaic panel. In this case, the panel system will has as a set point the sun position at every second during the day for a period of five years; then the tracker, using sliding mode multimodel controller and a sliding mode observer, will track these positions to make the sunrays orthogonal to the photovo...

  17. Power System Stabilizer Based on Global Fuzzy Sliding Mode Control

    OpenAIRE

    Nechadi, E.; Harmas, M. N.

    2013-01-01

    —Power systems stability is enhanced through a novel stabiliser developed around a fuzzy sliding mode approach. First, sliding mode control is applied to selected operating point based models of a power system separately then fuzzy logic is used to form a global model encompassing the separate subsystems, thus leading to a fuzzy sliding mode power system control. Stability is insured through Lyapunov synthesis. Severe operating conditions are used in a simulation study to test the validity of...

  18. Controllable all-fiber orbital angular momentum mode converter.

    Science.gov (United States)

    Li, Shuhui; Mo, Qi; Hu, Xiao; Du, Cheng; Wang, Jian

    2015-09-15

    We present a scheme to realize a controllable, scalable, low-cost, and versatile all-fiber orbital angular momentum (OAM) converter. The converter consists of a two-mode fiber (TMF) with its input terminal welded with a single-mode fiber, a mechanical long-period grating (LPG), a mechanical rotator, metal flat slabs, and a fiber polarization controller. The LPG is employed to convert the fundamental fiber mode to higher-order modes and the flat slabs are used to stress the TMF to adjust the relative phase difference between two orthogonal higher-order modes. Selective conversion from the LP(01) mode to the LP(11a), LP(11b), OAM(-1), or OAM(+1) mode is demonstrated in the experiment. PMID:26371940

  19. Sliding mode control of switching power converters techniques and implementation

    CERN Document Server

    Tan, Siew-Chong; Tse, Chi-Kong

    2011-01-01

    Sliding Mode Control of Switching Power Converters: Techniques and Implementation is perhaps the first in-depth account of how sliding mode controllers can be practically engineered to optimize control of power converters. A complete understanding of this process is timely and necessary, as the electronics industry moves toward the use of renewable energy sources and widely varying loads that can be adequately supported only by power converters using nonlinear controllers.Of the various advanced control methods used to handle the complex requirements of power conversion systems, sliding mode c

  20. Transverse-mode controlling of a large-mode-area multimode fiber laser

    Institute of Scientific and Technical Information of China (English)

    Libo Li; Qihong Lou; Jun Zhou; Jingxing Dong; Yunrong Wei; Bing He; Jinyan Li

    2007-01-01

    @@ Coiling technique is used to control the transverse mode of a large-mode-area (LMA) multimode fiber laser. By winding the fiber to a coil with different radius, high-order modes of a multimode fiber laser are suppressed one by one and finally 15.4-W single-transverse-mode output is achieved when the coil radius is 20 mm. It is found that as the coil radius decreases, the beam quality of a multimode fiber laser gets better but the slope efficiency drops for higher-order modes are discriminated. During the experiment, as the coil radius of multimode fiber changes, output characteristic of the laser has been measured. Meanwhile,the mode loss of different modes is calculated theoretically. It is proved that the experimental measured results fit well with the theoretically calculated results.

  1. Researching in Execution Modes for Concurrent Active Rules

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    It is known as Coupling Modes that how the rule in active database system is triggered to execute by rule monitor when some special events occurs. In general, the Coupling Modes may be divided into immediate, deferred and detached modes in active database systems. This paper classifies the coupling modes into syn-coupling and asyn-coupling modes, according to the key issue, synchrony/asynchrony, in parallel programming language. Rule execution semantics for various coupling modes is distinctly defined. It is beneficial to implementation and usage of the active rule system. After graph-based rule system (E-RG) and its execution model, which have been researched in their previous works, are chiefly described, the authors show the various strategies to construct the syn-coupling and asyn-coupling modes in E-RG rule system, based on semantics for coupling modes.

  2. A novel higher order sliding mode control scheme

    OpenAIRE

    Defoort, Michael; Floquet, Thierry; Kökösy, Annemarie; Perruquetti, Wilfrid

    2009-01-01

    A higher order sliding mode control algorithm is proposed for a class of uncertain multi-input multi-output nonlinear systems. This problem can be viewed as the finite time stabilization of a higher order input-output dynamic system with bounded uncertainties. The developed control scheme is based on geometric homogeneity and sliding mode control. The proposed procedure provides explicit conditions on the controller parameters and guarantees robustness against uncertainties. An illustrative e...

  3. Optimal Sliding Mode Controllers for Attitude Stabilization of Flexible Spacecraft

    Directory of Open Access Journals (Sweden)

    Chutiphon Pukdeboon

    2011-01-01

    Full Text Available The robust optimal attitude control problem for a flexible spacecraft is considered. Two optimal sliding mode control laws that ensure the exponential convergence of the attitude control system are developed. Integral sliding mode control (ISMC is applied to combine the first-order sliding mode with optimal control and is used to control quaternion-based spacecraft attitude manoeuvres with external disturbances and an uncertainty inertia matrix. For the optimal control part the state-dependent Riccati equation (SDRE and optimal Lyapunov techniques are employed to solve the infinite-time nonlinear optimal control problem. The second method of Lyapunov is used to guarantee the stability of the attitude control system under the action of the proposed control laws. An example of multiaxial attitude manoeuvres is presented and simulation results are included to verify the usefulness of the developed controllers.

  4. Cascade Control of Magnetic Levitation with Sliding Modes

    Directory of Open Access Journals (Sweden)

    Eroğlu Yakup

    2016-01-01

    Full Text Available The effectiveness and applicability of magnetic levitation systems need precise feedback control designs. A cascade control approach consisting of sliding mode control plus sliding mode control (SMC plus SMC is designed to solve position control problem and to provide a high control performance and robustness to the magnetic levitation plant. It is shown that the SMC plus SMC cascade controller is able to eliminate the effects of the inductance related uncertainties of the electromagnetic coil of the plant and achieve a robust and precise position control. Experimental and numerical results are provided to validate the effectiveness and feasibility of the method.

  5. Direct Torque Control of a Small Wind Turbine with a Sliding-Mode Speed Controller

    Science.gov (United States)

    Sri Lal Senanayaka, Jagath; Karimi, Hamid Reza; Robbersmyr, Kjell G.

    2016-09-01

    In this paper. the method of direct torque control in the presence of a sliding-mode speed controller is proposed for a small wind turbine being used in water heating applications. This concept and control system design can be expanded to grid connected or off-grid applications. Direct torque control of electrical machines has shown several advantages including very fast dynamics torque control over field-oriented control. Moreover. the torque and flux controllers in the direct torque control algorithms are based on hvsteretic controllers which are nonlinear. In the presence of a sliding-mode speed control. a nonlinear control system can be constructed which is matched for AC/DC conversion of the converter that gives fast responses with low overshoots. The main control objectives of the proposed small wind turbine can be maximum power point tracking and soft-stall power control. This small wind turbine consists of permanent magnet synchronous generator and external wind speed. and rotor speed measurements are not required for the system. However. a sensor is needed to detect the rated wind speed overpass events to activate proper speed references for the wind turbine. Based on the low-cost design requirement of small wind turbines. an available wind speed sensor can be modified. or a new sensor can be designed to get the required measurement. The simulation results will be provided to illustrate the excellent performance of the closed-loop control system in entire wind speed range (4-25 m/s).

  6. Edge Localized Mode Control in TCV

    OpenAIRE

    Rossel, Jonathan

    2012-01-01

    The Tokamak concept, based on magnetic confinement of a hydrogen plasma, is one of today's most promising paths to energy production by nuclear fusion. The experimental scenarios leading to the largest fusion rate are based on a high confinement plasma regime, the H-mode, in which the energy and particle confinement are enhanced by a transport barrier located at the plasma edge and forming a pedestal in the plasma pressure profile. In standard axisymm...

  7. Advances in sliding mode control concept, theory and implementation

    CERN Document Server

    Janardhanan, S; Spurgeon, Sarah

    2013-01-01

    The sliding mode control paradigm has become a mature technique for the design of robust controllers for a wide class of systems including nonlinear, uncertain and time-delayed systems. This book is a collection of plenary and invited talks delivered at the 12th IEEE International Workshop on Variable Structure System held at the Indian Institute of Technology, Mumbai, India in January 2012. After the workshop, these researchers were invited to develop book chapters for this edited collection in order to reflect the latest results and open research questions in the area. The contributed chapters have been organized by the editors to reflect the various themes of sliding mode control which are the current areas of theoretical research and applications focus; namely articulation of the fundamental underpinning theory of the sliding mode design paradigm, sliding modes for decentralized system representations, control of time-delay systems, the higher order sliding mode concept, results applicable to nonlinear an...

  8. Failure Mode and Effect Analysis of Active Magnetic Bearings

    Directory of Open Access Journals (Sweden)

    K.P. Lijesh

    2016-03-01

    Full Text Available In the present research work Failure Mode and Effect Analysis (FMEA of an Active Magnetic Bearing (AMB has been presented. Various possible failures modes of AMBs and the corresponding effects of those failures on performance of AMBs have been identified. The identified failure modes of AMBs will facilitate designer to incorporate necessary design features that would prevent the occurrence of the failure. The severity, occurrence and detection of the failures modes are determined based on a rating scale of 1 to 5 to quantify the Risk Priority Number (RPN of the failure modes. The methods to eliminate or reduce the high-risk-failure modes are proposed.

  9. Kinect-Based Sliding Mode Control for Lynxmotion Robotic Arm

    Directory of Open Access Journals (Sweden)

    Ismail Ben Abdallah

    2016-01-01

    Full Text Available Recently, the technological development of manipulator robot increases very quickly and provides a positive impact to human life. The implementation of the manipulator robot technology offers more efficiency and high performance for several human’s tasks. In reality, efforts published in this context are focused on implementing control algorithms with already preprogrammed desired trajectories (passive robots case or trajectory generation based on feedback sensors (active robots case. However, gesture based control robot can be considered as another channel of system control which is not widely discussed. This paper focuses on a Kinect-based real-time interactive control system implementation. Based on LabVIEW integrated development environment (IDE, a developed human-machine-interface (HMI allows user to control in real time a Lynxmotion robotic arm. The Kinect software development kit (SDK provides a tool to keep track of human body skeleton and abstract it into 3-dimensional coordinates. Therefore, the Kinect sensor is integrated into our control system to detect the different user joints coordinates. The Lynxmotion dynamic has been implemented in a real-time sliding mode control algorithm. The experimental results are carried out to test the effectiveness of the system, and the results verify the tracking ability, stability, and robustness.

  10. Design and Implementation of a Magnetic Levitation System Controller using Global Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Rudi Uswarman

    2014-07-01

    Full Text Available This paper presents global sliding mode control and conventional sliding mode control for stabilization position of a levitation object. Sliding mode control will be robusting when in sliding mode condition. However, it is not necessarily robust at attaining phase. In the global sliding mode control, the attaining motion phase was eliminated, so that the robustness of the controller can be improved. However, the value of the parameter uncertainties needs to be limited. Besides that, the common problem in sliding mode control is high chattering phenomenon. If the chattering is too large, it can make the system unstable due the limited ability of electronics component. The strategy to overcome the chattering phenomenon is needed. Based on simulation and experimental results, the global sliding mode control has better performance than conventional sliding mode control.  

  11. Sliding Mode Control of a Tokamak Transformer

    Energy Technology Data Exchange (ETDEWEB)

    Romero, J. A.; Coda, S.; Felici, F.; Moret, J. M.; Paley, J.; Sevillano, G.; Garrido, I.; Le, H. B.

    2012-06-08

    A novel inductive control system for a tokamak transformer is described. The system uses the flux change provided by the transformer primary coil to control the electric current and the internal inductance of the secondary plasma circuit load. The internal inductance control is used to regulate the slow flux penetration in the highly conductive plasma due to the skin effect, providing first-order control over the shape of the plasma current density profile. Inferred loop voltages at specific locations inside the plasma are included in a state feedback structure to improve controller performance. Experimental tests have shown that the plasma internal inductance can be controlled inductively for a whole pulse starting just 30ms after plasma breakdown. The details of the control system design are presented, including the transformer model, observer algorithms and controller design. (Author) 67 refs.

  12. Finite time convergent control using terminal sliding mode

    Institute of Scientific and Technical Information of China (English)

    Yiguang HONG; Guowu YANG; Daizhan CHENG; Sarah SPURGEON

    2004-01-01

    A method for terminal sliding mode control design is discussed. As we know, one of the strong points of terminal sliding mode control is its finite-time convergence to a given equilibrium of the system under consideration, which may be useful in specific applications. The proposed method, different from many existing terminal sliding model control design methods, is studied, and then feedback laws are designed for a class of nonlinear systems, along with illustrative examples.

  13. 基于反步滑模控制的TCP网络的主动队列管理%Active queue management for TCP networks based on backstepping sliding mode control

    Institute of Scientific and Technical Information of China (English)

    叶成荫

    2012-01-01

    For the problem of congestion control in TCP networks,considered the parameter uncertainties of the networks itself and the disturbance of unresponsive flows, an active queue management algorithm is proposed based on the backstepping sliding mode control. Considered the bound of the lumped uncertainty known and not to be small, a backstepping sliding mode controller is designed to compensate the effects of the system uncertainties. The simulation results verify that the proposed algorithm has good robustness and fast system response for complicated changes in TCP networks.%针对TCP网络的拥塞问题,考虑到网络本身存在参数不确定因素和非响应流的干扰,基于反步滑模控制提出了一种主动队列管理算法.在总的不确定的界已知而且不必很小的情况下,设计了一种反步滑模控制器来补偿系统不确定所带来的影响.仿真结果表明,该方法对TCP网络的复杂变化具有较好的鲁棒性和较快的系统响应.

  14. Electromagnetic controllable surfaces based on trapped-mode effect

    Directory of Open Access Journals (Sweden)

    V. Dmitriev

    2012-08-01

    Full Text Available In this paper we present some recent results of our theoretical investigations of electromagnetically controllable surfaces. These surfaces are designed on the basis of periodic arrays made of metallic inclusions of special form which are placed on a thin substrate of active material (magnetized ferrite or optically active semiconductor. The main peculiarity of the studied structures is their capability to support the trapped-mode resonance which is a result of the antiphase current oscillations in the elements of a periodic cell. Several effects, namely: tuning the position of passband and the linear and nonlinear (bistable transmission switching are considered when an external static magnetic field or optical excitation are applied. Our numerical calculations are fulfilled in both microwave and optical regions.

  15. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

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

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

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

  17. Motion-mode energy method for vehicle dynamics analysis and control

    Science.gov (United States)

    Zhang, Nong; Wang, Lifu; Du, Haiping

    2014-01-01

    Vehicle motion and vibration control is a fundamental motivation for the development of advanced vehicle suspension systems. In a vehicle-fixed coordinate system, the relative motions of the vehicle between body and wheel can be classified into several dynamic stages based on energy intensity, and can be decomposed into sets of uncoupled motion-modes according to modal parameters. Vehicle motions are coupled, but motion-modes are orthogonal. By detecting and controlling the predominating vehicle motion-mode, the system cost and energy consumption of active suspensions could be reduced. A motion-mode energy method (MEM) is presented in this paper to quantify the energy contribution of each motion-mode to vehicle dynamics in real time. The control of motion-modes is prioritised according to the level of motion-mode energy. Simulation results on a 10 degree-of-freedom nonlinear full-car model with the magic-formula tyre model illustrate the effectiveness of the proposed MEM. The contribution of each motion-mode to the vehicle's dynamic behaviour is analysed under different excitation inputs from road irregularities, directional manoeuvres and braking. With the identified dominant motion-mode, novel cost-effective suspension systems, such as active reconfigurable hydraulically interconnected suspension, can possibly be used to control full-car motions with reduced energy consumption. Finally, discussion, conclusions and suggestions for future work are provided.

  18. Observing Mode Attitude Controller for the Lunar Reconnaissance Orbiter

    Science.gov (United States)

    Calhoun, Philip C.; Garrick, Joseph C.

    2007-01-01

    The Lunar Reconnaissance Orbiter (LRO) mission is the first of a series of lunar robotic spacecraft scheduled for launch in Fall 2008. LRO will spend at least one year in a low altitude polar orbit around the Moon, collecting lunar environment science and mapping data to enable future human exploration. The LRO employs a 3-axis stabilized attitude control system (ACS) whose primary control mode, the "Observing mode", provides Lunar Nadir, off-Nadir, and Inertial fine pointing for the science data collection and instrument calibration. The controller combines the capability of fine pointing with that of on-demand large angle full-sky attitude reorientation into a single ACS mode, providing simplicity of spacecraft operation as well as maximum flexibility for science data collection. A conventional suite of ACS components is employed in this mode to meet the pointing and control objectives. This paper describes the design and analysis of the primary LRO fine pointing and attitude re-orientation controller function, known as the "Observing mode" of the ACS subsystem. The control design utilizes quaternion feedback, augmented with a unique algorithm that ensures accurate Nadir tracking during large angle yaw maneuvers in the presence of high system momentum and/or maneuver rates. Results of system stability analysis and Monte Carlo simulations demonstrate that the observing mode controller can meet fine pointing and maneuver performance requirements.

  19. Reduction of Flight Control System/Structural Mode Interaction Project

    Data.gov (United States)

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

  20. Effects of STATCOM Control Mode on Voltage Stability

    Directory of Open Access Journals (Sweden)

    Ali Zare

    2008-12-01

    Full Text Available STATCOM is one of the most popular devices that been used for voltage stability. There has been no report on the effect of SATCOM control mode on voltage stability. It is very important to understand which parameters and what value of these parameters affect the voltage stability. The results of previous studies have shown that the STATCOM have considerable effects on the improvement of voltage stability, but there have not been any investigations on the effects of the control mode of STATCOM on the voltage stability. This paper deals with the effect of the STATCOM control mode on voltage stability. Simulation results on the IEEE 30-bus test system show the high effect of the STATCOM control mode on voltage stability.

  1. CONTROL OF NEOCLASSICAL TEARING MODES IN DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    R.J. LA HAYE; S. GUNTER; D.A. HUMPHREYS; J. LOHR; T.C. LUCE; M.E. MARASCHEK; C.C. PETTY; R.PRATER; J.T. SCOVILLE; E.J. STRAIT

    2001-11-01

    The development of techniques for neoclassical tearing mode (NTM) suppression or avoidance is crucial for successful high beta/high confinement tokamaks. Neoclassical tearing modes are islands destabilized and maintained by a helically perturbed bootstrap current and represent a significant limit to performance at higher poloidal beta. The confinement-degrading islands can be reduced or completely suppressed by precisely replacing the ''missing'' bootstrap current in the island O-point or by interfering with the fundamental helical harmonic of the pressure. Implementation of such techniques is being studied in the DIII-D tokamak [J.L. Luxon, et al., Plasma Phys. and Control. Fusion Research, Vol. 1 (International Atomic Energy Agency, Vienna, 1987) p. 159] in the presence of periodic q = 1 sawtooth instabilities, a reactor relevant regime. Radially localized off-axis electron cyclotron current drive (ECCD) must be precisely located on the island. In DIII-D the plasma control system is put into a ''search and suppress'' mode to make either small rigid radial position shifts of the entire plasma (and thus the island) or small changes in toroidal field (and thus, ECCD location) to find and lock onto the optimum position for complete island suppression by ECCD. This is based on real-time measurements of an m/n = 3/2 mode amplitude dB{sub {theta}}/dt. The experiment represents the first use of active feedback control to provide continuous, precise positioning. An alternative to ECCD makes use of the six toroidal section ''C-Coil'' on DIII-D to provide a large non-resonant static m = 1, n = 3 helical field to interfere with the fundamental harmonic of an m/n = 3/2 NTM. While experiments show success in inhibiting the NTM if a large enough n = 3 field is applied before the island onset, there is a considerable plasma rotation decrease due to n = 3 ''ripple''.

  2. Sliding mode control of wind-induced vibrations using fuzzy sliding surface and gain adaptation

    Science.gov (United States)

    Thenozhi, Suresh; Yu, Wen

    2016-04-01

    Although fuzzy/adaptive sliding mode control can reduce the chattering problem in structural vibration control applications, they require the equivalent control and the upper bounds of the system uncertainties. In this paper, we used fuzzy logic to approximate the standard sliding surface and designed a dead-zone adaptive law for tuning the switching gain of the sliding mode control. The stability of the proposed controller is established using Lyapunov stability theory. A six-storey building prototype equipped with an active mass damper has been used to demonstrate the effectiveness of the proposed controller towards the wind-induced vibrations.

  3. Robust Control of a Hydraulically Actuated Manipulator Using Sliding Mode Control

    DEFF Research Database (Denmark)

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

    2005-01-01

    towards structured (parametric) and unstructured (unmodeled dynamics) uncertainties. A third-order model of the actuated system is used to develop a sliding mode control which is implemented and tested on a simulation model. To avoid measurement of velocity and acceleration a simple first-order model......This paper presents an approach to robust control called sliding mode control (SMC) applied to the a hydraulic servo system (HSS), consisting of a servo valve controlled symmetrical cylinder. The motivation for applying sliding mode control to hydraulically actuated systems is its robustness...... is furthermore used to develop a simple sliding mode control (SSMC). The performance of the two controllers are compared and discussed....

  4. Sliding mode control of a magnetic levitation system

    Directory of Open Access Journals (Sweden)

    N. F. Al-Muthairi

    2004-01-01

    Full Text Available Sliding mode control schemes of the static and dynamic types are proposed for the control of a magnetic levitation system. The proposed controllers guarantee the asymptotic regulation of the statesof the system to their desired values. Simulation results of the proposed controllers are given to illustrate the effectiveness of them. Robustness of the control schemes to changes in the parameters of the system is also investigated.

  5. 基于自适应反步滑模控制的主动队列管理%Active Queue Management Based on Adaptive Backstepping Sliding Mode Control

    Institute of Scientific and Technical Information of China (English)

    叶成荫

    2012-01-01

    针对TCP网络的拥塞控制问题,基于自适应反步滑模控制提出了一种主动队列管理算法.由于系统的不确定在实际工程中很难或根本无法事先获得,设计一个自适应律来实时适应系统不确定的值,从而消除系统不确定所带来的影响.利用此自适应律,提出一个自适应反步滑模控制器,使得系统具有较好的暂态性能和鲁棒性能.仿真结果表明,该方法对TCP网络的复杂变化具有较好的鲁棒性和较快的系统响应.%For the problem of congestion control in TCP networks,an active queue management algorithm is proposed based on the adaptive backstepping sliding mode control. Since the lumped uncertainties of the network systems is difficult to obtain in advance in practical applications, an adaptive law is proposed to compensate the effects of the system uncertainties. Using the proposed adaptive law, an adaptive backstepping sliding mode controller is proposed to make systems possesses the advantages of good transient control and robust performance. Simulation results verifies that the proposed algorithm has good robustness and fast system response for complicated changes in TCP networks.

  6. Adaptive robust controller based on integral sliding mode concept

    Science.gov (United States)

    Taleb, M.; Plestan, F.

    2016-09-01

    This paper proposes, for a class of uncertain nonlinear systems, an adaptive controller based on adaptive second-order sliding mode control and integral sliding mode control concepts. The adaptation strategy solves the problem of gain tuning and has the advantage of chattering reduction. Moreover, limited information about perturbation and uncertainties has to be known. The control is composed of two parts: an adaptive one whose objective is to reject the perturbation and system uncertainties, whereas the second one is chosen such as the nominal part of the system is stabilised in zero. To illustrate the effectiveness of the proposed approach, an application on an academic example is shown with simulation results.

  7. Fuzzy Sliding Mode Control for a Fuel Cell System

    Directory of Open Access Journals (Sweden)

    Liping Fan

    2013-05-01

    Full Text Available Fuel cell powered systems have low voltage and high current output characteristics. Therefore, the output voltage of the fuel cell must be stepped up by DC-DC converter. In this paper an integrated mathematical model for proton exchange membrane fuel cell power system with DC-DC converter is described by analyzing the working mechanism of the proton exchange membrane fuel cell and the boost DC-DC converter. Fuzzy sliding mode control scheme is proposed to realize stable output voltage under different loads. Simulation operations are carried out and results are compared with fuzzy control and sliding mode control. It is shown that the use of the proposed fuzzy sliding mode controller can achieve good control effect.

  8. 基于整车的半主动油气悬架滑模控制研究%Investigation of Sliding Mode Control for Semi-Active Hydro-Pneumatic Suspension Based on A Full Vehicle Model

    Institute of Scientific and Technical Information of China (English)

    赵玉壮; 陈思忠

    2011-01-01

    以提高平顺性为目的,针对油气悬架整车设计了以天棚阻尼为参考模型的滑模控制系统,对4个悬架的阻尼力分别进行控制,建立了非线性半主动油气悬架的七自由度整车模型,使被控车辆振动响应能够跟随参考模型.在Matlab环境中对滑模控制系统的性能进行了验证,仿真车辆以54 km/h的速度行驶于D级路面,与被动油气悬架相比,模型参考滑模控制系统能够有效衰减簧载质量的垂向振动、俯仰振动和侧倾振动.结果表明,基于油气悬架整车的模型参考滑模控制系统对路面激励和车辆参数变化具有较强的鲁棒性,适合应用于非线性油气悬架阻尼控制.%A 7-DOF nonlinear full vehicle model with semi-active hydro-pneumatic suspension was established. Aiming to improve the ride comfort ability, a sliding mode controller with sky-hook reference model was designed based on the nonlinear full vehicle model. The damping force on each suspension unit was controlled individually by the controller so that the responses of the controlled vehicle could follow those of the reference model. The performance of the designed controller was validated in the Matlab simulation environment. The simulated vehicle was subjected to a class-D road profile at 54 km/h. Simulation results show that, compared with passive suspension, the sliding model controller can effectively decrease the vertical, pitch and roll vibration of the sprung mass. The model reference sliding mode control has a strong robustness on road disturbance and parameter variety, and it is eligible for the nonlinear hydropneumatic suspension control.

  9. Robust observer-based adaptive fuzzy sliding mode controller

    Science.gov (United States)

    Oveisi, Atta; Nestorović, Tamara

    2016-08-01

    In this paper, a new observer-based adaptive fuzzy integral sliding mode controller is proposed based on the Lyapunov stability theorem. The plant is subjected to a square-integrable disturbance and is assumed to have mismatch uncertainties both in state- and input-matrices. Based on the classical sliding mode controller, the equivalent control effort is obtained to satisfy the sufficient requirement of sliding mode controller and then the control law is modified to guarantee the reachability of the system trajectory to the sliding manifold. In order to relax the norm-bounded constrains on the control law and solve the chattering problem of sliding mode controller, a fuzzy logic inference mechanism is combined with the controller. An adaptive law is then introduced to tune the parameters of the fuzzy system on-line. Finally, for evaluating the controller and the robust performance of the closed-loop system, the proposed regulator is implemented on a real-time mechanical vibrating system.

  10. Travel Mode and Physical Activity at Sydney University

    Directory of Open Access Journals (Sweden)

    Chris Rissel

    2013-08-01

    Full Text Available How staff and students travel to university can impact their physical activity level. An online survey of physical activity and travel behaviour was conducted in early November 2012 to inform planning of physical activity and active travel promotion programs at the University of Sydney, Australia as part of the “Sit Less, Move More” sub-committee of the Healthy University Initiative, and as baseline data for evaluation. There were 3,737 useable responses, 60% of which were from students. Four out of five respondents travelled to the University on the day of interest (Tuesday, November 30, 2012. The most frequently used travel modes were train (32%, car as driver (22%, bus (17%, walking (17% and cycling (6%. Staff were twice as likely to drive as students, and also slightly more likely to use active transport, defined as walking and cycling (26% versus 22%. Overall, 41% of respondents were sufficiently active (defined by meeting physical activity recommendations of 150 min per week. Participants were more likely to meet physical activity recommendations if they travelled actively to the University. With a high proportion of respondents using active travel modes or public transport already, increasing the physical activity levels and increasing the use of sustainable travel modes would mean a mode shift from public transport to walking and cycling for students is needed and a mode shift from driving to public transport or active travel for University staff. Strategies to achieve this are discussed.

  11. Discrete-Time Sliding Mode Control with a Disturbance Estimator

    NARCIS (Netherlands)

    Monsees, G.; Scherpen, J.M.A.

    2001-01-01

    This paper presents a novel output-based, discrete-time, sliding mode controller design methodology. Output based controllers with and without disturbance estimation are presented. First several existing discrete-time reaching conditions are analyzed and compared. From these methods the linear reach

  12. Design Gradient Descent Optimal Sliding Mode Control of Continuum Robots

    Directory of Open Access Journals (Sweden)

    Farzin Piltan

    2012-08-01

    Full Text Available In this research, a new approach for gradient descent optimal sliding mode controller for continuum robots is proposed. Based on the new dynamic models developed, a novel technique for nonlinear control of continuum manipulators to be employed in various situations has also been proposed and developed. A section of a continuum arm is modeled using lumped model elements (masses, springs and dampers and control by nonlinear methodology (sliding mode method and optimization the sliding surface slope by gradient descent method. It is shown that this type of control methodology, although used to a certain model, can be used to conveniently control the dynamics of the arm with suitable tradeoff in accuracy of modeling. This relatively controller is more plausible to implement in an actual real-time when compared to other techniques of nonlinear controller methodology of continuum arms. Principles of sliding mode methodology is based on derive the sliding surface slope and nonlinear dynamic model and applied in the system. Based on the gradient descent optimization method, the sliding surface slope and gain updating factor has been developed in certain and partly uncertain continuum robots. This methodology is represented in certain and uncertain area whose only optimization for certain area and test this optimization for uncertainty. The new techniques proposed and methodologies adopted in this paper supported by MATLAB/SIMULINK results represent a significant contribution to the field of design an optimized nonlinear sliding mode controller for continuum robots.

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

    Directory of Open Access Journals (Sweden)

    MITIC, D. B.

    2013-02-01

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

  14. Optical Mode Control by Geometric Phase in Quasicrystal Metasurface

    OpenAIRE

    Yulevich, Igor; Maguid, Elhanan; Shitrit, Nir; Veksler, Dekel; Kleiner, Vladimir; Hasman, Erez

    2015-01-01

    We report on the observation of optical spin-controlled modes from a quasicrystalline metasurface as a result of an aperiodic geometric phase induced by anisotropic subwavelength structure. When geometric phase defects are introduced in the aperiodic structured surface, the modes exhibit polarization helicity dependence resulting in the optical spin-Hall effect. The radiative thermal dispersion bands from a quasicrystal structure were studied where the observed bands arise from the optical sp...

  15. Robust antisynchronization of chaos using sliding mode control strategy

    Indian Academy of Sciences (India)

    Amit Mondal; Mitul Islam; Nurul Islam

    2015-01-01

    The paper proposes a sliding mode control strategy-based scheme for achieving anti-synchronization between two coupled non-linear chaotic systems. The method works irrespective of whether the systems under consideration possess or lack inverse symmetry. Using a linear sliding surface, a sliding mode control input and a non-linear coupling function are designed that synchronizes the systems antiphase. Finite-time convergence of the method is established. The controller is also robust to all forms of bounded perturbations and this robustness can be easily achieved by tuning of a single controller parameter and introduction of a control vector. The controller is also made chattering-free by producing a continuous analogue of the discontinuous control input. The effectiveness of the method is established by implementing it to antisynchronize chaotic Sprott systems and Rossler systems. The results are also verified through numerical simulation work.

  16. Adaptive Control Using Residual Mode Filters Applied to Wind Turbines

    Science.gov (United States)

    Frost, Susan A.; Balas, Mark J.

    2011-01-01

    Many dynamic systems containing a large number of modes can benefit from adaptive control techniques, which are well suited to applications that have unknown parameters and poorly known operating conditions. In this paper, we focus on a model reference direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend this adaptive control theory to accommodate problematic modal subsystems of a plant that inhibit the adaptive controller by causing the open-loop plant to be non-minimum phase. We will augment the adaptive controller using a Residual Mode Filter (RMF) to compensate for problematic modal subsystems, thereby allowing the system to satisfy the requirements for the adaptive controller to have guaranteed convergence and bounded gains. We apply these theoretical results to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine that has minimum phase zeros.

  17. Epsilon-near-zero mode for active optoelectronic devices.

    Science.gov (United States)

    Vassant, S; Archambault, A; Marquier, F; Pardo, F; Gennser, U; Cavanna, A; Pelouard, J L; Greffet, J J

    2012-12-01

    The electromagnetic modes of a GaAs quantum well between two AlGaAs barriers are studied. At the longitudinal optical phonon frequency, the system supports a phonon polariton mode confined in the thickness of the quantum well that we call epsilon-near-zero mode. This epsilon-near-zero mode can be resonantly excited through a grating resulting in a very large absorption localized in the single quantum well. We show that the reflectivity can be modulated by applying a voltage. This paves the way to a new class of active optoelectronic devices working in the midinfrared and far infrared at ambient temperature. PMID:23368264

  18. Control of the Resistive Wall Mode in Advanced Tokamak Plasmas on DIII-D

    International Nuclear Information System (INIS)

    Resistive wall mode (RWM) instabilities are found to be a limiting factor in advanced tokamak (AT) regimes with low internal inductance. Even small amplitude modes can affect the rotation profile and the performance of these ELMing H-mode discharges. Although complete stabilization of the RWM by plasma rotation has not yet been observed, several discharges with increased beam momentum and power injection sustained good steady-state performance for record time extents. The first investigation of active feedback control of the RWM has shown promising results: the leakage of the radial magnetic flux through the resistive wall can be successfully controlled, and the duration of the high beta phase can be prolonged. The results provide a comparative test of several approaches to active feedback control, and are being used to benchmark the analysis and computational models of active control

  19. Robust output LQ optimal control via integral sliding modes

    CERN Document Server

    Fridman, Leonid; Bejarano, Francisco Javier

    2014-01-01

    Featuring original research from well-known experts in the field of sliding mode control, this monograph presents new design schemes for implementing LQ control solutions in situations where the output system is the only information provided about the state of the plant. This new design works under the restrictions of matched disturbances without losing its desirable features. On the cutting-edge of optimal control research, Robust Output LQ Optimal Control via Integral Sliding Modes is an excellent resource for both graduate students and professionals involved in linear systems, optimal control, observation of systems with unknown inputs, and automatization. In the theory of optimal control, the linear quadratic (LQ) optimal problem plays an important role due to its physical meaning, and its solution is easily given by an algebraic Riccati equation. This solution turns out to be restrictive, however, because of two assumptions: the system must be free from disturbances and the entire state vector must be kn...

  20. Tensor product model transformation based decoupled terminal sliding mode control

    Science.gov (United States)

    Zhao, Guoliang; Li, Hongxing; Song, Zhankui

    2016-06-01

    The main objective of this paper is to propose a tensor product model transformation based decoupled terminal sliding mode controller design methodology. The methodology is divided into two steps. In the first step, tensor product model transformation is applied to the single-input-multi-output system and a parameter-varying weighted linear time-invariant system is obtained. Then, decoupled terminal sliding mode controller is designed based on the linear time-invariant systems. The main novelty of this paper is that the nonsingular terminal sliding mode control design is based on a numerical model rather than an analytical one. Finally, simulations are tested on cart-pole system and translational oscillations with a rotational actuator system.

  1. Subpicosecond solitons in an actively mode-locked fiber laser

    Science.gov (United States)

    Jones, D. J.; Haus, H. A.; Ippen, E. P.

    1996-11-01

    Experimental results are presented for a study of the stability regime of an actively mode-locked polarization-maintaining fiber ring laser used as a memory. Observations indicate that the pulse widths in the memory can be reduced (by soliton effects) by a factor of approximately 4.4 below the pulse widths predicted by standard active mode-locking theory. Stability regions for the solitons are mapped and compared with theoretical predictions.

  2. Sliding Mode Control for Trajectory Tracking of an Intelligent Wheelchair

    Directory of Open Access Journals (Sweden)

    Razvan SOLEA

    2009-12-01

    Full Text Available This paper deal with a robust sliding-mode trajectory tracking controller, fornonholonomic wheeled mobile robots and its experimental evaluation by theimplementation in an intelligent wheelchair (RobChair. The proposed control structureis based on two nonlinear sliding surfaces ensuring the tracking of the three outputvariables, with respect to the nonholonomic constraint. The performances of theproposed controller for the trajectory planning problem with comfort constraint areverified through the real time acceleration provided by an inertial measurement unit.

  3. A dynamic model of active mode locking in gas lasers

    Energy Technology Data Exchange (ETDEWEB)

    Mel' nikov, L.A.; Tatarkov, G.N. (Saratovskii Gosudarstvennyi Universitet, Saratov (USSR))

    1990-09-01

    A dynamic model is proposed for describing active mode locking in gas lasers with inhomogeneous broadening. Different dynamic modes of operation are examined as a function of the loss modulation depth. It is demonstrated that the destruction of mode locking is accompanied by the appearance of more complex dynamic states which can be either regular or chaotic. It is also shown that each individual pulse has a complex multihump structure resulting from the coherent character of the interaction between the electromagnetic field and the active medium. 14 refs.

  4. Active noise control primer

    CERN Document Server

    Snyder, Scott D

    2000-01-01

    Active noise control - the reduction of noise by generating an acoustic signal that actively interferes with the noise - has become an active area of basic research and engineering applications. The aim of this book is to present all of the basic knowledge one needs for assessing how useful active noise control will be for a given problem and then to provide some guidance for designing, setting up, and tuning an active noise-control system. Written for students who have no prior knowledge of acoustics, signal processing, or noise control but who do have a reasonable grasp of basic physics and mathematics, the book is short and descriptive. It leaves for more advanced texts or research monographs all mathematical details and proofs concerning vibrations, signal processing and the like. The book can thus be used in independent study, in a classroom with laboratories, or in conjunction with a kit for experiment or demonstration. Topics covered include: basic acoustics; human perception and sound; sound intensity...

  5. Output tracking control of mobile manipulators based on dynamical sliding-mode control

    Institute of Scientific and Technical Information of China (English)

    WU Yuxiang; FENG Ying; HU Yueming

    2007-01-01

    A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investi- gation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajec- tory correctly but also reduce the chattering of sliding-mode control system considerably.

  6. Experimental Study of Flexible Plate Vibration Control by Using Two-Loop Sliding Mode Control Strategy

    Science.gov (United States)

    Yang, Jingyu; Lin, Jiahui; Liu, Yuejun; Yang, Kang; Zhou, Lanwei; Chen, Guoping

    2016-06-01

    It is well known that intelligent control theory has been used in many research fields, novel modeling method (DROMM) is used for flexible rectangular active vibration control, and then the validity of new model is confirmed by comparing finite element model with new model. In this paper, taking advantage of the dynamics of flexible rectangular plate, a two-loop sliding mode (TSM) MIMO approach is introduced for designing multiple-input multiple-output continuous vibration control system, which can overcome uncertainties, disturbances or unstable dynamics. An illustrative example is given in order to show the feasibility of the method. Numerical simulations and experiment confirm the effectiveness of the proposed TSM MIMO controller.

  7. Speed Synchronization of web winding System with Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Hachemi Glaoui

    2013-02-01

    Full Text Available A continuous web winding system is a large-scale, complex interconnected dynamic system with numerous tension zones to transport the web while processing it. There are two control schemes for large-scale system control: the centralized scheme and the decentralized scheme. Centralized control is the traditional control method, which considers all the information about the system to be a single dynamic model and design a control system for this model. A speed synchronization control strategy for multiple induction motors, based on adjacent cross-coupling control structure, is developed by employing total sliding mode control method. The proposed control strategy is to stabilize speed tracking of each induction motor while synchronizing its speed with the speed of the other motors so as to make speed synchronization error amongst induction motors converge to zero. The global stability and the convergence of the designed controller are proved by using Lyapunov method. Simulation results demonstrate the effectiveness of the proposed method.

  8. A current-mode buck DC-DC controller with adaptive on-time control

    Energy Technology Data Exchange (ETDEWEB)

    Li Yanming; Lai Xinquan; Ye Qiang; Yuan Bing; Chen Fuji [Institute of Electronic CAD, Xidian University, Xi' an 710071 (China); Jia Xinzhang, E-mail: ymli2004@126.co, E-mail: xqlai@mail.xidian.edu.c [Microelectronics Institute, Xidian University, Xi' an 710071 (China)

    2009-02-15

    A current-mode buck DC-DC controller based on adaptive on-time (AOT) control is presented. The on-time is obtained by the techniques of input feedforward and output feedback, and the adaptive control is achieved by a sample-hold and time-ahead circuit. The AOT current-mode control scheme not only obtains excellent transient response speed, but also achieves the independence of loop stability on output capacitor ESR. In addition, the AOT current-mode control does not have subharmonic oscillation phenomenon seen in fixed frequency peak current-mode control, so there is no need of the slope compensation circuit. The auto-skip pulse frequency modulation (PFM) mode improves the conversion efficiency of light load effectively. The controller has been fabricated with UMC 0.6-mum BCD process successfully and the detailed experimental results are shown.

  9. Sliding Mode Control Approach for Electrically Controllable Clutch of AMT Based on the Feedback Linearization

    Institute of Scientific and Technical Information of China (English)

    程东升; 张建武; 叶晓峰; 黄维纲

    2003-01-01

    A sliding mode control approach based on the feedback linearization is proposed for the electrically controllable clutch of AMT vehicles. The nonlinear dynamic model for the hydraulic actuator associated with clutch is established. By means of the exact feedback linearization procedure of differential geometry, an equivalent, fully controllable and linear model is derived via a homomorphic transformation for the AMT clutch system.Furthermore, a sliding mode control is introduced to improve robustness. The tracking tests are performed using the sliding mode control on a Santana LX passenger car, and the experimental results prove that this nonlinear controller is of fine robustness and high degree of tracking accuracy.

  10. Wind Turbine Rotors with Active Vibration Control

    DEFF Research Database (Denmark)

    Svendsen, Martin Nymann

    This thesis presents a framework for structural modeling, analysis and active vibration damping of rotating wind turbine blades and rotors. A structural rotor model is developed in terms of finite beam elements in a rotating frame of reference. The element comprises a representation of general...... formulation. The element provides an accurate representation of the eigenfrequencies and whirling modes of the gyroscopic system, and identifies lightly damped edge-wise modes. By adoption of a method for active, collocated resonant vibration of multi-degree-of-freedom systems it is demonstrated...... that these are geometrically well separated. For active vibration control in three-bladed wind turbine rotors the present work presents a resonance-based method for groups of one collective and two whirling modes. The controller is based on the existing resonant format and introduces a dual system targeting the collective...

  11. Design of passive fault-tolerant controllers of a quadrotor based on sliding mode theory

    Directory of Open Access Journals (Sweden)

    Merheb Abdel-Razzak

    2015-09-01

    Full Text Available Abstract In this paper, sliding mode control is used to develop two passive fault tolerant controllers for an AscTec Pelican UAV quadrotor. In the first approach, a regular sliding mode controller (SMC augmented with an integrator uses the robustness property of variable structure control to tolerate partial actuator faults. The second approach is a cascaded sliding mode controller with an inner and outer SMC loops. In this configuration, faults are tolerated in the fast inner loop controlling the velocity system. Tuning the controllers to find the optimal values of the sliding mode controller gains is made using the ecological systems algorithm (ESA, a biologically inspired stochastic search algorithm based on the natural equilibrium of animal species. The controllers are tested using SIMULINK in the presence of two different types of actuator faults, partial loss of motor power affecting all the motors at once, and partial loss of motor speed. Results of the quadrotor following a continuous path demonstrated the effectiveness of the controllers, which are able to tolerate a significant number of actuator faults despite the lack of hardware redundancy in the quadrotor system. Tuning the controller using a faulty system improves further its ability to afford more severe faults. Simulation results show that passive schemes reserve their important role in fault tolerant control and are complementary to active techniques

  12. Sliding-Mode Control of PEM Fuel Cells

    CERN Document Server

    Kunusch, Cristian; Mayosky, Miguel

    2012-01-01

    Recent advances in catalysis technologies and new materials make fuel cells an economically appealing and clean energy source with massive market potential in portable devices, home power generation and the automotive industry. Among the more promising fuel-cell technologies are proton exchange membrane fuel cells (PEMFCs). Sliding-Mode Control of PEM Fuel Cells demonstrates the application of higher-order sliding-mode control to PEMFC dynamics. Fuel-cell dynamics are often highly nonlinear and the text shows the advantages of sliding modes in terms of robustness to external disturbance, modelling error and system-parametric disturbance using higher-order control to reduce chattering. Divided into two parts, the book first introduces the theory of fuel cells and sliding-mode control. It begins by contextualising PEMFCs both in terms of their development and within the hydrogen economy and today’s energy production situation as a whole. The reader is then guided through a discussion of fuel-cell operation pr...

  13. Magnetic Control of Locked Modes in Present Devices and ITER

    Science.gov (United States)

    Volpe, F. A.; Sabbagh, S.; Sweeney, R.; Hender, T.; Kirk, A.; La Haye, R. J.; Strait, E. J.; Ding, Y. H.; Rao, B.; Fietz, S.; Maraschek, M.; Frassinetti, L.; in, Y.; Jeon, Y.; Sakakihara, S.

    2014-10-01

    The toroidal phase of non-rotating (``locked'') neoclassical tearing modes was controlled in several devices by means of applied magnetic perturbations. Evidence is presented from various tokamaks (ASDEX Upgrade, DIII-D, JET, J-TEXT, KSTAR), spherical tori (MAST, NSTX) and a reversed field pinch (EXTRAP-T2R). Furthermore, the phase of interchange modes was controlled in the LHD helical device. These results share a common interpretation in terms of torques acting on the mode. Based on this interpretation, it is predicted that control-coil currents will be sufficient to control the phase of locking in ITER. This will be possible both with the internal coils and with the external error-field-correction coils, and might have promising consequences for disruption avoidance (by aiding the electron cyclotron current drive stabilization of locked modes), as well as for spatially distributing heat loads during disruptions. This work was supported in part by the US Department of Energy under DE-SC0008520, DE-FC-02-04ER54698 and DE-AC02-09CH11466.

  14. Robust control of uncertain time delay system: a novel sliding mode control design via LMI

    Institute of Scientific and Technical Information of China (English)

    Qu Shaocheng; Wang Yongji

    2006-01-01

    The sliding mode control problem (SMC) is studied for a class of uncertain delay system in the presence of both parameter uncertainties and external disturbances. A novel virtual feedback control method is presented. Based on Lyapunov theory, sufficient conditions for design of the robust sliding mode plane are derived. Sliding mode controller based on reaching law concept is developed, which is to ensure system trajectories from any initial conditions asymptotically convergent to sliding mode plane. The global asymptotically stability of the closed-loop system is guaranteed. A numerical example with simulation results is given to illustrate the effectiveness of the methodology.

  15. A Formal Verification Methodology for DDD Mode Pacemaker Control Programs

    Directory of Open Access Journals (Sweden)

    Sana Shuja

    2015-01-01

    Full Text Available Pacemakers are safety-critical devices whose faulty behaviors can cause harm or even death. Often these faulty behaviors are caused due to bugs in programs used for digital control of pacemakers. We present a formal verification methodology that can be used to check the correctness of object code programs that implement the safety-critical control functions of DDD mode pacemakers. Our methodology is based on the theory of Well-Founded Equivalence Bisimulation (WEB refinement, where both formal specifications and implementation are treated as transition systems. We develop a simple and general formal specification for DDD mode pacemakers. We also develop correctness proof obligations that can be applied to validate object code programs used for pacemaker control. Using our methodology, we were able to verify a control program with millions of transitions against the simple specification with only 10 transitions. Our method also found several bugs during the verification process.

  16. A Study on Mode Confusions in Adaptive Cruise Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Dae Ryong; Yang, Ji Hyun; Lee, Sang Hun [Kookmin University, Seoul (Korea, Republic of)

    2015-05-15

    Recent development in science and technology has enabled vehicles to be equipped with advanced autonomous functions. ADAS (Advanced Driver Assistance Systems) are examples of such advanced autonomous systems added. Advanced systems have several operational modes and it has been observed that drivers could be unaware of the mode they are in during vehicle operation, which can be a contributing factor of traffic accidents. In this study, possible mode confusions in a simulated environment when vehicles are equipped with an adaptive cruise control system were investigated. The mental model of the system was designed and verified using the formal analysis method. Then, the user interface was designed on the basis of those of the current cruise control systems. A set of human-in-loop experiments was conducted to observe possible mode confusions and redesign the user interface to reduce them. In conclusion, the clarity and transparency of the user interface was proved to be as important as the correctness and compactness of the mental model when reducing mode confusions.

  17. Adaptive second-order sliding mode control with uncertainty compensation

    Science.gov (United States)

    Bartolini, G.; Levant, A.; Pisano, A.; Usai, E.

    2016-09-01

    This paper endows the second-order sliding mode control (2-SMC) approach with additional capabilities of learning and control adaptation. We present a 2-SMC scheme that estimates and compensates for the uncertainties affecting the system dynamics. It also adjusts the discontinuous control effort online, so that it can be reduced to arbitrarily small values. The proposed scheme is particularly useful when the available information regarding the uncertainties is conservative, and the classical `fixed-gain' SMC would inevitably lead to largely oversized discontinuous control effort. Benefits from the viewpoint of chattering reduction are obtained, as confirmed by computer simulations.

  18. A distributed implementation of a mode switching control program

    DEFF Research Database (Denmark)

    Holdgaard, Michael; Eriksen, Thomas Juul; Ravn, Anders P.;

    1995-01-01

    A distributed implementation of a mode switched control program for a robot is described. The design of the control program is given by a set of real-time automatons. One of them plans a schedule for switching between a fixed set of control functions, another dispatches the control functions...... according to the schedule, and a final one monitors the system for exceptions that shall lead to a halt. The implementation uses four transputers with a distribution of phases of the automatons over the individual processors. The main technical result of the paper is calculations that illustrate how...

  19. Sliding Mode Control Strategy for Wind Turbine Power Maximization

    Directory of Open Access Journals (Sweden)

    Oscar Barambones

    2012-07-01

    Full Text Available The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, a sliding mode control for variable speed wind turbine that incorporates a doubly fed induction generator is described. The electrical system incorporates a wound rotor induction machine with back-to-back three phase power converter bridges between its rotor and the grid. In the presented design the so-called vector control theory is applied, in order to simplify the electrical equations. The proposed control scheme uses stator flux-oriented vector control for the rotor side converter bridge control and grid voltage vector control for the grid side converter bridge control. The stability analysis of the proposed sliding mode controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand, that the proposed controller provides high-performance dynamic characteristics, and on the other hand, that this scheme is robust with respect to the uncertainties that usually appear in the real systems.

  20. Beyond the intelligent-shell concept. The clean-mode-control for tearing perturbations

    International Nuclear Information System (INIS)

    The Intelligent Shell scheme, where a grid of active coils counteracts in a feedback scheme the measurements provided by an identical grid of sensors, has shown some limitations in the control of the dynamo tearing modes in RFX-mod. The origin of the problem is the aliasing on the measurements coming from the high periodicity sideband harmonics produced by the discrete nature of the active coils. A more efficient feedback on tearing modes is obtained by removing the sidebands from the measurements, thereby counteracting the true tearing Fourier modes. In this scheme, named Clean-Mode-Control, the sidebands are computed in real time from the coils currents using the cylindrical geometry approximation. The Clean-Mode-Control significantly alleviates the wall-locking of tearing modes in RFX-mod, giving the possibility of operating at a plasma current (1.5 MA) never reached before in a RFP machine. These features are well explained by a MHD model describing the tearing mode dynamic under the viscous torque due to the fluid motion and the electromagnetic torques produced by the feedback, the conductive structures surrounding the plasma and the non-linear interaction between the different modes. Here some new results obtained with this model are discussed. In particular we will show that the edge radial field control improves by reducing the ratio between the delay introduced by the digital acquisition of the measurements and the time constant of the shell that contains the plasma. In this formulation the active coils are assumed to be located outside the shell. (author)

  1. Taming random lasers through active spatial control of the pump.

    Science.gov (United States)

    Bachelard, N; Andreasen, J; Gigan, S; Sebbah, P

    2012-07-20

    Active control of the spatial pump profile is proposed to exercise control over random laser emission. We demonstrate numerically the selection of any desired lasing mode from the emission spectrum. An iterative optimization method is employed, first in the regime of strong scattering where modes are spatially localized and can be easily selected using local pumping. Remarkably, this method works efficiently even in the weakly scattering regime, where strong spatial overlap of the modes precludes spatial selectivity. A complex optimized pump profile is found, which selects the desired lasing mode at the expense of others, thus demonstrating the potential of pump shaping for robust and controllable single mode operation of a random laser.

  2. Backstepping design of missile guidance and control based on adaptive fuzzy sliding mode control

    OpenAIRE

    Ran Maopeng; Wang Qing; Hou Delong; Dong Chaoyang

    2014-01-01

    This paper presents an integrated missile guidance and control law based on adaptive fuzzy sliding mode control. The integrated model is formulated as a block-strict-feedback nonlinear system, in which modeling errors, unmodeled nonlinearities, target maneuvers, etc. are viewed as unknown uncertainties. The adaptive nonlinear control law is designed based on backstepping and sliding mode control techniques. An adaptive fuzzy system is adopted to approximate the coupling nonlinear functions of...

  3. Control of resistive wall modes near the ideal limit using modular internal coils

    International Nuclear Information System (INIS)

    Full text: We report on the first demonstration of active feedback stabilization of RWM near the ideal limit using a mode control algorithm implemented with a digital control system. Stabilization of resistive wall modes (RWMs) is a key issue for future tokamak reactors. An economic fusion reactor based on advanced tokamak scenarios relies on the ability to stabilize these modes up to beta values near the ideal wall limit. The 3D electromagnetic code VALEN has been extended to include important effects such as plasma mode rotation, multiple plasma modes, and realistic feedback systems that have noise and latency. Recent work on applying the concepts of observability and controllability from modern control theory to the RWM stabilization problem is described. The effectiveness of a RWM feedback system can be quantified in terms of a few coupling parameters that can be calculated using the VALEN code. Operation near the ideal wall limit implies the use of control coils internal to the main conducting structures, typically the vacuum vessel. For ITER and any future fusion tokamak power plants, it is beneficial to make these internal coils as few and small as possible. Side band excitation, lack of mode rigidity and other effects will limit how sparse the coverage can be made without compromising the ability to feedback stabilize RWMs. We present plans to address these issues in the HBT-EP device in the near future. (author)

  4. Advances and applications in sliding mode control systems

    CERN Document Server

    Zhu, Quanmin

    2015-01-01

    This book describes the advances and applications in Sliding mode control (SMC) which is widely used as a powerful method to tackle uncertain nonlinear systems. The book is organized into 21 chapters which have been organised by the editors to reflect the various themes of sliding mode control. The book provides the reader with a broad range of material from first principles up to the current state of the art in the area of SMC and observation presented in a clear, matter-of-fact style. As such it is appropriate for graduate students with a basic knowledge of classical control theory and some knowledge of state-space methods and nonlinear systems. The resulting design procedures are emphasized using Matlab/Simulink software.    

  5. Optical Mode Control by Geometric Phase in Quasicrystal Metasurface

    Science.gov (United States)

    Yulevich, Igor; Maguid, Elhanan; Shitrit, Nir; Veksler, Dekel; Kleiner, Vladimir; Hasman, Erez

    2015-11-01

    We report on the observation of optical spin-controlled modes from a quasicrystalline metasurface as a result of an aperiodic geometric phase induced by anisotropic subwavelength structure. When geometric phase defects are introduced in the aperiodic structured surface, the modes exhibit polarization helicity dependence resulting in the optical spin-Hall effect. The radiative thermal dispersion bands from a quasicrystal structure are studied where the observed bands arise from the optical spin-orbit interaction induced by the aperiodic space-variant orientations of anisotropic antennas. The optical spin-flip behavior of the revealed modes that arise from the geometric phase pickup is experimentally observed within the visible spectrum by measuring the spin-projected diffraction patterns. The introduced ability to manipulate the light-matter interaction of quasicrystals in a spin-dependent manner provides the route for molding light via spin-optical aperiodic artificial planar surfaces.

  6. Optical Mode Control by Geometric Phase in Quasicrystal Metasurface

    CERN Document Server

    Yulevich, Igor; Shitrit, Nir; Veksler, Dekel; Kleiner, Vladimir; Hasman, Erez

    2015-01-01

    We report on the observation of optical spin-controlled modes from a quasicrystalline metasurface as a result of an aperiodic geometric phase induced by anisotropic subwavelength structure. When geometric phase defects are introduced in the aperiodic structured surface, the modes exhibit polarization helicity dependence resulting in the optical spin-Hall effect. The radiative thermal dispersion bands from a quasicrystal structure were studied where the observed bands arise from the optical spin-orbit interaction induced by the aperiodic space-variant orientations of anisotropic antennas. The optical spin-flip behavior of the revealed modes that arise from the geometric phase pickup was experimentally observed within the visible spectrum by measuring the spin-projected diffraction patterns. The introduced ability to manipulate the light-matter interaction of quasicrystals in a spin-dependent manner provides the route for molding light via spin-optical aperiodic artificial planar surfaces.

  7. GA-Based Fuzzy Sliding Mode Controller for Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    W. L. Chiang

    2008-11-01

    Full Text Available Generally, the greatest difficulty encountered when designing a fuzzy sliding mode controller (FSMC or an adaptive fuzzy sliding mode controller (AFSMC capable of rapidly and efficiently controlling complex and nonlinear systems is how to select the most appropriate initial values for the parameter vector. In this paper, we describe a method of stability analysis for a GA-based reference adaptive fuzzy sliding model controller capable of handling these types of problems for a nonlinear system. First, we approximate and describe an uncertain and nonlinear plant for the tracking of a reference trajectory via a fuzzy model incorporating fuzzy logic control rules. Next, the initial values of the consequent parameter vector are decided via a genetic algorithm. After this, an adaptive fuzzy sliding model controller, designed to simultaneously stabilize and control the system, is derived. The stability of the nonlinear system is ensured by the derivation of the stability criterion based upon Lyapunov's direct method. Finally, an example, a numerical simulation, is provided to demonstrate the control methodology.

  8. Dynamic Feedback Controlling Chaos in Current-Mode Boost Converter

    Institute of Scientific and Technical Information of China (English)

    LU Wei-Guo; ZHOU Luo-Wei; LUO Quan-Ming

    2007-01-01

    A method for the control of chaos in the current-mode boost converter is presented by using the first-order dynamic feedback control. The feedback part consists of a resistance and a capacitance in series. The system to be controlled is treated as a third-order model, and then the discrete mapping model is obtained by using the data-sampling method. By analysing the position of the maximum norm eigenvalue, the stable range of feedback gain is ascertained out and its optimization is also carried out. Finally, the results of simulation and experiment confirm the correctness of the theoretical analysis and the validity of the proposed means.

  9. Sliding mode control based guidance law with impact angle constraint

    Institute of Scientific and Technical Information of China (English)

    Zhao Yao; Sheng Yongzhi; Liu Xiangdong

    2014-01-01

    The terminal guidance problem for an unpowered lifting reentry vehicle against a sta-tionary target is considered. In addition to attacking the target with high accuracy, the vehicle is also expected to achieve a desired impact angle. In this paper, a sliding mode control (SMC)-based guidance law is developed to satisfy the terminal angle constraint. Firstly, a specific sliding mode function is designed, and the terminal requirements can be achieved by enforcing both the sliding mode function and its derivative to zero at the end of the flight. Then, a backstepping approach is used to ensure the finite-time reaching phase of the sliding mode and the analytic expression of the control effort can be obtained. The trajectories generated by this method only depend on the initial and terminal conditions of the terminal phase and the instantaneous states of the vehicle. In order to test the performance of the proposed guidance law in practical application, numerical simulations are carried out by taking all the aerodynamic parameters into consideration. The effec-tiveness of the proposed guidance law is verified by the simulation results in various scenarios.

  10. Position Control of Synchronous Motor Drive by Modified Adaptive Two-phase Sliding Mode Controller

    Institute of Scientific and Technical Information of China (English)

    Mohamed Said Sayed Ahmed; Ping Zhang; Yun-Jie Wu

    2008-01-01

    A modified adaptive two-phase sliding mode controller for the synchronous motor drive that is highly robust to uncertain-ties and external disturbances is proposed in this paper. The proposed controller uses two-phase sliding mode control (SMC) where the 1st phase mainly controls the system in steady states and disturbed states-it is a smoothing phase. The 2nd phase is used mainly in the case of disturbed states. Also, it is an autotuning phase and uses a simple adaptive algorithm to tune the gain of conventional variable structure control (VSC). The modified controller is useful in position control of a permanent magnet synchronous drive.

  11. Fault tolerant control schemes using integral sliding modes

    CERN Document Server

    Hamayun, Mirza Tariq; Alwi, Halim

    2016-01-01

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

  12. Adaptive backstepping slide mode control of pneumatic position servo system

    Science.gov (United States)

    Ren, Haipeng; Fan, Juntao

    2016-06-01

    With the price decreasing of the pneumatic proportional valve and the high performance micro controller, the simple structure and high tracking performance pneumatic servo system demonstrates more application potential in many fields. However, most existing control methods with high tracking performance need to know the model information and to use pressure sensor. This limits the application of the pneumatic servo system. An adaptive backstepping slide mode control method is proposed for pneumatic position servo system. The proposed method designs adaptive slide mode controller using backstepping design technique. The controller parameter adaptive law is derived from Lyapunov analysis to guarantee the stability of the system. A theorem is testified to show that the state of closed-loop system is uniformly bounded, and the closed-loop system is stable. The advantages of the proposed method include that system dynamic model parameters are not required for the controller design, uncertain parameters bounds are not need, and the bulk and expensive pressure sensor is not needed as well. Experimental results show that the designed controller can achieve better tracking performance, as compared with some existing methods.

  13. Global Mode-Based Control of Supersonic Jet Noise

    Science.gov (United States)

    Natarajan, Mahesh; Freund, Jonathan; Bodony, Daniel

    2015-11-01

    The loudest source of high-speed jet noise appears to be describable by unsteady wavepackets that resemble instabilities. We seek to reduce their acoustic impact by developing a novel control strategy that uses global modes to model their dynamics and structural sensitivity of the linearized compressible Navier-Stokes operator to determine effective linear feedback control. Using co-located actuators and sensors we demonstrate the method on an axisymmetric Mach 1.5 fitted with a nozzle. Direct numerical simulations using this control show significant noise reduction, with additional reduction with increase in control gain. Eigenanalysis of the uncontrolled and controlled mean flows reveal fundamental changes in the spectrum at frequencies lower than that used by the control. The non-normality of the global modes is shown to enable this control to affect a wide range of frequencies. The low-frequency wavepacket components are made less acoustically efficient, which is reflected in the far-field noise spectrum. Mean flow alterations are minor near the nozzle and only become apparent further downstream. Office of Naval Research and National Science Foundation.

  14. Recent advances in sliding modes from control to intelligent mechatronics

    CERN Document Server

    Efe, Mehmet

    2015-01-01

    This volume is dedicated to Professor Okyay Kaynak to commemorate his life time impactful research and scholarly achievements and outstanding services to profession. The 21 invited chapters have been written by leading researchers who, in the past, have had association with Professor Kaynak as either his students and associates or colleagues and collaborators. The focal theme of the volume is the Sliding Modes covering a broad scope of topics from theoretical investigations to their significant applications from Control to Intelligent Mechatronics.  

  15. Stability notions and Lyapunov functions for sliding mode control systems

    OpenAIRE

    Polyakov, Andrey; Fridman, Leonid

    2014-01-01

    The paper surveys mathematical tools required for stability and convergence analysis of modern sliding mode control systems. Elements of Filippov theory of differential equations with discontinuous right-hand sides and its recent extensions are discussed. Stability notions (from Lyapunov stability (1982) to fixed-time stability (2012)) are observed. Concepts of generalized derivatives and non-smooth Lyapunov functions are considered. The generalized Lyapunov theorems for stability analysis an...

  16. A high performance switching audio amplifier using sliding mode control

    OpenAIRE

    Pillonnet, Gael; Cellier, Rémy; Abouchi, Nacer; Chiollaz, Monique

    2008-01-01

    International audience The switching audio amplifiers are widely used in various portable and consumer electronics due to their high efficiency, but suffers from low audio performances due to inherent nonlinearity. This paper presents an integrated class D audio amplifier with low consumption and high audio performances. It includes a power stage and an efficient control based on sliding mode technique. This monolithic class D amplifier is capable of delivering up to 1W into 8Ω load at les...

  17. Modified robust sliding-mode control method for wafer scanner

    Directory of Open Access Journals (Sweden)

    Yiguang Wang

    2015-03-01

    Full Text Available This article studies the precision motion control of a long-stroke reticle stage driven by the permanent magnet linear motor in wafer scanner. A robust sliding-mode control method is proposed for tracking the reference trajectory in the presence of un-modeled dynamics, parametric uncertainty and external disturbances including force ripple, cogging and friction in the controlled system. A modified sliding-mode term based on the variable structure technique for eliminating the tracking error is employed in the proposed control law. The system stability and tracking convergence of the closed-loop control system are guaranteed by Lyapunov theory theoretically. The feasibility and effectiveness of the proposed method are demonstrated by comparative experiments on a linear motion testbed. The experimental results show that better tracking performance can be achieved by the proposed method compared with the conventional proportional–integral–derivative method and it can be considered as a possible alternative in the precision motion control system.

  18. Sliding mode control of electromagnetic tethered satellite formation

    Science.gov (United States)

    Hallaj, Mohammad Amin Alandi; Assadian, Nima

    2016-08-01

    This paper investigates the control of tethered satellite formation actuated by electromagnetic dipoles and reaction wheels using the robust sliding mode control technique. Generating electromagnetic forces and moments by electric current coils provides an attractive control actuation alternative for tethered satellite system due to the advantages of no propellant consumption and no obligatory rotational motion. Based on a dumbbell model of tethered satellite in which the flexibility and mass of the tether is neglected, the equations of motion in Cartesian coordinate are derived. In this model, the J2 perturbation is taken into account. The far-field and mid-field models of electromagnetic forces and moments of two satellites on each other and the effect of the Earth's magnetic field are presented. A robust sliding mode controller is designed for precise trajectory tracking purposes and to deal with the electromagnetic force and moment uncertainties and external disturbances due to the Earth's gravitational and magnetic fields inaccuracy. Numerical simulation results are presented to validate the effectiveness of the developed controller and its superiority over the linear controller.

  19. Mode Adaptive Droop Control with Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

    DEFF Research Database (Denmark)

    Kim, Jaehong; Guerrero, Josep M.; Rodriguez, Pedro;

    2011-01-01

    in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation...

  20. A Riding-through Technique for Seamless Transition between Islanded and Grid-Connected Modes of Droop-Controlled Inverters

    DEFF Research Database (Denmark)

    Hu, Shang-hung; Lee, Tzung-Lin; Kuo, Chun-Yi;

    2016-01-01

    This paper presents a seamless transition method for a droop-controlled inverter. The droop control is suitable to make the inverter work as a voltage source in both islanded and grid-connected modes, however, the transfer between theses modes can result in a big inrush current that may damage...... the system. The proposed method allows the droop-controlled inverter to improve the transient response when transferring between modes, by detecting the inrush current, activating a current control loop during transients, and then transferring back to droop-controlled mode smoothly by using a virtual...... inductance loop. In addition, a local phase-locked-loop (PLL) is proposed to align the inverter voltage with the grid in order to reduce the transient current during the transition. Therefore, the droop-controlled inverter is able to operate in both grid-connected and islanded modes, providing as well...

  1. Feedback control of resistive wall modes in toroidal devices

    International Nuclear Information System (INIS)

    Feedback of nonaxisymmetric resistive wall modes (RWM) is studied analytically for cylindrical plasmas and computationally for high beta tokamaks. Internal poloidal sensors give superior performance to radial sensors, and this is explained by the distribution of poles and residues for the transfer functions. A single poloidal array of feedback coils allows robust control with respect to variations in plasma pressure, current and rotation velocity. The control analysis is applied to advanced scenarios for ITER. Studies are also shown of configurations with multiple poloidal coils and of feedback systems for nonresonant MHD instabilities in reversed field pinches. (author)

  2. Adaptive Fractional Fuzzy Sliding Mode Control for Multivariable Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Junhai Luo

    2014-01-01

    Full Text Available This paper presents a robust adaptive fuzzy sliding mode control method for a class of uncertain nonlinear systems. The fractional order calculus is employed in the parameter updating stage. The underlying stability analysis as well as parameter update law design is carried out by Lyapunov based technique. In the simulation, two examples including a comparison with the traditional integer order counterpart are given to show the effectiveness of the proposed method. The main contribution of this paper consists in the control performance is better for the fractional order updating law than that of traditional integer order.

  3. Observer Based Sliding Mode Attitude Control: Theoretical and Experimental Results

    Directory of Open Access Journals (Sweden)

    U. Jørgensen

    2011-07-01

    Full Text Available In this paper we present the design of a sliding mode controller for attitude control of spacecraft actuated by three orthogonal reaction wheels. The equilibrium of the closed loop system is proved to be asymptotically stable in the sense of Lyapunov. Due to cases where spacecraft do not have angular velocity measurements, an estimator for the generalized velocity is derived and asymptotic stability is proven for the observer. The approach is tested on an experimental platform with a sphere shaped Autonomous Underwater Vehicle SATellite: AUVSAT, developed at the Norwegian University of Science and Technology.

  4. [Intravesical active prostate bleeding diagnosed in B-mode ultrasound].

    Science.gov (United States)

    Kirchgesner, T; Danse, E; Tombal, B

    2013-09-01

    Hematuria is one of the most frequent minor complications after prostatic biopsy. We would like to report the case of a 68-year-old patient with massive hematuria after prostatic biopsy and intravesical active prostate bleeding diagnosed in B-mode ultrasonography. PMID:24034804

  5. Electric sail control mode for amplified transverse thrust

    CERN Document Server

    Toivanen, Petri; Envall, Jouni

    2014-01-01

    The electric solar wind sail produces thrust by centrifugally spanned high voltage tethers interacting with the solar wind protons. The sail attitude can be controlled and attitude maneuvers are possible by tether voltage modulation synchronous with the sail rotation. Especially, the sail can be inclined with respect to the solar wind direction to obtain transverse thrust to change the osculating orbit angular momentum. Such an inclination has to be maintained by a continual control voltage modulation. Consequently, the tether voltage available for the thrust is less than the maximum voltage provided by the power system. Using a spherical pendulum as a model for a single rotating tether, we derive analytical estimations for the control efficiency for two separate sail control modes. One is a continuous control modulation that corresponds to strictly planar tether tip motion. The other is an on-off modulation with the tether tip moving along a closed loop on a saddle surface. The novel on-off mode is introduce...

  6. Herbicide activity of monosulfuron and its mode of action.

    Science.gov (United States)

    Fan, Zhi-Jin; Ai, Ying-Wei; Qian, Chuan-Fan; Li, Zheng-Ming

    2005-01-01

    Monosulfuron was developed for weed control in the field of wheat (Triticum, aestivum L.) and millet (Panicum miliaceum L.) with the application rate ranging from 15 to 60 g ai/hm2. Herbicidal activity of monosulfuron was evaluated systematically by bioassay using maize (Zea mays L.) taproot as indicator and weed fresh weight of Acalypha australis L. and Echinochloa phyllopogon. Maize CAU 3138 was the most tolerant cultivars to monosulfuron with IC50 (concentration of 50% inhibition) of 85 microg/kg, Yedan 13 was one of the most sensitive cultivars to monosulfuron with IC50 of 6.4 microg/kg. Monosulfuron inhibited the growth of Acalypha australis L. strongly comparing with that of Echinochloa phyllopogon. Monosulfuron was a good acetolactate synthase (ALS) inhibitor in vitro, the I50 (50% of inhibition) of monosulfuron, chlorsulfuron, tribenuron-methyl and nicosulfuron for CAU 3138 were 32, 2, 19 and 26 nmol/L respectively, for Yedan 13 the I50 were 15, 3, 17 and 65 nmol/L respectively. In vivo ALS inhibition occurred only in higher concentration of 4 sulfonylurea herbicide tested. Comparison study of this test indicated that the mode of action of monosulfuron was the same as that of other sulfonylurea herbicides such as chlorsulfuron, tribenuron-methyl and nicosulfuron, they were all inhibitors targeted at the ALS. PMID:16083111

  7. Herbicide activity of monosulfuron and its mode of action

    Institute of Scientific and Technical Information of China (English)

    FAN Zhi-jin; AI Ying-wei; QIAN Chuan-fan; LI Zheng-ming

    2005-01-01

    Monosulfuron was developed for weed control in the field of wheat( Triticum, aestivum L. ) and millet( Panicum miliaceum L. )with the application rate ranging from 15 to 60 g ai/hm2 . Herbicidal activity of monosulfuron was evaluated systematically by bioassay using maize( Zea mays L. ) taproot as indicator and weed fresh weight of Acalypha australis L. and Echinochloa phyllopogon. Maize CAU 3138was the most tolerant cultivars to monosulfuron with IC50 (concentration of 50% inhibition) of 85 μg/kg, Yedan 13 was one of the most sensitive cultivars to monosulfuron with IC50 of 6.4 μg/kg. Monosulfuron inhibited the growth of Acalypha australis L. strongly comparing with that of Echinochloa phyllopogon. Monosulfuron was a good acetolactate synthase(ALS) inhibitor in vitro, the/50 (50% of inhibition) of monosulfuron, chlorsulfuron, tribenuron-methyl and nicosulfuron for CAU 3138 were 32, 2, 19 and 26 nmol/L respectively, for Yedan 13 the /50 were 15, 3, 17 and 65 nmol/L respectively. In vivo ALS inhibition occurred only in higher concentration of 4 sulfonylurea herbicide tested. Comparison study of this test indicated that the mode of action of monosulfuron was the same as that of other sulfonylurea herbicides such as chlorsulfuron, tribenuron-methyl and nicosulfuron, they were all inhibitors targeted at the ALS.

  8. Multi-dimension Aspiration Control Mode in Phacoemulsification

    Institute of Scientific and Technical Information of China (English)

    Xiangqun Wang; Mingguang He; Junwen Zeng

    2005-01-01

    Purpose: Multi-dimension aspiration control mode was put forward in this study.Accuracy of multi-dimension aspiration control model was compared to simple traditional pedal control model.Methods: Induced by high aspiration pressure (200~250 mmHg), hard nucleus (≥Grade Ⅲ ) of senile cataract was chopped before phacoemulsification in 170 patients (174 eyes). Ninety-one patients (94 eyes) accepted multi-dimension aspiration control model in which aspiration direction, distance and targets prevention were adjusted by phaco-tip besides traditional pedal control. Another 79 patients (80 eyes) were compared as reviewed group, aspiration of which was controlled simply by traditional pedal control. Postcapsular rupture rates (PCRR) were compared between two groups.Results: Multi-dimension control model could make the terminal effects cooperate with phacoemulsification more precisely and protect post capsular from damage (x2 =5.41, P < 0.02).Conclusion: Multi-dimension control model could improve the accuracy of aspiration effects and protect postcapsular from damage.

  9. Controllable damping of high-Q violin modes in fused silica suspension fibers

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriev, A V; Mescheriakov, S D; Mitrofanov, V P [Faculty of Physics, Moscow State University, Moscow 119991 (Russian Federation); Tokmakov, K V, E-mail: dmitriev@hbar.phys.msu.r, E-mail: mitr@hbar.phys.msu.r [Present address: Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2010-01-21

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 10{sup 8}. They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  10. Hybrid Fuzzy Sliding Mode Control of a DFIG Integrated into the Network

    Directory of Open Access Journals (Sweden)

    Belabbas Belkacem

    2013-12-01

    Full Text Available This paper presents the study of a variable speed wind energy conversion system using a Doubly Fed Induction Generator (DFIG based on a Fuzzy sliding mode control (FSMC applied to achieve control of active and reactive powers exchanged between the stator of the DFIG and the grid to ensure a Maximum Power Point Tracking (MPPT of a wind energy conversion system. However the principal drawback of the sliding mode, is the chattering effect which characterized by torque ripple, this phenomena is undesirable and harmful for the machines, it generates noises and additional forces of torsion on the machine shaft. In order to reduce the chattering effect, the Sign function of sliding mode controller’s discontinuous part is replaced by a fuzzy logic; we will have the fuzzy sliding mode controller (FSMC. The FSMC makes it possible to combine the performances of the two types of controllers (SMC and FLC and eliminates the chattering effect. The proposed control algorithm is applied to a DFIG where the stator is directly connected to the grid and the rotor is connected to a three-level converter structure NPC to suppress low level harmonics, higher frequencies will be filtered out by the machine. Second goal of this paper is to extract a maximum of power; the rotor side converter is controlled by using a stator flux-oriented strategy. The decoupling created by the control between active and reactive stator power allows keeping the power factor close to unity. Simulation results show that the wind turbine can operate at its optimum energy for a wide range of wind speed. Both simulation and validation results show effectiveness of the proposed control strategy is in terms of power regulation. Moreover, the fuzzy sliding mode approach is arranged so as to reduce the chattering produced in the generated power that could lead to increased mechanical stress because of strong torque variations.

  11. Integral Sliding Mode Control Design for Electronic Throttle Valve System

    Directory of Open Access Journals (Sweden)

    Shibly Ahmed AL-Samarraie

    2015-09-01

    Full Text Available One of the major components in an automobile engine is the throttle valve part. It is used to keep up with emissions and fuel efficiency low. Design a control system to the throttle valve is newly common requirement trend in automotive technology. The non-smoothness nonlinearity in throttle valve model are due to the friction model and the nonlinear spring, the uncertainty in system parameters and non-satisfying the matching condition are the main obstacles when designing a throttle plate controller. In this work, the theory of the Integral Sliding Mode Control (ISMC is utilized to design a robust controller for the Electronic Throttle Valve (ETV system. From the first instant, the electronic throttle valve dynamics is represented by the nominal system model, this model is not affected by system parameters uncertainty and the non-smooth nonlinearities. This is a consequence of applying the integral sliding mode control. The ISMC consists of two part; the first is the nominal control which is used to control the nominal system, while the second is a discontinuous part which is used to eliminate the effects of the parameters uncertainty and the non-smooth nonlinearities from system model. These features for the ISMC are proved mathematically and demonstrated numerically via seven numerical simulations and for different desired trajectories. The simulation results clarify that for different system parameters, the ETV behaves as a nominal system. This enables to freely and precisely select the system response characteristics and the time required for the throttle angle to reach the desired value. Moreover the ability to deal with the chattering problem is demonstrated through the worked simulation tests, where the chattering is eliminated via approximating the signum function by arc tan function.

  12. Backstepping design of missile guidance and control based on adaptive fuzzy sliding mode control

    Directory of Open Access Journals (Sweden)

    Ran Maopeng

    2014-06-01

    Full Text Available This paper presents an integrated missile guidance and control law based on adaptive fuzzy sliding mode control. The integrated model is formulated as a block-strict-feedback nonlinear system, in which modeling errors, unmodeled nonlinearities, target maneuvers, etc. are viewed as unknown uncertainties. The adaptive nonlinear control law is designed based on backstepping and sliding mode control techniques. An adaptive fuzzy system is adopted to approximate the coupling nonlinear functions of the system, and for the uncertainties, we utilize an online-adaptive control law to estimate the unknown parameters. The stability analysis of the closed-loop system is also conducted. Simulation results show that, with the application of the adaptive fuzzy sliding mode control, small miss distances and smooth missile trajectories are achieved, and the system is robust against system uncertainties and external disturbances.

  13. Backstepping design of missile guidance and control based on adaptive fuzzy sliding mode control

    Institute of Scientific and Technical Information of China (English)

    Ran Maopeng; Wang Qing; Hou Delong; Dong Chaoyang

    2014-01-01

    This paper presents an integrated missile guidance and control law based on adaptive fuzzy sliding mode control. The integrated model is formulated as a block-strict-feedback nonlinear system, in which modeling errors, unmodeled nonlinearities, target maneuvers, etc. are viewed as unknown uncertainties. The adaptive nonlinear control law is designed based on backstepping and sliding mode control techniques. An adaptive fuzzy system is adopted to approximate the coupling nonlinear functions of the system, and for the uncertainties, we utilize an online-adaptive control law to estimate the unknown parameters. The stability analysis of the closed-loop system is also conducted. Simulation results show that, with the application of the adaptive fuzzy sliding mode control, small miss distances and smooth missile trajectories are achieved, and the system is robust against system uncertainties and external disturbances.

  14. Taming random lasers through active spatial control of the pump

    CERN Document Server

    Bachelard, Nicolas; Gigan, Sylvain; Sebbah, Patrick

    2012-01-01

    Active control of the pump spatial profile is proposed to exercise control over random laser emission. We demonstrate numerically the selection of any desired lasing mode from the emission spectrum. An iterative optimization method is employed, first in the regime of strong scattering where modes are spatially localized and can be easily selected using local pumping. Remarkably, this method works efficiently even in the weakly scattering regime, where strong spatial overlap of the modes precludes spatial selectivity. A complex optimized pump profile is found, which selects the desired lasing mode at the expense of others, thus demonstrating the potential of pump shaping for robust and controllable singlemode operation of a random laser.

  15. Activity modes selection for project crashing through deterministic simulation

    Directory of Open Access Journals (Sweden)

    Ashok Mohanty

    2011-12-01

    Full Text Available Purpose: The time-cost trade-off problem addressed by CPM-based analytical approaches, assume unlimited resources and the existence of a continuous time-cost function. However, given the discrete nature of most resources, the activities can often be crashed only stepwise. Activity crashing for discrete time-cost function is also known as the activity modes selection problem in the project management. This problem is known to be NP-hard. Sophisticated optimization techniques such as Dynamic Programming, Integer Programming, Genetic Algorithm, Ant Colony Optimization have been used for finding efficient solution to activity modes selection problem. The paper presents a simple method that can provide efficient solution to activity modes selection problem for project crashing.Design/methodology/approach: Simulation based method implemented on electronic spreadsheet to determine activity modes for project crashing. The method is illustrated with the help of an example.Findings: The paper shows that a simple approach based on simple heuristic and deterministic simulation can give good result comparable to sophisticated optimization techniques.Research limitations/implications: The simulation based crashing method presented in this paper is developed to return satisfactory solutions but not necessarily an optimal solution.Practical implications: The use of spreadsheets for solving the Management Science and Operations Research problems make the techniques more accessible to practitioners. Spreadsheets provide a natural interface for model building, are easy to use in terms of inputs, solutions and report generation, and allow users to perform what-if analysis.Originality/value: The paper presents the application of simulation implemented on a spreadsheet to determine efficient solution to discrete time cost tradeoff problem.

  16. Robust Sliding Mode Fuzzy Control of a Car Suspension System

    Directory of Open Access Journals (Sweden)

    Ayman A. Aly

    2013-07-01

    Full Text Available Different characteristics can be considered in a suspension system design like: ride comfort, body travel, road handling and suspension travel. No suspension system can optimize all these parameters together but a better tradeoff among these parameters can be achieved in active suspension system.Objective of this paper is to establish a robust control technique of the active suspension system for a quarter-car model. The paper describes also the model and controller used in the study and discusses the vehicle response results obtained from a range of road input simulations. A comparison of robust suspension sliding fuzzy control and passive control is shown using MATLAB simulations.

  17. Hybrid Fuzzy Sliding Mode Controller for Timedelay System

    Directory of Open Access Journals (Sweden)

    N. K. Yadav

    2013-07-01

    Full Text Available This paper is concerned with the problems of stability analysis and stabilization control design for a class of discrete-time T-S fuzzy systems with state-delay for multi-input and multi-output. The nonlinear fuzzy controller helps to overcome the problems of the ill - defined model of the systems, which are creating the undesirable performance. . Here sliding surface is being designed for error function of nonlinear system and sliding mode control is being designed here. The switching surface is being proven for its asymptotic stability. The generated error signal and change of error signal will be utilized for application heuristic knowledge to design the rule base in the fuzzy logic control and fuzzy logic controller is designed here. The proposed technique also brings in a systematic approach to the fuzzy logic control, thus overcoming lots of heuristics that were in vogue with earlier fuzzy logic applications. Fuzzy logic control has been applied to a second order model of a roll autopilot. It has been found that the proposed scheme is robust and works satisfactorily even when parameters are perturbed as much as fifteen percent of their geometric mean value. This designed algorithm will be more effective for highly unstable nonlinear systems such as aerospace system.

  18. Guided-mode resonant polarization-controlled tunable color filters.

    Science.gov (United States)

    Uddin, Mohammad Jalal; Khaleque, Tanzina; Magnusson, Robert

    2014-05-19

    We demonstrate efficient guided-mode resonant polarization-controlled tunable color filters. The devices consist of subwavelength gratings that are partially etched into a thin silicon-nitride film deposited on a glass substrate. Two color filters with grating periods of 300 nm and 370 nm are designed and fabricated. The 300-nm device exhibits green and blue colors and the 370-nm device generates red and yellow colors for TE and TM polarization, respectively. The pixels have a spectral bandwidth of ~12 nm with efficiencies exceeding 90% for TE polarization and 80% for TM polarization. The devices may find application in displays, image sensors, and biomedical imaging technologies. PMID:24921349

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

    KAUST Repository

    Siddiqui, Bilal A.

    2016-07-26

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

  20. Time delay controlled annular array transducers for omnidirectional guided wave mode control in plate like structures

    International Nuclear Information System (INIS)

    Guided waves in plate like structures offer several modes with unique characteristics that can be taken advantage for nondestructive inspection applications. Conditions relating to the structure under inspection like the surrounding media, liquid loading, coatings etc require the use of special modes for successful inspection. Therefore, transducers that can excite mode controlled guided waves are essential for defect detection and discrimination in structures. Array transducers with annular elements can generate omnidirectional guided waves in plate like structures. However, the wave modes excited are limited to a particular wavelength governed by the element spacing. This limitation on the annular array transducers can be overcome by controlling the phase at each element relative to one another. In this work, annular array transducer construction techniques are theoretically examined and the optimum phase delays between the annular elements to excite a desired guided wave mode are calculated. A five element comb type annular array transducer is fabricated utilizing 1–3 type piezocomposite material. The mode control capability of the transducer is experimentally verified by selectively exciting the A0 and S0 guided wave modes in an aluminum plate like structure. (paper)

  1. Uncertain Unified Chaotic Systems Control with Input Nonlinearity via Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Zhi-ping Shen

    2016-01-01

    Full Text Available This paper studies the stabilization problem for a class of unified chaotic systems subject to uncertainties and input nonlinearity. Based on the sliding mode control theory, we present a new method for the sliding mode controller design and the control law algorithm for such systems. In order to achieve the goal of stabilization unified chaotic systems, the presented controller can make the movement starting from any point in the state space reach the sliding mode in limited time and asymptotically reach the origin along the switching surface. Compared with the existing literature, the controller designed in this paper has many advantages, such as small chattering, good stability, and less conservative. The analysis of the motion equation and the simulation results all demonstrate that the method is effective.

  2. Robust Sliding Mode Fuzzy Control of a Car Suspension System

    OpenAIRE

    Ayman A. Aly

    2013-01-01

    Different characteristics can be considered in a suspension system design like: ride comfort, body travel, road handling and suspension travel. No suspension system can optimize all these parameters together but a better tradeoff among these parameters can be achieved in active suspension system.Objective of this paper is to establish a robust control technique of the active suspension system for a quarter-car model. The paper describes also the model and controller used in the study and dis...

  3. Direct power control of DFIG wind turbine systems based on an intelligent proportional-integral sliding mode control.

    Science.gov (United States)

    Li, Shanzhi; Wang, Haoping; Tian, Yang; Aitouch, Abdel; Klein, John

    2016-09-01

    This paper presents an intelligent proportional-integral sliding mode control (iPISMC) for direct power control of variable speed-constant frequency wind turbine system. This approach deals with optimal power production (in the maximum power point tracking sense) under several disturbance factors such as turbulent wind. This controller is made of two sub-components: (i) an intelligent proportional-integral module for online disturbance compensation and (ii) a sliding mode module for circumventing disturbance estimation errors. This iPISMC method has been tested on FAST/Simulink platform of a 5MW wind turbine system. The obtained results demonstrate that the proposed iPISMC method outperforms the classical PI and intelligent proportional-integral control (iPI) in terms of both active power and response time.

  4. Direct power control of DFIG wind turbine systems based on an intelligent proportional-integral sliding mode control.

    Science.gov (United States)

    Li, Shanzhi; Wang, Haoping; Tian, Yang; Aitouch, Abdel; Klein, John

    2016-09-01

    This paper presents an intelligent proportional-integral sliding mode control (iPISMC) for direct power control of variable speed-constant frequency wind turbine system. This approach deals with optimal power production (in the maximum power point tracking sense) under several disturbance factors such as turbulent wind. This controller is made of two sub-components: (i) an intelligent proportional-integral module for online disturbance compensation and (ii) a sliding mode module for circumventing disturbance estimation errors. This iPISMC method has been tested on FAST/Simulink platform of a 5MW wind turbine system. The obtained results demonstrate that the proposed iPISMC method outperforms the classical PI and intelligent proportional-integral control (iPI) in terms of both active power and response time. PMID:27346331

  5. Design Sliding Mode Controller with Parallel Fuzzy Inference System Compensator to Control of Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Iman Nazari

    2014-03-01

    Full Text Available Sliding mode controller (SMC is a significant nonlinear controller under condition of partly uncertain dynamic parameters of system. This controller is used to control of highly nonlinear systems especially for robot manipulators, because this controller is a robust and stable. Conversely, pure sliding mode controller is used in many applications; it has two important drawbacks namely; chattering phenomenon, and nonlinear equivalent dynamic formulation in uncertain dynamic parameter. The nonlinear equivalent dynamic formulation problem and chattering phenomenon in uncertain system can be solved by using artificial intelligence theorem. However fuzzy logic controller is used to control complicated nonlinear dynamic systems, but it cannot guarantee stability and robustness. In this research parallel fuzzy logic theory is used to compensate the system dynamic uncertainty.

  6. Design Sliding Mode Controller of with Parallel Fuzzy Inference System Compensator to Control of Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Farzin Piltan

    2013-06-01

    Full Text Available Sliding mode controller (SMC is a significant nonlinear controller under condition of partly uncertain dynamic parameters of system. This controller is used to control of highly nonlinear systems especially for robot manipulators, because this controller is a robust and stable. Conversely, pure sliding mode controller is used in many applications; it has two important drawbacks namely; chattering phenomenon, and nonlinear equivalent dynamic formulation in uncertain dynamic parameter. The nonlinear equivalent dynamic formulation problem and chattering phenomenon in uncertain system can be solved by using artificial intelligence theorem. However fuzzy logic controller is used to control complicated nonlinear dynamic systems, but it cannot guarantee stability and robustness.  In this research parallel fuzzy logic theory is used to compensate the system dynamic uncertainty.

  7. Combined Sliding Mode Control with a Feedback Linearization for Speed Control of Induction Motor

    Directory of Open Access Journals (Sweden)

    Aamir Hashim Obeid Ahmed

    2011-06-01

    Full Text Available Induction Motor (IM speed control is an area of research that has been in prominence for some time now. In this paper, a nonlinear controller is presented for IM drives. The nonlinear controller is designed based on input-output feedback linearization control technique, combined with sliding mode control (SMC to obtain a robust, fast and precise control of IM speed. The input-output feedback linearization control decouples the flux control from the speed control and makes the synthesis of linear controllers possible. To validate the performances of the proposed control scheme, we provided a series of simulation results and a comparative study between the performances of the proposed control strategy and those of the feedback linearization control (FLC schemes. Simulation results show that the proposed control strategy scheme shows better performance than the FLC strategy in the face of system parameters variation

  8. Fast control technique based on peak current mode control of the output capacitor current

    OpenAIRE

    Alou Cervera, Pedro; García Suárez, Oscar; Oliver Ramírez, Jesús Angel; Cobos Márquez, José Antonio; Viejo de Frutos, Miriam del

    2010-01-01

    The control proposed and analyzed in this paper is based on the peak current mode control of the output capacitor current of a Buck converter. The output capacitor current loop provides fast dynamic response to the control since it behaves as a feed-forward of the load current while the voltage loop provides accurate steady state regulation. A simulation oriented averaged model of the proposed control has been developed to design the external voltage loop. As shown in simulations, with the co...

  9. Adaptive Sliding Mode Control Method Based on Nonlinear Integral Sliding Surface for Agricultural Vehicle Steering Control

    Directory of Open Access Journals (Sweden)

    Taochang Li

    2014-01-01

    Full Text Available Automatic steering control is the key factor and essential condition in the realization of the automatic navigation control of agricultural vehicles. In order to get satisfactory steering control performance, an adaptive sliding mode control method based on a nonlinear integral sliding surface is proposed in this paper for agricultural vehicle steering control. First, the vehicle steering system is modeled as a second-order mathematic model; the system uncertainties and unmodeled dynamics as well as the external disturbances are regarded as the equivalent disturbances satisfying a certain boundary. Second, a transient process of the desired system response is constructed in each navigation control period. Based on the transient process, a nonlinear integral sliding surface is designed. Then the corresponding sliding mode control law is proposed to guarantee the fast response characteristics with no overshoot in the closed-loop steering control system. Meanwhile, the switching gain of sliding mode control is adaptively adjusted to alleviate the control input chattering by using the fuzzy control method. Finally, the effectiveness and the superiority of the proposed method are verified by a series of simulation and actual steering control experiments.

  10. Second order sliding mode control for a quadrotor UAV.

    Science.gov (United States)

    Zheng, En-Hui; Xiong, Jing-Jing; Luo, Ji-Liang

    2014-07-01

    A method based on second order sliding mode control (2-SMC) is proposed to design controllers for a small quadrotor UAV. For the switching sliding manifold design, the selection of the coefficients of the switching sliding manifold is in general a sophisticated issue because the coefficients are nonlinear. In this work, in order to perform the position and attitude tracking control of the quadrotor perfectly, the dynamical model of the quadrotor is divided into two subsystems, i.e., a fully actuated subsystem and an underactuated subsystem. For the former, a sliding manifold is defined by combining the position and velocity tracking errors of one state variable, i.e., the sliding manifold has two coefficients. For the latter, a sliding manifold is constructed via a linear combination of position and velocity tracking errors of two state variables, i.e., the sliding manifold has four coefficients. In order to further obtain the nonlinear coefficients of the sliding manifold, Hurwitz stability analysis is used to the solving process. In addition, the flight controllers are derived by using Lyapunov theory, which guarantees that all system state trajectories reach and stay on the sliding surfaces. Extensive simulation results are given to illustrate the effectiveness of the proposed control method.

  11. Second order sliding mode control for a quadrotor UAV.

    Science.gov (United States)

    Zheng, En-Hui; Xiong, Jing-Jing; Luo, Ji-Liang

    2014-07-01

    A method based on second order sliding mode control (2-SMC) is proposed to design controllers for a small quadrotor UAV. For the switching sliding manifold design, the selection of the coefficients of the switching sliding manifold is in general a sophisticated issue because the coefficients are nonlinear. In this work, in order to perform the position and attitude tracking control of the quadrotor perfectly, the dynamical model of the quadrotor is divided into two subsystems, i.e., a fully actuated subsystem and an underactuated subsystem. For the former, a sliding manifold is defined by combining the position and velocity tracking errors of one state variable, i.e., the sliding manifold has two coefficients. For the latter, a sliding manifold is constructed via a linear combination of position and velocity tracking errors of two state variables, i.e., the sliding manifold has four coefficients. In order to further obtain the nonlinear coefficients of the sliding manifold, Hurwitz stability analysis is used to the solving process. In addition, the flight controllers are derived by using Lyapunov theory, which guarantees that all system state trajectories reach and stay on the sliding surfaces. Extensive simulation results are given to illustrate the effectiveness of the proposed control method. PMID:24751475

  12. Efficiency in Controlling Activities

    OpenAIRE

    Van Nguyen, Tuyen

    2015-01-01

    Controlling is essential for financial success of corporations. An efficient controlling system should be implemented in order to manage financial performance from income, expense to profitability. The purpose of the thesis is to provide insight knowledge towards corporate accounting management as well as to propose potential improvement for the existing controlling system of the case company, which is Bosch Rexroth Japan. The theoretical framework creates the knowledge foundation for re...

  13. Explaining adolescents' cigarette smoking: a comparison of four modes of action control and test of the role of self-regulatory mode.

    Science.gov (United States)

    Rivis, Amanda; Sheeran, Paschal; Armitage, Christopher J

    2010-10-01

    The present study compared how well four modes of action control (intentional, habitual, reactive and stereotype activation) explain adolescents' cigarette smoking, and examined whether individual differences in self-regulation (locomotion and assessment tendencies; Higgins, Kruglanski, & Pierro, 2003) moderate the behavioural impact of the respective modes. Findings from a prospective questionnaire survey showed that (a) willingness, prototype perceptions and past behaviour--but not intention--predicted smoking behaviour, and explained 63% of the variance, and (b) the assessment mode of self-regulation moderated the past behaviour-future behaviour relation such that past behaviour had less impact on future smoking behaviour at high levels of assessment. These findings suggest that adolescents' smoking is controlled by stereotype activation, habitual and reactive processes. Implications of the results for designing effective adolescent smoking cessation programmes are considered. PMID:20204964

  14. 基于滑模控制的谐振阻抗型混合有源滤波系统控制技术%Control Technique of the Resonant Impedance Type Hybrid Active Power Filter Based on Sliding Mode Control

    Institute of Scientific and Technical Information of China (English)

    梁应昌

    2015-01-01

    基于滑模控制原理,针对矿用谐振阻抗型混合有源滤波系统( RITHAPF)控制技术进行深入研究,并对电网进行无功补偿和谐波抑制。利用开关函数建模法进行系统建模,给出RITHAPF的数学模型。通过对RITHAPF的等效模型的分析推导,提出了RITHAPF系统的收敛和稳定判据。结合离散指数趋近律对离散滑模控制的影响,将连续系统的指数趋近律方法推广到离散系统,证明离散指数趋近律滑模控制对系统摄动和外界干扰依然具有鲁棒性。进一步根据有源电力滤波器的离散数学模型,设计滑模离散数学模型。基于趋近律离散滑模变结构控制设计有源部分的电流跟踪控制器。结果表明,采用滑模控制的谐振阻抗型混合有源滤波器对矿用直流提升系统6 kV母线的无功功率和谐波电流补偿效果良好。%Based on principle of sliding mode control,the mine-used resonant impedance type hybrid active power filter system ( RITHAPF) control technology was further researched,and reactive power compensation and harmonic suppression on power grid were made. The switching function modeling method was adopted to make modeling and propose the mathematical model of RITHAPF. Through the derivation of RITHAPF equivalent model,a convergence and stability criterion was put for-ward for RITHAPF system. Combining the influence of discrete index reaching law on discrete sliding mode control,the reac-hing law index of the continuous system was extended to the discrete system,to prove that influence of the discrete index on the system perturbations and external disturbances is still robust. Furthermore,according to the discrete mathematical model of ac-tive power filter,the synovial discrete mathematical model is given. The active part current tracking controller was designed based on the reaching law of the discrete sliding mode control. The simulation results showed that the resonant impedance type

  15. Control Strategies for HCCI Mixed-Mode Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Robert M [ORNL; Edwards, Kevin Dean [ORNL

    2010-03-01

    Delphi Automotive Systems and ORNL established this CRADA to expand the operational range of Homogenous Charge Compression Ignition (HCCI) mixed-mode combustion for gasoline en-gines. ORNL has extensive experience in the analysis, interpretation, and control of dynamic engine phenomena, and Delphi has extensive knowledge and experience in powertrain compo-nents and subsystems. The partnership of these knowledge bases was important to address criti-cal barriers associated with the realistic implementation of HCCI and enabling clean, efficient operation for the next generation of transportation engines. The foundation of this CRADA was established through the analysis of spark-assisted HCCI data from a single-cylinder research engine. This data was used to (1) establish a conceptual kinetic model to better understand and predict the development of combustion instabilities, (2) develop a low-order model framework suitable for real-time controls, and (3) provide guidance in the initial definition of engine valve strategies for achieving HCCI operation. The next phase focused on the development of a new combustion metric for real-time characterization of the combustion process. Rapid feedback on the state of the combustion process is critical to high-speed decision making for predictive control. Simultaneous to the modeling/analysis studies, Delphi was focused on the development of engine hardware and the engine management system. This included custom Delphi hardware and control systems allowing for flexible control of the valvetrain sys-tem to enable HCCI operation. The final phase of this CRADA included the demonstration of conventional and spark assisted HCCI on the multi-cylinder engine as well as the characterization of combustion instabilities, which govern the operational boundaries of this mode of combustion. ORNL and Delphi maintained strong collaboration throughout this project. Meetings were held on a bi-weekly basis with additional reports, presentation, and

  16. HIFU Monitoring and Control with Dual-Mode Ultrasound Arrays

    Science.gov (United States)

    Casper, Andrew Jacob

    The biological effects of high-intensity focused ultrasound (HIFU) have been known and studied for decades. HIFU has been shown capable of treating a wide variety of diseases and disorders. However, despite its demonstrated potential, HIFU has been slow to gain clinical acceptance. This is due, in part, to the difficulty associated with robustly monitoring and controlling the delivery of the HIFU energy. The non-invasive nature of the surgery makes the assessment of treatment progression difficult, leading to long treatment times and a significant risk of under treatment. This thesis research develops new techniques and systems for robustly monitoring HIFU therapies for the safe and efficacious delivery of the intended treatment. Systems and algorithms were developed for the two most common modes of HIFU delivery systems: single-element and phased array applicators. Delivering HIFU with a single element transducer is a widely used technique in HIFU therapies. The simplicity of a single element offers many benefits in terms of cost and overall system complexity. Typical monitoring schemes rely on an external device (e.g. diagnostic ultrasound or MRI) to assess the progression of therapy. The research presented in this thesis explores using the same element to both deliver and monitor the HIFU therapy. The use of a dual-mode ultrasound transducer (DMUT) required the development of an FPGA based single-channel arbitrary waveform generator and high-speed data acquisition unit. Data collected from initial uncontrolled ablations led to the development of monitoring and control algorithms which were implemented directly on the FPGA. Close integration between the data acquisition and arbitrary waveform units allowed for fast, low latency control over the ablation process. Results are presented that demonstrate control of HIFU therapies over a broad range of intensities and in multiple in vitro tissues. The second area of investigation expands the DMUT research to an

  17. Chaos Control in Memristor-based Oscillators Using Intelligent Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Amir Hossein Abolmasoumi

    2014-10-01

    Full Text Available In this paper, Intelligent Sliding Mode Control of chaos in a memristor- based Chua’s oscillator is investigated. In order to gain stabilization and tracking of a sinusoidal input, an appropriate sliding surface is proposed and sliding gain is tuned. Also, to avoid the chattering phenomenon in traditional sliding mode controller, and to reduce the hitting time of the controlled system, an especial genetic algorithm optimization method is suggested. By defining a new objective function and searching for optimal the controller parameters the convergence time and chattering are reduced considerably. The usefulness of the proposed controller with intelligent tuning method for chaos control of memristorbased oscillators is demonstrated in memristor- based Chua's circuit.

  18. Reaction jet and aerodynamics compound control missile autopilot design based on adaptive fuzzy sliding mode control

    Science.gov (United States)

    Wu, Zhenhui; Dong, Chaoyang

    2006-11-01

    Because of nonlinearity and strong coupling of reaction-jet and aerodynamics compound control missile, a missile autopilot design method based on adaptive fuzzy sliding mode control (AFSMC) is proposed in this paper. The universal approximation ability of adaptive fuzzy system is used to approximate the nonlinear function in missile dynamics equation during the flight of high angle of attack. And because the sliding mode control is robustness to external disturbance strongly, the sliding mode surface of the error system is constructed to overcome the influence of approximation error and external disturbance so that the actual overload can track the maneuvering command with high precision. Simulation results show that the missile autopilot designed in this paper not only can track large overload command with higher precision than traditional method, but also is robust to model uncertainty and external disturbance strongly.

  19. Mode of action of Bacillus thuringiensis Cry and Cyt toxins and their potential for insect control

    OpenAIRE

    Bravo, Alejandra; Gill, Sarjeet S.; Soberón, Mario

    2006-01-01

    Bacillus thuringiensis Cry and Cyt protein families are a diverse group of proteins with activity against insects of different orders - Lepidoptera, Coleoptera, Diptera and also against other invertebrates such as nematodes. Their primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores. Among this group of proteins, members of the 3-Domain Cry family are used worldwide for insect control, and their mode of action has been characterized in some...

  20. Optimization of Feedback Control Coils for Resistive Wall Mode Stabilization in DIII-D

    Science.gov (United States)

    Bialek, J.; Boozer, A. H.; Garofalo, A. M.; Mauel, M. E.; Navratil, G. A.; Turnbull, A. D.

    1999-11-01

    Recent experiments in DIII--D on Resistive Wall Mode (RWM) stabilization with active feedback have been very promising. We investigated extensions to the sensor and control coil set that would further improve RWM stabilization. The VALEN computer code models the RWM as an equivalent current distribution on the unperturbed plasma boundary which duplicates the plasma external magnetic field of the mode, as calculated by GATO. This surface current determines the plasma interaction with all conducting structures. In three dimensions the VALEN code models the unstable plasma, passive structure, proposed sensors, and proposed control coils together with the control logic. The problem may be examined as a transient simulation, or for a linear power supply model, as an eigenvalue calculation. A summary of the configurations examined and their predicted effectiveness will be presented.

  1. Active control of convection

    Energy Technology Data Exchange (ETDEWEB)

    Bau, H.H. [Univ. of Pennsylvania, Philadelphia, PA (United States)

    1995-12-31

    Using stability theory, numerical simulations, and in some instances experiments, it is demonstrated that the critical Rayleigh number for the bifurcation (1) from the no-motion (conduction) state to the motion state and (2) from time-independent convection to time-dependent, oscillatory convection in the thermal convection loop and Rayleigh-Benard problems can be significantly increased or decreased. This is accomplished through the use of a feedback controller effectuating small perturbations in the boundary data. The controller consists of sensors which detect deviations in the fluid`s temperature from the motionless, conductive values and then direct actuators to respond to these deviations in such a way as to suppress the naturally occurring flow instabilities. Actuators which modify the boundary`s temperature/heat flux are considered. The feedback controller can also be used to control flow patterns and generate complex dynamic behavior at relatively low Rayleigh numbers.

  2. Actively Controlling Buffet-Induced Excitations

    Science.gov (United States)

    Moses, Robert W.; Pototzky, Anthony S.; Henderson, Douglas A.; Galea, Stephen C.; Manokaran, Donald S.; Zimcik, David G.; Wickramasinghe, Viresh; Pitt, Dale M.; Gamble, Michael A.

    2005-01-01

    High performance aircraft, especially those with twin vertical tails, encounter unsteady buffet loads when flying at high angles of attack. These loads result in significant random stresses, which may cause fatigue damage leading to restricted capabilities and availability of the aircraft. An international collaborative research activity among Australia, Canada and the United States, conducted under the auspices of The Technical Cooperation Program (TTCP) contributed resources toward a program that coalesced a broad range of technical knowledge and expertise into a single investigation to demonstrate the enhanced performance and capability of the advanced active BLA control system in preparation for a flight test demonstration. The research team investigated the use of active structural control to alleviate the damaging structural response to these loads by applying advanced directional piezoelectric actuators, the aircraft rudder, switch mode amplifiers, and advanced control strategies on an F/A-18 aircraft empennage. Some results of the full-scale investigation are presented herein.

  3. Maximum Power Point Tracking Based on Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Nimrod Vázquez

    2015-01-01

    Full Text Available Solar panels, which have become a good choice, are used to generate and supply electricity in commercial and residential applications. This generated power starts with the solar cells, which have a complex relationship between solar irradiation, temperature, and output power. For this reason a tracking of the maximum power point is required. Traditionally, this has been made by considering just current and voltage conditions at the photovoltaic panel; however, temperature also influences the process. In this paper the voltage, current, and temperature in the PV system are considered to be a part of a sliding surface for the proposed maximum power point tracking; this means a sliding mode controller is applied. Obtained results gave a good dynamic response, as a difference from traditional schemes, which are only based on computational algorithms. A traditional algorithm based on MPPT was added in order to assure a low steady state error.

  4. Stable Fuzzy PD Control with Parallel Sliding Mode Compensation with Application to Rigid Manipulator

    Directory of Open Access Journals (Sweden)

    Farzin Piltan

    2013-06-01

    Full Text Available Both fuzzy logic and sliding mode can compensate the steady-state error of proportional-derivative (PD control. This paper presents parallel sliding mode compensations for fuzzy PD controllers. The asymptotic stability of fuzzy PD control with first-order sliding mode compensation in the parallel structure is proven. For the parallel structure, the finite time convergence with a super-twisting second-order sliding-mode is guaranteed.

  5. Power Efficient Higher Order Sliding Mode Control of SR Motor for Speed Control Applications

    Directory of Open Access Journals (Sweden)

    Muhammad Rafiq

    2011-05-01

    Full Text Available This paper presents a novel scheme for speed regulation/tracking of Switched Reluctance (SR motors based on Higher-Order Sliding-Mode technique. In particular, a Second-Order Sliding-Mode Controller (SOSMC based on Super Twisting algorithm is devel-oped. Owing to the peculiar structural properties of SRM, torque produced by each motor phase is a function of phase current as well as rotor position. More importantly, unlike many other motors the polarity of the phase torque in SR motors is solely determined by the rotor position and is independent of the polarity of the applied voltage or phase current. The proposed controller takes advantage of this property and incorporates a commutation scheme which, at any time instant, selects only those motor phases for the computation of control law, which can contribute torque of the desired polarity at that instant. This feature helps in achieving the desired speed regulation/tracking objective in a power efficient manner as control efforts are applied through selective phases and counterproductive phases are left un-energized. This approach also minimizes the power loss in the motor windings thus reducing the heat generation within the motor. In order to highlight the advantages of Higher-Order Sliding-Mode controllers, a classical First-Order Sliding-Mode controller (FOSMC is also developed and applied to the same system. The comparison of the two schemes shows much reduced chattering in case of SOSMC. The performance of the proposed SOSMC controller for speed regulation is also compared with that of another sliding mode speed controller published in the literature.

  6. Active Combustion Control Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Over the past decade, research into active combustion control has yielded impressive results in suppressing thermoacoustic instabilities and widening the...

  7. Mechanisms for multiple activity modes of VTA dopamine neurons

    Directory of Open Access Journals (Sweden)

    Andrew eOster

    2015-07-01

    Full Text Available Midbrain ventral segmental area (VTA dopaminergic neurons send numerous projections to cortical and sub-cortical areas, and diffusely release dopamine (DA to their targets. DA neurons display a range of activity modes that vary in frequency and degree of burst firing. Importantly, DA neuronal bursting is associated with a significantly greater degree of DA release than an equivalent tonic activity pattern. Here, we introduce a single compartmental, conductance-based computational model for DA cell activity that captures the behavior of DA neuronal dynamics and examine the multiple factors that underlie DA firing modes: the strength of the SK conductance, the amount of drive, and GABA inhibition. Our results suggest that neurons with low SK conductance fire in a fast firing mode, are correlated with burst firing, and require higher levels of applied current before undergoing depolarization block. We go on to consider the role of GABAergic inhibition on an ensemble of dynamical classes of DA neurons and find that strong GABA inhibition suppresses burst firing. Our studies suggest differences in the distribution of the SK conductance and GABA inhibition levels may indicate subclasses of DA neurons within the VTA. We further identify, that by considering alternate potassium dynamics, the dynamics display burst patterns that terminate via depolarization block, akin to those observed in vivo in VTA DA neurons and in substantia nigra pars compacta DA cell preparations under apamin application. In addition, we consider the generation of transient burst firing events that are NMDA-initiated or elicited by a sudden decrease of GABA inhibition, that is, disinhibition.

  8. GPU-Based Optimal Control Techniques for Resistive Wall Mode Control on DIII-D

    Science.gov (United States)

    Clement, M.; Navratil, G. A.; Hanson, J. M.; Strait, E. J.

    2014-10-01

    The DIII-D tokamak can excite strong, locked or nearly locked kink modes whose rotation frequencies do not evolve quickly and are slow compared to their growth rates. To control such modes, DIII-D plans to implement a Graphical Processing Unit (GPU) based feedback control system in a low-latency architecture based on system developed on the HBT-EP tokamak. Up to 128 local magnetic sensors will be used to extrapolate the state of the rotating kink mode, which will be used by the feedback algorithm to calculate the required currents for the internal and/or external control coils. Offline techniques for resolving the mode structure of the resistive wall mode (RWM) will be presented and compared along with the proposed GPU implementation scheme and potential real-time estimation algorithms for RWM feedback. Work supported by the US Department of Energy under DE-FG02-07ER54917, DE-FG02-04ER54761, and DE-FC02-04ER54698.

  9. X33 Reusable Launch Vehicle Control on Sliding Modes: Concepts for a Control System Development

    Science.gov (United States)

    Shtessel, Yuri B.

    1998-01-01

    Control of the X33 reusable launch vehicle is considered. The launch control problem consists of automatic tracking of the launch trajectory which is assumed to be optimally precalculated. It requires development of a reliable, robust control algorithm that can automatically adjust to some changes in mission specifications (mass of payload, target orbit) and the operating environment (atmospheric perturbations, interconnection perturbations from the other subsystems of the vehicle, thrust deficiencies, failure scenarios). One of the effective control strategies successfully applied in nonlinear systems is the Sliding Mode Control. The main advantage of the Sliding Mode Control is that the system's state response in the sliding surface remains insensitive to certain parameter variations, nonlinearities and disturbances. Employing the time scaling concept, a new two (three)-loop structure of the control system for the X33 launch vehicle was developed. Smoothed sliding mode controllers were designed to robustly enforce the given closed-loop dynamics. Simulations of the 3-DOF model of the X33 launch vehicle with the table-look-up models for Euler angle reference profiles and disturbance torque profiles showed a very accurate, robust tracking performance.

  10. Research on Active Vibration Suppression of Magnetically Suspended Flywheel Based on Sliding Mode Variable Structure Control%磁悬浮飞轮滑模变结构主动振动控制研究

    Institute of Scientific and Technical Information of China (English)

    田希晖; 刘虎

    2013-01-01

    Focusing on synchronous vibration caused by unbalance of magnetically suspended flywheel, dynamics model of the magnetic bearing-rotor system is set up. The unbalance force and moments are observed through using the sliding mode disturbance observer. In order to reduce the order of the observer, tracking-differentiator (TD) is used to estimate the derivatives of the displacement signals to get velocity signal. The output of the TD is introduced to magnetic bearing controller, in order to compensate the synchronous force and moments observed by disturbance observer. Simulation results indicate that sliding mode disturbance observer can observe the flywheel rotor's unbalance force and moments, and controller could compensate unbalance disturbance of flywheel rotor.%通过对不平衡扰动力作用下的磁轴承-转子系统进行建模,针对磁悬浮飞轮转子不平衡量引起的同频扰动,采用滑模变结构扰动观测器对不平衡扰动力和力矩进行观测.为得到低阶观测器,采用二阶跟踪微分器估计位移传感器输出信号的微分,得到传感器速度信号.将滑模观测器的输出引入磁轴承控制器,对观测得到的同频不平衡扰动力和力矩进行补偿.仿真结果表明,采用滑模变结构观测器可观测飞轮转子不平衡力和力矩,利用磁轴承控制器实现了对飞轮转子不平衡扰动的补偿.

  11. Adaptive Global Sliding Mode Control for MEMS Gyroscope Using RBF Neural Network

    Directory of Open Access Journals (Sweden)

    Yundi Chu

    2015-01-01

    Full Text Available An adaptive global sliding mode control (AGSMC using RBF neural network (RBFNN is proposed for the system identification and tracking control of micro-electro-mechanical system (MEMS gyroscope. Firstly, a new kind of adaptive identification method based on the global sliding mode controller is designed to update and estimate angular velocity and other system parameters of MEMS gyroscope online. Moreover, the output of adaptive neural network control is used to adjust the switch gain of sliding mode control dynamically to approach the upper bound of unknown disturbances. In this way, the switch item of sliding mode control can be converted to the output of continuous neural network which can weaken the chattering in the sliding mode control in contrast to the conventional fixed gain sliding mode control. Simulation results show that the designed control system can get satisfactory tracking performance and effective estimation of unknown parameters of MEMS gyroscope.

  12. Nonlinear Predictive Control of Semi-Active Landing Gear System

    OpenAIRE

    Wu, Dongsu; Gu, Hongbin; Liu, Hui

    2010-01-01

    The application of model predictive control and constructive nonlinear control methodology to semi-active landing gear system is studied in this paper. A unified shock absorber mathematical model incorporates solenoid valve’s electromechanical and magnetic dynamics is built to facilitate simulation and controller design. Then we propose a hierarchical control structure to deal with the high nonlinearity. A dual mode model predictive controller as an outer loop controller is developed to gen...

  13. Active Control of Suspension Bridges

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    In this paper some recent research on active control of very long suspension bridges, is presented. The presentation is based on research work at Aalborg University, Denmark. The active control system is based on movable flaps attached to the bridge girder. Wind load on bridges with or without...... flaps attached to the girder is briefly presented. A simple active control system is discussed. Results from wind tunnel experiments with a bridge section show that flaps can be used effectively to control bridge girder vibrations. Flutter conditions for suspension bridges with and without flaps...

  14. A novel sliding mode nonlinear proportional-integral control scheme for controlling chaos

    Institute of Scientific and Technical Information of China (English)

    Yu Dong-Chuan; Wu Ai-Guo; Yang Chao-Ping

    2005-01-01

    A novel sliding mode nonlinear proportional-integral control (SMNPIC) scheme is proposed for driving a class of time-variant chaotic systems with uncertainty to arbitrarily desired trajectory with high accuracy. The SMNPIC differs from the previous sliding mode techniques in the sense that a nonlinear proportional-integral action of sliding function is involved in control law, so that both the steady-state error and the high-frequency chattering are reduced,and meanwhile, robustness and fastness are guaranteed. In addition, the proposed SMNPIC actually acts as a class of nonlinear proportional-integral-differential (PID) controller, in which the tracking error and its derivatives up to (n-1)thorder as well as the integral of tracking error are considered, so that more useful information than traditional PID can be implemented and better dynamic and static characteristics can obtained. Its good performance for chaotic control is illustrated through a During-Holmes system with uncertainty.

  15. Speed Sensorless Vector Control of Unbalanced Three-Phase Induction Motor with Adaptive Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Mohammad Jannati

    2014-05-01

    Full Text Available This paper presents a technique for speed sensorless Rotor Flux Oriented Control (RFOC of 3-phase Induction Motor (IM under open-phase fault (unbalanced or faulty IM. The presented RFOC strategy is based on rotational transformation. An adaptive sliding mode control system with an adaptive switching gain is proposed instead of the speed PI controller. Using an adaptive sliding mode control causes the proposed speed sensorless RFOC drive system to become insensitive to uncertainties such as load disturbances and parameter variations. Moreover, with adaptation of the sliding switching gain, calculation of the system uncertainties upper bound is not needed. Finally, simulation results have been presented to confirm the good performance of the proposed method.

  16. Benefit Evaluation on the Control Mode for Typical Karst Rocky Desertification in Guizhou Province,China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Control mode for typical karst rocky desertification in Guizhou Province,China is selected as the research object.The ecological benefit,the social and economic benefit and the popularization prospect of mode are selected as evaluation indices.Evaluation index system of control modebenefits for karst rocky desertification is established.The Dingtan mode and the Wangjiazhai-Yangchangdong small watershed control mode are se-lected as evaluation objects.Preliminary assessment on the two modes are carried out by Analytic Hierarchy Process,grading evaluation,and com-prehensive evaluation method.Result shows that comprehensive score of Dingtan mode is 3.81,which is higher than the score of Wangjiazhai-Yangchangdong small watershed control mode(3.11).In the aspects of ecological benefit and social and economic benefit,Dingtan mode(4.83and 3.258) is superior than the Wangjiazhai-Yangchangdong small watershed control mode(3.38 and 2.531).In the aspect of popularization pros-pect of mode,score of Dingtan mode(3) is lower than that of Wangjiazhai-Yangchangdong small watershed control mode(3.333).Therefore,theevaluation index system has certain science and offers reference and guidance for the karst rocky desertification control in southwest China.

  17. A Mode Switching Sliding-mode Controller with Observer-based State-Dependent Boundary Layer and Its Application

    Directory of Open Access Journals (Sweden)

    Chao-Yu Hsu

    2007-06-01

    Full Text Available This paper presents a mode-switching sliding-mode control (MSMC scheme that combines different sliding-mode control schemes to alleviate adverse effect while achieving precise control tasks. To achieve certain robustness and chattering alleviation, a design of disturbance observer based state-dependent boundary layer is proposed. The proposed method will provide a state-dependent boundary-layer in which the unknown dynamics is estimated a disturbance observer and then utilize it to calculate the width of boundary layer on-line. The convergent analysis of this state-dependent boundary-layer is provided with two theorems. Finally, its efficacy is further validated through experiments on the regulation control of a maglev platform.

  18. Vibration control of flexible beams using an active hinge

    Science.gov (United States)

    Cudney, H. H., Jr.; Inman, D. J.; Horner, G. C.

    1985-01-01

    The use of an active hinge to attenuate the transverse vibrations of a flexible beam is examined. A slender aluminum beam is suspended vertically, cantilevered at the top. An active hinge is placed at the node of the second vibration mode. The active hinge consists of a torque motor, strain gauge, and tachometer. A control law is implemented using both beam-bending strain and the relative angular velocity measured at this hinge, thereby configuring the hinge to act as an active damper. Results from implementing this control law show little improvement in the first mode damping ratio, 130 percent increase in the second mode damping ratio, and 180 percent increase in the third mode damping ratio. The merits of using a motor with a gearbox are discussed.

  19. Diving control of underactuated unmanned undersea vehicle using integral-fast terminal sliding mode control

    Institute of Scientific and Technical Information of China (English)

    严浙平; 于浩淼; 侯恕萍

    2016-01-01

    The problem of diving control for an underactuated unmanned undersea vehicle (UUV) considering the presence of parameters perturbations and wave disturbances was addressesed. The vertical motion of an UUV was divided into two noninteracting subsystems for surge velocity control and diving. To stabilize the vertical motion system, the surge velocity and the depth control controllers were proposed using backstepping technology and an integral-fast terminal sliding mode control (IFTSMC). It is proven that the proposed control scheme can guarantee that all the error signals in the whole closed-loop system globally converge to the sliding surface in finite time and asymptotically converge to the origin along the sliding surface. With a unified control parameters for different motion states, a series of numerical simulation results illustrate the effectiveness of the above designed control scheme, which also shows strong robustness against parameters perturbations and wave disturbances.

  20. Mode shifting in school travel mode: examining the prevalence and correlates of active school transport in Ontario, Canada

    Directory of Open Access Journals (Sweden)

    Buliung Ron

    2011-08-01

    Full Text Available Abstract Background Studies examining the correlates of school transport commonly fail to make the distinction between morning and afternoon school trips. The purpose of this study was to examine the prevalence and correlates of mode shift from passive in the morning to active in the afternoon among elementary and secondary school students in Ontario, Canada. Methods Data were derived from the 2009 cycle of the Ontario Student Drug Use and Health Survey (OSDUHS. 3,633 students in grades 7 through 12 completed self-administered questionnaires. Socio-demographic, behavioural, psychological, and environmental predictors of active school transport (AST were assessed using logistic regression. Results Overall, 47% and 38% of elementary school students reported AST to and from school, respectively. The corresponding figures were 23% and 32% for secondary school students. The prevalence of AST varied temporarily and spatially. There was a higher prevalence of walking/biking found for elementary school students than for secondary school students, and there was an approximate 10% increase in AST in the afternoon. Different correlates of active school transport were also found across elementary and secondary school students. For all ages, students living in urban areas, with a shorter travel time between home and school, and having some input to the decision making process, were more likely to walk to and from school. Conclusions Future research examining AST should continue to make the analytic distinction between the morning and afternoon trip, and control for the moderating effect of age and geography in predicting mode choice. In terms of practice, these variations highlight the need for school-specific travel plans rather than 'one size fits all' interventions in promoting active school transport.

  1. Active control of transmitted sound in buildings

    Science.gov (United States)

    Thompsett, Russell Harvey George

    The problem of noise from neighbours has increased dramatically over the last few years. Many of the noise complaints are due to the high level, low frequency noise from modern stereo equipment, and are often described in terms of the low frequency characteristics of the music; the repetitive, booming, bass beat. The objective of this research was to establish the feasibility of applying active noise control to alleviate this problem. The initial approach was to evaluate the possibility of exploiting the dominance of individual modes in the response of rooms at low frequency to effect global control. However, initial investigations using a modal model of the sound field revealed that this would be difficult due to the contribution of many acoustic modes excited off resonance. This conclusion was supported by measurements of acoustic room responses in typical buildings, illustrating a non-resonant characteristic. Consequently, attention was turned to the feasibility of using local active control systems to create zones of quiet by concentrating control at a specific location near the observers ears, for example in a seat headrest, or near the pillows of a bed. The lack of a reference signal in either approach requires the use of a feedback control strategy. With a typically non-resonant system, the predictability in the disturbance necessary for successful feedback control must be contained in the primary excitation, namely the music. Examples of different music styles were investigated and of those with the potential to be a nuisance surprisingly few were significantly more predictable than a random disturbance. As expected the most encouraging control performance simulations were found for modern dance music, with a strong repetitive beat. A real-time, local controller was demonstrated in the laboratory with such a disturbance signal and the properties of the quiet zone were measured. The subjective response when hearing the controller in operation was found to be

  2. Active control of radiated sound using nearfield pressure sensing

    Institute of Scientific and Technical Information of China (English)

    CHEN Ke'an; YIN Xuefei

    2004-01-01

    Based on nearfield sound pressure sensing to pick up error information, an approach for constructing active acoustic structure to effectively reduce radiated sound power at low frequency is proposed. The idea is that a nearfield pressure after active control is used as error signals and transformed into an objective function in adaptive active control process.Firstly sound power expression using near-field pressure radiated from a flexible structure is derived, and then three kind of nearfield pressure based active control strategies, I.e. Minimization of radiated sound power, minimization of sound power for dominant radiation modes and minimization of sound power for modified dominant radiation modes are respectively presented and applied to active control of radiated single and broadband noise. Finally computer simulations on sound power reduction under three strategies are conducted and it is shown that the proposed active control strategies are invalid and considerable reduction in radiated sound power can be achieved.

  3. Speed Control of Induction Motor Using New Sliding Mode Control Technique

    Directory of Open Access Journals (Sweden)

    Aamir Hashim Obeid Ahmed

    2010-06-01

    Full Text Available Induction Motors have been used as the workhorse in the industry for a long time due to its easy build, high robustness, and generally satisfactory efficiency. However, they are significantly more difficult to control than DC motors. One of the problems which might cause unsuccessful attempts for designing a proper controller would be the time varying nature of parameters and variables which might be changed while working with the motion systems. One of the best suggested solutions to solve this problem would be the use of Sliding Mode Control (SMC. This paper presents the design of a new controller for a vector control induction motor drive that employs an outer loop speed controller using SMC. Several tests were performed to evaluate the performance of the new controller method, and two other sliding mode controller techniques. From the comparative simulation results, one can conclude that the new controller law provides high performance dynamic characteristics and is robust with regard to plant parameter variations.

  4. Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes

    Institute of Scientific and Technical Information of China (English)

    Jia Yinghong; Xu Shijie

    2016-01-01

    An adaptive sliding mode control (ASMC) law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot. Each joint of the system is a free ball joint capable of rotating with three degrees of freedom (DOF). A cluster of control moment gyroscopes (CMGs) is mounted on each link and the base to actuate the system. The modified Rodrigues parameters (MRPs) are employed to describe the angular displacements, and the equations of motion are derived using Kane’s equations. The controller for each link or the base is designed sep-arately in decentralized scheme. The unknown disturbances, inertia parameter uncertainties and nonlinear uncertainties are classified as a ‘‘lumped” matched uncertainty with unknown upper bound, and a continuous sliding mode control (SMC) law is proposed, in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty. A gen-eral amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input. Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov’s method. Simulation results based on a three-link system verify the effectiveness of the proposed controller.

  5. Decentralized adaptive sliding mode control of a space robot actuated by control moment gyroscopes

    Directory of Open Access Journals (Sweden)

    Jia Yinghong

    2016-06-01

    Full Text Available An adaptive sliding mode control (ASMC law is proposed in decentralized scheme for trajectory tracking control of a new concept space robot. Each joint of the system is a free ball joint capable of rotating with three degrees of freedom (DOF. A cluster of control moment gyroscopes (CMGs is mounted on each link and the base to actuate the system. The modified Rodrigues parameters (MRPs are employed to describe the angular displacements, and the equations of motion are derived using Kane’s equations. The controller for each link or the base is designed separately in decentralized scheme. The unknown disturbances, inertia parameter uncertainties and nonlinear uncertainties are classified as a “lumped” matched uncertainty with unknown upper bound, and a continuous sliding mode control (SMC law is proposed, in which the control gain is tuned by the improved adaptation laws for the upper bound on norm of the uncertainty. A general amplification function is designed and incorporated in the adaptation laws to reduce the control error without conspicuously increasing the magnitude of the control input. Uniformly ultimate boundedness of the closed loop system is proved by Lyapunov’s method. Simulation results based on a three-link system verify the effectiveness of the proposed controller.

  6. Platelet serotonin transporter function predicts default-mode network activity.

    Directory of Open Access Journals (Sweden)

    Christian Scharinger

    Full Text Available The serotonin transporter (5-HTT is abundantly expressed in humans by the serotonin transporter gene SLC6A4 and removes serotonin (5-HT from extracellular space. A blood-brain relationship between platelet and synaptosomal 5-HT reuptake has been suggested, but it is unknown today, if platelet 5-HT uptake can predict neural activation of human brain networks that are known to be under serotonergic influence.A functional magnetic resonance study was performed in 48 healthy subjects and maximal 5-HT uptake velocity (Vmax was assessed in blood platelets. We used a mixed-effects multilevel analysis technique (MEMA to test for linear relationships between whole-brain, blood-oxygen-level dependent (BOLD activity and platelet Vmax.The present study demonstrates that increases in platelet Vmax significantly predict default-mode network (DMN suppression in healthy subjects independent of genetic variation within SLC6A4. Furthermore, functional connectivity analyses indicate that platelet Vmax is related to global DMN activation and not intrinsic DMN connectivity.This study provides evidence that platelet Vmax predicts global DMN activation changes in healthy subjects. Given previous reports on platelet-synaptosomal Vmax coupling, results further suggest an important role of neuronal 5-HT reuptake in DMN regulation.

  7. Optically active mechanical modes of tapered optical fibers

    CERN Document Server

    Wuttke, Chrisitan; Rauschenbeutel, Arno

    2013-01-01

    Tapered optical fibers with a nanofiber waist are widely used tools for efficient coupling of light to photonic devices or quantum emitters via the nanofiber's evanescent field. In order to ensure well-controlled coupling, the phase and polarization of the nanofiber guided light field have to be stable. Here, we show that in typical tapered optical fibers these quantities exhibit high-frequency thermal fluctuations. They originate from high-Q torsional oscillations that opto-mechanically couple to the nanofiber-guided light. We present a simple ab-initio theoretical model that quantitatively explains the torsional mode spectrum and that can be used to design tapered optical fibers with tailored mechanical properties.

  8. Mode of action of Bacillus thuringiensis Cry and Cyt toxins and their potential for insect control.

    Science.gov (United States)

    Bravo, Alejandra; Gill, Sarjeet S; Soberón, Mario

    2007-03-15

    Bacillus thuringiensis Crystal (Cry) and Cytolitic (Cyt) protein families are a diverse group of proteins with activity against insects of different orders--Lepidoptera, Coleoptera, Diptera and also against other invertebrates such as nematodes. Their primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores. Among this group of proteins, members of the 3-Domain Cry family are used worldwide for insect control, and their mode of action has been characterized in some detail. Phylogenetic analyses established that the diversity of the 3-Domain Cry family evolved by the independent evolution of the three domains and by swapping of domain III among toxins. Like other pore-forming toxins (PFT) that affect mammals, Cry toxins interact with specific receptors located on the host cell surface and are activated by host proteases following receptor binding resulting in the formation of a pre-pore oligomeric structure that is insertion competent. In contrast, Cyt toxins directly interact with membrane lipids and insert into the membrane. Recent evidence suggests that Cyt synergize or overcome resistance to mosquitocidal-Cry proteins by functioning as a Cry-membrane bound receptor. In this review we summarize recent findings on the mode of action of Cry and Cyt toxins, and compare them to the mode of action of other bacterial PFT. Also, we discuss their use in the control of agricultural insect pests and insect vectors of human diseases. PMID:17198720

  9. Diagnostic for two-mode variable valve activation device

    Science.gov (United States)

    Fedewa, Andrew M

    2014-01-07

    A method is provided for diagnosing a multi-mode valve train device which selectively provides high lift and low lift to a combustion valve of an internal combustion engine having a camshaft phaser actuated by an electric motor. The method includes applying a variable electric current to the electric motor to achieve a desired camshaft phaser operational mode and commanding the multi-mode valve train device to a desired valve train device operational mode selected from a high lift mode and a low lift mode. The method also includes monitoring the variable electric current and calculating a first characteristic of the parameter. The method also includes comparing the calculated first characteristic against a predetermined value of the first characteristic measured when the multi-mode valve train device is known to be in the desired valve train device operational mode.

  10. Activation of different MEMS resonant modes with pulsed digital oscillators

    OpenAIRE

    Domínguez Pumar, Manuel; Blokhina, Elena; Pons Nin, Joan; Feely, Orla; Sanchez Rojas, Jose Luis

    2010-01-01

    The objective of this work is to show that is possible to excite different vibration modes of MEMS resonators using Pulsed Digital Oscillators. This class of circuits exhibit two different behaviours: the oscillation and the anti-oscillation mode. In the oscillation mode, th eoscillator in average provides energy to the resonator, whereas in the anti-oscillation mode, it extracts energy of the resonator until a limit cyucle is reached near the origin. It will be shown that by preparing suitab...

  11. Design Intelligent PID like Fuzzy Sliding Mode Controller for Spherical Motor

    OpenAIRE

    Farzin Matin; Farzin Piltan; Hamid Cheraghi; Nasim Sobhani; Maryam Rahmani

    2014-01-01

    The minimum rule base Proportional Integral Derivative (PID) Fuzzy Sliding Mode Controller (SMC) with application to spherical motor is presented in this research. The popularity of PID Fuzzy Sliding Mode Controller can be attributed to their robust performance in a wide range of operating conditions and partly to their functional simplicity. The process of setting of PID Fuzzy Sliding Mode Controller can be determined as an optimization task. Over the years, use of intelligent strategies for...

  12. CONTROL SYSTEM FEATURES OF MAGNETIC-PULSE INSTALLATION AT UNIPOLAR MODE

    Directory of Open Access Journals (Sweden)

    Dzyubenko, A.

    2012-06-01

    Full Text Available Construction features of monitoring and control system of magnetic pulse installation at work in unipolar mode were detected. Installation control system algorithm at work in multiple repeating mode of discharge pulses is proposed. Description of monitoring and control system structure schemes and their purposes have been conducted.

  13. Adaptive Sliding Mode Control of Chaos in Permanent Magnet Synchronous Motor via Fuzzy Neural Networks

    Directory of Open Access Journals (Sweden)

    Tat-Bao-Thien Nguyen

    2014-01-01

    Full Text Available In this paper, based on fuzzy neural networks, we develop an adaptive sliding mode controller for chaos suppression and tracking control in a chaotic permanent magnet synchronous motor (PMSM drive system. The proposed controller consists of two parts. The first is an adaptive sliding mode controller which employs a fuzzy neural network to estimate the unknown nonlinear models for constructing the sliding mode controller. The second is a compensational controller which adaptively compensates estimation errors. For stability analysis, the Lyapunov synthesis approach is used to ensure the stability of controlled systems. Finally, simulation results are provided to verify the validity and superiority of the proposed method.

  14. Direct Torque Control of Saturated Doubly-Fed Induction Generator using High Order Sliding Mode Controllers

    Directory of Open Access Journals (Sweden)

    Elhadj BOUNADJA

    2016-07-01

    Full Text Available The present work examines a direct torque control strategy using a high order sliding mode controllers of a doubly-fed induction generator (DFIG incorporated in a wind energy conversion system and working in saturated state. This research is carried out to reach two main objectives. Firstly, in order to introduce some accuracy for the calculation of DFIG performances, an accurate model considering magnetic saturation effect is developed. The second objective is to achieve a robust control of DFIG based wind turbine. For this purpose, a Direct Torque Control (DTC combined with a High Order Sliding Mode Control (HOSMC is applied to the DFIG rotor side converter. Conventionally, the direct torque control having hysteresis comparators possesses major flux and torque ripples at steady-state and moreover the switching frequency varies on a large range. The new DTC method gives a perfect decoupling between the flux and the torque. It also reduces ripples in these grandeurs. Finally, simulated results show, accurate dynamic performances, faster transient responses and more robust control are achieved.

  15. Cavity mode control in side-coupled periodic waveguides: theory and experiment

    DEFF Research Database (Denmark)

    Ha, Sangwoo; Sukhorukov, A.; Lavrinenko, Andrei;

    2010-01-01

    as the cavities are brought closer. We show that the longitudinal shift enables flexible control over the fundamental modes, whose frequency detuning can be reduced down to zero. Our coupled-mode theory analysis reveals an intrinsic link between the mode tuning and the transformation of slow-light dispersion...

  16. A Novel Control Approach Based on Second Order Sliding Modes & Its Application to Hydraulic Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.

    2013-01-01

    Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics....... chattering. Simulation studies confirm the announced properties when applied to a hydraulic drive model subjected to strong variations in supply pressure and friction.......Sliding modes impose strong robustness toward parametric plant uncertainties and disturbances and accurate tracking performance in control systems. However, in physical systems the application of sliding modes may give rise to undesirable chattering of the control signal due to actuator dynamics...

  17. Sliding mode-based lateral vehicle dynamics control using tyre force measurements

    Science.gov (United States)

    Kunnappillil Madhusudhanan, Anil; Corno, Matteo; Holweg, Edward

    2015-11-01

    In this work, a lateral vehicle dynamics control based on tyre force measurements is proposed. Most of the lateral vehicle dynamics control schemes are based on yaw rate whereas tyre forces are the most important variables in vehicle dynamics as tyres are the only contact points between the vehicle and road. In the proposed method, active front steering is employed to uniformly distribute the required lateral force among the front left and right tyres. The force distribution is quantified through the tyre utilisation coefficients. In order to address the nonlinearities and uncertainties of the vehicle model, a gain scheduling sliding-mode control technique is used. In addition to stabilising the lateral dynamics, the proposed controller is able to maintain maximum lateral acceleration. The proposed method is tested and validated on a multi-body vehicle simulator.

  18. A Michelson controlled-not gate with a single-lens astigmatic mode converter.

    Science.gov (United States)

    Souza, C E R; Khoury, A Z

    2010-04-26

    We propose and demonstrate experimentally a single lens design for an astigmatic mode converter that transforms the transverse mode of paraxial optical beams. As an application, we implement a controlled-not gate based on a Michelson interferometer in which the photon polarization is the control bit and the first order transverse mode is the target. As a further application, we also build a transverse mode parity sorter which can be useful for quantum information processing as a measurement device for the transverse mode qubit. PMID:20588767

  19. Sliding Mode Control Design for a Class of SISO Systems with Uncertain Sliding Surface

    Directory of Open Access Journals (Sweden)

    Guofeng Wang

    2013-01-01

    Full Text Available The problem of designing a sliding mode controller with uncertain sliding surface for a class of uncertain single-input-single-output systems is studied. The design case is handled by using the invariant transformation first in order to separate the sliding mode and the reaching mode of the sliding mode control system. It is shown that the sliding mode design needs not to consider the uncertainties of the sliding surface, which can be handled in the reaching phase design. The results generalize the robust design of the reaching phase such that one specific reaching phase design may agree with several sliding surfaces.

  20. Spatial steadiness of individual disorder modes upon controlled spectral tuning

    Science.gov (United States)

    Caselli, Niccolò; Riboli, Francesco; Intonti, Francesca; La China, Federico; Biccari, Francesco; Gerardino, Annamaria; Gurioli, Massimo

    2016-07-01

    Recent innovative applications in disordered photonics would strongly benefit from the possibility to achieve spectral tuning of the individual disorder localized photonic modes without affecting their spatial distributions. Here, we design and fabricate a two-dimensional disordered photonic system, made of a GaAs slab patterned with randomly distributed circular air scattering centers, supporting localized light modes with very small modal volume. The photoluminescence of InAs quantum dots embedded in the slab is used as a probe for near field experiments and gives direct access to the electric field intensity distribution of the localized random modes. We demonstrate that laser assisted oxidation of the GaAs slab performed by near field illumination can be used for a gentle tuning of the individual random modes without modifying the subtle balance leading to light localization given by multiple scattering.

  1. Progress in analytical methods to predict and control azimuthal combustion instability modes in annular chambers

    OpenAIRE

    Bauerheim, Michaël; Nicoud, Franck; Poinsot, Thierry

    2016-01-01

    Longitudinal low-frequency thermoacoustic unstable modes in combustion chambers have been intensively studied experimentally, numerically, and theoretically, leading to significant progress in both understanding and controlling these acoustic modes. However, modern annular gas turbines may also exhibit azimuthal modes, which are much less studied and feature specific mode structures and dynamic behaviors, leading to more complex situations. Moreover, dealing with 10–20 burners mounted in the ...

  2. High Power Continuous-Wave Actively Mode-Locked Diode-Pumped Nd:YAG Laser

    Institute of Scientific and Technical Information of China (English)

    LING Wei-Jun; ZHANG Shao-Gang; ZHANG Ming-Xia; DONG Zhong; LI Ke; ZUO Yin-Yan; GUO Xiao-Hua; JIA Yu-Lei

    2010-01-01

    @@ We demonstrate a diode-pumped cw mode-locked Nd:YAG by an acousto-optic mode locker.A mode-locked pulse with duration of 345 ps and output power of 12 W is obtained.The resonator design shows three advantages:a larger mode volume,high stability against thermal lens fluctuations,and excellent beam quality with TE00 mode.Different from previous active mode locking designs,we employ a frequency stabilizer and a phase-lock loop circuit to ensure the mode locking stable operation.

  3. Impedance Control of the Rehabilitation Robot Based on Sliding Mode Control

    Science.gov (United States)

    Zhou, Jiawang; Zhou, Zude; Ai, Qingsong

    As an auxiliary treatment, the 6-DOF parallel robot plays an important role in lower limb rehabilitation. In order to improve the efficiency and flexibility of the lower limb rehabilitation training, this paper studies the impedance controller based on the position control. A nonsingular terminal sliding mode control is developed to ensure the trajectory tracking precision and in contrast to traditional PID control strategy in the inner position loop, the system will be more stable. The stability of the system is proved by Lyapunov function to guarantee the convergence of the control errors. Simulation results validate the effectiveness of the target impedance model and show that the parallel robot can adjust gait trajectory online according to the human-machine interaction force to meet the gait request of patients, and changing the impedance parameters can meet the demands of different stages of rehabilitation training.

  4. A Riding-through Technique for Seamless Transition between Islanded and Grid-Connected Modes of Droop-Controlled Inverters

    Directory of Open Access Journals (Sweden)

    Shang-Hung Hu

    2016-09-01

    Full Text Available This paper presents a seamless transition method for a droop-controlled inverter. The droop control is suitable to make the inverter work as a voltage source in both islanded and grid-connected modes, however, the transfer between theses modes can result in a big inrush current that may damage the system. The proposed method allows the droop-controlled inverter to improve the transient response when transferring between modes, by detecting the inrush current, activating a current control loop during transients, and then transferring back to droop-controlled mode smoothly by using a virtual inductance loop. In addition, a local phase-locked-loop (PLL is proposed to align the inverter voltage with the grid in order to reduce the transient current during the transition. Therefore, the droop-controlled inverter is able to operate in both grid-connected and islanded modes, providing as well a smooth transition between them, requiring neither synchronization signals nor grid-side information. The control algorithm and design procedure are presented. Experimental results from a laboratory prototype validate the effectiveness of the proposed method.

  5. Modelling Control Process and Control Mode with Synchronising Orthogonal State Machines

    OpenAIRE

    Snook, Colin

    2011-01-01

    In this short paper we describe early work on a case study concerning a power window control unit. We use UML-B state machines to simultaneously model both the cyclic processing schedule and the mode of control behaviour. We find this a useful way to visualise the model, particularly when the state machines are animated via the Pro-B animator. We verify the state machines using the Event-B proof tools. We envisage new developments to the UML-B tool set to improve support for this modelling te...

  6. Control of Chaos in Rate-Dependent Friction-Induced Vibration Using Adaptive Sliding Mode Control and Impulse Damper

    Directory of Open Access Journals (Sweden)

    Ehsan Maani Miandoab

    2013-01-01

    Full Text Available Two different control methods, namely, adaptive sliding mode control and impulse damper, are used to control the chaotic vibration of a block on a belt system due to the rate-dependent friction. In the first method, using the sliding mode control technique and based on the Lyapunov stability theory, a sliding surface is determined, and an adaptive control law is established which stabilizes the chaotic response of the system. In the second control method, the vibration of this system is controlled by an impulse damper. In this method, an impulsive force is applied to the system by expanding and contracting the PZT stack according to efficient control law. Numerical simulations demonstrate the effectiveness of both methods in controlling the chaotic vibration of the system. It is shown that the settling time of the controlled system using impulse damper is less than that one controlled by adaptive sliding mode control; however, it needs more control effort.

  7. A new method to minimize the chattering phenomenon in sliding mode control based on intelligent control for induction motor drives

    Directory of Open Access Journals (Sweden)

    Bendaas Ismail

    2013-01-01

    Full Text Available This paper presents new method toward the design of hybrid control with sliding-mode (SMC plus fuzzy logic control (FLC for induction motors. As the variations of both control system parameters and operating conditions occur, the conventional control methods may not be satisfied further. Sliding mode control is robust with respect to both induction motor parameter variations and external disturbances. By embedding a fuzzy logic control into the sliding mode control, the chattering (torque-ripple problem with varying parameters, which are the main disadvantage in sliding-mode control, can be suppressed, Simulation results of the proposed control theme present good dynamic and steady-state performances as compared to the classical SMC from aspects for torque-ripple minimization, the quick dynamic torque response and robustness to disturbance and variation of parameters.

  8. Optical control of antibacterial activity

    Science.gov (United States)

    Velema, Willem A.; van der Berg, Jan Pieter; Hansen, Mickel J.; Szymanski, Wiktor; Driessen, Arnold J. M.; Feringa, Ben L.

    2013-11-01

    Bacterial resistance is a major problem in the modern world, stemming in part from the build-up of antibiotics in the environment. Novel molecular approaches that enable an externally triggered increase in antibiotic activity with high spatiotemporal resolution and auto-inactivation are highly desirable. Here we report a responsive, broad-spectrum, antibacterial agent that can be temporally activated with light, whereupon it auto-inactivates on the scale of hours. The use of such a ‘smart’ antibiotic might prevent the build-up of active antimicrobial material in the environment. Reversible optical control over active drug concentration enables us to obtain pharmacodynamic information. Precisely localized control of activity is achieved, allowing the growth of bacteria to be confined to defined patterns, which has potential for the development of treatments that avoid interference with the endogenous microbial population in other parts of the organism.

  9. Simulation of sliding mode impedance control for a 6 DOF antrhopomorphic robot

    NARCIS (Netherlands)

    Broenink, Jan F.; Visser, Martijn; Tiernego, Martin L.J.; Zobel, Richard; Moeller, Ditmar

    1998-01-01

    Robust control is a way of dealing with model uncertainties that can render the controller less sensitive to modelling errors and disturbances. Herein, the properties of sliding mode control are applied to impedance control to form a robust impedance con-troller. The proposed controller consists of

  10. Fault Diagnosis and Fault-Tolerant Control of Uncertain Robot Manipulators Using High-Order Sliding Mode

    Directory of Open Access Journals (Sweden)

    Mien Van

    2016-01-01

    Full Text Available A robust fault diagnosis and fault-tolerant control (FTC system for uncertain robot manipulators without joint velocity measurement is presented. The actuator faults and robot manipulator component faults are considered. The proposed scheme is designed via an active fault-tolerant control strategy by combining a fault diagnosis scheme based on a super-twisting third-order sliding mode (STW-TOSM observer with a robust super-twisting second-order sliding mode (STW-SOSM controller. Compared to the existing FTC methods, the proposed FTC method can accommodate not only faults but also uncertainties, and it does not require a velocity measurement. In addition, because the proposed scheme is designed based on the high-order sliding mode (HOSM observer/controller strategy, it exhibits fast convergence, high accuracy, and less chattering. Finally, computer simulation results for a PUMA560 robot are obtained to verify the effectiveness of the proposed strategy.

  11. L1 adaptive control with sliding-mode based adaptive law

    Institute of Scientific and Technical Information of China (English)

    Jie LUO; Chengyu CAO

    2015-01-01

    This paper presents an adaptive control scheme with an integration of sliding mode control into the L1 adaptive control architecture, which provides good tracking performance as well as robustness against matched uncertainties. Sliding mode control is used as an adaptive law in the L1 adaptive control architecture, which is considered as a virtual control of error dynamics between estimated states and real states. Low-pass filtering mechanism in the control law design prevents a discontinuous signal in the adaptive law from appearing in actual control signal while maintaining control accuracy. By using sliding mode control as a virtual control of error dynamics and introducing the low-pass filtered control signal, the chattering effect is eliminated. The performance bounds between the close-loop adaptive system and the closed-loop reference system are characterized in this paper. Numerical simulation is provided to demonstrate the performance of the presented adaptive control scheme.

  12. Demonstration of Active Combustion Control

    Science.gov (United States)

    Lovett, Jeffrey A.; Teerlinck, Karen A.; Cohen, Jeffrey M.

    2008-01-01

    The primary objective of this effort was to demonstrate active control of combustion instabilities in a direct-injection gas turbine combustor that accurately simulates engine operating conditions and reproduces an engine-type instability. This report documents the second phase of a two-phase effort. The first phase involved the analysis of an instability observed in a developmental aeroengine and the design of a single-nozzle test rig to replicate that phenomenon. This was successfully completed in 2001 and is documented in the Phase I report. This second phase was directed toward demonstration of active control strategies to mitigate this instability and thereby demonstrate the viability of active control for aircraft engine combustors. This involved development of high-speed actuator technology, testing and analysis of how the actuation system was integrated with the combustion system, control algorithm development, and demonstration testing in the single-nozzle test rig. A 30 percent reduction in the amplitude of the high-frequency (570 Hz) instability was achieved using actuation systems and control algorithms developed within this effort. Even larger reductions were shown with a low-frequency (270 Hz) instability. This represents a unique achievement in the development and practical demonstration of active combustion control systems for gas turbine applications.

  13. Improvement of burst-mode control of piezoelectric transformer based DC/DC converter

    International Nuclear Information System (INIS)

    Burst-mode operation is adopted sometimes in piezoelectric transformer based converters for two major purposes: (1) to achieve voltage regulation in DC/DC converters and (2) to achieve dimming control in backlight inverters. Burst-mode control enables the converter to operate at a constant switching frequency as well as to maintain good efficiency at light load conditions. However, in practice, the piezoelectric transformer cannot instantly stop vibrating in the burst-mode due to its high quality factor. The delay in the output voltage change resulting from this behavior influences the accuracy of the regulation. This paper proposes a control strategy to make the piezoelectric transformer stop more quickly so as to enhance the accuracy of burst-mode control. The proposed method only modifies the control signal of the burst-mode driving circuit. The proposed control strategy is verified by experiments in a step-down 9 W DC/DC converter. (paper)

  14. Finite-time control of DC-DC buck converters via integral terminal sliding modes

    Science.gov (United States)

    Chiu, Chian-Song; Shen, Chih-Teng

    2012-05-01

    This article presents novel terminal sliding modes for finite-time output tracking control of DC-DC buck converters. Instead of using traditional singular terminal sliding mode, two integral terminal sliding modes are introduced for robust output voltage tracking of uncertain buck converters. Different from traditional sliding mode control (SMC), the proposed controller assures finite convergence time for the tracking error and integral tracking error. Furthermore, the singular problem in traditional terminal SMC is removed from this article. When considering worse modelling, adaptive integral terminal SMC is derived to guarantee finite-time convergence under more relaxed stability conditions. In addition, several experiments show better start-up performance and robustness.

  15. Spatio-temporal Control of Light Transmission through a Multimode Fiber with Strong Mode Coupling

    CERN Document Server

    Xiong, Wen; Bromberg, Yaron; Rotter, Stefan; Cao, Hui

    2016-01-01

    We experimentally generate and characterize the eigenstates of the Wigner-Smith time-delay matrix, called principal modes, in a multimode fiber with strong mode coupling. The unique spectral and temporal properties of principal modes enable a global control of the temporal dynamics of optical pulses transmitted through the fiber, despite random mode mixing. Our analysis reveals that the well-defined delay time of the eigenstates are formed by multi-path interference, which can be effectively manipulated by the spatial degrees of freedom of the input wavefront. This study is essential to controlling the dynamics of wave scattering, paving the way for coherent control of pulse propagation through complex media.

  16. Spatiotemporal Control of Light Transmission through a Multimode Fiber with Strong Mode Coupling

    Science.gov (United States)

    Xiong, Wen; Ambichl, Philipp; Bromberg, Yaron; Redding, Brandon; Rotter, Stefan; Cao, Hui

    2016-07-01

    We experimentally generate and characterize eigenstates of the Wigner-Smith time-delay matrix, called principal modes, in a multimode fiber with strong mode coupling. The unique spectral and temporal properties of principal modes enable global control of temporal dynamics of optical pulses transmitted through the fiber, despite random mode mixing. Our analysis reveals that well-defined delay times of the eigenstates are formed by multipath interference, which can be effectively manipulated by spatial degrees of freedom of input wave fronts. This study is essential to controlling dynamics of wave scattering, paving the way for coherent control of pulse propagation through complex media.

  17. Stabilization Controller Design for a class of Inverted Pendulums via Adaptive Fuzzy Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Heng Liu

    2013-07-01

    Full Text Available X–Z inverted pendulum is a new kind of inverted pendulum and it can move with the combination of the vertical and horizontal forces. This paper addresses  the control problem of X-Z inverted pendulum in the presents of system uncertainties and external disturbances, and an adaptive fuzzy sliding mode control approach is proposed. The fuzzy  system is used to approximate the system uncertainties and the complicated intermediate control functions in the backstepping control design. To update the parameters of the fuzzy system, a proper proportional-integral adaptation law is introduced.  Finally, simulation studies are done to show the stabilization of the X-Z inverted pendulum under the proposed method.

  18. Active Control of Fan Noise

    Institute of Scientific and Technical Information of China (English)

    Nobuhiko YAMASAKI; Hirotoshi TAJIMA

    2008-01-01

    In the wake-rotor interaction fan noise, a number of the interacting modes at the blade passing frequency (BPF)and its harmonics are generated which are prescribed by the number of stator and rotor blades etc. In the present study, the dominant mode is tried to be suppressed by the secondary sound from the loudspeaker actuators. One of the novel features of the present system is the adoption of the control board with the Field Programmable Gate Array (FPGA) hardware and the LabVIEW software to synchronize the circumferentially installed loudspeaker actuators with the relative location of rotational blades under arbitrary fan rotational speeds. The experiments were conducted under the conditions of three rotational speeds of 2004, 3150, and 4002 [rpm]. The reduction in the sound pressure level (SPL) was observed for all three rotational speeds. The sound pressure level at the BPF was reduced approximately 13 [dB] for 2004 [rpm] case, but not so large reduction was attained for other cases probably due to the inefficiency of the loudspeaker actuators at high frequencies

  19. ABOUT CONTROLLING OF SCIENTIFIC ACTIVITY

    Directory of Open Access Journals (Sweden)

    Mukhin V. V.

    2014-06-01

    Full Text Available We have selected the new area of controlling - scientific activity controlling. We consider some problems of development in this field, primarily the problem of selection of key performance indicators. It’s been founded that administrative measures stimulated the pursuit of a number of articles published in scientific journals hinders the development of science. Methodological errors - emphasis on citation indexes, impact factors, etc. - lead to wrong management decisions. As the experience of the UK, an expertise should be applied in the management of science. The article briefly discusses some of the drawbacks of the system of scientific specialties. It is proposed to expand research on the science of science and scientific activity controlling. We have also discussed the problems of controlling in applied research organizations

  20. A Feedforward-Feedback Interpretation of a Sliding Mode Control Law

    NARCIS (Netherlands)

    Monsees, Govert; George, Koshy; Scherpen, Jacquelien M.A.; Verhaegen, Michel

    1999-01-01

    In this paper we provide a feedforward-feedback interpretation of a sliding mode control scheme. Given a desired trajectory, the feedforward signal is generated using a stable inversion method, and the feedback signal includes the switching term of the sliding mode control law. In this manner, we in

  1. Transitions in Dynamo Modes Controlled by the Domain Aspect Ratio

    Science.gov (United States)

    Goudard, L.; Dormy, E.

    2007-12-01

    Magnetic fields of internal origin are observed on many planets in the solar system. The Sun itself acts as a dynamo. While these natural objects are very different in their composition, when it comes to dynamo modeling the governing equations are remarkably similar. One of the controlling parameters to distinguish between these objects is the aspect ratio of the convecting domain. Comparing the Sun to the Earth raises the issue of the nature of reversals. A challenging issue is to determine why the geomagnetic field reverses polarity on an irregular basis, whereas the Sun --which is a much larger object, governed by stronger nonlinearities-- reverses its magnetic polarity on a quasi-periodic timescale of 11 yrs. We use a three-dimensional Boussinesq model (the Parody code) to investigate the transition between these two types of behavior. We show that the aspect ratio of the convecting domain controls the nature of the dynamo field. We report a butterfly-like diagram at large aspect ratio, with magnetic activity near 30° of latitudes, which migrates with time toward the equator. We trace the existence of the dynamo wave solution at various aspect ratio and suggest possible consequences for the geomagnetic secular variation.

  2. Research on Grey Sliding Mode Control of Motor System of Fruit Harvesting Manipulator Joint

    Directory of Open Access Journals (Sweden)

    Jueping Bu

    2015-03-01

    Full Text Available The sliding mode control algorithm based on grey prediction theory is proposed in this study, aiming at the uncertainties in the servo system of fruit harvesting robot and the external disturbances that may affect the control quality of conventional sliding mode control algorithm. The proposed algorithm uses the grey theory ability to unknown information data to establish the grey model to the uncertainty and real-time compensate the unmodeled dynamics and the interference signal of system. Meanwhile, an improved reaching law direction is proposed to resist chattering and improve control accuracy. The simulation results show that the proposed sliding mode control algorithm effectively predicts and compensates the unmodeled dynamics and disturbances signal in the DC motor servo system of the fruit harvesting robot and improves the control precision of controller which provides the theoretical basis for the industrial application based on the grey prediction theory of sliding mode control algorithm.

  3. Avoidance of Tearing Mode Locking and Disruption with Electro-Magnetic Torque Introduced by Feedback-based Mode Rotation Control in DIII-D and RFX-mod

    Energy Technology Data Exchange (ETDEWEB)

    Okabayashi, M. [PPPL; Zanca, P. [Euratom-ENEA; Strait, E. J. [General Atomics

    2014-09-01

    Disruptions caused by tearing modes (TMs) are considered to be one of the most critical roadblocks to achieving reliable, steady-state operation of tokamak fusion reactors. Here we have demonstrated a very promising scheme to avoid such disruptions by utilizing the electro-magnetic (EM) torque produced with 3D coils that are available in many tokamaks. In this scheme, the EM torque to the modes is created by a toroidal phase shift between the externally-applied field and the excited TM fields, compensating for the mode momentum loss due to the interaction with the resistive wall and uncorrected error fields. Fine control of torque balance is provided by a feedback scheme. We have explored this approach in two vastly different devices and plasma conditions: DIII-D and RFX-mod operated in tokamak mode. In DIII-D, the plasma target was high βN plasmas in a non-circular divertor tokamak. In RFX-mod, the plasma was ohmically-heated plasma with ultralow safety factor in a circular limiter discharge of active feedback coils outside the thick resistive shell. The DIII-D and RFX-mod experiments showed remarkable consistency with theoretical predictions of torque balance. The application to ignition-oriented devices such as International Thermonuclear Experimental Reactor (ITER) would expand the horizon of its operational regime. The internal 3D coil set currently under consideration for edge localized mode suppression in ITER would be well suited to this purpose.

  4. Regulatory Mode Preferences for Autonomy Supporting versus Controlling Instructional Styles

    Science.gov (United States)

    Pierro, Antonio; Presaghi, Fabio; Higgins, Tory E.; Kruglanski, Arie W.

    2009-01-01

    Background: Three studies carried out in educational settings examined determinants of teacher's instructional styles and students' degree of satisfaction with the learning climates created by such styles. Aims: Based upon regulatory mode theory, Studies 1 and 2 tested the hypotheses that teachers' locomotion orientation will be positively…

  5. Application of attachment modes in the control of large space structures

    Science.gov (United States)

    Craig, Roy R., Jr.

    1989-01-01

    Various ways are examined to obtain reduced order mathematical models of structures for use in dynamic response analyses and in controller design studies. Attachment modes are deflection shapes of a structure subjected to specified unit load distributions. Attachment modes are frequently employed to supplement free-interface normal modes to improve the modeling of components (structures) employed in component mode synthesis analyses. Deflection shapes of structures subjected to generalized loads of some specified distribution and of unit magnitude can also be considered to be attachment modes. Several papers which were written under this contract are summarized herein.

  6. Optimized feedback control system modeling of resistive wall modes for burning plasmas experiments

    Science.gov (United States)

    Katsuro-Hopkins, Oksana Nikolaevna

    A numerical study of active feedback control system performance and optimization for tokamak Resistive Wall Modes (RWM) is the subject of this thesis. The ability to accurately model and predict the performance of an active MHD control systems is critical to present and future advanced confinement scenarios and fusion reactor design studies. The computer code VALEN has been designed to calculate the performance of a MHD feedback control system in an arbitrary geometry. The simulation of realistic effects in feedback systems, such as noise, time delays and filters is of particular importance. In this work realistic measurement noise analysis was added to VALEN and used to design the RWM feedback control amplifier power level for the DIII-D experiment. Modern control theory based on a state-space formulation obtained from VALEN was applied to design an Optimal Controller and Observer based on a reduced VALEN model. A quantitative low order model of the VALEN state space was derived from the high dimensional intrinsic state space structure of the VALEN using methods of a balanced realization and matched DC gain truncation. These techniques for the design of an optimal controller and optimal observer were applied to models of the DIII-D and ITER experiments and showed an order of magnitude reduction of the required control coil current and voltage in the presence of white noise as compared to a traditional, classical PID controller. This optimal controller for the ITER burning plasma experiment was robust from the no-wall pressure limit to a pressure value well above those achieved with a classical PID controller and could approach the ideal wall limit.

  7. Active control: Wind turbine model

    DEFF Research Database (Denmark)

    Bindner, H.

    1999-01-01

    validation as well as parameter estimation. The model includes a simple model of the structure of the turbine including tower and flapwise blade bending,a detailed model of the gear box and induction generator, a linearized aerodynamic model including modelling of induction lag and actuator and sensor models......This report is a part of the reporting of the work done in the project 'Active Control of Wind Turbines'. This project aim is to develop a simulation model for design of control systems for turbines with pitch control and to use that model to designcontrollers. This report describes the model...... developed for controller design and analysis. Emphasis has been put on establishment of simple models describing the dynamic behavior of the wind turbine in adequate details for controller design. This hasbeen done with extensive use of measurements as the basis for selection of model complexity and model...

  8. Super-twisting sliding mode control of torque and flux in permanent magnet synchronous machine drives

    DEFF Research Database (Denmark)

    Lascu, Christian; Boldea, Ion; Blaabjerg, Frede

    2013-01-01

    This paper investigates a permanent magnet synchronous motor drive controlled by a second-order variable structure control technique, known as the super-twisting sliding modes (STSM) control. The STSM controller is designed as a direct torque and flux controller and it works in the stator flux...

  9. Optimal nonlinear coherent mode transitions in Bose-Einstein condensates utilizing spatiotemporal controls

    Science.gov (United States)

    Hocker, David; Yan, Julia; Rabitz, Herschel

    2016-05-01

    Bose-Einstein condensates (BECs) offer the potential to examine quantum behavior at large length and time scales, as well as forming promising candidates for quantum technology applications. Thus, the manipulation of BECs using control fields is a topic of prime interest. We consider BECs in the mean-field model of the Gross-Pitaevskii equation (GPE), which contains linear and nonlinear features, both of which are subject to control. In this work we report successful optimal control simulations of a one-dimensional GPE by modulation of the linear and nonlinear terms to stimulate transitions into excited coherent modes. The linear and nonlinear controls are allowed to freely vary over space and time to seek their optimal forms. The determination of the excited coherent modes targeted for optimization is numerically performed through an adaptive imaginary time propagation method. Numerical simulations are performed for optimal control of mode-to-mode transitions between the ground coherent mode and the excited modes of a BEC trapped in a harmonic well. The results show greater than 99 % success for nearly all trials utilizing reasonable initial guesses for the controls, and analysis of the optimal controls reveals primarily direct transitions between initial and target modes. The success of using solely the nonlinearity term as a control opens up further research toward exploring novel control mechanisms inaccessible to linear Schrödinger-type systems.

  10. Active switching in metamaterials using polarization control of light

    CERN Document Server

    Xu, Hua

    2010-01-01

    We demonstrate on-demand control of localized surface plasmons in metamaterials by means of incident light polarization. An asymmetric mode, selectively excited by s-polarized light, interfere destructively with a bright element, thereby allowing the incident light to propagate at a fairly low loss, corresponding to electromagnetically induced transparency (EIT) in an atomic system. In contrast, a symmetric mode, excited by p-polarized light, directly couples with the incident light, which is analogous to the switch-off of EIT. The light polarization-dependent excitation of asymmetric and symmetric plasmon modes holds potential for active switching applications of plasmon hybridization.

  11. Use of active extracts of poplar buds against Penicillium italicum and possible modes of action.

    Science.gov (United States)

    Yang, Shuzhen; Liu, Limei; Li, Dongmei; Xia, Huan; Su, Xiaojun; Peng, Litao; Pan, Siyi

    2016-04-01

    Antifungal components, from poplar buds active fraction (PBAF) against Penicillium italicum, the causal agent of blue mold in citrus fruits, were identified and possible action modes were investigated. Pinocembrin, chrysin and galangin were determined as active components in PBAF, using HPLC and HPLC-MS analysis. The antifungal activity is stable at temperatures ranging from 4 °C to 100 °C and pH levels ranging from 4 to 8. In the presence of PBAF, the hyphae become shriveled, wrinkled and the cell membrane became seriously disrupted. Further investigation on cell permeability, nucleic acid content and alkaline phosphatase suggest that the cell membrane might be the target. Mycelial oxygen consumption and the respiration-related enzymatic activity of succinate dehydrogenase, malate dehydrogenase and ATPase were all inhibited by PBAF. We propose that PBAF is a potentially useful alternative for blue mold control and may act against P. italicum by interfering with respiration and disrupting the cell membrane. PMID:26593534

  12. Head-Positioning Control Using Virtual Resonant Modes in a Hard Disk Drive

    Science.gov (United States)

    Atsumi, Takenori

    In conventional control systems in hard disk drives, it is difficult to compensate for disturbances above the primary mechanical resonance. In this paper, a design method that uses a virtual resonant mode in head-positioning systems of hard disk drives was developed. The virtual resonant mode is a digital filter that works like a mechanical resonant mode. Using the proposed method, stable resonant modes in a control system can be designed with a high degree of accuracy to compensate for disturbances whose frequencies are higher than that of the primary mechanical resonance. Application of this method to a hard disk drive showed that it significantly suppresses disturbances beyond the primary mechanical resonance.

  13. A NEW SLIDING MODE CONTROL FOR A CLASS OF UNCERTAIN TIME-DELAY CHAOTIC SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    LI LI-XIANG; PENG HAI-PENG; GUAN BAO-ZHU; XU JIN-MING

    2001-01-01

    We propose a new sliding mode control scheme for a class of uncertain time-delay chaotic systems. It is shown that a linear time invariant system with the desired system dynamics is used as a reference model for the output of a time-delay chaotic system to track. A sliding mode controller is then designed to drive the output of the time-delay chaotic system to track the desired linear system. On the sliding mode, the output of the controlled time-delay chaotic system can behave like the desired linear system. A simulation example is given in support of the proposed control scheme.

  14. Constant Power Control of a Proton Exchange Membrane Fuel Cell through Adaptive Fuzzy Sliding Mode

    Directory of Open Access Journals (Sweden)

    Minxiu Yan

    2013-05-01

    Full Text Available Fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. The paper describes a mathematical model of proton exchange membrane fuel cells by analyzing the working mechanism of the proton exchange membrane fuel cell. Furthermore, an adaptive fuzzy sliding mode controller is designed for the constant power output of PEMFC system. Simulation results prove that adaptive fuzzy sliding mode control has better control effect than conventional fuzzy sliding mode control.

  15. Sliding mode pulse-width modulation technique for direct torque controlled induction motor drive

    Science.gov (United States)

    Bounadja, M.; Belarbi, A. W.; Belmadani, B.

    2010-05-01

    This paper presents a novel pulse-width modulation technique based sliding mode approach for direct torque control of an induction machine drive. Methodology begins with a sliding mode control of machine's torque and stator flux to generate the reference voltage vector and to reduce parameters sensitivity. Then, the switching control of the three-phase inverter is developed using sliding mode concept to make the system tracking reference voltage inputs. The main features of the proposed methodologies are the high tracking accuracy and the much easier implementation compared to the space vector modulation. Simulations are carried out to confirm the effectiveness of proposed control algorithms.

  16. A generalized regular form for multivariable sliding mode control

    Directory of Open Access Journals (Sweden)

    W. Perruquetti

    2001-01-01

    Full Text Available The paper shows how to compute a diffeomorphic state space transformation in order to put the initial mutivariable nonlinear model into an appropriate regular form. This form is an extension of the one proposed by Lukyanov and Utkin [9], and constitutes a guidance for a “natural” choice of the sliding surface. Then stabilization is achieved via a sliding mode strategy. In order to overcome the chattering phenomenon, a new nonlinear gain is introduced.

  17. Design and Demonstration of Emergency Control Modes for Enhanced Engine Performance

    Science.gov (United States)

    Liu, Yuan; Litt, Jonathan S.; Guo, Ten-Huei

    2013-01-01

    A design concept is presented for developing control modes that enhance aircraft engine performance during emergency flight scenarios. The benefits of increased engine performance to overall vehicle survivability during these situations may outweigh the accompanied elevated risk of engine failure. The objective involves building control logic that can consistently increase engine performance beyond designed maximum levels based on an allowable heightened probability of failure. This concept is applied to two previously developed control modes: an overthrust mode that increases maximum engine thrust output and a faster response mode that improves thrust response to dynamic throttle commands. This paper describes the redesign of these control modes and presents simulation results demonstrating both enhanced engine performance and robust maintenance of the desired elevated risk level.

  18. Effect of Pump Area on Lasing Modes in Active Random Media

    Institute of Scientific and Technical Information of China (English)

    XIE Ying-Mao; LIU Zheng-Dong

    2005-01-01

    @@ We investigate the effect of pump area on lasing modes in an active random medium. Considering the structure characteristics in a real experimental system, the random medium is divided into two regions, i.e. pump and non-pump areas. The dependence of lasing modes on the pump area is qualitatively explained by means of the model in which the lasing is ascribed to the interaction of the complex localized modes in the active random medium with local aperiodic quasi-structure with appropriate pump light. There exist different pump sizes for lasing with different modes. As the pump size decreases in this random system, the pump threshold of the lasing modes increases. There are different lasing modes in different excitation regions in this random system. This gives us some information about the dependence of lasing modes on pump areas in active random media.

  19. Methylphenidate remediates error-preceding activation of the default mode brain regions in cocaine addicted individuals

    Science.gov (United States)

    Matuskey, David; Luo, Xi; Zhang, Sheng; Morgan, Peter T.; Abdelghany, Osama; Malison, Robert T.; Li, Chiang-shan R.

    2013-01-01

    Many previous studies suggest the potential of psychostimulants in improving cognitive functioning. Our earlier pharmacological brain imaging study showed that intravenous methylphenidate (MPH) improves inhibitory control by altering cortico-striato-thalamic activations in cocaine dependent (CD) individuals. Here we provide additional evidence for the effects of MPH in restoring cerebral activations during cognitive performance. Ten CD individuals performed a stop signal task (SST) during functional magnetic resonance imaging (fMRI) in two sessions, in which either MPH (0.5 mg/Kg BW) or saline was administered intravenously. In the SST, a frequent go signal instructs participants to make a speeded response and a less frequent stop signal instructs them to withhold the response. Our previous work described increased activation of the precuneus/posterior cingulate cortex and ventromedial prefrontal cortex – regions of the default mode network (DMN) – before participants committed a stop error in healthy control but not CD individuals (Bednarski et al., 2011). The current results showed that, compared to saline, MPH restored error-preceding activations of DMN regions in CD individuals. The extent of the changes in precuneus activity was correlated with MPH-elicited increase in systolic blood pressure. These findings suggest that the influence of MPH on cerebral activations may extend beyond cognitive control and provide additional evidence warranting future studies to investigate the neural mechanisms and physiological markers of the efficacy of agonist therapy in cocaine dependence. PMID:23973363

  20. Robust Adaptive Neural Sliding Mode Approach for Tracking Control of a MEMS Triaxial Gyroscope

    Directory of Open Access Journals (Sweden)

    Juntao Fei

    2012-05-01

    Full Text Available In this paper, a neural network adaptive sliding mode control is proposed for an MEMS triaxial gyroscope with unknown system nonlinearities. An input‐output linearization technique is incorporated into the neural adaptive tracking control to cancel the nonlinearities, and the neural network whose parameters are updated from the Lyapunov approach is used to perform the linearization control law. The sliding mode control is utilized to\tcompensate the neural network’s approximation errors. The stability of the closed‐loop system can be guaranteed with the proposed adaptive neural sliding mode control. Numerical simulations are investigated to verify the effectiveness of the proposed adaptive neural sliding mode control scheme.

  1. Chatter free sliding mode control of a chaotic coal mine power grid with small energy inputs

    Institute of Scientific and Technical Information of China (English)

    Xu Yanqing; Jia Feng; Ma Caoyuan; Mao Jiasong; Zhang Shaowei

    2012-01-01

    An augmented proportional-integral sliding surface was designed for a sliding mode controller.A chatter free sliding mode control strategy for a chaotic coal mine power grid was developed.The stability of the control strategy was proven by Lyapunov stability theorem.The proposed sliding mode control strategy eliminated the chattering phenomenon by replacing the sign function with a saturation function,and by replacing the constant coefficients in the reaching law with adaptive ones.An immune genetic algorithm was used to optimize the parameters in the improved reaching.law.The cut-in time of the controllers was optimized to reduce the peak energy of their output.Simulations showed that the proposed sliding mode controller has good,chatter free performance.

  2. Chattering-free fuzzy sliding-mode control strategy for uncertain chaotic systems

    International Nuclear Information System (INIS)

    This paper proposes a chattering-free fuzzy sliding-mode control (FSMC) strategy for uncertain chaotic systems. A fuzzy logic control is used to replace the discontinuous sign function of the reaching law in traditional sliding-mode control (SMC), and hence a control input without chattering is obtained in the chaotic systems with uncertainties. Base on the Lyapunov stability theory, we address the design schemes of integration fuzzy sliding-mode control, where the reaching law is proposed by a set of linguistic rules and the control input is chattering free. The Genesio chaotic system is used to test the proposed control strategy and the simulation results show the FSMC not only can control the uncertain chaotic behaviors to a desired state without oscillator very fast, but also the switching function is smooth without chattering. This result implies that this strategy is feasible and effective for chaos control

  3. Decomposed Sliding Mode Control of the Drive with Interior Permanent Magnet Synchronous Motor and Flexible Coupling

    Directory of Open Access Journals (Sweden)

    Jan Vittek

    2013-01-01

    Full Text Available A decomposed sliding mode control of the drive with an interior permanent magnet synchronous motor and flexible coupling is presented. Decomposition exploits principles of vector control to divide motor into channel for control of magnetic flux and channel for control of torque separately. Sliding mode control principles are exploited to keep demanded value of magnetic flux and to control load angle in the presence of vibration modes and external disturbances. To obtain continues voltage as a control variable a smoothing integrator follows signum function in both channels. As a modification the switching governed by signum function is replaced by the high gain including rearrangement of the control system block diagram. The simulations indicate that the control system yields the desired robustness and further investigations are recommended.

  4. Robust motion control of oscillatory-base manipulators h∞-control and sliding-mode-control-based approaches

    CERN Document Server

    Toda, Masayoshi

    2016-01-01

    This book provides readers with alternative robust approaches to control design for an important class of systems characteristically associated with ocean-going vessels and structures. These systems, which include crane vessels, on-board cranes, radar gimbals, and a conductivity temperature and depth winch, are modelled as manipulators with oscillating bases. One design approach is based on the H-infinity control framework exploiting an effective combination of PD control, an extended matrix polytope and a robust stability analysis method with a state-dependent coefficient form. The other is based on sliding-mode control using some novel nonlinear sliding surfaces. The model demonstrates how successful motion control can be achieved by suppressing base oscillations and in the presence of uncertainties. This is important not only for ocean engineering systems in which the problems addressed here originate but more generally as a benchmark platform for robust motion control with disturbance rejection. Researche...

  5. Electrical Discharge Machining Flyback Converter using UC3842 Current Mode PWM Controller

    Directory of Open Access Journals (Sweden)

    Nazriah Mahmud

    2014-10-01

    Full Text Available This paper presents a current mode Pulse Width Modulation (PWM controlled Flyback converter using UC3842 for Electrical Discharge Machining current generator control circuit. Circuit simplicity and high efficiency can be achieved by a Flyback converter with current mode PWM controller. The behaviors of the system's operation is analyzed and discussed by varying the load resistance. Matlab sofware is used to simulate the Flyback converter where a prototype has been built and tested to verify it's performance.

  6. Piezo activated mode tracking system for widely tunable mode-hop-free external cavity mid-IR semiconductor lasers

    Science.gov (United States)

    Wysocki, Gerard (Inventor); Tittel, Frank K. (Inventor); Curl, Robert F. (Inventor)

    2010-01-01

    A widely tunable, mode-hop-free semiconductor laser operating in the mid-IR comprises a QCL laser chip having an effective QCL cavity length, a diffraction grating defining a grating angle and an external cavity length with respect to said chip, and means for controlling the QCL cavity length, the external cavity length, and the grating angle. The laser of claim 1 wherein said chip may be tuned over a range of frequencies even in the absence of an anti-reflective coating. The diffraction grating is controllably pivotable and translatable relative to said chip and the effective QCL cavity length can be adjusted by varying the injection current to the chip. The laser can be used for high resolution spectroscopic applications and multi species trace-gas detection. Mode-hopping is avoided by controlling the effective QCL cavity length, the external cavity length, and the grating angle so as to replicate a virtual pivot point.

  7. Optical mode control of surface-plasmon quantum cascade lasers

    Science.gov (United States)

    Moreau, V.; Bahriz, M.; Palomo, J.; Wilson, L. R.; Krysa, A. B.; Sirtori, C.; Austin, D. A.; Cockburn, J. W.; Roberts, J. S.; Colombelli, R.

    2007-04-01

    Surface-plasmon waveguides based on metallic strips can provide a two dimensional optical confinement. This concept has been successfully applied to quantum cascade lasers, processed as ridge waveguides, to demonstrate that the lateral extension of the optical mode can be influenced solely by the width of the device top contact. For devices operating at a wavelength of λ ≈7.5 μm, the room-temperature threshold current density was reduced from 6.3 kA/cm2 to 4.4 kA/cm2 with respect to larger devices with full top metallization.

  8. Novel Active Combustion Control Valve

    Science.gov (United States)

    Caspermeyer, Matt

    2014-01-01

    This project presents an innovative solution for active combustion control. Relative to the state of the art, this concept provides frequency modulation (greater than 1,000 Hz) in combination with high-amplitude modulation (in excess of 30 percent flow) and can be adapted to a large range of fuel injector sizes. Existing valves often have low flow modulation strength. To achieve higher flow modulation requires excessively large valves or too much electrical power to be practical. This active combustion control valve (ACCV) has high-frequency and -amplitude modulation, consumes low electrical power, is closely coupled with the fuel injector for modulation strength, and is practical in size and weight. By mitigating combustion instabilities at higher frequencies than have been previously achieved (approximately 1,000 Hz), this new technology enables gas turbines to run at operating points that produce lower emissions and higher performance.

  9. Nonsingular Terminal Sliding Mode Control of Uncertain Second-Order Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    Minh-Duc Tran

    2015-01-01

    Full Text Available This paper presents a high-performance nonsingular terminal sliding mode control method for uncertain second-order nonlinear systems. First, a nonsingular terminal sliding mode surface is introduced to eliminate the singularity problem that exists in conventional terminal sliding mode control. By using this method, the system not only can guarantee that the tracking errors reach the reference value in a finite time with high-precision tracking performance but also can overcome the complex-value and the restrictions of the exponent (the exponent should be fractional number with an odd numerator and an odd denominator in traditional terminal sliding mode. Then, in order to eliminate the chattering phenomenon, a super-twisting higher-order nonsingular terminal sliding mode control method is proposed. The stability of the closed-loop system is established using the Lyapunov theory. Finally, simulation results are presented to illustrate the effectiveness of the proposed method.

  10. Operation Modes and Control Schemes for Internet-Based Teleoperation System with Time Delay

    Institute of Scientific and Technical Information of China (English)

    曾庆军; 宋爱国

    2003-01-01

    Teleoperation system plays an important role in executing task under hazard environment. As the computer networks such as the Internet are being used as the communication channel of teleoperation system, varying time delay causes the overall system unstable and reduces the performance of transparency. This paper proposed twelve operation modes with different control schemes for teleoperation on the Internet with time delay. And an optimal operation mode with control scheme was specified for teleoperation with time delay, based on the tradeoff between passivity and transparency properties. It experimentally confirmed the validity of the proposed optimal mode and control scheme by using a simple one DOF master-slave manipulator system.

  11. DERIVATION AND INTEGRAL SLIDING MODE VARIABLE STRUCTURE CONTROL OF HYDRAULIC VELOCITY TRACKING SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Wei Jianhua; Guan Cheng

    2005-01-01

    The velocity tracking control of a hydraulic servo system is studied. Since the dynamics of the system are highly nonlinear and have large extent of model uncertainties, such as big changes in load and parameters, a derivation and integral sliding mode variable structure control scheme (DI-SVSC) is proposed. An integral controller is introduced to avoid the assumption that the derivative of desired signal must be known in conventional sliding mode variable structure control, a nonlinear derivation controller is used to weaken the chattering of system. The design method of switching function in integral sliding mode control, nonlinear derivation coefficient and controllers of DI-SVSC is presented respectively. Simulation shows that the control approach is of nice robustness and improves velocity tracking accuracy considerably.

  12. A new controller for the seni-active suspension system with magnetor heological dampers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new sliding mode controller for semi-active suspension system with magnetorheological (MR) damper is presented in this paper. In the proposed sliding mode controller, a semi-active suspension based on the skyhook damper system is chosen as the reference model to be followed, and the control law is so determined that the asymptotically stable error dynamics occurs between the controlled state and the reference model state. Numerical simulations are carried out to study the performance of the new sliding mode controller. The results show that the proposed controller yields almost perfect tracking to the reference model and has a high robustness against model parameter uncertainties and disturbances.

  13. Identification and stochastic control of helicopter dynamic modes

    Science.gov (United States)

    Molusis, J. A.; Bar-Shalom, Y.

    1983-01-01

    A general treatment of parameter identification and stochastic control for use on helicopter dynamic systems is presented. Rotor dynamic models, including specific applications to rotor blade flapping and the helicopter ground resonance problem are emphasized. Dynamic systems which are governed by periodic coefficients as well as constant coefficient models are addressed. The dynamic systems are modeled by linear state variable equations which are used in the identification and stochastic control formulation. The pure identification problem as well as the stochastic control problem which includes combined identification and control for dynamic systems is addressed. The stochastic control problem includes the effect of parameter uncertainty on the solution and the concept of learning and how this is affected by the control's duel effect. The identification formulation requires algorithms suitable for on line use and thus recursive identification algorithms are considered. The applications presented use the recursive extended kalman filter for parameter identification which has excellent convergence for systems without process noise.

  14. Active optics control development at the LBT

    Science.gov (United States)

    Ashby, David S.; Biddick, Christopher; Hill, John M.

    2014-07-01

    The Large Binocular Telescope (LBT) is built around two 8.4 m-diameter primary mirrors placed with a centerline separation of 14.4 m in a common altitude/azimuth mount. Each side of the telescope can utilize a deployable prime focus instrument; alternatively, the beam can be directed to a Gregorian instrument by utilizing a deployable secondary mirror. The direct-Gregorian beam can be intercepted and redirected to several bent-Gregorian instruments by utilizing a deployable tertiary mirror. Two of the available bent-Gregorian instruments are interferometers, capable of coherently combining the beams from the two sides of the telescope. Active optics can utilize as many as 26 linearly independent degrees of freedom to position the primary, secondary and tertiary mirrors to control optical collimation while the telescope operates in its numerous observing modes. Additionally, by applying differential forces at 160 locations on each primary mirror, active optics controls the primary mirror figure. The authors explore the challenges associated with collimation and primary mirror figure control at the LBT and outline the ongoing related development aimed at optimizing image quality and preparing the telescope for interferometric operations.

  15. DOUBLE-BOOST DC-AC CONVERTER WITH SLIDING-MODE CONTROL FOR PORTABLE AUDIO

    DEFF Research Database (Denmark)

    Bolten Maizonave, Gert; Andersen, Michael Andreas E.; Kjærgaard, Claus;

    2009-01-01

    The double-boost topology is studied for operation as a dc-ac converter and single stage audio amplifier. A sliding-mode controller is designed in order to achieve fast enough response for the whole audio frequency range. Symmetric, asymmetric and interleaved operation modes are analyzed....

  16. Influence of PWM Modes on Commutation Torque Ripples in Sensorless Brushless DC Motor Control System

    Institute of Scientific and Technical Information of China (English)

    ZHANGXiang-jun; CHENBo-shi; 等

    2001-01-01

    This paper introduces four PWM modes used in the sensorless brushless DC motor control system,analyzes their different influences on the commutation torque ripple in detail,and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC( BLDC) motors,Simulation and experimental results show that the selection is correct and practical.

  17. Quaternion-Based Tracking Control Law Design for Tracking Mode

    OpenAIRE

    Elbeltagy, A. M.; Elhalwagy, Y. Z.; Bayoumy, A. M.; A. M. Youssef

    2016-01-01

    Various control design techniques are model dependent. They typically require knowledge of the inertia matrix. There are major challenges for each proposed controller to cope with spacecraft mission objective in terms of pointing and jitter requirements. These challenges include sensitivity to noise effects and/or modeling errors, while others are sensitive to external torque disturbances, such as torques induced by solar radiation pressure. Robust controllers have been developed to mitigate ...

  18. Finite-Time Reentry Attitude Control Using Time-Varying Sliding Mode and Disturbance Observer

    Directory of Open Access Journals (Sweden)

    Xuzhong Wu

    2015-01-01

    Full Text Available This paper presents the finite-time attitude control problem for reentry vehicle with redundant actuators in consideration of planet uncertainties and external disturbances. Firstly, feedback linearization technique is used to cancel the nonlinearities of equations of motion to construct a basic mode for attitude controller. Secondly, two kinds of time-varying sliding mode control methods with disturbance observer are integrated with the basic mode in order to enhance the control performance and system robustness. One method is designed based on boundary layer technique and the other is a novel second-order sliding model control method. The finite-time stability analyses of both resultant closed-loop systems are carried out. Furthermore, after attitude controller produces the torque commands, an optimization control allocation approach is introduced to allocate them into aerodynamic surface deflections and on-off reaction control system thrusts. Finally, the numerical simulation results demonstrate that both of the time-varying sliding mode control methods are robust to uncertainties and disturbances without chattering phenomenon. Moreover, the proposed second-order sliding mode control method possesses better control accuracy.

  19. Modeling and control of distributed energy systems during transition between grid connected and standalone modes

    Science.gov (United States)

    Arafat, Md Nayeem

    Distributed generation systems (DGs) have been penetrating into our energy networks with the advancement in the renewable energy sources and energy storage elements. These systems can operate in synchronism with the utility grid referred to as the grid connected (GC) mode of operation, or work independently, referred to as the standalone (SA) mode of operation. There is a need to ensure continuous power flow during transition between GC and SA modes, referred to as the transition mode, in operating DGs. In this dissertation, efficient and effective transition control algorithms are developed for DGs operating either independently or collectively with other units. Three techniques are proposed in this dissertation to manage the proper transition operations. In the first technique, a new control algorithm is proposed for an independent DG which can operate in SA and GC modes. The proposed transition control algorithm ensures low total harmonic distortion (THD) and less voltage fluctuation during mode transitions compared to the other techniques. In the second technique, a transition control is suggested for a collective of DGs operating in a microgrid system architecture to improve the reliability of the system, reduce the cost, and provide better performance. In this technique, one of the DGs in a microgrid system, referred to as a dispatch unit , takes the additional responsibility of mode transitioning to ensure smooth transition and supply/demand balance in the microgrid. In the third technique, an alternative transition technique is proposed through hybridizing the current and droop controllers. The proposed hybrid transition control technique has higher reliability compared to the dispatch unit concept. During the GC mode, the proposed hybrid controller uses current control. During the SA mode, the hybrid controller uses droop control. During the transition mode, both of the controllers participate in formulating the inverter output voltage but with different

  20. Hybrid-impulsive second order sliding mode control: Lyapunov approach

    NARCIS (Netherlands)

    Shtessel, Y.; Glumineau, A.; Plestan, F.; Weiss, M.

    2013-01-01

    A perturbed nonlinear system of relative degree two controlled by discontinuous-impulsive feedbacks is studied. The hybrid-impulsive terms serve to drive instantaneously the system trajectories to the origin or to its small vicinity. In particular, impulsive-twisting control exhibits an uniform exac

  1. Gain-controlled erbium-doped fiber amplifier using mode-selective photonic lantern

    Science.gov (United States)

    Lopez-Galmiche, G.; Sanjabi Eznaveh, Z.; Antonio-Lopez, J. E.; Velazquez-Benitez, A. M.; Rodriguez-Asomoza, J.; Herrera-Piad, L. A.; Sanchez-Mondragon, J. J.; Gonent, C.; Sillard, P.; Li, G.; SchuÌlzgen, A.; Okonkwo, C.; Amezcua Correa, R.

    2016-02-01

    For the first time, we demonstrate the implementation of a core pumped few mode erbium amplifier utilizing a mode selective photonic lantern for spatial modal control of the pump light. This device is able to individually amplify the first six fiber modes with low differential modal gain. In addition, we obtained differential modal gain lower than 1 dB and signal gain of approximately 16.17 dB at λs = 1550 nm through forward pumping the LP21 modes at λp = 976 nm.

  2. Advances in the control of markov jump linear systems with no mode observation

    CERN Document Server

    Vargas, Alessandro N; do Val, João B R

    2016-01-01

    This brief broadens readers’ understanding of stochastic control by highlighting recent advances in the design of optimal control for Markov jump linear systems (MJLS). It also presents an algorithm that attempts to solve this open stochastic control problem, and provides a real-time application for controlling the speed of direct current motors, illustrating the practical usefulness of MJLS. Particularly, it offers novel insights into the control of systems when the controller does not have access to the Markovian mode.

  3. Two-stage pH Control Mode in Batch Fermentation of a Novel Bioflocculant from Corynebacterium Glutamicum

    Institute of Scientific and Technical Information of China (English)

    HE Ning; WU Xiao-jie; DENG Xu; LU Ying-hua; LI Qing-biao

    2004-01-01

    The effect of pH of the fermentation medium on cell growth and the production of a novel bioflocculant (named REA-11 ) by Corynebacterium glutamicum CCTCC M201005 were investigated. The maximum biomass (2.23 g/L) and flocculating activity (142.2 U/mL) were simultaneously obtained at the 14th hour when the pH value of the culture medium was maintained at 7.0 during the whole fermentation process. The production of REA-11 kept on a trend of increase till the later phase of fermentation process, which resulted in the ultimate flocculating activity of the culture broth to enhance to nearly 100 U/mL at pH 6.0. A twostage pH control mode was adopted in REA-11 production in which the pH value of the culture medium was controlled at 7.0 during the first 14 h, then decreased to 6.0 that was maintained until the end of the fermentation process. With the two-stage pH control mode, the maximum flocculating activity reached 178.8 U/mL which was 30% higher than that obtained under the condition of pH 7.0 and the biomass enhanced about 15%. Compared with the fermentation process without pH control, REA-11 production and cell growth via the two-stage pH control mode increased 80% and 25%, respectively.

  4. Study on the Nonsingular Problem of Fractional-Order Terminal Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Kening Li

    2013-01-01

    Full Text Available An improved type of control strategy combining the fractional calculus with nonsingular terminal sliding mode control named non-singular fractional terminal sliding mode control (NFOTSM is proposed for the nonlinear tire-road friction control system of vehicle in this paper. A fractional-order switching manifold is proposed, and the corresponding control law is formulated based on the Lyapunov stability theory to guarantee the sliding condition. The proposed controller ensures the finite time stability of the closed-loop system. Then, a terminal attractor is introduced to solve the singularity problem of fractional terminal sliding mode control (FOTSM. Finally, the performance of the NFOTSM is fully investigated compared with other related algorithms to find the effectiveness for the tire-road friction system. The results show that the NFOTSM has better performance than other related algorithms.

  5. Robustness-tracking control based on sliding mode and H∞ theory for linear servo system

    Institute of Scientific and Technical Information of China (English)

    TIAN Yan-feng; GUO Qing-ding

    2005-01-01

    A robustness-tracking control scheme based on combining H∞ robust control and sliding mode control is proposed for a direct drive AC permanent-magnet linear motor servo system to solve the conflict between tracking and robustness of the linear servo system. The sliding mode tracking controller is designed to ensure the system has a fast tracking characteristic to the command, and the H∞ robustness controller suppresses the disturbances well within the close loop( including the load and the end effect force of linear motor etc. ) and effectively minimizes the chattering of sliding mode control which influences the steady state performance of the system. Simulation results show that this control scheme enhances the track-command-ability and the robustness of the linear servo system, and in addition, it has a strong robustness to parameter variations and resistance disturbances.

  6. Adaptive fuzzy sliding mode control for synchronization of uncertain fractional order chaotic systems

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Tsung-Chih, E-mail: tclin@fcu.edu.tw [Department of Electronic Engineering, Feng-Chia University, Taichung, Taiwan (China); Lee, Tun-Yuan [Department of Electronic Engineering, Feng-Chia University, Taichung, Taiwan (China); Balas, Valentina E. [Aurel Vlaicu University of Arad, B-dul Revolutiei 77, 310130 Arad (Romania)

    2011-10-15

    Highlights: > We study uncertain fractional order chaotic systems synchronization. > Lyapunov synthesis is used to derive control law and adaptive laws. > Based on sliding mode control, chattering phenomena in the control effort can be reduced. - Abstract: This paper deals with chaos synchronization between two different uncertain fractional order chaotic systems based on adaptive fuzzy sliding mode control (AFSMC). With the definition of fractional derivatives and integrals, a fuzzy Lyapunov synthesis approach is proposed to tune free parameters of the adaptive fuzzy controller on line by output feedback control law and adaptive law. Moreover, chattering phenomena in the control efforts can be reduced. The sliding mode design procedure not only guarantees the stability and robustness of the proposed AFSMC, but also the external disturbance on the synchronization error can be attenuated. The simulation example is included to confirm validity and synchronization performance of the advocated design methodology.

  7. Automated adaptive sliding mode control scheme for a class of real complicated systems

    Indian Academy of Sciences (India)

    M Shahi; A H Mazinan

    2015-02-01

    A class of real complicated systems, including chemical reactions, biological systems, information processing, laser systems, electrical circuits, information exchange, brain activities modelling, secure communication and other related ones can be presented through nonlinear and non-identical hyper-chaotic systems. The main goal of the present investigation is to synchronize two non-identical hyperchaotic master/slave systems, which are given as the models of the complicated systems, based on the realization of an efficient automated adaptive sliding mode control scheme. In the research presented here, the mentioned systems need to be dealt with through the proposed control scheme, since two non-identical systems are completely synchronized. In one such case, the whole of the chosen states of the master and slave systems should be coincided after a few time steps, as long as the effect of the external disturbance, uncertainty and unknown parameters could truly be ignored. Due to the fact that the investigated hyper-chaotic systems have taken into consideration as the representation of a number of complicated processes under mentioned external disturbance, uncertainty and unknown parameters, the traditional control approaches cannot actually be realized, in satisfactory manners.With this purpose, the proposed control scheme has been designed to cope with synchronization error, in a reasonable amount of time, in order to drive applicable hyper-chaotic systems. Consequently, the performance of the proposed control scheme is considered and verified through the numerical simulations.

  8. Open-phase operating modes of power flow control topologies in a Smart Grid Distribution Network

    Science.gov (United States)

    Astashev, M. G.; Novikov, M. A.; Panfilov, D. I.; Rashitov, P. A.; Remizevich, T. V.; Fedorova, M. I.

    2015-12-01

    The power flow regulating circuit node in an alternating current system is reviewed. The circuit node is accomplished based on a thyristor controlled phase angle regulator (TCPAR) with controlled thyristor switch. Research results of the individual phase control of the output voltage for the TCPAR are presented. Analytical expressions for the overvoltage factor calculation in the thyristor switch circuit for open-phase operating modes are received. Based on evaluation of overvoltage in operational and emergency modes, the implementability conditions of the individual phase control of the output voltage are determined. Under these conditions, maximal performance and complete controllability are provided.

  9. Certainty equivalence adaptation combined with super-twisting sliding-mode control

    Science.gov (United States)

    Barth, A.; Reichhartinger, M.; Wulff, K.; Horn, M.; Reger, J.

    2016-09-01

    In this paper, a Lyapunov-based control concept is presented that combines variable structure and adaptive control. The considered system class consists of nonlinear single input systems which are affected by matched structured and unstructured uncertainties. Resorting to the certainty equivalence principle, the controller exploits advantages of both the sliding-mode and the adaptive control methodology. It is demonstrated that the gains of the discontinuous control action may be reduced remarkably when compared with pure sliding-mode-based approaches. The efficiency of the presented concept is demonstrated in detail, using results of numerical simulations.

  10. Second Order Sliding Mode Control with Prescribed Convergence Law for Electro-Hydraulic Drives

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben Ole; Pedersen, Henrik C.;

    2013-01-01

    This paper discusses the application of second order sliding modes for position tracking control of electro-hydraulic valve-cylinder drives (VCD’s). The target is to introduce increased tracking- and transient performance compared to conventional linear approaches, without extending the number...... approach, and that control chattering is eliminated without introducing a boundary layer, normally seen in first order sliding mode controlled systems....... of tuning parameters. The proposed controller utilizes basic component knowledge commonly available from data sheets, as well as pressure-, valve position-, piston position- and velocity measurements. Results demonstrate improved position tracking- and transient performance, compared to a linear control...

  11. The impact of a firm's internal control mechanisms on the choice of innovation mode

    Institute of Scientific and Technical Information of China (English)

    LIU Xinmin; LI Yuan; SU Zhongfeng; FENG Jinlu

    2007-01-01

    A finn's internal control mechanisms may have a significant influence on the choice of innovation mode. Therefore, based on the research on the internal control mechanisms of companies, we developed a model to explore the relationship between a finn's internal control mechanisms and the choice of innovation mode. Using a sample of 585 Chinese finns, this study tests the proposed model. Results show that strategic control has a positive relationship with radical innovation, but a negative relationship with incremental innovation, while financial control has a negative relationship with radical innovation, but a positive relationship with incremental innovation.

  12. Some Remarks on the Boundedness and Convergence Properties of Smooth Sliding Mode Controllers

    Institute of Scientific and Technical Information of China (English)

    Wallace Moreira Bessa

    2009-01-01

    Conventional sliding mode controllers are based on the assumption of switching control, but a well-known drawback of such controllers is the chattering phenomenon. To overcome the undesirable chattering effects, the discontinuity in the control law can be smoothed out in a thin boundary layer neighboring the switching surface. In this paper, rigorous proofs of the boundedness and convergence properties of smooth sliding mode controllers are presented. This result corrects flawed conclusions previously reached in the literature. An illustrative example is also presented in order to confirm the convergence of the tracking error vector to the defined bounded region.

  13. Control on Housing Segregation:Housing Modes and Public Policies

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>1. Housing segregation:advocating or controlling?The phenomenon of housing segregation has become more and more obvious in Chinese cities in recent years; however, there is no agreement on whether it should

  14. Seamless Mode Switching for Shared Control of Semiautonomous Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Whether it be a crew station, the Shuttle Remote Manipulator System (SRMS), an unmanned ground rover (UGV) or air vehicle (UAV), or teams thereof, the controllers...

  15. Intelligent Control of Quadrotor Unmanned Helicopter in Hovering Mode

    OpenAIRE

    Neda Shamshiri; Abbas Chatraei

    2015-01-01

    A Quadrotor helicopter is an unmanned aerial vehicle (UAV). This vehicle has attracted lots of researchers’ attention because of its unique abilities such as being an under-actuated system, vertical take-off and landing, spot movement, more degree of freedom (DOF) and military and non- military functions. Because of nonlinear and complex dynamic, modeling and controlling this vehicle is one of the most challenging areas in control engineering. In this paper modeling of a Quadrotor will be des...

  16. Adaptive Robust Sliding Mode Vibration Control of a Flexible Beam Using Piezoceramic Sensor and Actuator: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Ruo Lin Wang

    2014-01-01

    Full Text Available This paper presents an experimental study of an adaptive robust sliding mode control scheme based on the Lyapunov’s direct method for active vibration control of a flexible beam using PZT (lead zirconate titanate sensor and actuator. PZT, a type of piezoceramic material, has the advantages of high reliability, high bandwidth, and solid state actuation and is adopted here in forms of surface-bond patches for vibration control. Two adaptive robust sliding mode controllers for vibration suppression are designed: one uses a discontinuous bang-bang robust compensator and the other uses a smooth compensator with a hyperbolic tangent function. Both controllers guarantee asymptotic stability, as proved by the Lyapunov’s direct method. Experimental results verified the effectiveness and the robustness of both adaptive sliding mode controllers. However, from the experimental results, the bang-bang robust compensator causes small-magnitude chattering because of the discontinuous switching actions. With the smooth compensator, vibration is quickly suppressed and no chattering is induced. Furthermore, the robustness of the controllers is successfully demonstrated with ensured effectiveness in vibration control when masses are added to the flexible beam.

  17. A Digital Controller for Active Aeroelastic Controls

    OpenAIRE

    Ueda, Tetsuhiko; MUROTA, Katsuichi; 上田, 哲彦; 室田, 勝一

    1989-01-01

    A high-speed digital controller for aeroelastic controls was designed and made. The purpose was to minimize adverse phase lag which is inevitably produced by the CPU time of digital processing. The delay deteriorates control performances on rather rapid phenomena like aircraft flutter. With fix-point operation the controller realized 417 microseconds of throughput time including the A/D and D/A conversion. This corresponds to a high sampling rate of 2.4kHz. The controller furnishes two channe...

  18. Altered default mode network activity in patient with anxiety disorders: An fMRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Xiaohu [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China) and Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: xhzhao999@263.net; Wang Peijun [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: tongjipjwang@vip.sina.com; Li Chunbo [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: licb@mail.tongji.edu.cn; Hu Zhenghui [Department of Electrical and Engineering, Hong Kong University of Science and Technology, Hong Kong (China)], E-mail: eezhhu@ust.hk; Xi Qian [Imaging Department of Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: 96125007@sina.com.cn; Wu Wenyuan [Department of Psychiatry, Tong Ji Hospital of Tong Ji University, Shanghai 200065 (China)], E-mail: wuwy@mail.tongji.edu.cn; Tang Xiaowei [Bio-X lab, Department of Physics, Zhe Jiang University, Hangzhou 310027 (China)], E-mail: tangxw@zju.edu.cn

    2007-09-15

    Anxiety disorder, a common mental disorder in our clinical practice, is characterized by unprovoked anxiety. Medial prefrontal cortex (MPFC) and posterior cingulate cortex (PCC), which closely involved in emotional processing, are critical regions in the default mode network. We used functional magnetic resonance imaging (fMRI) to investigate whether default mode network activity is altered in patients with anxiety disorder. Ten anxiety patients and 10 healthy controls underwent fMRI while listening to emotionally neutral words alternating with rest (Experiment 1) and threat-related words alternating with emotionally neutral words (Experiment 2). In Experiment 1, regions of deactivation were observed in patients and controls. In Experiment 2, regions of deactivation were observed only in patients. The observed deactivation patterns in the two experiments, which included MPFC, PCC, and inferior parietal cortex, were similar and consistent with the default model network. Less deactivation in MPFC and greater deactivation in PCC were observed for patients group comparing to controls in Experiment 1. Our observations suggest that the default model network is altered in anxiety patients and dysfunction in MPFC and PCC may play an important role in anxiety psychopathology.

  19. Robust fuzzy control for stochastic Markovian jumping systems via sliding mode method

    Science.gov (United States)

    Chen, Bei; Jia, Tinggang; Niu, Yugang

    2016-07-01

    This paper considers the problem of sliding mode control for stochastic Markovian jumping systems by means of fuzzy method. The Takagi-Sugeno (T-S) fuzzy stochastic model subject to state-dependent noise is presented. A key feature in this work is to remove the restricted condition that each local system model had to share the same input channel, which is usually assumed in some existing results. The integral sliding surface is constructed for every mode and the connections among various sliding surfaces are established via a set of coupled matrices. Moreover, the present sliding mode controller including the transition rates of modes can cope with the effect of Markovian switching. It is shown that both the reachability of sliding surfaces and the stability of sliding mode dynamics can be ensured. Finally, numerical simulation results are given.

  20. Control of self-excitation mode in thermoacoustic system using heat phase adjuster

    Science.gov (United States)

    Kido, Aiko; Sakamoto, Shin-ichi; Taga, Kazusa; Watanabe, Yoshiaki

    2016-07-01

    The capability of a heat phase adjuster (HPA) to control the resonance mode in a loop-tube-type thermoacoustic system by locally heating the outside is experimentally investigated. It is shown that the HPA enables the resonance mode of the tube to shift to lower modes with higher thermoacoustic conversion efficiency, thus significantly enhancing the energy conversion efficiency. The transition of the resonance mode due to the stepwise change in the input electric power to the HPA is also investigated. As a result, it is demonstrated that the resonance mode changes with the temperature and a threshold exists for the HPA temperature at which the transition is induced. These results suggest the possibility of externally controlling a loop-tube-type thermoacoustic system.

  1. Study on VMI Inventory Control Mode based on the Third-Party Logistics

    OpenAIRE

    Haoxiong Yang; Jindan Li

    2014-01-01

    Adding the third party logistics enterprises between the suppliers and the retailers is a kind of the development of VMI mode, in this mode; inventory pressure is transferred to the third party logistics enterprise. In view of this situation, the VMI inventory control model which treats total inventory control costs as the objective function is built based on from four dimensions: the inventory holding costs, the fixed delivery costs, replenishment costs and customer waiting costs. After solv...

  2. Active load control using microtabs

    Science.gov (United States)

    Yen, Dora Te-Lun

    2001-11-01

    Micro-electro-mechanical (MEM) translational tabs are introduced for enhancing and controlling the aerodynamic loading on lifting surfaces. These microtabs are mounted near the trailing edge of lifting surfaces, retract and extend approximately normal to the surface and have a maximum deployment height on the order of the boundary-layer thickness. Deployment of the device effectively modifies the camber distribution of the lifting surface and hence, the lift generated. The effect of the microtabs on lift is shown to be as powerful as conventional control surfaces with lift changes of 30%--50% in the linear range of the lift curve using a tab with a height of 1% of airfoil chord placed at 5% of chord upstream of the trailing edge on the lower surface. A multi-disciplinary approach incorporating aspects of experimental and computational aerodynamics, mechanical design and microfabrication techniques has been taken to develop and test a "proof of concept" model. Flow simulations, using a Reynolds-averaged Navier Stokes solver, have been conducted to optimize the size and placement of the devices based on trailing edge volume constraints. Numerical and experimental wind tunnel results are in good agreement, and both confirm that these micro-scale devices create macro-scale changes in aerodynamic loading. Application of this rather simple but innovative lift control system based on microfabrication techniques introduces a robust, dynamic control device and will allow for the miniaturization of conventional high lift and control systems. The result is a significant reduction in typical control system weight, complexity and cost. Also due to the minute size of these tabs, their activation and response times are much faster than that of conventional trailing edge devices. The "proof of concept" tab design, fabrication techniques, computational and experimental setup, and test results using a representative airfoil are presented in this research. (For more information, see

  3. 76 FR 14795 - Special Conditions: Gulfstream Model GVI Airplane; Electronic Flight Control System Mode...

    Science.gov (United States)

    2011-03-18

    ...; Electronic Flight Control System Mode Annunciation. AGENCY: Federal Aviation Administration (FAA), DOT... electronic flight control system. The applicable airworthiness regulations do not contain adequate or...). Novel or Unusual Design Features The GVI will have a fly-by-wire electronic flight control system....

  4. Controlling Spiral Waves by Modulations Resonant with the Intrinsic System Mode

    Institute of Scientific and Technical Information of China (English)

    XIAO Jing-Hua; HU Gang; HU Bam-Bi

    2004-01-01

    We investigate the spiral wave control in the two-dimensional complex Ginzburg-Landau equation. External drivings which are not resonant with spiral waves but with intrinsic system modes are used to successfully annihilate spiral waves and direct the system to various target states. The novel control mechanism is intuitively explained and the richness and flexibility the control results are emphasized.

  5. New Gain Controllable Resistor-less Current-mode First Order Allpass Filter and its Application

    Directory of Open Access Journals (Sweden)

    W. Jaikla

    2012-04-01

    Full Text Available New first order allpass filter (APF in current mode, constructed from 2 CCCCTAs and grounded capacitor, is presented. The current gain and phase shift can be electronically /orthogonally controlled. Low input and high output impedances are achieved which make the circuit to be easily cascaded to the current-mode circuit without additional current buffers. The operation of the proposed filter has been verified through simulation results which confirm the theoretical analysis. The application example as current-mode quadrature oscillator with non-interactive current control for both of oscillation condition and oscillation frequency is included to show the usability of the proposed filter.

  6. H∞ Observer-Based Sliding Mode Control for Uncertain Stochastic Systems with Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Peng Zhang

    2013-01-01

    Full Text Available The paper is concerned with sliding mode control for uncertain time-delay systems subjected to input nonlinearity and stochastic perturbations. Using the sliding mode control, a robust law is derived to guarantee the reachability of the sliding surface in a finite time interval. The sufficient conditions on asymptotic stability of the error system and sliding mode dynamics with disturbance attenuation level are presented in terms of linear matrix inequalities (LMIs. Finally, an example is provided to illustrate the efficiency and effectiveness of the proposed method.

  7. Mode shifting in school travel mode: examining the prevalence and correlates of active school transport in Ontario, Canada

    OpenAIRE

    Buliung Ron; Faulkner Guy; Wong Bonny Yee-Man; Irving Hyacinth

    2011-01-01

    Abstract Background Studies examining the correlates of school transport commonly fail to make the distinction between morning and afternoon school trips. The purpose of this study was to examine the prevalence and correlates of mode shift from passive in the morning to active in the afternoon among elementary and secondary school students in Ontario, Canada. Methods Data were derived from the 2009 cycle of the Ontario Student Drug Use and Health Survey (OSDUHS). 3,633 students in grades 7 th...

  8. Fuzzy sliding mode control of a doubly fed induction generator for wind energy conversion

    Directory of Open Access Journals (Sweden)

    A. Meroufel

    2013-12-01

    Full Text Available In this paper we present a nonlinear control using fuzzy sliding mode for wind energy conversion system based on a doubly-fed induction generator (DFIG supplied by an AC-AC converter. In the first place, we carried out briefly a study of modeling on the whole system. In order to control the power flowing between the stator of the DFIG and the grid, a proposed control design uses fuzzy logic technique is applied for implementing a fuzzy hitting control law to remove completely the chattering phenomenon on a conventional sliding mode control. The use of this method provides very satisfactory performance for the DFIG control, and the chattering effect is also reduced by the fuzzy mode. The machine is tested in association with a wind turbine. Simulations results are presented and discussed for the whole system.

  9. Decoupled thermal control for space station furnace facility using sliding mode techniques

    Science.gov (United States)

    Jackson, Mark E.; Shtessel, Yuri B.

    1996-03-01

    The Space Station Furnace Facility (SSFF) provides the necessary core systems to operate various material processing furnaces. The Thermal Control System (TCS) is defined as one of the core systems and its function is to collect excess heat from furnaces and to provide precise cold temperature control of components and of certain furnace zones. Physical interconnection of parallel thermal control subsystems through a common pump implies the description of the whole TCS by coupled nonlinear differential equations in flow and pressure. The paper formulates the system equations and develops the sliding mode controllers that cause the interconnected subsystems to operate in the local sliding modes, resulting in control system invariance to interaction disturbances. The desired de-coupled flow rate profile tracking is achieved by optimization of the local linear sliding mode equations. Extensive digital simulation results are presented to show the flow rate tracking robustness and invariance to plant nonlinearities and variations of the pump pressure supplied to the controlled subsystems.

  10. Sliding-Mode Synchronization Control for Uncertain Fractional-Order Chaotic Systems with Time Delay

    Directory of Open Access Journals (Sweden)

    Haorui Liu

    2015-06-01

    Full Text Available Specifically setting a time delay fractional financial system as the study object, this paper proposes a single controller method to eliminate the impact of model uncertainty and external disturbances on the system. The proposed method is based on the stability theory of Lyapunov sliding-mode adaptive control and fractional-order linear systems. The controller can fit the system state within the sliding-mode surface so as to realize synchronization of fractional-order chaotic systems. Analysis results demonstrate that the proposed single integral, sliding-mode control method can control the time delay fractional power system to realize chaotic synchronization, with strong robustness to external disturbance. The controller is simple in structure. The proposed method was also validated by numerical simulation.

  11. The Dynamics and Sliding Mode Control of Multiple Cooperative Welding Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Bin Zi

    2012-08-01

    Full Text Available This paper deals with the design, dynamic modelling and sliding mode control of multiple cooperative welding robot manipulators (MWRMs. The MWRMs can handle complex tasks that are difficult or even impossible for a single manipulator. The kinematics and dynamics of the MWRMs are studied on the basis of the Denavit‐Hartenberg and Lagrange method. Following that, considering the MWRM system with nonlinear and unknown disturbances, a non‐singular terminal sliding mode control strategy is designed. By means of the Lyapunov function, the stability of the controller is proved. Simulation results indicate that the good control performance of the MWRMs is achieved by the non‐singular terminal sliding mode controller, which also illustrates the correctness of the dynamic modelling and effectiveness of the proposed control strategy.

  12. Optimization of Markov jump linear system with controlled modes jump probabilities

    Institute of Scientific and Technical Information of China (English)

    Yankai XU; Xi CHEN

    2009-01-01

    The optimal control of a Markov jump linear quadratic model with controlled jump probabilities of modes is investigated.Two kinds of mode control policies,i.e.,open-loop control policy and closed-loop control pol-icy,are considered.Using the concepts of policy iteration and performance potential,the sufficient condition needed for the optimal closed-loop control policy to per-form better than the optimal open-loop control policy is proposed.The condition is helpful for the design of an optimal controller.Furthermore,an efficient algorithm to construct a closed-loop control policy,which is better than the optimal open-loop control policy,is given with policy iteration.

  13. Research of Compound Control for DC Motor System Based on Global Sliding Mode Disturbance Observer

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-01-01

    Full Text Available Aiming at the problems of modeling errors, parameter variations, and load moment disturbances in DC motor control system, one global sliding mode disturbance observer (GSMDO is proposed based on the global sliding mode (GSM control theory. The output of GSMDO is used as the disturbance compensation in control system, which can improve the robust performance of DC motor control system. Based on the designed GSMDO in inner loop, one compound controller, composed of a feedback controller and a feedforward controller, is proposed in order to realize the position tracking of DC motor system. The gains of feedback controller are obtained by means of linear quadratic regulator (LQR optimal control theory. Simulation results present that the proposed control scheme possesses better tracking properties and stronger robustness against modeling errors, parameter variations, and friction moment disturbances. Moreover, its structure is simple; therefore it is easy to be implemented in engineering.

  14. The simplex method for nonlinear sliding mode control

    Directory of Open Access Journals (Sweden)

    Bartolini G.

    1998-01-01

    Full Text Available General nonlinear control systems described by ordinary differential equations with a prescribed sliding manifold are considered. A method of designing a feedback control law such that the state variable fulfills the sliding condition in finite time is based on the construction of a suitable simplex of vectors in the tangent space of the manifold. The convergence of the method is proved under an obtuse angle condition and a way to build the required simplex is indicated. An example of engineering interest is presented.

  15. Investigation of Timing to Switch Control Mode in Powered Knee Prostheses during Task Transitions.

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    Full Text Available Current powered prosthetic legs require switching control modes according to the task the user is performing (e.g. level-ground walking, stair climbing, walking on slopes, etc.. To allow prosthesis users safely and seamlessly transition between tasks, it is critical to determine when to switch the prosthesis control mode during task transitions. Our previous study defined critical timings for different types of task transitions in ambulation; however, it is unknown whether it is the unique timing that allows safe and seamless transitions. The goals of this study were to (1 systematically investigate the effects of mode switch timing on the prosthesis user's performance in task transitions, and (2 identify appropriate timing to switch the prosthesis control mode so that the users can seamlessly transition between different locomotion tasks. Five able-bodied (AB and two transfemoral (TF amputee subjects were tested as they wore a powered knee prosthesis. The prosthesis control mode was switched manually at various times while the subjects performed different types of task transitions. The subjects' task transition performances were evaluated by their walking balance and success in performing seamless task transitions. The results demonstrated that there existed a time window within which switching the prosthesis control mode neither interrupted the subjects' task transitions nor disturbed their walking balance. Therefore, the results suggested the control mode switching of a lower limb prosthesis can be triggered within an appropriate time window instead of a specific timing or an individual phase. In addition, a generalized criterion to determine the appropriate mode switch timing was proposed. The outcomes of this study could provide important guidance for future designs of neurally controlled powered knee prostheses that are safe and reliable to use.

  16. Control study of pulmonary surfactant combined with CPAP and BIPAP ventilation modes respectively in treatment of neonatal NRDS

    Institute of Scientific and Technical Information of China (English)

    Yao Liu

    2016-01-01

    Objective:To analyze the differences in effect of pulmonary surfactant combined with CPAP and BIPAP ventilation modes respectively in treatment of neonatal NRDS.Methods:A total of 50 cases of children with neonatal respiratory distress syndrome (NRDS) born and receiving treatment in our hospital from August 2012 to January 2015 were selected as research subjects and randomly divided into observation group and control group, each with 25 cases. Control group received pulmonary surfactant combined with CPAP ventilation mode treatment, observation group received pulmonary surfactant combined with BIPAP ventilation mode treatment, and then differences in blood gas indicators and mechanical ventilation parameters, pulmonary artery pressure, endothelin and nitric oxide levels, blood coagulation and anticoagulation indicators and protein expression levels of CD24, TNF-α, IL-6 and IL-17A of two groups after treatment were compared.Results:PaO2, PH value and oxygenation index of observation group after treatment were higher than those of control group, and PaCO2, positive end-expiratory pressure, peak inspiratory pressure and inspired oxygen concentration were lower than those of control group; pulmonary artery pressure and EF-1 level of observation group after treatment were lower than those of control group, and NO level was higher than that of control group; PC, TPS and AT-Ⅲ levels of observation group after treatment were higher than those of control group, and D-D and vWF levels were lower than those of control group; protein expression of CD24 and IL-6 of observation group after treatment were lower than those of control group, and protein expression of TNF-α and IL-17A were higher than those of control group.Conclusion:Pulmonary surfactant combined with BIPAP ventilation mode treatment of children with NRDS can effectively optimize ventilation function and realize homeostasis, and it has active clinical significance.

  17. Augmented Adaptive Control of a Wind Turbine in the Presence of Structural Modes

    Science.gov (United States)

    Frost, Susan A.; Balas, Mark J.; Wright, Alan D.

    2010-01-01

    Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will want to develop methods to operate in the presence of these modes. Accurate models of the dynamic characteristics of new wind turbines are often not available due to the complexity and expense of the modeling task, making wind turbines ideally suited to adaptive control. In this paper, we develop theory for adaptive control with rejection of disturbances in the presence of modes that inhibit the controller. We use this method to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the interference of certain structural modes in feedback. The control objective is accomplished by collectively pitching the turbine blades. The adaptive pitch controller for Region 3 is compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller.

  18. Inductor Current Sampled Feedback Control of Chaos in Current-Mode Boost Converter

    Institute of Scientific and Technical Information of China (English)

    Bo-Cheng Bao; Jian-Ping Xu; Yan Liang

    2008-01-01

    A chaos control strategy for chaotic current-mode boost converter is presented by using inductor current sampled feedback control technique. The quantitative analysis of control mechanism is performed by establishing a discrete alterative map of the controlled system. The stability criterion, feedback gain, and corresponding critical duty ratio are obtained from the eigenvalue of the map. The simulation results verify the theoretical analysis results of the control strategy.

  19. Finite element models applied in active structural acoustic control

    OpenAIRE

    Oude Nijhuis, Marco H.H.; de Boer; Rao, Vittal S.

    2002-01-01

    This paper discusses the modeling of systems for active structural acoustic control. The finite element method is applied to model structures including the dynamics of piezoelectric sensors and actuators. A model reduction technique is presented to make the finite element model suitable for controller design. The reduced structural model is combined with an acoustic model which uses the radiation mode concept. For a test case consisting of a rectangular plate with one piezo patch the model re...

  20. A Sliding Mode Control for Uncertain Time-delay Systems

    Institute of Scientific and Technical Information of China (English)

    WU Jun-sheng; WENG Zheng-xin; TIAN Zuo-hua; SHI Song-jiao

    2008-01-01

    By means of the feasibility of some linear matrix inequalities (LMIs), delay dependeat sufficient condition is derived for the existence of a linear sliding surface, which guarantees quadratic stability of the reduced-order equivalent system restricted to the sliding surface. And a reaching motion controller is proposed. A numerical simulation shows the effectiveness of the approach.

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

    Directory of Open Access Journals (Sweden)

    Ricardo Carvalhal

    2007-01-01

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

  2. Finite time control for MIMO nonlinear system based on higher-order sliding mode.

    Science.gov (United States)

    Liu, Xiangjie; Han, Yaozhen

    2014-11-01

    Considering a class of MIMO uncertain nonlinear system, a novel finite time stable control algorithm is proposed based on higher-order sliding mode concept. The higher-order sliding mode control problem of MIMO nonlinear system is firstly transformed into finite time stability problem of multivariable system. Then continuous control law, which can guarantee finite time stabilization of nominal integral chain system, is employed. The second-order sliding mode is used to overcome the system uncertainties. High frequency chattering phenomenon of sliding mode is greatly weakened, and the arbitrarily fast convergence is reached. The finite time stability is proved based on the quadratic form Lyapunov function. Examples concerning the triple integral chain system with uncertainty and the hovercraft trajectory tracking are simulated respectively to verify the effectiveness and the robustness of the proposed algorithm. PMID:25277626

  3. Active structural control with stable fuzzy PID techniques

    CERN Document Server

    Yu, Wen

    2016-01-01

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

  4. Progress in analytical methods to predict and control azimuthal combustion instability modes in annular chambers

    Science.gov (United States)

    Bauerheim, M.; Nicoud, F.; Poinsot, T.

    2016-02-01

    Longitudinal low-frequency thermoacoustic unstable modes in combustion chambers have been intensively studied experimentally, numerically, and theoretically, leading to significant progress in both understanding and controlling these acoustic modes. However, modern annular gas turbines may also exhibit azimuthal modes, which are much less studied and feature specific mode structures and dynamic behaviors, leading to more complex situations. Moreover, dealing with 10-20 burners mounted in the same chamber limits the use of high fidelity simulations or annular experiments to investigate these modes because of their complexity and costs. Consequently, for such circumferential acoustic modes, theoretical tools have been developed to uncover underlying phenomena controlling their stability, nature, and dynamics. This review presents recent progress in this field. First, Galerkin and network models are described with their pros and cons in both the temporal and frequency framework. Then, key features of such acoustic modes are unveiled, focusing on their specificities such as symmetry breaking, non-linear modal coupling, forcing by turbulence. Finally, recent works on uncertainty quantifications, guided by theoretical studies and applied to annular combustors, are presented. The objective is to provide a global view of theoretical research on azimuthal modes to highlight their complexities and potential.

  5. Two alternative modes for diffuse pollution control in Wuhan City Zoo

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Pollution in urban zoos arises from diffuse and small point sources.However,its control has received little attention in past decades.Online and offline modes of ecological engineering technology were designed to control pollution from small point and diffuse sources in Wuhan City Zoo.China.Their characteristics and performances were investigated in sixteen runoff events from 2003 to 2005.The results showed that the two modes both improved runoff water quality and had high retention rates for water and pollutants.In the outflows,the event mean concentrations (EMCs) of total suspended solids (TSS),chemical oxygen demand (COD),total nitrogen (TN) and total phosphorus (TP) were reduced by 88%,59%,46% and 71% for the online mode,and those were 77%,42%,50% and 66% for the offline mode.The annual retention rates of pollutant loads for the online mode were 94.9%-98.5% in the three study years;those for the offline mode were 70.59%-86.4%.Based on calculation.the online mode was able to store the runoff of 66.7 mm rainfall completely,and the offline mode could store that of 31.3 mm rainfall.In addition,the online mode can provide an effective way for rainwater utilization and good habitats for aquatic wildlives,and has an excellent aesthetics value for recreationsal pastimes.The offline mode can save land resources and may be an effective and economical measure for diffuse pollution control in urban areas.

  6. Integral Sliding Mode Control Design for Electronic Throttle Valve System

    OpenAIRE

    Shibly Ahmed AL-Samarraie; Alaq Sabah Badri; Mustafa H. Mishary

    2015-01-01

    One of the major components in an automobile engine is the throttle valve part. It is used to keep up with emissions and fuel efficiency low. Design a control system to the throttle valve is newly common requirement trend in automotive technology. The non-smoothness nonlinearity in throttle valve model are due to the friction model and the nonlinear spring, the uncertainty in system parameters and non-satisfying the matching condition are the main obstacles when designing a throttle plate con...

  7. Amplitudes of High-Degree p-Modes in the Quiet and Active Sun

    OpenAIRE

    Burtseva, O.; Tripathy, S.C.; Hill, F.; Kholikov, S.; Raouafi, N. -E.; Lindsey, C.

    2009-01-01

    We investigate mode amplitudes in the active and quiet Sun in both maximum and minimum phases of the solar activity cycle. We confirm previous studies showing that p-mode amplitudes at solar minimum are higher than at solar maximum. We mask active regions of a certain magnetic field strength and compare the masked and unmasked acoustic power. After applying the masks, the preliminary analysis indicates that the amplitude decreases over all degrees during solar minimum, compared to the unmaske...

  8. Control and dynamic competition of bright and dark lasing states in active nanoplasmonic metamaterials

    CERN Document Server

    Wuestner, Sebastian; Pusch, Andreas; Renn, Fabian; Tsakmakidis, Kosmas L; Hess, Ortwin

    2011-01-01

    Active nanoplasmonic metamaterials support bright and dark modes that compete for gain. Using a Maxwell-Bloch approach incorporating Langevin noise we study the lasing dynamics in an active nano-fishnet structure. We report that lasing of the bright negative-index mode is possible if the higher-Q dark mode is discriminated by gain, spatially or spectrally. The nonlinear competition during the transient phase is followed by steady-state emission where bright and dark modes can coexist. We analyze the influence of pump intensity and polarization and explore methods for mode control.

  9. Design Intelligent PID like Fuzzy Sliding Mode Controller for Spherical Motor

    Directory of Open Access Journals (Sweden)

    Farzin Matin

    2014-04-01

    Full Text Available The minimum rule base Proportional Integral Derivative (PID Fuzzy Sliding Mode Controller (SMC with application to spherical motor is presented in this research. The popularity of PID Fuzzy Sliding Mode Controller can be attributed to their robust performance in a wide range of operating conditions and partly to their functional simplicity. The process of setting of PID Fuzzy Sliding Mode Controller can be determined as an optimization task. Over the years, use of intelligent strategies for tuning of these controllers has been growing especially in nonlinear and uncertain systems. Proportional Integral Derivative methodology has three inputs and if any input is described with seven linguistic values, and any rule has three conditions, we will need 343 rules. It is too much work to write 343 rules and have lots of problem to design embedded control system e.g., Field Programmable Gate Array (FPGA. In this research the PID-like fuzzy controller can be constructed as a parallel structure of a PD-like fuzzy controller and a conventional PI controller to have the minimum rule base and good trajectory follow disturbance to control of spherical motor. However Sliding Mode Controller is work based on cancelling decoupling and nonlinear terms of dynamic parameters for each direction of three degree of freedom spherical motor, this controller is work based on motor dynamic model and this technique is highly sensitive to the knowledge of all parameters of nonlinear spherical motor’s dynamic equation which caused to challenge in uncertain system. This research is used to reduce or eliminate the Sliding Mode Controller problem based on minimum rule base fuzzy logic theory to control of three degrees of freedom spherical motor system and testing of the quality of process control in the simulation environment of MATLAB/SIMULINK Simulator.

  10. Adaptive Control of Linear Modal Systems Using Residual Mode Filters and a Simple Disturbance Estimator

    Science.gov (United States)

    Balas, Mark; Frost, Susan

    2012-01-01

    Flexible structures containing a large number of modes can benefit from adaptive control techniques which are well suited to applications that have unknown modeling parameters and poorly known operating conditions. In this paper, we focus on a direct adaptive control approach that has been extended to handle adaptive rejection of persistent disturbances. We extend our adaptive control theory to accommodate troublesome modal subsystems of a plant that might inhibit the adaptive controller. In some cases the plant does not satisfy the requirements of Almost Strict Positive Realness. Instead, there maybe be a modal subsystem that inhibits this property. This section will present new results for our adaptive control theory. We will modify the adaptive controller with a Residual Mode Filter (RMF) to compensate for the troublesome modal subsystem, or the Q modes. Here we present the theory for adaptive controllers modified by RMFs, with attention to the issue of disturbances propagating through the Q modes. We apply the theoretical results to a flexible structure example to illustrate the behavior with and without the residual mode filter.

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

    Directory of Open Access Journals (Sweden)

    Yan Ren

    2013-01-01

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

  12. Frequency-shaped and observer-based discrete-time sliding mode control

    CERN Document Server

    Mehta, Axaykumar

    2015-01-01

    It is well established that the sliding mode control strategy provides an effective and robust method of controlling the deterministic system due to its well-known invariance property to a class of bounded disturbance and parameter variations. Advances in microcomputer technologies have made digital control increasingly popular among the researchers worldwide. And that led to the study of discrete-time sliding mode control design and its implementation. This brief presents, a method for multi-rate frequency shaped sliding mode controller design based on switching and non-switching type of reaching law. In this approach, the frequency dependent compensator dynamics are introduced through a frequency-shaped sliding surface by assigning frequency dependent weighing matrices in a linear quadratic regulator (LQR) design procedure. In this way, the undesired high frequency dynamics or certain frequency disturbance can be eliminated. The states are implicitly obtained by measuring the output at a faster rate than th...

  13. Model-Free Adaptive Fuzzy Sliding Mode Controller Optimized by Particle Swarm for Robot Manipulator

    Directory of Open Access Journals (Sweden)

    Amin Jalali

    2013-05-01

    Full Text Available The main purpose of this paper is to design a suitable control scheme that confronts the uncertainties in a robot. Sliding mode controller (SMC is one of the most important and powerful nonlinear robust controllers which has been applied to many non-linear systems. However, this controller has some intrinsic drawbacks, namely, the chattering phenomenon, equivalent dynamic formulation, and sensitivity to the noise. This paper focuses on applying artificial intelligence integrated with the sliding mode control theory. Proposed adaptive fuzzy sliding mode controller optimized by Particle swarm algorithm (AFSMC-PSO is a Mamdani’s error based fuzzy logic controller (FLS with 7 rules integrated with sliding mode framework to provide the adaptation in order to eliminate the high frequency oscillation (chattering and adjust the linear sliding surface slope in presence of many different disturbances and the best coefficients for the sliding surface were found by offline tuning Particle Swarm Optimization (PSO. Utilizing another fuzzy logic controller as an impressive manner to replace it with the equivalent dynamic part is the main goal to make the model free controller which compensate the unknown system dynamics parameters and obtain the desired control performance without exact information about the mathematical formulation of model.

  14. Design of a Sliding Mode Controller for Two-Wheeled Balancing Robot

    Directory of Open Access Journals (Sweden)

    Ehsan Abbas nejad

    2014-10-01

    Full Text Available Nowadays, the control of mechanical systems with fewer inputs than outputs (Under-actuated systems has become a challenging problem for control engineers. Two-wheeled balancing robots is one of the appealing examples of this category. This type of robot contains two parallel wheels and an inverted pendulum. In this research, designing of controller have been investigated for flat surfaces. For controller design, the extract dynamics of the system has been achieved based on Kane's method. Then for the two-wheeled balancing robot, one sliding mode controller has been designed for yaw angle, and another sliding mode controller has been designed to control both position and pitch angle based on a proposed sliding surface. The main feature of the proposed controllers is that all of controllers have been designed based on the nonlinear dynamics of system. Also, considering the limits of uncertainties while designing systems, the robustness of controllers have been increased. The common problem of sliding mode control is chattering phenomenon that has been greatly reduced using saturation function instead of sign function. Simulation results comparision of the designed controller with a LQR controller, validates the effectiveness of the proposed controller.

  15. Two-mode dynamics in pulse-modulated control systems

    DEFF Research Database (Denmark)

    Zhusubaliyev, Z.T.; Yanochkina, O.O.; Mosekilde, Erik;

    2010-01-01

    Pulse-modulated converter systems play an important role in modern power electronics. Systems of this type also deserve considerable theoretical interest because of the complex interplay they exhibit between ordinary (smooth) bifurcations and so-called border-collision bifurcations generated by the...... as an example the paper provides a survey of three new mechanisms of torus bifurcation that can be observed in pulse-modulated control systems. The paper concludes with a discussion of the influence that operation in the torus regimes will have on the efficiency of the converter...

  16. Travel Mode and Physical Activity at Sydney University

    OpenAIRE

    Chris Rissel; Ding Ding; Corinne Mulley

    2013-01-01

    How staff and students travel to university can impact their physical activity level. An online survey of physical activity and travel behaviour was conducted in early November 2012 to inform planning of physical activity and active travel promotion programs at the University of Sydney, Australia as part of the “Sit Less, Move More” sub-committee of the Healthy University Initiative, and as baseline data for evaluation. There were 3,737 useable responses, 60% of which were from students. Four...

  17. Control of external kink modes near the ideal wall limit using Kalman filtering and optimal control techniques

    International Nuclear Information System (INIS)

    We report on the first experimental demonstration of feedback suppression of rotating external kink modes near the ideal wall limit in a tokamak using Kalman filtering to discriminate n = 1 kink mode amplitude from background MHD noise. Kalman filtering was observed to suppress the kink over a broad range of feedback phase angles between the sensed mode and applied control field. This suppression is accomplished with no excitation of higher frequencies under feedback as was observed in previous experiments using simple lead-lag loop compensation. In order to achieve the highest plasma pressure limits in ITER, resistive wall kink mode stabilization is also required. A novel resistive wall mode Kalman filter and feedback controller designed using model reduction and optimal control theory and employing only proportional gain have been designed for ITER allowing operation up to 86% of the ideal wall limit using the present design external control coils. We find an order of magnitude reduction of the required control coil current and voltage in the presence of white noise from the no-wall limit to the optimal feedback system performance limit as compared with a traditional, classical controller. (author)

  18. Coordinated control for regulation/protection mode-switching of ducted rockets

    Science.gov (United States)

    Qi, Yiwen; Bao, Wen; Zhao, Jun; Chang, Juntao

    2014-05-01

    This study is concerned with the coordinated control problem for regulation/protection mode-switching of a ducted rocket, in order to obtain the maximum system performance while ensuring safety. The proposed strategy has an inner/outer loop control structure which decomposes the contradiction between performance and safety into two modes of regulation and protection. Specifically, first, the mathematical model including the actuator (gas regulating system) and the plant (ducted rocket engine) is introduced. Second, taking the inlet buzz for instance, the ducted rocket coordinated control problem for thrust regulation and inlet buzz limit protection is formulated and discussed. Third, to solve the problem, based on the main inner loop, a limit protection controller (outer loop) design method is developed utilizing a linear quadratic optimal control technique, and a coordinated control logic is then presented. At last, the whole coordinated control strategy is applied to the ducted rocket control model, and simulation results demonstrate its effectiveness.

  19. EEG alpha activity reflects motor preparation rather than the mode of action selection

    Directory of Open Access Journals (Sweden)

    Marie-Pierre eDeiber

    2012-08-01

    Full Text Available Alpha-band activity (8-13 Hz is suppressed by sensory stimulation and movements, modulated by attention, working memory and mental tasks and may be sensitive to higher motor control functions. The aim of the present study was to examine alpha oscillatory activity during the preparation of simple left or right finger movements, contrasting the external and internal mode of action selection. Three preparation conditions were examined using a precueing paradigm with S1 as the preparatory and S2 as the imperative cue: Full, laterality instructed by S1; Free, laterality freely selected and None, laterality instructed by S2. Time-frequency analysis was performed in the alpha frequency range during the S1-S2 interval, and alpha motor-related amplitude asymmetries (MRAA were also calculated. The significant MRAA during the Full and Free conditions indicated effective external and internal motor response preparation. In the absence of specific motor preparation (None, a posterior alpha power decrease (event-related desynchronization, ERD dominated, reflecting the main engagement of attentional resources. In Full and Free motor preparation, posterior alpha ERD was accompanied by a midparietal alpha power increase (event-related synchronization, ERS, suggesting a concomitant inhibition of task-irrelevant visual activity. In both Full and Free motor preparation, analysis of alpha power according to MRAA amplitude revealed two types of functional activation patterns: 1 a motor alpha pattern, with predominantly midparietal alpha ERS and large MRAA corresponding to lateralized motor activation/visual inhibition and 2 an attentional alpha pattern, with dominating right posterior alpha ERD and small MRAA reflecting visuospatial attention. The present results suggest that alpha oscillatory patterns do not resolve the selection mode of action, but rather distinguish separate functional strategies of motor preparation. 

  20. Common oscillatory modes in geomagnetic activity and climate variability and their phase relations

    International Nuclear Information System (INIS)

    Complete text of publication follows. Oscillatory modes with period of approximately 8 years were detected in monthly time series of geomagnetic activity aa-index, North Atlantic Oscillation index and near-surface air temperature from several mid-latitude European locations. Instantaneous phases of the modes underwent synchronization analysis and their statistically significant phase coherence, beginning from 1950's, has been observed.

  1. Active thermal figure control for the TOPS II primary mirror

    Science.gov (United States)

    Angel, Roger; Kang, Tae; Cuerden, Brian; Guyon, Olivier; Stahl, Phil

    2007-09-01

    TOPS (Telescope to Observe Planetary Systems) is the first coronagraphic telescope concept designed specifically to take advantage of Guyon's method of Phase Induced Amplitude Apodization PIAA).1 The TOPS primary mirror may incorporates active figure control to help achieve the desired wavefront control to approximately 1 angstrom RMS accurate across the spectral bandwidth. Direct correction of the primary figure avoids the need for a separate small deformable mirror. Because of Fresnel propagation, correction at a separate surface can introduce serious chromatic errors unless it is precisely conjugated to the primary. Active primary control also reduces complexity and mass and increases system throughput, and will likely enable a full system test to the 10-10 level in the 1 g environment before launch. We plan to use thermal actuators with no mechanical disturbance, using radiative heating or cooling fingers distributed inside the cells of a honeycomb mirror. The glass would have very small but finite coefficient of expansion of ~ 5x10 -8/C. Low order modes would be controlled by front-to-back gradients and high order modes by local rib expansion and contraction. Finite element models indicate that for a mirror with n cells up to n Zernike modes can be corrected to better than 90% fidelity, with still higher accuracy for the lower modes. An initial demonstration has been made with a borosilicate honeycomb mirror. Interferometric measurements show a single cell influence function with 300 nm stroke and ~5 minute time constant.

  2. Raman gain induced mode evolution and on-demand coupling control in whispering-gallery-mode microcavities.

    Science.gov (United States)

    Yang, Xu; Özdemir, Şahin Kaya; Peng, Bo; Yilmaz, Huzeyfe; Lei, Fu-Chuan; Long, Gui-Lu; Yang, Lan

    2015-11-16

    Waveguide-coupled optical resonators have played an important role in a wide range of applications including optical communication, sensing, nonlinear optics, slow/fast light, and cavity QED. In such a system, the coupling regimes strongly affect the resonance feature in the light transmission spectra, and hence the performance and outcomes of the applications. Therefore it is crucial to control the coupling between the waveguide and the microresonator. In this work, we investigated a fiber-taper coupled whispering-gallery-mode microresonator system, in which the coupling regime is traditionally controlled by adjusting the distance between the resonator and the fiber-taper mechanically. We propose and experimentally demonstrate that by utilizing Raman gain one can achieve on-demand control of the coupling regime without any mechanical movement in the resonator system. Particularly, the application of Raman gain is accompanied by Q enhancement. We also show that with the help of Raman gain control, the transitions between various coupling regimes can affect the light transmission spectra so as to provide better resolvability and signal amplification. This all-optical approach is also suitable for monolithically integrated and packaged waveguide-resonator systems, whose coupling regime is fixed at the time of manufacturing. It provides an effective route to control the light transmission in a waveguide-couple resonator system without mechanically moving individual optical components. PMID:26698440

  3. Integral Sliding Mode Control Strategy of D-STATCOM for Unbalanced Load Compensation under Various Disturbances

    OpenAIRE

    Mingchao Xia; Yanhui Mao

    2013-01-01

    Control strategies of D-STATCOM for unbalanced load compensation under internal and external disturbances were discussed. Linear control strategies do not have a satisfactory dynamic performance and become invalid under internal or external disturbances. To guarantee a good precision and robustness, a control strategy combining input-output feedback linearization technique with integral sliding mode control (ISMC) method was applied to D-STATCOM for unbalanced load compensation. The strategy ...

  4. Model Reference Sliding Mode Control of Small Helicopter X.R.B based on Vision

    OpenAIRE

    Wei Wang; Kenzo Nonami; Yuta Ohira

    2008-01-01

    This paper presents autonomous control for indoor small helicopter X.R.B. In case of natural disaster like earthquake, a MAV (Micro Air Vehicle) which can fly autonomously will be very effective for surveying the site and environment in dangerous area or narrow space, where human cannot access safely. In addition, it will be helpful to prevent secondary disaster. This paper describes vision based autonomous hovering control, guidance control for X.R.B by model reference sliding mode control.

  5. PRIMARY SIDE DETECTION AND PEAK CURRENT MODE CONTROL IN FLYBACK CONVERTER

    Institute of Scientific and Technical Information of China (English)

    Fang Jian; Lu Zhiping; Yang Jian; Li Zhaoji

    2004-01-01

    A new cycle-by-cycle control flyback converter with primary side detection and peak current mode control is proposed and its dynamic characteristics are analyzed. The flyback converter is verified by the OrCAD simulator. The main advantages of this converter over the conventional one are simplicity, small size, rapid regulating and no sensing control signals over the isolation barrier. The circuit is suitable for digital control implementations.

  6. Sliding mode control for Lorentz-augmented spacecraft hovering around elliptic orbits

    Science.gov (United States)

    Huang, Xu; Yan, Ye; Zhou, Yang; Zhang, Hua

    2014-10-01

    A Lorentz spacecraft is an electrostatically charged space vehicle that could actively modulate its surface charge to generate Lorentz force as it moves through the planetary magnetic field. The induced Lorentz force provides propellantless electromagnetic propulsion for orbital maneuvering, such as spacecraft hovering that the chaser thrusts continuously to create an equilibrium state at the desired position relative to the target. Due to the fact that the direction of Lorentz force is determined by the local magnetic field and the velocity of the spacecraft with respect to the local magnetic field, which does not necessarily coincide with that of the required control acceleration for hovering, thus, in most cases, the Lorentz force works as a means of auxiliary propulsion to reduce the expenditure of fuel onboard. And that is why it is called Lorentz-augmented hovering. A dynamical model for Lorentz-augmented hovering around elliptic orbits is developed based upon the assumption that the Earth's magnetic field could be modeled as a tilted dipole that corotates with Earth. Fuel-optimal open-loop control laws are then derived based on the proposed dynamical model, presenting the optimal trajectories of the required specific charge of Lorentz spacecraft and the thruster-generated control acceleration. Considering the external disturbances that may drift the desired hovering position, a closed-loop integral sliding mode controller is also designed to guarantee the tracking of optimal control trajectories, ensuring the robustness of the system against perturbations. Numerical simulations are presented to analyze the characteristics of Lorentz-augmented hovering around eccentric orbits and the results substantiate the validity of the proposed open-loop and closed-loop control methods.

  7. Flight Simulator Evaluation of Enhanced Propulsion Control Modes for Emergency Operation

    Science.gov (United States)

    Litt, Jonathan, S; Sowers, T.; Owen, A., Karl; Fulton, Christopher, E.; Chicatelli, Amy, K.

    2012-01-01

    This paper describes piloted evaluation of enhanced propulsion control modes for emergency operation of aircraft. Fast Response and Overthrust modes were implemented to assess their ability to help avoid or mitigate potentially catastrophic situations, both on the ground and in flight. Tests were conducted to determine the reduction in takeoff distance achievable using the Overthrust mode. Also, improvements in Dutch roll damping, enabled by using yaw rate feedback to the engines to replace the function of a stuck rudder, were investigated. Finally, pilot workload and ability to handle the impaired aircraft on approach and landing were studied. The results showed that improvement in all aspects is possible with these enhanced propulsion control modes, but the way in which they are initiated and incorporated is important for pilot comfort and perceived benefit.

  8. Adaptive Output Feedback Sliding Mode Control for Complex Interconnected Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Van Van Huynh

    2015-01-01

    Full Text Available We extend the decentralized output feedback sliding mode control (SMC scheme to stabilize a class of complex interconnected time-delay systems. First, sufficient conditions in terms of linear matrix inequalities are derived such that the equivalent reduced-order system in the sliding mode is asymptotically stable. Second, based on a new lemma, a decentralized adaptive sliding mode controller is designed to guarantee the finite time reachability of the system states by using output feedback only. The advantage of the proposed method is that two major assumptions, which are required in most existing SMC approaches, are both released. These assumptions are (1 disturbances are bounded by a known function of outputs and (2 the sliding matrix satisfies a matrix equation that guarantees the sliding mode. Finally, a numerical example is used to demonstrate the efficacy of the method.

  9. Placebo-controlled randomized clinical trial on the immunomodulating activities of low- and high-dose bromelain after oral administration - new evidence on the antiinflammatory mode of action of bromelain

    OpenAIRE

    Müller, Silke; März, Reinhard; Schmolz, Manfred; Drewelow, Bernd; Eschmann, Klaus; Meiser, Peter

    2013-01-01

    In a randomized controlled multiple cross-over trial, the effect of a single application of 1000 and 3000 F.I.P. bromelain on 6 cytokines, of male healthy volunteers was studied. The analysis of cytokines (Interferon gamma, IL-2, IL-6, IL8, IL-10, IL13 and MCP-1) was performed with the TrueCulture(tm) whole-blood culture system (EDI GmbH). With a single dose of 3000 F. I. P. bromelain, IFNgamma was found to be significantly stimulated in the afternoon hours compared to placebo (p = 0.043; Mix...

  10. Sliding mode control for multi-agent systems under a time-varying topology

    Science.gov (United States)

    Dong, Lijing; Chai, Senchun; Zhang, Baihai; Kiong Nguang, Sing

    2016-07-01

    This paper addresses the tracking problem of a class of multi-agent systems under uncertain communication environments which has been modelled by a finite number of constant Laplacian matrices together with their corresponding scheduling functions. Sliding mode control method is applied to solve this nonlinear tracking problem under a time-varying topology. The controller of each tracking agent has been designed by using only its own and neighbours' information. Sufficient conditions for the existence of a sliding mode control tracking strategy have been provided by the solvability of linear matrix inequalities. At the end of this work, numerical simulations are employed to demonstrate the effectiveness of the proposed sliding mode control tracking strategy.

  11. Adaptive sliding mode control of tethered satellite deployment with input limitation

    Science.gov (United States)

    Ma, Zhiqiang; Sun, Guanghui

    2016-10-01

    This paper proposes a novel adaptive sliding mode tension control method for the deployment of tethered satellite, where the input tension limitation is taken into account. The underactuated governing equations of the tethered satellites system are firstly derived based on Lagrangian mechanics theory. Considering the fact that the tether can only resist axial stretching, the tension input is modelled as input limitation. New adaptive sliding mode laws are addressed to guarantee the stability of the tethered satellite deployment with input disturbance, meanwhile to eliminate the effect of the limitation features of the tension input. Compared with the classic control strategy, the newly proposed adaptive sliding mode control law can deploy the satellite with smaller overshoot of the in-plane angle and implement the tension control reasonably and effectively in engineering practice. The numerical results validate the effectiveness of the proposed methods.

  12. Variable structure control with sliding mode prediction for discrete-time nonlinear systems

    Institute of Scientific and Technical Information of China (English)

    Lingfei XIAO; Hongye SU; Xiaoyu ZHANG; Jian CHU

    2006-01-01

    A new variable structure control algorithm based on sliding mode prediction for a class of discrete-time nonlinear systems is presented. By employing a special model to predict future sliding mode value, and combining feedback correction and receding horizon optimization methods which are extensively applied on predictive control strategy, a discrete-time variable structure control law is constructed. The closed-loop systems are proved to have robustness to uncertainties with unspecified boundaries. Numerical simulation and pendulum experiment results illustrate that the closed-loop systems possess desired performance, such as strong robustness, fast convergence and chattering elimination.

  13. Adaptive Multivariable Super-Twisting Sliding Mode Controller and Disturbance Observer Design for Hypersonic Vehicle

    Directory of Open Access Journals (Sweden)

    Wenru Fan

    2016-01-01

    Full Text Available A multivariable super-twisting sliding mode controller and disturbance observer with gain adaptation, chattering reduction, and finite time convergence are proposed for a generic hypersonic vehicle where the boundary of aerodynamic uncertainties exists but is unknown. Firstly, an input-output linearization model is constructed for the purpose of controller design. Then, the sliding manifold is designed based on the homogeneity theory. Furthermore, an integrated adaptive multivariable super-twisting sliding mode controller and disturbance observer are designed in order to achieve the tracking for step changes in velocity and altitude. Finally, some simulation results are provided to verify the effectiveness of the proposed method.

  14. Robust Adaptive Control Design for Rotorcraft Unmanned Aerial Vehicles Based on Sliding Mode Approach

    Institute of Scientific and Technical Information of China (English)

    郭建川; 鲜斌

    2014-01-01

    This paper presents a nonlinear robust control design method for a generic rotorcraft unmanned aerial ve-hicle (RUAV). The control objective is to let the RUAV track some pre-defined time-varying position and heading trajectories. The proposed controller employs feedback linearization process to realize the dynamic decoupling control and applies adaptive sliding mode control to compensate for the parametric uncertainties and external disturbances. The global asymptotical stability is proved via stability analysis. Compared with the cascaded controller, the proposed controller demonstrates a superior tracking performance and robustness through numerical simulation in the presence of parametric uncertainties and unknown disturbances.

  15. Coupling of cavities - the way to impose control over their modes

    DEFF Research Database (Denmark)

    Ivinskaya, Aliaksandra; Lavrinenko, Andrei; Sukhorukov, Andrey A.;

    2010-01-01

    In this work, we demonstrate that the compound mode properties of coupled photonic-crystal cavities can depend critically on the interplay of distance between cavities and their longitudinal shifts. Thus the robust control over the cavity modes can be imposed. The simple coupled-mode theory...... employed for such systems predicts a peculiar behavior of band dispersion in the slow light regime at the photonic band-edge. In particular, it reveals an interesting effect that the frequency detuning of the fundamental supermodes in the coupled cavities can be reduced down to zero. We anticipate...

  16. Electronic control of edge-mode spectrum of integer-hall-effect 2d electron waveguides

    OpenAIRE

    Kouzaev, Guennadi A.

    2015-01-01

    In this paper, the control of the edge-mode spectrum of integer-Hall-effect 2D waveguides by electric field is proposed and modeled with the effective mass approach. Under certain found conditions, the applied transversal electric field allows refining the modal spectrum from non-localized waves, and, additionally, it can switch the edge-mode from the propagating to the evanescent state, and it is interesting in the design of the edge-mode off and on logic components. These waveguides, arbitr...

  17. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    Science.gov (United States)

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-01-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%.

  18. Fuzzy-logic-based hybrid locomotion mode classification for an active pelvis orthosis: Preliminary results.

    Science.gov (United States)

    Yuan, Kebin; Parri, Andrea; Yan, Tingfang; Wang, Long; Munih, Marko; Vitiello, Nicola; Wang, Qining

    2015-08-01

    In this paper, we present a fuzzy-logic-based hybrid locomotion mode classification method for an active pelvis orthosis. Locomotion information measured by the onboard hip joint angle sensors and the pressure insoles is used to classify five locomotion modes, including two static modes (sitting, standing still), and three dynamic modes (level-ground walking, ascending stairs, and descending stairs). The proposed method classifies these two kinds of modes first by monitoring the variation of the relative hip joint angle between the two legs within a specific period. Static states are then classified by the time-based absolute hip joint angle. As for dynamic modes, a fuzzy-logic based method is proposed for the classification. Preliminary experimental results with three able-bodied subjects achieve an off-line classification accuracy higher than 99.49%. PMID:26737144

  19. 75 FR 77569 - Special Conditions: Gulfstream Model GVI Airplane; Electronic Flight Control System Mode...

    Science.gov (United States)

    2010-12-13

    ...; Electronic Flight Control System Mode Annunciation AGENCY: Federal Aviation Administration (FAA), DOT. ACTION... design features include an electronic flight control system. The applicable airworthiness regulations do.... 21.101. Novel or Unusual Design Features The GVI will have a fly-by-wire electronic flight...

  20. Feedback Linearization Control of a Shunt Active Power Filter Using a Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    Tianhua Li

    2013-09-01

    Full Text Available In this paper, a novel feedback linearization based sliding mode controlled parallel active power filter using a fuzzy controller is presented in a three-phase three-wire grid. A feedback linearization control with fuzzy parameter self-tuning is used to implement the DC side voltage regulation while a novel integral sliding mode controller is applied to reduce the total harmonic distortion of the supply current. Since traditional unit synchronous sinusoidal signal calculation methods are not applicable when the supply voltage contains harmonics, a novel unit synchronous sinusoidal signal computing method based on synchronous frame transforming theory is presented to overcome this disadvantage. The simulation results verify that the DC side voltage is very stable for the given value and responds quickly to the external disturbance. A comparison is also made to show the advantages of the novel unit sinusoidal signal calculating method and the super harmonic treatment property of the designed active power filter.

  1. Sliding mode control applied in trajectory-tracking of WMRs and autonomous vehicles

    OpenAIRE

    Solea, Razvan Constantin

    2009-01-01

    The thesis is structured as follows: • Chapter 2: Trajectory tracking problems are summarized. • Chapter 3: Kinematic and dynamic modeling of theWMRs and car-like robots are presented. • Chapter 4: The concept of sliding mode are first introduced. Then the fundamentals of SMC are summarized, including basic definitions, methods of sliding surface and control law design, robustness properties and the methods on handling chattering problems. New sliding-mode trajectory-tracking and sli...

  2. High-order sliding modes and intelligent PID controllers: First steps toward a practical comparison

    OpenAIRE

    Riachy, Samer; Fliess, Michel; Join, Cédric

    2011-01-01

    International audience; This communication is devoted to a "practical" comparison between high-order sliding modes and the recently introduced model-free control. The perfect knowledge of the relative degree of the output variable, which is a standard assumption for sliding modes, is assumed here. Our comparisons are based on two concrete case-studies and on numerous computer simulations. The smoothness of the input variables, the robustness with respect to noises and the straightforward exte...

  3. Path Following of an Underactuated AUV Based on Fuzzy Backstepping Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Xiao Liang

    2016-06-01

    Full Text Available This paper addresses the path following problem of an underactuated autonomous underwater vehicle (AUV with the aim of dealing with parameter uncertainties and current disturbances. An adaptive robust control system was proposed by employing fuzzy logic, backstepping and sliding mode control theory. Fuzzy logic theory is adopted to approximate unknown system function, and the controller was designed by combining sliding mode control with backstepping thought. Firstly, the longitudinal speed was controlled, then the yaw angle was made as input of path following error to design the calm function and the change rate of path parameters. The controller stability was proved by Lyapunov stable theory. Simulation and outfield tests were conducted and the results showed that the controller is of excellent adaptability and robustness in the presence of parameter uncertainties and external disturbances. It is also shown to be able to avoid the chattering of AUV actuators.

  4. Structural control by the use of piezoelectric active members

    Science.gov (United States)

    Fanson, J. L.; Chen, J.-C.

    1987-01-01

    Large Space Structures (LSS) exhibit characteristics which make the LSS control problem different form other control problems. LSS will most likely exhibit low frequency, densely spaced and lightly damped modes. In theory, the number of these modes is infinite. Because these structures are flexible, Vibration Suppression (VS) is an important aspect of LSS operation. In terms of VS, the control actuators should be as low mass as possible, have infinite bandwidth, and be electrically powered. It is proposed that actuators be built into the structure as dual purpose structural elements. A piezoelectric active member is proposed for the control of LSS. Such a device would consist of a piezoelectric actuator and sensor for measuring strain, and screwjack actuator in series for use in quasi-static shape control. An experiment simulates an active member using piezoelectric ceramic thin sheet material on a thin, uniform cantilever beam. The feasibility of using the piezoelectric materials for VS on LSS was demonstrated. Positive positive feedback as a VS control strategy was implemented. Multi-mode VS was achieved with dramatic reduction in dynamic response.

  5. [Adaptation of acrylic resin dentures polymerized using various activation modes].

    Science.gov (United States)

    Takamata, T; Inoue, Y; Hashimoto, K; Sugitou, S; Arakawa, H; Kurasawa, I

    1989-12-01

    The purpose of this in vitro study was to compare the dimensional accuracy of maxillary dentures made using a conventional heat-activated PMMA resin, a pour resin, a visible light-activated resin, and a microwave-activated acrylic resin. Two simple methods for measuring dimensional accuracy were used: (1) weight of impression material entrapped between the base and master die and (2) measurement of the posterior border gap at five locations. The volume of space between the denture base and the master die was determined by (1) computation and (2) estimation. Statistical analysis (Bartlett, ANOVA and Tukey's Tests) supported the following conclusions: (1) all groups showed a processing contraction, most apparent from buccal flange to buccal flange, (2) the poorest fitting group was processed in a brass flask and a water bath at a temperature which rose from 70 to 100 degrees C, using a heat activated resin (Acron), (3) the visible light activated resin (Triad) produced dentures of intermediate accuracy, as did Acupac 20 when either heat or microwave activated, (4) the two best fitting groups were prepared from a chemically activated resin system using pressure at low heat (PER form), and the resin developed for microwave activation (Acron MC).

  6. Displacement and Force Control of a Quarter Car Using a Mixed Mode MR Mount

    Directory of Open Access Journals (Sweden)

    Shuo Wang

    2013-01-01

    Full Text Available In hydraulic hybrid vehicles (HHV, vibration in dual-mode pump/motor units should be isolated from the chassis. A mixed mode magnetorheological (MR fluid mount was adopted to isolate this vibration and was evaluated in a quarter car model. The MR fluid mount was designed to be able to operate in flow mode and squeeze mode independently and simultaneously. For HHVs, it is desirable to control force and displacement transmissibility. These simulation results presented a basis for designing an effective algorithm to control both the displacement transmissibility and force transmissibility. Moreover, a hierarchical controller for minimizing the two requirements for transmissibility was also constructed. At last, a fuzzy logic controller was devised to closely reproduce the effect of the hierarchical controller. The experiments were set up to facilitate the hardware-in-the-loop evaluation of the mount. Results from the experiments showed that the mixed mode MR fluid mount was able to achieve desired dynamic stiffness profile to minimize the dual-transmissibility criterion.

  7. Recent results on structural control of an active precision structure

    Science.gov (United States)

    Chu, C. C.; Fanson, J. L.; Smith, R. S.

    1991-01-01

    This paper describes recent results in structural control of an active precision truss structure at JPL. The goal is to develop practical control methodology and to apply to active truss structures intended for high precision space-based optics applications. The active structure considered incorporates piezoelectric active members which apply control forces internal to the structure and thereby improve the structure's dimensional stability. Two approaches to structural control system design were investigated. The first approach uses only noncollocated measurements of acceleration at the location of a simulated optical component to achieve structural stabilization. The second approach is essentially the same as the first one except that a viscous damper was used in place of a truss member on the structure to improve the dampings of selected flexible modes. The corresponding experimental closed-loop results are presented in this paper.

  8. Rotation in a reversed field pinch with active feedback stabilization of resistive wall modes

    Science.gov (United States)

    Cecconello, M.; Menmuir, S.; Brunsell, P. R.; Kuldkepp, M.

    2006-09-01

    Active feedback stabilization of multiple resistive wall modes (RWMs) has been successfully proven in the EXTRAP T2R reversed field pinch. One of the features of plasma discharges operated with active feedback stabilization, in addition to the prolongation of the plasma discharge, is the sustainment of the plasma rotation. Sustained rotation is observed both for the internally resonant tearing modes (TMs) and the intrinsic impurity oxygen ions. Good quantitative agreement between the toroidal rotation velocities of both is found: the toroidal rotation is characterized by an acceleration phase followed, after one wall time, by a deceleration phase that is slower than in standard discharges. The TMs and the impurity ions rotate in the same poloidal direction with also similar velocities. Poloidal and toroidal velocities have comparable amplitudes and a simple model of their radial profile reproduces the main features of the helical angular phase velocity. RWMs feedback does not qualitatively change the TMs behaviour and typical phenomena such as the dynamo and the 'slinky' are still observed. The improved sustainment of the plasma and TMs rotation occurs also when feedback only acts on internally non-resonant RWMs. This may be due to an indirect positive effect, through non-linear coupling between TMs and RWMs, of feedback on the TMs or to a reduced plasma-wall interaction affecting the plasma flow rotation. Electromagnetic torque calculations show that with active feedback stabilization the TMs amplitude remains well below the locking threshold condition for a thick shell. Finally, it is suggested that active feedback stabilization of RWMs and current profile control techniques can be employed simultaneously thus improving both the plasma duration and its confinement properties.

  9. X-mode reflectometry for MHD activity associated with q=1 surface measurements on Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Vermare, L.; Clairet, F.; Gabillet, F.; Sabot, R.; Sirinelli, A. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Heuraux, S. [Nancy-1 Univ. Henri Poincare, LPMI, CNRS 7040, 54 (France); Leclert, G. [Universite de Provence, LPIIM, UMR 6633 CNRS, 13 - Marseille (France)

    2004-07-01

    Tore Supra is equipped with two fast sweep 20 {mu}s X-mode (FM-CW) reflectometers operating between 50-110 GHz dedicated to density profile determination and a X-mode fixed frequency reflectometer operating between 105-155 GHz for density fluctuations measurements. By operating the profile reflectometer in burst mode (5 {mu}s dead time between two consecutive sweeps) we provide information on plasma fluctuations, such as MHD (magnetohydrodynamics) activity, up to 20 kHz as well as a radial localization of the modes. The temporal evolution of the q = 1 rational surface during sawtooth crash activity has been recorded in the plasma center with high spatial resolution. The observation of the associated MHD mode has been done with both reflectometers and the toroidal plasma rotation velocity has been determined from the phase shift between them. (authors)

  10. Designing Flexible Neuro-Fuzzy System Based on Sliding Mode Controller for Magnetic Levitation Systems

    Directory of Open Access Journals (Sweden)

    Zahra Mohammadi

    2011-07-01

    Full Text Available This study presents a novel controller of magnetic levitation system by using new neuro-fuzzy structures which called flexible neuro-fuzzy systems. In this type of controller we use sliding mode control with neuro-fuzzy to eliminate the Jacobian of plant. At first, we control magnetic levitation system with Mamdanitype neuro-fuzzy systems and logical-type neuro-fuzzy systems separately and then we use two types of flexible neuro-fuzzy systems as controllers. Basic flexible OR-type neuro-fuzzy inference system and basic compromise AND-type neuro-fuzzy inference system are two new flexible neuro-fuzzy controllers which structure of fuzzy inference system (Mamdani or logical is determined in the learning process. We can investigate with these two types of controllers which of the Mamdani or logical type systems has better performance for control of this plant. Finally we compare performance of these controllers with sliding mode controller and RBF sliding mode controller.

  11. Active control design of modular tensegrity structures

    OpenAIRE

    Amouri, Sarah; Averseng, Julien; Dubé, Jean-François

    2013-01-01

    In this paper, a general methodology for the design of modular active tensegrity structures is presented. The objectives are to propose systems such as grids or footbridges that would be able to actively damper their first vibration modes and to adapt their geometry using a small number of activators. This approach is validated experimentally on a plane regular tensegrity grid. Using numerical simulation, an application on the model of a modular tensegrity footbridge is presented.

  12. The Hubble Space Telescope fine guidance system operating in the coarse track pointing control mode

    Science.gov (United States)

    Whittlesey, Richard

    1993-01-01

    The Hubble Space Telescope (HST) Fine Guidance System has set new standards in pointing control capability for earth orbiting spacecraft. Two precision pointing control modes are implemented in the Fine Guidance System; one being a Coarse Track Mode which employs a pseudo-quadrature detector approach and the second being a Fine Mode which uses a two axis interferometer implementation. The Coarse Track Mode was designed to maintain FGS pointing error to within 20 milli-arc seconds (rms) when guiding on a 14.5 Mv star. The Fine Mode was designed to maintain FGS pointing error to less than 3 milli-arc seconds (rms). This paper addresses the HST FGS operating in the Coarse Track Mode. An overview of the implementation, the operation, and both the predicted and observed on orbit performance is presented. The discussion includes a review of the Fine Guidance System hardware which uses two beam steering Star Selector servos, four photon counting photomultiplier tube detectors, as well as a 24 bit microprocessor, which executes the control system firmware. Unanticipated spacecraft operational characteristics are discussed as they impact pointing performance. These include the influence of spherically aberrated star images as well as the mechanical shocks induced in the spacecraft during and following orbital day/night terminator crossings. Computer modeling of the Coarse Track Mode verifies the observed on orbit performance trends in the presence of these optical and mechanical disturbances. It is concluded that the coarse track pointing control function is performing as designed and is providing a robust pointing control capability for the Hubble Space Telescope.

  13. Default Mode Network Activity Predicts Early Memory Decline in Healthy Young Adults Aged 18-31.

    Science.gov (United States)

    Nelson, Steven M; Savalia, Neil K; Fishell, Andrew K; Gilmore, Adrian W; Zou, Fan; Balota, David A; McDermott, Kathleen B

    2016-08-01

    Functional magnetic resonance imaging (fMRI) research conducted in healthy young adults is typically done with the assumption that this sample is largely homogeneous. However, studies from cognitive psychology suggest that long-term memory and attentional control begin to diminish in the third decade of life. Here, 100 participants between the ages of 18 and 31 learned Lithuanian translations of English words in an individual differences study using fMRI. Long-term memory ability was operationalized for each participant by deriving a memory score from 3 convergent measures. Age of participant predicted memory score in this cohort. In addition, degree of deactivation during initial encoding in a set of regions occurring largely in the default mode network (DMN) predicted both age and memory score. The current study demonstrates that early memory decline may partially be accounted for by failure to modulate activity in the DMN.

  14. Default Mode Network Activity Predicts Early Memory Decline in Healthy Young Adults Aged 18-31.

    Science.gov (United States)

    Nelson, Steven M; Savalia, Neil K; Fishell, Andrew K; Gilmore, Adrian W; Zou, Fan; Balota, David A; McDermott, Kathleen B

    2016-08-01

    Functional magnetic resonance imaging (fMRI) research conducted in healthy young adults is typically done with the assumption that this sample is largely homogeneous. However, studies from cognitive psychology suggest that long-term memory and attentional control begin to diminish in the third decade of life. Here, 100 participants between the ages of 18 and 31 learned Lithuanian translations of English words in an individual differences study using fMRI. Long-term memory ability was operationalized for each participant by deriving a memory score from 3 convergent measures. Age of participant predicted memory score in this cohort. In addition, degree of deactivation during initial encoding in a set of regions occurring largely in the default mode network (DMN) predicted both age and memory score. The current study demonstrates that early memory decline may partially be accounted for by failure to modulate activity in the DMN. PMID:26209847

  15. Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-08-01

    Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

  16. The grid-connected PV inverter control basing the exponential sliding mode

    Energy Technology Data Exchange (ETDEWEB)

    Huo, Qunhai; Kong, Li; Pei, Wei; Huang, Shengli; Zhou, Jing [Institute of Electrical Engineering, CAS, Beijing (China)

    2008-07-01

    In order to improve the dynamic performance of the grid-connected PV inverter control system, reduce the hardware and software cost of inverter control design, in view of grid-connected inverter non-linear mathematical model, this paper proposes the design of single-phase current closed loop grid-connected PV inverter control system using the Exponential Sliding Mode Control of the modern control theory. Theory testify of the Exponential Sliding Mode Approach Law applied in the grid-connected inverter is completed, and system stability was proven using Lyapunov theorem. In view of the question of chosen Sliding Mode Approach Law existence the non-linearity possibly to cause system buffeting, used the unit to control continuous method, it can enable smooth after the control having high gain characteristic nearby the cut surface, and it has the resistance disturbance and parameter perturbation ability. Compared with the conventional control system, the result had proven proposed the control strategy accurate, and the system has a good control precision and followed characteristic. (orig.)

  17. Design Robust Fuzzy Sliding Mode Control Technique for Robot Manipulator Systems with Modeling Uncertainties

    Directory of Open Access Journals (Sweden)

    Farzin Piltan

    2013-07-01

    Full Text Available This paper describes the design and implementation of robust nonlinear sliding mode control strategies for robot manipulators whose dynamic or kinematic models are uncertain. Therefore a fuzzy sliding mode tracking controller for robot manipulators with uncertainty in the kinematic and dynamic models is design and analyzes. The controller is developed based on the unit quaternion representation so that singularities associated with the otherwise commonly used three parameter representations are avoided. Simulation results for a planar application of the continuum or hyper-redundant robot manipulator (CRM are provided to illustrate the performance of the developed adaptive controller. These manipulators do not have rigid joints, hence, they are difficult to model and this leads to significant challenges in developing high-performance control algorithms. In this research, a joint level controller for continuum robots is described which utilizes a fuzzy methodology component to compensate for dynamic uncertainties.

  18. Magneto-optic Crystal Polarization Controller Assisted Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    ZHAO Guang-Zhen; GUI Li-Li; XIAO Xiao-Sheng; YANG Chang-Xi

    2011-01-01

    We report a passively mode-locked erbium-doped fiber laser based on a compact magneto-optic crystal polarization controller. The length of the polarization controller consisting of four magneto-optic crystal rotators and two quarter wave-plates is only 10cm.Adjusting the polarization controller, central wavelength around 1559nm and repetition rate 21.10 MHz mode-locked pulse are obtained. Pulse duration and 3 dB spectrum width are 598.4fs and 6.24nm respectively. Single pulse energy is about 151.7pJ. Because of its small size, low insertion loss,good controllability and negligible dispersion, the magneto-optic crystal polarization controller could be an ideal polarization controller in fiber lasers.

  19. Adaptive uniform finite-/fixed-time convergent second-order sliding-mode control

    Science.gov (United States)

    Basin, Michael; Bharath Panathula, Chandrasekhara; Shtessel, Yuri

    2016-09-01

    This paper presents an adaptive gain algorithm for second-order sliding-mode control (2-SMC), specifically a super-twisting (STW)-like controller, with uniform finite/fixed convergence time, that is robust to perturbations with unknown bounds. It is shown that a second-order sliding mode is established as exact finite-time convergence to the origin if the adaptive gain does not have the ability to get reduced and converge to a small vicinity of the origin if the adaptation algorithm does not overestimate the control gain. The estimate of fixed convergence time of the studied adaptive STW-like controller is derived based on the Lyapunov analysis. The efficacy of the proposed adaptive algorithm is illustrated in a tutorial example, where the adaptive STW-like controller with uniform finite/fixed convergence time is compared to the adaptive STW controller with non-uniform finite convergence time.

  20. Modeling and Simulation of Resistive Wall Mode Control In DIII-D

    Science.gov (United States)

    Walker, M. L.; Humphreys, D. A.; Jensen, T. H.; Leuer, J. A.; Nerem, A.; Strait, E. J.; Garofalo, A. M.

    2001-10-01

    Detailed dynamic response models have been developed for all relevant subsystems comprising the DIII-D resistive wall mode (RWM) closed loop control system. These include the switching power amplifiers (SPA), digital plasma control system (PCS), acquisition and control circuitry, and a fully toroidal model of plasma/vessel dynamics based on specification of the marginal wall position from stability codes such as GATO and DCON. These models have been validated with experimental data, including open-loop excitation of the SPA, PCS, and vacuum vessel dynamic responses, and measurement of the growth rate and mode structure of the unstable plasma. These models are incorporated into a closed-loop control simulation to investigate the control limitations which are due to realistic power supply responses. Consequences of and approaches to the intrinsically multivariable RWM control problem are also investigated.

  1. Adaptive Terminal Sliding Mode NDO-Based Control of Underactuated AUV in Vertical Plane

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-01-01

    Full Text Available The depth tracking issue of underactuated autonomous underwater vehicle (AUV in vertical plane is addressed in this paper. Considering the complicated dynamics and kinematics model for underactuated AUV, a more simplified model is obtained based on assumptions. Then a nonlinear disturbance observer (NDO is presented to estimate the external disturbance acting on AUV, and an adaptive terminal sliding mode control (ATSMC based on NDO is applied to enhance the depth tracking performance of underactuated AUV considering both internal and external disturbance. Compared with the traditional sliding mode controller, the static error and chattering problem of the depth tracking process have been clearly improved by adopting NDO-based ATSMC. The stability of control system is proven to be guaranteed according to Lyapunov theory. In the end, simulation results imply that the proposed controller owns strong robustness and satisfied control effectiveness in comparison with the traditional controller.

  2. Development of a Novel Fractional Order Sliding Mode Controller for a Gun

    Directory of Open Access Journals (Sweden)

    Qiang Gao

    2013-09-01

    Full Text Available To solve the nonlinearity phenomenon of a Gun Control System (GCS, a novel Fractional order Sliding Mode Control (FoSMC strategy is proposed in this study. By inducing the fractional order calculus, a Fractional Order PID (FOPID type sliding surface is especially designed and consequently an equivalent control discipline with fractional order dynamics is induced. The saturation function is employed as the switch function. By numerical simulation, the dynamic characteristics of the FoSMC based control system are analyzed and compared with Conventional Sliding Mode Control (CSMC system. The results demonstrate that the FoSMC system could reach up to the equilibrium state more smoothly, which shall significantly suppress the inherent chatter effects. Besides, the FoSMC based gun control system is of high response rate, better positioning accuracy and high robustness, which is suitable for fast, smooth and accurate adjustments of the gun.

  3. A high repetition rate passively Q-switched microchip laser for controllable transverse laser modes

    Science.gov (United States)

    Dong, Jun; Bai, Sheng-Chuang; Liu, Sheng-Hui; Ueda, Ken-Ichi; Kaminskii, Alexander A.

    2016-05-01

    A Cr4+:YAG passively Q-switched Nd:YVO4 microchip laser for versatile controllable transverse laser modes has been demonstrated by adjusting the position of the Nd:YVO4 crystal along the tilted pump beam direction. The pump beam diameter-dependent asymmetric saturated inversion population inside the Nd:YVO4 crystal governs the oscillation of various Laguerre-Gaussian, Ince-Gaussian and Hermite-Gaussian modes. Controllable transverse laser modes with repetition rates over 25 kHz and up to 183 kHz, depending on the position of the Nd:YVO4 crystal, have been achieved. The controllable transverse laser beams with a nanosecond pulse width and peak power over hundreds of watts have been obtained for potential applications in optical trapping and quantum computation.

  4. On Optimal Control of Non-Autonomous Switched Systems with a Fixed Mode Sequence

    Science.gov (United States)

    Kamgarpour, Maryam; Tomlin, Claire

    2012-01-01

    We consider differentiability with respect to the switch times of the value function of an optimal control problem for a non-autonomous switched system. The control variables are the switch times between the modes and the input in each mode. We provide a method to compute the derivative of the cost function given a nominal input. Then, we view the optimal control problem as a parametrized optimization problem in which the switch times are the parameters and the optimization is over the set of feasible inputs of each mode. From this point of view, we provide conditions under which the continuity and differentiability of the optimal value function, that is the cost function optimized over the inputs, can be guaranteed.

  5. Operation Modes and Control Schemes for a Telerobot with Time Delay

    Directory of Open Access Journals (Sweden)

    Pengwen Xiong

    2012-08-01

    Full Text Available Telerobot system plays an important role in executing task under hazard environment. As the computer networks such as the Internet are being used as the communication channel of telerobot systems, varying time delay causes the overall system unstable and reduces the performance of transparency. In this paper, we propose twelve operation modes with different control schemes for telerobot on the Internet with time delay. And an optimal operation mode with control scheme is specified for telerobot with time delay, based on the tradeoff between passivity and transparency properties. We experimentally confirm the validity of the proposed optimal mode and control scheme by using a simple one DOF master–slave manipulator system.

  6. Phased annular array transducers for omnidirectional guided wave mode control in isotropic plate like structures

    International Nuclear Information System (INIS)

    Ultrasonic guided waves are fast emerging as a reliable tool for continuous structural health monitoring. Their multi-modal nature along with their long range propagation characteristics offer several possibilities for interrogating structures. Transducers commonly used to generate guided waves in structures excite multiple modes at any frequency; their complex scattering and reflection from defects and boundaries often complicates the extraction of useful information. Often it is desirable to control the guided wave modes propagating in a structure to take advantage of their unique properties for different applications. Earlier attempts at guided wave mode control involved developing fixed wavelength linear and annular array transducers. Their only disadvantage is that the transducer is limited to a particular wavelength and a change in wavelength necessitates a change in the transducer. In this paper, we propose the development of an annular array transducer that can generate mode controlled omnidirectional guided waves by independently controlling the amplitude and phase of the array elements. A simplified actuator model that approximates the transducer loading on the structure to a constant pressure load under the array elements is assumed and an optimization problem is set up to compute the excitation voltage and phase of the elements. A five element annular array transducer is designed utilizing 1–3 type piezocomposite materials. The theoretical computations are experimentally verified on an aluminum plate like structure by exciting A0 and S0 guided wave modes. (paper)

  7. Power system damping - Structural aspects of controlling active power

    Energy Technology Data Exchange (ETDEWEB)

    Samuelsson, O.

    1997-04-01

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

  8. Microcontroller-based peak current mode control using digital slope compensation

    OpenAIRE

    Hallworth, Michael; Shirsavar, Ali

    2012-01-01

    Microcontroller-based peak current mode control of a buck converter is investigated. The new solution uses a discrete time controller with digital slope compensation. This is implemented using only a single-chip microcontroller to achieve desirable cycle-by-cycle peak current limiting. The digital controller is implemented as a two-pole, two-zero linear difference equation designed using a continuous time model of the buck converter and a discrete time transform. Subharmonic oscillations are ...

  9. Chattering-Free Adaptive Sliding Mode Control for Attitude Tracking of Spacecraft with External Disturbance

    Directory of Open Access Journals (Sweden)

    Xuxi Zhang

    2014-01-01

    Full Text Available The attitude tracking problem of spacecraft in the presence of unknown disturbance is investigated. By using the adaptive control technique and the Lyapunov stability theory, a chattering-free adaptive sliding mode control law is proposed for the attitude tracking problem of spacecraft with unknown disturbance. Simulation results are employed to demonstrate the effectiveness of the proposed control design technique in this paper.

  10. Development of a Novel Fractional Order Sliding Mode Controller for a Gun

    OpenAIRE

    Qiang Gao; Haijun Chen; Guolai Yang; Jilin Chen; Yuanlong Hou

    2013-01-01

    To solve the nonlinearity phenomenon of a Gun Control System (GCS), a novel Fractional order Sliding Mode Control (FoSMC) strategy is proposed in this study. By inducing the fractional order calculus, a Fractional Order PID (FOPID) type sliding surface is especially designed and consequently an equivalent control discipline with fractional order dynamics is induced. The saturation function is employed as the switch function. By numerical simulation, the dynamic characteristics of the FoSMC ba...

  11. Decoupled Sliding Mode Control for a Novel 3-DOF Parallel Manipulator with Actuation Redundancy

    Directory of Open Access Journals (Sweden)

    Niu Xuemei

    2015-05-01

    Full Text Available This paper presents a decoupled nonsingular terminal sliding mode controller (DNTSMC for a novel 3-DOF parallel manipulator with actuation redundancy. According to kinematic analysis, the inverse dynamic model for a novel 3-DOF redundantly actuated parallel manipulator is formulated in the task space using Lagrangian formalism and decoupled into three entirely independent subsystems under generalized coordinates to significantly reduce system complexity. Based on the dynamic model, a decoupled sliding mode control strategy is proposed for the parallel manipulator; the idea behind this strategy is to design a nonsingular terminal sliding mode controller for each subsystem, which can drive states of three subsystems to the original equilibrium points simultaneously by two intermediate variables. Additionally, a RBF neural network is used to compensate the cross-coupling force and gravity to enhance the control precision. Simulation and experimental results show that the proposed DNTSMC can achieve better control performances compared with the conventional sliding mode controller (SMC and the DNTSMC without compensator.

  12. The Study of Operation Modes and Control Strategies of a Multidirectional MC for Battery Based System

    Directory of Open Access Journals (Sweden)

    Saman Toosi

    2015-01-01

    Full Text Available To enhance the performance of stand-alone battery based system and to achieve the continuous power transmission, the behavior of multidirectional matrix converter (MDMC has been analyzed in different operation modes. A systematic method interfacing a renewable source, a storage battery, and a load is proposed for a stand-alone battery based power system (SABBPS to utilize the MDMC as PWM converter, inverter, or PWM converter and inverter in different operation modes. In this study, the Extended Direct Duty Pulse Width Modulation (EDDPWM technique has been applied to control the power flow path between the renewable source, load, and the battery. Corresponding to generator voltage, input frequency, and loads demands, several operating states and control strategies are possible. Therefore, the boundaries and distribution of operation modes are discussed and illustrated to improve the system performance. The mathematical equation of the EDDPWM under different operation modes has been derived to achieve the maximum voltage ratio in each mode. The theoretical and modulation concepts presented have been verified in simulation using MATLAB and experimental testing. Moreover, the THD, ripple, and power flow direction have been analyzed for output current to investigate the behavior of system in each operation mode.

  13. Design of practical sliding-mode controllers with constant switching frequency for power converters

    Energy Technology Data Exchange (ETDEWEB)

    Navarro-Lopez, Eva M. [School of Computer Science, Centre for Interdisciplinary Computational and Dynamical Analysis, The University of Manchester, Oxford Road, Kilburn Building, Manchester M13 9PL (United Kingdom); Cortes, Domingo [Seccion de Mecatronica, Departamento de Ingenieria Electrica, CINVESTAV-IPN, Av. IPN 2508, Col. San Pedro Zacatenco, 07360 Mexico City (Mexico); Castro, Christian [Centro de Investigacion en Computacion del IPN, Av. Jose Othon de Mendizabal s/n, Col. Nueva Industrial Vallejo, 07738 Mexico City (Mexico)

    2009-05-15

    A novel experimentally motivated method in order to design a family of easy-to-implement sliding-mode controllers for power converters is proposed. Two main results are presented. First, the relation between sliding-mode control and average control is reinterpreted so that the limitation of the switching frequency for the closed-loop system is achieved in a more direct way than other methods so far reported in the literature. For this purpose, a class of sliding surfaces which makes the associated equivalent control be the system average control is proposed. Second, the achievement of a constant switching frequency in the controlled system is assured without requiring the sliding-mode-based controller to be modified, unlike most previous works. As a result, the proposed sliding surfaces-type can be directly implemented via a pulse-width modulator. The control methodology is implemented for the voltage control in a boost converter prototype in which the load is considered unknown. Experimental results confirm high performance and robustness under parameters variation. Furthermore, the solution proposed is easy to implement and well-suited for other power converters. (author)

  14. IMPLEMENTATION OF MULTILEVEL INVERTER USING MPPT BASED SLIDING MODE CONTROL FOR PV CELL

    Directory of Open Access Journals (Sweden)

    M.R.Vishnupriya

    2013-06-01

    Full Text Available In this project photovoltaic array is used as source. The photovoltaic energy is used to feed the inverter through the step up converter. The output for solar module is connected to the battery. So the supply is given continuously by the battery to the system. The output of the solar may vary due to the radiation and will affect the battery. So the lifetime of battery is reduced. It is necessary to protect the battery from the non-linear solar energy, charge controller is used. In order to track maximum power, sliding mode controller is used. In the step up converter a new method is used. The new step-up converter consists of coupled inductor and fixed capacitor. The voltage stress of active switch is being reduced byclamp capacitor. The output of the new topology of dc-dc converter is given to hybrid multilevel inverter which consists of reduced number of switches. The overall system is simulated using MATLAB prototypeof the proposed system is developed and output is verified with simulation results.

  15. Digital control of high-frequency switched-mode power converters

    CERN Document Server

    Corradini, Luca; Mattavelli, Paolo; Zane, Regan

    This book is focused on the fundamental aspects of analysis, modeling and design of digital control loops around high-frequency switched-mode power converters in a systematic and rigorous manner Comprehensive treatment of digital control theory for power converters Verilog and VHDL sample codes are provided Enables readers to successfully analyze, model, design, and implement voltage, current, or multi-loop digital feedback loops around switched-mode power converters Practical examples are used throughout the book to illustrate applications of the techniques developed Matlab examples are also

  16. Running Control Mode for In-Duct FGD with No-Bypass Design

    Institute of Scientific and Technical Information of China (English)

    Li

    2010-01-01

    The desulfuration system in the second phase project of Sanhe Power Plant is the first such system that adopts in-duct FGD with no-bypass design by domestic power plants. Different from that of the conventional FGD with bypass design, a running control mode, which is important for the security of the absorbing tower within the designed ranges, shall be made to ensure the flue gas temperature and dust concentration at the inlet of the absorbing tower. The stable running of the system shows that the control mode is feasible.

  17. High-order sliding mode control of a DC motor drive via a switched controlled multi-cellular converter

    Science.gov (United States)

    Djemaï, M.; Busawon, K.; Benmansour, K.; Marouf, A.

    2011-11-01

    In this article, we present a high-order sliding mode controller of a DC motor drive connected to a multi-cellular converter. More specifically, we design a second-order (super-twisting) control algorithm for the speed regulation of a DC motor. For this, a switching control for the multi-cellular converter is derived in order to supply the correct reference value for the speed regulation. A practical implementation of the controller is realised using a laboratory set-up. The performance and the validity of the controller are shown experimentally.

  18. Design of Nonlinear Robust Rotor Current Controller for DFIG Based on Terminal Sliding Mode Control and Extended State Observer

    Directory of Open Access Journals (Sweden)

    Guowei Cai

    2014-01-01

    Full Text Available As to strong nonlinearity of doubly fed induction generators (DFIG and uncertainty of its model, a novel rotor current controller with nonlinearity and robustness is proposed to enhance fault ride-though (FRT capacities of grid-connected DFIG. Firstly, the model error, external disturbances, and the uncertain factors were estimated by constructing extended state observer (ESO so as to achieve linearization model, which is compensated dynamically from nonlinear model. And then rotor current controller of DFIG is designed by using terminal sliding mode variable structure control theory (TSMC. The controller has superior dynamic performance and strong robustness. The simulation results show that the proposed control approach is effective.

  19. Discrete-time sliding mode control for MR vehicle suspension system

    International Nuclear Information System (INIS)

    This paper presents control performance of a full-vehicle suspension system featuring magnetorheological (MR) dampers via a discrete-time sliding mode control algorithm (DSMC). A cylindrical MR damper is designed by incorporating Bingham model of the MR fluid and the field-dependent damping characteristics of the MR damper are evaluated. A full-vehicle suspension model installed with independent four MR dampers is constructed and the governing equations which include vertical, pitch and roll motion are derived. A discrete-time control model is established with considering system uncertainties and a discrete-time sliding mode controller which has inherent robustness to model uncertainty and external disturbance is formulated. Vibration control performances under bump excitation are evaluated and presented.

  20. Adaptive Fuzzy Sliding Mode Tracking Control of Uncertain Underactuated Nonlinear Systems: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Faten Baklouti

    2016-01-01

    Full Text Available The trajectory tracking of underactuated nonlinear system with two degrees of freedom is tackled by an adaptive fuzzy hierarchical sliding mode controller. The proposed control law solves the problem of coupling using a hierarchical structure of the sliding surfaces and chattering by adopting different reaching laws. The unknown system functions are approximated by fuzzy logic systems and free parameters can be updated online by adaptive laws based on Lyapunov theory. Two comparative studies are made in this paper. The first comparison is between three different expressions of reaching laws to compare their abilities to reduce the chattering phenomenon. The second comparison is made between the proposed adaptive fuzzy hierarchical sliding mode controller and two other control laws which keep the coupling in the underactuated system. The tracking performances of each control law are evaluated. Simulation examples including different amplitudes of external disturbances are made.

  1. Mode tuning of a simplified string instrument using time-dimensionless state-derivative control

    Science.gov (United States)

    Benacchio, Simon; Chomette, Baptiste; Mamou-Mani, Adrien; Finel, Victor

    2015-01-01

    In recent years, there has been a growing interest in smart structures, particularly in the field of musical acoustics. Control methods, initially developed to reduce vibration and damage, can be a good way to shift modal parameters of a structure in order to modify its dynamic response. This study focuses on smart musical instruments and aims to modify their radiated sound. This is achieved by controlling the modal parameters of the soundboard of a simplified string instrument. A method combining a pole placement algorithm and a time-dimensionless state-derivative control is used and quickly compared to a usual state control method. Then the effect of the mode tuning on the coupling between the string and the soundboard is experimentally studied. Controlling two vibration modes of the soundboard, its acoustic response and the damping of the third partial of the sound are modified. Finally these effects are listened in the radiated sound.

  2. Sliding Mode Predictive Control of Main Steam Pressure in Coal-fired Power Plant Boiler

    Institute of Scientific and Technical Information of China (English)

    史元浩; 王景成; 章云锋

    2012-01-01

    Since the combustion system of coal-fired boiler in thermal power plant is characterized as time varying, strongly coupled, and nonlinear, it is hard to achieve a satisfactory performance by the conventional proportional integral derivative (PID) control scheme. For the characteristics of the main steam pressure in coal-fired power plant boiler, the sliding mode control system with Smith predictive structure is proposed to look for performance and robustness improvement. First, internal model control (IMC) and Smith predictor (SP) is used to deal with the time delay, and sliding mode controller (SMCr) is designed to overcome the model mismatch. Simulation results show the effectiveness of the proposed controller compared with conventional ones.

  3. Platelet Serotonin Transporter Function Predicts Default-Mode Network Activity

    OpenAIRE

    Christian Scharinger; Ulrich Rabl; Christian H. Kasess; Meyer, Bernhard M.; Tina Hofmaier; Kersten Diers; Lucie Bartova; Gerald Pail; Wolfgang Huf; Zeljko Uzelac; Beate Hartinger; Klaudius Kalcher; Thomas Perkmann; Helmuth Haslacher; Andreas Meyer-Lindenberg

    2014-01-01

    Background The serotonin transporter (5-HTT) is abundantly expressed in humans by the serotonin transporter gene SLC6A4 and removes serotonin (5-HT) from extracellular space. A blood-brain relationship between platelet and synaptosomal 5-HT reuptake has been suggested, but it is unknown today, if platelet 5-HT uptake can predict neural activation of human brain networks that are known to be under serotonergic influence. Methods A functional magnetic resonance study was performed in 48 healthy...

  4. Research on Adaptive Dual-Mode Switch Control Strategy for Vehicle Maglev Flywheel Battery

    Directory of Open Access Journals (Sweden)

    Hui Gao

    2015-01-01

    Full Text Available Because of the jamming signal is real-time changeable and control algorithm cannot timely tracking control flywheel rotor, this paper takes vehicle maglev flywheel battery as the research object. One kind of dual-model control strategy is developed based on the analysis of the vibration response impact of the flywheel battery control system. In view of the complex foundation vibration problems of electric vehicles, the nonlinear dynamic simulation model of vehicle maglev flywheel battery is solved. Through analyzing the nonlinear vibration response characteristics, one kind of dual-mode adaptive hybrid control strategy based on H∞ control and unbalance displacement feed-forward compensation control is presented and a real-time switch controller is designed. The reliable hybrid control is implemented, and the stability in the process of real-time switch is solved. The results of this project can provide important basic theory support for the research of vehicle maglev flywheel battery control system.

  5. Artemisinin inhibits chloroplast electron transport activity: mode of action.

    Directory of Open Access Journals (Sweden)

    Adyasha Bharati

    Full Text Available Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo, behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B; the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth.

  6. A digitally controlled PWM/PSM dual-mode DC/DC converter

    Institute of Scientific and Technical Information of China (English)

    Zhen Shaowei; Zhang Bo; Luo Ping; Hou Sijian; Ye Jingxin; Ma Xiao

    2011-01-01

    A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed.Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM).The converter works in PSM at DCM and in 2 MHz PWM at CCM.Switching loss is reduced at a light load by skipping cycles.Thus high conversion efficiency is realized in a wide load current.The implementations of PWM control blocks,such as the ADC,the digital pulse width modulator (DPWM) and the loop compensator,and PSM control blocks are described in detail.The parameters of the loop compensator can be programmed for different external component values and switching frequencies,which is much more flexible than its analog rivals.The chip is manufactured in 0.13 μm CMOS technology and the chip area is 1.21 mm2.Experimental results show that the conversion efficiency is high,being 90% at 200 mA and 67% at 20 mA.Meanwhile,the measured load step response shows that the proposed dual-mode converter has good stability.

  7. Mine-Hoist Active Fault Tolerant Control System and Strategy

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-jie; WANG Yao-cai; MENG Jiang; ZHAO Peng-cheng; CHANG Yan-wei

    2005-01-01

    Based on fault diagnosis and fault tolerant technologies, the mine-hoist active fault-tolerant control system (MAFCS) is presented with corresponding strategies,, which includes the fault diagnosis module (FDM), the dynamic library (DL) and the fault-tolerant control module (FCM). When a fault is judged from some sensor by FDM, FCM reconfigure the state of MAFCS by calling the parameters from all sub libraries in DL, in order to ensure the reliability and safety of mine hoist. The simulating result shows that, MAFCS is of certain intelligence, which can adopt the corresponding control strategies according to different fault modes, even when there are quite difference between the real data and the prior fault modes.

  8. Active mode locking of quantum cascade lasers operating in external ring cavity

    CERN Document Server

    Revin, D G; Wang, Y; Cockburn, J W; Belyanin, A

    2015-01-01

    Stable ultrashort light pulses and frequency combs generated by mode-locked lasers have many important applications including high-resolution spectroscopy, fast chemical detection and identification, studies of ultrafast processes, and laser metrology. While compact mode-locked lasers emitting in the visible and near infrared range have revolutionized photonic technologies, the systems operating in the mid-infrared range where most gases have their strong absorption lines, are bulky and expensive and rely on nonlinear frequency down-conversion. Quantum cascade lasers are the most powerful and versatile compact light sources in the mid-infrared range, yet achieving their mode locked operation remains a challenge despite dedicated effort. Here we report the first demonstration of active mode locking of an external-cavity quantum cascade laser. The laser operates in the mode-locked regime at room temperature and over the full dynamic range of injection currents of a standard commercial laser chip.

  9. Synchronizing Spatiotemporal Chaos via a Composite Disturbance Observer-Based Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Congyan Chen

    2014-01-01

    Full Text Available The sliding mode control schemes are investigated to synchronize two spatiotemporal chaotic systems, which are two arrays of a large number of coupled chaotic oscillators. Firstly, sliding mode manifolds with the desired performance are designed. The asymptotic convergence to the origin of the synchronization errors is also proved. However, the terms from parameter fluctuations in equivalent controls are usually impossible to be measured directly. So we regard them as lumped disturbances, but, for practical application, it is difficult to obtain the upper bound of lumped disturbances in advance which often results in a conservative sliding mode control law with large control effort, causing a large amount of chattering. To reduce the chattering and improve the performance of the system, a disturbance observer is designed to estimate the lumped disturbances. A composite synchronization controller that consists of a sliding mode feedback part and a feedforward compensation part based on disturbance observer is developed. The numerical simulation results are presented to show the effectiveness of the proposed methods.

  10. Usability Assessment of Two Different Control Modes for the Master Console of a Laparoscopic Surgical Robot

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhang

    2012-01-01

    Full Text Available The objective of this study is to evaluate potential interface control modes for a compact four-degree-of-freedom (4-DOF surgical robot. The goal is to improve robot usability by incorporating a sophisticated haptics-capable interface. Two control modes were developed using a commercially available haptic joystick: (1 a virtually point-constrained interface providing an analog for constrained laparoscopic motion (3-DOF rotation and 1-DOF translation, and (2 an unconstrained Cartesian input interface mapping more directly to the surgical tool tip motions. Subjects (n = 5 successfully performed tissue identification and manipulation tasks in an animal model in point-constrained and unconstrained control modes, respectively, with speed roughly equal to that achieved in similar manual procedures, and without a steep learning curve. The robot control was evaluated through bench-top tests and a subsequent qualitative questionnaire (n = 15. The results suggest that the unconstrained control mode was preferred for both camera guidance and tool manipulations.

  11. Curve Squeal of Train Wheels, Part 3: Active Control

    Science.gov (United States)

    HECKL, MARIA A.; HUANG, X. Y.

    2000-01-01

    This paper presents a new method to annul the squeal noise that is produced by trains traversing a curve. The method is a special form of active control, applied to suppress the bending oscillations of a squealing wheel. It is essentially a feedback system with the following components: sensor, narrowband filter, phase-shifter, amplifier and actuator. The control signal driving the actuator has only a single frequency (set at the filter), and that frequency typically corresponds to one of the bending modes of the wheel. Two versions of the feedback system are considered. In the first version, the actuator exerts a control force on the wheel, and in the second version, the actuator imposes a velocity on the rail. A mathematical model is presented and predictions are made for the performance of both versions. The coupling of the different wheel modes by the control system is discussed. A model rig is described which was used for a practical demonstration of this form of active control. Differences from more conventional forms of active control are pointed out.

  12. Longitudinal changes of amygdala and default mode activation in adolescents prenatally exposed to cocaine.

    Science.gov (United States)

    Li, Zhihao; Coles, Claire D; Lynch, Mary Ellen; Luo, Yuejia; Hu, Xiaoping

    2016-01-01

    Prenatal cocaine exposure (PCE) is associated with long-term and negative effect on arousal regulation. Recent neuroimaging studies have examined brain mechanisms related to arousal dysregulation with cross-sectional experimental designs; but longitudinal changes in the brain, reflecting group differences in neurodevelopment, have never been directly examined. To directly assess the interaction of PCE and neurodevelopment, the present study used a longitudinal design to analyze functional magnetic resonance imaging (fMRI) data collected from 33 adolescents (21 with PCE and 12 non-exposed controls) while they performed the same working memory task with emotional distracters at two points in time. The mean age of participants was 14.3 years at time_1 and 16.7 years at time_2. With confounding factors statistically controlled, the fMRI data revealed significant exposure-by-time interaction in the activations of the amygdala and default mode network (DMN). For the control adolescents, brain activations associated with emotional arousal (amygdala) and cognitive effort (DMN) were both reduced at time_2 as compared to that at time_1. However, these activation reductions were not observed in the PCE group, indicating persistently high levels of emotional arousal and cognitive effort. In addition, correlations between longitudinal changes in the brain and in behavior have shown that adolescents with persistently high emotional arousal were more likely in need of high cognitive effort; and their cognitive performance was more likely to be affected by distractive challenges. The present results complement and extend previous findings from cross-sectional studies with further evidence supporting the view of PCE associated long-term teratogenic effects on arousal regulation.

  13. A Novel Approach to Sliding Mode Control of Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Hongwei Xia

    2013-01-01

    Full Text Available This paper is concerned with the sliding mode control for a class of linear systems with time-varying delays. By utilizing a novel Lyapunov-Krasovskii functional and combining it with the delay fractioning approach as well as the free-weighting matrix technology, a sufficient condition is established such that the resulting sliding mode dynamics is asymptotically stable. Then, a sliding mode controller for reaching motion is synthesized to guarantee that the trajectories of the resulting closed-loop system can be driven onto a prescribed sliding surface and maintained there for all subsequent time. A numerical example is provided to illustrate the effectiveness of the proposed design approach.

  14. Dynamics and stabilization of peak current-mode controlled buck converter with constant current load

    Institute of Scientific and Technical Information of China (English)

    冷敏瑞; 周国华; 张凯暾; 李振华

    2015-01-01

    The discrete iterative map model of peak current-mode controlled buck converter with constant current load (CCL), containing the output voltage feedback and ramp compensation, is established in this paper. Based on this model the com-plex dynamics of this converter is investigated by analyzing bifurcation diagrams and the Lyapunov exponent spectrum. The effects of ramp compensation and output voltage feedback on the stability of the converter are investigated. Experimental results verify the simulation and theoretical analysis. The stability boundary and chaos boundary are obtained under the theoretical conditions of period-doubling bifurcation and border collision. It is found that there are four operation regions in the peak current-mode controlled buck converter with CCL due to period-doubling bifurcation and border-collision bifur-cation. Research results indicate that ramp compensation can extend the stable operation range and transfer the operating mode, and output voltage feedback can eventually eliminate the coexisting fast-slow scale instability.

  15. Active interaction control for civil structures

    OpenAIRE

    Wang, Luo-Jia

    1997-01-01

    This thesis presents a civil engineering approach to active control for civil structures. The proposed control technique, termed Active Interaction Control (AIC), utilizes dynamic interactions between different structures, or components of the same structure, to reduce the resonance response of the controlled or primary structure under earthquake excitations. The primary control objective of AIC is to minimize the maximum story drift of the primary structure. This is accomplished by timing th...

  16. Mode of physical activity and self-efficacy in older adults: a latent growth curve analysis.

    Science.gov (United States)

    McAuley, E; Katula, J; Mihalko, S L; Blissmer, B; Duncan, T E; Pena, M; Dunn, E

    1999-09-01

    A randomized controlled trial examined the effect of two physical activity modes on changes in self-efficacy over the course of a 12-month period in older, formerly sedentary adults (N = 174, M age = 65.5 years). Participants were randomized into either an aerobic activity group or a stretching and toning group. Structural equation modeling was employed to conduct multiple sample latent growth curve analyses of individual growth in exercise and physical self-efficacy over time. Results revealed a curvilinear growth pattern for both types of efficacy with increases occurring over the first 6 months followed by declines at the 6-month follow-up. There was a significant treatment by mean level growth interaction for exercise efficacy with both groups increasing over time, but the aerobic group evidenced a twofold increase in growth over the stretching group. Structural analyses indicated that frequency of exercise participation was a significant predictor of overall growth in efficacy, and improvements in fitness were only related to exercise efficacy growth in the stretching group. Findings are discussed in terms of social cognitive theory and further application of latent growth curve modeling to studies of physical activity effects in older adults. PMID:10542821

  17. Modulation of western North Pacific tropical cyclone activity by the Atlantic Meridional Mode

    Science.gov (United States)

    Zhang, Wei; Vecchi, Gabriel A.; Villarini, Gabriele; Murakami, Hiroyuki; Rosati, Anthony; Yang, Xiaosong; Jia, Liwei; Zeng, Fanrong

    2016-05-01

    This study examines the year-to-year modulation of the western North Pacific (WNP) tropical cyclones (TC) activity by the Atlantic Meridional Mode (AMM) using both observations and the Geophysical Fluid Dynamics Laboratory Forecast-oriented Low Ocean Resolution Version of CM2.5 (FLOR) global coupled model. 1. The positive (negative) AMM phase suppresses (enhances) WNP TC activity in observations. The anomalous occurrence of WNP TCs results mainly from changes in TC genesis in the southeastern part of the WNP. 2. The observed responses of WNP TC activity to the AMM are connected to the anomalous zonal vertical wind shear (ZVWS) caused by AMM-induced changes to the Walker circulation. During the positive AMM phase, the warming in the North Atlantic induces strong descending flow in the tropical eastern and central Pacific, which intensifies the Walker cell in the WNP. The intensified Walker cell is responsible for the suppressed (enhanced) TC genesis in the eastern (western) part of the WNP by strengthening (weakening) ZVWS. 3. The observed WNPTC-AMM linkage is examined by the long-term control and idealized perturbations experiment with FLOR-FA. A suite of sensitivity experiments strongly corroborate the observed WNPTC-AMM linkage and underlying physical mechanisms.

  18. Thickness mode EMIS of constrained proof-mass piezoelectric wafer active sensors

    Science.gov (United States)

    Kamas, Tuncay; Giurgiutiu, Victor; Lin, Bin

    2015-11-01

    This paper addresses theoretical and experimental work on thickness-mode electromechanical (E/M) impedance spectroscopy (EMIS) of proof-mass piezoelectric wafer active sensors (PMPWAS). The proof-mass (PM) concept was used to develop a new method for tuning the ultrasonic wave modes and for relatively high frequency local modal sensing by the PM affixed on PWAS. In order to develop the theoretical basis of the PMPWAS tuning concept, analytical analyses were conducted by applying the resonator theory to derive the EMIS of a PWAS constrained on one and both surfaces by isotropic elastic materials. The normalized thickness-mode shapes were obtained for the normal mode expansion (NME) method to eventually predict the thickness-mode EMIS using the correlation between PMPWAS and the structural dynamic properties of the substrate. Proof-masses of different sizes and materials were used to tune the system resonance towards an optimal frequency point. The results were verified by coupled-field finite element analyses (CF-FEA) and experimental results. An application of the tuning effect of PM on the standing wave modes was discussed as the increase in PM thickness shifts the excitation frequency of the wave mode toward the surface acoustic wave (SAW) mode.

  19. Cooperative Control Method of Active and Semiactive Control: New Framework for Vibration Control

    OpenAIRE

    Kazuhiko Hiramoto

    2014-01-01

    A new control design framework for vibration control, the cooperative control of active and semiactive control, is proposed in the paper. In the cooperative control, a structural system having both of an actuator and a semiactive control device, for example, MR damper and so forth, is defined as the control object. In the proposed control approach, the higher control performance is aimed by the cooperative control between the active control with the actuator and the semiactive control with th...

  20. Resistive Wall Mode feedback on DIII-D using Linear Quadratic Gaussian control and a GPU powered control system

    Science.gov (United States)

    Clement, M. D.; Navratil, G. A.; Hanson, J. M.; Bialek, J.; Piglowski, D. A.; Penaflor, B. G.

    2015-11-01

    A Graphics Processing Unit (GPU) based control system has been installed on the DIII-D tokamak for Resistive Wall Mode (RWM) control similar to one implemented at the HBT-EP tokamak. DIII-D can excite RWMs, which are strong, locked or nearly locked kink modes whose rotation frequencies do not evolve quickly and are slow compared to their growth rates. Simulations have predicted that modern control techniques like Linear Quadratic Gaussian (LQG) control will perform better than classical control techniques when using control coils external to the vacuum vessel. An LQG control algorithm based on the VALEN model for the RWM has been developed and tested on this system. Early tests have shown the algorithm is able to track and suppress with external control coils the plasma response of an n=1 perturbation driven by internal control coils. An overview of the control hardware, VALEN model, control algorithm and initial results will be presented. Supported by the US DOE under DE-FG02-04ER54761 and DE-FC02-04ER54698.

  1. Identification of active elementary flux modes in mitochondria using selectively permeabilized CHO cells.

    Science.gov (United States)

    Nicolae, Averina; Wahrheit, Judith; Nonnenmacher, Yannic; Weyler, Christian; Heinzle, Elmar

    2015-11-01

    Metabolic compartmentation is a key feature of mammalian cells. Mitochondria are the powerhouse of eukaryotic cells, responsible for respiration and the TCA cycle. We accessed the mitochondrial metabolism of the economically important Chinese hamster ovary (CHO) cells using selective permeabilization. We tested key substrates without and with addition of ADP. Based on quantified uptake and production rates, we could determine the contribution of different elementary flux modes to the metabolism of a substrate or substrate combination. ADP stimulated the uptake of most metabolites, directly by serving as substrate for the respiratory chain, thus removing the inhibitory effect of NADH, or as allosteric effector. Addition of ADP favored substrate metabolization to CO2 and did not enhance the production of other metabolites. The controlling effect of ADP was more pronounced when we supplied metabolites to the first part of the TCA cycle: pyruvate, citrate, α-ketoglutarate and glutamine. In the second part of the TCA cycle, the rates were primarily controlled by the concentrations of C4-dicarboxylates. Without ADP addition, the activity of the pyruvate carboxylase-malate dehydrogenase-malic enzyme cycle consumed the ATP produced by oxidative phosphorylation, preventing its accumulation and maintaining metabolic steady state conditions. Aspartate was taken up only in combination with pyruvate, whose uptake also increased, a fact explained by complex regulatory effects. Isocitrate dehydrogenase and α-ketoglutarate dehydrogenase were identified as the key regulators of the TCA cycle, confirming existent knowledge from other cells. We have shown that selectively permeabilized cells combined with elementary mode analysis allow in-depth studying of the mitochondrial metabolism and regulation.

  2. Online Adaptive Error Compensation SVM-Based Sliding Mode Control of an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Kaijia Xue

    2016-01-01

    Full Text Available Unmanned Aerial Vehicle (UAV is a nonlinear dynamic system with uncertainties and noises. Therefore, an appropriate control system has an obligation to ensure the stabilization and navigation of UAV. This paper mainly discusses the control problem of quad-rotor UAV system, which is influenced by unknown parameters and noises. Besides, a sliding mode control based on online adaptive error compensation support vector machine (SVM is proposed for stabilizing quad-rotor UAV system. Sliding mode controller is established through analyzing quad-rotor dynamics model in which the unknown parameters are computed by offline SVM. During this process, the online adaptive error compensation SVM method is applied in this paper. As modeling errors and noises both exist in the process of flight, the offline SVM one-time mode cannot predict the uncertainties and noises accurately. The control law is adjusted in real-time by introducing new training sample data to online adaptive SVM in the control process, so that the stability and robustness of flight are ensured. It can be demonstrated through the simulation experiments that the UAV that joined online adaptive SVM can track the changing path faster according to its dynamic model. Consequently, the proposed method that is proved has the better control effect in the UAV system.

  3. Modified Adaptive Control for Region 3 Operation in the Presence of Wind Turbine Structural Modes

    Science.gov (United States)

    Frost, Susan Alane; Balas, Mark J.; Wright, Alan D.

    2010-01-01

    Many challenges exist for the operation of wind turbines in an efficient manner that is reliable and avoids component fatigue and failure. Turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, possibly causing component fatigue and failure. Wind turbine manufacturers are highly motivated to reduce component fatigue and failure that can lead to loss of revenue due to turbine down time and maintenance costs. The trend in wind turbine design is toward larger, more flexible turbines that are ideally suited to adaptive control methods due to the complexity and expense required to create accurate models of their dynamic characteristics. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the excitation of structural modes in the wind turbine. The control objective is accomplished by collectively pitching the turbine blades. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. The adaptive controller will demonstrate the ability to regulate generator speed in Region 3, while accommodating gusts, and reducing the excitation of certain structural modes in the wind turbine.

  4. School travel mode, parenting practices and physical activity among UK Year 5 and 6 children

    OpenAIRE

    Jago, Russell; Wood, Lesley; Sebire, Simon J; Edwards, Mark J.; Davies, Ben; Banfield, Kathryn; Fox, Kenneth R; Thompson, Janice L.; Cooper, Ashley R.; Montgomery, Alan A

    2014-01-01

    Background School travel mode and parenting practices have been associated with children’s physical activity (PA). The current study sought to examine whether PA parenting practices differ by school travel mode and whether school travel mode and PA parenting practices are associated with PA. Methods 469 children (aged 9-11) wore accelerometers from which mean weekday and after-school (3.30 to 8.30 pm) minutes of moderate-to-vigorous intensity PA (MVPA) and counts per minute (CPM) were derived...

  5. Different cell death modes of pancreatic acinar cells on macrophage activation in rats

    Institute of Scientific and Technical Information of China (English)

    LIANG Tao; LIU Tie-fu; XUE Dong-bo; SUN Bei; SHI Li-jun

    2008-01-01

    Background The pathogenesis of acute pancreatitis is complex and largely unclear. The aim of this study was to explore the relationship between modes of cell death in pancreatic acinar cells, the release of cell contents and the inflammatory response of macrophagas.Methods Our experiment included four groups: group A (the control group), group B (AR42J cells overstimulated by caerulein), group C (AR42J cells treated with lipopolysaccharide and caerulein), and group D (AR42J cells treated with octreotide and caerulein). Apoptosis and oncosis, and the release of amylase and lactate dehydrogenase (LDH) from AR42J cells were detected. Rat macrophages were stimulated by 1 ml supematant of culture medium of AR42J cells.Finally, NF-кB activation and TNF-α and IL-1β secretion by macrophages were detected.Results Oncotlc cells in group C increased while apoptctic cells decreased (P <0.05); cells in group D had the inverse reaction. The release of amylase and LDH changed directly with the occurrence of oncosis. The transcription factor NF-кB was activated and secretion of TNF-α and IL-1β were significantly higher in group C than in group B (P <0.05); in group D, these actions were significantly lower than in group B (P<0.05). This trend was in line with changes in amylase and LDH production.Conclusion There is a close relationship between modes of pancreatic acinar cell death, the release of cell contents and the inflammatory reaction of macrophages.

  6. Asymptotic Stability for Coupled Modal Sliding Mode Control of Vibration in a Flexible Structure

    Directory of Open Access Journals (Sweden)

    Ming-Chang Pai

    2009-01-01

    Full Text Available This paper deals with the asymptotic stability of the coupled modal sliding mode control of a vibratory structure in the presence of parametric uncertainties. The method is based on the linear fractional transformation and the small gain theorem / μ analysis. Using a flexible tetrahedral truss structure, a numerical example is presented to verify the theoretical analysis.

  7. Sliding Mode Control of PMSG Wind Turbine Based on Enhanced Exponential Reaching Law

    DEFF Research Database (Denmark)

    Mozayan, Seyed Mehdi; Saad, Maarouf; Fortin-Blanchette, Handy;

    2016-01-01

    This paper proposes a Sliding Mode Control (SMC) based scheme for a variable speed, direct-driven Wind Energy Conversion Systems (WECS) equipped with Permanent Magnet Synchronous Generator (PMSG) connected to the grid. In this work, diode rectifier, boost converter, Neutral Point Clamped (NPC...

  8. Simultaneous Infrared Dry-Blanching and Dehydration of apple slices Controlled by Intermittent Heating Mode

    Science.gov (United States)

    Infrared heating controlled by intermittent heating mode was found to be able to achieve simultaneous dry-blanching and dehydration of apple slices with a desirable quality. In order to better understand the performance of intermittent heating for simultaneous dry-blanching and dehydration (SIDBD),...

  9. Noise characterization of a pulse train generated by actively mode-locked lasers

    OpenAIRE

    Eliyahu, Danny; Salvatore, Randal A.; Yariv, Amnon

    1996-01-01

    We analyze the entire power spectrum of pulse trains generated by a continuously operating actively mode-locked laser in the presence of noise. We consider the effect of amplitude, pulse-shape, and timing-jitter fluctuations that are characterized by stationary processes. Effects of correlations between different parameters of these fluctuations are studied also. The nonstationary timing-jitter fluctuations of passively mode-locked lasers and their influence on the power spectrum is discussed...

  10. Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

  11. Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

    OpenAIRE

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacit...

  12. Energy harvesting from an exercise bike using a switch-mode converter controlled generator

    DEFF Research Database (Denmark)

    Knott, Arnold; Lindberg-Poulsen, Kristian; Andersen, Thomas;

    2010-01-01

    output of the bike. The complete controller design consists of this power stage, a control circuit, a startup circuit and an overvoltage protection circuit. A functional overview of the entire controller is presented in the paper, along with in-depth descriptions of the specific subcircuits designed......This paper investigates the feasibility of using an alternator as means of harvesting energy from a stationary exercise bicycle. A switch mode converter was designed to regulate the current in the alternator rotor winding, thus regulating the power required to pedal, and consequently the power....... The system is self-starting and does not require an external power source. There are two modes of operation: Voltage regulated 12V output for connection to a standard inverter, and unregulated output for charging of a 24V battery, with direct linear control of the rotor current, thus simulating road bike...

  13. Path Following of Autonomous Vehicle in 2D Space Using Multivariable Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Daxiong Ji

    2014-01-01

    Full Text Available A solution to the path following problem for underactuated autonomous vehicles in the presence of possibly large modeling parametric uncertainty is proposed. For a general class of vehicles moving in 2D space, we demonstrated a path following control law based on multiple variable sliding mode that yields global boundedness and convergence of the position tracking error to a small neighborhood and robustness to parametric modeling uncertainty. An error integration element is added into the “tanh” function of the traditional sliding mode control. We illustrated our results in the context of the vehicle control applications that an underwater vehicle moves along with the desired paths in 2D space. Simulations show that the control objectives were accomplished.

  14. Speed control of PMSM system using improved reaching law based sliding mode control and disturbance observer technique

    Directory of Open Access Journals (Sweden)

    Shital M.Wasu

    2013-12-01

    Full Text Available In this paper, improvement of transient response of the permanent-magnet synchronous motor (PMSM subjected to different level of load disturbances and parametric uncertainties and unmodeled dynamics are studied using improved reaching law sliding mode control (IRLSMC and disturbance observer techniques. Proposed scheme is tested under different load conditions and parametric uncertainties. The results of proposed reaching law are compared with other techniques to prove the effectiveness of proposed scheme. Simulation results show the efficacy of proposed control approach.

  15. Microglial control of neuronal activity

    Directory of Open Access Journals (Sweden)

    Catherine eBéchade

    2013-03-01

    Full Text Available Fine-tuning of neuronal activity was thought to be a neuron-autonomous mechanism until the discovery that astrocytes are active players of synaptic transmission. The involvement of astrocytes has changed our understanding of the roles of non-neuronal cells and shed new light on the regulation of neuronal activity. Microglial cells are the macrophages of the brain and they have been mostly investigated as immune cells. However recent data discussed in this review support the notion that, similarly to astrocytes, microglia are involved in the regulation of neuronal activity. For instance, in most, if not all, brain pathologies a strong temporal correlation has long been known to exist between the pathological activation of microglia and dysfunction of neuronal activity. Recent studies have convincingly shown that alteration of microglial function is responsible for pathological neuronal activity. This causal relationship has also been demonstrated in mice bearing loss-of-function mutations in genes specifically expressed by microglia. In addition to these long-term regulations of neuronal activity, recent data show that microglia can also rapidly regulate neuronal activity, thereby acting as partners of neurotransmission.

  16. Resistive wall mode feedback control in EXTRAP T2R with improved steady-state error and transient response

    Science.gov (United States)

    Brunsell, P. R.; Olofsson, K. E. J.; Frassinetti, L.; Drake, J. R.

    2007-10-01

    Experiments in the EXTRAP T2R reversed field pinch [P. R. Brunsell, H. Bergsåker, M. Cecconello et al., Plasma Phys. Control. Fusion 43, 1457 (2001)] on feedback control of m =1 resistive wall modes (RWMs) are compared with simulations using the cylindrical linear magnetohydrodynamic model, including the dynamics of the active coils and power amplifiers. Stabilization of the main RWMs (n=-11,-10,-9,-8,+5,+6) is shown using modest loop gains of the order G ˜1. However, other marginally unstable RWMs (n=-2,-1,+1,+2) driven by external field errors are only partially canceled at these gains. The experimental system stability limit is confirmed by simulations showing that the latency of the digital controller ˜50μs is degrading the system gain margin. The transient response is improved with a proportional-plus-derivative controller, and steady-state error is improved with a proportional-plus-integral controller. Suppression of all modes is obtained at high gain G ˜10 using a proportional-plus-integral-plus-derivative controller.

  17. Control and fault diagnosis based sliding mode observer of a multicellular converter: Hybrid approach

    KAUST Repository

    Benzineb, Omar

    2013-01-01

    In this article, the diagnosis of a three cell converter is developed. The hybrid nature of the system represented by the presence of continuous and discrete dynamics is taken into account in the control design. The idea is based on using a hybrid control and an observer-type sliding mode to generate residuals from the observation errors of the system. The simulation results are presented at the end to illustrate the performance of the proposed approach. © 2013 FEI STU.

  18. Sliding Mode Control for Nonlinear System Based on T-S Model

    Institute of Scientific and Technical Information of China (English)

    WU Zhong-qiang

    2002-01-01

    Using T-S model as an approximation for nonlinear system, the nonlinear system has been fuzzy into local linear model. The variable structure controller designed by using Lyapunov theory insures the stability of system. The sliding mode controller is designed by using unit vector style, and it suit the uncertain elements satisfying matching condition or do not satisfy matching condition. The effect of the scheme has been tasted with a simulation of an inverted pendulum.

  19. Diagnosis of Fault Modes Masked by Control Loops with an Application to Autonomous Hovercraft Systems

    OpenAIRE

    Ioannis A. Raptis; Rodney Martin; Robert Mah; Nikunj Oza; Dimitri Mavris; Sehwan Oh; Kilsoo Kim; Young-Ki Lee; Christopher Sconyers; George J. Vachtsevanos

    2013-01-01

    This paper introduces a methodology for the design, testing and assessment of incipient failure detection techniques for failing components/systems of an autonomous vehicle masked or hidden by feedback control loops. It is recognized that the optimum operation of critical assets (aircraft, autonomous systems, etc.) may be compromised by feedback control loops by masking severe fault modes while compensating for typical disturbances. Detrimental consequences of such occurrences include the ina...

  20. Mode estimation and adaptive feedforward control for stabilization of a flexible gun tube

    Science.gov (United States)

    Vandegrift, Mark W.; DiRenzo, Michael T.

    1998-07-01

    In this paper we describe an approach for designing a pointing and stabilization system for an unbalanced, flexible gun. Our approach is based upon classical control techniques as well as system identification and adaptive feedforward techniques. Adaptive algorithms identify the flexible modes of the system and estimate the dynamics unbalance. This information is used to update the control law in order to improve the stabilization accuracy of the system.

  1. Multifunctional current-mode filter with dual-parameter control of the pole frequency

    Directory of Open Access Journals (Sweden)

    JERABEK, J.

    2016-08-01

    Full Text Available This paper presents a multifunctional current-mode filter with dual-parameter control of the pole frequency. The filter is of the second order, of single-input triple-output (SITO type and a required type of the response (low pass, inverting band pass, high pass, band reject and all pass is obtained by proper selection of one or more outputs. The filter employs two capacitors, two operational transconductance amplifiers (OTAs, each of them with controllable transconductance, and two digitally adjustable current amplifiers (DACAs, providing controllable current gain. Both these controllable parameters directly influence pole frequency of the filter. The theoretical presumptions were confirmed by laboratory measurements.

  2. Development of the HIDEC inlet integration mode. [Highly Integrated Digital Electronic Control

    Science.gov (United States)

    Chisholm, J. D.; Nobbs, S. G.; Stewart, J. F.

    1990-01-01

    The Highly Integrated Digital Electronic Control (HIDEC) development program conducted at NASA-Ames/Dryden will use an F-15 test aircraft for flight demonstration. An account is presently given of the HIDEC Inlet Integration mode's design concept, control law, and test aircraft implementation, with a view to its performance benefits. The enhancement of performance is a function of the use of Digital Electronic Engine Control corrected engine airflow computations to improve the scheduling of inlet ramp positions in real time; excess thrust can thereby be increased by 13 percent at Mach 2.3 and 40,000 ft. Aircraft supportability is also improved through the obviation of inlet controllers.

  3. High temperature brushless DC motor system and its operation mode control

    Institute of Scientific and Technical Information of China (English)

    邹继斌; 胡建辉; 徐永向

    2001-01-01

    The high temperature ( 175 ℃ ) operation of a motor spells out special requirements for control algorithms, materials and elements. The stability of motor characteristic is guaranteed by the digital control strategy. Constant velocity operation is achieved by phase-locked loop ( PLL), and constant power operation is achieved by a current-restricting circuit. A motor for constant speed and constant power operation has been built and the speed control system is tuned by MATLAB simulation. Experimental and simulation results for operation mode control of brushless DC motor are presented.

  4. Fuzzy Sliding Mode Controller Design Using Takagi-Sugeno Modelled Nonlinear Systems

    Directory of Open Access Journals (Sweden)

    S. Bououden

    2013-01-01

    Full Text Available Adaptive fuzzy sliding mode controller for a class of uncertain nonlinear systems is proposed in this paper. The unknown system dynamics and upper bounds of the minimum approximation errors are adaptively updated with stabilizing adaptive laws. The closed-loop system driven by the proposed controllers is shown to be stable with all the adaptation parameters being bounded. The performance and stability of the proposed control system are achieved analytically using the Lyapunov stability theory. Simulations show that the proposed controller performs well and exhibits good performance.

  5. Developing Internal Controls through Activities

    Science.gov (United States)

    Barnes, F. Herbert

    2009-01-01

    Life events can include the Tuesday afternoon cooking class with the group worker or the Saturday afternoon football game, but in the sense that Fritz Redl thought of them, these activities are only threads in a fabric of living that includes all the elements of daily life: playing, working, school-based learning, learning through activities,…

  6. Speed Synchronization of Multi Induction Motors with Fuzzy Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    HACHEMI Glaoui

    2013-05-01

    Full Text Available A continuous web winding system is a large-scale, complex interconnected dynamic system with numerous tension zones to transport the web while processing it. There are two control schemes for large-scale system control: the centralized scheme and the decentralized scheme. Centralized control is the traditional control method, which considers all the information about the system to be a single dynamic model and design a control system for this model. Aspeed synchronization control strategy for multiple induction motors, based on adjacent cross-coupling control structure, is developed by employing total sliding mode control method. The proposed controlstrategy is to stabilize speed tracking of each induction motor while synchronizing its speed with the speed of the other motors so as to make speed synchronization error amongst induction motors converge to zero. The global stability and the convergence of the designedcontroller are proved by using Lyapunov method. Simulation results demonstrate the effectiveness of the proposed method.

  7. Higher-order sliding mode control of a diesel generator set

    Energy Technology Data Exchange (ETDEWEB)

    Goh, K.B.; Spurgeon, S.K.; Jones, B. [University of Leicester (United Kingdom). Dept. of Engineering

    2003-06-01

    Diesel engines are used as prime movers and independent power sources in many applications because of their advantages in terms of fuel efficiency, robustness and reliability. This paper presents the results of isochronous speed controller design and experimental analysis of robustness and efficiency of a turbocharged diesel generator set (genset). The steady state performance and transient response of the genset speed utilizing second-order sliding mode techniques with a super twisting sliding mode control algorithm are assessed. The algorithm does not require the time derivative of the sliding variable. It only uses the measured genset speed and does not require the use of an observer. A modification made to the algorithm shows improvement of the genset performance over a wide operating envelope. The influence of this methodology and modification of the algorithm on overall generator performance, in particular in the presence of large load changes and in terms of fuel efficiency, exhaust emissions, starting speed transient response and steady speed variation, are assessed. An algorithm for tuning the higher-order sliding mode (HOSM) controller for the genset is established and presented. The robustness of the controller is investigated and the performance is compared with that obtained by a commercial genset controller and a classical proportional-integral controller. (author)

  8. Robust fuzzy neural network sliding mode control scheme for IPMSM drives

    Science.gov (United States)

    Leu, V. Q.; Mwasilu, F.; Choi, H. H.; Lee, J.; Jung, J. W.

    2014-07-01

    This article proposes a robust fuzzy neural network sliding mode control (FNNSMC) law for interior permanent magnet synchronous motor (IPMSM) drives. The proposed control strategy not only guarantees accurate and fast command speed tracking but also it ensures the robustness to system uncertainties and sudden speed and load changes. The proposed speed controller encompasses three control terms: a decoupling control term which compensates for nonlinear coupling factors using nominal parameters, a fuzzy neural network (FNN) control term which approximates the ideal control components and a sliding mode control (SMC) term which is proposed to compensate for the errors of that approximation. Next, an online FNN training methodology, which is developed using the Lyapunov stability theorem and the gradient descent method, is proposed to enhance the learning capability of the FNN. Moreover, the maximum torque per ampere (MTPA) control is incorporated to maximise the torque generation in the constant torque region and increase the efficiency of the IPMSM drives. To verify the effectiveness of the proposed robust FNNSMC, simulations and experiments are performed by using MATLAB/Simulink platform and a TI TMS320F28335 DSP on a prototype IPMSM drive setup, respectively. Finally, the simulated and experimental results indicate that the proposed design scheme can achieve much better control performances (e.g. more rapid transient response and smaller steady-state error) when compared to the conventional SMC method, especially in the case that there exist system uncertainties.

  9. Application of Adaptive Backstepping Sliding Mode Control in Alternative Current Servo System of Rocket Launcher%Application of Adaptive Backstepping Sliding Mode Control in Alternative Current Servo System of Rocket Launcher

    Institute of Scientific and Technical Information of China (English)

    郭亚军; 马大为; 王晓峰; 乐贵高

    2011-01-01

    An adaptive backstepping sliding mode control approach is introduced to control the pitch motion of a rocket launcher. Its control law is proposed to guarantee that the control system is ultimately bounded in a Lyapunov sense and make the servo system track the instruction of reference position globally and asymptotically. In addition, the sliding mode control can restrain the effects of parameter uncertainties and external disturbance. The functions of adaptive mechanism and sliding mode control are analyzed through the simulation in the different conditions. The simulation results illustrate that the method is applicable and robust.

  10. Vibration control of active structures an introduction

    CERN Document Server

    Preumont, Andre

    2002-01-01

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

  11. Multiple dynamo modes as a mechanism for long-term solar activity variations

    Science.gov (United States)

    Käpylä, M. J.; Käpylä, P. J.; Olspert, N.; Brandenburg, A.; Warnecke, J.; Karak, B. B.; Pelt, J.

    2016-05-01

    Context. Solar magnetic activity shows both smooth secular changes, such as the modern Grand Maximum, and quite abrupt drops that are denoted as grand minima, such as the Maunder Minimum. Direct numerical simulations (DNS) of convection-driven dynamos offer one way of examining the mechanisms behind these events. Aims: In this work, we analyze a solution of a solar-like DNS that was evolved for roughly 80 magnetic cycles of 4.9 years and where epochs of irregular behavior are detected. The emphasis of our analysis is to find physical causes for such behavior. Methods: The DNS employed is a semi-global (wedge-shaped) magnetoconvection model. For the data analysis tasks we use Ensemble Empirical Mode Decomposition and phase dispersion methods, as they are well suited for analyzing cyclic (non-periodic) signals. Results: A special property of the DNS is the existence of multiple dynamo modes at different depths and latitudes. The dominant mode is solar-like (equatorward migration at low latitudes and poleward at high latitudes). This mode is accompanied by a higher frequency mode near the surface and at low latitudes, showing poleward migration, and a low-frequency mode at the bottom of the convection zone. The low-frequency mode is almost purely antisymmetric with respect to the equator, while the dominant mode has strongly fluctuating mixed parity. The overall behavior of the dynamo solution is extremely complex, exhibiting variable cycle lengths, epochs of disturbed and even ceased surface activity, and strong short-term hemispherical asymmetries. Surprisingly, the most prominent suppressed surface activity epoch is actually a global magnetic energy maximum; during this epoch the bottom toroidal magnetic field obtains a maximum, demonstrating that the interpretation of grand minima-type events is non-trivial. The hemispherical asymmetries are seen only in the magnetic field, while the velocity field exhibits considerably weaker asymmetry. Conclusions: We interpret

  12. Complete bifurcation analysis of DC-DC converters under current mode control

    Science.gov (United States)

    Pikulin, D.

    2014-03-01

    The purpose of this research is to investigate to what extend application of novel method of complete bifurcation groups to the analysis of global dynamics of piecewise-smooth hybrid systems enables one to highlight new nonlinear effects before periodic and chaotic regimes. Results include the construction of complete one and two-parameter bifurcation diagrams, detection of various types of bifurcation groups and investigation of their interactions, localization of rare attractors, and the investigation of different principles of birth of chaotic attractors. Effectiveness of the approach is illustrated in respect to one of the most widely used switching systems-boost converter under current mode control operating in continuous current mode.

  13. Higher order mode excitation in eccentric active nano-particles for tailoring of the near-field radiation

    DEFF Research Database (Denmark)

    Thorsen, R. O.; Arslanagic, Samel

    2015-01-01

    We examine the excitation of resonant modes inside eccentrically layered cylindrical active nano-particles. The nano-particle is a three-layer structure comprised of a silica core, a free-space middle layer, and an outer shell of silver. It is shown that a concentric configuration, initially desi...... of the gain constant, is shown to be controlled by the direction of the core displacement. The present eccentric active nano-particles may provide alternative strategies for directive near-field radiation relative to the existing designs....

  14. Carrier-Based Common Mode Voltage Control Techniques in Three-Level Diode-Clamped Inverter

    Directory of Open Access Journals (Sweden)

    Pradyumn Chaturvedi

    2012-01-01

    Full Text Available Switching converters are used in electric drive applications to produce variable voltage, variable frequency supply which generates harmful large dv/dt and high-frequency common mode voltages (CMV. Multilevel inverters generate lower CMV as compared to conventional two-level inverters. This paper presents simple carrier-based technique to control the common mode voltages in multilevel inverters using different structures of sine-triangle comparison method such as phase disposition (PD, phase opposition disposition (POD by adding common mode voltage offset signal to actual reference voltage signal. This paper also presented the method to optimize the magnitude of this offset signal to reduce CMV and total harmonic distortion in inverter output voltage. The presented techniques give comparable performance as obtained in complex space vector-based control strategy, in terms of number of commutations, magnitude, and rate of change of CMV and harmonic profile of inverter output voltage. Simulation and experimental results presented confirm the effectiveness of the proposed techniques to control the common mode voltages.

  15. Broad spectrum antibacterial and antifungal polymeric paint materials: synthesis, structure-activity relationship, and membrane-active mode of action.

    Science.gov (United States)

    Hoque, Jiaul; Akkapeddi, Padma; Yadav, Vikas; Manjunath, Goutham B; Uppu, Divakara S S M; Konai, Mohini M; Yarlagadda, Venkateswarlu; Sanyal, Kaustuv; Haldar, Jayanta

    2015-01-28

    Microbial attachment and subsequent colonization onto surfaces lead to the spread of deadly community-acquired and hospital-acquired (nosocomial) infections. Noncovalent immobilization of water insoluble and organo-soluble cationic polymers onto a surface is a facile approach to prevent microbial contamination. In the present study, we described the synthesis of water insoluble and organo-soluble polymeric materials and demonstrated their structure-activity relationship against various human pathogenic bacteria including drug-resistant strains such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and beta lactam-resistant Klebsiella pneumoniae as well as pathogenic fungi such as Candida spp. and Cryptococcus spp. The polymer coated surfaces completely inactivated both bacteria and fungi upon contact (5 log reduction with respect to control). Linear polymers were more active and found to have a higher killing rate than the branched polymers. The polymer coated surfaces also exhibited significant activity in various complex mammalian fluids such as serum, plasma, and blood and showed negligible hemolysis at an amount much higher than minimum inhibitory amounts (MIAs). These polymers were found to have excellent compatibility with other medically relevant polymers (polylactic acid, PLA) and commercial paint. The cationic hydrophobic polymer coatings disrupted the lipid membrane of both bacteria and fungi and thus showed a membrane-active mode of action. Further, bacteria did not develop resistance against these membrane-active polymers in sharp contrast to conventional antibiotics and lipopeptides, thus the polymers hold great promise to be used as coating materials for developing permanent antimicrobial paint. PMID:25541751

  16. Second Order Sliding Mode Control Scheme for an Autonomous Underwater Vehicle with Dynamic Region Concept

    Directory of Open Access Journals (Sweden)

    Zool H. Ismail

    2015-01-01

    Full Text Available The main goal in developing closed loop control system for an Autonomous Underwater Vehicle (AUV is to make a robust vehicle from natural and exogenous perturbations such as wind, wave, and ocean currents. However a well-known robust control, for instance, Sliding Mode Controller (SMC, gives a chattering effect and it influences the stability of an AUV. Furthermore, some researchers combined other controls to get better result but it tends to present long computational time and causes large energy consumption. Thus, this paper proposed a Super Twisting Sliding Mode Controller (STSMC with dynamic region concept for an AUV. STSMC or a second order SMC is adopted as a robust controller which is free from chattering effect. Meanwhile, the implementation of dynamic region is useful to reduce the energy usage. As a result, the proposed controller obtains global asymptotic stability which is validated by using Lyapunov-like function. Moreover, some simulations present the efficiency of proposed controller. In conclusion, STSMC with region based control is effective to be applied for the robust tracking of an AUV. It contributes to give a fast response when handling the perturbations, short computational time, and low energy demand.

  17. Robust Graded Sliding Mode Tracking Control for Low Speed Spinning Ballistic Missiles

    Institute of Scientific and Technical Information of China (English)

    ZHOU Jun; WANG Zhi; ZHOU Feng-qi

    2007-01-01

    The nonlinear dynamic model of spinning ballistic missiles is established during the first boosting phase of the missile. Based on the conventional backstepping sliding mode control and the assumption of a two time-scale separation of missile dynamics, a graded sliding mode controller is designed with two sub-sliding surfaces which have invariability to external disturbances and parameter perturbations, and a matrix which comprises three first order low pass filters is introduced to prevent "explosion of terms". Owing to the upper bounds of the uncertainties are difficult to obtain in advance,adaptive laws are introduced to estimate the values of the uncertainties in real-time. Eventually, the numerical simulation results given to show the proposed controller can ensure the steady flight of missiles.

  18. Position Sensorless Control for Permanent Magnet Synchronous Motor Using Sliding Mode Observer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    An approach of position sensorless control for permanent magnet synchronous motor (PMSM) is put forward based on a sliding mode observer. The mathematical model of PMSM in a stationary αβ reference frame is adopted, and the system is controlled by the digital signal processor (DSP) TMS320LF2407 according to the control theory of sliding mode observer. In order to achieve closed loop operation of the motor, the stator magnetic field should be vertical with the rotor magnetic field and be synchronous with rotor rotating, so the position and speed of PMSM is estimated in real time and the estimated position is modified continuously. The simulation results indicate that the proposed observer has high precision in estimation of PMSM position and speed, and is more robust to the parametric variation and load torque disturbance.

  19. Implementation of model predictive control for resistive wall mode stabilization on EXTRAP T2R

    Science.gov (United States)

    Setiadi, A. C.; Brunsell, P. R.; Frassinetti, L.

    2015-10-01

    A model predictive control (MPC) method for stabilization of the resistive wall mode (RWM) in the EXTRAP T2R reversed-field pinch is presented. The system identification technique is used to obtain a linearized empirical model of EXTRAP T2R. MPC employs the model for prediction and computes optimal control inputs that satisfy performance criterion. The use of a linearized form of the model allows for compact formulation of MPC, implemented on a millisecond timescale, that can be used for real-time control. The design allows the user to arbitrarily suppress any selected Fourier mode. The experimental results from EXTRAP T2R show that the designed and implemented MPC successfully stabilizes the RWM.

  20. Real-time reflectometry measurement validation in H-mode regimes for plasma position control

    International Nuclear Information System (INIS)

    It has been shown that in H-mode regimes, reflectometry electron density profiles and an estimate for the density at the separatrix can be jointly used to track the separatrix within the precision required for plasma position control on ITER. We present a method to automatically remove, from the position estimation procedure, measurements performed during collapse and recovery phases of edge localized modes (ELMs). Based on the rejection mechanism, the method also produces an estimate confidence value to be fed to the position feedback controller. Preliminary results show that the method improves the real-time experimental separatrix tracking capabilities and has the potential to eliminate the need for an external online source of ELM event signaling during control feedback operation.

  1. Diagnosis of Fault Modes Masked by Control Loops with an Application to Autonomous Hovercraft Systems

    Directory of Open Access Journals (Sweden)

    Ioannis A. Raptis

    2013-01-01

    Full Text Available This paper introduces a methodology for the design, testing and assessment of incipient failure detection techniques for failing components/systems of an autonomous vehicle masked or hidden by feedback control loops. It is recognized that the optimum operation of critical assets (aircraft, autonomous systems, etc. may be compromised by feedback control loops by masking severe fault modes while compensating for typical disturbances. Detrimental consequences of such occurrences include the inability to detect expeditiously and accurately incipient failures, loss of control and inefficient operation of assets in the form of fuel overconsumption and adverse environmental impact. We pursue a systems engineering process to design, construct and test an autonomous hovercraft instrumented appropriately for improved autonomy. Hidden fault modes are detected with performance guarantees by invoking a Bayesian estimation approach called particle filtering. Simulation and experimental studies are employed to demonstrate the efficacy of the proposed methods.

  2. Using speech for mode selection in control of multifunctional myoelectric prostheses.

    Science.gov (United States)

    Fang, Peng; Wei, Zheng; Geng, Yanjuan; Yao, Fuan; Li, Guanglin

    2013-01-01

    Electromyogram (EMG) recorded from residual muscles of limbs is considered as suitable control information for motorized prostheses. However, in case of high-level amputations, the residual muscles are usually limited, which may not provide enough EMG for flexible control of myoelectric prostheses with multiple degrees of freedom of movements. Here, we proposed a control strategy, where the speech signals were used as additional information and combined with the EMG signals to realize more flexible control of multifunctional prostheses. By replacing the traditional "sequential mode-switching (joint-switching)", the speech signals were used to select a mode (joint) of the prosthetic arm, and then the EMG signals were applied to determine a motion class involved in the selected joint and to execute the motion. Preliminary results from three able-bodied subjects and one transhumeral amputee demonstrated the proposed strategy could achieve a high mode-selection rate and enhance the operation efficiency, suggesting the strategy may improve the control performance of commercial myoelectric prostheses.

  3. RESEARCH ON GEAR SHIFTING PROCESS IN COMMAND MODE OF VEHICLE POWERTRAIN CONTROL

    Directory of Open Access Journals (Sweden)

    V. A. Kusyak

    2014-01-01

    Full Text Available The paper presents a schematic diagram of the powertrain automated control system based on dry friction clutch and manual gearbox. Mechatronic system has a modular configuration and allows to make the vehicle starting-up, low speed maneuvering and command or automatic gearshifting. Diesel engine, clutch and 10-step gearbox control is carried out at all movement modes by electronic modules when affected on mode selector, accelerator pedal and, if necessary, on brake pedal. Data exchange between electronic units is carried by SAE-J1939 protocol with a transmission rate of 250 kbit/s. Change in diesel fuel supply, clutch engagement and gearshifting take place automatically as a result of pneumatic power actuator operation by a signal from the controller to the corresponding solenoid valve or a combination thereof.Presents the results of semi-natural experiment on research of gear shifting process in the command mode of powertrain control. Transient gearshift oscillograms with various control algorithm structure have been given in the paper. The paper contains a ^iT^rative analysis of the oscillograma and a conclusion on expediency of gear shifting automation. A graphic representation of the semi-natural experiment results has been performed with the help of CoDeSys V2.3-visualization facilities.

  4. Using speech for mode selection in control of multifunctional myoelectric prostheses.

    Science.gov (United States)

    Fang, Peng; Wei, Zheng; Geng, Yanjuan; Yao, Fuan; Li, Guanglin

    2013-01-01

    Electromyogram (EMG) recorded from residual muscles of limbs is considered as suitable control information for motorized prostheses. However, in case of high-level amputations, the residual muscles are usually limited, which may not provide enough EMG for flexible control of myoelectric prostheses with multiple degrees of freedom of movements. Here, we proposed a control strategy, where the speech signals were used as additional information and combined with the EMG signals to realize more flexible control of multifunctional prostheses. By replacing the traditional "sequential mode-switching (joint-switching)", the speech signals were used to select a mode (joint) of the prosthetic arm, and then the EMG signals were applied to determine a motion class involved in the selected joint and to execute the motion. Preliminary results from three able-bodied subjects and one transhumeral amputee demonstrated the proposed strategy could achieve a high mode-selection rate and enhance the operation efficiency, suggesting the strategy may improve the control performance of commercial myoelectric prostheses. PMID:24110509

  5. Sliding Mode Implementation of an Attitude Command Flight Control System for a Helicopter in Hover

    Directory of Open Access Journals (Sweden)

    D. J. McGeoch

    2005-01-01

    Full Text Available This paper presents an investigation into the design of a flight control system, using a decoupled non-linear sliding mode control structure, designed using a linearised, 9th order representation of the dynamics of a PUMA helicopter in hover. The controllers are then tested upon a higher order, non-linear helicopter model, called RASCAL. This design approach is used for attitude command flight control implementation and the control performance is assessed in the terms of handling qualities through the Aeronautical Design Standards for Rotorcraft (ADS-33. In this context a linearised approximation of the helicopter system is used to design an SMC control scheme. These controllers have been found to yield a system that satisfies the Level 1 handling qualities set out by ADS-33. 

  6. Adaptive sliding mode control of interleaved parallel boost converter for fuel cell energy generation system

    DEFF Research Database (Denmark)

    El Fadil, H.; Giri, F.; Guerrero, Josep M.

    2013-01-01

    This paper deals with the problem of controlling energy generation systems including fuel cells (FCs) and interleaved boost power converters. The proposed nonlinear adaptive controller is designed using sliding mode control (SMC) technique based on the system nonlinear model. The latter accounts...... for the boost converter large-signal dynamics as well as for the fuel-cell nonlinear characteristics. The adaptive nonlinear controller involves online estimation of the DC bus impedance ‘seen’ by the converter. The control objective is threefold: (i) asymptotic stability of the closed loop system......, (ii) output voltage regulation under bus impedance uncertainties and (iii) equal current sharing between modules. It is formally shown, using theoretical analysis and simulations, that the developed adaptive controller actually meets its control objectives....

  7. Decentralized sliding-mode control for spacecraft attitude synchronization under actuator failures

    Science.gov (United States)

    Wu, Baolin; Wang, Danwei; Poh, Eng Kee

    2014-12-01

    This paper examines attitude synchronization and tracking problems with model uncertainties, external disturbances, actuator failures and control torque saturation. Two decentralized sliding mode control laws are proposed and analyzed based on algebraic graph theory. Using Barbalat's Lemma, it is shown that the control laws guarantee each spacecraft approaches the desired time-varying attitude and angular velocity while maintaining attitude synchronization among the other spacecraft in the formation. The first controller is designed in the presence of model uncertainties, external disturbances, and actuator failures. The results are extended to the case with control input saturation in the second controller. Both control laws do not require online identification of failures. Numerical simulations are presented to show the effectiveness of the proposed attitude synchronization and tracking approaches.

  8. Controlled excitation of electromagnetic band-gap line and point defect modes at microwave frequencies

    Science.gov (United States)

    Schuster, M.; Klein, N.

    2003-03-01

    We report on the controlled excitation of line and point defect modes in a two-dimensional hexagonal electromagnetic band-gap structure made of rods of dielectric material (aluminium oxide). We compared simulation performed with a numerical field simulation software and experimental measurements at microwave frequencies with regard to coupling from external waveguides to line defects and subsequent coupling to resonant modes. We observed that for a line defect in the photonic crystal the impedance matching to a waveguide is strongly dependent on the defect width. We furthermore demonstrated that the coupling to a localized defect resonance can be strongly influenced by the variation of certain single lattice elements, affecting transmission behavior and quality factor of the resonant modes.

  9. Vertical cavity surface emitting laser transverse mode and polarization control by elliptical hole photonic crystal

    Institute of Scientific and Technical Information of China (English)

    Cao Tian; Xu Chen; Xie Yi-Yang; Kan Qiang; Wei Si-Min; Mao Ming-Ming; Chen Hong-Da

    2013-01-01

    The polarization of traditional photonic crystal (PC) vertical cavity surface emitting laser (VCSEL) is uncontrollable,resulting in the bit error increasing easily.Elliptical hole photonic crystal can control the transverse mode and polarization of VCSEL efficiently.We analyze the far field divergence angle,and birefringence of elliptical hole PC VCSEL.When the ratio of minor axis to major axis b/a =0.7,the PC VCSEL can obtain single mode and polarization.According to the simulation results,we fabricate the device successfully.The output power is 1.7 mW,the far field divergence angle is less than 10°,and the side mode suppression ratio is over 30 dB.The output power in the Y direction is 20 times that in the X direction.

  10. Simulation of speed control in acceleration mode of a heavy duty vehicle; Ogatasha no kasokuji ni okeru shasoku seigyo simulation

    Energy Technology Data Exchange (ETDEWEB)

    Endo, S.; Ukawa, H. [Isuzu Advanced Engineering Center, Ltd., Tokyo (Japan); Sanada, K.; Kitagawa, A. [Tokyo Institute of Technology, Tokyo (Japan)

    1997-10-01

    A control law of speed of a heavy duty vehicle in acceleration mode is presented, which is an extended version of a control law in deceleration mode proposed by the authors. The control law is based on constant acceleration strategy. Using the control law, target velocity and target distance can be performed. Both control laws for acceleration and deceleration mode can be represented by a unified mathematical formulae. Some simulation results are shown to demonstrate the control performance. 7 refs., 9 figs., 2 tabs.

  11. An Improved Production Activity Control Architecture for Shop Floor Control

    Institute of Scientific and Technical Information of China (English)

    SHAHIDIkramullahButt; SUNHou-fang; HAMIDUllahKhanNiazi

    2005-01-01

    This paper presents a further improved Production Activity Control Architecture to deal with the complexity of information by creating Sub-Producers and Sub-Movers which will not only give a better control at workstation level but also reduce load on the Dispatcher. It also makes an analysis of the basic and improved PAC (Production Activity Control) Architecture in the Control System for Integrated Manufacturing. The PAC Architecture and the improvement will further enhance the flexibility and adaptability of the architecture in the ever changing environment of the Shop Floor Control (SFC) Systems.

  12. Sliding Mode Controller Design for Position and Speed Control of Flight Simulator Servo System with Large Friction

    Institute of Scientific and Technical Information of China (English)

    刘金琨; 尔联洁

    2003-01-01

    Flight simulator is an important device and a typical high-performance position and speed servo system used in the hardware-in-the-loop simulation of flight control system. Friction is the main nonlinear resistance in the flight simulator servo system, especially in a low-speed state. Based on the description of dynamic and static models of a nonlinear Stribeck friction model, this paper puts forward sliding mode controller to overcome the friction, whose stability is proved. Simulation example indicates that the controller can guarantee a high robust performance and have a high precision of position tracking and speed tracking for a flight simulator servo system.

  13. Novel design of low-jitter 10 GHz all-active monolithic mode-locked lasers

    DEFF Research Database (Denmark)

    Larsson, David; Yvind, Kresten; Christiansen, Lotte Jin;

    2004-01-01

    Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared.......Using a novel design, we have fabricated 10 GHz all-active monolithic mode-locked semiconductor lasers that generate 1.4 ps pulses with record-low timing jitter. The dynamical properties of lasers with 1 and 2 QWs are compared....

  14. Sliding mode based fault detection, reconstruction and fault tolerant control scheme for motor systems.

    Science.gov (United States)

    Mekki, Hemza; Benzineb, Omar; Boukhetala, Djamel; Tadjine, Mohamed; Benbouzid, Mohamed

    2015-07-01

    The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper proposes an improved faults detection, reconstruction and fault-tolerant control (FTC) scheme for motor systems (MS) with typical faults. For this purpose, a sliding mode controller (SMC) with an integral sliding surface is adopted. This controller can make the output of system to track the desired position reference signal in finite-time and obtain a better dynamic response and anti-disturbance performance. But this controller cannot deal directly with total system failures. However an appropriate combination of the adopted SMC and sliding mode observer (SMO), later it is designed to on-line detect and reconstruct the faults and also to give a sensorless control strategy which can achieve tolerance to a wide class of total additive failures. The closed-loop stability is proved, using the Lyapunov stability theory. Simulation results in healthy and faulty conditions confirm the reliability of the suggested framework. PMID:25747198

  15. Adaptive Integral-type Sliding Mode Control for Spacecraft Attitude Maneuvering Under Actuator Stuck Failures

    Institute of Scientific and Technical Information of China (English)

    HU Qinglei; ZHANG Youmin; HUO Xing; XIAO Bing

    2011-01-01

    A fault tolerant control (FTC) design technique against actuator stuck faults is investigated using integral-type sliding mode control (ISMC) with application to spacecraft attitude maneuvering control system. The principle of the proposed FTC scheme is to design an integral-type sliding mode attitude controller using on-line parameter adaptive updating law to compensate for the effects of stuck actuators. This adaptive law also provides both the estimates of the system parameters and external disturbances such that a prior knowledge of the spacecraft inertia or boundedness of disturbances is not required. Moreover, by including the integral feedback term, the designed controller can not only tolerate actuator stuck faults, but also compensate the disturbances with constant components. For the synthesis of controller, the fault time, patterns and values are unknown in advance, as motivated from a practical spacecraft control application. Complete stability and performance analysis are presented and illustrative simulation results of application to a spacecraft show that high precise attitude control with zero steady-error is successfully achieved using various scenarios of stuck failures in actuators.

  16. PSO-based Control Algorithm for Polarization Mode Dispersion Self-adaptive Compensation

    Institute of Scientific and Technical Information of China (English)

    ZHU Jin-jun; ZHANG Xiao-guang; DUAN Gao-yan; WANG Qiu-guo

    2006-01-01

    Polarization mode dispersion(PMD) is considered to be the ultimate limitation in high-speed optical fiber communication systems. Establishing an effective control algorithm for adaptive PMD compensation is a challenging task, because PMD possesses the time-varying and statistical properties. The particle swarm optimization(PSO) algorithm is introduced into self-adaptive PMD compensation as feedback control algorithm. The experiment results show that PSO-based control algorithm has some unique features of rapid convergence to the global optimum without being trapped in local sub-optima and good robustness to noise in the optical fiber transmission line that has never been achieved in PMD compensation before.

  17. Research on Corporate Right of Control:Mode of Arrangement and Innovation of Governance

    Institute of Scientific and Technical Information of China (English)

    瞿宝忠

    2004-01-01

    The mode of arrangement and innovation of governance for corporate rights of control should be in accordance with the global resource disposition opportunities and efficiency competition. Based on rights formulated by acts and regulations, this paper establishes models of arrangement for corporate rights of control, and then analyses the composite basic features derived from the models. To conclude, a main frame for the arrangement and innovation of corporate rights of control is put forward based on the real practice of listed companies in China.

  18. Drag-based composite super-twisting sliding mode control law design for Mars entry guidance

    Science.gov (United States)

    Zhao, Zhenhua; Yang, Jun; Li, Shihua; Guo, Lei

    2016-06-01

    In this paper, the drag-based trajectory tracking guidance problem is investigated for Mars entry vehicle subject to uncertainties. A composite super twisting sliding mode control method based on finite-time disturbance observer is proposed for guidance law design. The proposed controller not only eliminates the effects of matched and mismatched disturbances due to uncertainties of atmospheric models and vehicle aerodynamics but also guarantees the continuity of control action. Numerical simulations are carried out on the basis of Mars Science Laboratory mission, where the results show that the proposed methods can improve the Mars entry guidance precision as compared with some existing guidance methods including PID and ADRC.

  19. Control of subsynchronous resonant modes in a series compensated system through superconducting magnetic energy storage units

    Energy Technology Data Exchange (ETDEWEB)

    Rahim, A.H.M.A.; Mohammad, A.M.; Khan, M.R. [Univ. of Bahrain, Isa Town (Bahrain). Dept. of Electrical Engineering

    1996-03-01

    A simple and novel strategy for damping subsynchronous resonant oscillations through control of converter firing angles of a superconducting magnetic energy storage system (SMES) is proposed. The strategy is derived such that the current injected or drawn by the SMES compensates for any deviation in real and reactive power in the system. The proposed control has been tested on the IEEE second benchmark model for subsynchronous resonance studies. It has been found to eliminate the slowly growing transients resulting from the unstable modes very effectively. The control algorithm is simple and its realization will require very little hardware.

  20. Attitude Analysis and Robust Adaptive Backstepping Sliding Mode Control of Spacecrafts Orbiting Irregular Asteroids

    Directory of Open Access Journals (Sweden)

    Chunhui Liang

    2014-01-01

    Full Text Available Attitude stability analysis and robust control algorithms for spacecrafts orbiting irregular asteroids are investigated in the presence of model uncertainties and external disturbances. Rigid spacecraft nonlinear attitude models are considered and detailed attitude stability analysis of spacecraft subjected to the gravity gradient torque in an irregular central gravity field is included in retrograde orbits and direct orbits using linearized system model. The robust adaptive backstepping sliding mode control laws are designed to make the attitude of the spacecrafts stabilized and responded accurately to the expectation in the presence of disturbances and parametric uncertainties. Numerical simulations are included to illustrate the spacecraft performance obtained using the proposed control laws.