Mechanical Engineering / Makina Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/4129

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2010 - 2019522020 - 202523

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Access type: Open accessAuthor: search.filters.author.Kiper, Gökhan

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  • Conference Object
    Redundancy resolution options for the twin-it-romans robotic hybrid manufacturing system
    (Springer Science and Business Media B.V., 2025) Gündüz, G.M.; Dede, Mehmet İsmet Can; Kiper, Gökhan; Schmitz, M.; Corves, B.
    The Twinnig Iztech in Robotics Manufacturing System (TWIN-IT-ROMANS) project funded by EU Horizon -Widera-2023-Access-02-01 aims to develop a hybrid manufacturing system that can perform additive and subtractive manufacturing processes and inline quality control using a robotic system. The system will incorporate a 6-degree-of-freedom robot arm and a positioner with 2-degree-of-freedom, which will operate synchronously. This manipulation system is to be designed for performing different manufacturing operations with different degrees-of-freedom requirements. In order to reveal alternative trajectory planning scenarios for this system, this paper presents an initial review of redundancy resolution approaches for kinematically redundant robotic manipulators. First, the four main approaches for redundancy resolution techniques are introduced. Then main studies on energy minimization and stiffness maximization for kinematically redundant robotic manipulators are reviewed. Similar or new approaches are planned to be generated and implemented for the redundant system for hybrid manufacturing. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2025.
  • Conference Object
    Citation - Scopus: 3
    Four-bar function generation using excel solver
    (Springer, 2023) Söylemez, Eres; Kiper, Gökhan
    The Chapter presents a simple and efficient way of approximating a function with a four-bar mechanism using four or five design parameters including one or both of the initial crank angles. The method only involves solution of linear set of equations and evaluating determinants, whereas nonlinear equations are numerically solved using a simple program such as Excel. So, the method is easy to explain and can be taught in an undergraduate course along with the wellknown linear three precision point synthesis problem. Precision point synthesis, order synthesis, mixed order synthesis, least squares approximation and extreme point synthesis can all be treated using the same method. The proposed method is illustrated with numerical examples for all mentioned synthesis problems and shown to be quite efficient with very low amount of structural error values.
  • Article
    Citation - WoS: 10
    Citation - Scopus: 10
    Stiffness Modeling of a 2-Dof Over-Constrained Planar Parallel Mechanism
    (Elsevier, 2023) Görgülü, İbrahimcan; Dede, Mehmet İsmet Can; Kiper, Gökhan
    Stiffness model acquisition of over-constrained parallel mechanisms is relatively difficult since they have more than necessary kinematic loops. In this study, a stiffness modeling solution for over-constrained parallel mechanisms is proposed while considering the computational cost efficiency. Three contributions of the paper are: (1) Presenting the stiffness modeling procedure for serially connected closed-loop structures by using the Virtual Joint Method (2) Considering the effect of dynamic auxiliary forces and dynamic external forces on the mobile platform's deflection and achieving a direct solution by using superposition principle (3) A model fitting procedure for modifying the stiffness coefficients to comply with the experimental data. A 2 degrees-of-freedom over-constrained parallel mechanism is investigated as a case study. However, the proposed stiffness model is 6-DoF since compliant deflections occur in any direction. A finite element analysis and an experimental study verify the model's results.
  • Conference Object
    Citation - Scopus: 3
    Design and Balancing of a Novel 2r1t Manipulator With Remote Center of Motion
    (Springer, 2023) Yılmaz, Tuğrul; Kiper, Gökhan
    The paper presents a novel manipulator design to be used as an endoscope holder for endonasal skull base surgeries. The manipulator should provide two rotational and one translational motions for the endoscope, where it should be able to be oriented about and slide along the tip of the nostril of a patient as a pivot point. First, suitable manipulators with remote center motion are investigated. Manipulators with serial and hybrid kinematic structure and redundant manipulators with a passive joint are examined. A serial manipulator with a circular arc as the second rotation axis is chosen for the detailed design. The novelty of the kinematic structure of the manipulator is that the end-effector heave motion is achieved in a tangential direction to the circular arc. The constructional design and counter-mass balancing solution for the manipulator are presented. The total assembly mass is 11.6 kg for navigating an endoscope of 0.44 kg mass.
  • Research Project
    Yeni alt-bileşenlerinin geliştirilmesi ile iyileştirilmiş başarımlı bir haptik sistem tasarımı (HİSS)
    (2019) Dede, Mehmet İsmet Can; Kiper, Gökhan
    Bir teleoperasyon sistemi kullanıcı tarafındaki ana sistem, görev yerindeki bagımlı sistem ve bu iki sistem arasındaki iletisim altyapısından olusmaktadır. Genellikle ana sistem görev yerinden uzaktadır ve kullanıcı ana sistemi kullanarak gönderdigi komutlar ile bagımlı sistemi kullanarak görevi gerçeklestirir. Söz konusu komutlar sıklıkla hareket komutlarıdır ve ana sistem kullanıcıdan bu hareket komutlarını toplamakla yükümlüdür. Görevin ihtiyacına göre söz konusu hareket komutları kullanıcının genellikle el hareketlerinden ve bazen de kullanıcının ayak, bacak, göz veya tüm vücut hareketlerinin de algılanması ile toplanabilir. Eger teleoperasyon sisteminde bagımlı sistemin görev yeri ile olan fiziksel etkilesim bilgisi kuvvet geri-beslemesi olarak ana sisteme gönderilecek ise ana sistemin geri iletilen bu kuvvet bilgisini kullanıcıya iletmesi gereklidir. Hem kullanıcının arzu edilen uzuv hareketlerini toplayan hem de kullanıcıya kuvvet iletimini saglayan cihazlara kinestetik haptik cihazlar denir. Bu projede, masaüstü haptik cihaz teknolojisinde yeni mekanizma, yeni alt-bilesenler ve model iyilestirmeleri üzerinde çalısılması ile uzaktan ameliyat sistemleri gibi hassas çalısmalarda kullanılabilecek cihaz ve alt-bilesenlerinin gelistirilmesi amaçlanmıstır. Proje kapsamında (i) manyeto-reolojik (MR) sıvısı ile gelistirilen eyleyici sistemde yapısma sorununa çözüm getiren bir eyleyici sistem gelistirilmistir (ii) çoklu hedefli eniyileme ile haptik cihaz mekanizmasının uzuvlarının fiziksel özellikleri belirlenmistir (iii) pasif dengelenme tasarımları R-CUBE mekanizması üzerinde hayata geçirilmistir (iv) aktarma oranı sürekli degistirilebilir yapıda bir aktarma organı tasarımı mafsalların direngenliginin ayarlanması için gelistirilmistir (v) haptik cihaza özgü son üründe kullanılabilecek kontrol kartı gelistirilmistir. Bahsi geçen kapsamda yapılan çalısmalar neticesinde literatüre yeni bir MR sıvısı tabanlı eyleyici sistemi, yeni bir aktarma organı ve yeni bir direngenlik basarım ölçütü kazandırılmıstır.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Design of Demountable Reciprocal Frames With New Geometric Properties
    (Int. Association for Shell and Spatial Structures, 2022) Özen, Gülçin; Kiper, Gökhan; Korkmaz, Koray
    This study aims to develop missing geometric knowledge for demountable reciprocal frames (RF). While designing a demountable RF, one should know the initial, in-process and final form of the RF. These processes require some specific geometric knowledge. There are some deficiencies about geometric properties in the previous studies about demountable RFs. In this study, the positions and the orientations of the nexors are found by using the Denavit-Hartenberg parameters. This information gives where the joints are placed, how they are oriented and take position according to one another. Besides, the influence of engagement length on the fan height and the base edge are analyzed. Thereby one will be able to find out how much space the RF covers with the known base edge. With the geometric knowledge obtained from this study, demountable RFs having different engagement lengths can be produced with the same nexors.
  • Article
    A Novel Design Method of Deployable Semi-Regular Tessellated Surfaces With Plano-Spherical Units
    (Int. Association for Shell and Spatial Structures, 2022) Maral, Mesude Oraj; Korkmaz, Koray; Kiper, Gökhan
    The design of movable systems gives an opportunity to create transformable designs which respond to the environmental, functional, cultural, and aesthetical needs of today's architecture. This paper proposes a method for designing a family of deployable structures which can be applied to semi-regular tessellated planar surfaces such as roofs, walls, and shading devices. The generated modular approach and adaptability provides a wide usage area and various combinations for these designs. The regular convex polygon modules are designed as a network of the triangular units. The triangular unit is designed using Bennett's overconstrained plano-spherical linkage topology. The polygonal modules are assembled to each other in one-uniform semi-regular tessellations. The assembly of adjacent regular convex polygons in each tessellation is examined to find a proper solution for no collision during deployment and to properly fit a surface without any gaps or overlaps in the deployed position. The assembly method for creating 1-DoF deployable surfaces and mobility calculations for a unit, the polygonal modules, and the assemblies are computed, and motion studies are demonstrated with CAD models and exemplified for a square module for motion tests in a prototype.
  • Conference Object
    Citation - Scopus: 2
    Experimental Compliance Matrix Derivation for Enhancing Trajectory Tracking of a 2-Dof High-Accelerated Over-Constrained Mechanism
    (Springer, 2022) Paksoy, Erkan; Dede, Mehmet İsmet Can; Kiper, Gökhan
    If the positioning accuracy of the end-effector of a robot has high priority, compliance characteristics of the elements of its mechanism should be considered. Due to the external loading on the robot, the dimensions of the elements change and this leads to positioning errors for the end-effector. In this paper, an experimental test setup and an experimental procedure are described to derive the compliance characteristics of a planar 2-degree-of-freedom mechanism.
  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Gravity Compensation of a 2r1t Mechanism With Remote Center of Motion for Minimally Invasive Transnasal Surgery Applications [article]
    (Cambridge University Press, 2023) Aldanmaz, Ataol Behram; Ayit, Orhan; Kiper, Gökhan; Dede, Mehmet İsmet Can
    This work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center of motion. A previously developed balancing solution is modified and applied to a prototype and test results are presented. The mechanism is an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, the endoscope is inserted through a nostril of the patient through a natural path to the pituitary gland. During the surgery, it is vital for the manipulator to be statically balanced so that in case of a motor failure, the patient is protected against any harmful motion of the endoscope. Additionally, static balancing takes the gravitational load from the actuators and hence facilitates the control of the mechanism. The mechanism is a 2URRR-URR type parallel manipulator with three legs. The payload mass is distributed to the legs on the sides. By using counter-masses for two links of each leg, the center of mass of each leg is lumped on the proximal link which simplifies the problem to balancing of a two degree-of-freedom inverted pendulum. The two proximal links with the lumped mass are statically balanced via springs. Dynamic simulations indicate that when the mechanism is statically balanced, generated actuator torques are reduced by 93.5%. Finally, the balancing solution is implemented on the prototype of the manipulator. The tests indicate that the manipulator is statically balanced within its task space when the actuators are disconnected. When the actuators are connected, the torque requirements decrease by about 37.8% with balancing.
  • Conference Object
    Krank Açıları Verilen Üç Konum ve Bir Ölü Konum için Dört-çubuk Mekanizmasının İşlev Sentezi
    (Makina Teorisi Derneği, 2021) Kadak, Tarık; Kiper, Gökhan
    Dört-çubuk mekanizmasının işlev sentezi, krank açıları ilişkisi ve ölü konum sentezinin karışık bir problemi olarak formüle edilebilir. Bu sentez probleminde, üç konum için krank ve sarkaç açıları ve dördüncü bir konum olarak bir ölü konumun krank açısı girdi olarak alınmıştır. Yazılan denklemler ve değişken elemeleri sonucunda herhangi bir nümerik yöntem ile çözülebilen tek değişkenli bir doğrusal olmayan denklem elde edilmiştir. Tek değişkenin hızlı çözümü ile mekanizmanın uzuv boyları bulunabilmektedir. Parametrik model kullanılarak Excel’de sayısal çözüm sayfası hazırlanmıştır. Sayısal örnekler genelde iki gerçel çözümün olduğunu göstermektedir.