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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.
31

ACTIVE SUSPENSION CONTROL WITH DIRECT-DRIVE TUBULAR LINEAR BRUSHLESS PERMANENT-MAGNET MOTOR

Lee, Seungho 16 January 2010 (has links)
Recently, active suspension has been applied to many commercial automobiles. To develop the control algorithm for active suspension, a quarter-car test bed was built by using a direct-drive tubular linear brushless permanent-magnet motor (LBPMM) as a force-generating component. Two accelerometers and a linear variable differential transformer (LVDT) are used in this quarter-car test bed. Three pulse-width-modulation (PWM) amplifiers supply the currents in three phases. Simulated road disturbance is generated by a rotating cam. Modified lead-lag control, linear-quadratic (LQ) servo control with a Kalman filter, and the fuzzy control methodologies were implemented for active-suspension control. In the case of fuzzy control, asymmetric membership functions were introduced. This controller could attenuate road disturbance by up to 78%. Additionally, a sliding-mode controller (SMC) is developed with a different approach from the other three control methodologies. While SMC is developed for the position control, the other three controllers are developed for the velocity control. SMC showed inferior performance due to the drawback of the implemented chattering-proof method. Both simulation and experimental results are presented to demonstrate the effectiveness of these four control methodologies.
32

Fuzzy-PSO based obstacle avoidance and path planning for mobile robot

Chen, Guan-Yan 03 September 2012 (has links)
In recent years, due to the international competition, soaring cost of land and personnel, aging population, low birth rate¡Ketc, resulting in the recession of the competitiveness of traditional industries in Taiwan. Manpower is needed to monitor the manufacturing process, however, only a worker can¡¦t endure such kind of repetitive workload; on the other hand, it¡¦s not economic to hire more workers to share the workload. Therefore, we expect robots to replace human resources in the manufacturing process. With the advance of science and technology, the mobile robot must equip intelligent judgments. For instance, obstacle avoidance, a way to avoid damage being caused by collision with the obstacles. In general, there are some tables, chairs and the electrical equipment in the office. In the dynamic obstacles case, the robot is effective and immediate response to determine while the people are walking, the staff members to maintain a work efficiency, and security through complex environments. It is the primary topics of discussion. Another important function is path planning, such as the patrol, and the global path planning. Let the mobile robot reach the specified target successfully. In the remote monitoring case, let users know the actual situation of the mobile robot. For example, records of patrol information and specify the action type to move. Therefore, this thesis presents a project of the indoor integrated intelligent mobile robots, including obstacle avoidance, path planning, and remote monitoring of the unknown environment.
33

ACTIVE SUSPENSION CONTROL WITH DIRECT-DRIVE TUBULAR LINEAR BRUSHLESS PERMANENT-MAGNET MOTOR

Lee, Seungho 16 January 2010 (has links)
Recently, active suspension has been applied to many commercial automobiles. To develop the control algorithm for active suspension, a quarter-car test bed was built by using a direct-drive tubular linear brushless permanent-magnet motor (LBPMM) as a force-generating component. Two accelerometers and a linear variable differential transformer (LVDT) are used in this quarter-car test bed. Three pulse-width-modulation (PWM) amplifiers supply the currents in three phases. Simulated road disturbance is generated by a rotating cam. Modified lead-lag control, linear-quadratic (LQ) servo control with a Kalman filter, and the fuzzy control methodologies were implemented for active-suspension control. In the case of fuzzy control, asymmetric membership functions were introduced. This controller could attenuate road disturbance by up to 78%. Additionally, a sliding-mode controller (SMC) is developed with a different approach from the other three control methodologies. While SMC is developed for the position control, the other three controllers are developed for the velocity control. SMC showed inferior performance due to the drawback of the implemented chattering-proof method. Both simulation and experimental results are presented to demonstrate the effectiveness of these four control methodologies.
34

Hybrid Fuzzy PID Controller with Adaptive Genetic Algorithms for the Position Control of Linear Motors

Chen, Yi-Kuang 01 July 2003 (has links)
Abstract This thesis studies on the design of hybrid fuzzy PID controller via genetic algorithms and the position control of linear DC motors. Due to the high precision and high speed positioning ability, linear DC motors have been widely used in many fields. However, with the higher requirements of positioning accuracy, the effect of nonlinear friction becomes very significant. Because of the large difference between dynamic friction in macrodynamic region and static friction in microdynamic region, we design the two-stage controller for positioning in macrodynamic and microdynamic stage individually. In the macrodynamic stage, we use the hybrid fuzzy PID controller and finding the optimal membership functions and scaling factors of the controller via adaptive genetic algorithms to enhance performance of the system. A novel formula for calculating adaptive crossover and mutation rate is also presented. Since it is not easy to establish a precise static friction model in the microdynamic region, the relay feedback method is adopted to design PID controllers. Finally, through computer simulations and experiments, it is obviously that the performance of the proposed controllers is satisfactor
35

Modeling and Control of Non-contacting Steel Plate Conveyance System

Lin, Sheng-Yang 25 August 2009 (has links)
A non-contacting steel plate conveyance system based on the linear induction motor scheme, which can provide lift and propulsive forces simultaneously, is proposed. It has the features of high power density, direct drive, simple mechanical structure, and being able to reduce the operation noise. A magnetic equivalent circuit method and electromagnetic theory incorporating with 3-D finite element analysis are involved to investigate the static and quasi-dynamic properties and confirm the electrical and mechanical designs. To realize the dynamic behavior and develop the closed-loop control, a proper stationary reference frame transformation of the system voltage equations is also introduced. By considering the practical operational environment, a fuzzy-based control structure integrated with remote optical measurement system has been established and implemented by a DSP-based controller combined with required peripheral circuits. The experimental results show the applicability of such control strategies. With the systematic procedures for design, analysis, and control provided in this dissertation, implementation feasibility of the proposed system can be conveniently demonstrated.
36

Synthesizing the sit-to-stand movement using fuzzy logic-based control and a simple biomechanical model

Prinz, Robert K. 24 August 2010 (has links)
This thesis puts forward a fuzzy logic-based control strategy for artificially reproducing the sit-to-stand movement. The aim of this work is to contribute to the machine intelligence being developed for advanced mobility support devices; and specifically, those which are able to assist the mobility impaired user with the sit-to-stand task. Three fuzzy logic controllers were designed. The first controller seeks to move the model into the “most stable” configuration. The second seeks to move the model toward the goal configuration (i.e., standing). And the third combines the output from the first two controllers to produce a unified control action. Each controller was implemented and tested in software using Mathwork’s Matlab(TM). The results of the software simulation were compared against motion capture data taken from a single healthy male test subject. The automated controller was shown to produce a movement very similar to the natural sit-to-stand movement.
37

Αναβάθμιση εξοπλισμού και λογισμικού ασαφούς ελεγκτή συστήματος βιολογικού αντιδραστήρα

Προκόπης, Κωνσταντίνος 01 November 2010 (has links)
Η παρούσα διπλωματική μελέτη έχει ως αντικείμενο την αναβάθμιση της εργαστηριακής άσκησης "Έμπειρος και ασαφής έλεγχος βιολογικού αντιδραστήρα" του εργαστηρίου Γενικής Ηλεκτροτεχνίας και Τομέα Συστημάτων Αυτόματου Ελέγχου. Η αναβάθμιση του εξοπλισμού περιλαμβάνει την αντικατάσταση του παλιού προσωπικού υπολογιστή (PC) και του παλιού προγραμματιζόμενου λογικού ελεγκτή (PLC) με νέας γενιάς αντίστοιχα. Η αναβάθμιση του λογισμικού αφορά την ανάπτυξη της παραπάνω εργαστηριακής εφαρμογής με το λογισμικό Fuzzy Control V6++. Το παρόν έγγραφο είναι χωρισμένο σε έξι κεφάλαια στα οποία παρουσιάζονται οι βασικές έννοιες και δομές των συστημάτων βιολογικού καθαρισμού καθώς και οι βασικές έννοιες της ασαφούς λογικής, των ασαφών ελεγκτών και των νευρωνικών δικτύων χωρίς όμως να στέκεται τόσο στα στοιχεία της θεωρίας. Προσπαθήσαμε δηλαδή να δώσουμε στην εργασία αυτή τη μορφή ενός εγχειριδίου με την εκτενή παρουσίαση όλων των βημάτων και των προβλημάτων που ακολουθήσαμε και αντιμετωπίσαμε στο εργαστηριακό περιβάλλον για την ανάπτυξη του ασαφούς ελεγκτή με το νέο υλικό (λογισμικό και εξοπλισμό). / --
38

Hardware Reconfigurável para Controladores Nebulosos. / Reconfigurable hardware for fuzzy controllers.

Paulo Renato de Souza e Silva Sandres 22 February 2013 (has links)
Controle de processos é uma das muitas aplicações que aproveitam as vantagens do uso da teoria de conjuntos nebulosos. Nesse tipo de aplicação, o controlador é, geralmente, embutido no dispositivo controlado. Esta dissertação propõe uma arquitetura reconfigurável eficiente para controladores nebulosos embutidos. A arquitetura é parametrizável, de tal forma, que permite a configuração do controlador para que este possa ser usado na implementação de qualquer aplicação ou modelo nebuloso. Os parâmetros de configuração são: o número de variáveis de entrada (N); o número de variáveis de saída (M); o número de termos linguísticos (Q); e o número total de regras (P). A arquitetura proposta proporciona também a configuração das características que definem as regras e as funções de pertinência de cada variável de entrada e saída, permitindo a escalabilidade do projeto. A composição das premissas e consequentes das regras são configuráveis, de acordo com o controlador nebuloso objetivado. A arquitetura suporta funções de pertinência triangulares, mas pode ser estendida para aceitar outras formas, do tipo trapezoidal, sem grandes modificações. As características das funções de pertinência de cada termo linguístico, podem ser ajustadas de acordo com a definição do controlador nebuloso, permitindo o uso de triângulos. Virtualmente, não há limites máximos do número de regras ou de termos linguísticos empregados no modelo, bem como no número de variáveis de entrada e de saída. A macro-arquitetura do controlador proposto é composta por N blocos de fuzzificação, 1 bloco de inferência, M blocos de defuzzificação e N blocos referentes às características das funções de pertinência. Este último opera apenas durante a configuração do controlador. A função dos blocos de fuzzificação das variáveis de entrada é executada em paralelo, assim como, os cálculos realizados pelos blocos de defuzzificação das variáveis de saída. A paralelização das unidades de fuzzificação e defuzzificação permite acelerar o processo de obtenção da resposta final do controlador. Foram realizadas várias simulações para verificar o correto funcionamento do controlador, especificado em VHDL. Em um segundo momento, para avaliar o desempenho da arquitetura, o controlador foi sintetizado em FPGA e testado em seis aplicações para verificar sua reconfigurabilidade e escalabilidade. Os resultados obtidos foram comparados com os do MATLAB em cada aplicação implementada, para comprovar precisão do controlador. / Process control is one of the many applications that benefits from fuzzy control. In this kind of application, the controller is usually embedded in the controlled device. This dissertation proposes a reconfigurable architecture for efficient embedded fuzzy controllers. The architecture is customizable, as it allows the controller configuration to be used to implement any fuzzy model. The configuration parameters are: the number of input variables (N); the number of output variables (M); the number of linguistic terms (Q); and the total number of rules (P). The proposed architecture also enables the configuration of the characteristics that define the rules and membership functions of each input and output variable, allowing for an optimal scalability of the project. The composition of the antecedent and consequent of the rules are configurable, according to the fuzzy model that is being implemented. A priori, the architecture supports triangular membership functions, but it can be extended to accommodate other forms, such as trapezium, without major modifications. The characteristics of the lines, forming the membership functions of the linguistic terms, can be adjusted according to the definition of the fuzzy model, allowing the use of non-isosceles and isosceles triangles. Virtually, there are no limits on the number of rules or linguistic terms used in the model, as well as the number of input and output variables. The macro-architecture of the proposed controller is composed of N fuzzification blocks, 1 inference block, M defuzzification blocks and N blocks to handle the characteristics of the membership functions. This block operates only during the controller setup. The work done by the fuzzification blocks of the input variables is executed in parallel, as well as the computation performed by the defuzzification blocks of the output variables. The duplication of the fuzzification and defuzzification blocks accelerates the process of yielding the final response of the controller. Several simulations were performed to verify the correct operation of the controller, which is specified in VHDL. In a second stage, to evaluate the controller performance, the architecture was synthesized into a FPGA and tested with six applications to verify the reconfigurability and scalability of the design. The results obtained were compared with the ones obtained from MATLAB for each of the implemented applications, to demonstrate the accuracy of the controller.
39

Handover Optimization in GSM

Pavski, Johann Joachim January 2015 (has links)
In telecommunications in general and in GSM in particular, the handover is a feature that guarantees a smooth transition of a call from one base station - that is for the purpose of this project an antenna - to another. In the recent ten years, the amount of data traffic through mobile telecommunications has doubled annually, putting an enormous strain on the network and forcing operators to upgrade with more and more base stations and new features. Although 3G and 4G are responsible for data traffic in most countries, GSM still provides more than 80% of the coverage for mobile devices around the world. Due to the increase in data traffic, 3G and 4G need to use more and more frequencies at the expense of GSM. An optimization of the GSM network is thus vital. In this project, we research two methods to automatically choose the parameters of interest (PoI) that govern the handover feature in each cell which is, roughly speaking, the area of coverage of one antenna. In one of these methods, the choice of cell- and cell-to-cell-specific parameters has its origins in control theory while the other method is based on mathematical optimization. In the mathematical sense, our goal is to optimize the quality of service over PoIs. Extensive simulations have been run using these PoIs in order to evaluate if and how the two different methods can effectively be used in reality. Several useful insights have been gained that will provide the basis for future work. The optimization approach in particular has proved to deliver good results within the limitations of the simulated environment used for testing.
40

Controle para um veículo aéreo não tripulado do tipo quadricóptero

Dantas, Flávia Elionara Freire 17 February 2017 (has links)
Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-06-27T20:40:29Z No. of bitstreams: 1 FláviaEFD_DISSERT.pdf: 4838703 bytes, checksum: cb75ca0f24038306bbea559a45db472e (MD5) / Rejected by Vanessa Christiane (referencia@ufersa.edu.br), reason: Corrigir referência on 2017-07-03T12:20:16Z (GMT) / Submitted by Lara Oliveira (lara@ufersa.edu.br) on 2017-07-04T16:12:28Z No. of bitstreams: 1 FláviaEFD_DISSERT.pdf: 4838703 bytes, checksum: cb75ca0f24038306bbea559a45db472e (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T16:56:52Z (GMT) No. of bitstreams: 1 FláviaEFD_DISSERT.pdf: 4838703 bytes, checksum: cb75ca0f24038306bbea559a45db472e (MD5) / Approved for entry into archive by Vanessa Christiane (referencia@ufersa.edu.br) on 2017-07-04T17:02:49Z (GMT) No. of bitstreams: 1 FláviaEFD_DISSERT.pdf: 4838703 bytes, checksum: cb75ca0f24038306bbea559a45db472e (MD5) / Made available in DSpace on 2017-07-04T17:02:57Z (GMT). No. of bitstreams: 1 FláviaEFD_DISSERT.pdf: 4838703 bytes, checksum: cb75ca0f24038306bbea559a45db472e (MD5) Previous issue date: 2017-02-17 / Research on Unmanned Aerial Vehicles (UAVs) has been intensified since the 2000s with the aim of replacing manned vehicles. Its maneuverability makes it capable of handling various types of applications such as surveillance of a particular area, inspection of structures, in difficult to access environments, among others. When the first research began, this type of aerial vehicle was only used for military applications, but at the moment they are studied for other applications; the studies focus on control techniques for stability and flight autonomy. This work aimed the development of an altitude control and attitude of a UAV type quadrotor; the implementation was carried out on the Arduino platform and the flight tests indoors. Design of stability and height control, comparisons between two types of height control, PID (Proportional-Integral-Derivative) and Fuzzy in a Simulink® / MATLAB environment were performed / anos 2000, com o objetivo de substituir os veículos tripulados. Sua manobrabilidade o torna apto a lidar com diversos tipos de aplicações como vigilância de uma determinada área, inspeção de estruturas, em ambientes de difícil acesso, entre outros. Quando as primeiras pesquisas iniciaram, esse tipo de veículo aéreo era usado apenas para aplicações militares, mas atualmente são estudados para outras aplicações; os estudos se concentram em técnicas de controle para estabilidade e autonomia dos voos. Este trabalho objetiva o desenvolvimento de um controle de altitude e atitude de um VANT do tipo quadricóptero; a implementação foi realizada na plataforma Arduino e os testes de voo em ambientes fechados. Foi realizado o controle de estabilidade e de altura, comparações entre dois tipos de controle de altura, PID (Proporcional-Integral-Derivativo) e Fuzzy em ambiente Simulink®/MATLAB / 2017-06-27

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