Design And Optimization Of Hand-Held Multi-DOF Minimally Invasive Surgical Instruments

Minimally invasive surgery has the advantages of small and hidden incision,accurate cutting,good organ protection,less pain,less bleeding,shorter hospital stay,and fewer complications.Compared with traditional open surgery,the performance of terminal operating instruments in minimally invasive surgery is particularly important.The existing hand-held minimally invasive surgical instruments have defects such as poor maneuverability and dexterity,which make it difficult to carry out surgical operations freely and accurately.Although surgical robots are easy to operate,with high precision and dexterity,they are expensive,bulky and difficult to carry and promote,lack tactile feedback.Aiming at above defects and deficiencies,Thesis carried out the design and research of a new hand-held multi-degree of freedom minimally invasive surgical instrument with the background of laparoscopic minimally invasive surgery,two kinds of hand-held multi-freedom minimally invasive surgical instruments with high flexibility,easy operation,simple structure and low price are designed to improve the flexibility and operability of surgical instruments.The performance requirements of minimally invasive surgery on surgical instruments were analyzed,the process of laparoscopic minimally invasive surgery,the types of surgical instruments,the size requirements,the freedom requirements,the scope of surgical operating force,medical materials and processing technology were studied.After comparing various driving modes,the wire rope driving mode suitable for handheld minimally invasive surgical instruments with multiple degrees of freedom was selected.The geometric structure model of the steel wire rope is established,the force of the steel wire rope on the roller is analyzed,and the mathematical relation between the inlet and outlet tension of the steel wire rope on the roller,the relation between the dynamic friction force and the wrapping Angle,the stress distribution function of the steel wire on the roller were established.According to the mechanical property of the wire rope,the structure of the driving wheel,the guide wheel and the driving wheel were designed,the space path of the wire rope was planned,a "symmetrical structure" was presented to eliminate the motion coupling of the wrist joint deflection and pitching.A variety of minimally invasive surgical instruments for the wrist joint were designed.According to the performance requirements and the constraints of the abdominal minimally invasive surgery environment,the wrist joint scheme of the wire wheel universal shaft and flexible serpentine structure was selected.The end surgical tool,wrist joint,operating rod,and posterior control mechanism of the wire wheel universal shaft wrist joint were designed,and the strength of the key parts of the wrist joint was checked.The spatial range of motion of the end-effector was analyzed.Continuous flexible hand-held minimally invasive surgical instruments with multiple degrees of freedom were designed,a variety of flexible snake wrist joints were studied and compared,the flexibility and flexural fatigue characteristics of the snake wrist joints were analyzed,the related influencing parameters were optimized,the driving structure and the rear control mechanism of the snake wrist joints were designed.