Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011. / ENGLISH ABSTRACT: This thesis presents work completed on the design of control and vision components for use in a monocular vision-based human-following robot. The use of vision in a controller feedback loop is referred to as vision-based or visual servo control. Typically, visual servo techniques can be categorised into imagebased visual servoing and position-based visual servoing. This thesis discusses each of these approaches, and argues that a position-based visual servo control approach is more suited to human following. A position-based visual servo strategy consists of three distinct phases: target recognition, target pose estimation and controller calculations. The thesis discusses approaches to each of these phases in detail, and presents a complete, functioning system combining these approaches for the purposes of human following. Traditional approaches to human following typically involve a controller that causes platforms to navigate directly towards targets, but this work argues that better following performance can be obtained through the use of a controller that incorporates target orientation information. Although a purely direction-based controller, aiming to minimise both orientation and translation errors, suffers from various limitations, this thesis shows that a hybrid, gain-scheduling combination of two traditional controllers offers better targetfollowing performance than its components. In the case of human following the inclusion of target orientation information requires that a definition and means of estimating a human’s orientation be available. This work presents a human orientation measure and experimental results to show that it is suitable for the purposes of wheeled platform control. Results of human following using the proposed hybrid, gain-scheduling controller incorporating this measure are presented to confirm this. / AFRIKAANSE OPSOMMING: Die ontwerp van ’n visiestelsel en beheer-komponente van ’n enkel-kamera robot vir die volging van mense word hier aangebied. Die gebruik van visuele terugvoer in die beheerlus word visie-gebaseerde of visuele servobeheer genoem. Visuele servobeheer tegnieke kan tipies onderskei word tussen beeld-gebaseerde servobeheer en posisie-gebaseerde visuele servobeheer. Altwee benaderings word hier bespreek. Die posisie-gebaseerde benadering word aanbeveel vir die volging van mense. Die posisie-gebaseerde servobeheertegniek bestaan uit drie duidelike fases: teiken herkenning, teiken oriëntasie bepaling en die beheerder berekeninge. Benaderings tot elk van hierdie fases word hier in detail bespreek. Dan word ’n volledige funksionele stelsel aangebied wat hierdie fases saamvoeg sodat mense gevolg kan word. Meer tradisionele benaderings tot die volging van mense gebruik tipies ’n beheerder wat die platvorm direk laat navigeer na die teikens, maar hier word geargumenteer dat beter werkverrigting verkry kan word deur ’n beheerder wat die teiken oriëntasie inligting ook gebruik. ’n Suiwer rigting-gebaseerde beheerder, wat beide oriëntasie en translasie foute minimeer, is onderhewig aan verskeie beperkings. Hier word egter aangetoon dat ’n hibriede, aanwinsskedulerende kombinasie van die twee tradisionele beheerders beter teikenvolging werkverrigting bied as die onderliggende twee tegnieke. In die geval van die volging van mense vereis die insluiting van teiken oriëntasie inligting dat ’n definisie van die persoon se oriëntasie beskikbaar is en dat dit geskat kan word. ’n Oriëntasie maatstaf vir mense word hier aangebied en dit word eksperimenteel getoon dat dit geskik is om ’n platvorm met wiele te beheer. Die resultate van die volging van mense wat die voorgestelde hibriede, aanwins-skedulerende beheerder gebruik, met hierdie maatstaf, word ter ondersteuning aangebied.

Submitted by CARLOS ALEXIS ALVARADO SILVA (carlosalvaradosilva@gmail.com) on 2016-09-14T17:46:58Z No. of bitstreams: 1 dissertação final CARLOS ALVARADO.pdf: 3455623 bytes, checksum: 4fe5a62f068f2bf001ce3b1fdc1681ef (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-09-14T21:51:44Z (GMT) No. of bitstreams: 1 silva_caa_me_guara.pdf: 3455623 bytes, checksum: 4fe5a62f068f2bf001ce3b1fdc1681ef (MD5) / Made available in DSpace on 2016-09-14T21:51:44Z (GMT). No. of bitstreams: 1 silva_caa_me_guara.pdf: 3455623 bytes, checksum: 4fe5a62f068f2bf001ce3b1fdc1681ef (MD5) Previous issue date: 2016-07-04 / Agencia Nacional de Petróleo (ANP) / Controlar a pressão de poços petrolíferos durante a perfuração pode ser um dos processos mais complexos e perigosos da etapa de exploração. O sistema de perfuração varia constantemente e aleatoriamente, isto principalmente, devido à mudança da profundidade de perfuração, a qual faz variar outros parâmetros do processo. Assim, a aplicação de um controle variante no tempo torna-se necessário. Este estudo propõe o projeto de um controlador Gain Scheduling (GS) no controle da pressão no fundo de poços durante a perfuração. Este controlador GS consiste na sintonia dos ganhos relacionados aos diferentes pontos operacionais, para este caso, a profundidade do poço. Primeiro, apresentam-se as teorias a serem utilizadas durante o desenvolvimento do trabalho. Segundo, obtém-se o modelo matemático do processo o qual se fundamenta na mecânica dos fluidos. Da linearização do modelo, a função de transferência resultante apresenta um elemento integrador o que faz que a dinâmica do processo seja difícil de manipular. Também se adiciona um tempo de atraso, o que torna mais complexo o controle do processo. Na terceira parte, utilizaram-se três tipos de metodologias IMC (Internal Model Control) para sintonizar os ganhos do controlador PID (Proporcional, Integral e Derivativo) para diferentes profundidades de perfuração procurando o melhor desempenho, estabilidade e robustez do sistema. Finalmente, escolhe-se a estratégia de melhor desempenho (IMC de dois graus de liberdade) para especificar e montar a tabela do controlador GS, o qual é avaliado mediante simulações de problemas que geralmente ocorrem durante a perfuração, considerados como distúrbios, que verificam a sua viabilidade. Também, os resultados do sistema controlado por GS são comparados com os resultados de um outro controlador do tipo adaptativo de modelo de referência (CAMR). Verificando também melhor desempenho o controlador GS diante do CAMR. / Controlling the pressure of oil wells during drilling can be one of the most complex and dangerous processes of exploration stage. The drilling system is constantly end randomly changing due, among other things, the drilling depth, which varies other process parameters, accordingly to apply a time variant control becomes necessary. This study proposes the design of a Gain Scheduling controller to control the pressure at the bottom of wells during drilling. The GS controller is based on the corresponding tuning gains at different operating points in this case, the depth. First, presents the theories that will be used during development work. In the second part, was obtained a mathematical model of the process which is based on fluid mechanics. In the linearization of the, the final transfer function presents an integrating element which makes the process dynamics more difficult to handle. It becomes even more complex in the presence of time delay. In the third part, three IMC controllers’ types were used to tuning the PID (Proportional, Integral and Derivative) controller gains for different depths of drilling looking for the best performance, stability and robustness. Finally, was chose the best performing strategy (IMC of two degrees of freedom) to specify and assemble the GS controller table, which is evaluated by simulations of problems that usually occur during drilling, considered as disturbances, which check its viability. Also, the results of the controlled GS system are compared with the results of another adaptive controller model of model reference (MRAC). Also verifying that the GS controller presents better performance than MRAC. / PRH48/ANP: 48610.009725/2013