Research On Conveying Technology Of Flexible Medical Devices

Flexible medical devices have active bending structure,which can actively control the direction in order to bypass obstacles and achieve dexterous positioning in the anatomical environment.Although flexible medical devices have strong adaptability in the medical field,most of their operations are controlled by doctors using both hands.They have high complexity,low accuracy and radiation hazards during the operation.Aiming at the flexible medical instruments used in the diagnosis and treatment of systemic diseases,this paper develops an assistant interventional system,which can improve the operation of flexible medical instruments,including the delivery and operation of flexible endoscopes and biopsy instruments.The torsional motion state of digestive endoscopes is studied,the precise model of digestive endoscopes is established,and experiments are carried out.The details are as follows:According to the functional requirements of biopsy instruments,the design objectives of biopsy conveyor were put forward.Based on the analysis of design requirements and design criteria,the mechanical structure of biopsy conveyor was designed in detail.Including its rapid disassembly and assembly structure design,clamp head opening and closing driving mode,forward and backward driving mode and biopsy device guiding pipe docking design;draw the three-dimensional solid model of the conveyor,and carry out finite element simulation and verification of the main force components.Aiming at the shortcomings of double-wheel conveyor of endoscope-operated robot,a new four-wheel conveyor mechanism was designed,the three-dimensional model of the four-wheel conveyor was drawn,and the functions of the conveyor were enriched,including mucus scraping,torque sensing and clamping switch.The conveying force of the four-wheel conveyor was tested by experiments to meet the requirements of conveying.A kinematic model of flexible endoscope based on Cossera beam theory is proposed.A model of flexible endoscopy in rotating state is established.The motion state of flexible endoscopy is determined by given boundary value conditions.The 15 first order ordinary differential equations and boundary value conditions obtained are transformed into boundary value problems.Experiments on the conveying speed and accuracy of the biopsy conveyor were carried out to determine the feasibility of the conveying speed and accuracy,and the flexural rigidity and torsional rigidity test platform and torsional angle transfer characteristic test platform of flexible endoscope were established.The bending stiffness,torsional stiffness,modulus of elasticity and Poisson’s ratio of flexible endoscope needed in Cosserat beam theory are determined,and the corresponding state of torsional angle at both ends of flexible mirror is determined.The research work of this paper is an in-depth study on the conveying technology of endoscopic manipulation robot,which is of great significance to the accurate conveying of relevant flexible digestive devices.