PHYSICAL IMPLEMENTATION AND NUMERICAL VERIFICATION OF MACRO SCALE PROTOTYPE OF A BIO-INSPIRED MEDICAL MICRO ROBOT SWIMMING IN CYLINDRICAL CHANNELS
Ahmet Fatih Tabak
Mechatronics, Ph.D. Dissertation, 2012
Assoc. Prof. Serhat Yeşilyurt (Thesis supervisor), Asst. Prof. Ahmet Onat, Assoc. Prof. Ayhan Bozkurt, Assoc. Prof. Osman Uğur Sezerman, Prof. Dr. Hasan Güneş
Date &Time: August 7th, 2012 – 14:00
Place: FENS G029
Modeling and control of swimming untethered micro robots are important for future therapeutic medical applications. Bio-inspired propulsion methods emerge as realistic substitutes for hydrodynamic thrust generation in micro realm. Accurate modeling, power supply, and propulsion-means directly affect the mobility and maneuverability of swimming micro robots with helical or planar wave propagation.
Flow field around a bio-inspired micro swimmer comprised of a spherical body and a rotating helical tail is investigated with time-dependent three-dimensional computational fluid dynamics (CFD) model. Analytical hydrodynamic studies on the bodies of well known geometries submerged in viscous flows reported in literature do not address the effect of hydrodynamic interactions between the body and the tail of the robot in unbounded viscous fluids. Hydrodynamic interactions are explained qualitatively and quantitatively with the help of CFD-model.
A cm-scale powered bio-inspired swimmer robot with helical tails is manufactured including a payload and a replaceable rigid helical tail. The payload includes on-board power supply and remote-control circuitry. A number of helical tails with parameterized wave geometry are used. Swimmer performed in cylindrical channels of different diameters while fully submerged in an oil-bath of high viscosity.
A real-time six degrees-of-freedom hydrodynamic model is developed and implemented to predict the rigid-body motion of the swimming robots with helical and traveling-plane-wave tails. Results of hydrodynamic models with alternative resistance coefficients are compared against CFD-simulations and in-channel swimming experiments with different tails. Validated hydrodynamic model is further employed to investigate efficient geometric designs with different wave propagation methods within a predefined design space.