Tabak, Ahmet Fatih

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Tabak, Ahmet Fatih
A.,Tabak
A. F. Tabak
Ahmet Fatih, Tabak
Tabak, Ahmet Fatih
A.,Tabak
A. F. Tabak
Ahmet Fatih, Tabak
Tabak, A.F.
Job Title
Dr. Öğr. Üyesi
Email Address
Ahmetfatıh.tabak@khas.edu.tr
Main Affiliation
Mechatronics Engineering
Status
Former Staff
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Scholarly Output

11

Articles

3

Citation Count

0

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0

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2020 - 20213
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Now showing 1 - 3 of 3
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    Article
    Simulation Studies for Motion Control of Multiple Biohybrid Microrobots in Human Synovial Fluid With Discontinuous Reference Signals
    (2021) Tabak, Ahmet Fatih; Tabak, Ahmet Fatih
    It is envisioned that biomedical swarms are going to be used for therapeutic operations in the future. The utilization of a single robot in live tissue is not practical because of the limited volume. In contrast, a large group of microrobots can deliver a useful amount of potent chemicals to the targeted tissue. In this simulation study, a trio of magnetotactic bacteria as a task-force, Magnetospirillum Gryphiswaldense MSR-1, is maneuvered via adaptive micro-motion control through an external magnetic field. The magnetic field is induced by a single permanent magnet positioned by an open kinematic chain. The coupled dynamics of this small group in the human synovial tissue is simulated with actual magnetic and fluidic properties of the synovial liquid. The common center of mass is tracked by the equation of motion. The overall hydrodynamic interaction amongst all three bacteria is modeled within a synovial medium confined with flat surfaces. A bilateral control scheme is implemented on top of this coupled model.The position of the common center of mass is used as the reference point to the end-effector of the robotic arm. The orientation of the magnetic field is rotated to change the heading of the bacterial-group in an addressable manner. It has been numerically observed that controlling the common swimming direction of multiple bacteria is fairly possible. Results are presented via the rigid-body motion of the robotic task-force as well as the fluidic and magnetic force-components acting on the bacteria along with the bilateral control effort in all axes.
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    Article
    Independent Joint Control Simulations on Adaptive Maneuvering of a Magnetotactic Bacterium via a Single Permanent Magnet
    (2020) Tabak, Ahmet Fatih
    The use of micro-robotic systems in non-invasive medicine has been heavily promoted in the literature for the last decade. The studies usually focus on artificial or biohybrid microswimmers of various origins subject to the effect of an external electromagnetic field controlled by a computer. Although there exist several motion control studies shared to date, control of a bio-hybrid microswimmer has rarely been demonstrated employing an open kinematic chain, in detail. In this work, motion control of an isolated magnetotactic bacterium cell (Magnetospirillum Gryphiswaldens) is presented via a magnetic field actively positioned by an open kinematic chain. The cell is modeled with its complete environment to make it as realistic as possible along with the magnetic torque, which is induced by a single magnet attached at the end effector of a robotic arm, exerted on it for maneuvering control. The control is based on a proportional – integral – derivative (PID) gain scheme with adaptive integral gain to focus on a particular steady-state error with discontinuous reference signals. The control signal is transformed into pulse width modulation (PWM) signals to drive the motors articulating the joints of the open kinematic chain, the inverse kinematics of which is designed to be simple enough to achieve independent joint control. A numerical analysis of the coupled system is carried out in the time domain. The performance of the said motion control approach is investigated for each degree of freedom for the planar motion of the microswimmer. Simulations demonstrate a planar open kinematic chain is capable of control the gait of the microswimmer while following its trajectory near a planar boundary via independent joint control. Furthermore, simulations demonstrate that the effective magnetic inertia and the shear stress results in a small but certain lag in the motion control performance of the overall system.
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    Article
    Non-Contact Micromanipulation Of A Single E. Coli Minicell
    (2021) Tabak, Ahmet Fatih; Tabak, Ahmet Fatih; Sürer, Jiyan
    Today, a variety of methods are available for micro-scale transportation without inflicting damage on biological samples. There are several numerical and experimental studies in the literature that make use of microrobots to manipulate particles in non-contact performances. One of the applications used to mitigate the aforementioned risk is non-contact micro manipulation by hydrodynamic effects, and with the micro-objects floating around the core of a free vortex this method can be implemented effectively. However, a robotic model predicting the dynamics of such microsystems is rare in the literature and yet to be applied for manipulation of a bacterium. In this paper, a single magnetic particle that is assumed to be held in a fixed place while rotated by an external magnetic field, and an E. Coli minicell swimming in the free vortex induced by the described rotation. The mathematical model and the numerical simulations presented here via linear set of equations for rigid body-motion under the magnetic and hydrodynamic forces are built in cylindrical coordinates. Results demonstrate the numerical stability of the robotic model along with predicted-motion pointing to a steady periodic orbit around the vortex center for a total of 600 periods of simulated magnetic field rotation. Results to the numerical experiments are focused on the rigid-body rotation of E. Coli minicell, the propulsive force of the rotating helical tail of the bacterium, and acceleration, speed, and displacement of the bacterium with respect to the center of the vortex.