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ROS framework utilization for autonomous mobile robot control system
Vávra, Patrik ; Krejsa, Jiří (referee) ; Appel, Martin (advisor)
Tato práce se zabývá vytvořením lokalizačního a navigačního systému mobilního robota pro vnitřní prostředí pomocí frameworku ROS. Stručně je zde představen projekt, v rámci kterého diplomová práce vznikla, a jeho cíle. V rešeršní části je v krátkosti popsán ROS framework, simulační prostředí Gazebo a senzory, kterými robot disponuje. Následuje vytvoření modelu robota a simulačního prostředí, v němž jsou vyzkoušeny lokalizační, navigační a další rutiny. V experimentální části je provedeno testování senzorů a popsáno využití jejich výstupů. Následně jsou upraveny a otestovány algoritmy ze simulace na reálném robotovi. V závěru jsou popsány vytvořené vzdělávací minihry. Hlavním výstupem této práce je funkční stavový automat, který umožňuje manuální ovládání, zadávání cílů pro navigaci a v případě potřeby zajistí autonomní nabití robota.
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Material nonlinear solution of structures made of plastics
Weis, Lukáš ; Krejsa,, Martin (referee) ; Králík,, Juraj (referee) ; Kytýr, Jiří (referee) ; Němec, Ivan (advisor)
The presented thesis focuses on static analysis of plastic structures, taking into account nonlinear behaviour of the material depending on the stress. The static analysis is performed using the finite element method. The difference between material linear and material nonlinear approach is illustratively described in the introduction. A shell finite element, which is enhanced by the possibility of further delamination into layers and integration points along its thickness, is suitable to be used for a numerical analysis of a plastic structures. Separate chapters are devoted to the integration of the resulting values over the height of the cross-section. The integration of the material stiffness matrix correctly reflects the emergence of eccentricity. A part of the attention is devoted to the numerical quadrature rules. Next chapter is devoted to material nonlinear models. Two approaches are described: a simpler one, using the isotropic nonlinear elastic model, and more general one, using the orthotropic plastic model. The theoretical description is complemented by the graphic interpretation of the criteria according to the individual authors. A significant portion of this work is devoted to the algorithmization of calculation procedures described in the theoretical chapters. The algorithmization itself is implemented in Fortran language into a dynamic-link library which is part of the software program RFEM 5 which is widely used in engineering practice. A part of the work is a study comparing the performance of the different technologies applicable for the algorithmization of the described issues. The agreement of the theoretical analysis of the material models and subsequent implementation within the RFEM 5 is demonstrated on the example of the bent cantilever. The thermoplastic aboveground tank structure is subject of detailed material linear, and nonlinear analysis respectively. The various approaches are compared on the results of stress, deformation an
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Stabilitní analýza ocelových konstrukcí s imperfekcemi
Kalina, Martin ; Krejsa, Martin (referee) ; Kala, Jiří (referee) ; Kala, Zdeněk (advisor)
The aim of this work is focused on soluti0on stability problem of planar bar structures. The calculation algorithms and methods used for analysis of behavior of these structures are described. The discrete computational model of steel of von Mises planar truss is presented. The structure deformation is evaluated by seeking the minimal potential energy. The effect of vertical displacement of top joint is determined by step-by-step method, and Newton iteration. Symmetric and asymmetric effects of initial shape of geometric imperfections of axes of struts are used in the model. The work is focused on another step in research of mapping of potential energy of elastic structures with aim at arch structures. For selected hinged arch loaded by displacement in the midpoint, the area of two concurrently existing postcritical statical equilibrium states is scanned using dynamical relaxation and applying of a set of designed mapping methods.
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Algorithms for design and analysis of membrane structures
Lang, Rostislav ; Krejsa,, Martin (referee) ; Kytýr, Jiří (referee) ; Němec, Ivan (advisor)
Předkládaná práce se zabývá problematikou navrhování membránových konstrukcí, a to především s ohledem na vývoj potřebných výpočetních nástrojů v rámci MKP programů. Po uvedení základních fyzikálních požadavků jednotlivých kroků při navrhování těchto konstrukcí budou dále prezentovány vybrané či navržené algoritmy. Kapitola form finding se zabývá analýzou tvaru membránových konstrukcí. Rovnovážný tvar je odvozen od požadavku na výsledné předpětí, specifikované okrajové podmínky a aplikované zatížení. Obecně se ale tento proces zabývá i samotným hledáním rovnovážné soustavy sil v prostoru. V důsledku této skutečnosti jsou součástí popisované analýzy také vhodné stabilizační metody. V této kapitole budou prezentovány jak zvolené postupy, tak i navržená stabilizační technika specializovaná na hledání tvarů kuželových membrán. Dále je také popsán navržený algoritmus pro řešení úloh optimalizujících tvary ohybově tuhých konstrukcí, které jsou spjaty s hledáním labilních rovnovážných konfigurací. Kapitola structural analysis je zaměřená především na fenomén vrásnění membrán. Tato náhlá ztráta stability silně ovlivňuje statickou i dynamickou odezvu membránových konstrukcí. V rámci této kapitoly je představena a verifikována navržená výpočetní metoda, modulárně aplikovatelná na lineární, nelineárně elastické i plastické materiály používané pro uvedené konstrukce. Kapitola cutting pattern generation se zabývá výpočtem střihových vzorů, nezbytných pro výrobní proces membránových konstrukcí. Pro tento proces je v rámci předkládané práce navržena kombinace dvou různých metod. Zvolená posloupnost algoritmů cílí na optimalizaci poměru rychlosti, obecnosti a přesnosti výpočtu. Zmíněné kapitoly jsou doplněny jednotlivými příklady, analyzovanými pomocí popisovaných algoritmů, které demonstrují konkrétní fyzikální problémy či nezbytné implementační procesy.
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Modification of assembly line for production of electromagnetically controlled pneumatic valves
Palacka, Martin ; Ripel, Tomáš (referee) ; Krejsa, Jiří (advisor)
This thesis deals with proposal of assembly line modification for production of electromagnetically controlled pneumatic valves. The beginning of this thesis is dedicated to the theoretical study the most common Poka-Yoke systems, which are used for mistake avoiding in assembly process. There is described analytical analysis FMEA, which is used for detection of weak place in process. The next chapter is focused on description of valves manufactured on this assembly line. Main part of thesis is dedicated to proposal for process modification and design solution with choosing of appropriate sensors for some operations. There are created documents as a flow-chart for control algorithm, FMEA and process flow-chart for proposal according to automotive standard and estimated budget with counted payback period for whole project in last part.
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Overview of methods for person identification using image processing
Palacka, Martin ; Březina, Lukáš (referee) ; Krejsa, Jiří (advisor)
This thesis deals with an overview of methods for person identification using image processing. The beginning of thesis is dedicated to the theoretical study of the skin segmentation method, its algorithm and different color spaces, which are used for identification by this method. The next algorithm is a method called boosted cascade of simple features, while focusing on description of this method, an OpenCV library, computing algorithm, image interpretation by integral image and speed of computation which is reached. The next chapter describes the PCA method, the principles of working, a description of the mathematical model, a study of gender recognition, the results and troubleshooting. The last described methods are fusion of facial strips and pixel patern based texture feature. At the end of this thesis there is the tested application of person identification and gender recognition and the results of the success of methods.
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Analysis of dynamical behaviour of slender structures and design of device to reduce vibration
Hanzlík, Tomáš ; Krejsa,, Martin (referee) ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Salajka, Vlastislav (advisor)
Thesis deals with the modeling of pedestrian excitation of structures and obtaining the corresponding dynamic response of the structure. The trend of modern slender structures places more emphasis on the accuracy of modeling pedestrian dynamic excitation, which is difficult because of the intelligent behavior of pedestrians and the biological nature of the modeled pedestrian. First part of the thesis deals with traditional models of pedestrian excitation, based on application of pedestrian ground force to the model of construction. Models are explored on a model of slender footbridge for many different excitation variants in order to explore the specifics of the force excitation application and the structure response calculation. In second part of the thesis biomechanical pedestrian models are developed, including inertial forces, to calculate the pedestrian interaction with the structure. Parametric studies carried out on simplified structural models research the influence of design parameters of biomechanical models on dynamic response. The aim is to obtain a more accurate model of the pedestrian-construction system for refinement of the design of structures. The design of a tuned mass dampers for the reduction of pedestrian induced vibrations is also explored. Tuned mass dampers are devoted to parametric studies that deal with the influence of design parameters of the damper on the efficiency and design requirements of the device. The aim is to explore the design parameters and their influence on the efficient and economical design of the device. In the thesis were developed two biomechanical models, a simple biomechanical model with one vertical degree of freedom and a bipedal model of a human walking. Models have proven a certain degree of interaction when exciting light footbridges by one pedestrian. Bipedal model then also brought a partial insight into the mechanics of walking and the causes of pedestrian contact forces.
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The exploitation of parallelization to numerical solutions regarding problems in nonlinear dynamics
Rek, Václav ; Krejsa,, Martin (referee) ; Vala, Jiří (referee) ; Němec, Ivan (advisor)
The main aim of this thesis is the exploration of the potential use of the parallelism of numerical computations in the field of nonlinear dynamics. In the last decade the dramatic onset of multicore and multi-processor systems in combination with the possibilities which now provide modern computer networks has risen. The complexity and size of the investigated models are constantly increasing due to the high computational complexity of computational tasks in dynamics and statics of structures, mainly because of the nonlinear character of the solved models. Any possibility to speed up such calculation procedures is more than desirable. This is a relatively new branch of science, therefore specific algorithms and parallel implementation are still in the stage of research and development which is attributed to the latest advances in computer hardware, which is growing rapidly. More questions are raised on how best to utilize the available computing power. The proposed parallel model is based on the explicit form of the finite element method, which naturaly provides the possibility of efficient parallelization. The possibilities of multicore processors, as well as parallel hybrid model combining both the possibilities of multicore processors, and the form of the parallelism on a computer network are investigated. The designed approaches are then examined in addressing of the numerical analysis regarding contact/impact phenomena of shell structures.
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Kinect v2 sensor usability in mobile robotics
Margetaj, Martin ; Kumpán, Pavel (referee) ; Krejsa, Jiří (advisor)
This thesis discusses parametres of senzor Kinect v2 and its usability in robotics. The work attempts to analyze and write correct installation steps of the drivers necessary for proper operation of the sensor under Ubuntu and framework ROS. The work contains a set of measurements that will be used for comparsion with the Hokuyo URG-04LX-UG01 sensor.
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Influence of technical and natural seismicity on building structures with focus on structures of masonry materials
Čada, Zdeněk ; Králik,, Juraj (referee) ; prof. Ing. Alois Materna, CSc., MBA (referee) ; Krejsa,, Martin (referee) ; Salajka, Vlastislav (advisor)
The dissertation deals with selected issues in the field of the calculation of the response of building structures which are excited with dynamic non-stationary displacement loading of its ground. Seismic load has been assumed. Procedures, how to work with seismic records with respect to the accuracy of dynamic calculations, how to modify the response spectrum to ensure the reliability, how to generate synthetic accelerogram requiring more accurate response, are recommended. Synthetic akcelerogram has been generated by own approaching, which has been used as the excitation function in the experimental seismic testing of autoclaved concrete brick building in model scale. Response values of motion in the measured points of the experiment were compared with the linear and nonlinear dynamic calculations by using the finite element method models. Different levels of detail of the numerical models have been used. The shear wall behaviour has been modelled by using constitutive models with brittle failure as well as using of non-linear interaction interface with possible delamination between the masonry bricks. The behaviour of the mathematical model of wall systems has been calibrated with respect to the measured data at shear wall experiments in real and model scale of walls.
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