Micro-intestinal robot with wireless power transmission: design, analysis and experiment.
BACKGROUND
Video capsule endoscopy is a useful tool for noninvasive intestinal detection, but it is not capable of active movement; wireless power is an effective solution to this problem.


METHODS
The research in this paper consists of two parts: the mechanical structure which enables the robot to move smoothly inside the intestinal tract, and the wireless power supply which ensures efficiency. First, an intestinal robot with leg architectures was developed based on the Archimedes spiral, which mimics the movement of an inchworm. The spiral legs were capable of unfolding to an angle of approximately 155°, which guaranteed stability of clamping, consistency of surface pressure, and avoided the risk of puncturing the intestinal tract. Secondly, the necessary power to operate the robot was far beyond the capacity of button batteries, so a wireless power transmission (WPT) platform was developed. The design of the platform focused on power transfer efficiency and frequency stability. In addition, the safety of human tissue in the alternating electromagnetic field was also taken into consideration. Finally, the assembled robot was tested and verified with the use of the WPT platform.


RESULTS
In the isolated intestine, the robot system successfully traveled along the intestine with an average speed of 23 mm per minute. The obtained videos displayed a resolution of 320 × 240 and a transmission rate of 30 frames per second. The WPT platform supplied up to 500 mW of energy to the robot, and achieved a power transfer efficiency of 12%.


CONCLUSIONS
It has been experimentally verified that the intestinal robot is safe and effective as an endoscopy tool, for which wireless power is feasible. Proposals for further improving the robot and wireless power supply are provided later in this paper.
820 Institute, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China. Electronic address: shiyu359@163.com.
Yu
Y
Shi
820 Institute, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
Guozheng
G
Yan
820 Institute, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
Wenwen
W
Chen
820 Institute, Department of Instrument Science and Engineering, School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240, People׳s Republic of China.
Bingquan
B
Zhu
D001696:Biomechanical Phenomena; D053704:Capsule Endoscopy / Q000295:instrumentation*; D003198:Computer Simulation; D011211:Electric Power Supplies; D004574:Electromagnetic Fields; D016099:Endoscopy, Gastrointestinal / Q000295:instrumentation*; D004867:Equipment Design; D006801:Humans; D007422:Intestines / Q000473:pathology*; D060526:Magnetic Fields; D009038:Motion; D065287:Robotic Surgical Procedures / Q000295:instrumentation*; D012371:Robotics; D059015:Wireless Technology / Q000295:instrumentation
Archimedean spiral legs; Electromagnetic coupling; Frequency stabliltiy; Intestinal robot; Wireless power transmission