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Automatic Detection of a Vessel Mooring at an Anchor Buoy in LPWAN Networks
Kejík, Petr ; Klusáček, Stanislav (referee) ; Kopečný, Lukáš (advisor)
This Master’s thesis deals with the design and construction of a maintenance-free unit for the detection of vessel mooring to an anchor buoy. The unit is powered by a battery with the possibility of running from another alternative source of power, in this particular case a solar panel. For wireless communication, the unit uses LoRa and NB-IoT technologies working in the LPWAN networks. During the designing phase, emphasis is placed on aspects such as maintenance-free duty, minimal consumption and the possibility of mounting on any type of buoy. The thesis also deals with the mechanical design of the device and design of the prototype of the detection element. The work is created in a cooperation with Netlia IoT s.r.o., which mainly deals with the custom production of devices using smart sensors and LPWAN communication technologies.
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Measuring system for acoustic characterisation of materials
Plánka, Mikuláš ; Havránek, Zdeněk (referee) ; Klusáček, Stanislav (advisor)
The diploma thesis deals with the measurement of acoustic parameters of the material using the B\&K 4206 impedance tube, specifically the absorption and reflection coefficients. The theoretical part provides a basic overview of the measurement methodology and a description of measurement quantities related to acoustic materials characterization. The measurement procedure using the PULSE LabShop software is also described in this work. The main focus of this thesis is the design and implementation of a custom open measurement system created in LabVIEW used to determine the aforementioned materials parameters. The results of the measurements using the custom implementation and the PULSE LabShop software are compared and evaluated in this diploma thesis.
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Angle of arrival calculation methods for localization using UWB technology
Žaludek, Ivo ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The thesis describes UWB technology, compares available hardware platforms and describes UWB localization methods. The practical part compares the methods of calculating the angle of arrival from the phase difference of signal arrival on the two-element antenna array. The calculation is performed using the analytically obtained arc sine function and also using the look-up table and the polynomial function. The content of the look-up table and the coefficients of the polynomial function are based on the measured characteristics of the UWB receiver (anchor). The best result was obtained using the look-up table. More accurate results were obtained when the phase difference of arrival values were averaged.
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Verification of rotor model properties for sleeve bearings
Šály, Timotej ; Hnidka, Jakub (referee) ; Klusáček, Stanislav (advisor)
This bachelor thesis deals with a professional research in the field of sleeve bearings and their diagnostic disorders. It describes the recognized methods of identification and technical diagnosis of these errors. Furthermore, it describes the features and possibilities provided by the rotor model RK4 in the simulation of sleeve bearings. Moreover, the thesis deals with the development of a laboratory task for students to demonstrate the diagnostic fault of oil whirl.
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Implementation and practical verification of methods for predictive identification of rolling bearings failures
Bár, Martin ; Havránek, Zdeněk (referee) ; Klusáček, Stanislav (advisor)
The aim of this thesis is to identify and classify rolling bearing failures. The first part of the thesis deals with the diagnosis of bearings using in-house measured data. Faults were introduced into two bearings. The first one was deformed and corroded. In the second bearing, the outer raceway was damaged. Vibration data was collected at regular intervals and processed in MATLAB. The values of the statistical features indicated faults in both bearings. Envelope analysis showed that both bearings had developed a fault on the outer raceway and a gradual fault on the cage. In the second part of this thesis, machine learning methods were used to classify defective bearings using the CWRU data set. The accelerometer data were divided into blocks in two ways. Vibration images were created from these blocks for convolutional neural networks (CNNs). The best prediction accuracy was achieved by 1D convolutional neural network (1DCNN) (99.2 %), followed by neural network (94.6 %) and SVM (94.4 %). Random Forest and SVM are the best methods when the training set is reduced, and among CNNs, MATLAB architecture and 1DCNN are the best. The most noise resistant method is Random Forest and neural network, and among CNNs, 1DCNN is the best. Methods using statistical features perform better than CNNs on extremely noisy data. Convolutional networks do not achieve good accuracy, which is probably due to the conversion of raw accelerometer data into vibration images.
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pH measurement
Žatečka, František ; Klusáček, Stanislav (referee) ; Beneš, Petr (advisor)
This bachelor thesis deals with principles of pH measurement with focus on measurements in concrete. The very beginning of the work describes basic principles of measurement. On those, basis a research of methods for measurements in concrete was done with priority on non-destructive methods. According to the theory a survey of Czech market was conducted. The last part of the work is description of experiments that are based on theory.
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Comparison of methods for identification of rolling bearing failures
Kokeš, Miroslav ; Hnidka,, Jakub (referee) ; Klusáček, Stanislav (advisor)
The aim of this master thesis is the comparison of selected methods and parameters for roller bearings diagnostics. Selected statistical parameters are kurtosis, crest factor, and parameter K(t). The other selected methods are envelope analysis, cepstral analysis, and ACEP method. These methods are implemented in LabVIEW software and compared based on noise resistance, computation speed, and overall capability of identifying roller bearing faults.
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Measurement of weak magnetic field in 3D space
Bár, Martin ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The aim of this thesis is to theoretically examine the magnetic field of miniature cylindrical NdFeB magnets, compare the simulation results to real-world measurements, and design a magnetic field probe using suitable sensors. A FEM simulation was conducted using Ansys AIM and FEMM 4.2. The simulation shows that the magnetic induction on the surface of the magnet depends on the diameter/height ratio. The simulation results also show that 21 µm thick protective layer of Ni-Cu-Ni metal on the surface of NdFeB magnets lowers flux density of the smallest magnet sample (1x1 mm) by up to 14 %. It was also concluded that a larger magnet edge radius results in a higher flux density on the surface of the magnet. The biggest differences between simulation data and data measured by the F.W. BELL gaussmeter occurred in the smallest magnet sample. Using the FEMM 4.2 simulation software, a three-axis magnetic field probe was designed. Potential problems with this probe design have been identified. A simple procedure for probe calibration was proposed.
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Laboratory demonstrator for vibrodiagnostics
Blecha, Martin ; Krejčí, Jakub (referee) ; Klusáček, Stanislav (advisor)
This thesis deals with a vibration diagnostics of objects, structures and machines. The theoretical part is divided into three chapters according to type of the measurement. The first part called Modal Analysis discusses the basis of vibration, methods of measurement, relevant technical equipment and principle of experimental modal analysis. The second and third chapters of the thesis are focused on the diagnosis of defects. Each chapter mentioned above describes diagnosed defects, used methods and procedure for the diagnosis. Another part of the thesis summarizes practical issues and results gained in the laboratory experiments. It begins with discovering parameters of the measured object using technical diagnostics – experimental modal analysis. In the next step the hardware concept design was created, including custom measuring application programmed in LabVIEW. One part of the design is the laboratory model which includes a structure for free mounting and a possibility of excitation by an electrodynamic exciter. The application is also modified to enable measurements with shaker excitation. Finally, applications cooperating with professional software ModalVIEW and BK Connect were developed in order to simplify the operation and increase the comfort.
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Impact hammer calibration
Bilík, Šimon ; Klusáček, Stanislav (referee) ; Beneš, Petr (advisor)
The theoretical part of this thesis focus on the description of the piezoelectric accelerometers and their use for the impact measurements. It also characterizes the construction and the calibration process of the impact hammers with the use of the piezoelectric accelerometers. The practical part describes the place of calibration with the calibration tools, identifies the source of the oscillations on the output signal of the accelerometer and suggests its compensation. Part of the thesis is a service program for the impact measurement, analysis and the impact hammer calibration. Thesis also describes the methodology of the calibration and quantifies the measurement uncertainty.
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