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Öğe 5 Eksenli Manipülatörün Eklem Uzayında Yörünge Planlaması(2017) Uzuner, Sabri; Akkuş, Nihat; Toz, MetinBu çalışmada eğitim amaçlı kullanılmak üzere dönel eklemlere sahip 5 Serbestlik Dereceli (SD) bir seri robot manipülatörü gerçekleştirilmiştir. Robot 150 gr taşıma kapasiteli ve eklem hareketleri rahat, sürtünmesiz ve titreşimsiz olarak hareket edebilmesine imkân sağlayacak özelliklerde,radyo kontrollü R/C Servo motorlar kullanılmıştır. Eklem uzayında yörünge planlaması yapabilmek için robotun ters kinematik problemi çözülmüş ve yörünge planlaması üçüncü dereceden bir polinom kullanılarak gerçekleştirilmiştir. Tasarlanan 5 eksenli manipülatörün kullanıcı tarafından rahat ve basit bir şekilde kullanılması amacıyla Visual BASIC programında görsel bir arayüz hazırlanmıştır. Son olarak geliştirilen mekanizmanın öğrenciler tarafından yapılan robotlarla ilgili uygulamalarda başarıyla kullanıldığı gözlemlenmiştirÖğe 5-DOF serial robot manipulator design, application and inverse kinematic solution through analytical method and simple search technique(2020) Uzuner, Sabri; Akkus, Nihat; Toz, MetinIn this study a five Degrees of Freedom (DOF) serial robot manipulatorwas designed and implemented. The inverse kinematics problem, whichhas not exact analytical solution (only one inverse kinematic solutionfor a predefined end effector position in three dimensional space), of therobot mechanism was solved by using the combination of the analyticalmethod and a simple search method. In order to use the proposedmethod in real-time applications, the method is designed so that it canbe used to solve the inverse kinematics problem for the next point of theend-effector while the mechanism is working. Moreover, so that tocontrol the implemented mechanism, a user interface program waswritten by using Visual Basic programming language. Finally, theproposed inverse kinematic solution method was tested on two differenttrajectories, an arc shaped trajectory that composed of 58 points and alinear trajectory divided into 29 points. The obtained results revealedthat the proposed method can be used successfully in solving the inversekinematic problem of the designed mechanism.Öğe AISI 304 Paslanmaz Çelikte Geliştirilmiş Yüzey Kalitesi ve Azaltılmış Kerf Genişliği için Lazer Kesim Parametrelerinin optimizasyonu(2023) Nas, Engin; Uzuner, SabriBu çalışmada, yaygın olarak kullanılan bir lazer kesme makinesi kullanılarak AISI 304 paslanmaz çeliğin kesilmesi üzerine deneysel ve istatistiksel analizler gerçekleştirdik. Kesme parametreleri olarak üç farklı gaz basıncı 5.1, 6.4 ve 8 bar) , üç farklı kesme hızı (2048, 2560 ve 3200 mm/dak), sabit odak noktası (-4 mm), sabit frekans (5000 Hz) ve sabit gaz (Azot) kullanılmıştır. Yapılan çalışmanın sonucunda Bütün basınç değerlerinde kesme hızı arttıkça yüzey pürüzlülük değerinin azaldığı, bütün kesme hızı değerlerinde basınç arttıkça yüzey pürüzlülük değerinin arttığı görülmüştür. Kesme hızının artması ve gaz basıncının azalması ile üst ve alt kerf genişliğinin azaldığı, gaz basıncının artması ve kesme hızının azalması ile üst ve alt kerf genişliğinin arttığı belirlenmiştir. Taguchi analizi sonucunda sinyal/gürültü oranları incelendiğinde optimum kesme parametresinin basınç için Seviye 1 (5.1 bar) ve kesme hızı için Seviye 3 (3200 mm/dak.) olarak hesaplanmıştır. Varyans sonuçları incelendiğinde basınç ve kesme hızı faktörlerinden yüzey pürüzlülüğü değerine etki eden önemli parametrenin %70.74 ile kesme hızı olarak oluştuğu tespit edilmiştir.Öğe Changes in Knee Joint Mechanics After Medial Meniscectomy Determined With a Poromechanical Model(Asme, 2020) Uzuner, Sabri; Li, LePing; Kucuk, Serdar; Memisoglu, KayaThe menisci play a vital role in the mechanical function of knee joint. Unfortunately, meniscal tears often occur. Meniscectomy is a surgical treatment for meniscal tears; however, mechanical changes in the knee joint after meniscectomy is a risk factor to osteoarthritis (OA). The objective of this study was to investigate the altered cartilage mechanics of different medial meniscectomies using a poromechanical model of the knee joint. The cartilaginous tissues were modeled as nonlinear fibril-reinforced porous materials with full saturation. The ligaments were considered as anisotropic hyperelastic and reinforced by a fibrillar collagen network. A compressive creep load of body weight was applied in full extension of the right knee during 200s standing. Four finite element models were developed to simulate different meniscectomies of the joint using the intact model as the reference for comparison. The modeling results showed a higher load support in the lateral than medial compartment in the intact joint, and the difference in the load share between the compartments was augmented with medial meniscectomy. Similarly, the contact and fluid pressures were higher in the lateral compartment. On the other hand, the medial meniscus in the normal joint experienced more loading than the lateral one. Furthermore, the contact pressure distribution changed with creep, resulting in a load transfer between cartilage and meniscus within each compartment while the total load born by the compartment remained unchanged. This study has quantified the altered contact mechanics on the type and size of meniscectomies, which may be used to understand meniscal tear or support surgical decisions.Öğe Dual fluoroscopic evaluation of human tibiofemoral joint kinematics during a prolonged standing: A pilot study(Elsevier - Division Reed Elsevier India Pvt Ltd, 2019) Uzuner, Sabri; Rodriguez, Marcel L.; Li, Leping; Küçük, SerdarA complete knowledge of tibiofemoral joint kinematics is essential for understanding the function of the healthy and pathological joint. The objective of the present study was to establish a dual fluoroscopic measurement protocol and a data processing approach for the creep response of the knee joint in order to further evaluate the mechanical properties of articular cartilage and meniscus in vivo. A computational approach was developed for the determination of 3D translations and rotations of the joints of young participants with no history of injury using dual fluoroscopic images of loaded joints and joint geometry reconstructed from magnetic resonance imaging of the unloaded joints. High-resolution X-ray images were obtained for the distal femur and proximal tibia during 10-min standing when approximately 3/4 body weight was slowly applied to the right leg and then kept constant for the rest duration of the test. Anatomic coordinate systems were established for the 3D models of distal femur and proximal tibia. Translations and rotations of the joint as functions of time were then evaluated using the X-ray images and these coordinate systems with the JointTrack software. The displacements in the proximal-distal direction obtained from two participants were consistent, showing a substantial increase in the initial phase when joint loading increased from nil to 3/4 body weight and a continued small increase over time while the joint loading remained constant. The maximum anterior-posterior translations during 10-min standing were approximately 4 mm for both participants, although one showed better stability than the other. In conclusion, a creep loading protocol of the knee joint can be reasonably established for in vivo conditions and evaluated with the image-based computational approach. (C) 2019 Karabuk University. Publishing services by Elsevier B.V.Öğe Kıkırdağın Çok Yönlü Dinamiklerinin İncelenmesi: Karşılaştırmalı Modelleme Çalışması(Duzce University, 2024) Uzuner, SabriKıkırdak sayısal modelleri, kıkırdak mekaniği, hastalık ilerlemesi ve klinik müdahalelerin geliştirilmesi konusundaki anlayışımızı ilerletmede hayati bir rol oynamaktadır. Bu çalışmanın amacı, farklı matematiksel modellerin zaman içinde kıkırdak mekanik davranışı üzerindeki etkisini araştırmaktır. Üç senaryoda karşılaştırmalı bir analiz yapılmıştır: tek fazlı model, bifazik model ve fibril takviyeli poroelastik model. Kıkırdağın zaman içinde nasıl davrandığını anlamak için 1000 saniyelik bir rampa gevşeme deplasmanı uygulanmıştır. Bulgular, tek fazlı modelin kıkırdağın zamana bağlı özelliklerini yakalamakta yetersiz kaldığını ortaya koymaktadır. Buna karşılık, kıkırdak modeline sıvı ve kolajen fibrillerin dahil edilmesi kıkırdak direncini önemli ölçüde artırmakta ve kıkırdağın doğrusal olmayan bir şekilde davranmasını sağlamaktadır. Burada sunulan sonuçlar, sıvı basıncı ve fibril takviyesi arasındaki karmaşık etkileşime ışık tutarak, kıkırdağın basınç yükleri altındaki dinamik davranışının daha derin ve daha bütünsel bir şekilde anlaşılmasına önemli bir katkı sağlamaktadır.Öğe Numerical analysis of a poroelastic cartilage model: Investigating the influence of changing material properties in osteoarthritis(Sage Publications Ltd, 2024) Uzuner, SabriSeveral changes occur in both the cartilage's material properties and anatomical structure as osteoarthritis progresses. Unlike most numerical studies that solely consider individual changes, our study aimed to understand the impact on cartilage mechanics by considering the combined effect of material properties and cartilage thickness varied with osteoarthritis progression. In total, 3 three-dimensional finite element models, representing the intact, early, and late osteoarthritis conditions, were developed to simulate a load-bearing area in the knee. The articular cartilage was modelled as fluid-saturated linear biphasic poroelastic to incorporate solid-fluid interaction. All models underwent prolonged creep (50 N) and relaxation (0.3 mm) analyses for 600 s. In the early stage of osteoarthritis, the tibial cartilage demonstrated an overall stiffer behaviour attributed to cartilage swelling despite decreased stiffness at the material level. On the other hand, in the late stage of osteoarthritis, the decrease in cartilage thickness led to increased knee deformation. Additionally, increased permeability resulted in accelerated fluid exudation across all osteoarthritis models, and the elevation in void ratio further intensified fluid pressure within the cartilage to a higher magnitude. Furthermore, these changes collectively influenced both the magnitude and distribution of the outcomes. A holistic understanding of the material properties altered in osteoarthritis may contribute to a better understanding of the mechanical performance of cartilage during disease progression.Öğe RFID Cartesian Smart Parking Lot System(Kastamonu University, 2023) Uzuner, Sabri; Çelebi, Fatih MertIn recent years, smart products in different fields that have come to the market continue to exist and increase. Smart products, which we hear about in every sector, allow us to make life easier, save time, and even allows us to protect nature. In this study, the smart parking lot system aims to provide security, save space, save time, and reduce the carbon emitted while searching for a parking space with the vehicle. In the present study, Arduino MEGA 2560 was used as the controller, DC motor with reducer to provide movement, encoder to count the steps of the moving motors, servo motor to place the cars on the shelves, mfrc522 card reader to read RFID cards, 20x4 LCD screen for information and 12V DC adapter to provide the power required by the system. The car park has 3 rows and 4 columns and 12 parking spaces. The vehicle arriving at the car park is parked in the car park by reading any RFID (13.56MHz) card. If there is no free space, the warning "There is no space in the parking lot!" is given. In the realized system, integrating RFID security standards into parking lot automation may provide advantages in terms of security and time.Öğe Trajectory Planning of a 5-DOF Serial Robot Manipulator in Joint-Space(Gazi Univ, 2017) Uzuner, Sabri; Akkuş, Nihat; Toz, MetinIn this study, a five Degrees of Freedom (DOF) serial robot manipulator with revolute joints was designed and realized to be used for educational purposes. The robot has 150 gr payload and the motions of the joints were provided by using radio controlled R/C servo motors with smooth and vibration-free movement. In order to perform the trajectory planning in the joint space the inverse kinematics problem of the robot was solved and a third order polynomial was used for the trajectory planning. So as to present a simple and efficient way to the user for controlling the robot, a visual user interface was also designed by utilizing Visual Basic Programming Language. Finally, it was observed that the designed mechanism has been successfully used by the students for the projects involving robots.
