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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.
11

Extensão do iterative feedback tuning para sistemas em cascata com aplicação em controle de quadricópteros

Tesch, Douglas Antunes January 2016 (has links)
Os métodos de controle baseados em dados têm como diferencial utilizar os dados coletados de experimentos para realizar a sintonia do controlador de uma forma direta e sem utilizar nenhum modelo do processo. Um dos métodos já consagrados é o conhecido Iterative Feedback Tuning, método este caracterizado como um algoritmo iterativo de otimização que busca a minimização do critério de desempenho norma H2. O presente trabalho propõe uma extensão baseada no clássico algoritmo Iterative Feedback Tuning para sistemas em formato cascata com duas malhas de controle. O formato cascata com duas malhas de controle é uma estrutura comum e muito utilizada em aplicações de cunho industrial. A sintonia deste tipo de estrutura em metodologias clássicas de controle envolve geralmente duas etapas. Primeiramente a malha interna é sintonizada para então posteriormente a malha externa. A vantagem do método de controle baseado em dados proposto está em realizar a sintonia de ambas as malhas de forma simultânea e concomitantemente. É escolhida como aplicação um veículo aéreo não tripulado com quatro rotores, mais conhecido como quadricóptero. Esta aplicação tem uma dinâmica complexa, uma vez que o sistema é classificado como sendo não-linear e multivariável, algo demonstrado através do equacionamento dinâmico do quadricóptero que é apresentado. Uma série de simulações e experimentos práticos são apresentadas com o intuído de demonstrar a dinâmica descrita no modelo e também demonstrar a aplicação do algoritmo Cascade Iterative Feedback Tuning para os mesmos. / The methods of data-driven control have the distinction to use the data collected from experiments to perform the tuning of the controller directly and without using any process model. One method already established is the Iterative Feedback Tuning, this method is characterized as an iterative optimization algorithm that aims to minimize the H2 norm performance criterion. The present work proposes an extension based on the classical Iterative Feedback Tuning algorithm for cascade systems with two control loops. The cascade format with two loops is a common structure and widely used in industrial applications. In classical control methods, the tuning of this type of structure usually involves two steps. First, the inner loop is tuned and subsequently the outer loop. The advantage of the proposed data-driven control method is to perform this tuning of both controller simultaneously and concurrently. We choose as an application a unmanned aerial vehicle (UAV) with four rotors, better known as quadcopter. This application has a complex dynamic, since the system is classified as being non-linear and multivariable, demonstrated by the quadcopter dynamic equations. A series of simulations and practical experiments are presented to demonstrate the dynamicmodel described and also to validate the method CIFT algorithms.
12

Arquitetura baseada em agentes e auto-organizável para a manufatura

Cavalcante, André Luiz Duarte January 2012 (has links)
Este trabalho aborda os sistemas de montagem auto-organizados baseados em agentes para o ambiente industrial. Para isso, traz uma visão ampla dos paradigmas atuais para a manufatura que usam o conceito de agente e que promovem auto-organização, mas é focado no paradigma de sistemas de montagem e de produção evolutivos. Além da autoorganização, aspectos de auto-otimização nestes sistemas também são considerados. Portanto, este trabalho aborda os aspectos teóricos e práticos de sistemas evolutivos e, em particular, propõe uma plataforma multiagente que usa o conceito de agente mecatrônico para permitir o desenvolvimento de sistemas auto-organizados e que também possuam a capacidade de otimizar autonomamente algum recurso interno ao sistema. Um agente mecatrônico é uma entidade capaz de ação autônoma num sistema de manufatura, devido a uma decisão própria ou à solicitação de ação por outros agentes, e tal é conseguido através da definição e execução de funcionalidades pelos agentes mecatrônicos. A plataforma multiagente proposta foi implementada e validada no âmbito de um projeto da União Europeia o qual possui parceiros acadêmicos e industriais e visa a criação de sistemas evolutivos auto-organizados em um cenário industrial real. / This work deals with agent-based self-organized assembly systems for manufac– turing. Although the text aims to provide a comprehensive overview on current paradigms to manufactiuring systems development and execution that use the concept of agent and promote self-organization, the thesis main focus lies in evolvable production and assembly systems paradigms. Beyond self-organization, self-optimization aspects of evolvable systems are also considered. Therefore, this thesis discusses theoretical and practical aspects of evolvable systems and, in particular, develops a multi-agent platform that uses the mechatronic agent concept to enable the development of self-organized systems and has the capacity of autonomously to optimize some internal resource of the system. A mechatronic agent is an entity that is capable of autonomous action on a manufacturing system due to this own reasoning or by reacting to a requested action from other agents. The proposed platform was implemented and validated within the scope of a research project funded by the European Union that has both academic and industrial partners and it goals the building of self-organized evolvable assembly systems for a real industrial scenario.
13

Aspects of automatic train control

Milroy, Ian P. January 1980 (has links)
This thesis describes research and development. work carried out by the author into the control of traction and braking systems on rail vehicles. After a review of recent developments, the problem of. driving a train under minimum-energy control subject·to timetable and operational constraints is discussed. This is partitioned into two sections. Firstly, target time and velocities for key pOints on the journey are computed; these are communicated to or stored on the train, together with route and vehicle data. Secondly, an on-board digital system drives the train to each target according to control algorithms which incorporate a predictorcorrector module, whose function is to determine which of two criteria of performance is to be used (minimum-energy when running early or on-time, minimum-time when running late). Most of the thesis is devoted to the analysis and design of the train-borne control system. The general form of the optimal control (of tractive or braking effort) is determined by the application of Pontryagin's Maximum Principle over each section of the journey. However, the moments of transition between the various modes of control are calculated by a method which involves a lookahead model in the predictor module, rather than by iterative solution of the state and co-state equations . An important aspect of the design is the dynamic response of the braking SUb-system, which may include a substantial pneumatic transport lag within the control loop. S-plane and z-plane design procedures for the required discrete control algorithms to.achieve a specified transient response are derived. The thesis concludes with a chapter on the instrumentation required for the train-borne control system.
14

A Consensus-based Distributed Algorithm for Reconfiguration of Spacecraft Formations

Sonali Sinha Roy (9746630) 15 December 2020 (has links)
Spacecraft formation flying refers to the coordinated operation of a group of spacecraft with a common objective. While the concept has been in existence for a long time, practical fruition of the ideas was not possible earlier due to technological limitations. The topic has received widespread attention in the last decade, with the development of autonomous control, improved computational facilities and better communication technology. It allows a number of small, lightweight, economical spacecraft to work together to execute the function of a larger, heavier, more complex and expensive spacecraft. The primary advantage of such systems is that they are flexible, modular, and cost-effective.<div><br></div><div>The flexibility of formation flying and other derived concepts comes from the fact that the units are not physically attached, allowing them to change position or orientation when the need arises. To fully realize this possibility, it is important to develop methods for spatial reorganization. This thesis is an attempt to contribute to this development. </div><div><br></div><div>In this thesis, the reconfiguration problem has been formulated as a single system with multiple inputs and multiple outputs, while preserving the individuality of the agents to a certain degree. The agents are able to communicate with their neighbors by sharing information. In this framework, a distributed closed-loop stabilizing controller has been developed, that would drive the spacecraft formation to a target shape. An expression for the controller gain as a function of the graph Laplacian eigenvalues has also been derived. The practical applications of this work have been demonstrated through simulations</div>
15

Cooperative Perception in Multi-agent Systems

Gautham Vinod (11033205) 23 July 2021 (has links)
<div>This thesis presents work and simulations containing the use of Artificial Intelligence for Unmanned Aerial Vehicles in search and rescue and/or surveillance operations. The goal is to create a vision system that leverages Artificial Intelligence, mainly Deep Learning techniques to build a pipeline that enables fast and accurate classification of the environment of the robot. Deep Neural Networks are trained and tested on ’emergency situational data. Further, the power of this vision system is leveraged to extend the problem onto a multiagent system to handle fault tolerance. The multi-agent system is also made resilient to Byzantine malicious attacks to help improve the reliability of the system.</div><div><br></div><div>This thesis also shows the use of Artificial Intelligence for effective surveillance for defense related purposes. Tracking the GPS coordinates of a boat using only the video of the boat captured by a camera and the GPS coordinates of the camera itself is demonstrated. The solution was tested by the Department of Defense - Department of the Navy, Naval Information Warfare Center Pacific.</div>
16

Development of an Autonomous Multi-Agent Drone Protection and Apprehension System for Persistent Operations

Reed D Lamy (12463386) 28 April 2022 (has links)
<p> </p> <p>This work proposes a proof of concept along with a prototype of a multi-agent autonomous drone system that can be used to detect, and capture a intruding adversarial drone. The functional Counter Unmanned Aerial System (CUAS) prototype is used to convey the feasibility of a persistent multi-agent aerial protection and apprehension system by demonstrating important features of the mission through both simulation and field testing.<br> </p> <p> </p>
17

Enhanced Class 8 Truck Platooning via Simultaneous Shifting and Model Predictive Control

Ifeoluwa Jimmy Ibitayo (6845570) 13 August 2019 (has links)
<div>Class 8 trucks on average drive the most miles and consume the most fuel of any major vehicle category annually. Indiana specifically is the fifth busiest state for commercial freight traffic and moves $750 billion dollars of freight annually, and this number is expected to grow by 60% by 2040. Reducing fuel consumption for class 8 trucks would have a significant benefit on business and the proportional decrease in CO<sub>2</sub> would be exceptionally beneficial for the environment.</div><div><br></div><div>Platooning is one of the most important strategies for increasing class 8 truck fuel savings. Platooning alone can help trucks save upwards of 7% platoon average fuel savings on flat ground. However, it can be difficult for a platooning controller to maintain a desired truck separation during uncoordinated shifting events. Using a high-fidelity simulation model, it is shown that simultaneous shifting–having the follow truck shift whenever the lead truck shifts (unless shifting would cause its engine to overspeed or underspeed)–decreases maximum truck separation by 24% on a moderately challenging grade route and 40% on a heavy grade route.</div><div><br></div><div>Model Predictive Control (MPC) of the follow truck is considered as a means to reduce the distance the follow truck falls behind during uncoordinated shifting events. The result in simulation is a reduction in maximum truck separation of 1% on a moderately challenging grade route and 19% on a heavy grade route. However, simultaneous shifting largely alleviates the need for MPC for the sake of tracking for the follow truck.</div><div><br></div><div>A different MPC formulation is considered to dynamically change the desired set point for truck separation for routes through a strategy called Route Optimized Gap Growth (ROGG). The result in simulation is 1% greater fuel savings on a moderately challenging grade route and 7% greater fuel savings on a route with heavy grade for the follow truck.</div>
18

Distributed and Adaptive Target Tracking with a Sensor Network

Michael A. Jacobs (5929805) 10 June 2019 (has links)
<div>Ensuring the robustness and resilience of safety-critical systems from civil aviation to military surveillance technologies requires improvements to target tracking capabilities. Implementing target tracking as a distributed function can improve the quality and availability of information for end users. Any errors in the model of a target's dynamics or a sensor network's measurement process will result in estimates with degraded accuracy or even filter divergence. This dissertation solves a distributed estimation problem for estimating the state of a dynamical system and the parameters defining a model of that system.</div><div>The novelty of this work lies in the ability of a sensor network to maintain consensus on state and parameter estimates through local communications between sensor platforms.</div>
19

Análise do impacto da comunicação em redes wirelesshart no desempenho de sistemas de controle

Soto, Viyils Sangregorio January 2016 (has links)
Este trabalho analisa o uso do protocolo WirelessHART para a implementação de sistemas de controle em laço fechado. São discutidas possíveis arquiteturas de implementação de laços de controle, as quais se diferem basicamente pelo local na arquitetura do sistema de controle em rede em que o controlador será executado. Optou-se pela análise do comportamento do protocolo WirelessHART numa arquitetura que considera o módulo de controle localizado num dispositivo host, o qual se comunica via HART-UDP com o gateway da rede. Para a análise da proposta desta dissertação foram descritos os mecanismos necessários para a realização do laço de controle sobre uma rede WirelessHART real, em um ambiente que apresenta todas as características de uma instalação industrial. Os resultados obtidos mostram que, com a arquitetura proposta, o laço de controle apresenta latências não determinísticas. Para a realização deste trabalho, foram apresentados dois estudos de caso: (i) o controle de uma válvula comumente utilizada na indústria de petróleo; (ii) e um processo simulado, que considera um controlador baseado em eventos, onde o sinal de controle é calculado de acordo com os tempos de comunicação permitidos pela rede entre o controlador e o processo. Os resultados obtidos mostram que é possível efetuar controle apesar dos atrasos ocasionados pela rede, desde que sejam levados em conta estes atrasos no cálculo do sinal de controle, podendo assim mostrar há degradação no desempenho do sistema sob controle. / This work analyzes the use of WirelessHART protocol for the implementation of closed-loop control systems. It discusses possible architectures for implementing control loops, which differ by the location where the controller is executing. For the performance evaluation of the WirelessHART protocol behavior, an architecture that considers the control module located in a device, which communicates via Hart-UDP with the network gateway. The Experimental evaluations presented in this dissertation were performed in a setting that has all the characteristics of an industrial installation. The results showed that in the proposed architecture, the control loop has not deterministic latencies. Two case studies were carried on: (i) the control of a valve commonly used in oil and gas industrial applications; (ii) and a simulated process that considers an event-based controller where the control signal is calculated according to the communication time allowed by the network between the controller and the process. The results show that it is possible to perform control despite network delays, when taking into account the delays in the calculation of the control signal.
20

Análise do impacto da comunicação em redes wirelesshart no desempenho de sistemas de controle

Soto, Viyils Sangregorio January 2016 (has links)
Este trabalho analisa o uso do protocolo WirelessHART para a implementação de sistemas de controle em laço fechado. São discutidas possíveis arquiteturas de implementação de laços de controle, as quais se diferem basicamente pelo local na arquitetura do sistema de controle em rede em que o controlador será executado. Optou-se pela análise do comportamento do protocolo WirelessHART numa arquitetura que considera o módulo de controle localizado num dispositivo host, o qual se comunica via HART-UDP com o gateway da rede. Para a análise da proposta desta dissertação foram descritos os mecanismos necessários para a realização do laço de controle sobre uma rede WirelessHART real, em um ambiente que apresenta todas as características de uma instalação industrial. Os resultados obtidos mostram que, com a arquitetura proposta, o laço de controle apresenta latências não determinísticas. Para a realização deste trabalho, foram apresentados dois estudos de caso: (i) o controle de uma válvula comumente utilizada na indústria de petróleo; (ii) e um processo simulado, que considera um controlador baseado em eventos, onde o sinal de controle é calculado de acordo com os tempos de comunicação permitidos pela rede entre o controlador e o processo. Os resultados obtidos mostram que é possível efetuar controle apesar dos atrasos ocasionados pela rede, desde que sejam levados em conta estes atrasos no cálculo do sinal de controle, podendo assim mostrar há degradação no desempenho do sistema sob controle. / This work analyzes the use of WirelessHART protocol for the implementation of closed-loop control systems. It discusses possible architectures for implementing control loops, which differ by the location where the controller is executing. For the performance evaluation of the WirelessHART protocol behavior, an architecture that considers the control module located in a device, which communicates via Hart-UDP with the network gateway. The Experimental evaluations presented in this dissertation were performed in a setting that has all the characteristics of an industrial installation. The results showed that in the proposed architecture, the control loop has not deterministic latencies. Two case studies were carried on: (i) the control of a valve commonly used in oil and gas industrial applications; (ii) and a simulated process that considers an event-based controller where the control signal is calculated according to the communication time allowed by the network between the controller and the process. The results show that it is possible to perform control despite network delays, when taking into account the delays in the calculation of the control signal.

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