Nonlinear Modeling Application to Micro-/Nanorobotics

Abstract

Micro-/nanorobots have the potential to revolutionize medicine by specific applications, such as targeted drug delivery, biopsy, hyperthermia, brachytherapy, scaffolding, in vivo ablation, sensing, marking, and stem cell therapy. Application of microrobots can move us to the stage that monitoring diseases, precise localized drug delivery, minimally invasive surgery, and novel therapies such as stem cell therapy are done using the tools inside the human body. Since size is small and velocity is low, microrobots have a very low Reynolds (Re) number. A low Re number indicates the dominance of viscous forces and hence, swimming methodologies at microscale are different from those at the macroscale. Although motion of these microrobots is linear at Stokes flow, hydrodynamics of flagella and cilia involve nonlinear models that should be addressed for precise actuation and control of micro-/nanorobots. Nonlinear modeling is of great significance especially when the artificial filaments are fabricated from soft materials to mimic natural flagella and cilia and provide enhanced propulsion. A great challenge in developing an autonomous microrobotic system is to provide power and control for the microrobot. Since untethered microrobots can be used as implants and have a higher maneuverability, the control system should benefit from a wireless actuation mechanism. Magnetic actuation can transfer a reasonable amount of power wirelessly. There are different systems for generating magnetic field and gradients: Permanent magnets Helmholtz coils, Maxwell coils, or a combination thereof Magnetic resonance imaging (MRI) systems Customized sets of electromagnetic coils.