Research On Low-cost Digestive Tract Endoscope Device Based On Water Pressure Drive

With the development of minimally invasive surgery,natural orifice surgery(NOS)was proposed as a new surgical procedure.It doesn’t have abdominal incision,complications after surgery,and surgical scars.The current gastric cancer screening device is performed through a natural lumen,and the main tool is a flexible endoscope.However,it has several limitations including high cost,complicated sterilization,poor portability and unstable platform.In this paper,the difficulty of gastric cancer screening,based on the water-driven approach,theoretical analysis and experimental research are carried out,and two endoscopic devices for gastric cancer screening are proposed.The specific contents of this article are as follows:Firstly,according to the medical requirements of the endoscope screening device,a braided tube structure made of a phase change material is designed based on the excellent telescopic characteristics of the braided structure.The device with a CCD camera has a length of 250 mm,a maximum outer diameter of 16 mm.The driving method is designed and analyzed.The water jet is used to drive the nozzle to complete the scanning,and the cold water is used to complete the tube stiffness change.Then,based on the device designed above,for the rigid-flexible conversion method using wire transmission,a water-jet driven endoscope device based on the software robot is designed again to improve the scanning range.The maximum outer diameter of the device is 13 mm,which is divided into three parts: soft body part,micro valve and rigid-flexible transformation.The driving method is designed and analyzed.The water spray was used to drive the nozzle to complete the scanning,and the balloon and Nitinol wire are used to complete the stiffness change of the soft part.Finally,relevant experiments are carried out on the established theoretical models and the prototypes.The experimental results of braided tube deflection test and temperature change show that the stiffness in the rigid state is about 16 times than the stiffness in the flexible state,and the transition temperature does not exceed 15 seconds.Shape locking and shape holding experiments of braided tubes show that the shape of the outer sheath is locked with an error of 11.7±1.8 degrees and the maximum load force is 1.17 N.The results of soft bending experiment show that the maximum bending angle of the soft body part is 67°,and the water pressure at this time is about 134 k Pa.The experimental results of the micro-valve opening and closing characteristics prove that the micro-valve base length is 1.7mm,and there is obvious opening and closing characteristics.The water jet force and the workspace evaluation prove that the water jet does not cause harm to the human body,and the device is able to cover a large workspace in flexible state by water-jet.Scanning experiments have demonstrated the feasibility of the device.