A Multi-component Conical Spring Model Of Soft Tissue In Virtual Surgery

With the rapid development of medical system and computer technology,precision medicine has become a research hotspot in the current medical development.As an important part of precision medicine,virtual surgery is facing many challenges while making good progress.Virtual surgery mainly constructs the real human soft tissue through modeling method,and carries on the real-time operation according to the interactive equipment,so as to realize the simulation of clinical surgery.However,the current soft tissue modeling methods can not meet the real-time and accuracy requirements of virtual surgery at the same time,resulting in the decline of intraoperative experience.Therefore,this work chooses to refine the mass spring model without affecting the real-time performance to improve the visual immersion and tactile immersion in virtual surgery.The main contents are as follows:(1)In this work,based on the analysis of the mechanical properties of soft tissue,the conical spring with similar mechanical behavior is selected as the analysis object,and the behavior of the two under stress is compared through the system.Finally,the conical spring is selected to replace the cylindrical spring in the traditional mass spring model,and a multi-component conical spring module is constructed,which is composed of conical spring and linear spring in series.(2)Based on Newton’s law of mechanics,the mechanical motion equations among the multi-component conical spring model are established.Then,the motion equations of the whole body model are constructed,and the improved Euler method is applied to the calculation of the differential equations of the force bearing points in the model to realize the deformation simulation.(3)The data collected from the real mechanics experiment are taken as the input variables of the model,and the unknown parameters are solved by the least square method in the simulation environment.The mechanical behaviors of the model and the real pig liver soft tissue in the linear and nonlinear stages were compared and analyzed.(4)In simulation environment and finite element analysis software,the mechanical simulation experiment and axial compression dynamic simulation experiment of soft tissue model and real soft tissue were carried out respectively.At the same time,the simulation of3 D visualization is carried out in Open GL environment based on C++.Through the systematic analysis of the simulation results in the experiment,it is further obtained that the multi-component conical spring model has more similar mechanical behavior with the real soft tissue,so as to achieve the purpose of improving the accuracy of soft tissue simulation without affecting the real-time performance.