Utilização de experimentos com relés para identificação de pontos da resposta em freqüência de sistemas multivariáveis quadrados e sintonia de controladores PID descentralizados. / It use relay experiments for square multivariable system frequency response and decentralized PID controller tunning.

Thesis submitted in compliance with the requirements for the Master's Degree in Technology: Electrical Engineering - Light Current, Durban University of Technology, Department of Electronic Engineering, 2008. / Linear control systems can be easily tuned using classical tuning techniques such as the Ziegler-Nichols and Cohen-Coon tuning formulae. Empirical studies have found that these conventional tuning methods result in an unsatisfactory control performance when they are used for processes experiencing the negative destabilizing effects of strong nonlinearities. It is for this reason that control practitioners often prefer to tune most nonlinear systems using trial and error tuning, or intuitive tuning. A need therefore exists for the development of a suitable tuning technique that is applicable for a wide range of control loops that do not respond satisfactorily to conventional tuning. Emerging technologies such as Swarm Intelligence (SI) have been utilized to solve many non-linear engineering problems. Particle Swarm Optimization (PSO), developed by Eberhart and Kennedy (1995), is a sub-field of SI and was inspired by swarming patterns occurring in nature such as flocking birds. It was observed that each individual exchanges previous experience, hence knowledge of the “best position” attained by an individual becomes globally known. In the study, the problem of identifying the PID controller parameters is considered as an optimization problem. An attempt has been made to determine the PID parameters employing the PSO technique. A wide range of typical process models commonly encountered in industry is used to assess the efficacy of the PSO methodology. Comparisons are made between the PSO technique and other conventional methods using simulations and real-time control. / National Research Foundation

published_or_final_version / Mechanical Engineering / Master / Master of Philosophy

This thesis proposes and implements a flexible platform to perform Hardware-In-the-Loop (HIL) co-simulation using a Field-Programmable-Gate-Array (FPGA). The HIL simulations are performed with SystemModeler working as a software simulator and the FPGA as the co-simulator platform for the digital hardware design. The work presented in this thesis consists of the creation of: A communication library in the host computer, a system in the FPGA that allows implementation of different digital designs with varying architectures, and an interface between the host computer and the FPGA to transmit the data. The efficiency of the proposed system is studied with the implementation of two common digital hardware designs, a PID controller and a filter. The results of the HIL simulations of those two hardware designs are used to verify the platform and measure the timing and area performance of the proposed HIL platform.

O presente trabalho trata da implementação de um sistema de controle PID auto-ajustável. O trabalho desenvolvido compreende as seguintes etapas: ajuste dos parâmetros da planta, ajuste do controlador sem ajuste dos parâmetros da planta e ajuste do controlador com projeção dos parâmetros do controlador. O algoritmo de ajuste do controlador é baseado no critério de variância mínima generalizada e o de ajuste de parâmetros da planta é baseado no método dos mínimos quadrados estendido. Os parâmetros do controlador são projetados na região factível de existência física dos parâmetros do controlador contínuo através de uma técnica de programação quadrática. Os algoritmos foram implementados e testados em laboratório no controle de posição ou velocidade de um servomotor cc. Utilizou- se um computador pessoal AT-286, 25 MHz, para executar os algoritmos, um sistema de potência com um modulador de largura de pulso digital associado a um recortador de onda e um encoder óptico para realimentação de velocidade. / The present work deals with the implementation of a self- tunning PID control. The work developed cornprises the tunning of the plant parameters, the tunning of the controller without tunning the plant parameters and the tunning of the controller with projection of the controller parameters. The controller algorithrn is based on the generalised minimum-variance criterion and the tunning of the plant parameters is based on the extended recursive least square method. The parameters of the controller are projected onto the region of physical existence of the continuous controller parameters by a quadratic programming technique. This guarantees a PID behavior for the digital controller. The algorithms were implemented and tested in laboratory for position and velocity control of a servomotor dc. We used a personal computar AT- 286, 25 MHz, to run the algorithms, a power eletronic driver with a digital pulse width modulate associate with a chopper and an optic encoder for velocity feedback.

El presente asunto de estudio contempla el diseño de un sistema integrado para el pasteurizado de la leche materna en el Banco de Leche Humana del Instituto Nacional Materno Perinatal. Actualmente, el procesamiento de la leche materna se realiza con la ayuda de tres equipos que funcionan de manera secuencial. El proceso que se sigue es conocido como pasteurización tipo Holder, el cual se caracteriza por someter a la leche materna a una temperatura de 62.5°C durante 30 minutos para después enfriarla rápidamente en menos de 15 minutos generando un cambio brusco en la temperatura que anula la acción de microorganismos que podrían dañar la salud de los neonatos. El desarrollo de esta tesis propone un sistema de control mediante modelamiento matemático y simulación en computadora. Para el diseño del sistema de pasteurizado, se realiza previamente un modelamiento matemático de los actuadores en conjunto con la planta. Para la etapa de precalentamiento y pasteurización se modela la resistencia eléctrica de inmersión en conjunto con el tanque que almacena los frascos de leche materna empleando ecuaciones diferenciales a partir de las leyes físicas del proceso, mientras que para la etapa de enfriamiento rápido se modela la celda peltier empleando equivalencias eléctricas a fenómenos térmicos que suceden en este dispositivo. Posteriormente, se diseña el controlador para cada etapa utilizando el método del lugar geométrico de raíces. Se plantean los requerimientos que debe cumplir el controlador a diseñar, lo cual lleva a elegir un controlador PI que es evaluado para tres valores del factor de amortiguamiento. Con el valor adecuado se hacen las simulaciones y se identifican los nuevos tiempos para cada etapa del proceso. Como resultado se obtiene un proceso optimizado del pasteurizado de leche materna junto con una alternativa de refrigeración eficiente y una propuesta física de pasteurización diferente a la utilizada en el Banco de Leche Humana del Instituto Nacional Materno Perinatal. / Tesis

Orientador: Laércio Ender. / Co-orientador: Henry França Méier. / Co-orientador: Vinicyus Rodolfo Wiggers. / Dissertação (mestrado) - Universidade Regional Blumenau, Centro de Ciências Tecnológicas, Programa de Pós-Graduação em Engenharia Química.

In this thesis, a digital-PID-control single-inductor triple-output (SITO) DC-DC converter is realized in AMS 0.35mum CMOS technology. The size of the chip is about 1600 mum x 1700 mum. To improve load current and reduce cross regulation, a Pre-Sub-Period inductor-current regulation is proposed. Based on the maximum duty cycle limiter, an adaptive inductor current adjustment is realized when the duty cycle of the digital PWM signal is larger than the set maximum duty cycle. By an optimized phase control sequence, the S&H stages of the feedback switching and ADC are controlled to on/off with a minimized delay time. Moreover, the control sequence can virtually remove the setting time. / Multiple voltage supplies are necessary to satisfy the different voltage supply requirements of the different on-chip blocks to reduce power consumption in modem electronic devices, such as the modem embedded systems, the portable devices, personal computing devices and wireless communications and imaging systems. For example, WiMAX transmitter includes different sub-blocks: Baseband processor, IQ modulator and power amplifier. Different blocks should operate with the different power supply voltages to satisfy the different requirements. / Single-input multiple-output DC-DC converter is presented to provide the different voltage supplies and reduce the cost on the elements such as the inductor on PCB and save PCB area. Meanwhile, to remove cross regulation and improve load driving capability, the DC-DC converter should operate in the pseudo-continuous mode/discontinuous mode (P-CCM/DCM). However, in the previous designs, the DC current in the inductor is fixed. When the load becomes heavy enough, cross regulation will significantly affect across the different sub-converters. / Jia, Jingbin. / "December 2009." / Adviser: KaNang Leung Alex. / Source: Dissertation Abstracts International, Volume: 72-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 121-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

The study on animal models to investigate different human diseases has made a remarkable contribution to the field of biomedical science. Many studies demonstrating the behavior activities of Drosophila have been studied with a motion tracking system. Most of these studies have been performed by the conventional paradigm where the Drosophila is held fixed by tethering or within the limited space. In this paper, we demonstrate the Active Omnidirectional Treadmill System (AOT) which enables the physically unrestricted Drosophila to navigate infinitely in two-dimensional space with the privilege of real-time tracking. The system maintains the position of the fly at a specific position by compensating the motion of the fly by counter direction motion of the sphere. The system is capable of maintaining the position error < 1000 µm for 89.7% of the time and the angular error < 5o 80.0% of the time. The study evaluates the performance of the different feedback control system through the experimental and simulation results. The successful phototaxis experiment was conducted to validate the usability of the system. The integration of the treadmill system with other peripherals for olfactory, vision and thermal stimuli can be a powerful tool to study the longitudinal behavior of the Drosophila. Further, the integration of the system with the optical microscopic device can be used to perform the brain imaging of the walking Drosophila.

Chemical Mechanical Polishing, (CMP), pads made of polyurethane material are utilized in the Integrated Circuit, (IC), industry to planarize wafers between successive process steps. The properties of such pads and their behavior must be known in order to determine under what conditions and for how long they can be used efficiently. This research involved the development of a system to study the properties of such pads. The system developed during this research enabled the pads to be tested under varying physical conditions. The setup used a combination of several instruments to provide excitation to the pad and acquire a measure its response. A central computer controlled the instrumentation system employed. In this research the determination of the physical properties of CMP pads was accomplished through the use of Ultra Sound testing. Ultra sound methods offer a non-destructive method of characterizing pads to be used in the production of IC wafers. Ultra sound characterization is currently one of the most widely used techniques utilized for non-destructive inspection. This report provides a detailed account of the hardware instruments involved and the method of integration of those instruments into a system that could easily, rapidly and accurately characterize CMP pads. The pad response was measured in terms of the signal voltage transmitted through the pad to the ultrasound sensor. The software stored these readings for every set of testing conditions. Changing the temperature, humidity and depth from the pad's surface where measurements are made changed the test conditions. These data were analyzed statistically to determine the behavior of the pad. This research was part of a larger research effort that provided the statistical tool required to determine the uniformity of a CMP pad.