Modeling and Control of Untethered Biomicrorobots in a Fluidic Environment Using Electromagnetic Fields

This paper investigates fundamental design, modeling, and control issues related to untethered biomedical microrobots guided inside the human body through external magnetic fields. Proposed areas of application for these microrobots include sensing, diagnosis, and surgical procedures in intraocular, cardiovascular, and inner-ear environments. A prototype microrobot and steering system are introduced. Fluid drag experiments performed on the prototype robot show that the 950 × 400 μm elliptical shape has a spherical equivalent diameter of 477 μm. Drag forces combined with saturation magnetization (5 × 105 A/m) of the prototype indicate that the required magnetic field gradients for application inside the vitreous humor and blood vessels are on the order of 0.7 T/m. KEY WORDS—biomedical, microrobotics, wireless microrobot, magnetic microrobot, MEMS, microassembly