Methods for estimating vehicle-terrain interaction parameters for small scale robotic vehicles have been formulated and evaluated using both simulation and experimental studies. A model basis was developed, guided by experimental studies with an iRobot PackBot. The intention was to demonstrate whether a nominally instrumented robotic vehicle could be used as a test platform for generating data for vehicle-terrain parameter estimation. A comprehensive skid-steered model was found to be sensitive enough to distinguish between various forms of unknown terrains. This simulation study also verified that the Bekker model for large scale vehicles adopted for this research was applicable to the small scale robotic vehicle used in this work. This fact was also confirmed by estimating coefficients of friction and establishing their dependence on forward velocity and turning radius as the vehicle traverses different terrains. On establishing that mobility measurements for this robotic were sufficiently sensitive, it was found that estimates could be made of key dynamic variables and vehicle-terrain interaction parameters. Four main contributions are described for reliably and robustly using PackBot data for vehicle-terrain property estimation. These estimation methods should contribute to efforts in improving mobility of small scale tracked vehicles on uncertain terrains. The approach is embodied in a multi-tiered algorithm based on the dynamic and kinematic models for skid-steering as well as tractive force models parameterized by key vehicle-terrain parameters. In order to estimate and characterize the key parameters, nonlinear estimation techniques such as the Extended Kalman Filter (EKF), Unscented Kalman Filter (UKF), and a General Newton Raphson (GNR) method are integrated into this multi-tiered algorithm. A unique idea in using an EKF with an added State Noise Compensation algorithm is presented which shows its robustness and consistency in estimating slip variables and other parameters for deformable terrains. In the multi-tiered algorithm, a kinematic model of the robotic vehicle is used to estimate slip variables and turning radius. These estimated variables are stored in a truth table and used in a skid-steered dynamic model to estimate the coefficients of friction. The total estimated slip on the left and right track, along with the total tractive force computed using a motor model, are then used in the GNR algorithm to estimate the key vehicle-terrain parameters. These estimated parameters are cross-checked and confirmed with EKF estimation results. Further, these simulation results verify that the tracked vehicle tractive force is not dependent on cohesion for frictional soils. This sequential algorithm is shown to be effective in estimating vehicle-terrain interaction properties with relatively good accuracy. The estimated results obtained from UKF and EKF are verified and compared with available experimental data, and tested on a PackBot traversing specified terrains at the Southwest Research Institute (SwRI), Small Robotics Testbed in San Antonio, Texas. In the end, based on the development and evaluation of small scale vehicle testing, the effectiveness of on-board sensing methods and estimation techniques are also discussed for potential use in real time estimation of vehicle-terrain parameters. / text

Power losses in the grid are important, and as the power losses decrease the efficiency increases. Not much research has been done recently on the Newton-Raphson Power Flow (NRPF) method in polar form for systems with High Voltage Direct Current (HVDC) subsystems. The point of departure for this thesis is based on decoupling the NR Power Flow method Power flow problems are solved for many fundamental problems in the operation and planning of the power system. Although many methods are available to solve these problems, this thesis focuses on developing an enhanced HVDC power flow method with improved computational efficiency and convergence stability. A comparison of the results with full Newton-Raphson Power Flow method is presented to evaluate the performance of the proposed method. Simulations were conducted on the 14-bus and 30-bus IEEE systems. Two and three converters are shown to improve the voltage magnitude, active and reactive power profile .The overall results indicate which mode is the best mode compared to others depending on the bus importance.

This thesis presents a novel approach for a power system to find a practical power flow solution when all the generators in the system have hit their real power output limits, such as some generator units shutting down or load outages. The approach assumes the frequency of the system is unable to be kept at the rated value (usually 60 or 50 Hz) and accordingly, the generator real power outputs are affected by the system frequency deviation. The modification aims to include the system frequency deviation as a new state variable in the power flow so that the power system can be described in a more precise way when the generation limits are hit and the whole system is not operated under the normal condition. A new mathematical formulation for power flow is given by modified the conventional power flow mismatch equation and Jacobian matrix. The Newton – Raphson method is particularly chose to be modified because Newton – Raphson method is most widely used and it is a fast convergent and accurate method. The Jacobian matrix will be augmented by adding a column and a row. Matlab is used as a programming tool to implement the Power Flow for Long Term Frequency Stability (PFLTFS) method for a simple 4-bus system and the IEEE 118-bus system. And PSS/E Dynamic simulation is used to verify the steady state solution from PFLTFS is reasonable. The PSS/E Dynamic Simulation plots are used to analyze the long term frequency response. The PFLTFS method provides a technique for solving an abnormal state system power flow. From the results we can conclude that the PFLTFS method is reasonable for solving power flow of a real power unbalanced system.

Thesis (M.S. )--Duquesne University, 2007. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p. 59-61) and index.

Made available in DSpace on 2014-06-11T19:30:51Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-06-06Bitstream added on 2014-06-13T21:01:24Z : No. of bitstreams: 1 carvalho_cg_dr_ilha.pdf: 1638470 bytes, checksum: ca46c8123050c9866b9ab13bc540b94d (MD5) / Este trabalho apresenta um modelo analítico para uma linha de transmissão trifásica com plano de simetria vertical. Devido às características físicas dessa linha, é possível representá-la por um sistema constituído por uma linha monofásica e por uma linha bifásica. Nesse sistema, as equações que descrevem o comportamento das grandezas nos terminais da linha monofásica são conhecidas, enquanto que as equações da linha bifásica foram obtidas utilizando uma matriz de transformação escrita explicitamente em função dos parâmetros da linha trifásica. Em seguida, as grandezas modais da linha trifásica foram convertidas para o domínio das fases e as equações resultantes representam um modelo analítico desenvolvido diretamente no domínio das fases dessa linha. Para verificar o desempenho do modelo, foram realizadas simulações considerando a energização e a incidência de uma descarga atmosférica em uma linha trifásica de 440 kV. Esses resultados foram comparados aos resultados obtidos com a linha representada por meio de um método clássico (representação nos modos) e as simulações mostraram que o modelo responde adequadamente na faixa de frequência correspondente aos procedimentos de manobra e chaveamento. O modelo desenvolvido leva em conta o efeito da frequência sobre os parâmetros longitudinais da linha e também o fato de que os parâmetros da linha são distribuídos ao longo de seu comprimento. Acredita-se que a análise das matrizes, que dão suporte ao modelo, e a validação do modelo no domínio do tempo possa dar origem, futuramente, a um modelo de linha de transmissão desenvolvido diretamente no domínio do tempo. Tal modelo, pelo fato de ser obtido diretamente das equações de propagação da linha, permitirá a obtenção de resultados de simulações, de transitórios eletromagnéticos que ocorrem... / This paper presents an analytical model to a three-phase transmission line with vertical symmetry plane. Because of physical characteristics of this line, it is possible to represent it by a system consisting of a single-phase and a two-phase line. In this system, the equations that describe the behavior of single-phase terminals quantities are known, while the two-phase equations were obtained using a transformation matrix written explicitly in terms of the parameters of three-phase line. Then, the modal quantities of three-phase line were converted into phase domain and the resulting equations represent an analytical model developed directly in phase domain of this line. To verify the performance of the model, were performed simulations considering the energization and impact of a lighting surge in a 440 kV three-phase line. These results were compared to results obtained with the line represented by a classical method (presentation modes) and simulations show that the model responds appropriately in the frequency range corresponding to the operation and switching procedures. The model developed takes into account the frequency effect on the longitudinal line parameters and also the fact that the line parameters are distributed along their length. It is believed that the matrix analysis, that support the model and the model validation in time domain may give rise in the future to a transmission line model developed directly in time domain. Such a model, because it is obtained directly from the propagation equations of line, will enable the more accurate results of simulations of electromagnetic transients that... (Complete abstract click electronic access below)

Orientador: Suzinei Aparecida Siqueira Marconato / Banca: Maria Aparecida Bená / Banca: Jamil Viana Pereira / Resumo: As funções estudadas no Ensino Médio se resumem às polinomiais de primeiro e segundo grau, modulares, exponenciais, logarítmicas e trigonométricas. Os problemas de encontrar zeros de função são recorrentes e auxiliam na construção de gráficos e em suas análises. Dessa forma, o presente trabalho tem o objetivo de apresentar três métodos numéricos (métodos da bissecção, de Newton-Raphson e das secantes) para encontrar os zeros de função. Em especial, o método de Newton-Raphson é um exemplo de equação discreta, cujo ponto fixo será o zero da função. A teoria das Equações Discretas será abordada no Capítulo 3. No Capítulo 4, discutiremos o método gráfico que introduz os métodos numéricos. Na sequência, nos Capítulos 5, 6 e 7, é que, de fato, abordaremos os três métodos numéricos. Por fim, apresentamos uma proposta de atividade para o Ensino Médio. Para além de encontrar os zeros de função, os métodos numéricos motivam o estudo inicial de recorrência, limites e derivadas. Além disso, as aplicações dos métodos em sala de aula podem ser realizadas com o auxílio de softwares matemáticos que trabalhem com planilhas e gráficos / Abstract: The functions studied in high school are summarized in polynomials of first and second degree, modular, exponential, logarithmic and trigonometric. The problems to find zeros of functions are recurrent and assist in constructing the graphs and their analysis. Thus, this dissertation aims to present three numerical methods (methods of bisection, Newton-Raphson and secant) to find the zeros of function. In particular, the Newton-Raphson method is an example of a discrete equation which the fixed point will be the zero of function. The theory of discrete equations will be discussed in Chapter 3. Chapter 4 outlines the graphical method which introduces the numerical methods. Following, in Chapter 5, 6 and 7, is that, in fact, we'll discuss the three numerical methods. Finally, we present a proposed activity for high school. In addition to finding the zeros of function, the numerical methods motivate the initial study of recurrence, limits and derivatives. Furthermore, the applications of methods in the classroom can be performed with the aid of mathematical software to work with spreadsheets and charts / Mestre

Made available in DSpace on 2015-06-17T19:34:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-09-29. Added 1 bitstream(s) on 2015-06-18T12:49:14Z : No. of bitstreams: 1 000832285.pdf: 454402 bytes, checksum: 49609651ea8a2fa968ca19324e011ebc (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / As funções estudadas no Ensino Médio se resumem às polinomiais de primeiro e segundo grau, modulares, exponenciais, logarítmicas e trigonométricas. Os problemas de encontrar zeros de função são recorrentes e auxiliam na construção de gráficos e em suas análises. Dessa forma, o presente trabalho tem o objetivo de apresentar três métodos numéricos (métodos da bissecção, de Newton-Raphson e das secantes) para encontrar os zeros de função. Em especial, o método de Newton-Raphson é um exemplo de equação discreta, cujo ponto fixo será o zero da função. A teoria das Equações Discretas será abordada no Capítulo 3. No Capítulo 4, discutiremos o método gráfico que introduz os métodos numéricos. Na sequência, nos Capítulos 5, 6 e 7, é que, de fato, abordaremos os três métodos numéricos. Por fim, apresentamos uma proposta de atividade para o Ensino Médio. Para além de encontrar os zeros de função, os métodos numéricos motivam o estudo inicial de recorrência, limites e derivadas. Além disso, as aplicações dos métodos em sala de aula podem ser realizadas com o auxílio de softwares matemáticos que trabalhem com planilhas e gráficos / The functions studied in high school are summarized in polynomials of first and second degree, modular, exponential, logarithmic and trigonometric. The problems to find zeros of functions are recurrent and assist in constructing the graphs and their analysis. Thus, this dissertation aims to present three numerical methods (methods of bisection, Newton-Raphson and secant) to find the zeros of function. In particular, the Newton-Raphson method is an example of a discrete equation which the fixed point will be the zero of function. The theory of discrete equations will be discussed in Chapter 3. Chapter 4 outlines the graphical method which introduces the numerical methods. Following, in Chapter 5, 6 and 7, is that, in fact, we'll discuss the three numerical methods. Finally, we present a proposed activity for high school. In addition to finding the zeros of function, the numerical methods motivate the initial study of recurrence, limits and derivatives. Furthermore, the applications of methods in the classroom can be performed with the aid of mathematical software to work with spreadsheets and charts

Orientadores: Secundino Soares Filho, Anesio dos Santos Jr / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-07-27T03:45:06Z (GMT). No. of bitstreams: 1 Lima_FlavioGuilhermedeMelo_D.pdf: 4842117 bytes, checksum: c30c5445d55e6b97e6857d86e7a136ff (MD5) Previous issue date: 2000 / Resumo: Este trabalho apresenta um método paramétrico de resolução do problema de Fluxo de Potência Ótimo (FPO) para sistemas de potência de grande porte. O trabalho é uma continuação das pesquisas anteriores em otimização paramétrica aplicada no FPO desenvolvidas na UNICAMP e na Universidade McGiII, em Montreal, Canadá. A abordagem paramétrica consiste em relaxar o problema original (FPO) através da incorporação de termos paramétricos na função objetivo e nas restrições de igualdade e desigualdade dando surgimento ao problema relaxado (Fluxo de Potência Ótimo Paramétrico­FPOP). A relaxação do FPO assegura que qualquer solução inicial arbitrária, factível ou não no problema original, seja solução ótima do FPO relaxado. Através da variação de um parâmetro, uma família de problemas paramétricos é resolvida pelo método de Newton-Raphson, cujas soluções formam um caminho que parte do problema relaxado indo até a solução do problema original. Uma estratégia eficiente para a determinação do conjunto de restrições de desigualdade ativas de cada problema paramétrico foi desenvolvida. O método foi testado em duas versões do sistema elétrico brasileiro Sul-Sudeste, uma contendo 810 barras e uma outra com 2256 barras na qual está representada a interligação do Sul-Sudeste com o Norte-Nordeste. Foram considerados os problemas de minimização do custo de geração, minimização de perdas ativas e minimização de desvio de tensão. Os resultados mostraram que a abordagem paramétrica é uma técnica robusta e eficiente de resolução de problemas de FPO em sistemas de grande porte / Abstract: The aim of this work is to present a parametric method for the resolution of the Optimal Power Flow (OPF) problem applied to large scale power systems. This research work on parametric optimization applied to OPF was developed at UNICAMP and at McGiII University, in Montreal, Canada. The parametric approach consists of relaxing the original problem (OPF) by incorporating parametric terms to the objective function and to the equality and inequality constraints leading to a relaxed problem (Parametric Optimal Power Flow ­POPF). The relaxation of the OPF assures that any arbitrary initial solution be the optimal solution of the relaxed OPF, even if this initial solution is feasible or not for the original problem. After a parameter change, a family of parametric problems is resolved by the Newton-Raphson method, whose solutions form a path from the relaxed problem up to the solution of the original problem. An efficient strategy was studied for the determination of the set of active inequality constraints for each parametric problem. The method was tested for two versions of the Brazilian South-Southeast power system, one containing 810 buses and another 2256 buses in which the South-Southeast to North-Northeast interconnection is represented. Problems concerned with minimization of generation costs, active losses and voltage profile were considered. The results showed that the parametric approach is a robust and efficient technique for the resolution of OPF problems for large scale power systems / Doutorado / Doutor em Engenharia Elétrica

The steadily increasing demand of wood forces sawmills to increase the efficiency and effectiveness of their equipments. The weak parts and the twist in wooden logs have been documented as the most common and crucial defect in sawn lumber. In this thesis we are going to implement a program which is able to determine the weak parts in wooden logs. The implementation will be in two languages C++ and Matlab. Parts of the program are going to be implemented sometimes by C++ and sometimes by Matlab therefore different designs are going to be tested. The aim of this thesis is to check whether these designs will meet the real time bound of 10 m/s. The result shows that there is a huge difference in time performance for the different designs. Therefore, different discretization levels were used in order to meet the deadline of 10m/s. We found that in order to get better speed one should calculate the matrix for the function F and the Jacobian function J by using C++ not by Matlab. Also we found that when we called functions from one language to another an extra time is added.

This thesis treats how to generate collision information for multibody simulations in AgX Dynamicswhere the geometries are described with the data structure boundary representation, BREP. BREP is adata structure that contains the exact mathematical description of each individual surface. To describecomplex surfaces exact and efficient non uniform rational basis spline, NURBS, is used and for trivialsurfaces like planes or spheres simpler equations is used. Since all surfaces in a BREP is described veryaccurate, the accuracy for the collision information can be set high without affecting the amount of dataneeded to describe the geometries.To make AgX Dynamics able to calculate forces in a multibody simulation, collision informationabout were and how much two geometries are intersecting is required. The collision information containswere the overlap between two geometries is, how much the objects have penetrated each other and thedirection for which the objects have to separate. To find the penetration depth and the overlap theNewton Raphson method were used. The experiments conducted, showed that it is possible to useBREPs as a description of geometries to produce the collision information needed for the physics engineused by AgX Dynamics to handle collisions. A comparison between trimesh and BREP for producingthe collision information, shows that data usage is much lower for the representation of geometries withBREPs than trimesh. The results also shows that the accuracy can be significantly higher than fortrimesh as the data usage for trimesh becomes non practical to handle when the required accuracy ishigh. With the high accuracy and with the smooth surfaces used with the BREP the artificial friction isalmost negligible except for cases were intersection points could not be found all around the intersectioncurves due to limitations in the algorithm. / Detta examensarbete behandlar hur man skapar kollisionsinformation för flerkropps simuleringar i AgXDynamics där geometrier beskrivs med datastrukturen boundary representation, BREP. BREP är endatastruktur som innehåller den exakta matematiska beskrivningen för varje enskild yta. Att beskrivakomplexa ytor exakta och effektivt med non uniform rationell basis spline, NURBS, används och förtriviala ytor som plan eller sfärer kan enklare ekvationer används. Eftersom alla ytor i en BREP beskrivsexakt, kan noggrannheten för kollisions informationen sättas högt utan att påverka den mängd data sombehövs för att beskriva geometrier.För att göra AgX Dynamics kunna beräkna krafter i en flerkroppssimulering, krävs kollisions informationom var och hur mycket två geometrier kolliderar. Kollisions informationen innehåller varöverlappningen mellan två geometrier är, hur mycket objekten har penetrerat varandra och den riktningsom föremålen ska separeras. För att hitta penetrationsdjup och överlapp användes Newton Raphsonsmetod. De experiment som utförts, visade att det är möjligt att använda BREPs som en beskrivning avgeometrier för att producera kollisions information som behövs för att den fysikmotor som används avAGX Dynamics ska kunna hantera kollisioner. En jämförelse mellan trimesh och BREP för att producerakollisionen informationen, visar att dataanvändning är mycket lägre när geometrier representeras medBREPs än trimesh. Resultaten visar också att noggrannheten kan vara väsentligt högre för BREP änför trimesh eftersom dataanvändning för trimesh blir opraktiskt att hantera när noggrannheten är hög.Med hög noggrannhet och med de släta ytor som används med BREP blev den artificiella friction nästanförsumbar, utom i fallen där skärningspunkter inte kunde hittas runt hela skärningskurvor på grund avbegränsningar i algoritmen.