Browsing by Author "Selvi, Özgün"

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Characterization of 3d Printed Conductive Flexible Materials for Soft Robotic Applications
(2024) Arslan, Ozan; Selvi, Özgün; Totuk, Onat
Soft robots composed of compliant and flexible materials can safely interact with humans and adapt to unstructured environments. However, integrating sensors, actuators, and control circuits into soft structures remains challenging. Additive manufacturing shows promise for fabricating soft robots with embedded electronics using conductive flexible composites. Nevertheless, there is still a limited understanding of the electromechanical behavior of 3D-printed conductive structures when subjected to the types of strains relevant to soft robotics applications. Optimized design requires characterizing the interplay between a soft component's changing shape and electrical properties during deformation. This study investigates the application of 3D printing technology to fabricate various geometries using a conductive, flexible material for soft robotic applications. The primary objective is to understand and characterize the behavior of differently shaped 3D-printed conductive materials under various mechanical stresses. Two distinct test setups are designed for conducting bending and tensile tests on the produced materials. Diverse geometries are printed using the conductive flexible material with desirable mechanical and electrical properties to employ tensile and bending tests. The experiments reveal a direct correlation between shape change and electrical resistance of the 3D printed materials, providing valuable insights into their adaptability for soft robotics. According to numerical results, honeycomb profiles are found to be the most linear and stable profile type. This research not only contributes to the field of flexible conductive materials but also lays the foundation for integrating these materials into future engineering designs, potentially enabling the development of highly responsive and adaptable devices for various industries.
Design and Production of Multi Material 3d Printer for Soft Robotic Structural Elements
(2021) Yetim, Murat; Çırnık, Samed Yiğit; Akan, Muhammed Enes; Tomaç, Temel; İlter, Hasan Fehmi; Selvi, Özgün
With the latest technology, the development and interest in soft robots have gained speed. Flexible robots are generally produced by the casting method. This traditional production method cannot meet the required quality and production speed. For this, it is aimed to solve the problem by accelerating the production of robots without decreasing the quality. The most successful method for solving this problem is 3D printers, which could print multiple materials. It was decided to be used multi-materials printing, and the system design was carried out. This study aims to design and produce a multi-material 3D printer capable of printing non-conductive and conductive rapidly curing silicone that can be used in soft robotics and medical simulators. The electrical conductivity was achieved by mixing silicone and graphite powder. The parts in the designed system are also obtained by the additive manufacturing method. Test pieces were printed using the produced 3D printer. Specific tests have been carried out on the produced parts. Technical data such as strength, elasticity, electrical conductivity have been obtained.
Citation - Scopus: 2
Effects of Earthquake Motion on Mechanism Operation: an Experimental Approach
(Levrotto and Bella, 2015) Selvi, Ö.; Selvi, Özgün; Ceccarelli, M.; Aytar, E.B.; Makine Mühendisliği
This paper presents an experimental characterization of the effects of earthquakes on the operation of mechanical systems with the help of CaPaMan (Cassino Parallel Manipulator), which is a 3 DOF robot that can fairly well simulate 3D earthquake motion. The sensitivity of operation characteristics of machinery to earthquake disturbance is identified and characterized through experimental tests. Experimental tests have been carried out by using a slider-crank linkage, a small car model, and LARM Hand as test-bed mechanisms that have been sensored with proper acceleration or force sensors. Results are reported and discussed to describe the effects of earthquake motion on the characteristics of mechanism operation as a service application of the robotic CaPaMan system.
Kinematic Analysis Of A 5 Dof Overconstrained Manipulator For Rehabilitation Of Upper Extremite
(2015) Selvi, Özgün; Al-dulaimi, Hasan
This study deals with one of the applications of parallel manipulator as a rehabilitation robot. This device is an over –constrained parallel manipulator 5 degree of freedom with 3 legs. This manipulator consists of a moving platform which is connected to a fixed base via three legs. Each leg is made of RRR(RR) (revolute) joints where the first three joint in all legs are parallel and the recent two joint are intersecting .Inverse kinematics of this device is solved by dividing manipulator into two sub-manipulators with the help of three imaginary joints placed at the intersection of platform joints with a direction parallel to base joints.
Strengthening Effect of Flooding in 3d Printed Porous Soft Robotics Scaffolds
(2021) Arslan, Ozan; Selvi, Özgün; Mıstıkoglu, Selçuk; Totuk, Onat
This study aims to design and 3D print porous elements for soft robotic applications and test the stiffness changes when the cavities are filled with liquids. When an elastic element has porous scaffolds, the stiffness can be controlled by filling the cavities with a liquid. A gyroid structure is selected for the design and evaluation of the characteristics of elements. The stiffness of the element in both non-filled and liquid-filled modes is analyzed using FEM simulation Software in two modes where simple support with central loading and compressive uniform loading. A porous test structure is created and tested in these modes for observation of the stiffness change. Employing an FDM printer in this project enabled us to make our thoughts to reality. The results show that liquid-filling can be used as a stiffening method for porous scaffolds in soft robotic applications.
Üç Serbestlik Dereceli Paralel Rehabilitasyon Eyleyicinin Ateş Böceği Algoritması Kullanılarak Boyutsal Olarak Eniyilemesi
(2016) Selvi, Özgün; Yavuz, Samet
Bu çalışma, insan bilek eklemi rehabilitasyonunda kullanılacak üç serbestlik derecesine sahip üç bacaklı küresel bir paralel eyleyicinin belirli bir çalışma uzayında çalışmasını sağlayacak boyutsal parametrelerin tespitini amaçlamaktadır. Bahsi geçen eyleyicinin son-elemanı insan bilek ekleminin üç serbestlik derecesini kapsamaktadır. Eyleyicinin her bacağı iki küresel uzva sahiptir ve tüm eklem eksenleri ortak bir noktada kesişmektedir. Eniyileme algoritmasında kullanılmak üzere eyleyicinin ters kinematik denklemleri çözülmüş Jacobi matrisi elde edilmiştir. Daha sonra ters kinematik denklemlerinden ve Jacobi matrisinden elde edilen kısıtlar ateş böceği algoritmasında kullanılarak belirli çalışma alanı için boyutsal eniyileme gerçekleştirilmiştir. Son olarak bu boyutsal parametrelerle bilek hareketleri benzetimlenerek çalışma alanı testi gerçekleştirilmiştir.