Person: BEBEK, Özkan
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Özkan
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BEBEK
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ArticlePublication Metadata only Heart motion prediction based on adaptive estimation algorithms for robotic assisted beating heart surgery(IEEE, 2013) Tuna, E. E.; Franke, T. J.; Bebek, Özkan; Shiose, A.; Fukamachi, K.; Çavuşoğlu, M. C.; Mechanical Engineering; BEBEK, ÖzkanRobotic-assisted beating heart surgery aims to allow surgeons to operate on a beating heart without stabilizers as if the heart is stationary. The robot actively cancels heart motion by closely following a point of interest (POI) on the heart surface - a process called active relative motion canceling. Due to the high bandwidth of the POI motion, it is necessary to supply the controller with an estimate of the immediate future of the POI motion over a prediction horizon in order to achieve sufficient tracking accuracy. In this paper, two least-squares-based prediction algorithms, using an adaptive filter to generate future position estimates, are implemented and studied. The first method assumes a linear system relation between the consecutive samples in the prediction horizon. On the contrary, the second method performs this parametrization independently for each point over the whole the horizon. The effects of predictor parameters and variations in heart rate on tracking performance are studied with constant and varying heart rate data. The predictors are evaluated using a three-degree-of-freedom (DOF) test bed and prerecorded in vivo motion data. Then, the one-step prediction and tracking performances of the presented approaches are compared with an extended Kalman filter predictor. Finally, the essential features of the proposed prediction algorithms are summarized.Conference ObjectPublication Metadata only Improving the safety of medical robotic systems(IEEE, 2018-10-09) Dibekçi, Ayşan; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Dibekçi, AyşanThe significance of the robots in the medical field have been increasing rapidly. Humans and robots working together increases the strengths and decreases the limitations of surgical operations. Human life makes safety the most important problem for medical robots, for which there are no universal standards. This paper presents detailed design methods for increasing medical robots' safety by considering issues of sterilization, robot's size, operating room placement of the robot, the robot mechanics, selection of the electromechanical components, drive mechanism, stiffness, sensor redundancy, software application, and hazard identification and analysis. The proposed safety design concepts were put into practice on a surgical robot prototype and the outcomes are discussed.Conference ObjectPublication Metadata only Reducing charging costs for electric vehicles with bi-directional charging(IEEE, 2023) Zincircioğlu, Emircan; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Zincircioğlu, EmircanElectric vehicles (EVs) have gained popularity as eco-friendly and energy-efficient modes of transportation. How-ever, the high cost of charging infrastructure remains a significant barrier to the widespread adoption of EVs. Bidirectional charging (BDC) is a promising solution that allows EVs to charge from the grid and supply excess power back to the grid. In this paper, we present a simulation-based study of BDC using MATLAB/Simulink and Simscape to explore the potential of BDC to reduce charging costs. We modeled an EV charging station equipped with BDC capabilities and evaluated the cost savings achieved through BDC under two different scenarios. Our findings suggest that BDC has the potential to reduce charging costs significantly, making EVs more economically viable.ArticlePublication Metadata only Personal inertial navigation system assisted by mems ground reaction sensor array and interface ASIC for GPS-denied environment(IEEE, 2018-11) Guo, Q.; Deng, W. H.; Bebek, Özkan; Cavusoglu, M. C.; Mastrangelo, C. H.; Young, D. J.; Mechanical Engineering; BEBEK, ÖzkanA personal inertial navigation system (PINS) assisted by a microelectromechanical systems (MEMS)-based 13 × 26 ground reaction sensor array (GRSA) and a low-power interface application-specified integrated circuit (ASIC) has been designed and demonstrated for GPS-denied environment. The GRSA operating in a contact mode achieves a sensitivity of approximately 3.7 fF/kPa at each sensor node. An electronic interface system, consisting of a capacitance-to-voltage (C/V) converter followed by a correlated double sampling stage, is designed to convert the GRSA capacitance change to an analog output voltage. The analog output voltage is then digitized by a 12-bit cyclic analog-to-digital converter (ADC). Switch capacitance compensation technique is employed to ensure the ADC performance. The ASIC is fabricated in 0.35-μm CMOS process and dissipates a power of 3 mW. The prototype system incorporates a GRSA, an ASIC, and a commercial nine degreeof-freedom (DOF) inertial measurement unit (IMU) in the heel region of a boot. The GRSA can determine an accurate foot-onground timing based on the pressure profiles detected during walking, thus enabling an accurate position calculation and a precise zero velocity update. Furthermore, a system calibration procedure measures the IMU inherent directional drift and scaling factor errors, and compensates them for the navigation data to achieve a superior performance. The prototype system demonstrates a position accuracy of approximately 5.5 m over a navigation distance of 3100 m. The prototype system also achieves a consistent performance over different field tests with various distances and random paths. System characterization results further indicate a tradeoff between sensor array size and system resolution for a given navigation performance requirement, thus providing a design guideline for future system optimization.Conference ObjectPublication Metadata only A personal navigation system using mems-based high-density ground reaction sensor array and inertial measurement unit(IEEE, 2015) Guo, Q.; Bebek, Özkan; Çavuşoğlu, M. C.; Mastrangelo, C. H.; Young, D. J.; Mechanical Engineering; BEBEK, ÖzkanThis paper describes a prototype personal navigation system developed for position tracking under GPS denied environments by employing a commercial inertial measurement unit (IMU) and a MEMS-based ground reaction sensor array (GRSA). The GRSA is used to provide zero-velocity updating for the IMU. A Kalman filter further estimates the IMU output bias during the zero-velocity period, which is then removed from the IMU's subsequent output signals to improve the navigation accuracy. Seven 10-minute square-loop walking tests were performed to achieve an in-plane navigation accuracy ranging from 0.4 meter to 3.4 meter with a vertical position accuracy of approximately 1 meter. A further improved performance over an extended navigation time is expected through enhancing the GRSA sensitivity.Conference ObjectPublication Metadata only Topology optimization-based design and development of a compact actuator with a high torque-to-weight ratio for quadrupeds(IEEE, 2022) Akın, Barış; Özçınar, Erim Can; Balcı, Barış; Emre, Sinan; Şendur, Polat; Bebek, Özkan; Ünal, Ramazan; Uğurlu, Regaip Barkan; Mechanical Engineering; ŞENDUR, Polat; BEBEK, Özkan; ÜNAL, Ramazan; UĞURLU, Regaip BarkanThis paper presents the design, development, and testing procedures for a compact actuator with a high torque-to-weight ratio, generally aimed to actuate legged robots, e.g., quadrupeds. The main goal of designing the actuator was to keep its total weight minimum while ensuring a high torque output. Therefore, the following design steps were implemented: i) the actuator was designed in accordance with the torque output requirement and the stress distribution that was mapped on actuator frames, ii) topology optimization was conducted on the initial design and it is modified in accordance with optimization results, and iii) the optima actuator design was built and tested on in a realistic scenario in which it powered an actual quadruped robot for validation. As the result, the proposed actuators could track the desired walking trajectory with a relatively low error. In conclusion, continuous torque output of 48 Nm was obtained via a lightweight (1.6-1.7 kg) actuator design.Conference ObjectPublication Open Access Discussing modernizing engineering education through the Erasmus + Project Titled "Open Educational Resources on Enabling Technologies in Wearable and Collaborative Robotics (WeCoRD)(Ege University) Kılıç-Bebek, Ebru; Nizamis, K.; Karapars, Gülhis Zeynep; Gökkurt, Muharrem Ali; Ünal, Ramazan; Bebek, Özkan; Vlutters, M.; Vander Poorten, E.; Borghesan, G.; Decré, W.; Aertbelien, E.; Borisova, O.; Borisov, I.; Kolyubin, S.; Kodal, M. I.; Uğurlu, Regaip Barkan; Industrial Design; Sectoral Education and Professional Development; Mechanical Engineering; BEBEK, Ebru Kılıç; KARAPARS, Gülhis Zeynep; GÖKKURT, Muharrem Ali; ÜNAL, Ramazan; BEBEK, Özkan; UĞURLU, Regaip BarkanThe Erasmus + project titled “Open Educational Resources on Enabling Technologies in Wearable and Collaborative Robotics (WeCoRD)", can serve as a model to establish strategic international and multidisciplinary partnerships to modernize engineering education. WeCoRD project is a collaboration among internationally renowned institutions from Turkey, Belgium, Russia, and the Netherlands to create an innovative course on wearable and collaborative robotics with Open Educational Resources (OERs) and an online Virtual Lab aimed at accessibility across Europe. This collaboration involves many fields from engineering, health, and design disciplines as well as an industry partner from the automotive manufacturing sector. The main objectives of the project are to: (1) prepare a graduate-level course in wearable and collaborative robotics, (2) enhance EU higher education capacity in the field with clear use-case scenarios from the industry and medical applications, (3) provide open-source materials including a virtual lab, and (4) fill the skill gap between the industry and the academia while also aiming a continued professional development. With these goals which aim to modernize engineering education and make it more relevant to the industry, the WeCoRD project brings both multidisciplinary and interdisciplinary aspects of robotics education to a new level. Each intellectual output (IO) of the project is allocated to a project partner based on their expertise. The course module design and development is planned as follows: The IO1 (the first course module) on “Components for wearable and collaborative robots” is led by Ozyegin University, Turkey; the IO2 (the second course module) on “Modeling, design and control or wearable and collaborative robots as systems” is led by ITMO, Russia; the IO3 (the third course module) on “Human-robot interaction for wearable and collaborative robots” is led by KU Leuven, Belgium; the IO4 (the fourth course module) on “Medical applications” is led by U.Twente; the IO5 (integration of the first three course modules into one course) on the graduate-level course to be integrated into graduate degree programs and to be adopted for continued professional development (CPD) training programs, as well as the translation of the course materials into Turkish is led by KU Leuven, Belgium; the IO6 on the “Virtual Lab” is led by ITMO, Russia; and finally IO7 on the “Video Collection” is led by Ozyegin University, Turkey. FORD-Otosan, which is one of the industry partners from Turkey will host students, provide site visits and offer workshops. Each project partner and their contributions will be addressing the fundamental need for modernizing engineering education through students’ active participation and boosting students’ skill development. In addition to multidisciplinary and interdisciplinary exposure, students will get a chance to work with industry partners and learn through authentic problem solving and relevant feedback. Providing a deeper and more effective learning experience will be among the core design principles of the course modules, labs, videos, and industry collaborations.ArticlePublication Open Access Mars gezgini prototipi Merih-2(Gazi Üniversitesi, 2018-12) Balcı, Barış; Yıldırım, Mehmet Can; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Balcı, Barış; Yıldırım, Mehmet CanMerih-2, Özyeğin Üniversitesi Rover Takımı tarafından University Rover Challenge 2016 ve European Rover Challenge 2016’ya katılmak ve Mars koşullarında görev yapmak için tasarlanan gezgindir. Sürüş için Merih-2’nin 6 adet özel tasarım tekeri bulunmaktadır. Yüksek çekiş için bütün tekerler elektrik motorlarıyla tahrik edilmiştir. Gezginin ilerlerken yön değiştirmesi, ön ve arka tekerlerin beraber yönlerinin değiştirilmesiyle mümkün kılınmıştır. Tekerlerden en az dördünün yere basmasını sağlayan bir Külbütör-Boji mekanizması ve bu mekanizmanın dengeleyicisi bir diferansiyel bulunmaktadır. Merih-2 ayrıca, çevredeki objelerin manipülasyonu için 4 serbestlik dereceli bir robot kola sahiptir. Bu robotik kola çok fonksiyonlu bir tutucu takılmış ve tornavida alma, şalterleri açma ve kapama gibi astronotlara yardım görevlerini yapması planlanmıştır. Bu makalede; Merih-2’nin tasarım ayrıntıları, üretilen prototipten elde edilen kazanımlar ve gezginin operasyon ve yaşanan olumsuzlukları ortadan kaldırabilecek öneriler anlatılmaktadır.ArticlePublication Open Access Towards active tracking of beating heart motion in the presence of arrhythmia for robotic assisted beating heart surgery(Plos, 2014-07-21) Tuna, E. E.; Karimov, J. H.; Liu, T.; Bebek, Özkan; Fukamachi, K.; Çavuşoğlu, M. C.; Mechanical Engineering; BEBEK, ÖzkanIn robotic assisted beating heart surgery, the control architecture for heart motion tracking has stringent requirements in terms of bandwidth of the motion that needs to be tracked. In order to achieve sufficient tracking accuracy, feed-forward control algorithms, which rely on estimations of upcoming heart motion, have been proposed in the literature. However, performance of these feed-forward motion control algorithms under heart rhythm variations is an important concern. In their past work, the authors have demonstrated the effectiveness of a receding horizon model predictive control-based algorithm, which used generalized adaptive predictors, under constant and slowly varying heart rate conditions. This paper extends these studies to the case when the heart motion statistics change abruptly and significantly, such as during arrhythmias. A feasibility study is carried out to assess the motion tracking capabilities of the adaptive algorithms in the occurrence of arrhythmia during beating heart surgery. Specifically, the tracking performance of the algorithms is evaluated on prerecorded motion data, which is collected in vivo and includes heart rhythm irregularities. The algorithms are tested using both simulations and bench experiments on a three degree-of-freedom robotic test bed. They are also compared with a position-plus-derivative controller as well as a receding horizon model predictive controller that employs an extended Kalman filter algorithm for predicting future heart motion.ArticlePublication Metadata only Design of a parallel robot for needle-based interventions on small animals(IEEE, 2013-02) Bebek, Özkan; Hwang, M. J.; Çavuşoğlu, M. C.; Mechanical Engineering; BEBEK, ÖzkanIn this paper, a novel 5-degrees-of-freedom robot for performing needle-based interventions on small animal subjects is presented. The robot can realize dexterous alignment of the needle using two parallel mechanisms, and has a syringe mechanism to insert needles to subjects. Operations on small animals require high accuracy positioning during needle insertion. The kinematic calibration procedure of the robot using an optical tracker as an external sensor is presented to enhance accuracy of the system. After the kinematic calibration, the positioning accuracy of the needle tip is measured as 0.4 mm RMS. The robot design is light weight, and has a motion bandwidth of 4 Hz. The robot can track reference trajectories with a closed-loop controller.