Intestinal-related diseases all around the world are increasing nowadays, and gradually become stubborn diseases threatening human health, and even lives. Diagnosis methods have attracted more and more attention. This article concerns a non-invasive way, a novel micro-robot, to diagnose intestinal diseases. This proposed micro-robot is a swallowable device, 14 mm in diameter, like a capsule. In order to make it possible for the micro-robot to move forward, backward, or anchor itself at a suspicious lesion point in the intestine with different lumen diameter sections, two key mechanisms have been proposed. One is an expanding mechanism with two-layer folded legs for anchoring. The designed expanding mechanism could realize a large variable diameter ratio, upwards of 3.43. In addition, a pair of specific annular gears instead of a traditional pinion drive is devised not only saving limited space, but also reducing energy loss. The other mechanism is a telescoping mechanism, possessing a self-locking lead screw nut system, which is used to obtain axial motion of the micro-robot. Then, the kinematics and dynamics of the micro-robot are analyzed. After that, the following experiments, including force tests and locomotion tests, are constructed. A good match is found between the theoretical results and the experimental data. Finally, in vitro experiments are performed with a prototype to verify the safety and reliability of the proposed micro-robot in porcine intestine.

Wireless power transfer (WPT) in weak coupling has recently received widespread attention because it could be used to supply energy to capsule robots (CRs), allowing CRs (580 mW needed) to diagnose and treat diseases in the human body. In particular, exciting a three-dimensional (3-D) alternating magnetic field (AMF) for powering CRs has always been challenging since the randomly changing attitude and position can destabilize the induced power received by the coil on the CR. In this article, a novel WPT system based on three-dimensional hybrid transmitting coils (3DHTC) is proposed to generate stable energy for the CR. 3DHTC is a 3-D orthogonal coil system, consisting of a Helmholtz coil pair and two saddle-shaped coil pairs. The dimension of the 3DHTC is Φ70 × 35 mm. It can basically cover a 30 cm × 30 cm area of the human abdomen the design and implementation details of the new 3DHTC system are presented in this article. The 3DHTC system has been proven to excite a uniform and stable AMF covering the CR workspace by both analytical calculation and simulation analysis. Furthermore, a 1-D receiving coil (1DRC, Φ14 × 14 mm) is employed in the experiments to measure the AMF generated by the 3DHTC for its performance evaluation. The experiments illustrate the 3DHTC can supply stable energy of at least 777.63 mW to the 1DRC with randomly changing attitudes and positions, and the corresponding transfer efficiency ranges from 8.1% to 13.61%.