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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.
21

Robotizovaný adaptivní systém pro přesné broušení mechanických dílů / Robotized Adaptive System for Precise Grinding of Mechanical Components

Jech, Filip January 2021 (has links)
The aim of diploma theses is the design of an adaptive robotic workplace. The theoretical part focus on the division of robotic systems and the technical description of individual devices that were used in the implementation of the solution. The practical part contains an analysis of solutions and optimization of the entire production process in terms of minimizing the trajectory, smoothness of movements, time interval, which were analyzed in RoboSim software and in Roboshop software source code was created. Part of the theses is the design for an adaptive production process. The result of the work is an algorithm for controlling robot movements between individual processes. The theses contain a variant solution and possible innovative solutions for possible expansion of the workplace.
22

Plánování trajektorie robota v dynamicky měnícím se prostředí s ohledem na splnění specifického cíle

Koten, Jan January 2017 (has links)
The aim of the thesis is a trajectory optimization of robot in the Ketchup House competition. Environment mapping system is proposed to deal with this issue. As an ideal solution is chosen a method of familiar environment scanning using a camera module and lidar. Camera module and lidar provide a possibility to scan up to nine searched objects, instead of one object allowed by the previous solution. A proximity sensor supplements the whole system, so the efficiency of detection increase. To find a particular position of the object on the playing field, image processing methods are used, namely line detection and thresholding. Moreover, new playing strategy and a new way of representing the playing field are implemented. Robot K4, created by PEF MENDELU AiStorm team, serves for application of the system.
23

Lokale elektrophoretische Abscheidung keramischer Partikel in stationären inhomogenen elektrischen Feldern in polaren und unpolaren Lösemitteln und deren Mischungen / Local electrophoretic deposition of ceramic particles in static inhomogenous electric fields in polar and nonpolar media and mixtures thereof

Schäfer, Markus Manfred January 2021 (has links) (PDF)
Die Elektrophoretische Abscheidung (EPD) ist ein zweistufiger Prozess, bei dem geladene Partikel zunächst aufgrund eines elektrischen Feldes in einer Suspension bewegt und anschließend auf einer Oberfläche abgeschieden werden. Aufgrund der Möglichkeit zur kostengünstigen Massenproduktion von Filmen auf Oberflächen sowie darauf basierenden dreidimensionalen Mehrschichtsystemen, ist die EPD für die Industrie und die Medizin von großem Interesse. Der 3D-Druck ist dagegen weniger zur Massenproduktion, sondern vielmehr zur Herstellung von Prototypen in niedriger Stückzahl geeignet, was ihn jedoch nicht weniger interessant für Industrie und Medizin macht. Beim 3D-Druck wird das Material zum Aufbau einer dreidimensionalen Struktur lokal zur Verfügung gestellt, weshalb er den additiven Herstellungsverfahren zugeordnet werden kann. Eine Kombination beider Verfahren eröffnet neue Möglichkeiten zum Aufbau dreidimensionaler Strukturen. Da EPD theoretisch mit jedem geladenen Objekt, Material oder Molekül möglich ist, ließe sich das Potenzial des 3D-Drucks durch eine Kombination mit EPD signifikant steigern. Prototypen könnten aus einer Vielzahl an Materialien in einem schnellen und kostengünstigen additiven Herstellungsverfahren entstehen, wodurch die Möglichkeit zum Einsatz als Massenproduktionsverfahren gegeben ist. Eine Nutzung der EPD als 3D-Druck-Verfahren ist jedoch nur möglich, wenn es gelingt, die Abscheidung der Partikel lokal zu fokussieren und somit den Aufbau der dreidimensionalen Struktur zu steuern und zu kontrollieren. In der vorliegenden Arbeit wird untersucht, ob lokale Abscheidung von keramischen Partikeln durch EPD realisierbar ist und welche Bedingungen dazu vorliegen müssen. Insbesondere werden die Bewegungen der geladenen Partikel im inhomogenen elektrischen Feld analysiert und der Einfluss der Polarität des Suspensionsmediums auf die Partikelbewegung und die Partikelablagerung in einer selbstentwickelten Mikro-Flusskammer untersucht. Im unpolaren Medium Cyclohexan steigt die Bewegungsgeschwindigkeit der Partikel linear mit der angelegten Spannung, respektive der elektrischen Feldstärke. Die Bewegungsrichtung der Partikel erfolgt entsprechend ihrer positiven Ladung in Richtung der Kathode. Die Partikel scheiden sich als stäbchenförmige Deposition verteilt auf der Kathodenoberfläche ab. Die Häufigkeit der Ablagerung ist dabei an der Elektrodenspitze, also im Bereich der höchsten Feldstärke am größten. Die Stabilisierung der Partikel in einem unpolaren Lösemittel wird durch eine Oberflächenbeschichtung mit verschiedenen, strukturähnlichen Dispergatoren realisiert. Alle verwendeten Dispergator-Partikel-Systeme zeigen näherungsweise gleiches elektrophoretisches Verhalten. In Wasser bewegen sich die positiv geladenen Partikel bei einer angelegten Spannung von unter 3 V entgegen der elektrostatischen Kräfte in Richtung Anode, deren Oberfläche sie jedoch nicht erreichen, da sie vorher abgelenkt werden. Somit erfolgt keine Abscheidung der Partikel auf keiner der beiden Elektroden. Ab einer Spannung von 3 V beginnen sich Partikel im polaren Medium in Form einer dendritischen Struktur an der Kathodenspitze abzuscheiden. Bei Spannungen von mehr als 17 V beginnt in Wasser eine sichtbare Bildung von Gasblasen an der Anodenoberfläche. Beim Abriss der Blasen von der Oberfläche wird die vorhandene dendritische Struktur zerstört. In Mischungen aus Ethanol und Cyclohexan wird die Spannung von 5 V konstant gehalten und das Mischungsverhältnis der beiden Lösemittel, und somit die Polarität der Suspension, variiert. Bereits bei 0,1 Vol.-% Ethanol-Anteil, sowie ab 30 Vol.-% Ethanol findet eine Partikelbewegung in Richtung der Anode, also entgegen der elektrostatischen Kräfte, statt. Da die Partikel die Anodenoberfläche aufgrund der repulsiven Wechselwirkungen nicht erreichen, findet keine Abscheidung statt. Nur bei einem Ethanol-Anteil von 7,5 Vol.-% bis etwa 30 Vol.-% bewegen sich die Partikel in Richtung Kathode, wo sie sich auch abscheiden. Die merkwürdigen Bewegungsphänomene der Partikel in der Mikro-Flusskammer konnten nicht mit Sicherheit aufgeklärt werden. Induced-charge electroosmotic flow oder andere elektrokinetische Effekte könnten wirken und so die elektrophoretische Partikelbewegung überlagern oder beeinflussen. Gezeigt werden konnte jedoch, dass eine lokale Abscheidung von Partikeln mittels EPD möglich ist. Dazu ist unter den beschriebenen experimentellen Bedingungen in Wasser eine Spannung im Bereich zwischen 3 V und 17 V nötig, um lokal eine dendritische Struktur abzuscheiden. In reinem Cyclohexan und für bestimmte Mischungsverhältnisse von Ethanol und Cyclohexan erfolgt die Abscheidung bei jedem untersuchten Spannungswert. Anders als in Wasser ist die stäbchenförmige Abscheidung jedoch an mehreren Stellen auf der Elektrodenoberfläche zu beobachten. Dennoch kann auch hier von einer lokalen Abscheidung gesprochen werden, da die Wahrscheinlichkeit für die Abscheidung an der Elektrodenspitze am größten ist, was nach einiger Zeit zu einer lokal erhöhten Schichtdicke führt. / Electrophoretic deposition (EPD) is a two-stage process in which charged particles first move in a suspension due to an electric field and then deposit on a surface. Due to the possibility of cost-effective mass production of quasi two-dimensional films on a surface as well as three-dimensional multi-layer systems, the EPD is of great interest to industry and medicine. In contrast, 3D printing is less suitable for mass production, but rather appropriate for producing prototypes in low quantities. Nevertheless, it is not less interesting for industry and medicine than EPD. 3D printing can be assigned to additive manufacturing processes in which locally supplied material assembles into a three-dimensional structure. Novel possibilities for building three-dimensional structures are conceivable by combining the two established methods. Since EPD is theoretically possible with any charged object, material or molecule, the potential of 3D printing could be significantly enhanced by combining it with EPD. Prototypes could be made from a variety of materials in a fast and inexpensive additive manufacturing process, allowing for the possibility of being used as a mass production process. However, the use of the EPD as a 3D-printing process as a rapid prototyping technique is only possible if the deposition of the particles can be focused and thus a local control of the structure is possible The present work investigates whether local deposition of ceramic particles by EPD is feasible and what experimental conditions must be met. Therefore, the trajectories of the charged particles in the inhomogeneous electric field are analyzed and the influence of the polarity of the suspension medium on particle movement and particle deposition is investigated in a self-developed micro-flow chamber. In cyclohexane as a nonpolar medium, the velocity of the particles increases linearly with the applied voltage, respectively the electric field strength. The particle movement in the direction of the cathode corresponds to their positive charge. The particles deposit as rod-shaped depositions distributed on the cathode surface. The possibility for a deposition is increasing with increasing electric field strength and is highest at the tip of the electrode. The stabilization of the particles in a nonpolar solvent is realized by coating the particle surface with various dispersants with related chemical structures. Analogous electrophoretic behavior is observed for all dispersant-particle systems. In water, the positively charged particles move towards the anode at a voltage of less than 3 V, contrary to the electrostatic forces, but they do not reach the surface of the electrode as they are deflected. Thus, no deposition of the particles takes place on either electrode. Above a voltage of 3 V, particles begin to deposit in a dendritic structure at the cathode tip. Above 17 V, noticeable gas bubbles begin to emerge at the anode surface, which destroy the existing dendritic deposition during their breakup from the surface. In mixtures of ethanol and cyclohexane, the voltage of 5 V is kept constant while the mixing ratio of the two solvents, and thus the polarity of the suspension, varies. Already at 0.1 vol% Ethanol content, as well as from 30 vol% Ethanol a particle movement is detected in the direction of the anode, i.e. contrary to the electrostatic forces. Since the particles do not reach the anode surface due to the repulsive interactions, no particle deposition takes place. Solely in the range of an ethanol content of 7.5 vol% to about 30 vol% the particles move in the direction of the cathode, where they also deposit. The peculiar movement phenomena of the particles in the micro-flow chamber could not be clarified with certainty. Induced-charge electroosmotic flow or other electrokinetic effects could be at work and thus overlay or influence the electrophoretic particle movement. However, it has been shown that local deposition of particles is possible by means of EPD. For this purpose and under the described experimental conditions, a voltage in the range of 3 V to 17 V is necessary in water to locally deposit a dendritic structure. In pure cyclohexane and for certain ratios in ethanol-cyclohexane mixtures, the deposition takes place at every voltage examined. In contrast to water, rod-shaped depositions can be observed at several points on the electrode surface. Nevertheless, this can be referred to as local deposition, since the probability of deposition is highest at the electrode tip, which leads to a locally increased layer thickness after a certain time.
24

CAD orientierte Teach-In Simulation und Bewegungsoptimierung für beliebige Roboterbaureihen

Riedel, Mathias 13 May 2009 (has links)
Der Vortrag beschäftigt sich mit der Simulation von Handhabungs- Montage- und Fertigungsaufgaben mit Hilfe von einem bzw. mehreren miteinander zusammenarbeitender Industrieroboter. Es werden Möglichkeiten aufgezeigt, wie die Herangehensweise für den Aufbau einer solchen Simulation ist. Weiterhin wird auf das Thema der Glättung von Unstetigkeiten nach verschiedenen Verfahren und deren Auswirkung auf die Bahntrajektorie eingegangen.
25

State trajectory approach to the interpretation of self-organization in the Belousov-Zhabotinsky reaction

ZHYROVA, Anna January 2017 (has links)
The Belousov-Zhabotinsky reaction is a well-known model for investigating the self-organization manifestations in nature. The chemical reaction cascade is easy to control and measure in laboratory conditions, which makes the investigation of diverse scenarios of the system behavior possible. The aim of this thesis was to evaluate the course of the reaction under the assumption of multifractality of observed chemical patterns. The approach of the information entropy theory was applied to image analysis to assess the visible changes in the reaction oscillation. Furthermore, the new characteristics - point information gain entropy and point information gain entropy density - were also introduced. These values were used to construct the state trajectory of the complex system with unique oscillation states recognition by multivariate stochastic data analysis. The reliability of the developed approach was tested on numerous experiments, including the insufficiently-studied BZ reaction wave formation under the space constriction and distortion by re-shaking effect. It has been confirmed that each of the system states has its own characteristic spectrum of information entropy. The obtained state-trajectories for the BZ reaction allows researchers to study the changing system behavior in response to variation of the initial conditions and to make a prediction about state-trajectory evolution in the imminent future. It was showed that the information entropy calculation is an effective and cheap tool for non-invasive analysis of a wide range of self-organized systems. Finally, it may be implemented also to automate laborious tasks for different cell stage recognition in medicine and biology.
26

Vývoj a mezikulturní srovnání agrese u dětí mladšího školního věku / Development and cross-cultural comparison of aggression in school-age children

Bergerová, Hana January 2017 (has links)
The Master's thesis deals with the topic of aggression in children. It focusses on the different kinds of aggression, specifics of aggression in children in their developmental stages, developmental trajectories of aggression, gender differences in aggression, determinants of aggression, theories of origin of gender differences, and international comparisons of aggression. The objectives of the research was to examine specifics of aggression in a Czech sample group, compare Czech results with the results of other countries (Greece, France, Germany, Italy, Turkey, China, India, Venezuela, Colombia, Mexico and Peru), and examine the effect of age, gender, and sibling birth order on aggression. The mean of factors of aggression in the Czech sample was among the smallest of the countries mentioned above. We didn't find any significant difference among groups based on age, gender, or sibling birth order. Keywords: Relational aggression, physical aggression, developmental trajectories of aggression, The Fairy Tale Test
27

Mapování psychosociálních intervencí a přístupu pracovníků vybraných kontaktních center k uživatelům metamfetaminu / Mapping of psychosocial interventions and attitude of workers in selected low-threshold contact center to methamphetamine users

Mištová, Anna January 2017 (has links)
INTRODUCTION: Despite the unique status of methamphetamine on the Czech drug scene, where the number of problem MA users accounts for 3/4 of all problematic drug users, there is a minimal amount of literature in the literature on how to work with this target group in the addictological care system. OBJECTIVE: The practical part was to monitor the work and access to methamphetamine users in the selected k-centers. Attention was paid to presenting KC clients, perception of key motives in each phases of drug use trajectories, the process of working with clients from first contact to eventual mediation of treatment and description of the specifics of access to MA users. METHOD: The chosen sample was selected on the basis of deliberate targeted selection through the institution. The data were collected by semi-structured interview, which was fixed with audio recording and subsequently transcribed. The patterns capture method as used to analyze the data. FILE: The research sample consisted of eight communication partners (four men). They were employees of selected k-centers, always one worker per facility, from different regions of the Czech Republic, with various length of experience in field (2,5 to 16 years). RESULTS: KC clients are mostly MA users, often polyvalent users, combining MA with other...
28

Simulace reálné trajektorie golfového míčku z videa / Simulation of a Golf Ball Trajectory from Video

Hlobil, Marek January 2011 (has links)
This work deals with the golf ball flight simulation based on video recordings. The way how to determine the trajectory of a golf ball using several initial points is described here. For the ball recognition there are used computer vision techniques, particulary pattern recognition. The work covers physics of the golf ball, it deals with physical influences that occurs during the ball flight and it tries to describe the trajectory approximation.
29

Matematický popis trajektorie pohybu vozidla / Mathematical description of vehicle motion trajectory

Lorenczyk, Jiří January 2020 (has links)
The goal of this thesis is to nd types of curves which would allow for the construction of a path that could be traversed by a vehicle. It seems that a minimal constraint for such a path is the continuity of curve's curvature. This leads to a closer look at the three types of curves: Clothoids, which are able to smoothly connect straights with arcs of a constant curvature, interpolation quintic splines, which are C2 smooth in the interpolation nodes and -splines, these belong to the family of quintic polynomial curves too, however, they are characterised by the vector of parameters which modies the shape of the curve. The thesis is accompanied by an application allowing for manual construction of the path composed of spline curves.
30

Analýza dat z jedoucího vozidla / Data analysis from moving vehicle

Kvapil, Josef January 2011 (has links)
The thesis deals with data analysis obtained from the traffic simulator. The data are from trajectory of vehicle movement. The analysis are suggested to driving trajectory which are obtained from the characteristic parameters for the subsequent detection of the critical vehicle position. Analysis and evaluation of the detection critical vehicle position are solved in the Matlab program scripts.

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