The Experiments Of A Micro-Robot Systemfor The GI Tract

With the development in the living standard, gastrointestinal problems havebecome one of the most important diseases which threaten or damage the qualityof life. Experts point out the rate of cure of GI problems is normally increasedthe sooner problems are discovered. For now though, traditional endoscope isthe main method in diagnosis. But it will bring great pain to patients in theprocess of inspect, which prevent many people missing the opportunity of earlydetection. Because the capsule endoscope is propelled by GI peristalsis, thephenomenon such as missing inspection will exit. In the funding of NaturalScience Foundation of China and Shanghai science and technology commissionfunded project, the research of micro-robot system which realizes activeinspection is carried out by the technology of micro mechanism, micro sensing,and micro actuator.This paper introduces the robot motion environment firstly, namely GItrack. By analyzing the basic structure, movement feature and physiologicalprosperity of small intestine, with the comparison of common moving mode ofrobot, determines to use the principle of inchworm type. After analyzing the gait,movement efficiency and critical step of the robot, proposing the specific designrequirements of the robot.On the basis of the designing requirements, two kinds of micro DCbrushless motor were chosen as the actuator. The complete robot consists of tworadial clamping mechanisms and one axial telescoping mechanism. In order torealize the purpose of radial clamping and axial telescoping, thedouble-screw-and-nut mechanism and the double-pole-pushpad mechanismwere designed respectively. Furthermore, the design of mechanical construction,the analysis of driving principle, the force analysis of mechanism and the speed of transmission are introduced in detail. What’s more, the simulation softwarewas used to check the designs, ensuring the safety and security of themechanisms. Meanwhile, the sealing design of the robot is introduced.According to the design parameters, some motion parameters are calculated.To match the control of robot’s move, the control system was programmed.The control system can be divided into two parts: the in-vivo receive-actterminal and the in-vireo PC control-transmit terminal. For the purpose ofreducing the power dissipation of the robot, the control algorithm was built intothe in-vivo circuit. Operators can input control command via the upper computer,communicate with the in-vitro circuit through wireless transceiver module. Thein-vitro circuit controls the movement of robot according to the controlcommand received. It also introduces the corresponding program design.After accomplish the assembling, the parameters of the complete robotwere measured. A kind of PVC membrane was used to make up the pipelinemodel and the horizontal and the vertical movement experiments wereconducted to test the movement ability of the robot. In addition, the motionvelocity of the robot before and after sealing was compared. At last, the robotwas tested in the in-vitro pig intestine so as to verify its movement performance.This research according to the characteristics of the small intestine ofhuman body, the appropriate moving mode was adopted. Furthermore, themechanical structure, corresponding hardware and software control system weredesigned on this basis. Finally the robot was tested its motion velocity, verifiedthe movement performance in in-vitro intestine through two experiments. Fromwhat has been mentioned above, the micro-robot system for the GI tract of thisresearch can basically meet the design requirements. And it is a foundation forfurther research in micro-robot system which realizes active inspection; however,there still exist many improvements to be done.