Design of a steering mechanism for a Tethered Capsule Endoscope

Stomach cancer is one of the most common cancers. Chances of survival of the cancer benefit from early diagnosis. The Tethered Capsule Endoscope (TCE) comes as an alternative diagnostic device to the common gastroscopes. It offers quick and simple endoscopic inspection without any anesthesia on the stomach inner surface. However, the lack of navigation function of the TCE system due to its ultrathin and flexible tether makes it difficult to inspect different sections of the stomach accurately. This paper presents the design of a tendon-driven steering mechanism for the TCE system to achieve omnidirectional control of the capsule. A prototype with a flexible extension tube and a steering section was built. The capsule control model of the steering section was experimentally created. Preliminary experiments in omnidirectional steering control showed that the capsule can be steered to target directions with an average control error less than one degree when bending angles are larger than 20 degree.