Design And Research Of Integrated System For Diagnosis And Treatment Based On The Drive-Lock Homogeneous Surgical Instrument Platform

Surgical instruments are an important component of minimally invasive surgical robotic systems and their mechanical design directly affects the performance of the system and governs the development and design of other components.Considering the current situation of poor stability of silk-driven surgical instruments,single diagnostic function and lack of intraoperative real-time diagnostic information,this thesis is closely related to the actual needs of minimally invasive surgical operations,designs an integrated system based on a drive-lock homogeneous surgical instrument platform,conducts an in-depth and systematic research using theoretical analysis and experimental verification methods.The main research and the creative results achieved are as follows:1.To meet the requirements for flexible and stable operation of surgical instruments,a drive-lock homogeneous mechanism based on the principle of meshing and locking is proposed,and the principle prototype of the surgical instrument platform is developed.The shaped gear double-threaded array drive system integrates two degrees of freedom bi-directional bending and position locking,the integrated design of the end visualisation unit solves the problem of blind spots in the field of vision and the obstruction of instruments.A feed-forward control method based on transmission return and the construction of a master-slave control system has been used to achieve precise control of the surgical instrument platform,provides a flexible and reliable "access vehicle" for placement into the human abdominal cavity.2.To further unify the "flexible access" and "rigid support" of the surgical instrument platform,a low-melting-point alloy(LMPA)based phase change drive locking mechanism is proposed and a prototype is developed,which utilises the solidliquid phase change properties of LMPA to achieve the integration of large curvature space motion and variable stiffness functions.To address the problem that it is difficult to use rigid kinematics modeling,the relationship between pressure and deformation response is analyzed based on the elastic strain energy theory,and the mapping model between the end position and the driving pressure is established to provide a theoretical basis for its position control.In addition,a heat transfer model for thin-walled multilumen tubes has been developed based on the phase change mechanism of low melting point alloys,and the steady state heat transfer process has been analysed using Fourier’s law of thermal conductivity,and a mapping function between circulating water temperature and rigid-flexible transition time has been established to achieve accurate calculation of rigid-flexible transition time for the surgical platform.3.To enrich the diagnostic functions of the surgical instrument platform,the "execution tools" at the end of the platform have been modularly interchangeable.A prototype of an embedded motorized optical biopsy tool has been developed,which can manipulate a fiber optic beam to obtain high resolution microscopic images in real time for disease diagnosis.The embedded motor design avoids hysteresis and errors in the drive system,enabling precise control of the optical biopsy tool.In addition,the design of a pre-compressed spring-loaded surgical forceps tool is presented and a schematic prototype has been developed.To address the problem of elastic deformation and friction loss in the sheath transmission,a multi-curvature sheath elastic deformation model and transmission model are established based on the differential equation of stress balance of the micro-element sheath,the theoretical calculation equation of the sheath transmission resistance and elastic elongation is proposed using Coulomb’s friction law,and the manipulation accuracy of the sheath transmission is improved by introducing the initial preload force and hysteresis stroke compensation,provide a basis for accurate control of sheath drives in confined spaces and with multiple tortuous path constraints.4.To obtain high-resolution microscopic images for "optical biospy" with high accuracy,a wide-field fluorescence microendoscopy system and a confocal laser microendoscopy system were designed and built,and an ultra-flexible acid-soluble fibre optic transmission beam was used to achieve real-time acquisition of highresolution microscopic images under complex pathways.An approach to integrate a high numerical aperture objective at the distal end of the fibre optic image transmission bundle is proposed to improve the microscopic image resolution by a factor of 1.92.To address the narrow field of view of microscopic images,the Demons algorithm based on template matching of mutual information measures,grey-scale mean squared difference sum and boundary distance weighting algorithm are used to align and fuse microscopic image sequences to synthesize large area microscopic panoramic images,enabling doctors to objectively diagnose diseases.5.Based on the above research,the above mentioned drive-lock homogeneous surgical instrument platform,interchangeable treatment tools,optical diagnostic system and microscopic image stitching software are integrated to form an treatment system and experimental research is carried out.The experimental evaluation of the motion,locking,visualisation,insertion,scanning,microscopic image stitching and interchangeability of the system showed the feasibility and clinical application potential of the integrated system for insertion into the human body.