| The frequently-occurring diseases of human digestive tract causesignificant dangers to human healthcare, and the mechanical-insertendoscope is used for diagnoses as a traditional way. Small intestine islocated in the retroperitoneum of the human body, circuitous and overlapping,which makes it be a dead diagnostic blind area. With the progress of scienceand technology, wireless capsule endoscopy brings the diagnoses and treatsinto a new stage, realizes the non-invasive examination, and provides a newsolution to the small intestine disease. However, due to the non-initiativemotion of the capsule and the lack of diagnostic methods, a concept of anactive locomotion endoscopic-robot system is put forward for furtherresearch. An active endoscopic-robot system able to realize the non-invasivediagnose of the gastrointestinal tract effectively and safely, has become aresearch hotspot with important application feature.The project is funded under the Natural Science Foundation of Chinaprojec（tNo.60875061）, Advanced Manned spaceflight project（No.010203）,and Shanghai Science and Technology Commission Project（No.09DZ1907400）.An active locomotion endoscopic-robot system whichcan work effectively in pig intestine is researched and designed.Firstly, the background and significance of the research on the smallintestine micro-robot are introduced, and the achievement on this researchproject both in domestic and international are cited. According to thedifferent driver modes, recently the new robot systems of research institutionsare divided into three categories: in-vivo driven, vitro driven and Integrated driven. Analyze of the strengths and weaknesses of each system as a designreference.Human intestinal tract is so special environment to motion, and thebiological characteristics of the small intestinal from four aspects aresignificant, that are anatomy, histology, movement and bio-mechanicscharacteristics. With the special physiologic characteristics of small intestine,the motion requirements to intestinal robot are puts forward, so as todetermine the bionic motion as inchworm telescopic mode. With no limbmovement, inchworm telescopic motion is away from the wheel movementrestrictions to better movement stability. The front and rear structure aresymmetrical, much easier to implement forward and back. Combined withmodular design, institutions miniaturization adapts to the intestinal tract asthe narrow working environment. Combining the hyper elastic model whichdescribes the stress-strain relation of the intestinal, a mathematical model thatdescribes the relationship between the design parameters and single stepvalue is deduced. With the practical application of the robot, the mainlydesign requirements are discussed. Determined the drive principle, it choosesthe miniature DC motor as driver. And then it puts forward the mechanicaldesign of the mechanism and the control circuit part.Mechanical units are divided into radial clamping structure and axialextend-retract structure two kinds. The whole system is composed of threeindividual sections, named clamping, extend-retract and clamping structure（short for C-ER-C）. Compared pneumatic type, liquid filling type andmechanical clamping type, the mechanical clamping mode is chosen for moreeffectively locomotion. Mechanical clamping unit is based on double screw,double nut and three mechanical feet, together constituted the atypical crankslider mechanical structure. Axial extend-retract unit is based on screw andnut as transmission. On the basis of the axial extend-retract structure unit ofthe1st generation robot, the2ndgeneration robot changed from one directionextension to both directions. The first generation of robot body diameter is14mm, and the second generation is12.8mm. The control system is mainly divided into hardware circuit system andsoftware system. Hardware circuit includes in-vivo control circuit unit,in-vivo and vitro communication circuit unit, and in-vitro control circuit unit.Compared with1st generation robot, the2nd one adds the limit circuit, andthe micro-controller changed from PIC16F690to PIC24FJ64GA002for thecommunication port requirements for new function circuit. Software systemincludes the in-vivo control program, in-vitro control program, PC controlinterface program and wireless remote control program. Then introduce themotor control module, wireless communication module, nonvolatile storagemodule, and A/D conversion modules.The micro intestinal robot prototype is testedin a simulation and in-vitroexperiment. The robot was tested in both horizontal and vertical simulationtube to get more about the operational capability of the robot in a specialenvironment. The robot is tested in in-vitro experiments by using the pig’ssmall intestine simulating the intestine is well supported by the mesentery,which shows that the performance of the robot is the same as the design, andthe robot is locomotive in the intestinal model. In the end, it summaries allthe design achievement, also analyzes some problems in design, makes asuggestive direction for the further research.From the above, this paper puts forward a kind of bionic locomotionmode for gastrointestinal robot, designs the specific mechanical system andcontrol system, and implements the1st generation and2nd generation robotsystems, through the simulation to analysis of the movement characteristics.And the energy of the robot uses the wireless energy supply way that allowsthe robot a higher independence, laid a good foundation for the followingadditional features. |
PDF Full Text Request