Advanced stability theory analyses for laminar flow control
Orszag, S. A.
1980-01-01
Recent developments of the SALLY computer code for stability analysis of laminar flow control wings are summarized. Extensions of SALLY to study three dimensional compressible flows, nonparallel and nonlinear effects are discussed.
Advanced Adaptive Particle Swarm Optimization based SVC Controller for Power System Stability
Poonam Singhal
2014-12-01
Full Text Available The interconnected systems is continually increasing in size and extending over whole geographical regions, it is becoming increasingly more difficult to maintain synchronism between various parts of the power system. This paper work presents an advanced adaptive Particle swarm optimization technique to optimize the SVC controller parameters for enhancement of the steady state stability & overcoming the premature convergence & stagnation problems as in basic PSO algorithm & Particle swarm optimization with shrinkage factor & inertia weight approach (PSO-SFIWA. In this paper SMIB system along with PID damped SVC controller is considered for study. The generator speed deviation is used as an auxiliary signal to SVC, to generate the desired damping. This controller improves the dynamic performance of power system by reducing the steady-state error. The controller parameters are optimized using basic PSO, PSO-SFIWA & Advanced Adaptive PSO. Computational results show that Advanced Adaptive based SVC controller is able to find better quality solution as compare to conventional PSO & PSO-SFIWA Techniques.
Rigsby, James Michael
Interest in high speed rotorcraft has directed attention toward the slowed-rotor, high advance ratio compound autogyro concept as evidenced by the current DARPA Heliplane project. The behavior of partially unloaded rotors, autorotating at high advance ratio is not well understood and numerous technical issues must be resolved before the vehicle can be realized. Autorotation in helicopters usually indicates an emergency loss of power. For the concept vehicle autorotation is the normal working state of the rotor. The necessity for a reduction in rotor speed with increasing flight speed results in high advance ratio operation where the retreating side of the rotor is dominated by the reverse flow region. Further, rotor speed changes also affect the rotor dynamics and the associated hub moments generated by cyclic flapping. The result is rotor characteristics that vary widely depending on advance ratio. In the present work, rotor behavior is characterized in terms of issues relevant to the control system conceptual design and the rotor impact on the intrinsic vehicle flight dynamics characteristics. A series of trim, stability, and control analyses, based on features inherent in the concept vehicle, are performed. Trends are identified through parametric variation of rotor operating conditions, augmented by inclusion of the sensitivities to blade mass and blade stiffness properties. In this research, non-linear models, including the rotor speed degree of freedom, were created and analyzed with FLIGHTLAB(TM) rotorcraft modeling software. Performance analysis for rotors trimmed to autorotate with zero average hub pitching and rolling moments indicates reduced rotor thrust is achieved primarily through rotor speed reduction at lower shaft incidence angle, and imposing hub moment trim constraints results in a thrust increment sign reversal with collective pitch angle above advance ratio mu ˜ 1.0. Swashplate control perturbations from trim indicate an increase in control
Jordan, Keith J.
1998-01-01
This report documents results from the NASA-Langley sponsored Euler Technology Assessment Study conducted by Lockheed-Martin Tactical Aircraft Systems (LMTAS). The purpose of the study was to evaluate the ability of the SPLITFLOW code using viscous and inviscid flow models to predict aerodynamic stability and control of an advanced fighter model. The inviscid flow model was found to perform well at incidence angles below approximately 15 deg, but not as well at higher angles of attack. The results using a turbulent, viscous flow model matched the trends of the wind tunnel data, but did not show significant improvement over the Euler solutions. Overall, the predictions were found to be useful for stability and control design purposes.
Recent Advances in Heliogyro Solar Sail Structural Dynamics, Stability, and Control Research
Wilkie, W. Keats; Warren, Jerry E.; Horta, Lucas G.; Lyle, Karen H.; Juang, Jer-Nan; Gibbs, S. Chad; Dowell, Earl H.; Guerrant, Daniel V.; Lawrence, Dale
2015-01-01
Results from recent NASA sponsored research on the structural dynamics, stability, and control characteristics of heliogyro solar sails are summarized. Specific areas under investigation include coupled nonlinear finite element analysis of heliogyro membrane blade with solar radiation pressure effects, system identification of spinning membrane structures, and solarelastic stability analysis of heliogyro solar sails, including stability during blade deployment. Recent results from terrestrial 1-g blade dynamics and control experiments on "rope ladder" membrane blade analogs, and small-scale in vacuo system identification experiments with hanging and spinning high-aspect ratio membranes will also be presented. A low-cost, rideshare payload heliogyro technology demonstration mission concept is used as a mission context for these heliogyro structural dynamics and solarelasticity investigations, and is also described. Blade torsional dynamic response and control are also shown to be significantly improved through the use of edge stiffening structural features or inclusion of modest tip masses to increase centrifugal stiffening of the blade structure. An output-only system identification procedure suitable for on-orbit blade dynamics investigations is also developed and validated using ground tests of spinning sub-scale heliogyro blade models. Overall, analytical and experimental investigations to date indicate no intractable stability or control issues for the heliogyro solar sail concept.
Advanced stability control of multi-machine power system by vips apparatus
Yokoyama, A. [Tokyo Univ., Tokyo (Japan). Dept. of Electrical Engineering; Sekine, Y. [Science Univ. of Tokyo, Tokyo (Japan). Dept. of Electrical Engineering
1994-12-31
New technology such as synchronized switching and power electronics will make it possible to change the configuration of transmission network, the impedances of transmission lines and the phase angles of voltage in the future power systems. This paper presents a comprehensive power system damping control by power electronics based variable impedance apparatus such as variable series capacitor and high speed phase shifter and also shows a novel switching-over control of transmission lines by synchronized switching for the first awing stability and damping enhancement. The control scheme discussed in this paper is based on an energy function of multi-machine power system and its time derivative. Its effectiveness is demonstrated by digital simulations and eigenvalue analysis in multi-machine test systems. It is demonstrated that multiple switching of transmission lines improves damping in the post-fault conditions. (author) 13 refs., 24 figs., 5 tabs.
Srokowski, A. J.
1978-01-01
The problem of obtaining accurate estimates of suction requirements on swept laminar flow control wings was discussed. A fast accurate computer code developed to predict suction requirements by integrating disturbance amplification rates was described. Assumptions and approximations used in the present computer code are examined in light of flow conditions on the swept wing which may limit their validity.
Resnick, Cory M; Rottgers, Stephen Alex; Langenfeld, Christopher C; Mulliken, John B; Padwa, Bonnie L
2016-06-01
The major limitation of the rigid external devices currently used for midfacial distraction after subcranial Le Fort III osteotomies is the ductile wire that connects the midface to the device, which makes it difficult to control the vector and force during distraction. The authors describe a novel external appliance that addresses this and other problems of contemporary devices, and application of a custom cranial template that facilitates precise placement of the device to achieve the planned vector of distraction. PMID:27213737
Spacecraft stability and control
Barret, Chris
1992-01-01
The Earth's first artificial satellite, Sputnik 1, slowly tumbled in orbit. The first U.S. satellite, Explorer 1, also tumbled out of control. Today, satellite stability and control has become a higher priority. For a satellite design that is to have a life expectancy of 14 years, appropriate spacecraft flight control systems will be reviewed, stability requirements investigated, and an appropriate flight control system recommended in order to see the design process. Disturbance torques, including aerodynamic, magnetic, gravity gradient, solar, micrometeorite, debris, collision, and internal torques, will be assessed to quantify the disturbance environment so that the required compensating torques can be determined. The control torques, including passive versus active, momentum control, bias momentum, spin stabilization, dual spin, gravity gradient, magnetic, reaction wheels, control moment gyros, inertia augmentation techniques, three-axis control, and reaction control systems (RCSs), will be considered. Conditions for stability will also be considered.
MHD stability of advanced tokamak scenarios
Tokamak plasmas with a non-monotonic q-profile (current profile) and negative shear in the plasma centre have been associated with improved confinement and large pressure gradients in the region of negative shear. In JET, this regime, has been obtained with pellet injection (the PEP mode) and in DIII-D by ramping the plasma elongation. In JET, the phase of improved confinement is transient and usually ends in a collapse due to an MHD instability which leads to a redistribution of the current and a monotonic q-profile. The infernal mode, which is driven by a large pressure gradient in the region of low shear near the minimum in the q-profile, is the most likely candidate for the observed instability. To extend the transient phase to steady state, control of the shape of the current density profile is essential. The modelling of these advanced tokamak scenarios with a non-monotonic q-profile using non-inductive current drive of lower hybrid waves, fast waves, and neutral beams is discussed elsewhere. The aim is to find suitable initial states and to maintain MHD stability when the plasma β is built up. For this purpose, the robustness of the MHD stability of these configurations is studied with respect to changes in the position and in the depth of the minimum in q, and in the shape of the q and pressure profile. The classes of equilibria chosen for the analysis are based on the modelling of the current-drive schemes for advanced tokamak scenarios in JET. The toroidal ideal and resistive MHD stability code CASTOR is used for the stability calculations. (author) 7 refs., 4 figs
Image stabilization for SWIR advanced optoelectronic device
Schiopu, Paul; Manea, Adrian; Cristea, Ionica; Grosu, Neculai; Craciun, Anca-Ileana; Craciun, Alexandru; Granciu, Dana
2015-02-01
At long ranges and under low visibility conditions, Advanced Optoelectronic Device provides the signal-to-noise ratio and image quality in the Short-wave Infra-red - SWIR (wavelengths between 1,1 ÷2,5 μm), significantly better than in the near wave infrared - NWIR and visible spectral bands [1,2]. The quality of image is nearly independent of the polarization in the incoming light, but it is influenced by the relative movement between the optical system and the observer (the operators' handshake), and the movement towards the support system (land and air vehicles). All these make it difficult to detect objectives observation in real time. This paper presents some systems enhance which the ability of observation and sighting through the optical systems without the use of the stands, tripods or other means. We have to eliminate the effect of "tremors of the hands" and the vibration in order to allow the use of optical devices by operators on the moving vehicles on land, on aircraft, or on boats, and to provide additional comfort for the user to track the moving object through the optical system, without losing the control in the process of detection and tracking. The practical applications of stabilization image process, in SWIR, are the most advanced part of the optical observation systems available worldwide [3,4,5]. This application has a didactic nature, because it ensures understanding by the students about image stabilization and their participation in research.
Zhou, Jianjun
1999-01-01
This book is developed as a textbook for the course Advanced Control Engineering. The book is intended for students in mechanical engineering and its aim is to provide an understanding of modern control theory as well as methodologies and applications for state space modeling and design. For this...
Zhou, Jianjun
1999-01-01
This book is developed as a textbook for the course Advanced Control Engineering. The book is intended for students in mechanical engineering and its aim is to provide an understanding of modern control theory as well as methodologies and applications for state space modeling and design. For this...... reason, the book puts emphasis on the state-space approach. The main contents of the book includes state-space representation of dynamic systems, analysis of linear control systems, feedback control and observer design. Both continuous-time and discrete-time systems have been addressed in this book....
The CANDU 9 design is based upon the 900 MWe class Darlington station in Canada, which is among the world leading nuclear power stations for capacity factor with low operation, maintenance and administration costs. The CANDU 9 design provides an advanced control centre with enhanced operations features. The advanced AECL control centre design includes the proven functionality of existing CANDU control centres, those implementable characteristics identified by systematic design combined with a human factors analysis of operations requirements and features needed to improve station operability which are made possible by the application of current technology. The design strategy is to preserve the general main control room operations staff work area as unchanged as possible to facilitate the inclusion of past features and operational experience while incorporating operability improvements. The author will present those features of the advanced CANDU control centre which facilitates improved operability capabilities. As well, aspects of the design process utilized, application of simulation technology and conclusions regarding this design approach will be reviewed
Advanced Functional Polymers for Increasing the Stability of Organic Photovoltaics
Bundgaard, Eva; Helgesen, Martin; Carlé, Jon Eggert;
2013-01-01
nanostructure. Chemical units can be introduced that impart an increased stability. Similarly, the morphological degradation of the optimal nanostructure can be reduced. Active polymers and blends with acceptor material are used to create nanoparticle links with controlled size. Most of these advanced polymers...
Beam Stability at the Advanced Photon Source
Decker, Glenn
2005-01-01
The Advanced Photon Source has been in operation since 1996. Since that time, extensive incremental improvements to orbit stabilization systems have been made. This includes the addition of 80 channels of narrowband rf beam position monitors (bpm's), 40 channels of bending magnet photon bpm's, and most recently the inclusion of 36 insertion device photon bpm's into the orbit correction response matrix. In addition, considerable improvements have been made in the area of power supply regulation, both for the main multipole magnets and the steering corrector magnets. The present status of overall performance will be discussed, including long term pointing stability, reproducibility, and AC beam motion.
Advanced Wavefront Control Techniques
Olivier, S S; Brase, J M; Avicola, K; Thompson, C A; Kartz, M W; Winters, S; Hartley, R; Wihelmsen, J; Dowla, F V; Carrano, C J; Bauman, B J; Pennington, D M; Lande, D; Sawvel, R M; Silva, D A; Cooke, J B; Brown, C G
2001-02-21
this project, work was performed in four areas (1) advanced modeling tools for deformable mirrors (2) low-order wavefront correctors with Alvarez lenses, (3) a direct phase measuring heterdyne wavefront sensor, and (4) high-spatial-frequency wavefront control using spatial light modulators.
Transient stability and emergency control
ZHANG XueMin; MEI ShengWei; WU ShengYu
2009-01-01
Comparability of emergency control strategies with different instability modes is the key issue to de-cide which control strategy to be implemented. This paper considers that the essential factor causing instability should be used to form a unified standard to assess the effectiveness of control strategies with different instability modes. Thus a switching control stabilization principle was proposed based on elimination of the unbalanced energy between mechanical and electrical energies of generator sets. Along this way, the difficulty of seeking a Lyapunov function was circumvented. According to the prin-ciple, an emergency control algorithm framework was established to handle transient stability as-sessment, control location selection and control amount evaluation. Within the framework, this paper studied instability mode transition, then proposed an algorithm based on prediction function and a new approach to normalized stability margin stemmed from static EEAC method, which can increase com-parability of various control locations. The simulations on the New-England System verified the pro-posed emergency control method for stabilizing transient stability.
Concepts of stability and control
The first part of the paper deals with the role transfer functions play in control problems (closed loop, Nyquist stability criterion, sampled data systems and z-transforms; the ''hog cycle''; spring oscillations; Lyapunov functions; the Zubov method; positive-real functions and the Popov criterion; the circle criterion; linear time-delay systems; equations with periodic coefficients; stability of repeated processes). In the second part the author considers the control of systems which are described by partial differential equations (heat-conduction equation; wave equation; control of the heat and the wave equations; parasitic oscillations; noise in linear systems; discrete noise processes). Many examples are given and briefly discussed. (author)
Pre-stabilized Lasers for Advanced Detectors
Man, C.-Nary
Gravitational wave detectors need very stable continuous wave laser sources able to delivering high power beams. Realization of those lasers is a special R&D calling on very low noise controls on very reliable laser sources. After a brief introduction on the laser principles, we review the current laser sources for gravitational wave interferometric detectors, shortly describing the technologies of both solid-state and fiber lasers and amplifiers. A final section addresses the issue of laser pre-stabilization.
Fritzsche, C; Deunow, H.-P.
2008-01-01
In the chapter we discussed a control approach for torque control of gasoline engines. Because of several actuating variables and control requirements the process to be controlled is multivariable. The actuating variables are usually bounded and the effects on the engine torque are nonlinear. Hence direct use of the actuator variables for torque control generally produces plenty of problems. The two layer approach described in the chapter allows the application of standard control methods. Th...
Finite-time stability and control
Amato, Francesco; Ariola, Marco; Cosentino, Carlo; De Tommasi, Gianmaria
2014-01-01
Finite-time stability (FTS) is a more practical concept than classical Lyapunov stability, useful for checking whether the state trajectories of a system remain within pre-specified bounds over a finite time interval. In a linear systems framework, FTS problems can be cast as convex optimization problems and solved by the use of effective off-the-shelf computational tools such as LMI solvers. Finite-time Stability and Control exploits this benefit to present the practical applications of FTS and finite-time control-theoretical results to various engineering fields. The text is divided into two parts: · linear systems; and · hybrid systems. The building of practical motivating examples helps the reader to understand the methods presented. Finite-time Stability and Control is addressed to academic researchers and to engineers working in the field of robust process control. Instructors teaching graduate courses in advanced control will also find parts of this book useful for the...
Advanced Control of Turbofan Engines
Richter, Hanz
2012-01-01
Advanced Control of Turbofan Engines describes the operational performance requirements of turbofan (commercial)engines from a controls systems perspective, covering industry-standard methods and research-edge advances. This book allows the reader to design controllers and produce realistic simulations using public-domain software like CMAPSS: Commercial Modular Aero-Propulsion System Simulation, whose versions are released to the public by NASA. The scope of the book is centered on the design of thrust controllers for both steady flight and transient maneuvers. Classical control theory is not dwelled on, but instead an introduction to general undergraduate control techniques is provided. This book also: Develops a thorough understanding of the challenges associated with engine operability from a control systems perspective, describing performance demands and operational constraints into the framework and language of modern control theory Presents solid theoretical support for classical and advanced engine co...
Kazmierkowski, M.P. [Institute of Control and Industrial Electronics, Warsaw University of Technology, Warszawa (Poland)
1997-12-31
In this paper a review of control methods for high performance PWM inverter-fed induction motor drives is presented. Starting from the description of an induction motor by the help of the space vectors, three basic control strategic are discussed. As first, the most popular Field Oriented Control (FOC) is described. Secondly, the Direct Torque and Flux vector Control (DTFC) method, which - in contrast to FOC - depart from idea of coordinate transformation and analogy with DC motor, is briefly characterized. The last group is based on Feedback Linearization Control (FLC) and can be easy combined with sliding mode control. The simulation and experimental oscillograms that illustrate the performance of the discussed control strategies are shown. (orig.) 35 refs.
Khaled M. Saadeldin Eldalil
2009-01-01
Full Text Available The load acting on the actively controlled cylindrical shell under a transient pressure pulse propelling a moving mass (gun case has been experimentally studied. The concept of using piezoelectric stack and stiffener combination is utilized for damping the tube wall radial and circumferential deforming vibrations, in the correct meeting location timing of the moving mass. The experiment was carried out by using the same stiffened shell tube of the experimental 14 mm gun tube facility which is used in part 1. Using single and double stacks is tried at two pressure levels of low-speed modes, which have response frequencies adapted with the used piezoelectric stacks characteristics. The maximum active damping ratio is occurred at high-pressure level. The radial circumferential strains are measured by using high-frequency strain gage system in phase with laser beam detection system similar to which used in part 1. Time resolved strain measurements of the wall response were obtained, and both precursor and transverse hoop strains have been resolved. A complete comparison had been made between the effect of active controlled and stepped structure cases, which indicate a significant attenuation ratio especially at higher operating pressures.
INTEGRATED PLASMA CONTROL FOR ADVANCED TOKAMAKS
OAK-B135 Advanced tokamaks (AT) are distinguished from conventional tokamaks by their high degree of shaping, achievement of profiles optimized for high confinement and stability characteristics, and active stabilization of MHD instabilities to attain high values of normalized beta and confinement. These high performance fusion devices thus require accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating, as well as simultaneous and well-coordinated MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Satisfying the simultaneous demands on control accuracy, reliability, and performance for all of these subsystems requires a high degree of integration in both design and operation of the plasma control system in an advanced tokamak. The present work describes the approach, benefits, and progress made in integrated plasma control with application examples drawn from the DIII-D tokamak. The approach includes construction of plasma and system response models, validation of models against operating experiments, design of integrated controllers which operate in concert with one another as well as with supervisory modules, simulation of control action against off-line and actual machine control platforms, and iteration of the design-test loop to optimize performance
INTEGRATED PLASMA CONTROL FOR ADVANCED TOKAMAKS
HUMPHREYS,D.A; FERRON,J.R; JOHNSON,R.D; LEUER,J.A; PENAFLOR,B.G; WALKER,M.L; WELANDER,A.S; KHAYRUTDINOV,R.R; DOKOUKA,V; EDGELL,D.H; FRANSSON,C.M
2003-10-01
OAK-B135 Advanced tokamaks (AT) are distinguished from conventional tokamaks by their high degree of shaping, achievement of profiles optimized for high confinement and stability characteristics, and active stabilization of MHD instabilities to attain high values of normalized beta and confinement. These high performance fusion devices thus require accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating, as well as simultaneous and well-coordinated MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Satisfying the simultaneous demands on control accuracy, reliability, and performance for all of these subsystems requires a high degree of integration in both design and operation of the plasma control system in an advanced tokamak. The present work describes the approach, benefits, and progress made in integrated plasma control with application examples drawn from the DIII-D tokamak. The approach includes construction of plasma and system response models, validation of models against operating experiments, design of integrated controllers which operate in concert with one another as well as with supervisory modules, simulation of control action against off-line and actual machine control platforms, and iteration of the design-test loop to optimize performance.
ADVANCED SULFUR CONTROL CONCEPTS
Apostolos A. Nikolopoulos; Santosh K. Gangwal; William J. McMichael; Jeffrey W. Portzer
2003-01-01
Conventional sulfur removal in integrated gasification combined cycle (IGCC) power plants involves numerous steps: COS (carbonyl sulfide) hydrolysis, amine scrubbing/regeneration, Claus process, and tail-gas treatment. Advanced sulfur removal in IGCC systems involves typically the use of zinc oxide-based sorbents. The sulfides sorbent is regenerated using dilute air to produce a dilute SO{sub 2} (sulfur dioxide) tail gas. Under previous contracts the highly effective first generation Direct Sulfur Recovery Process (DSRP) for catalytic reduction of this SO{sub 2} tail gas to elemental sulfur was developed. This process is currently undergoing field-testing. In this project, advanced concepts were evaluated to reduce the number of unit operations in sulfur removal and recovery. Substantial effort was directed towards developing sorbents that could be directly regenerated to elemental sulfur in an Advanced Hot Gas Process (AHGP). Development of this process has been described in detail in Appendices A-F. RTI began the development of the Single-step Sulfur Recovery Process (SSRP) to eliminate the use of sorbents and multiple reactors in sulfur removal and recovery. This process showed promising preliminary results and thus further process development of AHGP was abandoned in favor of SSRP. The SSRP is a direct Claus process that consists of injecting SO{sub 2} directly into the quenched coal gas from a coal gasifier, and reacting the H{sub 2}S-SO{sub 2} mixture over a selective catalyst to both remove and recover sulfur in a single step. The process is conducted at gasifier pressure and 125 to 160 C. The proposed commercial embodiment of the SSRP involves a liquid phase of molten sulfur with dispersed catalyst in a slurry bubble-column reactor (SBCR).
Advanced access control system
A prototype voice verification system has been installed which provides the required positive identification at the main site access control point. This system compares an individual's file voice print with a sample voice print obtained from the individual when an attempt is made to enter the site. The voice system transmits the individual's identify to a central processor. The system installed at the Barnwell Nuclear Fuel Plant is described
Advanced Control Architectures for Intelligent MicroGrids, Part I
Guerrero, Josep M.; Chandorkar, Mukul; Lee, Tzung-Lin; Loh, Poh Chiang
2013-01-01
This paper presents a review of advanced control techniques for microgrids. The paper covers decentralized, distributed, and hierarchical control of grid connected and islanded microgrids. At first, decentralized control techniques for microgrids are reviewed. Then, the recent developments in the...... stability analysis of decentralized controlled microgrids are discussed. Finally, hierarchical control for microgrids that mimic the behavior of the mains grid is reviewed....
Advances in automotive control 2001
Kiencke, U.; Gissinger, G.L. (eds.)
2001-07-01
The aim of the 3rd IFAC Workshop 'Advances in Automotive Control', held in Karlsruhe, Germany on 28-30 March 2001, was to discuss the latest advances in relation to motor vehicles. The increase in road traffic in the 20th century was a major problem, and one of the challenges of the 21st century will be to improve driving safety and comfort. The proceedings covers: driveline control; driveline modelling; vehicle dynamics; electronic architecture; intelligent components; engine control; diagnostics; subsystems; engine modelling; and modelling of combustion and turbo-charging. 28 of the papers are abstracted here.
Advanced access control system
A prototype voice verification system has been installed which provides the required positive identification at the main site access control point. This system compares an individual's file voice print with a sample voice print obtained from the individual when an attempt is made to enter the site. The voice system transmits the individual's identity to a central processor. The central processor associates that individual's authorization file with a card-key obtained at the access point. The system generates a record of personnel movement, provides a personnel inventory on a real-time basis, and it can retrieve a record of all prior events. The system installed at the Barnwell Nuclear Fuel Plant is described
Arms Control and Strategic Stability
Hu; Yumin
2014-01-01
This essay intends to offer a comment on concepts, trends and attitudes concerning arms control and strategic stability with reference to the current international security situation. It also offers observations from two different perspectives about strategic stability: one proceeds from the concept of universal security and aims to prevent conflicts and instability from disrupting regional and international security environment on which nation states depend so much for their peaceful development; the other starts from maintaining the global leadership by a super power and aiming to contain any challenge that sways or is likely to sway its dominating status. If China and the United States commit themselves to the undertaking of a new type of major powers relationship that stresses win-win cooperation, they will be able to contribute greatly to a stable international security architecture that is good for world peaceful development.
Fundamental limits on beam stability at the Advanced Photon Source
Orbit correction is now routinely performed at the few-micron level in the Advanced Photon Source (APS) storage ring. Three diagnostics are presently in use to measure and control both AC and DC orbit motions: broad-band turn-by-turn rf beam position monitors (BPMs), narrow-band switched heterodyne receivers, and photoemission-style x-ray beam position monitors. Each type of diagnostic has its own set of systematic error effects that place limits on the ultimate pointing stability of x-ray beams supplied to users at the APS. Limiting sources of beam motion at present are magnet power supply noise, girder vibration, and thermal timescale vacuum chamber and girder motion. This paper will investigate the present limitations on orbit correction, and will delve into the upgrades necessary to achieve true sub-micron beam stability
Attitude control and stabilization technology discipline
Sunkel, John W.
1990-01-01
Viewgraphs on attitude control and stabilization technology discipline for the Space Station Freedom are presented. Topics covered include: attitude control technologies for multi-user accommodation; flexible dynamics and control; computational control techniques; and automatic proximity operations.
Closed-loop transient stability emergency control
Ernst, Damien; Pavella, Mania
2000-01-01
The question of transient stability control is revisited, various types of controls are identified, and a general approach to closed-loop emergency control is proposed. The focus is on feasibility aspects, general salient features and illustration of stabilization capabilities of an emergency control scheme relying on generation shedding.
Control definition study for advanced vehicles
Lapins, M.; Martorella, R. P.; Klein, R. W.; Meyer, R. C.; Sturm, M. J.
1983-01-01
The low speed, high angle of attack flight mechanics of an advanced, canard-configured, supersonic tactical aircraft designed with moderate longitudinal relaxed static stability (Static Margin, SM = 16% C sub W at M = 0.4) was investigated. Control laws were developed for the longitudinal axis (""G'' or maneuver and angle of attack command systems) and for the lateral/directional axes. The performance of these control laws was examined in engineering simulation. A canard deflection/rate requirement study was performed as part of the ""G'' command law evaluation at low angles of attack. Simulated coupled maneuvers revealed the need for command limiters in all three aircraft axes to prevent departure from controlled flight. When modified with command/maneuver limiters, the control laws were shown to be adequate to prevent aircraft departure during aggressive air combat maneuvering.
Stability of infernal and ballooning modes in advanced tokamak scenarios
Holties, H. A.; Huysmans, G. T. A.; Goedbloed, J. P.; Kerner, W.; Parail, V.V.; Soldner, F. X.
1996-01-01
A numerical parameter study has been performed in order to find MHD stable operating regimes for advanced tokamak experiments In this study we have concentrated on internal modes. Ballooning stability and stability with respect to infernal modes are considered. The calculations confirm that pressure
Advances in vaccine stability monitoring technology.
Zweig, Stephen E
2006-08-14
Electronic time-temperature indicator (eTTI) monitors can be programmed to exactly follow the stability characteristics of vaccines with a high degree of realism. The monitors have a visual output, enabling vaccine status to be assessed at a glance, and can also output more detailed statistical data. When packaged with vaccine vials in groups of about 10 vials per box, the eTTI can remain with a vaccine throughout most of the vaccine's lifetime. The monitors can detect essentially all cold-chain breaks, and can detect issues, such as inadvertent freezing, that are presently not detected by other vaccine stability monitors such as Vaccine Vial Monitors (VVM). PMID:16759766
Advanced gray rod control assembly
Drudy, Keith J; Carlson, William R; Conner, Michael E; Goldenfield, Mark; Hone, Michael J; Long, Jr., Carroll J; Parkinson, Jerod; Pomirleanu, Radu O
2013-09-17
An advanced gray rod control assembly (GRCA) for a nuclear reactor. The GRCA provides controlled insertion of gray rod assemblies into the reactor, thereby controlling the rate of power produced by the reactor and providing reactivity control at full power. Each gray rod assembly includes an elongated tubular member, a primary neutron-absorber disposed within the tubular member said neutron-absorber comprising an absorber material, preferably tungsten, having a 2200 m/s neutron absorption microscopic capture cross-section of from 10 to 30 barns. An internal support tube can be positioned between the primary absorber and the tubular member as a secondary absorber to enhance neutron absorption, absorber depletion, assembly weight, and assembly heat transfer characteristics.
Electric machine differential for vehicle traction control and stability control
Kuruppu, Sandun Shivantha
Evolving requirements in energy efficiency and tightening regulations for reliable electric drivetrains drive the advancement of the hybrid electric (HEV) and full electric vehicle (EV) technology. Different configurations of EV and HEV architectures are evaluated for their performance. The future technology is trending towards utilizing distinctive properties in electric machines to not only to improve efficiency but also to realize advanced road adhesion controls and vehicle stability controls. Electric machine differential (EMD) is such a concept under current investigation for applications in the near future. Reliability of a power train is critical. Therefore, sophisticated fault detection schemes are essential in guaranteeing reliable operation of a complex system such as an EMD. The research presented here emphasize on implementation of a 4kW electric machine differential, a novel single open phase fault diagnostic scheme, an implementation of a real time slip optimization algorithm and an electric machine differential based yaw stability improvement study. The proposed d-q current signature based SPO fault diagnostic algorithm detects the fault within one electrical cycle. The EMD based extremum seeking slip optimization algorithm reduces stopping distance by 30% compared to hydraulic braking based ABS.
Advanced Control of Electrochromic Windows
Scartezzini, Jean-Louis; Zarkadis, Nikos; Morel, Nicolas
2013-01-01
In our research we use the technology of electrochromic (EC) glazing to maximize the use of daylight and minimize the energy consumption in buildings while preserving visual and thermal comfort of the users. We propose an advanced automatic control of EC windows coupled with an anidolic daylighting system (ADS), blinds and dimmable fluorescent lights. EC windows with a visible transmittance range (Tv) of 0.15 – 0.50 were installed on the southern façade of an office room of the LESO experimen...
Advanced Emissions Control Development Program: Mercury Control
McDermott Technology, Inc. (a subsidiary of Babcock ampersand Wilcox) is conducting the Advanced Emissions Control Development Project (AECDP) which is aimed at the development of practical, cost-effective strategies for reducing the emissions of hazardous air pollutants (HAPS) from coal-fired electric utility plants. The need for such controls may arise as the US Environmental Protection Agency (EPA) proceeds with implementation of requirements set forth in the Clean Air Act Amendments (CAAA's) of 1990. Promulgation of air toxics emissions regulations for electric utility plants could dramatically impact utilities burning coal, their industrial and residential customers, and the coal industry. AECDP project work will supply the information needed by utilities to respond to potential HAPs regulations in a timely, cost-effective, enviromnentally-sound manner which supports the continued use of the Nation's abundant reserves of coal, such as those in the State of Ohio. The development work is being carried out using the 10 MW Clean Environment Development Facility wherein air toxics emissions control strategies can be developed under controlled conditions. The specific objectives of the project are to (1) measure and understand production and partitioning of air toxics species for a variety of coals, (2) optimize the air toxics removal performance of conventional flue gas cleanup systems, (3) develop advanced air toxics emissions control concepts, (4) develop and validate air toxics emissions measurement and monitoring techniques, and (5) establish a comprehensive, self-consistent air toxics data library. This project is supported by the Department of Energy, the Ohio Coal Development Office within the Ohio Department of Development and Babcock ampersand Wilcox. A comprehensive assessment of HAP emissions from coal-fired electric utility boilers sponsored by the Department of Energy and the Electric Power Research Institute concluded that with the exception of
U31: Vehicle Stability and Dynamics: Electronic Stability Control
Petrolino, Joseph [National Transportation Research Center (NTRC); Spezia, Tony [National Transportation Research Center (NTRC); Arant, Michael [Clemson University; Delorenzis, Damon [Clemson University; LaClair, Tim J [ORNL; Lim, Alvin [Auburn University, Auburn, Alabama; Pape, Doug [Battelle
2011-01-01
A team led by NTRCI is working to improve the roll and yaw stability of heavy duty combination trucks through developing stability algorithms, assembling demonstration hardware, and investigating robust wireless communication. Modern electronic stability control (ESC) products automatically slow a vehicle rounding a corner too quickly or apply individual brakes when necessary to improve the steering characteristics of a vehicle. Air brake systems in North America provide no electronic communication between a tractor and semitrailer, limiting the degree to which control systems can be optimized. Prior research has demonstrated stability improvements where dynamic measurements and control commands are communicated between units of a vehicle. Three related activities were undertaken: (1) Develop an algorithm for the optimum yaw and roll control of a combination vehicle. Vehicle state parameters needed to control the vehicle and the proper brake response were determined. An integrated stability control for the tractor and semitrailer requires communication between the two units. Dynamic models were used to assess the algorithm. (2) Implement the ESC algorithm in the laboratory. Hardware components suitable for the harsh environment for measurement, sensor-to-controller communication, and semitrailer-to-tractor communication and brake actuation were specified and assembled as a working system. The goal was to collect the needed vehicle state information, transmit the information to the ESC system, and then actuate the brakes in response to controller commands. (3) Develop a wireless network with the data rate and reliability necessary to communicate dynamic signals for a vehicle stability control system. Adaptive connectivity-aware, multi-hop routing was selected because it can perform in the harsh environment where packet collisions and fading often will exist. The protocol is to give high priority to urgent messages.
Advanced Emissions Control Development Program
A.P.Evans; K.E. Redinger; M.J. Holmes
1998-04-01
The objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. Ideally, the project aim is to effectively control air toxic emissions through the use of conventional flue gas cleanup equipment such as electrostatic precipitators (ESPS), fabric filters (baghouse), and wet flue gas desulfurization. Development work to date has concentrated on the capture of mercury, other trace metals, fine particulate and hydrogen chloride. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on the evaluation of mercury and several other air toxics emissions. The AECDP is jointly funded by the United States Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (oCDO), and Babcock& Wilcox-a McDermott company (B&W).
MATLAB Stability and Control Toolbox Trim and Static Stability Module
Kenny, Sean P.; Crespo, Luis
2012-01-01
MATLAB Stability and Control Toolbox (MASCOT) utilizes geometric, aerodynamic, and inertial inputs to calculate air vehicle stability in a variety of critical flight conditions. The code is based on fundamental, non-linear equations of motion and is able to translate results into a qualitative, graphical scale useful to the non-expert. MASCOT was created to provide the conceptual aircraft designer accurate predictions of air vehicle stability and control characteristics. The code takes as input mass property data in the form of an inertia tensor, aerodynamic loading data, and propulsion (i.e. thrust) loading data. Using fundamental nonlinear equations of motion, MASCOT then calculates vehicle trim and static stability data for the desired flight condition(s). Available flight conditions include six horizontal and six landing rotation conditions with varying options for engine out, crosswind, and sideslip, plus three take-off rotation conditions. Results are displayed through a unique graphical interface developed to provide the non-stability and control expert conceptual design engineer a qualitative scale indicating whether the vehicle has acceptable, marginal, or unacceptable static stability characteristics. If desired, the user can also examine the detailed, quantitative results.
Hybrid Intelligent Control for Submarine Stabilization
Minghui Wang
2013-05-01
Full Text Available While sailing near the sea surface, submarines will often undergo rolling motion caused by wave disturbance. Fierce rolling motion seriously affects their normal operation and even threatens their security. We propose a new control method for roll stabilization. This paper studies hybrid intelligent control combining a fuzzy control, a neural network and extension control technology. Every control strategy can achieve the ideal control effect within the scope of its effective control. The neuro‐fuzzy control strategy is used to improve the robustness of the controller. The speed control strategy and the course control strategy are conducted to extend the control range. The paper also proposes the design of the controller and carries out the simulation experiment in different sea conditions. The simulation results show that the control method proposed can indeed effectively improve the control performance of submarine stabilization.
Matlab Stability and Control Toolbox: Trim and Static Stability Module
Crespo, Luis G.; Kenny, Sean P.
2006-01-01
This paper presents the technical background of the Trim and Static module of the Matlab Stability and Control Toolbox. This module performs a low-fidelity stability and control assessment of an aircraft model for a set of flight critical conditions. This is attained by determining if the control authority available for trim is sufficient and if the static stability characteristics are adequate. These conditions can be selected from a prescribed set or can be specified to meet particular requirements. The prescribed set of conditions includes horizontal flight, take-off rotation, landing flare, steady roll, steady turn and pull-up/ push-over flight, for which several operating conditions can be specified. A mathematical model was developed allowing for six-dimensional trim, adjustable inertial properties, asymmetric vehicle layouts, arbitrary number of engines, multi-axial thrust vectoring, engine(s)-out conditions, crosswind and gyroscopic effects.
Power system stability modelling, analysis and control
Sallam, Abdelhay A
2015-01-01
This book provides a comprehensive treatment of the subject from both a physical and mathematical perspective and covers a range of topics including modelling, computation of load flow in the transmission grid, stability analysis under both steady-state and disturbed conditions, and appropriate controls to enhance stability.
Can electronic stability control replace studded tyres?
Elvik, Rune
2015-01-01
Highlights • Electronic stability control can substitute studded tyres. • This makes it easier to discourage the use of studded tyres. • A certain level of use of studded tyres makes roads less slippery.......Highlights • Electronic stability control can substitute studded tyres. • This makes it easier to discourage the use of studded tyres. • A certain level of use of studded tyres makes roads less slippery....
Preventive and emergency transient stability control
Ernst, Damien; Ruiz-Vega, Daniel; Pavella, Mania
2000-01-01
A unified approach to transient stability closed-loop control is presented. It relies on the general transient stability method called SIME, from which the Preventive and the Emergency SIMEs are derived. The Preventive SIME uses time-domain simulations of plausible contingencies prior to their occurrence, for the online power system monitoring from the control room. The Emergency SIME, on the other hand, uses real-time measurements, acquired on the system power plants after the actual occurre...
Stability and Control of Functional Differential Equations
Peet, M M
2006-01-01
This thesis addresses the question of stability of systems defined by differential equations which contain nonlinearity and delay. In particular, we analyze the stability of a well-known delayed nonlinear implementation of a certain Internet congestion control protocol. We also describe a generalized methodology for proving stability of time-delay systems through the use of semidefinite programming. In Chapters 4 and 5, we consider an Internet congestion control protocol based on the decentralized gradient projection algorithm. For a certain class of utility function, this algorithm was shown to be globally convergent for some sufficiently small value of a gain parameter. Later work gave an explicit bound on this gain for a linearized version of the system. This thesis proves that this bound also implies stability of the original system. In Chapter 7, we describe a general methodology for proving stability of linear time-delay systems by computing solutions to an operator-theoretic version of the Lyapunov ine...
OPTIMAL CONTROL FOR ELECTRIC VEHICLE STABILIZATION
MARIAN GAICEANU
2016-01-01
Full Text Available This main objective of the paper is to stabilize an electric vehicle in optimal manner to a step lane change maneuver. To define the mathematical model of the vehicle, the rigid body moving on a plane is taken into account. An optimal lane keeping controller delivers the adequate angles in order to stabilize the vehicle’s trajectory in an optimal way. Two degree of freedom linear bicycle model is adopted as vehicle model, consisting of lateral and yaw motion equations. The proposed control maintains the lateral stability by taking the feedback information from the vehicle transducers. In this way only the lateral vehicle’s dynamics are enough to considerate. Based on the obtained linear mathematical model the quadratic optimal control is designed in order to maintain the lateral stability of the electric vehicle. The numerical simulation results demonstrate the feasibility of the proposed solution.
Recent Advances in Space-Variant Deblurring and Image Stabilization
Šorel, Michal; Šroubek, Filip; Flusser, Jan
Dordrecht, The Netherlands: Springer Science + Business Media B.V, 2009 - (Byrnes, J.), s. 259-272. (NATO Science for Peace and Security Series. B: Physics and Biophysics). ISBN 978-1-4020-8922-0 R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/1593 Institutional research plan: CEZ:AV0Z10750506 Keywords : camera shake * image stabilization * space-variant restoration * blind deconvolution Subject RIV: JD - Computer Applications, Robotics http://library.utia.cas.cz/separaty/2008/ZOI/sorel-recent advances in space-variant deblurring and image stabilization.pdf
CISM International Advanced School on Stability Problems of Steel Structures
Skaloud, M
1992-01-01
This volume strives to give complete information about the main aspect of the stability behaviour of steel structures and their members. In following this objective, the volume presents a complete scientific background (profiting from the fact that the authors of the individual parts of the publication have personally been very active in the corresponding field of research for an extended period of time now), but also establishes recommendations, procedures and formulae for practical design. The significance of the volume may be seen in its challenging current concepts of stability analysis, encouraging progress in the field and thereby establishing an advanced basis for more reliable and economical design.
Graphical user interface for design stabilizing controllers
Urban, Petr; Šebek, M.
Praha : VŠCHT, 2003, s. 594-599. ISBN 80-7080-526-9. [MATLAB 2003 /11./. Praha (CZ), 25.11.2003] R&D Projects: GA ČR GA102/02/0709 Institutional research plan: CEZ:AV0Z1075907 Keywords : interface * stabilizing controllers * Hermite matrix Subject RIV: BC - Control Systems Theory
Solidification process control for advanced superalloys
Gray, H. R.; Dreshfield, R. L.
1982-01-01
The importance of understanding and controlling the basic solidification process in high temperature alloy technology as applied to gas turbine engine production is discussed. Resultant tailoring of the superalloy macro- and microstructure offers significant potential for continued advances in superalloy use temperatures in turbine engines. Atomized superalloy powders, rapidly solidified superalloys, microstructural control, and advanced superalloys are discussed.
Advanced Control Schemes for High-Bandwidth Multiphase Voltage Regulators
Liu, Pei-Hsin
2015-01-01
Advances in transistor-integration technology and multi-core technology of the latest microprocessors have driven transient requirements to become more and more stringent. Rather than relying on the bulky output capacitors as energy-storage devices, increasing the control bandwidth (BW) of the multiphase voltage regulator (VR) is a more cost-effective and space-saving approach. However, it is found that the stability margin of current-mode control in high-BW design is very sensitive to operat...
1982-01-01
The Current and Advanced Technology ACT control system definition tasks of the Integrated Application of Active Controls (IAAC) Technology project within the Energy Efficient Transport Program are summarized. The systems mechanize six active control functions: (1) pitch augmented stability; (2) angle of attack limiting; (3) lateral/directional augmented stability; (4) gust load alleviation; (5) maneuver load control; and (6) flutter mode control. The redundant digital control systems meet all function requirements with required reliability and declining weight and cost as advanced technology is introduced.
Nonlinear stability and control of gliding vehicles
Bhatta, Pradeep
In this thesis we use nonlinear systems analysis to study dynamics and design control solutions for vehicles subject to hydrodynamic or aerodynamic forcing. Application of energy-based methods for such vehicles is challenging due to the presence of energy-conserving lift and side forces. We study how the lift force determines the geometric structure of vehicle dynamics. A Hamiltonian formulation of the integrable phugoid-mode equations provides a Lyapunov function candidate, which is used throughout the thesis for deriving equilibrium stability results and designing stabilizing control laws. A strong motivation for our work is the emergence of underwater gliders as an important observation platform for oceanography. Underwater gliders rely on buoyancy regulation and internal mass redistribution for motion control. These vehicles are attractive because they are designed to operate autonomously and continuously for several weeks. The results presented in this thesis contribute toward the development of systematic control design procedures for extending the range of provably stable maneuvers of the underwater glider. As the first major contribution we derive conditions for nonlinear stability of longitudinal steady gliding motions using singular perturbation theory. Stability is proved using a composite Lyapunov function, composed of individual Lyapunov functions that prove stability of rotational and translational subsystem equilibria. We use the composite Lyapunov function to design control laws for stabilizing desired relative equilibria in different actuation configurations for the underwater glider. We propose an approximate trajectory tracking method for an aircraft model. Our method uses exponential stability results of controllable steady gliding motions, derived by interpreting the aircraft dynamics as an interconnected system of rotational and translational subsystems. We prove bounded position error for tracking prescribed, straight-line trajectories, and
Advanced Control Test Operation (ACTO) facility
The Advanced Control Test Operation (ACTO) project, sponsored by the US Department of Energy (DOE), is being developed to enable the latest modern technology, automation, and advanced control methods to be incorporated into nuclear power plants. The facility is proposed as a national multi-user center for advanced control development and testing to be completed in 1991. The facility will support a wide variety of reactor concepts, and will be used by researchers from Oak Ridge National Laboratory (ORNL), plus scientists and engineers from industry, other national laboratories, universities, and utilities. ACTO will also include telecommunication facilities for remote users
Stabilizing the Richardson Algorithm by Controlling Chaos
He, Song
1996-01-01
By viewing the operations of the Richardson purification algorithm as a discrete time dynamical process, we propose a method to overcome the instability of the algorithm by controlling chaos. We present theoretical analysis and numerical results on the behavior and performance of the stabilized algorithm.
Advanced Coordinating Control System for Power Plant
WU Peng; WEI Shuangying
2006-01-01
The coordinating control system is popular used in power plant. This paper describes the advanced coordinating control by control methods and optimal operation, introduces their principals and features by using the examples of power plant operation. It is wealthy for automation application in optimal power plant operation.
MASCOT - MATLAB Stability and Control Toolbox
Kenny, Sean; Crespo, Luis
2011-01-01
MASCOT software was created to provide the conceptual aircraft designer accurate predictions of air vehicle stability and control characteristics. The code takes as input mass property data in the form of an inertia tensor, aerodynamic loading data, and propulsion (i.e. thrust) loading data. Using fundamental non-linear equations of motion, MASCOT then calculates vehicle trim and static stability data for any desired flight condition. Common predefined flight conditions are included. The predefined flight conditions include six horizontal and six landing rotation conditions with varying options for engine out, crosswind and sideslip, plus three takeoff rotation conditions. Results are displayed through a unique graphical interface developed to provide stability and control information to the conceptual design engineers using a qualitative scale indicating whether the vehicle has acceptable, marginal, or unacceptable static stability characteristics. This software allows the user to prescribe the vehicle s CG location, mass, and inertia tensor so that any loading configuration between empty weight and maximum take-off weight can be analyzed. The required geometric and aerodynamic data as well as mass and inertia properties may be entered directly, passed through data files, or come from external programs such as Vehicle Sketch Pad (VSP). The current version of MASCOT has been tested with VSP used to compute the required data, which is then passed directly into the program. In VSP, the vehicle geometry is created and manipulated. The aerodynamic coefficients, stability and control derivatives, are calculated using VorLax, which is now available directly within VSP. MASCOT has been written exclusively using the technical computing language MATLAB . This innovation is able to bridge the gap between low-fidelity conceptual design and higher-fidelity stability and control analysis. This new tool enables the conceptual design engineer to include detailed static stability
Dynamics, stability, and control of maglev systems
Cai, Y.; Chen, S.S.; Rote, D.M.; Coffey, H.T.
1993-01-01
The dynamic response of maglev systems is important in several respects: Safety and ride quality, guideway design, and system costs. The dynamic response of vehicles is the key element in the determination of ride quality, and vehicle stability is one of the important elements relative to safety. To design a proper guideway that provides acceptable ride quality in the stable region, the vehicle dynamics must be understood. The trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. This paper is a summary of our previous work on dynamics, stability and control of maglev systems. First of all, the importance of dynamics of vehicle/guideway of maglev systems is discussed. Emphasis is placed on the modeling vehicle/guideway interactions of maglev systems with a multicar, or multiload vehicle traversing on a single or double-span flexible guideway. Coupled effects of vehicle/guideway interactions in wide range of vehicle speeds with various vehicle and guideway parameters for maglev systems are investigated. Secondly, the alternative control designs of maglev vehicle suspension systems are investigated in this study to achieve safe, stable operation and acceptable ride comfort requires some form of vehicle motion control. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. Finally, this paper discusses the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.
Dynamics, stability, and control of maglev systems
Cai, Y.; Chen, S.S.; Rote, D.M.; Coffey, H.T.
1993-06-01
The dynamic response of maglev systems is important in several respects: Safety and ride quality, guideway design, and system costs. The dynamic response of vehicles is the key element in the determination of ride quality, and vehicle stability is one of the important elements relative to safety. To design a proper guideway that provides acceptable ride quality in the stable region, the vehicle dynamics must be understood. The trade-off between guideway smoothness and the levitation and control systems must be considered if maglev systems are to be economically feasible. This paper is a summary of our previous work on dynamics, stability and control of maglev systems. First of all, the importance of dynamics of vehicle/guideway of maglev systems is discussed. Emphasis is placed on the modeling vehicle/guideway interactions of maglev systems with a multicar, or multiload vehicle traversing on a single or double-span flexible guideway. Coupled effects of vehicle/guideway interactions in wide range of vehicle speeds with various vehicle and guideway parameters for maglev systems are investigated. Secondly, the alternative control designs of maglev vehicle suspension systems are investigated in this study to achieve safe, stable operation and acceptable ride comfort requires some form of vehicle motion control. Active and semi-active control law designs are introduced into primary and secondary suspensions of maglev vehicles. Finally, this paper discusses the stability of maglev systems based on experimental data, scoping calculations, and simple mathematical models. Divergence and flutter are obtained for coupled vibration of a three-degree-of-freedom maglev vehicle on a guideway consisting of double L-shaped aluminum segments. The theory and analysis developed in this study provides basic stability characteristics and identifies future research needs for maglev systems.
Advanced Control of Wheeled Inverted Pendulum Systems
Li, Zhijun; Fan, Liping
2013-01-01
Advanced Control of Wheeled Inverted Pendulum Systems is an orderly presentation of recent ideas for overcoming the complications inherent in the control of wheeled inverted pendulum (WIP) systems, in the presence of uncertain dynamics, nonholonomic kinematic constraints as well as underactuated configurations. The text leads the reader in a theoretical exploration of problems in kinematics，dynamics modeling, advanced control design techniques,and trajectory generation for WIPs. An important concern is how to deal with various uncertainties associated with the nominal model, WIPs being characterized by unstable balance and unmodelled dynamics and being subject to time-varying external disturbances for which accurate models are hard to come by. The book is self-contained, supplying the reader with everything from mathematical preliminaries and the basic Lagrange-Euler-based derivation of dynamics equations to various advanced motion control and force control approaches as well as trajectory generation met...
Advanced methods for BWR transient and stability analysis
Schmidt, A.; Wehle, F.; Opel, S.; Velten, R. [AREVA, AREVA NP, Erlangen (Germany)
2008-07-01
The design of advanced Boiling Water Reactor (BWR) fuel assemblies and cores is governed by the basic requirement of safe, reliable and flexible reactor operation with optimal fuel utilization. AREVA NP's comprehensive steady state and transient BWR methodology allows the designer to respond quickly and effectively to customer needs. AREVA NP uses S-RELAP5/RAMONA as the appropriate methodology for the representation of the entire plant. The 3D neutron kinetics and thermal-hydraulics code has been developed for the prediction of system, fuel and core behavior and provides additional margins for normal operation and transients. Of major importance is the extensive validation of the methodology. The validation is based on measurements at AREVA NP's test facilities, and comparison of the predictions with a great wealth of measured data gathered from BWR plants during many years of operation. Three of the main fields of interest are stability analysis, operational transients and reactivity initiated accidents (RIAs). The introduced 3D methodology for operational transients shows significant margin regarding the operational limit of critical power ratio, which has been approved by the German licensing authority. Regarding BWR stability a large number of measurements at different plants under various conditions have been performed and successfully post-calculated with RAMONA. This is the basis of reliable pre-calculations of the locations of regional and core-wide stability boundaries. (authors)
AMTD - Advanced Mirror Technology Development in Mechanical Stability
Knight, J. Brent
2015-01-01
Analytical tools and processes are being developed at NASA Marshal Space Flight Center in support of the Advanced Mirror Technology Development (AMTD) project. One facet of optical performance is mechanical stability with respect to structural dynamics. Pertinent parameters are: (1) the spacecraft structural design, (2) the mechanical disturbances on-board the spacecraft (sources of vibratory/transient motion such as reaction wheels), (3) the vibration isolation systems (invariably required to meet future science needs), and (4) the dynamic characteristics of the optical system itself. With stability requirements of future large aperture space telescopes being in the lower Pico meter regime, it is paramount that all sources of mechanical excitation be considered in both feasibility studies and detailed analyses. The primary objective of this paper is to lay out a path to perform feasibility studies of future large aperture space telescope projects which require extreme stability. To get to that end, a high level overview of a structural dynamic analysis process to assess an integrated spacecraft and optical system is included.
Advanced methods for BWR transient and stability analysis
The design of advanced Boiling Water Reactor (BWR) fuel assemblies and cores is governed by the basic requirement of safe, reliable and flexible reactor operation with optimal fuel utilization. AREVA NP's comprehensive steady state and transient BWR methodology allows the designer to respond quickly and effectively to customer needs. AREVA NP uses S-RELAP5/RAMONA as the appropriate methodology for the representation of the entire plant. The 3D neutron kinetics and thermal-hydraulics code has been developed for the prediction of system, fuel and core behavior and provides additional margins for normal operation and transients. Of major importance is the extensive validation of the methodology. The validation is based on measurements at AREVA NP's test facilities, and comparison of the predictions with a great wealth of measured data gathered from BWR plants during many years of operation. Three of the main fields of interest are stability analysis, operational transients and reactivity initiated accidents (RIAs). The introduced 3D methodology for operational transients shows significant margin regarding the operational limit of critical power ratio, which has been approved by the German licensing authority. Regarding BWR stability a large number of measurements at different plants under various conditions have been performed and successfully post-calculated with RAMONA. This is the basis of reliable pre-calculations of the locations of regional and core-wide stability boundaries. (authors)
Renewable source controls for grid stability.
Byrne, Raymond Harry; Elliott, Ryan Thomas; Neely, Jason C.; Silva Monroy, Cesar Augusto; Schoenwald, David Alan; Grant, Lisa
2012-12-01
The goal of this study was to evaluate the small signal and transient stability of the Western Electric- ity Coordinating Council (WECC) under high penetrations of renewable energy, and to identify control technologies that would improve the system performance. The WECC is the regional entity responsible for coordinating and promoting bulk electric system reliability in the Western Interconnection. Transient stability is the ability of the power system to maintain synchronism after a large disturbance while small signal stability is the ability of the power system to maintain synchronism after a small disturbance. Tran- sient stability analysis usually focuses on the relative rotor angle between synchronous machines compared to some stability margin. For this study we employed generator speed relative to system speed as a metric for assessing transient stability. In addition, we evaluated the system transient response using the system frequency nadir, which provides an assessment of the adequacy of the primary frequency control reserves. Small signal stability analysis typically identi es the eigenvalues or modes of the system in response to a disturbance. For this study we developed mode shape maps for the di erent scenarios. Prony analysis was applied to generator speed after a 1.4 GW, 0.5 second, brake insertion at various locations. Six di erent WECC base cases were analyzed, including the 2022 light spring case which meets the renewable portfolio standards. Because of the di culty in identifying the cause and e ect relationship in large power system models with di erent scenarios, several simulations were run on a 7-bus, 5-generator system to isolate the e ects of di erent con gurations. Based on the results of the study, for a large power system like the WECC, incorporating frequency droop into wind/solar systems provides a larger bene t to system transient response than replacing the lost inertia with synthetic inertia. From a small signal stability
Advances and applications in nonlinear control systems
Volos, Christos
2016-01-01
The book reports on the latest advances and applications of nonlinear control systems. It consists of 30 contributed chapters by subject experts who are specialized in the various topics addressed in this book. The special chapters have been brought out in the broad areas of nonlinear control systems such as robotics, nonlinear circuits, power systems, memristors, underwater vehicles, chemical processes, observer design, output regulation, backstepping control, sliding mode control, time-delayed control, variables structure control, robust adaptive control, fuzzy logic control, chaos, hyperchaos, jerk systems, hyperjerk systems, chaos control, chaos synchronization, etc. Special importance was given to chapters offering practical solutions, modeling and novel control methods for the recent research problems in nonlinear control systems. This book will serve as a reference book for graduate students and researchers with a basic knowledge of electrical and control systems engineering. The resulting design proce...
JPL Advanced Thermal Control Technology Roadmap - 2012
Birur, Gaj; Rodriguez, Jose I.
2012-01-01
NASA's new emphasis on human exploration program for missions beyond LEO requires development of innovative and revolutionary technologies. Thermal control requirements of future NASA science instruments and missions are very challenging and require advanced thermal control technologies. Limited resources requires organizations to cooperate and collaborate; government, industry, universities all need to work together for the successful development of these technologies.
Advanced nonlinear engine speed control systems
Vesterholm, Thomas; Hendricks, Elbert
1994-01-01
Several subsidiary control problems have turned out to be important for improving driveability and fuel consumption in modern spark ignition (SI) engine cars. Among these are idle speed control and cruise control. In this paper the idle speed and cruise control problems will be treated as one......: accurately tracking of a desired engine speed in the presence of model uncertainties and severe load disturbances. This is accomplished by using advanced nonlinear control techniques such as input/output-linearization and sliding mode control. These techniques take advantage of a nonlinear model of the...
Advances in chaos theory and intelligent control
Vaidyanathan, Sundarapandian
2016-01-01
The book reports on the latest advances in and applications of chaos theory and intelligent control. Written by eminent scientists and active researchers and using a clear, matter-of-fact style, it covers advanced theories, methods, and applications in a variety of research areas, and explains key concepts in modeling, analysis, and control of chaotic and hyperchaotic systems. Topics include fractional chaotic systems, chaos control, chaos synchronization, memristors, jerk circuits, chaotic systems with hidden attractors, mechanical and biological chaos, and circuit realization of chaotic systems. The book further covers fuzzy logic controllers, evolutionary algorithms, swarm intelligence, and petri nets among other topics. Not only does it provide the readers with chaos fundamentals and intelligent control-based algorithms; it also discusses key applications of chaos as well as multidisciplinary solutions developed via intelligent control. The book is a timely and comprehensive reference guide for graduate s...
Control of time stability of scintillation spectrometer of delayed coincidences
Paper describes a system to control time stability of a two-detector plastic scintillation spectrometer of three-dimensional coincides. A two-reference control system incorporates a light guide base delay optical line, two light diodes and a two-channel generator of nanosecond pulses. A distinguishing feature of the design system is application of one delay line to form both advance and delay time signal as to the real coincidences in the studied radioactive source. The designed system of control enables to measure periods of half-decay of nuclei excited states within 40-100 ns range ensuring control of position of coincidence curve gravity centers within 4 ps limits
Control of time stability of scintillation spectrometer of delayed coincidences
Morozov, V A
2002-01-01
Paper describes a system to control time stability of a two-detector plastic scintillation spectrometer of three-dimensional coincides. A two-reference control system incorporates a light guide base delay optical line, two light diodes and a two-channel generator of nanosecond pulses. A distinguishing feature of the design system is application of one delay line to form both advance and delay time signal as to the real coincidences in the studied radioactive source. The designed system of control enables to measure periods of half-decay of nuclei excited states within 40-100 ns range ensuring control of position of coincidence curve gravity centers within 4 ps limits
An Advanced Fuzzy Logic Based Traffic Controller
Bilal Ahmed Khan; Nai Shyan Lai
2014-01-01
Traffic light plays an important role in the urban traffic management. Therefore, it is necessary to improve the traffic controller for effective traffic management and better traffic flow leading to greener environment. In this paper, an advanced and intelligent traffic light controller is proposed, utilising the fuzzy logic technology and image processing technique. A fuzzy logic control has been implemented to provide the attribute of intelligence to the system. For real-time image acquisi...
Influence of Fatigue in Neuromuscular Control of Spinal Stability
Granata, Kevin P.; Slota, Greg P.; Wilson, Sara E.
2004-01-01
Lifting-induced fatigue may influence neuromuscular control of spinal stability. Stability is primarily controlled by muscle recruitment, active muscle stiffness, and reflex response. Fatigue has been observed to affect each of these neuromuscular parameters and may therefore affect spinal stability. A biomechanical model of spinal stability was implemented to evaluate the effects of fatigue on spinal stability. The model included a 6-degree-of-freedom representation of the spine controlled b...
Operational efficiency subpanel advanced mission control
Friedland, Peter
1990-01-01
Herein, the term mission control will be taken quite broadly to include both ground and space based operations as well as the information infrastructure necessary to support such operations. Three major technology areas related to advanced mission control are examined: (1) Intelligent Assistance for Ground-Based Mission Controllers and Space-Based Crews; (2) Autonomous Onboard Monitoring, Control and Fault Detection Isolation and Reconfiguration; and (3) Dynamic Corporate Memory Acquired, Maintained, and Utilized During the Entire Vehicle Life Cycle. The current state of the art space operations are surveyed both within NASA and externally for each of the three technology areas and major objectives are discussed from a user point of view for technology development. Ongoing NASA and other governmental programs are described. An analysis of major research issues and current holes in the program are provided. Several recommendations are presented for enhancing the technology development and insertion process to create advanced mission control environments.
An advanced control system for a next generation transport aircraft
Rising, J. J.; Davis, W. J; Grantham, W. D.
1983-01-01
The use of modern control theory to develop a high-authority stability and control system for the next generation transport aircraft is described with examples taken from work performed on an advanced pitch active control system (PACS). The PACS was configured to have short-period and phugoid modes frequency and damping characteristics within the shaded S-plane areas, column force gradients with set bounds and with constant slope, and a blended normal-acceleration/pitch rate time history response to a step command. Details of the control law, feedback loop, and modal control syntheses are explored, as are compensation for the feedback gain, the deletion of the velocity signal, and the feed-forward compensation. Scheduling of the primary and secondary gains are discussed, together with control law mechanization, flying qualities analyses, and application on the L-1011 aircraft.
COMSAC: Computational Methods for Stability and Control. Part 1
Fremaux, C. Michael (Compiler); Hall, Robert M. (Compiler)
2004-01-01
Work on stability and control included the following reports:Introductory Remarks; Introduction to Computational Methods for Stability and Control (COMSAC); Stability & Control Challenges for COMSAC: a NASA Langley Perspective; Emerging CFD Capabilities and Outlook A NASA Langley Perspective; The Role for Computational Fluid Dynamics for Stability and Control:Is it Time?; Northrop Grumman Perspective on COMSAC; Boeing Integrated Defense Systems Perspective on COMSAC; Computational Methods in Stability and Control:WPAFB Perspective; Perspective: Raytheon Aircraft Company; A Greybeard's View of the State of Aerodynamic Prediction; Computational Methods for Stability and Control: A Perspective; Boeing TacAir Stability and Control Issues for Computational Fluid Dynamics; NAVAIR S&C Issues for CFD; An S&C Perspective on CFD; Issues, Challenges & Payoffs: A Boeing User s Perspective on CFD for S&C; and Stability and Control in Computational Simulations for Conceptual and Preliminary Design: the Past, Today, and Future?
Probing Interfacial Emulsion Stability Controls using Electrorheology
Wang, Xiuyu; Brandvik, Amy; Alvarado, Vladimir
2010-11-01
The stability of water-in-oil emulsions is controlled by interfacial mechanisms that include oil film rheology of approaching drops and the strength of drop interfaces. Film drainage is mainly a function of the continuous phase rheology. Temperature is used to regulate the viscosity of the continuous phase and hence determine its effect on emulsion stability through film drainage, in contrast with interfacial strength. In this study, one crude oil is used to formulate water-in-oil emulsions. Oil-water interfacial tension is measured to gauge other interfacial changes with temperature. The critical field value, used as proxy of emulsion stability, approaches a plateau value for each crude oil- aqueous solution pair, at sufficiently high temperature (50 ^oC), which is interpreted to reflect the intrinsic drop-coating film resistance to coalescence. Interfacial tension does vary significantly with either aqueous phase composition or temperature. From comparison with previous results, we speculate that drop coating film is composed of a fraction of asphaltic compunds.
Advanced control architecture for autonomous vehicles
Maurer, Markus; Dickmanns, Ernst D.
1997-06-01
An advanced control architecture for autonomous vehicles is presented. The hierarchical architecture consists of four levels: a vehicle level, a control level, a rule-based level and a knowledge-based level. A special focus is on forms of internal representation, which have to be chosen adequately for each level. The control scheme is applied to VaMP, a Mercedes passenger car which autonomously performs missions on German freeways. VaMP perceives the environment with its sense of vision and conventional sensors. It controls its actuators for locomotion and attention focusing. Modules for perception, cognition and action are discussed.
The Advanced Photon Source main control room
The Advanced Photon Source at Argonne National Laboratory is a third-generation light source built in the 1990s. Like the machine itself, the Main Control Room (MCR) employs design concepts based on today's requirements. The discussion will center on ideas used in the design of the MCR, the comfort of personnel using the design, and safety concerns integrated into the control room layout
MERCURY CONTROL WITH ADVANCED HYBRID PARTICULATE COLLECTOR
Ye Zhuang; Stanley J. Miller
2005-05-01
This project was awarded under U.S. Department of Energy (DOE) National Energy Technology Laboratory (NETL) Program Solicitation DE-PS26-00NT40769 and specifically addressed Technical Topical Area 4-Testing Novel and Less Mature Control Technologies on Actual Flue Gas at the Pilot Scale. The project team included the Energy & Environmental Research Center (EERC) as the main contractor; W.L. Gore & Associates, Inc., as a technical and financial partner; and the Big Stone Power Plant operated by Otter Tail Power Company, host for the field-testing portion of the research. Since 1995, DOE has supported development of a new concept in particulate control called the advanced hybrid particulate collector (AHPC). The AHPC has been licensed to W.L. Gore & Associates, Inc., and has been marketed as the Advanced Hybrid{trademark} filter by Gore. The Advanced Hybrid{trademark} filter combines the best features of electrostatic precipitators (ESPs) and baghouses in a unique configuration, providing major synergism between the two collection methods, both in the particulate collection step and in the transfer of dust to the hopper. The Advanced Hybrid{trademark} filter provides ultrahigh collection efficiency, overcoming the problem of excessive fine-particle emissions with conventional ESPs, and it solves the problem of reentrainment and re-collection of dust in conventional baghouses. The Advanced Hybrid{trademark} filter also appears to have unique advantages for mercury control over baghouses or ESPs as an excellent gas--solid contactor. The objective of the project was to demonstrate 90% total mercury control in the Advanced Hybrid{trademark} filter at a lower cost than current mercury control estimates. The approach included bench-scale batch tests, larger-scale pilot testing with real flue gas on a coal-fired combustion system, and field demonstration at the 2.5-MW (9000-acfm) scale at a utility power plant to prove scale-up and demonstrate longer-term mercury control
Integration and Application of TCV Advanced Plasma Control System
Full text: A digital system for plasma control at Tokamak a Configuration Variable (TCV) was developed and integrated. The Advanced Plasma Control System (APCS) enables enhanced control of plasma properties such as shape, position, current and density, with more flexibility and better performance than the existing analogue system. APCS is a grid of 32 interconnected processing units with analogue input/output capabilities, using in-house developed data communication bus and protocol. The control cycle using the entire grid, with data sharing between all units, can go up to 25us, defined as the slow control cycle. For faster control needs such as the vertical stabilization of plasma, single hardware module with 4 processing units is used. By confining the communication to one hardware module, the time for data sharing is reduced and the control cycle can go down, defined as the fast control cycle. The APCS hardware and data sharing architecture is described in this contribution. To integrate the APCS in the existing TCV control plant, a software package that runs in the embedded system hosting the hardware modules was developed and installed. The host state-machine and the structure of the software are discussed, as well as the system performance and stability. An application that uses the APCS to enhance the plasma vertical position stabilization is under development. Past tokamaks with circular cross-section plasmas were vertically stable; however, vertically elongated cross section plasmas suffer from a vertical instability that demands the use of closed loop feedback control systems. The use of the APCS for vertical instability control is evaluated and results on a new vertical position observer are presented. (author)
Human factors challenges for advanced process control
New human-system interface technologies provide opportunities for improving operator and plant performance. However, if these technologies are not properly implemented, they may introduce new challenges to performance and safety. This paper reports the results from a survey of human factors considerations that arise in the implementation of advanced human-system interface technologies in process control and other complex systems. General trends were identified for several areas based on a review of technical literature and a combination of interviews and site visits with process control organizations. Human factors considerations are discussed for two of these areas, automation and controls
Critical Interactions in the Stability Control Region of Tropomyosin
Kirwan, J. Paul; Robert S Hodges
2010-01-01
Our laboratory has recently described a stability control region in the two-stranded α-helical coiled-coil α-tropomyosin that accounts for overall protein stability but is not required for folding. We have used a synthetic peptide approach to investigate three stability control sites within the stability control region (residues 97-118). Two of the sites, electrostatic cluster 1 (97-104, EELDRAQE) and electrostatic cluster 2 (112-118, KLEEAEK), feature sequences with unusually high charge den...
Disturbance observer based control system design for inertially stabilized platform
Wu, Chunnan; Lin, Zhe
2012-09-01
Inertially stabilized platform (ISP) is indispensable for various imaging systems to segregate the base angular movement and achieve high LOS (Line-Of-Sight) stability. The disturbance rejection ratio and command following performance are of primary concern in designing ISP control systems. In this paper, the redundant gimbals ISP system is considered and it is shown to experience complex disturbance and parameter variation during operation. To meet advanced LOS stabilization requirement, a disturbance observer based (DOB) dual-loop controller design for ISP is proposed of which the DOB is the internal-loop. Using a nominal plant model and a low-pass filter, the disturbance signal is estimated and used as a cancellation input added to the current command of torque motor. If the DOB works well, the disturbance torque and mismatch between nominal plant and actual plant will be compensated and the internal-loop will behave as nominal model parameters. On the other hand, the external-loop will be designed for nominal model parameters to meet stabilization requirements. This paper will mainly focus on the DOB design method. Since the low-pass filter of DOB determines the sensitivity and complementary sensitivity function as will be shown in this paper, designing the filter is the most important consideration. In this paper, an optimal low-pass filter design method is proposed. The method is intuitive, simple to implement and allows on-line tuning. Simulation results show the performance enhancement of our control structure in the presence of disturbance and measurement noise.
Nuplex 80+ - advanced instrumentation and control
Nuplex 80+ is an advanced control complex designed by ABB Combustion Engineering (ABB C-E) to meet the demanding human factors, reliability, and licensing requirements of nuclear power generating stations. It is characterized by distributed digital processing, fiber-optic data communications, and touch-sensitive video displays. This advanced design was originally developed for System 80+ [ABB C-E's evolutionary advanced light water reactor (ALWR)], but its utilization of sound human factors principles and modern digital technology has also resulted in the selection of Nuplex 80+ for use in the US Department of Energy's New Production Reactor Program. This paper offers an overview of Nuplex 80+ and some insight into the Design Certification licensing process and key issues of the US Nuclear Regulatory Commission (NRC) review
Controlling air toxics through advanced coal preparation
Straszheim, W.E.; Buttermore, W.H.; Pollard, J.L. [Iowa State Univ., Ames, IA (United States)
1995-11-01
This project involves the assessment of advanced coal preparation methods for removing trace elements from coal to reduce the potential for air toxic emissions upon combustion. Scanning electron microscopy-based automated image analysis (SEM-AIA) and advanced washability analyses are being applied with state-of-the-art analytical procedures to predict the removal of elements of concern by advanced column flotation and to confirm the effectiveness of preparation on the quality of quantity of clean coal produced. Specific objectives are to maintain an acceptable recovery of combustible product, while improving the rejection of mineral-associated trace elements. Current work has focused on determining conditions for controlling column flotation system across its operating range and on selection and analysis of samples for determining trace element cleanability.
COMSAC: Computational Methods for Stability and Control. Part 2
Fremaux, C. Michael (Compiler); Hall, Robert M. (Compiler)
2004-01-01
The unprecedented advances being made in computational fluid dynamic (CFD) technology have demonstrated the powerful capabilities of codes in applications to civil and military aircraft. Used in conjunction with wind-tunnel and flight investigations, many codes are now routinely used by designers in diverse applications such as aerodynamic performance predictions and propulsion integration. Typically, these codes are most reliable for attached, steady, and predominantly turbulent flows. As a result of increasing reliability and confidence in CFD, wind-tunnel testing for some new configurations has been substantially reduced in key areas, such as wing trade studies for mission performance guarantees. Interest is now growing in the application of computational methods to other critical design challenges. One of the most important disciplinary elements for civil and military aircraft is prediction of stability and control characteristics. CFD offers the potential for significantly increasing the basic understanding, prediction, and control of flow phenomena associated with requirements for satisfactory aircraft handling characteristics.
Huang, S; Lam, J.
2002-01-01
This paper studies the problem of stability region estimation and controller design for uncertain bilinear systems when linear controllers are used. Iterative linear matrix inequality (ILMI) algorithms are presented to estimate the closed-loop stability region and design the controllers. No tuning of parameters is needed in the design methods. The design aims to optimize between the size of the stability region, damping of the state variables, and the feedback gain.
Stabilization of complex network with hybrid impulsive and switching control
This paper studies the asymptotic stability properties of a class of complex dynamical networks under a hybrid impulsive and switching control. By utilizing the concept of impulsive control and the stability results for impulsive systems, some new criteria for global and local stability are established for this model. Some numerical examples and simulations are included to illustrate the effectiveness of the theoretical results
Stability notions and Lyapunov functions for sliding mode control systems
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...
Recent Advances in Iterative Learning Control
Jian-Xin XU
2005-01-01
In this paper we review the recent advances in three sub-areas of iterative learning control (ILC): 1) linear ILC for linear processes, 2) linear ILC for nonlinear processes which are global Lipschitz continuous (GLC), and 3) nonlinear ILC for general nonlinear processes. For linear processes, we focus on several basic configurations of linear ILC. For nonlinear processes with linear ILC, we concentrate on the design and transient analysis which were overlooked and missing for a long period. For general classes of nonlinear processes, we demonstrate nonlinear ILC methods based on Lyapunov theory, which is evolving into a new control paradigm.
Space Testing of the Advanced Instrument Controller
Goforth, Todd; Cannon, Scott; Lyke, James
1999-01-01
An extremely compact, low-power instrument controller and data processor system has been developed for space-based applications. Known as the Advanced Instrument Controller (AIC), this hybrid device contains both digital and analog components in a package less than 5 grams in weight and 2 x 3 em in size. Based on the Intel 8031151 microprocessor and implementing a superset of the 8051 instruction set, the AIC supports l28k of SRAM, 128k of EEPROM, four 8-bit parallel ports, six serial communi...
LHC beam stability and feedback control
Steinhagen, Ralph
2007-07-20
This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a
LHC beam stability and feedback control
This report presents the stability and the control of the Large Hadron Collider's (LHC) two beam orbits and their particle momenta using beam-based feedback systems. The aim of this report is to contribute to a safe and reliable LHC commissioning and machine operation. The first part of the analysis gives an estimate of the expected sources of orbit and energy perturbations that can be grouped into environmental sources, machine-inherent sources and machine element failures: the slowest perturbation due to ground motion, tides, temperature fluctuations of the tunnel and other environmental influences are described in this report by a propagation model that is both qualitatively and quantitatively supported by geophone and beam motion measurements at LEP and other CERN accelerators. The second part of this analysis deals with the control of the two LHC beams' orbit and energy through automated feedback systems. Based on the reading of the more than 1056 beam position monitors (BPMs) that are distributed over the machine, a central global feedback controller calculates new deflection strengths for the more than 1060 orbit corrector magnets (CODs) that are suitable to correct the orbit and momentum around their references. this report provides an analysis of the BPMs and CODs involved in the orbit and energy feedback. The BPMs are based on a wide-band time normaliser circuit that converts the transverse beam position reading of each individual particle bunch into two laser pulses that are separated by a time delay and transmitted through optical fibres to an acquisition card that converts the delay signals into a digital position. A simple error model has been tested and compared to the measurement accuracy of LHC type BPMs, obtained through beam-based measurements in the SPS. The average beam position is controlled through 1060 superconducting and individually powered corrector dipole magnets. The proposed correction in 'time-domain' consists of a proportional
Effects of STATCOM Control Mode on Voltage Stability
Ali Zare
2008-01-01
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...
Frequency domain stability criteria for fractional-order control systems
无
2006-01-01
This paper concerns about the frequency domain stability criteria for fractional-order control systems. On the base of characteristics of the fractional-order equations solutions, we consider the Nyquist stability criterion in a wider sense and obtain a more common means to analyze the stability of fractional-order systems conveniently. Finally, this paper illustrates the generalized stability criteria with an example to show the effect of the parameters variation on the fractional-order control systems.
External stability of fractional-order control systems
无
2006-01-01
The external stability of fractional-order continuous linear control systems described by both fractional-order state space representation and fractional-order transfer function is mainly investigated in this paper. In terms of Lyapunov's stability theory and the stability analysis of the integer-order linear control systems, the definitions of external stability for fractional-order control systems are presented. By using the theorems of the Mittag-Leffler function in two parameters, the necessary and sufficient conditions of external stability are directly derived. The illustrative examples and simulation results are also given.
AP1000's advanced control room
AP1000 is a passive Advanced Light Water Reactor designed by Westinghouse Electric Company to comply with the Electric Power Research Institute's (EPRI) Advanced Light Water Reactor (ALWR) Utility Requirements Document (URD). AP600, the predecessor to AP1000, received Design Certification by the US Nuclear Regulatory Commission (USNRC) in 1999. The AP1000 received its Final Design Approval in the Fall of 2004 and Design Certification is expected in the fall of 2005. During both of these licensing efforts a control room and Human Machine Interface (HMI) design process was submitted and approved. Realizing that Instrumentation and Control (I and C) and HMI technology changes rapidly, Westinghouse chose to delay the detailed design of the control room and operator interfaces. This allows the latest technology to be used when a plant is actually going to be built. That time has now come. This paper describes the preliminary designs of the AP1000 main control room (MCR) and HMI planned for use in new plants both in the United States and abroad. The paper also addresses how the certified design process is being conducted to complete the detailed HMI designs. (authors)
Wright, A.; Fleming, P.
2010-12-01
Wind turbines are complex, nonlinear, dynamic systems forced by aerodynamic, gravitational, centrifugal, and gyroscopic loads. The aerodynamics of wind turbines are nonlinear, unsteady, and complex. Turbine rotors are subjected to a complicated 3-D turbulent wind inflow field, with imbedded coherent vortices that drive fatigue loads and reduce lifetime. Design of control algorithms for wind turbines must account for multiple control objectives. Future large multi-megawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, while maximizing energy capture. Active damping should be added to these dynamic structures to maintain stability for operation in a complex environment. At the National Renewable Energy Laboratory (NREL), we have designed, implemented, and tested advanced controls to maximize energy extraction and reduce structural dynamic loads. These control designs are based on linear models of the turbine that are generated by specialized modeling software. In this paper, we present field test results of an advanced control algorithm to mitigate blade, tower, and drivetrain loads in Region 3.
Stability theory applications to laminar-flow control
Malik, Mujeeb R.
1987-01-01
In order to design Laminar Flow Control (LFC) configurations, reliable methods are needed for boundary-layer transition predictions. Among the available methods, there are correlations based upon R sub e, shape factors, Goertler number and crossflow Reynolds number. The most advanced transition prediction method is based upon linear stability theory in the form of the e sup N method which has proven to be successful in predicting transition in two- and three-dimensional boundary layers. When transition occurs in a low disturbance environment, the e sup N method provides a viable design tool for transition prediction and LFC in both 2-D and 3-D subsonic/supersonic flows. This is true for transition dominated by either TS, crossflow, or Goertler instability. If Goertler/TS or crossflow/TS interaction is present, the e sup N will fail to predict transition. However, there is no evidence of such interaction at low amplitudes of Goertler and crossflow vortices.
Advanced control design for hybrid turboelectric vehicle
Abban, Joseph; Norvell, Johnesta; Momoh, James A.
1995-08-01
The new environment standards are a challenge and opportunity for industry and government who manufacture and operate urban mass transient vehicles. A research investigation to provide control scheme for efficient power management of the vehicle is in progress. Different design requirements using functional analysis and trade studies of alternate power sources and controls have been performed. The design issues include portability, weight and emission/fuel efficiency of induction motor, permanent magnet and battery. A strategic design scheme to manage power requirements using advanced control systems is presented. It exploits fuzzy logic, technology and rule based decision support scheme. The benefits of our study will enhance the economic and technical feasibility of technological needs to provide low emission/fuel efficient urban mass transit bus. The design team includes undergraduate researchers in our department. Sample results using NASA HTEV simulation tool are presented.
Control Design for an Inertially Stabilized Rifle
White, Alejandro Porter
2007-01-01
An alternate method for mitigating the depredating physiological affects of a soldiers marksmanship due to combat stressors can be achieved through the design and implementation of a active stabilization system for small arms weapons. The INSTAR system is an innovative active stabilization system designed to decouple the shooterâ s disturbance effects from the barrel movement. The INSTAR system uses an piezoelectric actuator separating the barrel of the rifle from its stock to stabilize barr...
Nonlinear stability control and λ-bifurcation
Passive techniques for nonlinear stability control are presented for a model of fluidelastic instability. They employ the phenomena of λ-bifurcation and a generalization of it. λ-bifurcation occurs when a branch of flutter solutions bifurcates supercritically from a basic solution and terminates with an infinite period orbit at a branch of divergence solutions which bifurcates subcritically from the basic solution. The shape of the bifurcation diagram then resembles the greek letter λ. When the system parameters are in the range where flutter occurs by λ-bifurcation, then as the flow velocity increase the flutter amplitude also increases, but the frequencies of the oscillations decrease to zero. This diminishes the damaging effects of structural fatigue by flutter, and permits the flow speed to exceed the critical flutter speed. If generalized λ-bifurcation occurs, then there is a jump transition from the flutter states to a divergence state with a substantially smaller amplitude, when the flow speed is sufficiently larger than the critical flutter speed
JPL Advanced Thermal Control Technology Roadmap - 2008
Birur, Gaj
2008-01-01
This slide presentation reviews the status of thermal control technology at JPL and NASA.It shows the active spacecraft that are in vairous positions in the solar syatem, and beyond the solar system and the future missions that are under development. It then describes the challenges that the past missions posed with the thermal control systems. The various solutions that were implemented duirng the decades prior to 1990 are outlined. A review of hte thermal challenges of the future misions is also included. The exploration plan for Mars is then reviewed. The thermal challenges of the Mars Rovers are then outlined. Also the challenges of systems that would be able to be used in to explore Venus, and Titan are described. The future space telescope missions will also need thermal control technological advances. Included is a review of the thermal requirements for manned missions to the Moon. Both Active and passive technologies that have been used and will be used are reviewed. Those that are described are Mechanically Pumped Fluid Loops (MPFL), Loop Heat Pipes, an M3 Passive Cooler, Heat Siwtch for Space and Mars surface applications, phase change material (PCM) technology, a Gas Gap Actuateor using ZrNiH(x), the Planck Sorption Cooler (PCS), vapor compression -- Hybrid two phase loops, advanced pumps for two phase cooling loops, and heat pumps that are lightweight and energy efficient.
Advances in dynamical systems and control
Zgurovsky, Mikhail
2016-01-01
Focused on recent advances, this book covers theoretical foundations as well as various applications. It presents modern mathematical modeling approaches to the qualitative and numerical analysis of solutions for complex engineering problems in physics, mechanics, biochemistry, geophysics, biology and climatology. Contributions by an international team of respected authors bridge the gap between abstract mathematical approaches, such as applied methods of modern analysis, algebra, fundamental and computational mechanics, nonautonomous and stochastic dynamical systems on the one hand, and practical applications in nonlinear mechanics, optimization, decision making theory and control theory on the other. As such, the book will be of interest to mathematicians and engineers working at the interface of these fields. .
Stabilization control of a bumblebee in hovering and forward flight
Yan Xiong; Mao Sun
2009-01-01
Our previous study shows that the hovering and forward flight of a bumblebee do not have inherent stabil-ity (passive stability). But the bumblebees are observed to fly stably. Stabilization control must have been applied. In this study, we investigate the longitudinal stabilization con-trol of the bumblebee. The method of computational fluid dynamics is used to compute the control derivatives and the techniques of eigenvalue and eigenvector analysis and modal decomposition are used for solving the equations of motion. Controllability analysis shows that at all flight speeds consid-ered, although inherently unstable, the flight is controllable. By feedbacking the state variables, i.e. vertical and horizon-tal velocities, pitching rate and pitch angle (which can be measured by the sensory system of the insect), to produce changes in stroke angle and angle of attack of the wings, the flight can be stabilized, explaining why the bumblebees can fly stably even if they are passively unstable.
Advanced Wavefront Sensing and Control Testbed (AWCT)
Shi, Fang; Basinger, Scott A.; Diaz, Rosemary T.; Gappinger, Robert O.; Tang, Hong; Lam, Raymond K.; Sidick, Erkin; Hein, Randall C.; Rud, Mayer; Troy, Mitchell
2010-01-01
The Advanced Wavefront Sensing and Control Testbed (AWCT) is built as a versatile facility for developing and demonstrating, in hardware, the future technologies of wave front sensing and control algorithms for active optical systems. The testbed includes a source projector for a broadband point-source and a suite of extended scene targets, a dispersed fringe sensor, a Shack-Hartmann camera, and an imaging camera capable of phase retrieval wavefront sensing. The testbed also provides two easily accessible conjugated pupil planes which can accommodate the active optical devices such as fast steering mirror, deformable mirror, and segmented mirrors. In this paper, we describe the testbed optical design, testbed configurations and capabilities, as well as the initial results from the testbed hardware integrations and tests.
Transients in quasi-controllable systems. Overshooting, stability and instability
Kozyakin, V S; Pokrovskii, A V
2009-01-01
Families of regimes for control systems are studied possessing the so called quasi-controllability property that is similar to the Kalman controllability property. A new approach is proposed to estimate the degree of transients overshooting in quasi-controllable systems. This approach is conceptually related with the principle of bounded regimes absence in the absolute stability problem. Its essence is in obtaining of constructive a priori bounds for degree of overshooting in terms of the so called quasi-controllability measure. It is shown that relations between stability, asymptotic stability and instability for quasi-controllable systems are similar to those for systems described by linear differential or difference equations in the case when the leading eigenvalue of the corresponding matrix is simple. The results are applicable for analysis of transients, classical absolute stability problem, stability problem for desynchronized systems and so on.
Zhong Cao
2014-01-01
Full Text Available This paper investigates robust simultaneous stabilization (RSS control method for two port-controlled Hamiltonian (PCH systems and proposes results on the design of simultaneous stabilization controller with parameters for such systems. Firstly, two PCH systems are studied. Using the dissipative Hamiltonian structural properties, the systems are combined to generate an augmented PCH system. When there are external disturbances in the systems, a robust controller with parameters is designed for the systems. Secondly, an algorithm for solving parameters of the controller is proposed with symbolic computation. Finally, an illustrative example is presented to show that the RSS controller obtained in this paper works very well.
Power system stabilizers based on modern control techniques
Malik, O.P.; Chen, G.P.; Zhang, Y.; El-Metwally, K. [Calgary Univ., AB (Canada). Dept. of Electrical and Computer Engineering
1994-12-31
Developments in digital technology have made it feasible to develop and implement improved controllers based on sophisticated control techniques. Power system stabilizers based on adaptive control, fuzzy logic and artificial networks are being developed. Each of these control techniques possesses unique features and strengths. In this paper, the relative performance of power systems stabilizers based on adaptive control, fuzzy logic and neural network, both in simulation studies and real time tests on a physical model of a power system, is presented and compared to that of a fixed parameter conventional power system stabilizer. (author) 16 refs., 45 figs., 3 tabs.
Prototyping Advanced Control Systems on FPGA
Simard Stéphane
2009-01-01
Full Text Available In advanced digital control and mechatronics, FPGA-based systems on a chip (SoCs promise to supplant older technologies, such as microcontrollers and DSPs. However, the tackling of FPGA technology by control specialists is complicated by the need for skilled hardware/software partitioning and design in order to match the performance requirements of more and more complex algorithms while minimizing cost. Currently, without adequate software support to provide a straightforward design flow, the amount of time and efforts required is prohibitive. In this paper, we discuss our choice, adaptation, and use of a rapid prototyping platform and design flow suitable for the design of on-chip motion controllers and other SoCs with a need for analog interfacing. The platform consists of a customized FPGA design for the Amirix AP1000 PCI FPGA board coupled with a multichannel analog I/O daughter card. The design flow uses Xilinx System Generator in Matlab/Simulink for system design and test, and Xilinx Platform Studio for SoC integration. This approach has been applied to the analysis, design, and hardware implementation of a vector controller for 3-phase AC induction motors. It also has contributed to the development of CMC's MEMS prototyping platform, now used by several Canadian laboratories.
Generalized Predictive Control: Step Responses and Stability Thoery
Gomma, H.W.; Owens, D.H.
2000-01-01
This paper presents new results that use step response data to produce sufficient conditions to guarantee the stability of the closed loop system in Generalized Predictive Control (GPC) . The analysis produces easily checked conditions that provide considerable insight into the effect of parameters such as prediction horizons and control weightings on stability characteristics.
Stability of Controlled Hamilton Systems Excited by Gaussian White Noise
SHANG Mei; GUO Yong-xin; MEI Feng-xiang
2008-01-01
A new method is introduced in this paper. This method can be used to study the stability of controlled holonomic Hamilton systems under disturbance of Gaussian white noise. At first, the motion equation of controlled holonomic Hamilton systems excited by Gaussian noise is formulated. A theory to stabilize the system is provided. Finally, one example is given to illustrate the application procedures.
Response Based Emergency Control System for Power System Transient Stability
Huaiyuan Wang; Baohui Zhang; Zhiguo Hao
2015-01-01
A transient stability control system for the electric power system composed of a prediction method and a control method is proposed based on trajectory information. This system, which is independent of system parameters and models, can detect the transient stability of the electric power system quickly and provide the control law when the system is unstable. Firstly, system instability is detected by the characteristic concave or convex shape of the trajectory. Secondly, the control method is...
Advances in stability theory at the end of the 20th century
Martynyuk, AA
2003-01-01
This volume presents surveys and research papers on various aspects of modern stability theory, including discussions on modern applications of the theory, all contributed by experts in the field. The volume consists of four sections that explore the following directions in the development of stability theory: progress in stability theory by first approximation; contemporary developments in Lyapunov''s idea of the direct method; the stability of solutions to periodic differential systems; and selected applications. Advances in Stability Theory at the End of the 20th Century will interest postgraduates and researchers in engineering fields as well as those in mathematics.
The advanced controls program at Oak Ridge National Laboratory
The Oak Ridge National Laboratory (ORNL), under sponsorship of the US Department of Energy (DOE), is conducting research that will lead to advanced, automated control of new liquid-metal-reactor (LMR) nuclear power plants. Although this program of research (entitled the ''Advanced Controls Program'') is focused on LMR technology, it will be capable of providing control design, test, and qualification capability for other advanced reactor designs (e.g., the advanced light water reactor [ALWR] and high temperature gas-cooled reactor [HTGR] designs), while also benefiting existing nuclear plants. The Program will also have applicability to complex, non-nuclear process control environments (e.g., petrochemical, aerospace, etc.). The Advanced Controls Program will support capabilities throughout the entire plant design life cycle, i.e., from the initial interactive first-principle dynamic model development for the process, systems, components, and instruments through advanced control room qualification. The current program involves five principal areas of research activities: (1) demonstrations of advanced control system designs, (2) development of an advanced controls design environment, (3) development of advanced control strategies, (4) research and development (R ampersand D) in human-system integration for advanced control system designs, and (5) testing and validation of advanced control system designs. Discussion of the research in these five areas forms the basis of this paper. Also included is a description of the research directions of the program. 8 refs
Advanced Emissions Control Development Program: Phase III
G.T. Amrhein; R.T. Bailey; W. Downs; M.J. Holmes; G.A. Kudlac; D.A. Madden
1999-07-01
The primary objective of the Advanced Emissions Control Development Program (AECDP) is to develop practical, cost-effective strategies for reducing the emissions of air toxics from coal-fired boilers. The project goal is to effectively control air toxic emissions through the use of conventional flue gas clean-up equipment such as electrostatic precipitators (ESPs), fabric filters (baghouses - BH), and wet flue gas desulfurization systems (WFGD). Development work concentrated on the capture of trace metals, fine particulate, hydrogen chloride and hydrogen fluoride, with an emphasis on the control of mercury. The AECDP project is jointly funded by the US Department of Energy's Federal Energy Technology Center (DOE), the Ohio Coal Development Office within the Ohio Department of Development (OCDO), and Babcock and Wilcox, a McDermott company (B and W). This report discusses results of all three phases of the AECDP project with an emphasis on Phase III activities. Following the construction and evaluation of a representative air toxics test facility in Phase I, Phase II focused on characterization of the emissions of mercury and other air toxics and the control of these emissions for typical operating conditions of conventional flue gas clean-up equipment. Some general comments that can be made about the control of air toxics while burning a high-sulfur bituminous coal are as follows: (1) particulate control devices such as ESP's and baghouses do a good job of removing non-volatile trace metals, (2) particulate control devices (ESPs and baghouses) effectively remove the particulate-phase mercury, but the particulate-phase mercury was only a small fraction of the total for the coals tested, (3) wet scrubbing can effectively remove hydrogen chloride and hydrogen fluoride, and (4) wet scrubbers show good potential for the removal of mercury when operated under certain conditions, however, for certain applications, system enhancements can be required to achieve
Passive and active feedback stabilization schemes being considered in Korea Superconducting Tokamak Advanced Research (KSTAR) device for the stabilization of the resistive magnetohydrodynamic modes such as the resistive wall and the neoclassical tearing are briefly introduced. A short summary is also presented on the tokamak simulation results of disruption dynamics and load in the KSTAR tokamak obtained using the tokamak simulation code (TSC)
How to lose money with advanced controls
This paper reports that advanced control is a well established technology in the oil and petrochemical industries, and it is tempting to believe that a large portion of its users have captured the greatest share of the available benefits. However, despite massive investments in hardware, few companies have fully exploited the opportunities made available by this investment. In the Western world probably about 85% of the total investment justified on existing plants has already been committed. The benefits captured, however, are probably less than 50% of those readily available. Assuming this investment was justified on a three year payback, the incremental cost to finish the job should pay back in about six months. So why isn't everyone doing it? The following gives guidance on how to maintain, or even worsen the status quo. Known as the Whitehouse Rules, violation of most of them could cause a significant improvement in process profitability
A STABILITY THEOREM FOR CONSTRAINED OPTIMAL CONTROL PROBLEMS
M.H. Farag
2004-01-01
This paper presents the stability of difference approximations of an optimal control problem for a quasilinear parabolic equation with controls in the coefficients, boundary conditions and additional restrictions. The optimal control problem has been convered to one of the optimization problem using a penalty function technique. The difference approximations problem for the considered problem is obtained. The estimations of stability of the solution of difference approximations problem are proved. The stability estimation of the solution of difference approximations problem by the controls is obtained.
Improvement of Transient Stability using Fuzzy Logic Controlled SMES
D. Harikrishna
2011-12-01
Full Text Available In this paper, the transient stability of an electric power system is improved by fuzzy logic controlled superconducting magnetic energy storage (SMES. The effectiveness of the proposed fuzzy controlled SMES is compared with a conventional proportional integral (PI controlled SMES. In addition to it a comparison between the fuzzy controlled SMES and fuzzy controlled braking resistor (BR is also carried out. The simulation results show that under 3 phase fault, the fuzzy controlled SMES performance is better than PI controlled SMES. Furthermore, the performance of SMES is better than that of BR. The proposed method provides a very simple and effective means of improvement of transient stability.
Fault Tolerant Control: A Simultaneous Stabilization Result
Stoustrup, Jakob; Blondel, V.D.
2004-01-01
This paper discusses the problem of designing fault tolerant compensators that stabilize a given system both in the nominal situation, as well as in the situation where one of the sensors or one of the actuators has failed. It is shown that such compensators always exist, provided that the system...
Predictive Control for Visual Servo Stabilization of Nonholonomic Mobile Robots
CAO Zheng-Cai; YIN Long-Jie; FU Yi-Li; LIU Tian-Long
2013-01-01
Visual servo stabilization of nonholonomic mobile robots has gained extensive attention.However,currently,the solution of the problem does not consider both the visibility constraints and the actuator limitations,so the designed controller is difficult to realize satisfactory performance in practical application.In this paper,a predictive controller for the visual servo stabilization of a mobile robot is presented.Firstly,a kinematic predictive stabilization controller utilized to generate the command of velocity is introduced.Then,in order to make the actual velocity of the mobile robot asymptotically approach to the desired one,a dynamic predictive controller is designed.The proposed predictive controller can deal with the constraints easily.Finally,several simulations are performed,and the results illustrate that the proposed control scheme is effective to solve the visual servo stabilization problem.
Hybrid stabilizing control on a real mobile robot
Oelen, Wilco; Berghuis, Harry; Nijmeijer, Henk; Canudas de Wit, Carlos
1995-01-01
To establish empirical verification of a stabilizing controller for nonholonomic systems, the authors implement a hybrid control concept on a 2-DOF mobile robot. Practical issues of velocity control are also addressed through a velocity controller which transforms the mobile robot to a new system wi
Power system transient stability preventive and emergency control
Ruiz-Vega, Daniel; Wehenkel, Louis; Ernst, Damien; Pizano-Martinez, Alejandro; Fuerte-Esquivel, Claudio
2014-01-01
A general approach to real-time transient stability control is described, yielding various complementary techniques: pure preventive, open loop emergency, and closed loop emergency controls. Recent progress in terms of a global transient stability constrained optimal power flow are presented, yielding in a scalable nonlinear programming formulation which allows to take near-optimal decisions for preventive control with a computing budget corresponding only to a few runs of standard optimal po...
Stabilization Based Networked Predictive Controller Design for Switched Plants
Routh, Avijit; Das, Sourav; Das, Saptarshi; Pan, Indranil
2012-01-01
Stabilizing state feedback controller has been designed in this paper for a switched DC motor plant, controlled over communication network. The switched system formulation for the networked control system (NCS) with additional switching in a plant parameter along with the switching due to random packet losses, have been formulated as few set of non-strict Linear Matrix Inequalities (LMIs). In order to solve non-strict LMIs using standard LMI solver and to design the stabilizing state feedback...
Robust Stabilization of Nonlinear Systems with Uncertain Varying Control Coefficient
Zaiyue Yang
2014-01-01
Full Text Available This paper investigates the stabilization problem for a class of nonlinear systems, whose control coefficient is uncertain and varies continuously in value and sign. The study emphasizes the development of a robust control that consists of a modified Nussbaum function to tackle the uncertain varying control coefficient. By such a method, the finite-time escape phenomenon has been prevented when the control coefficient is crossing zero and varying its sign. The proposed control guarantees the asymptotic stabilization of the system and boundedness of all closed-loop signals. The control performance is illustrated by a numerical simulation.
An advanced precision analysis of the SM vacuum stability
Bednyakov, A V
2016-01-01
The talk is devoted to the problem of stability of the Standard Model vacuum. The effective potential for the Higgs field, which can potentialy exhibit additional, deeper minimum, is considered as a convenient tool for addressing the problem. Different methods and approximations used to calculate the potential are considered. Special attention is paid to the renomalization-group approach that allows one to carry out three-loop analysis of the problem. By means of an explicit gauge-independent procedure the absolute stability bounds on the observed Higgs and top-quark masses are derived. The importance of high-order corrections is demonstrated. In addition, potential metastablity of the SM is discussed together with modifications of the analysis due to some New Physics.
Recent advances in the stability theory of toroidal plasmas
Many of the most persistent instabilities of a magnetically confined plasma have short wavelength perpendicular to the magnetic field but long wavelength parallel to it. Such instabilities are difficult to treat in a toroidal system because the simple eikonal representation of short wavelength oscillations. X(r) = Y(r) esup(iS(r)/γ) with γ << 1 proves to be incompatible with the other requirements of toroidal periodicity and long parallel wavelength (which would require BETA.ΔS = O). A new method of representing perturbations in a torus will be outlined. By using this, the two-dimensional stability problem posed by an axisymmetric toroidal equilibrium can be reduced to that of solving a one-dimensional eigenvalue equation. This technique essentially completes the linear stability theory of magnetohydrodynamic modes in a toroidal plasma, and is also applicable to the investigation of micro-instabilities that are described by the Vlasov-Maxwell equations. (author)
Survey, alignment, and beam stability at the Advanced Light Source
This paper describes survey and alignment at the Lawrence Berkeley Laboratories Advanced Light Source (ALS) accelerators from 1993 to 1997. The ALS is a third generation light source requiring magnet alignment to within 150 microns. To accomplish this, a network of monuments was established and maintained. Monthly elevation surveys show the movement of the floor over time. Inclinometers have recently been employed to give real time information about magnet, vacuum tank and magnet girder motion in the ALS storage ring
Hybrid stabilizing control on a real mobile robot
Oelen, Wilco; Berghuis, Harry; Nijmeijer, Henk; Canudas De Wit, Carlos
1995-01-01
To establish empirical verification of a stabilizing controller for nonholonomic systems, the authors implement a hybrid control concept on a 2-DOF mobile robot. Practical issues of velocity control are also addressed through a velocity controller which transforms the mobile robot to a new system with linear and angular velocity inputs. Experiments in the physical meaning of different controller components provide insights which result in significant improvements in controller performance
Improvement of Transient Stability using Fuzzy Logic Controlled SMES
D Harikrishna; N.V. Srikanth; Y. Chandrasekhar
2011-01-01
In this paper, the transient stability of an electric power system is improved by fuzzy logic controlled superconducting magnetic energy storage (SMES). The effectiveness of the proposed fuzzy controlled SMES is compared with a conventional proportional integral (PI) controlled SMES. In addition to it a comparison between the fuzzy controlled SMES and fuzzy controlled braking resistor (BR) is also carried out. The simulation results show that under 3 phase fault, the fuzzy controlled SMES per...
Advanced Applications of Subsea Control Systems
Technology transfer is one of the main arguments Norwegian companies have for getting involved in difficult markets like Angola. There is great need for sub sea technology in Angola, and Kvaerner Oilfield Products is one of the companies that have successfully fought for contracts in this lucrative market. Field operator TotalFinaElf Exploration and Production Angola has awarded Kvaerner Oilfield Products a USD 3.1 million contract for pre-engineering and qualification testing of the sub sea production systems for the Dalia field offshore Angola. Kvaerner Oilfield Products has already started pre-engineering and testing activity. The sub sea production system includes 42 Xmas trees for controlling the well stream, nine manifolds as well as related control equipment. As sub sea technology improves and advances, equipment that is more complex is being placed on the seabed and downhole environments. Factors such as the cost of the umbilical, increased noise immunity and speed requirements will almost certainly result in optical communications being widely adopted for future system designs. However; in the immediate future operators are likely to insist on backup electrical communications due to the immaturity of certain aspects such as Wetmate optical connectors, fibre handling and fibre degradation. Perhaps the single greatest advantage of open standard sub sea networking is derived from the exploitation of the growing range of third party intelligent instrumentation available on the market. This instrumentation when properly integrated into a sensor to boardroom data management system allows unparalleled control to be delivered to the user at a total cost of installation which can be radically less than conventional technology. It can provide a compelling case for adoption of true open standards. In order to deliver power over any significant distance it is necessary to consider the losses in the transmission medium. The major constraint in the sub sea industry is
Solar Dynamic Power System Stability Analysis and Control
Momoh, James A.; Wang, Yanchun
1996-01-01
The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.
Microgrid Stability Controller Based on Adaptive Robust Total SMC
Xiaoling Su; Minxiao Han; Josep M. Guerrero; Hai Sun
2015-01-01
This paper presents a microgrid stability controller (MSC) in order to provide existing distributed generation units (DGs) the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding...
Power System Stabilizer Based on Global Fuzzy Sliding Mode Control
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...
ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM
HUMPHREYS,DA; FERRON,JR; GAROFALO,AM; HYATT,AW; JERNIGAN,TC; JOHNSON,RD; LAHAYE,RJ; LEUER,JA; OKABAYASHI,M; PENAFLOR,BG; SCOVILLE,JT; STRAIT,EJ; WALKER,ML; WHYTE,DG
2002-10-01
A271 ADVANCED TOKAMAK OPERATION USING THE DIII-D PLASMA CONTROL SYSTEM. The principal focus of experimental operations in the DIII-D tokamak is the advanced tokamak (AT) regime to achieve, which requires highly integrated and flexible plasma control. In a high performance advanced tokamak, accurate regulation of the plasma boundary, internal profiles, pumping, fueling, and heating must be well coordinated with MHD control action to stabilize such instabilities as tearing modes and resistive wall modes. Sophisticated monitors of the operational regime must provide detection of off-normal conditions and trigger appropriate safety responses with acceptable levels of reliability. Many of these capabilities are presently implemented in the DIII-D plasma control system (PCS), and are now in frequent or routine operational use. The present work describes recent development, implementation, and operational experience with AT regime control elements for equilibrium control, MHD suppression, and off-normal event detection and response.
Advanced h∞ control towards nonsmooth theory and applications
Orlov, Yury V
2014-01-01
This compact monograph is focused on disturbance attenuation in nonsmooth dynamic systems, developing an H∞ approach in the nonsmooth setting. Similar to the standard nonlinear H∞ approach, the proposed nonsmooth design guarantees both the internal asymptotic stability of a nominal closed-loop system and the dissipativity inequality, which states that the size of an error signal is uniformly bounded with respect to the worst-case size of an external disturbance signal. This guarantee is achieved by constructing an energy or storage function that satisfies the dissipativity inequality and is then utilized as a Lyapunov function to ensure the internal stability requirements. Advanced H∞ Control is unique in the literature for its treatment of disturbance attenuation in nonsmooth systems. It synthesizes various tools, including Hamilton–Jacobi–Isaacs partial differential inequalities as well as Linear Matrix Inequalities. Along with the finite-dimensional treatment, the synthesis is exten...
Response Based Emergency Control System for Power System Transient Stability
Huaiyuan Wang
2015-11-01
Full Text Available A transient stability control system for the electric power system composed of a prediction method and a control method is proposed based on trajectory information. This system, which is independent of system parameters and models, can detect the transient stability of the electric power system quickly and provide the control law when the system is unstable. Firstly, system instability is detected by the characteristic concave or convex shape of the trajectory. Secondly, the control method is proposed based on the analysis of the slope of the state plane trajectory when the power system is unstable. Two control objectives are provided according to the methods of acquiring the far end point: one is the minimal cost to restore the system to a stable state; the other one is the minimal cost to limit the maximum swing angle. The simulation indicates that the mentioned transient stability control system is efficient.
Optimal boundary control and boundary stabilization of hyperbolic systems
Gugat, Martin
2015-01-01
This brief considers recent results on optimal control and stabilization of systems governed by hyperbolic partial differential equations, specifically those in which the control action takes place at the boundary. The wave equation is used as a typical example of a linear system, through which the author explores initial boundary value problems, concepts of exact controllability, optimal exact control, and boundary stabilization. Nonlinear systems are also covered, with the Korteweg-de Vries and Burgers Equations serving as standard examples. To keep the presentation as accessible as possible, the author uses the case of a system with a state that is defined on a finite space interval, so that there are only two boundary points where the system can be controlled. Graduate and post-graduate students as well as researchers in the field will find this to be an accessible introduction to problems of optimal control and stabilization.
Stability and Sensitivity Analysis of Fuzzy Control Systems. Mechatronics Applications
Radu-Emil Precup
2006-01-01
Full Text Available The development of fuzzy control systems is usually performed by heuristicmeans, incorporating human skills, the drawback being in the lack of general-purposedevelopment methods. A major problem, which follows from this development, is theanalysis of the structural properties of the control system, such as stability, controllabilityand robustness. Here comes the first goal of the paper, to present a stability analysismethod dedicated to fuzzy control systems with mechatronics applications based on the useof Popov’s hyperstability theory. The second goal of this paper is to perform the sensitivityanalysis of fuzzy control systems with respect to the parametric variations of the controlledplant for a class of servo-systems used in mechatronics applications based on theconstruction of sensitivity models. The stability and sensitivity analysis methods provideuseful information to the development of fuzzy control systems. The case studies concerningfuzzy controlled servo-systems, accompanied by digital simulation results and real-timeexperimental results, validate the presented methods.
Stability of the Electroweak Vacuum: Gauge Independence and Advanced Precision.
Bednyakov, A V; Kniehl, B A; Pikelner, A F; Veretin, O L
2015-11-13
We perform a manifestly gauge-independent analysis of the vacuum stability in the standard model including two-loop matching, three-loop renormalization group evolution, and pure QCD corrections through four loops. All these ingredients are exact, except that light-fermion masses are neglected. We in turn apply the criterion of nullifying the Higgs self-coupling and its beta function in the modified minimal-subtraction scheme and a recently proposed consistent method for determining the true minimum of the effective Higgs potential that also avoids gauge dependence. Exploiting our knowledge of the Higgs-boson mass, we derive an upper bound on the pole mass of the top quark by requiring that the standard model be stable all the way up to the Planck mass scale and conservatively estimate the theoretical uncertainty. This bound is compatible with the Monte Carlo mass quoted by the Particle Data Group at the 1.3σ level. PMID:26613431
Stabilizing model predictive control for constrained nonlinear distributed delay systems.
Mahboobi Esfanjani, R; Nikravesh, S K Y
2011-04-01
In this paper, a model predictive control scheme with guaranteed closed-loop asymptotic stability is proposed for a class of constrained nonlinear time-delay systems with discrete and distributed delays. A suitable terminal cost functional and also an appropriate terminal region are utilized to achieve asymptotic stability. To determine the terminal cost, a locally asymptotically stabilizing controller is designed and an appropriate Lyapunov-Krasoskii functional of the locally stabilized system is employed as the terminal cost. Furthermore, an invariant set for locally stabilized system which is established by using the Razumikhin Theorem is used as the terminal region. Simple conditions are derived to obtain terminal cost and terminal region in terms of Bilinear Matrix Inequalities. The method is illustrated by a numerical example. PMID:21232739
Xiao-xing WANG; Xiao-xi LV; Jia-ping WANG; Hui-min YAN; Zi-yan WANG; Han-zhi LIU; Xiao-ming FU
2013-01-01
Aim:Toll-like receptor 2 (TLR2) signaling plays a critical role in the initiation of atherosclerosis.The aim of this study was to investigate whether blocking TLR2 activity could produce therapeutic effects on advanced atherosclerosis.Methods:Forty-week old apolipoprotein E-deficient (ApoE-/-) mice fed on a normal diet were intravenously injected with a TLR2-neutralizing antibody or with an isotype-matched IgG for 18 weeks.Double-knockout ApoE-/-Tlr2-/-mice were taken as a positive control.At the end of the treatments,the plasma lipid levels were measured,and the plaque morphology,pro-inflammatory cytokines expression and apoptosis in arteries were analyzed.In the second part of this study,6-week old ApoE-/-and ApoE-/-Tlr2-/-mice fed on a high-cholesterol diet for 12 to 24 weeks,the expression levels of TLR2 and apoptotic markers in arteries were examined.Results:Blockade of TLR2 activity with TLR2-neutralizing antibody or knockout of Tlr2 gene did not alter the plasma lipid levels in ApoE-/-mice.However,the pharmacologic and genetic manipulations significantly reduced the plaque size and vessel stenosis,and increased plaque stability in the brachiocephalic arteries.The protective effects of TLR2 antagonism were associated with the suppressed expression of pro-inflammatory cytokines IL-6 and TNF-α and the inactivation of transcription factors NF-KB and Stat3.In addition,blocking TLR2 activity attenuated ER stress-induced macrophage apoptosis in the brachiocephalic arteries,which could promote the resolution of necrotic cores in advanced atherosclerosis.Moreover,high-cholesterol diet more prominently accelerated atherosclerotic formation and increased the expression of pro-apoptotic protein CHOP and apoptosis in ApoE-/-mice than in ApoE-/-Tlr2-/-mice.Conclusion:The pharmacologic or genetic blockade of TLR2 activity diminishes and stabilizes advanced atherosclerotic lesions in ApoE-/-mice.Thus,targeting TLR2 signaling may be a promising therapeutic strategy against
Applications of Computational Methods for Dynamic Stability and Control Derivatives
Green, Lawrence L.; Spence, Angela M.
2004-01-01
Initial steps in the application o f a low-order panel method computational fluid dynamic (CFD) code to the calculation of aircraft dynamic stability and control (S&C) derivatives are documented. Several capabilities, unique to CFD but not unique to this particular demonstration, are identified and demonstrated in this paper. These unique capabilities complement conventional S&C techniques and they include the ability to: 1) perform maneuvers without the flow-kinematic restrictions and support interference commonly associated with experimental S&C facilities, 2) easily simulate advanced S&C testing techniques, 3) compute exact S&C derivatives with uncertainty propagation bounds, and 4) alter the flow physics associated with a particular testing technique from those observed in a wind or water tunnel test in order to isolate effects. Also presented are discussions about some computational issues associated with the simulation of S&C tests and selected results from numerous surface grid resolution studies performed during the course of the study.
Power system dynamics stability and control
Padiyar, K R
2008-01-01
Modern power systems tend to be very Complex not only due to increasing Demand for quality power, but also on Account of extensive interconnections and increasing dependence on control for optimum utilization for existing resources. A good Knowledge of system dynamics and control is Essential for secure operation of the system. This book is intended to serve the needs of the Student and practicing engineers. A Large number of illustrative examples are included to provide an insight into the application of the theory.
Transient stability enhancement via coordinated excitation and UPFC control
Huayuan Chen; Youyi Wang; Rujing Zhou [Nanyang Technological University (Singapore). School of EEE
2002-01-01
This paper discusses coordinated excitation and UPFC control to improve power system transient stability. The power system is linearized through direct feedback linearization technique. Robust approach is employed to deal with the uncertainties caused by parameter variations and the inclusion of UPFC controller. Only local measurements are required for designing the excitation controller. The series branch of UPFC is designed to damp the power oscillation during transient period. The shunt branch aims at maintaining bus voltage. The performance of the controllers is tested on a single-machine infinite-bus (SMIB) power system. Simulation results show that both of the series and shunt branch of UPFC help improve transient stability. (Author)
Ideal MHD Stability Prediction and Required Power for EAST Advanced Scenario
Chen, Junjie; Li, Guoqiang; Qian, Jinping; Liu, Zixi
2012-11-01
The Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. The ideal magnetohydrodynamic (MHD) stability and required power for the EAST advanced tokamak (AT) scenario with negative central shear and double transport barrier (DTB) are investigated. With the equilibrium code TOQ and stability code GATO, the ideal MHD stability is analyzed. It is shown that a moderate ratio of edge transport barriers' (ETB) height to internal transport barriers' (ITBs) height is beneficial to ideal MHD stability. The normalized beta βN limit is about 2.20 (without wall) and 3.70 (with ideal wall). With the scaling law of energy confinement time, the required heating power for EAST AT scenario is calculated. The total heating power Pt increases as the toroidal magnetic field BT or the normalized beta βN is increased.
Ideal MHD Stability Prediction and Required Power for EAST Advanced Scenario
陈均杰; 李国强; 钱金平; 刘子奚
2012-01-01
The Experimental Advanced Superconducting Tokamak (EAST) is the first fully superconducting tokamak with a D-shaped cross-sectional plasma presently in operation. The ideal magnetohydrodynamic (MHD) stability and required power for the EAST advanced tokamak (AT) scenario with negative central shear and double transport barrier (DTB) are investigated. With the equilibrium code TOQ and stability code GATO, the ideal MHD stability is analyzed. It is shown that a moderate ratio of edge transport barriers' (ETB) height to internal transport barriers' (ITBs) height is beneficial to ideal MHD stability. The normalized beta/3N limit is about 2.20 (without wall) and 3.70 (with ideal wall). With the scaling law of energy confinement time, the required heating power for EAST AT scenario is calculated. The total heating power Pt increases as the toroidal magnetic field BT or the normalized beta βN is increased.
Preventive Control Using Generation Rescheduling for Transient Stability
Lee, Jong Seock; Lee, Byong Jun; Kwon, Sae Hyuk; Choi, Sun Kyu [Korea University, Seoul (Korea); Nam, Hae Kon [Chonnam National University, Kwangu (Korea); Choo, Jin Boo; Jeon, Dong Hoon [Korea Electric Power Research Institute, Taejeon (Korea)
2002-06-01
Preventive control has to solve two important problems. The first is fast and accurate severity assessment of instability originated from the occurrence of a dangerous contingency. The second is to choose an action able to stabilize it. In this paper we assess contingencies in power systems using PASF(Power Angle Shape Filtering) and control power systems by a generation rescheduling. The control action stabilize the whole set of harmful contingencies simultaneously. Note that conventional time-domain transient stability methods can hardly tackle preventive control. So, we study the preventive control using off-line method. The proposed method is applied to prevent and to correct loss of synchronism of all the generators in a operating systems data. (author). 5 refs., 6 figs., 5 tabs.
Stability Analysis on Speed Control System of Autonomous Underwater Vehicle
LI Ye; PANG Yong-jie; WAN Lei; WANG Fang; LIAO Yu-lei
2009-01-01
The stability of the motion control system is one of the decisive factors of the control quality for Autonomous Underwater Vehicle (AUV).The divergence of control,which the unstable system may be brought about,is fatal to the operation of AUV.The stability analysis of the PD and S-surface speed controllers based on the Lyapunov' s direct method is proposed in this paper.After decoupling the six degree-of-freedom (DOF) motions of the AUV,the axial dynamic behavior is discussed and the condition is deduced,in which the parameters selection within stability domain can guarantee the system asymptotically stable.The experimental results in a tank and on the sea have successfully verified the algorithm reliability,which can be served as a good reference for analyzing other AUV nonlinear control systems.
A class of stabilizing controllers for flexible multibody systems
Joshi, Suresh M.; Kelkar, Atul G.; Maghami, Peiman G.
1995-01-01
The problem of controlling a class of nonlinear multibody flexible space systems consisting of a flexible central body to which a number of articulated appendages are attached is considered. Collocated actuators and sensors are assumed, and global asymptotic stability of such systems is established under a nonlinear dissipative control law. The stability is shown to be robust to unmodeled dynamics and parametric uncertainties. For a special case in which the attitude motion of the central body is small, the system, although still nonlinear, is shown to be stabilized by linear dissipative control laws. Two types of linear controllers are considered: static dissipative (constant gain) and dynamic dissipative. The static dissipative control law is also shown to provide robust stability in the presence of certain classes of actuator and sensor nonlinearities and actuator dynamics. The results obtained for this special case can also be readily applied for controlling single-body linear flexible space structures. For this case, a synthesis technique for the design of a suboptimal dynamic dissipative controller is also presented. The results obtained in this paper are applicable to a broad class of multibody and single-body systems such as flexible multilink manipulators, multipayload space platforms, and space antennas. The stability proofs use the Lyapunov approach and exploit the inherent passivity of such systems.
Stabilizing equilibrium by linear feedback control for controlling chaos in Chen system
Costa, V A [Departamento de Ciencias Basicas, Facultad de IngenierIa (UNLP), La Plata (Argentina); Gonzalez, G A, E-mail: vacosta@ing.unlp.edu.ar, E-mail: ggonzal@fi.ub.ar [Departamento de Matematica, Facultad de Ingenieria (UBA), Buenos Aires (Argentina)
2011-03-01
Stabilization of a chaotic system in one of its unstable equilibrium points by applying small perturbations is studied. A two-stage control strategy based on linear feedback control is applied. Improvement of system performance is addressed by exploiting the ergodicity of the original dynamics and using Lyapunov stability results for control design. Extension to the not complete observability case is also analyzed.
Stability Analysis and Controller Synthesis for Digital Single-Loop Voltage-Controlled Inverters
Wang, Xiongfei; Loh, Poh Chiang; Blaabjerg, Frede
2016-01-01
This paper analyzes first the stability of single-loop digital voltage control scheme for the LC-filtered voltage source inverters. It turns out that the phase lag, caused by the time delay of digital control system and by the use of integral controller, can stabilize the voltage loop without dam...
Microgrid Stability Controller Based on Adaptive Robust Total SMC
Su, Xiaoling; Han, Minxiao; Guerrero, Josep M.; Sun, Hai
2015-01-01
This paper presents a microgrid stability controller (MSC) in order to provide existing DGs the additional functionality of working in islanding mode without changing their control strategies in grid-connected mode and to enhance the stability of the microgrid. Microgrid operating characteristics...... and mathematical models of the MSC indicate that the system is inherently nonlinear and time-variable. Therefore, this paper proposes an adaptive robust total sliding-mode control (ARTSMC) system for the MSC. It is proved that the ARTSMC system is insensitive to parametric uncertainties and external...
Preventive Control Using Generation Rescheduling for Transient Stability
Choi, Sun Kyu; Lee, Jong Seock; Lee, Byung Jun; Kwon, Sae Hyuk [Korea University (Korea); Nam, H.K. [Chonnam National University (Korea); Choo, J.B.; Lee, Koung Guk [KEPRI KEPCO (Korea); Yoon, S.H. [PROCOM Systems Co., Ltd. (Korea)
2001-07-01
This paper describes preventive control for transient stability. Preventive control encompasses in general a twofold problem: Severity assessment of a instability originating from the occurrence of a instability originating from the occurrence of a dangerous contingency, and Choice of an action able to stabilize it. In this a paper we assess contingencies in a power systems using PASF(Power Angle Shape Filtering) and control power systems by a generation rescheduling. The proposed method is applied to prevent loss of synchronism of all the generators at a site, KEPCO Systems. (author). 4 refs., 8 figs., 4 tabs.
Power system small signal stability analysis and control
Mondal, Debasish; Sengupta, Aparajita
2014-01-01
Power System Small Signal Stability Analysis and Control presents a detailed analysis of the problem of severe outages due to the sustained growth of small signal oscillations in modern interconnected power systems. The ever-expanding nature of power systems and the rapid upgrade to smart grid technologies call for the implementation of robust and optimal controls. Power systems that are forced to operate close to their stability limit have resulted in the use of control devices by utility companies to improve the performance of the transmission system against commonly occurring power system
An optimal real-time controller for vertical plasma stabilization
Cruz, N; Coda, S; Duval, B P; Le, H B; Rodrigues, A P; Varandas, C A F; Correia, C M B A; Goncalves, B S
2014-01-01
Modern Tokamaks have evolved from the initial axisymmetric circular plasma shape to an elongated axisymmetric plasma shape that improves the energy confinement time and the triple product, which is a generally used figure of merit for the conditions needed for fusion reactor performance. However, the elongated plasma cross section introduces a vertical instability that demands a real-time feedback control loop to stabilize the plasma vertical position and velocity. At the Tokamak \\`a Configuration Variable (TCV) in-vessel poloidal field coils driven by fast switching power supplies are used to stabilize highly elongated plasmas. TCV plasma experiments have used a PID algorithm based controller to correct the plasma vertical position. In late 2013 experiments a new optimal real-time controller was tested improving the stability of the plasma. This contribution describes the new optimal real-time controller developed. The choice of the model that describes the plasma response to the actuators is discussed. The ...
Biomass Combustion Control and Stabilization Using Low-Cost Sensors
Ján Piteľ; Jana Mižáková; Alexander Hošovský
2013-01-01
The paper describes methods for biomass combustion process control and burning stabilization based on low-cost sensing of carbon monoxide emissions and oxygen concentration in the flue gas. The designed control system was tested on medium-scale biomass-fired boilers and some results are evaluated and presented in the paper.
Lam, Hak-Keung
2016-01-01
This book presents recent research on the stability analysis of polynomial-fuzzy-model-based control systems where the concept of partially/imperfectly matched premises and membership-function dependent analysis are considered. The membership-function-dependent analysis offers a new research direction for fuzzy-model-based control systems by taking into account the characteristic and information of the membership functions in the stability analysis. The book presents on a research level the most recent and advanced research results, promotes the research of polynomial-fuzzy-model-based control systems, and provides theoretical support and point a research direction to postgraduate students and fellow researchers. Each chapter provides numerical examples to verify the analysis results, demonstrate the effectiveness of the proposed polynomial fuzzy control schemes, and explain the design procedure. The book is comprehensively written enclosing detailed derivation steps and mathematical derivations also for read...
A novel single thruster control strategy for spacecraft attitude stabilization
Godard; Kumar, Krishna Dev; Zou, An-Min
2013-05-01
Feasibility of achieving three axis attitude stabilization using a single thruster is explored in this paper. Torques are generated using a thruster orientation mechanism with which the thrust vector can be tilted on a two axis gimbal. A robust nonlinear control scheme is developed based on the nonlinear kinematic and dynamic equations of motion of a rigid body spacecraft in the presence of gravity gradient torque and external disturbances. The spacecraft, controlled using the proposed concept, constitutes an underactuated system (a system with fewer independent control inputs than degrees of freedom) with nonlinear dynamics. Moreover, using thruster gimbal angles as control inputs make the system non-affine (control terms appear nonlinearly in the state equation). This necessitates the control algorithms to be developed based on nonlinear control theory since linear control methods are not directly applicable. The stability conditions for the spacecraft attitude motion for robustness against uncertainties and disturbances are derived to establish the regions of asymptotic 3-axis attitude stabilization. Several numerical simulations are presented to demonstrate the efficacy of the proposed controller and validate the theoretical results. The control algorithm is shown to compensate for time-varying external disturbances including solar radiation pressure, aerodynamic forces, and magnetic disturbances; and uncertainties in the spacecraft inertia parameters. The numerical results also establish the robustness of the proposed control scheme to negate disturbances caused by orbit eccentricity.
Nonlinear Output Feedback Control of Underwater Vehicle Propellers using Advance Speed Feedback
Fossen, T.I.; Blanke, M.
1999-01-01
More accurate propeller shaft speed controllers can be designed by using nonlinear control theory. In this paper, an output feedback controller reconstructing the advance speed (speed of water going into the propeller) from vehicle speed measurements is derived. For this purpose a three-state model...... of propeller shaft speed, forward (surge) speed of the vehicle and axial inlet flow of the propeller is applied. A nonlinear observer in combination with an output feedback integral controller are derived by applying Lyapunov stability theory and exponential stability is proven. The output feedback...... controller minimizes thruster losses due to variations in propeller axial inlet flow which is a major problem when applying conventional vehicle-propeller control systems. The proposed controller is simulated for an underwater vehicle equipped with a single propeller. From the simulations it can be concluded...
Scholbrock, A. K.; Fleming, P. A.; Fingersh, L. J.; Wright, A. D.; Schlipf, D.; Haizmann, F.; Belen, F.
2013-01-01
Wind turbines are complex, nonlinear, dynamic systems driven by aerodynamic, gravitational, centrifugal, and gyroscopic forces. The aerodynamics of wind turbines are nonlinear, unsteady, and complex. Turbine rotors are subjected to a chaotic three-dimensional (3-D) turbulent wind inflow field with imbedded coherent vortices that drive fatigue loads and reduce lifetime. In order to reduce cost of energy, future large multimegawatt turbines must be designed with lighter weight structures, using active controls to mitigate fatigue loads, maximize energy capture, and add active damping to maintain stability for these dynamically active structures operating in a complex environment. Researchers at the National Renewable Energy Laboratory (NREL) and University of Stuttgart are designing, implementing, and testing advanced feed-back and feed-forward controls in order to reduce the cost of energy for wind turbines.
An active interferometer-stabilization scheme with linear phase control
Vardhan Krishnamachari, Vishnu; Andresen, Esben Ravn; Potma, Eric Olaf
2006-01-01
We report a simple and robust computer-based active interferometer stabilization scheme which does not require modulation of the interfering beams and relies on an error signal which is linearly related to the optical path difference. In this setup, a non-collinearly propagating reference laser...... beam stabilizes the interference output of the laser light propagating collinearly through the interferometer. This stabilization scheme enables adjustable phase control with 20 ms switching times in the range from 0.02π radians to 6π radians at 632.8 nm....
Application of stability theory to laminar flow control
Hefner, J. N.; Bushnell, D. M.
1979-01-01
The paper summarizes the state-of-the-art for application of stability theory to laminar flow control using suction, wall temperature and/or favorable pressure gradient ('natural laminar flow'). Discussions include current LFC problem areas requiring stability analyses, methods of relating stability theory to transition with results from data and theory comparisons available thus far, and a summary of low disturbance data available for theory calibration on swept wings. Critical issues highlighted are problems peculiar to suction LFC on high performance transonic wings and application of the e-to-the-n-power method to both low and high speed flight data.
Adaptive Neural Network Controller for Thermogenerator Angular Velocity Stabilization System
Horvat, Krunoslav; Šoić, Ines; Kuljača, Ognjen
2013-01-01
The paper presents an analytical and simulation approach for the selection of activation functions for the class of neural network controllers for ship’s thermogenerator angular velocity stabilization system. Such systems can be found in many ships. A Lyapunov-like stability analysis is performed in order to obtain a weight update law. A number of simulations were performed to find the best activation function using integral error criteria and statistical T-tests.
Stability Analysis for Car Following Model Based on Control Theory
Stability analysis is one of the key issues in car-following theory. The stability analysis with Lyapunov function for the two velocity difference car-following model (for short, TVDM) is conducted and the control method to suppress traffic congestion is introduced. Numerical simulations are given and results are consistent with the theoretical analysis. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Stability of infinite-horizon optimal control with discounted cost
Postoyan, Romain; Busoniu, Lucian; Nesic, Dragan; Daafouz, Jamal
2014-01-01
We investigate the stability of general nonlinear discrete-time systems controlled by an optimal sequence of inputs that minimizes an infinite-horizon discounted cost. We first provide conditions under which a global asymptotic stability property is ensured for the corresponding undiscounted problem. We then show that this property is semiglobally and practically preserved in the discounted case, where the adjustable parameter is the discount factor. We then focus on a scenario where the stag...
Motion and Walking Stabilization of Humanoids Using Sensory Reflex Control
Jong-Wook Kim; Tin Trung Tran; Chien Van Dang; Bongsoon Kang
2016-01-01
Humanoid robots are versatile robot platforms that can carry out intelligent tasks and services for humans, including intimate interactions. For high mobility, a robust stabilization of motion including biped walking is crucial. This paper employs and elaborates on sensory reflex control to stabilize standing motion and biped walking using basic sensors such as an inertial measurement unit (IMU) and a force-sensing resistor (FSR). Specifically, normalized zero-moment points processed from FSR...
Optimal Sliding Mode Controllers for Attitude Stabilization of Flexible Spacecraft
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.
Adaptive Dynamic Programming for Control Algorithms and Stability
Zhang, Huaguang; Luo, Yanhong; Wang, Ding
2013-01-01
There are many methods of stable controller design for nonlinear systems. In seeking to go beyond the minimum requirement of stability, Adaptive Dynamic Programming for Control approaches the challenging topic of optimal control for nonlinear systems using the tools of adaptive dynamic programming (ADP). The range of systems treated is extensive; affine, switched, singularly perturbed and time-delay nonlinear systems are discussed as are the uses of neural networks and techniques of value and policy iteration. The text features three main aspects of ADP in which the methods proposed for stabilization and for tracking and games benefit from the incorporation of optimal control methods: • infinite-horizon control for which the difficulty of solving partial differential Hamilton–Jacobi–Bellman equations directly is overcome, and proof provided that the iterative value function updating sequence converges to the infimum of all the value functions obtained by admissible control law sequences; • finite-...
Eco-geomorphic controls on slope stability
Hales, T.; Ford, C.; Hwang, T.; Vose, J.; Band, L.
2009-04-01
Vegetation controls soil-mantled landscape evolution primarily through growth of roots into soil and rock. Root-soil interactions affect the spatial distribution and rate of shallow landsliding and other hillslope processes. Yet the distribution and tensile strength of roots depends on a number of geomorphically-influenced parameters, including soil moisture. Our field-based study investigated the effects of topography on root distributions, tensile strengths, and cohesion. Systematic differences in plant species distribution and soil properties are found in the hollow-nose topography of soil-mantled landscapes; with hollows containing thick colluvial soils and mesic tree species and noses containing thinner, more differentiated soils and more xeric species. We investigated whether these topographic variations in geomorphic and ecologic properties affected the spatial distribution of root cohesion by measuring the distribution and tensile strength of roots from soil pits dug downslope of fifteen individual trees in the Coweeta Hydrologic Laboratory, North Carolina. Our soil pits were located to capture variance in plant species (10 species total), topographic positions (nose, hollow), and sizes (a range of DBH between 5 cm and 60 cm). Root tensile strengths showed little variance with different species, but showed strong differences as a function of topography, with nose roots stronger than hollow roots. Similarly, within species, root cellulose content was systematically greater in trees on nose positions compared to those in hollows. For all species, roots were concentrated close to the soil surface (at least 70% of biomass occurred within 50 cm of the surface) and variations in this pattern were primarily a function of topographic position. Hollow roots were more evenly distributed in the soil column than those on noses, yet trees located on noses had higher mean root cohesion than those in hollows because of a higher root tensile force. These data provide an
Ervaringen met Advanced Cruise Control (ACC) in een korte praktijkproef.
Oei, H.-l.
2003-01-01
Experiences with Advanced Cruise Control in traffic; a limited experiment. Advanced Cruise Control (ACC) is an ordinary cruise control in which the desired speed is installed manually, but in which the headway time to the vehicle in front is also taken into account. If the headway time becomes less than the installed critical threshold value, the system brakes the vehicle gradually. If the vehicle in front is no longer there, or the headway time is greater than the threshold value, the instal...
Zhang, Jianling; An, Jinwen; Wang, Mina
2005-11-01
This paper describes the application and simulation of an adaptive fuzzy controller for a missile model. The fuzzy control system is tested using different values of fuzzy controller correctional factor on a nonlinear missile model. It is shown that the self-tuning fuzzy controller is well suited for controlling the pitch loop of the missile control system with air turbulence and parameter variety. The research shows that the Popov stability criterion could successfully guarantee the stability of the fuzzy system. It provides a good method for the design of missile control system. Simulation results suggest significant benefits from fuzzy logic in control task for missile pitch loop control.
Overview of advanced process control in welding within ERDA
The special kinds of demands placed on ERDA weapons and reactors require them to have very reliable welds. Process control is critical in achieving this reliability. ERDA has a number of advanced process control projects underway with much of the emphasis being on electron beam welding. These include projects on voltage measurement, beam-current control, beam focusing, beam spot tracking, spike suppression, and computer control. A general discussion of process control in welding is followed by specific examples of some of the advanced joining process control projects in ERDA
Fuzzy-like PD controller for spatial control of advanced heavy water reactor
Londhe, P.S., E-mail: pandurangl97@gmail.com [Research Scholar, SGGS Institute of Engineering and Technology, Vishnupuri, Nanded 431606 (India); Patre, B.M., E-mail: bmpatre@ieee.org [Department of Instrumentation Engineering, Shri Guru Gobind Singhji Institute of Engineering and Technology, Vishnupuri, Nanded 431 606 (India); Tiwari, A.P., E-mail: aptiwari@barc.gov.in [Reactor Control Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)
2014-07-01
Highlights: • Highly non-linear model of AHWR is used for spatial power control. • A simple fuzzy-like PD (FZ-PD) control structure with robust rule base is developed. • Robust rule structure reduces the difficulties in design and tuning of controller. • Proposed FZ-PD structure shows robust and better transient performance. • Proposed FZ-PD controller is able to suppress spatial oscillations in AHWR. - Abstract: Spatial oscillations in the neutron flux distribution due to xenon reactivity feedback requires stringent control in large nuclear reactors, like advanced heavy water reactor (AHWR). If the spatial oscillations in the power distribution are not controlled, power density and rate of change of power at some locations in the reactor core may exceed limits of fuel failure due to ‘flux tilting’. Further, situations such as on-line refueling might cause transient variations in flux-shape from the nominal flux-shape. For analysis and control of spatial oscillations in AHWR, it is necessary to design a suitable control strategy, which will stabilize these oscillations. In this paper, a simplified scheme to design a conventional fuzzy logic controller for spatial control of AHWR is presented. This scheme known as fuzzy-like proportional derivative (FZ-PD) controller, uses robust PD (proportional derivative) type rule base. Due to robust rule base structure, tuning of scaling factors is greatly reduced. The non-linear coupled core neutronics-thermal hydraulics model of AHWR considered here represented by 90 first order differential equations. Through the dynamic simulations, it is observed that the designed FZ-PD controller is able to suppress spatial oscillations developed in AHWR and its performance is found to be robust.
A switched system approach to stabilization f networked control systems
无
2006-01-01
A switched system approach is proposed to model networked control systems (NCSs) with communication constraints. This enables us to apply the rich theory of switched systems to analyzing such NCSs. Sufficient conditions are presented on the stabilization of NCSs. Stabilizing state/output feedback controllers can be constructed by using the feasible solutions of some linear matrix inequalities (LMIs). The merit of our proposed approach is that the behavior of the NCSs can be studied by considering switched system without augmenting the system. A simulation example is worked out to illustrate the effectiveness of the proposed approach.
Introduction to Computational Methods for Stability and Control (COMSAC)
Hall, Robert M.; Fremaux, C. Michael; Chambers, Joseph R.
2004-01-01
This Symposium is intended to bring together the often distinct cultures of the Stability and Control (S&C) community and the Computational Fluid Dynamics (CFD) community. The COMSAC program is itself a new effort by NASA Langley to accelerate the application of high end CFD methodologies to the demanding job of predicting stability and control characteristics of aircraft. This talk is intended to set the stage for needing a program like COMSAC. It is not intended to give details of the program itself. The topics include: 1) S&C Challenges; 2) Aero prediction methodology; 3) CFD applications; 4) NASA COMSAC planning; 5) Objectives of symposium; and 6) Closing remarks.
In this paper, a physical method to obtain control-oriented dynamical models of large scale cryogenic refrigerators is proposed, in order to synthesize model-based advanced control schemes. These schemes aim to replace classical user experience designed approaches usually based on many independent PI controllers. This is particularly useful in the case where cryoplants are submitted to large pulsed thermal loads, expected to take place in the cryogenic cooling systems of future fusion reactors such as the International Thermonuclear Experimental Reactor (ITER) or the Japan Torus-60 Super Advanced Fusion Experiment (JT-60SA). Advanced control schemes lead to a better perturbation immunity and rejection, to offer a safer utilization of cryoplants. The paper gives details on how basic components used in the field of large scale helium refrigeration (especially those present on the 400W @1.8K helium test facility at CEA-Grenoble) are modeled and assembled to obtain the complete dynamic description of controllable subsystems of the refrigerator (controllable subsystems are namely the Joule-Thompson Cycle, the Brayton Cycle, the Liquid Nitrogen Precooling Unit and the Warm Compression Station). The complete 400W @1.8K (in the 400W @4.4K configuration) helium test facility model is then validated against experimental data and the optimal control of both the Joule-Thompson valve and the turbine valve is proposed, to stabilize the plant under highly variable thermals loads. This work is partially supported through the European Fusion Development Agreement (EFDA) Goal Oriented Training Program, task agreement WP10-GOT-GIRO
Stability Boundaries for Offshore Wind Park Distributed Voltage Control
Gryning, Mikkel P.S.; Wu, Qiuwei; Kocewiak, Lukasz;
2016-01-01
In order to identify mechanisms causing slow reactive power oscillations observed in an existing offshore wind power plant, and be able to avoid similar events in the future, voltage control is studied in this paper for a plant with a static synchronous compensator, type-4 wind turbines and a park...... pilot control. Using data from the actual wind power plant, all stabilizing subsystem voltage proportional-integral controller parameters are first characterized based on their Hurwitz signature. Inner loop current control is then designed using Internal Mode Control principles, and guidelines for feed...
Mechanics and model-based control of advanced engineering systems
Irschik, Hans; Krommer, Michael
2014-01-01
Mechanics and Model-Based Control of Advanced Engineering Systems collects 32 contributions presented at the International Workshop on Advanced Dynamics and Model Based Control of Structures and Machines, which took place in St. Petersburg, Russia in July 2012. The workshop continued a series of international workshops, which started with a Japan-Austria Joint Workshop on Mechanics and Model Based Control of Smart Materials and Structures and a Russia-Austria Joint Workshop on Advanced Dynamics and Model Based Control of Structures and Machines. In the present volume, 10 full-length papers based on presentations from Russia, 9 from Austria, 8 from Japan, 3 from Italy, one from Germany and one from Taiwan are included, which represent the state of the art in the field of mechanics and model based control, with particular emphasis on the application of advanced structures and machines.
Barret, C.
1995-01-01
The Marshall Space Flight Center has a rich heritage of launch vehicles that have used aerodynamic surfaces for flight stability such as the Saturn vehicles and flight control such as on the Redstone. Recently, due to aft center-of-gravity locations on launch vehicles currently being studied, the need has arisen for the vehicle control augmentation that is provided by these flight controls. Aerodynamic flight control can also reduce engine gimbaling requirements, provide actuator failure protection, enhance crew safety, and increase vehicle reliability, and payload capability. In the Saturn era, NASA went to the Moon with 300 sq ft of aerodynamic surfaces on the Saturn V. Since those days, the wealth of smart materials and advanced composites that have been developed allow for the design of very lightweight, strong, and innovative launch vehicle flight control surfaces. This paper presents an overview of the advanced composites and smart materials that are directly applicable to launch vehicle control surfaces.
Advanced topics in control and estimation of state-multiplicative noisy systems
Gershon, Eli
2013-01-01
Advanced Topics in Control and Estimation of State-Multiplicative Noisy Systems begins with an introduction and extensive literature survey. The text proceeds to cover solutions of measurement-feedback control and state problems and the formulation of the Bounded Real Lemma for both continuous- and discrete-time systems. The continuous-time reduced-order and stochastic-tracking control problems for delayed systems are then treated. Ideas of nonlinear stability are introduced for infinite-horizon systems, again, in both the continuous- and discrete-time cases. The reader is introduced to six practical examples of noisy state-multiplicative control and filtering associated with various fields of control engineering. The book is rounded out by a three-part appendix containing stochastic tools necessary for a proper appreciation of the text: a basic introduction to nonlinear stochastic differential equations and aspects of switched systems and peak to peak optimal control and filtering. Advanced Topics in Contr...
Global MHD Mode Stabilization and Control for Tokamak Disruption Avoidance
Sabbagh, S. A.; Berkery, J. W.; Bialek, J. M.; Hanson, J. M.; Park, Y. S.; Bell, R. E.; Gates, D. A.; Gerhardt, S. P.; Goumiri, I.; Grierson, B.; Holcomb, C.
2015-11-01
The near-complete elimination of plasma disruptions in fusion-producing tokamaks is the present ``grand challenge'' for stability research. Meeting this goal requires multiple approaches, important components of which are prediction, stabilization, and control of global MHD instabilities. Research on NSTX and its upgrade is synergizing these elements to make quantified progress on this challenge. Initial results from disruption characterization and prediction analyses describe physical disruption event chains in NSTX. Analysis of NSTX and DIII-D experiments show that stabilization of global modes is dominated by precession drift and bounce orbit resonances respectively. Stability therefore depends on the plasma rotation profile. A model-based rotation profile controller for NSTX-U using both neutral beams and neoclassical toroidal viscosity is shown in simulations to evolve profiles away from unstable states. Active RWM control is addressed using dual field component sensor feedback and a model-based RWM state-space controller. Comparison of measurements and synthetic diagnostics is examined for off-normal event handling. A planned 3D coil system upgrade can allow RWM control close to the ideal n = 1 with-wall limit. Supported by US DOE Contracts DE-FG02-99ER54524 and DE-AC02-09CH11466.
Strong stabilization servo controller with optimization of performance criteria.
Sarjaš, Andrej; Svečko, Rajko; Chowdhury, Amor
2011-07-01
Synthesis of a simple robust controller with a pole placement technique and a H(∞) metrics is the method used for control of a servo mechanism with BLDC and BDC electric motors. The method includes solving a polynomial equation on the basis of the chosen characteristic polynomial using the Manabe standard polynomial form and parametric solutions. Parametric solutions are introduced directly into the structure of the servo controller. On the basis of the chosen parametric solutions the robustness of a closed-loop system is assessed through uncertainty models and assessment of the norm ‖•‖(∞). The design procedure and the optimization are performed with a genetic algorithm differential evolution - DE. The DE optimization method determines a suboptimal solution throughout the optimization on the basis of a spectrally square polynomial and Šiljak's absolute stability test. The stability of the designed controller during the optimization is being checked with Lipatov's stability condition. Both utilized approaches: Šiljak's test and Lipatov's condition, check the robustness and stability characteristics on the basis of the polynomial's coefficients, and are very convenient for automated design of closed-loop control and for application in optimization algorithms such as DE. PMID:21501837
EFFECT OF PROFILES AND SHAPE ON IDEAL STABILITY OF ADVANCED TOKAMAK EQUILIBRIA
MAKOWSKI,MA; CASPER,TA; FERRON,JR; TAYLOR,TS; TURNBULL,AD
2003-08-01
OAK-B135 The pressure profile and plasma shape, parameterized by elongation ({kappa}), triangularity ({delta}), and squareness ({zeta}), strongly influence stability. In this study, ideal stability of single null and symmetric, double-null, advanced tokamak (AT) configurations is examined. All the various shapes are bounded by a common envelope and can be realized in the DIII-D tokamak. The calculated AT equilibria are characterized by P{sub 0}/
{approx} 2.0-4.5, weak negative central shear, high q{sub min} (> 2.0), high bootstrap fraction, an H-mode pedestal, and varying shape parameters. The pressure profile is modeled by various polynomials together with a hyperbolic tangent pedestal, consistent with experimental observations. Stability is calculated with the DCON code and the resulting stability boundary is corroborated by GATO runs.
Effect of Profiles and Space on Ideal Stability of Advanced Tokamak Equilibria
Makowski, M A; Casper, T A; Ferron, J R; Taylor, T S; Turnbull, A D
2003-07-07
The pressure profile and plasma shape, parameterized by elongation ({kappa}), triangularity ({delta}), and squareness ({zeta}), strongly influence stability. In this study, ideal stability of single null and symmetric, double-null, advanced tokamak (AT) configurations is examined. All the various shapes are bounded by a common envelope and can be realized in the DIII-D tokamak. The calculated AT equilibria are characterized by P{sub 0}/{l_angle}P{r_brace} {approx} 2.0-4.5, weak negative central shear, high q{sub min} (>2.0), high bootstrap fraction, an H-mode pedestal, and varying shape parameters. The pressure profile is modeled by various polynomials together with a hyperbolic tangent pedestal, consistent with experimental observations. Stability is calculated with the DCON code and the resulting stability boundary is corroborated by GATO runs.
Project T.E.A.M. (Technical Education Advancement Modules). Advanced Statistical Process Control.
Dunlap, Dale
This instructional guide, one of a series developed by the Technical Education Advancement Modules (TEAM) project, is a 20-hour advanced statistical process control (SPC) and quality improvement course designed to develop the following competencies: (1) understanding quality systems; (2) knowing the process; (3) solving quality problems; and (4)…
Model-free adaptive control of advanced power plants
Cheng, George Shu-Xing; Mulkey, Steven L.; Wang, Qiang
2015-08-18
A novel 3-Input-3-Output (3.times.3) Model-Free Adaptive (MFA) controller with a set of artificial neural networks as part of the controller is introduced. A 3.times.3 MFA control system using the inventive 3.times.3 MFA controller is described to control key process variables including Power, Steam Throttle Pressure, and Steam Temperature of boiler-turbine-generator (BTG) units in conventional and advanced power plants. Those advanced power plants may comprise Once-Through Supercritical (OTSC) Boilers, Circulating Fluidized-Bed (CFB) Boilers, and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.
Advanced Combustion and Emission Control Technical Team Roadmap
None
2013-06-01
The Advanced Combustion and Emission Control (ACEC) Technical Team is focused on removing technical barriers to the commercialization of advanced, high-efficiency, emission-compliant internal combustion (IC) engines for light-duty vehicle powertrains (i.e., passenger car, minivan, SUV, and pickup trucks).
Issues on stability of ADP feedback controllers for dynamical systems.
Balakrishnan, S N; Ding, Jie; Lewis, Frank L
2008-08-01
This paper traces the development of neural-network (NN)-based feedback controllers that are derived from the principle of adaptive/approximate dynamic programming (ADP) and discusses their closed-loop stability. Different versions of NN structures in the literature, which embed mathematical mappings related to solutions of the ADP-formulated problems called "adaptive critics" or "action-critic" networks, are discussed. Distinction between the two classes of ADP applications is pointed out. Furthermore, papers in "model-free" development and model-based neurocontrollers are reviewed in terms of their contributions to stability issues. Recent literature suggests that work in ADP-based feedback controllers with assured stability is growing in diverse forms. PMID:18632377
Power System Stability Enhancement Using Unified Power Flow Controller
Prechanon Kumkratug
2010-01-01
Full Text Available Problem statement: The enhancement of transient stability of the power system is one of the most challenging research areas in power engineer. Approach: This study presents the method to enhance transient stability of power system by Unified Power Flow Controller (UPFC. The mathematical model of power system equipped with a UPFC is systematically derived. The parameters of UPFC are modeled into power flow equation and thus it is used to determine control strategy. The swing curves of the three phase faulted power system without and with a UPFC are tested and compared in various cases. Results: The swing curve of system without a UPFC gets increases monotonically and thus the system can be considered as unstable whereas the swing curves of system with a UPFC can return to stable equilibrium point. Conclusion: From the simulation results, the UPFC can enhance transient stability of power system.
Gait Planning and Stability Control of a Quadruped Robot
Li, Junmin; Wang, Jinge; Yang, Simon X.; Zhou, Kedong; Tang, Huijuan
2016-01-01
In order to realize smooth gait planning and stability control of a quadruped robot, a new controller algorithm based on CPG-ZMP (central pattern generator-zero moment point) is put forward in this paper. To generate smooth gait and shorten the adjusting time of the model oscillation system, a new CPG model controller and its gait switching strategy based on Wilson-Cowan model are presented in the paper. The control signals of knee-hip joints are obtained by the improved multi-DOF reduced order control theory. To realize stability control, the adaptive speed adjustment and gait switch are completed by the real-time computing of ZMP. Experiment results show that the quadruped robot's gaits are efficiently generated and the gait switch is smooth in the CPG control algorithm. Meanwhile, the stability of robot's movement is improved greatly with the CPG-ZMP algorithm. The algorithm in this paper has good practicability, which lays a foundation for the production of the robot prototype. PMID:27143959
Motion control in advanced driving simulators
Elloumi, Hatem
2006-01-01
Driving simulators are advanced devices composed of four components: a virtual scene projected on a wide screen to imitate the road and the traffic, an audio system to play the driving sounds (horn, squeal of brakes, etc.), a car cockpit (including a real dashboard, the pedals and the seat of the driver) to copy the body position and the interaction of the driver with a real vehicle and finally a robot carrying the car cockpit to provide its motion. While the first three components could be c...
Advanced dc-Traction-Motor Control System
Vittone, O.
1985-01-01
Motor-control concept for battery-powered vehicles includes stateof-the-art power-transistor switching and separate excitation of motor windings in traction and regenerative braking. Switching transistors and other components of power-conditioning subsystem operate under control of computer that coordinates traction, braking, and protective functions.
Hakim, Lukmanul; Kubokawa, Junji; Yorino, Naoto; Zoka, Yoshifumi; Sasaki, Yutaka
Advancements have been made towards inclusion of both static and dynamic security into transfer capability calculation. However, to the authors' knowledge, work on considering corrective controls into the calculation has not been reported yet. Therefore, we propose a Total Transfer Capability (TTC) assessment considering transient stability corrective controls. The method is based on the Newton interior point method for nonlinear programming and transfer capability is approached as a maximization of power transfer with both static and transient stability constraints are incorporated into our Transient Stability Constrained Optimal Power Flow (TSCOPF) formulation. An interconnected power system is simulated to be subjected to a severe unbalanced 3-phase 4-line to ground fault and following the fault, generator and load are shed in a pre-defined sequence to mimic actual corrective controls. In a deregulated electricity market, both generator companies and large load customers are encouraged to actively participate in maintaining power system stability as corrective controls upon agreement of compensation for being shed following a disturbance. Implementation of this proposal on the actual power system operation should be carried out through combining it with the existing transient stabilization controller system. Utilization of these corrective controls results in increasing TTC as suggested in our numerical simulation. As Lagrange multipliers can also describe sensitivity of both inequality and equality constraints to the objective function, then selection of which generator or load to be shed can be carried out on the basis of values of Lagrange multipliers of its respective generator's rotor angle stability and active power balance equation. Hence, the proposal in this paper can be utilized by system operator to assess the maximum TTC for specific loads and network conditions.
Stability Analysis and Design of Impulsive Control Lorenz Systems Family
Lorenz systems family unifying Lorenz system, Chen system and Lue system is a typical chaotic family. In this paper, we consider impulsive control Lorenz chaotic systems family with time-varying impulse intervals. By establishing an effective tool of a set of inequalities, we analyze the asymptotic stability of impulsive control Lorenz systems family and obtain some new less conservative conditions. Based on the stability analysis, we design a novel impulsive controller with time-varying impulse intervals. Illustrative examples are provided to show the feasibility and effectiveness of our method. The obtained results not only can be used to design impulsive control for Lorenz systems family, but also can be extended to other chaotic systems. (general)
Stability Analysis and Design of Impulsive Control Lorenz Systems Family
YU Yong-Bin; ZHANG Hong-Bin; ZHANG Feng-Li; YU Jue-Bang; LIAO Xiao-Feng
2009-01-01
Lorenz systems family unifying Lorenz system, Chen system and Lu system is a typical chaotic family.In this paper, we consider impulsive control Lorenz chaotic systems family with time-varying impulse intervals. By establishing an effective tool of a set of inequalities, we analyze the asymptotic stability of impulsive control Lorenz systems family and obtain some new less conservative conditions. Based on the stability analysis, we design a novel impulsive controller with time-varying impulse intervals. Illustrative examples are provided to show the feasibility and effectiveness of our method. The obtained results not only can be used to design impulsive control for Lorenz systems family, but also can be extended to other chaotic systems.
The longitudinal controls fixed static stability of tailless aircraft
de Castro, Helena V.
2000-01-01
This paper describes the development of a simple theory of the longitudinal controls fixed static stability of tailless aeroplanes. The classical theory, as developed for the conventional aircraft, is modified to accommodate the particular features of the tailless aeroplanes. The theory was then applied to a particular blended-wing-body tailless civil transport aircraft, BWB-98.
Robust stability in constrained predictive control through the Youla parameterisations
Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad
2011-01-01
In this article we take advantage of the primary and dual Youla parameterisations to set up a soft constrained model predictive control (MPC) scheme. In this framework it is possible to guarantee stability in face of norm-bounded uncertainties. Under special conditions guarantees are also given f...
Stability and servo-control of the crystal pulling process
The paper analyzes why the crystal pulling process needs servo-control, and how it can be implemented. Special emphasis is put on the fundamental question of inherent stability, and how to interpret the signal from a balance when the weighing method is used for cystal diameter detection. 15 refs., 13 figs
Stabilizing the Richardson eigenvector algorithm by controlling chaos
By viewing the operations of the Richardson purification algorithm as a discrete time dynamical process, we propose a method to overcome the instability of this eigenvector algorithm by controlling chaos. We present theoretical analysis and numerical results on the behavior and performance of the stabilized algorithm. copyright 1997 American Institute of Physics
Generic Model Predictive Control Framework for Advanced Driver Assistance Systems
Wang, M.
2014-01-01
This thesis deals with a model predictive control framework for control design of Advanced Driver Assistance Systems, where car-following tasks are under control. The framework is applied to design several autonomous and cooperative controllers and to examine the controller properties at the microscopic level and the resulting traffic flow characteristics at the macroscopic level. The results give new insights into impacts of ADAS on traffic flow characteristics.
Stability and control of VTOL capable airships in hovering flight
Curtiss, H. C., Jr.; Sumantran, V.
1985-01-01
The stability and control characteristics of an airship equipped with lifting rotors to provide a modest VTOL capability are discussed. The rotors are used for control and maneuvering in near-hovering flight. Configurations with two, three, and four lifting rotors are examined and compared with respect to control capabilities and dynamic response characteristics. Linearized models of the dynamics are employed for this study. A new approach to the prediction of rotor derivatives for operation near zero thrust in hover is presented. It is found that all three configurations have similar control and response characteristics. The responses are characterized by long time constants and low levels of angular damping.
Neural Network Predictive Control Based Power System Stabilizer
Ali Mohamed Yousef
2012-01-01
The present study investigates the power system stabilizer based on neural predictive control for improving power system dynamic performance over a wide range of operating conditions. In this study a design and application of the Neural Network Model Predictive Controller (NN-MPC) on a simple power system composed of a synchronous generator connected to an infinite bus through a transmission line is proposed. The synchronous machine is represented in detail, taking into account the effect of ...
Stability and control of wind farms in power systems
Jauch, Clemens
2006-01-01
The Ph.D. project ‘Stability and Control of Wind Farms in Power Systems’ deals with some selected problems related to wind power in power systems. With increasing wind power penetration, wind turbines substitute the power production of conventional powerplants. Therefore, wind turbines also have to take over the power system stabilisation and control tasks, that were traditionally carried out by conventional power plants. Out of the many aspects related to this problem, this project focuses o...
Distributed Model Predictive Control with Suboptimality and Stability Guarantees
Giselsson, Pontus; Rantzer, Anders
2010-01-01
Theory for Distributed Model Predictive Control (DMPC) is developed based on dual decomposition of the convex optimization problem that is solved in each time sample. The process to be controlled is an interconnection of several subsystems, where each subsystem corresponds to a node in a graph. We present a stopping criterion for the DMPC scheme that can be locally verified by each node and that guarantees closed loop suboptimality above a pre-specified level and asymptotic stability of the i...
Clay, D.T.; Frederickson, J.O.; Andrews, J.R. [James River Corp., Berlin, NH (United States). Engineering Dept.
1995-12-31
Black liquor firing control strategies strive to buffer chemical recovery units (CRU) from changes in kraft pulp mill process. The importance of firing control strategy has increased recently with the trend to link concentrators directly to CRU liquor headers to ensure minimal liquor storage. Four control strategies were evaluated: (1) black liquor nozzle pressure, (2) black liquor volumetric flow, (3) black liquor solids mass flow, and (4) energy flow control. The variation between the base case and the four different control strategies was evaluated by changes in six process parameters, i.e., pressure, velocity, solids mass flow, energy released, droplet diameter, and droplet evaporative load. Results indicated that for non-fouling units, the energy release strategy provided the best stability. For fouling units, the choice was less obvious; none of the evaluated control strategies ranked consistently best. Liquor header (nozzle) pressure control proved to be least desirable. 10 refs., 8 figs., 4 tabs.
Advanced conduction angle control of permanent magnet brushless motor drives
Gan, J.; Chan, CC; Jiang, JZ; Chau, KT
1998-01-01
A novel advanced conduction angle control scheme for permanent magnet brushless motor drives is presented in this paper. The originality of this scheme is to employ the transformer EMF in stator windings to counteract the rotational EMF by controlling the advanced conduction angle when the motor drive operates above the base speed. Hence the constant-power operation region can be extended considerably, even though the current regulator is in saturation. The attractive feature of the proposed ...
Advanced Control Strategies for Mobile Hydraulic Applications
Cristofori, Davide
2013-01-01
Mobile hydraulic machines are affected by numerous undesired dynamics, mainly discontinuous motion and vibrations. Over the years, many methods have been developed to limit the extent of those undesired dynamics and improve controllability and safety of operation of the machine. However, in most of the cases, today's methods do not significantly differ from those developed in a time when electronic controllers were slower and less reliable than they are today. This dissertation addresses t...
Cooperative research for human factors review of advanced control rooms
This project has been performed as cooperative research between KAERI and USNRC. Human factors issues related to soft controls, which is one of key features of advanced HSI, are identified in this project. The issues are analyzed for the evaluation approaches in either experimental or analytical ways. Also, issues requiring additional researches for the evaluation of advanced HSI are identified in the areas of advanced information systems design, computer-based procedure systems, soft controls, human systems interface and plant modernization process, and maintainability of digital systems. The issues are analyzed to discriminate the urgency of researches on it to high, medium, and low levels in consideration of advanced HSI development status in Korea, and some of the issues that can be handled by experimental researches are identified. Additionally, an experimental study is performed to compare operator's performance on human error detection in advanced control rooms vs. in conventional control rooms. It is found that advanced control rooms have several design characteristics hindering operator's error detection performance compared to conventional control rooms
Stability Control of an Autonomous Quadcopter through PID Control Law
Nicolas Ives Roque Pacheco
2015-05-01
Full Text Available In the recent years the world has seen a astonishing ascendance of non tripulated vehicles, and among these is the quadrotors aircrafts or quadcopters. These types of aircraft have been of particular interest due to its easy maneuverability in closed and open spaces and somewhat simplified dynamics. In these paper is presented an first attempt in the built model, to control the 4 DOF(Degrees of freedom of an soon to be autonomous quadcopter through PID law in an controlled environment.
Transient stability improvement by nonlinear controllers based on tracking
Ramirez, Juan M. [Centro de Investigacion y Estudios Avanzados, Guadalajara, Mexico. Av. Cientifica 1145. Col. El Bajio. Zapopan, Jal. 45015 (Mexico); Arroyave, Felipe Valencia; Correa Gutierrez, Rosa Elvira [Universidad Nacional de Colombia, Sede Medellin. Facultad de Minas, Escuela de Mecatronica (Colombia)
2011-02-15
This paper deals with the control problem in multi-machine electric power systems, which represent complex great scale nonlinear systems. Thus, the controller design is a challenging problem. These systems are subjected to different perturbations, such as short circuits, connection and/or disconnection of loads, lines, or generators. Then, the utilization of controllers which guarantee good performance under those perturbations is required in order to provide electrical energy to the loads with admissible stability margins. The proposed controllers are based on a systematic strategy, which calculate nonlinear controllers for generating units in a power plant, both for voltage and velocity regulation. The formulation allows designing controllers in a multi-machine power system without intricate calculations. Results on a power system of the open research indicate the proposition's suitability. The problem is formulated as a tracking problem. The designed controllers may be implemented in any electric power system. (author)
Control of Smart Building Using Advanced SCADA
Samuel, Vivin Thomas
For complete control of the building, a proper SCADA implementation and the optimization strategy has to be build. For better communication and efficiency a proper channel between the Communication protocol and SCADA has to be designed. This paper concentrate mainly between the communication protocol, and the SCADA implementation, for a better optimization and energy savings is derived to large scale industrial buildings. The communication channel used in order to completely control the building remotely from a distant place. For an efficient result we consider the temperature values and the power ratings of the equipment so that while controlling the equipment, we are setting a threshold values for FDD technique implementation. Building management system became a vital source for any building to maintain it and for safety purpose. Smart buildings, refers to various distinct features, where the complete automation system, office building controls, data center controls. ELC's are used to communicate the load values of the building to the remote server from a far location with the help of an Ethernet communication channel. Based on the demand fluctuation and the peak voltage, the loads operate differently increasing the consumption rate thus results in the increase in the annual consumption bill. In modern days, saving energy and reducing the consumption bill is most essential for any building for a better and long operation. The equipment - monitored regularly and optimization strategy is implemented for cost reduction automation system. Thus results in the reduction of annual cost reduction and load lifetime increase.
Advanced mobile networking, sensing, and controls.
Feddema, John Todd; Kilman, Dominique Marie; Byrne, Raymond Harry; Young, Joseph G.; Lewis, Christopher L.; Van Leeuwen, Brian P.; Robinett, Rush D. III; Harrington, John J.
2005-03-01
This report describes an integrated approach for designing communication, sensing, and control systems for mobile distributed systems. Graph theoretic methods are used to analyze the input/output reachability and structural controllability and observability of a decentralized system. Embedded in each network node, this analysis will automatically reconfigure an ad hoc communication network for the sensing and control task at hand. The graph analysis can also be used to create the optimal communication flow control based upon the spatial distribution of the network nodes. Edge coloring algorithms tell us that the minimum number of time slots in a planar network is equal to either the maximum number of adjacent nodes (or degree) of the undirected graph plus some small number. Therefore, the more spread out that the nodes are, the fewer number of time slots are needed for communication, and the smaller the latency between nodes. In a coupled system, this results in a more responsive sensor network and control system. Network protocols are developed to propagate this information, and distributed algorithms are developed to automatically adjust the number of time slots available for communication. These protocols and algorithms must be extremely efficient and only updated as network nodes move. In addition, queuing theory is used to analyze the delay characteristics of Carrier Sense Multiple Access (CSMA) networks. This report documents the analysis, simulation, and implementation of these algorithms performed under this Laboratory Directed Research and Development (LDRD) effort.
The electric power engineering handbook power system stability and control
Grisby, Leonard L
2012-01-01
With contributions from worldwide leaders in the field, Power System Stability and Control, Third Edition (part of the five-volume set, The Electric Power Engineering Handbook) updates coverage of recent developments and rapid technological growth in essential aspects of power systems. Edited by L.L. Grigsby, a respected and accomplished authority in power engineering, and section editors Miroslav Begovic, Prabha Kundur, and Bruce Wollenberg, this reference presents substantially new and revised content. Topics covered include: * Power System Protection * Power System Dynamics and Stability *
Robust stability analysis for uncertain sampled-data control systems
This paper investigates robust stability (RS) of uncertain sampled-data (SD) control systems with generalized sampled-data hold functions (GSHF). A new sufficient condition for robust stability of such systems is developed. Unlike that of most of the previous works, it directly uses the data of tile continuous-time plant and therefore it is less conservative. The condition is expressed in terms of the spectral radius of a certain matrix and is shown to l)e a uni modal function of a free parameter. Thus standard one-dimensional optimization algorithm can be used to perform the proposed test
Stability of periodic orbits controlled by time-delay feedback
Bleich, M E; Bleich, Michael E; Socolar, Joshua E S
1995-01-01
Extended time-delay auto-synchronization (ETDAS) is a promising technique for stabilizing unstable periodic orbits in low-dimensional dynamical systems. The technique involves continuous feedback of signals delayed by multiples of the orbit's period in a manner that is especially well-suited for fast systems and optical implementation. We show how to analyze the stability of a given implementation of ETDAS without explicit integration of time-delay equations. To illustrate the method and point out some nontrivial features of ETDAS, we obtain the domain of control for a period-one orbit of the driven, damped pendulum.
Saving Building Energy through Advanced Control Strategies
Stephen Treado
2013-09-01
Full Text Available This article presents an analysis of the relationship between building energy usage and building control system operation and performance. A method is presented for estimating the energy saving potential of improvements in building and control system operation, including the relative impact of recommssioning and hardware and software upgrades, based on a subjective assessment of the level of energy efficient design and the energy usage of the building relative to similar buildings as indicated by the Energy Utilization Index for the building. The method introduces a Building Design Index and a Building Operating Index to evaluate building energy performance versus similar buildings, and uses these indices to estimate potential savings and effectiveness of control system improvements.
Advanced Stellar Compass, CHAMP, Interface Control Document
Madsen, Peter Buch; Jørgensen, John Leif; Betto, Maurizio;
1999-01-01
The German government research establishment "GeoForschungsZentrum" developed under a contract to the German government a microsatellite named "Champ". The Space Instrumentation Group has made a Interface Control Document for the CHAMP, witch describes the Star Imager, the electrical interface, t...... mechanical interface and the TC/TM protocols for the communication between the Star Tracker and the OBDH.......The German government research establishment "GeoForschungsZentrum" developed under a contract to the German government a microsatellite named "Champ". The Space Instrumentation Group has made a Interface Control Document for the CHAMP, witch describes the Star Imager, the electrical interface, the...
Effects of saccadic eye movements on postural control stabilization
Sérgio Tosi Rodrigues
2013-09-01
Full Text Available Several structures of the central nervous system share involvement in both ocular and postural control, but the visual mechanisms in postural control are still unclear. There are discrepant evidences on whether saccades would improve or deteriorate stabilization of posture. The purpose of this study was to determine the influence of saccadic eye movements on postural control while standing in different basis of support. Twelve young adults stood upright in wide and narrow stances while performing fixation and saccades of low and high frequencies. Body sway was attenuated during saccades. Trunk anterior-posterior sway and trunk total displacement decreased during saccades compared to fixation; higher sway mean frequency in anterior-posterior direction during saccades was observed. Body sway was reduced in wide compared to narrow stance during high frequency saccades. These results indicate that eye movement improves postural stabilization and this effect is stronger in combination of wide stance-high frequency gaze condition.
Motion and Walking Stabilization of Humanoids Using Sensory Reflex Control
Jong-Wook Kim
2016-04-01
Full Text Available Humanoid robots are versatile robot platforms that can carry out intelligent tasks and services for humans, including intimate interactions. For high mobility, a robust stabilization of motion including biped walking is crucial. This paper employs and elaborates on sensory reflex control to stabilize standing motion and biped walking using basic sensors such as an inertial measurement unit (IMU and a force-sensing resistor (FSR. Specifically, normalized zero-moment points processed from FSR data are used in the reflexive control of a simple motion of swinging the whole body while standing, and the measured inclination angle of the trunk, filtered from IMU data, is used for biped walking on a sloped floor. The proposed control scheme is validated through experiments with the commercial humanoid robot, ROBOTIS-OP.
Study on modeling of vehicle dynamic stability and control technique
GAO Yun-ting; LI Pan-feng
2012-01-01
In order to solve the problem of enhancing the vehicle driving stability and safety,which has been the hot question researched by scientific and engineering in the vehicle industry,the new control method was investigated.After the analysis of tire moving characteristics and the vehicle stress analysis,the tire model based on the extension pacejka magic formula which combined longitudinal motion and lateral motion was developed and a nonlinear vehicle dynamical stability model with seven freedoms was made.A new model reference adaptive control project which made the slip angle and yaw rate of vehicle body as the output and feedback variable in adjusting the torque of vehicle body to control the vehicle stability was designed.A simulation model was also built in Matlab/Simulink to evaluate this control project.It was made up of many mathematical subsystem models mainly including the tire model module,the yaw moment calculation module,the center of mass parameter calculation module,tire parameter calculation module of multiple and so forth.The severe lane change simulation result shows that this vehicle model and the model reference adaptive control method have an excellent performance.
Human factors survey of advanced instrumentation and controls
A survey oriented towards identifying the human factors issues in regard to the use of advanced instrumentation and controls (I ampersand C) in the nuclear industry was conducted. A number of United States (US) and Canadian nuclear vendors and utilities were participants in the survey. Human factors items, subsumed under the categories of computer-generated displays (CGD), controls, organizational support, training, and related topics, were discussed. The survey found the industry to be concerned about the human factors issues related to the implementation of advanced I ampersand C. Fifteen potential human factors problems were identified. They include: the need for an advanced I ampersand C guideline equivalent to NUREG-0700; a role change in the control room from operator to supervisor; information overload; adequacy of existing training technology for advanced I ampersand C; and operator acceptance and trust. 11 refs., 1 tab
Human factors survey of advanced instrumentation and controls
Carter, R.J.
1989-01-01
A survey oriented towards identifying the human factors issues in regard to the use of advanced instrumentation and controls (I C) in the nuclear industry was conducted. A number of United States (US) and Canadian nuclear vendors and utilities were participants in the survey. Human factors items, subsumed under the categories of computer-generated displays (CGD), controls, organizational support, training, and related topics, were discussed. The survey found the industry to be concerned about the human factors issues related to the implementation of advanced I C. Fifteen potential human factors problems were identified. They include: the need for an advanced I C guideline equivalent to NUREG-0700; a role change in the control room from operator to supervisor; information overload; adequacy of existing training technology for advanced I C; and operator acceptance and trust. 11 refs., 1 tab.
Advanced Control Techniques for WEC Wave Dragon
Tedd, James; Kofoed, Jens Peter; Jasinski, M.; Morris, A.; Friis-Madsen, E.; Wisniewski, Rafal; Bendtsen, Jan Dimon
2007-01-01
This paper presents the ongoing work on control of the Wave Dragon wave energy converter. Research is being conducted in and between several centers across Europe. This is building upon the knowledge gained in the prototype project, and will enable much better performance of the future deployment...
Simulation of advanced concepts for damage control
Gillis, M.P.W.; Keijer, W.; Smit, C.S.; Wolff, P.A.
2003-01-01
Damage control on board navy ships requires a lot of manpower. On a frigate-sized ship of the Royal Netherlands Navy, up to ninety people can be involved in tasks like fire fighting, battle damage repair and treatment of casualties. In present times this is no longer attainable or affordable. To red
Elements of an advanced integrated operator control station
One of the critical determinants of performance for any remotely operated maintenance system is the compatibility achieved between elements of the man/machine interface (e.g., master manipulator controller, controls, displays) and the human operator. In the Remote Control Engineering task of the Consolidated Fuel Reprocessing Program, considerable attention has been devoted to optimizing the man/machine interface of the operator control station. This system must be considered an integral element of the overall maintenance work system which includes transporters, manipulators, remote viewing, and other parts. The control station must reflect the integration of the operator team, control/ display panels, manipulator master controllers, and remote viewing monitors. Human factors principles and experimentation have been used in the development of an advanced integrated operator control station designed for the advance servomanipulator. Key features of this next-generation design are summarized in this presentation
Elements of an advanced integrated operator control station
One of the critical determinants of peformance for any remotely operated maintenance system is the compatibility achieved between elements of the man/machine interface (e.g., master manipulator controller, controls, displays, etc.) and the human operator. In the Remote Control Engineering task of the Consolidated Fuel Reprocessing Program, considerable attention has been devoted to optimizing the man/machine interface of the operator control station. This system must be considered an integral element of the overall maintenance work system which includes transporters, manipulators, remote viewing, and other parts. The control station must reflect the integration of the operator team, control/display panels, manipulator master controllers, and remote viewing monitors. Human factors principles and experimentation have been used in the development of an advanced integrated operator control station designed for the advance servomanipulator. Key features of this next-generation design are summarized in this presentation. 7 references, 4 figures
Elements of an advanced integrated operator control station
One of the critical determinants of performance for any remotely operated maintenance system is the compatibility achieved between elements of the man/machine interface (e.g., master manipulator controller, controls, displays) and the human operator. In the remote control engineering task of the Consolidated Fuel Reprocessing Program, considerable attention has been devoted to optimizing the man/machine interface of the operator control station. This system must be considered an integral element of the overall maintenance work system which includes transporters, manipulators, remote viewing, and other parts. The control station must reflect the integration of the operator team, control/display panels, manipulator master controllers, and remote viewing monitors. Human factors principles and experimentation have been used in the development of an advanced integrated operator control station designed for the advance servomanipulator. Key features of this next-generation design are summarized in this presentation. 7 references, 4 figures
Neural Network Predictive Control Based Power System Stabilizer
Ali Mohamed Yousef
2012-04-01
Full Text Available The present study investigates the power system stabilizer based on neural predictive control for improving power system dynamic performance over a wide range of operating conditions. In this study a design and application of the Neural Network Model Predictive Controller (NN-MPC on a simple power system composed of a synchronous generator connected to an infinite bus through a transmission line is proposed. The synchronous machine is represented in detail, taking into account the effect of the machine saliency and the damper winding. Neural network model predictive control combines reliable prediction of neural network model with excellent performance of model predictive control using nonlinear Levenberg-Marquardt optimization. This control system is used the rotor speed deviation as a feedback signal. Furthermore, the using performance system of the proposed controller is compared with the system performance using conventional one (PID controller through simulation studies. Digital simulation has been carried out in order to validate the effectiveness proposed NN-MPC power system stabilizer for achieving excellent performance. The results demonstrate that the effectiveness and superiority of the proposed controller in terms of fast response and small settling time.
Design of Robust Power System Stabilizer Considering Less Control Energy
Cuk Supriyadi Ali Nandar
2012-01-01
Full Text Available This paper proposes design a robust power system stabilizer (PSS considering less control energy using a genetic algorithm (GA. The structure of proposed PSS is a 1st-order lead-lag compensator, it is easy to implement in power system utility. In the design, system uncertainties are modeled by an inverse additive uncertainty. The performance, robust stability condition, and less control energy of the designed system are formulated as the objective function in the optimization problem. The GA is applied to solve an optimization problem and to achieve control parameters of proposed PSS. The performance and robustness against system uncertainties of the proposed PSS are investigated in the single-machine infinite bus system in comparison with a conventional PSS and a PSS designed by fixed-structure H∞ loop shaping. Simulation results show that with less control energy, the robustness and damping effect of the proposed PSS can be guaranteed against various operating conditions.Keywords: Control system design, operation and control of power systems, robust control application, less control energy
Stabilization of rotational motion with application to spacecraft attitude control
Wisniewski, Rafal
2000-01-01
force. It is shown that this control law makes the system uniformly asymptotically stable to the desired reference point. The concepet is very straightforward in the Euclidean space however a global rotation control cannot be tackled.An additional modification is made to address a system which flow lies...... for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation...
Stabilization of rotational motion with application to spacecraft attitude control
Wisniewski, Rafal
2001-01-01
force. It is shown that this control law makes the system uniformly asymptotically stable to the desired reference point. The concepet is very straightforward in the Euclidean space however a global rotation control cannot be tackled.An additional modification is made to address a system which flow lies...... for global stabilization of a rotary motion. Along with a model of the system formulated in the Hamilton's canonical from the algorithm uses information about a required potential energy and a dissipation term. The control action is the sum of the gradient of the potential energy and the dissipation...
Symbolic models for nonlinear control systems without stability assumptions
Zamani, Majid; Mazo, Manuel; Tabuada, Paulo
2010-01-01
Finite-state models of control systems were proposed by several researchers as a convenient mechanism to synthesize controllers enforcing complex specifications. Existing techniques for the construction of such symbolic models have so far relied on certain stability or stabilizability assumptions. In this paper, we show that these assumptions can be relaxed and prove that large classes of unstable systems admit symbolic models. The effectiveness of the proposed results is illustrated by synthesizing a controller for an inverted pendulum subject to a schedulability constraint.
Stability and synchronization control of stochastic neural networks
Zhou, Wuneng; Zhou, Liuwei; Tong, Dongbing
2016-01-01
This book reports on the latest findings in the study of Stochastic Neural Networks (SNN). The book collects the novel model of the disturbance driven by Levy process, the research method of M-matrix, and the adaptive control method of the SNN in the context of stability and synchronization control. The book will be of interest to university researchers, graduate students in control science and engineering and neural networks who wish to learn the core principles, methods, algorithms and applications of SNN.
Advanced Discrete-Time Control Methods for Industrial Applications
Khatamianfar, Arash
2015-01-01
This thesis focuses on developing advanced control methods for two industrial systems in discrete-time aiming to enhance their performance in delivering the control objectives as well as considering the practical aspects. The first part addresses wind power dispatch into the electricity network using a battery energy storage system (BESS). To manage the amount of energy sold to the electricity market, a novel control scheme is developed based on discrete-time model predictive control (MPC) to...
Advances in Future Computer and Control Systems v.2
Lin, Sally; 2012 International Conference on Future Computer and Control Systems(FCCS2012)
2012-01-01
FCCS2012 is an integrated conference concentrating its focus on Future Computer and Control Systems. “Advances in Future Computer and Control Systems” presents the proceedings of the 2012 International Conference on Future Computer and Control Systems(FCCS2012) held April 21-22,2012, in Changsha, China including recent research results on Future Computer and Control Systems of researchers from all around the world.
Advances in Future Computer and Control Systems v.1
Lin, Sally; 2012 International Conference on Future Computer and Control Systems(FCCS2012)
2012-01-01
FCCS2012 is an integrated conference concentrating its focus on Future Computer and Control Systems. “Advances in Future Computer and Control Systems” presents the proceedings of the 2012 International Conference on Future Computer and Control Systems(FCCS2012) held April 21-22,2012, in Changsha, China including recent research results on Future Computer and Control Systems of researchers from all around the world.
Development of an advanced pitch active control system for a wide body jet aircraft
Guinn, Wiley A.; Rising, Jerry J.; Davis, Walt J.
1984-01-01
An advanced PACS control law was developed for a commercial wide-body transport (Lockheed L-1011) by using modern control theory. Validity of the control law was demonstrated by piloted flight simulation tests on the NASA Langley visual motion simulator. The PACS design objective was to develop a PACS that would provide good flying qualities to negative 10 percent static stability margins that were equivalent to those of the baseline aircraft at a 15 percent static stability margin which is normal for the L-1011. Also, the PACS was to compensate for high-Mach/high-g instabilities that degrade flying qualities during upset recoveries and maneuvers. The piloted flight simulation tests showed that the PACS met the design objectives. The simulation demonstrated good flying qualities to negative 20 percent static stability margins for hold, cruise and high-speed flight conditions. Analysis and wind tunnel tests performed on other Lockheed programs indicate that the PACS could be used on an advanced transport configuration to provide a 4 percent fuel savings which results from reduced trim drag by flying at negative static stability margins.
Optimal control of spin-stabilized spacecraft with telescoping appendages
Bainum, P. M.; Sellappan, R.
1976-01-01
The control of a spin-stabilized spacecraft consisting of a rigid central hub and one or two movable offset telescoping booms (with end masses) is considered. The equations of rotational motion are linearized about either of two desired final states. A control law for the boom end mass position is sought such that a quadratic cost functional involving the weighted components of angular velocity plus the control is minimized when the final time is unspecified and involves the solution of the matrix Riccati algebraic equation. For three axis control more than one offset boom (orthogonal to each other) is required. For two-axis control with a single boom offset from a symmetrical hub, an analytic solution is obtained; when this system is used for nutation decay the time constant is one order of magnitude smaller than previously achieved using nonoptimal control logic. For the general case results are obtained numerically.
Multivariable nonlinear control of STATCOM for synchronous generator stabilization
Sahoo, N.C. [Multimedia Univ., Melaka (Malaysia). Faculty of Engineering and Technology; Panigrahi, B.K.; Panda, G. [Multimedia Univ., Selangor (Malaysia); Dash, P.K. [National Inst. of Technology, Rourkela (India)
2004-01-01
A static synchronous compensator (STATCOM) is a typical flexible ac transmission system device playing a vital role as a stability aid for small and large transient disturbances in an interconnected power system. This article deals with design and evaluation of a feedback linearizing nonlinear controller for STATCOM installed in a single-machine infinite-bus power system. In addition to the coordinated control of ac and dc bus voltages, the proposed controller also provides good damping to the electromechanical oscillation of the synchronous generator under transient disturbances. The efficiency of the control strategy is evaluated by computer simulation studies. The comparative study of these results with the conventional cascade control structure establishes the elegance of the proposed control scheme. (author)
Advances in Computer, Communication, Control and Automation
011 International Conference on Computer, Communication, Control and Automation
2012-01-01
The volume includes a set of selected papers extended and revised from the 2011 International Conference on Computer, Communication, Control and Automation (3CA 2011). 2011 International Conference on Computer, Communication, Control and Automation (3CA 2011) has been held in Zhuhai, China, November 19-20, 2011. This volume topics covered include signal and Image processing, speech and audio Processing, video processing and analysis, artificial intelligence, computing and intelligent systems, machine learning, sensor and neural networks, knowledge discovery and data mining, fuzzy mathematics and Applications, knowledge-based systems, hybrid systems modeling and design, risk analysis and management, system modeling and simulation. We hope that researchers, graduate students and other interested readers benefit scientifically from the proceedings and also find it stimulating in the process.
Integrated controls/structures study of advanced space systems
Greene, C. S.; Cunningham, T. B.
1982-01-01
A cost tradeoff is postulated for a stiff structure utilizing minimal controls (and control expense) to point and stabilize the vehicle. Extra costs for a stiff structure are caused by weight, packaging size, etc. Likewise, a more flexible vehicle should result in reduced structural costs but increased costs associated with additional control hardware and data processing required for vibration control of the structure. This tradeoff occurs as the ratio of the control bandwidth required for the mission to the lowest (significant) bending mode of the vehicle. The cost of controlling a spacecraft for a specific mission and the same basic configuration but varying the flexibility is established.