Search results for "Linear system"

showing 10 items of 1558 documents

Robust output feedback ℌ<inf>∞</inf> control synthesis with pole placement for offshore wind turbine system: An LMI…

2012

This paper deals with output ℌ ∞ control synthesis for a linear parameter-varying model of a floating wind turbine. A nonlinear model is introduced and linearized to obtain a linear model for each desired azimuth angle using the wind turbine software FAST. The main contributions of this paper are threefold. Firstly, the family of linear models are represented based on an affine parameter-varying model structure. Secondly, the bounded parameter-varying parameters are removed using upper bounded inequalities in the control design process. Thirdly, the control problem is formulated in terms of linear matrix inequalities (LMIs). The simulation results show a comparison between a controller desi…

EngineeringOffshore wind powerMathematical optimizationbusiness.industryControl theoryLinear systemFull state feedbackLinear modelFloating wind turbineRobust controlbusinessTurbine2012 IEEE International Conference on Control Applications
researchProduct

Linear vs. non-linear classification of winners, drawers and losers at FIFA World Cup 2014

2017

Purpose: Tactical analyses to distinguish between football teams that were more or less successful have been conducted up to now only by means of linear methods (like discriminant analysis). Concer...

EngineeringOperations researchbusiness.industry030209 endocrinology & metabolismPhysical Therapy Sports Therapy and Rehabilitation030229 sport sciencesFootballLinear discriminant analysisMachine learningcomputer.software_genreLinear methods03 medical and health sciencesNonlinear system0302 clinical medicineTourism Leisure and Hospitality ManagementNotational analysisOrthopedics and Sports MedicineArtificial intelligencebusinesscomputerScience and Medicine in Football
researchProduct

Incremental dynamic based fragility assessment of reinforced concrete structures: Stationary vs. non-stationary artificial ground motions

2017

Abstract Artificial and natural records are commonly employed by researches and practitioners to perform refined seismic assessments of structures. The techniques for the generation of artificial records and their effectiveness in producing signals which are significantly representative of real earthquakes are still debated as well as results of the consequent seismic assessment to expect from their application. The paper presents an in-depth comparative study highlighting the effect of employing different typologies of artificial ground motion records on seismic assessment results, especially addressing seismic fragility curves. Three sets of 50 stationary, nonstationary evenly modulated a…

EngineeringPeak ground accelerationIncremental dynamic analysi0211 other engineering and technologiesSoil Science020101 civil engineering02 engineering and technologyIncremental dynamic analysisSpectral accelerationIncremental Dynamic Analysis0201 civil engineeringFragilitySeismic assessmentReinforced concrete structuresNonlinear dynamic analysiNon-stationary random processeNonlinear dynamic analysisCivil and Structural EngineeringReinforced concrete structureFragility curves021110 strategic defence & security studiesbusiness.industryArtificial accelerogramsNon-stationary random processesStructural engineeringArtificial accelerograms; Fragility curves; Incremental dynamic analysis; Non-stationary random processes; Nonlinear dynamic analysis; Reinforced concrete structures; Civil and Structural Engineering; Geotechnical Engineering and Engineering Geology; Soil ScienceGeotechnical Engineering and Engineering GeologyReinforced concreteArtificial accelerograms Non-stationary random processes Nonlinear dynamic analysis Incremental dynamic analysis Fragility curves Reinforced concrete structuresNonlinear systemTime historyArtificial accelerogramFragility curvebusiness
researchProduct

Monte Carlo simulation for the response analysis of long-span suspended cables under wind loads

2004

This paper presents a time-domain approach for analyzing nonlinear random vibrations of long-span suspended cables under transversal wind. A consistent continuous model of the cable, fully accounting for geometrical nonlinearities inherent in cable behavior, is adopted. The effects of spatial correlation are properly included by modeling wind velocity fluctuation as a random function of time and of a single spatial variable ranging over cable span, namely as a one-variate bi-dimensional (1V-2D) random field. Within the context of a Galerkin`s discretization of the equations governing cable motion, a very efficient Monte Carlo-based technique for second-order analysis of the response is prop…

EngineeringRandom fieldDiscretizationSuspended cablebusiness.industrysuspended cable; wind velocity random field; Proper Orthogonal DecompositionMonte Carlo methodRandom functionBuilding and ConstructionMechanicsStructural engineeringAerodynamicsProper orthogonal decompositionWind speedVibrationNonlinear systemModeling and SimulationWind velocityRandom fieldNonlinear vibrationDigital simulationbusinessCivil and Structural EngineeringWind and Structures
researchProduct

Hidden oscillations in aircraft flight control system with input saturation

2013

Abstract The presence of actuator saturation can dramatically degrade the system performance. Since the feedback loop is broken when the actuator saturates the unstable modes of the regulator may then drift to undesirable values. The consequences are that undesired nonlinear oscillations appear and that the settling time may unacceptably increase. Rigorous analysis of nonlinear aircraft models is a very difficult task, that is why a numerical simulation is often used as an analysis and design tool. In this paper difficulties of numerical analysis related to the existence of hidden oscillations in the aircraft control system are demonstrated.

EngineeringSettling timebusiness.industryDescribing functionControl engineeringGeneral MedicineFeedback loopAircraft flight control systemNonlinear systemControl theoryControl systemNonlinear OscillationsbusinessActuatorIFAC Proceedings Volumes
researchProduct

Type-2 fuzzy control of a fed-batch fermentation reactor

2010

Abstract The aim of the paper is to present the application of type-2 fuzzy logic controllers (T2FLCs) to the control of a fed-batch fermentation reactor in which the penicillin production is carried out. The performance of the control system using T2FLCs is compared by simulation with that of a control system using type-1 fuzzy logic controllers (T1FLCs). The non linear model used for the simulation study is an unstructured model characterized by the presence of non linearities, parameter uncertainty and measurement noise. Simulation results confirm the robustness of the T2FLC which shows a better performance than its type-1 counterpart particularly when uncertainties are present in the co…

EngineeringSettore ING-IND/26 - Teoria Dello Sviluppo Dei Processi ChimiciBatch fermentationbusiness.industryNon linear modelControl engineeringFuzzy control systemType (model theory)Fuzzy logicNoiseControl theoryRobustness (computer science)Control systemtype-2 fuzzy logic controller uncertainties non linear system fed batch fermentation reactorbusiness
researchProduct

Control of the Biodegradation of Mixed Wastes in a Continuous Bioreactor by a Type-2 Fuzzy Logic Controller

2009

Abstract Type-2 fuzzy logic control is proposed for nonlinear processes characterized by bifurcations. A control simulation study was conducted for a bioreactor with cell recycle containing phenol and glucose as carbon and energy sources in which a pure culture of Pseudomonas putida is carried out. The model developed by Ajbar [Ajbar, A. (2001). Stability analysis of the biodegradation of mixed wastes in a continuous bioreactor with cell recycle. Water Research, 35 (5), 1201–1208] was used for the simulations. The particular dynamics of the bioreactor, characterized by two saddle-node bifurcations, makes its control difficult, since it may become unstable also for small variations of some p…

EngineeringSettore ING-IND/26 - Teoria Dello Sviluppo Dei Processi Chimicibusiness.industryGeneral Chemical EngineeringOpen-loop controllerPID controllerControl engineeringFuzzy control systemFuzzy logicComputer Science ApplicationsNonlinear systemBifurcation Bioreactor control Stability Type-2 fuzzy logic controllerControl theoryRobustness (computer science)Energy sourcebusiness
researchProduct

Nonlinear control of an activated sludge aeration process: use of fuzzy techniques for tuning PID controllers

1999

In this paper, several tuning algorithms, specifically ITAE, IMC and Cohen and Coon, were applied in order to tune an activated sludge aeration PID controller. Performance results of these controllers were compared by simulation with those obtained by using a nonlinear fuzzy PID controller. In order to design this controller, a trial and error procedure was used to determine, as a function of error at current time and at a previous time, sets of parameters (including controller gain, integral time and derivative time) which achieve satisfactory response of a PID controller actuating over the aeration process. Once these sets of data were obtained, neural networks were used to obtain fuzzy m…

EngineeringSewageArtificial neural networkbusiness.industryApplied MathematicsOpen-loop controllerPID controllerControl engineeringNonlinear controlFuzzy logicComputer Science ApplicationsKineticsNonlinear systemOxygen ConsumptionFuzzy LogicNonlinear DynamicsControl and Systems EngineeringControl theoryProcess controlComputer SimulationBiomassElectrical and Electronic EngineeringbusinessInstrumentationAlgorithmsISA Transactions
researchProduct

Modeling the Sequential Switching Shunt Series Regulator

2005

This letter characterizes, in terms of the bandwidth and limit cycle frequency of its constituent subsystems, the sequential switching shunt series regulator -S/sup 4/R, a high-efficiency, low-mass and volume power cell devised to power the next generation of regulated power buses in telecommunication spacecrafts. Transconductance power source modeling is used to obtain linear and nonlinear models. These are used to establish a design control strategy which involves the dynamic response in large load requirements or at the end of the satellite life. Simulations and experimental results are also given to demonstrate the validity of the model.

EngineeringSpacecraftbusiness.industryTransconductanceBandwidth (signal processing)RegulatorEnergy Engineering and Power TechnologyNonlinear systemPower system simulationControl theoryLimit cycleElectrical and Electronic EngineeringbusinessShunt (electrical)IEEE Power Electronics Letters
researchProduct

Data-driven design of robust fault detection system for wind turbines

2014

Abstract In this paper, a robust data-driven fault detection approach is proposed with application to a wind turbine benchmark. The main challenges of the wind turbine fault detection lie in its nonlinearity, unknown disturbances as well as significant measurement noise. To overcome these difficulties, a data-driven fault detection scheme is proposed with robust residual generators directly constructed from available process data. A performance index and an optimization criterion are proposed to achieve the robustness of the residual signals related to the disturbances. For the residual evaluation, a proper evaluation approach as well as a suitable decision logic is given to make a correct …

EngineeringWind powerbusiness.industryMechanical EngineeringControl engineeringComputer Science Applications1707 Computer Vision and Pattern RecognitionResidualData-drivenTurbineFault detection and isolationComputer Science ApplicationsData-drivenNonlinear systemOptimization criterionPerformance indexControl and Systems EngineeringRobustness (computer science)Control theoryElectrical and Electronic EngineeringbusinessDecision tableRobustnessFault detectionWind turbineData-driven; Fault detection; Optimization criterion; Performance index; Robustness; Wind turbine; Mechanical Engineering; Computer Science Applications1707 Computer Vision and Pattern Recognition; Electrical and Electronic Engineering
researchProduct