Person: BEBEK, Özkan
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Özkan
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BEBEK
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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.ArticlePublication Metadata only A novel driving pattern to actualize haptic effects in mobile devices(IEEE, 2021-05) Kirişken, Barbaros; Mansouri, Deniz; Şendur, Polat; Özkan, Bebek; Mechanical Engineering; ŞENDUR, Polat; BEBEK, Özkan; Kirişken, Barbaros; Mansouri, DenizHaptic interactions in consumer devices have become more critical with immersive streaming content by including high-resolution video and sound as well as tactile information. Mobile devices such as tablets and smartphones are significantly limited for creating effective haptic illusions as they are too small in size to accommodate complex actuators and are without mechanical support. Recent studies and commercial products show that the use of larger and complex multi-coil linear resonant actuators (LRAs) can significantly improve tactile perception quality at the expense of significant design constraints such as size and cost. In this study, a novel driving pattern and complete system design are presented that enables similar quality haptic effects using a simple LRA system. The proposed driving pattern consists of segmented signals with different frequencies and duty cycles determined from finite element-based modal analysis, and it was used to simulate the two most common touch controls, the button and slider, on a mobile device. Numerical and experimental results showed that the system can achieve a 3x reduction in cost, a 9 x reduction in weight, and a 6 x reduction in volume. User tests comparing smartphones with the novel LRA driving pattern and the benchmark devices demonstrated the feasibility of a low-cost solution to improve haptic effects and illusions.ArticlePublication Metadata only Transdisciplinarity as a learning challenge: Student experiences and outcomes in an innovative course on wearable and collaborative robotics(IEEE, 2023-06) Kılıç-Bebek, Ebru; Nizamis, K.; Vlutters, M.; Bebek, Özkan; Karapars, Gülhis Zeynep; Ünal, Ramazan; Yılmaz, Deniz; Uğurlu, Regaip Barkan; Industrial Design; Sectoral Education and Professional Development; Mechanical Engineering; Mitchell, J.; BEBEK, Ebru Kılıç; KARAPARS, Gülhis Zeynep; BEBEK, Özkan; ÜNAL, Ramazan; UĞURLU, Regaip Barkan; Yılmaz, DenizContribution: This study provides evidence for the benefit of short online courses for transdisciplinary competence development of graduate students. It shows the significant challenges students face while learning, and provides instructional recommendations to improve students’ learning quality and professionalism. Background: Developing wearable and collaborative robots requires industry collaboration and transdisciplinary competence. Industry’s involvement in long-term programs is becoming infeasible, and the nature of transdisciplinary learning has not been explored to inform instructional practices. Intended Outcomes: This study aimed to provide instructional recommendations based on an in-depth examination of a diverse group of graduate students’ learning and teamwork experiences as well as outcomes in a 5-day online transdisciplinary course. Application Design: 31 graduate students of engineering, industrial design, and health fields from 4 countries participated in online mixed-discipline instructional sessions and teams to address a real industry challenge. A mixed-methods approach was used to examine students’ experiences and learning outcomes based on a competence measure, session participation data, student journal entries, team progress reports, team elaboration visuals, and final team presentations. Findings: Students’ knowledge of industrial design, medical considerations, ethics and standards, effective teamwork, and self-regulated learning were increased. Students’ high motivation helped them deal with the challenges involved. Daily student journals, team reports, and visual elaboration tools were found to be beneficial for determining the challenges and learning quality. The observed student progress within 5 days is promising, making it worthwhile to further explore the benefits of short online courses for increasing graduates’ readiness and establishing university-industry collaborations in education.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.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.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 Metadata only Development of an antagonistically actuated smart joint(Trans Tech Publications, 2017) Vahidyeganeh, Ali; Şimsek, Görkem Muttalip; Jabeen, Saher; Bebek, Özkan; Yapıcı, Güney Güven; Mechanical Engineering; BEBEK, Özkan; YAPICI, Güney Güven; Vahidyeganeh, Ali; Şimsek, Görkem Muttalip; Jabeen, SaherShape memory alloys with their phase transformation properties; have been broadly implemented in smart structures. In this study, a functional design is presented where two wires actuate antagonistically to achieve motion in bending. Effect of heat treatment parameters on the actuator materials is investigated. For this purpose, a novel experimental test bench appropriate for characterizing a smart joint is presented, and joint performance including actuation force and cyclic behavior are demonstrated. Accordingly, a smart joint configuration capable of 60 degrees bending with a repeatability of 50 cycles is developed.ArticlePublication Metadata only Development and 3D spatial calibration of a parallel robot for percutaneous needle procedures with 2D ultrasound guidance(World Scientific, 2017-12-01) Ahmad, Mirza Awais; Orhan, Sabri Orçun; Yıldırım, Mehmet Can; Bebek, Özkan; Mechanical Engineering; BEBEK, Özkan; Ahmad, Mirza Awais; Orhan, Sabri Orçun; Yıldırım, Mehmet CanRobotic systems are being applied to medical interventions as they increase the operational accuracy. The proposed autonomous and ultrasound guided 5-DOF parallel robot can achieve such accuracy for needle biopsies, which particularly demand precise needle positioning and insertion. In this paper, the robot's mechanical design, system identifications, and the design of its controller are explained. A torque computed controller with gravity compensation and friction models, yielding a 0.678mm RMS position error for the needle tip, was used. A novel method was used for 3D space calibration of the images for detecting the volume of interest in the biopsy procedure by a multipoint crosswire phantom with parallel threads. The calibration technique had a validation RMS error of 0.03mm.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.Conference ObjectPublication Metadata only Contact force distribution using centroidal momentum feedback for quadruped locomotion(IEEE, 2023) Özçınar, Erim Can; Bebek, Özkan; Uğurlu, Regaip Barkan; Mechanical Engineering; BEBEK, Özkan; UĞURLU, Regaip Barkan; Özçınar, Erim CanThis paper proposes a method to distribute contact forces to eliminate undesired torso orientation fluctuations and regulate heading during dynamic quadruped trot-walking motion. The proposed method makes use of centroidal momentum, an essential physical quantity in characterizing the whole-body behavior and overall balance of the robot. The contact forces are computed using centroidal momentum feedback and injected into the locomotion controller via virtual model control, which can render virtual forces to regulate robot-environment interaction. In combining the virtual model control and centroidal momentum feedback, one can attain dynamically feasible contact force distribution, a key objective in controlling dynamic quadruped locomotion. In order to validate the proposed method, a series of simulation experiments were conducted using a realistic model of our quadruped robot Kara. As a result, we obtained dynamically consistent trot-walking behavior in which torso orientation and heading were well regulated.