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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.
51

Effets des équipements de fantassin modernes sur la locomotion et la fatigue neuromusculaire du soldat déployé : simulation opérationnelle / Effects of modern land warfare equipments on deployed soldier locomotion and neuromuscular fatigue : operational simulation

Grenier, Jordane 15 November 2012 (has links)
La problématique du port de charges par l’Homme est l’objet de questionnements scientifiques depuis plus d’un siècle, notamment dans les armées où les soldats doivent remplir des objectifs opérationnels tout en emportant des équipements lourds, distribués de façon complexe autour de leur corps, et cela au cours d’efforts allant de quelques heures à plusieurs jours. Aussi, avec le développement des nouvelles technologies et l’arrivée des systèmes fantassins futurs sur le marché de la défense, cette problématique continue de se complexifier puisque la masse totale emportée tend encore à croître. Objectif général : Le but de ce travail de thèse était d’étudier l’impact biomécanique, métabolique et neuromusculaire du port d’un système fantassin moderne chez le soldat expérimenté. Plus précisément, une première recherche a été menée pour caractériser les effets aigus du port d’un tel équipement sur la biomécanique et le coût métabolique de la marche. Puis, une seconde recherche a été consacrée à l’étude des conséquences neuromusculaires et locomotrices d’une mission militaire (simulation sur le terrain) de durée « extrême » réalisée avec ce système fantassin moderne. Première partie : L’analyse de la marche sur tapis roulant dynamométrique a permis de montrer que le port du système fantassin en configurations de « combat » et de « marche d’approche » (principales configurations du théâtre militaire, représentant respectivement ~30 % et ~50 % de la masse corporelle des sujets) altérait le pattern spatio-temporel par rapport à la marche sans charge. Par ailleurs, le travail mécanique appliqué au centre de masse et le coût métabolique de la marche augmentaient parallèlement lors du port des deux configurations du système fantassin, ce qui résultait en un maintien du rendement locomoteur constant dans toutes les conditions testées. Le mécanisme de transfert d’énergie en pendule inversé (méthode Cavagna), permettant de minimiser les coûts mécanique et métabolique de transport, était également similaire dans toutes les conditions avec et sans charge. Enfin, bien que complexement organisés autour du corps du soldat, les équipements militaires n’induisaient pas d’effets mécaniques et métaboliques sensiblement plus importants que ceux rapportés lors du port de masses positionnées symétriquement autour de la taille ; ce mode de portage étant pourtant considéré comme l’un des plus optimisés, abstraction faite des techniques de portage sur la tête inadaptées au contexte militaire. Deuxième partie : La réalisation d’une mission simulée, incluant 21 h d’activités militaires sur le terrain et le port constant d’un système fantassin, résultait en une fatigue neuromusculaire (mesure des forces, électrostimulation et EMG) relativement modérée des muscles locomoteurs extenseurs du genou et fléchisseurs plantaires chez les soldats expérimentés inclus dans ce travail. Les origines de cette fatigue neuromusculaire étaient essentiellement périphériques, mais s’accompagnaient d’une fatigue subjective importante. Enfin, la réalisation de la mission, et donc la fatigue des muscles locomoteurs notamment associée à cette dernière, n’affectait pas sensiblement les paramètres mécaniques et métaboliques de la marche. Conclusion générale : Ce travail rapporte les premières données relatives aux effets biomécaniques, métaboliques et neuromusculaires du port d’un système fantassin moderne chez le soldat expérimenté, et ce par le biais d’une simulation opérationnelle visant à reproduire les conditions militaires / For more than a century, load carriage has been the source of many scientific questions and researches, especially in armies in which soldiers have to reach operational goals while carrying heavy loads complexly distributed around their body and this for some hours to several days. Moreover, with the development of new technologies and the advent of land warfare systems, this issue is becoming more complex since load continues to increase. General purpose: The aim of the present work was to investigate the biomechanical, metabolic and neuromuscular constraints imposed by the carriage of a modern land warfare system in experienced soldiers. Specifically, a first study was conducted to characterize the acute effects of land warfare equipments carriage on the biomechanics and energetics of walking. Moreover, a second research was performed to investigate the neuromuscular and locomotor consequences of an extreme-duration simulated military mission (performed in the field) involving the carriage of these specific equipments. First part: Walking analyses performed on an instrumented treadmill showed that the carriage of a land warfare system in two configurations made for “Battles” and “Road marches” (main configuration used in the field representing ~30% and ~50% of subject’s body mass, respectively) altered the walking pattern. Moreover, the mechanical work applied to the center of mass increased in parallel with the energy cost of walking during Battle and Road March configurations carriage, as shown by the constant locomotor efficiency in the three tested conditions. The inverted pendulum-like energy exchange (Cavagna’s standard method), allowing mechanical/metabolic energy saving, was also constant in all the unloaded and loaded conditions. Finally, even if the load was complexly distributed around soldiers’ body with this warfare system, this did not induce greater effects than those reported with loads carried symmetrically around the waist and close to the center of mass; which has yet been hypothesized to be the optimal method of load carriage from both mechanical and metabolic standpoints (except “original” methods such as head carrying that cannot be used in the military theater). Second part: Performing a 21-h simulated military mission with heavy land warfare system carriage induced relatively moderate neuromuscular alterations (isometric force measurement with electrical stimulation and EMG) for both knee extensors and plantar flexors locomotor muscle groups in experienced soldiers. Moreover, the origin of fatigue was essentially peripheral for both muscle groups but was concomitant with a large sensation of fatigue. Finally, the simulated mission, and notably the associated locomotor muscles fatigue, did not alter walking biomechanics and energetics. General conclusion: These results bring the first insight into the biomechanical, metabolic and neuromuscular consequences of modern land warfare system carriage in experienced soldiers, and this by a real-world approach aiming at simulating the military theater conditions
52

Realisierung einer prototypischen Hardwarelösung für ein inverses Pendel / FPGA-only Based Closed-loop Control for a Very Compact Inverted Pendulum with Kalman Filter

Berger, Benjamin 17 February 2011 (has links) (PDF)
Ziel der Arbeit ist die anschauliche Demonstration der Leistungsfähigkeit von Hardware- Systemen zur Regelung instabiler Systeme am Beispiel des Inversen Pendels. Dabei handelt es sich um das Balancieren eines Stabes, einem Standard-Problem der Regelungstechnik. Es wird die Konzeption und Implementierung einer Hardware-Regelung in einem FPGA-Prototypenboard zur Realisierung dieser Aufgabe beschrieben. Die Regelung basiert mit LQR-Entwurf und Kalman-Filter auf klassischen Methoden der Regelungstechnik. Zur Demonstration der Regelung wurde ein mechanischer Aufbau vorgenommen, an dem die Funktionsfähigkeit des Inversen Pendels praktisch gezeigt wurde.
53

Investigations on Dynamics and Control of a Rimless Wheel Based 2D Dynamics Walker using Pulsed Torque Actuation

Patnaik, Lalit January 2014 (has links) (PDF)
Wheeled systems are energy efficient on prepared surfaces like roads and tracks. Legged systems are capable of traversing different terrains but can be lossy. At low speeds and on off-road surfaces, legged systems using dynamic walking can be energy efficient. Towards this objective, the dynamics of the walker needs to be modelled and controlled. In addition, the braking and ground impact losses need to be minimized. This thesis presents analysis and experiments on the dynamics and control of a rimless-spoked-wheel based mobile robot (Chatur ∗) that belongs to a category between wheeled and legged systems. This rolling rimless wheel is effectively a 2D dynamic walker that serves as a platform for investigating the dynamics and energetics of inverted pendulum walking with constant step angle. A pulsed actuation torque is proposed for the system resulting in four torque regimes defined by the ratio of energy losses to available actuator torque. Five physical constraints that impose fundamental limits on the choice of operating points of a generic inverted pendulum walker are expounded and a method for locating optimal operating points is discussed. Chatur’s hardware design is elaborated and a control topology is proposed for pulsed actuation of the dual brushless dc (BLDC) motor driven platform with wheel synchronization. Various actuator torque profiles can be used to achieve dynamic ‘walking’ in a hub-actuated rimless wheel. The proposed pulsed actuation torque gives rise to four torque regimes that achieve sustained walking and a fifth regime where the walker keeps slowing down with each step. The regimes can be identified based on the fraction of stance phase for which the actuator is energized. Theoretical analysis and experimental results are presented. A simple closed-form analytical solution, using hyperbolic functions, is proposed for the stance phase inverted pendulum dynamics considering planar motion. Ground impacts are assumed to cause abrupt drop in velocity. A constant braking torque that lumps together the effect of several loss phenomena is also considered. Based on whether the CoM is rising or falling and whether or not there is an actuating torque, a stance phase can have four types of sub-phases — actuated rise, unactuated rise, actuated fall, unactuated fall. These are concatenated in four different ways to form repeating cycles yielding the four regimes. The experimental set-up is a fixed step-angle walker constructed using two synchronized adjacent rimless wheels independently actuated at the hub. Varying the magnitude and duty ratio of the torque pulse, the four proposed regimes are experimentally shown. The mechanical power consumption and cost of transport are computed from measured motor currents for different average forward speeds. Videos of the walks are also taken. The space of operating points for an inverted pendulum based bipedal dynamic walker in terms of constraints and optimality is investigated. The operating point of the walker can be specified by the combination of initial mid-stance velocity (v0) and step angle (φm) chosen for a given walk. Not all operating points lead to a realizable steady-state gait. Using basic mechanics, a framework of physical constraints that limit the choice of operating points is proposed. The constraint lines thus obtained delimit the valid region of operation of the walker in the v0–φm plane. Within this allowable region, sub-regions that result in various regimes of walking are identified. A given average forward velocity vx,avg can be achieved by several combinations of v0 and φm. Only one of these combinations results in the minimum mechanical power consumption and can be considered the opti-mum operating point for the given vx,avg. A method is proposed for obtaining this optimal operating point based on tangency of the power and velocity contours. Putting together all such operating points for various vx,avg, a family of optimum operating points, called the optimal locus, is obtained. For the energy loss and internal energy models chosen, the optimal locus obtained has a largely constant step angle with increasing speed but tapers off at non-dimensional speeds close to unity. Thus, choosing the right step angle and keeping it fixed over a broad range of speeds could lead to an inverted pendulum walker that is close to optimal from a mechanical energy perspective. The complete hardware design for Chatur and the caveats associated with reliable performance of the mechanical and electrical subsystems are elaborated. In order to en-sure lateral stability, the system uses two contralateral wheels each driven by a separate BLDC hub motor. From a motor drive perspective, the mechanical load belongs to a unique class of dynamic loads whose reflected torque has a characteristic cyclic varia-tion that repeats several times within a mechanical revolution. The proposed control topology has two hierarchical levels, an inner loop for torque control of BLDC motor implemented using a standard proportional-integral controller, and an outer loop for torque reference generation that uses the information on the ground impact instants and the motor position feedback. Ground impacts of the spokes are detected by an accelerometer to initiate the application of torque. The torque pulse magnitude can be set internally or by a manual operator via radio control. The pulse duration is programmable and enables attainment of various torque regimes at different steady state speeds. The wheels are synchronized so that corresponding spokes on both wheels move in unison. This is achieved by including a wheel synchronization loop that compensates for any lag between the wheels. Lag is detected based on number of sector changes in the hall-effect position sensor data received from both motors. An improved BLDC motor drive is developed wherein non-commutating current feedback is used to reduce current spikes during sector transitions. Experimental waveforms for controller validation are shown.
54

Návrh a realizace demonstračního modelu dvojítého kyvadla / Design and implementation of demonstration model "double inverted pendulum"

Slabý, Vít January 2018 (has links)
This thesis describes the process of rebuilding an experimental model of a single pendulum on a cart into the double pendulum on a cart. The control algorithm in MATLAB/Simulink environment for stabilization of the pendulum in the inverse position is designed. For this purpose, LQR state feedback control was implemented. Also method for swinging the pendulum into inverse position from stable state (swing-up) was designed. Feedforward method was utilised for swing-up control. In the thesis, functionality of these algorithms is shown.
55

Realizace inverzního kyvadla typu Cubli / Inverted pendulum realization based on Cubli

Ježek, Michal January 2019 (has links)
This master thesis deals with the development and construction of the inverted pendulum, inspired by the Cubli project. The objective is to develop and design an inverted pendulum, in the shape of one side of the cube balancing at one of its corner and for balancing is used the flywheel. For its design 3D printing is used to the maximum extent and as the electronic parts commonly available components at an affordable price are used. The design of the construction and the components allow the construction of a complete cube, without the need of further development or fundamental changes in the design of the model. For the calculations and the design of the controller the Matlab / Simulink software was used. As the controller algorithm the LQR algorithm is used with added integral feedback, to minimize control error. The 3D models of the single parts are created with FreeCAD software and printed on a 3D Prusa i3 MK2S printer.
56

Návrh a řízení modelu laboratorního dvojitého kyvadla / Design and control of laboratory double pendulum model

Kirchner, Tomáš January 2020 (has links)
Improvement of the current double inverted pendulum model on a cart as well as a new LQG control and swing-up realization are the main goal of this thesis. Movement of the cart is driven by DC motor and gear belt mechanism. At first the control algorithms were simulated in Simulink program and then also implemented into the real system with MF624 card.
57

Control and balancing of a small vehicle with two wheels for autonomous driving

Batmanian, Saro, Naga, Pasam January 2019 (has links)
Control and balancing of an inverted pendulum has gained a lot of attention over the past few decades due to its unstable properties. This has become a great challenge for control engineers to verify and test the control theory. To control and balance an inverted pendulum, proportional integrated derivative (PID) method or linear quadratic regulator (LQR) method can be used through which a lot of simulations can be done using the represented theories.Since urban population is increasing at a very alarming rate, there is a need to discover new ways of transportation to meet the future challenges and demands. Scania has come up with a new conceptual bus called NXT which aims to develop a modular vehicle that should configure and re-configure themselves between different transportation tasks. NXT vehicle has front and rear drive modules which can be represented as single axle, two-wheeled vehicles which in-turn can be viewed as an inverted pendulum with a huge Center of Gravity. Controlling and balancing of the pod or drive module precisely and accurately is an interesting challenge since it is an unstable inverted pendulum with huge center of gravity (COG). This behaviour of the system has created a research question whether the module is controllable or not.Therefore this thesis focuses on the possibility of controlling the pod which is a two-wheeled inverted pendulum vehicle with a COG offset. Also, the thesis focuses on the construction, mod-elling, testing and validation of a down-scaled model, what sensors are needed to balance the pod precisely, how the sensors must be integrated with the system and how the pod can be controlled remotely from a certain distance by a human. The developed pod houses the technologies like sensors, BLDC motor controllers, hoverboard, Arduino board and Bluetooth transmitters.The Master Thesis starts by presenting an introduction to the inverted pendulum theories, Scania NXT project, information about the research methods, thesis outline and structure . It continues by describing related literature about the inverted pendulums, segways, hoverboards, motor controllers and Arduino boards. Afterwards, the process of deriving a mathematical model, together with simulation in Matlab, Simulink and Simscape is described. Later, construction of the pod is made and lot of effort is put to run the pod. Since the pod needs to be controlled remotely by a human, a remote controlled systemis implemented via mobile phone using an app and finally the thesis is finished with a conclusion and ideas for future work. / Reglering och balancering av en inverterad pendel har väckt stor uppmärksamhet över de senaste decennierna på grund av dess instabila egenskaper. Det har skapat stora utmaningar för regleringenjörer eftersom området tillåter test och verifikation av diverese lösningar. För reglering och balansering av en inverterad pendel, så kan en regulator med proportionell, integral och derivat (PID) konstanter eller en linjär kvadratisk regulator (LQR) användas tillsammans med simuleringar för att bekräfta teorin.I och med att stadsbefolkningen ökar i mycket hög takt, så uppstår behovet av att uppfinna nya transportmedel för att lösa framtida utmaningar och krav. Scania har tagit fram en ny konceptbuss som heter NXT, med målet att utveckla ett modulfordon som kommer att konfigurera och rekonfigurera sig själva mellan olika transportuppgifter. NXT-fordonet har fram- och bakdriv-moduler som kan representeras som enaxlade tvåhjuliga fordon, vilka i sin tur kan betraktas som en inverterad pendel med en stor massa. Att reglera och balansera drivmodulen på ett noggrant sätt är en utmaning eftersom det är ett mycket instabilt system med enorm massa och en okänd tyngdpunkt. Systemets beteende har skapat en forskningsfråga om modulen är reglerbar eller inte.Denna uppsats fokuserar därmed på möjligheterna att kunna reglera drivmodulen samt vilka begränsningar det finns. Uppsatsen fokuserar också på konstruktion, modellering, testning och validering av en nedskalad modell, vilka sensorer som krävs för att balansera drivmodulem, samt hur sensorerna måste integreras med systemet för att kunna fjärstyra fordonet från ett visst avstånd. Utveckingen av en sådan nedskalad modell berör olika områden såsom sensorer, BLDC-motorstyrenheter, hoverboard balanserings scootrar, Arduino kretskort och Bluetooth-sändare/mottagare.Uppsasten börjar med en introduction om olika inverterade pendel teorier, Scania NXT project, forskningsmetoder, en översikt och övergripande struktur. Vidare fortsätter beskrivining av relaterade litteratur om inverterade pendel, Segway, hoverboard, borstlösa motor styrenheter och Arduino kretskort. Senare fortsätter processen för att härleda matematiska modeller som beskirver systemet, tillsammans med simuleringar i Matlab, Simulink och Simscape. Därefter beskrivs konstruktionen av en nedskalad modell av drivmodulen och beskrivning av nödvändiga processer för att få hårdvara och mjkukvara att fungera ihop. Då fordonen ska ha möjlighet att fjärrstyras, så implementerades en bluetooth enhet tillsammans med en programmerbar mobil applikation. Slutligen avlutas uppsatsen med resultat, slutsats och diskussioner och förslag till framtida arbeten.
58

Extended Kalman Filter as Observer for a Hydrofoiling Watercraft : Modelling of a new hydrofoiling concept, based on the Spherical Inverted Pendulum Model

Thålin, Adam January 2022 (has links)
Hydrofoiling in general has the potential to revolutionize watercraft in the future since it allows smoother and faster transport on water with less energy consumption than traditional planning hulls. Even if the concept of hydrofoiling has been around since the last century, development in control theory and material science together with increased computing power has led to a growing interest for the technology. Especially in water sports such as speed sailing and surfing due to its superiority in speed and comfort. Researchers and students at the Engineering Mechanics Department at KTH, Royal Institute of Technology, Stockholm are working on a new type of watercraft, utilizing only one single hydrofoil with the intention to minimize drag for faster and smoother rides in various wave and weather conditions. The difficulties lie in understanding the relationship between actuators and the mechanics. This thesis is a continuation work from a previous thesis which designed a control strategy based on a model with 4 degrees of freedom (DOF). Due to simplifications and linearizations, the 4 DOF model was not rich enough to meet the performance requirements. This thesis presents a 6 DOF model by deriving the mechanical equations for the spherical inverted pendulum and actuation from the hydrofoiling module. The inverted pendulum model is a well-known control problem that can be solved with different strategies. By showing that the hydrofoiling concept can be modelled as an inverted pendulum, it is also shown that it can be controlled as an inverted pendulum. The derived model is used together with an Extended Kalman Filter to create an observer. The observer is validated with a spherical inverted pendulum model in Matlab and the block diagram environment, Simulink. Simulation results show that the 6 DOF model is able to produce accurate state estimation of the watercraft even in the presence of stochastic measurement noise. It is also concluded that viscous forces, that arise from the watercraft being partly surrounded by water and partly by air, need further investigation. / Principen för bärplan är att generera lyftkraft från vattnet på samma sätt som flygplansvingar genererar lyftkraft från luften för att lyfta farkostens skrov ur vattnet. Detta minskar motståndet från friktionen mellan skrov och vatten vilket möjliggör snabbare och jämnare transport på vatten med en lägre energiförbrukning än traditionella planande skrov. På senare år har tekniken fått ett uppsving i och med framsteg inom strömningsmekanik, reglerteknik och materiallära. Detta i takt med datorers ökande beräkningskraft har lett till att bärplanskonstruktioner har kunnat uppvisa en överlägsenhet i vattensporter som kappsegling och surfing när det kommer till fart och komfort. Forskare och studenter på avdelningen för farkostteknik och solidmekanik vid Kungliga Tekniska Högskolan, Stockholm arbetar med att ta fram en ny typ av farkost med en minimal bärplansdesign, FoilCart. Dess utformning gör att det mekaniska beteendet kan liknas vid en inverterad pendel, vilket är ett välkänt, olinjärt reglerproblem som kan lösas på flera sätt. Denna avhandling är ett vidarearbete som bygger på en modell med fyra frihetsgrader från en tidigare avhandling kring FoilCart-projektet. Modellen med fyra frihetsgrader var, på grund av förenklingar och linjärisering av systemdynamiken, bristfällig och kunde inte garantera en robust balansering av farkosten förutom i linjäriseringspunkten. Modellen som presenteras i denna avhandling har sex frihetsgrader. Mekaniken och systemdynamiken härleds från den sfäriska inverterade pendeln tillsammans med styrningen från bärplansmodulen, utan förenklingar och linjärisering. Modellen används i ett Kalmanfilter för att konstruera en observatör för tillståndsrekonstruktion. Den framtagna modellen valideras med en FoilCart-modell i Simulink. Resultaten visar att observatören kan ge en noggrann tillståndsrekonstruktion även vid simulerat mätbrus i mätsignalen. Avhandlingen syftar till att visa hur den inverterade pendelmodellen kan användas vid framtida implementation av rekonstruerad tillståndsåterkoppling. I och med avgränsningar i avhandlingen finns det också en del strömningsmekaniska aspekter som inte tagits med vid framtagningen av denna modell. Eftersom farkosten delvis är omgiven av vatten och delvis av luft skulle det vara intressant att undersöka om noggrannheten i tillståndsrekonstruktionen kan förbättras genom att använda avancerad strömningsmekanik.
59

Toward Adaptation of Data Enabled Predictive Control for Nonlinear Systems / Mot Anpassning av Dataaktiverad Prediktiv Kontroll för Icke-linjära System

Ghasemi, Hashem January 2022 (has links)
With the development of technology and availability of data, it is sometimes easier to learn the control policies directly from the data, rather than modeling a plant and designing a controller. Modeling a plant is not always possible due to the complexity of the plant. Data-enabled predictive control (DeePC) is a recently proposed approach that combines system identification, estimation, and control in a single optimization problem. DeePC is primarily designed for LTI systems. The purpose of this thesis is to extend the application of DeePC to nonlinear systems with a particular focus on a non-holonomic ground robot. To reach this goal, we decompose the system states into different working modes where each mode can be linearly approximated. Furthermore, the data collection policies were also evaluated to conclude how they affect the performance of the DeePC. We identified several key challenges in this direction, namely: data-demanding structure, high computational complexity, and performance deterioration with increased non-linearity. While these challenges prohibited the application of DeePC to the ground robot system; we successfully applied the method to a benchmark non-linear system, the inverted pendulum on cart problem, and studied the effect of various design choices on control performance. Our observations indicate potential areas of improvement toward enabling DeePC for highly nonlinear systems. / Med utvecklingen av teknik och tillgänglighet av data är det ibland enklare att lära sig styrpolicyerna direkt från data, snarare än att modellera ett system och designa en styrenhet. Att modellera ett system är inte alltid möjligt på grund av systemets komplexitet. Data aktiverad prediktiv kontroll (DeePC) är en nyligen föreslagen metod som kombinerar systemidentifiering, uppskattning och kontroll i ett enda optimeringsproblem. DeePC är främst designad för LTI-system. Syftet med denna avhandling är att utöka tillämpningen av DeePC till icke-linjära system med särskilt fokus på en icke-holonomisk markrobot. För att nå detta mål delar vi upp systemtillstånden i olika arbetslägen där varje läge kan approximeras linjärt. Dessutom utvärderades datainsamlingspolicyerna för att dra slutsatser om hur de påverkar DeePCs prestation. Vi identifierade ett antal nyckelutmaningar i denna riktning, nämligen: datakrävande struktur, hög beräkningskomplexitet och prestandaförsämring med ökad icke-linjäritet. Även om de utmaningerna hindrade tillämpningen av DeePC på markrobot systemet; har vi framgångsrikt tillämpat metoden på ett benchmark icke-linjärt system, problemet med inverterad pendel på vagn, och studerade effekten av olika designval på kontrollprestanda. Våra observationer indikerar potentiella förbättringsområden för att möjliggöra DeePC för mycket olinjära system.
60

Sensorgeführte Bewegungen stationärer Roboter / Sensor Guided Motions of Stationary Robots

Winkler, Alexander 22 March 2016 (has links) (PDF)
Den Kern der vorliegenden Arbeit bilden sog. sensorgeführte Roboterbewegungen, d. h. die Nutzung von Informationen externer Sensoren zur Regelung des Roboters. Da gängige Industrierobotersysteme üblicherweise positionsgeregelt sind und seitens der Robotersteuerung lediglich der Zugriff zu den Sollwerten der Lageregelkreise erlaubt wird, kann auch der Regelkreis der sensorgeführten Roboterbewegung nur über den Lageregelkreis geschlossen werden. Aus diesem Grunde werden hier nur positionsbasierte Regelungsansätze verfolgt. Die Kraft-/ Momentregelung gilt als eine der wichtigsten Varianten sensorgeführter Roboterbewegungen. Dementsprechend widmet sich auch ein großer Teil dieser Arbeit dem Thema, mit dem Ziel durch innovative und übersichtliche Regelalgorithmen die Akzeptanz der Kraft-/ Momentregelung in industriellen Produktionsprozessen zu erhöhen. Beginnend mit der eindimensionalen Kraftregelung führt der Weg dabei über Konzepte zur Konturenverfolgung und kraft-/ momentgeregelten Montageaufgaben hin zur Kooperation von Robotern. In einem weiteren Teil wird ein Konzept zur Kollisionsvermeidung zwischen Robotern und Hindernissen präsentiert. Es basiert auf dem Ansatz der virtuellen Potential- bzw. Kraftfelder. Dabei ruft das künstliche Feld eine Bewegung des Roboters hervor, die vom Hindernis weg führt. Um das Feld zu erzeugen, wird die Methode der künstlichen Punktladungen entwickelt. Diese werden auf der Oberfläche eines Hindernisses platziert und generieren dann das virtuelle Kraftfeld. Die Platzierung kann z. B. mithilfe der CAD-Daten des Hindernisses erfolgen. Bei bewegten Objekten müssen alle Ladungspositionen ständig aktualisiert werden. Für Lehr- und Präsentationszwecke ist das sog. inverse Pendel eine oft genutzte Regelstrecke. Sein Aufrichten und Stabilisieren ist auch mit Hilfe eines Industrieroboters möglich. Dazu beschäftigt sich ein Kapitel dieser Arbeit mit Fragen zur Modellbildung der Kombination inverses Pendel und Industrieroboter und mit Regelungskonzepten für das Aufschwingen und Balancieren. Letztendlichen wird in diesem Zusammenhang noch ein Visual-Servoing System präsentiert, dass den Neigungswinkel des Pendels mit einer Kamera bestimmt. Alle hier vorgestellten Konzepte und Algorithmen werden Anhand von praktischen Experimenten verifiziert. / This work deals with so-called sensor guided robot motions, which means using the data of external sensors to control the robot. The control loop of the sensor guided robot motion can be only closed around the position control loop, because industrial robot systems usually work position controlled and only access to the desired positions is enabled. For this reason here only position based control approaches are regarded. Force/torque control is a very important type of sensor guided robot motions. According to this, a good portion of this work deals with the subject of force/torque control. Thus, the acceptance of force/torque control in industrial production processes should be increased, by using innovative and clear control algorithms. For this purpose force control in one degree of freedom, contour-following, force/torque controlled assembling tasks and the cooperation between robots are discussed here in different chapters. Thereafter, a concept to collision avoidance between robots and obstacles is presented. It uses the approach of virtual potential/force fields. In this case the artificial field induces a robot motion away from the obstacle. The method of artificial charges is developed to generate this field. For this purpose virtual charges are placed on the surface of the obstacles. Placing of the charges can be performed using e.g. CAD data of the obstacles. Having moving obstacles charge positions must be updated continuously. The inverted pendulum is commonly used teaching students in control theory. The swinging up and the stabilization of the pendulum also can be performed by an industrial robot. One chapter of this work deals with modelling of the robot mounted inverted pendulum and control algorithms for its swinging up and its stabilization. Finally, in combination with the inverted pendulum a visual-servoing system is presented, which measures the pendulum inclination angle by camera. All concepts introduced in this work are verified by practical experiments.

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