Research Of A Micro-Robot System For Gastrointestinal Tract Inspection Based On Wireless Power Supply

Human gastrointestinal diseases belong to the chronic disease with the high morbidity and high mortality. Both at home and abroad, the traditional endoscopy is the main diagnosis and treatment method according to the digestive tract disease. Endoscopy brings patients great pain and discomfort, causes the digestive tract damage and many complications, and there are blind spots during endoscopy. Capsule endoscopy can realize the gastrointestinal tract noninvasive inspection, however the passive movement of the capsule makes the doctor could not repeatedly observe the suspicious lesions point. To surmount the shortcomings of existing gastrointestinal checking method, research of an active locomotion micro-robot, applicable to the noninvasive gastrointestinal tract inspection, plays an important role in the clinical application.An active locomotion micro-robot system for gastrointestinal tract inspection, which is especially applicable to small intestinal noninvasive test, is developed in this paper. The project is funded under the national 863 project"the research of micro bionic robot to inspect gastrointestinal diseases and wireless energy transmission technology research"(numbers: 2007AA04Z234), and Natural Science Foundation of China"the research of the micro bionic robot system for the noninvasive inspection of the gastrointestinal tract and the wireless energy technology research"(numbers: 60875061). The size of the robot is suitable for moving in the human small intestine, the robot can actively move in the intestine with no damage to the bowel wall, the robot carry a camera system to inspect the small intestine real-time. The communication system of the robot has good performance and the locomotion of the robot can be controlled real-time. The robot is powered wirelessly and can move with no cable.This paper mainly studies the miniature robot system for the gastrointestinal tract inspection, applicable to the noninvasive diagnosis and treatment of the small intestine, the finished work and the research achievements mainly include the following aspects:1. Analyze the environment of the human gastrointestinal tract and propose a locomotion model of the robot which can move in the gastrointestinal tract. Study the physiological characteristics and biomechanical characteristics of the human intestine, along with the analysis of the common drive mode and locomotion mode of the robot, the locomotion mode of inchworm-like peristaltic movement based on the dc motor driver is applied in this robot system. The principle of this locomotion mode is studied and the method of moving forward, moving backward and resident is also analyzed. The critical step of the locomotion in the intestine is calculated and the specific requirements of the robot design are listed in this paper.2. Design the mechanisms of the robot and analysis the mechanics of the mechanism. The robot mechanism is composed of one axial expansion mechanism and two radial clamping mechanisms, which are connected by the universal joint. The axial mechanism is consisted of micro dc motor, 3-level gear reducer and screw transmission. The radial mechanism is consisted of micro dc motor, 3-level gear reducer, differential screw transmission and a pair of radial rod. The axial mechanism actuates the robot to move in the axial direction, so the axial speed and the axial force are analyzed, and the mechanism is tested after assembling. The radial mechanism actuates the robot to move in the radial direction, so the mechanism locomotion of the radial rod is studied, and the mechanism is tested after assembling. 3. Design the control system and the wireless energy transmission system of the robot. The control system is divided into the launch control module in vitro and the receive control module in vivo. The launcher receives the control signals through a serial port from the PC terminal, and launches it out wirelessly. The receiver receives the control signal from the launcher and controls the locomotion of the robot. The wireless energy transmission system is also divided into the launcher and the receiver, the launcher translates the electric energy into electromagnetic energy by resonance, the receiver couples the electromagnetic field by the receiving coil and converts it into electric energy.4. Combined with the control system and the wireless energy transmission system, do the experiments of the designed robot in the simulative intestine and in the pig small intestine in vivo.The robot system developed in this paper can meet the basic requirements of the project. It is beneficial to the further studying of the micro-robot for the noninvasive inspection of the gastrointestinal tract, however there are still many improvements to make.