[dipl] Sähkötekniikan korkeakoulu / ELEC

Permanent URI for this collectionhttps://aaltodoc.aalto.fi/handle/123456789/22

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Now showing 1 - 20 of 3994
  • Automatic identification of converter output voltage nonlinearities
    (2024-12-23) Tuorila, Antti
    School of Electrical Engineering | Master's thesis
    In sensorless control of electric motors, reference voltage is often used in place of actual output voltage due to complexity of measuring pulse-width-modulated voltages. Difference between the reference and actual output voltage stems from converter nonlinearity and causes degradation in the controller performance. This thesis reviews methods of converter output voltage nonlinearity identification. Sources of converter nonlinearity are reviewed with detailed analysis based on the existing literature. A converter nonlinearity identification method is presented that constructs a lookup table of voltage-current value pairs. The identification is performed using a standard current controller commonly used in drives control. The converter nonlinearity is measured using standard internal measurements with standstill rotor. The identification method is validated with simulations and laboratory experiments. 𝛼 and 𝛽-axis oriented identification methods are compared as well as different methods of constructing the lookup table. Distortion of reference voltages by nonlinearity is recognized and the lookup table based identification is shown to improve the output voltage evaluation accuracy. The 𝛽-axis method is found to offer better identification accuracy as compared to 𝛼-axis method. Bidirectional current stepping is found to be a more tolerant method against measurement errors near zero current. The effectiveness of the identified lookup table is validated in sensorless flux vector control. The 𝛽-axis method is recommended over the conventional 𝛼-axis method due to its superior accuracy without increasing complexity. Future research could focus on offline processing of the identified lookup table to enhance adaptability to parameter variations.
  • Combined control of multiple power converters in a single control unit
    (2024-12-27) Reijola, Aaro
    School of Electrical Engineering | Master's thesis
    Variable frequency drives, which are used for example for motor control, consist of multiple power converters that are used to modify the amplitudes and frequencies of current and voltage as desired. These converters are controlled with software that is responsible not only for calculations related to the control-algorithms, but also to safety, supervision, diagnostics and communication between devices in the system. Typically, embedded devices, which in thesis are referred to as control units, are used to execute the control software. This thesis examines the potential for combined control of multiple converters in a single control unit in ABB’s ACS880 product family. The aim of the thesis is to identify what benefits could be achieved with a combined control structure, as well as identify what changes would be necessary to the current structure where each converter is individually controlled with its own control unit. Based on the investigation, it was found that a combined control structure could reduce the drives’ manufacturing costs, remove communication delays between parts of the system and allow displaying more comprehensive status information to the users. On the other hand, technical challenges were also identified, related to, for example, the physical interfaces of the control units and the structure of the control software. Different approaches were compared and analyzed based on these findings, for example from the point of view of multiprocessing. Ultimately, both the upsides and downsides depend on the design decisions that are made, and this thesis offers a tool for the client organization for making these decisions.
  • Evaluating the applicability of autonomous lidar-based flying algorithms for flying with uncrewed aerial vehicles inside forests
    (2024-12-20) Karhunen, Aleksi
    School of Electrical Engineering | Master's thesis
    Having the possibility to fly autonomously with uncrewed aerial vehicles (UAVs) inside forests would allow easier and faster data collection of forest interiors compared to traditional methods. Inside forests, the Global Navigation Satellite System (GNSS) is unreliable which necessitates the usage of, for example, lidars, to localize the UAV and sense obstacles in the path of the quadrotor. The aim of this thesis was to evaluate the applicability of different lidar-based path planners and simultaneous localization and mapping (SLAM) algorithms for flying inside forests. Based on the literature review and offline SLAM localization accuracy experiment, Integrated Planning and Control framework (IPC) and Long-Term Association lidar-inertial Odometry and Mapping (LTA-OM) were selected as the path planning and SLAM algorithm of the system, respectively. The algorithms were tested both in a simulator and a real forest environment with custom-built hardware. The performance of the system and its applicability for flying inside forests were evaluated by the success rate of flight missions and average flight speed during those missions. Real-world experiments were conducted in forests with varying levels of difficulty. The system showed promising performance, especially in easy forests with a target flight speed of 1 m/s. However, in medium-difficulty and difficult forests, the success rates were lower: 10 out of 15 flights were successful in the medium-difficulty forest, and 6 out of 15 flights were successful in the difficult forest. In addition, the average fight speed lowered from 0.77 m/s in the easy forest to 0.68 m/s in the medium-difficulty forest to 0.44 m/s in the difficult forest. Compared to previous studies using vision-based algorithms, the system demonstrated some improvements. However, while it cannot, in its current state, be considered a viable replacement for a human collecting data with a handheld lidar, several improvements were identified that could significantly enhance its performance. Based on the experiments conducted in this thesis, a testing scheme for autonomous flying systems for flying inside forests was proposed.
  • Comparative analysis of Life Cycle Assessment data sharing models for supply chains
    (2024-12-19) Strengell, Ville
    School of Electrical Engineering | Master's thesis
    The reliability of Life Cycle Assessment (LCA) is highly dependent on the quality of the data used. This thesis examines the current landscape of LCA data sharing within supply chains and collaborative consortia, with a particular focus on three critical aspects: interoperability, data provenance and scalability. The study evaluates three key data sharing architectures, Blockchain, International Data Spaces (IDS) and a Trusted Operator system, as well as three of the most prominent data formats, ILCD, EcoSpold and JSON-LD. Using a qualitative comparison, the analysis addresses criteria such as efficiency, data provenance, immutability, scalability, and security. The results reveal that IDS provides the best balance of scalability and flexibility, making it suitable for complex supply chain applications. While the choice of data format was found to be less critical, compatibility with regional databases and commonly used software remains essential.
  • Emulation of Gas Engine Dynamics in Uninterruptible Power Supply System
    (2024-12-31) Zohaib, Muhammad
    School of Electrical Engineering | Master's thesis
    In the quickly changing world of energy and environmental sustainability, replacing gas engines with efficient, eco-friendly models is increasingly essential [1]. Gas engines are reliable sources of electricity, but their reliance on fossil fuels is a major disadvantage. The gasoline engines pollute the environment and increase the concentration of greenhouse gas levels. Reducing the reliance on gasoline engines aligns with global efforts to develop sustainable power production technology, foster renewable energy sources, and combat climate change. Data centers require a very reliable power source in order to function continuously, prevent data loss, and reduce downtime. Uninterruptible Power Supply (UPS) systems are crucial for maintaining this constant power supply, guarding against blackouts, and maintaining the stability of critical data center functions. This thesis investigates using a UPS system to emulate gas engine dynamics (GED). The study models a dynamical system in two parts: first, the gasoline engine dynamical model that generates mechanical torque and rotor speed references; second, the Permanent Magnet Synchronous Generator (PMSG) model, where the gas engine model’s outputs are fed as inputs to the PMSG model to produce the required electrical power, which then serves as a reference for the UPS system to ensure stable, uninterrupted power. Next, the UPS’s functionality is looked at, with a focus on its ability to provide steady, dependable electricity. The generated emulation models (gas engine and PMSG) are validated by simulations, showing how well they regenerate the dynamics of gas engines and PMSG. The findings demonstrate that the UPS provides control and efficiency. It is a workable backup power option when reference input is produced by their integrated model. Nevertheless, additional output regulation strategies, such as fast frequency reserve, aid in reducing the dynamical influence of gas engines for application-specific needs. In conclusion, UPS technology’s simulation of gas engine dynamics offers a practical and sustainable backup power option.
  • Sähköautojen maksullisten latauspisteiden määräaikaisvarmentaminen
    (2024-12-24) Tiihonen, Panu
    School of Electrical Engineering | Master's thesis
    The rising popularity of electric cars in Finland has increased the number of paid electric car charging stations and their amount will increase even more in the future. This increase signifies that the number of electric meters that are subject to periodic verification, has also increased, even though there is not an inspection body in Finland that is approved by Finnish Safety and Chemicals Agency (Tukes) to perform periodic verifications on paid electric car charging stations in accordance with the Measuring Instruments Act. Therefore, it is important to create a periodic verification service that is in accordance with the Measuring Instruments Act. This thesis explores how a periodic verification service for paid electric car charging stations is made from the perspective of an inspection body. The topic was researched as a literature review, which reviews studies and publications about electric cars, charging of electric cars, laws and acts that affect the periodic verification of paid electric car charging stations. The literature review is used to form a complete picture of the current state of paid electric car charging stations for the theory part of the thesis. The research part of the thesis contains different parts that together form the periodic verification service for paid electric car charging stations. The research part of the thesis displays the documentation made for the service, the matters to consider in the verification process, verification measures and the selection and testing of the reference meter chosen for the verification service. As a result of this thesis Inspecta Tarkastus Oy became the first inspection body in Finland that has an accredited periodic verification service for paid electric car charging stations that is approved by Tukes. The periodic verification service includes the related documents, verification measures, the uncertainty analysis of the chosen reference meter and the work instructions made for Inspecta Tarkastus Oy.
  • Humidity robustness in power semiconductors with direct copper bonding and active metal brazing substrates
    (2024-12-10) Kosonen, Santeri
    School of Electrical Engineering | Master's thesis
    Power semiconductors have been found to cause over 31% of failures in the converter industry, prompting the initiation of industry-wide reliability testing on the most common power semiconductor in frequency converters, that is, insulated-gate bipolar transistor (IGBT). The popularity and effectiveness of IGBT modules have exposed them to harsher environments, such as water treatment plants and mines, characterized by high humidity and temperature. IGBT modules are commonly made with active metal brazing (AMB) or direct copper bonding (DCB) substrates. These substrates play a crucial role in the performance of the module, particularly in terms of thermal management and corrosion resistance. Therefore, understanding their robustness in humidity is crucial to achieving proper reliability. This thesis created two test setups for the purpose of conducting research on humidity-induced short-circuit failures caused by dendritic growth. DCB and AMB substrates were compared for dendritic growth. The IGBT modules produced with AMB or DCB substrates were exposed to a high-humidity, high-temperature, and high-voltage environment in a temperature–humidity chamber. Additionally, the baseplate of every IGBT module was connected to a pulsating bias voltage that induced electric fields. The IGBT modules were analyzed after testing using an optical microscope and its associated measurement software to measure the length of the dendrites. It was concluded that the electric fields generated through the baseplate affected dendritic growth. Furthermore, dendritic growth was significantly influenced by higher voltage and continuous electric field application. The results revealed that unlike the AMB substrates, no dendrites were observed with modules utilizing DCB substrates.
  • Analyzing digital continuity workflow, tools and benefits in the industrial environment
    (2024-12-31) Devi, Pirya
    School of Electrical Engineering | Master's thesis
    With the development of Industry 4.0, digitalization and automation have modernized industrial processes, prioritizing smooth data exchange and integration for better performance and improved efficiency. However, significant challenges persist in overcoming the gaps between design and automation systems, especially in maintaining constant data flow and interoperability. In this thesis a systematic digital continuity workflow was investigated and developed to overcome these challenges, focusing on the integration of Data Exchange in Process Industry (DEXPI) files with EcoStruxure Automation Expert (EAE) for bulk engineering and generating Supervisory Control and Data Acquisition (SCADA) applications using the AVEVA System Platform (ASP). The results demonstrated considerable improvements in time efficiency through automated instance generation, improved real-time monitoring, and scalable system integration. In addition, the integration of Open Platform Communications Unified Architecture (OPC UA) improved interoperability between control and visualization systems, facilitating seamless data flow and better communication. The study highlights the significant role of digital continuity in speeding up the industrial automation process by automating tasks, minimizing errors, and achieving efficient control through real-time monitoring.
  • Ocean Carbon Capture: A Multidisciplinary Review of Technological, Environmental and Economic perspectives
    (2024-12-25) Beversdorf, Hanna
    School of Electrical Engineering | Master's thesis
    The objective of this thesis is to review research done about ocean carbon capture and assess if the researched methods can feasibly capture carbon dioxide from oceanwater. Technological ocean carbon capture aims to mimic the natural carbon cycle of oceans. The research was done by performing a literature review of papers authored by multiple experts in the field from the past three decades. The result of the literature review was that the ocean carbon capture technology is mainly preformed through electrochemical methods used to alter the pH level of seawater in a controlled environment. The technology is in its early stages, and there are globally only a handful of prototypes and pilot plants. Climate change has impacted natural environments globally, even oceans. Ocean alkalinity has decreased, leading to less carbon dioxide being sequestrated. The different methods of ocean carbon capture may be used to extract carbon dioxide from the seawater or to increase ocean alkalinity, both of which enable more atmospheric carbon dioxide to dissolve into the water. The current challenge this technology faces is the transition from the lab into full- scale application. This thesis performed a feasibility study of a process that the company Equatic has deployed and intends to scale up to megatons of captured carbon. The study concluded that the process is efficient and feasible up to the scale of megatons, but cannot feasibly achieve gigatons. There was limited published information about some environmental details about the process, for example the quality of the discharge water. The process is only feasible if it does not cause additional harm to the natural environment. Finally, this thesis addresses the financial obstacles that ocean carbon capture faces by presenting a proposal to update emissions trading schemes. In the proposal, not only do emitters pay for their emissions, but conversely, negative emission technology providers receive a payment for the emissions they capture.
  • Proof of Concept for FedRelax on Kubernetes: An Implementation Guide
    (2024-11-27) Luong, Quynh
    School of Electrical Engineering | Master's thesis
    In recent years, federated learning has been introduced and gained interest in different research areas. The evolution of federated learning has enabled an ability to train models on distributed datasets residing on multiple devices while preserving data privacy. FedRelax, a novel federated learning approach, is designed to train a heterogeneous network of models. Kubernetes is the most popular container orchestration tool to handle distributed environment and facilitate the application deployment, scaling and management. This thesis aims to study the integration of cloud technologies and federated learning system to investigate the behavior of leveraging these technologies together in real-world scenarios. Specifically, the study explores the feasibility of implementing the FedRelax algorithm, an novel federated learning method, on a Kubernetes cluster. The thesis study includes the design and implementation documentation for a Proof of Concept (POC). The performance, scalability and fault tolerance of the POC will be evaluated through different experiments and test scenarios. A baseline approach that runs FedRelax locally will be used as a benchmark to analyze the performance of this POC. When comparing the POC with baseline approach, a model generated by POC has less accuracy and higher runtime due to the complexity of distributed environment. However, the implementation enable a reliable scaling and fault tolerance mechanisms. Even though there are still potential areas to improve, the results shows that it is feasible to implement FedRelax algorithm on Kubernetes environment and the algorithm can perform training in a distributed settings.
  • Demand response potential modelling in buildings – development of a calculation tool and process
    (2024-12-03) Lehto, Tuomas
    School of Electrical Engineering | Master's thesis
    Ongoing climate change, push for energy transition, and evolving consumer behaviour are the driving efforts to replace fossil fuels with renewable energy sources to reduce emissions and achieve the decarbonisation of the energy supply. In this context, electricity plays a crucial role in the transition to cleaner energy. However, modern technology and the increasing demand for continuous power require a reliable and stable grid operation, necessitating a constant balance between supply and demand. As the share of renewable energy grows, and the supply becomes less controllable, there is a shift toward leveraging demand-side management for grid balancing. This approach is addressed by European Transmission System Operators which encourage consumers to engage in grid balancing by utilising various demand response mechanisms. This thesis focuses on the development of a calculation tool for estimating the demand response potential and profits from the chosen case study building’s electric loads. The potential and profit calculations are based on historical hourly market prices and demand data. The calculations are conducted through an estimation scheme in which Python scripts control an external energy simulation tool that simulates the loads’ differentiated consumption patterns and eventually, the demand response potential and profits. The case study building’s data is obtained from Granlund Oy. Values needed in the calculation are obtained from manual verifications, and previous literature and studies. The results indicate that the most profitable marketplaces during the studied period (1.6. – 31.7.) were the manual frequency restoration reserve (mFRR) capacity market and the frequency containment reserve for disturbances (FCR-D) market. From the studied three scenarios, lighting had the highest potential and profits, consistently among each marketplace. Impacts on the calculation’s execution and profits caused by external and internal factors were also investigated. The results indicate that execution speed was primarily influenced by computational capacity and memory usage, particularly when the Python script externally controlled the energy simulation tool, while the profits were mainly determined by magnitude factors, load activation time and recovery time.
  • The impact of Quality Assurance and Security measures on software projects
    (2024-12-28) Renlund, Nico
    School of Electrical Engineering | Master's thesis
    The software industry is constantly evolving, demanding constant awareness of new threats and compliance with updated guidelines in the management of software projects. This thesis examines the integration of Quality Assurance (QA) and security measures within software development projects, highlighting their essential role in creating robust and reliable end products. This was achieved through the analysis of qualitative data collected from interviews with Huld QA and security experts, as well as with product managers and owners of Huld customer organizations. Additional insights were obtained from a review of internal communication channels. The obtained data allowed the identification of best practices, challenges, and areas of improvement in various software project environments. This thesis highlights the key aspects of implementing QA and security measures in software development, including their early integration and the importance of clearly defined requirements. Regarding working practices within and across projects, strong collaboration and the utilization of feedback loops are essential for improving the development process. In addition, the incorporation of a security-focused individual in each development team is emphasized. Finally, software tools are identified as critical components to ensure consistent and effective practices. Despite the valuable findings, this thesis acknowledges its limitations, particularly the dependence on qualitative data. Although it offers valuable context, it simultaneously lacks the completeness of quantitative validation. Future research could investigate the development of industry-specific metrics and methodologies to assess the impact of QA and security measures, thus closing this gap. By presenting implementable strategies, this thesis provides actionable approaches for improving software quality, reducing vulnerabilities, and promoting sustainable development practices that can be adapted in a variety of industries and organizational settings.
  • Loss Estimator for Electric Motors Driven With Model Predictive Pulse Pattern Control
    (2024-12-31) Lauriala, Johannes
    School of Electrical Engineering | Master's thesis
    Harmonic content of the supply voltage is an important design consideration for medium-voltage (MV) permanent magnet (PM) motors, because it can lead to increased losses in the motor, potentially causing issues with heating. Use of frequency converters for motor control commonly generates harmonics in the motor’s supply voltage. Calculating harmonic losses during the design stage of a PM motor is often time-consuming and complicated. This thesis investigated an alternative approach for calculating harmonic losses for a MV PM motor supplied with a frequency converter utilising model predictive pulse pattern control (MP3C) as a control algorithm. The objective was to develop a fast and streamlined method for MP3C loss estimation. The thesis adopted a statistical machine learning (ML)-based approach for MP3C loss estimation. During the thesis, an estimator program was developed that utilises ML models trained using pre-calculated loss data. The estimator program was implemented using Python and LightGBM ML framework. The program generates estimates with a set of multiple ML models in conjunction with an interpolation algorithm. Training data for the ML models was calculated with finite element method (FEM) using a simulated MP3C voltage waveform. The general feasibility of a ML-based loss estimation program was demonstrated in the thesis. The implemented program serves as a functional prototype for further development of this concept. Accuracy of estimations was not evaluated due to limited availability of the training data. The process for calculating the training data was identified as the key area where further development is needed, as the process requires a considerable amount of manual work. Continuing the automation efforts already undertaken in the thesis will likely increase the feasibility of the demonstrated approach.
  • Sound Quality of Bone Conduction Headphones
    (2024-12-17) Pahta, Arttu
    School of Electrical Engineering | Master's thesis
    Bone conduction (BC) headphones are increasingly popular due to their ability to maintain situational awareness. Situational awareness provides use cases in sports, conversation and possibly in augmented reality scenarios. However, the sound quality of BC headphones has been underexplored. This thesis studies the sound quality of BC headphones, particularly focusing on their frequency response and possible measurement methods for assessing frequency response. Unlike conventional air-conduction headphones, BC devices rely on sound vibrations transmitted through the bones of the skull, requiring new methodologies for accurate evaluation. A listening test was conducted to assess the frequency response of BC headphones, revealing weaknesses in low-frequency reproduction and mid-frequency variations. These characteristics are influenced by the mechanical properties of the headphones and the physiological aspects of bone conduction. This thesis also examines the transparency and air-conducted sound of BC headphones. The study demonstrates the potential for improvement in BC headphone performance through optimized measurement techniques and digital signal processing. The results provide valuable insights into understanding and enhancing the auditory experience of BC technology users.
  • Automatic testing software for a modular circuit board assembly test system
    (2024-12-24) Lankinen, Aleksi
    School of Electrical Engineering | Master's thesis
    This thesis builds upon a previous project that involved designing and constructing a printed circuit board assembly (PCBA) tester device, which supports the testing and analyzing of the Control-Interface PCBAs of various uninterruptible power supply (UPS) product families. The boards manage all UPS functionalities. However, limited software development left the tester underutilized and changed electrical safety regulations prohibited the use of the device in its current state. To address these issues, the hardware was revised by introducing redundant signal channels to critical safety functions, such as emergency power-off buttons and contactors, along with other enhancements like light indicators and high-voltage power supply measurement points. The software was outsourced to a third-party developer and implemented using the Agile model, which was chosen for its flexibility. Requirements and specifications for the software were gathered through stakeholder interviews. The iterative Agile sprints enabled rea-time feedback and continuous validation throughout the process. Final acceptance testing confirmed the implementation of key features, including a debugger parser feedback loop, a customizable test sequence, and an intuitive user interface. The test software and hardware changes were satisfactory to the stakeholders and regulations respectively. Increased usage and interest in the tester, along with updated documentation, allow for further enhancements and expanded capabilities.
  • Sähköjakeluverkon kyky vastaanottaa paikallista tuotantoa ja sen ajankohtainen mittaaminen
    (2024-12-18) Kettunen, Oskari
    School of Electrical Engineering | Master's thesis
    The increasing use of solar photovoltaic (PV) systems supports the growth of renewable energy sources but introduces challenges to distribution networks, such as voltage rise, harmonic distortion, and overloading of distribution transformers. This thesis aims to identify cost-effective solutions to manage these issues and improve network capacity. This thesis presents methods to mitigate the network impacts caused by solar PV systems. These include reactive and active power control and changes in network topology, such as closing loops and strengthening the distribution network by adding parallel conductors or increasing the cross-sectional area of existing ones. Additionally, the study addresses the role of advanced control methods, such as step voltage regulators (SVRs), onload tap changers (OLTCs), smart meters, and inverters, in optimizing network capacity. Using available data, it is possible to assess the network's capacity and optimize the integration of solar PV systems. The algorithms developed through simulations presented in this study support proactive planning and enhance network flexibility under the scenarios analyzed. The proposed solutions could potentially reduce the need for expensive network upgrades and enable a broader utilization of renewable energy. The thesis emphasizes the importance of leveraging data to develop sustainable and efficient electricity networks. It provides distribution system operators with concrete tools to achieve climate goals.
  • Foresail-1p CubeSat reliability analysis using FTA and FMECA
    (2024-12-17) Karanta, Suvi
    School of Electrical Engineering | Master's thesis
    University-class CubeSats are prone to in-orbit failures due to limited resources, wide usage of COTS components, and a high change-rate of the team members. In addition, reliability standards are not clearly defined for small satellite projects and the standards created for NASA or ESA projects are not realistic. This thesis presents a way of conducting a reliability analysis using Failure Modes, Effects and Criticality Analysis (FMECA) and Fault Tree Analysis (FTA) for CubeSats. The case example is the Foresail-1p CubeSat platform for which the FTA and FMECA will be applied to. This thesis facilitates the process of the FS1p reliability analysis which has been conducted by the Foresail team of Aalto University.
  • Sensitivity analysis of a Baltic sea winter navigation simulation tool
    (2024-12-31) Kainulainen, Antti
    School of Electrical Engineering | Master's thesis
    The Baltic Sea serves as a vital gateway to international trade, providing essential maritime access to countries bordering it. However, its unique environmental conditions present significant challenges, particularly during winter when extensive ice coverage impedes safe and efficient navigation. These challenges are most pronounced in the Bay of Bothnia, where prolonged ice coverage affects several important ports for Finland and Sweden. To support the decision-making processes of Finnish and Swedish authorities, Kulkarni et al. (2022) have developed a tool for simulating the Baltic Sea under various conditions, aimed at helping to ensure safe maritime operations in icy conditions. A recent validation analysis revealed discrepancies between the model’s outputs and observed real-world data, highlighting the need for further investigation. To address this, a comprehensive sensitivity analysis was conducted to evaluate the model’s responsiveness to its key input parameters. This analysis aims to guide future refinement efforts and enhance understanding of the model’s behavior. The sensitivity analysis was carried out in two parts using different analysis methods. The Elementary Effects method was employed to identify the most influential parameters, while the Sobol’ method provided quantitative insights into the model’s sensitivity. The results of these analyses are presented using graphical figures that represent the numerical findings. The analysis revealed that the model responds predictably to variations in input parameters, with no significant outliers detected. However, certain parameters exhibited lower-than-expected influence on the model’s outputs, suggesting areas for potential improvement. The implications of these findings for the model’s functionality and future development are discussed.
  • Design considerations for invasive electromyographic sensors
    (2024-12-29) Seuranen, Pyry
    School of Electrical Engineering | Master's thesis
    Electromyography (EMG) is the recording of electrical activities of the muscle and is applied in fields such as prosthetic control and neurorehabilitation. The recordings can be done either through non-invasive surface electromyography (sEMG) or invasive intramuscular electromyography (iEMG). The advantages of sEMG include ease of use and safety achieved through simple sensor placement over the skin, but it suffers from lower selectivity and accuracy. In contrast, the iEMG offers higher selectivity and accuracy by inserting the sensor into the muscle, but it requires biocompatibility, more complex sensor design, and precise sensor placement. The aim of this master’s thesis is to develop an in vitro process for iEMG sensor design. To achieve this, a commercial wire electrode was exposed to synthetic electric signals consisting of selected sine waves and chirps. The tests were done in vitro with a modified ballistic gel phantom in a controlled laboratory environment. The phantoms were carefully designed to closely replicate electrophysiological characteristics of the muscle tissue. The obtained data was used to systematically evaluate the electrode performance and derive electrical temporal/frequency parameters of sensor under development. The main findings of the study suggest that the in vitro testing process can sufficiently describe the presented iEMG sensors, as well as identify their characteristics that can be leveraged for further sensor developments. While the results are promising, and the applicability of the process is high, there is still room for improvement. Namely, the testing should be done with other electrodes and electrode setups as well as consideration of other design parameters should be considered. Still, the process is versatile and easy to expand upon, thus providing a sound platform for further research.
  • OPC UA Information Modeling of Internal Combustion Engine I/O Module
    (2024-12-21) Makkonen, Jonne
    School of Electrical Engineering | Master's thesis
    This thesis focuses on OPC UA information modeling of an Internal Combustion Engine (ICE) Input/Output Module (IOM). The objective is to develop information models that align closely with industry standards to enable seamless integration with devices from other vendors. The study presents information models using the latest OPC UA Field Exchange (FX) specification, which is designed specifically for field-level devices such as the Input/Output Module. The model is designed using Microsoft Visio and UaModeler tools. The study proposes a modular model in which physical attributes such as connectors and ports and logical functions are presented in a hierarchical structure. For future studies, it is recommended to create information models with other control modules and research the automatic generation of information models.