• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 67
  • 42
  • 31
  • 17
  • 7
  • 6
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 201
  • 96
  • 43
  • 38
  • 28
  • 26
  • 24
  • 24
  • 21
  • 17
  • 16
  • 16
  • 15
  • 15
  • 15
  • 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.
51

A Dirigible Bowling Ball : Controlling a bowling ball to hit a strike every time / Ett styrbart bowlingklot

Fröberg, Joel, Smolic, Magdalena January 2021 (has links)
The purpose of this bachelor’s thesis is to investigate the uses of spherical robots and on a prototype basis construct and control a dirigible bowling ball. The robot is able to steer left and right after being thrown by the user. This occurs due to a weight displacement inside the ball when a weighted pendulum swings left and right by being radio controlled from afar. The goal of the report is to investigate how well this robot will be able to steer and if it can achievea desired strike. Further, this report will investigate the use of Radio Frequency (RF) signals between a hand controller and the ball and at what distance this method will work. This robot is strictly made for scientific purposes, the authors do not advocate cheating in the sport of bowling in any way. / Syftet med denna kandidatuppsats är att undersöka användningen av sfäriska robotar och på en prototypbasis konstruera och styra ett styrbart bowlingklot. Roboten kommer att kunna styras åt vänster och höger efter att ha kastats avanvändaren. Detta inträffar på grund av en viktförskjutning inuti klotet då en viktad pendel svänger åt vänster och åt höger genom att radiostyras på håll. Målet med rapporten är att undersöka hur bra den här roboten kommer att kunna kontrolleras och om en strike kan uppnås med den nya och samlade kunskapen. Vidare kommer användningen av Radio frekventa (RF)-signaler mellan en handkontroll och klotet att undersökas, hur väl detta kan implementeras och även på hur långt avstånd denna metod kan fungera. Denna robot är endast gjord för vetenskapliga ändamål, författarna förespråkar inte fusk i sporten bowling på något sätt.
52

Controlador de posição linear hidro-pneumático. / Hydro pneumatic linear position controller.

Jesus, Sidney Nogueira Pereira de 27 March 2008 (has links)
Nessa pesquisa é apresentada uma inovação tecnológica em aplicações de controle de posição em máquinas e/ou dispositivos: o Controlador de Posição Linear Hidro- Pneumático. Para os casos nos quais têm-se grandes esforços combinados com pequenos deslocamentos, normalmente esse trabalho é feito com o uso de Sistemas Servo-Hidráulcos nos quais, devido às características mencionadas do nicho de mercado visado pela presente proposta, representam um custo elevado quando comparado com a solução Hidro-Pneumática aqui descrita. Salienta-se a simplicidade da infra-estrutura requerida para a instalação dessa alternativa, e também a redução do desperdício energético com relação à tecnologia tradicional com a Servo-Hidráulica. Observou-se nos testes com o protótipo, um excelente desempenho do sistema em termos de rapidez de resposta, como ainda no quesito resolução de posicionamento cujos valores encontrados apresentam-se na casa de 0,05 segundos e 0,01 mm, respectivamente. O pequeno tamanho físico obtido com essa nova tecnologia é outro item relevante, permitindo-se o seu emprego em locais de reduzido espaço disponível. . Resultados de simulações numéricas e de testes experimentais são apresentadas, bem como perspectivas de desenvolvimentos futuros. / This research presents a technological innovation for applications in machine / device position control: the Hydro-Pneumatic Linear Position controller. In cases where great efforts are combined with small dislocations, this task is normally accomplished by means of Servo Hydraulic Systems that, due to particular characteristics of the market envisaged by the present proposition, represent elevated costs, when compared to those of the hydro-pneumatic solution described here. This work presents an analytical numerical model for the devise as well as an experimental prototype. It worth noting the infra-structure simplicity required for this alternative implementation, and also the reduction in energy waste when compared to the traditional servo-hydraulic technology. The prototype experimental tests demonstrated the system excellent behavior in what concerns answer speed and position resolution whose values were respectively in range 0.05 s and 0,01 mm. The small physical size obtained with this technology is another relevant item, which allows the device use in places of reduced available space. Numerical simulation and experimental test results are presented as well as perspectives of future developments
53

Integrated Design of Servo Mechatronic Systems for Driving Performance Improvement

Chen, Chin-yin 05 February 2009 (has links)
The servo mechatronic system design process usually covers two different engineering domains: structure design and system control. The relationship between these two domains is much closed. In order to reduce the disturbance caused by parameters in either one, the domain knowledge from those two different fields needs to be integrated. Thus, in order to reduce the disturbance caused by parameters in either one, the mechanical and controller design domains need to be integrated. Therefore, the integrated design method Design For Control (DFC), will be employed in this thesis. In this connect, it is not only applied to achieve minimal power consumption but also enhance structural performance and system response at same time. To investigate for the integrated design method, there are two common servo mechatronic systems: feed drive system and legged servo mechatronic system are used as the design platform. 1. Mechatronic Feed Drive System To investigate the method for integrated optimization, a mechatronic feed drive system of the machine tools is used as a design platform. The 3D software, Pro/Engineer is first used to build the 3D model to analyze and design structure parameters such as elastic deformation, nature frequency and component size, based on their effects and sensitivities to the structure. Additionally, in order to achieve system robust, Quantitative Feedback Theory (QFT), will be applied to determine proper control parameters for the controller. Therefore, overall physical properties of the machine tool will be obtained in the initial stage. Following this Design Then Control process, the iterative design process is following to enhance some of system performance. Finally, the technology design for control will be carried out to modify the structural and control parameters to achieve overall system performance. Hence, the corresponding productivity is expected to be greatly improved. 2. Legged Servo Mechatronic System The goal of this study is to develop a one-degree-of-freedom (DOF) legged servo mechatronic system with DFC. For this system, the kinematics and control dynamic analysis of legged servo mechatronic system have been solved by using four bar linkage with symmetrical coupler point, pantograph, and common position and velocity controller. In addition, in order to improvement system dynamic performance and reduce the control cost, the counterweight, that base on mass redistribution is employed to integrate structure and control into one design step for reduce shaking moment. Additionally, in order to improvement the system performance, the complete force balance is not only to take advantage of control cost, but also easy to control.
54

Visual servo control for a human-following robot

Burke, Michael Glen 03 1900 (has links)
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.
55

Force equalization for active/active redundant actuation system involving servo-hydraulic and electro-mechanical technologies / Stratégie d'égalisation d'effort dans les systèmes d'actionnement actif-actif impliquant les technologies servo-hydraulique et électro-mécanique

Wang, Lijian 18 December 2012 (has links)
L'évolution vers les avions plus électriques engendre des efforts importants pour développer des actionneurs à source de puissance électrique pour les commandes de vol. Pour de telles applications critiques, il est peut être intéressant dans le futur d'associer à une même surface de contrôle un actionneur conventionnel à source de puissance hydraulique et un actionneur à source de puissance électrique mais ceci pose un problème important lorsque les deux actionneurs sont actifs simultanément: comme chacun essaye d'imposer sa position à l'autre,les deux actionneurs luttent l'un contre l'autre en développant des efforts néfastes qui ne sont pas utilisés par la charge. L'objet du présent travail est de proposer des stratégies d’égalisation d’effort pour un système d'actionnement impliquant ces deux types d''actionneurs opérant en mode actif-actif. La première étape est de concevoir leur commande en position et de la valider sur banc d'essai. Un banc d'essai virtuel fidèle à la réalité est ensuite réalisé dans l'environnement de simulation AMESim pour pouvoir évaluer facilement les différentes stratégies d'égalisation d'effort entre les deux actionneurs. Ces stratégies sont proposées et évaluées virtuellement en deux étapes, statique puis dynamique. Pour finir, une étude de robustesse est réalisée a posteriori pour évaluer la sensibilité des indicateurs de performance aux incertitudes sur les modèles de simulation et sur les points et les conditions de fonctionnement. / On the way to more electric aircraft (MEA), more and more power-by-wire (PBW) actuators are involved in the flight control system. For a hybrid redundant actuation system composed by the conventional hydraulically powered actuators and the PBW actuators, one major issue while they operate on active/active mode is the force fighting between channels. As the grave influence of force fighting on accelerating material fatigue and increasing power consumption,it must be addressed with attention. This thesis was aiming at proposing some effective force equalization control strategies for the hybrid actuation system involving one servo-hydraulic actuator (SHA) and one electro-mechanical actuator (EMA). For this objective, the position controllers for SHA and EMA were designed and validated as a first step. Then, a virtual test bench regarding to the realistic behaviors was built in the AMESim simulation environment to accelerate the controller design and enable the robustness study. Following this, 2 static force equalization control strategies were proposed and experimentally validated. The first strategy hat introduced integral force fighting signal to compensate the actuator position control was proved a good candidate solution. In the next part, 3 dynamic force equalization strategies were proposed and assessed on the virtual test bench. Their performance sensitivities to the parameter uncertainties were studied through Monte-Carlo method. The first strategy that introduced velocity and acceleration feed-forwards to force the SHA and EMA having similar pursuit dynamics showed a good force equalization performance as well as good segregation and good robustness. In the end, the work presented in thesis was concluded and perspective was given to the ongoing work.
56

Controlador de posição linear hidro-pneumático. / Hydro pneumatic linear position controller.

Sidney Nogueira Pereira de Jesus 27 March 2008 (has links)
Nessa pesquisa é apresentada uma inovação tecnológica em aplicações de controle de posição em máquinas e/ou dispositivos: o Controlador de Posição Linear Hidro- Pneumático. Para os casos nos quais têm-se grandes esforços combinados com pequenos deslocamentos, normalmente esse trabalho é feito com o uso de Sistemas Servo-Hidráulcos nos quais, devido às características mencionadas do nicho de mercado visado pela presente proposta, representam um custo elevado quando comparado com a solução Hidro-Pneumática aqui descrita. Salienta-se a simplicidade da infra-estrutura requerida para a instalação dessa alternativa, e também a redução do desperdício energético com relação à tecnologia tradicional com a Servo-Hidráulica. Observou-se nos testes com o protótipo, um excelente desempenho do sistema em termos de rapidez de resposta, como ainda no quesito resolução de posicionamento cujos valores encontrados apresentam-se na casa de 0,05 segundos e 0,01 mm, respectivamente. O pequeno tamanho físico obtido com essa nova tecnologia é outro item relevante, permitindo-se o seu emprego em locais de reduzido espaço disponível. . Resultados de simulações numéricas e de testes experimentais são apresentadas, bem como perspectivas de desenvolvimentos futuros. / This research presents a technological innovation for applications in machine / device position control: the Hydro-Pneumatic Linear Position controller. In cases where great efforts are combined with small dislocations, this task is normally accomplished by means of Servo Hydraulic Systems that, due to particular characteristics of the market envisaged by the present proposition, represent elevated costs, when compared to those of the hydro-pneumatic solution described here. This work presents an analytical numerical model for the devise as well as an experimental prototype. It worth noting the infra-structure simplicity required for this alternative implementation, and also the reduction in energy waste when compared to the traditional servo-hydraulic technology. The prototype experimental tests demonstrated the system excellent behavior in what concerns answer speed and position resolution whose values were respectively in range 0.05 s and 0,01 mm. The small physical size obtained with this technology is another relevant item, which allows the device use in places of reduced available space. Numerical simulation and experimental test results are presented as well as perspectives of future developments
57

Construction and theoretical study of a ball balancing platform : Limitations when stabilizing dynamic systems through implementation of automatic control theory / Konstruktion och teoretisk studie av bollbalanserande plattform

Hasp Frank, Alexander, Tjernström, Morgan January 2019 (has links)
Control theory and its applications are crucial when operating within the area of dynamic systems. Compensating for disturbances and external actions imposed on a given system being inherently unstable or semi-stable. Through the physical construction of a apparatus as a demonstrator of the theory further comparing the factual physical and computer simulated results derived from Newtonian mechanics. To enable comparison, designing a satisfactory controller capable of fulfilling the requirements set for the system is necessary. With regards to apparatus and control, the introduction of a proportional-integralderivative controller for a system balancing a ball on a platform. Further allowing for analysis to determine the limitations when stabilizing a naturally unstable or semi-stable system. Also, examine how these dier from the theoretical expectations. The control applied throughout the thesis is of the type linear, exclusively being able to operate properly within the linear spectrum of control. Using standard components and a microcontroller, a apparatus is constructed to maintain a ball on a platform. This is executed through programming with Arduino libraries and open source code. Hence, for research purposes, to see if the apparatus can operate satisfactory within the linear domain of control. With the aforementioned stated, this thesis will first cover the theoretical model of the ball on platform scenario through computer aided programs. Then compare the theoretical results with the results acquired from a physical construction. Further examine why dierences occur considering control theory and system implementation. / Reglertekniken och dess applikationer är centrala för att kontrollera dynamiska system och möjliggör för kompensering av störningar i system som är naturligt instabila eller semistabila. Genom konstruktion av en apparat som demonstrerar reglerteknisk teori kan vidare jämförelser mellan resultat från apparaten och datorsimuleringar, erhållna från Newtonsk mekanik, tillhandahållas. Syftet är vidare att utveckla en regulator som uppfyller de krav som sätts upp för systemet. Med hänsyn till apparaten och regulatorn, introduceras en proportionell-integrerande-deriverande regulator för en bollbalanserande plattform. På så sätt kan begränsningarna vid stabilisering av ett naturligt instabilt eller semistabilt system bestämmas. Vidare studeras hur dessa skiljer sig från de teoretiska förväntningarna. Endast linjär kontroll kommer att användas i detta projekt, därav en apparat som enbart är välfungerande inom ett linjärt domän. Genom användning av standardkomponenter och en mikrokontroll konstrueras en apparat för att bibehålla en boll på en plattform. Detta möjliggörs genom programmering med Arduinos bibliotek och öppen källkod. Således är, ur forskningssynpunkt, anordningens förmåga att fungera väl inom den linjära domänen av intresse. Utifrån detta kommer examensarbetet först att redogöra för den teoretiska modellen av en boll balanserande på en plattform genom användandet av datorprogram. För att sedan jämföra de teoretiska resultaten med de resultat som erhålls från den fysiska bollbalanserande konstruktionen. Vidare undersöks varför skillnader uppstår med hänsyn till reglerteknik och systemimplementering
58

Comparative Study of Genetic Algorithm Optimized FO-PID and LQR Control Strategies Applied to a Piston Pump in a Volume Calibration System / Jämförande studie av genetisk algoritmoptimerade FOPID och LQR kontrollstrategier tillämpade på en kolvpump i ett volymkalibreringssystem

Deif, Yaman January 2023 (has links)
One of the key responsibilities of Getinge's ventilators is to deliver accurate gas volumes to patients. To ensure this precision, specially designed rigid steel tanks are utilized to evaluate the performance and precision of the ventilators in providing exact air volume. The intention of this study is to design and implement a suitable controller for actuating a servo piston pump in order to be used for the tank volume measuring and calibration process. Two controlling strategies were chosen for this purpose: Linear Quadratic Regulator (LQR) and Fractional Order Proportional Integral Derivative (FOPID). This work also aimed to establish a narrative of the two controlling strategies after optimizing them using genetic algorithm optimization (GA) and evaluating their effectiveness in controlling a brushless DC motor (BLDC) actuating a servo piston pump. This involved modeling the system in Matlab and Simulink based on the mathematical representations of the system's dynamics, specifically focusing on its pneumatic behavior. The nonlinear model was linearized and served as a basis for the controllers' optimization through the genetic algorithm. Both controller designs were then compared in both the Simulink environment and the actual physical system. The results show that the FOPID exhibits superior performance in the Simulink environment. Contrariwise, the LQR displays a far greater level of superiority in the physical system, whereas the FOPID performance significantly deteriorated upon implementation in the physical system. Furthermore, the study suggests implementing anti-windup techniques and ensuring the accurate digitization of fractional calculus for further research to enhance the performance of the FOPID controller on the physical system. / En av de centrala uppgifterna för Getinges ventilatorer är att leverera exakta gasvolymer till patienter. För att säkerställa denna precision används speciellt designade ståltankar för att bedöma ventilatorernas funktion och precision att leverera exakt luftvolym. Syftet med denna studie är att utforma och implementera en lämplig Styrenhet för att aktivera en servokolvspump som ska användas för tankvolymens mätning och kalibreringsprocess. Två styrstrategier valdes för detta ändamål: Linear Quadratic Regulator (LQR) och Fractional Order Proportional Integral Derivative (FOPID). Arbetet kommer också att syfta till att etablera ett narrativ för de två styrstrategierna efter att ha optimerat dem med genetisk algoritmoptimering (GA) och utvärderat deras effektivitet vid styrning av en borstlös DC-motor som aktiverar en servokolvspump. Detta innefattade modellering av systemet i Matlab och Simulink baserat på de matematiska representationerna av systemdynamiken, med speciellt fokus på dess pneumatiska beteende. Den icke-linjära modellen linjäriserades och fungerade som grund för regulatorernas optimering genom den genetiska algoritmen (GA). Båda regulatorernas utformningar jämfördes sedan både i Simulink-miljön och det fysiska systemet. Resultaten visar att FOPID uppvisar överlägsen prestanda i Simulink-miljön. Å andra sidan visar sig LQR vara överlägsen i det fysiska systemet, medan FOPID-prestandan försämras avsevärt vid implementering i det fysiska systemet. Dessutom föreslår studien att implementera anti-windup-tekniker och säkerställa korrekt digitalisering av fraktionell kalkyl för vidare forskning för att förbättra prestanda för FOPID-regulatorn på det fysiska systemet.
59

Dynamical Adaptive Backstepping-Sliding Mode Control for servo-pneumatic positioning applications: controller design and experimental evaluation

Abd. Rahman, Ramhuzaini 24 February 2016 (has links)
Servo control of pneumatic actuators is difficult due to the high compressibility and non-linear flow of air. Friction as well as uncertainties in the parameters and model character-izing dynamics of the pneumatic systems further contribute to control challenges. These drawbacks cause stick-slip motion, larger tracking error and limit cycles, which degrades the control performances. Selection of a controller that satisfies requirements of the per-forming tasks is thus crucial in servo-pneumatic applications. This thesis focuses on the design and experimental evaluation of a model-based, nonlinear controller known as Dy-namical Adaptive Backstepping-Sliding Mode Control (DAB-SMC). Originally designed for chemical process control and applied only in simulations, the DAB-SMC is adopted in this thesis and applied to the new area of servo-pneumatic control of a single-rod, double acting pneumatic cylinder and antagonistic pneumatic artificial muscles (PAMs). The con-troller is further enhanced by augmenting it with LuGre-based friction observers to com-pensate the adverse frictional effect presents in both actuators. Unlike other research works, the actuators are subject to a varying load that influences control operations in two different modes: motion assisting or resisting. The implementation of DAB-SMC for such servo-pneumatic control application is novel. The mass flow rates of compressed air into and out of the actuators are regulated using one of the following valve configurations: a 5/3-way proportional directional valve, two 3/2-way or four 2/2-way Pulse Width Modu-lation (PWM)-controlled valves. Over the entire range of experiments which involve vari-ous operating conditions, the DAB-SMC is observed to track and regulate the reference input trajectories successfully and in a stable manner. Average root mean square error (RMSE) values of tracking for cylinder and PAMs when the compressed air is regulated using the 5/3-way proportional valve are 1.73mm and 0.10°, respectively. In case of regu-lation, the average steady-state error (SSE) values are 0.71mm and 0.04°, respectively. The DAB-SMC exhibits better control performance than the standard PID and classical SMC by at least 33%. The DAB-SMC also demonstrates robustness for up to 78% in un-certainty of load parameter. When the control valve is replaced by the PWM-controlled valves of 3/2-way and 2/2-way configurations, performance is slightly compromised. / May 2016
60

A MORE EFFICIENT TRACKING SYSTEM FOR THE SANTIAGO SATELLITE TRACKING STATION

Ramírez, Eduardo Díaz 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / A digital antenna control system has been designed and installed on a pedestal that was formerly used to drive a VHF array and that has now been replaced with an 11 meter S-Band parabolic reflector. In this Paper, the former analog tracking system will be described, showing all the drawbacks that made it unusable for S-Band. Subsequently, the development and implementation of the digital S-Band tracking system, using Labview, C++ & digital control theory will be discussed. Finally, there will be a comparison between the digital and analog system, too.

Page generated in 0.0289 seconds