Design And Development Of An Oral Clinical Virtual Teaching System Based On Force Feedback

With the change in modern medical models and the update in people’s concept of health,people are also more and more concerned about oral health and oral aesthetics,and it is a very urgent task to train qualified young surgeons quickly.Therefore,the force feedback-based Oral Clinical Virtual Teaching System(OCVTS)developed in this thesis can shorten the surgical training cycle of dentists,which is helpful to alleviate the shortage of dentists at the present stage and has important practical significance to meet people’s needs for a better life.This thesis examines the following:1)In the software architecture and process design,this system is based on the software architecture of the C/S(client/server)model,improving the communication method with shared memory and events instead of the network,and designing the QT process as the client and ICT(Image-Collide-Touch)process as the server side of the software,which can effectively improve the real-time performance of the system.Then we analyze the data flow of the whole system,design functional modules from both the front and back sides respectively,and represent the relationship between front and back classes at the same time.2)The development system software is in eight modules,which are the scene construction module,model import module,direction selection module,collision detection module,device management module,force haptic rendering module,information display module,and drilling rendering module.In the collision detection module,the hierarchical envelope box detection algorithm is elaborated.This thesis proposes the AABB envelope box algorithm based on the octree structure,which improves 24.1% compared to the traditional AABB algorithm and 11.8%compared to the binomial tree structure,realizing high real-time and accurate collision detection,and also designs the collision detection process between the needle of the surgical tool turning and the tooth.3)In the force haptic rendering module,firstly,the principle and physical model of force feedback are described,the commonly used algorithms for solving the force feedback physical model are compared,and the prime-spring algorithm with fast solution speed and good real-time performance is chosen to solve the force feedback physical model,the force feedback process uses the God-Object method,and the feedback force magnitude is calculated using Hooke’s theorem.In addition,surgical experiments in which teeth are drilled are simulated by the elimination of voxels in the drilling rendering module.Functional testing and performance testing of the system,the test results show that the system designed and developed in this thesis has a more realistic surgical training environment and surgical process,accurate and efficient collision detection and force feedback,and meets the requirements of the virtual surgery system in real-time.