Dissertations / Theses on the topic 'Nonlinear dynamic system modeling and control'
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Kaisare, Niket S. "Modeling, Analysis and Control of Nonlinear Switching Systems." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/6976.
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The first part of this two-part thesis examines the reverse-flow operation of auto-thermal methane reforming in a microreactor. A theoretical study is undertaken to explain the physical origins of the experimentally observed improvements in the performance of the reverse-flow operation compared to the unidirectional operation. First, a scaling analysis is presented to understand the effect of various time scales existing within the microreactor, and to obtain guidelines for the optimal reverse-flow operation. Then, the effect of kinetic parameters, transport properties, reactor design and operating conditions on the reactor operation is parametrically studied through numerical simulations. The reverse-flow operation is shown to be more robust than the unidirectional operation with respect to both optimal operating conditions as well as variations in hydrogen throughput requirements. A rational scheme for improved catalyst placement in the microreactor, which exploits the spatial temperature profiles in the reactor, is also presented. Finally, a design modification of the microreactor called "opposed-flow" reactor, which retains the performance benefits of the reverse-flow operation without requiring the input / output port switching, is suggested.
In the second part of this thesis, a novel simulation-based Approximate Dynamic Programming (ADP) framework is presented for optimal control of switching between multiple metabolic states in a microbial bioreactor. The cybernetic modeling framework is used to capture these cellular metabolic switches. Model Predictive Control, one of the most popular advanced control methods, is able to drive the reactor to the desired steady state. However, the nonlinearity and switching nature of the system cause computational and performance problems with MPC. The proposed ADP has an advantage over MPC, as the closed-loop optimal policy is computed offline in the form of so-called value or cost-to-go function. Through the use of an approximation of the value function, the infinite horizon problem is converted into an equivalent single-stage problem, which can be solved online. Various issues in implementation of ADP are also addressed.
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Moret, Eric N. "Dynamic Modeling and Control of a Car-Like Robot." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31535.
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The Flexible Low-cost Automated Scaled Highway (FLASH) laboratory at the Virginia Tech Transportation Institute (VTTI) is one of many facilities dedicated to the field of Intelligent Transportation Systems (ITS). The goal of the FLASH lab is to provide small-scale development and implementation of autonomous control strategies for today's vehicles.
The current controller used on the scale vehicles is based solely on the kinematics of the system. This body of work was aimed to develop a dynamic control law to enhance the performance of the existing kinematic controller. This control system is intended to automatically maintain the vehicle's alignment on the road as well as keep the speed of the vehicle constant. Implementation of such systems could conceivably reduce driver fatigue by removing nearly all the burden of the driving process from the driver while on the highway.
System dynamics of car-like robots with nonholonomic constraints were employed in this research to create a controller for an autonomous path following vehicle. The application of working kinematic and dynamic models describing car-like robotic systems allowed the development of a nonlinear controller.
Simulations of the vehicle and controller were done using MATLAB. Comparisons of the kinematic controller and the dynamic controller presented here were also done. In order to make the simulations model the actual system more closely, measures were taken to approximate actual sensor readings.
Master of Science
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Karakas, Deniz. "Nonlinear Modeling And Flight Control System Design Of An Unmanned Aerial Vehicle." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/3/12608926/index.pdf.
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The nonlinear simulation model of an unmanned aerial vehicle (UAV) in MATLAB®/Simulink®
environment is developed by taking into consideration all the possible major system components such as actuators, gravity, engine, atmosphere, wind-turbulence models, as well as the aerodynamics components in the 6 DOF equations of motion. Trim and linearization of the developed nonlinear model are accomplished and various related analyses are carried out. The model is validated by comparing with a similar UAV data in terms of open loop dynamic stability characteristics. Using two main approaches
namely, classical and optimal, linear controllers are designed. For the classical approach, Simulink Response Optimization (SRO) tool of MATLAB®
/Simulink®
is utilized, whereas for the optimal controller approach, linear quadratic (LQ) controller design method is implemented, again by the help of the tools put forth by MATLAB®
. The controllers are designed for control of roll, heading, coordinated turn, flight path, pitch, altitude, and airspeed, i.e., for the achievement of all low-level control functions. These linear controllers are integrated into the nonlinear model, by carrying out gain scheduling with respect to airspeed and altitude, controller input linearization regarding the perturbed states and control inputs, and anti integral wind-up scheme regarding the possible wind-up of the integrators in the controller structures. The responses of the nonlinear model controlled with the two controllers are compared based on the military flight control requirements. The advantages and disadvantages of these two frequently used controllers in industry are investigated and discussed. These results are to be evaluated by the designers themselves based on the design criteria of a project that is worked on.
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Layshot, Nicholas Joseph. "MODELING OF A GYRO-STABILIZED HELICOPTER CAMERA SYSTEM USING NEURAL NETWORKS." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/421.
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On-board gimbal systems for camera stabilization in helicopters are typically based on linear models. Such models, however, are inaccurate due to system nonlinearities and complexities. As an alternative approach, artificial neural networks can provide a more accurate model of the gimbal system based on their non-linear mapping and generalization capabilities.
This thesis investigates the applications of artificial neural networks to model the inertial characteristics (on the azimuth axis) of the inner gimbal in a gyro-stabilized multi-gimbal system. The neural network is trained with time-domain data obtained from gyro rate sensors of an actual camera system. The network performance is evaluated and compared with measured data and a traditional linear model. Computer simulation results show the neural network model fits well with the measured data and significantly outperforms a traditional model.
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Noxon, Nikola John Linn. "A MODEL PREDICTIVE CONTROL APPROACH TO ROLL STABILITY OF A SCALED CRASH AVOIDANCE VEHICLE." DigitalCommons@CalPoly, 2012. https://digitalcommons.calpoly.edu/theses/783.
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In this paper, a roll stability controller (RSC) is presented based on an eight degree of freedom dynamic vehicle model. The controller is designed for and tested on a scaled vehicle performing obstacle avoidance maneuvers on a populated test track. A rapidly-exploring random tree (RRT) algorithm is used for the vehicle to execute a trajectory around an obstacle, and examines the geographic, non-homonymic, and dynamic constraints to maneuver around the obstacle. A model predictive controller (MPC) uses information about the vehicle state and, based on a weighted performance measure, generates an optimal trajectory around the obstacle. The RSC uses the standard vehicle state sensors: four wheel mounted encoders, a steering angle sensor, and a six degree of freedom inertial measurement unit (IMU). An emphasis is placed on the mitigation of rollover and spin-out, however if a safe maneuver is not found and a collision is inevitable, the program will run a brake command to reduce the vehicle speed before impact. The trajectory is updated at a rate of 20 Hz, providing improved stability and maneuverability for speeds up to 10 ft/s and turn angles of up to 20°.
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Farid, Farshad. "On-line modeling and inverse optimal control of a class of unknown nonlinear systems using dynamic neural networks /." Available to subscribers only, 2006. http://proquest.umi.com/pqdweb?did=1240704141&sid=4&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Boberg, Frida. "Simulation of dynamic and static behavior of an electrically powered lift gate." Thesis, Linköping University, Department of Electrical Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11627.
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Continental Automotive Systems is a German company that develops control systems for different applications in cars. A control system for electrically powered lift gates that are opened or closed on the driver’s command is one of the products developed. The drive system itself is composed of a spindle that is driven by a DC-motor over a gear and a spring. When developing the control system it is convenient to use a simulation model instead of having to implement it on the system every time. The simulation analytically describes how the system is behaving.
In this thesis a simulation model of a drive system and a lift gate is developed and evaluated. The model parameters are estimated using System Identification Toolbox in Matlab.
Continental Automotive Systems är ett tyskt företag som utvecklar styrsystem för olika tillämpningar i bilar. Bland annat utvecklas ett styrsystem till eldrivna bakluckor som öppnas och stängs av föraren per knapptryck. Själva drivanordningen består av en skruv som drivs av en likströmsmotor över en utväxling och en fjäder. Då man vill utveckla styrsystemet utan att behöva implementera det på systemet varje gång är en simuleringsmodell av drivanordningen och luckan ett bra hjälpmedel. Denna simuleringsmodell kan då analytiskt beräkna hur systemet uppför sig.
I detta examensarbete har en simuleringsmodell av en drivanordning med tillhörande lucka utvecklats och utvärderats. Modellparametrarna estimerades med hjälp av System Identification Toolbox i Matlab.
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Singla, Puneet. "Multi-resolution methods for high fidelity modeling and control allocation in large-scale dynamical systems." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3785.
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This dissertation introduces novel methods for solving highly challenging model-
ing and control problems, motivated by advanced aerospace systems. Adaptable, ro-
bust and computationally effcient, multi-resolution approximation algorithms based
on Radial Basis Function Network and Global-Local Orthogonal Mapping approaches
are developed to address various problems associated with the design of large scale
dynamical systems. The main feature of the Radial Basis Function Network approach
is the unique direction dependent scaling and rotation of the radial basis function via
a novel Directed Connectivity Graph approach. The learning of shaping and rota-
tion parameters for the Radial Basis Functions led to a broadly useful approximation
approach that leads to global approximations capable of good local approximation
for many moderate dimensioned applications. However, even with these refinements,
many applications with many high frequency local input/output variations and a
high dimensional input space remain a challenge and motivate us to investigate an
entirely new approach. The Global-Local Orthogonal Mapping method is based upon
a novel averaging process that allows construction of a piecewise continuous global
family of local least-squares approximations, while retaining the freedom to vary in
a general way the resolution (e.g., degrees of freedom) of the local approximations.
These approximation methodologies are compatible with a wide variety of disciplines
such as continuous function approximation, dynamic system modeling, nonlinear sig-nal processing and time series prediction. Further, related methods are developed
for the modeling of dynamical systems nominally described by nonlinear differential
equations and to solve for static and dynamic response of Distributed Parameter Sys-
tems in an effcient manner. Finally, a hierarchical control allocation algorithm is
presented to solve the control allocation problem for highly over-actuated systems
that might arise with the development of embedded systems. The control allocation
algorithm makes use of the concept of distribution functions to keep in check the
"curse of dimensionality". The studies in the dissertation focus on demonstrating,
through analysis, simulation, and design, the applicability and feasibility of these ap-
proximation algorithms to a variety of examples. The results from these studies are
of direct utility in addressing the "curse of dimensionality" and frequent redundancy
of neural network approximation.
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Wiese, Johannes Jacobus. "System identification and model-based control of a filter cake drying process." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6654.
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Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: A mineral concentrate drying process consisting of a hot gas generator, a flash dryer and a feeding section is found to be the bottleneck in the platinum concentrate smelting process. This operation is used as a case study for system identification and model-based control of dryers. Based on the availability of a month's worth of dryer data obtained from a historian, a third party modelling and control software vendor is interested in the use of this data for data driven model construction and options for dryer control. The aimed contribution of this research is to use only data driven techniques and attempt an SID experiment and use of this model in a controller found in literature to be applicable to the dryer process. No first principle model was available for simulation or interpretation of results. Data were obtained for the operation from the plant historian, reduced, cleaned and investigated for deterministic information through surrogate data comparison – resulting in usable timeseries from the plant data. The best datasets were used for modelling of the flash dryer and hot gas generator operations individually, with the hot gas generator providing usable results. The dynamic, nonlinear autoregressive models with exogenous inputs were identified by means of a genetic programming with orthogonal least squares toolbox. The timeseries were reconstructed as a latent variable set, or “pseudo-embedding”, using the delay parameters as identified by average mutual information, autocorrelation and false nearest neighbours. The latent variable reconstruction resulted in a large solution space, which need to be investigated for an unknown model structure. Genetic Programming is capable of identifying unknown structures. Freerun prediction stability and sensitivity analysis were used to assess the identified best models for use in model based control. The best two models for the hot gas generator were used in a basic model predictive controller in an attempt to only track set point changes. One step ahead modelling of the flash dryer outlet air temperature was unsuccessful with the best model obtaining a validation R2 = 43%. The lack of process information contained in the available process variables are to blame for the poor model identification. One-step ahead prediction of the hot gas generator resulted in a top model with validation R2 = 77.1%. The best two hot gas generator models were implemented in a model predictive controller constructed in a real time plant data flow simulation. This controller's performance was measured against set point tracking ability. The MPC implementation was unsuccessful due to the poor freerun prediction ability of the models. The controller was found to be unable to optimise the control moves using the model. This is assigned to poor model freerun prediction ability in one of the models and a too complex freerun model structure required. It is expected that the number of degrees of freedom in the freerun model is too much for the optimiser to handle. A successful real time simulation architecture for the plant dataflow could however be constructed in the supplied software. It is recommended that further process measurements, specifically feed moisture content, feed temperature and air humidity, be included for the flash dryer; closed loop system identification be investigated for the hot gas generator; and a simpler model structure with smaller reconstructed latent variable regressor set be used for the model predictive controller.
AFRIKAANSE OPSOMMING: 'n Drogings proses vir mineraal konsentraat bestaan uit drie eenhede: 'n lug verwarmer-, 'n blitsdroeër- en konsentraat toevoer eenheid. Hierdie droeër is geïdentifiseer as die bottelnek in die platinum konsentraat smeltingsproses. Die droeër word gebruik as 'n gevallestudie vir sisteem identifikasie asook model-gebasseerder beheer van droeërs. 'n Maand se data verkry vanaf die proses databasis, het gelei tot 'n derde party industriële sagteware en beheerstelsel maatskappy se belangstelling in data gedrewe modelering en beheer opsies vir die drogings proses. Die doelwit van hierdie studie is om data gedrewe modeleringstegnieke te gebruik en die model in 'n droeër-literatuur relevante beheerder te gebruik. Geen eerste beginsel model is beskikbaar vir simulasie of interpretasie van resultate nie. Die verkrygde data is gereduseer, skoon gemaak en bestudeer om te identifiseer of die tydreeks deterministiese inligting bevat. Dit is gedoen deur die tydreeks met stochastiese surrogaat data te vergelyk. Die mees gepaste datastelle is gebruik vir modellering van die blitsdroeër en lugverwarmer afsonderlik. Die nie-liniêre, dinamiese nie-linieêre outeregressie modelle met eksogene insette was deur 'n genetiese programmering algoritme, met ortogonale minimum kwadrate, identifiseer. Die betrokke tydreeks is omskep in 'n hulp-veranderlike stel deur gebruik te maak van vertragings-parameters wat deur gemiddelde gemeenskaplike inligting, outokorrelasie en vals naaste buurman metodes verkry is. Die GP algoritme is daartoe in staat om the groot oplossings ruimte wat deur hierdie hulp-veranderlike rekonstruksie geskep word, te bestudeer vir 'n onbekende model struktuur. Die vrye vooruitskattings vermoë, asook die model sensitiwiteit is inag geneem tydens die analiese van die resultate. Die beste modelle se gepastheid tot model voorspellende beheer is gemeet deur die uitkomste van 'n sensitiwiteits analise, asook 'n vrylopende voorspelling, in oënskou te neem. Die een-stap vooruit voorspellende model van die droeër was onsusksesvol met die beste model wat slegs 'n validasie R2 = 43% kon behaal. Die gebrekkige meet instrumente in die droeër is te blameer vir die swak resultate. Die een-stap vooruit voorspellende model van die lug verwarmer wat die beste gevaar het, het 'n validasie R2 = 77.1% gehad. 'n Basiese model voorspellende beheerder is gebou deur die 2 beste modelle van slegs die lugverwarmer te gebruik in 'n intydse simulasie van die raffinadery data vloei struktuur. Hierdie beheerder se vermoë om toepaslike beheer uit te oefen, is gemeet deur die slegs die stelpunt te verander. Die beheerder was egter nie daartoe in staat om die insette te optimeer, en so die stelpunt te volg nie. Hierdie onvermoë is as gevolg van die kompleks vrylopende model struktuur wat oor die voorspellingsvenster optimeer moet word, asook die onstabiele vryvooruitspellings vermoë van die modelle. Die vermoede is dat die loslopende voorspelling te veel vryheids grade het om die insette maklik genoeg te optimeer. Die intydse simulasie van die raffinadery se datavloei struktuur was egter suksesvol. Beter meting van noodsaaklike veranderlikes vir die droër, o.a. voginhoud van die voer, voer temperatuur, asook lug humiditeit; geslotelus sisteem identifikasie vir die lugverwarmer; asook meer eenvoudige model struktuur vir gebruik in voorspellende beheer moontlik vermag deur 'n kleiner hulp veranderlike rekonstruksie te gebruik.
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Castillo, Zamora José de Jesús. "Conception, Modélisation et Contrôle d'un Système Multi-Drones pour la Manipulation Aérienne." Electronic Thesis or Diss., université Paris-Saclay, 2021. http://www.theses.fr/2021UPASG051.
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Un sujet passionnant dans le domaine des véhicules aériens autonomes est l'interaction avec l'environnement par la manipulation en vol, y compris la récupération, le transport et le déploiement, qui dévoile un énorme potentiel vis-à-vis des applications industrielles et de service. À cet égard, cette thèse doctoral se concentre sur la conception et l'étude dynamique basé sur l'énergie d'un système aérien sans pilote à liaisons multiples capable d'effectuer des tâches de manipulation. L'étude de ce système aérien comprend le contrôle du véhicule volant à liaisons multiples par la théorie du contrôle en mode glissant, la conception de contrôleurs basés sur le principe de Lyapunov et, parallèlement, à l'application de filtres de Kalman pour l'estimation de l'état et des perturbations. La dernière partie de la thèse est consacrée à l'examen des effets des retards sur les drones. Des résultats de simulation sont fournis pour prouver l'efficacité de la proposition globale de la thèseA recent and exciting topic within the field of autonomous aerial vehicles is the interaction with the surrounding environment via in-flight manipulation, including retrieving, transport and deployment, which unveils an enormous potential vis-a-vis industrial and service applications. In this regard, the actual thesis focuses on the conception and energy-based dynamical study of a multi-link unmanned aerial system able to perform manipulation tasks. The study of the aforementioned robotic aerial system includes the control of the flying multi-link vehicle by the sliding mode control theory and the conception of Lyapunov-based controllers alongside the application of Kalman Filters for state and disturbances estimation. The last part of the thesis is devoted to the examination of time-delays effects on unmanned aerial systems. Detailed simulation results are provided to prove the effectiveness of the overall thesis proposal
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Bichiou, Youssef. "Modeling Analysis and Control of Nonlinear Aeroelastic Systems." Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/71760.
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Airplane wings, turbine blades and other structures subjected to air or water flows, can undergo motions depending on their flexibility. As such, the performance of these systems depends strongly on their geometry and material properties. Of particular importance is the contribution of different nonlinear aspects. These aspects can be of two types: aerodynamic and structural. Examples of aerodynamic aspects include but are not lomited to flow separation and wake effects. Examples of structural aspects include but not limited to large deformations (geometric nonlinearities), concentrated masses or elements (inertial nonlinearities) and freeplay. In some systems, and depending on the parameters, the nonlinearities can cause multiple solutions. Determining the effects of nonlinearities of an aeroelastic system on its response is crucial.
In this dissertation, different aeroelastic configurations where nonlinear aspects may have significant effects on their performance are considered. These configurations include: the effects of the wake on the flutter speed of a wing placed under different angles of attack, the impacts of the wing rotation as well as the aerodynamic and structural nonlinearities on the flutter speed of a rotating blade, and the effects of the recently proposed nonlinear energy sink on the flutter and ensuing limit cycle oscillations of airfoils and wings. For the modeling and analysis of these systems, we use models with different levels of fidelity as required to achieve the stated goals. We also use nonlinear dynamic analysis tools such as the normal form to determine specific effects of nonlinearities on the type of instability.Ph. D.
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Itik, Mehmet. "Nonlinear dynamical systems with applications to cancer modelling and control." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531236.
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Koulouris, Alexandros. "Multiresolution learning in nonlinear dynamic process modeling and control." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11376.
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Zhao, Xin. "Empirical dynamic modeling and nonlinear force control of friction stir welding." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Zhao_09007dcc803fbd7f.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed February 4, 2008) Includes bibliographical references.
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Han, Myung-Chul. "Robust control design for uncertain nonlinear dynamic systems." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/16850.
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Bajracharya, Quree. "Dynamic Modeling, Monitoring and Control of Energy Storage System." Thesis, Karlstads universitet, Fakulteten för teknik- och naturvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-26521.
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Today there is a great interest on the small scale renewable electricity generation due to the changing economics and the demand for highly sustainable electricity generation. However, renewable energy sources are unreliable and fluctuating which causes variation of power flow. In this situation, there can be server problems such as frequency oscillations, violation of the power line capability jeopardizing the security of the power system. Batteries can be an emerging technology which acts as the fast acting spinning reserve that can balance between the load and generation. Conversely, it very difficult to accurately predict battery performance and the total cost of the investment of storage system by integrating batteries to the renewable system as batteries in this situation have to bear a wide range of the operational conditions . Henceforth, modeling of the battery is extremely important. This master thesis gives the dynamic modeling of the batteries which can replicate the relevant behavior of the battery. The proposed methodology is the model based approach where the parameters are determined to develop a suitable model. In this thesis, the battery is modeled as an R-C circuit comprising of elements each of which represents certain battery characteristics. An appropriate model is selected based on the comparative study of the characteristics of experimental output of the battery using model identification. Parameters of the battery are computed in the MATLAB Simulink parameter estimation toolbox using least square estimation .The initial parameter values for the simulink are found with the help of the lab test. Validation results from the two experimental data shows that the model can accurately estimate the battery characteristics with an error of 0.3%.The aforementioned battery model is later used to make an appropriate charge controller. The methods used in the thesis performed quite well within the limited tests performed during the experimental works. To use the model online in the future, further investigation is recommended in order to refine the model.
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Maleki, Ehsan A. "Dynamics and control of a small-scale mobile boom crane." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37166.
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Boom cranes are one of the most dynamically complicated types of cranes because they possess rotational joints as opposed to the linear tracks of bridge and gantry cranes. In addition, if the boom crane is placed on a mobile base, additional complexity is added to the system. However, mobile boom cranes have huge potential benefits as they can be quickly transported from one location to another. Furthermore, if they utilize their mobile base during lifting operations, then they can have an extremely large workspace. All cranes share the same limiting weakness; the payload oscillates when the crane moves. A command-generation approach is taken to control the payload oscillation. Input shaping is one such command-generation technique that modifies the original reference command by convolving it with a series of impulses. The shaped command produced by the convolution can then move the crane without inducing payload oscillation. Input shaping can accommodate parameter uncertainties, nonlinearities, multiple modes of vibration, and has been shown to be compatible with human operators. This thesis focuses on three aspects of mobile boom cranes: 1) dynamic analysis, 2) input-shaping control, and 3) experimental testing. A majority of the thesis focuses on analyzing and describing the complicated dynamics of mobile boom cranes. Then, various input-shaping controllers are designed and tested, including two-mode shapers for double-pendulum dynamics. In order to experimentally verify the simulation results, a small-scale mobile boom crane has been constructed. The details of the mobile boom crane and its important features are presented and discussed. Details of the software used to control the crane are also presented. Then, several different experimental protocols are introduced and the results presented. In addition, a set of operator performance studies that analyze human operators maneuvering the mobile boom crane through an obstacle course is presented.
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Souza, Eric Conrado de. "Modelagem e controle de uma classe de sistemas multi-corpos móveis." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-04092008-163727/.
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No que segue, propõe-se uma classe de sistemas robóticos multi-corpos, cujos corpos componentes estão fisicamente acoplados através de juntas rotativas ativas. Os sistemas da classe considerada possuem mobilidade irrestrita no espaço plano uma vez que propulsores distribuídos ao longo dos corpos do sistema. A modelagem dinâmica destes sistemas é apresentada sob as abordagens Hamiltoniana e Lagrangiana da mecânica analítica. A descrição destes métodos de modelagem, assim como os modelos por eles obtidos, é realizada com ênfase na interpretação geométrica da matemática envolvida. Alguns exemplos de parametrizações do espaço de fase do sistema são discutidos e exemplos de modelagem em função destas parametrizações são obtidos. Ademais, alguns critérios de análise de controlabilidade não-linear são revisados e aplicados aos modelos do sistema com a estrutura de entradas considerada. Alguns casos de estabilização da classe de sistemas são também discutidos. Resultados de simulação de estabilização são obtidos para sistemas através de estudos de casos. Sistemas completamente controlados no espaço de estados podem ser linearizados através de uma técnica de linearização por realimentação e estabilizados com uma realimentação de estados. Para os sistemas cuja controlabilidade é deficiente, propõe-se a modificação de um método de controle de sistemas sub-atuados e uma lei de controle por realimentação é obtida pela teoria de estabilidade de Lyapunov. A classe de sistemas aqui discutida possui grande potencial de aplicação nos ambientes espacial e submarino.In the following, a class of multi-body robotic systems is proposed in which its system component bodies are physically coupled by active rotating joints. The systems belonging to the proposed class have unrestricted mobility on the plane since thrusters are distributed along the system. System dynamical modeling is obtained through the analytic mechanical Hamiltonian and Lagrangian methods. The presentation of these methods, as well as the dynamical models obtained by them, is realized with an emphasis in the geometrical interpretation of the corresponding mathematics. A few different system phase space parameterizations approaches are discussed and modeling examples are presented under these parameterizations. Additionally, some nonlinear controllability analysis criteria are reviewed and applied to system dynamical models composed by the input structure mentioned above. A few stabilization case studies for the class of systems are also discussed and simulation results are presented. Totally controlled systems in the phase space can be linearized by feedback linearization techniques and stabilized through a state feedback. For partially controllable systems a modification of a stabilization method for under-actuated systems is proposed which renders feedback control via Lypunov stability theory. The class of systems discussed has great potential for space and underwater applications.
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Qi, Chenkun. "Modeling of nonlinear distributed parameter system for industrial thermal processes /." access full-text access abstract and table of contents, 2009. http://libweb.cityu.edu.hk/cgi-bin/ezdb/thesis.pl?phd-meem-b23750911f.pdf.
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Thesis (Ph.D.)--City University of Hong Kong, 2009."Submitted to Department of Manufacturing Engineering and Engineering Management in partial fulfillment of the requirements for the degree of Doctor of Philosophy." Includes bibliographical references (leaves 167-187)
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Haipeng, Xie. "Flexible dynamic modeling and control for the remote manipulator system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq26007.pdf.
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Arcila, Ana María Molina. "High resolution Fabry-Pérot interferometer - dynamic system modeling and nanopositioning control system design." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-23122014-155735/.
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This work represents the research project to obtain the degree of Master of Sciences in Electrical Engineering, specializing in Systems Engineering, at the Escola Politécnica of the Universidade de São Paulo, in São Paulo, Brazil. The main objective of the project is to design the mirror nanopositioning controller of the state-of-the-art Fabry-Pérot interferometer to be installed in the Brazilian Tunable Filter Imager (BTFI) on the Southern Astrophysical Research (SOAR) telescope in Chile. A three-input-three-output multivariable prototype of the Fabry-Pérot system is comprised of three high-range Amplified Piezoelectric Actuators (APA) of 360 m stroke and three 400 m range capacitive measurement systems. A characterization of the instrumentation of the system, which consists of capacitive sensors and capacitance-to-voltage converters, piezoelectric actuators, power drivers of the piezoelectric actuators and data acquisition system was done as part of the identification and study of the system. With the characterization of the system, a sixth-order complete system model was built on top of a second-order piezoelectric actuator parametric model, required for the design of the controllers. Subsequently, the scientific specifications were translated to a control problem and the design of a robust controller was made following the Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR) method. Also a Proportional-Integral controller tuned using a genetic algorithm was designed to be used as benchmark. Finally the built controllers were validated in the real system. Results show that both controllers achieve the performance requirements of following reference signals and having null steady-state error. However, the robust controller is by far the best suited for the Fabry- Pérot instrument in terms of performance and stability because of its higher bandwidth and robustness to modeling errors.Este trabalho apresenta o projeto de pesquisa para obtenção do título de Mestre em Engenharia Elétrica, área de concentração de engenharia de sistemas, da Escola Politécnica da Universidade de São Paulo. O objetivo principal deste projeto foi desenvolver um controlador de nanoposicionamento para o interferômetro de Fabry-Pérot que será instalado no instrumento BTFI (Brazilian Tunable Filter Imager), no telescópio SOAR (Southern Astrophysical Research Telescope), no Chile. O interferômetro de Fabry-Pérot é um sistema multivariável de três entradas e três saídas composto por três atuadores piezoelétricos de 370 m de deslocamento, e três sistemas capacitivos de medida de distância de 400 m de faixa de medição. A caracterização da instrumentação do sistema, que consiste em sensores capacitivos, conversores de capacitância para tensão, atuadores piezoelétricos, drivers de potência para os atuadores piezoelétricos e sistemas de aquisição de dados, fez parte do estudo e da identificação do sistema. Após a caracterização da instrumentação, foi desenvolvido um modelo físico de sexta ordem para o sistema completo, partindo do modelo de segunda ordem dos atuadores piezoelétricos. Este modelo é necessário para o projeto dos controladores. Subsequentemente, as especificações científicas foram traduzidas em um problema de controle e o projeto do controlador robusto foi feito seguindo a técnica LQG/LTR (Linear Quadratic Gaussian/Loop Transfer Recovery). Um controlador Proporcional-Integral (PI) também foi desenvolvido e sintonizado usando um algoritmo genético, para funcionar como ponto de comparação. Finalmente, os controladores desenvolvidos foram validados no sistema real. Com os resultados concluiu-se que ambos controladores atingiram as especificações de desempenho no que diz respeito a seguir sinais de referência com erro nulo no estado estacionário. Pôde-se concluir ainda que o controlador robusto mostrou-se mais adaptado ao instrumento Fabry- Pérot em termos de desempenho e estabilidade, pois, comparado ao PI, é um controlador com maior largura de banda e robustez aos erros de modelamento.
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Petersson, Daniel. "A Nonlinear Optimization Approach to H2-Optimal Modeling and Control." Doctoral thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-93324.
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Mathematical models of physical systems are pervasive in engineering. These models can be used to analyze properties of the system, to simulate the system, or synthesize controllers. However, many of these models are too complex or too large for standard analysis and synthesis methods to be applicable. Hence, there is a need to reduce the complexity of models. In this thesis, techniques for reducing complexity of large linear time-invariant (lti) state-space models and linear parameter-varying (lpv) models are presented. Additionally, a method for synthesizing controllers is also presented. The methods in this thesis all revolve around a system theoretical measure called the H2-norm, and the minimization of this norm using nonlinear optimization. Since the optimization problems rapidly grow large, significant effort is spent on understanding and exploiting the inherent structures available in the problems to reduce the computational complexity when performing the optimization. The first part of the thesis addresses the classical model-reduction problem of lti state-space models. Various H2 problems are formulated and solved using the proposed structure-exploiting nonlinear optimization technique. The standard problem formulation is extended to incorporate also frequency-weighted problems and norms defined on finite frequency intervals, both for continuous and discrete-time models. Additionally, a regularization-based method to account for uncertainty in data is explored. Several examples reveal that the method is highly competitive with alternative approaches. Techniques for finding lpv models from data, and reducing the complexity of lpv models are presented. The basic ideas introduced in the first part of the thesis are extended to the lpv case, once again covering a range of different setups. lpv models are commonly used for analysis and synthesis of controllers, but the efficiency of these methods depends highly on a particular algebraic structure in the lpv models. A method to account for and derive models suitable for controller synthesis is proposed. Many of the methods are thoroughly tested on a realistic modeling problem arising in the design and flight clearance of an Airbus aircraft model. Finally, output-feedback H2 controller synthesis for lpv models is addressed by generalizing the ideas and methods used for modeling. One of the ideas here is to skip the lpv modeling phase before creating the controller, and instead synthesize the controller directly from the data, which classically would have been used to generate a model to be used in the controller synthesis problem. The method specializes to standard output-feedback H2 controller synthesis in the lti case, and favorable comparisons with alternative state-of-the-art implementations are presented.
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Silva, Margarida M. "Nonlinear Modeling and Feedback Control of Drug Delivery in Anesthesia." Doctoral thesis, Uppsala universitet, Avdelningen för systemteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233290.
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General anesthesia is a drug-induced reversible state where neuromuscular blockade (NMB), hypnosis, and analgesia (jointly denoted by depth of anesthesia - DoA) are guaranteed. This thesis concerns mathematical modeling and feedback control of the effect of the muscle relaxants atracurium and rocuronium, the hypnotic propofol, and the analgesic remifentanil. It is motivated by the need to reduce incidences of awareness and overdose-related post-operative complications that occur in standard clinical practice. A major challenge for identification in closed-loop is the poor excitation provided by the feedback signal. This applies to the case of drugs administered in closed-loop. As a result, the standard models for the effect of anesthetics appear to be over-parameterized. This deteriorates the result of system identification and prevents individualized control. In the first part of the thesis, minimally parameterized models for the single-input single-output NMB and the multiple-input single-output DoA are developed, using real data. The models have a nonlinear Wiener structure: linear time-invariant dynamics cascaded with a static nonlinearity. The proposed models are shown to improve identifiability as compared to the standard ones. The second part of the thesis presents system identification methods for Wiener systems: a batch prediction error method, and two recursive techniques, one based on the extended Kalman filter, and another based on the particle filter. Algorithms are given for both the NMB and the DoA using the minimally parameterized models. Nonlinear adaptive controllers are proposed in the third part of the thesis. Using the model parameter estimates from the extended Kalman filter, the controller performs an online inversion of the Wiener nonlinearity. A pole-placement controller or a linear quadratic Gaussian controller is used for the linearized system. Results show good reference tracking performance both in simulation and in real trials. Relating to patient safety, the existence of undesirable sustained oscillations as consequence of Andronov-Hopf bifurcations for a NMB PID-controlled system is analyzed. Essentially the same bifurcations are observed in the standard and the minimally parameterized models, confirming the ability of the latter to predict the nonlinear behavior of the closed-loop system. Methods to design oscillation-free controllers are outlined.
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Gustavsson, Andreas. "Dynamic modeling and Model Predictive Control of a vapor compression system." Thesis, Linköpings universitet, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76352.
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The focus of this thesis was on the development of a dynamic modeling capability for a vapor compression system along with the implementation of advanced multivariable control techniques on the resulting model. Individual component models for a typical vapor compression system were developed based on most recent and acknowledged publications within the field of thermodynamics. Parameter properties such as pressure, temperature, enthalpy etc. for each component were connected to detailed thermodynamic tables by algorithms programmed in MATLAB, thus creating a fully dynamic environment. The separate component models were then interconnected and an overall model for the complete system was implemented in SIMULINK. An advanced control technique known as Model Predictive Control (MPC) along with an open-source QP solver was then applied on the system. The MPC-controller requires the complete state information to be available for feedback and since this is often either very expensive (requires a great number of sensors) or at times even impossible (difficult to measure), a full-state observer was implemented. The MPC-controller was designed to keep certain system temperatures within tight bands while still being able to respond to varying cooling set-points. The control architecture was successful in achieving the control objective, i.e. it was shown to be adaptable in order to reflect changes in environmental conditions. Cooling demands were met and the temperatures were successfully kept within given boundaries.
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Cho, Jeongho. "Multiple modeling and control of nonlinear systems with self-organizing maps." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008180.
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Villella, Matthew G. "Nonlinear Modeling and Control of Automobiles with Dynamic Wheel-Road Friction and Wheel Torque Inputs." Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5198.
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This thesis presents a new nonlinear automobile dynamical model and investigates the possibility of automobile dynamic control with wheel torque utilizing this model. The model has been developed from first principles by applying classical mechanics. Inputs to the model are the four independent wheel torques, while the steer angles at each wheel are specified as independent time-varying signals. In this way, consideration of a variety of steering system architectures, including rear-wheel steer, is possible, and steering introduces time-varying structure into the vehicle model.
The frictional contact at the wheel-road interface is modeled by use of the LuGre dynamic friction model. Extensions to the existing two-dimensional LuGre friction model are derived and the steady-state of the friction model is compared to existing static friction models. Simulation results are presented to validate the model mathematics and to explore automobile behavior in a variety of scenarios.
Vehicle control with wheel torque is explored using the theory of input-output linearization for multi-input multi-output systems. System relative degree is analyzed and use of steady-state LuGre friction in a control design model is shown to give rise to relative degree singularities when no wheel slip occurs. Dynamic LuGre friction does not cause such singularities, but instead has an ill-defined nature under the same no-slip condition. A method for treating this ill-defined condition is developed, leading to the potential for the system to have relative degree.
Longitudinal velocity control and combined longitudinal and angular vehicle velocity control are demonstrated in simulation using input-output linearization, and are shown to produce improved vehicle response as compared to the open-loop behavior of the automobile. Robustness of the longitudinal velocity control to friction model parameter variation is explored and little impact to the controller's ability to track the desired trajectory is observed.
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Song, Xubin. "Design of Adaptive Vibration Control Systems with Applicaion to Magneto-Rheological Dampers." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29556.
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The design of nonlinear adaptive control systems for reducing vibration transmission in applications such as transportation systems is discussed. The systems studied include suspension systems, such as those used in vehicles, employing nonlinear magneto-rheological (MR) dampers that are controlled to provide improved vibration isolation. Magneto-rheological dampers use a novel class of smart fluid whose apparent viscosity changes as it is exposed to a magnetic field. The developed adaptive control scheme is designed to deal with the nonlinearities and uncertainties that commonly arise in most suspension applications. Some of the nonlinearities that are considered include time-varying characteristics, displacement-dependent effects, and hysterisis damping of magneto-rheological dampers. The uncertainties include mass and stiffness variations that can commonly occur in a suspension system. A number of nonlinear analytical models are developed and used in numerical simulation to evaluate the validity and effectiveness of the developed adaptive controllers. Further, the results of the numerical study are used in an experimental evaluation of the controllers on a seat suspension for heavy vehicles. The analytical and experimental evaluation both indicate the effectiveness of the proposed adaptive control technique in controlling vibration transmission in the presence of both system nonlinearities and uncertainties. The manuscript will provide a detail account of the modeling, dynamic analysis, adaptive control development, and testing that was performed throughout this study.Ph. D.
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Rajapakse, Nuraj I. "Analytical modeling, analysis and robust control of uncertain nonlinear dynamical systems by using sliding mode control (SMC) and quantitative feedback theory (QFT)." Ann Arbor, Mich. : ProQuest, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3218185.
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Thesis (Ph.D. in Mechanical Engineering)--S.M.U.Title from PDF title page (viewed July 13, 2007). Source: Dissertation Abstracts International, Volume: 67-05, Section: B, page: 2801. Adviser: Gemunu S. Happawana. Includes bibliographical references.
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Narby, Erik. "Modeling and Estimation of Dynamic Tire Properties." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6153.
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Information about dynamic tire properties has always been important for drivers of wheel driven vehicles. With the increasing amount of systems in modern vehicles designed to measure and control the behavior of the vehicle information regarding dynamic tire properties has grown even more important.
In this thesis a number of methods for modeling and estimating dynamic tire properties have been implemented and evaluated. The more general issue of estimating model parameters in linear and non-linear vehicle models is also addressed.
We conclude that the slope of the tire slip curve seems to dependent on the stiffness of the road surface and introduce the term combined stiffness. We also show that it is possible to estimate both longitudinal and lateral combined stiffness using only standard vehicle sensors.
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Gil, Iván-Dario. "Modeling, Simulation, Dynamic Optimization and Control of a Semibatch Emulsion Polymerization Process." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0036/document.
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Dans ce travail, la modélisation, la simulation, l'optimisation dynamique et la commande nonlinéaire d'un procédé industriel de polymérisation en émulsion produisant du polyacétate de vinyle (PVAc) sont étudiées. La réaction est modélisée comme un système à deux phases constitué d'une phase aqueuse et une phase particulaire. Un modèle détaillé est développé pour calculer la masse molaire moyenne en poids, la masse molaire moyenne en nombre et la dispersité. Les moments de chaînes en croissance et terminés sont utilisés pour représenter l'état du polymère et pour calculer la distribution de masse molaire (MWD). L'étude de cas correspond à un réacteur industriel fonctionnant dans une entreprise de produits chimiques à Bogotá. Un réacteur à l'échelle industrielle (11 m3 de capacité) est simulé dans lequel une réaction semi-batch de polymérisation en émulsion de l'acétate de vinyle est effectuée. Le problème d'optimisation dynamique est résolu directement en utilisant un solveur de programmation non linéaire. L'intégration des équations différentielles est faite en utilisant la méthode de Runge-Kutta. Trois problèmes d'optimisation différents sont résolus, depuis le plus simpliste (une seule variable d'optimisation : la température du réacteur) au plus complexe (trois variables d'optimisation : la température du réacteur, le débit de l'amorceur et le débit du monomère) en vue de minimiser le temps final de réaction. Une réduction de 25% du temps de traitement par batchs est réalisée par rapport aux conditions normales de fonctionnement appliquées dans l'entreprise. Les résultats montrent qu'il est possible de minimiser la durée de réaction alors que certaines qualités de polymères souhaitées (conversion, masse molaire et contenu en solides) satisfont les contraintes définies. Une technique de commande non linéaire géométrique à l'aide de la linéarisation entrée/sortie est adaptée à la régulation de la température du réacteur. Un filtre Kalman étendu (EKF) est mis en oeuvre pour estimer les états non mesurés et il est testé dans différents cas, dont une étude de robustesse où des erreurs du modèle sont introduites pour vérifier son bon fonctionnement. Après vérification des performances du régulateur, certains changements d'opération du procédé ont été proposés afin d'améliorer la productivité du procédé et la qualité du polymère. Enfin, le profil de température optimale et les politiques d'alimentation optimales de débits du monomère et de l'amorceur, obtenues dans l'étape d'optimisation dynamique, ont fourni les consignes optimales pour la commande non linéaire. Les résultats montrent que le régulateur non linéaire conçu ici convient pour suivre les trajectoires optimales de température calculées précédemmentIn this work, modeling, simulation, dynamic optimization and nonlinear control of an industrial emulsion polymerization process to produce poly-vinyl acetate (PVAc) are proposed. The reaction is modeled as a two-phase system composed of an aqueous phase and a particle phase. A detailed model is used to calculate the weight average molecular weight, the number average molecular weight and the dispersity. The moments of the growing and dead chains are used to represent the state of the polymer and to calculate the molecular weight distribution (MWD). The case study corresponds to an industrial reactor operated at a chemical company in Bogotá. An industrial scale reactor (11 m3 of capacity) is simulated where a semi-batch emulsion polymerization reaction of vinyl acetate is performed. Dynamic optimization problem is solved directly using a Nonlinear Programming solver. Integration of differential equations is made using Runge-Kutta method. Three different optimization problems are solved from the more simplistic (only one control variable: reactor temperature) to the more complex (three control variables : reactor temperature, initiator flow rate and monomer flow rate) in order to minimize the reaction time. A reduction of 25% of the batch time is achieved with respect to the normal operating conditions applied at the company. The results show that is possible to minimize the reaction time while some polymer desired qualities (conversion, molecular weight and solids content) satisfy the defined constraints. A nonlinear geometric control technique by using input/output linearization is adapted to the reactor temperature control. An extended Kalman filter (EKF) is implemented to estimate unmeasured states and it is tested in different cases including a robustness study where model errors are introduced to verify its good performance. After verification of controller performance, some process changes were proposed in order to improve process productivity and polymer quality. Finally, the optimal temperature profile and optimal feed policies of the monomer and initiator, obtained in a dynamic optimization step, are used to provide the optimal set points for the nonlinear control. The results show that the nonlinear controller designed here is appropriate to follow the optimal temperature trajectories calculated previously
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De, Queiroz Lima Roberta. "Modeling and simulation in nonlinear stochastic dynamic of coupled systems and impact." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1049/document.
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Dans cette Thèse, la conception robuste avec un modèle incertain d'un système électromécanique avec vibro-impact est fait. Le système électromécanique est constitué d'un chariot, dont le mouvement est excité par un moteur à courant continu et un marteau embarqué dans ce chariot. Le marteau est relié au chariot par un ressort non linéaire et par un amortisseur linéaire, de façon qu'un mouvement relatif existe entre eux. Une barrière flexible linéaire, placé à l'extérieur du chariot limite les mouvements de marteau. En raison du mouvement relatif entre le marteau et la barrière, impacts peuvent se produire entre ces deux éléments. Le modèle du système développé prend en compte l'influence du courant continu moteur dans le comportement dynamique du système. Certains paramètres du système sont incertains, tels comme les coefficients de rigidité et d'amortissement de la barrière flexible. L'objectif de la Thèse est de réaliser une optimisation de ce système électromécanique par rapport aux paramètres de conception afin de maximiser l'impact puissance sous la contrainte que la puissance électrique consommée par le moteur à courant continu est inférieure à une valeur maximale. Pour choisir les paramètres de conception dans le problème d'optimisation, une analyse de sensibilité a été réalisée afin de définir les paramètres du système les plus sensibles. L'optimisation est formulée dans le cadre de la conception robuste en raison de la présence d'incertitudes dans le modèle. Les lois de probabilités liées aux variables aléatoires du problème sont construites en utilisant le Principe du Maximum l'Entropie et les statistiques de la réponse stochastique du système sont calculées en utilisant la méthode de Monte Carlo. L'ensemble d'équations non linéaires sont présentés, et un solveur temporel adapté est développé. Le problème d'optimisation non linéaire stochastique est résolu pour différents niveaux d'incertitudes, et aussi pour le cas déterministe. Les résultats sont différents, ce qui montre l'importance de la modélisation stochastiqueIn this Thesis, the robust design with an uncertain model of a vibro-impact electromechanical system is done. The electromechanical system is composed of a cart, whose motion is excited by a DC motor (motor with continuous current), and an embarked hammer into this cart. The hammer is connected to the cart by a nonlinear spring component and by a linear damper, so that a relative motion exists between them. A linear flexible barrier, placed outside of the cart, constrains the hammer movements. Due to the relative movement between the hammer and the barrier, impacts can occur between these two elements. The developed model of the system takes into account the influence of the DC motor in the dynamic behavior of the system. Some system parameters are uncertain, such as the stiffness and the damping coefficients of the flexible barrier. The objective of the Thesis is to perform an optimization of this electromechanical system with respect to design parameters in order to maximize the impact power under the constraint that the electric power consumed by the DC motor is lower than a maximum value. To chose the design parameters in the optimization problem, an sensitivity analysis was performed in order to define the most sensitive system parameters. The optimization is formulated in the framework of robust design due to the presence of uncertainties in the model. The probability distributions of random variables are constructed using the Maximum Entropy Principle and statistics of the stochastic response of the system are computed using the Monte Carlo method. The set of nonlinear equations are presented, and an adapted time domain solver is developed. The stochastic nonlinear constrained design optimization problem is solved for different levels of uncertainties, and also for the deterministic case. The results are different and this show the importance of the stochastic modeling
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Stockton, Nicklas O. "Hybrid Genetic Fuzzy Systems for Control of Dynamic Systems." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1523635312922039.
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Schön, Thomas B. "Estimation of Nonlinear Dynamic Systems : Theory and Applications." Doctoral thesis, Linköpings universitet, Reglerteknik, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-7124.
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This thesis deals with estimation of states and parameters in nonlinear and non-Gaussian dynamic systems. Sequential Monte Carlo methods are mainly used to this end. These methods rely on models of the underlying system, motivating some developments of the model concept. One of the main reasons for the interest in nonlinear estimation is that problems of this kind arise naturally in many important applications. Several applications of nonlinear estimation are studied. The models most commonly used for estimation are based on stochastic difference equations, referred to as state-space models. This thesis is mainly concerned with models of this kind. However, there will be a brief digression from this, in the treatment of the mathematically more intricate differential-algebraic equations. Here, the purpose is to write these equations in a form suitable for statistical signal processing. The nonlinear state estimation problem is addressed using sequential Monte Carlo methods, commonly referred to as particle methods. When there is a linear sub-structure inherent in the underlying model, this can be exploited by the powerful combination of the particle filter and the Kalman filter, presented by the marginalized particle filter. This algorithm is also known as the Rao-Blackwellized particle filter and it is thoroughly derived and explained in conjunction with a rather general class of mixed linear/nonlinear state-space models. Models of this type are often used in studying positioning and target tracking applications. This is illustrated using several examples from the automotive and the aircraft industry. Furthermore, the computational complexity of the marginalized particle filter is analyzed. The parameter estimation problem is addressed for a relatively general class of mixed linear/nonlinear state-space models. The expectation maximization algorithm is used to calculate parameter estimates from batch data. In devising this algorithm, the need to solve a nonlinear smoothing problem arises, which is handled using a particle smoother. The use of the marginalized particle filter for recursive parameterestimation is also investigated. The applications considered are the camera positioning problem arising from augmented reality and sensor fusion problems originating from automotive active safety systems. The use of vision measurements in the estimation problem is central to both applications. In augmented reality, the estimates of the camera’s position and orientation are imperative in the process of overlaying computer generated objects onto the live video stream. The objective in the sensor fusion problems arising in automotive safety systems is to provide information about the host vehicle and its surroundings, such as the position of other vehicles and the road geometry. Information of this kind is crucial for many systems, such as adaptive cruise control, collision avoidance and lane guidance.
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Chan, Chung Ying Amy. "Dynamic modeling, control and simulation of a planar five-link bipedal walking system." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0020/MQ53135.pdf.
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Ajayi, Michael Oluwatosin. "Modelling and control of actuated lower limb exoskeletons : a mathematical application using central pattern generators and nonlinear feedback control techniques." Thesis, Paris Est, 2016. http://www.theses.fr/2016PESC1021/document.
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Les exosquelettes représentent des systèmes mécaniques portables qui ont reçu une grande attention de la part de la communauté scientifique ces derrières années, vues les possibilités qu'ils offrent.Ces possibilités concernent principalement les fonctions d'assistance et de réhabilitation des personnes en situation de handicape et personnes âgées, dans un objectif de leur permettre de recouvrir leur facultés motrices. Cependant, d'autres possibilités sont concernées comme permettre à des personnes paraplégiques de remarcher ou de permettre des opérations de manipulation excédent les capacités humaines.Pour permettre la réalisation des fonctions offertes par les robots portables, une connaissance fine de la dynamique du système est requise en relation avec les tâches à réaliser par les sujets. Par ailleurs, des approches de commande sûres qui prennent en compte la sécurité des usagers est nécessaire. Dans cet objectif, des techniques de commande bio-inspirées avec des techniques de commande par découplage non-linéaire sont considérées. Les dernières assurent que la loi de commande est stable et bornée en prenant en considération le domaine de saturation des actionneurs alors que les premières ont inspiré la conception de contrôleurs basés sur les oscillateurs locaux non-linéaires (Central Pattern Generators : CPG).Les CPGs sont modélisés par des réseaux de neurones qui peuvent être représentés par un ensemble d'oscillateurs non-linéaires situés dans la moelle épinière, avec des capacités de génération de signaux rythmiques multidimensionnels synchrones pour remplir des fonctions motrices sous le contrôle de simples signaux de commande. Ces signaux sont supposés être de nature périodique ou semi-périodique, dont la génération pour étudier les systèmes de locmotion humain reste un problème de recherche d'actualité.Dans la présente thèse, l'analyse, la simulation et la commandes des articulations d'un robot portable utilisé pour les membres inférieurs en utilisant, d'un côté les oscillateurs locaux non-linéaires et d'un autre côté des techniques de commande par découplage non-linéaire sont proposés, avec comme objectif final de permtre la mise en œuvre des approches proposées sur la plate-forme expérimentale développée au sein du FSATI (French South African Institute fo Technology).Pour atteindre l'objectif qui a été fixé par les travaux de recherche engagés, une étude de l'état de l'art sur les aspects liés à la connaissance de l'anatomie, la physiologie et l'analyse biomécanique de la marche humaine a été effectuée. Par ailleurs, une étude détaillée des oscillateurs locaux non-linéaires en parallèle avec les approches de commande directe et inverse, ont permis la proposition de stratégies de commande qui couplent les oscillateurs non-linéaires d'un côté et des techniques de découplage non-linéaire d'un autre côté ont été proposées et validées sur des systèmes de plusieurs degrés de liberté. Des simulations intensives ont été conduites afin de vérifier la capacité d'adaptation temps des approches de commandes mises en œuvre avec l'humain ans la boucle.Les contributions de la présente étude concerne deux approches de commande. La première approche concerne l'intégration d'une approche bio-inspirée, basée sur les oscillateurs locaux non-linéaires et la deuxième approche est basée sur les techniques de commande bornée par découplage non-linéaireWearable robotic system has become a well sought after mechanism in the field of biomechatronics engineering due to the the various possibilities it possess. These possibilities encompass the assistive and rehabilitative protocols rendered to disabled and elderly people, in order to enable them regain control of their limbs and of course increase the abilities of able-bodied persons. It therefore clearly drives the motive of bringing back paraplegics back on their feet as well as executing difficult task beyond human ability.Achieving the intended function of wearable robots requires the model dynamics of the physical system in relation to the tasks required to be performed by subjects. This demands a proper control measure which takes into account the safety of the wearer. For this purpose, bio-inspired control techniques and bounded nonlinear feedback controllers are considered. The latter control design ensures that the stipulated power required is not exceeded as well as the saturation of the actuator, while the former motivates the design of controllers based on the concept of Central Pattern Generators (CPG). CPGs are characterised as biological neural networks which can be represented by a set of coupled nonlinear oscillator situated in the spinal cord of mammals, having the capability of generating coordinated multidimensional rhythmic signals for the purpose of locomotion, under the control of simple input signals. These rhythmic signals are termed to be periodic or quasi-periodic in nature, hence performing this task in robotics and animal motor control has been a perpetual research problem. The movement of the lower limb of humans thus present a platform to investigate and address this difficulty.In this thesis, the analysis, simulation, and control of joints which relate to the human lower limbs via CPGs and feedback control techniques are investigated with an aim of practically implementing the control strategies using a lower limb exoskeleton is presented. To accomplish this goal, it is expedient to have comprehensive knowledge of the anatomy, physiology and the normal gait biomechanics of the human lower limbs. Understanding the theories, principles and mathematical background of nonlinear oscillators are also required. Control strategies using the inverse and the forward dynamics approach based on different types of coupled nonlinear oscillators and nonlinear feedback control techniques were considered for single/multiple degrees of freedom (DoF). Simulations and results were presented to verify the controller-human system ability to constantly and dynamically track and readapt its control parameters to maintain its desired motion dynamics, with reduced control torque values.This work basically deals with two distinct method of control systems; one which integrates bio-inspired methods with classical and nonlinear control techniques to govern the exoskeletons' joints with a human in the loop, and another which utilises bounded nonlinear feedback control techniques for same purpose
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McEwen, Matthew D. "Dynamic system identification and modeling of a rotary wing UAV for stability and control analysis." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA349878.
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Levashov, Michael Yurievich. "Modeling, system identication, and control for dynamic locomotion of the LittleDog robot on rough terrain." Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/71273.
Full textAbstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2012.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student submitted PDF version of thesis.
Includes bibliographical references (p. 76-80).
In this thesis, I present a framework for achieving a stable bounding gait on the LittleDog robot over rough terrain. The framework relies on an accurate planar model of the dynamics, which I assembled from a model of the motors, a rigid body model, and a novel physically-inspired ground interaction model, and then identied using a series of physical measurements and experiments. I then used the RG-RRT algorithm on the model to generate bounding trajectories of LittleDog over a number of sets of rough terrain in simulation. Despite signicant research in the field, there has been little success in combining motion planning and feedback control for a problem that is as kinematically and dynamically challenging as LittleDog. I have constructed a controller based on transverse linearization and used it to stabilize the planned LittleDog trajectories in simulation. The resulting controller reliably stabilized the planned bounding motions and was relatively robust to signicant amounts of time delays in estimation, process and estimation noise, as well as small model errors. In order to estimate the state of the system in real time, I modified the EKF algorithm to compensate for varying delays between the sensors. The EKF-based filter works reasonably well, but when combined with feedback control, simulated delays, and the model it produces unstable behavior, which I was not able to correct. However, the close loop simulation closely resembles the behavior of the control and estimation on the real robot, including the failure modes, which suggests that improving the feedback loop might result in bounding on the real LittleDog. The control framework and many of the methods developed in this thesis are applicable to other walking systems, particularly when operating in the underactuated regime.
by Michael Yurievich Levashov.
S.M.
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Chau, Wan-hin Derek, and 鄒允軒. "Modeling and solving decentralized supply chain management problems using multi-agent system with dynamic-control agents." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2015. http://hdl.handle.net/10722/208622.
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Managing large scale supply chains are never an easy task. Numerous researches have put emphasis on supply chain modeling and optimization to assist businesses in searching for the best practices so as to endure the extremely competitive business landscape. To some, the paradigm of centralized supply chain management is adequate for solving its strategic and operational problems. Yet with the improper use of authoritative assumptions, the efficiency of the management process is often jeopardized. Furthermore, current researches in decentralized supply chain are mostly focused on dyadic or linear relationship and seldom consider quantitative modeling and analysis with scalability. Recent development in multi-agent systems provided a means for such a modeling methodology and hence researches in this area. To enhance model representativeness and computational efficiency, vision-based control models that are able to simulate individual operational and strategic traits are developed. In this research, pyramidal agent alignment is proposed for simulating the management-operation dimension with regards to decision exercising and bargaining power management. The system offers one thousand supply chain agents that are simulated in a mono-layer, multi-tier network in real time. Stochastic and dynamic behaviors of the network are handled by statistical regression on scenario-based model evaluation. The proposed design enabled grand scale supply chain modeling and optimization that follows a general or custom simulation supported optimization architecture. Network governance problems and dynamic steering problems are considered and solved using genetic algorithm and dynamic programming. The thesis looks into the potential benefits and limitations of the proposed methods in details, and future research directions are discussed.published_or_final_version
Industrial and Manufacturing Systems Engineering
Doctoral
Doctor of Philosophy
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Herrera, Cáceres Carlos Antonio. "Modeling and predictive control of a cash concentration and disbursements system." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399516.
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Esta tesis aborda el estudio de la Planificación financiera a corto plazo y la Gerencia de efectivo, a través del movimiento de dinero en las cuentas bancarias que participan en las decisiones financieras importantes de una empresa. La investigación se realiza en el marco de los modelos de planificación financiera corporativa, cuyo desarrollo se ha producido sobre todo en los últimos sesenta años. En particular, el trabajo se enfoca en los Sistemas de concentración de caja y desembolsos (CCDS), utilizados por las empresas para mejorar la planificación y el control de los activos corrientes y la Gerencia de efectivo. El objetivo de un CCDS es concentrar el efectivo disponible en una cuenta bancaria principal para hacer el mejor uso del dinero en grandes cantidades y, así, apoyar las operaciones de inversión y financiamiento. En consecuencia, la motivación principal de la tesis es lograr una representación exacta de un CCDS que permite su simulación numérica, análisis y evaluación, así como la posibilidad de nuevas investigaciones y el desarrollo de algoritmos para el soporte de decisiones financieras, basados en herramientas de la teoría de control. En este sentido, se presenta un modelo de simulación de un CCDS basado en ecuaciones en diferencias y técnicas de ingeniería de sistemas, incluyendo la existencia de retardos. Se supone la existencia de una cuenta principal operada de forma centralizada. La cual recibe transferencias de dinero desde las cuentas de ingreso de cada agencia de la empresa. También desde la cuenta principal, el dinero se transfiere hacia las cuentas de desembolso de las agencias para cubrir los sobregiros. El CCDS incluye también una cuenta de inversión para aprovechar los excedentes de efectivo y una línea de crédito para cubrir los déficits de caja. Adicionalmente, se deriva un modelo equivalente representado por ecuaciones algebraicas usando la transformada Z, posibilitando el uso de técnicas rigurosas de control en el campo financiero.
Bajo un enfoque descentralizado sobre el modelo del CCDS, se desarrolla un modelo de control predictivo (MPC) para una cuenta de ingresos, cuya aplicación se extiende a todas las agencias del sistema. Se utiliza Programación dinámica (DP) para el modelo de predicción que, a su vez, incluye un modelo de pronóstico estándar para la incertidumbre. EL MPC se simplifica procurando aliviar algunos de los problemas conocidos cuando DP se aplica bajo incertidumbre. También, se establece un sistema de bandas para la incertidumbre, limitando la entrada del modelo de DP, junto con un regulador de estabilización en forma de cascada que utiliza una ganancia de realimentación lineal. Esta combinación permite determinar un intervalo para la estabilidad del sistema indistintamente del tamaño del horizonte de predicción. La señal de referencia es una función de diente de sierra, que se adapta convenientemente a la política de inventario aplicada. La tesis muestra, en teoría y por medio de simulaciones, que el controlador propuesto cumple su objetivo. Por otra parte, se realiza una adaptación del MPC de la cuenta de ingresos, agregándole tiempo de retardo al modelo, con el propósito de utilizarlo para el control de las cuentas de desembolso. En consecuencia, se ofrecen dos propuestas de MPC para el problema de la cobertura de sobregiro. Por último, se presenta un caso de estudio utilizando datos hipotéticos para probar el modelo de simulación del CCDS. La ejecución del modelo ha permitido realizar un análisis exhaustivo de los resultados mostrando sus potencialidades y la versatilidad para adaptarse a diferentes escenarios realistas. Esta investigación abre un abanico de posibilidades para futuras investigaciones en las que se combinan las técnicas y teorías de la ingeniería de sistemas y de control, aplicados al ámbito financiero corporativo.This thesis addresses the study of cash management and short-term financial planning through the movement of money in bank accounts involved in the important financial decisions of a firm. The research is carried within the framework of models for corporate financial planning, whose development has mostly occurred in the last sixty years. Particularly, the work focuses on the Cash Concentration and Disbursements Systems (CCDS), which are used by firms for the purpose of improving the planning and control of current assets and cash management. The aim of a CCDS is to concentrate available cash in a main bank account in order to make best use of money in large amounts to support investment and financing operations. Consequently, the main motivation of the thesis is to achieve an accurate representation of a CCDS, allowing its numerical simulation, analysis and evaluation, as well as the subsequent possibility of exploring new researches and the development of algorithms for the financial decisions support, based on tools of control theory. In this regard, a simulation model of a CCDS seen as an inventory management system is presented, based on difference equations and systems engineering techniques including the existence of delays due to banking procedures. The model assumes the existence of a centrally operated main account. This account receives money transfers from the revenue accounts of each agency. Also from the main account, money is transferred to the agencies' disbursements accounts in order to cover overdrafts. There exist an investment account into which any cash surpluses of the main account are deposited and a credit line in order to avoid the cash deficits. The operating rules for the CCDS are defined, and income and financial costs involved are considered. The model represents the flow of money between the identified elements of the system and the flow of money requirements or transfer orders. An equivalent model represented by algebraic equations through the Z-transform is derived, which allows using rigorous control techniques in the field of finance. Based on a decentralized approach on the model of the CCDS, a Model Predictive Control (MPC) for a revenue account is developed, which is applied to all agencies. Dynamic Programming (DP) is used for the prediction model by including a standard forecasting model for uncertainty. Simplifications of the MPC are included seeking alleviate some of the known problems when DP is applied under uncertainty. Moreover, a band for the uncertainty is established to narrow the input of the DP model, together with a stabilizing regulator in cascade fashion using a linear feedback gain (closed-loop). This combination allows determining a range for the system stability regardless of the size of the prediction horizon. The reference signal used is a sawtooth function, which conveniently adapts to the inventory policy applied. Theoretically, and through simulation, it is shown that the proposed controller meets the control objective. The MPC of the revenue account is adapted by adding delay time in order to be used for disbursement accounts. Accordingly, two proposals of a model predictive control are provided on the overdraft coverage problem. Finally, a case study is presented using hypothetical data in order to test the simulation model of the CCDS. Running the model allows performing a comprehensive analysis of results showing its potentialities and the versatility to suit different realistic scenarios. This research opens up a range of possibilities for further research in which techniques and theories of systems engineering and control are combined, applied to corporate financial field.
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Skolthanarat, Siriya. "The Modeling and Control of a Wind Farm and Grid Interconnection in a multi-machine system." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/28920.
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This dissertation focuses on the modeling and control of WECS (Wind Energy Conversion System) in a multi-machine system. As one of the fastest growing renewable energy resources, the trend of wind energy changes to variable speed wind turbines. The concept of the variable speed is based on the variable speed according to the instantaneous wind speed of wind turbines. Since the utility grid requires the stable frequency and magnitude voltages, there must be grid interconnection of the wind farm and the utility grid. The grid interconnection must support the concept of the variable speed wind turbines. Since each wind turbine locates in a different location in a wind site, it receives the different wind speed. Hence the grid interconnection must convert the variable frequency and magnitude output voltages of the wind turbines to a synchronous frequency and magnitude voltages associated to the grid.
With the new technologies of power semiconductor devices, the power converter can operate with high voltage, high current, and high switching frequency. This results in a higher power capacity of a wind farm. Nonetheless, the power converters generate harmonic distortions to the utility grid. The harmonic distortions components in the voltages and currents of the grid degrade the power quality. This results in the damage of electrical components in the power system such as capacitor banks, inductors, protection devices, etc. The harmonic distortions can be reduced with the technology of the multi-level inverter. It is required that the wind energy provides the real and reactive power control for frequency and voltage stability. In order to achieve the power control, the modeling and control of the power electronic grid interconnection is presented in this dissertation.
The grid interconnection is modeled with linearization techniques. The models in frequency domain in the form of transfer functions are used to design the compensators in the control system. The model is considered as a SISO (Single Input Single Output) system to design the compensators in SISO tool of MATLAB. The selected control system is current control that can control the real and reactive powers independently. Furthermore, since the grid interconnection is modeled separately for each sub-system, the control system is verified with integration of the sub-systems. The grid interconnection is modeled in Simulink and simulated in the PSCAD.
In reality, the power system is comprised of multi-machines. They affect the power system stability, reliability, and quality. The dynamic modeling of an aggregated wind farm with synchronous generator and grid interconnection in a multi-machine system is presented. The test system is a 10-bus system with three generators and three loads. The dynamic modeling involves the power flow calculations that determine the equilibrium points of the system. The system is modeled with differential equations of wind turbines, synchronous generators, and grid interconnection. The system is modeled in the time domain in state space form. The system characteristics can be determined by poles or eigen values obtained from the characteristic equations. Since the system is MIMO (Multi Input Multi Output) system, the optimal control theory is used to reduce the deviation of system behaviors during disturbances. The LQR (Linear Quadratic Regulator) is utilized to control the system with eigen value assignment method. Simulation results in Simulink are illustrated.Ph. D.
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Bärlund, Alexander. "Nonlinear MPC for Motion Control and Thruster Allocation of Ships." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-158493.
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Critical automated maneuvers for ships typically require a redundant set of thrusters. The motion control system hierarchy is commonly separated into several layers using a high-level motion controller and a thruster allocation (TA) algorithm. This allows for a modular design of the software where the high-level controller can be designed without comprehensive information on the thrusters, while detailed issues such as input saturation and rate limits are handled by the TA. However, for a certain set of thruster configurations this decoupling may result in poor control performance due to the limited knowledge in the high-level controller about the physical limitations of the ship and the behavior of the TA. This thesis investigates different approaches of improving the control performance, using nonlinear Model Predictive Control (MPC) as a foundation for the developed motion controllers due to its optimized solution and capability of satisfying constraints. First, a decoupled system is implemented and results are provided for two simple motion tasks showing problems related to the decoupling. Thereafter, two different approaches are taken to remedy the observed drawbacks. A nonlinear MPC controller is developed combining the motion controller and thruster allocation resulting in a more robust control system. Then, in order to keep the control system modularized, an investigation of possible ways to augment the decoupled system so as to achieve similar performance as the combined system is carried out. One proposed solution is a nonlinear MPC controller with time-varying constraints accounting for the current limitations of the thruster system. However, this did not always improve the control performance since the behavior of the TA still is unknown to the MPC controller.
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Chen, Yutao. "Algorithms and Applications for Nonlinear Model Predictive Control with Long Prediction Horizon." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3421957.
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Fast implementations of NMPC are important when addressing real-time control of systems exhibiting features like fast dynamics, large dimension, and long prediction horizon, as in such situations the computational burden of the NMPC may limit the achievable control bandwidth.
For that purpose, this thesis addresses both algorithms and applications.
First, fast NMPC algorithms for controlling continuous-time dynamic systems using a long prediction horizon have been developed.
A bridge between linear and nonlinear MPC is built using partial linearizations or sensitivity update. In order to update the sensitivities only when necessary, a Curvature-like measure of nonlinearity (CMoN) for dynamic systems has been introduced and applied to existing NMPC algorithms. Based on CMoN, intuitive and advanced updating logic have been developed for different numerical and control performance. Thus, the CMoN, together with the updating logic, formulates a partial sensitivity updating scheme for fast NMPC, named CMoN-RTI. Simulation examples are used to demonstrate the effectiveness and efficiency of CMoN-RTI. In addition, a rigorous analysis on the optimality and local convergence of CMoN-RTI is given and illustrated using numerical examples.
Partial condensing algorithms have been developed when using the proposed partial sensitivity update scheme. The computational complexity has been reduced since part of the condensing information are exploited from previous sampling instants. A sensitivity updating logic together with partial condensing is proposed with a complexity linear in prediction length, leading to a speed up by a factor of ten.
Partial matrix factorization algorithms are also proposed to exploit partial sensitivity update. By applying splitting methods to multi-stage problems, only part of the resulting KKT system need to be updated, which is computationally dominant in on-line optimization. Significant improvement has been proved by giving floating point operations (flops).
Second, efficient implementations of NMPC have been achieved by developing a Matlab based package named MATMPC. MATMPC has two working modes: the one completely relies on Matlab and the other employs the MATLAB C language API. The advantages of MATMPC are that algorithms are easy to develop and debug thanks to Matlab, and libraries and toolboxes from Matlab can be directly used. When working in the second mode, the computational efficiency of MATMPC is comparable with those software using optimized code generation. Real-time implementations are achieved for a nine degree of freedom dynamic driving simulator and for multi-sensory motion cueing with active seat.Implementazioni rapide di NMPC sono importanti quando si affronta il controllo in tempo reale di sistemi che presentano caratteristiche come dinamica veloce, ampie dimensioni e orizzonte di predizione lungo, poiché in tali situazioni il carico di calcolo dell'MNPC può limitare la larghezza di banda di controllo ottenibile. A tale scopo, questa tesi riguarda sia gli algoritmi che le applicazioni. In primo luogo, sono stati sviluppati algoritmi veloci NMPC per il controllo di sistemi dinamici a tempo continuo che utilizzano un orizzonte di previsione lungo. Un ponte tra MPC lineare e non lineare viene costruito utilizzando linearizzazioni parziali o aggiornamento della sensibilità. Al fine di aggiornare la sensibilità solo quando necessario, è stata introdotta una misura simile alla curva di non linearità (CMoN) per i sistemi dinamici e applicata agli algoritmi NMPC esistenti. Basato su CMoN, sono state sviluppate logiche di aggiornamento intuitive e avanzate per diverse prestazioni numeriche e di controllo. Pertanto, il CMoN, insieme alla logica di aggiornamento, formula uno schema di aggiornamento della sensibilità parziale per NMPC veloce, denominato CMoN-RTI. Gli esempi di simulazione sono utilizzati per dimostrare l'efficacia e l'efficienza di CMoN-RTI. Inoltre, un'analisi rigorosa sull'ottimalità e sulla convergenza locale di CMoN-RTI viene fornita ed illustrata utilizzando esempi numerici. Algoritmi di condensazione parziale sono stati sviluppati quando si utilizza lo schema di aggiornamento della sensibilità parziale proposto. La complessità computazionale è stata ridotta poiché parte delle informazioni di condensazione sono sfruttate da precedenti istanti di campionamento. Una logica di aggiornamento della sensibilità insieme alla condensazione parziale viene proposta con una complessità lineare nella lunghezza della previsione, che porta a una velocità di un fattore dieci. Sono anche proposti algoritmi di fattorizzazione parziale della matrice per sfruttare l'aggiornamento della sensibilità parziale. Applicando metodi di suddivisione a problemi a più stadi, è necessario aggiornare solo parte del sistema KKT risultante, che è computazionalmente dominante nell'ottimizzazione online. Un miglioramento significativo è stato dimostrato dando operazioni in virgola mobile (flop). In secondo luogo, sono state realizzate implementazioni efficienti di NMPC sviluppando un pacchetto basato su Matlab chiamato MATMPC. MATMPC ha due modalità operative: quella si basa completamente su Matlab e l'altra utilizza l'API del linguaggio MATLAB C. I vantaggi di MATMPC sono che gli algoritmi sono facili da sviluppare e eseguire il debug grazie a Matlab e le librerie e le toolbox di Matlab possono essere utilizzate direttamente. Quando si lavora nella seconda modalità, l'efficienza computazionale di MATMPC è paragonabile a quella del software che utilizza la generazione di codice ottimizzata. Le realizzazioni in tempo reale sono ottenute per un simulatore di guida dinamica di nove gradi di libertà e per il movimento multisensoriale con sedile attivo.
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Arsava, Kemal Sarp. "Modeling, Control and Monitoring of Smart Structures under High Impact Loads." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-dissertations/105.
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In recent years, response analysis of complex structures under impact loads has attracted a great deal of attention. For example, a collision or an accident that produces impact loads that exceed the design load can cause severe damage on the structural components. Although the AASHTO specification is used for impact-resistant bridge design, it has many limitations. The AASHTO specification does not incorporate complex and uncertain factors. Thus, a well-designed structure that can survive a collision under specific conditions in one region may be severely damaged if it were impacted by a different vessel, or if it were located elsewhere with different in-situ conditions. With these limitations in mind, we propose different solutions that use smart control technology to mitigate impact hazard on structures. However, it is challenging to develop an accurate mathematical model of the integrated structure-smart control systems. The reason is due to the complicated nonlinear behavior of the integrated nonlinear systems and uncertainties of high impact forces. In this context, novel algorithms are developed for identification, control and monitoring of nonlinear responses of smart structures under high impact forces. To evaluate the proposed approaches, a smart aluminum and two smart reinforced concrete beam structures were designed, manufactured, and tested in the High Impact Engineering Laboratory of Civil and Environmental Engineering at WPI. High-speed impact force and structural responses such as strain, deflection and acceleration were measured in the experimental tests. It has been demonstrated from the analytical and experimental study that: 1) the proposed system identification model predicts nonlinear behavior of smart structures under a variety of high impact forces, 2) the developed structural health monitoring algorithm is effective in identifying damage in time-varying nonlinear dynamic systems under ambient excitations, and 3) the proposed controller is effective in mitigating high impact responses of the smart structures.
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Almeida, Rynaldo Zanotele Hemerly de. "Modelagem dinâmica e controle de robô manipulador de arquitetura paralela assimétrica de três graus de liberdade." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-19092014-113652/.
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Este trabalho trata da modelagem dinâmica e do projeto de sistemas de controle para um robô manipulador de arquitetura paralela assimétrica de três graus de liberdade, correspondente a três translações de seu efetuador no espaço tridimensional, concebido para tarefas de pega-e-põe (pick-and-place). Dentre os desenvolvimentos teóricos, procurou-se estender, para toda gama de robôs paralelos e topologicamente assimétricos, a abrangência dos procedimentos aplicados inicialmente a este caso específico. Foram empregados o Método de Lagrange e o Princípio dos Trabalhos Virtuais na obtenção de modelos dinâmicos baseados em hipóteses simplificadoras de corpos rígidos de massas concentradas e de massas distribuídas. Para o projeto de controladores, foram utilizadas as técnicas de torque computado e torque computado estendido. As formulações correspondentes a estas técnicas foram aprimoradas de forma a permitir o cálculo de esforços de controle de modo equivalente tanto nas coordenadas dos atuadores como nas coordenadas do efetuador e em conformidade com os requisitos de resposta dinâmica definidos para o robô. Tais requisitos podem ser inclusive anisotrópicos, o que se julga ser mais apropriado para robôs paralelos assimétricos. Particularmente em relação ao robô analisado, foram avaliados efeitos de simplificação do modelo dinâmico e da discretização do controlador (incluindo discretização com dupla frequência de amostragem) sobre os erros de controle de posição. Percebeu-se que os requisitos de alto desempenho das tarefas de pega-epõe levam o projeto do controlador ao limite de validade da hipótese simplificadora de corpo rígido e da capacidade de processamento do hardware de controle.This work deals with the dynamic modeling and the design of control systems for an asymmetric parallel manipulator robot with three degrees of freedom, related to three translations of its end-effector in the tridimensional space, conceived for pick-andplace tasks. Among the theoretical developments, one of them was the extension of the proposed procedures, initially applied to this specific case, to the whole class of topologically asymmetric and parallel mechanisms. The Lagrange Method and the Principle of Virtual work were employed in order to build dynamic models based on rigid body assumption with either lumped or distributed mass simplification hypothesis. For the controllers design, computed torque and extended computed torque techniques were used. The formulations of such techniques were elaborated in order to allow the calculation of the control efforts to be executed equivalently both on the actuators coordinates and on the end-effector coordinates, in accordance with the dynamic response requirements defined for the robot. These requirements may be even anisotropic, what is considered to be more suitable for asymmetric parallel robots. Particularly about the analyzed robot, the effects of dynamic model simplification and controller discretization (including double sample rate discretization) on the position control errors were evaluated. It was realized that the high performance requirements for pick-and-place tasks push the controller design to the limit of validity of the rigid body assumption and of the control hardware processing capacity.
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Tugsal, Umut. "FAULT DIAGNOSIS OF ELECTRONIC FUEL CONTROL (EFC) VALVES VIA DYNAMIC PERFORMANCE TEST METHOD." ProQuest, 2009. http://hdl.handle.net/1805/2094.
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Indiana University-Purdue University Indianapolis (IUPUI)Electronic Fuel Control (EFC) valve regulates fuel flow to the injector fuel supply line in the Cummins Pressure Time (PT) fuel system. The EFC system controls the fuel flow by means of a variable orifice that is electrically actuated. The supplier of the EFC valves inspects all parts before they are sent out. Their inspection test results provide a characteristic curve which shows the relationship between pressure and current provided to the EFC valve. This curve documents the steady state characteristics of the valve but does not adequately capture its dynamic response. A dynamic test procedure is developed in order to evaluate the performance of the EFC valves. The test itself helps to understand the effects that proposed design changes will have on the stability of the overall engine system. A by product of this test is the ability to evaluate returned EFC valves that have experienced stability issues. The test determines whether an EFC valve is faulted or not before it goes out to prime time use. The characteristics of a good valve and bad valve can be observed after the dynamic test. In this thesis, a mathematical model has been combined with experimental research to investigate and understand the behavior of the characteristics of different types of EFC valves. The model takes into account the dynamics of the electrical and mechanical portions of the EFC valves. System Identification has been addressed to determine the transfer functions of the different types of EFC valves that were experimented. Methods have been used both in frequency domain as well as time domain. Also, based on the characteristic patterns exhibited by the EFC valves, fuzzy logic has been implemented for the use of pattern classification.
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Moberg, Stig. "On Modeling and Control of Flexible Manipulators." Licentiate thesis, Linköping University, Linköping University, Automatic Control, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10463.
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Industrial robot manipulators are general-purpose machines used for industrial automation in order to increase productivity, flexibility, and quality. Other reasons for using industrial robots are cost saving, and elimination of heavy and health-hazardous work. Robot motion control is a key competence for robot manufacturers, and the current development is focused on increasing the robot performance, reducing the robot cost, improving safety, and introducing new functionalities. Therefore, there is a need to continuously improve the models and control methods in order to fulfil all conflicting requirements, such as increased performance for a robot with lower weight, and thus lower mechanical stiffness and more complicated vibration modes. One reason for this development of the robot mechanical structure is of course cost-reduction, but other benefits are lower power consumption, improved dexterity, safety issues, and low environmental impact.
This thesis deals with three different aspects of modeling and control of flexible, i.e., elastic, manipulators. For an accurate description of a modern industrial manipulator, the traditional flexible joint model, described in literature, is not sufficient. An improved model where the elasticity is described by a number of localized multidimensional spring-damper pairs is therefore proposed. This model is called the extended flexible joint model. This work describes identification, feedforward control, and feedback control, using this model.
The proposed identification method is a frequency-domain non-linear gray-box method, which is evaluated by the identification of a modern six-axes robot manipulator. The identified model gives a good description of the global behavior of this robot.
The inverse dynamics control problem is discussed, and a solution methodology is proposed. This methodology is based on a differential algebraic equation (DAE) formulation of the problem. Feedforward control of a two-axes manipulator is then studied using this DAE approach.
Finally, a benchmark problem for robust feedback control of a single-axis extended flexible joint model is presented and some proposed solutions are analyzed.
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Dugan, Sean Patrick-Michael. "On the Design, Modeling, and Control of a Hybrid Pump System for Dynamic Pressurization of Explanted Mammalian Hearts." NCSU, 2007. http://www.lib.ncsu.edu/theses/available/etd-10242007-103805/.
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A hybrid electromechanical pump system is proposed to mimic left ventricular blood pressure in a living mammalian heart. The system consists of a gear pump and voice coil actuated diaphragm (VCAD) pump connected in parallel. By combining a high-capacity, low-bandwidth gear pump with a low-capacity, high-bandwidth VCAD pump, the advantages of both can be realized, resulting in an economical high-bandwidth pumping system that may be used with animal hearts of arbitrary size. Mathematical models are developed to describe the system dynamics and develop a digital controller. Experimental results are also presented.
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Sun, Liang. "Dynamic Modeling, Trajectory Generation and Tracking for Towed Cable Systems." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3532.
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In this dissertation, we focus on the strategy that places and stabilizes the path of an aerial drogue, which is towed by a mothership aircraft using a long flexible cable, onto a horizontally flat orbit by maneuvering the mothership in the presence of wind. To achieve this goal, several studies for towed cable systems are conducted, which include the dynamic modeling for the cable, trajectory generation strategies for the mothership, trajectory-tracking control law design, and simulation and flight test implementations. First, a discretized approximation method based on finite element and lumped mass is employed to establish the mathematical model for the towed cable system in the simulation. Two approaches, Gauss's Principle and Newton's second law, are utilized to derive the equations of motion for inelastic and elastic cables, respectively. The preliminary studies for several key parameters of the system are conducted to learn their sensitivities to the system motion in the steady state. Flight test results are used to validate the mathematical model as well as to determine an appropriate number of cable links. Furthermore, differential flatness and model predictive control based methods are used to produce a mothership trajectory that leads the drogue onto a desired orbit. Different desired drogue orbits are utilized to generate required mothership trajectories in different wind conditions. The trajectory generation for a transitional flight in which the system flies from a straight and level flight into a circular orbit is also presented. The numerical results are presented to illustrate the required mothership orbits and its maneuverability in different wind conditions. A waypoint following based strategy for mothership to track its desired trajectory in flight test is developed. The flight test results are also presented to illustrate the effectiveness of the trajectory generation methods. In addition, a nonlinear time-varying feedback control law is developed to regulate the mothership to follow the desired trajectory in the presence of wind. Cable tensions and wind disturbance are taken into account in the design model and Lyapunov based backstepping technique is employed to develop the controller. The mothership tracking error is proved to be capable of exponentially converging to an ultimate bound, which is a function of the upper limit of the unknown component of the wind. The simulation results are presented to validate the controller. Finally, a trajectory-tracking strategy for unmanned aerial vehicles is developed where the autopilot is involved in the feedback controller design. The trajectory-tracking controller is derived based on a generalized design model using Lyapunov based backstepping. The augmentations of the design model and trajectory-tracking controller are conducted to involve the autopilot in the closed-loop system. Lyapunov stability theory is used to guarantee the augmented controller is capable of driving the vehicle to exponentially converge to and follow the desired trajectory with the other states remaining bounded. Numerical and Software-In-the-Loop simulation results are presented to validate the augmented controller. This method presents a framework of implementing the developed trajectory-tracking controllers for unmanned aerial vehicles without any modification to the autopilot.
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Cunis, Torbjørn. "Modeling, analysis, and control for upset recovery : from system theory to unmanned aircraft flight." Thesis, Toulouse, ISAE, 2019. http://www.theses.fr/2019ESAE0027.
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Le travail effectué au cours de cette thèse tente d’apporter des solutions algorithmiques à la problématique de reprise au décrochage d’un aéronef. A travers de nombreux exemples d’application sur des modèles aérodynamiques, le lecteur pourra appréhender les concepts abstraits présentés dans cette thèse. Alors que la capacité pour un aéronef à revenir à une situation nominale après une sortie du domaine de vol est un élément clé pour les systèmes de transport aérien du futur, les recherches menées dans ce cadre sont encore peu nombreuses. Pourtant,un tel dépassement conduit généralement à une perte de contrôle (dénommée LOC-I), que l’Association du Transport Aérien International (IATA) a classé dans la catégorie des « risques les plus élevés pour l’aviation ». Dans un premier temps, nous avons montré que les modèles polynomiaux habituellement utilisés en théorie des systèmes ne représentent pas fidèlement l’aérodynamique d’un modèle d’avion sur l’ensemble de son enveloppe de vol. Nous avons donc tout d’abord montré qu’un modèle polynomial par morceaux représente avec exactitude les coefficients aérodynamiques pour les angles d’attaque faibles et élevés. Nous avons alors pu étendre à cette classe de systèmes, récentes d’étude de bifurcation et d’analyse de stabilité qui utilisent des techniques de programmation semi-définie basées sur la positivité de polynômes (SOS); nous avons notamment appliqué ces résultats au modèle d’avion de transport générique dénommé GTM. Dans le même esprit, nous avons développé un modèle pour un petit aéronef à voilure fixe basé sur des simulations numériques en mécanique des fluides (CFD). Les coefficients dynamiques n’étant pas déterminés en CFD, nous avons identifié le coefficient d’amortissement du tangage en comparant l’analyse de bifurcation et les données de vol, ce qui nous a permis d’étudier à la fois la dynamique et la stabilité du vol en cas de fort décrochage.Des résultats antérieurs ont montré que les techniques SOS étaient prometteuses pour la certification des lois de commande pour des systèmes non-linéaires, cependant sans avoir été appliqués à l’ingénierie aéronautique. En adaptant ces techniques aux modèles polynomiaux par morceaux,nous avons montré qu’il est désormais possible de les utiliser d’une manière précise mais réalisable sur le plan calculatoire. Ensuite, nous avons synthétisé des lois de commandes linéaires et polynomiales pour la récupération d’un fort décrochage. En outre, nous sommes désormais en mesure d’estimer des régions d’attraction pour des modèles polynomiaux par morceaux; pour cela, nous avons proposé un algorithme amélioré pour l’analyse de stabilité locale des systèmes à commutation, tels que ceux qui sont définis par des splines, rendant ainsi notre travail disponible pour l’analyse et la certification futures de modèles d’avion très fidèles.La commande prédictive basée modèle (MPC) s’est avérée être une approche très efficace lorsque la dynamique du système est fortement non linéaire et soumise à des contraintes d’état qui rendent difficile la récupération après le décrochage. Cependant, pour des systèmes réalistes,il est nécessaire de prendre des précautions afin de prouver rigoureusement la stabilité en boucle fermée. En utilisant la technique SOS, nous avons ainsi montré la stabilité d’une stratégie de récupération d’un fort décrochage visant à minimiser la perte d’altitude. Nous avons aussi montré qu’une telle stratégie de commande permet la récupération d’une spirale infernale en utilisant le simulateur GTM.Les résultats de cette thèse sont donc prometteurs et fournissent de nouvelles approches théoriques pour la modélisation, l’analyse de stabilité et le contrôle de la dynamique des futurs aéronefs ainsi que pour le développement et la certification de systèmes de commande de vol visant a prévenir les accidents dus à la perte de contrôleUpset flight dynamics are characterised by unstable, highly nonlinear behaviourof the aircraft aerodynamic system. As upsets often lead to in-flight loss-of-control (LOC-I) accidents,it still poses a severe threat to today’s commercial aviation. Contributing to almost everysecond fatality in civil aviation while representing merely 10% of the total accidents (both fataland nonfatal), the International Air Transport Association has classified LOC-I as the “highestrisk to aviation safety”. Considerable effort has been undertaken in response by academics,manufacturers, commercial airlines, and authorities to predict and prevent LOC-I events as wellas recover from upset conditions into the nominal flight envelope. As result, researchers fromboth aeronautical engineering and system theory have made significant contributions towardsaviation safety; however, approaches from engineering and theory are rather disparate. This thesistherefore focuses on the application and transfer of system theoretical results to engineeringapplications.In particular, we have found simple polynomial models for aircraft dynamics, despite commonin the system theoretical literature, failing to represent full-envelope aerodynamics accurately.Advanced fitting methods such as multi-variate splines, on the other hand, are unsuitable forsome of the proposed functional analysis methods. Instead, a simple piecewise defined polynomialmodel proves to be accurate in fitting the aerodynamic coefficients for low and high angles ofattack. State-of-the-art bifurcation analysis and analysis based on sum-of-squares programmingtechniques are extended for this class of models and applied to a piecewise equations of motionof the Generic Transport Model (GTM). In the same spirit, we develop a model for a small,fixed-wing aircraft based on static continuous fluid dynamics (CFD) simulations. In the lackof dynamic coefficients from CFD, we identify a pitch-damping model comparing bifurcationanalysis and flight data that predicts well dynamics and stability of deep-stall flight.Previous developments in sum-of-squares programming have been promising for the certificationof nonlinear dynamics and flight control laws, yet their application in aeronauticalengineering halted. In combination with piecewise polynomial modeling, we are able to re-applythis technique for analysis in an accurate but computationally feasible manner to verify stablerecovery. Subsequently, we synthesise inherently stable linear and polynomial feedback laws fordeep-stall recovery. We further extend the estimation of regions of attraction for the piecewisepolynomial model towards an improved algorithm for local stability analysis of arbitrary switchingsystems, such as splines, thus making our work available for future analysis and certificationof highly accurate algebraic models.With highly nonlinear dynamics and critical state and input constraints challenging upsetrecovery, model-predictive control (MPC) with receding horizon is a powerful approach. MPCfurther provides a mature stability theory contributing towards the needs for flight control certification.Yet, for realistic control systems careful algebraic or semi-algebraic considerationsare necessary in order to rigorously prove closed-loop stability. Employing sum-of-squares programming,we provide a stability proof for a deep-stall recovery strategy minimising the loss ofaltitude during recovery. We further demonstrate MPC schemes for recovery from spiral andoscillatory spin upsets in an uncertain environment making use of the well-known and freelyavailable high-fidelity GTM desktop simulation.The results of this thesis are thus promising for future system theoretic approaches in modeling,analysis, and control of aircraft upset dynamics for the development and certification offlight control systems in order to prevent in-flight loss-of-control accidents
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Jiang, Xiaomo. "Dynamic fuzzy wavelet neural network for system identification, damage detection and active control of highrise buildings." Connect to this title online, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1110266591.
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Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvii, 221 p.; also includes graphics (some col.). Includes bibliographical references (p. 210-221). Available online via OhioLINK's ETD Center