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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.
821

On Kinematic Modelling and Iterative Learning Control of Industrial Robots

Wallén, Johanna January 2008 (has links)
Good models of industrial robots are necessary in a variety of applications, such as mechanical design, performance simulation, control, diagnosis, supervision and offline programming. This motivates the need for good modelling tools. In the first part of this thesis the forward kinematic modelling of serial industrial robots is studied. The first steps towards a toolbox are implemented in the Maple programming language. A series of possible applications for the toolbox can be mentioned. One example is to estimate the pose of the robot tool using an extended Kalman filter by means of extra sensors mounted on the robot. The kinematic equations and the relations necessary for the extended Kalman filter can be derived in the modelling tool. Iterative learning control, ILC, using an estimate of the tool position can then improve the robot performance. The second part of the thesis is devoted to ILC, which is a control method that is applicable when the robot performs a repetitive movement starting from the same initial conditions every repetition. The algorithm compensates for repetitive errors by adding a correction signal to the reference. Studies where ILC is applied to a real industrial platform is less common in the literature, which motivates the work in this thesis. A first-order ILC filter with iteration-independent operators derived using a heuristic design approach is used, which results in a non-causal algorithm. A simulation study is made, where a flexible two-mass model is used as a simplified linear model of a single robot joint and the ILC algorithm applied is based on motor-angle measurements only. It is shown that when a model error is introduced in the relation between the arm and motor reference angle, it is not necessary that the error on the arm side is reduced as much as the error on the motor side, or in fact reduced at all. In the experiments the ILC algorithm is applied to a large-size commercial industrial robot, performing a circular motion that is relevant for a laser-cutting application. The same ILC design variables are used for all six motors and the learning is stopped after five iterations, which is motivated in practice by experimental results. Performance on the motor side and the corresponding performance on the arm side, using a laser-measurement system, is studied. Even though the result on the motor side is good, it is no guarantee that the errors on the arm side are decreasing. One has to be very careful when dealing with resonant systems when the controlled variable is not directly measured and included in the algorithm. This indicates that the results on the arm side may be improved when an estimate of, for example, the tool position is used in the ILC algorithm. / Bra modeller av industrirobotar behövs i en mängd olika tillämpningar, som till exempel mekanisk design, simulering av prestanda, reglering, diagnos, övervakning och offline-programmering. I första delen av avhandlingen studeras modellering av framåtkinematiken för en seriell robot och implementeringen av ett modelleringsverktyg, en toolbox, för kinematikmodellering i Maple beskrivs ingående. Ett antal möjliga tillämpningar för toolboxen kan nämnas. Ett exempel är att med hjälp av extra sensorer monterade på roboten och ett så kallat extended Kalmanfilter förbättra skattningen av positionen och orienteringen för robotverktyget. De kinematiska ekvationerna och sambanden som behövs för extended Kalmanfiltret kan beräknas med hjälp av modelleringsverktyget. Reglering genom iterativ inlärning - iterative learning control, ILC - där en skattning av verktygspositionen används, kan sedan förbättra robotens prestanda. Andra delen av avhandlingen är tillägnad ILC. Det är en reglermetod som är användbar när roboten utför en repetitiv rörelse som startar från samma initialvillkor varje gång. Algoritmen kompenserar för de repetitiva felen genom att addera en korrektionsterm till referenssignalen. Studier där ILC är tillämpad på en verklig industriell plattform är mindre vanligt i litteraturen, vilket motiverar arbetet i avhandlingen. Ett första ordningens ILC-filter med iterationsoberoende operatorer används. ILC-algoritmen är framtagen enligt ett heuristiskt tillvägagångssätt, vilket resulterar i en ickekausal algoritm. I en simuleringsstudie med en flexibel tvåmassemodell som en förenklad linjär modell av en enskild robotled, används en ILC-algoritm baserad endast på motorvinkelmätningar. Det visar sig att när ett modellfel introduceras i sambandet mellan arm- och motorvinkelreferensen, är det inte säkert att felet på armsidan minskar så mycket som felet på motorsidan, eller minskar överhuvudtaget. I experiment tillämpas ILC-algoritmen på en stor kommersiell industrirobot som utför en cirkelrörelse som är relevant för en laserskärningstillämpning. Samma designvariabler används för alla sex motorerna och inlärningen stoppas efter fem iterationer, vilket är motiverat i praktiken genom experimentella resultat. Prestanda på motorsidan studeras, och motsvarande prestanda på armsidan mäts med ett lasermätsystem. Trots goda resultat på motorsidan finns det inga garantier för minskande fel på armsidan. Stor försiktighet krävs när experimenten innefattar ett resonant system där den reglerade variabeln inte är mätt explicit och inkluderad i algoritmen. Detta visar på möjligheten att förbättra resultaten på armsidan då en skattning av till exempel verktygspositionen används i ILC-algoritmen. / <p>Report code: LiU-TEK-LIC-2008:1.</p>
822

Impact of an Ankle Foot Orthosis on Reactive Stepping in Healthy Young Adults Using a Lean-and-Release Paradigm

Twohy, Kyra Elizabeth 01 September 2020 (has links)
No description available.
823

Design and Implementation of Stewart Platform Robot for Robotics Course Laboratory

Peterson, Trent R 01 March 2020 (has links)
A Stewart Platform robot was designed, constructed, and programmed for use in Cal Poly’s ME 423 Robotics: Fundamentals and Applications laboratory section. A Stewart Platform is a parallel manipulator robot with six prismatic joints that has six degrees of freedom, able to be defined in both position and orientation. Its purpose is to supplement parallel robot material covered in lecture. Learning objectives include applying and verifying the Stewart Platform inverse kinematics and investigating the Stewart Platform’s operation, range of motion, and limitations. The Stewart Platform geometry and inverse kinematics were modeled and animated using MATLAB. The platform was then built using linear actuators, magnetic spherical bearings, and acrylic plates. Control of the Stewart Platform is achieved using an Arduino Due and a custom HexaMoto shield. Users interact with the system using a GUI created with MATLAB’s App Designer.
824

Model průmyslového robotického ramene / Industrial robotic arm model

Sobota, David January 2018 (has links)
This work deals with problematics if industrial robotic arms, with theirs constructions, controling and with theirs role in Industry 4.0. Work describes the process of development and realization of the industrial robotic arm model by 3D printing. Besides construction fo model, work deals with firmware, software and inversion kinematics crucial to controling. Model of robotic arm will be used as learning tool.
825

Optimalizace zavěšení závodního vozidla / Optimisation of Race Car Suspension

Gašpar, Dominik January 2018 (has links)
The thesis deals with the kinematic characteristics of vehicle suspension and its essential parameters, analysis and optimization for use on ride on unpaved surface. Subsequent analysis of change of kinematics on driving simulations shall verify the modifications made in terms of driving characteristics of the race car
826

Vývoj a návrh nízkonákladového manipulátoru pro interakci s okolím / Development and design of low cost and environment interaction manipulator

Štěpánek, Vojtěch January 2018 (has links)
This thesis is focused in design low cost robotic manipulator known as SCARA. Chapters are sorted chronological by degrees of manipulator development. Thesis will present metods of inverse kinematics, that determines intaraction between joint rotation and cartesian coordina-tes of gripper. Next it introduces flowcharts for controlling machine and explains the control software determinater especially for microcontroller called Arduino MEGA.
827

Návrh SW pro řízení delta robotu / Design of SW for control of the delta robot

Šimková, Kristýna January 2019 (has links)
This thesis deals with software creation for delt robot in TwinCAT 3 program. First part describes the general characteristics of a delta robot. Next part deals with hardware and PLC coding in TwinCAT 3 and the final part discusses the creation of an application.
828

Měření parametrů GNSS přijímačů / Measurement of GNSS receiver parameters

Beneš, Jiří January 2020 (has links)
Goal of this thesis is to propose and realize a viable method to determine static a dynamic parameters of GNSS receivers. Thesis begins with research of GNSS, foremostly determining position and associated uncertainties of measurement. Following chapter contains research of GNSS receivers, data flow and methods of evaluating parameters of such measurements. Summary of obtained information is then used to schedule measurements, assemble experiment and create evaluating metrics. Main selected evaluating metric is weighted histogram of deviations with extended information. Aplication of proposed metrics onto measurements of GNSS receivers augments available information of GNSS receiver accuracy for whole range of values. This metrics also supplies additional statistical information about course of measurement.
829

Senzorika a řízení pohybu pro humanoidního robota / Sensors and motion control for humanoid robot

Chlaň, Jakub January 2020 (has links)
The presented diploma thesis deals with the design and construction of a simple humanoid robot with two arms attached to a torso. The work was solved as a team project of two authors. Therefore, only the construction of the arm, which is inspired by the kinematics of the human arm is described in more detail. Its construction was the task of the author. An important part of the work is the selection of drives and sensors for the operation of the mechanism. Furthermore, the work presents the procedure of creating a kinematic model of the arms to solve the forward and inverse kinematics problem. For the possibility of motion control, the control of the control unit in Simulink was designed and the drive control was created.
830

The Angular Momentum of the Circumgalactic Medium and its Connection to Galaxies in the Illustris and TNG Simulations

DeFelippis, Daniel January 2021 (has links)
A galaxy's angular momentum is known to be correlated with its morphology: at a given mass, spiral galaxies have higher angular momenta than elliptical galaxies. A galaxy's angular momentum is also largely set by its formation history: in particular, how much gas and the kinematic state of the gas that both accretes onto it and is expelled in galactic outflows from AGN and supernovae. All gas inflowing to and outflowing from the galaxy interacts with gas in the region surrounding the galaxy called the circumgalactic medium (CGM), which means at a fundamental level, the CGM controls the angular momentum of the galaxy. Therefore, to really understand the origins of galactic angular momentum, it is necessary to understand the angular momentum of the CGM itself. In this dissertation, I present a series of projects aimed at studying angular momentum in the CGM using the Illustris and IllustrisTNG cosmological hydrodynamical simulations suites. In an appendix, I also present a project on searching a survey of neutral hydrogen for previously undetected ultra-faint dwarf galaxies in and around the Milky Way's CGM. First, to understand how present-day galaxies acquire their observed angular momentum, I analyze the evolution of the angular momentum of Lagrangian gas mass elements as they accrete onto dark matter halos, condense into Milky Way-scale galaxies, and join the z=0 stellar phase of those galaxies. I find that physical feedback from the galaxy is essential in order to produce reasonable values of galactic angular momentum, and that most of the effects of this feedback occur in the CGM, necessitating studying the angular momentum of the CGM itself. Following on from this result, I then characterize the angular momentum distribution and structure within the CGM of simulated galaxies over a much larger range of halo masses and redshifts, with the goal of determining if there are common angular momentum properties in CGM populations. I indeed find that the angular momentum of the CGM is larger and better aligned around disk galaxies that themselves have high angular momentum. I also identify rotating structures of cold gas that are generally present around galactic disks. This clear connection of the CGM to the galaxy motivated a detailed comparison to observations of cold CGM gas. I perform this comparison in the following chapter where I use the highest-resolution simulation from the IllustrisTNG suite of cosmological magneto-hydrodynamical simulations to generate synthetic observations of cold CGM gas around star-forming galaxies in order to study kinematics and compare them to line-of-sight observations of cold gas near comparable galaxies. With this direct comparison to observations of the CGM, I show that IllustrisTNG produces rotating CGM gas consistent with observations to a high degree. In the penultimate chapter I present unpublished work where I begin to examine angular momentum evolution in the CGM on much finer timescales than can be resolved with the cosmological simulations I have used thus far. Preliminary results suggest that gas can experience large changes in angular momentum very quickly, and that these changes may be connected to corresponding changes in the temperature of the gas. Finally, I conclude by summarizing my main results and briefly discussing what questions still remain unanswered and my plans and strategies for pursuing these questions in my future work.

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