Structural Design And Simulation Of MRI-Compatible Breast Intervention Robot Based On TRIZ

MRI-guided interventional breast procedure is of great significance for thecheck and treatment of female breast disease. However, due to the strongmagnetic field (1~3T) and limited space of MRI scanners, robotic technology islimited in MRI-guided interventional breast procedure. So it has very importantpractical significance to study MRI-guided breast intervention robot. In thisdissertation, a MRI-guided breast intervention robot is studied. The precisenavigation performance of MRI is combined with dexterous operation ability ofrobot in order to assist doctors to finish interventional breast procedure.Firstly, structural scheme of robot is proposed. According to thecharacteristics of the magnetic resonance environment and interventional breastprocedure, some design requirements are analyzed, including magneticcompatibility requirements, structure compatibility requirements, workspacerequirements and surgical accuracy requirements. As to structure compatibilityrequirements,2003contradiction matrix which is one of TRIZ tools is used tosolve the structural problem of robot in limit space of MRI equipment. A type ofimproved Cartesian coordinate robot is proposed as positioning scheme of breastintervention robot. As to magnetic compatibility requirements, someparamagnetic materials (nylon, POM, non-magnetic stainless steel, etc.) are usedto be compatible with MRI environment. And the compatible problem betweenMRI equipment and drivers is solved by spatial separation principle which is oneof TRIZ tools. Motors are placed away from imaging area as a separate part, andpower is delivered from motors to robot by some flexible shafts. At the sametime, some measures of magnetic shielding are adapted to protect motors so thatmotors can work normally and the image quality will not be affected. As to surgical accuracy requirements, it is analyzed by Su-Field model which is one ofTRIZ tools, and a scheme is proposed to improve surgical accuracy by usingcompression plates to stabilize the shape of breast.After this, a specific structure of the robot which is used to breast biopsy iscarried out, including the design of positioning module, puncturing module,biopsy module, storage module, etc. And a virtual prototype of robot is built bySolidworks.Then kinematics analysis of robot is carried out. The robot coordinatesystem is built by using D-H method, and the forward and inverse solutions ofkinematics are calculated. The robotic simulation model is built byMATLAB/Simulink to get the workspace of robotic endpoint.Finally, the finite element analysis of the robot is carried out. structure staticanalyses of some key components are made by using ANSYS/Workbench, andthe total deformation diagrams and equivalent stress diagrams are gained toprovide the proof of the rationality of structure.The virtual prototype model of breast intervention robot is built and somesimulations including workspace simulation and finite element simulation arecarried out in this dissertation. The results of simulations prove the reasonabilityof the robotic structure, which lay a solid foundation for the further study ofbreast interventional robot.