Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Institution Author: search.filters.institutionAuthor.Ayit, Orhan

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  • Article
    Citation - WoS: 7
    Citation - Scopus: 7
    Gravity Compensation of a 2r1t Mechanism With Remote Center of Motion for Minimally Invasive Transnasal Surgery Applications [article]
    (Cambridge University Press, 2023) Aldanmaz, Ataol Behram; Ayit, Orhan; Kiper, Gökhan; Dede, Mehmet İsmet Can
    This work addresses the gravity balancing of a 2R1T (2 rotations – 1 translation) mechanism with remote center of motion. A previously developed balancing solution is modified and applied to a prototype and test results are presented. The mechanism is an endoscope holder for minimally invasive transnasal pituitary gland surgery. In this surgery, the endoscope is inserted through a nostril of the patient through a natural path to the pituitary gland. During the surgery, it is vital for the manipulator to be statically balanced so that in case of a motor failure, the patient is protected against any harmful motion of the endoscope. Additionally, static balancing takes the gravitational load from the actuators and hence facilitates the control of the mechanism. The mechanism is a 2URRR-URR type parallel manipulator with three legs. The payload mass is distributed to the legs on the sides. By using counter-masses for two links of each leg, the center of mass of each leg is lumped on the proximal link which simplifies the problem to balancing of a two degree-of-freedom inverted pendulum. The two proximal links with the lumped mass are statically balanced via springs. Dynamic simulations indicate that when the mechanism is statically balanced, generated actuator torques are reduced by 93.5%. Finally, the balancing solution is implemented on the prototype of the manipulator. The tests indicate that the manipulator is statically balanced within its task space when the actuators are disconnected. When the actuators are connected, the torque requirements decrease by about 37.8% with balancing.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 5
    Toward Safe and High-Performance Human-Robot Collaboration Via Implementation of Redundancy and Understanding the Effects of Admittance Term Parameters
    (Cambridge University Press, 2022) Kanık, Mert; Ayit, Orhan; Dede, Mehmet İsmet Can; Tatlıcıoğlu, Enver
    Summary Today, demandsin industrial manufacturing mandate humans to work with large-scale industrial robots, and this collaboration may result in dangerous conditions for humans. To deal with this situation, this work proposes a novel approach for redundant large-scale industrial robots. In the proposed approach, an admittance controller is designed to regulate the interaction between the end effector of the robot and the human. Additionally, an obstacle avoidance algorithm is implemented in the null space of the robot to prevent any possible unexpected collision between the human and the links of the robot. After safety performance of this approach is verified via simulations and experimental studies, the effect of the parameters of the admittance controller on the performance of collaboration in terms of both accuracy and total human effort is investigated. This investigation is carried out via 8 experiments by the participation of 10 test subjects in which the effect of different admittance controller parameters such as mass and damper are compared. As a result of this investigation, tuning insights for such parameters are revealed.
  • Conference Object
    Citation - WoS: 1
    Citation - Scopus: 2
    A New Correction Coefficient Formula for the Simplified Dynamic Model of a Surgical Robot
    (Springer international Publishing Ag, 2021) Ayit, Orhan; Dede, Mehmet Ismet Can
    Execution 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.
  • Book Part
    Citation - WoS: 1
    Citation - Scopus: 2
    Viscoelastic Modeling of Human Nasal Tissues With a Mobile Measurement Device
    (Springer, 2019) Işıtman, Oğulcan; Ayit, Orhan; Vardarlı, Eren; Hanalioğlu, Şahin; Işıkay, İlkay; Berker, Mustafa; Dede, Mehmet İsmet Can
    Modeling the dynamic of tool-tissue interaction for the robotic minimally invasive surgeries is one of the main issues for designing appropriate robot controllers. A mobile measurement device is produced in order to model some nasal tissues of a human. This mobile device is a hand-held one which measures the applied moments and relative angular displacements about a fixed pivot point. The ex-vivo measurements are realized by surgeons on a relatively fresh human cadaver head. The tip of the nose and the nasal concha are the two tissues that are investigated. In this study, five different viscoelastic models are considered; Elastic, Kelvin- Voight, Kelvin-Boltzmann, Maxwell and Hunt-Crossley. The results are evaluated and cross-validated on each data set. Hunt-Crossley and Kelvin-Boltzmann models provided the minimum root-mean-square (RMS) error among the other models.
  • Conference Object
    The Effects of Admittance Term on Back-Drivability
    (Springer, 2018) Işıtman, Oğulcan; Ayit, Orhan; Dede, Mehmet İsmet Can
    In the design of kinesthetic haptic devices, there are mainly impedance type and admittance type device. In a customary scenario, the human operator back-drives the haptic device by holding and providing motion to the handle of the haptic device. If the type of transmission system does not allow passive back-drivability, then the back-drivability is satisfied by the use of an admittance controller. This type of a haptic device is said to have admittance structure. The selection of the admittance term in this controller plays a critical part in the task execution performance. Determination of this term is not trivial and the optimal parameters depend on not only the key performance criteria but also on the human operator. An experimental study is carried out in this work to determine the effect of the admittance term parameters on the performance of human operators in terms of the energy efficiency and the best accuracy. In this paper, the experimental set-up and the results of the experiments are presented and discussed.