Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Article Citation - WoS: 10Citation - Scopus: 10Stiffness Modeling of a 2-Dof Over-Constrained Planar Parallel Mechanism(Elsevier, 2023) Görgülü, İbrahimcan; Dede, Mehmet İsmet Can; Kiper, GökhanStiffness 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 Haptik Cihaz için İyileştirilmiş Performansa Sahip Robot Tasarımı(Özyeğin Üniversitesi, 2019) Görgülü, İbrahimcan; Karabulut, Mehmet Görkem; Sekendiz, Veysel; Kiper, Gökhan; Dede, Mehmet İsmet CanBu bildiri daha önce tasarlanmış bir kinestetik haptik cihazın tasarımının iyileştirilmesi için yapılan çalışmayı içermektedir. Bahsi geçen iyileştirme cihazın empedans aralığının genişletilmesine yöneliktir. Bu başarım kıstasında iyileştirme için yapılan mekanizma eniyileme, pasif dengeleme, konstrüksiyonel tasarımda iyileştirme ve eyleyici sistem tasarımı çalışmaları yürütülmüş ve bu bildiride sunulmuştur.Article Citation - WoS: 3Citation - Scopus: 3Experimental Structural Stiffness Analysis of a Surgical Haptic Master Device Manipulator(American Society of Mechanical Engineers, 2021) Görgülü, İbrahimcan; Dede, Mehmet İsmet Can; Carbone, GiuseppeThis paper deals with haptic devices for master-slave telesurgical applications. Namely, a stiffness model fitting methodology and its fine-tuning are proposed based on experimental results. In particular, the proposed procedure is based on virtual joint structural stiffness modeling to be applied in time-efficient compliance compensation strategies. A specific case study is discussed by referring to the HISS haptic device that has been developed and built at Izmir Institute of Technology. Two different experimental setups are designed for stiffness evaluation tests. Experimental results are discussed to demonstrate their implementation in the proposed methodology for the fine-tuning of stiffness model.Book Part An Experimental Setup and Procedure for Stiffness Evaluation of Robot Manipulators(Springer, 2021) Görgülü, İbrahimcan; Paksoy, Erkan; Carbone, Giuseppe; Dede, Mehmet İsmet CanIn this paper, an experimental test setup for stiffness evaluation of a spatial parallel mechanism is introduced. The parallel mechanism used in this study is R-CUBE mechanism. In the test setup, a highly rigid gantry-type manipulator’s end-effector is coupled with the R-CUBE’s mobile platform. As the gantry manipulator is actuated the resultant reaction forces/moments are measured via a force\torque sensor. Subsequently, compliant displacements of R-CUBE are measured by using a coordinate measuring machine. The obtained results are presented and discussed in this paper. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - WoS: 11Citation - Scopus: 11A New Stiffness Performance Index: Volumetric Isotropy Index(MDPI, 2019) Görgülü, İbrahimcan; Dede, Mehmet İsmet CanA new index for a precise calculation of a manipulator's stiffness isotropy is introduced. The proposed index is compared with the conventionally used stiffness isotropy index by making use of the investigation on R-CUBE manipulator. The proposed index is shown to produce relatively more precise results from which a higher number of isotropic poses are detected.Article Citation - WoS: 24Citation - Scopus: 30Time Efficient Stiffness Model Computation for a Parallel Haptic Mechanism Via the Virtual Joint Method(Elsevier, 2020) Carbone, Giuseppe; Görgülü, İbrahimcan; Dede, Mehmet İsmet CanHaptic devices are used for displaying a range of mechanical impedance values to the user. This impedance is regulated by a real-time control loop depending on the position information of the end-effector, which is usually acquired indirectly by using forward kinematics equations. Nevertheless, the kinematic model is insufficient to obtain accurate values if there are non-negligible compliant displacements. This gives a strong motivation for implementing a real-time stiffness model in the haptic control loop for improving its accuracy. Additionally, stiffness performance indices can be used at the design stage for enhancing the haptic devices impedance range within optimal design procedures. Fast solutions of a stiffness model are required for a real-time control as well as for decreasing the optimization time during a design process with a trade-off between accuracy and computational costs. In this study, we propose a computation time-efficient stiffness analysis of a parallel haptic device mechanism. The accuracy and computational costs of the proposed model are calculated and compared with a model that is obtained via a finite element method to demonstrate the effectiveness of the proposed approach with the desired real-time and accuracy performance. (C) 2019 Elsevier Ltd. All rights reserved.Book Part Citation - Scopus: 2Computation Time Efficient Stiffness Analysis of the Modified R-Cube Mechanism(Springer, 2019) Görgülü, İbrahimcan; Dede, Mehmet İsmet CanParallel manipulators are known to be more stiff than the serial manipulators. However, modeling the stiffness for parallel manipulators are difficult compared to serial manipulators due to the constrained structure and passive joints. In addition, computation of the stiffness model for parallel manipulators are exhausting since it requires an iterative solution algorithm due requirement of force-position convergence of all serial chains connecting to the same mobile platform. Direct solutions are faster however, they lack in accuracy. In this study, direct solution is preferred for real-time application and analytic stiffness model of the modified R-CUBE mechanism is obtained by using Virtual Joint Method (VJM). The finite element (FE) model is constructed and simulated to validate the analytical model. Then, a combination of external wrenches $$\pm 5$$ N in various directions are applied on the mobile platform in both FE and VJM in some critical poses. Finally, the computed numerical results are listed and compared along with their computation times. © Springer Nature Switzerland AG 2019Book Part Citation - Scopus: 5An Experimental Test Procedure for Validation of Stiffness Model: a Case Study for R-Cube Parallel Mechanism(Springer, 2019) Görgülü, İbrahimcan; Dede, Mehmet İsmet Can; Carbone, GiuseppeHaptic device manipulators are used for generating haptic feedback. This feedback is composed of force which is regulated with respect to motion information. Accurate generation of the feedback requires exact position acquisition of the end-effector. Due to the compliant bodies of a manipulator, a stiffness model is needed to predict this position. Previously, Virtual Joint Method was adopted to obtain the stiffness model of an R-CUBE parallel haptic mechanism. In this paper, experimental test setup and experimental procedure are described for validating this stiffness model, its engineering feasibility and soundness of the proposed model.Conference Object Citation - Scopus: 1Structural Compliance Effects on the Accuracy and Safety of a R-Cube Haptic Device(Springer Verlag, 2019) Carbone, Giuseppe; Acinapura, Antonio; Mundo, Domenico; Görgülü, İbrahimcan; Dede, Mehmet İsmet CanThis paper addresses the contribution of structural compliance on stiffness and safety of a R-CUBE Haptic Device. Structural compliance is determined in several poses via FEM analysis and addressed by referring to local and global indices of performance. Results are also compared with evidences from experimental tests. Comparison of numerical and experimental data allows to identify and separate the contributions to the overall compliance that are due to the structural stiffness, and other contributions such as joint clearance, pose and loading conditions.Conference Object Manipulator Design for a Haptic System With Improved Performance(Springer, 2021) Sekendiz, Veysel; Görgülü, İbrahimcan; Karabulut, Mehmet Görkem; Kiper, Gökhan; Dede, Mehmet İsmet CanThis paper presents the work carried out to improve the design of an existing kinesthetic haptic device. The proposed improvement is designated for enhancing this device’s impedance width which is a common metric in performance evaluation of haptic devices. In this study, kinematic design optimization, static balancing, constructional design enhancement and actuation system design studies are presented.