Magnetically Actuated Capsule Robots: A Review

Capsule endoscopy is a procedure that uses a tiny wireless camera inside a capsule endoscope to capture pictures of the patient's gastrointestinal tract for diagnosis. Gastrointestinal examination has been revolutionized by capsule endoscope owing to its simplicity and non-invasiveness. However, at this stage, the capsule endoscope has a weak controllable locomotion capability and does not have extended functions such as biopsy, localization, and therapeutics, which has become the main obstacle to expanding its application. The use of an external magnetic field to actuate the capsule endoscope has the advantages of simple response structure inside the capsule and remote energy supply, which can expand the above-mentioned functions of the capsule endoscope and develop into a multifunctional capsule robot. This paper analyzes two types of magnetic actuation systems for magnetically actuated capsule robots, discusses research on the functions of magnetically actuated capsule robots in active locomotion, anchoring, biopsy, localization, therapeutics, wireless power supply, and multi-capsule robot collaboration, and points out the existing problems and future development directions of magnetically actuated capsule robots.