Design and analysis of a magnetically actuated and compliant capsule endoscopic robot

In this paper, we propose a compliant and tetherless magnetic capsule endoscopic robot. The proposed capsule robot has two key features. First, it has one extra degree of freedom axial contraction capability to perform additional tasks such as a drug releasing, a drug injection, or a biopsy. Also, design features of the magnetically deformed capsule robot are introduced. Its characteristic deformation curve, which was measured using an indentation setup, presents not only the deformation behavior of the magnetic capsule robot but also considerations in the capsule design process. Next, by implementing a magnetically actuated rolling locomotion scheme, the capsule can be controlled externally using a permanent magnet. The proposed magnetic capsule robot is anchored on a tissue wall by the magnetic attraction and rotated by a magnetic torque. This behavior allows a stable locomotion of the magnetic capsule robot and its orientation is controllable during locomotion. To verify the feasibility of proposed locomotion method and the compliant capsule's shape deformation, the magnetic capsule robot was actuated in a synthetic stomach model. The experimental results show that locomotion behavior of the capsule is stable and a successful tracking performance of the proposed magnetic actuation method; average distance gap between the capsule and the external magnet was only 20% of the capsule's body length. Such a soft and tetherless capsule robot can potentially enable minimally invasive diagnostic and treatment applications for stomach diseases.