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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.
61

Návrh a identifikace rozšířeného modelu MEMS gyroskopu / An Extended Model of a MEMS Gyroscope: Design and Identification

Vágner, Martin January 2016 (has links)
The thesis is aimed on measurement and modeling of MEMS gyroscopes based on input-output characteristics. The first part briefs the state of the art. The second part is dedicated to measurement methodology. Critical points and sources of uncertainty are discussed and evaluated using measurements or simulations. The last part shows key characteristics of MEMS gyroscopes based on the survey of a group of different sensor types. The results have revealed significant influence of supply voltage that causes bias drift of the gyroscope and bias drift of the internal temperature sensor. The error can be comparable to temperature drift; however, this effect is not addressed in the literature. The second observed effect is temperature dependency of angle random walk. In the last part, a general model of a MEMS gyroscope is rewritten to reflect observed effects. Moreover, the structure is selected to be easily extendable and the coefficients are expressed to allow a comparison of nominal parameters of different sensors.
62

Robot řízený mikroprocesorovou jednotkou PIC / Robot Controlled by PIC Microprocessor Unit

Heřman, Petr January 2015 (has links)
This thesis describes design of a cheap robot. It includes implementation of firmware of low level control unit based on microcontroller PIC. The firmware drives motors, gains sensors data and communicates with the high level control unit. Furthermore the thesis presents realisation of connection to the robotic operation system ROS and its standard structures allowing usage of existing packages for the robot teleoperation and displaying sensor data on the remote computer. The thesis finally reports experiments with the robot. The constructed prototype is the model of the robotic lawn mower, however the whole solution has universal usage.
63

Sensordatenfusion zur robusten Bewegungsschätzung eines autonomen Flugroboters

Wunschel, Daniel 24 October 2011 (has links)
Eine Voraussetzung um einen Flugregler für Flugroboter zu realisieren, ist die Wahrnehmung der Bewegungen dieses Roboters. Diese Arbeit beschreibt einen Ansatz zur Schätzung der Bewegung eines autonomen Flugroboters unter Verwendung relativ einfacher, leichter und kostengünstiger Sensoren. Mittels eines Erweiterten Kalman Filters werden Beschleunigungssensoren, Gyroskope, ein Ultraschallsensor, sowie ein Sensor zu Messung des optischen Flusses zu einer robusten Bewegungsschätzung kombiniert. Dabei wurden die einzelnen Sensoren hinsichtlich der Eigenschaften experimentell untersucht, welche für die anschließende Erstellung des Filters relevant sind. Am Ende werden die Resultate des Filters mit den Ergebnissen einer Simulation und eines externen Tracking-Systems verglichen.
64

Framtagning av ny cykelbelysning med ljussignalering / Development of new bicycle lights with signal lights

Ghorbani, Nathalie January 2018 (has links)
Syftet med projektet var att ta fram en ny cykelbelysning för att höja cyklisters säkerhet och förenkla trafikregler samt utförandet av signalering. Genom en nulägesanalys av befintliga produkter, elektronikkomponenter och slutanvändarnas uttalanden kunde kundbehov tas fram. Därefter rangordnades kundbehoven och en funktionslista tillsammans med en produktspecifikation kunde verkställas. Med dem som grund utfördes en idégenerering med flera olika lösningskoncept där ett val gjordes baserat på en Kesselringmatris. Det vinnande konceptet var ett par pedaler med integrerad belysning. Genom en accelerometer fungerar pedalen som en bromslykta och med hjälp av en extern kontroll kan körriktningsvisare sättas igång som projiceras på marken. Elektriciteten som behövs till pedalernas belysning genereras när cyklisten roterar pedalaxeln via en generator. Som slutsats uppfylldes projektets mål men mer arbete behöver göras kring projektets avgränsningar för en färdig produkt. / The purpose of the project was to develop a new bicycle light in order to improve cyclists’ safety and to make it easier for them to follow traffic regulations. Using a status analysis of existing products, electronics and the end users statements the customer needs could be documented. Then the needs were ranked and a function list together with a product specification was produced. With them as a base the brainstorming could begin where multiple concept solutions were made and one of them chosen as a winner through a Kesselring matrix. The winning concept was a pair of pedals with integrated lighting. With the help of an accelerometer the pedal worked as a brake light and with an external control system turn signals could be turned on and were projected on the ground. The electricity needed for the pedals light system is generated when the user rotates the pedal axis with the help of a generator. As a conclusion all the project goals were fulfilled but more work needs to be done regarding the projects limitations for a complete production ready product.
65

Simulation methods for the mechanical nonlinearity in MEMS gyroscopes

Putnik, Martin 16 September 2019 (has links)
Im Zuge der Miniaturisierung werden mechanische Nichtlinearitäten immer wichtiger für die Auslegung und Optimierung von mikromechanischen Drehratensensoren. Die vorliegende Arbeit beschäftigt sich mit neuen Simulationsmethoden zur Beschreibung dieser mechanischen Nichtlinearitäten. Die Methoden werden mit Benchmark-Simulationen und Messergebnissen validiert. Die Genauigkeit der neuen Simulationsmethoden erlaubt den Einsatz in der Designoptimierung von kommerziellen MEMS Drehratensensoren. / In this thesis, new simulation methods for the mechanical nonlinearities in microelectromechanical gyroscopes are developed and validated with benchmark simulations and experimental results. The benchmark simulations use transient finite element analysis that consider geometric nonlinear effects. Experimental results are from Laser Doppler Vibrometry and electrical measurements on wafer level. Two different simulation methods, the energy- and stiffness-based approach, are compared with respect to numerical performance and accuracy. In order to evaluate these methods, four different mechanical structures are taken into account: a doubly-clamped beam, a gyroscope test structure and two state-of-the-art gyroscopes with 1 and 2 axes. For the accuracy measurement, the simulated frequency shifts of modes are compared to the true frequency shifts that are developed from either benchmark simulation, Laser Doppler Vibrometry or electrical measurement. The presented methods allow to predict the frequency shift of modes accurately and with a minimum of computational cost. Furthermore, the methodologies allow to generate modal reduced order models which are compatible with common model order reduction in the field. This makes it possible to incorporate mechanical nonlinearity in already established reduced order models of gyroscopes. The simulation and modeling strategies are applicable for generic actuated structures that can be also in different fields of study such as the aerospace and earthquake engineering.

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