Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
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Article A Hybrid Control Scheme for Backdriving a Surgical Robot About a Pivot Point(MDPI, 2025) Dede, Mehmet İsmet Can; Kurt, A. N. Olcay; Deniz, Mehmet Firat; 01. Izmir Institute of Technology; 03. Faculty of Engineering; 03.10. Department of Mechanical EngineeringAn incision point acts as the pivot point when a minimally invasive surgery procedure is applied. The assistive robot arms employed for such operation must have the capability to perform a remote center of motion (RCM) at this pivot point. Other than designing RCM mechanisms, a common practice is to use a readily available spatial serial robot arm and control it to impose this RCM constraint. When this assistive robot is required to be backdriven by the surgeon, the relation between the interaction forces/moments and the motion with RCM constraint becomes challenging. This paper carefully formulates a hybrid position/force control scheme for this relationship when any readily available robot arm that is coupled with a force/torque sensor is used for an RCM task. The verification of the formulation is carried out on a readily available robot arm by implementing the additional constraints that are derived from a surgical robot application.Conference Object Velocity-Level Kinematics of a Continuously Variable Transmission System for Phri(Springer International Publishing AG, 2025) Dede, Mehmet İsmet Can; Dede, Mehmet Ismet Can; 01. Izmir Institute of Technology; 03.10. Department of Mechanical Engineering; 03. Faculty of EngineeringNew generation robots pave the way for physical human-robot interaction (pHRI) through improvements in control and design techniques. While the former is achieved with the help of a number of sensory information, variable stiffness actuators (VSA) are exploited for the design of these robots to achieve inherent compliance. Recently, continuously variable transmission-based VSA has been developed to be used for pHRI, specifically for haptics. The fundamental characteristic of this new CVT mechanism is that it regulates output position and torque independently via the sphere transmission element. In this study, velocity-level kinematics of this new CVT system is carried out to demonstrate its step-less speed variation feature. Moreover, simulations are conducted in ADAMS and Solidworks software packages at 8 transmission points selected unequally. Results show that the average value of overall ADAMS and Solidworks errors computed with respect to the computed velocity are reported as 1.09%, and 0.53%, respectively.Article Citation - WoS: 1Citation - Scopus: 1A New Safe Flexible Torsion Joint Design With Softening Stiffness Characteristics(Pergamon-elsevier Science Ltd, 2025) Dede, Mehmet İsmet Can; Görgülü, İbrahimcan; Kiper, Gökhan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyThis paper introduces a novel flexible joint design that enhances mechanical versatility. The design shows how to obtain bidirectional deflections from a unidirectional spring. It enables the parallel and serial connections of springs. It features multiple stiffness regions determined by applied load levels, eliminating the need for a clutch mechanism. Mechanical limits can be added to customize stiffness, offering more hardening or softening regions. The design also allows for connecting multiple flexible joint units in series. In a case study, the series flexible joint design is developed with two flexible joint units, providing a softening stiffness characteristic. The joint has rigid, stiff, and soft regions. When used as a series elastic actuator in a robot manipulator, the rigid region aims to conduct the tasks at low torque levels, i.e., trajectory tracking. The stiff region is preserved for collaborative tasks in human-robot interaction, while the soft region enhances the robot's safety in case of control failure or collision. Static and dynamic test results comply with the ideal model. This flexible joint design improves mechanical performance, safety, and adaptability.Article Citation - WoS: 1Citation - Scopus: 1Torque-Current Relationship of an Mr Brake for Its Open-Loop Control(Ieee-inst Electrical Electronics Engineers inc, 2024) Dede, Mehmet İsmet Can; Bozelli, Muhammed Rza; Dede, Mehmet Ismet Can; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyActive and semiactive actuators have been widely preferred for designing an actuation system for kinesthetic-type haptic devices. Among them, magnetorheological fluid-based brakes (MR brakes) offer potent properties, such as high torque/inertia ratio and less power consumption. However, one of the most critical issues to be resolved is their hysteresis behavior. Various methods for modeling the input/output relationship with hysteresis behavior exist. However, hysteresis compensation approaches, i.e., torque-current hysteresis model, are not widely studied for MR Brakes. Therefore, a hysteresis compensation model approach to account for the nonlinear behavior of MR Brake is proposed, and the model is experimentally validated in this article. The model consists of multiple splines and an algorithm that uses these splines in hysteresis compensation. Being relatively simple and easily implementable are the distinguished features of the presented model since an optimization method is not required. Furthermore, the performance of the proposed method is compared with two methods, torque-to-current mapping and inverse Prandtl-Ishlinskii method. The obtained experimental results are investigated with three performance metrics. Finally, the effect of the operational speed on the performance of the hysteresis compensation model is also discussed.Conference Object Citation - WoS: 1Citation - Scopus: 1Modeling a Magneto-Rheological Fluid-Based Brake Via a Neural Network Method(Springer international Publishing Ag, 2022) Kucukoglu, Sefa Furkan; Dede, Mehmet Ismet Can; Dede, Mehmet İsmet Can; Küçükoğlu, Sefa Furkan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyIdentifying the model of a magneto-rheological (MR) fluid-based brake is extremely important for designing and controlling a haptic device with hybrid actuation. Therefore, in this study, an Elman Recurrent Neural Network (ERNN) is designed to understand and model a characterization of an MR fluid-based rotational brake. Three important factors that affect the MR brake's performance are chosen as inputs: current, speed, and the first derivative of the input current. The proposed network is trained, and the performance of the network is tested with three different experimental scenarios. Then, the effect of these inputs on the system is investigated. According to the results, it can be said that the designed ERNN is a good candidate for modelling an MR brake.Conference Object Citation - WoS: 1Citation - Scopus: 2A New Correction Coefficient Formula for the Simplified Dynamic Model of a Surgical Robot(Springer international Publishing Ag, 2021) Ayit, Orhan; Dede, Mehmet Ismet Can; Dede, Mehmet İsmet Can; Ayit, Orhan; 03.10. Department of Mechanical Engineering; 03. Faculty of Engineering; 01. Izmir Institute of TechnologyExecution of model-based control algorithms such as computed torque technique requires the knowledge of the dynamic model of the robotic system. In our work, the active part of the surgical robot, NeuRoboScope, has a parallel kinematics architecture and the dynamic model is relatively complicated to run in a microprocessor with limited computing capabilities. For this reason, we formulated a simplified dynamic model to run in the selected microprocessor. In this work, a new formula for calculating the correction coefficients is described to minimize the errors in the whole orientation range of the robot's base platform. This new formula is examined in terms of execution time and the result is reported in this paper.