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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

A high speed scanning system for vision based navigation/control of mobile robots

Rubtsov, Vasily January 1998 (has links)
One of the main problems in the design of mobile robots is the development of creating smart integrated information systems. These systems may include different type of sensors. Usually a CeD vision system is a necessary part for these systems. This thesis considers the design of a fast mechanical scanning system for a CCD vision system and the synthesis of the optimal control for this system. The mathematical model of the transport subsystem for mobile robots subjected to an external disturbance is created. The correctness of this model is proved on the base of simulation and experimental results. Regression coefficients are calculated and an estimate of model accuracy is carried out. The approach of power calculation for the actuators for the fast mechanical scanning system is considered. Implementation of this approach extends the use of a general mathematical model of the transport subsystem of the mobile robot and as such considerably reduces the design time. The main features for estimation of external disturbances are determined. Limitations of implementation of some technical solutions for mobile robot sensors are defined according to an analysis conducted of different factors for external disturbances. Di~erent kinematic schemes of the scanning systems have been analysed in this thesis. Practical recommendations of the kinematic scheme used in scanning systems are given. The essential features of a kinematic scheme for the fast mechanical scanning system have been developed and verified. A method for the solution of the inverse kinematics of a 3 degree of freedom scanning system in terms of velocities and in accelerations is presented. This method is utilised for formulating optimal control for the fast mechanical scanning system. 11 v ASlLY RUBrsov PHD· THESIS The algorithms of fast scanning have been produced for the different types of the sensors. The limitations for the practical realisations for these algorithms are considered in this thesis. The optimal control algorithms for the developed scanning system are produced. This control minimises the sum of instant powers of the scanning system actuators. A practical algorithm has been derived utilising the control scheme structure developed theoretically. The capability of this control algorithm has been proved by experimental study. Advantages of this developed control algorithm for 3 degree scanning system has been proven by experimentation.
2

Desenvolvimento e avaliação de pulverizador florestal com detecção eletrônica de plantas daninhas e aplicação em doses variáveis

Queiroz, Carolina Aparecida de Souza [UNESP] 21 June 2005 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:31:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-06-21Bitstream added on 2014-06-13T19:20:42Z : No. of bitstreams: 1 queiroz_cas_dr_botfca.pdf: 1726024 bytes, checksum: 883933fa5f6f17b9dfa145a7d0f78e8c (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / As florestas plantadas de eucalipto no Brasil representam grande importância ambiental, social e econômica, além de possuírem o maior potencial de produção florestal do mundo. Contudo, em meio aos tratos culturais dessas florestas, as aplicações de herbicida ainda apresentam-se pouco desenvolvidas em relação ao manejo de plantas daninhas nos plantios, principalmente no que diz respeito à quantidade de herbicida que é aplicada para efetivo controle das infestações. Logo, visando trazer benefícios à tecnologia de aplicação de herbicida no setor florestal, o presente trabalho teve como objetivos: (i) desenvolver e avaliar um pulverizador destinado à aplicação de herbicidas em florestas plantadas de eucalipto, capaz de efetuar aplicação de dose variada em tempo real, proporcionada por um sistema eletrônico de controle comandado por sensores ópticos (Weedseeker ); (ii) avaliar um sistema alternativo de detecção de plantas daninhas por meio de análise de imagens. O pulverizador desenvolvido foi constituído por duas barras aplicadoras que proporcionam o fracionamento da dose de herbicida, sendo uma munida de seis sensores e válvulas solenóides que possibilitam a aplicação localizada, realizada de maneira independente por 6 pontas de pulverização, e outra dotada de quatro pontas que são utilizadas para a aplicação de doses constantes em 100% da área. Em relação ao pulverizador desenvolvido foram avaliados, em comparação a um pulverizador de barra compacta protegida convencional, dados de consumo de calda, controle de plantas daninhas utilizando-se diferentes fracionamentos de dose de herbicida, dados referentes a funcionalidade a campo, resistência estrutural, desempenho operacional e custos das pulverizações. Em relação ao sistema alternativo de detecção de plantas daninhas por análise de imagens, foram avaliados dados... / The Brazilian planted forests of Eucalyptus represent great environmental, social and economic importance, besides having the greatest potential of production in the world. However, among the maintenance activities of these forests, the herbicide application is an activity not very developed, mainly about the right amount of herbicide to apply. Therefore, aiming to obtain benefits to application technology of herbicides in forestry, this study had as objectives: (i) to develop and to evaluate a sprayer destined to the commercial application of herbicides in planted forests of Eucalyptus, able to apply on line variable rate provided by a sensor system, assigned optic sensor (Weedseeker ); (ii) to evaluate an alternative system of weed detection based on image analysis. The developed sprayer is constituted by two booms that provide the variable dose application. One of them armed of six sensors and solenoids valves that permit the site-specific application by each nozzle and the other one armed of four nozzles that are used to the application of constant dose on 100% of the applied area. In relation to the developed sprayer it was evaluated in comparison to a conventional sprayer, data of mixture amount spent, weed control at variable doses application, structural functionality, structural resistance, working performance and costs of the herbicide application. The referring tests to the image sensor system, it was evaluated data that represent the capacity of the system in detecting plants with different foliage area and architecture of leaves in three different surfaces. The results showed that the developed sprayer provided 24,1% of herbicide economy without reducing the weed control. The new structure of the sprayer became adapted to the conditions of planted forests of Eucalyptus and the profit, in comparison to the conventional sprayer, was obtained... (Complete abstract, click electronic access below)
3

Desenvolvimento e avaliação de pulverizador florestal com detecção eletrônica de plantas daninhas e aplicação em doses variáveis /

Queiroz, Carolina Aparecida de Souza, 1976- January 2005 (has links)
Orientador: Ulisses Rocha Antuniassi / Banca: Carlos Gilberto Raetano / Banca: Kleber Pereira Lanças / Banca: Otávio Jorge G. Abi Saab / Banca: Marco Antonio Gandolfo / Resumo: As florestas plantadas de eucalipto no Brasil representam grande importância ambiental, social e econômica, além de possuírem o maior potencial de produção florestal do mundo. Contudo, em meio aos tratos culturais dessas florestas, as aplicações de herbicida ainda apresentam-se pouco desenvolvidas em relação ao manejo de plantas daninhas nos plantios, principalmente no que diz respeito à quantidade de herbicida que é aplicada para efetivo controle das infestações. Logo, visando trazer benefícios à tecnologia de aplicação de herbicida no setor florestal, o presente trabalho teve como objetivos: (i) desenvolver e avaliar um pulverizador destinado à aplicação de herbicidas em florestas plantadas de eucalipto, capaz de efetuar aplicação de dose variada em tempo real, proporcionada por um sistema eletrônico de controle comandado por sensores ópticos (Weedseeker ); (ii) avaliar um sistema alternativo de detecção de plantas daninhas por meio de análise de imagens. O pulverizador desenvolvido foi constituído por duas barras aplicadoras que proporcionam o fracionamento da dose de herbicida, sendo uma munida de seis sensores e válvulas solenóides que possibilitam a aplicação localizada, realizada de maneira independente por 6 pontas de pulverização, e outra dotada de quatro pontas que são utilizadas para a aplicação de doses constantes em 100% da área. Em relação ao pulverizador desenvolvido foram avaliados, em comparação a um pulverizador de barra compacta protegida convencional, dados de consumo de calda, controle de plantas daninhas utilizando-se diferentes fracionamentos de dose de herbicida, dados referentes a funcionalidade a campo, resistência estrutural, desempenho operacional e custos das pulverizações. Em relação ao sistema alternativo de detecção de plantas daninhas por análise de imagens, foram avaliados dados... (Resumo completo, clicar acesso eletrônio abaixo) / Abstract: The Brazilian planted forests of Eucalyptus represent great environmental, social and economic importance, besides having the greatest potential of production in the world. However, among the maintenance activities of these forests, the herbicide application is an activity not very developed, mainly about the right amount of herbicide to apply. Therefore, aiming to obtain benefits to application technology of herbicides in forestry, this study had as objectives: (i) to develop and to evaluate a sprayer destined to the commercial application of herbicides in planted forests of Eucalyptus, able to apply on line variable rate provided by a sensor system, assigned optic sensor (Weedseeker ); (ii) to evaluate an alternative system of weed detection based on image analysis. The developed sprayer is constituted by two booms that provide the variable dose application. One of them armed of six sensors and solenoids valves that permit the site-specific application by each nozzle and the other one armed of four nozzles that are used to the application of constant dose on 100% of the applied area. In relation to the developed sprayer it was evaluated in comparison to a conventional sprayer, data of mixture amount spent, weed control at variable doses application, structural functionality, structural resistance, working performance and costs of the herbicide application. The referring tests to the image sensor system, it was evaluated data that represent the capacity of the system in detecting plants with different foliage area and architecture of leaves in three different surfaces. The results showed that the developed sprayer provided 24,1% of herbicide economy without reducing the weed control. The new structure of the sprayer became adapted to the conditions of planted forests of Eucalyptus and the profit, in comparison to the conventional sprayer, was obtained... (Complete abstract, click electronic access below) / Doutor

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