An Optically Aided Magnetic Tracking Approach for Magnetically Actuated Capsule Robot

Embedded with an internal permanent magnet (IPM), a magnetically actuated capsule (MAC) robot can be controlled inside gastrointestinal (GI) tract by an external permanent magnet (EPM) outside of human body. Locomotion control of MAC robot can be achieved based on precise pose feedback that is usually carried out by magnetic tracking. However, the coupling of internal and external magnetic fields will deteriorate the accuracy. To solve this problem, we propose a novel optical-magnetic fusion tracking framework in this article, which can be applied to track the MAC robot in real time. The proposed method utilizes the prior-known pose of EPM estimated from the optical tracking method to decouple IPM's magnetic field from the composite magnetic field to achieve higher tracking accuracy of wireless capsule endoscopy (WCE). Moreover, magnetic field methods have been analyzed to validate the accuracy of theoretical description of magnetic field. The proposed strategy is validated by both static and dynamic experiments. The average position and orientation errors are 2.6 mm and 1.54 degrees, respectively.