Magnetic Localization for an Intra-abdominal Wireless Laparoscope

In single-incision laparoscopic surgery, the mag-netically driven laparoscope is a promising technique to provide larger workspaces and field of view, relief space for other instruments, and require less incision. To apply closed-loop control which guarantees safety and precise motion, a reliable localization is critical during the operation. In this paper, a real-time magnetic localization method is proposed for a wireless magnetically driven laparoscope. Integrated with two pairs of magnets, the robotic laparoscope is shown to have sufficient coupling force to work in a region where the mapping from capsule pose to magnetic field measurement can be accurately expressed by two single dipole models. Combining multiple sensor feedback, the pose of the laparoscope in six degrees of freedom is obtained at 30Hz, while the position and yaw angle are solved based on Newton-Raphson iteration directly without suffering from measurement drift. The average error is 2.9mm in position detection, and below 5.5° for angular motion.