Research On Modeling And Control Strategy Of Rapid Reduction System For Pelvic Fractures

Unstable pelvic fractures are mostly injuries caused by high-energy external forces.With the development of construction,manufacturing,transportation and other industries,the number of patients with pelvic fractures is increasing year by year.Open reduction and internal fixation(ORIF)and closed reduction and external fixation(CREF)are often used in traditional operation.Both methods have obvious shortcomings.The former needs to peel off a large area of soft tissue,which has the disadvantages of wound infection and important nerve injury.While the latter has a narrow scope of application,the reduction accuracy is not high,at the same time,the operation consumes a lot of physical strength on doctors,doctors and patients will be exposed to radiation frequently,affecting their health.The robot has the characteristics of accurate motion control,anti-fatigue,reliable motion path and good repeatability.Since the 1990 s,researchers have worked hard to integrate engineering represented by robotics and medicine represented by orthopedic surgery in order to realize the combination of medicine and industry.There are also a lot of medical treatments about orthopedic surgery robots,but most of them are aimed at the reduction of long bones in the human body.In this paper,combined with the progress of the previous orthopedic reduction robots,a preliminary discussion of an orthopedic robot system that can quickly reduce pelvic fractures.The main research contents are as follows:(1)The architecture of the rapid reduction system for pelvic fractures was designed,and then the overall design is divided into two aspects: mechanical structure modeling design and software system architecture design,and the functional modules of the two are introduced respectively;(2)Combing the related technologies of medical image data preprocessing and 3D modeling.The format and protocol of medical image data in DICOM3.0 standard are explained in detail;the denoising techniques such as adjacent average method and median filtering method are introduced;image segmentation techniques such as threshold segmentation,region growth segmentation and edge detection segmentation are described;the volume rendering technology of medical image mapping method is studied.(3)The three-dimensional modeling system of pelvis is designed and implemented.The fast 3D imaging modules of surface rendering and volume rendering of CT image data of pelvic 3D modeling system are realized by using VTK,Qt and Py Charm as development tools.In addition,the functions of zooming,translation,rotation,3D measurement,establishing spatial coordinate system and deriving STL format are realized.The effect of the above functions is verified by pelvic CT data.(4)The mathematical foundation of UR10 robot motion is constructed,and the forward and inverse kinematics solutions are derived on the basis of D＿H coordinate system and D＿H parameter table.Establish the simulation model of the robot and plan the trajectory through the Robotics Toolbox robot simulation modeling library of MATLAB.