Study On The Endoscopic Micro Robots Operating In Liquid Environment

With the expanding of applied range of minimal invasive surgery (MIS) technology, studies on the autonomic endoscopic micro robots have been more and more important. Many kinds of micro robots have been studied in the past decades for medical use. After the analysis of present research status of endoscopic micro and considering they always operate in the environment with liquid, the dissertation proposed a novel spiral-type non-invasive endoscopic micro robot and its modified micro robot, a tadpole-like micro robot and a Rayleigh stepped micro robots. After making the theoretical and experimental researches about performances of the micro robots, merits and faults of the three kinds of endoscopic micro robots had been compared each other, and a derived endoscopic micro robot which is the tadpole-like micro robot with spiral head has been proposed to operate in blood vessels in the future.The first chapter analyzed the shortcomings of the conventional endoscope system, investigated the present research status of autonomic endoscopic and then pointed out the primary coverage of the dissertation.Chapter two showed the design scheme and the locomotion principle of spiral-type endoscopic micro robot. After the research on the thrust force of the micro robot, the modified spiral-type endoscopic micro robot was presented. A branch system of the image acquisition, wireless transmission and control has been designed to integrate with the endoscopic micro robots.Chapter three provided the nonlinear theoretical model of the spiral-type micro robot. In this chapter, we firstly made experiments about the rheologic behaviors of dog's intestinal juice, human's gastric juice, whole blood and artificial blood. The rheologic behaviors can be expressed with the Casson equation. We also studied on the biomechanical behavior of dog's small intestines experimentally and obtained an equation to express the viscoelasticity performance. The nonlinear theoretical model of the spiral-type micro robot was constructed after coupling the models of operating environment with the innovation Reynolds equations.With the nonlinear theoretical model mentioned above, chapter four studied on the axial thrust force and circumferential factional resistance varied with the characteristic parameters of spiral of the micro robot. We also studied about the influences of the environment character to the locomotion performance theoretically. Chapter five gave the design scheme of the experimental facility of axial thrust force and circumferential frictional resistance and fabricated it to confirm the validity of the nonlinear theoretical model. With the experimental facility, we studied about the axial thrust force and circumferential frictional resistance varied with the characteristic parameters of spiral of the micro robot. Also comparative studies on the large-scale and small-scale spiral-type micro robot have been made experimentally. With the 2 mm diameter micro motor, 4 mm diameter model machines of spiral-type micro robot and it's modified one have been fabricated. Locomotion speeds of micro robotsoperating in isolated pig's intestines have been studied experimentally.Chapter six provided two derived endoscopic micro robots: the tadpole-like microrobot with spiral head and the stepped micro robot. After making theoretical andexperimental researches about performances of the two micro robots, merits and faultsof the three kinds of endoscopic micro robots had been compared each other, and aderived endoscopic micro robot which is the tadpole-like micro robot with spiral headhas been proposed to operate in blood vessels in the future.Chapter seven generalized all the studies of this dissertation and pointed out theinnovations, and then discussed which studies should be made in future.