Sharif Digital Repository

In the recent decade, researchers in the field of minimally invasive medicine have come up to the idea of utilizing micro organisms as smart micro robots. The advantage with this idea is the fact that problems such as energy supply and maneuvering are resolved for these sorts of micro swimmers. In this current work, a new numerical method for investigation of micro swimming is developed which is computationally efficient in characterizing locomotion of micro swimmers and using a finite element method software, locomotion of Paramecium has been investigated inside and outside a capillary tube. According to simulation results, it is possible to design a controlling system which is capable of... 

In this study, two micro swimmers have been modeled using computational fluid dynamics and the motion specifications have been presented. The mechanisms can be used for different applications like drug delivery, monitoring, doing tasks in dangerous environments like robots and etc… . These moving mechanisms are inspired from a type of plankton named “cladoceran Podon Intermedius”, accordingly we have compared our results with data obtained by particle image velocimetry. For CFD simulation, an unstructured 2-dimensional mesh has been generated. Dynamic meshing has also been utilized in a meshing zone around the moving parts. Unsteady simulations were run for axisymmetric and plane symmetry... 

Micro-Robotics is implemented by researchers inclusively in last decades in different fields such as, biolotechnology, space, army and medical engineering. However, micropositioning is the main challenge in such projects, since determination and control of micro-robot’s position for drug delivery, artificial insemination and other medical applications are too significant. In this thesis, a method for controlling a microswimmer’s position in two dimention by an external magnetic field has been proposed. Modelling of magnetic field and magnetic gradient are some important challenges due to the fact that in control loop, a fast and optimal model for estimation of magnetic filed and gradient is... 

In this study, at first modeling of a self-propelled microrobot and its hydrodynamic effects on flow field are investigated. Then, a cascade controller has been designed for the fully actuated microrobot in order to track the desired time trajectories. Next, in order to design an optimal controller to decrease energy consumption, regardless of tracking the desired orientation trajectory compared to the desired position trajectory, the fully actuated microrobot would change to over actuated microrobot. Thus, it would be able to orient freely itself according to the flow field so that reduce the energy consumption. By applying the optimal controller on the over actuated microrobot, it was... 

Nowadays, regarding the wide achievements in micro scale technology, it is possible to manufacture a micro robot. Micro swimmer have extensive applications in different fields especially in medical sciences. One of the most important problems of the micro robot is their propulsion system. The locomotion of microorganisms in fluids is ubiquitous and plays an important role in numerous biological processes. The physics of swimming governing life under the microscope is very different from the one we experience in the macroscopic world. This project is aimed at designing a propulsion system for a micro swimmer based on the swimming mechanism of the eukaryotic Spermatozoa. Simplicity to build is...