Mechanical and Industrial Engineering

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    Speed Control OF Brushless DC Motor Using Fuzzy controller
    (Mekelle University, 2025-11-09) Ambasajr Hadush
    Brushless DC motors are utilized in numerous industrial systems, serving customers, automotive system and applications. Unlike brushed dc motor, brushless motor use electronic commutation and offer several advantage such as compact size, improved performance and high efficient. The existing control method is unable to control speed of a BLDC motor with rapidly changing and uncertain load condition and also could not adapt to load variation with constant gain value. Thus, the main aim of this thesis is to develop a controller to control the motor on the basis of the parameters varying, rated speed and load variations to ensure a fixed output speed of the Brushless DC motor in the presence of different operating conditions. The fuzzy logic controller is an adjustable controller whose development is gradual and progressive towards becoming an efficient control system. In this thesis fuzzy logic has been used to control the speed of the BLDC motor, which offers accurate and precise control. We can validate effectiveness of the proposed method by develop simulation model in MATLAB-Simulink program. The anticipation of this thesis is that the Fuzzy Logic Controller will outperform PID controller of BLDC motor with respect to settling time (Ts), rise time, and percentage overshoot. In this thesis, the performance of BLDCM with PID control was analyzed and the results were compared with fuzzy control. The fuzzy controller proved to have a better speed response than PID control. In a fuzzy intelligent controller, the plant output is varied for obtaining speed control at operating condition. Using MATLAB/Simulink software, MATLAB models and control system simulation were done on the Brushless DC motor. The findings indicate that the intelligent fuzzy controller is better than the traditional PID controller.
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    DESIGN OF FUZZY LOGIC CONTROLLER BASED ANTILOCK BRAKING SYSTEM FOR PASSENGER CARS
    (Mekelle University, 2025-11-05) TESHOME GEBREZGHER ABRHA
    An Antilock Braking System (ABS) is designed to prevent wheel lock up when brakes are applied. But the behavior of various road surface is non-linear which makes it impossible to correctly predict the optimal brake forces that can be applied to minimize stopping distance while maintaining steer ability. In this thesis, a quarter car model has been selected and a mathematical and MATLAB/Simulink model of some of components of an ABS has been developed. A Fuzzy Logic Controller (FLC) was implemented to utilize different variables, such as optimal slip and brake pedal force based on a parameter, where error of slip and rate of error as input parameter and change of pressure as an output parameter. Then, the characteristics of the slip curve was analyzed throughout the entire braking period with and without FLCs. The antilock braking system with bang-bang control would stop the vehicle in 16.3 seconds, however, it fluctuated in slip, whereas using fuzzy controllers would stop the vehicle in 2.46 seconds. Fuzzy logic control process mimics human brain thinking because of decision making hence provides better functionality when handling real time control of the parameters than a simple bang-bang controller. Fuzzy logic controller is better in control slip, steer ability, and braking.
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    Feasibility study for off-grid PV/wind/battery hybrid system A case for four selected sites in Geba Catchment, Tigray, Ethiopia
    (Mekelle University, 2025-12-28) Welegebriel Wedajoo
    This thesis examines the viability of off-grid hybrid renewable energy systems in the Geba catchment area of Tigray, Ethiopia, where rural electrification remains low despite ongoing efforts, with national coverage lingering around 50% since 2018. The selected sites: Zban-Maydora, Manda, Agewo, and Adi-Selam were analyzed for their capacity to support these smaller-scale systems. Energy Demand and Forecasting: A local assessment of energy needs was conducted for households and service centers, revealing significant projected growth over the next five years. - System Design and Simulation: Using HOMER software, a feasibility study was performed to optimize hybrid energy systems for each site. Various sensitivity variables were analyzed, allowing for ranking based on their Net Present Cost (NPC). Economic evaluation: using RETScreen software indicated that all systems have negative Net Present Values (NPV), making them financially unviable. The Levelized Cost of Electricity (LCOE) ranged from 0.969 USD/kWh to 2.52 USD/kWh, well above the residential tariff of 0.08 USD/kWh (2019 EEU rates). Despite local communities' willingness to pay, the high upfront costs and inflation in Ethiopia make these systems impractical without external funding or subsidies. Conclusion: Off-grid hybrid energy systems are currently economically unviable for rural electrification due to high initial costs, inflation, and elevated LCOE. Feasibility may improve with external financial support, like subsidies from NGOs or government assistance. This study also addresses critiques of using RETScreen for hybrid systems, offering valuable insights for future rural electrification projects. Additional Findings: The research highlights renewable energy sources like solar and wind as sustainable alternatives to traditional energy, addressing health and environmental concerns. It also integrates HOMER and RETScreen software for multi-renewable hybrid systems and advanced load demand forecasting methods used by the Ethiopian Electric Utility (EEU). While off-grid renewable systems could help electrify remote villages, their financial feasibility is limited, necessitating external financial support or significant economic changes for viability.
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    Simulation-Based Investigation of Adaptive Suspension Control for Regional Road Conditions in Tigray
    (Mekelle University, 2025-11-19) Abraha Gebru
    This thesis presents the design, modeling, simulation, and performance evaluation of an adaptive suspension control system developed to improve vehicle dynamics under the diverse road conditions of the Tigray region, Ethiopia. Suspension systems are fundamental in enhancing ride comfort, handling, and overall vehicle stability. Conventional passive suspensions, while simple and cost-effective, lack adaptability to the rapidly changing and uneven road conditions prevalent in developing regions. In response, researchers have introduced various intelligent control techniques—such as PID, Fuzzy Logic, and Adaptive Neuro-Fuzzy Inference Systems (ANFIS)—to address these challenges. However, existing studies still face limitations in real-time adaptability, nonlinear response management, and system robustness across unpredictable terrains. To overcome these challenges, this study proposes a hybrid PID–ANFIS adaptive suspension control approach, combining the fast response of the PID controller with the learning and adaptability of ANFIS. A quarter-car model of a light-duty vehicle was developed in MATLAB/Simulink to simulate various representative road conditions, including paved, unpaved, bump, and hilly terrains. The controller’s performance was evaluated using key dynamic metrics: ride comfort (weighted RMS acceleration), suspension travel, and road holding ability. Simulation results demonstrated that the hybrid PID–ANFIS controller outperformed both the classical PID and passive suspension systems. Specifically, body acceleration was reduced by over 80%, suspension travel was maintained within safe mechanical limits, and tire force variation was minimized, improving road holding stability. The overshoot decreased from 72.33% (PID) to 19.73% (PID–ANFIS), while rise time improved from 34.71 ms to 12.59 ms, and the RMS error reduced from 0.05784 (passive) to 0.00026 (PID–ANFIS). Compared to prior studies reporting 70–78% improvement using hybrid controllers, the proposed system achieved higher performance gains due to optimized parameter tuning and adaptive learning capabilities. The results confirm that the proposed hybrid PID–ANFIS controller is an effective, terrain-adaptive solution capable of improving ride comfort, stability, and safety for vehicles operating in challenging regional road conditions. This work contributes a region-specific adaptive suspension model that can be applied to improve vehicle performance in developing areas with similar infrastructure characteristics.
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    Modeling, Simulation, and Experimental Validation of an Electrical-based Injera Baking Mitad System
    (Mekelle University, 2025-08-14) Ataklti Gedamu
    About 30 to 50 percent of Ethiopian households utilize energy for injera baking, and conventional charcoal-fired Mitads produce a lot of emissions (about 1.2 kg CO₂ per session). Although they provide an alternative, electric mitads have a thermal efficiency that is typically between 60 and 70 percent. By using numerical modeling of composite materials to optimize electric Mitad performance, this study fills a research void that hasn't been filled by previous experimental work. We verified 17 minutes to reach 148°C and baked 21 injeras at 3 minutes each (66.81% efficiency) using ANSYS transient thermal software to validate a baseline model (2.8 kW clay pan) against experimental data (<3% deviance). Three composites were assessed: [1] Heating time was shortened by 59% (7 minutes to 150°C) using 95% clay and 5% aluminum chips. and baking time to 2.5 minutes per injera, achieving 70.21% efficiency (0.47 kWh/session saved); [2] ceramic reached 150°C in 12.5 minutes but required reheating due to ~10°C temperature drops per cycle; [3] 60:40 clay-aluminum composite achieved 150°C in 9 minutes with stable heat retention (68.2% efficiency). The 95% clay-aluminum composite demonstrated 25% total energy reduction per cycle, potentially saving households ~120 kWh annually. This work enables future optimization of composites, insulation, and socioeconomic analysis of production costs versus energy/fuel savings.
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    MODELING AND SIMULATION OF A COMPACT ELECTRIC VEHICLE CONVERSION FOR ETHIOPIAN URBAN TRANSPORT USING MATLAB/SIMULINK
    (Mekelle University, 2025-11-19) HEAVEN AMANUEL
    Ethiopia’s transition to sustainable mobility is challenged by high fuel costs, import dependence, and limited access to affordable electric vehicles (EVs). This study develops a technically feasible and economically adaptable framework for converting internal combustion engine (ICE) vehicles to EVs, ensuring compliance with national retrofit standards and optimizing drivetrain integration, energy efficiency, and performance validation. A widely used 1993 Toyota Corolla was selected for conversion and equipped with a three-phase liquid-cooled BLDC motor rated at 20 kW nominal and 50 kW peak power, limited to 145 Nm torque per standard. The 121.6 V, 280 Ah LiFePO₄ battery pack (34.06 kWh) powered the system, while the original five-speed gearbox was retained to enhance torque delivery and maintain compatibility. Safety and auxiliary systems included vacuum-assisted braking, electric hydraulic steering, and a 600 A battery management system. The methodology encompassed powertrain sizing, component selection, and MATLAB/Simulink-based simulations using the FTP-75 urban cycle. Results showed a 261 km range per charge and 130.6 Wh/km energy consumption, indicating strong urban applicability. Compared with commercially available EVs such as the BYD Seagull, the converted vehicle exhibited comparable performance and efficiency. The originality of this work lies in its use of a locally available ICE platform, adherence to Ethiopian retrofit standards, and comprehensive simulation-based validation. These findings highlight the potential of vehicle retrofitting as a cost-effective strategy for electrifying Ethiopia’s existing fleet, reducing fuel dependency, and supporting national sustainability goals.
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    DEVELOPMENT AND SELECTION OF GLASS/SISAL AND SHEEP WOOL FIBER REINFORCED HYBRID POLYMER COMPOSITES FOR VEHICLE BUMPERS
    (Mekelle University, 2025-11-24) Mulu Gidey
    Background: A bumper is an essential part of a vehicle, engineered to absorb impacts and shield the front and rear during low-speed collisions. This research focuses on creating glass/sisal and sheep wool fiber-reinforced composites for bumpers, meeting the demand for lightweight, sustainable materials while fostering local economic growth through job creation. It seeks to substitute traditional heavy materials, decrease costs, and advance sustainability initiatives within the automotive sector. Objective: The primary objective of this research is to develop and select hybrid composite materials that combine glass, sisal, and wool fibers reinforced with epoxy resin for use in vehicle bumpers. Specific goals include enhancing the mechanical properties of natural fibers and optimizing the composite design for performance and cost-effectiveness. Method: The methodology involves treating sisal and wool fibers with sodium hydroxide to enhance their mechanical properties, followed by the fabrication of composites using hand lay-up techniques. A comprehensive series of mechanical tests based on ASTM standards assesses properties such as tensile strength, impact resistance, and water absorption. Result: The composites demonstrate a tensile strength of 114.07 MPa, impact resistance of 112.5 kJ/m², and the composite bumper can absorb a maximum energy of 49.34kJ/m2 with speed 2.22m/s, and also a weight of 3.8 kg, significantly lighter than traditional steel bumpers (5.16 kg). Software analysis using Genetic Algorithms optimized the design, achieving a maximum stress of 31 Mpa and a deflection of 89 mm under impact conditions, indicating superior performance compared to conventional materials. This study supports the transition to environmentally friendly materials in the automotive industry. Conclusion: This research substantiates that glass/sisal and wool fiber-reinforced composites are viable alternatives for automotive bumper applications, offering improved performance and reduced environmental impact, to reduced fuel consumption and local economic growth. The findings support the ongoing transition toward sustainable materials in the automotive industry and highlight the economic benefits associated with local fiber utilization.
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    Feasibility Study and Energy Management System of Mini Grid Hybrid Systems for Energy Intensive Industries: A Case Study of Industries in Mekelle
    (Mekelle University, 2025-05-30) Hiwot Nigusie
    Hybrid systems integrate renewable energy sources with battery storage to supply energy in offgrid or on-grid setups. Many studies on hybrid power generation focus primarily on rural electrification, the socio economic benefits for households and local communities and remote areas, often overlooking the impact on industrial development. This literature gap limits our understanding of how reliable electricity access could drive industrial growth, enhance productivity, and foster economic diversification. This study focused on the techno-economic feasibility of a mini hybrid power generation system for electrification of three energy intensive manufacturing industries that are located in Mekelle city of Tigray namely Mesfin Industrial Engineering, MOHA soft drinks industry, and Desta Alcohol & Liquor Factory. The aim was to study the feasibility of a hybrid renewable energy solution to make industries energy independent and provide sufficient power and tied them with reliable power system by avoiding their grid dependency. The software packages utilized is used to design, analyze, and optimize the hybrid power system were HOMER Pro modeling tool. The mini grid has a peak capacity of 230 kW requires 3005 kWh/day. The Generic PV system has a nominal capacity of 720 kW. The annual production is 1,321,381 kWh per year for Mesfin Industrial Engineering. The electric needs for MOHA soft drinks industry are met with 720 kW of PV, 320 kW of generator capacity, 330 kW of wind generation capacity with operating costs for energy of $388,003 per year without battery storage. An addition of 1,000 kWh of battery capacity is proposed. This will reduce the operating costs to $458,636 per year. A 50 kW of generator capacity, 1,000 kWh of battery capacity and for Desta Alcohol & Liquor Factory 50 kW of wind generation capacity, with operating costs of $154,451 per year. It is proposed that adding 110 kW of hydropower generation capacity would reduce operating costs to $154,421/yr.
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    Design and Experimental Evaluation of passive Solar Still under hottest and driest climate condition of Ethiopia: A case of lake-Afdera saline water
    (Mekelle University, 2024-12-25) Mohammed Ahmed Yasin
    Access to potable water remains a critical challenge globally, particularly in arid regions such as Ethiopia's Afar Region, where groundwater is often limited or contaminated with high levels of fluoride and salinity. This study investigates the design and performance of passive solar stills for desalinating saline water from Lake Afdera under extreme climatic conditions. The objective was to enhance the productivity of conventional single-slope, single-basin solar stills by incorporating black volcanic rocks as thermal energy-absorbing materials. Two solar still configurations a conventional design and a modified design with black volcanic rocks were constructed and experimentally evaluated over two days in Afdera. Parameters such as ambient temperature, water temperature, and hourly yield were recorded. To validate the results, the modified still was later tested under different environmental conditions at Mekelle University using thermocouples, PicoLog software, a pyranometer, and measuring jars for precise data collection. Results showed that the modified solar still significantly outperformed the conventional still in water yield, producing 3,482 ml and 3,800 ml over two days compared to 1,920 ml and 1,780 ml, respectively. It also demonstrated improved night-time performance, yielding 890 ml versus 340ml, due to better heat retention from the black rocks. Correlation analysis from the Mekelle validation indicated strong relationships between water yield and solar radiation (r = 0.60), rock temperature (r = 0.96), internal temperature (r = 0.85), and ambient temperature (r = 0.83). The modified system achieved 32.87% higher efficiency in Afdera than in Mekelle, highlighting the role of environmental conditions. The findings confirm that integrating black volcanic rocks into solar still design enhances efficiency and output, offering a cost-effective and sustainable desalination solution for arid, high radiation regions like Afar.
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    Feasibility Study of Integrated Hybrid Energy System for off-Grid Rural Electrification: Case of Three Village
    (Mekelle University, 2024-09-28) Yeshareg Yrgalem
    This research presents a feasibility study of an integrated hybrid energy system designed for off grid rural electrification in three villages in Ethiopia's Tigray region. With over 56% of Ethiopia's population lacking access to electricity, the National Electrification Program (NEP) aims to achieve universal electricity access by 2025, promoting a mix of grid and off-grid solutions. This study explores the potential of combining wind, solar, and biogas to create a sustainable energy model that aligns with the NEP's objectives. The objectives of this study are threefold: to assess the renewable energy resources available in the selected villages, to design and size the components of a hybrid energy system, and to evaluate the technical and economic feasibility of the proposed solution. The methodology involves data collection through site assessments, resource evaluations, load estimations, and modeling using the HOMER Pro software. The study evaluates the energy demands of Felege Mayat, May Shih, and Mayderhu villages, revealing daily energy requirements of 1673 kWh, 1215 kWh, and 785 kWh, respectively. The findings indicate that a hybrid system—combining wind, solar, and biogas—can deliver a sustainable, reliable, and cost-effective electricity supply, with levelized costs of electricity (COE) at $0.0139/kWh, $0.0158/kWh, and $0.0167/kWh for each village. This approach not only addresses the immediate energy needs in these rural communities but also promotes environmental sustainability by reducing dependence on traditional biomass. In conclusion, this thesis highlights the potential of integrated hybrid energy systems to bridge the energy gap in rural Ethiopia, promoting sustainable development and improving human wellbeing. Recommendations for future research and implementation strategies are provided to facilitate the adoption of such systems in similar contexts.