A Multi-Component Conical Spring Model of Soft Tissue in Virtual Surgery.

With the rapid development of optical system and medical robotic technology, the virtual surgery approach has achieved good progress but also faces many challenges. Physical and mechanical models of soft tissue characteristics have been a hot research topic in this field. In the present investigation, a physical model with a new multi-component conical spring is proposed, which replaces the cylindrical spring of the traditional mass-spring model. In the new model, a multi-component spring structure has been incorporated that consists of a conical spring and a linear spring in series. Based on the analysis of the nonlinear characteristics of soft tissue, the mechanical model was established to correspond better with the physical behavior. To determine the parameters for the mechanical model, the Euler method was deployed. The determination of the model parameters was achieved using physical tests. Result simulation experiments confirmed that the behavior of the new multi-component conical spring model proposed in the present paper gives results that are closer to those obtained from real-world physical tests than were data given by either the mass-conical-spring model or the mass-spring-model. Average difference, maximum difference and mean square error values were used for the evaluation. The accuracy of simulations for soft tissue virtual surgery can be improved by application of the new model developed in the present study.