Theses supervised by Prof. Dr. İsmail Böğrekci
13 theses · Aydın Adnan Menderes University
Development of a robotic system with hybrid locomotion for both indoor and outdoor fire detection operations
In this thesis; a robotic system with ladder & obstacle climbing and fire detection capabilities was developed. The robotic system was designed and produced as adaptable for both indoor and outdoor applications. An adaptive three wheel legged locomotion system to provide the obstacle climbing and straight motions was developed. The mathematical models were derived for the hybrid locomotion system. "Direction Based Angle Calculation" approach was proposed and the required experimental tests were applied to check the performance of the robotic system with the developed algorithm. A motion decision algorithm to classify the obstacles as ladder, negligible or negotiable according to the height and shape of the obstacle was structured. "Fire Search and Find" and "Fire Detection" algorithms were constructed to find the fire candidates and to determine the probabilities. Several experimental tests were applied to the mechanicals systems and algorithms of the ladder climbing fire detection robot (Performance tests of motion and transmission systems, local path planning and obstacle avoidance, motion mode decision, fire detection). The obtained test results showed that the transmission and motion systems are capable for both ladder climbing and linear motions. The direction based angle calculation approach is suitable and satisfactory for local path planning and obstacle avoidance applications. The developed fire detection algorithm using the Faster R-CNN deep learning model also determines the probability of a fire source with the accuracy of 93%. Key Words: Obstacle Avoidance, Faster R-CNN Deep Learning Model, Hybrid Locomotion, Local Path Planning, Fire Detection Robot, Fire Search and Find
Material optimization for ladder climbing robot
In this thesis, a robotic system that is capable of obstacle and ladder climbing was designed with utilization of analytical calculations and numerical analysis. Designed robotic system is suitable to work in both domestic and industrial environment. With this purpose, hybrid transitional locomotion mechanism that consists of three wheels and legs was developed. In analytical calculations, robotic system that some structural elements' (coupling, shafts) materials were defined as S235 and other structural elements materials as PLA was modelled to calculate power, acceleration and torque requirement. Same material configuration were modelled to obtain similar outputs and applied to numerical analysis software ANSYS Rigid Body Dynamics. That comparison process between analytical and numerical solutions was used as verification of models. Numerical analysis was applied for chassis of the robot with S235, Al6061, PLA and ABS materials. Obtained results were used to analyze critical components of robot such as inner shaft, main shaft and outer gear to investigate of strength of materials. According to the obtained results from computations & analyses and energy efficiency, it was observed that it was the most suitable and optimum to manufacture the chassis of the robotic system using PLA material. It was also found that the developed system was required 67.5 Watt power in the operation. Key Words: Analytical Calculations, Design Optimization Basis on Strength and Efficiency, Ladder Climbing Robot, Material Selection, Numerical Analysis.
The development of fire detection robot
The aim of this thesis is to design and manufacture a fire detection robot that especially operates in industrial areas for fire inspection and early detection. Robot is designed and implemented to track prescribed paths with obstacle avoidance function through obstacle avoidance and motion planning units and to scan the environment in order to detect fire source using fire detection unit. Robot is able to track patrolling routes using virtual lines that defined to the motion planning unit. The design and implementation processes of the robot are as follow; the design and the development of mechanical, electronic systems and software. The design and the development of mechanical system; for the sketch drawings, dimensioning and solid state modeling of the robot, computer aided design and solid modelling computer programs were used. The carrier board of the robot is produced using wooden material and rigid plastic foam which are cheap, strong enough and easy to manufacture. Differential steering method is selected for semi-autonomous robot driving system and it is powered by four brushed DC (direct current) motors. The design and the development of electronic system; electronic circuits were designed and produced, instead of buying a commercial card. Both schematic diagrams and circuits of the data acquisition and control circuits are designed using Proteus electronic design program. These circuits are used to control the motion of the motors and establish a data flow between the laptop and the other peripheral sensing components. Software development; intelligent algorithms for obstacle avoidance and path tracking have been developed. A sensor data fusion algorithm for the sensors was also developed to get more reliable fire detection information. In conclusion; a fire inspection and detection robot with various functions to especially can be used in industrial areas was designed and manufactured. The functions of the robot were tested. It can be concluded that system is able to detect the fire source maximum 100 cm distance away while robot is moving with 0.5 m/s forward speed. Keywords: Data acquisition and control, Differential steering method, Firefighting, Sensor data fusion, Virtual path tracking.
3D design and development of unmanned underwater vehicle
Amaç: Su altı robotunda modül ve malzeme AR-GE süreci, daha güvenli su altı insansız araçlarının oluşmasını sağlar Bu teknolojide ülkemizin üç tarafı denizlerle çevrili gelecekte dünya liderleri arasında yerimizi almak hayal olarak asla düşünülmemelidir. Bu nedenle bu çalışmanın amacı, insansız sualtı araçları projesinde gelişim hedeflemektir. Materyal ve Yöntem: Bir Otonom Su Altı Aracı projesi boyunca görevlerin çözülmesi ile yürütülen dört ana başlık vardır. Bu 4 önemli başlık Mekanik Tasarım, Yazılım, Elektronik ve Güvenlik konularıdır. Mekanik Tasarım çözümüne, model için bilgisayar destekli çizim programları kullanılarak ulaşılmıştır. Ardından, amacında ve görevinde hassas ve etkili olabilmek için Otonom Su Altı Aracı yazılımları devreye girmiştir. Renge göre görüntü işlenmesinden sorumlu algoritma geliştirilmiştir. Bulgular: Elektronik, mekanik ve algoritma ön tasarımları tamamlandıktan sonra bu tasarımların uygulama ve test aşamalarına geçildi. Motorları taşıyan ve havuzda su akışını sağlayan pervanelerin 3 boyutlu baskısı tamamlandı. Daha sonra araca 40A dirençli ve daha kalın kablolu ESC entegre edildi. Raspberry Pi ile Pixhawk arasındaki bağlantı telemetri portu üzerinden sağlandı. 400A iki adet bakır levha sipariş edilmiş ve Raspberry Pi aşırı ısınmasını önlemek için metal soğutucu entegre edilmiştir. Son olarak sonar ve buzzer sensörlerinden daha verimli veri alabilmek için bu sensörlerin suya dayanıklı modelleri sipariş edilmiştir. Sonuç: Literatür taramaları ve çalışmalar sonucunda SolidWorks adlı 3D çizim programında bir mekanik tasarım yapıldı ve 3D yazıcı kullanılarak üretim gerçekleştirildi. Ayrıca, sualtı koşulları hesaplandı ve motorlar, ESC'ler ve güç üniteleri gibi malzemeler seçildi ve tedarik edildi. Araçta otonom özellikler sağlamak için, sensörler, Raspberry Pi minibilgisayarı ve Pixhawk uçuş kontrol kartı kullanıldı ve gerekli sürüş ve görüntü işleme yazılımı yapıldı. Araçta kullanılan elektronik sensörler, daha ileri çalışmaları yönlendirmek için daha verimli bir şekilde kullanılabilir. Anahtar Kelimeler: 3B Dizayn, Görüntü işleme, İnsansız, Otonom, Su altı
Designing and manufacturing small scale autonomous vehicle
Purpose: Mobility, which is an indispensable part of the daily session, has numerous advantages, but also has disadvantages with user generalizations and prolonged travel time. If we call the process of arriving from one place to another; Errors occur within these stations with regard to people serving as users. The aim of this research is to obtain an unmanned drive for eliminating human errors and factors that mean human life as much as possible. Materials and Methods: Research and design were done in a reasonable and feasible way in the light of previous studies in engineering history. The position of the AV was determined by calculations together with the GPS module, and it was ensured to reach the desired target by means of the magnetometer. While going to the target, variables such as heading angle, position, distance to be traveled are calculated by the microprocessor. The obstacles that the AV encounters during its direction to the target are detected by ultrasonic sensors. In this AV, which has 5 ultrasonic sensors in total, 3 in the front and 2 in the sides, it is ensured that it reaches the target by creating new routes without getting caught in obstacles during its movement. With the experiments and calculations made, a wide obstacle detection area was created by giving 10-degree angles between the 3 sensors in front. Results: The autonomous vehicle has reached the determined position, which can be considered accurate. Regardless of the starting point, it arrived at the defined destination in an area with a diameter of 5 meters. Considering the costs of the sensors, simple algorithm, not very powerful processor and circuit elements, sufficient success has been achieved. Conclusion: It has been observed that the autonomous vehicle designed in accordance with its purpose is positioned within a 5-meter circle to the planned target. Ultrasonic sensors have successfully detected targets in the external environment. With a very low cost and a simple algorithm, the vehicle has reached the targeted location. It was observed that the calculations and the test results matched. Key Words: Autonomous Drive, Firefly Algorithm, Sensors, Unmanned Ground Vehicle.
Heat transfer analysis of a solar absorber tube using 3D-printed swirl generators
In this study, novel 3D-printed short-length swirlers with various twist angles in the range of 0°-450° were inserted in a solar absorber tube heat exchanger to induce decaying swirl flow and investigate their thermo-hydraulic effects. Laminar air flow with Reynolds number in the range of 513 and 2054 was used. First, computational fluid dynamics (CFD) simulations were carried out by using the Finite Volume Method (FVM). Next, experimental analysis was conducted to validate numerical results. The results demonstrated that increasing the twist angle resulted in augmented thermal performance and increased friction factor. Similarly, the increase in Reynolds number caused an increase in Nusselt number. According to numerical results, the swirler with the highest twist angle of 450° employed together with the flow at Reynolds number of 2054 lead to the highest Nusselt number and friction factor enhancement ratios as 3.17 and 17.3, respectively. The highest Performance Evaluation Criteria (PEC) of 1.15 was observed at Reynolds 1031 using a swirler with 150° twist angle. Finally, the local analysis findings highlighted that flow near the swirler locations has higher tangential velocities indicating swirl-dominant flow and hence contributing to heat transfer enhancement remarkably.
Design and fmea analysis of horizontal balancing machine support
The structural design and structural analysis of support legs, or chassis, of horizontal balancing machines, i.e., decanter centrifuges, are addressed in the current thesis. Support structures are considered primary components that are inherent for providing system stability for vibration control and dynamic load absorption under operating states. Three support leg design configurations were designed and assessed with the Finite Element Method (FEM). Stress behavior, deformation properties, and values of natural frequency were compared, and numerical results experimentally confirmed. For preliminary stage of thesis, an initial setup in hollow rectangular shape form had been investigated. Afterwards, from preliminary setup, complex setup of pinned weld configuration had been resulted again, converted into stiffened setup with vertical stiffeners fitted around lengthwise of profile to get highest rigidity. Each setup had been made from S235JR structural steel, and fabrication afterwards using gas metal arc welding (GMAW) process. In-house jigs were used to get precise dimensions as well as suppress thermal deformation during welding. Based on quantitative outputs, it became evident that design reinforced with stiffeners minimized maximum deformation by around 19% compared to base case, raised first natural frequency by 13%, and improved critical buckling load carrying capacity in every direction. Maximum Von Mises stresses in all stages of load were less than yield strength of material, and experimental confirmation showed excellent correlation (R² > 0.95) between simulated FEM displacement and experiment displacement. These details were directly related to enhanced vibration resistance, load-carrying capacity, and long-term durability. Numerical and experimental investigation were used to arrive at advantages and limitations of every design, and optimal design parameters were computed. Improvement of mechanical reliability in decanter centrifuge machines using vibration-resistant, stable support leg designs as vibration outcome is regarded as main focus of present investigation. Keywords: Decanter centrifuge, support leg, chassis design, finite element method, structural analysis, vibration
Development of optical sorting machine
Since the late 90's, a boom in optics and photonics technology and its applications is observed. The optical sorter is an application of optics and photonics. Along with the development in Food, Mining and Waste/Recycle industry, the demand for such complex machines is also increased. Many big industries shifted from manual sorting of objects to take help from such mechanisms. In this study, the focus is put onto the optical or automated sorters and their working. The different components of a sorter are explained for different industries. The focused industry for the detailed working is Food industry because it shows more resemblance with other industries. Later in this study, a conceptualized model of an optical sorter is also presented which is designed in Solidworks software. This CAD model is designed in such a way that it can increase the efficiency and availability of such machines in the market. All the components are constructed and explained with details. Key Words: Automated, CAD, Optics, Photonics, Solidworks
Design of fixed wing unmanned aerial vehicle with predictive maintenance approach
In this study, the basic design of a fixed-wing unmanned aerial vehicle (UAV) and the predictive maintenance approach planned to be developed and sustained in line with the design were investigated. The geometry of the UAV was created using 3D design software. External flow analyses were performed on the designed geometry using the finite volume method. Based on the data obtained from the analyses, structural and layout design studies were carried out in accordance with the accepted external geometry. Subsequently, the mechanical behavior of the structural components was examined through appropriate analysis methods then software and a UAV design suitable for production and intended use was developed. According to obtained data UAV manufactured as a prototype using additive manufacturing application. Based on the results of the analyses, the placement of sensors and control equipment on the control surfaces and the aircraft body was proposed in terms of location. As a result, the structural and mechanical behaviors of the UAV under the loads expected throughout its service life were predicted then necessary evaluations were made. Depending on these evaluations, potential structural and mechanical problems on the components were predicted and the required maintenance types and intervals were reviewed from a predictive maintenance and maintainability perspective. Based on the conducted study and the obtained data, improvements in maintenance intervals, maintenance procedures, and maintenance personnel costs were projected in accordance with the expected operational behavior of the UAV throughout its service life.
Multi-objective optimization of ventilation hole on steel wheel
Objective: In this thesis, it is aimed to optimize the structural design of the ventilation hole in the steel wheel used in heavy commercial vehicles, which has successfully passed the radial fatigue and cornering fatigue tests, and to reduce the weight of the wheel so that it can meet the test values compared to the existing wheel. Material and Methods: In this study, 4 different ventilation types, von-mises stress on the disc, number of ventilations and rim weight were parameterized using ANSYS Mechanical. These 4 different ventilation type wheels are separately compared with the stress results on the disc and the rim weights of the wheel with ellipse ventilation. Response surface optimization was created to compare the values obtained from the Design of Experiment (DoE) using the Response Surface Optimization (RSO) module in Ansys Workbench. In order to find the optimized design from the response surface optimization, optimization was made using the Multi-Objective Genetic Algorithm (MOGA-II) method. Results: Maximum iteration number is 20, convergence stability percentage is 2%, maximum allowable Pareto percentage is 70%, initial sample number is optimized as 6000, the result is 1,3,3 and 3 candidate design points from round, slot, trapezoid and half-moon type vents was created, respectively. Conclusion: Compared to the current design of the ventilation type, characterized as half-moon from the obtained approaches, the optimized rim exhibited a reduced mass of 0.9 Kilograms by 2.05%, which indicates the effectiveness of the proposed method. Since a lighter result could not be obtained at the same stress values in the other three different ventilation types, a halfmoon type ventilation hole was preferred. Key Words: Design of Experiment, Multi-Objective Genetic Algorithm, Finite Element Method, Radial Fatigue Test, Response Surface Optimization
Design and optimization of propeller of submersible mixer for biogas plants
Objective: In this thesis, it is aimed to make hydraulic designs of axial mixers used in biogas plant fermenters using computer aided engineering calculation tools, to make pool tests with small scale models and finally to produce prototypes. Material and Methods: In this thesis, it is planned to improve the efficiency of the conventional axial biogas mixer by using computer aided engineering tools for design and optimization. To this end, a parametric design for blade geometry was used in conjunction with an open source CFD analysis software OpenFOAM to measure performance metrics (i.e. power, torque, thrust). Results: By maximizing the thrust-to-power ratio with the most efficient design, a fairly large parametric state space is created. Four different designs were reached from a series of design candidates residing in this space. By comparing these designs, the effects of design parameters on the results were evaluated. Conclusion: When the sensitivity results were compared in this study, it was determined that the factors affecting the blade efficiency the most were skew and pitch. Keywords: submersible mixer, propeller, parametric design, Open FOAM, Manure
Design and structural analysis of a 6-axis industrial robotic arm
The master's dissertation presents the conceptual design for a six-degree-of-freedom robotic arm for the automation of battery replacement in UAVs used in the agricultural sector. Due to their relatively short UAV flight times, battery changes are quite frequent, but such changes are detrimental to continuity in operations as well as overall productivity. The conceptual robotic-arm design was done in 3D using SolidWorks, while the robotic-arm's performance under real-life scenarios was determined using transient structural analyses done on Ansys. There is a custom-engineered cycloidal gear system in place at every robotic arm joint for achieving higher torque outputs, reduced backlash, and a compact spatial structure. The modular robot structure increases the robot's versatility for several UAV applications and allows for a range of operational needs. The material choice was made in order to provide an optimal balance between strength, weight, and manufacturability, and the resultant structure is made from an outer shell in the material grade aluminum A356 and internal structures made in 1.8550 steel. The end-effector is provided with a pneumatic-actuated gripper capable of gripping battery packs weighing as much as 12 kilograms. The inverse kinematics solutions, dynamic simulations, and transient load analyses provided findings that supported the structural soundness, small displacement, and high accuracy of the robotic arm. The findings all confirm the effectiveness of the system in realistic applications, making it a viable and novel methodology for battery replacement automation in unmanned aerial vehicles in agriculture.
Rollform prosesinde kesim sonrasi ağiz açikliği hatasinin incelenmesi
The roll forming process is defined as the step-by-step cold forming of a strip material into the desired cross-sectional geometry using forming rolls, referred to as stations. Roll forming is preferred in high-volume production due to its higher production speed and lower labor requirements compared to other cold forming methods. However, in low-volume production, it is less favored because of the long die setup times. During the roll forming process, the strip material undergoes plastic deformation during shaping, leading to the formation of residual stresses and resulting in permanent deformations within the material. These permanent deformations cause various geometric defects in the produced profiles, such as loss of straightness, bowing, twisting, waviness, and end flare after cutting. Profiles manufactured by roll forming are used in many sectors, including automotive, greenhouse, electrical-electronics, white goods, and solar energy systems. Particularly, end flare defects occurring after cutting significantly affect the functionality of profiles in assembly applications. Within the scope of this thesis, the formation mechanisms of end flare defects after cutting will be investigated; focusing on a U-section profile, the end flare defect will be analyzed using the finite element method, and practical solution methods aimed at minimizing the defect will be explored.