Design and Fabrication of a Motor Legged Capsule for the Active Exploration of the Gastrointestinal Tract

This paper describes a novel solution for the active locomotion of a miniaturized endoscopic capsule in the gastrointestinal (GI) tract. In particular, the authors present the design, development, and testing of a legged locomotion system embedded in a capsule (with a volume of about 4-5 cm3) and actuated by a brushless minimotor. The actuation mechanism and transmission mechanism are described in detail in order to highlight the compactness of the overall design. This device is provided with four superelastic legs, allowing large stroke advancement in the GI tract, and a CMOS frontal camera, for diagnostic purposes. A dedicated electronic board for controlling the opening angle of the legs and adjusting their speed has been developed. In order to investigate the motion ability of the device, a set of experiments has been carried out. Four different types of superelastic legs have been designed and tested with the objective to identify the best leg configuration for capsule locomotion. Experimental results demonstrate that the device can travel in the digestive tract with a typical speed ranging between 10 and 40 mm/min.