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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

Design och framtagande av mätanordning för ström och effek på trefas ledare : Josi Periferi strömmeter / Design and construction of a measuring device for current and power on three phase conductors

Hedlund, Jonas, Hammarström, Simon January 2015 (has links)
The assignment is issued by Scania Maintence AB seeking a new approach to detect power changes in their industrial processes. The work has taken place at Ångströmslaboratoriet and tests have been performed at Scania AB Södertälje. Today’s society consumes enormous amount of energy. In both economically and environmental view, it is important that the processes are effective, with high power factor. There are many ways to measure power in the industry, what they all have in common is that the installation is advanced, requires time and planning. Only a competent electrician may install the measuring device in the distribution box. The purpose of the project is to build a prototype for power measurement that can be easily used outside the distribution box, thus simplifying the procedure and shortening the time required. By attaching sensors around the supply cable, the magnetic field asymmetric flux density can be used and induce voltage proportional to the current in the cable. The result is an instrument that with a computer calculates current, phase angle and power. Measurements of the current rms value showed that the maximum difference between our prototype and Scania Maintenances equipmentis up to 29 percent. However, for a longer time (> 15 minutes) the differences between the mean values are only 1.2 percent and the accuracy is calculated to +/-3.67A with 95% confidence intervals. Phase angle accuracy measured to plus 6 minus and 15 percent. / Uppgiften är utfärdat av Scania Maintenance AB som söker en ny metod för att se effektförändringar i deras industriprocesser. Arbetet har ägt rum i Ångströmlaboratoriet (Uppsala universitet) och tester har utförts hos Scania AB Södertälje. Dagens samhälle förbrukar enorma mängder energi. Med hänsyn till både miljöpåverkan och ekonomi är det viktigt att processer är effektiva med höga verkningsgrader. Det finns många sätt att mäta effekt inom industrin, det de har gemensamt är att installationen är avancerad, kräver tid och planering. Endast en behörig elektriker får installera mätanordningen. Projektets syfte är att ta fram en prototyp för effektmätning som enkelt kan anmodas utanför centralen och därmed förenkla ingreppet och förkorta tidsåtgången. Genom att fästa sensorer runt ingående matningskabel kan magnetfältets asymmetriska flödestäthet utnyttjas och inducera spänning proportionell mot den ström som går i ledarna. Resultatet är ett instrument som tillsammans med en dator beräknar ström, fasvinkel och effekt. Vid mätning av strömmens effektivvärde beräknades den maximala skillnaden mellan vår prototyp och Scania Maintenances nuvarande utrustning upp till 29 %. Dock under en längre tid (> 15 min) är skillnaderna av medelvärdet endast 1.2 % och noggrannheten beräknas till 3.67A med 95 % konfidensintervall. Fasvinkelns noggrannhet beräknades till plus 6 och minus 12 %.
22

Moderniserat styrprogram för vakuumugn

Persson, Christofer January 2015 (has links)
The aim of this project is to create a modern and advanced program for controlling a vacuum furnace used for brazing plate heat exchangers and which includes functions for remote monitoring. A DAQ-unit (Data Acquisition) made by National Instruments connects with an already existing vacuum furnace to send control signals and receive measurements. There is already a control program available for the vacuum furnace but it has a number of shortcomings which the new program is intended to solve. A PID controller is implemented to control the temperature of the furnace. Temperature control is of utmost importance to get the brazing process as stable as possible. Therefore, a simulator has been developed that simulates the entire brazing process. The simulator serves as a tool to optimize values ​​of the constants included in the PID control algorithm. Everything is written in the C# programming language. The braze process has from a code stand point been divided into five phases; lowering pressure, heating, brazing, cooling and finish. A comparison between the new and the old control software shows that heating process is much faster now and that when the correct temperature level has been reached, the temperature variation is considerably lower than before. The entire soldering process is shortened by almost two hours. Temperature control is more efficient and stable than before because of the constants calculated using the simulator and that a PID controller is used instead of a PD controller. New technology is implemented so that a much larger number of samples are obtained. Functions for user access to the history of previous brazing processes has been developed and an interface to easily adjust settings is implemented. Even a web interface for remote monitoring has been created.
23

A Quantitative Approach for Tuning a Mountain Bike Suspension

Waal, Steven 01 November 2020 (has links)
A method for tuning the spring rate and damping rate of a mountain bike suspension based on a data-driven procedure is presented. The design and development of a custom data acquisition system, known as the MTB~DAQ, capable of measuring acceleration data at the front and rear axles of a bike are discussed. These data are input into a model that is used to calculate the vertical acceleration and pitching angular acceleration response of the bike and rider. All geometric and dynamic properties of the bike and rider system are measured and built into the model. The model is tested and validated using image processing techniques. A genetic algorithm is implemented with the model and used to calculate the best spring rate and damping rate of the mountain bike suspension such that the vertical and pitching accelerations of the bike and rider are minimized for a given trail. Testing is done on a variety of different courses and the performance of the bike when tuned to the results of the genetic algorithm is discussed. While more fine tuning of the model is possible, the results show that the genetic algorithm and model accurately predict the best suspension settings for each course necessary to minimize the vertical and pitching accelerations of the bike and rider.
24

USB měřicí modul pro virtuální instrumentaci / USB Measurement Module for Virtual Instrumentation

Hanuš, Ivan January 2015 (has links)
The objective of this thesis is design of the universal USB measuring module for virtual instrumentation. The module is connected to PC via USB interface. The module have analog inputs and analog outputs. The inputs have some switchable ranges, adjustable high-pass and low-pass fiters. Also the module have the digital input-output unit with 8 channels with configurable data direction and voltage level. Physical layer for digital serial interfaces SPI/UART and I2C is also part of this unit. The module is able to communicate with LabVIEW enviroment. The teoretical part contains survey of the commercial USB modules for data acquisition and generation from various manufacturers with its basic parameters. Some selected modules are described in detail. Furthermore the thesis deals with possibilities of connecting the USB module with the LabVIEW enviroment. The practical part deals with the design of input-output circuits and with design of the module itself. Furthemore, tho communication protocol, utility library and demonstration LabVIEW software are described in this part. At the end of this part, there are results of verification measurements. The result of this thesis is completed universal USB measuring module with utility library and demonstration program.
25

Balkböjning och signalbehandling / Beam bending and signal processing

Forsling Ekblom, Albin, Ohlén, Rickard January 2021 (has links)
I laborationssalarna på KTH i Södertälje, som i huvudsak används till elektrorelaterade ämnen, har det funnits ett antal balkmodeller med monterade töjningsgivare. Dessa har inte använts på många år och det saknas vidare uppgifter om modellerna. Uppdraget bestod av att utarbeta en laboration till KTH:s undervisning. Laborationen skulle handla om balkböjning och signalbehandling, med tonvikt på̊ det senare. Som hjälpmedel skulle vi använda oss av balkmodellerna. I uppdraget ingick det också att undersöka balkmodellernas elektriska och mekaniska egenskaper. Med teknisk balkteori skulle en möjlig relation mellan nedböjning och töjning tas fram. Med balkmodellen i en bryggkoppling kunde dess signal via ett DAQ-kort överföras till en PC och LabVIEW för vidare behandling. I LabVIEW kan ett anpassat gränssnitt tas fram och för visning av valda parametrar. Bryggkopplingen balanseras med hjälp av en potentiometer. I gränssnittet kan spänningsförändringen i bryggan observeras när balken påverkas av nedböjning. Efter kalibrering av systemet kan töjning och nedböjning presenteras efter beräkningar i LabVIEW. För att erhålla en så stabil och brusfri signal som möjligt har gruppen använt sig avbåde ett hårdvarufilter av lågpass-typ och ett mjukvarufilter i LabVIEW. Signalen förstärks med hjälp av en OP-förstärkare innan den matas in i DAQ-kortet. Trots sin ålder kunde balkmodellerna fortfarande användas och ge stabila signaler för vidarebehandling. Modellerna kan med fördel användas i en laboration för studenter och färdigt underlag finns för detta. Laborationen bör öka förståelsen för hur en signal från en givare kan förstärkas, filtreras och behandlas vidare i detta fall för grundläggande hållfasthetsberäkningar. / In the laboratory at KTH in Södertälje, which are mainly used for electro-related subjects, there are a number of beam models with mounted strain gauges. These have not been used for many years and there is no further information about the models. The assignment consisted of preparing a laboratory task for KTH's teaching. The laboratory would consist of beam bending and signal processing, with emphasis on the latter. As an aid, the beam models will be used, these consisted of a fixed aluminum beam with mounted strain gauges. The assignment also includes examining the electrical and mechanical properties of the beam models. With technical beam theory, a possible relationship between deflection and strain would be developed. With the beam model connected in a bridge connection, its signal could be transferred via a DAQ card to a PC and LabVIEW for further processing. In LabVIEW, a custom interface can be created and for displaying selected parameters. The bridge coupling is balanced with the help of a potentiometer. In the interface, the voltage change in the bridge can be observed when the beam is affected by deflection. After calibration of the system in the interface, strain and deflection can be presented according to calculations in LabVIEW. To obtain as stable and noise-free a signal as possible, the group has used both a low-pass hardware filter and a LabVIEW software filter. The signal is amplified by an OP amplifier before being fed into the DAQ card. Despite their age, the beam models could still be used and give stable signals for further treatment. The models can be used to advantage in a laboratory for students and there is a ready basis for this. The laboratory should increase the understanding of how a signal from a sensor can be amplified, filtered and further processed in this case for basic strength calculations.
26

Návrh software jednoúčelového stroje pro výrobní testy / Design of software single purpose machine for manufacturing test

Janoušek, Roman January 2015 (has links)
This diploma thesis deals with design and implementation of software for control of manufacturing tests of pneumatic proportional valve Festo MPYE. The single-purpose testing device consists of a DAQ device, a pressure sensor and of electrically operated pneumatic valves. In the introduction of this thesis are outlined aims of thesis followed by introduction to single-purpose assemblies commonly used in practice. The main part of this thesis deals with analysis and with solving the issues of assigned product testing. The designed and implemented modular software for control of manufacturing tests of assigned product is presented as an outcome and this software is easily adjustable for tests of a different product. In the conclusion are assessed achieved aims.
27

A 64 Channel Transmit System for Single Echo Acquisition MRI

Feng, Ke 2011 August 1900 (has links)
Magnetic Resonance Imaging (MRI) is considered as a slow imaging technique. Various approaches to accelerate MRI imaging have been explored by researchers in the past decades. Earlier gradient based methods have reached the safety limit. Parallel receiving techniques achieve accelerations by reducing phase encoding steps. Among these methods, SEA Imaging achieved the highest possible acceleration by completely eliminating phase encoding. However, SEA imaging is limited to thin planar slices above the array due to the correction needed for the inherent phase cancellation caused by voxel-sized coils. A phase compensation gradient pulse is used for this correction in SEA imaging. This phase compensation is dependent on slice position and thickness as well as the orientation of the array elements, placing stringent restrictions on SEA imaging, limiting its applications. Converting the SEA system into Transmit / Receive (T/R) mode, which is the main purpose of this study, eliminates the requirement for phase compensation gradient because phase departed during transmit is refocused during receiving. Independent amplitude and phase control of RF pulse for each coil of a SEA array is achieved using a low cost scalable parallel transmit system design. The first 64-channel parallel transmitter for MRI in the world is constructed and tested. Software is also developed to control the phase and amplitude of all the 64 channels of RF excitation pulses independently through National Instruments DAQ system. The system consists of vector modulators controlled by digital controlled potentiometers, two-stage amplifiers and T/R switches on the transmit side. All these are combined with newly designed and constructed preamplifiers and the existing 64-channel parallel receivers on the receive side, leading to the only 64-channel parallel T/R system available for MRI. As a bonus, the system can be easily updated to full Transmit SENSE capability. Furthermore, simulations and images are done to synthesize transmit patterns thanks to the large channel count. Testing results show that the system is capable of 100W per channel simultaneous transmission. Using this system, transmit field can be synthesized by varying the phase and amplitude across channel without traditionally required complicated pulse sequences involving simultaneous RF and gradient fields. Curved slice excitation has conventionally been considered a difficult task for MRI, achievable only through complicated pulses sequences. Using this system and flexible array wrapped around the subject to be imaged, the system is able to excite curved slice using one shot. TR images indicate that the system is capable of high speed surface imaging at 200 frames per second following the surface of a flexible SEA array coil which has not been achieved using other methods in MRI.
28

Test et calibrations technologiques avec PICO-0.1 pour les futurs détecteurs de chambre à bulle de matière sombre de PICO

Chen, Simon 08 1900 (has links)
Parmi les douzaines d’expériences qui visent à découvrir la matière sombre, l’expérience de détection directe PICO utilise des détecteurs à liquide surchauffé comme moyen pour s’y prendre. La chambre à bulle PICO-40L remplie de C3F8, présentement située dans le laboratoire sous-terrain SNOLAB, est en cours de test en vue d’une recherche aveugle de WIMP (Weakly Interacting Massive Particle) d’une durée de 1 an. Pour assurer la stabilité du détecteur pendant les périodes de préparation et pendant l’acquisition de données, un logiciel de surveillance a été écrit. Un moyen fiable de surveiller les paramètres importants du détecteur et d’envoyer des alarmes en cas d’urgence joue un rôle important à non seulement au succès de PICO-40L, mais aussi au développement du futur détecteur PICO-500. Située à l’Université de Montréal, la chambre à bulle PICO-0.1 a été conçue afin de calibrer les nombreux événements de fond qui se présentent dans ce type de détecteur. De plus, cette chambre à bulle a été utilisée comme première tentative au monde de mesurer la diffusion Thomson sur un noyau d’atome en exposant le détecteur rempli de C3F8 à une source de gamma produite par la réaction 19F proton à alpha et gamma 16O à l’aide d’un faisceau de protons crée par l’accélérateur de particules de l’Université de Montréal. Ce type d’interaction s’avérera à un événement de fond important pour les expériences de détection directe de matière sombre à bas seuil. / Amongst the dozens of experiments aiming to be the first to claim a dark matter signal, PICO is a direct dark matter detection experiment that utilizes superheated liquid detectors as a means of doing so. The latest C3F8 filled PICO-40L bubble chamber currently located in the SNOLAB underground laboratory is under testing to prepare for a 1 live-year blinded WIMP (Weakly Interacting Massive Particle) search. To ensure the stability of the detector during both the testing and the data acquisition phases, a monitoring software was coded. A reliable way to monitor all the parameters and to send alerts accordingly plays an important role in not only the success of PICO-40L, but also the development of the future larger-scale PICO-500 detector. PICO-0.1 is a test bubble chamber located at the University of Montreal that was built to calibrate for the numerous background events that can occur in this kind of technology. This test chamber was also used as a world’s first attempt to measure the coherent (Thomson) photon scattering onto a nucleus by exposing the C3F8 filled detector to a gamma source produced by the 19F proton to alpha and gamma 16O reaction using a proton beam created by the University of Montreal particle accelerator. This kind of interaction will prove to be a significant background for future sub-keV direct dark matter detection experiments.
29

Metody analýzy vibračních signálů / Methods of analysis of vibration signals

Russ, David January 2016 (has links)
The main target of this master’s thesis is to focus on methods of analysis of vibration signals in electric machines. To get know the basic principles of the diagnostics methods, is important to clarify origin of the vibration signals and the impact they have. The selected methods were tested practically by measurement on electric machines. Measured data were processed in program LabVIEW. In this thesis were created programs which actually can be aplicated for complete vibrodiagnostics of electric machines in particular induction motors. The basic evaluation of vibration are the RMS value, Crest factor, time course and power spectrum. Results of this thesis are used to demonstrate how quickly and effectively can be vibration signals from electric machines evaluated.
30

Prediktivt underhåll baserat på mätning av linjeström i pumpmotor : Digital modellering med MCSA samt implementering av iba datainsamlingssystem

Salestedt, Morgan January 2020 (has links)
Med övergången från Industri 3.0 till Industri 4.0 kommer stora krav på utvecklingen av Prediktiva Underhållsmetoder (PU) för att skona både miljö och ekonomi från påfrestande haverier. I detta projekt utfördes en installation av ett iba datainsamlingssystem, som är ett bra exempel på utvecklingen mot Industri 4.0. Vidare togs en prediktiv modell som skattar återstående livslängd med metoden Motor Current Signature Analysis (MCSA), som baseras på linjeströmsmätning, fram i projektet. Metoden analyserade strömmen från två olika induktionsmotorer för kylvattenpumpar där det var en ny pump och en sliten pump. Induktionsmotorer används inte enbart i kylvattentillämpningar utan integreras frekvent i kommersiellt tillgänglig utrustning, så den prediktiva modellen har ett expanderbart användningsområde. Två tillvägagångssätt testades för att hitta signaturer i linjeströmmen. Först testades spektrum-analys med 10Hz och 1000Hz som samplingsfrekvenser med slutsatsen att högre samplingsfrekvens troligen behövs för ett trovärdigt resultat. Sedan testades Analys av signalegenskaper med ANOVA som gav en klar signatur för toppvärden i ström med slutsatsen att skillnaden i ström mellan ny och sliten pump var tydlig men kunde vara av installationstekniska skäl. En förenklad skattning av Remaining Useful Life (RUL) med tillhörande rekommendation av underhållsinsats togs fram för att visualisera resultatet. Rekommenderat fortsatt arbete med modellen var klassificeringsalgoritmer, anpassad datainsamlingsutrustning och förlängd datainsamlingsperiod. / With the transition from Industry 3.0 to Industry 4.0 follows great demands on the development of predictive maintenance (PU) in order to spare both the economy and the climate from costly breakdowns. An installation of a iba data acquisition system was applied in this project, which is a good example on the advances made through Industry 4.0. The project shows the development of a predictive model, which estimates the remaining life with the method motor current signature analysis (MCSA) that is based on phase current. Data was collected on two different induction motors for cooling water pumps, one new and one worn out pump. Induction motors are not only used in cooling water applications but are frequently applied in commercially available equipment, thus the method has a expandable use. Two methods were tested for finding signatures in the phase current. First, spectrum analysis with 10 and 1000Hz as sampling frequencies with the conclusion that a higher sampling frequency likely is needed for a reliable result. Secondly an analysis of signal properties with ANOVA was preformed. This gave a clear signature for peak values in the current with the conclusion that the difference between new and worn out pump was clear but could be the result of installation related issues. A simplified version of remaining useful life (RUL) with related maintenance procedure was developed to visualize the result. For continued work with this model it is recommended to develop classification algorithms, improve the data acquisition equipment and prolong the data acquisition period.

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