Study On Magnetic Location Based Tip Tracking And Shape Sensing For Flexible Robot

Minimally invasive surgery is the development direction of modern medical,with the applications of the current optical,mechanical and electrical technology.Replacing the naked eye with vision presentation by the help of the imaging equipment,using thin rigid or flexible instruments to complete the surgical treatment in the internal body,achieving the small trauma and less pain for the patient,doing not damage other tissues or organs,shorting the postoperative recovery time and striving to leave light or no scar features.Traditional surgical robots have the disadvantages of high cost,high techni cal requirements for doctors,large occupation area and so on.At the same time,the operating device is mostly rigid instruments,not easy to fullfill surgery in the curved cavity such as the nasal cavity and oral cavity.Therefore,the research and development of the robot with the small size and a flexible framework which can pass non-linear path is the current development needs and trends.Based on the current design of minimally invasive surgical rob ot,this paper presents a novel wire-driven flexible minimally invasive surgical robot.Compared with traditional surgical robot,this robot can maintain good working performance in small and complex environments,which makes it an excellent choice for minimally invasive surgery.According to the working space and requirements of surgical robots,this paper have designed and optimized the structure system of wire-driven flexible minimally invasive surgical robot,deduced the forward and inverse kinematics models of robot,solved the equation of state in three dimensional space,and verified them with MATLAB simulation.Based on the robot structure design and motion model,the design of the robot's drive control system is realized,and the drive algorithm programming is completed.The robot system platform is set up to carry out the robot collision experiment,the validity and practicability of the robot structure and the driving algorithm are verified.During the operation,not only the position and direction of the tip of the robot need to be obtained,but also the shape information of the robot needs to be obtained so as to avoid harming the patient's other body tissues.In order to control the robot precisely and safely,in this paper,we proposed a magnetic tracking based tip pose and orientation method for wire-driven flexible robots.A small permanent magnet is mounted at the distal end of the robot.Its magnetic field can be sensed with the sensor array.Therefore,position and orientation of the tip can be estimated utilizing the tracking method.A shape reconstruction algorithm based on Bezier curve is carried out to estimate the real-time shape of the robot on ground that the tip pose.With the tip pose and shape display wit h the mapped environment,navigation can be achieved.This method provides the advantages that no sensors are needed to mounted on the robot and no line-of-sight problem.According to the proposed method,we carried out the medical navigation experiment in the 3D test environment made by Lego and the reconstructed 3D skull CT model respectively.The navigation errors of 1.90 mm and 2.07 mm are achieved respectively.The experimental results also proved feasibilities and effectivities of the proposed method.