• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 99
  • 10
  • 7
  • 7
  • 6
  • 5
  • 5
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 173
  • 173
  • 42
  • 37
  • 29
  • 28
  • 24
  • 23
  • 20
  • 18
  • 17
  • 15
  • 15
  • 15
  • 14
  • 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.
141

Autonomous Docking of Electric Boat / Autonom tilläggning av elektrisk båt

BOCZAR, LUDVIG, PERNOW, JONATHAN January 2021 (has links)
In recreational boating, docking is one of the most stressful and accident prone situations. Due to the loss of maneuverability at low speeds, it is a procedure that requires experience. There are mainly two problems when it comes to autonomous docking of a boat, these are identifying a berth’s position as well as keeping the boat on its intended path and correcting any deviations. Autonomous docking in recreational boating is still quite uncommon, with companies still exploring different solutions. This thesis proposes a Model Predictive Control (MPC) system combined with Pulsed Coherent Radar technology, equipped on an under-actuated boat model, to achieve autonomous docking. A major part of this thesis was to evaluate the amount and placement of radar sensors, as well as determining whether these are suitable in a water environment. In order to test this, the sensors were placed alongside the hull of the boat. It was found that the placement of sensors had a bigger impact than the amount when it came to correctly detecting the position of a berth. Once the placement of sensors and the berth position algorithmhad been done, a closed-loop MPC was used. This controller got constant feedback of the boat’s position relative the berth, in order to calculate the thruster control inputs for the next time step. The developed autonomous docking system was then implemented on the boat which was tested in a swimming pool. The optimal radar configuration combined withMPC, made it possible to successfully dock a boat autonomously without any modification to the berth. / För fritidsbåtlivet är tilläggning en av demest stressfulla och olycksbenägna situationerna. På grund av förlust av manövrering vid låga hastigheter är det en procedur som kräver erfarenhet. Det finns främst två problem när det kommer till autonom tilläggning, det är att identifiera positionen av en brygga såväl som att hålla båten på den avsedda kursen och rätta till små avvikelser. Autonom tilläggning för fritidsbåtlivet är fortfarande rätt ovanligt och företag utforskar fortfarande olika lösningar. Denna avhandling föreslår ett Modellprediktivt Reglersystem (MPC) kombinerat med Pulserad Koherent Radarteknik som är utrustad på en underaktuerad båtmodell för att uppnå autonom tilläggning. En stor del av avhandlingen var att utvärdera antalet och placeringen av radarsensorer, såväl som att fastställa om dessa är lämpliga att användas i en vattenmiljö. För att undersöka detta placerades sensorerna längs med båtens skrov. Det konstaterades att placeringen av sensorer hade en större påverkan än mängden när det kom till att läsa av positionen av bryggan korrekt. När placeringen av sensorer och bryggpositionsalgoritmen var klar användes MPC med återkoppling. Denna regulator fick konstant återkoppling av båtens position relativt bryggan för att räkna ut styrsignal till motorerna för nästa tidssteg. Den utvecklade autonoma tilläggningen var sedan implementerad på båten som testades i en pool. Den optimala radarplaceringen kombinerat med MPC gjorde det möjligt att med framgång kunna lägga till båten autonomt utan modifiering av bryggan.
142

Electromechanical Design and Development of the Virginia Tech Roller Rig Testing Facility for Wheel-rail Contact Mechanics and Dynamics

Hosseinipour, Milad 28 September 2016 (has links)
The electromechanical design and development of a sophisticated roller rig testing facility at the Railway Technologies Laboratory (RTL) of Virginia Polytechnic and State University (VT) is presented. The VT Roller Rig is intended for studying the complex dynamics and mechanics at the wheel-rail interface of railway vehicles in a controlled laboratory environment. Such measurements require excellent powering and driving architecture, high-performance motion control, accurate measurements, and relatively noise-free data acquisition systems. It is critical to accurately control the relative dynamics and positioning of rotating bodies to emulate field conditions. To measure the contact forces and moments, special care must be taken to ensure any noise, such as mechanical vibration, electrical crosstalk, and electromagnetic interference (EMI) are kept to a minimum. This document describes the steps towards design and development of all electromechanical subsystems of the VT Roller Rig, including the powertrain, power electronics, motion control systems, sensors, data acquisition units, safety and monitoring circuits, and general practices followed for satisfying the local and international codes of practice. The VT Roller Rig is comprised of a wheel and a roller in a vertical configuration that simulate the single-wheel/rail interaction in one-fourth scale. The roller is five times larger than the scaled wheel to keep the contact patch distortion that is inevitable with a roller rig to a minimum. This setup is driven by two independent AC servo motors that control the velocity of the wheel and roller using state-of-the-art motion control technologies. Six linear actuators allow for adjusting the simulated load, wheel angle of attack, rail cant, and lateral position of the wheel on the rail. All motion controls are performed using digital servo drives, manufactured by Kollmorgen, VA, USA. A number of sensors measure the contact patch parameters including force, torque, displacement, rotation, speed, acceleration, and contact patch geometry. A unified communication protocol between the actuators and sensors minimizes data conversion time, which allows for servo update rates of up to 48kHz. This provides an unmatched bandwidth for performing various dynamics, vibrations, and transient tests, as well as static steady-state conditions. The VT Roller Rig has been debugged and commissioned successfully. The hardware and software components are tested both individually and within the system. The VT Roller Rig can control the creepage within 0.3RPM of the commanded value, while actively controlling the relative position of the rotating bodies with an unprecedented level of accuracy, no more than 16nm of the target location. The contact force measurement dynamometers can dynamically capture the contact forces to within 13.6N accuracy, for up to 10kN. The instantaneous torque in each driveline can be measured with better than 6.1Nm resolution. The VT Roller Rig Motion Programming Interface (MPI) is highly flexible for both programmers and non-programmers. All common motion control algorithms in the servo motion industry have been successfully implemented on the Rig. The VT Roller Rig MPI accepts third party motion algorithms in C, C++, and any .Net language. It successfully communicates with other design and analytics software such as Matlab, Simulink, and LabVIEW for performing custom-designed routines. It also provides the infrastructure for linking the Rig's hardware with commercial multibody dynamics software such as Simpack, NUCARS, and Vampire, which is a milestone for hardware-in-the-loop testing of railroad systems. / Ph. D.
143

Inverse optimal control for redundant systems of biological motion / Contrôle optimal inverse de systèmes de mouvements biologiques redondants

Panchea, Adina 10 December 2015 (has links)
Cette thèse aborde les problèmes inverses de contrôle optimal (IOCP) pour trouver les fonctions de coûts pour lesquelles les mouvements humains sont optimaux. En supposant que les observations de mouvements humains sont parfaites, alors que le processus de commande du moteur humain est imparfait, nous proposons un algorithme de commande approximative optimale. En appliquant notre algorithme pour les observations de mouvement humaines collectées: mouvement du bras humain au cours d'une tâche de vissage industrielle, une tâche de suivi visuel d’une cible et une tâche d'initialisation de la marche, nous avons effectué une analyse en boucle ouverte. Pour les trois cas, notre algorithme a trouvé les fonctions de coût qui correspondent mieux ces données, tout en satisfaisant approximativement les Karush-Kuhn-Tucker (KKT) conditions d'optimalité. Notre algorithme offre un beau temps de calcul pour tous les cas, fournir une opportunité pour son utilisation dans les applications en ligne. Pour la tâche de suivi visuel d’une cible, nous avons étudié une modélisation en boucle fermée avec deux boucles de rétroaction PD. Avec des données artificielles, nous avons obtenu des résultats cohérents en termes de tendances des gains et les critères trouvent par notre algorithme pour la tâche de suivi visuel d’une cible. Dans la seconde partie de notre travail, nous avons proposé une nouvelle approche pour résoudre l’IOCP, dans un cadre d'erreur bornée. Dans cette approche, nous supposons que le processus de contrôle moteur humain est parfait tandis que les observations ont des erreurs et des incertitudes d'agir sur eux, étant imparfaite. Les erreurs sont délimitées avec des limites connues, sinon inconnu. Notre approche trouve l'ensemble convexe de de fonction de coût réalisables avec la certitude qu'il comprend la vraie solution. Nous numériquement garanties en utilisant des outils d'analyse d'intervalle. / This thesis addresses inverse optimal control problems (IOCP) to find the cost functions for which the human motions are optimal. Assuming that the human motion observations are perfect, while the human motor control process is imperfect, we propose an approximately optimal control algorithm. By applying our algorithm to the human motion observations collected for: the human arm trajectories during an industrial screwing task, a postural coordination in a visual tracking task and a walking gait initialization task, we performed an open loop analysis. For the three cases, our algorithm returned the cost functions which better fit these data, while approximately satisfying the Karush-Kuhn-Tucker (KKT) optimality conditions. Our algorithm offers a nice computational time for all cases, providing an opportunity for its use in online applications. For the visual tracking task, we investigated a closed loop modeling with two PD feedback loops. With artificial data, we obtained consistent results in terms of feedback gains’ trends and criteria exhibited by our algorithm for the visual tracking task. In the second part of our work, we proposed a new approach to solving the IOCP, in a bounded error framework. In this approach, we assume that the human motor control process is perfect while the observations have errors and uncertainties acting on them, being imperfect. The errors are bounded with known bounds, otherwise unknown. Our approach finds the convex hull of the set of feasible cost function with a certainty that it includes the true solution. We numerically guaranteed this using interval analysis tools.
144

Kennwertorientierte Methoden zur Auswahl und Synthese von Bewegungsgesetzen für Motion-Control-Systeme

Speicher, Thorsten 04 October 2021 (has links)
Im Rahmen dieser Arbeit werden Methoden präsentiert, die Anwender bei der Auslegung von taktzeitoptimalen Bewegungen für typische Rast-in-Rast-Charakteristiken unter Verwendung von normierten Bewegungsgesetzen nach der VDI-Richtlinie 2143 unterstützen. Es wird eine Herangehensweise vorgestellt, die bei Vorgabe von kinematischen Bewegungsgrenzen zu verwenden ist. Führt dabei die resultierende Bewegung zu einer unzulässigen Erwärmung des Antriebs, lässt sich mit Hilfe anderer Werkzeuge die minimal mögliche und somit optimale Taktzeit effizient bestimmen.:1 Einleitung 2 Stand der Forschung 3 Grundlagen 4 Taktzeitoptimierung bei kinematischen Restriktionen 5 Taktzeitoptimierung bei thermischen Restriktionen 6 Anwendungsbeispiele 7 Zusammenfassung und Ausblick / This paper presents methods to help users design motions with ideal cycle times for rest in rest applications by using the normalized laws of motion according to the VDI guideline 2143. The approach shown is used for systems that are limited by their kinematic parameters. If the resulting movement leads to inadmissible heating of the drive, other tools are able to determine the minimal cycle time considering the thermal limit.:1 Einleitung 2 Stand der Forschung 3 Grundlagen 4 Taktzeitoptimierung bei kinematischen Restriktionen 5 Taktzeitoptimierung bei thermischen Restriktionen 6 Anwendungsbeispiele 7 Zusammenfassung und Ausblick
145

Critical evaluation and application of position sensorless control techniques for reluctance synchronous machines

Villet, Wikus Theo 04 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The position sensorless controllability of the reluctance synchronous machine (RSM) is investigated in this thesis with the focus on industry applications where variable and dynamic torque is required from startup up to rated speed. Two low speed as well as one medium to high speed position sensorless control (PSC) method for RSMs are investigated. These methods are extended to operate in the entire rated speed region with a hybrid PSC structure that makes use of phase locked-loop synchronisation and a hysteresis changeover method. It is shown in this thesis that PSC of the lateral rib rotor RSM is not possible from zero up to ± 0.2 p.u current. It is shown through finite element (FE) simulations that PSC of the ideal rotor RSM however, is possible at zero reference current. A novel construction method is used to build two ideal rotor RSMs. Measured flux linkage curve results of the ideal rotor RSMs correlate well with simulation results and it is shown that the electrical angle of the machine can be tracked successfully at zero reference current. The FE simulation package is used to compare the saliency of the RSM on a per-unit scale to three types of field intensified permanent magnet (FI-PM) synchronous machines and a field weakening interior permanent magnet synchronous machine. It is shown that the saliency of the RSM is larger than that of the investigated PM machines from zero up to rated load. It is thus concluded that the RSM is well suited to saliency-based PSC (SB-PSC) methods, which are used to control synchronous machines at startup and low speeds. The hybrid PSC methods developed in this thesis, are tested and evaluated on three proposed industry applications. The first is a reluctance synchronous wind generator with an inverter output LC filter. The LC filter allows long cables to be used and reduces the voltage stress on the stator windings of the machine. The combination of the LC filter and hybrid PSC method allows the power electronics and controller to be stationed in the base of the turbine tower. A new stator quantity estimation method is derived to omit the need of current and voltage sensors on the machine side of the LC filter. Good maximum power point tracking laboratory results are shown with the high frequency injection-assisted hybrid PSC method. The second application investigated is a position sensorless controlled variable gear electric vehicle (EV) RSM drive. Simulation and measured results show good torque capabilities of the position sensorless controlled EV RSM. It is shown through simulation results that the fundamental current harmonic is dominant in the demodulation scheme of the high frequency injection position sensorless control (HFIPSC) method due to the high current rating of the proposed RSM. The HFI-PSC method is extended to reduce the effect of the fundamental current harmonic in the demodulation scheme without adding any additional filters. The final investigated application is a novel mine scraper winch, which uses two position sensorless controlled RSMs to retrieve ore from the blast site underground. The new design improves on the safety, efficiency and durability of the current scraper winch design. Measured results show that the position sensorless controlled winch RSM is able to deliver rated startup torque with both investigated SB-PSC methods. Finally an automation method is implemented and tested to limited the applied force on the scraper and automatically free itself when stuck. / AFRIKAANSE OPSOMMING: Die posisie sensorlose beheer eienskappe van die reluktansie sinchroonmasjien (RSM) word in hierdie tesis ondersoek met die fokus op industriële toepassings waar varierende dinamiese draaimoment vereis word vanaf stilstand tot by ken spoed. Twee lae spoed- en een ho¨e spoed posisie sensorlose beheer (PSB) metodes vir RSMe is ondersoek. Hierdie metodes is uitgebrei om twee hibriede PSB metodes to skep wat die RSM van stilstand tot by kenspoed posisie sensorloos kan beheer. Die ontwikkelde hibriede metodes maak gebruik van ’n histerese oorskakelings skema en fase geslote lus sinchronisasie Daar word in hierdie tesis bevestig dat die laterale rib RSM nie beheer kan word met die geondersoekte PSB metodes by nul stroom nie. Eindige element simulasie resultate wys egter daarop dat die ideale rotor RSM wel beheer kan word met die geondersoekte metodes by nul stroom. ’n Nuwe konstruksie metode is voorgestel om twee ideale rotor RSMe to bou. Gemete vloed omsluiting kurwes resultate korreleer baie goed met dié van die eindige element simulasies. Gemete resultate wys ook daarop dat PSB van die nuwe masjiene moontlik is by nul stroom. ’n Eindige element pakket is gebruik om die speek-koëffissiënt van die RSM te vergelyk met drie tipes veld-versterkte permanent magneet masjiene, asook een veld verswakte permanent magneet versinkte masjien. Die simulasie resultate wys dat die RSM se speek-koëffissiënt hoër is as die van die geondersoekte permanent magneet masjiene. Die RSM is dus geskik vir speek-koëffissiënt georienteerde PSB metodes, wat hoofsaaklik by stilstand en lae spoed gebruik word. Die ontwikkelde hibried PSB metodes is getoets en geëvalueer met drie voorgestelde industriële toepassings. Die eerste is ’n reluktansie sinchroon wind generator met ’n omsetter uittree laagdeurlaat filter. Die laagdeurlaat filter laat toe dat langer kabels vanaf die omsetter na die generator gebruik kan word. Die kombinasie van die laagdeurlaat filter en die PSB metodes laat toe dat die drywingselektronika en die beheerders in die toring basis geplaas kan word. Dit kan die gewig van die nasel verminder. Goeie maksimum drywingspunt volging laboratorium resultate word getoon met die hoë frekwensie ondersteunde hibried PSB metode. Die tweede geondersoekte toepassing is ’n posisie sensorlose beheerde, varierende ratkas elektriese voertuig RSM. Goeie simulasie en gemete draaimoment resultate van die RSM word getoon. Simulasie resultate toon dat die fundamentele q-as stroom harmoniek dominant is in die demodulasie skema van die hoë frekwensie PSB metode, as gevolg van die hoë ken stroom van die motor. Die hoë frekwensie PSB metode is uitgebrei om die fundamentele stroom harmoniek te onderdruk in die demodulasie skema sonder om enige filters by te voeg. Die finale toepassing is ’n nuwe myn windas wat van twee posisie sensorlose beheerde RSMe gebruik maak om klippe ondergronds te verplaas vanaf die ontploffings area. Die voorgestelde ontwerp verbeter die huidige ontwerp ten opsigte van die veiligheid, energie effektiwiteit en robuustheid. Gemete resultate wys dat ken draaimoment moontlik is met altwee speek-koëffissiënt metodes. ’n Automasie metode, wat die maksimum draaimoment op die windas beperk en automaties homself bevry indien hy vasval, is voorgestel en geëvalueer.
146

Applied Real-Time Integrated Distributed Control Systems: An Industrial Overview and an Implemented Laboratory Case Study

Zaitouni, Wael K 08 1900 (has links)
This thesis dissertation mainly compares and investigates laboratory study of different implementation methodologies of applied control systems and how they can be adopted in industrial, as well as commercial, automation applications. Namely the research paper aims to assess or evaluate eventual feedback control loops' performance and robustness over multiple conventional or state-of-the-art technologies in the field of applied industrial automation and instrumentation by implementing a laboratory case study setup: the ball on beam system. Hence, the paper tries to close the gap between industry and academia by: first, conducting a historical study and background information of main evolutional and technological eras in the field of industrial process control automation and instrumentation. Then, some related basic theoretical as well as practical concepts are reviewed in Chapter 2 of the report before displaying the detailed design. After that, the next Chapter, analyses the ball on beam control system problem as the case studied in the context of this research through reviewing previous literature, modeling and simulation. The following Chapter details the proposed design and implementation of the ball on beam case study as if it is under the introduced distributed industrial automation architecture. Finally, Chapter 5 concludes this work by listing several points leaned, remarks, and observations, and stating possible development and the future vision of this research.
147

Prototipagem virtual: modelagem, simulação, controle e otimização de dinâmica veicular / Virtual prototyping: modelling, simulating, controlling and optimizing vehicle dynamics

Barbieri, Frederico Augusto Alem 22 August 2002 (has links)
As futuras utilizações de sistemas de controle em automóveis seguirão a tendência de integração, através do desenvolvimento de sistemas de controle integrados capazes de coordenar as ações dos vários subsistemas que compõem o veículo. Esta coordenação e integração requerem que as integrações entre os subsistemas sejam levadas em conta já nos primeiros estágios de projeto, levando ao desenvolvimento de modelos completos de veículos. Neste sentido, o comportamento dinâmico de um veículo de quatro rodas é analisado através de técnicas de modelagem de sistemas multicorpos utilizando-se o programa ADAMS. Posteriormente, são gerados modelos lineares obtidos através do Jacobiano das equações do modelo original, resultando em uma gama de equações na forma de espaço de estados. O modelo linearizado é então submetido a vários tipos de simulações e os resultados são comparados às respostas do modelo não linear de modo a validar as aproximações lineares em diferentes condições de operação do veículo. São também desenvolvidos dois sistemas de controle de suspensão baseados em técnicas de controle ótimo como duas diferentes abordagens: um controlador skyhook que foi implementado no modelo não linear desenvolvido no ADAMS e um controle de suspensão baseado em um controlador RLQ (Regulador Linear Quadrático), com realimentação de saída que utiliza os modelos linearizados na forma de espaço de estados, sendo este último implementado através da co-simulação ADAMS/Matlab. O sistema de controle de suspensão desenvolvido é um primeiro passo na tentativa de projeto de um sistema de controle integrado do movimento. / Future applications of control in automotive vehicles will follow a trend towards system integration, leading ultimately to the development of integrated vehicle control systems capable of coordinating the action of the various subsystems. The coordination and integration of automotive vehicle subsystems require the interaction amongst the various subsystems to be taken into consideration at the control design stages, resulting in full vehicle models. Therefore, a nonlinear 10 degree of freedom model is obtained through MBS modelling techniques present in ADAMS package software. Then, a linear model is obtained by linearization of the system equations through the Jacobian facility also present in ADAMS. The resulting linearised models are simulated and their response are compared to the previous non-linear one in order to validate the linear approximations. This work also presents two distincts suspension control systems based in optimal control theory: a skyhook controler designed at ADAMS (with the non-linear vehicle model) and a LQR (Linear Quadratic Regulator) with output feedback based on the state space linear vehicle model. This last one was designed through ADAMS/Matlab co-simulation facilities. This designed suspension control is a first attempt to future developments of integrated vehicle control.
148

Projeto e construção de um motor elétrico linear aplicado à bioengenharia / Design and construction of a linear electric motor applied to bioengineering

Juliani, Aline Durrer Patelli 14 January 2011 (has links)
Considerando-se o atual estagio de desenvolvimento das máquinas elétricas, tanto em termos de ferramentas computacionais auxiliares nas simulações e nos projetos, quanto de materiais e sistemas eletrônicos de acionamento e controle, propõe neste trabalho a construção de um dispositivo eletromecânico, na classe dos motores elétricos lineares, que atenda as necessidades e se aplique a bioengenharia, mais propriamente as próteses de membro superior, na forma de acionador translacional. Este dispositivo deve substituir os sistemas que utilizam motores elétricos rotativos com mecanismos de adaptação mecânica (roldanas, vários fios, redutores), que convertem o movimento rotacional em linear. Também, os dispositivos híbridos, como atuadores eletro-hidráulicos e eletropneumáticos, que necessitam de fontes de energia de naturezas diferentes da eletroeletrônica, podem ser substituídos pelas maquinas elétricas lineares. Uma revisão dos conceitos relacionados a área de bioengenharia e feita, destacando-se os mecanismos de transmissão existentes. E apresentada uma analise comparativa entre os principais motores lineares, enfatizando-se as características construtivas, as vantagens e as desvantagens de cada um, relacionados a aplicação. A escolha da maquina a ser projetada e construída recaiu no motor linear síncrono, com imas permanentes na superfície da parte móvel, em uma estrutura tubular. Para esta maquina, e exposta uma metodologia de projeto, baseando-se nos seguintes tópicos: equacionamento do circuito magnético, cálculos de parâmetros utilizando-se o método dos elementos finitos e modelagem matemática por meio das equações por fase. Apos a etapa teórica, a construção da maquina e apresentada juntamente com os ensaios experimentais, possibilitando a comparação das características reais em relação ao projeto inicial. Por fim, o motor e aplicado ao dedo artificial, verificando-se a sua capacidade de substituição do motor rotativo. / By means of the latest technological advances of the electrical machines, both in terms of computational aids in simulations and designs, materials and electronic systems of drive and control, this work put forward the construction of an electromechanical device, in the class of the linear motors. It will be applied to bioengineering area, in particular in upper limb prostheses, in the form of a translational actuator. This linear motor must substitute the systems that use electric rotational motors with planetary gears and lead screw transmission, to convert the rotational movement into linear. The hybrid mechanisms, like electro pneumatic/hydraulic actuators, which need energy sources different from electronics, can be changed for the linear electric machines too. A review about bioengineering topics is done, where the existent mechanical mechanisms are highlighted. According to the application necessities, the advantages and disadvantages of different topologies of electric linear machines are compared and the constructive characteristics are emphasized. The tubular linear synchronous motor, with permanent magnets on the surface of the mobile part, was chosen to be applied to hand prostheses. To this machine, a design methodology is presented for calculating the motor dimensions, based on the following subjects: magnetic circuit equating, finite element analyses to evaluate parameters and machine dynamic modeling. After the theorethical stage, the construction of the machine is presented with the experimental results, allowing comparisons between the real characteristics and the initial design features of the motor. Finally, the machine is applied to an artificial finger to verify its capability to replace the rotational motor.
149

Projeto e construção de um motor elétrico linear aplicado à bioengenharia / Design and construction of a linear electric motor applied to bioengineering

Aline Durrer Patelli Juliani 14 January 2011 (has links)
Considerando-se o atual estagio de desenvolvimento das máquinas elétricas, tanto em termos de ferramentas computacionais auxiliares nas simulações e nos projetos, quanto de materiais e sistemas eletrônicos de acionamento e controle, propõe neste trabalho a construção de um dispositivo eletromecânico, na classe dos motores elétricos lineares, que atenda as necessidades e se aplique a bioengenharia, mais propriamente as próteses de membro superior, na forma de acionador translacional. Este dispositivo deve substituir os sistemas que utilizam motores elétricos rotativos com mecanismos de adaptação mecânica (roldanas, vários fios, redutores), que convertem o movimento rotacional em linear. Também, os dispositivos híbridos, como atuadores eletro-hidráulicos e eletropneumáticos, que necessitam de fontes de energia de naturezas diferentes da eletroeletrônica, podem ser substituídos pelas maquinas elétricas lineares. Uma revisão dos conceitos relacionados a área de bioengenharia e feita, destacando-se os mecanismos de transmissão existentes. E apresentada uma analise comparativa entre os principais motores lineares, enfatizando-se as características construtivas, as vantagens e as desvantagens de cada um, relacionados a aplicação. A escolha da maquina a ser projetada e construída recaiu no motor linear síncrono, com imas permanentes na superfície da parte móvel, em uma estrutura tubular. Para esta maquina, e exposta uma metodologia de projeto, baseando-se nos seguintes tópicos: equacionamento do circuito magnético, cálculos de parâmetros utilizando-se o método dos elementos finitos e modelagem matemática por meio das equações por fase. Apos a etapa teórica, a construção da maquina e apresentada juntamente com os ensaios experimentais, possibilitando a comparação das características reais em relação ao projeto inicial. Por fim, o motor e aplicado ao dedo artificial, verificando-se a sua capacidade de substituição do motor rotativo. / By means of the latest technological advances of the electrical machines, both in terms of computational aids in simulations and designs, materials and electronic systems of drive and control, this work put forward the construction of an electromechanical device, in the class of the linear motors. It will be applied to bioengineering area, in particular in upper limb prostheses, in the form of a translational actuator. This linear motor must substitute the systems that use electric rotational motors with planetary gears and lead screw transmission, to convert the rotational movement into linear. The hybrid mechanisms, like electro pneumatic/hydraulic actuators, which need energy sources different from electronics, can be changed for the linear electric machines too. A review about bioengineering topics is done, where the existent mechanical mechanisms are highlighted. According to the application necessities, the advantages and disadvantages of different topologies of electric linear machines are compared and the constructive characteristics are emphasized. The tubular linear synchronous motor, with permanent magnets on the surface of the mobile part, was chosen to be applied to hand prostheses. To this machine, a design methodology is presented for calculating the motor dimensions, based on the following subjects: magnetic circuit equating, finite element analyses to evaluate parameters and machine dynamic modeling. After the theorethical stage, the construction of the machine is presented with the experimental results, allowing comparisons between the real characteristics and the initial design features of the motor. Finally, the machine is applied to an artificial finger to verify its capability to replace the rotational motor.
150

Prototipagem virtual: modelagem, simulação, controle e otimização de dinâmica veicular / Virtual prototyping: modelling, simulating, controlling and optimizing vehicle dynamics

Frederico Augusto Alem Barbieri 22 August 2002 (has links)
As futuras utilizações de sistemas de controle em automóveis seguirão a tendência de integração, através do desenvolvimento de sistemas de controle integrados capazes de coordenar as ações dos vários subsistemas que compõem o veículo. Esta coordenação e integração requerem que as integrações entre os subsistemas sejam levadas em conta já nos primeiros estágios de projeto, levando ao desenvolvimento de modelos completos de veículos. Neste sentido, o comportamento dinâmico de um veículo de quatro rodas é analisado através de técnicas de modelagem de sistemas multicorpos utilizando-se o programa ADAMS. Posteriormente, são gerados modelos lineares obtidos através do Jacobiano das equações do modelo original, resultando em uma gama de equações na forma de espaço de estados. O modelo linearizado é então submetido a vários tipos de simulações e os resultados são comparados às respostas do modelo não linear de modo a validar as aproximações lineares em diferentes condições de operação do veículo. São também desenvolvidos dois sistemas de controle de suspensão baseados em técnicas de controle ótimo como duas diferentes abordagens: um controlador skyhook que foi implementado no modelo não linear desenvolvido no ADAMS e um controle de suspensão baseado em um controlador RLQ (Regulador Linear Quadrático), com realimentação de saída que utiliza os modelos linearizados na forma de espaço de estados, sendo este último implementado através da co-simulação ADAMS/Matlab. O sistema de controle de suspensão desenvolvido é um primeiro passo na tentativa de projeto de um sistema de controle integrado do movimento. / Future applications of control in automotive vehicles will follow a trend towards system integration, leading ultimately to the development of integrated vehicle control systems capable of coordinating the action of the various subsystems. The coordination and integration of automotive vehicle subsystems require the interaction amongst the various subsystems to be taken into consideration at the control design stages, resulting in full vehicle models. Therefore, a nonlinear 10 degree of freedom model is obtained through MBS modelling techniques present in ADAMS package software. Then, a linear model is obtained by linearization of the system equations through the Jacobian facility also present in ADAMS. The resulting linearised models are simulated and their response are compared to the previous non-linear one in order to validate the linear approximations. This work also presents two distincts suspension control systems based in optimal control theory: a skyhook controler designed at ADAMS (with the non-linear vehicle model) and a LQR (Linear Quadratic Regulator) with output feedback based on the state space linear vehicle model. This last one was designed through ADAMS/Matlab co-simulation facilities. This designed suspension control is a first attempt to future developments of integrated vehicle control.

Page generated in 0.1021 seconds