There are many forms of speed control for an autonomous ground vehicle currently in development. Most use a simple PID controller to achieve a speed specified by a higher-level motion planning algorithm. Simple controllers may not provide a desired acceleration profile for a ground vehicle. Also, without extensive tuning the PID controller may cause excessive speed overshoot and oscillation. This paper examines an approach that was designed to allow a greater degree of control while reducing the computing load on the motion planning software. The SpAM+PI (Speed-based Acceleration Map + Proportional Integral controller) algorithm outlined in this paper uses three inputs: current velocity, desired velocity and desired maximum acceleration, to determine throttle and brake commands that will allow the vehicle to achieve its correct speed. Because this algorithm resides on an external controller it does not add to the computational load of the motion planning computer. Also, with only two inputs that are needed only when there is a change in desired speed or maximum desired acceleration, network traffic between the computers can be greatly reduced. The algorithm uses splines to smoothly plan a speed profile from the vehicle's current speed to its desired speed. It then uses a lookup table to determine the correct pedal position (throttle or brake) using the current vehicle speed and a desired instantaneous acceleration that was determined in the splining step of the algorithm. Once the pedal position is determined a PI controller is used to minimize error in the system. The SpAM+PI approach is a novel approach to the speed control of an autonomous vehicle. This academic experiment is tested using Odin, Team Victor Tango's entry into the 2007 DARPA Urban Challenge which won 3rd place and a $500,000 prize. The evaluation of the algorithm exposed both strengths and weaknesses that guide the next step in the development of a speed control algorithm. / Master of Science

The permanent magnet switched reluctance motor (PMSRM) is hybrid dc motor which has the potential to be more effect than the switched reluctance (SRM) and permanent magnet (PM) motors. The PMSRM has a both a salient rotor and stator with permanent magnets placed directly onto the face of common pole stators. The PMSRM is wound like the SRM and can be controlled by the same family of converters. The addition of permanent magnets creates nonlinearities in both the governing electrical and mechanical equations which differentiate the PMSRM from all other classes of electric motors. The primary goal of this thesis is to develop a cohesive and comprehensive control strategy for the PMSRM so as to demonstrate its operation and highlight its efficiency. The control of the PMSRM starts with understanding its region of operation and the underlying torque production of the motor. The selection of operating region is followed by a both linear and nonlinear electrical modeling of the motor and the design of current controllers for the PMSRM. The electromechanical model of the motor is dynamically simulated with the addition of a closed loop speed controller. The speed controller is extended to add an efficiency searching algorithm which finds the operating condition with the highest efficiency online. / Master of Science

Master of Science / Department of Electrical and Computer Engineering / Dwight D. Day / Micro-hydro turbines generate power for small villages and industries in Afghanistan. They usually produce less than 100 kW of power. Currently the flow into the turbine is controlled manually and the voltage is controlled automatically with an electronic load controller. Excess power not used by the village is dumped into a community water heater. For larger sites that have a reservoir and/or large variable load throughout the day and night, the turbine needs to be fitted with an automatic flow control system to conserve water in the reservoir or deal with the variable loads. Large turbines usually use hydraulic governors that automatically adjust the flow of water into the turbine. For micro-hydro sized plants this method would be too expensive and be difficult to build and maintain locally. For this reason, a 3 phase AC induction motor will be used to move the internal flow control valve of the turbine. Because a sudden change in load is possible (30 – 40%) for micro-hydro plants, the electronic load controller will also be needed to respond to quick changes in load so that the village voltage does not exceed 220V. This report documents the process of building a test system comprising of a dynamic resistive load, microcontroller controlled resistive load, a three phase AC generator and a DC Motor. Where the dynamic resistive load represents the load of the village, the computer controlled resistive load would represent the community water heater, the three phase AC generator represents the Generator on site and the DC Motor together with its DC input voltage would emulate the turbine and its water flow respectively. The DC input voltage would be also controlled with a PWM signal through a delay loop to represent the water gate delay effects on the turbine as close as possible. With this, it would be possible to completely build and test a control system that emulates the dynamics of a water turbine generator.

The thesis is that automation of en-route Air Traffic Management in high complexity airspace can be achieved with a combination of automated tactic planning in a look-ahead time horizon of up to two hours complemented with automated tactic conflict resolution functions. The literature review reveals that no significant results have yet been obtained and that full automation could be approached with a complementary integration of automated tactic resolutions AND planning. The focus shifts to ‘planning for capacity’ and ‘planning for resolution’ and also – but not only – for ‘resolution’. The work encompasses a theoretical part on planning, and several small scale studies of empirical, mathematical or simulated nature. The theoretical part of the thesis on planning under uncertainties attempts to conceive a theoretical model which abstracts specificities of planning in Air Traffic Management into a generic planning model. The resulting abstract model treats entities like the planner, the strategy, the plan and the actions, always considering the impact of uncertainties. The work innovates in specifying many links from the theory to the application in planning of air traffic management, and especially the new fields of tactical capacity management. The second main part of the thesis comprises smaller self-containing works on different aspects of the concept grouped into a section on complexity, another on tactic planning actions, and the last on planners. The produced studies are about empirical measures of conflicts and conflict densities to get a better understanding of the complexity of air traffic; studies on traffic organisation using tactical manoeuvres like speed control, lateral offset and tactical direct using fast time simulation; and studies on airspace design like sector optimisation, dynamic sectorisation and its optimisation using optimisation techniques. In conclusion it is believed that this work will contribute to further automation attempts especially by its innovative focus which is on planning, base on a theory of planning, and its findings already influence newer developments.

Baigiamajame magistro darbe apžvelgiama avaringumo Lietuvos Respublikos valstybinės reikšmės keliuose situacija. Darbe analizuojama automatizuotos važiavimo greičio kontrolės sistemos diegimo Lietuvos automobilių keliuose patirtis, pateikiama automobilių važiavimo greičio tyrimų Lietuvos keliuose analizė. Baigiamajame darbe nagrinėjami visuomenės nuomonės apie automatizuotos važiavimo greičio kontrolės sistemos poveikį eismo saugumui tyrimo rezultatai bei vandalizmo atvejai prieš stacionarius greičio matuoklius. Darbo pabaigoje pateikiamos išvados ir rekomendacijos. Baigiamojo darbo apimtis – 101 psl. teksto be priedų, 30 lentelių, 63 paveikslai ir 3 priedai. / In this Master Thesis an overview of the Republic of Lithuania accident rate situation on national significant roads are given. An analysis of automatic traffic speed control system implementation experience in Lithuanian roads and car speed research on Lithuanian roads are given in this final paper. Also a part of the work reveals research results of public opinion on automatic speed control system influence to traffic safety and cases of vandalism against fixed speed cameras. Conclusions and recommendations are given at the end of the paper. Master thesis consists of 101 pages pure text without appendixes, 30 tables, 63 pictures ant 3 appendixes.

System characteristics of automated pumping systems may change due to wear, aging of piping, and accumulation of deposits in the system and/or due to configuration changes. Such changes might result in conflicts between the controlling algorithms and the actual system requirements for each particular case. The said mismatch between the actual physical system and the software controlling it, may result in inefficient operation of the pump which may even lead to total system failures (overpressurization of instrumentation and sensing elements etc.) due to temporary malfunctioning of the system components or permanent damages incurred by them during operating under unsuitable conditions. It is intended in this study to design and construct an experimental automated pump bench with operational components (mechanical, electronical and instrumentation etc.), serving in a system introducing multiple geometric heads and its controlling and monitoring software in order to visualize effects of the above-mentioned cases for education and training purposes. System characteristics data acquisition module (system test module) provides the means of recognizing new pump and system characteristics, provided that they were changed due to some reason (throttled valve, changed pump speed, changed flowrate or elevation of discharge etc.). Then the pump operation module enables users to make comparative judgments by observing the effects of the abovementioned changes. Above-mentioned testing sequence and monitoring of changing physical quantities were achieved by employing four pressure transducers, a custom made DC motor operated -throttling valve with position feedback which was designed and constructed specifically for this study and a variable frequency drive (VFD) which were all connected to a custom made Main Control Circuit (MCC) Board.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This doctoral thesis presents the development of sensorless methods aiming the rotor speed control of asymmetrical two-phase induction motors. Initially, the machine mathematical model is presented. From the machine model, two methods for identification of electrical parameters of the induction machine are presented. The first method is based on the classical tests for electrical parameter estimation on three-phase induction motors, while the second method uses a RLS algorithm for the electrical parameters identification. Moreover, a vector control scheme applied to asymmetrical induction machines is presented. The influence that the machine asymmetry impacts on the field indirect vector control rotating at synchronous speed is analyzed. Simulation results show the coupling and the oscillations on the stator currents. The rotor speed estimation is carried out firstly by a MRAS estimator applied to single-phase induction motor drive. Furthermore, three rotor speed estimation methods based on continuous and discrete time sliding mode observers are proposed. The proofs of stability and convergence of these algorithms are developed and presented. The limits for the switching gains of the sliding mode observer are presented for continuous and discrete time. These limits are distinct and are highlighted in this study. Besides, a geometric modulation technique for three-leg voltage source inverters driving two-phase machines is presented. The rotor speed control is carried out from two schemes. The first method uses a discrete-time PI controller, while the second scheme uses a RMRAC controller. Simulation and experimental results are presented to validate the proposed techniques. / Esta tese faz o desenvolvimento de técnicas sensorless para o controle de velocidade rotórica de motores de indução bifásicos assimétricos. Inicialmente, o modelo matemático deste motor é apresentado. A partir da obtenção deste modelo, dois métodos para realização de ensaios com o intuito de determinar os parâmetros elétricos da máquina são desenvolvidos. O primeiro método é baseado nos ensaios clássicos para estimação de parâmetros de máquinas de indução trifásicas, enquanto o segundo método faz o uso de um algoritmo RLS identificação dos parâmetros elétricos. Além disso, neste trabalho um método de controle vetorial aplicado a máquinas de indução assimétricas é desenvolvido. É demonstrada a influência que a assimetria da máquina resulta no uso do controle vetorial orientado indiretamente no campo em eixos síncronos. Resultados de simulações mostram o acoplamento e consequentes oscilações nas correntes estatóricas. A estimação da velocidade rotórica é realizada inicialmente a partir do desenvolvimento de um estimador MRAS aplicado a um motor de indução monofásico. São propostos três métodos de estimação da velocidade rotórica a partir de algoritmos por modos deslizantes em tempo contínuo, e três métodos desenvolvidos em tempo discreto. As provas de estabilidade e convergência destes algoritmos são desenvolvidas e apresentadas. Ficam evidentes as diferenças entre os métodos em tempo contínuo e tempo discreto, bem como os limites para os ganhos dos observadores. Ainda, uma técnica de modulação para conversores de três braços acionando carga bifásicas é apresentada. O controle da malha de velocidade rotórica é realizado a partir de dois esquemas, o primeiro usa um controlador PI, enquanto o segundo método faz o uso de um controlador RMRAC. Resultados de simulação e experimentais são apresentados para validação das técnicas propostas.

Made available in DSpace on 2014-12-17T14:56:13Z (GMT). No. of bitstreams: 1 FlavioGD_DISSERT.pdf: 434327 bytes, checksum: 80a9ab9e6651a6af8ae71caa0fd3bfec (MD5) Previous issue date: 2011-09-09 / This paper describes the study, computer simulation and feasibility of implementation of vector control speed of an induction motor using for this purpose the Extended Kalman Filter as an estimator of rotor flux. The motivation for such work is the use of a control system that requires no sensors on the machine shaft, thus providing a considerable cost reduction of drives and their maintenance, increased reliability, robustness and noise immunity as compared to control systems with conventional sensors / Esta disserta??o apresenta o desenvolvimento de uma simula??o computacional com a finalidade de demonstrar o funcionamento do controle vetorial para velocidade de um motor de indu??o trif?sico utilizando m?todo de estima??o pelo Filtro de Kalman Estendido, bem como os procedimentos necess?rios para sua implementa??o pr?tica. A motiva??o maior que influenciou a pesquisa est? na utiliza??o de um sistema de controle inovador que n?o necessita de sensores no eixo da m?quina (t?cnica sensorless), proporcionando desta forma uma consider?vel redu??o nos custos de acionamentos e manuten??o, aumento da confiabilidade, da robustez e da imunidade a ru?dos em rela??o ao controle de motores convencionais com sensores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis presents a sensorless speed control drive of Brushless DC motors used in reciprocating compressors. These compressors cause periodic load torque variations on the motor, consequently mechanical vibrations and acoustic noise are presented as well. As a result, a discrete speed controller based on the internal model principle is proposed. This controller aims to track the speed reference and to reduce the periodic torque disturbances caused by the compressor. The proposed controller consists of a rotor position and speed estimator, and a discrete speed controller with variable sampling frequency that depend on the rotor speed. The discrete estimator is based on the zero crossing point detection of the back-electromotive force. This method is optimized by using a Least Squares algorithm. The speed controller consists of two control actions, repetitive and proportional-derivative actions. In order to complement the drive system operation, a new procedure to start a BLDCM with current control is proposed. This technique ensures the maximization of the electromagnetic torque during startup and to avoid demagnetization of the permanent magnet by the stator current. Finally, simulation and experimental results are presented to demonstrate the performance of the techniques adopted, as well as the main advantages, disadvantages and operational limitations of the experimental implementation. In addition, the performance of the load torque rejection is evaluated by comparing the harmonic spectrum of the torques produced by the proposed speed controller and a PI controller. / Esta dissertação apresenta um sistema de acionamento e controle de velocidade sensorless para motores Brushless DC utilizados em compressores alternativos. Estes compressores provocam variações periódicas de carga sobre o motor causando vibrações mecânicas e ruído acústico. Em vista disso, um controlador discreto de velocidade baseado no princípio do modelo interno é proposto. Este controlador visa o rastreamento assintótico de uma velocidade de referência e a redução dos distúrbios cíclicos de conjugado provocados pelo compressor. Para isso, o sistema proposto é constituído por um estimador discreto da posição e da velocidade do rotor, e um controlador discreto de velocidade com frequência de amostragem variável em função da velocidade de rotação. O estimador discreto baseia-se na deteção do cruzamento da força contra-eletromotriz por zero, a qual é otimizada por meio de um algoritmo de Mínimos Quadrados. O controlador de velocidade é composto por duas ações de controle, uma ação repetitiva e uma proporcionalderivativa. De forma a complementar a operação do sistema de acionamento, um novo procedimento de partida com controle de corrente é proposto para o BLDCM. Este procedimento possibilita a maximização do conjugado eletromagnético do motor durante a partida e ainda evita a desmagnetização dos ímãs pela incidência de altas correntes estatóricas. Por fim, resultados de simulação e experimentais são apresentados para demonstrar o desempenho das técnicas adotadas, assim como as principais vantagens, desvantagens e limitações operacionais da implementação experimental. Além disso, a performance da rejeição parcial do conjugado de carga é avaliada com a comparação do espectro harmônico dos conjugados produzidos pelo controlador de velocidade proposto e por um controlador proporcional-integral.

Diploma thesis describes design and realization of hardware and software for controlling and regulation of the high-speed drive with BLDC motor, which will serve as a spindle for CNC milling machine. The thesis described in detail the schematic design and the design of printed circuit board of the power part, control part and power supply part of the three-phase transistor inverter controlled by DSP processor. It is also described in detail program of DSP processor for controlling and regulation of the BLDC motors, which the function is verified by the final measurements. The result of Diploma thesis is functional high-speed drive with BLDC motor.