Millirobot magnetic manipulation for ocular drug delivery with sub millimeter precision

Significant progress has been made in the development of magnetic micromanipulation for minimally invasive surgery. The development of systems to localize millimetric size robots during magnetic navigation and without line of sight remains however a challenging task. In this study, we focused on the development of a tracking system aiming to fill this gap. A robot which consists of a cylindrical magnet of 1 mm diameter is localized using a 2D array of 3D magneto resistive sensors. The system provides a tracking of the robot with a refreshing rate of 2 Hz. The developed tracking algorithm reaches a mean absolute error for the position and the orientation of, respectively 0.56 mm and 5.13° in 2D. This system can be added to existing magnetic navigation systems allowing closed loop control of the navigation. The presented tracking system makes it possible to target applications such as minimally invasive ocular drug delivery.