Mechanical Engineering / Makina Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4129
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Conference Object Citation - Scopus: 3A Continuously Variable Transmission System Designed for Human–robot Interfaces(Springer, 2021) Mobedi, Emir; Dede, Mehmet İsmet CanWithin a predefined limit, continuously variable transmission (CVT) systems can continuously vary the power transmission ratio. The transmission in CVTs is achieved via friction, belt or gear systems. If CVT designs can incorporate backdrivability, independent output position and impedance variation, shock absorbtion, and low mass and inertia, they can be employed in human–robot interfaces. Among various types of CVT designs, the two-cone drive CVT designs have a major drawback since the output torque and position cannot be changed independent of each other. The friction wheel used in this design does not have a holonomic motion capability and causes this inconvenience. In order to overcome this problem, a sphere is used in this work for the CVT design as the transmission element. In addition, it is stated in the literature that common CVT drive systems do not have the capability to be used in cyclic bidirectional motion. In the presented CVT design, a second sphere is added to the system with two springs from the lower part of the cones for pretension in order to solve the bidirectional transmission problem. In this paper, the working principle and conceptual design details of the novel two-cone CVT drive are presented. Experimental results showed that the novel CVT has the capacity to transmit bidirectional power with some accuracy. © 2021, Springer Nature Singapore Pte Ltd.Conference Object Energy and Exergy Analysis of a Roof-Mounted Photovoltaic System in Gebze-Turkey(Springer, 2024) Khalejan, Seyed Hamed Pour Rahmati; Cankurt, Tolga; Dede, Mehmet İsmet CanThis study investigates the electrical and thermal exergy, power conversion efficiency and exergy efficiency of a roof-mounted photovoltaic (PV) system considering environmental parameters such as solar irradiation, ambient temperature and wind speed over a year. The values of solar exergy and solar potential are obtained by taking into account the solar insolation. Experimental and theoretical results indicate that wind speed and surface temperature have significant effects on the thermal exergy and exergy efficiency of solar PV systems. The mean solar potential in the region was found to be 93%. In addition, the electrical exergy was varied from 9145 W to 40460 W and the thermal exergy of PV systems was varied from 1639 W to 6193 W. While the range of PV power conversion efficiency varies from 6.15% to 11.56% over a year, the range of exergy efficiency varies from 5.31% to 9.78%. © 2024, The Author(s), under exclusive license to Springer Nature Switzerland AG.Article Citation - WoS: 2Citation - Scopus: 4A Study on a Computationally Efficient Controller Design for a Surgical Robotic System(Springer, 2023) Ayit, Orhan; Dede, Mehmet İsmet CanThe control algorithms of the surgical robotic system using the robot’s dynamics produce a relatively high computational load on the processor. This paper develops a computationally efficient computed torque controller by using a simplified dynamic modeling method and implemented in a novel surgical robot experimentally. In addition, an independent joint controller is designed and implemented to compare the results of the computed torque controller. © 2023, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Conference Object Citation - Scopus: 2Experimental 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, GökhanIf 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.Conference Object Digital Twin of a Servo Driver of a Servo Motor as a First Step Towards a Digital Twin of a Robot Mechanism(Springer, 2022) Küçükoğlu, Sefa Furkan; Carbone, Giuseppe; Dede, Mehmet İsmet CanDigital Twin (DT) offers us to acquire actual system’s critical information and hence, it may be possible to develop and produce more suitable systems in terms of low energy consumption and effectiveness. In this way, responsible consumption and production systems can be designed and the system’s parameters can be tuned via DT. In this study, the model of a servomotor system that is used for industrial purposes is experimentally obtained. This study consists of two steps. In the first step, within the embedded control of the system, position and velocity control loops are deactivated. Then through the servo driver, currents with sinusoidal waveforms at various frequencies are applied to the servomotor. The resultant angular velocity of the motor is monitored and recorded. The amplitude of the current is kept constant during this study. The frequency of the current, however, is increased logarithmically. By using these data, a first-order transfer function (TF) is identified for the motor model. In the second step, all control loops are activated. Consequently, the total servomotor system could be represented in a digital environment. Furthermore, the static friction issue is overcome by using a Coulomb friction model with stiction effect. Finally, several experiments are conducted and then results are compared with the digital model of the servomotor system. The results clearly show that digital model can fairly represent the physical system.Conference Object Mechanisms, Transmissions and Applications(Springer, 2018) Dede, Mehmet İsmet Can; İtik, Mehmet; Lovasz, Erwin-Christian; Kiper, GökhanThis volume contains the proceedings of MeTrApp 2017, the 4th Conference on Mechanisms, Transmissions and Applications, that was held in Trabzon, Turkey, July 3-5, 2017. The topics treated in this volume are Mechanism Design, Parallel Manipulators, Control Applications, Mechanical Transmissions, Cam Mechanisms, and Dynamics of Machinery. The conference was organised by the IFToMM Technical Committees for “Linkages and Mechanical Controls” and “Gearing and Transmissions” under the patronage of the IFToMM and sponsorship of Karadeniz Technical University, Izmir Institute of Technology and IFToMM Turkey (MAKTED). The aim of the conference was to bring together researchers, scientists, industry experts and students to provide, in a friendly and stimulating environment, the opportunity to exchange know-how and promote collaboration in the field of Mechanism and Machine Science.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.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 2019Conference Object Conceptual Design of a 2-Dof Planar High-Speed Industrial Parallel Manipulator(Springer, 2019) Uzunoğlu, Emre; Özkahya, Merve; Paksoy, Erkan; Taner, Barış; Dede, Mehmet İsmet Can; Kiper, GökhanThis study focuses on conceptual design alternatives for a planar high-speed/high-precision manipulator in terms of mechanism structure, control strate-gy, and drive system selection. These concepts are investigated specifically for planar 5-bar based parallel linkages. An over-constrained 6-bar linkage with par-allelogram loops and its simply constrained version are selected for detailed de-sign. In addition, a model-based control strategy including a stiffness model is discussed for future studies. Alternative drive systems are evaluated. Finally a prototype is presented.Book 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.
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